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3. Methods of Rut Depth Measurements on Forwarder Trails in Lowland Forest.

Author

Lovrinčević, Mihael, Papa, Ivica, Popović, Maja, Janeš, David, Poršinsky, Tomislav, Pentek, Tibor, and Đuka, Andreja

Subjects
BATHYMETRY, OPTICAL radar, LIDAR, GLOBAL Positioning System, FOREST soils
Abstract

Rutting measurements are a significant part of scientific research on the impact of forest vehicles on the forest soils and damage to the forest transport infrastructure. Although photogrammetric methods of measurement or measurements based on LiDAR (light detection and ranging) data are increasingly being used for rutting measurements, the previous research conducted using these methods indicated the challenge of recording water-filled ruts. For this reason, it is necessary to define a reliable method of rutting field measurement in lowland forest stands characterized by a high level of groundwater that fills the ruts shortly after the passage of forest vehicles. This research analyzed the measurement accuracy using a total station and a GNSS RTK device with a CROPOS correction base in relation to the measuring rod that represented the reference method. Based on recorded and processed data, ruts are displayed in two ways: as net and as gross value of rut depth. The analysis of net rutting revealed a statistically significant difference between the calculated rut depths based on measurements with a GNSS RTK device and other methods. On average, the net rutting measured by the GNSS RTK device was 2.86 cm smaller than that of the reference method. When calculating the gross rutting, which consisted of the net rut depth and the bulge height, no statistically significant difference was found between the measurement methods used. Based on this result, the bulge height was also analyzed, and showed a statistically significant difference between the data recorded by the GNSS RTK device and other methods. It can be concluded that measuring the depth of ruts with a total station gives accurate data and represents the optimal modern field measurement method for the same or similar terrain conditions. In contrast, the GNSS RTK device, which constantly gives higher elevation points, can be used to measure gross rutting. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Room Temperature Device Performance of Electrodeposited InSb Nanowire Field Effect Transistors

Author

Das, Suprem R., Delker, Collin J., Zakharov, Dmitri, Chen, Yong P., Sands, Timothy D., and Janes, David B.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

In this study, InSb nanowires have been formed by electrodeposition and integrated into NW-FETs. NWs were formed in porous anodic alumina (PAA) templates, with the PAA pore diameter of approximately 100 nm defining the NW diameter. Following annealing at 125C and 420C respectively, the nanowires exhibited the zinc blende crystalline structure of InSb, as confirmed from x-ray diffraction and high resolution transmission electron microscopy. The annealed nanowires were used to fabricate nanowire field effect transistors (NW-FET) each containing a single NW with 500 nm channel length and gating through a 20nm SiO2 layer on a doped Si wafer. Following annealing of the NW-FETs at 300C for 10 minutes in argon ambient, transistor characteristics were observed with an ION ~ 40 uA (at VDS = 1V in a back-gate configuration), ION/IOFF ~ 16 - 20 in the linear regime of transistor operation and gd ~ 71uS. The field effect electron mobility extracted from the transconductance was ~1200 cm2 V-1 s-1 at room temperature. We report high on-current per nanowire compared with other reported NW-FETs with back-gate geometry and current saturation at low source-drain voltages. The device characteristics are not well described by long-channel MOSFET models, but can qualitatively be understood in terms of velocity saturation effects accounting for enhanced scattering, Comment: 14 pages, 4 figures

Published
2011
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5. Improved current saturation and shifted switching threshold voltage in In2O3 nanowire based, fully transparent NMOS inverters via femtosecond laser annealing

Author

Lee, Chunghun, Park, Sangphill, Srisungsitthisunti, Pornsak, Kim, Seongmin, Zhou, Chongwu, Janes, David B., Xu, Xianfan, Roy, Kaushik, Ju, Sanghyun, and Qi, Minghao

Subjects
Physics - Optics
Abstract

Transistors based on various types of non-silicon nanowires have shown great potential for a variety of applications, especially for those require transparency and low-temperature substrates. However, critical requirements for circuit functionality such as saturated source-drain current, and matched threshold voltages of individual nanowire transistors in a way that is compatible with low temperature substrates, have not been achieved. Here we show that femtosecond laser pulses can anneal individual transistors based on In2O3 nanowires, improve the saturation of the source-drain current, and permanently shift the threshold voltage to the positive direction. We applied this technique and successfully shifted the switching threshold voltages of NMOS based inverters and improved their noise margin, in both depletion and enhancement modes. Our demonstration provides a method to trim the parameters of individual nanowire transistors, and suggests potential for large-scale integration of nanowire-based circuit blocks and systems., Comment: 18 pages, 4 figures

Published
2010

6. Pairs of Gold Electrodes with Nanometer Separation Performed over SiO$_2$ Substrates with a Molecular Adhesion Monolayer

