Search

Cavitation is an essential factor in the deterioration of the hydraulic performance of centrifugal pumps. The study of cavitation fault diagnosis can help avoid or reduce the damage it causes. The vibration and noise analysis method can predict the incipient cavitation more accurately. In order to improve the accuracy of cavitation fault diagnosis, this paper studies the distribution of vibration and noise measuring points for centrifugal pump cavitation diagnosis. The research object is a centrifugal pump with an inducer and splitter blades. Vibration acceleration sensors and hydrophones were used to collect structural vibration and liquid-borne noise signals at different positions of the pump unit. Root-mean-square (RMS) and fast Fourier transform (FFT) methods were used to construct spectrums of vibration and noise signals with different NPSH and compare the sensitivity of different measuring points to the inception and development of cavitation. In addition, the SST k-ω turbulence model and Zwart cavitation model were used to study the cavitation volume distribution in the pump under different cavitation stages. By setting monitoring points at the impeller outlet, the frequency domain signal distribution of pressure pulsation was studied. The results show that the vibration acceleration measuring points at the pump inlet flange and pump axial position, and liquid-borne noise measuring point at the inlet position, are more sensitive to the diagnosis of cavitation fault. Motor current is also the basis for judging the inception of cavitation. Moreover, as the cavitation intensifies, the dominant frequency signal of the pressure pulsation in the pump is partially shifted.

V avtomobilski industriji se dandanes precej pozornosti namenja tako analizi izvora kot tudi obvladovanju akustičnega hrupa. V uvodnem delu se osredotočim na ozadje te tematike in predstavim, kako je prišlo do zahtev po dodatnem razumevanju vpliva močnostnega pretvornika na akustični hrup motorja. Sledi opis modeliranja električnega pogonskega sistema (EPS) in posameznih podsistemov, kjer podrobneje opišem tokovno regulacijo v rotorskem koordinatnem sistemu, modulacijski postopek, močnostni pretvornik in modela električnega motorja. Modela motorja, tako linearni (LMEM) kot nelinearni (NMEM), modeliram v koordinatnem sistemu rotorskega polja, za kar je nujno razumevanje transformacij med sistemi. Ko je v EPS uporabljen LMEM, največ poudarka namenim harmonski analizi statorskih tokov in navora ter dodatno opišem delovanje EPS. V nadaljevanju se osredotočim na modeliranje nelinearnega modela EPS (NMEPS) z metodo končnih elementov, kjer NMEM parametriziram s tokovno odvisnostjo magnetnega sklepa. Rezultat dinamične simulacije NMEPS v okolju Simulink so statorski tokovi, ki vsebujejo tako časovne kot prostorske harmonike. Omenjeni tokovi magnetijo zračno režo, kar ima neposreden vpliv na statorske radialne sile. S predstavljenim postopkom nato uvozim tokove s harmonsko vsebino iz NMEPS v okolju Simscape Electrical kot vzbujanje pri magnetostatični analizi v programskem okolju Motor-CAD. Za referenco kot vzbujanje uporabim še idealni nastavljivi napetostni vir, nato pa analiziram vpliv višjeharmonskih komponent statorskih tokov na izhodne veličine analize. V zaključku magistrske naloge primerjam simulirane radialne sile pri obeh magnetostatičnih analizah. Dodatno z analizo merjenih vibracij na ohišju električnega motorja ocenim, da zgolj ta nivo modeliranja ni dovolj za predvidevanje vibracij. Zato z blokovnim diagramom predlagam sosledje simulacij za nadgradnjo naloge v prihodnje. Nowadays, the automotive industry lays great emphasis on the origin of acoustic noise and its attenuation. The introductory section focuses on how the inverter affects the acoustic noise of the electric motor. This is followed by a description of the modelling of the Electric Drive System (EPS) and the individual subsystems, where the further focus is placed on the definition of the current control in the rotor coordinate system, the modulation process, the inverter, and the Electric Motor models. The motor models, both linear (LMEM) and nonlinear (NMEM), are modelled in the rotor field coordinate system, which requires application of coordinate transformation between stationary and rotary systems. When LMEM is used in the EPS, most attention is paid to the harmonic analysis of the stator phase currents and of the torque, which is succeeded by a description of the EPS. The thesis then examines the modelling of a nonlinear model of the EPS (NMEPS) using the finite element method, where the NMEM is parameterised using non-linear current-flux relationship. The dynamic simulation of the NMEPS in the Simulink environment results in stator phase currents, that comprise both time and space harmonics. These currents excite magnetisation in the air gap, which directly impacts the stator radial forces. Using the presented procedure, the harmonic-content currents from the NMEPS are imported in the Simscape Electrical environment for excitation in the magnetostatic analysis in the Motor-CAD software environment. The ideal adjustable voltage source is also applied for the excitation, which is followed by the examination of the influence of the higher harmonic components on the output quantities of the analysis. In the conclusion, a comparison between the simulated radial forces in the two magnetostatic simulations is drawn. By analysing the measured vibrations on the electric motor housing, an additional deduction is made that suggests that this level of modelling alone is not sufficient to predict the vibrations. Therefore, further enhancement steps are suggested.

Toplotne črpalke se vse pogosteje pojavljajo ob domovih, saj so zaradi uporabe obnovljivih virov varčnejše in oddajajo tudi manj emisij CO2. Poleg tega Eko sklad letno razpiše več subvencij, ki financirajo vse od 25 % do 100 % stroškov postavitve toplotne črpalke, kar je za končnega uporabnika zelo privlačno. Toplotne črpalke na slovenskem trgu morajo biti narejene v skladu s slovenskimi zakoni. Naredili smo pregled slovenske zakonodaje ter evropskih direktiv. Za primerjavo smo preučili še, kako hrup toplotnih črpalk urejata Avstrija in Švica. Po naboru toplotnih črpalk vseh treh tipov smo naredili ekonomsko, energetsko in okoljsko analizo za vsako toplotno črpalko. V ospredje smo postavili toplotne črpalke tipa zrak / voda, ker oddajajo hrup v okolje. Naredili smo tudi pregled možnih rešitev, ki se ponujajo na slovenskem trgu. Za ocenitev najprimernejše in pregled zavedanja smo naredili anketo med splošno populacijo, intervjuje s ponudniki, Inšpektoratom za okolje za okolje in prostor RS in Eko skladom, saj nas je zanimala obravnava hrupa. Na podlagi rezultatov smo s pomočjo programa DEXi ugotavljali primernost vseh toplotnih črpalk, ki smo jih obravnavali v delu. Heat pumps are increasingly appearing next to homes, as they represent a more economical heating technology, because they use renewable sources for energy and, as a result, emit less CO2 emissions. In addition, the Eco Fund annually tenders several subsidies that finance the installation of a heat pump from 25% to 100%, which is very attractive for the end user. Heat pumps on the Slovenian market must be made in accordance with Slovenian laws. We reviewed Slovenian legislation as well as European directives. For comparison, we looked at how Austria and Switzerland regulate the noise of heat pumps. After a set of heat pumps of all three types, we made an economic, energy and environmental analysis for each heat pump. We put air/water type heat pumps in the foreground because they emit noise into the environment. We also made an overview of possible solutions offered on the Slovenian market. In order to assess the most appropriate and check awareness, we conducted a survey among the general population, interviews with providers, the RS inspectorate and Eko sklad, as we were interested in the treatment of noise. Based on the results, with the help of the DEXi decision-making program, we determined the suitability of all the heat pumps that we discussed in the work.

Akustični dušilci za izpihovanje zraka skozi šobo se uporabljajo pri različnih sistemih, kjer stisnjen zrak ekspandira v prostor. V nalogi smo primerjali rešitve na obstoječem dušilcu za izpihovanje zraka na osnovi granuliranega materiala. Želeli smo oceniti vpliv granuliranega materiala na znižanje hrupnosti. Opravili smo vrsto meritev, katere smo računsko ovrednotili. Preliminarni izračuni nakazujejo da se z manjšanjem velikosti granularnih zrn povečuje učinek dušenja hrupa. Najbolj učinkovita rešitev je zmanjšala raven hrupa za okoli 10 dBA. S spremembo geometrije obstoječega dušilca bi lahko še dodatno optimizirali njegovo učinkovitost. Acoustic silencers for compressed air are used in various systems where compressed air expands into the room. In the task, we compared the solutions on the existing acoustic silencer with added granular materials. We wanted to evaluate the influence of granular materials on noise reduction. We performed a series of measurements, of which we computationally evaluated. Preliminary calculations show that as the size of the granular grains decreases, the noise dampening effect develops. The most effective solution reduced the noise level by around 10 dBA. By changing the geometry of the existing silencer, its efficiency could be further optimized.

Magistrsko delo obravnava problematiko odprtih delovnih prostorov, znanih kot ang. open space offices. Zanje je značilna večja kvadratura, odprtost, preglednost ter prosta prehodnost, predelnih sten je malo oz. so ostale le najnujnejše. Takšen trend ni vezan le na pisarniške prostore, temveč na vse prostore namenjene uporabnikom. To pomeni, da se na enem mestu združujejo različne oblike dela, vsako s svojimi specifičnimi značilnostmi. Pri tem se uporabniki omenjenih prostorov srečujejo z doslej manj pogostimi težavami npr. povečana glasnost, hrup, pomanjkanje miru ter zasebnosti, neprimerna osvetljenost delovnega mesta itd. Raziskave, ankete ter intervjuji s posamezniki, ki pogosto delajo v takšnem okolju, so pokazali, da obstajajo možnosti za izboljšanje njihovega delovnega okolja. Informacije, ki sem jih pridobila s pomočjo analiz, sem uporabila kot izhodišče pri oblikovanju produkta, ki se osredotoča predvsem na problematiko akustike v odprtih delovnih prostorih. Pri osnovanju produkta sem določila temeljna izhodišča, kot so prilagodljivost, premičnost, modularnost itd. This master thesis researches all the problematic aspects of open space offices. What is typical for this kind of space is a large surface area, very open, transparent and mainly without walls. This trend is not only seen at offices, but also all the spaces designed for users. Users of this spaces are usually complaining about increased volume, noise, lack of peace and privacy, improper illumination of the workplace, etc. Research, surveys and interviews with individuals who often work in such an environment have shown that there are opportunities to improve their work space. I used the information I have obtained with the help of analyses as a starting point for the design of the product, which focuses primarily on the problem of acoustics in open working spaces. When designing the product I have set out basic principles, such as flexibility, mobility, modularity, etc.

V današnjem času je prisoten trend zmanjševanja hrupnosti transformatorja, kar nakazujejo kupčeve zahteve. Zaradi tega smo pri izdelavi transformatorja primorani nenehno iskati nove rešitve. Velik del hrupnosti transformatorja je odvisen od hrupnosti navitja. S stabilnostjo navitja zmanjšamo hrupnost le-tega. To dosežemo, če zagotovimo dovolj veliko silo stiskanja navitja. Obstoječi način fiksiranja navitja je izveden z vzmetmi in je stroškovno, varnostno ter montažno dokaj nekonkurenčno. Vpeljali smo nov način fiksiranja z lesenimi zagozdami. Ta je olajšal in skrajšal čas montaže navitij. Pri tem smo morali upoštevati dejstvo, da se višine navitij med montažo lahko spreminjajo. Zaradi tega smo morali določiti ustrezne dimenzije in oblike zagozd. Višina navitja se spreminja tudi zaradi procesa sušenja, zato smo pred sušenjem in po njem izvajali meritve in na podlagi rezultatov dodatno prilagodili zagozde. Due to a trend of reducing the noise of the transformer, which is indicated by customer requirements. Due to this, we are constantly forced to look for new solutions in the manufacture of transformers. Much of the noise of a transformer depends on the noise of the winding. The stability of the winding reduces the noise level. This is achieved by providing a sufficiently large compressive force of the winding. The existing method of fixing the winding is made with springs and is quite uncompetitive in terms of cost, safety and installation. We introduced a new way of fixing with wooden wedges. The new method has facilitated and shortened the assembly time of the windings. We had to take into account the fact that the heights of the windings can change during installation. Because of this, we had to determine the appropriate dimensions and shapes of the wedges. The height of the winding also changes due to the drying process, so we performed measurements before and after drying, and based on the results, we further adjusted the wedges.

