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Spent nuclear fuel is received at a storage facility in heavily shielded casks transported by either rail or by truck. Once at the storage facility, the casks are inspected, emptied, decontaminated, and reshipped. Allied-General Nuclear Services' (AGNS) nuclear fuel reprocessing plant in Barnwell, South Carolina, is constructed but not yet licensed for spent nuclear fuel storage or reprocessing. Recently, however, AGNS was granted funds by the Department of Energy to prepare the necessary procedural and regulatory paperwork in order that the Fuel Receiving and Storage Station (FRSS) of the plant can be licensed by 1985. In this paper, the activities involved in the receiving an unloading of casks at the Barnwell FRSS is simulated by computer using IBM's program software package, General Purpose Simulation System (GPSS). The GPSS model is developed and verified, and steady-state output statistics are achieved. Also, several sensitivity analyses are performed such as, changes in expected arrival schedules and decision policies, and changes to the physical characteristics of the existing FRSS to monitor the effect of these changes in the existing system.

Fuel burnup calculations provide material concentrations and intrinsic neutron and gamma source strengths as a function of irradiation and cooling time. Detailed, full-core 3D burnup calculations are critical for nuclear fuel management studies, including core design and spent fuel storage safety and safeguards analysis. For core design, specifically during refueling, full- core pin-wise, axially-dependent burnup distributions are necessary to determine assembly positioning to efficiently utilize fuel resources. In spent fuel storage criticality safety analysis, detailed burnup distributions enable best-estimate analysis which allows for more effective utilization of storage space. Additionally, detailed knowledge of neutron and gamma source distributions provide the ability to ensure nuclear material safeguards. The need for accurate and efficient burnup calculations has become more urgent for the simulation of advanced reactors and monitoring and safeguards of spent fuel pools. To this end, the Virginia Tech Transport Theory Group (VT3G) has been working on advanced computational tools for accurate modeling and simulation of nuclear systems in real-time. These tools are based on the Multi-stage Response-function Transport (MRT) methodology. For monitoring and safety evaluation of spent fuel pools and casks, the RAPID (Real-time Analysis for Particle transport and In-situ Detection) code system has been developed. This dissertation presents a novel methodology and algorithm for performing 3D fuel bur- nup calculations, referred to as bRAPID- Burnup with RAPID . bRAPID utilizes the existing RAPID code system for accurate calculation of 3D fission source distributions as the trans- port calculation tool to drive the 3D burnup calculation. bRAPID is capable of accurately and efficiently calculating assembly-wise axially-dependent fission source and burnup dis- tributions, and irradiated-fuel properties including material compositions, neutron source, gamma source, spontaneous fission source, and activities. bRAPID performs 3D burnup calculations in a fraction of the time required by state-of-the-art methodologies because it utilizes a pre-calculated database of response functions. The bRAPID database pre-calculation procedure, and its automation, is presented. The ex- isting RAPID code is then benchmarked against the MCNP and Serpent Monte Carlo codes for a spent fuel pool and the U.S. Naval Academy Subcritical Reactor facility. RAPID is shown to accurately calculate eigenvalue, subcritical multiplication, and 3D fission source dis- tributions. Finally, bRAPID is compared to traditional, state-of-the art Serpent Monte Carlo burnup calculations and its performance will be evaluated. It is important to note that the automated pre-calculation proceedure is required for evaluating the performance of bRAPID. Additionally, benchmarking of the RAPID code is necessary to understand RAPID's ability to solve problems with variable burnups distributions and to asses its accuracy. / Ph. D. / In a nuclear reactor, the energy released from a fission reaction, the splitting of an atomic nucleus into smaller parts, is harnessed to generate electricity. Nuclear reactors rely on fuel, typically