Author

Mahapatro, Ajit K., Ghosh, Subhasis, and Janes, David B.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Pairs of electrodes with nanometer separation (nano-gap) are achieved through an electromigration-induced break-junction (EIBJ) technique at room temperature. Lithographically defined gold (Au) wires are formed by e-beam evaporation over oxide coated silicon substrates silanized with (3-Mercaptopropyl)trimethoxysilane (MPTMS) and then subjected to electromigration at room temperature to create a nanometer scale gap between the two newly formed Au electrodes. The Si-O-Si covalent bond at the SiO$_2$ surface and the Au-sulphur (Au-S) bond at the top evaporated Au side, makes MPTMS as an efficient adhesive monolayer between SiO$_2$ and Au. Although the Au wires are initially 2$\mu$m wide, gaps with length $\sim$1nm and width $\sim$5nm are observed after breaking and imaging through a field effect scanning electron microscope (FESEM). This technique eliminates the presence of any residual metal interlink in the adhesion layer (chromium or titanium for Au deposition over SiO$_2$) after breaking the gold wire and it is much easier to implement than the commonly used low temperature EIBJ technique which needs to be executed at 4.2 K. Metal-molecule-metal structures with symmetrical metal-molecule contacts at both ends of the molecule, are fabricated by forming a self-assembled monolayer of -dithiol molecules between the EIBJ created Au electrodes with nanometer separation. Electrical conduction through single molecules of 1,4-Benzenedimethanethiol (XYL) is tested using the Au/XYL/Au structure with chemisorbed gold-sulfur (Au-S) coupling at both contacts., Comment: 12 pages, 4 figures

Published
2005

10. A Device Structure for Electronic Transport Through Individual Molecules with Strong Coupling to Metallic Electrodes

Author

Ghosh, Subhasis, Halimun, Henny, Choi, Jaewon, Lodha, Saurabh, and Janes, David

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present a simple and reliable method for making electrical contacts to small organic molecules with thiol endgroups. Nanometer-scale gaps between metallic electrodes have been fabricated by passing a large current through a lithographically-patterned Au-line with appropriate thickness. Under appropriate conditions, the passage of current breaks the Au-line, creating two opposite facing electrodes separated by a gap comparable to the length of small organic molecules. Current-voltage characteristics have been measured both before and after deposition of short organic molecules. The resistance of single 1,4-benzenedithiol and 1,4-bezenedimethanedithiol molecules were found to be 9M$\Omega$ and 26M$\Omega$, respectively. The experimental results indicate strong electronic copuling to the contacts and are discussed using a relatively simple model of mesoscopic transport. The use of electrodes formed on an insulating surface by lithography and electromigration provides a stable structure suitable for integrated circuit applications.

Published
2004
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11. Semantic Metastandards Will Unlock IoT Interoperability

Author

Janes, David P, Akan, Ozgur, Series editor, Bellavista, Paolo, Series editor, Cao, Jiannong, Series editor, Coulson, Geoffrey, Series editor, Dressler, Falko, Series editor, Ferrari, Domenico, Series editor, Gerla, Mario, Series editor, Kobayashi, Hisashi, Series editor, Palazzo, Sergio, Series editor, Sahni, Sartaj, Series editor, Shen, Xuemin Sherman, Series editor, Stan, Mircea, Series editor, Xiaohua, Jia, Series editor, Zomaya, Albert Y., Series editor, Mandler, Benny, editor, Marquez-Barja, Johann, editor, Mitre Campista, Miguel Elias, editor, Cagáňová, Dagmar, editor, Chaouchi, Hakima, editor, Zeadally, Sherali, editor, Badra, Mohamad, editor, Giordano, Stefano, editor, Fazio, Maria, editor, Somov, Andrey, editor, and Vieriu, Radu-Laurentiu, editor

Published
2016
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14. Korisni GIS alati pri utvrđivanju dostupnosti šumske površine

Author

Janeš, David, Papa, Ivica, Matijašević, Sandi, Žarković, Ivan, Lovrinčević, Mihael, Đuka, Andreja, Janeš, David, Papa, Ivica, Matijašević, Sandi, Žarković, Ivan, Lovrinčević, Mihael, and Đuka, Andreja