Uvod: Problematika hrupa in zvočne klime v vzgojno-varstvenih zavodih je z vidika graditeljstva pogosto spregledano področje. Ta pomembno in negativno vpliva na zdrave razmere, razumljivost govora, udobje otrok in zaposlenih ter zmanjšuje njihovo delovno storilnost in učinkovitost. Namen dela: Namen naloge je bil na študiji primera z vidika zvočne izoliranosti zunanjih in notranjih ločilnih elementov ter prostorske akustike preučiti problematiko čezmernih ravni hrupa v izbranem vzgojno-varstvenem zavodu. Problematika se obravnava celovito, pri čemer se upoštevata tako gradbeno-tehnični kot tudi javnozdravstveni vidik. Metode dela: Študija primera obravnava tri stavbe enote Vrtca Jarše v Ljubljani. V petih karakteristični igralnicah smo izmerili zvočno izolirnost zunanjih in notranjih ločilnih elementov ter odmevne čase. Meritve so bile izvedene brez prisotnosti otrok. Uporabljen je bil konstanten vir hrupa. Nato smo s programoma ARTIE in HRUP 13 modelirali prostore in konstrukcijske sklope ter prišli do računskih vrednosti. Izmerjene in izračunane rezultate smo primerjali z zakonsko predpisanimi vrednostmi. Izvedena je bila standardizirana anketa zaposlenih o subjektivni oceni problematike hrupa v vrtcih. Na podlagi pridobljenih rezultatov so bila izdelana priporočila za dejansko sanacijo. Rezultati: Študija je pokazala, kako pomembni sta primerna zasnova in izvedba zunanjih ter notranjih konstrukcijskih sklopov tako za prenos zvoka preko zraka kot tudi za prenos zvoka po konstrukciji. V vzgojno-varstvenih zavodih je dnevna svetloba v prostorih izjemnega pomena in posledično so transparentni deli stavbnega ovoja velikih površin potencialna šibka točka pri prenosu hrupa v notranjost. Zato je potrebno pri načrtovanju transparentnih delov fasadnega ovoja upoštevati njihovo lego in sestavo. Pri obnovah se lahko problematiki izognemo s primerno izbiro dobro zvočno izolativne zasteklitve. Raziskava je pokazala, da so, tako kot zunanji viri hrupa, pomembni tudi notranji viri. Poleg hrupa, ki ga povzročajo varovanci zavoda, je velik vir hrupa obratovalna oprema. Posledično je poleg zasnove zunanjih in notranjih ločilnih elementov pomembna tudi izbira materialov za zaključne sloje konstrukcijskih sklopov v varovanih prostorih (padci igrač, optimalni odmevni časi itd.) Zaključek: Naloga ima veliko uporabno vrednost tako za prenove kot tudi novogradnje na konkretnem primeru je prikazan pomen celovitih ukrepov pri reševanju problematike čezmernih ravni hrupa v vzgojno-varstvenem zavodu. Introduction: The issue of noise and acoustics in educational institutions is an often overlooked from the view of building construction. The latter has a significant impact on unhealthy conditions, speech intelligibility, discomfort of children and employees, and reduces work productivity and efficiency. Purpose: The purpose of the master thesis was to analyse the excessive noise levels in a selected early childhood care and education institution from the view of sound insulation of external and internal structural assemblies and room acoustics. The issue is addressed comprehensively, taking into account both the technical aspects and public health. Methods: The case study deals with three buildings of the Jarše kindergarten unit in Ljubljana. In five characteristic playrooms, we measured the sound insulation of external and internal separation elements, as well as the reverberation times. Measurements were performed without the presence of children. A constant noise source was used. Then, with the ARTIE and HRUP 13 programs, we modeled the premises and structural assemblies, and arrived at the calculated values. The measured and calculated results were compared with the required values. A subjective assessment of noise issues in kindergartens was conducted. Based on the obtained results, recommendations for actual remediation were made. Results: The study showed the importance of proper design and implementation of external and internal structural assemblies, both for the airborne noise and impact nose. Since daylight is extremely important in educational institutions and large transparent parts of the building envelope are consequently a potential weak point in the transmission of noise to the interior, it is necessary to take into account the position and composition of these. When renovating, the problem can be avoided by choosing the right soundproof glazing. Research has shown that just like external sources of noise, internal sources are also important. In addition to the noise caused by the inmates of the institution, a major source of noise is operating equipment. Consequently, in addition to the design of external and internal separating elements, the choice of materials for the final layers of structural assemblies in protected areas (toy falls, optimal reverberation times,…) is also important. Conclusion: the task has great useful value for both renovations and new constructions the concrete example shows the importance of comprehensive measures to solve the problem of excessive noise levels in the educational institution.

Vpliv okolja na sisteme za razpoznavo govora Environment influence of speech recognition systems

Razvili smo dušilec za komprimiran zrak. Uporaben je na adsorpcijskih sušilnikih zraka, ki pri delovanju povzročijo izpust večje količine komprimiranega zraka iz rezervoarja, pri tem pa nastane hrup. V nalogi smo izdelali več idejnih rešitev, katere smo preverili z računalniško simulacijo tekočin, nekatere smo pa tudi eksperimentalno preverili in primerjali z obstoječo rešitvijo. Najboljša eksperimentalna rešitev nakazuje znižanje hrupnosti za približno 6 dB, kar ustreza približno 4x nižja zvočna raven hrupa. We developed a compressed air silencer. It is useful on adsorption air dryers, which cause a large amount o fair to be released during operation, creating noise. In the thesis, we created several conceptual solutions, which we tested with computational fluid dynamics, some of the solutions were also tested experimentally and compared to the existing solution. The best experimental solution suggests a noise reduction of about 6 dB, which corresponds to about 4x lower sound levels of noise.

Hrup je neprijeten in nezaželen zvok, ki vzbuja nemir. Skozi čas se je hrup pričel obravnavati kot onesnaženje, predvsem z vidika elit. Industrijska doba je prinesla tehno občutenja, ki so penetrirala vsakdan prebivalstva. Z uporabo sodobne tehnologije je prišlo do zvočnega vojskovanja in nasilja. Zvočne krajine so akustična kompozicija prekrivanja različnih zvokov, integracija znanstvenih disciplin pa daje pomen zvočnih ambientov na vitalno delovanje ljudi in živali. Vplivi na fiziologijo telesa in zdravje ljudi so dokazani, vidni so tudi vplivi človeka na biosfero, ob čedalje večjem onasnaževanju morja. Virov hrupa je mnogo, a bistveni so cestni, železniški, zračni promet ter tudi hrup naprav. Nova tehnologija zahteva premislek in uporabo previdnostnega načela v mednarodni skupnosti, še posebno, ko gre za ogrožanje redkih živalskih vrst, ki so občutljive na zvoke. Evropska unija je prepoznala hrup kot pereč problem sedanjosti in čedalje bolj urbanizirane prihodnost, sprejeta Direktiva 2002/49/ES pa služi kot akt harmonizacije okoljskega hrupa. Prenos Direktive 2002/49/ES v slovenski red izkazujeta Uredba o ocenjevanju in urejanju hrupa v okolju in Uredba o mejnih vrednostih kazalcev hrupa v okolju, ki določata metode vrednotenja hrupa. Praksa sodišč v povezavi s čezmernim hrupom je bogata, tako na evropski kot nacionalni ravni. Nacionalni programi varstva okolja naslavljajo probleme hrupa in predpisujejo ukrepe za zmanjševanje okoljskega hrupa. Nova tehnologija omogoča pametno prostorsko načrtovanje za zmanjšanje hrupa, a so vprašanja pravice do zasebnosti neizogibna. Noise is an unpleasant and unwanted sound that evokes restlessness. Over time, noise began to be treated as pollution, especially from the point of view of elites. The industrial age brought techno sensations that penetrated the everyday life of the population. The use of modern technology has led to sound warfare and violence. Sound landscapes are an acoustic composition of overlapping different sounds, and the integration of scientific disciplines gives the meaning of sound ambiences to the vital functioning of people and animals. The effects on the physiology of the body and human health have been proven, and the effects of humans on the biosphere are also visible, with increasing pollution of the sea. There are many sources of noise, but the biggest are road, rail, air traffic, and also the noise of different devices. New technology requires consideration and application of the precautionary principle in the international community, especially when it comes to endangering rare species that are sensitive to sounds. The European Union has recognized noise as a burning problem of the present and the increasingly urbanized future, and the adoption of Directive 2002/49/ ES serves as an act of harmonization of environmental noise. The transposition of Directive 2002/49/ ES into Slovenian law is demonstrated by the Decree on the assessment and regulation of environmental noise and the Decree on limit values for environmental noise indicators, which determine evaluation methods. Courts practice concerning excessive noise is rich, both at the European and national level. National environmental protection programs address the problem of noise and prescribe measures to reduce noise pollution. New technology enables smart spatial planning to reduce noise, but privacy rights issues are inevitable.

