• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 7
  • 7
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Storage and retrieval technique for K-value estimation

Joag, Ela Pramod 14 February 2011 (has links)
Many chemical processes need large computation time to simulate. It has been observed that the speed of a process simulation depends to a large extent on evaluation of certain important functions in the system to be simulated. One such function is K-value estimation function which involves heavy vapor-liquid equilibrium calculations. Because of large number of K-value calculations, there can be a bottleneck in simulation convergence. Thus within process simulation applications computational speed is often emphasized and accuracy is compromised. In situ adaptive tabulation or ISAT, a storage and retrieval technique is proposed for speeding up K-value estimation in a process simulator (CHEMCAD®) using the input-output data. C language code is developed to implement ISAT algorithm for this application. The C code is then converted into Dynamic link library to be able to be used vii by main CHEMCAD® code as required. The overall testing with different K-value databases gave promising results improving computational time while maintaining accuracy. / text
2

Modeling moisture absorption and thickness swelling for oriented strand board (OSB)

Slay, Robert Aaron 10 December 2010 (has links)
The dimensional stability of oriented strand board (OSB) can be affected by processing variables. This study investigated the water absorption and thickness swelling of OSB based on its board layup, type of resin, resin content, and percentage of wax. The experiment data was measured inside an environmental chamber from oven dry (OD) conditions to 80% relative humidity (RH), and from OD to 90% RH. The results suggest that single layer boards and isocyanate resin provide greater dimensional stability to OSB than three layer boards or phenol formaldehyde resin. In addition, the water absorption and thickness swell data were effectively modeled by equations developed for wood fiber/polymer composites.
3

Effects of support system on behavior and performance of continuously reinforced concrete pavement

Cho, Byoung Hooi 07 February 2011 (has links)
Support systems including base and subgrade layers play a pivotal role in manifesting and maintaining acceptable behavior and performance of continuously reinforced concrete pavement (CRCP). In Texas, especially, use of non-erodible stabilized base layers have been recommended to prevent failures of the CRCP related with pumping and erosion of the support materials. The non-erodible base materials, however, have given high initial construction cost of the rigid pavements. For this reason, it has been desired to decrease the construction cost with acceptable long-term performance of the pavement system. The primary objective of this study is to determine acceptable combination of support properties and concrete slab thickness satisfying not only adequate structural ability but also construction expense. For this purpose, field support conditions were investigated using Falling Weight Deflectometer (FWD), Dynamic Cone Penetrometer (DCP), and static plate load test in phase one. Previously developed support analysis models for rigid pavement design were examined using finite element analysis method, which model could more accurately express field support behavior. Also, effects of each support properties including base thickness, elastic modulus of base material, and subgrade k-value were mechanistically identified on composite k-value, and a method selecting optimum combinations of the support properties completing desired composite k-value was developed in phase two. Also, CRCP behavior were examined under not only diverse structural and material conditions of the support system but also the CRCP slab thickness and transverse crack spacing due to temperature and vehicle wheel loading conditions in phase three. In phase four, maximum critical stress induced in the CRCP slab was evaluated under various combinations of support conditions and slab thickness. Effects of the support properties and the slab thickness on the critical stress in the CRCP slab were mechanistically identified, and the factor with the greatest effect was verified. Moreover, regression equations were developed to estimate the maximum critical stresses for various support properties and the CRCP slab thickness under temperature and wheel loadings. In phase five, a guideline determining optimum combination of support properties and slab thickness were proposed as aspect of initial construction cost of the CRCP. / text
4

PREDICTION OF FISH FRESHNESS USING UV-VISIBLE SPECTROSCOPY OF EYE FLUID / 眼液の紫外・可視分光を用いた魚の鮮度予測

Anisur, Rahman 24 November 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19378号 / 農博第2148号 / 新制||農||1037(附属図書館) / 学位論文||H28||N4958(農学部図書室) / 32392 / 新制||農||1037 / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 近藤 直, 教授 飯田 訓久, 准教授 小川 雄一 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
5