comprised of uranium oxide (UO₂). While the reactor is operating and the fuel is being used, or “burned”, for power production it is undergoing numerous nuclear reactions, including fission, and radioactive decays which alter the material composition. Knowing the time evolution of fuel as it is burned in the reactor, i.e., concentration of isotopes and sources of radiation, is critical. Nuclear reactor designers and operators use this information to optimize power production and perform safety analysis of used nuclear fuel. By performing fuel burnup calculations, material concentrations and radiation source strengths are obtained as a function of time in an operating nuclear reactor. Using traditional computational techniques, these calculations are extremely time consuming and, for certain problems, can be difficult to obtain an accurate solution. Ideally, a reactor designer would like to know the three-dimensional (3D) distribution of material compositions and sources; however this level of detail would require an excessive amount of calculation time, therefore simplified models and assumptions are used. For the design of the new generation of nuclear reactors, and monitoring and safeguards analysis, this level of detail will be required in lieu of the availability of experimental facilities which do not currently exist. This dissertation presents a novel methodology and algorithm for performing accurate 3D fuel burnup calculations in real-time, referred to as bRAPID (Burnup with RAPID). bRAPID utilizes an existing nuclear software, RAPID (Real-time Analysis for Particle transport and In-situ Detection), developed in the Virginia Tech Transport Theory Group (VT3G), which has been shown to accurately solve time-independent nuclear calculations in significantly less time than traditional approaches. bRAPID is capable of accurately calculating 3D material and source distributions as a function of time in an operating nuclear reactor, and requires significantly less time and computational resources than traditional approaches. To ensure that bRAPID is relatively easy to use, a number of automated routines have been developed and are presented. RAPID is benchmarked against the traditional code systems MCNP (Monte Carlo N-Particle) and Serpent, both of which are widely used in the nuclear community, for a spent fuel storage pool and the U.S. Naval Academy subcritical nuclear reactor facility. RAPID is shown to accurately calculate system parameters (eigenvalue and subcritical multiplication factor) and 3D fission source distributions. Finally, bRAPID is compared to the traditional burnup approach, using the Serpent code system. bRAPID is shown to accurately calculate system parameters and 3D material and source distributions in significantly less time than the traditional approach.

Various fuel cycles for a sodium-cooled, subcritical, fast reactor with a fusion neutron source for the transmutation of light water reactor spent fuel have been analyzed. All fuel cycles were 4-batch, and all but one were constrained by a total fuel residence time consistent with a 200 dpa clad and structure materials damage limit. The objective of this study was to achieve greater than 90% burn up of the transuranics from the spent fuel.

A geological repository for spent nuclear fuel (SNF) and an associated encapsulation facility will be built in Sweden.  The encapsulation facility is planned to be in operation in 2025 and it will be the last place where verifying safeguards measurements of SNF can be performed. It is not clear what types of measurements that will be performed, because such requirements are not yet posed by national and international authorities and inspecting organizations. This report describes the objective and most recent results of a master thesis project, whereby a few existing non-destructive assay techniques for verifying SNF are selected for a review. The study focuses on the verifying ability of different techniques, or system of techniques in relation to the requirement that may be put on the future encapsulation plant. In addition, possible needs for future simulations and measurements are discussed. The work is done as a collaboration between Uppsala University in Sweden and Los Alamos National Laboratory in the USA.

