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Ultrasonic standing wave (USW) particle manipulation has during the last two decades matured into a valuable tool to combine with microfluidics. Acoustophoresis, migration through sound, is the result of the acoustic radiation force acting on particles suspended in an acoustic field. The acoustic radiation force magnitude is proportional to the acoustic energy density, frequency and particle size. The acoustic radiation force has successfully been implemented in particle washing, size-based separation, mechanical phenotype-based cell separation and trapping applications. The force magnitude and direction also depend on the difference between the mechanical properties of the fluid and particle. In the first part of this thesis, we show that the mechanical properties of dead cells are a function of the surrounding fluid which was used to acoustically separate dead and viable cells in a density modulated medium.The non-invasive and biocompatible acoustic radiation force has also been used in trapping applications tailored towards tissue modelling and engineering. One of the explored models is the multicellular tumor spheroid (MTCS) which is a spherical aggregate of tumor cells. The MCTS models a solid tumor and is increasingly used to replace regular 2D cell culture techniques in cancer research and drug screening pipelines. The majority of this thesis will be dedicated to the formation and culture of scaffold-free MCTSs using the acoustic radiation force in silicon and glass microwells. We have developed two multiwell microplate designs where either a 100 MCTSs in a single compartment or 576 MCTSs divided into 16 compartments can be formed in parallel using USWs. By using a sequential cell seeding method it is possible to control the MCTS structural architecture and create core-shell MCTSs. The glass bottom in the microwells in combination with efficient clearing protocols also enabled whole MCTS imaging which was utilized to characterize the cell cycle and the volumetric parameters of the nuclei within the MCTSs using image analysis. Finally, we used the 16 chamber multiwell microplate to investigate the drug response in MCTSs from 4 different cell lines simultaneously and evaluate the NK cell cytotoxic response towards MCTSs in presence of different treatments. Ultraljudsbaserad partikelmanipulation har under de senaste två decennierna utvecklats till ett värdefullt verktyg inom mikrofluidik. Akustofores, migrationgenom ljud, är resultatet av den akustiska strålningskraften som verkar på partiklar suspenderade i ett akustiskt fält. Den akustiska strålningskraftens storlek är proportionell mot den akustiska energitätheten, frekvensen samt partikelstorleken och har framgångsrikt implementerats i partikeltvätt, storleksbaserad separation, mekanisk fenotypbaserad cellseparation och aggregeringsapplikationer. Kraftens magnitud samt riktning beror även på skillnaden mellan vätskans och partikelns mekaniska egenskaper. I den första delen av denna avhandling visar vi att de mekaniska egenskaperna hos döda celler är en funktion av den omgivande vätskan. Konceptet användes för att akustiskt separera döda och levande celler i ett densitetsmodulerat medium.Den icke-invasiva och biokompatibla akustiska strålningskraften har också använts i aggregeringstillämpningar skräddarsydda för vävnadsmodellering. En av de utforskade modellerna är den multicellulära tumörsfäroiden (MCTS) som är ett sfäriskt aggregat av tumörceller. MCTSen modellerar en solid tumör och används i allt högre grad för att ersätta vanliga 2D-cellodlingstekniker i cancerforskning och läkemedelsscreening. Huvuddelen av denna avhandling kommer att ägnas åt bildandet och odlingen av MCTS:er användandes den akustiska strålningskraften i kisel- och glasmikrobrunnar. Vi har utvecklat två mikrobrunnsbaserade mikrochip där antingen 100 MCTS:er i ett enda fack eller 576 MCTS uppdelat i 16 fack kan bildas parallellt med ultraljud. Genom att använda en sekventiell cellsåddningsmetod är det möjligt att kontrollera MCTS-arkitekturen och skapa kärn-skal MCTS:er. Mikrobrunnarnas glasbotten i kombination med effektiva transparensinducerande protokoll möjliggjorde även MCTS-avbildning som användes för att karakterisera cellcykeln och de volymetriska parametrarna för cellkärnor i MCTS:er med hjälp av bildanalys. Slutligen använde vi mikrochippetmed 16 kamrar för att undersöka läkemedelsresponsen i MCTS:er från fyra olika cellinjer samt utvärdera NK-cellens cytotoxiska respons mot MCTS:er i närvaro av olika läkemedel.

