In situ measurements of building materials using a thermal probe

Access to the full version of this thesis is unavailable due to third party copyright restrictionsMerged with duplicate record 10026.1/2243 on 13.03.2017 by CS (TIS)This work concerns the in situ measurement of thermal conductivity and thermal diffusivity of building materials, so as to provide improved data for the estimation and prediction of energy efficiency in buildings. Thermal data sources and measurement methods currently used by industry to inform building design were found to give flawed values for the thermal properties of materials as found in situ. A transient measurement technique, carried out by means of a thermal probe, and used in various other industries, was investigated as an alternative, relatively non-destructive, rapid and economic means of obtaining representative results. An analysis of the literature associated with the technique's history, theory and practice was carried out. Four strands of scientific research were undertaken: traditional thermal probe solutions were assessed; computer simulations were used to model probe behaviour while avoiding practical, experimental error; laboratory based measurements were carried out with materials of known and unknown thermal properties using varied parameters, including moisture content; an apparatus was developed for fieldwork, and in situ measurements were carried out on real buildings, using novel analysis routines. Results for thermal diffusivity values achieved by the thermal probe method were found to be unreliable. Representative thermal conductivity values were achieved for structural materials with varied moisture content, both in controlled laboratory environments and in situ under diverse environmental conditions, which had not previously been achieved. Heat losses from the probe open end and the material adjacent to it were shown to currently prevent reliable values being obtained for building insulation materials. The thermal probe technique was successfully transferred from laboratory to in situ measurements. It was shown that various calibration factors reported in the literature could not be relied upon to transfer successfully between material types. A significant cause of error in the measurement of insulation materials was identified and a guarded probe was proposed to overcome this. The technique was shown to provide much improved thermal conductivity data for structural building materials, whether as samples or in situ, with the potential to expand this success to insulation materials in the future

Horticultural Crop Response to Different Environmental and Nutritional Stress

Environmental conditions and nutritional stress may greatly affect crop performance. Abiotic stresses such as temperature (cold, heat), water (drought, flooding), irradiance, salinity, nutrients, and heavy metals can strongly affect plant growth dynamics and the yield and quality of horticultural products. Such effects have become of greater importance during the course of global climate change. Different strategies and techniques can be used to detect, investigate, and mitigate the effects of environmental and nutritional stress. Horticultural crop management is moving towards digitized, precision management through wireless remote-control solutions, but data analysis, although a traditional approach, remains the basis of stress detection and crop management. This Special Issue summarizes the recent progress in agronomic management strategies to detect and reduce environmental and nutritional stress effects on the yield and quality of horticultural crops

Research in Biological Control of the Formosan Subterranean Termite

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a worldwide distributed pest of wooden structures and living plants that causes huge economic losses. Compared to chemical pesticides, biological control may provide a more environmentally friendly and persistent method for the control of C. formosanus. In this research, a series of studies were conducted to understand the termite-pathogen interaction and to develop a feasible biological control strategy. In the first part of the research, the toxicity of Bt toxins expressed by genetically modified maize to termites was tested. Plant tissues or extracts of three commercially planted Bt maize and two non-Bt maize were provided to termites as food. The results revealed no significant difference in survival rate, food consumption or length of tunnels among termites feeding on Bt and non-Bt maize. The following experiments show that maize cob can be used as a termite bait matrix. In the second part of the research, the susceptibility of C. formosanus to MosquitoDunks®, which contains about 10% of the entomopathogenic bacterium, Bacillus thuringiensis subspecies israelensis, was tested. No-choice and choice bioassays did not show a promising lethal effect of MosquitoDunks® on termites. Furthermore it was shown that C. formosanus can suppress the growth of B. thuringiensis. Also, clay was tested for its potential to be a termite bait matrix that can be used to encapsulate biological control agents. Choice tests showed that significantly more termites aggregated in chambers where clay was provided, indicating the possibility of clay to be used as a termite attractant. In the third part of the research, the potential to combine a biological control agent and a chemical pesticide against termites was investigated. The effect of low concentrations of lufenuron, a chitin synthesis inhibitor, on termite physiology and behavior was tested. Results showed that lufenuron significantly reduced vigor and disease resistance of termites. In the following experiments, termite mortality was significantly higher and synergistic in the combination of lufenuron and Pseudomonas aeruginosa (Schroeter) compared to treatment of lufenuron or P. aeruginosa alone. To combine lufenuron and a termite pathogen may bring a successful IPM strategy for the control of termites