Förbrukat kärnbränsle är mycket radioaktivt och behöver därför lagras i djupa geologiska förvar i tusentals år innan det säkert kan återföras till naturen. På grund av de långa lagringsperioderna görs säkerhetsanalyser av de djupa geologiska förvaren. Under säkerthetsanalyserna görs upplösningsexperiment på förbrukat kärnsbränsle för att utvärdera konsekvenserna av att grundvatten läcker in i bränslet vid barriärbrott. Dessa experiment är både dyra och tidskrävande, varför beräkningsmodeller som kan förutsäga förburkat kärnbränsles upplösningsbeteende är önskvärda. Denna avhandling fokuserar på att samla in tillgängliga experimentella data från upplösningsexperiment för att uppdatera och utöka en databas. Med hjälp av databasen har upplösningsbeteendet för varje radionuklid utvärderats och jämförts med tidigare kunskap från befintlig litteratur. Även om det var svårt att vara avgörande om beteendet hos element där en begränsad mängd data fanns tillgänglig, motsvarar de upplösningsbeteenden som hittats för olika radionuklider i denna avhandling inte bara tidigare studier utan ger också ett verktyg för att hantera och jämföra förbrukat kärnbränsles upplösningsdata från olika utgångsmaterial, bestrålningshistorik och betingeleser under upplösning. Dessutom gjorde sammanställningen av en så stor mängd experimentella data det möjligt att förstå var framtida experimentella ansträngningar bör fokuseras, exempelvis finns det en brist på data under reducerande förhållanden. Dessutom utvecklades och kördes maskininlärningsmodeller med hjälp av Artificial Neural Network (ANN), Random Forest (RF) och XGBoost-algoritmer med hjälp av databasen, varefter prestandan utvärderades. Prestanda för varje algoritm jämfördes för att få en förståelse för vilken modell som presterade bäst, men också för att förstå om dessa typer av modeller är lämpliga verktyg för att förutspå förbrukat kärnbränsles upplösningsbeteende. Den bäst presterande modellen, med träning och test R2 resultat nära 1, var XGBoost-modellen. Även om XGBoost hade en hög prestanda, drogs slutsatsen att mer experimentell data behövs innan maskininlärningsmodeller kan användas i verkliga situationer. / Spent nuclear fuel (SNF) is highly radioactive and therefore needs to be stored in deep geological repositories for thousands of years before it can be safely returned to nature. Due to the long storage times, performance assessments (PA) of the deep geological repositories are made. During PA dissolution experiments of SNF are made to evaluate the consequences of groundwater leaking into the fuel canister in case of barrier failure. These experiments are both expensive and time consuming, which is why computational models that can predict SNF dissolution behaviour are desirable.  This thesis focuses on gathering available experimental data of dissolution experiments to update and expand a database. Using the database, the dissolution behaviour of each radionuclide (RN) has been evaluated and compared to previous knowledge from existing literature. While it was difficult to be conclusive on the behaviour of elements where a limited amount of data was available, the dissolution behaviours found of different radionuclides in this thesis not only correspond to previous studies but also provide a tool to manage and compare SNF leaching data from different starting materials, irradiation history and leaching conditions. Moreover, the compilation of such a large amount of experimental data made it possible to understand where future experimental efforts should be focused, i.e. there is a lack of data during reducing conditions. In addition, machine learning models using Artificial Neural Network (ANN), Random Forest (RF) and XGBoost algorithms were developed and run using the database after which the performances were evaluated. The performances of each algorithm were compared to get an understanding of which model performed best, but also to understand whether these kinds of models are suitable tools for SNF dissolution behaviour predictions. The best performing model, with training and test R2 scores close to 1, was the XGBoost model. Although XGBoost, had a high performance, it was concluded that more experimental data is needed before machine learning models can be used in real situations.

