Yes / This study investigates the physical and mechanical properties of 12 biomass wood pellet samples utilised in a power generation, focusing on their implications for energy release and carbon emissions during combustion. Through comprehensive analysis involving bulk density measurements, compression tests, moisture analysis, calorimetry and controlled burning experiments, significant correlations among key properties are identified. Pellets with densities above 1100 kg/m3 demonstrate superior mechanical durability and strength, achieving maximum strengths of 0.6 to 0.8 kN with durability exceeding 99.4%. Optimal moisture content, typically between 6 and 7% is crucial for maximising density, bulk density, mechanical durability and fracture resistance, ensuring robust pellet structure and performance. The research underscores the impact of pellet dimensions, highlighting those longer lengths, > 12 mm enhance durability, while larger diameters > 8 mm exhibit reduced durability. Elemental analysis focusing on calcium, silicon and potassium plays a critical role in predicting and managing combustion system fouling, potentially reducing operational costs. Moreover, the study emphasises the significant influence of oxygen levels during combustion on CO2 emissions, achieving optimal results with moisture content in the 7–8% range for maximum higher heating value (HHV). The moisture content in the 14–15% range represents the lowest CO2 emission. The findings underscore the intricacy of the system and the interplay of parameters with one another. In accordance with the priority of each application, the selection of parameters warrants careful consideration. / This work was supported by the UK Carbon Capture and Storage Research Community (UKCCSRC) and the Engineering and Physical Sciences Research Council (EPSRC) through the UKCCSRC Flexible Funding Call 2022.

A Síndrome da Imunodeficiência Adquirida (AIDS) é uma doença de amplo espectro de manifestações, sendo razão de preocupação para qualquer autoridade sanitária. A terapêutica da AIDS é complexa sendo utilizados vários medicamentos, diversas vezes ao dia. Deste modo, objetivou-se o desenvolvimento de formas farmacêuticas sólidas como comprimidos tamponados mastigáveis (CTM), comprimidos com revestimento gastro-resistentes (CRGR) e pellets (PEL) para a veiculação de didanosina (ddl). Seis especialidades farmacêuticas na forma de CTM foram estudadas quanto ao perfil de dissolução, pH do meio e capacidade neutralizante ácida (CNA). Formulações teste de CTM foram propostas visando obter CNAs e perfis de dissolução adequados. Também foram testadas formulações de comprimidos e de pellets para posterior revestimento com filme gastro-resistente derivado do ácido metacrílico. Os ensaios de dissolução das amostras de CTM revelaram diferenças nas características de liberação do fármaco. Também foram observadas diferenças relacionadas a CNA. As formulações de CTM propostas apresentaram, na maioria dos casos, adequados perfis de dissolução e CNA. As formulações CRGR que receberam revestimento gastro-resistente apresentaram perfis de dissolução de ddl adequados, entretanto os comprimidos testados intumesceram em meio ácido, indicando descontinuidade do filme polimérico sobre os comprimidos. Testes para a produção de pellets veiculando ddl mostraram-se adequados quanto à morfologia e dissolução do fármaco, o mesmo sendo observado após o revestimento com filme gastro-resistente. / The Acquired Immune Deficiency Syndrome (AIDS) is a disease that manifests itself in a myriad of ways. Because of this, the condition has been subject of concern to all sanitary authorities. The treatment of AIDS is complex and many types of medicine are used, many times a day. The objective of the present study was to develop solid pharmaceutical dosage forms such as buffered chewable tablets (CTM), gastro-resistant coating tablets (CRGR) and pellets (PEL) for the loading of didanosine (ddl). Six pharmaceutical specialties in the form of CTM were studied so as to identify the profile of the dissolution, the pH of the environment, and the neutralizing acid capacity (CNA). The use of CTM tests formulations was proposed with the objective of obtaining adequate CNA and dissolution profiles. Different compositions of tablets and pellets were tested for a later addition of gastro-resistant film derived from the methacrylic acid. The experiments on the dissolution of the sample of CTM showed differences in the characteristic of the release of the substance. Differences related to the CNA were also observed. The formulations of the CTM proposed showed to have, in the most number of the cases, both adequate dissolution behavior and CNA. The formulations of the CRGR that had received the gastro-resistant coating showed adequate profile of ddl dissolution; the tested tablets, however, swelled in the acid environment, therefore indicating a lack of continuity of the polymeric film over the tablets. The tests for the production of pellets showed adequate results as to its morphology and dissolution of ddl. The same was observed after coating the pellets with gastro-resistant film.

