Biogas är en förnyelsebar energikälla som tillverkas genom att organiskt material som matavfall bryts ner av mikroorganismer under anaeroba (syrefria) förhållanden. Regeringen har satt upp mål för en högre matavfallsutsortering vilket leder till ökad mängd tillgängligt substrat till biogasproduktion. Matavfallet som samlas in börjar brytas ner under tiden det transporteras och lagras. Syftet med studien var att undersöka hur länge matavfall lagras, ta fram ett representativt recept på ett genomsnittligt matavfall i Sverige och utvärdera hur mycket metanpotential som försvinner från matavfall med avseende på lagringstid, insamlingssystem (papper- och plastpåse) och lagringstemperatur (22°C och 6°C) genom laboratorieförsök. Den genomsnittliga lagringstiden för matavfall från villor och flerbostadshus i undersökningen var sex dagar. Ett recept för matavfall har tagits fram med hjälp av litteratursökning och modifiering av recept i Avfall Sveriges rapport U2010:10. Laboratorieförsöken visade att skillnaden i metanpotential mellan plast och papper var tydlig vid 22°C, då metanpotentialen sjunker, men obefintlig vid 6°C. För att uppnå maximal metangasproduktion från matavfall under den varma delen av året så är plastpåsar bättre då de har en mer konserverande effekt på matavfallet än papperspåsar. Detta kan relateras till att plast är tätare än papper och därför håller inne flyktiga ämnen. / Biogas is a renewable energy source that is produced when organic materials like food waste is degraded by microorganisms under anaerobic (oxygen-free) conditions. The Swedish Government has set goals for a higher sorting of food waste, leading to increased amounts of available substrate for biogas production. Collected food waste begin to break down during the time it is transported and stored. The purpose of this study was to investigate the length of the storage, produce a representative recipe for an average food waste in Sweden and evaluate how much methane potential is lost from food waste with respect to the storage time, collection method (paper or plastic bag) and storage temperature (22°C and 6°C) through laboratory tests. The average storage time of food waste from houses and apartment buildings in the survey was six days. A recipe for food waste has been developed with the help of literature search and modification of recipes in ‘’Avfall Sverige’’ report U2010:10. Laboratory tests showed that the difference in methane potential between the plastic and paper were clear at 22°C, with decreasing methane potential, but non-existent at 6°C. To achieve maximum methane production from food waste during the warmer part of the year, plastic bags are better because they have a preservative effect on the food waste. This can be related to the fact that plastic are denser than paper and therefore holds volatile compounds better.

Utvecklingen och framstegen av e-handelssystem har dominerat den elektroniska handeln de senaste åren. Problem som ofta förekommer är hur säker är hanteringen av konsumentensdata, specifik när den gäller det personliga metadata som användaren genererar ifrån sig när de handlar via nätet. Många företag och organisationer investerar mycket på att utöka tjänsterna för sina konsumenter med hjälp av marknadsstrategi företag-till-kund, men de flesta verksamheter som samlar in data har lite koll gällande konsekventa handlingar som förekommer med hanteringen av den personliga integriteteten, insamlingen av de personliga metadata och det rättsliga skyddandet av just denna typ av data. Arbetet tar fram utmaningar med hur personlig metadata hanteras och hur den skulle kunna verkställas till att användningen blir mindre problematisk. Arbetet hittade att utmaningen ligger mest dels inom samordningen mellan teknik och lag. IT-experterna måste specificera på vilket sätt ska metadata samlas in, hur det ska lagras och vad ska den användas till, medan de juridiska experterna måste kvalificeras ifall metadata ska behandlas som traditionella data eller om den ska få en särskild rättsordning. Andra fynd som insamling, lagring och användning av metadata togs även fram i detta arbete. / The development and progress of the e-commerce system has dominated electronic trade in recent years. Problems that often arise are how confident is the handling of consumer data, specifically regarding the personal metadata that the user generates when shopping through the net. Many companies and organizations are investing a great deal in expanding their consumer services using market strategy Business-to-Consumer (B2C), but most collecting data have little attention to consistent documents that occur with the management of personal privacy, collection of personal metadata and the legal protection of this type of data. This paper addresses challenges with how personal metadata is handled and how it can be implemented to make the use less problematic. Survey in this paper found that the challenge lies mostly in the coordination between technology and law. IT experts must specify how metadata should be collected, how it should be stored and what should it be used for, while legal experts must qualify if metadata is to be treated as traditional data or whether it will have a specific legal system. Other findings such as the collection, storage and usage of metadata were also featured in this work.

