Biocementation of an Organic Soil with Electrokinetics

This thesis assesses the feasibility of biocementation of a problematic organic foundation soil of many embankments of the East Anglia railway network. Biocementation has recently attracted the interest of the researchers worldwide as an emerging soil stabilisation technique, proposed as environmentally friendlier and more sustainable than other soil stabilisation techniques; however, evidence of its effectiveness as a stabilisation technique for soils other than sands is limited. In this research indigenous, non-pathogenic and ureolytic bacterial strains were screened and isolated from the in situ soil. Four strains (Bacillus licheniformis, Rhodococcus erythropolis, Micrococcus luteus, and Lysinibacillus fusiformis) were selected based on their ability to grow at different temperatures, pH, soil moisture content and to precipitate CaCO3 through urea hydrolysis. For the implementation of the biocementation treatment, laboratory scale models were designed for pressure flow column and electrokinetic injection. The latter method was of particular interest in this study as a potential in situ implementation method under existing embankments. After a first series of pressure flow soil column experiments, with all strains, which studied parameters such as bacterial population and cementation reagent concentration and curing time. Following these, the best performing strain (Bacillus licheniformis) in terms of Unconfined Compressive Strength (UCS) and CaCO3 precipitation (in the flow column tests) was used for further testing and the electrokinetic experiments. Unconfined Compressive Strength (UCS) and oedometer testing results supported by CaCO3 measurements, NH4 + concentration measurements and pH change measurements, as well as microstructural SEM-EDS analysis, proved that biocementation did occur for both implementation methods and for a number of treatment combinations. EK was the most successful implementation method and was proven effective for degrees of saturation of 85-95%. Whilst treatment non-uniformity when bacteria were injected electrokinetically still needs to be addressed, there is promise that EK could be a viable technique for treating foundation soil under existing infrastructure, which is a major challenge for engineers

Human Resource Practices and Job Performance in Pakistan, Analysis of a Hypothesized Model

Human resource management is an emerging field of study in Pakistan. The purpose of this study is to identify the best human resource practices in the context of Job performance and offer recommendations for future research. This study reviewed many published articles in the major academic journals, focusing on the most important human resource practices, the relations between human resource practices and job performance. This study finds that Pakistan-based research on the human resource practices has been actively discussed in the major theoretical debates in the literature, and that Pakistan-based studies have extended previous models by identifying additional intervening variables. A hypothesized model on the basis of extensive review of the literature has been developed. It is recommend that future research in this area be more responsive to emerging methodological concerns of the field, and pay more attention to Pakistan-specific issues that may have significant organizational consequences

Software and hardware implementation techniques for digital communications-related algorithms

There are essentially three areas addressed in the body of this thesis. (a) The first is a theoretical investigation into the design and development of a practically realizable implementation of a maximum-likelihood detection process to deal with digital data transmission over HF radio links. These links exhibit multipath properties with delay spreads that can easily extend over 12 to 15 milliseconds. The project was sponsored by the Ministry of Defence through the auspices of the Science and Engineering Research Council. The primary objective was to transmit voice band data at a minimum rate of 2.4 kb/s continuously for long periods of time during the day or night. Computer simulation models of HF propagation channels were created to simulate atmospheric and multipath effects of transmission from London to Washington DC, Ankara, and as far as Melbourne, Australia. Investigations into HF channel estimation are not the subject of this thesis. The detection process assumed accurate knowledge of the channel. [Continues.

Opioids Delay Healing of Spinal Fusion: A Rabbit Posterolateral Lumbar Fusion Model