A Síndrome da Imunodeficiência Adquirida (AIDS) é uma doença de amplo espectro de manifestações, sendo razão de preocupação para qualquer autoridade sanitária. A terapêutica da AIDS é complexa sendo utilizados vários medicamentos, diversas vezes ao dia. Deste modo, objetivou-se o desenvolvimento de formas farmacêuticas sólidas como comprimidos tamponados mastigáveis (CTM), comprimidos com revestimento gastro-resistentes (CRGR) e pellets (PEL) para a veiculação de didanosina (ddl). Seis especialidades farmacêuticas na forma de CTM foram estudadas quanto ao perfil de dissolução, pH do meio e capacidade neutralizante ácida (CNA). Formulações teste de CTM foram propostas visando obter CNAs e perfis de dissolução adequados. Também foram testadas formulações de comprimidos e de pellets para posterior revestimento com filme gastro-resistente derivado do ácido metacrílico. Os ensaios de dissolução das amostras de CTM revelaram diferenças nas características de liberação do fármaco. Também foram observadas diferenças relacionadas a CNA. As formulações de CTM propostas apresentaram, na maioria dos casos, adequados perfis de dissolução e CNA. As formulações CRGR que receberam revestimento gastro-resistente apresentaram perfis de dissolução de ddl adequados, entretanto os comprimidos testados intumesceram em meio ácido, indicando descontinuidade do filme polimérico sobre os comprimidos. Testes para a produção de pellets veiculando ddl mostraram-se adequados quanto à morfologia e dissolução do fármaco, o mesmo sendo observado após o revestimento com filme gastro-resistente. / The Acquired Immune Deficiency Syndrome (AIDS) is a disease that manifests itself in a myriad of ways. Because of this, the condition has been subject of concern to all sanitary authorities. The treatment of AIDS is complex and many types of medicine are used, many times a day. The objective of the present study was to develop solid pharmaceutical dosage forms such as buffered chewable tablets (CTM), gastro-resistant coating tablets (CRGR) and pellets (PEL) for the loading of didanosine (ddl). Six pharmaceutical specialties in the form of CTM were studied so as to identify the profile of the dissolution, the pH of the environment, and the neutralizing acid capacity (CNA). The use of CTM tests formulations was proposed with the objective of obtaining adequate CNA and dissolution profiles. Different compositions of tablets and pellets were tested for a later addition of gastro-resistant film derived from the methacrylic acid. The experiments on the dissolution of the sample of CTM showed differences in the characteristic of the release of the substance. Differences related to the CNA were also observed. The formulations of the CTM proposed showed to have, in the most number of the cases, both adequate dissolution behavior and CNA. The formulations of the CRGR that had received the gastro-resistant coating showed adequate profile of ddl dissolution; the tested tablets, however, swelled in the acid environment, therefore indicating a lack of continuity of the polymeric film over the tablets. The tests for the production of pellets showed adequate results as to its morphology and dissolution of ddl. The same was observed after coating the pellets with gastro-resistant film.