Sweden is heading towards a larger portion of renewable, weather dependent energy sources as a part of climate policy. To integrate such energy sources there is an increasing demand of flexibility in the Swedish electricity system. This further indicates a need to understand the rationality behind investments in flexibility resources, such as energy storage and demand response. The purpose of this study is to investigate whether the measurement Levelised Cost of Storage (LCOS) is reflecting the way Swedish actors reason about investments in flexibility resources. By qualitative interviews with actors and calculations of LCOS in seven different use cases the investment logic related to energy storage is analysed in a Swedish context. By doing so this study aims to form a basis of how to encourage an effective utilization of the values that flexibility resources can provide. Investments in energy storage and demand response technology are in studied use cases driven by soft values as goodwill, knowledge and comfort. Possible economic savings are often the rational argument for an investment, however, a greater benefit accrue to network operators, technology suppliers, and most of all, the electricity system. Regulations regarding network operators’ required rate of return, ownership and bid requirements on the Swedish power regulation market are currently not promoting a transformation to a completely renewable energy system, in which flexibility resources are seen as presumptions. Soft values and system values are difficult to quantify, which aggravates an understanding of the investment rationality regarding energy storage and demand response in a Swedish context. Several actors pointed out power, primary to energy, as the deficient resource, which increases the problem to assess when investments will occur by using LCOS methodology.

I den här rapporten presenteras och implementeras ett mer lagringseffektivt sätt att köra kod på mikrokontrollers. Det jämförs också med det traditionella sättet detta görs på. Metoden involverar en hopptabell och målet är att kunna köra större mängder kod än vad som kan lagras på mikrokontrollern. Utan att förlora för mycket prestanda.I slutändan finns det inget självklart svar på om systemet som implementerats är ett bra alternativ till traditionella applikationer. Fler faktorer än bara prestanda presenteras och måste beaktas när system implementeras. Den utvecklade prototypen introducerade en overhead på cirka 1%. Därför kunde slutsatsen dras att prototypen är ett rimligt alternativ (prestandamässigt) till det traditionella sättet att köra applikationer. / In this paper, a more storage efficient way of running code on microcontrollers is presented, implemented and compared against the conventional method. The method involves utilising a jump table and the objective is to be able to execute larger amounts of code than fits into the program memory of the microcontroller. Without loosing too much performance.In conclusion, there is no obvious answer to whether the implemented system is a viable alternative to traditional applications or not. More variables than just performance are brought up and must be considered when a system is implemen- ted. However, the developed prototype introduced a minor overhead of about 1%. It could therefore be concluded that the prototype is a viable alternative, to the conventional way of running applications, performance-wise.