Denna projektrapport beskriver arbetet med att utveckla en broms som tillbehör till företaget Jemtlanders fjällpulka. Syftet med projektet var att ge så stor kundnytta som möjligt, vilket skulle uppnås genom ett pulkatillbehör som hjälpte användaren att bromsa i utförsåkning. Produktutvecklingsarbetet skulle i förlängningen göra utförsåkning säkrare för företagets pulkaanvändande kunder. Målen var att över en tio veckor lång period leda ett produktutvecklingsarbete från fasen förstudie, via konceptgenerering och detaljkonstruktion, fram till en prototyp. Det levererade resultatet skulle ta hänsyn till användares åsikter och behov genom bland annat en studie där befintliga användare fick dela både sina förväntningar och synpunkter på en tidig funktionsprototyp. Arbetet genererade en detaljerad produkt-beskrivning, en tillverkad prototyp och ett underlag för att ta vidare produkten till de slutgiltiga faserna i produktutvecklingsprocessen. Arbetet lade stor tyngd på prototyper och fälttester. Resultatet presenterade ett produktkoncept som kunde uppfylla önskade kriterier inklusive de som studien med användare adderade. Bromsen utformades som en vickande ram monterad på framsidan av pulkans skrov. När pulkan åker i kapp användaren skapas en tryckande kraft genom skaklarna. Den kraften får bromsramen att rotera då den fäster i pulkan och skaklarna på två parallella gångjärnsleder. På nedsidan av ramen sticker armar ut som når ner i snön vid rotationen och bromsar. Genom linor som löper längs skaklarna mellan pulka och användare kan ramens bromskraft enkelt styras. Produktutvecklingsprocessen ledde arbetet till ett resultat som uppfyllde målen genom en utvecklad produkt och en tillverkad första prototyp redo att testas i fält. This project report presents the work of developing a brake as an accessory to the company Jemtlander's pulk system. The purpose of the project was to provide as much customer value as possible, which would be achieved through a sled accessory that helped the user to brake when downhill skiing. The product development work would in the long run make downhill skiing safer for the company's sled-using customers. The goals were to lead a product development work from a pre-study phase over a ten-week period, via concept generation and detailed design to a prototype. The delivered result took into account the users' opinions and needs through, among other things, a study in which a group of existing users shared both their expectations and views on an early functional prototype. The project generated a detailed product description, a manufactured prototype and a basis for taking the product to the final phases of the product development process. The work placed great emphasis on prototypes and field tests. The results presented a product concept that could meet desired criteria including the needs that the study with regular users added. The brake was designed as a rocking frame mounted on the front of the sled's hull. When the sled catches up with the user, a compressive force is created through the poles. The force causes the brake frame to rotate as it attaches to the sled and the poles on two different hinge joints. On the bottom part of the frame, braking arms protrude which reach down into the snow during rotation. Through ropes that run along the poles between the sled and the user, the braking force of the frame can be easily controlled. The product development process led the work to a result that met the goals by a developed product and a manufactured first prototype ready to be tested in the field. Betyg 2021-08-09

Microsized hexagonal gallium nitride pyramids show promise as next generation Light Emitting Diodes (LEDs) due to certain quantum properties within the pyramids. One metric for evaluating the efficiency of a LED device is by studying its Light Extraction Efficiency (LEE). To calculate the LEE for different pyramid designs, simulations can be performed using the FDTD method. Maximizing the LEE is treated as a black-box optimization problem with an interpolation method that utilizes radial basis functions. A simple heuristic is implemented and tested for various pyramid parameters. The LEE is shown to be highly dependent on the pyramid size, the source position and the polarization. Under certain circumstances, a LEE over 17% is found above the pyramid. The results are however in some situations very sensitive to the simulation parameters, leading to results not converging properly. Establishing convergence for all simulation evaluations must be done with further care. The results imply a high LEE for the pyramids is possible, which motivates the need for further research.

Detta är en rapport som beskriver utvecklingen av ett produktkoncept som är tänkt att ersätta Weda:s SD-enhet. SD-enheten är ett munstycke som kan tillverkas från 1𝑚 upp till 10𝑚 brett i bockad plåt och sitter installerad på en drivenhet. Denna ersättare av SD-enheten ska göras mer anpassningsbar efter olika bassängstorlekar och billigare i tillverkningskostnader. Baserat på kundkrav, problemställning och till följd av en utvecklingsprocess togs det fram fem koncept där samtliga stöds av grundläggande fakta, teoretiska tillverknings och monterings aspekter samt flödessimuleringar. Dessa fem koncept sattes emot varandra i en sållnings matris för att sedan gå vidare med ett koncept som vidareutvecklades med hjälp av projektverktyg som QFD och DFA. Slutligen utfördes en laboration med en prototyp med syfte att undersöka och stärka projektets beräkningar. Avslutningsvis analyseras resultaten som ställts upp mot projektets mål och kundkrav för att värdera om projektet har lyckats eller ej. This report describes the development of a product concept that’s supposed to replace Weda's SD-System. The SD-System suction nozzle is scalable from 1 𝑚 up to 10 𝑚 wide out of bent sheet metal and is installed to a driving unit. The new pool cleaner attachment concept is supposed to be more modular to fit different basins and be cheaper in manufacturing. Based on customer requirements, the problems description and the development process, five concepts were developed. All the concepts are supported by basic facts, theoretical manufacturing and assembly aspects as well as flow simulations. These five concepts were opposed to each other in a screening matrix and then proceeded with a concept that was further developed using project tools such as QFD and DFA. Finally, a laboratory exercise was performed with a prototype and the purpose of investigating and strengthening the project's calculations. Finally, the results that are set against the project's objectives and customer requirements are analyzed to evaluate whether the project has succeeded or not.