Master of Science / Department of Animal Sciences and Industry / Micheal J. Brouk / Supplemental phosphorus (P) in varying forms and sources: pellet (PELLET), meal (MEAL), liquid (LIQUID) and corn dried distiller’s grains with solubles (DDGS) were compared in twelve multiparous Holstein cows producing approximately 43 kg of milk (115 [plus minus] 55 DIM) in a 4x4 Latin square with 21d periods. PELLET and MEAL diets contained monocalcium phosphate with a wheat middlings carrier, and the LIQUID contained ammonium polyphosphate in a cane molasses base. The DDGS supplied an organic P source. Cows were blocked by parity, DIM and milk production and randomly assigned to treatments. Data were analyzed using the MIXED model procedure of SAS. Phosphorus intakes of 116, 116, 119 and 118 g/d were similar for PELLET, MEAL, LIQUID and DDGS diets, respectively. Cows consuming the LIQUID diet experienced greater sugar intakes (P<0.001). Fat intake was lower (P<0.001) for the PELLET, MEAL and LIQUID diets compared to the DDGS diet (1.14, 1.12, 1.07 and 1.36 kg/d, respectively). NEL intake was similar for all treatments (P=0.55). Milk yield differences (P=0.05) occurred with the DDGS diet yielding the most milk (34.6, 35.4, 34.1 and 36.5 kg/d). No differences resulted for either milk fat (P=0.26) or milk protein (P=0.33) percentages or for daily lactose production (P=0.22). Excretion of P in feces tended (P=0.07) to differ between treatments (67.4, 66.3, 57.5 and 60.0 g/d) resulting in a trend (P=0.10) for greater P retention in diets excreting less P. Secretion of P in milk did not differ (P=0.51) between treatments. Differences (P=0.04) occurred in P concentration between diets (0.47, 0.47, 0.49 and 0.47%), but the amount of P fed was not different (P=0.83). With similarities for DMI and P concentration in refusals (P=0.21) it may be deduced that sorting of the P supplement did not occur. These data show that supplemental P sources do not affect DMI or P intake, however P source resulted in slight differences in P utilization, but it was not related to sorting of the diet. Utilizing DDGS showed similar responses to inorganic P mineral supplements with favorable production yields making it an adequate substitute for mineral sources of P.

Waste-to-energy has become an attractive alternative to landfills. One concern in this development is the release of pollutants in the combustion process. The binder enhanced d-RDF pellets satisfy the requirements of environmental acceptance, chemical/biological stability, and being storeable. The acid gas emissions of combusting d-RDF pellets with sulfur-rich coal were analyzed by ion chromatography and decreased when d-RDF pellets were utilized. The results imply the possibility of using d-RDF pellets to substitute for sulfur-rich coal as fuel, and also substantiate the effectiveness of a binder, calcium hydroxide, in decreasing emissions of SOx. In order to perform the analysis of the combustion sample, sampling and sample pretreatment methods prior to the IC analysis and the first derivative detection mode in IC are investigated as well. At least two trapping reagents are necessary for collecting acid gases: one for hydrogen halides, and the other for NOx and SOx. Factors affecting the absorption of acid gases are studied, and the strength of an oxidizing agent is the main factor affecting the collection of NOx and SOx. The absorption preference series of acid gases are determined and the absorption models of acid gases in trapping reagents are derived from the analytical results. To prevent the back-flushing of trapping reagents between impingers when leak-checking, a design for the sampling train is suggested, which can be adopted in sample collections. Several reducing agents are studied for pretreating the sample collected in alkali-permanganate media. Besides the recommendation of the hydrogen peroxide solution in EPA method, methanol and formic acid are worth considering as alternate reducing agents in the pretreatment of alkaline-permanganate media prior to IC analysis. The first derivative conductivity detection mode is developed and used in IC system. It is efficient for the detection and quantification of overlapping peaks as well as being applicable for non-overlapping peaks.