Detta arbete fokuserar på utvecklingen av ett system för att noggrant övervaka laddningen av litium-jonbatterier. Genom att förebygga urladdning eller potentiella skador på batterier under lagring. Med användning av detta system kan livslängden på batterierna förlängas och en mer hållbar och effektiv energihantering kan uppnås. Att identifiera problem och avvikelser i battericellerna i realtid under lagring, kan snabba åtgärder vidtas för att minimera riskerna för skador och därmed förbättra prestanda och öka batteriernas livslängd. Säkerställning av batteridrivna system med en säker och hållbar drift, bidrar detta arbete till en mer effektiv användning av resurser.I detta arbete utvecklas ett system som övervakar en enskild cells SoC kontinuerligt för att säkerställa att denna inte laddas ur för mycket och skadas. Systemet utför också en kapacitetstest för att avgöra batteriets hälsotillstånd. Detta system ser också till att batteriernas laddningstillstånd hålls inom de rekommenderade nivåerna för att öka livslängd och prestanda. Först modelleras en Simulink-modell för detta ändamål och utifrån Simulink-modellen byggs ett system som övervakar battericellen i realtid och utför kapacitetstest om nödvändigt. Resultatet var framgångsrik och uppfyllde alla de förväntningar som författarna hade. Systemet övervakar cellen kontinuerligt, genom att hela tiden läsa av dess spänningen och få information om dess laddningstillstånd. Den utför också kapacitetstest och resultaten är som goda. Bättre val av komponenter kunde ha gjorts för att optimera och göra systemet mera noggrann vid beräkningar. Den största begränsningen var de begränsningar som Arduino Uno hade, som för lite minnesplats för kod och felavläsning av spänningen. Sammanfattningsvis har författarna uppnått de mål som de önskat med projektet och ser att behovet av sådana system kommer öka markant allteftersom elektrifieringen av samhället går framåt. / This work focuses on the development of a system to accurately monitor the state of charge of lithium-ion batteries, aiming to prevent discharge and potential damage during storage. By using this system, the lifespan of the batteries can be extended, and more sustainable and efficient energy management can be achieved. Identifying issues and deviations in battery cells in real-time during storage allows for prompt actions to minimize the risk of damage, thereby improving performance and increasing the battery’s lifespan. Ensuring the safe and sustainable operation of battery-powered systems, this work contributes to a more efficient utilization of resources. In this study, a system is developed to continuously monitor the state of charge of an individual cell, ensuring it is not excessively discharged and damaged. The system also performs capacity tests to assess the battery’s health condition. Additionally, the system ensures that the charging state of the batteries is maintained within recommended levels to enhance their lifespan and performance. Initially, a Simulink model was created for this purpose, and based on the Simulink model, a real-time battery monitoring system is built, capable of performing capacity tests whennecessary. The results were successful and met all the expectations of the authors. The system continuously monitors the cell by reading its voltage and gathering information about its charging state. It also performs capacity tests, yielding positive results. Better component selection could have been done to optimize and enhance the system’s accuracy in calculations. The main limitations encountered were related to the constraints of the Arduino Uno, such as limited memory and voltage reading inaccuracies. In conclusion, the authors have achieved their desired goals with this project and recognize that the demand for such systems will significantly increase as society moves toward electrification.

Fler svenskar vill konsumera mer inhemskt producerad fisk. Scandinavian Aquasystems odlar och försöker introducera fisken tilapia på svenska marknaden. Tilapia är en fisk som precis börjat göra intåg i Europa men är stor runtomkring resten av världen. En smakprofil som berättar hur länge produkten är sensoriskt tjänlig kan vara av hjälp. Denna undersökning syftade till att skapa en sensorisk smakprofil för fisken tilapia och till att se hur smakprofilen förändrades vid lagring i vakuumförpackning. För att skapa smakprofilen användes metoden QDA. Resultatet gav många egenskapsord var av vissa kunde klassificeras som färskhetsrelaterade och vissa som förskämningsrelaterade. Det kunde även konstateras att färsk, odlad tilapia har en antydan av saftigare och mer mjäll textur. Vid lagring finns en möjlighet att tilapia får en intensivare smak av dy och metall, samt en intensivare doft av dy. / A large amount of Swedes has a desire to consume more nationally produced fish. Scandinavian Aquasystems produces and tries to introduce tilapia into the Swedish market. As a fish, tilapia has just begun making ways into Europe but is already a big commodity around the rest of the world. In addition, a sensory profile which tells how long the product remains sensorially suitable could be of help. This study aimed to create a sensory profile and to study its inherent effects of vacuum packaging over time. In creating the sensory profile, a QDA method was used. The study resulted in a variance of different attributes which of some could be categorized as either fresh related or spoilage related. It was found that fresh, farmed tilapia carried an indication of having a juicier and more tender texture. With storage there is chance of tilapia getting a more intense flavor of mud and metal, as well as a more intense odor of mud.