Abstract

Sažetak Svrha ovog članka detaljno je pojašnjenje problematike funkcionalnog pristupa utvrđivanja dostupnosti šumske površine, odnosno jednoznačnog i ujednačenog utvrđivanja gustoće cesta i relativne otvorenosti promatrane šumske površine koja se najčešće prikazuje na razini gospodarske jedinice. Navedena dva parametra predstavljaju neizostavne čimbenike u kasnijoj fazi planiranja optimalne mreže šumskih prometnica. Kao vodič postupka otvaranja šuma poslužio je važeći Pravilnik o provedbi mjere M04 »Ulaganja u fizičku imovinu«, podmjere 4.3. »Potpora za ulaganja u infrastrukturu vezano uz razvoj, modernizaciju i prilagodbu poljoprivrede i šumarstva«, tipa operacije 4.3.3. »Ulaganje u šumsku infrastrukturu« iz Programa ruralnog razvoja Republike Hrvatske za razdoblje 2014. – 2020. (NN 106/2015, 65/2017, 77/2017 i 84/2018), koji propisuje način izrade Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture. U ovome radu prikazani su korisni alati unutar dva najzastupljenija GIS programska paketa: komercijalnog ArcGIS programa te besplatnog QGIS programa (eng. open source). Detaljno su prikazani i pojašnjeni GIS alati unutar oba programa, a koji mogu pomoći pri izradi Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture. Ovaj stručni rad sadrži korisne informacije za sve koji se bave problematikom utvrđivanja dostupnosti šumske površine, odnosno optimalnog planiranja šumskih cesta, te za utvrđivanje stvarnog stanja gustoće cesta i relativne otvorenosti šuma kojom gospodare., SummaryThe purpose of this paper is a detailed explanation of determining the accessibility of the forest area by calculating road density and the relative forest openness on the examples of two management units. The mentioned two parameters represent indispensable factors in the later phase of planning the optimal forest traffic infrastructure network. As a guide for increasing forest accessibility, a valid Bylaw on measure implementation M04 »Investments in physical assets«, by-measure 4.3 »Grant for investments in development, modernization and customization of agriculture and forestry«, operation type 4.3.3 »Investments in forest infrastructure« from the Program of Rural Development in the Republic of Croatia in the period from 2014 to 2020 (NN 106/15) (NN 106/2015, 65/2017, 77/2017 and 84/2018), which in its appendix No. 1 – Form for the Effectiveness Study of Primary Forest Road Traffic Infrastructure prescribes the preparation of the Effectiveness study of the forest road network. This paper presents valuable tools within the two most common GIS software packages: the commercial ArcGIS program and QGIS, an open-source program. The GIS tools within both programs, which are necessary for preparing the Effectiveness study of the forest road network, are presented and explained in detail. This professional paper contains valuable information for all who deal with the problem of determining the availability of forest area, i.e. the optimal planning of forest road layout, as well as for determining the actual state of road density and the relative openness of the forests.

Published
2023

17. Wishlist web application development

Author

Janeš, David and Slavuj, Vanja

Abstract

U ovome diplomskom radu prikazan je cjelokupni postupak izrade web aplikacije za stvaranje lista želja koristeći okruženja Django i Bootstrap. U prvom dijelu rada opisani su besplatni web okviri Django, Bootstrap i JavaScript programski jezik, njihova povijest, razvoj i princip rada. U glavnom dijelu rada detaljno je opisan postupak izrade aplikacije te svih njenih funkcionalnosti uz popratne slike ekrana i kodova. Na kraju rada dan je zaključak te osobni osvrt na korištenje dvaju web okvira.

Published
2022

20. Pokazatelji primarne otvorenosti četiri reljefna područja šuma

Author

Janeš, David, Đuka, Andreja, Papa, Ivica, Pentek, Tibor, Moro, Maja, Žarković, Ivan, Poršinsky, Tomislav, Janeš, David, Đuka, Andreja, Papa, Ivica, Pentek, Tibor, Moro, Maja, Žarković, Ivan, and Poršinsky, Tomislav

Abstract

Poznavanje značajki gustoće i prostornog rasporeda šumskih cesta različitih reljefnih područja olakšava daljnje procese planiranja i projektiranja budućih šumskih cesta. Istraživanjem su proučavani osnovi pokazatelji otvo­renosti šuma primarnim šumskim prometnicama na uzorku od dvadeset gospodarskih jedinica raspodjeljenih u četiri reljefna područja, odnosno šumskih bioklimata: 1) Nizinskih šuma hrasta lužnjaka, 2) Brežuljkastih šuma hrasta kitnjaka, 3) Brdskih bukovih šuma te 4) Gorskih bukovo – jelovih šuma.Postojeće i unaprijeđeno (na temelju idejnih trasa nultih linija) stanje primarne otvorenosti šuma dvadeset primjer­nih gospodarskih jedinica, provedeno je kroz analizu sljedećih pokazatelja: gustoću mreže šumskih cesta, geo­metrijsku srednju udaljenost privlačenja drva, faktor mreže šumskih prometnica te primarnu relativnu otvo­re­nost. Za valorizaciju nehomogenosti površina istraživanih gospodarskih jedinica korišten je faktor razvedenosti šumske površine, a za razinu zahtjevnosti terena udjel površine s nagibom > 33 %.Polučeni rezultati primarne otvorenosti šuma, ukazuju na sličnosti i razlike mreže šumskih cesta pojedinih reljefnih područja šuma, odnosno najveće vrijednosti gustoće cesta pojedinog šumskog bioklimata za izvrsnu relativnu otvo­renost šuma. Ostvareni rezultati potvrđuju propisane vrijednosti ciljane gustoće cesta po reljefnim područjima (Pravilnik o provedbi mjere 4 »Ulaganja u fizičku imovinu«, podmjere 4.3. »Potpora za ulaganja u infrastrukturu vezano uz razvoj, modernizaciju i prilagodbu poljoprivrede i šumarstva«, tipa operacije 4.3.3. »Ulaganje u šumsku infrastrukturu« iz programa ruralnog razvoja Republike Hrvatske za razdoblje 2014. – 2020.), budući da primar­na otvorenost veća od ciljanih vrijednosti ne daje značajne pozitivne učinke., Knowledge of the characteristics of the density and spatial distribution of forest roads in different bioclimates (terrain categories) facilitates further planning and design processes of future forest road networks. The basic parameters of forest accessibility based on primary forest roads were researched within twenty management units. The research was conducted in four bioclimates: 1. Common oak and floodplain forests, 2. Sessile oak forests of hilly terrain, 3. Submountainous beech forests and 4. Mountainous fir, beech-fir and spruce forests. The following parameters of forest accessibility were analysed: 1) forest road density and factor of forest area indentation, 2) average geometric timber extraction distance and road network factor and 3) primary relative forest accessibility. The obtained results indicate similarities and differences in the quality and quantity of the primary forest road network in each bioclimate.

