yes / A comprehensive experimental programme was performed with the focus on assessing the effects of compaction delay and ambient temperature on the physical, mechanical and hydraulic properties of lime treated expansive clays. Specimens were mellowed for a period of 0, 3, 6, 12, 24 and 48 h at two different temperatures of 20°C and 40°C prior to being compacted, tested and/or cured for up to 28 days for evaluating the impacts on long-term strength development. All specimens were prepared with the same dry unit weight of 12.16 kN/m3 and moisture content of 40% except for tests aimed at determining dry unit weight as a function of mellowing period. The results revealed that as the mellowing duration increased the dry unit weight declined remarkably at both temperature within the first 12 h. In addition, higher reduction rate was observed when specimens were mel-lowed at a temperature of 40°C. A 97% reduction in swelling pressure was obtained when the specimens were compacted upon mixing (zero hour mellowing period) and left to cure for 24 h prior to testing. Permeability coefficient of lime treated expansive clays was increased by up to 40 times when compaction was delayed for 24 h or when specimens were mellowed at 40°C. Specimens mellowed at a temperature of 40°C showed rela-tively stable values of permeability coefficient over the measurement period which could be attributable to accelerated pozzolanic reaction. The Unconfined Compressive Strength tests revealed that strength of lime treated expansive clays is significantly affected by compaction delay. An increase of 234% and 282% in the Unconfined Compressive Strength was achieved after 24 h of mixing with no compaction delay at 20°C and 40°C respectively. Gradual long-term gain in strength was observable within the 28 days post mixing but the rate of strength gain becomes slower and independent of temperature after the first 24 h of mixing. The results sug-gested that the four key reaction mechanisms occur concurrently with the first 12–24 h after lime addition recognized as being the most crucial period of time. Damaging the cementitious compounds by delayed com-paction is harmful to strength and restraining of swelling potential of lime treated expansive clays.

Ambient temperature sensing plays an important role in a number of applications in agriculture, industry, daily health care. In this thesis project, we propose a new acoustic-based ambient temperature sensing method called Mtemp. Mtemp empowers acoustic-enabled IoT devices, smartphones to perform ambient air temperature sensing without additional hardware. Basically, Mtemp utilizes on-board speaker and microphone to calculate the propagation speed of acoustic signal by measuring the phrase of the target signal, thereby estimate the ambient temperature according to a roughly linear relationship between temperature and sound speed. Mtemp is portable and economical, making it competitive compared with traditional thermometers for ubiquitous sensing.

One potential alternative to chemical weed control is the use of microwave radiation, a particular form of indirect thermal weeding. Absorption of microwave radiation causes water molecules within the tissue to oscillate, thereby converting electromagnetic energy into heat. This technique is rapid, versatile and effective, as the electromagnetic waves heat the plant tissue and destroy cellular integrity. The objective of this research was to evaluate the potential use of dielectric heating for weed management. Ten weed species representing monocots and dicots were selected for this study: southern crabgrass, dallisgrass, yellow nutsedge, fragrant flatsedge, false green kyllinga, common ragweed, field bindweed, henbit, white clover, and pitted morningglory. There was a lag or warm up period between energizing the magnetron and actual microwave radiation production. To eliminate the gap between electric power supplied to magnetron and actual microwave radiation produced, a conveyer was used. Overall injury to grasses, sedges and broadleaf weeds was higher at each dose when weeds were treated by microwave radiation while moving on a conveyer in comparison to being stationary. Grasses showed slightly more tolerance to microwave treatments in comparison to broadleaf weeds. Older weeds (8 to 10 weeks old) showed more tolerance to microwave treatments in comparison to younger weed plants (4 to 6 weeks old). Microwave radiation was able to control a range of weed species, although larger weeds were more likely to regrow after treatment. Ambient temperature had a significant effect on injuries caused by microwave radiation to target weeds, with control increasing as the air temperature increased. Weed control using microwave radiation required more energy when weeds were treated at 13 C compared to 35 C. More energy was needed at lower air temperatures to raise the plant canopy temperature from ambient levels to beyond the biological limit. Microwave radiation at lower doses caused greater injury to common chickweed and yellow woodsorrel than bermudagrass, suggesting the potential for selective weed control in certain situations. A custom built microwave applicator provided similar control of emerged weeds as the contact herbicides diquat and acetic acid. / Ph. D.