Na izbranih primerih stanovanjskih stavb (različne sestave stavbnega ovoja) smo opravili kombinacijo meritev in izračunov dejanskih vrednosti zvočne izolirnosti zunanjih ločilnih elementov. Obravnavali smo vpliv prometa, toplotne črpalke ter hrupa cerkvenih zvonov. Rezultate meritev notranjih ravni hrupa v varovanih prostorih stavbe smo primerjali z zahtevami ter priporočili. Zvočno izolirnost fasade smo izračunali z enačbo in programom Hrup ter ugotovili možna odstopanja od zahtev ter priporočil. Na osnovi primerjave z zakonsko zahtevanimi vrednostmi smo določili gradbeno-tehnične ukrepe z namenom preprečevanja in obvladovanja čezmernega hrupa v bivalnih prostorih. Pri izračunu, meritvah in vrednotenju ustreznosti smo izhajali iz najstrožjih mejnih vrednosti, saj zahteve med seboj niso popolnoma usklajene. Rezultati izmerjenih vrednosti zunanjega nivoja hrupa za različne vire hrupa (LAFeq) in primerjava z mejnimi vrednostmi so pokazali, da je hrup cerkvenih zvonov (87,6 dB(A)) in hrup toplotne črpalke (59,9 dB(A)) presegal mejno vrednost območja 55 dB(A), hrup prometa (52,1 dB(A)) pa mejne vrednosti ni presegal. Rezultati izmerjenih vrednosti notranje ravni hrupa (LAFeq) za različne vire hrupa in primerjava z mejnimi vrednostmi je pokazala, da je v primeru hrupa cerkvenih zvonov (53,6 dB(A)) presežena mejna vrednost v notranjosti prostora podnevi (35 dB(A)), v primeru hrupa zaradi toplotne črpalke (26,5 dB(A)) mejna vrednost v notranjosti prostora ponoči (30 dB(A)) ni presežena, hrup prometa (44,0 dB(A)) pa presega mejno vrednost v notranjosti prostora ponoči (30 dB(A)) (čas zgodaj zjutraj). Pri določevanju zvočne izolirnosti smo upoštevali različne vire hrupa. Zvočno izolirnost v stari kamniti hiši smo določili na dva načina. Prvič smo upoštevali hrup zvonov in izračunali izolirnost 34,10 dB(A), ki ne zadošča mejni vrednosti 57,63 dB(A). Drugič smo v drugem prostoru iste hiše za izračun izolirnosti uporabili hrup zvočnika (90 dB(A)) in tako določili izolirnost 34,63 dB(A), ki tudi ne dosega mejne vrednosti 57,63 dB(A). V primeru hiše, obremenjene s hrupom toplotne črpalke, zvočna izolirnost (30,83 dB(A)) zadošča mejni vrednosti (27,33 dB(A)). Pri hiši, ki se nahaja ob prometni obvoznici, izolirnost (37,97 dB(A)), določena s pomočjo zvočnika (90 dB(A)), ne zadošča mejni vrednosti (63,97 dB(A)). Izolirnost smo določili tudi v dvostanovanjski hiši. Predelna stena med stanovanjema (51,32 dB(A)) ne zadošča mejni vrednosti (55,00 dB(A)). Z vidika celovitega preprečevanja in obvladovanja pred izpostavljenostjo hrupu v grajenem okolju bi bilo potrebno uskladiti zakonodajne zahteve, pri izračunih, meritvah ter vrednotenju ustreznosti pa izhajati iz najstrožjih mejnih vrednosti ravni hrupa. Using selected examples of residential buildings (different compositions of the building evelopes), we carried out a combination of measurements and calculations of the actual sound insulation values of the external separating elements. We dealt with the impact of traffic, the heat pump and the noise from the church bells. We compared the results of the measurements of the internal noise levels in protected building areas with the requirements and recommendations. We calculated the sound insulation of the facade using an equation and a software, and identified possible deviations from the requirements and recommendations. We have based the calculation, measurements and evaluation of compliance on the stringent limit values, as the requirements are not fully consistent with each other. The results of the measured values of external noise level for different noise sources (LAFeq) and the comparison with limit values indicated that the noise from the church bells (87.6 dB (A)) and the heat pump (59.9 dB (A)) exceeded the limit value of 55 dB(A), while the traffic noise (52.1 dB (A)) didn’t. The results of measured indoor noise level (LAFeq) for the different noise sources and the comparison with the limit values showed that in the case of church bell noise (53.6 dB (A)) the limit value (35 dB (A)) is exceeded, in the case of heat pump noise (26.5 dB (A)) limit value (30 dB (A)) is not exceeded, while traffic noise (44,0 dB (A)) exceeds the limit value (30 dB (A)) (early morning time). We determined the sound insulation of an old stone house in two ways. Firstly, we considered the noise of the bells and used an equation to calculate an isolation of 34.10 dB (A), which does not meet the equation’s limit of 57.63 dB (A). The second time, in another room of the same house, we used loudspeaker noise (90 dB(A)) to determine an insulating power of 34.63 dB (A), which does not meet the limit value given by the equation of 57.63 dB (A). In the case of a house, where we measured the heat pump noise, the sound insulation (30.83 dB (A)) determined by the equation meets the limit value (27.33 dB (A)). In the case of a house located on a bypass road, the insulation (37.97 dB (A)) determined by the equation and the loudspeaker (90 dB(A)) does not meet the limit value (63.97 dB (A)). The partition wall insulation in a semi-detached house (51.32 dB (A)), determined by the equation, does not meet the limit value (55.00 dB (A)). In terms of comprehensive prevention and control of noise exposure in the built environment, legislative requirements should be coordinated and the most stringent noise limit values should be used as a basis for calculations, measurements and assessment of adequacy.

Creep groan is a friction-induced, low-frequency vibration and noise phenomenon of a vehicleʼs brake system which is excited by a repeating stick-slip effect. Together with high influences of design and operational parameters, the non-linear stick-slip leads to an interesting bifurcation behaviour of creep groan. For objective rating procedures, detection and classification methods considering this bifurcation behaviour are necessary. Within this study, an approach based on acoustic emission is presented. The approach harnesses high-frequency acceleration contents that accompany creep groanʼs characteristic stick-slip transitions. Whereas low-frequency vibration contents below 500 Hz are mainly defined by the characteristics of the brake system and the suspension of the vehicle, vibrations in the high-frequency range above 10 kHz exhibit patterns of waveforms similar to the patterns of acoustic emission bursts. By applying non-overlapping high- and low-pass filters, a novel signal, enveloping these bursts, was created. This envelope bursts signal enables a precise detection and quantification of stick-slip transitions directly in time domain, and led to the development of a whole new set of vibration signal features. These nine signal features were used to feed the unsupervised classification algorithms k-means and Kohonenʼs self-organizing map, which delivered robust and meaningful results. Four different creep groan classes were detected, where each has shown to be linked to a specific creep groan manifestation: Low-frequency groan, high-frequency groan and two transition phenomena with two/three stick-slip events per cycle were found. Classification results and their linked mechanical behaviour suggest an interaction between two significant vibration patterns during creep groan, probably a longitudinal and a torsional displacement of the axle. Aside of deeper insights in creep groanʼs bifurcation behaviour, the presented study enables not only the identification of creep groan, but also the automatic classification of its manifestations in real-time, and therefore provides further possibilities for creep groan control methods.

Zaključna naloga obravnava različne metode za klasifikacijo zvočnih dogodkov hrupa v okolju. Poseben poudarek je namenjen metodi k-povprečij kot eni izmed najbolj ustreznih algoritmov za obdelavo nefonetskih ter neritmičnih zvočnih pojavov. Izvedene meritve pod nadzorovanimi pogoji služijo kot podpora analizi, v kateri smo se osredotočili na vlogo časovne konstante. Za ta namen smo ustvarili programsko kodo v kateri bo potekalo samostojno učenje računalnika na podlagi del pridobiljenihi podatkov. Cilj programa je na osnovi analize narejenih meritev ugotoviti vrednosti značilk za kateri bo izvršena klasifikacija, ter pokazati vpliv spremembe časovne konstante kot orodja za generaliziranje teh vrednosti samega rezultata klasificiranja. Merilne signale na mestu merjenja je zajemal mikrofon, z uporabo A/D pretvornika pa smo jih konvertirali v digitalno obliko, primerno za računsko analiziranje. Po ustrezni obdelavi v programskem jeziku “Python”, smo imeli možnost ugotviti, da časovna konstanta močno vpliva na nabor podatkov, ki se uporabljajo pri strojnem učenju, ter pri rezultatih kvalitete zaznavanja. Za prikaz rezultatov smo uporabljali t.i. matriko zmede ki predstavlja eno od metod za vizualiziranju uspešnosti klasifikatorja. The final thesis deals with different methods for classifying sound events of noise in the environment. Special emphasis is placed on the method of k-averages as one of the most suitable algorithms for processing non-phonetic and non rhythmic sound phenomena. The measurements performed under controlled conditions serve to support an analysis in which we focused on the role of the time constant. For this purpose, we have created program code in which the computer will learn independently on the basis of parts of the obtained data. The aim of the program is to determine the values of the characteristics for which the classification will be performed on the basis of the analysis of measurements, and to show the impact of changing the time constant as a tool for generalizing these values of the classification result. The measuring signals at the measuring point were captured by a microphone, and using an A / D converter, they were converted into a digital form suitable for computational analysis. After proper processing in the “Python” programming language, we were able to determine that the time constant strongly influences the data set used in machine learning and the perception quality results. To display the results, we used a so called confusion matrix that represents one of the methods for visualizing classifier performance.

Uvod: Otroci preživijo večino dneva v šoli, kjer se učijo novih znanj in spretnosti. Šole bi morale zagotavljati optimalno in zdravo okolje, v katerem bi se učenci dobro počutili in nadgrajevali svoje znanje. Namen: Namen magistrske naloge je izdelati metodološki pristop, temelječ na prenovi šolskih prostorov, ki bo izdelan na podlagi ocene stanja prostorov ter opreme in izmerjenih vrednosti mikroklime, CO2 ter hrupa v izbrani osnovni šoli. Metode dela: Uporabljena je kombinacija različnih metodoloških pristopov, in sicer sistematični pregled literature, samoocena stanja mikroklime s pomočjo namenskega vprašalnika, ocena stanja opazovanih okoljskih parametrov na podlagi meritev in izdelava algoritma. Rezultati: Z ogledom terena smo ugotovili, da zunanja kakovost zraka nima pomembnega vpliva na kakovost notranjega zraka v notranjosti osnovne šole. Ugotovili smo glavni problem slabe kakovosti notranjega zraka in povišanih koncentracij CO2. Problematično je odpiranje oken, ki ne omogočajo zadostnega prezračevanja. Visoke ravni hrupa so posledica slabe zvočne izoliranosti sten, tal in stropa, zaradi česar se zvočne vibracije širijo iz prostora v prostor. Ob ogledu smo odkrili tudi dotrajanost objekta osnovne šole, ki je potreben celovite prenove. Razprava in zaključek: Na podlagi razvitega metodološkega pristopa bodo prenove osnovnih šol v prihodnje bolj učinkovite in celostne, saj bo poleg arhitekturnega in gradbenega vidika upoštevan tudi zdravstveni vidik. Introduction: Children spend the majority of their day at school learning new skills. Schools should therefore provide an optimal and healthy environment making pupils feel comfortable to further upgrade their knowledge. Purpose: The purpose of the master's thesis is to develop a methodological approach based on the renovation of school premises. This approach will be based on the assessment of the premises and equipment's condition as well as the measured values of microclimate, CO2 and noise in the selected primary school. Methodology: A combination of different methodological approaches is used, including a systematic review of the literature, self-assessment of the microclimate using a purpose-made questionnaire, the observed environmental parameters state assessment (based on measurements) and algorithm creation. Results: While inspecting the premises, we found that the outdoor air quality does not significantly impact the indoor air quality inside the school. We managed to identify the main problem of poor indoor air quality and elevated CO2 concentrations. Windows not providing sufficient ventilation proved to be problematic. High noise values are caused by poor sound insulation of walls, floors and ceilings this causes sound vibrations to spread from classroom to classroom. During the inspection, we also discovered significant wear and tear of the primary school building, indicating the need for a complete renovation. Discussion and conclusion: Based on the developed methodological approach, the future primary schools' renovations will be more efficient and comprehensive. The health perspective will also be taken into account, in addition to the architectural and construction aspects.

V diplomskem delu proučujemo pojav hrupa med vzgojno-izobraževalnim delom v vrtcu in njegov vpliv na sluh vzgojiteljev. V raziskavo smo vključili 5 skupin otrok 1. starostnega obdobja in 5 skupin otrok 2. starostnega obdobja ter 15 vzgojiteljev Vrtca Kočevje. Na vzorcu smo preverjali, kolikšna jakost hrupa se pojavlja med različnimi dejavnostmi v skupinah 1. in 2. starostnega obdobja. Jakost hrupa smo merili med različnimi dejavnostmi – rutinske dejavnosti (zajtrk, malica, kosilo, počitek), vodene dejavnosti in spontana igra otrok, in sicer prvi teden v skupinah 1. starostnega obdobja, drugi teden pa v skupinah 2. starostnega obdobja. Ugotavljali smo tudi mnenje vzgojiteljev o hrupu med vzgojno-izobraževalnim delom v vrtcu in merili njihov sluh. Mnenje vzgojiteljev smo pridobili preko anketnega vprašalnika, meritve sluha smo izvedli z mobilno aplikacijo Fowler-Sabine. Z analizo smo ugotovili, da se najvišja jakost hrupa v skupinah otrok 1. starostnega obdobja pojavlja med vodeno dejavnostjo in znaša 81,20 dB(A), medtem ko pa se v skupinah otrok 2. starostnega obdobja pojavlja med spontano igro otrok in znaša 89,80 dB(A). Meritve jakosti hrupa so prav tako pokazale, da so otroci v skupinah 2. starostnega obdobja glasnejši tekom večine dejavnosti od otrok v skupinah 1. starostnega obdobja. Ugotovili smo tudi, da pri večini vzgojiteljev ne glede na delovno dobo in starost ni večjih odstopanj v poslabšanju sluha oziroma ima večina prag slušne občutljivosti do največ 13 dB, kar pomeni, da imajo po klasifikaciji naglušnosti normalen sluh. The diploma thesis examines the occurrence of noise during educational work in kindergarten, and its impact on preschool teachers' hearing. The study involved 5 groups of children from the 1st age bracket and 5 groups of children from the 2nd age bracket, and 15 teachers at the kindergarten Vrtec Kočevje. The sample was used to examine the noise level that occurs during various activities in groups of the 1st and 2nd age bracket. The noise level was measured during different activities – routine activities (breakfast, snack, lunch, rest), guided activities, and the children's spontaneous play, namely during the first week in groups of the 1st age bracket, and during the following week in groups of the 2nd age bracket. The study also aimed to determine what teachers think about noise during educational work in kindergarten, and their hearing was tested. The teachers' opinions were obtained by means of a survey questionnaire, while the hearing tests were carried out using the Fowler-Sabine mobile application. The analysis has determined that the highest noise level in groups of children from the 1st age bracket occurs during guided activities and amounts to 81.20 dB(A), while in groups of children from the 2nd age bracket it occurs during the children's spontaneous play and amounts to 89.80 dB(A). The noise level measurements have also shown that children from the 2nd age bracket groups are louder during most activities than the children from the 1st age bracket groups. It has also been established that there are no major deviations in hearing deterioration in most preschool teachers based on their length of service and age most of them have a hearing threshold of up to 13 dB, which means that they have normal hearing according to the hearing loss classification.

