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  • 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.
591

Thermal cis-to-trans isomerization mechanism of N-(phenylazo)-substituted nitrogen heterocycles

Fu, Jinlong January 2008 (has links)
Triazenes, compounds containing a diazoamino moiety (–N(1)=N(2)–N(3)<), are known for their reversible cis-trans isomerization character and hence, have the potential to be used in photoswitchable devices and photostorage media. However, little is known about their cis-trans isomerization mechanism. In this thesis, kinetic studies on the thermal cis-to-trans isomerization of N-(phenylazo)-substituted nitrogen heterocycles are presented. It is shown that the isomerization rate constant increases as the size and electron-donating character of the cyclic amine increases, as the electron-withdrawing character of the para substituent group on the phenyl ring increases, and as the polarity of the solvent increases. All these trends are interpreted in terms of a rotational isomerization mechanism involving a dipolar transition state. In addition, photolytic cleavage of the N(2)–N(3) bond of target substrates is shown to be affected as well by the size and electronic character of the cyclic amine, the electronic character of the phenyl ring substituent, and the polarity of the solvent, with the result that the photolysis yield increases as the isomerization rate decreases. Theoretical calculations on target substrates both in the gas phase and various solvents were also performed based on DFT-B3LYP/6-31+G* method. Overall, the cis-to-trans isomerization is predicted to take place through rotation around the N(1)=N(2) bond. Furthermore, the calculated energy barriers are found to be influenced by the size and electronic character of the cyclic amine, the electronic character of the phenyl ring substituent, and the polarity of the solvent, consistent with the effects obtained experimentally from the kinetic studies.
592

Firm Size and Characteristics of Innovations in the Markets for Technology

Leung, Jeffery Pui Hin January 2009 (has links)
This paper investigates how the size of a firm affects its licensing strategy for patented technologies through empirical analysis of the characteristics at the technological, firm, and industry levels. Only firms with commercialization capabilities are considered in this study in order to compare the incentives of utilizing technologies internally with the incentives of selling them for licensing revenue. Focusing on licensing motivated by non-strategic purposes, empirical analysis shows that large companies are less willing to license patents that fit into their business focus, as well as those which have a low technological value in general. On the other hand, small firms are more inclined to license patents which are more relevant to their business focus, but less innovative on average. This study also finds that market share and competition intensity are important factors in their licensing decisions: the more competitive and the smaller the market share of the patents owned by large firms, the higher the chance that firms will list them on the market. In line with the revenue versus competition framework by Arora and Fosfuri (2003), this paper concludes that large firms are generally more concerned about the rent dissipation effect over the revenue effect from licensing, while the opposite is true for smaller firms.
593

Correlation between physical properties and flowability Indicators for fine powders

Bodhmage, Abhaykumar Krishnarao 03 July 2006 (has links)
Approximately 80% of pharmaceutical products and the ingredients required for their manufacture are in powder form. The solid dosage form (tablets and capsules) is manufactured by either dry-blending of fine powder ingredients or combining the ingredients in a wet granulation step, followed by drying. Arching, ratholing, caking, segregation and flooding are some of the commonly encountered flow problems in the handling of fine powders. These problems lead to losses worth thousands of dollars at production scale. Poor powder flowability is a consequence of the combined effects of many variables, including improper equipment design, particle size, size distribution, shape, moisture content and surface texture. In the present work, a systematic study has been performed to determine the relationship between the flowability of fine powders and their physical properties of mean size and size distribution, density and shape.<p> Flowability studies were done on six different powders: the NutraSweet® Brand sweetener (aspartame), Respitose ML001, Alpha-D-Lactose monohydrate, the pharmaceutical binder Methocel (R) F50 Premium Hydroxypropyl methylcellulose- HPMC, a placebo pharmaceutical granulate, and common pastry flour. Scanning electron microscopy (SEM) and stereomicroscopy were used for particle shape and size analysis. Particle size distribution was determined using the laser light scattering technique. Powder flowability was measured using shear strength, angle of repose, and tapped-to-bulk density measurements. A novel method of measuring the dynamic angle of repose using electrical capacitance tomography (ECT) was developed. <p> Analysis of the images from microscopy revealed that the particles of aspartame and HPMC powders were elongated, the particles of ML001, pastry flour and lactose monohydrate powders were irregular, and the particles of placebo granulate were nearly spherical. Particle size was found to be the most reliable indicator of powder flowability, with decreasing particle size corresponding to lower flowability; however other parameters such as particle elongation and irregularity, were also found to have an influence on powder flowability. Although HPMC and pastry flour had similar particle sizes, they exhibited differences in flowability. This can be explained by the greater irregularity of the flour particles. Particle irregularity may cause mechanical interlocking between the particles, thus reducing powder flowability. ECT was found to be a promising non-intrusive tool for the measurement of the dynamic angle of repose. Unlike other methods for the measurement of dynamic angle of repose, the results obtained from ECT were not influenced by the effect of end caps. The present technique could be used by pharmaceutical industries in process analytical technology (PAT) for the detection and elimination of potential flow problems early in the manufacturing process.
594