Master of Agribusiness / Department of Agricultural Economics / John A. Fox / The cost of wheat is the largest input cost for a flour mill, and as a result, profitability in wheat flour milling is determined in large part by milling efficiency – i.e., the amount of flour extracted per unit of wheat milled. In this project the objective was to quantify the influence of several measurable variables on flour mill efficiency. Data was collected from two commercial milling units of similar size. Linear regression was then used to estimate the relationship between flour yield and variables measuring grain characteristics and environmental factors. The analysis suggests that increasing ambient temperature and the occurrence of downtime both have a significant negative effect on flour yield. A significant difference in flour yield efficiency was also found between the two mills.

This thesis presents models that describe the behaviour of electricity demand and ambient temperature. Important features of both variables are described by mathematical components. These models were developed to calculate the value of electricity demand that is not expected to be exceeded more than once in ten years and to generate synthetic sequences that can be used as input data in simulation software. / PhD Doctorate

The development and transition of optical fiber sensors from experimental stage to practical applications largely depends on manufacturing cost and simplicity. To date, in-fiber grating sensors are largely manufactured by ultraviolet lasers despite higher fabrication cost and complexity. Besides, ultraviolet radiation can only write gratings in doped fibers. Therefore, reaping the benefits of existing fibers such as pure silica fiber, photonics crystal fibers etc. cannot be achieved using this technique. In contrast, uses of ultra-fast lasers have the potential to eliminate or minimize those drawbacks. However, extensive fabrication and packaging research is required for ultrafast laser technology to mature and offer grating based sensors fabrication in industrial scale. This dissertation presents design and fabrication of fiber optic sensors using femtosecond laser for measurement of ambient refractive index and temperature. The femtosecond laser operating at 780 nm with pulse duration of 172 fs and pulse repetition rate of 1 kHz is used to study bulk index modification and fabricate fiber long period and short period gratings. Effective and reliable fabrication of in-fiber gratings requires spatial control of refractive index written in optical fiber. With an aim to better control spatial index modulation in direct ultrafast writing, primary focus of this work is given to write single-shot submicron periodic voids in bulk glass. Femtosecond pulse filamentation in glass is studied to understand the morphology of bulk index change written by ultrashort pulses. Laser writing parameters (such as beam diameter, pulse energy, scanning speed, depth of focus, etc.) are then further tuned to write pulse filamentation induced refractive index change in optical fibers suitable for fiber grating fabrication. In order to design and tailor grating’s spectrum, measurement of in-fiber index is introduced in this work. We propose fiber Bragg grating based Fabry-Perot cavity structure (cavity length, L= 10 mm) to characterize femtosecond pulse filamentation induced refractive index change in the core of standard SMF. In addition, Mach-Zehnder interferometer (MZI) is proposed as an alternative yet effective and low cost tool to measure in-fiber index change. Comsol simulation is used to validate the quantification of index change. Measured index change is used in Optiwave simulation to design fiber long period gratings in standard telecommunication and pure silica core fibers. To increase fabrication reliability, we introduce inscription of helical long period gratings using a custom made rotary stage. Tapered photonic crystal and microfiber based Mach-Zehnder interferometer is also investigated for ambient refractive index measurement. Miniature fiber Bragg grating written in microfiber Mach-Zehnder interferometer is used in this work for multi-parameter sensing as well as temperature compensated refractive index sensing. Microfiber Bragg gratings buried in materials of higher thermal expansion coefficient is also proposed to significantly enhance temperature sensitivity. / Graduate / 0548, 0794, 0775 / fariduvic@gmail.com

Background: Preterm birth is a global health problem which causes significant short- and long-term morbidity and mortality. Pathophysiology is not entirely clear and due to climate change environmental risk factors, such as extreme temperatures, should be considered as emerging and modifiable risk factors. The evidence from low- and middle-income countries on their role is limited.  Objective: The goal of this study was to assess the relationship of daily mean temperature and number of preterm births in the period from March 2019 to May 2020 in Nepal.  Methods: Perinatal data from nine Nepalese hospitals, which took part in two recent quality improvement studies, was matched with climate data from 15 temperature stations. A time- series analysis using conditional Poisson regression and distributed lag non-linear models was done for the three stations with the largest study populations.  Results: Across the three analyzed regions in Nepal heterogenous results were found. Only in one area an overall increase in preterm birth risk for high temperatures within the last 2 weeks before delivery was found. One region showed a protective effect for heat, but increased risk for low temperatures. In the third region there was no overall association of ambient temperature and risk of preterm birth.  Discussion: Potential explanations for the heterogenous results are different sociodemographic and geographical background of the participants. Limitations concerning the selected study population as well as quality of climate data should be mentioned. Further studies are needed for more detailed investigation.