VÄRMEGENOMGÅNGSTALETS UTVECKLING : Progress of the heat transfer coefficient

Kruszewski, Tomasz, Olsson, Anna January 2023 (has links)
År 1947 var k-värde, värmegenomgångstal, aktuellt och Sverige var indelat i olika zoner med lokala byggregler. Sedan dess har bygglagstiftningens utveckling gått framåt. Lagen har förändrats och många nya föreskrifter och anvisningar har utgivits under årens gång. Det förekommer inte längre några zoner eller lokala byggregler. I dag är begreppenvärmegenomgångskoefficient (Um) och byggnadens primärenergital (EPpet) aktuella.Denna rapport innehåller en sammanställning över tillåtna värden för värmegenomgångstalet och hur det utvecklats från 1947 fram till i dag. Rapportens syfte är att skapa en förenklad sammanställning över hur värmegenomgångstalet förändrats historiskt med hänsyn till bygglagstiftning. En översikt för antalet småhus och flerbostadshus är också inkluderad. Sammanställningar över dessa värden fyller en viktig funktion i förarbetet till Fit for 55 och är betydelsefullt för övriga kommande miljöarbeten. Litteraturstudien har utgått från regelverken BABS, SBN, NR, och BBR. Statistiken för antalet bostäder är hämtad från SCB.Arbetet omfattar byggregler från BABS 46 fram till BBR 29 och inkluderar endast byggnadsdelarna golv, vägg och tak. Sammanställning för värmegenomgångstalets utveckling är begränsad till bostad. Resultatet redovisas i tabeller och diagram. Sammanställningen gav en tydligare bild av hur värmegenomgångstalet har förändrats och var förändringen var som störst.  Syftet var att sammanställa en förenklad version av värmegenomgångstalets (k-värdets) utveckling genom historien, vilket är uppnått. / By 1947, k-value, was the standard value and Sweden was divided into different zones with local building regulations. Since then, the progress of the building legislation has been moving forward. The law has changed, and many new regulations and instructions have been published during the years. There are no longer any zones or local regulations. Today, the current concepts are U-value and EPpet. This report includes a compilation of allowed values for k-value and how it has been developing since 1947 until today. The purpose of the report is to create a simplified compilation of how k-value has been developing historically regarding building legislation. An overview of the numbers of small houses and apartment buildings are also included. Compilations of this type of values are an important part in the preparatory work to Fit for 55 and are also valuable for upcoming environmental work. The literature study has been done from the regulations BABS, SBN, NR and BBR. The statistics of the numbers of homes has been collected from the SCB. The work covers building regulations from BABS 46 until BBR 29 and only includes the building parts floor, wall, and roof. The compilation of the development of k-value is limited to residences.The outcome/result is reported in charts and graphs. The compilation gave a clearer picture of how k-value has developed and where the biggest changes occurred. The purpose was to compile a simplified version of the k-values development throughout history, a purpose which was achieved.
6

Technologies for tissue preservation: the role of endogenous and exogenous antioxidants in preserving tissue function in chinook salmon, Oncorhynchus tshawytscha

Tuckey, Nicholas Pierre Lemieux January 2008 (has links)
The seafood industry is of considerable importance to both the New Zealand and global economies and therefore tissue preservation technologies that increase product quality and/or prolong shelf life have the potential to add significant value. Technologies for maintaining the viability of isolated tissues also have a wide range of other medical and industrial applications. This thesis examines the relationship between metabolic function, oxidation and cell death and the resulting stability of the non-viable tissues during long term storage in chinook salmon (Oncorhynchus tshawytscha) red and white skeletal muscle tissue. This research also looks at the role of the aquatic anaesthetic AQUI-S™, in which the active ingredient is isoeugenol (a lipid soluble antioxidant), and other antioxidant compounds in preserving metabolic function in viable tissues and tissue stability in nonviable tissues. Perfusion of salmon tails at 15℃ over 5 or 10 hours with oxygen saturated saline resulted in significant increases in protein and lipid oxidation (protein carbonyl and TBARS concentrations respectively) in the red muscle, but not the white muscle. The introduction of ascorbic acid and uric acid into the saline did not reduce the oxidation in the red muscle despite significantly increasing their respective concentrations in the tissue. This indicates the difficulties associated with attempting to extend tissue viability by delivering free oxygen to the tissue and also highlights the difference in susceptibility of the two muscle types to oxidation. Tail fillets from salmon harvested in both rested and exhausted physiological states using AQUI-S™, and fillets from exhausted salmon harvested without AQUI-S™, were exposed to air at 15℃ for up to 96 hours. Protein carbonyls increased in a roughly linear fashion over the entire 96 hours in all three groups. Both lipid peroxides (TBARS) and uric acid concentrations began to increase in the exhausted group after 30 hours. In contrast, no significant increases in lipid peroxides or uric acid was seen in the fillets from either group harvested using AQUI-S™. Vitamin E concentrations reduced slowly but did not change significantly despite the oxidation that was evident in the tissue. These processes also occurred in salmon tail fillets during storage at 6℃. The measurement of ATP related compounds provides an effective indicator of both the metabolic state of the tissue post-harvest and the quality. The breakdown of these compounds is also associated with the production of ammonia and hydrogen peroxide. Fresh rested salmon fillets had high concentrations of ATP and creatine phosphate, which were both depleted after 12 hours storage at 15℃. This indicates that cell viability lasted a number of hours following harvesting. These metabolites were depleted in exhausted fillets and metabolic potential appeared to be immediately compromised. The concentration of the taste enhancing compound IMP was significantly reduced in fresh rested tissue, but increased during storage, and was significantly higher than in exhausted tissues following 12 hours of storage at 15℃. This indicates that some properties of rested tissues may improve with limited storage times. The accumulation of uric acid - the metabolic end point for ATP related compounds - was also significantly reduced in rested tissue and increases in K-value were slowed. AQUI-S™ showed an ability to preserve tissue function through its anaesthetic action allowing tissue to be harvested in a rested state, and to reduce late stage lipid oxidation in stored salmon tail fillets. The antioxidant action of isoeugenol in salmon fillets may be mediated through its ability to chelate transition metals released during tissue degradation. This research shows that during reperfusion and during fillet storage there is a significant level of oxidative stress, which needs to be minimized while maintaining basic tissue metabolism to prolong tissue and cellular viability. The development of future technologies to preserve tissue viability may depend on the development of a synthetic oxygen carrying compound with properties similar to red blood cells. This may allow more control over oxygen delivery, potentially reducing the oxidative stress associated with high concentrations of free oxygen in solution. However, preserving cell viability will also require the maintenance of endogenous antioxidant function and there is also the potential to use iron chelating compounds including plant derived flavonoids to preserve non-viable tissues. Future research in these areas is necessary.
7