Published
2022

22. Spatial and temporal dynamics of sanitary felling in the selective forest caused by bark beetle outbreaks

Author

Janeš, David, Đuka, Andreja, Papa, Ivica, Tomljanović, Kristijan, Franjević, Milivoj, Bončina, Andrej, Fidalgo Fonseca, Teresa, and Ballian, Dalibor

Subjects
bark beetles outbreaks, fir, forest accessibility, spruce, terrain
Abstract

This paper presents the dynamics of sanitary fellings in selective forests of Croatia caused by bark beetle outbreaks from 2016 to 2020 in four management units of 7, 275.890 ha in area. The area of sanitary felling i.e. clear-cuts amounted to 58.125 ha as follows: 1) Gornja Dobra, λ 381, 617.420 N and φ 503, 5383.876 E, area 5.236 ha, 2) Carevići 1, λ 383, 828.331 N and φ 503, 1964.131 E, area 16.520 ha, 3) Carevići 2, λ 382, 853.335 N and φ 503, 2332.054 E, area 3.316 ha, 4) Radoševići, λ 385, 005.686 N and φ 503, 0234.891 E, area 6.137 ha, 5) Lučice, λ 367, 335, 940 N and φ 502, 8106.871 E, area 15.886 ha, 6) Sunger 1, λ 365, 690.816 N and φ 502, 616.653 E, area 8.444 ha and 7) Sunger 2, λ 365, 961.778 N and φ 502, 3365.046 E, area 3.587 ha. Mean size of the felling area was 8.304 ha. The research was conducted with a: 1) commercial GPS device Garmin GPSMAP 66s, 2) Total station STONEX TS R35 WINCE, 3) RTK GNSS receiver STONEX S900A and 4) UAV DJI Inspire 1 V2.0, camera DJI X3. The research analyses the influence of the amount of felled timber in the affected management units with the following parameters:  terrain exposure expressed by a wind rose (8 sides) where the dominant side of the world of the observed focus is expressed ;  altitude, which is defined by the interval of 100 m height above sea level ;  terrain slope with five classes: 1) 0-10%, 2) 11-20%, 3) 21-33%, 4) 34-50% and 5) > 50% ;  parameters of the forest accessibility: 1) road density (m/ha), 2) average geometric timber extraction distance, and 3) relative forest openness. The average terrain slope of the investigated seven areas of bark beetle outbreaks ranged from 1.7% to 40.17%. The average height above sea level ranged from 473 m to 793 m. Relative forest openness ranged from 26.16% to 100.00%. The average geometric timber extraction distance was 161.75 m ± 103.25m.

Published
2022

26. Analiza terenskih i sastojinskih čimbenika kao osnova za planiranje radova u pridobivanju drva i otvaranju šuma

Author

Janeš, David, Papa, Ivica, Moro, Maja, Žarković, Ivan, Pentek, Tibor, Poršinsky, Tomislav, and Đuka, Andreja

Subjects
razredba terena, bioklimat, razvedenost šumskih cesta
Abstract

Istraživane su terenske i sastojinske prilike gospodarskih državnih i privatnih šuma iz dostupnih prostornih podataka koje će potom omogućiti stvaranje osnovice za razredbu terena za potrebe pridobivanja drva i otvaranja šuma. S gledišta pridobivanja drva te kao gospodarski najznačajnije šume izdvojena su i prikazana četiri bioklimata: 1) bioklimat jelovih, bukovo-jelovih i smrekovih šuma, 2) bioklimat brdskih bukovih šuma, 3) bioklimat bežuljkastih šuma hrasta kitnjaka te 4) bioklimat nizinskih šuma hrasta lužnjaka i poplavnih šuma. Na tim su područjima određene ove terenske i sastojinske značajke: 1) nagib terena i stjenovitost tla (pokrivenost površine), 2) način vlaženja tla i rizik od erozije tla vodom, 3) drvna zaliha, 4) stupanj razvedenosti šumskih cesta i 5) srednja udaljenost privlačenja drva kao pokazatelj otvorenosti šuma. Provedene analize mreže šumskih cesta pokazale su da postoji statistički značajna razlika između cesta bioklimata nizinskih šuma hrasta lužnjaka i poplavnih šuma te bioklimata brežuljkastih šuma hrasta kitnjaka u odnosu na ostale bioklimate. Analize šumskih cesta po pojedinom bioklimatu treba promatrati u sklopu ostalih terenskih čimbenika, kao što su stjenovitost terena te stvarnoga rizika od erozije tla vodom, koji će svoj utjecaj, uz nagib terena, iskazati pri planiranju budućih trasa šumskih cesta. Povezivanjem značajki terena započeto je stvaranje primjenjive razredbe terena za uvjete hrvatskoga šumarstva kao važnoga logičkoga alatu pri gospodarenju šumama i planiranju radova u šumarstvu, osobito u pridobivanju drva i otvaranju šuma.