V diplomski nalogi je predstavljen delovni proces v betonarni Pristava, podjetja GIC gradnje d.o.o. Večja pozornost je posvečena prepoznavanju nevarnosti in tveganj z vidika varnosti in zdravja pri delu, pri tem pa smo se še posebej osredotočili na hrup in opravili tudi okvirne meritve hrupa med delovanjem betonarne. Prav tako smo obravnavali osebno varovalno opremo in ostale načine varovanja, delavcev pred nevarnostmi in tveganji pri delu v betonarni. In this work we discuss the work process in the concrete plant Pristava, GIC gradnje d.o.o. The focus is on identifying hazards and risk factors at work, especially those connected to the noise. Some approximate measurements of the noise were also made in the concrete plant during the operational hours. We put some attention also to personal protective equipment and other types of protection, used by workers to protect themselves from the working hazards and risks in the concrete plant.

V magistrskem delu je predstavljen projekt razvoja impedančne cevi za merjenje koeficienta absorpcije zvoka z uporabo prenosne funkcije. Cev je bila razvita s pomočjo standarda ISO 10534-2 za merjenje frekvenčnega območja med 250 in 5000 Hz. Za verifikacijo rezultatov je bila narejena primerjava z metodo, ki je popisana v ISO 10534-1. Za izdelavo cevi so bili uporabljeni cenejši in dostopnejši materiali, ki so bili obdelani s klasičnimi postopki obdelave, prav tako pa so bili nekateri elementi cevi izdelani s pomočjo aditivne tehnologije, ki se v zadnjem obdobju močno razvija. Da lahko dosežemo natančne meritve v tako širokem frekvenčnem spektru, je bila metoda opisana v standardu prilagojena za uporabo s tremi mikrofoni. Za potrebe meritev je bila razvita programska koda za kalibracijo mikrofonov in za izračun vrednosti koeficienta absorpcije zvoka na podlagi treh različnih kombinacij postavitve mikrofonov. Meritve so bile izvedene na desetih različnih poroznih materialih različne debeline. Opazovali smo spreminjanje koeficienta absorpcije zvoka ob dodajanju večjega števila slojev materiala. Rezultati so pokazali, da nam razvita metoda omogoča natančne meritve in hitrejšo menjavo vzorcev. Za določanje upornosti zračnega pretoka ?, ki predstavlja enega ključnih vhodnih podatkov za modeliranje zvoka v prostoru, je bila razvita programska koda, ki temelji na empiričnem modelu Delany – Bazley. This paper presents a project for the development of an impedance tube for measuring the sound absorption coefficient using a transfer function. The tube was developed using the ISO 10534-2 standard to measure the frequency range between 250 and 5000 Hz. To verify the results, a comparison was made with the method described in ISO 10534-1. To make the tube, cheaper and more accessible materials were used, which were processed by classical processing methods. Some elements of the tube were also made with the help of additive technology, which has been developing rapidly in recent times. To be able to achieve accurate measurements in such a wide frequency spectrum, the method described in the standard has been adapted for use with three microphones. For the purposes of the measurements, a software code was developed for the calibration of the microphones and for the calculation of the value of the sound absorption coefficient on the basis of three different combinations of microphone placement. Measurements were performed on ten different porous materials of different thickness. A change in the sound absorption coefficient has been observed with the addition of a larger number of layers of material. The results show that the developed method allows us to make accurate measurements and change samples faster. To determine the flow resistivity σ, a program code based on the empirical Delany - Bazley model was developed.

Hrup je pri načrtovanju mest prihodnosti velik dejavnik, saj se vedno bolj zavedamo, kakšen vpliv ima na zdravje in kvaliteto življenja. Načrtovalci javnih površin tako vedno več odločitev sprejemajo z namenom obvladovanja hrupa. Trenutne rešitve za pridobivanje podatkov o hrupu so drage in zahtevajo veliko načrtovanja, zato se jih velikokrat preskoči. V sklopu diplomske naloge smo načrtovali in razvili cenovno dostopen sistem, ki omogoča hitro in enostavno opazovanje hrupa na poljubno velikih območjih s poljubnim številom senzorjev. Razvili smo cenovno dostopne merilne enote, odprtokodno platformo za upravljanje zaznavanja in shranjevanje podatkov ter spletne in programske vmesnike za učinkovito podatkovno analizo. Uporabnost sistema smo preizkusili in potrdili v več pilotnih študijah. Noise management is an ever-growing part of designing future urban landscapes. We’re becoming more aware of the effects of noise pollution on health and quality of life. With that, the pressure on city planners to manage noise more efficiently is becoming more prominent. Current solutions for researching noise are often too expensive and time-consuming and, regarding noise, urban planning relies on intuition rather than on the data. In the thesis, we design and implement a cost-effective, scalable, flexible urban noise analysis system. We have developed affordable measuring units, a user interface, an open-source server for data storage, and a widget for efficient data analysis. We tested and confirmed the utility of the system in several pilot studies.

V tem delu je predstavljena eksperimentalna analiza akustičnega in vibracijskega odziva EC motorjev, pri katerih se je pojavila želja po zvišanju vrtljajev. Elektromotorji so uporabljeni v mnogo napravah, v katerih lahko prisotnost hrupa in povišanih vibracij negativno vpliva na njihovo delovanje. Vibracije povzročajo obrabo in zmanjšujejo življenjsko dobo izdelkov, hrup pa negativno vpliva na človeško počutje in zdravje. Na EC motorjih so bile pomerjene vibracije in hrup, na podlagi dobljenih meritev pa je bila opravljena analiza, s katero smo preverili vzroke za tak vibracijski in akustičen odziv. The work presents experimental analysis of acoustic and vibration response of EC motors in which there was a desire to increase the speed. Electric motors are used in many devices, where increased vibrations and noise can adversely affect their operation. Vibrations causes wear and reduce product lifetime while noise negatively affects human well-being and health. Vibration and noise were measured on EC motors, and based on the obtained measurements, an analysis was performed to verify the causes of such vibration and acoustic response.

Zaključno delo se ukvarja z aerodinamičnim vzbujanjem konzolno vpete tanke plošče ter razlikovanjem med vibracijsko in aerodinamično generiranim hrupom. Izveden je bil eksperiment, v katerem smo s počasnim zračnim curkom vzbujali konzolno vpeto tanko ploščo, ter opazovali odziv njenih vibracij v odvisnosti od frekvence. Razloženi so posamezni vplivi na vibracijski odziv tanke plošče. The thesis deals with an aerodynamicly excited simply supported thin plate and the distinction between vibration generated and aerodynamicly generated noise. An experiment was carried out in which we used a slow air jet to excite a cantilever-mounted thin plate and observed the response of its vibrations as a function of frequency. The individual effects on the vibration response of a thin plate are explained.

Zaključna naloga obravnava vpliv različnih parametrov zvočnih signalov na značilko zvočnih virov, imenovano dominantnost. Obravnavana značilka vpeljuje skalarno vrednost za popis prevladujočega zvočnega vira. Analiza vpliva izbranih akustičnih parametrov je izvedena na osnovi meritev pod nadzorovanimi pogoji v gluhi sobi, kjer je ustrezno postavljen merilni sistem omogočal izvedbo meritev s spreminjanjem ustreznih lastnosti zvočnih virov glede na željene pogoje. Namen naloge je na osnovi analize izvršenih meritev ugotoviti osnovne karakteristike odvisnosti značilke dominantnosti od frekvenčnega spektra, medsebojne lokacije in ravni zvočnega tlaka zvočnih virov na mestu imisije ter rezultate podati na vizualno preprost in razumljiv način. Merilne signale na mestu merjenja je zajemala mikrofonska antena, sestavljena iz štirih omnidirekcionalnih mikrofonov, ter jih preko analogno-digitalne pretvorbe na večkanalni zvočni kartici pretvorila v digitalno obliko, primerno za nadaljnjo računalniško analizo. V zaključni nalogi se primerjajo rezultati usmerjenosti enega zvočnega vira z rezultati usmerjenosti dveh zvočnih virov z različnimi lastnostmi, kar omogoča generalizacijo na primere več zvočnih virov v spremenljivih kombinacijah, kot se pojavljajo pri meritvah v realnem okolju. Po opravljenih meritvah smo potrdili smiselnost vpeljave značilke za analizo meritev hrupa v naravnem in življenjskem okolju. Ugotovili smo, da značilka dominantnosti na preprost način omogoča natančnejšo interpretacijo in razločevanje zvočnih virov pri meritvah hrupa v realnem okolju in omogoča nove možnosti na področju razvoja algoritmov za avtomatizacijo in klasifikacijo zvočnih virov v prihodnosti. The thesis contains the analysis of different parameters of sound signals from noise sources on noise feature called dominance. The considered feature introduces a scalar value to determine the degree of dominance of sound sources on the total noise level. The analysis is performed on the basis of measurements under controlled conditions in an anechoic chamber. A properly placed measurement system allows measurements to be made by changing the corresponding characteristics of the sound sources according to the desired conditions. The aim of the task is to determine the basic characteristic of the dependence of the dominance curve on the frequency spectrum, location and sound pressure level of the sound sources at the point of immission and to present the results in a visually simple and understandable way. The measurement signals at the measurement location were recorded with a microphone array consisting of four omnidirectional microphones and converted into a digital form suitable for further computer analysis by means of an analog-to-digital conversion of the sound card. The work deals with the case of one and two simultaneous sound sources with different characteristics, which allows a generalization to examples of more sound sources in variable combinations that occur in real field measurements. After the measurements we confirmed the introduction of the feature into the analysis of noise measurements. We found that the dominance allows in a simple way a more accurate interpretation and differentiation of sound sources in noise measurements in the real environment and offers new possibilities in the development of algorithms for the automation and classification of sound sources in the future.