Security and Privacy in Mobile Computing: Challenges and Solutions

abstract: Mobile devices are penetrating everyday life. According to a recent Cisco report [10], the number of mobile connected devices such as smartphones, tablets, laptops, eReaders, and Machine-to-Machine (M2M) modules will hit 11.6 billion by 2021, exceeding the world's projected population at that time (7.8 billion). The rapid development of mobile devices has brought a number of emerging security and privacy issues in mobile computing. This dissertation aims to address a number of challenging security and privacy issues in mobile computing. This dissertation makes fivefold contributions. The first and second parts study the security and privacy issues in Device-to-Device communications. Specifically, the first part develops a novel scheme to enable a new way of trust relationship called spatiotemporal matching in a privacy-preserving and efficient fashion. To enhance the secure communication among mobile users, the second part proposes a game-theoretical framework to stimulate the cooperative shared secret key generation among mobile users. The third and fourth parts investigate the security and privacy issues in mobile crowdsourcing. In particular, the third part presents a secure and privacy-preserving mobile crowdsourcing system which strikes a good balance among object security, user privacy, and system efficiency. The fourth part demonstrates a differentially private distributed stream monitoring system via mobile crowdsourcing. Finally, the fifth part proposes VISIBLE, a novel video-assisted keystroke inference framework that allows an attacker to infer a tablet user's typed inputs on the touchscreen by recording and analyzing the video of the tablet backside during the user's input process. Besides, some potential countermeasures to this attack are also discussed. This dissertation sheds the light on the state-of-the-art security and privacy issues in mobile computing.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Evaluation and prediction of corn stover biomass and composition from commercially available corn hybrids

ABSTRACT High consumption of imported energy in the United States and other countries has increased the interest in bio-renewable sources of energy. This interest has fueled research into crop residues as one potential alternative fuel source. At issue is how to balance economic viability with the sustainability of the endeavor. The objective of this project was two-fold. The first objective was to quantify the amount and distribution of dry matter, moisture, fiber, and minerals in corn stover from a number of corn hybrids, grown at varying population densities. In this multi-year study we found that of the stover material remaining after harvest roughly 55% is found in the stalk and leaf material below the ear, 25% in the stalk and leaf material above the ear and the remaining 20% is found in the cob (12%) and husk (8%). The moisture, composition, and mineral concentration were significantly affected by year, planting density, and hybrid. Due to the highly variable quantities of biomass and the composition and nutrient concentrations within the stover fractions our guidance is to collect and analyze representative samples from each field level treatment in order to accurately predict stover constituents. The second objective was to develop a predictive model which can be used to quantify corn stover biomass present on a given field. Harvest index (HI) values were calculated in order to evaluate their value in predicting stover biomass. However the significant variability observed in the two years tested limited the usefulness of this ratio in predicting stover biomass. Given the variation in HI, its utility as a stable, predictive measurement across years and productivity levels for the estimation of stover biomass is questionable. In the evaluation of HI in highly productive environments commercially available corn hybrids averaged 0.55 kg kg-1and can achieve HI levels of 0.60 kg kg-1. However, under stressful conditions these levels are significantly lower. Plant density is a significant variable for HI in stressful conditions. Additional morphological measurements were collected for the development of an allometric model. A trend was observed for the fractions evaluated and a composite model fit the corresponding measured biomass with an adjusted R2 of 0.55. However, when the model was applied to the validation data set, very poor predictions were observed for each fraction and in composite. The data gathered from this research, which was gathered and utilized to develop predictive models for the estimation of corn stover biomass, characterized a large amount of variation which exists across current corn production variables. To characterize this variation properly the data suggest adequate sampling across all field level variables is necessary to accurately predict corn stover biomass. If estimates must be made it is suggested to use conservative estimates of stover biomass, for example a HI ratio of 0.55 : 0.45 kg kg-1 of grain to stover. It is hoped that with this conservative estimate and other field level considerations such as slope and soil type that adequate residue remains on the soil to protect and build our natural resources in a sustainable manner

Genetic and Environmental Effects on Kernel Number and Ear Length in Corn (Zea Mays L.)