In Sweden, there are about 0.5 million single-family houses that are heated by electricity alone, and rising electricity costs force the conversion to other heating sources such as heat pumps and wood pellet heating systems. Pellet heating systems for single-family houses are currently a strongly growing market. Future lack of wood fuels is possible even in Sweden, and combining wood pellet heating with solar heating will help to save the bio-fuel resources. The objectives of this thesis are to investigate how the electrically heated single-family houses can be converted to pellet and solar heating systems, and how the annual efficiency and solar gains can be increased in such systems. The possible reduction of CO-emissions by combining pellet heating with solar heating has also been investigated. Systems with pellet stoves (both with and without a water jacket), pellet boilers and solar heating have been simulated. Different system concepts have been compared in order to investigate the most promising solutions. Modifications in system design and control strategies have been carried out in order to increase the system efficiency and the solar gains. Possibilities for increasing the solar gains have been limited to investigation of DHW-units for hot water production and the use of hot water for heating of dishwashers and washing machines via a heat exchanger instead of electricity (heat-fed appliances). Computer models of pellet stoves, boilers, DHW-units and heat-fed appliances have been developed and the parameters for the models have been identified from measurements on real components. The conformity between the models and the measurements has been checked. The systems with wood pellet stoves have been simulated in three different multi-zone buildings, simulated in detail with heat distribution through door openings between the zones. For the other simulations, either a single-zone house model or a load file has been used. Simulations were carried out for Stockholm, Sweden, but for the simulations with heat-fed machines also for Miami, USA. The foremost result of this thesis is the increased understanding of the dynamic operation of combined pellet and solar heating systems for single-family houses. The results show that electricity savings and annual system efficiency is strongly affected by the system design and the control strategy. Large reductions in pellet consumption are possible by combining pellet boilers with solar heating (a reduction larger than the solar gains if the system is properly designed). In addition, large reductions in carbon monoxide emissions are possible. To achieve these reductions it is required that the hot water production and the connection of the radiator circuit is moved to a well insulated, solar heated buffer store so that the boiler can be turned off during the periods when the solar collectors cover the heating demand. The amount of electricity replaced using systems with pellet stoves is very dependant on the house plan, the system design, if internal doors are open or closed and the comfort requirements. Proper system design and control strategies are crucial to obtain high electricity savings and high comfort with pellet stove systems. The investigated technologies for increasing the solar gains (DHW-units and heat-fed appliances) significantly increase the solar gains, but for the heat-fed appliances the market introduction is difficult due to the limited financial savings and the need for a new heat distribution system. The applications closest to market introduction could be for communal laundries and for use in sunny climates where the dominating part of the heat can be covered by solar heating. The DHW-unit is economical but competes with the internal finned-tube heat exchanger which is the totally dominating technology for hot water preparation in solar combisystems for single-family houses. / <p>QC 20100916</p>

Call number: LD2668 .T4 1986 F87 / Master of Science / Biology

[pt] O presente trabalho visa o desenvolvimento de um sistema automático de identificação do Grau de Maturação de pelotas de minério de ferro, envolvendo técnicas de microscopia digital e processamento e análise digital de imagens. As pelotas de minério de ferro, juntamente com o sínter e o minério granulado, constituem uma das matérias-primas básicas no processo de produção do ferro primário. Numa das etapas de sua produção, as pelotas adquirem diferentes características microestruturais, os chamados Graus de Maturação, que influenciam diretamente seu comportamento nos processos de redução. Sendo assim, a caracterização microestrutural constitui-se em uma importante etapa de controle de qualidade do material. A evolução da microestrutura de pelotas específicas para altos-fornos foi dividida em quatro classes: A, B, C e D. A partir das micrografias obtidas por microscópio ótico, foram extraídos atributos capazes de descrever características intrínsecas de cada classe (ou Grau de Maturação), posteriormente utilizados para treinar um classificador automático. Para tentativas de otimização do processo, foram utilizadas 3 técnicas para redução de dimensionalidade (Busca exaustiva do conjunto com a melhor taxa de acerto, Análise de Componentes Principais e Análise Discriminante Linear de Fisher), e testados 3 tipos de classificadores (Quadrático, Mahalanobis e Linear). A maior taxa de acerto global obtida foi acima de 90 por cento. Este resultado indica que a metodologia desenvolvida mostrou-se efetiva para a classificação automática do Grau de Maturação de pelotas de minério de ferro de alto-forno. / [en] The present work aims to develop an automatic system to identify the maturation degree of iron ore pellets, involving techniques of microscopy and digital image processing. Iron ore pellets, as well as sinter and lump ore, are the basic iron-bearing burden used in ironmaking. In one of the steps of their production, the pellets acquire different microstructural characteristics, the socalled Maturation Degree, which influences directly in the reduction processes. Thus, microstructural characterization is an important step in quality control of the material. The microstructure evolution of pellets for blast furnaces was divided into four classes: A, B, C and D. Attributes that describe intrinsic characteristics of each class were extracted from optical microscope images and were used to train an automatic classifier. Three dimensionality reduction techniques were tested to optimize the classification system: exhaustive search, Principal Component Analysis and Fisher’s Linear Discriminant Analysis. Three types of classifiers were tested (Quadrático, Mahalanobis and Linear). The highest global success rate was above 90 per cent. This indicates that this methodology is effective for automatic classification of the Maturation Degree in blast furnace pellets.