Razvoj in modernizacijo družbe spremlja tudi povečanje hrupa iz različnih virov, med katerimi je najpogostejši in najbolj zaskrbljujoč hrup iz cestnega prometa. Njegovo čezmerno povečevanje ne povzroča zgolj razvrednotenja bivalnega okolja, temveč tudi pomembno vpliva na zdravje ljudi. Negativni učinki so predvsem odvisni od jakosti in trajanja izpostavljenosti. V ta namen smo izvedli raziskavo o vplivu protihrupnih ograj na obremenjenost s hrupom na avtocestnem odseku A1 Brezovica – Vrhnika. Za namen ocenjevanja njihovega vpliva so bile izvedene meritve ob obeh voznih smereh avtoceste pri različnih načinih postavitve protihrupnih ograj. Meritve so se izvajale na merilnih točkah različnih razdalj, in sicer med 10 in 500 m oddaljenosti od avtoceste. Njihova analiza je pokazala, da protihrupne ograje opazno vplivajo na zmanjšanje hrupa do oddaljenosti 150 m od avtoceste. V povprečju so hrup pri razdalji 10 m zmanjšale za 13 dBA, pri 50 m za 8,9 dBA, pri 100 m za 3,8 dBA in pri 150 m za 1,1 dBA. Pri 200 m je bil hrup zmanjšan le še za 0,9 dBA. Med 200 in 500 m je bil vpliv protihrupnih ograj enak nič ali celo rahlo negativen. Na posameznih merilnih točkah so bili zaznani tudi zvočni odboji, ki jih povzročajo protihrupne ograje. Zaradi relativno slabe učinkovitosti slednjih je torej izredno priporočljivo zmanjševanje hrupa na samem izvoru. The development and modernization of society is also accompanied by an increase in noise from various sources, among which the most common and worrying is noise from road traffic. Its excessive increase not only devalues the living environment, but also has a significant impact on human health. Negative effects mainly depend on the intensity and duration of exposure. For this purpose, we conducted a study on the impact of noise barriers on noise pollution on the motorway section A1 Brezovica - Vrhnika. For the purpose of assessing their impact, we took measurements along both driving directions of the motorway at different layouts of the noise barriers. Measurements were performed at measuring points of different distances, namely between 10 and 500 m distance from the motorway. The analysis showed that noise barriers have a noticeable effect on reducing noise up to a distance of 150 m from the motorway. On average, they reduced noise at a distance of 10 m by 13 dBA, at 50 m by 8.9 dBA, at 100 m by 3.8 dBA and at 150 m by 1.1 dBA. At 200 m, the noise was reduced by only 0.9 dBA. Between 200 and 500 m, the impact of noise barriers was zero or even slightly negative. There were also detected some sound reflections caused by noise barriers at individual measuring points. Due to the relatively poor efficiency of the latter, it is therefore highly recommended to reduce the noise at its source.

Ergonomija je veda, ki je bistvenega pomena za človeka in njegovo doživljanje delovnega mesta in domačega okolja. Znanje ergonomije nam omogoča, da prepoznamo obremenitev in delo prilagodimo delavcu. Za ureditev delovnih mest moramo upoštevati načela ergonomije, ter številne ergonomske metode. Na delovnem mestu imamo veliko število obremenitev in sicer toplotnih, vidnih, slušnih, obremenitev zaradi stika z aerosoli in plini ter parami tudi obremenitve zaradi monotonije in stresa. V diplomski nalogi je poudarek na ergonomski analizi delovnega mesta po metodi OWAS ter opravljenih meritev hrupa in osvetlitve. Meritve hrupa in osvetljenosti so opravljene v skladu s slovensko zakonodajo in standardizacijo. Glede na opravljeno analizo delovnega mesta so predlagani tudi ukrepi za izboljšanje, ki bi jih podjetje lahko uvedlo, da bi se obremenitve na delavca zmanjšale. Ergonomics is a science that is essential to a person in their work experience. Knowledge of ergonomics allows us to identify the load in the work to adapt workers. In order to arrange workplace it is important to check the principle of ergonomics and ergonomic methods. In the workplace we have a large number of loads in thermal, visible, auditory, contact with aerosols in gases and vapour also loads due to monotony in stress. The diploma thesis focuses on ergonomic analyzes of workplaces according to the OWAS method and measurements of noise in lighting. Measurements of noise in illumination are in accordance with Slovenian law and standardization. According to analyzes of the workplace there are prepositions for improvement, which the company could use in order to reduce the load workload.

V delu je predstavljena uporaba metamaterialov za namene zniževanja hrupa na področju akustike in strukturne dinamike. Preko obravnave osnovnega gradnika oz. bazne celice, ki sestoji iz osnovne strukture in resonatorja, so obravnavane lastnosti neskončnega 2D periodičnega metamateriala. Ob pravilni zasnovi je le-ta sposoben formirati pasovno zavrnitveni filter (PZF) v željenem frekvenčnem območju, kjer prosto širjenje valovanj ni dovoljeno. PZF smo identificirali s pomočjo disperzijskih krivulj, ki smo jih izračunali z uporabo direktnega in inverznega pristopa. Preračunan koncept metamateriala se je kasneje tudi izdelal s pomočjo FFF tehnike 3D tiskanja. Izračunano in izmerjeno frekvenčno območje PZF se zadovoljivo ujemata. Ob masnem razmerju resonatorja in osnovne strukture 0.1 je metamaterial v območju PZF zmožen hrup znižati za 4 dB več kot le njegova osnovna struktura ekvivalentne mase. This thesis describes metamaterials for noise reduction in acoustics and structural dynamics. Through analysis of the unit cell of a 2D periodic metamaterial consisting of the base structure and carefully placed resonating structures, the dynamic characteristics of the whole structure were obtained via dispersion curves. Appropriately sized metamaterials can exhibit band gaps in which free wave propagation is not allowed. Band gaps were identified via dispersion curves which were calculated using a direct and inverse approach. Metamaterial design was also manufactured using FFF 3D printing technique. A good agreement between calculated and measured band gap frequency region was identified. 4 dB stronger noise reduction was measured by metamaterial with a mass ratio of 0.1 between resonators and base structure compared to only its base structure with equivalent mass.

Leta 2013 je bila narejena raziskava o vplivu delovnih razmer na obremenitve strojnikov zgibnega polprikoličarja z ropotom. Celodnevne meritve časa, učinkov in jakosti ropota so potekale v Italiji in Sloveniji. Raziskava je zajela 5 zgibnih polprikoličarjev ter kategorije spravila ravno in navzdol. Uporabljen je bil mednarodni standard SIST EN ISO 9612:2009, za časovno študijo pa IUFRO klasifikacija. Največja jakost ropota v produktivnem času (PW) je bila izmerjena v času prazne in polne vožnje. 8-urna obremenitev (LAex8h) brez vpliva radia in odprte kabine je znašala 77,9 dB(A), z vplivom radia in odprte kabine pa 82,6 dB(A) in je presegla spodnjo opozorilno mejo Evropske direktive 2003/10/EC ter Pravilnika o varovanju delavcev pred tveganji zaradi izpostavljenosti hrupu pri delu (2006). Manjša kot je odprtost gozdov s primarnimi prometnicami (ali daljša kot je razdalja polne vožnje) ter večje kot je število kosov v bremenu, večje so obremenitve z ropotom. Značilno povišan ropot je bil ugotovljen tudi pri poslušanju radia (3,6 dB(A)) oz. pri odprti kabini (11,9 dB(A)). Strojniki bi morali nositi osebno varovalno opremo za zaščito sluha (glušnike) ali ugašati motor stroja kadar se nahajajo izven zaščitne kabine in v odprti kabini. Glede na statistično značilne razlike v obremenitvah je bila predlagana spremenjena členitev delovnega časa na operacije in prijeme. The research about the influence of working conditions on operator's noise exposure at forwarding was made in 2013. Whole day time and noise measurements were made in Italy and Slovenia. 5 forwarders were included. Category of forwarding was down and flat. International standard SIST EN ISO 9612:2009 and IUFRO classification of working operations were used. Full drive distance, average piece and net volume time structure showed increment in empty and full drive due to reduction in loading and unloading, while time structure for number of pieces showed increment in loading and unloading due to reduction in empty and full drive. The highest noise load in productive time (PW) was measured during empty and full drive. 8-hour noise exposure (LAex8h) without the influence of radio and open cabin was 77,9 dB(A) and with the influence of radio and open cabin 82,6 dB(A), so it exceeded lower warning limit stated in European directive 2003/10/EC and Slovenian Regulations on the Protection of Workers from Risks Related to Noise Exposure at Work (2006). The lower the openness of forests with primary roads (or the longer the distance of travel) and the bigger the number of pieces, the higher the noise load was. Significantly higher noise load was established while radio was turned on (3,6 dB(A)) and at open cabin (11,9 dB(A)). Forwarder drivers should turn off the machine or wear personal ear protection gear (ear muffs) while being outside the cabin or being inside the open cabin. On the base of statistical analysis new classification of working operations and approaches was proposed.

V magistrskem delu obravnavamo karakterizacijo in razpoznavanje zvokov ventilov grelnih sistemov. Med seboj primerjamo hrup ventilov najrazličnejših dimenzij, funkcij in geometrije. Na podlagi podatkovne baze zvočnih posnetkov oblikujemo primerne kategorije hrupa. S pomočjo statistične analize zvočnih signalov, ki jih izmerimo na ventilih, izpeljemo statistične značilke v časovni in frekvenčni domeni. Iščemo načine, kako na podlagi značilk zvočne signale pravilno razvrstiti v kategorije. S pomočjo odločitvenih pragov naredimo več razvrstitvenih modelov v obliki odločitvenih dreves. Zaporedje vozlišč in vrednosti odločitvenih pragov generiramo ročno in numerično. Pri tem so naše zahteve enostavno odločitveno drevo, majhna skupna povprečna ocena napake pri razvrstitvi in dobro ločevanje pojavov piskanja in kavitiranja. Glede na to ugotovimo, da sta za uporabo v praksi najbolj primerna dva modela. Prvo je odločitveno drevo razvejenosti 11, ki ima najmanjšo skupno povprečno napako pri razvrstitvi. Drugo je odločitveno drevo, katerega zgradba je določena ročno, odločitveni pragovi pa numerično. To drevo najbolje loči pojava piskanje in kavitiranje. In the master's thesis we explore the problem of characterization and recognition of sounds on the valves of heating systems. We compare noise on the valves of various dimensions, functions and geometry. Based on the data base of soundtracks, suitable noise categories are formed. We extract statistical features in the time and frequency domains, with the help of statistical analysis of sound signals measured on valves. Based on the extracted features, we propose means to classify the sound signals into proper categories. With the help of decision thresholds we develop several classifying models formulated as decision trees. The sequence of nodes and value of decision thresholds are generated manually and numerically. Our requirements are a simple decision tree, low classification loss and a good separation of the phenomena of squealing and cavitation. According to our requirements we choose two models that are most suitable for practical use. First is decision tree with branching level 11, which has the lowest classification loss. Second is decision tree with manually defined structure and numerically defined decision thresholds. The latter best distinguishes phenomena of squealing and cavitating.