<p>Pivski trop čini približno 85% od ukupnih sporednih proizvoda proizvodnje piva, i dostupan je po veoma niskim cenama tokom čitave godine. Pivski trop ima veliku perspektivu za primenu u biotehnologiji i proizvodnji visoko vrednih proizvoda. Jedna od veoma ekolo&scaron;ki i ekonomski isplativih alternativa je upotreba pivskog tropa u proizvodnji mlečne kiseline, jer se poslednjih par decenija uočava intenzivan rast potražnje za mlečnom kiselinom. Mlečna kiselina je najvažnija hidroksikarbonska kiselina &scaron;iroko rasprostranjena u prirodi, sa velikom primenom u prehrambenoj, farmaceutskoj, tekstilnoj i hemijskoj industriji i industriji prerade kože.<br />Cilj istraživanja ove doktorske disertacije je ispitivanje primene pivskog tropa u proizvodnji mlečne kiseline. Prvo je izvr&scaron;ena optimizacija enzimske hidrolize pivskog tropa u cilju dobijanja &scaron;to je moguće veće koncentacije redukujućih &scaron;ećera neophodne za mlečno-kiselu fermentaciju. Hidrolizat pivskog tropa je dobijen enzimskom hidrolizom dodatkom komercijalnih enzima za razgradnju skroba i celuloze. Parametri čiji je uticaj na efikasnost enzimske hidrolize ispitanu su: pH vrednost, temperatura hidrolize i količina dodatih enzima. Nakon &scaron;to su određeni najbolji uslovi razgranje pivskog tropa, dobijeni postupak hidrolize je primenjen u proizvodnji hidrolizata pivskog tropa koji je kori&scaron;ćen u mlečno-kiselim fermentacijama.<br />Nakon toga je ispitana mlečno-kisela fermentacija sa dva proizvodna mikoorganizma. Kao proizvodni mikroorganizmi u mlečno-kiselim fermentacijama primenjena su dva soja bakterija mlečne kiseline: Lactobacillus fermentum PL-1 i Lactobacillus rhamnosus ATCC 7469. Ispitan je uticaj dodatka različitih koncentracija ekstrakta kvasca (0,5-5,0%) uz korekciju pH vrednosti tokom fermentacije sa dodatkom kalcijum-karbonata. U zavisnosti od udela L-(+)- i D-(-)-mlečne kiseline koje nastaju tokom fermentacije izabran je proizvodni mikroorganizam koji proizvodi vi&scaron;e L-(+)-mlečne kiseline.<br />U daljim ispitivanjima je ispitan uticaj korekcije pH pomoću natrijum-hidroksida kao i dodatak različitih koncentracija ekstrakta kvasca (0,5-5,0%) i redukujućih &scaron;ećera (2,7; 5,4 i 8,1%) u hidrolizatu pivskog tropa na mlečno-kiselu fermentaciju pomoću odabranog soja bakterija mlečne kiseline. Na osnovu dobijenih rezultata izabrana je najbolja koncentracija redukujućih &scaron;ećera i ekstrakta kvasca koji će se koristiti u daljim istraživanjima.<br />Takođe je ispitana i mogućnost zamene skupog ekstrakta kvasca i glukoze sa obnovljivim sirovinama, kao &scaron;to su pivski kvasac, džibra i bistra džibra.<br />Ispitan je uticaj dodatka različitih koncentracija pivskog kvasca (0,5-5,0%), džibre (5-20%) i bistre džibre (5-50%) pre fermentacije kao i dodatak bistre džibre u dolivnoj fermentaciji, na mlečno-kiselu fermentaciju hidrolizata pivskog tropa.<br />Ispitan je i dolivni postupak fermentacije hidrolizata pivskog tropa dodatkom glukoze, glukoze i ekstrakta kvasca i sladovine. Takođe je ispitana mogućnost izvođenja vi&scaron;e uzastopnih fermentacija sa imobilisanim ćelijama odabranog soja bakterija mlečne kiseline u kalcijum-alginatu.<br />Na osnovu eksperimentalnih rezultata zaključujeno je da je dodatak kalcijum-karbonata imao pozitivan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. Sa dodatkom kalcijum-karbonata povećali su se utro&scaron;ak redukujućih &scaron;ećera, koncentracija i prinos mlečne kiseline i vijabilnost ćelija L. fermentum i L. rhamnosus. Ekstrakt kvasca i kalcijum-karbonat su imali značajan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. U fermentacijama sa L. fermentum najveći prinos ukupne mlečne kiseline (44%) je postignut sa dodatkom 5,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. U fermentacijama sa L. rhamnosus najveći prinos ukupne mlečne kiseline (98%) i L-(+)-mlečne kiseline (96%) je ostvaren u fermentaciji sa dodatkom 2,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. Na osnovu rezultata odlučeno je da se u daljim ispitivanjima mlečno-kisele fermentacije hidrolizata pivskog tropa kao proizvodni mikoorganizam koristi L. rhamnosus.<br />Primenom natrijum-hidroksida za korekciju pH je skratila fermentaciju za 48 sati a ostvareno je i značajno povećanje zapreminske produktivnosti L-(+)-mlečne kiseline (za 200%, povećanje sa 0,21 na 0,63 g/l&middot;h-1). Korekcija pH u svim daljim istraživanjima je vr&scaron;ena sa dodatkom natrijum-hidroksida.<br />U mlečno-kiselim fermentacijama sa različitim početnim koncentracijama redukujućih &scaron;ećera (2,7; 5,4 i 8,1%) i sa dodatkom različitih koncentracija ekstrakta kvasca (0,5-5,0%), najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 91,29% i 1,69 g/l&middot;h-1, kao i vijabilnost ćelija L. rhamnosus od 9,7&middot;109 CFU/ml ostvareni su u fermentaciji sa početniom koncentracijom redukujućih &scaron;ećera od 5,4% i dodatkom 5,0% ekstrakta kvasca.