<p>Superchilling is a method that can be used to prolong the shelf life of foods by partial freezing. Knowledge of the effects of this method on both the shelf life and quality of foods is important in order to find optimal processing and storage conditions and is of great importance both for the industry and for the consumers. Different raw materials of muscle foods were studied with the purpose of creating a basis for further improvements of both the process and the storage conditions. Products from the commercially important species pork (both roasts and rib steaks), Atlantic salmon (both vacuum packed and wrapped fillets) and Atlantic cod (vacuum packed fillets) were chosen to represent different muscle foods.</p><p>Based on both sensory and microbial evaluations, the superchilled storage improved shelf life of pork roasts from 2 to 16 weeks, and shelf life might even be further prolonged if temperature is kept more constant. The H2S-producing bacteria in superchilled cod fillets did not exceed the limit of consumption during the whole storage period of six weeks, while the microbial shelf life of the ice chilled fillets was estimated to be 8 days after processing.</p><p>Quality changes have been studied with focus on biochemical and physiochemical properties. One of the major goals in meat and fish processing is the ability to retain water and it was observed that drip loss was lower in superchilled samples compared to traditionally chilled samples in all species studied. However, the subsequent liquid loss was higher both in pork roasts and in cod fillets.</p><p>The extractability of protein was used as a tool to monitor protein denaturation. It was found that myofibrillar proteins denatured more easily during superchilled than during traditionally chilled storage both in salmon and in cod fillets. This was confirmed by electrophoresis in salmon. The amount of free amino acids were higher in cod than in salmon and increased more during superchilled storage than during ice chilled storage indicating exoproteolytic activity during storage. Activities of cathepsins B and B + L in salmon fillets were relatively stable during the storage period in all storage groups, demonstrating that these enzymes are not deactivated at the selected storage temperatures and may therefore lead to softening during subsequent chilled storage.</p><p>In superchilled samples of all species studied, white spots emerged on the product surface. However, the appearance of spots did not correspond either to higher drip loss or to higher microbial growth on surface of these samples. On the contrary, the total plate counts of superchilled samples were lower than of the other storage groups. This observation also applied to iron agar counts on cod fillets. These findings are interpreted as a strong indication of that the spots most likely were not of microbial origin.</p><p>The optimal superchilling process and storage conditions remains to be found for the products studied. From the present results it is reasonable to suggest that optimal storage temperature for the vacuum packed salmon fillets is found between the superchilled temperatures in the present experiments. The quality both of the pork roasts and the cod fillets would probably benefit from a storage temperature slightly closer to 0 °C than those studied. It can also be assumed that the control of the superchilling process is more essential to cod than to salmon and pork. In addition, the properties of the raw material are crucial in order to obtain high quality of products after processing and storage.</p> / Paper I-III are reprinted with kind permission from Elsevier, sciencedirect.com

Superchilling is a method that can be used to prolong the shelf life of foods by partial freezing. Knowledge of the effects of this method on both the shelf life and quality of foods is important in order to find optimal processing and storage conditions and is of great importance both for the industry and for the consumers. Different raw materials of muscle foods were studied with the purpose of creating a basis for further improvements of both the process and the storage conditions. Products from the commercially important species pork (both roasts and rib steaks), Atlantic salmon (both vacuum packed and wrapped fillets) and Atlantic cod (vacuum packed fillets) were chosen to represent different muscle foods. Based on both sensory and microbial evaluations, the superchilled storage improved shelf life of pork roasts from 2 to 16 weeks, and shelf life might even be further prolonged if temperature is kept more constant. The H2S-producing bacteria in superchilled cod fillets did not exceed the limit of consumption during the whole storage period of six weeks, while the microbial shelf life of the ice chilled fillets was