Published
2021

27. Planiranje primarnih šumskih prometnica u gospodarskim šumama na strateškoj i taktičkoj razini

Author

Janeš, David

Subjects
Planiranje, šumske prometnice, sustavi pridobivanja drva, GIS
Abstract

Razredbe terena neophodne su za planiranje radova pridobivanja drva odnosno za daljnje planiranje otvaranja šuma. Za formiranje razredbe terena provedeno je istraživanje značajki terena (nagib terena, indeks neravnosti terena, stjenovitost tla, načini vlaženja tla te rizik od erozije tla vodom) kao i sastojinskih značajki. Upravo su sastojinske značajke odnosno bioklimati, kao prostorno definirano područje s klimatskim tipom i određenim, toj klimi prilagođenim vegetacijskim tipom – biljnom zajednicom, temelj nove razredbe terena za potrebe pridobivanja drva. Istraživanje bioklimata provedeno je na razini privatnih i državnih šuma RH, za čije potrebe je uspostavljena GIS baza podataka. Provedene analize ukazuju kako je šumsko područje Republike Hrvatske moguće, sa udjelima pridolaska podijeliti na: 1. Pretplaninske šume klekovine (0, 01%), 2. Pretplaninske bukove i smrekove šume (1, 76%), 3. Jelove, bukovo-jelove te smrekove šume (9, 49%), 4. Brdske bukove šume (18, 36%), 5. Brežuljkaste šume hrasta kitnjaka (17, 85%), 6. Nizinske šume hrasta lužnjaka i poplavne šume (17, 90%), 7. Submediteranske šume bukve i crnog bora (3, 69%), 8. Submediteranske šume medunca i crnog graba (4, 34%), 9. Submediteranske šume medunca i bijelog graba (20, 14%) i 10. Mediteranske šume i makije alepskog bora i hrasta crnike (6, 46%). Sukladno definiranim područjima pridolaska bioklimata te formiranom GIS bazom podataka istraživanog područja, jednostavnim slučajnim uzorkovanjem odabrano je 20 gospodarskih jedinica, jednoliko raspoređenih u sljedeća 4 gospodarski najznačajnija bioklimata (drvnom zalihom najbogatija) Republike Hrvatske: 1. Nizinske šume hrasta lužnjaka i poplavne šume, 2. Brežuljkaste šume hrasta kitnjaka, 3. Brdske bukove šume i 4. Jelove, bukovo-jelove te smrekove šume. Unutar 4 odabrana bioklimata prvotno je provedena analizira stupnja korekcije šumskih cesta (ŠC). U tu svrhu proučavano je bočno odstupanje svakog izraženog horizontalnog loma šumskih cesta od pravocrtnih linija kao i čimbenika korekcije šumskih cesta (odnos duljine pravocrtne linije i stvarne duljine šumske ceste između njenih točaka početka i završetka. Provedene analize potvrđuju kako se šumske ceste nizinskih šuma hrasta lužnjaka i poplavnih šuma značajno razlikuju od ŠC-a ostala 3 bioklimata po bočnom odstupanju segmenata ŠC-a i po čimbenicima korekcije ŠC-a. Za 20 jednostavnim slučajnim uzorkovanjem odabranih gospodarskih jedinica provedene su kvantitativne i kvalitativne analize postojećeg stanja otvorenosti. Budući da su analize ukazale na lošiju relativnu otvorenost gotovo svih gospodarskih jedinica, proveden je postupak unaprjeđenja primarne šumske prometne infrastrukture – planiranjem, odnosno postavljanjem nul linijskih poligona do razine vrlo dobre ili izvrsne otvorenosti. U svrhu unaprjeđenja mreže primarnih šumskih prometnica konstruiran je i model primarnog otvaranja šuma, provjeren na primjeru dvije gospodarske jedinice koje su sukladno sustavu procjene primarne relativne otvorenosti nedovoljno otvorene. Analize pogodnih sustava pridobivanja drva provedene su pomoću novodefiniranih modela, za 20 reprezentativnih gospodarskih jedinica u državnom vlasništvu (Hrvatske šume d.o.o.), temeljem njihovih terenskih i sastojinskih značajki. Iste su provedene u dva navrata: 1. Za postojeće stanje otvorenosti i 2. Za unaprijeđeno stanje otvorenosti. U tu svrhu odabrano je sljedećih 7 sustava pridobivanja drva: 1. Harvester – forvarder, 2. Harvester sa sidrenim vitlom – forvarder sa sidrenim vitlom, 3. Motorna pila – Forvarder, 4. Motorna pila – forvarder sa sidrenim vitlom, 5. Motorna pila – skider s vitlom, 6. Motorna pila – vučena šumska žičara i 7. Motorna pila – stupna kamionska žičara. Rezultati modela pridolaska sustava pridobivanja drva ukazuju na mogućnost primjene strojne sječe i izrade u gospodarskim šumama RH, kao i važnost tradicionalnog sustava pridobivanja drva, motorna pila – skider sa vitlom čiji udio pridolaska je osobito izražen u gospodarskim jedinicama bioklimata jelovih, bukovo-jelovih te smrekovih šuma. Osim toga, evidentan je pozitivan utjecaj otvaranja šuma na pridolazak visokomehaniziranih sustava pridobivanja drva.