<br />Na osnovu ostvarenih rezultata u istraživanjima sa dodatkom džibre i dodacima tokom fermentacije kao i u fermentacijama sa imobilisanim ćelijama je kori&scaron;ćen hidrolizat pivskog tropa sa početnom koncentracijom redukujućih &scaron;ećera od 5,4%.<br />U mlečno kiseloj fermentaciji sa dodatkom pivskog kvasca najveći prinos L-(+)-mlečne kiseline (89,01%) i zapreminska produktivnost (0,89 g/l&middot;h-1) L-(+)-mlečne kiseline su ostvareni u fermentaciji sa dodatkom 5,0% pivskog kvasca i korekcijom početne koncentracije redukujućih &scaron;ećera na 5,0%. Na osnovu rezultata utvrđeno je da se može izvr&scaron;iti delimična ili potpuna zamena ekstrakta kvasca pivskim kvascem uz značajno smanjenje cene podloge za mlečno-kiselu fermentaciju, bez značajnog smanjenja efikasnosti mlečno-kisele fermentacije.<br />U mlečno-kiseloj fermentaciji sa dodatkom džibre i bistre džibre najveć koncetracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline od 31,03 g/l, 86,15% i 0,93 g/l&middot;h-1, ostvareni su u fermentaciji sa dodatkom 50% bistre džibre. Najvi&scaron;a koncentracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline ostvareni u dolivnoj fermentaciji sa dodatkom glukoze i bistre džibre tokom mlečno-kisele fermentacije su iznosili su 48,02 g/l, 87,82% i 0,96 g/l&middot;h-1.<br />U fermentacijama sa dodatkom nutritijenata tokom mlečno-kisele fermentacije najveća vrednost koncetracije, prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline od 116,08 g/l, 93,32% i 2,04 g/L&middot;h-1, su ostvarene u fermentaciji sa dodatkom glukoze i ekstrakta kvasca tokom fermentacije. Na osnovu rezultata utvrđeno je da se dolivni postupak fermentacije može koristiti u cilju povećanja efikasnosti mlečno-kisele fermentacije.<br />Izvr&scaron;ena je imobilizacija ćelija L. rhamnosus u kalcijum-alginatu uz izuzetno visoku vijabilnost (1010 CFU/ml). Imobilisane ćelije L. rhamnosus su uspe&scaron;no kori&scaron;ćene u tri mlečno-kisele fermentacije. Prinos L-(+)-mlečne kiseline i zapreminska produktivnost su u sve tri fermentacije bili izuzetno visoki, pri čemu su najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 95,2% i 1,76 g/l&middot;h-1, ostvareni u drugoj fermentaciji. Upotrebom imobilisanih ćelija L. rhamnosus je osim povećanja prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline skraćena fermentacija za 12 sati u poređenju sa &scaron;aržnim fermentacijama.</p> / <p>Brewers spent grain represents (BSG) about 85% of the total by-products from brewing process and is available at low price during the whole year. Due to its chemical composition BSG has great potential use in biotechnology and production of high-value products. One of very eco-friendly and economical alternative uses of BSG is in production of lactic acid (LA), since in the last few decades the demand for the LA has significantly risen, mostly because of development of biodegradable lactic polymers, which are eco-friendly and nontoxic.<br />Lactic acid is the most important hydrocarboxylic acid with an asymmetrical carbon atom, widely distributed in nature, and it has shown great potential in fields of food, pharmaceutical, textile, leather and chemical industries.<br />The aim of this doctoral thesis was to investigate the application of BSG in lactic acid production. First, the optimization of enzymatic hydrolysis of BSG was conducted, with the goal to achieve high reducing sugar concentrations, as much as possible, that are necessary on LA fermentation. BSG hydrolysis was conducted by usage of commercial enzymes for degradation of starch and cellulose. Effect of pH value, temperature and enzyme dosage on BSG hydrolysis efficiency was investigated. After the best conditions for BSG hydrolysis were determined, the optimized procedure for BSG hydrolysis was used for the production of BSG hydrolysate that will be used in LA fermentations.<br />After optimization of BSG hydrolysis, LA fermentation by two LA producing microorganisms was investigated. The strains investigated were two LA bacteria strains: Lactobacillus fermentum PL-1 and Lactobacillus rhamnosus ATCC 7469. The effect of yeast extract (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%) addition in BSG hydrolysate, with the correction of pH value during LA fermentation by the addition of calcium-carbonate, on LA fermentation was investigated. Based on the results achieved for L-(+)- and D-(-)-LA ratio the LAB strains that produced more L-(+)-LA was chosen for further research.