estimated to be 8 days after processing. Quality changes have been studied with focus on biochemical and physiochemical properties. One of the major goals in meat and fish processing is the ability to retain water and it was observed that drip loss was lower in superchilled samples compared to traditionally chilled samples in all species studied. However, the subsequent liquid loss was higher both in pork roasts and in cod fillets. The extractability of protein was used as a tool to monitor protein denaturation. It was found that myofibrillar proteins denatured more easily during superchilled than during traditionally chilled storage both in salmon and in cod fillets. This was confirmed by electrophoresis in salmon. The amount of free amino acids were higher in cod than in salmon and increased more during superchilled storage than during ice chilled storage indicating exoproteolytic activity during storage. Activities of cathepsins B and B + L in salmon fillets were relatively stable during the storage period in all storage groups, demonstrating that these enzymes are not deactivated at the selected storage temperatures and may therefore lead to softening during subsequent chilled storage. In superchilled samples of all species studied, white spots emerged on the product surface. However, the appearance of spots did not correspond either to higher drip loss or to higher microbial growth on surface of these samples. On the contrary, the total plate counts of superchilled samples were lower than of the other storage groups. This observation also applied to iron agar counts on cod fillets. These findings are interpreted as a strong indication of that the spots most likely were not of microbial origin. The optimal superchilling process and storage conditions remains to be found for the products studied. From the present results it is reasonable to suggest that optimal storage temperature for the vacuum packed salmon fillets is found between the superchilled temperatures in the present experiments. The quality both of the pork roasts and the cod fillets would probably benefit from a storage temperature slightly closer to 0 °C than those studied. It can also be assumed that the control of the superchilling process is more essential to cod than to salmon and pork. In addition, the properties of the raw material are crucial in order to obtain high quality of products after processing and storage. / Paper I-III are reprinted with kind permission from Elsevier, sciencedirect.com

This report is a thesis in mechanical engineering with a focus on development assistance. The thesis was carried out in collaboration with the Gombe Youth Development Organization. The task was to develop an adequate system to collect, purify and store water in the two rural villages Gombe and Kayunga in Uganda. The system takes into account local weather, water quality, population, water consumption and types of water sources. The final system has a low manufacturing cost, simple maintenance, low operating cost, is electrical independent and can be manufactured and repaired with local available components. The report presents various types of sources of water and purification of varying suitability for these conditions. The report also includes operation and maintenance manual and an approximate budget. The result of this work is a combined system of rainwater harvesting, flocculation and one "up flow" rapid sand filter with built-in storage tank. Given that only rainwater collection is not enough to cover a normal sized family of 10 individuals consumption of water, due to this water from natural sources is also used. / Den här rapporten är ett examensarbete i maskinteknik med inriktning mot bistånd. Examensarbetet utfördes i samarbete med Gombe Youth Development Organization. Uppgiften bestod i att ta fram ett lämpligt system för att samla in, rena och lagra vatten i de två byarna Gombe och Kayunga på Ugandas landsbygd. Systemet tar hänsyn till lokalt väder, vattenkvalité, population, vattenkonsumtion och typer av vattenkällor. Det slutliga systemet har låg tillverkningskostnad, är lätt att underhålla, har låg driftskostnad, är inte beroende av elektricitet och kan tillverkas och repareras av lokalt tillgängliga komponenter. Rapporten presenterar olika typer av insamlingskällor av dricksvatten och metoder för rening med varierande lämplighet för dessa förutsättningar. Rapporten innefattar även drift- och underhållsmanual och en ungefärlig budget. Resultatet av arbetet är ett system kombinerat av regnvatteninsamling, flockning och ett ”up flow” snabbt sandfilter med inbyggd förvaringstank. Med tanke på att endast regnvatteninsamling inte räcker till för att täcka behovet för en normalstor familj på 10 personer, kommer även vatten från naturliga källor även att användas.