Uvod: V današnjem času preživimo okoli 90 % svojega časa v zaprtih prostorih, kjer smo izpostavljeni raznim nenaravnim zvokom. Hrup je vsak neželen zvok, ki negativno vpliva na počutje in zdravje ljudi ter škodljivo vpliva na okolje. Namen: Pridobiti podatke, kolikšnim ravnem hrupa so izpostavljeni zaposleni pri opravljanju svojega dela na opazovani Osnovni šoli. Metode dela: Osredotočili smo se na zaposlene, otroci v raziskavo niso bili vključeni. Naloga je razdeljena na šest delov: samoocena hrupa zaposlenih (vprašanja o izpostavljenosti in zdravstvenih težavah zaradi izpostavljenosti hrupu), ocena stanja stavbe in njene okolice, (pregled okolice stavbe, velikost in orientacija prostorov, izvedba in materiali notranje opreme), meritve hrupa (v skladu s SIST ISO 9612:2009, z merilnim inštrumentom Brüel & Kjar 2260 Investigator. Meritve so potekale v ponedeljek, sredo in petek v učilnicah, avli, telovadnici, jedilnici in garderobi. Merili smo ekvivalentno raven hrupa, konično raven hrupa ter ocenjeno raven hrupa z impulzivno korekcijo - LAI,Te), namestitev elektorskega ušesa (namestitev v jedilnici za poskusno obdobje), pregled učinkovitosti uporabe elektronskega ušesa in korektivni ukrepi (organizacijski, pedagoški, gradbenotehnični). Rezultati: Po pregledu okolice šole smo spoznali, da le-ta nima vpliva na notranji hrup. Z analizo prostorov smo ugotovili, da prevladujejo materiali: les, beton in opeka. Popis opreme je pokazal, da je le-ta iz kovine in lesa (vsi uporabljeni materiali bolj odbijajo zvok kot absorbirajo). Najbolj hrupen dan v tednu je ponedeljek. Najvišje LAI,Te (povprečno 87,67 dB) so v avli šole, kar presega predpisano mejno vrednot 87 dB. Zgornja opozorilna vrednost 85 dB je presežena v jedilnici v času kosila in malice (86 dB). Spodnja opozorilna vrednost 80 dB je presežena v garderobi (82,9 dB). Uporaba elektronskega ušesa in izveden organizacijski ukrep je občutno zmanjšal hrup v jedilnici. Razprava in zaključek: Pripravili smo enostaven obrazec za celostno oceno stanja stavbe in splošen spisek najbolj pogostih korektivnih ukrepov za vse osnovne šole, ki imajo težave s hrupom, predvsem z zdravjem uporabnikov stavbe ter kakovostnim izvajanjem izobraževalne dejavnosti. Introduction: Nowadays, we spend about 90% of our time inside, where we are exposed to various unnatural sounds. Noise is each unwanted sound which has a negative impact on our feeling and health and has an adverse effect on the environment. Purpose: To obtain data about the levels of noise that the employees at the primary school concerned are exposed to. Methods of work: The focus was on the employees while children were not the subject of the research. The thesis is divided in six parts: self-assessment of noise by employees (questions about the exposure and health issues resulting from the exposure to noise), a comprehensive assessment of the condition of the building and its surroundings (examination of the surrounding of the building, the size and orientation of rooms, interior equipment layout and materials), measuring the noise (in accordance with SIST ISO 9612:2009, measuring instrument Brüel & Kjær 2260 Investigator. Measurements were done on Monday, Wednesday and Friday, in classrooms, lobby, gym, dining room and changing rooms. The following were measured: equivalent noise level, peak noise level and estimated noise level with impulsive correction - LAI,Te), installing an electronic ear (installing in the dining room for a trial period of time), review of efficiency of an electronic ear and corrective measures (organisational, teaching and construction and technical measures). Results: Examination of the surrounding of the school showed that it does not affect the noise inside. Analysis of the premises showed that the prevailing materials are wood, concrete and bricks, while the inventory of equipment included metal and wood (all the materials used bounce rather than absorb noise). The noisiest day in the week was Monday. The highest LAI,Te (average 87.67 dB) were recorded in the school lobby, which exceeds the limit value of 87 dB. The upper exposure value of 85 dB is exceeded in the dining room during breakfast and lunch (86 dB). The bottom exposure value of 80 dB is exceeded in the changing room (82.9 dB). Use of an electronic ear and an organisational measure implemented resulted in a substantially decreased noise in the dining room. Discussion and conclusion: A simple form for a comprehensive assessment of the condition of the building and a list of the most common corrective measures have been prepared, which can be applied by all primary schools which have problems with noise, mainly with the health of the users of the building and consequently with carrying out the educational activity.

Gospodinjski aparati in naprave nam olajšujejo vsakodnevna opravila, vendar pri tem proizvajajo določeno raven nezaželenega hrupa, ki zmanjšuje udobje v prostoru in slabša kvaliteto bivanja, zato želimo hrup zmanjšati na najmanjšo možno raven. V tem zaključnem delu smo se osredotočili na zmanjšanje zvočne moči sušilnega stroja. Zvočno moč lahko zmanjšamo na več načinov, mi pa smo se odločili, da bomo za zmanjšanje uporabili zvočno absorpcijski material, v našem primeru smo izbrali poliuretansko peno dveh različnih debelin. Najprej smo opravili meritev zvočne moči sušilnega stroja brez dodanega absorpcijskega materiala, nato pa smo na sušilni stroj na predhodno določene lokacije namestili poliuretansko peno in ponovno opravili meritve zvočne moči. Za končni ukrep smo izbrali absorpcijski material na desni stranici in na režah zadnje stranice sušilnega stroja. S tem ukrepom smo porabili najmanj poliuretanske pene, hkrati pa smo zvočno moč sušilnega stroja zmanjšali za 3,4 dB. Home appliances and apparatus help us perform our daily tasks however, they also produce a certain level of unwanted noise that reduces the comfort in the room and our quality of life. Our aim is to scale down the noise levels to a minimum. The paper focuses on reducing the sound power of a laundry dryer. Sound power can be reduced in various ways, and we decided to use sound-absorbing material, in our case the polyurethane foam in two varying thicknesses. First, we measured the sound power of the laundry dryer without the absorbing material. Next, we covered some predetermined places of the laundry dryer with the polyurethane foam and once again measured the sound power. Lastly, we selected the absorbing material on the right side and on the gaps of the last side of the laundry dryer. This way we used less polyurethane foam and at the same time reduced the sound power of the laundry dryer by 3,4 dB.

V diplomskem delu smo se seznanili z zvokom in sicer z njegovim nastankom, širjenjem ter vrstami zvoka. Stranski produkt zvoka je hrup, ki predstavlja njegovo neželeno komponento in čigar negativen vpliv na človeka v vsakdanjem življenju želimo minimalizirati. Dolgotrajna izpostavljenost hrupu lahko povzroči različna obolenja, vpliva lahko na sluh, prav tako pa povzroča tudi različne bolezni živčevja in srčno žilne bolezni. V nadaljevanju diplomskega dela smo se osredotočili na hrup na delovnem mestu. Zanimalo nas je, ali je raven hrupa, ki so ji delavci dnevno izpostavljeni v zakonodajnih okvirih, ali presega mejo dovoljene vrednosti. Hrup smo merili v lesno predelovalni industriji na treh različnih delovnih mestih. S terčno analizo smo hrup podrobneje analizirali skozi celoten frekvenčni spekter človeškega sluha. Rezultati meritev in frekvenčna analiza sta nam bila v pomoč pri nadaljnjih predlogih za sanacijo hrupa na delovnih mestih, ki so bili predmet raziskav. In this work, we got acquainted with sound in general, namely with its creation, propagation, and its many types. The by-product of sound is noise, which is characterized as an unwanted and harmful component of sound and by that our goal is to limit human exposure to it by as much as possible. Long-term exposure to noise can impact our health ability, hurt our psychological wellbeing and be the cause of many illnesses, including neurological and cardiovascular diseases. Later in work, we shifted our focus to the level of noise in the working environment. The goal was to determine if the level of noise that the workers are exposed to daily is within the legislative framework. The noise was measured in a typical woodworking facility at three different locations within the operating environment. The measured values were interpreted in detail using third octave-band analysis along with the complete frequency spectrum of human hearing. The obtained results of the measurements and analysis were used to conduct additional recommendations for the control of noise in the working environments, that were subjected to research.

Hrup transformatorja, ki izvira iz vibracij navitij, je močno odvisen od poteka magnetnega polja na njihovem mestu. S spreminjanjem geometrije navitij je mogoče spremeniti potek magnetnega polja in posledično vplivati na hrup transformatorja. Vpliv spremembe geometrije na vibracije navitij je mogoče analizirati z elektromagnetnim izračunom, ki mu sledi strukturni numerični model. Za potrebe optimizacije geometrije smo razvili poenostavljen numeričen izračun hrupa, ki deluje veliko hitreje od klasičnih metod izračunov, in ga uporabili v optimizacijski zanki za optimizacijo geometrije. Transformer noise that results from the winding vibrations strongly depends on the surrounding magnetic field distribution. By changing the geometry of the windings, one can change the magnetic field distribution and affect the transformer noise. The effect of winding geometry change on vibrations can be analyzed with electromagnetic calculation, followed by a structural numerical model. We have developed a simplified numerical noise calculation method for the purpose of geometry optimization, that works much faster than conventional numerical methods, and used it in a geometry optimization loop.

Kot štipendist podjetja Domel in študent fakultete za strojništvo, sem se odločil združiti probleme podjetja z znanjem, pridobljenim na fakulteti. Rezultat pa je rešitev, predstavljena v tem diplomskem delu. Zaradi zahtev trga se je podjetje Domel odločilo razviti novo različico puhala. Za nastanek povsem novega izdelka sem uporabil le dva nova elementa sestava- okrov in pokrov. Konstruiral sem ju z mislijo na funkcionalnost, možnost izdelave, geometrijske omejitve že obstoječih komponent in zahteve trga. Ideja je prerasla v model, ta pa v konkretni izdelek. Izdelek sem tudi testiral s standardnim testom pretočnosti in tlačnih razlik ter testom hrupnosti. Rezultate sem ovrednotil in hkrati ugotavljal, če se izdelek splača izdelovati serijsko. As a scholarship holder of a Domel company and a student of faculty of mechanical engineering I have decided to combine problems of company with knowledge gained at faculty. Results are shown in this diploma. Since the market showed its interest, the Domel company has decided to develop new type of a blower. For construction of whole new type of blower I have only used 2 parts that differed from the previous assembley- cowling and cover. I designed them with thought on functionality, feasibility, geometrical and dimensional restrictions and market demands. The idea grew into model which developed into product. I tested assembly with standard flowing and pressure tests and noise test. I evaluated the results and determined whether the item production does or does not pay of.

Varno delo in delovno okolje sta dandanes pomembni okoliščini v vseh organizacijah. Varne in zdrave delovne razmere pa so zelo pomembne tako za delavce kot za delodajalce, saj lahko vplivajo na posel in družbo kot celoto. Namen varnosti in zdravja pri delu predstavljajo predvsem izogibanje in obvladovanje tveganj, prilagajanje dela posamezniku z ustreznim oblikovanjem delovnega okolja, izbira varne delovne opreme itd. Namen diplomskega dela je proučiti in predstaviti, kako pomembna sta varnost in zdravje pri delu ter na kakšen način lahko zagotovimo varno delovno okolje. Z metodo anketiranja pa je predstavljena raziskava na področju varnosti in zdravja pri delu v izbrani organizaciji. Rezultati raziskave kažejo, da večino sodelujočih v raziskavi oz. zaposlenih v izbrani organizaciji moti hrup. Hrup moti njihovo koncentracijo, vpliva na povečanje stresa, na tveganje za nastanek nezgod in na splošno vpliva na njihovo zdravje. Tudi visoke temperature vplivajo na varno delo in predstavljajo potencialno tveganje za zdravje zaposlenih. Ugotovljeno je torej, da hrup in visoka temperatura vplivata na zdravje in varno delo zaposlenih ter da zaposleni nimajo najbolje urejenih delovnih razmer. Predlaga se, da organizacija poskrbi za varnejše delo in delovno okolje ter ustrezno uredi delovne razmere. Torej da zmanjša hrup in visoke temperature na način, ki ne bi ogrozil proizvodnje, vseeno pa bi olajšal delo in zmanjšal negativen vpliv na zdravje zaposlenih. Prav tako bi morali več pozornosti nameniti izobraževanju o varnosti in zdravju pri delu ter poskrbeti za še bolj ustrezno varovalno opremo, saj bi se tako zmanjšalo število poškodb pri delu. Safe work and working environment are nowadays important in all organizations. Safe and healthy working conditions are of great importance to employees as well as employers, as they can affect business and society as a whole. The purpose of safety and health at work is mainly avoiding and managing risks, adjusting work to individuals by designing the appropriate working environment, selecting safe work equipment, etc. The purpose of the paper is to examine and present the importance of safety and health at work and to show how a safe working environment can be achieved. The paper also includes a survey on the topic of safety and health at work in a Slovenian company. The results of the research show that noise at workplace bothers most of the participants of the survey, the employees of a specific Slovene company. The noise disrupts their concentration, elevates employees’ stress levels, increases the risk of accidents and affects their health in general. High temperatures also affect safe work and present a potential risk to the health of the employees. The research determined that noise and high temperatures affect their health and safety and that the employees do not work in the best working conditions. The company should ensure a safer working environment in order to reduce noise and high temperatures in such a way that would not endanger production, but would make work easier and reduce the negative impact on employee health. It should also devote more attention to education on safety and health at work, and provide a more appropriate protective equipment in order to reduce the number of injuries at work.