<br />In further research the effect of pH correction (with addition of NaOH), yeast extract (0.5, 1.0, 2.0, 3.0, 4.0, and 5.0%) addition and reducing sugar concentration (2.7; 5.4 and 8.1%) in BSG hydrolysate on LA fermentation was investigated. Based on the results achieved the best yeast extract and reducing sugars concentrations was determined and used in further analysis or research. Also the possible replacement of expensive yeast extract and glucose with cheap alternatives, like brewer`s spent grain and stillage was investigated. The effect of brewer`s spent grain (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%), whole stillage (5, 10, 15 i 20%) and thin stillage (5, 10, 15, 20, 30, 40, 50%) addition before fermentation as well as thin stillage addition in fed-batch fermentation in BSG hydrolysate on LA fermentation were investigated.<br />Also fed-batch fermentation procedure (addition of glucose, glucose and yeast extract and wort during fermentation) was investigated. The possible application of cells immobilized in Ca-alginate for LA fermentation of BSG hydrolysate was also investigated.<br />Based on the results it was concluded that BSG can be successfully utilized as a raw material in production of LA, after optimization of hydrolysis and addition of nitrogen source.<br />According to the results of chemical composition before and after optimized hydrolysis 78.6% of total cellulose was hydrolyzed.<br />Addition of calcium-carbonate had positive effect on LA production by L. fermentum i L. rhamnosus. With the addition of calcium-carbonate reducing sugar utilization, LA yield and concentration and cell viability (both L. fermentum i L. rhamnosus) increased. Addition of calcium-carbonate and yeast extract had a positive effect on LA fermentation by L. fermentum and L. rhamnosus. In LA fermentation by L. fermentum the highest LA yield (44%) was achieved with addition of 5.0% of yeast extract and 2.0% of calcium-carbonate. In L. rhamnosus fermentations the highest total LA yield (98%) and L-(+)-LA yield (96%) was reached when 2.0% of yeast extract and 2.0% of calcium-carbonate were added.<br />Based on the results achieved it was concluded that BSG hydrolysate, with the addition of yeast extract, is a good fermentation media for LA fermentation with L. rhamnosus, and it was decided that L. rhamnosus will be used in further research of LA fermentation on BSG hydrolysate.<br />Addition of NaOH instead of calcium-carbonate for the pH correction shortened the fermentation time by 48 h and increased the L-(+)-LA volumetric productivity (by 200%, from 0.21 to 0.63 g/L&middot;h-1). Based on this results pH correction in further experiments was done by addition of NaOH.<br />In LA fermentation with different reducing sugar (2.7, 5.4 and 8.1%) and yeast extract concentrations (0.5-5.0%), the highest L-(+)-LA yield and volumetric productivity of 91.29%, and 1.69 g/L&middot;h-1, respectively, as well as L. rhamnosus cell viability (9.67 log CFU/mL), were achieved with the reducing sugar content of 5.4% and yeast extract content of 5.0%.<br />Based on this results in further experiment with the addition of stillage, in fed-batch fermentation and fermentation with immobilized cell BSG hydrolysate with 5.4% of reducing sugars and 5.0% yeast extract was used.<br />In fermentation with the addition of brewer&rsquo;s spent yeast the highest L-(+)-LA yield (89.01%) and volumetric productivity (0.89 g/L&middot;h-1) were achieved in the fermentation of BSG hydrolysate with 5.0% of reducing sugar and 5.0% of brewer&rsquo;s yeast. Based on the results achieved it was concluded that yeast extract can be partial or complete replaced by brewer&rsquo;s spent yeast with significant decrease of media cost, without the decrease in LA fermentation efficiency.<br />In fermentation with the addition of thin stillage the highest L-(+)-LA concentration, yield, and volumetric productivity of 31.03 g/L, 86.15%, and 0.93 g/L&middot;h-1, respectively, was obtained in fermentation with the addition of 50% of thin stillage. The highest L-(+)-LA concentration, yield, and volumetric productivity achieved in fed-batch fermentation with the addition of glucose and thin stillage during fermentation, were 48,02 g/L, 87,82% i 0,96 g/L&middot;h-1.