The demand for large scale storage of carbon dioxide (CO2) grows stronger as incentives to reduce greenhouse gas emissions are introduced. Geological storage sites such as depleted oil and gas reservoirs, unminable coal seams and deep saline water-saturated aquifers are a few of many possible geological storage sites. Geological formations offer large scale storage potential, hidden locations and are naturally occurring world wide. A disadvantage is the difficulty to investigate the properties of storage material over large areas. Reservoir simulation studies addressing issues of heterogeneous reservoirs are growing in number. There is still much to investigate however this study adds to the field by investigating the significance of the heterogeneity in hydraulic conductivity based on core sample data. The data was received from the main CO2 injection site Heletz, Israel in the European Union Seventh Framework Programme for research and technological development (EU FP7) project MUSTANG (CO2MUSTANG, 2011-03-13). By developing models using iTOUGH2/ECO2N, the aim of this study is to contribute to a better understanding of how the average permeability, variance in permeability and spatial correlation of the reservoir properties affect the distribution of CO2 within the deep saline aquifer target layer. In this study a stochastic simulation approach known as the Monte Carlo method is applied. Based on core sample data, geostatistical properties of the data are determined and utilized to create equally probable realizations where properties are described through a probability distribution described by a mean and variance as well as a constructed semivariogram. The results suggest that deep saline aquifers are less storage effective for higher values of average permeability, variance in permeability and spatial correlation. The results also indicate that the Heletz aquifer, with its highly heterogeneous characteristics, in some extreme cases can be just as storage effective as a deep saline aquifer ten times as permeable consisting of homogeneous sandstone. / Incitament för minskningar av växthusgaser har på senare tid ökat efterfrågan för storskalig lagring av koldioxid (CO2). Geologiska lagringsplatser som exploaterade olje- och gasreservoarer, svårutvunna kollager och djupt belägna salina akvifärer är exempel på potentiella lagringsplatser. Sådana geologiska formationer erbjuder storskalig lagring, dold förvaring och är naturligt förekommande världen över. Dock finns det stora svårigheter i att undersöka de materiella egenskaperna för hela lagringsområden. Simuleringsstudier som hantera frågor gällande reservoarers heterogenitet växer i antal. Det finns fortfarande mycket kvar att undersöka och denna studie bidrar till detta forskningsområde genom att undersöka betydelsen av heterogenitet i hydraulisk konduktivitet för spridningen av koldioxid med hjälp av uppmätt brunnsdata. Data erhölls från lagringsplatsen Heletz i Israel som är den huvudsakliga lagringplatsen i projektet MUSTANG är en del av den Europeiska Unionens sjunde ramprogram för forskning och teknisk utveckling (EU FP7), (CO2MUSTANG, 2011/3/13). Genom att utveckla modeller med hjälp av programvaran iTOUGH2/ECO2N är syftet med denna studie att bidra till en bättre förståelse för hur den genomsnittliga permeabilitet, varians i permeabilitet samt rumslig korrelation av reservoaregenskaper påverkar fördelningen av CO2 i den djupa saltvattenakvifären Heletz. Denna studie använde sig av stokastisk simulering genom att tillämpa Monte Carlo-metoden. Med hjälp av tidigare uppmätt brunnsdata kunde geostatistiska egenskaper bestämmas för att skapa ekvivalent sannolika realiseringar. De geostatistiska egenskaperna beskrevs med en sannolikhetsfördelning genom medelvärde och varians samt ett konstruerat semivariogram. Resultaten tyder på att djupa saltvattenakvifärer är mindre lagringseffektiva vid högre värden av genomsnittlig permeabilitet, varians i permeabilitet och rumslig horisontell korrelation. Resultaten visar även att Heletz akvifär, med dess mycket heterogena egenskaper, i extrema fall kan vara lika lagringsineffektiv som en djupt belägen saltvattenakvifär med tio gånger högre genomsnittlig permeabilitet.