The effects of housing grow-finish pigs in two different group sizes and floor space allocations

Street, Brandy Rose 24 November 2005 (has links)
Crowding of grow-finish pigs reduces growth and is considered a welfare issue. Most crowding studies have been limited to smaller group sizes than are currently being considered in the swine industry. It has been hypothesized that pigs in large groups require less space to maintain growth and welfare. The objective of this study was to examine the effects of group size and space allowance on the performance, health and welfare of grow-finish pigs. The study consisted of eight blocks, each with four experimental units in a 2 x 2 factorial arrangement of group size (18 vs. 108 pigs/pen) and space allowance (0.52 vs. 0.78 m2/pig). Health assessments were conducted daily; production data were collected weekly; injury scores, behaviour and salivary cortisol data were collected bi-weekly; and carcass and adrenal gland data were collected at slaughter. Gains were lower for crowded pigs, but the effects were limited to the final week of the study. Pigs in crowded groups had a lower feed efficiency, which followed a trend similar to that of gains over time. In the crowded groups, pigs spent less time at the feeder, but no other variables differed among space allowances. Gains were lower for pigs housed in large groups, but the effects were limited to the initial two weeks of the study. Pigs in large groups had a lower feed efficiency and more lameness and leg sores. Other health measures did not differ between the group sizes. Lying behaviour of pigs in large groups indicated that they were able to utilize free space more efficiently than pigs housed in small groups. Analysis of feeding patterns suggests that pigs housed in large crowded groups were able to manoeuvre around their environment more easily than those in small crowded groups, yet performance of pigs in large groups was similarly affected by space restriction as pigs in small groups. Interactions of group size and space allowance indicated that pigs in large crowded groups were more susceptible to lameness. There was no indication that pigs in large groups required less space, or could perform as well at reduced space allowances, than pigs in small groups.
595