Inom EU finns mål på att sänka utsläppen med 40% till år 2030. I Sverige står bygg och fastighetssektorn för cirka 21% av Sveriges totala utsläpp. För att lyckas nå EU:s klimatmål måste en konvertering till förnybara uppvärmningskällor ske. Region Gotland ansvarar idag för över 500 000m2 fastigheter. Många använder idag pellets till uppvärmning. Pellets ses som klimatneutralt och släpper därför inte ut mer koldioxid än vad trädet plockat upp. Ett problem som uppstår då pelletspannorna kräver underhåll och leveranser. Flera av Region Gotlands fastigheter ligger flera mil iväg från både leverantör och underhållspersonal vilket ökar kostnader och miljöpåverkan än mer. En av dessa fastigheter, brandstationen i Öja, ligger till grund för denna studie. Då det finns flera fastigheter med liknande förutsättningar kan rapporten användas som underlag för dessa. Studien undersöker ifall en konvertering från pelletspannan till en värmepump kan sänka kostnaderna och bidra till lägre utsläpp. Vid en konvertering till värmepump sänks systemtemperaturerna från 80/60 till 55/45 vilket kan skapa problem för befintliga radiatorer, rör och pumpar. Radiatorernas och rörens kompatibilitet med nya temperaturerna under söks därför i studien men pumpar utelämnas för en framtida studie. Med hjälp av transmissionsberäkningar och en formel baserad på grad dagar och tidigare energiförbrukning beräknades ett värmebehov för fastigheten på 23,8 kW den kallaste dagen på året. Med detta kunde tre värmepumplösningar tas fram. Samtliga lösningar innefattar även en ny ackumulatortank då den nuvarande är över 40 år gammal och har ett flertal brister. Med optimering av uppvärmningssystemet genom att sänka temperaturen i de fläktvärmda rummen till 15 grader kan värmebehovet sänkas med 4kW. En undersökning gällande installation av solfångare har även gjorts, där det inte visade sig lönsamt med dagens tappvarmvattenbehov.  Efter de dimensioneringar som gjorts framkommer även att två rörslingor behöver bytas, men att ett eventuellt radiatorbyte lämnas till efter en konvertering för att se om dessa behöver bytas. Undersökningarna visar även att de befintliga fläktvärmarna är överdimensionerade och inte behöver bytas. Utsläppsberäkningar visar att utsläppen kan minskas med 2565 kg CO2 eq per år vid en eventuell konvertering. Payoffmetoden har använts för att visa att de tre lösningarna har en mycket kort återbetalningstid mellan 3,9 år för luft/vattenvärmepumpar från CTC till 4,7 år för Thermias bergvärmelösning. Med hjälp av LCC kalkyler har lösningarna livstidskostnad tagits fram. Ställt mot den be fintliga pelletspannan uppgår besparingen till 879 000kr för Thermias lösning – 966 000kr för CTC:s lösning med en kalkylränta på 1,5%. Slutsatsen är därför att en konvertering till värmepump bör ske för att spara både ekonomiskt men även för att minska utsläppen. / One of EU’s climate goals is to reduce the greenhouse gas emissions by 40% by the year of 2030. In Sweden the “building and real estate sector” stands for 21% of Sweden’s total pollution of greenhouse gas emissions. To reach EU’s goals by 2030 there must be a transformation to renewable sources for use in the heating of real estates. Region Gotland manages over 500 000 m2 of estates. Many of which uses pellet as the source of heating. This heating alternative requires regular deliveries of material and maintenance. Many of the estates in the care of Region Gotland are far away from both the supplier and maintenance team which creates great transport costs and gas emissions. The fire sta- tion in “Öja” is one of them and is the one used in this study. As there are many similar buildings the results here can be used as a foundation for those estates. This study is exploring if a conversion from pellet to a heating pump can lower the expenses and greenhouse gas emissions. By changing to a heat- ing pump from a pellet boiler the temperatures are reduced from 80/60°C to 55/45 °C in the system. This may cause problem with radiators, pumps and pipes. Because of this, radiators and pipes will also be inves- tigated, but pumps will be left out for another study. The heat needed to increase the temperature in the building to 21 °C at a DVUT of -8,7 °C was calculated using transmission losses calculations and a formula based on “graddagar” and earlier energy uses by the estate, to 23,8 kW. Based on the calculated heat, three heating pump solutions were created, all of whom included a new water heater with storage tank. The old storage tank is over 40 years by age and therefore has many