Published
2021

28. Usporedba mogućnosti alata Blander i Autodesk Maya za 3D modeliranje

Author

Janeš, David and Slavuj, Vanja

Abstract

U ovome radu usporedit će se mogućnosti alata za 3D modeliranje: Blender i Autodesk Maya. U uvodnome dijelu definirat će se 3D modeliranje i opisati metode koje se često primjenjuju. U glavnom dijelu će se detaljno prikazati navedeni alati te u istima opisati postupak izgradnje modela srednje složenosti na konkretnom primjeru iz svakodnevnog života, čekiću. Na kraju rada dana je kritička usporedba dvaju korištenih alata te njihove prednosti i nedostatci.

Published
2020

30. Round Wood Waste and Losses

Author

Đuka, Andreja, primary, Sertić, Mirna, additional, Pentek, Tibor, additional, Papa, Ivica, additional, Janeš, David, additional, and Poršinsky, Tomislav, additional

Published
2020
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32. Terrain Classification for Timber Harvesting and Forest Accessibility

Author

Janeš, David, Poršinsky, Tomislav, Pentek, Tibor, Tomašić, Željko, Papa, Ivica, Đuka, Andreja, and Tolosana, Eduardo

Subjects
terrain trafficabilty, bioclimates, planning, GIS
Abstract

Different terrain conditions influence the type of machines and harvesting systems as well as designing and construction of forest roads. Vehicle mobility is the ability of a vehicle to move in terrain while performing its primary mission, while terrain trafficability is its property to allow the passage of a vehicle, where terrain conditions show their influence. From the standpoint of planning harvesting operations and forest accessibility on a strategic level, terrain slope is the most critical field parameter that directly affects the selection of the harvesting system. This paper deals with terrain classification for forestry operations in the Republic of Croatia which expands across three central European biogeographical regions – Continental, Alpine and Mediterranean – and therefore has a very high level of forest diversity comprised of 11 out of 14 European forest types. Terrain classification was based on ten forest bioclimates where each was analysed regarding 1) slope classes, 2) soil erosion risk classes, 3) soil moisture regimes 4) terrain ruggedness index (TRI) and 5) ground obstacles – stoniness. The research was based on commercial state and private forests on totally 1, 989, 647 ha. Bioclimates were as follows: 1. Subalpine dwarf pine forests 2. Subalpine spruce and beech forests 3. Mountainous fir, beech-fir and spruce forests 4. Sub-mountainous beech forests 5. Sessile oak forests of hilly terrain 6. Common oak and floodplain forests 7. Sub-Mediterranean mountainous beech and black pine forests 8. Sub-Mediterranean pubescent oak forests with hop-hornbeam 9. Sub-Mediterranean pubescent oak forests with oriental hornbeam 10. Mediterranean Aleppo pine and holm oak forests and maquis Analysis showed various conditions in each bioclimate. The most commercial species in national forestry, such as common and sessile oak, beech and fir were accumulated in five bioclimates (2–5) and had specific terrain conditions. Subalpine spruce and beech forests cover 34, 232 ha of the researched area. Soil moisture regime is entirely automorphic, and 56.06% of bioclimate is on intermediately rugged terrain. 72.60% of bioclimate has 51–90% stoniness coverage on the surface and 60.91% of forests are on terrain slopes above 34%, while 27.13% of forests are on slopes above 51%. On 78.21% of the surface, there is a moderate risk of erosion. Mountainous fir, beech-fir and spruce forests cover 185, 762 ha of the researched area. Soil moisture regime is on 99.88% of the surface automorphic, and the most of the growing stock is on slightly and intermediately rugged terrain. The share of stoniness per surface is high whereas 56.82% of these forests contain 51–90% of ground obstacles. At 67.75% of the surface, terrain slope is above 21%, while the most growing stock (26.30% of area) can be found on terrain slopes between 34 and 50%. Sub-mountainous beech forests cover 331, 099 ha of researched area. Soil moisture regime is on 94.54% of the surface automorphic, and the highest share of the growing stock (101–400m3/ha) is spread on a level, nearly level and slightly rugged terrain. Terrain ruggedness index showed slight changes regarding previously mentioned bioclimates and this change continues in term of ground obstacles. At 62.39% of the bioclimate share of stones on the surface is below 2%, however at 16.99% of forests stoniness is between 51-90%. Three slope classes prevail in these forests 1) terrain slopes between 11 and 20% at 75, 891 ha of bioclimate, 2) terrain slopes between 21 and 33% at 100, 874 ha of bioclimate and 3) terrain slopes between 34 and 50% at 79, 822 ha of bioclimate. At 41.08% of forests risk of erosion is low, while at 54.29% the risk is moderate. Sessile oak forests of hilly terrain cover 311, 679 ha of researched area. Soil moisture regime is at 77.50% of the surface automorphic while at 22.07% of the area pseudogley soil types were found. Terrain ruggedness index shows that 71.63% of bioclimate is on level terrain and 74.58% of these forests contain up to 2% coverage of stones on the surface. Terrain slope ranges from 11–20% at 33.05% of the area and from 21–33% at 29.29% of forests, while 64, 448 ha contain slopes above 34%. At 53.73% of the surface, soil erosion risk is low, but 39.82% show moderate erosion risk. Common oak and floodplain forests cover 288, 310 ha of researched area. The soil is highly influenced by the surface, underground and rainfall water and at 27.15% of surface amphigley soils can be found, at 26.70% of surface contain pseudogley soil, while alluvial, epigleic, hypogleic and semigleic soil can be found at 29.61% of the surface. Analysis showed that 99.54% of the surface TRI is level without ground obstacles (99.54% of forests contain up to 2% share of stoniness). Terrain slope is at 92.84% of the area up to 10%, and at 97.83% there is a low risk of soil erosion. Digital terrain model based on the input data will enhance planning of timber harvesting, forest accessibility (forest road route layouts) and stress the environmental aspect of given procedures in the highlight of terrain diversity, various stand conditions and different ways of forest management. The analysis was done on a national level, including almost 2 million hectares of state and private forests, of which 91.4% are commercial forests.