Studies of the adverse impacts of high temperature on human health have been primarily focusing on urban areas, due in part to the facts that urban centers generally have higher population density and are often significantly warmer than its surrounding rural areas (Heat Island Effect), and thus urban areas are considered to be more vulnerable to summer heat. However, heat vulnerability can also be affected by other population characteristics such as age, education, income and social isolation, which are likely to mark greater vulnerability among rural population. Here we explore the vulnerability to heat-related mortality in rural areas through a systematic review and meta-analysis of existing evidence. We searched studies that examined the association between high ambient temperature and morality in rural areas published in English between 2000 and 2016. Heat-mortality effect estimates from selected studies are grouped into two: (1) Rural effect estimates (RRrural) and their corresponding urban effect estimates (RRurban), from studies that reported risk estimates for both urban and their surrounding rural areas (7 studies included); (2) Rural effect estimates only (12 studies included). For Group 1, we performed a meta-analysis of the ratio of the rural estimate to the urban estimate in order to compare the magnitude of effects in rural versus urban areas. For Group 2, we performed a meta-analysis of the effect estimates in rural areas only. The pooled ratio estimate (RRrural/RRurban) for Group 1 is 1.051 (95% CI: 0.954, 1.160), which indicates the rural relative risk is about 5% larger than the urban relative risk. The pooled estimate for Group 2 is 1.191 (95% CI: 1.13, 1.251). Our preliminary results suggest that vulnerability to heat in rural areas may be similar to or even higher than urban areas, indicating that more studies are needed to understand rural vulnerability to heat-related hazards.

Combined cycle power plants haven becoming one of the mainstream power plants in the twenty-one century. The emergence of high 600¢J exhaust temperature of the gas turbine, due to the recent rapid enhancement of aerospace material and blade cooling methods, upgrades the gas turbine from low efficiency dual pressure non-reheat unit to high efficiency triple pressure reheat combined cycle power plants. In addition, the increase of turbine inlet temperature by 10~15¢J every year leads to the renewal of the advanced models gas turbine less than ten years. There are three-turbine inlet temperature (TIT) definitions in the gas turbine: (1) TA defines firing temperature as the mass flow mean total temperature before the first-stage stationary diagram edge plane.( Westinghouse or MHI product) (2) TB defines fire temperature as the mass flow mean total temperature at the first-stage nozzle trailing edge plane, ( GE product). (3) TC defines ISO firing temperature; it is a stoichiometric combustion temperature. It is not a physical temperature. ( Siemens ¡® Alstom ABB product). This study shows how to calculate compressor inlet mass flow balance, turbine power balance and heat balance on the combustion chamber system. In order to prove correctness of the balance equation, the data are taken from the heat balance diagram and acceptance test of Nan-pu power station combined cycle. The result shows that the study is sultable for application of the optimum analysis for CCPP operation performance. This type of combined cycle power plant suits not only for the base-load but also for the cycling-load operation.