Namen magistrskega dela je izvedba optimizacije delovanja hladilno-zamrzovalnega aparata z uporabo metode diferenčne evolucije. Optimizirani parametri so hrup, poraba energije, temperaturni gradient in hladilna ter zamrzovalna kapaciteta. Predlagana metoda omogoča iskanje optimalnih vrtljajev kompresorja in ventilatorja hladilno-zamrzovalnega aparata. Rezultat magistrskega dela tako predstavljajo navedeni optimalni vrtljaji za različne profile delovanja hladilno-zamrzovalnega aparata in napotki, kdaj naj aparat deluje v katerem profilu. The purpose of this masters thesis is the performance optimization of the fridge-freezer using the differential evolution method. Optimized parameters are audible noise, energy consumption, temperature gradient and cooling/freezing capacity. With the proposed method we are able to search for an optimal fan and compressor rotation speeds. Result of the masters thesis are aforementioned optimal rotation speeds for different performance profiles of the fridge-freezer and instructions on when the appliance should work in which profile.

Zaključna naloga obravnava delovanje merilnega sistema za detekcijo smeri vira hrupa v zunanjem urbanem okolju, opisuje dognanja ob uporabi merilnega sistema, izvlečke in zaključke teh meritev. Obsega meritev usmerjenosti merilnega sistema v različnih frekvenčnih območjih pod nadzorovanimi pogoji v okolju gluhe sobe. Namen naloge je bil ugotoviti, kako merilni sistem deluje v prostem zvočnem polju v okolju, s točkovnimi zvočnimi viri, in s kakšno ločljivostjo zaznava točkovne vire z namenom prikaza izmerjenih informacij v lažje razumljive oblike, ki se jih nato lahko primerja z ročnimi meritvami na standardiziranem merilniku. Naloga torej analizira možnost avtomatizacije meritev hrupa v okolju na osnovi prostorskega filtriranje zvočnih virov. Merilni sistem je bil postavljen na skrbno izbrana merilna mesta, kjer so potekale meritve različnih virov hrupa z namenom določanja njihove smeri in vpliva na rezultate merjenja dominantnega merjenega izvora hrupa, ter njihov učinek na obnašanje sistema. Po opravljenih meritvah je bilo ugotovljeno, da sistem nudi učinkovito in natančno določanje in ločevanje izvorov hrupa ozadja od hrupa merjenega vira. Z meritvami smo potrdili zasnovo merilnega sistema, ki omogoča hitro in preprosto obdelavo podatkov in njihovo vizualno predstavitev na razumljiv način. This bachelor’s thesis contains the analysis and results of the system for automatic measurement of noise source direction in the external urban surroundings, describing the findings using the measurement system, the extracts, and the conclusions of these measurements. It involves measuring the direction of the system in different frequency ranges under the controlled conditions in an anechoic chamber. The purpose of the thesis was to observe how the system operates in a free sound field with multiple directed noise sources and the resolution with which it detects those sources, with the intent to convey the gathered information into a more understandable form that can then be compared with manual measurements on a standardized meter. The task, therefore, analyzes the possibility of automating the measurement of noise in the environment based on spatial filtering of sound sources. Therefore, the system was set together with a control computing unit in a carefully selected area where measurements of different noise sources were carried out in order to determine their direction and the impact they have on the main observed source as well as the influence of multiple sources on the behavior of the system. After the measurements, it was determined that the system offers effective and precise determination and separation of the effects of the measured sources. It can also process and present the gathered information in an easily comprehensible way.

Zaključna naloga se poglablja v problematiko zaznavanja pogonskih sredstev pri jadralnih letalih. Namen naloge je akustična analiza hrupa v kabini jadralnega letala v pogojih z motorjem ter brez njega in razvoj programa, ki je sposoben ločiti med tema dvema načinoma leta. Praktični del zajema snemanje hrupa znotraj kabine v jadralnem letalu v pogojih letenja z in brez motorja pri različnih pogojih. Ti pogoji zajemajo let pri različnih hitrostih, koordinirani in nekoordinirani let, let z odprtim in zaprtim oknom, uvlečenim in izvlečenim podvozjem ter pri različnih obratih motorja. V obsegu praktičnega dela zaključne naloge je tudi hrup motorja na tleh, brez aerodinamičnega hrupa zaradi letenja. Razvojni del sloni na akustični analizi, izračunu psihoakustičnih značilk ter klasifikaciji zvoka glede na značilke dveh načinov leta. This thesis is devoted to examining the problems of engine detection in sailplanes. The purpose of this thesis is to develop a program capable of differentiating flights and parts of flights with the use of an engine from ones without an engine based on an acoustic analysis of noise inside a sailplane cabin during flight. The practical part of this thesis covers recording of noise inside the cabin of a sailplane during flight with and without the use of an engine in different conditions. These conditions include flying at different speeds, coordinated and uncoordinated flight, flying with an open and closed window and with and without landing gear deployed, as well as flying with the engine at different RPM settings. The practical part of this thesis also includes recording of engine noise on the ground, when no flight-induced aerodynamic noise is present. The development part of this research is based on acoustic analysis, calculation of acoustic and psychoacoustic features and classification of noise based on features of two different flight regimes.

Zaradi močne konkurence na trgu je kontrola hrupa elektromotorjev vedno bolj prisotna in vedno bolj stroga, zato podjetje teži k nenehnemu znižanju hrupa elektromotorjev. Prav tako je z ustrezno obdelavo zvoka, lahko le-ta močan indikator napak na elektromotorjih. Podjetje že izvaja različne kontrolne meritve, ki določajo ustreznost motorja, a se pri montaži pojavijo napake, ki jih je težko zaznati preko merjenja teh fizikalnih veličin. Z obstoječimi kontrolnimi napravami za hrup, pa se opazuje le absolutne vrednosti hrupa in vibracij (klasičen pristop), kateri se večkrat izkaže za neučinkovitega. V delu je predstavljen povzetek raziskave, ki je bila opravljena na 20-ih vzorcih elektromotorjev. Cilj naloge pa je preveriti ali lahko s pomočjo računanja psiho-akustičnih cenilk ločimo ustrezne vzorce od neustreznih. Because of the strong competition in electric motors manufacturing, manufacturers put more and more effort in noise control. Besides, noise might be a very strong indicator of possible motor errors, if observed properly. Company is already measuring many properties of electric motor although during the mounting process of electric motors, many mistakes can be done and some of them can not be detected with those measurements. Existing control devices are based on absolute values of noise and vibration (classic approach), which in many cases, doesn't seem to be effective, so use of a psycho-acoustic approach in failure detection, might be worth trying. In this work, the research was done using 20 sample electric motors. The goal of the research was to determine, whether we can distinguish between good and bad samples, by extracting and evaluating sound features.

V okviru magistrskega dela je bila opravljena validacija numerične simulacije dinamičnega pojava tokovno povzročenega zvoka. Podana je bila ustrezna teoretična podlaga, sledi integralna obravnava elementa z značilnim pojavom žvižga v obliki eksperimenta, ki se je izvedel v Laboratoriju za energetske delovne stroje in tehnično akustiko na Fakulteti za strojništvo v Ljubljani. Osrednji del magistrskega dela zajema nastavitve in zagon numerične simulacije v programskem okolju Fluent. Sledi analiza vplivnih spremenljivk s pomočjo hitre Fourierjeve transformacije in slikovna obdelava animacije tokovnega polja z lastno programsko kodo. Slednje je izkazalo soodvisnost značilnih amplitud v frekvenčni domeni tokovnega polja in akustičnega pojava. Within presented thesis validation of numerical simulation regarding dynamic phenomenon of flow generated sound was performed. An appropriate theoretical basis was given, followed by the integral processing of an element with a typical phenomenon of whistle in the form of an experiment carried out in the Laboratory for pumps, compressors and technical acoustics at the Faculty of mechanical engineering in Ljubljana. The main part of the master's thesis covers the settings and start of numerical simulation in the Fluent programming environment. The analysis of influential variables is followed by the fast Fourier transformation of the sound field and the image processing of the animation of the flow field with our own program code is done. The latter showed the interdependence of the characteristic amplitudes in the frequency domain of the flow field and the acoustic phenomenon.

Uvod: Hiter razvoj področja ortotike in protetike in uporaba novih materialov in postopkov izdelave lahko privede tudi do novih tveganj za zdravje delavcev v ortotičnih in protetičnih delavnicah. Namen: S pomočjo meritev fizikalnih in kemičnih parametrov delovnega okolja smo želeli ugotoviti, kakšne so vrednosti parametrov ter kateri ukrepi so potrebni za morebitno izboljšanje delovnega okolja. Metode dela: V dveh izbranih delavnicah za ortotiko in protetiko smo izvedli meritve mikroklime, hrupa, osvetljenosti, koncentracije prašnih delcev in koncentracije CO2. Določili smo posamezna merilna mesta in izvedli meritve s petimi različnimi merilnimi inštrumenti. Dobljene vrednosti smo primerjali z mejno vrednostjo in ugotavljali, ali ustrezajo zahtevam. Rezultati: Rezultati so pokazali, da v obeh delavnicah vrednosti meritev mikroklimatskih pogojev ustrezajo predpisanim zahtevam, neustrezna je samo temperatura v zasebnem centru OP v etaži 1, ki znaša 17 ºC. Ravni hrupa presegajo mejno raven izpostavljenosti 87 dB v obeh delavnicah na merilnih mestih pri uporabi vbodne žage in kompresorja. Koncentracija prašnih delcev je pri večini merilnih mest nižja od mejne vrednosti 6 mg/m³, večje koncentracije pa so bile na mestu, kjer se brusi poliuretan in reže mavec. Koncentracija CO2 v laboratoriju na ZF znaša 680 ppm, v izbranem centru OP pa med 502 ppm in 1708 ppm, kar je manj od mejne vrednosti 5000 ppm. Glede na dobljene rezultate PMV in PPD so bolj toplotno ugodni pogoji v zasebnem centru ortotike in protetike. V laboratoriju na ZF indeks PMV presega zahtevano mejo na polovici merilnih mest. V izbranem centru ortotike in protetike je indeks PMV zunaj meje v prostoru D in v ambulantni sobi. Razprava in sklep: Ugotovili smo, da ob uporabi obdelovalnih strojev, vbodnih žag in kompresorjev lahko ravni hrupa dosežejo vrednosti, ki so nevarne za poškodbo sluha. Da bi dobili dejansko stanje dnevne izpostavljenosti hrupu, bi bilo potrebno ponoviti meritve z osebnimi dozimetri. Delovni pogoji so sicer primerni in so si podobni v obeh delavnicah. Na podlagi dobljenih rezultatov svetujemo uporabo osebne varovalne opreme za zaščito sluha in dihal. Introduction: The rapid development of the field of orthotics and prosthetics and the use of new materials and manufacturing processes can lead to adverse short and long term consequences on the health. of workers in orthotics and prosthetics workshops. Purpose: The aim of the study was to measure the physical and chemical parameters of work environment and determine their values in order to propose necessary measures intended for the potential improvement of work environment. Methods: In two selected orthotics and prosthetics workshops measurements of microclimate, noise, illumination, dust concentration and carbon dioxide concentration were carried out. The measuring points were determined in advance and measurements with five different measuring instruments were recorded. The obtained values were then compared to the set limit values and the compliance with the formal requirements was checked. Results: The results show that in both workshops most of the obtained microclimate values are in accordance with the formal requirements. The temperature in the private O&P centre, however, was 17 ºC, which is unsuitable. Also, exposure to noise exceeded the limit of 87 dB in both workshops during the use of a saw blade and a compressor. The concentration of dust particles was lower than the limit value of 6 mg/m3 at most measuring points. Higher concentration was recorded at the measuring point where polyurethane and plaster were sanded and cut. The CO2 concentration at Faculty of Health Sciences laboratory was 680 ppm and the CO2 concentration between 502 ppm and 1708 ppm was detected at the private O&P center, which is still considerably lower than the 5000 ppm limit. Based on the PMV and PPD results, more favourable thermal conditions prevailed in the private center of O&P. At the Faculty of Health Sciences laboratory, the PMV required limit was exceeded at the half of the measuring points. In the private O&P centre, the PMV was above the limit in the section D and ambulatory care area. Discussion and conclusion: The data collected from the current study suggest that during the use of machine tools, exposure to high levels of occupational noise can reduce hearing acuity and may be detrimental to the health of orthotists and prosthetists. To acquire the actual daily noise exposure repeated measurements with personal dosimeters would be required. Working conditions were similar and seemed appropriate in both workshops. Based on the findings of this study, we recommend the use of the personal protective equipment for hearing and respiratory protection.