PROBLEM DEFINITION: E-recruiters have two customer segments to look after, job seekers and employers. Value for these two segments is created by the e-recruiter when communication and information between employer and job seeker is facilitated. Job seekers evaluate e-recruiters based on the value proposition that is offered. This study examines what components of the value proposition generate value for job seekers and how the value proposition is communicated through channels. PURPOSE OF THE STUDY: The study aims to investigate which factors that have a major impact on job seekers in their choice of job portal, as well as how e-recruiters' value proposition and business model should be designed and communicated to match these customer needs. METHODOLOGY: In this case study value creation for job seekers has been studied by interviewing students as representatives for job seekers. The response from the students have then been compared to a company that provides a job portal. The use of an interview guide has ensured that all the respondents have received similar questions. In order to compare theory with collected data an operationalization has been used to create a consistent structure for interpreting the respondents replies. CONCLUSIONS: E-recruiters currently focus a great deal of resources on developing a powerful and competitive value proposition. A great value proposition is important, but it must be focused on the most important functions for job seekers -a large pool of jobs and simplicity in searching and filtering jobs. One area that is not prioritized sufficiently high is how the value proposition should be communicated to job seekers. E-recruiters must focus more on how and where contact is made with job seekers, where our study shows that digital channels and word of mouth-effects are important areas to work on.

NK cells are large granular lymphocytes that patrol the body for defect or virally infected cells. The migration of natural killer (NK) cells is critical for the detection and elimination of aberrant cells such as tumor- and virally infected cells. If a NK cell stumbles upon a target, i.e. an aberrant or stressed cell, the NK cell has the ability to kill the target cell. Limitations in the efficiency of NK cells, such as limited migration speed, and the finite number of target cells that can be killed by one NK cell, leaves the immune system vulnerable to diseases. However it has been shown that NK cell populations are heterogeneous, and from one host to another the overall efficiency of NK cells may vary. If the most efficient NK cells could be isolated from a cell population and cultivated, great numbers of high performing NK cells could then possibly be reintroduced to a body and be used to fight maladies such as cancer and HIV. In an attempt to bring us closer to these possibilities, and further examine the characteristics of NK cells, a high quality master was manufactured and used for microcontact printing. This project has focused on how NK cell migration is affected by cell structure and whether NK cells can be directed along a pattern to provide a situation where NK cell migration speed can be measured rigorously. This was done by using microcontact printing to create micro patterns of proteins that mimics the geometry of the NK cells migrating phenotype. This report will give a description of the master fabrication process and it will be shown that NK cells can be influenced to move straighter by interacting with a microcontact printed pattern of proteins. Furthermore our results will conclude that NK cell migration speed is not affected significantly by the microcontact printed proteins.

This candidate thesis contains the possibility of expand the Swedish photovoltaic market through photovoltaic cooperatives and a photovoltaic exchange. In the current situation there is a lot of problems with production of electricity from photovoltaic, that’s why we show some possibilities how to avoid these. To understand the problem with photovoltaic produced electricity we first give you a background. We show how to expand the Swedish photovoltaic market by describing how a photovoltaic cooperative and photovoltaic exchange could work in Sweden. It have been confirmed from our market research that the interest of photovoltaic cooperative and exchange is high. To find out how profitable photovoltaic is in Sweden, have three projections been made. These have been done to show how the price per kWh affect depending the size of the power plant. With the help of these results it can be decided which of the projected plants who is the most profitable for given conditions. The photovoltaic power plant that uses the Swedish grand scheme optimal and has the maximum size is the most profitable today. The thesis has been divided into five sections, background, projections, cooperative, photovoltaic exchange and market research. The thesis is limited to Swedish conditions and is based on information from literature, technical reports and interviews.

This paper presents some findings from the piloting phase of our research on students’ thinking about physical processes imbedded in a number of technical and natural phenomena. We mean by “thinking physics” how students use language of physics, i.e. appropriate terminology, concepts and modelling tools.