A 6-entry diallel set involving 3 temperate and 3 tropical corn inbreds was planted monthly in Hawaii during a 21-month period from August, 1977 to May, 1979 to study the effects of seasonal change in climatic factors on kernel number and ear length and the stability of these characters. Another 10-entry diallel set involving 5 temperate and 5 tropical corn inbreds was evaluated at different locations in temperate and tropical regions to study the effects of geographically diverse environments on kernel number and ear length and their relationships to grain yield. Also, generation mean analysis based on 6 crosses among 2 temperate and 2 tropical corn inbreds was carried out to study the genetics of kernel number and ear length. Under seasonal environments where cyclic changes in climatic conditions influence corn growth, the days to maturity of the corn plants were mainly determined by temperature and the vegetative growth of the corn plants was a function of the solar radiation available to the corn plants before silking. Corn plants were more sensitive to slight climatic changes during winter months than during summer months. Fifteen corn hybrids among 6 inbred lines did not differ significantly for almost all ear characters when seasonal environments were favorable for corn growth, but showed significant differences under unfavorable conditions. General combining ability (GCA) and specific combining ability (SCA) mean squares and GCA x month interaction mean squares were significant indicating that both additive and nonadditive genes contributed to the genetic variation in ear characters with a significant contribution by the additive x month interaction. Kernels per row, kernels per ear, cob length, filled ear length and grain yield followed the cyclical change in solar radiation, while floret number and row number were quite stable in seasonal environments. Average daily solar radiation during the 3rd month of the corn plant's growth explained 65 % of the variation in kernel number, ear length and grain yield. A non-linear asymptotic regression line showed that the expression of ear characters and grain yield was greatly influenced by a small change in solar radiation under unfavorable environments. Lower temperature during the winter season extended the growing period of the corn plants and compensated for the low irradiance, thus maintaining a grain yield higher than predictions based on solar radiation levels alone. The stable number of florets per row over season indicated that sink strength or limitations at the source rather than a limited sink size was responsible for lower grain yield in unfavorable seasonal environments. The stability of 15 hybrids, as estimated by regression analysis, was found to be different for kernels per row and filled ear length but not for grain yield. Additive genes were responsible for the stability of the corn hybrids. The relative stability of a hybrid could be predicted by the regression coefficients of combining ability effects. The response of GCA effects to environments was basically a response to the cyclical change in solar radiation in seasonal environments. Therefore, it would be possible to identify genotypes tolerant to light stress by testing a large number of genotypes and selecting genotypes with high stability in seasonal environments where solar radiation is a major limiting factor for corn growth. Under different geographic environments, growth of corn was influenced by temperature, day length and day length sensitivity of the genotypes. Average number of days to mid-silking of 45 hybrids ranged from 50 at Waimanalo, Hawaii to more than 80 at Kamuela, Hawaii and at the temperate areas of Ames, Iowa, and Suweon, Korea. Additive and non-additive genes contributed to the genetic variation of the ear characters with significant effects of additive x location interaction as in seasonal environments. The high GCA/SCA ratio for all ear characters and grain yield indicated that GCA was more important than SCA for all characters. In general, the temperate inbreds CI21E, Mol7 and 0h545 were good combiners for kernels per row and filled ear length, while the tropical inbreds CM105 and Tx601 were good combiners for kernels per ear with a high row number. Partial correlation coefficients indicated that kernel number was the most important determinant of grain yield at all locations. Hybrids among tropical inbreds had a high stability for kernels per row and filled ear length, while hybrids among temperate inbreds responded better to favorable environments. Several hybrids between temperate and tropical inbreds showed higher stability as well as higher kernel number, longer ear length and higher grain yield than hybrids among tropical or temperate inbreds alone. Regression analysis of GCA effects showed that all tropical inbreds contributed to high stability in their hybrids. The hybrid x location interaction was mainly due to the linear response of GCA effects to different locations while SCA effects appeared to be stable from location to location. Generation mean analysis of 6 crosses among 4 inbreds showed that the dominance gene effects were the most important contributors to the inheritance of floret number, kernels per row, cob length and filled ear length. Additive gene effects were of minor importance in 6 crosses studied. Genetic variances were smaller than environmental variance for all characters. Average narrow sense heritability estimates were 39 % for floret number and 22 to 27 % for other characters. The minimum number of genetic factors was 3 for floret number and 5 to 8 for other three characters

Field-based phenotyping for the effects of high night-time temperature stress in wheat and maize