Technologies for tissue preservation: the role of endogenous and exogenous antioxidants in preserving tissue function in chinook salmon, Oncorhynchus tshawytscha

Tuckey, Nicholas Pierre Lemieux January 2008 (has links)
The seafood industry is of considerable importance to both the New Zealand and global economies and therefore tissue preservation technologies that increase product quality and/or prolong shelf life have the potential to add significant value. Technologies for maintaining the viability of isolated tissues also have a wide range of other medical and industrial applications. This thesis examines the relationship between metabolic function, oxidation and cell death and the resulting stability of the non-viable tissues during long term storage in chinook salmon (Oncorhynchus tshawytscha) red and white skeletal muscle tissue. This research also looks at the role of the aquatic anaesthetic AQUI-S™, in which the active ingredient is isoeugenol (a lipid soluble antioxidant), and other antioxidant compounds in preserving metabolic function in viable tissues and tissue stability in nonviable tissues. Perfusion of salmon tails at 15℃ over 5 or 10 hours with oxygen saturated saline resulted in significant increases in protein and lipid oxidation (protein carbonyl and TBARS concentrations respectively) in the red muscle, but not the white muscle. The introduction of ascorbic acid and uric acid into the saline did not reduce the oxidation in the red muscle despite significantly increasing their respective concentrations in the tissue. This indicates the difficulties associated with attempting to extend tissue viability by delivering free oxygen to the tissue and also highlights the difference in susceptibility of the two muscle types to oxidation. Tail fillets from salmon harvested in both rested and exhausted physiological states using AQUI-S™, and fillets from exhausted salmon harvested without AQUI-S™, were exposed to air at 15℃ for up to 96 hours. Protein carbonyls increased in a roughly linear fashion over the entire 96 hours in all three groups. Both lipid peroxides (TBARS) and uric acid concentrations began to increase in the exhausted group after 30 hours. In contrast, no significant increases in lipid peroxides or uric acid was seen in the fillets from either group harvested using AQUI-S™. Vitamin E concentrations reduced slowly but did not change significantly despite the oxidation that was evident in the tissue. These processes also occurred in salmon tail fillets during storage at 6℃. The measurement of ATP related compounds provides an effective indicator of both the metabolic state of the tissue post-harvest and the quality. The breakdown of these compounds is also associated with the production of ammonia and hydrogen peroxide. Fresh rested salmon fillets had high concentrations of ATP and creatine phosphate, which were both depleted after 12 hours storage at 15℃. This indicates that cell viability lasted a number of hours following harvesting. These metabolites were depleted in exhausted fillets and metabolic potential appeared to be immediately compromised. The concentration of the taste enhancing compound IMP was significantly reduced in fresh rested tissue, but increased during storage, and was significantly higher than in exhausted tissues following 12 hours of storage at 15℃. This indicates that some properties of rested tissues may improve with limited storage times. The accumulation of uric acid - the metabolic end point for ATP related compounds - was also significantly reduced in rested tissue and increases in K-value were slowed. AQUI-S™ showed an ability to preserve tissue function through its anaesthetic action allowing tissue to be harvested in a rested state, and to reduce late stage lipid oxidation in stored salmon tail fillets. The antioxidant action of isoeugenol in salmon fillets may be mediated through its ability to chelate transition metals released during tissue degradation. This research shows that during reperfusion and during fillet storage there is a significant level of oxidative stress, which needs to be minimized while maintaining basic tissue metabolism to prolong tissue and cellular viability. The development of future technologies to preserve tissue viability may depend on the development of a synthetic oxygen carrying compound with properties similar to red blood cells. This may allow more control over oxygen delivery, potentially reducing the oxidative stress associated with high concentrations of free oxygen in solution. However, preserving cell viability will also require the maintenance of endogenous antioxidant function and there is also the potential to use iron chelating compounds including plant derived flavonoids to preserve non-viable tissues. Future research in these areas is necessary.

Page generated in 0.0321 seconds