Gram-positive bacteria are part of the normal flora of fish from different aquatic environments. They are mesophilic bacteria and demonstrate optimum growth at ambient temperature. In the sub-tropics, marine fish are caught from seas at temperatures of 16 to 34C, they are usually not iced and are handled at ambient temperature. It was hypothesized that under these conditions Gram-positive bacteria will be abundant in sub-tropical marine fish and will have roles in the spoilage of fish. A review of literature showed that there is a gap in understanding the Gram-positive bacterial populations in sub-tropical marine fish. This is partly due to the fact that the selective media used for isolating Gram-positive bacteria have limitations. Ecological and speciation studies have revealed that the ecology and speciation of many Gram-positive bacteria have not been clearly elucidated. The effect of ambient storage on the individual genera and species of Gram-positive bacteria in fish has been rarely studied. The spoilage potential of Gram-positive bacteria of marine fish origin has not been clearly determined. Therefore, the main aims of this study were to isolate Gram-positive bacteria from fresh and ambient-temperature-stored sub-tropical marine fish, speciate the isolates and study the spoilage potential of the isolates. The practical components of this study were conducted in four parts. The first part dealt with validation of tryptone soya agar with 0.25% phenylethyl alcohol (PEA-TSA) to enumerate Gram-positive bacteria. The second part enumerated Gram-positive bacteria from the muscles, gills and gut of Pseudocaranx dentex (Silver Trevally), Pagrus auratus (Snapper) and Mugil cephalus (Sea Mullet) stored at 25C for 15 hours using PEA-TSA. The third part dealt with the speciation of the isolates using appropriate methods such as polymerase chain reaction, 16S rRNA gene sequence, the VITEK JR system and conventional biochemical methods. In the fourth part, the isolates were assayed qualitatively for their ability to produce volatile sulphur compounds (VSC), reduce trimethylamine oxide and decarboxylate histidine, lysine and ornithine at mesophilic temperature, 32C. Initial studies indicated that PEA-TSA significantly (P< 0.05) reduced the total aerobic bacterial count of fish whereas control Gram-positive bacteria were not affected (P> 0.05). Gram-positive aerobic bacterial counts (GABC) significantly (P< 0.05) increased in the muscles and gills during ambient storage for 15 hours. Within each species, no significant (P> 0.05) differences were found in GABC between muscles and gills. Moreover, there were no significant differences (P> 0.05) in GABC between fish species during storage. In total, 390 bacteria were isolated from the fresh and stored fish; 339 isolates (87%) were found to be Gram-positive. Two hundred and sixty-six isolates (78%) of Gram-positive bacteria were identified to fall into 13 genera, namely Staphylococcus, Micrococcus, Bacillus, Virgibacillus, Brevibacillus, Corynebacterium, Streptococcus, Enterococcus, Aerococcus, Exiguobacterium, Carnobacterium, Vagococcus and Sporosarcina and 30 species. In fresh fish, Staphylococcus epidermidis and Micrococcus luteus were the most frequent isolates. The effect of storage at 25C for 15 hours resulted in a change of Gram-positive bacterial populations; while S. epidermidis, S. xylosus and Bacillus megaterium were no longer present, S. warneri, B. sphaericus, Brevibacillus borstelensis, Enterococcus faecium and Streptococcus uberis increased. Three species, E. faecium, Str. uberis and B. sphaericus, were the most prevalent at the end of storage. Micrococcus luteus and S. warneri were the most prevalent isolates from Pseudocaranx dentex, but E. faecium and Str. uberis were the most frequently isolated from Pagrus auratus and Mugil cephalus. With respect to different parts of the fish body, E. faecium, Str. uberis and B. sphaericus were the most frequent isolates from the muscles, E. faecium, Str. uberis from the gills and M. luteus from the gut. Among the 228 isolates examined, Br. borstelensis 73, Br. borstelensis 291, Str. uberis 339, Vagococcus fluvialis 31 and Vag. fluvialis 132 produced VSC from sodium thiosulphate, cysteine and methionine. However, strains varied in sulphur source utilization. Exiguobacterium acetylicum 5, Exiguobacterium spp. 191, Carnobacterium spp. 338, Br. borstelensis 73, Br. borstelensis 291, Str. uberis 30, Str. uberis 339, Vag. fluvialis 31 and Vag. fluvialis 132 reduced TMAO. No histidine decarboxylase activity was found in the Gram-positive bacterial species tested. Lysine and ornithine were decarboxylated mainly by different strains of S. warneri, S. epidermidis and M. luteus. During ambient storage of fish, the frequency of lysine-decarboxylating bacteria increased and became more diverse after 5 hours of storage. Among fish species examined, the frequencies of lysine- and ornithine-decarboxylating bacteria were higher and more diverse in Pseudocaranx dentex than in Pagrus auratus and Mugil cephalus. This study found that Gram-positive bacteria were abundant and diverse in sub-tropical marine fish; however, their frequencies were affected by fish habitat and fish body part. Ambient temperature storage determined which Gram-positive bacterial species were dominant. With the exception of one isolate of S. aureus, Gram-positive bacteria isolated from sub-tropical marine fish caught from unpolluted water were not potential pathogens. The study also showed that Gram-positive bacteria had greater ability to decarboxylate lysine and ornithine than to produce VSC or reduce TMAO, and the spoilage potential of a bacterial species was a strain-dependent behaviour. This is a significant study as it is the first study on this aspect sub-tropical marine fish. It validated a selective medium that can be used to enumerate most Gram-positive bacteria from a marine environment. Most of the Gram-positive bacterial species from sub-tropical marine fish identified in this study were documented for the first time. The effects of ambient storage and the spoilage potential of Gram-positive bacteria from sub-tropical marine were clearly elucidated.