Published
2018

33. Energy Efficiency of Mechanized Thinning in Broadleaf Stand

Author

Pandur, Zdravko, Đuka, Andreja, Papa, Ivica, Bačić, Marin, Janeš, David, Vusić, Dinko, Radojčić Radovniković, Ivana, Jakovljević, Tamara, Petravić Tominac, Vlatka, Panić, Manuela, Stojaković, Renata, Erdec, Dina, Radošević, Kristina, Gaurina Sarček, Višnja, and Cvjetko Bubalo, Marina

Subjects
harvester, forwarder, energy return on investment
Abstract

Efficiency of timber harvesting systems is traditionally expressed in time and/or monetary values per unit of a product. Unit cost of production is still regarded as a main factor for selecting harvesting systems in the planning phase and for the evaluation of their efficiency. Rapid development of the renewable energy sector and bioenergy sector as its key part raised a question of bioenergy competitiveness when compared to energy produced from fossil fuels as well as from other renewables. At this point, when timber harvesting systems had to be analysed as energy production systems, unit of a timber product could no longer be the sole denominator for calculating the efficiency and novel research methods had to be applied. In this research, energy efficiency of mechanized timber harvesting by a harvester (Timberjack 1470D) – forwarder (Timberjack 1710D) system in an 80-year old broadleaf harvesting site was determined, and expressed as EROI (Energy Return On Investment). Field experiment consisted of time studies and measuring fuel consumption while other input data was gathered from own previous research in similar conditions or literature sources. System boundaries were set at the landing, i.e. roundwood delivered to the roadside is regarded as a system’s final product. Energy investment was calculated on PMH (Productive Machine Hour) level enabling the use of input parameters of cost calculations as well as expressing the results in the span of main factors (DBH and extraction distance) used in the productivity models. Energy investment of a harvester amounted to 1022.4 MJ/PMH (84% fuel ; 9% production of a machine ; 6% oil ; 1% tyres) and that of a forwarder to 529.9 MJ/PMH (75% fuel ; 16% production of a machine ; 5% oil ; 4% tyres). When expressed on a product level, energy investment of a harvesting system reached 130 MJ/m3 (for average DBH = 23 cm and average extraction distance of 360 m). Energy return for beech and hornbeam wood in fresh state (45% moisture content) is 9282 MJ/m3, thus the application of the investigated harvesting system under the conditions of the specified felling site results with EROI of 71.5. Furthermore, EROI is expected to range from 38 (for DBH 12.5 cm) to 102 (for DBH 42.5 cm) with the average extraction distance of 360 m ; and from 76 (for 100 m extraction distance) to 65 (for 800 m extraction distance) with the average DBH of 23 cm. Reduction of the moisture content to half of the initial value (by natural drying of energy wood) would increase the energy gain by 8%. But, in order to cover the EROI of the final energy product, system boundaries should be shifted to the end user. Energy investment calculation should cover the transportation and preferably explore different transformation processes (production of firewood in the household ; mechanized production of oven-ready chopped firewood and production of wood pellets).

Published
2018

34. Is Life Cycle Assessment In Forestry Still At Starting Position?

Author

Đuka, Andreja, Vusić, Dinko, Bačić, Marin, Janeš, David, Pandur, Zdravko, Papa, Ivica, and Borz, Stelian A.

Subjects
life cycle assessment, energy consumption, environmental management, wood products, environmental impact
Abstract

Life cycle assessment (LCA) is one of the most used tools for environmental management, but its application in forestry is still slow. Forestry and wood technology together produce vast amount of different wood products, but the production of timber as raw material is still not included often enough in the LCA process. Production steps have a significant influence on the environmental impact of wood products depending on machinery used, building and maintaining forest roads, management type (clear-cut, even-aged management or selective cut) etc. This paper will show past and present of LCA studies in forestry and its sections: 1) harvesting operations, 2) biomass and 3) forest infrastructure network construction and maintenance.