<br />In fed-batch fermentation the highest L-(+)-LA concentration, yield, and volumetric productivity of 116.08 g/L, 93.32%, and, 2.04 g/L h-1, respectively, were achieved in fermentation with glucose and yeast extract addition during fermentation. The results showerd that fed-batch fermentation could be used to increase L-(+)-LA fermentation efficiency<br />Immobilization of L. rhamnosus cells with high viability (1010 CFU/mL) in Ca-alginate was conducted. Immobilized cells we successfully utilized in three repeated batch fermentation. L-(+)-LA yield and volumetric productivity were very high in all three batch fermentation, with the highest results achieved (95.20% and 1.76 g/L&middot;h-1, respectively) in second fermentation. Application of immobilized L. rhamnosus cells increased L-(+)-LA yield and volumetric productivity and shortened the fermentation time for 12 h in comparison with batch fermentation.</p>

Physical and chemical properties of non-composted spent coffee (CF) and tea (T) suggest they may have applications as soil amendments for improving poor soils. Studies were conducted to determine 1) the effect of amendments on grass growth and soil properties, 2) the effect of incorporation versus surface application of amendments on soil properties, and 3) the effect of amendment application frequency on grass growth and soil properties. In the first study, amendments were mixed with sand and planted to bermudagrass. Treatments included CF, T, and peat moss (PM) mixed with sand, and 100% sand as a control. In the second study, amendments were topdressed onto a sand base with different timings. Pots were either aerified or not. Treatments included T, CF, PM, and a control. Nutrient contents and soil CEC and OM under CF and T treatments were equivalent to or greater than PM treatments. Tea showed comparable grass cover to the PM treatment, while CF showed an inhibitory effect to grass growth in the first year of the study. Aerification showed no benefit. Additionally, a field study was conducted to evaluate CF and T on surface hardness, VWC, and quality after trafficking. Differences were not observed among treatments.

Syftet med den här studien var att göra en kvantitativ datainsamling för att kartlägga om det fanns ett samband mellan användning av sociala medier, spel- och studietimmar och stress hos gymnasieungdomar i årskurs 3. Mätinstrumenten som användes var Social Media Addiction Scale (SMAS) och Perceived Stress Scale (PSS) samt två frågor om elevernas spel-och studietimmar.       Resultatet visade att det inte fanns några korrelationer som gav stöd för hypoteserna förutom när det gällde kvinnor, men eftersom de var underrepresenterade var det inte en stark sådan. Enligt resultaten för samband mellan stress, medieanvändning, studietimmar och speltimmar för kvinnor och män fanns det ett medelstarkt positivt samband mellan medieanvändning och studietimmar (r=.556), vilket innebar att ju större användning av sociala medier kvinnorna hade desto fler studietimmar hade de.       Lämplig framtida forskning skulle kunna vara kvantitativa longitudinella studier för att få en bredare analys. Som komplement skulle en kvalitativ intervjustudie kunna användas för djupare analyser inom området. / The aim of this study was to make a quantitative data collection to investigate the relationship between social media usage, time spent gaming, time spent studying and stress of upper secondary school students in grade 3. Two survey methods which were used in the study were Social Media Addiction Scale (SMAS) and Perceived Stress Scale (PSS) and two questions concerning time spent gaming and time spent on homework.       The result showed no significant correlations to support the hypotheses except for women but as they were underrepresented the correlation was insignificant. According to the results as for the relationship between social media usage, time spent gaming, time spent studying and stress of upper secondary school students for men and women a medium strong positive correlation (r=.556) between social media usage and time spent on homework was found in the study which implies that the more social media usage for women, the more time spent studying. Future research should consider quantitative longitudinal studies for broader analyses. Qualitative studies with interviews would help achieving a deeper analysis in the field.