Grain hardness and slow dry matter disappearance rate in barley

Camm, Giselle Anne 07 April 2008 (has links)
Barley grain is an important source of energy and protein for ruminant animals. However, feeding must be carefully managed to avoid maladies caused by the rapid breakdown of barley starch in the rumen. The development of slower degrading barley for ruminants may alleviate health problems associated with barley grain consumption. Selection for hard endosperm may result in slower starch degradation and improved feed quality. The objectives of this study were to: examine the effect of grain hardness, variety and environment on dry matter disappearance rate (DMDR); identify accurate and efficient hardness selection tools; and study environmental effects, inheritance and heritability of hardness.<p>To study grain hardness and genetic and environmental effects on DMDR, two genotypes grown at multiple locations in 2004 were analyzed for Single Kernel Characterization System (SKCS) hardness, by scanning electron microscopy (SEM), and for in situ DMDR. Genotype by environment interaction influenced DMDR, while neither SKCS hardness nor SEM analysis accurately differentiated DMDR between genotypes. <p>Eight genotypes were grown at multiple locations during 2003 and 2004 to study grain hardness measurement methodology, and genetic and environmental effects on hardness. Genotypes were analyzed for SKCS hardness, milling energy, endosperm light reflectance, feed particle size, protein and beta-glucan. Hardness measurements ranked genotypes similarly across environments. Feed particle size was correlated with milling energy but not other hardness measurements. Hardness measurements appeared to be influenced by protein and beta-glucan.<p>To examine the inheritance and heritability of barley grain hardness, 245 double haploid (DH) genotypes and parents, grown in 2003 and 2004, were analyzed for SKCS hardness, milling energy, protein, beta-glucan, with 100 evaluated for light reflectance. The population exhibited normal distributions for SKCS hardness, milling energy, protein and beta-glucan, suggesting quantitative inheritance for these traits with no apparent epistatic gene interaction. Narrow-sense heritability was 0.75 for SKCS hardness and 0.41 for protein. Light reflectance was not normally distributed, suggesting complementary gene interaction. Broad-sense heritability was 0.53.<p>Barley grain hardness is highly heritable and an efficient tool in making selections in a breeding program. However, breeding for high beta-glucan and protein may be better selection criteria for indirect selection of DMDR.
596

Hull, ferulic acid, para-coumaric acid content and particle size characteristics of various barley varieties in relation to nutrient availability in ruminants

Du, Liqin 12 January 2009 (has links)
The fibrous barley hull is the main reason for barleys low available energy relative to corn. Barley grain contains hydroxycinnamic acids (mainly ferulic acid (FA) and ñ-coumaric acid (PCA)) which are cross-linked to polysaccharides, therefore, limit cell wall degradability in the rumen. Paricle size of barley grain also affects the digestion of barley in the rumen. The objective of this study was to evaluate a set of barley varieties grown in Saskatchewan (Canada) and provided by Crop Development Center (CDC, Canada) and find a variety with low hull, FA, PCA and fiber content, while maintaining large particle size after mechanical processing, and having high nutrient availability.<p> Three studies were conducted to determine the content of barley hull, FA, PCA, neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) in various barley varities. Mean/median particle size of the barley grain after coarse dry-rolling was also determined. The relationships among these parameters and the digestibility of barley grain in ruminants were then assessed. Six barley varieties (AC Metcalfe, CDC Dolly, McLeod, CDC Helgason, CDC Trey and CDC Cowboy) from samples grown in three years (2003, 2004 and 2005) were evaluated in each study.<p> The first study determined the original content of barley hull, FA, PCA, NDF, ADF, ADL, and mean/median particle size of barley grain and evaluated the effects of barley variety. The results showed barley variety had a significant impact on the chemical and physical profiles of barley grain, with CDC Helgason and CDC Dolly showing relatively lower content of barley hull, FA, PCA, NDF, ADF, ADL, hemicellulose and cellulose, and moderate mean/median particle size, whereas McLeod and CDC Cowboy showed the opposite.<p> The second study involved two consecutive trials. Trial 1 was to assess differences in the in situ rumen degradability of dry matter (DM), FA, PCA, NDF, ADF and ADL at 12 and 24 h of rumen incubations. Results revealed that CDC Dolly consistently showed relatively lower rumen residues of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h, with McLeod being opposite. Barley variety displayed some effects on the digestibility of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h. Since CDC Dolly demonstrated relatively less content of hull, FA, PCA, NDF, ADF, ADL and mean/median particle size and higher rumen digestibility among the six barley varieties, while McLeod was the opposite, CDC Dolly and McLeod were selected for the third trial in order to compare differences in the rumen degradation kinetics of DM, FA and PCA. Trial 2 did not show significant differences in effective degradation of DM, FA, except for PCA. In general, CDC Dolly exhibited better degradability of DM, FA and PCA than McLeod.<p> The third study analyzed the correlation and regression between the original content of barley hull, FA, PCA, NDF, ADF, ADL and mean/median particle size in barley grain and rumen residual content of the corresponding parameters at 12 and 24 h of rumen incubation. Results showed that FA content in barley grain had a predominantly negative effect on DM degradability, while barley hull content affected the degradability of NDF and ADF.<p> In summary, the present studies show that hull and FA content in barley grain have negative effects on the degradability of barley grain in ruminants and also showed that CDC Dolly could be an ideal feed barley grain for ruminants due to its lower hull and FA content and higher rumen dry matter degradability.
597