Published
2017

35. Kriteriji određivanja gustoće primarne šumske prometne infrastrukture – Primjeri najčešćih slučajeva

Author

Poršinsky, Tomislav, Đuka, Andreja, Papa, Ivica, Bumber, Zoran, Janeš, David, Tomašić, Željko, and Pentek, Tibor

Subjects
Gustoća primarne šumske prometne infrastrukture, osnovni/eleminacijski kriteriji, posebni/pro - storni kriteriji
Abstract

Pri svakom je planiranju, pa tako i pri planiranju mreže šumskih prometnica, vrlo važno poznavati postojeće stanje, odnosno imati detaljan i točan uvid u postojeću mrežu šumskih prometnica područja zahvata otvaranja šuma, što omogućuje registar šumske prometne infrastrukture. Želi li se valjano procijeniti kvantiteta postojeće šumske prometne infrastrukture (gustoća šumskih prometnica), potrebno je jasno i nedvosmisleno definirati kriterije određivanja gustoće postojeće šumske prometne infrastrukture. U hrvatskome šumarstvu, trenutno važeće kriterije za određivanja gustoće primarne šumske prometne infrastrukture definiraju »Tehnički uvjeti za gospodarske ceste« (Šikić i dr. 1989), koji su u sažetom obliku uključeni u Pravilnike o uređivanju šuma (NN 111/06, NN 141/08) te (NN 79/15). Spomenuti su kriteriji nedovoljno precizni i nejasni te šumarskim stručnjacima prepuštaju donošenje niza subjektivnih odluka. Kako bi se izbjegla/smanjila svaka subjektivnost, dobili objektivni podaci te omogućila usporedivost izračunate gustoće primarne šumske prometne infrastrukture različitih gospodarskih jedinica, prišlo se izradi potpuno novih kriterija koji će poslužiti za precizno, objektivno i transparentno određivanje gustoće primarne šumske prometne infrastrukture. Kriteriji su razvijeni i detaljno opisani u okviru Obrasca za izradu Elaborata učinkovitosti mreže šumskih prometnica – primarne šumske prometne infrastrukture, koji je sastavni dio Pravilnika o provedbi mjere M04 »Ulaganja u fizičku imovinu«, podmjere 4.3. »Potpora za ulaganja u infrastrukturu vezano uz razvoj, modernizaciju i prilagodbu poljoprivrede i šumarstva«, tipa operacije 4.3.3. »Ulaganje u šumsku infrastrukturu« iz Programa ruralnog razvoja Republike Hrvatske za razdoblje 2014. – 2020. (NN 106/15, 65/17). U radu su na ortosnimkama prikazani te združeni sa fotografijom (slikovni dio registra primarne šumske prometne infrastrukture iz studije slučaja) najčešći/karakteristični primjeri primjene kriterija pri određivanju gustoće primarne šumske prometne infrastrukture.

Published
2017

36. Usporedba podataka prikupljenih različitim metodama terenske izmjere pri rekonstrukciji šumske ceste

Author

Papa, Ivica, Pentek, Tibor, Janeš, David, Šerić, Tomislav, Vusić, Dinko, and Đuka, Andreja

Subjects
šumska cesta, rekonstrukcija, klasična i suvremena metoda, horizontalno i vertikalno razvijanje, poprečni presjeci, volumen zemljorada, šumska cesta, rekonstrukcija, klasična i suvremena metoda, horizontalno i vertikalno razvijanje, poprečni presjeci, volumen zemljorada
Abstract

Šumske su ceste jednostavni građevinski objekti koji tijekom cijele godine omogućuju stalan i nesmetan promet motornim vozilima u prvom redu pri izvođenju radova vezanih uz održivo gospodarenje šumama. Optimalna mreža primarnih šumskih prometnica, ako je pravilno raspoređena i položena, osigurava ispunjenje svih zadaća propisanih šumskogospodarskim planovima uz najmanje troškove i uz najveći učinak. Istraživanje je provedeno na šumskoj cesti »587 B1 004« stacionaže 15+20, 16 hm u gorskim prebornim šumama GJ Belevine, u Zalesini, Nastavno-pokusnom šumskom objektu Šumarskoga fakulteta Sveučilišta u Zagrebu. Primijenjene su dvije metode prikupljanja terenskih podataka pri izravnom trasiranju radi izrade glavnoga projekta rekonstrukcije spomenute šumske ceste. Prva, klasična metoda obuhvaćala je upotrebu mjernih uređaja teodolita DE-5A, nivelira Sokkia C330 i ostale mjerne opreme, dok je pri suvremenoj metodi prikupljanja terenskih podataka korištena radna stanica Sokkia Series 3030R. Prikupljeni terenski podaci obrađeni su u računalnom programu »Cesta«, a za statističku obradu podataka korišten je računalni program STATISTICA 8. Statističkom analizom podataka prikupljenih različitim metodama terenske izmjere ustanovljeno je kako između podataka koji su povezani uz horizontalno i vertikalno razvijanje trase šumske ceste »587 B1 004« ne postoji statistički značajna razlika. Statistički značajna razlika pojavljuje se pri usporedbi površine poprečnih presjeka, volumena zemljanih masa i elemenata kolničke konstrukcije, što se dovodi u izravnu vezu s različitim načinom prikupljanja terenskih podataka prilikom izmjere poprečnih presjeka.

Published
2017

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