V splošnem je lahko nek strojni del vgrajen v avtomobile različnih avtomobilskih proizvajalcev, pri tem pa so uporabljeni različni povezovalni elementi in nosilna struktura. To pomeni, da bodo kljub enakemu izvoru vibracij (motor, menjalnik, ...), dinamske lastnosti celotnega sistema pri istih obratovalnih pogojih popolnoma različne. Za zagotovitev ustreznega zvočnega oz. akustičnega udobja, katerega zahteve s prihodom električnih vozil in avtonomne vožnje postajajo vse višje, je potrebno znati dobro popisati dinamske lastnosti vibracijskih izvorov. V tem magistrskem delu sta predstavljeni in preizkušeni metoda blokiranih sil in metoda točkovne pomičnosti vibracijskega izvora, obe namenjeni karakterizaciji vibracijskih izvorov s pomočjo meritev na lokaciji realnega sistema. Največja prednost omenjenih metod pred obstoječimi je, da lahko neodvisne lastnosti izvora vibracij pridobimo kar iz meritev na lokaciji, opravljenih na celotnem sistemu (izvor + prejemnik vibracij) in razstavljanje sistema ni potrebno. Metoda točkovne pomičnosti omogoča izračun neodvisnih pasivnih dinamskih lasnosti v obliki frekvenčne prenosne funkcije (pomičnost) tako za izvor, kot tudi za prejemnik vibracij v njunih kontaktnih točkah. Nasprotno pa metoda blokiranih sil ponuja možnost izračuna neodvisnih aktivnih dinamskih lastnosti izvora vibracij, t.i. blokiranih sil, torej lastnosti, ki jih izvor ima v času obratovanja. Lastnost blokiranih sil je, da pri določenih obratovalnih pogojih ostajajo enake, tudi če na izvor vibracij pritrdimo drugo sprejemno strukturo. Pri tem je potrebno poudariti. da se beseda "neodvisen" nanaša na lastnost in pomeni, da je le-ta enaka, kot če bi bila izmerjena neposredno na izvorni oz. prejemni strukturi in ne v sestavu. Metodi sta preizkušeni numerično ter z eksperimentom v laboratoriju, na sistemu dveh nosilcev, povezanih z gumenim kot tudi z jeklenim oz. aluminijastim vmesnikom. Numerični preizkus je izveden v programu za analizo z metodo končnih elementov. V začetni fazi so simulacije izvedene z 1D končnimi elementi (nosilec, vzmet) z namenom, da se izniči efekt velikosti kontaktnih površin in mase povezovalnega elementa. V nadaljevanju so simulacije izvedene s 3D končnimi elementi, kjer se preveri tudi vpliv velikosti kontaktne površine, togosti povezovalnega elementa, števila kontaktnih točk in delovanje metode končnih razlik, ki je uporabljena za izračun frekvenčnih prenosnih funkcij. Obsežen del naloge je namenjen tudi raziskavi vpliva rotacijskih prostostnih stopenj na izračun blokiranih sil oziroma točkovne pomičnosti vibracijskega izvora. Izkaže se, da je vpliv rotacijskih prostostnih stopenj na izračun blokiranih sil izredno pomemben, še posebej v primerih, kjer izvor in prejemnik vibracij povezuje toga struktura. Metoda je namreč razvita za točke in točkovne povezave, kar pa v realnem svetu ni mogoče, saj vedno upravljamo s površino, pa čeprav je le-ta še tako majhna. V primeru površin, obratovalne sile na neki oddaljenosti od sredinske - privzete kontaktne točke tvorijo obratovalne momente, ki pa ne smejo biti zanemarjeni, v kolikor želimo natančen izračun in veljavne rezultate. Kot že zapisano, metodi temeljita na izračunu blokiranih sil oziroma točkovne pomičnosti v točki na izvoru vibracij, kjer je le-ta povezan z prejemno strukturo. Ta točka je v večini primerov nedostopna saj leži na kontaktni površini in zatorej vzbujanje strukture oz. merjenje odziva tam ni mogoče. S tem razlogom je v tem magistrskem delu uporabljena metoda končnih razlik, ki obenem omogoča tudi relativno enostavno vzbujanje strukture in merjenje odziva v rotacijskih prostostnih stopnjah. V nalogi je teoretično in eksperimentalno prikazano, da neodvisne pasivne ali aktivne lastnosti vibracijskega izvora lahko pridobimo iz meritev na lokaciji. Pri tem se metoda blokiranih sil izkaže za zelo obetavno, saj za sistem nosilcev omogoča natančen izračun blokiranih sil in njihovo nadaljno uporabo za predvidevanje odziva sistema s spremenjenim prejemnikom vibracij. V primeru prožnih povezovalnih struktur zadostuje uporaba in merjenje le v smeri translatornih prostostnih stopnj, v kolikor pa je vmesnik tog, je za natančen rezultat potrebno vključiti tudi rotacijske prostostne stopnje. Metoda točkovne pomičnosti se izkaže za manj verodostojno, saj so v procesu razvoja uporabljene določene predpostavke in poenostavitve, ki pa se izkažejo za nepravilne v primerih, ko izvor vibracij in prejemnik povezuje tog vmesnik, katerega masa v primerjavi z maso celotnega sestava ni zanemarljiva. Metoda je smislena za uporabo in daje relativno dobre rezultate v primerih, ko izvor in prejemnik vibracij povezuje manjše število povezovalnih elementov, pri tem pa je povezovalna struktura prožna, na primer gumen vmesnik. In general, one machine part can be used by different automotive manufacturers, where mounted by diverse resilient mounts and attached to different supporting structures. That means, the dynamic properties of each system containing a vibration source (engine, gearbox,...) and receiver (chassis) will differ considerably from each another. In this Master's thesis a relatively new In-situ blocked force method and In-situ source mobility method, for characterization of vibration sources from in-situ measurement, are described and tested. The main advantage of these methods is ability to get an independent source property from measurement executed on source-receiver assembly in installed condition. The methods are checked numerically as well as in the lab, with experiment on a real system that consists by two straight beams, connected once by rubber and also by steel or aluminium element. It is shown that active and passive independent source properties can be obtained from in-situ measurement. Especially the blocked force method was found very promising as it enables, for the source-receiver beam system, to calculate accurate blocked forces and use them for further response prediction of a system with changed receiver structure.

Hidravlika se uporablja na mnogih področjih, standardi se višajo. Današnje stanje tehnike govori v smeri, kaj obstaja in česa se poslužimo, da zmanjšamo hrup. Za zmanjšanje hrupa uporabimo najnovejše črpalke, gibke cevi, hidravlične ventile z nizko ravnjo hrupa, linijske dušilce itn. V drugem delu so postopki meritev in prikazani rezultati sanacije. Preprosto in za zmerno ceno lahko zmanjšamo hrup zvočnega vira. Absorpcijska pena je boljša od izolacijske gume, kaj uporabimo, pa je stvar kompromisa. Hydraulic is used in many areas and standards are rising. Today's state of the art of what exists and what is employed to reduce the noise. For noise reduction using the latest pump , hoses , hydraulic valves with low noise production , linear dampers , etc.. In the second part are measurement procedures and presents the results of rehabilitation. We can reduce noise of the sound source imply and for the affordably price. Absorbing foam is better than rubber insulation but what we use is a matter of compromise.

V diplomski nalogi sem na podlagi javnomnenjske raziskave ugotavljal pomembnost dejavnikov, ki vplivajo na vrednost stanovanjskih nepremičnin. Poudarek sem dal na zaznavanju motečega hrupa in preveril koliko, če sploh, potencialni kupci stanovanjskih nepremičnin za lastno uporabo upoštevajo analizirane izbrane dejavnike. Predstavljeni so osnovni pojmi ter slovenski pravni predpisi s področja evidentiranja nepremičnin. Podrobno so predstavljene evidence in viri podatkov, ki so potrebni za objektivno ocenjevanje vrednosti nepremičnin. Narejena je primerjava podatkov iz evidenc in podatkov iz nepremičninskih oglasov, ki zanimajo potencialne kupce. Ugotavljam, da lahko s pomočjo javnih evidenc cenilec pridobi raznovrstne podatke, ki so pomembni pri vrednotenju nepremičnin, vendar pa manjkajo nekateri podatki, ki tudi zanimajo potencialne kupce. To so stopnja hrupa, varnost soseske, razgled, kakovost zraka, stopnja tveganja pred naravnimi nesrečami, atraktivnost arhitekture ter kvaliteta gradnje. Rezultati javnomnenjske raziskave kažejo, da je potencialnim kupcem najbolj pomembna urejenost lastninskih pravic na nepremičninah, nato kakovost zraka, kvaliteta gradnje in varnost pred naravnimi nesrečami. Anketiranci menijo, da so hrup, varnost soseske in razgled v splošnem manj pomembni dejavniki, vendar je lahko vsak omenjeni dejavnik v določenih razmerah zelo pomemben, če preseže mejne vrednosti sprejemljivega. Izpostavili so prometni hrup, ki je še posebej moteč za prebivalce, ki živijo v bližini prometno obremenjenih cest, ter notranji hrup v večstanovanjskih stavbah. This thesis is based on a research of perceptions of factors that are impacting the value of residential real estate, based on a public survey. I have put an emphasis on the perception of disruptive noise and check how many, if any, of the potential buyers of residential properties take analyzed factors into account. Basic concepts of Slovenian legal real estate regulation of real estate data accusation are introduced. Databases and data source required to objectively assess the value of real estate are presented. A comparison of data from the records and data from the real estate ads that interest potential buyers has been made. I found out that appraisers with the help of public valuation records can acquire various data that are important in the evaluation of real estate, but there is some data missing that also interest potential buyers. Such data are noise level, neighborhood safety, air pollution, the risk of natural disasters, attractiveness of architecture design and construction quality. The result of the survey shows, that potential buyers mostly care about legal owners property rights, air pollution, construction quality and finally the risk of natural disasters. Survey participants believe that disruptive noise, neighborhood safety and views are generally less important factors, but each of those can be very important when exceeding acceptable limits. They have stressed that the most disturbing is the traffic noise nearby busy roads and interior noise in apartment buildings.