ACQUIRING “BIG” KNOWLEDGE : RAISING AWARENESS OF PITFALLS

Ivarsson, Linus, Johansson, Rickard January 2012 (has links)
This report highlights the complexity of engaging in a post-acquisition integration process of a relatively large knowledge-intensive firm. Findings from a case study is analyzed in relation to previous theory, resulting in four propositions aiming at creating a foundation for further theory development, as well as increased understanding among practitioners in relation to the emphasized problem. It is argued by the authors that increased relative acquisition size of knowledge-intensive firms will: 1) increase demand for a centralized organizational structure, 2) decrease benefits of introducing a new top management, 3) decrease communicative attention towards lower levels, and 4) decrease attention towards subcultures. These factors will ultimately increase the risk for integration failure.
598

The impact of e-commerce on small-size companies in Sweden

Ivanov, Diyan January 2012 (has links)
The purpose of this thesis is to examine the influence of e-commerce on the small-size companies in Sweden. This thesis describes the drivers for e-commerce adoption and investigates the barriers and benefits faced from the companies when starting the process of implementation. A qualitative research was performed and an abductive approach was used, where the research findings and the theoretical background were connected by going back and forward in the process of analysis. Interviews with small companies in Värmland Country, Sweden were conducted in order to answer the research questions. This study shows that Swedish companies have relatively well-developed e-commerce strategies comparing to other counties, but the gap between small and large companies is still visible. The decisions for e-commerce adoption are dependent on the knowledge of the owner /manager and e-commerce is extensively used as a marketing tool. Main benefits of e-commerce adoption are improved internal efficiency and increased information exchange. The results suggest that companies value less than before the cost factor and consider the lack of knowledge as a main barrier. At the same time many companies are not motivated enough to make improvements, because of lack of customer demand.
599

Location and rank-size distribution of Arts and Entertainment : A study of US Metropolitan Regions

Ruett, Benjamin January 2010 (has links)
This thesis describes and analyzes the location and size distribution of artand entertainment establishments and metropolitan regions in the UnitedStates. The included sectors are sound recording, motion picture and video,book and newspaper publishing as well as the live performing arts. Their sizeis analyzed by total employment and brought in context to their respectivemarkets and the rank-size rule. The results are interpreted within the economictraits specific to the art and entertainment industry.The results show that most analyzed sectors are over proportionally concentratedin one location, making it the center for these activities. In addition, thesize distribution in all sectors except sound recording follows Zipfs law to agreat extend. Explanations for this can be found in lock-in mechanisms overtime and classic agglomeration advantages.
600

XS architecture versus XL furniture : the scale in-between

Manupipatpong, Worapong January 2009 (has links)
The manipulation of space, materials and issues about shape, color, texture and gravity are common to architecture and furniture. For my degree project, I examine the three-dimensional territories of architecture and furniture. I investigate how the notion of architecture can influence furniture design, or the other way around. Many times, architects cross the boundary from building to furniture design to try and challenge themselves with different scale as same as designer. With my project, I don’t want to cross the border between them, but rather seek the space in-between the two territories, where design and architecture are blended. I’m intrigued by particular spaces and things when they can’t be classified exactly; something in-between. It leaves me with curiosity, inspiration and space for imagination. My project can be seen as something in-between because it is hard to define. Whether it is extra small architecture or an extra large piece of furniture, it is somewhere in-between these aspects of scale and function. / Master / InSpace 2009

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