short- comings. Using calculations to optimize the heat usage, the heat needed can be re- duced by 4kW at DVUT by lowering the temperature to 15 °C in the fan heated area of the building while still being within the laws of the Swe- dish work environment authority. An investigation was made to see if solar collectors could be used to heat the domestic hot water in the estate. The results showed that in this case it wouldn’t be economically justifiable due to low energy cost with a new heating pump. The calculations done for pipes and radiators showed that two pipes must be replaced but that the radiators are mostly fine with the new tempera- tures. A replacement of the radiators should be left till after the conver- sion. Calculations on the fan heaters showed that there is no need to re- place these. Calculations on greenhouse gas emissions showed that the emissions can be reduce by 2565 kg CO CO2-eq each year if the pellet boiler is replaced by a heating pump. The Pay-off method and LCC calculations was used to show the profita- bility in the three heating pump solutions. The Pay-off time for the solu- tions ranged from CTC’s air to water heating pumps at 3,9 years to 4,7 years for Thermia’s geothermal heating pump. The LCC calculations showed that changing to a heat pump could generate a saving of 879 000 SEK for Thermia’s solution to 966 000 SEK for CTC’s solution. The conclusion is therefore that the pellet boiler should be changed to a heating pump to save money and reduce the greenhouse gas emissions.

Este trabalho trata da obtenção e caracterização de cerâmicas do sistema supercondutor Bi:Pb:Sr:Ca:Cu:O. O pó cerâmico foi feito por dois processos, mistura de óxidos/carbonatos e co-precipitação de oxalatos, com o objetivo de se estabelecer o procedimento mais favorável ao aparecimento da fase de temperatura critica de 110K. A caracterização do pó precursor foi feita através das técnicas de Plasma Indutivamente Acoplado (ICP), Picnometria, Sedigrafia, Difração de Raios X e Microscopia Eletrônica de Varredura. Na etapa de sinterização do pó estudamos, paralelamente a sinterização convencional, uma técnica alternativa de aplicação de corrente elétrica simultaneamente à ação da temperatura com o objetivo de acelerar a reação de formação e promover, possivelmente, uma maior fração da fase de mais alta temperatura critica. Ao final do processamento as amostras foram caracterizadas estruturalmente, por difração de raios X, e quanto às propriedades elétrica (resistividade elétrica) e magnética (susceptibilidade magnética). Na análise comparativa das características elétricas e estruturais das pastilhas obtidas convencional e quimicamente não observamos diferenças significativas entre elas. No entanto as medidas de susceptibilidade magnética mostraram uma grande diversificação de fases com temperaturas criticas abaixo de 110K, para a pastilha obtida por co-precipitação de oxalatos. Também verificamos que a fase 2223 encontra-se, nessa amostra, em maior proporção do que na pastilha proveniente de pó convencional. O processo alternativo de sinterização promoveu algumas alterações no comportamento da resistividade elétrica do material / This work is about the obtaining and characterizing pellets of the Bi:Pb:Sr:Ca:Cu:O system. The powder was prepared by two processes: oxide/carbonate mixture and oxalate co-precipitation. These two processes were used in order to establish the most favorable process to the 110 K phase formation. The characterization techniques were Inductively Coupled Plasma, Picnometry, Sedigraphy, X Ray Diffraction and SEM. The sinterization was made by conventional and an alternative techniques. The alternative one consists in applying electrical current simultaneously to the temperature action. The expectation was that this technique would accelerate the reactions and consequently, to promote higher volume fraction of the 110K phase. The pellets were structural, electrical and magnetically characterized by X Ray Diffraction, SEM, electrical resistivity and magnetic susceptibility. In the analysis of the electrical and structural characterization of the pellets made by both processing methods, we could not find any difference between them. But, the magnetization measurements indicated that there are numerous phases with critical temperature below 110 K, in addition a higher fraction of 2223 phase, in the pellet made by co-precipitation of oxalates. The alternative sintering process promoted a few alterations in the behavior of the electrical resistivity as a function of the applied temperature