Doctor of PhilosophyDepartment of AgronomyAllan K FritzS.V. Krishna JagadishAbiotic stresses can differentially alter a plant’s physiology, phenology, yield and quality when coincided with different growth and developmental stages in crops. Along with varying responses due to the time of imposition, the type of abiotic stress (e.g., drought, nutrient, heat, or cold) and the duration of exposure can have differential level of impact. Under a changing climate, increasing temperatures are shown to result in significantly negative impact on crop yield and grain quality. While high day-time temperature stress has been thoroughly researched during the vegetative, reproductive, and grain-filling stages of major crops including wheat (Triticum aestivum L.) and maize (Zea mays L.), the effects of high night-time temperature stress are much less known. The grain-filling period in winter wheat and maize occurs during the summer and hence is hypothesized to be the most susceptible phase to high night-time temperature stress in Kansas under future warming scenarios. As such, this dissertation aims to explore the agronomic and physiological responses, and changes in grain quality and micronutrient composition on exposure to high night-time temperature stress during the grain-filling period of two major cereals grown under field conditions. To address the above objective, the first North American field-based high throughput phenotyping infrastructure for high night-time temperature stress had to be developed. This dissertation will detail the process of developing a small field-based prototype tent system (Chapter 2), the expansion of this methodology into the large field-based infrastructure (Chapter 3), and, finally, the alteration of this methodology to facilitate the phenotyping of large stature crops (Chapter 5). The field-based experiments were successful in applying a dynamic and equally distributed 3.2 and 3.8 degrees C high night-time temperature stress in the prototype tents and large field-based infrastructure, respectively. This application of high night-time temperature stress significantly affected the phenology of wheat by advancing the onset of senescence by about 3 days, averaged across 12 different genotypes. The rate of senescence was not affected in maize as the strong stay-green traits in modern hybrids allowed the seeds to reach physiological maturity before the onset of senescence. Agronomically, winter wheat was significantly affected through a reduction in grain yield in both the prototype and large field-based infrastructure (20% and 14%, respectively) as well as a reduction in 200 kernel weight (7% and 5%, respectively). Similarly, high night-time temperature stress on maize resulted in 14% reduction in total yield and an 8% reduction in 200 kernel weight, averaged across 12 commercial hybrids. Seed quality and micronutrient composition was significantly modified due to the application of stress with significant alterations observed in starch, protein, and nutrient content in both winter wheat and maize (Chapter 4 and 5, respectively). Using a susceptible and tolerant maize hybrid, differentially expressed genes governing starch metabolism were analyzed to understand the genomic basis of high night-time temperature resilience for starch synthesis. The evidence for a future climate which is prone to a higher level of variability has been confirmed through extensive climate-based modelling approaches. These predictions paired with the results of our current studies on high night-time temperature stress impacts, provides evidence for warming nights to have a significant negative effect on yield and quality in cereals. This dissertation is a compilation of the first-steps into phenotyping for high night-time stress impacts under field conditions which could be the basis for developing crop varieties/hybrids that can thrive under future uncertain climate

Equine obesity: concepts and mechanisms

Obesity in the UK leisure population of horses and ponies is a growing problem with major welfare implications. To date, research into the associations between obesity and metabolic disease such as insulin dysregulation and laminitis remain ongoing. To improve our understanding of obesity in this species, the current thesis was designed to address several related objectives ranging from psychological aspects of obesity to the role of key determinants of energy balance in the setting of obesity. Implementing dietary restriction to reverse obesity requires an owner to correctly recognise obesity in their animal, knowledge of which is lacking for the horse. A two-tier internet-based questionnaire was created and distributed through UK equine-based forums. Tier 1 utilised lateral photographic images of horses and ponies and demonstrated that only 11% of respondents (n = 546 total) correctly identified all overweight animals from a panel of 12 images. When assessing the suitability of horses and ponies for taking part in a range of activities, respondents considered it more appropriate for each animal to carry more weight/condition for competing in affiliated showing classes. Tier 2 (n = 177 responses) provided information regarding current management practices of horse-owners in the UK. The ability to quantify internal adiposity in live animals requires imaging technology which is not yet available for the horse. A semi-quantitative regional adipose-depot specific scoring system (EQUIFAT) was developed and tested. Associations between ante-mortem body condition score (BCS) and post-mortem EQUIFAT scores (n = 207 animals) revealed that retroperitoneal EQUIFAT score had strong positive associations with BCS, whilst omental had weaker associations and mesenteric and epicardial scores had no associations with BCS, indicating clear functional differences between regional adipose depots in the horse. Performing in-depth molecular biology studies using abattoir-derived samples requires knowledge of the time-frame of RNA degradation. RNA was found to remain intact up to 30 minutes and 2 hours post-mortem for adipose tissue and skeletal muscle ( n = 3 horses), respectively. The expression of myostatin, a key regulator of skeletal muscle mass and energy balance was evaluated in lean and obese horses and ponies (n = 6/group). Myostatin gene expression was increased in skeletal muscle of obese animals, with no difference at the protein level. Circulating myostatin concentrations were increased in obese animals. Adipocyte area was increased in adipose depots (retroperitoneal, omental, crest and tailhead) in obese animals, except for epicardial WAT. The expression of lipolytic proteins PLIN1 and HSL was reduced in retroperitoneal WAT of obese animals, with fewer differences noted between groups for other depots. Together, findings from this thesis indicate a misperception of obesity exists among horse-owners and enthusiasts. Functional differences between regional adipose depots and altered expression of key regulators of energy balance have been identified in obese horses and ponies