Background Context Opioid use is prevalent in the management of pre- and postoperative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in vitro, and a previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that closely mimics humans. Purpose The objective of this work was to study the effect of systemic opioids on the process of healing of spinal fusion in a rabbit posterolateral spinal fusion model. Study Design/Setting This is a preclinical animal study. Materials and Methods Twenty-four adult New Zealand white rabbits were studied in two groups after approval from the Institutional Animal Care and Use Committee (IACUC). The opioid group (n=12) received 4 weeks\u27 preoperative and 6 weeks\u27 postoperative transdermal fentanyl. Serum fentanyl levels were measured just before surgery and 4 weeks postoperatively to ensure adequate levels. The control group (n=12) received only perioperative pain control as necessary. All animals underwent a bilateral L5–L6 posterolateral spinal fusion using iliac crest autograft. Animals were euthanized at the 6-week postoperative time point, and assessment of fusion was done by manual palpation, plain radiographs, microcomputed tomography (microCT), and histology. Results Twelve animals in the control group and 11 animals in the opioid group were available for analysis at the end of 6 weeks. The fusion scores on manual palpation, radiographs, and microCT were not statistically different. Three-dimensional microCT morphometry found that the fusion mass in the opioid group had a lower bone volume (p=.09), a lower trabecular number (p=.02), and a higher trabecular separation (p=.02) compared with the control group. Histologic analysis found areas of incorporation of autograft and unincorporated graft fragments in both groups. In the control group, there was remodeling of de novo woven bone to lamellar organization with incorporation of osteocytes, formation of mature marrow, and relative paucity of hypertrophied osteoblasts lining new bone. Sections from the opioid group showed formation of de novo woven bone, and hypertrophied osteoblasts were seen lining the new bone. There were no sections showing lamellar organization and development of mature marrow elements in the opioid group. Less dense trabeculae on microCT correlated with histologic findings of relatively immature fusion mass in the opioid group. Conclusions Systemic opioids led to an inferior quality fusion mass with delay in maturation and remodeling at 6 weeks in this rabbit spinal fusion model. These preliminary results lay the foundation for further research to investigate underlying cellular mechanisms, the temporal fusion process, and the dose-duration relationship of opioids responsible for our findings

The Temporal Expression of Adipokines During Spinal Fusion

Background Context Adipokines are secreted by white adipose tissue and have been associated with fracture healing. Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Purpose Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Study Design The study design included a laboratory animal model. Methods New Zealand white rabbits were assigned to either sham surgery (n=2), unilateral posterior spinal fusion (n=14), or bilateral posterior spinal fusion (n=14). Rabbits were euthanized 1–6 and 10 weeks out from surgery. Fusion was evaluated by radiographs, manual palpation, and histology. Reverse transcription-polymerase chain reaction on the bone fusion mass catalogued the gene expression of leptin, adiponectin, resistin, and vascular endothelial growth factor (VEGF) at each time point. Results were normalized to the internal control gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (2^ΔCt), and control bone sites (2^ΔΔCt). Quantitative data were analyzed by two-factor analysis of variance (p\u3c.05). Results Manual palpation scores, radiograph scores, and histologic findings showed progression of boney fusion over time (p Conclusions Leptin expression is likely associated with the maturation phase of bone fusion. Adiponectin and resistin may play a role early on during the fusion process. Our results suggest that leptin expression may be upstream of VEGF expression during spinal fusion, and both appear to play an important role in bone spinal fusion

AN ANALYSIS OF INTERMODAL INFORMATION TECHNOLOGY USAGE BY INTERMODAL PORTS AND TERMINALS IN THE AGRICULTURAL AND FOOD- PRODUCT MARKET

Agribusiness, Research and Development/Tech Change/Emerging Technologies,

A comparative study of Pakistani and British press regarding the framing of Afghanistan war 2001

This study analyzed how Afghanistan war 2001 was framed by Pakistani and British press. What frames were employed by the newspapers of these two countries in the reporting of Afghanistan attack.For this purpose four newspapers were chosen from Britian and Pakistan namely The Dawn, The Nation, The Independent and The Guardian.The editorilas of these newspapers were analysed by employing the technique of thematic analysis. By analysing the data, it was found that Pakistani and British press mostly framed the coverage of Afghanistan war in a negative stance but at certain points Britsh press adopted positive or neutral stance.Anti war frame was dominnently employed by Pakistani newspapers but humanitrian and rebuilding frames were also observed.Likewise, Britsh press mostly covered Afghanistan under anti war frame but at some points pro war frame was also observed.Overall, it was noted that Pakistani press was more dominated by opposotional and critical themes than British newspapers

Innovative methods of ground improvement for railway embankment Peat Fens foundation soil

The aim of this research was to assess the feasibility of biocementing a problematic foundation soil of railway embankments from Peat Fens in East Anglia, UK. Biocementation of soil is an emerging, novel ground improvement technique. It has recently attracted the interest of researchers worldwide because it has been proposed as potentially environmentally superior to chemical grouts and other common soil stabilisers e.g. cement or lime (linked to high CO2 11 emissions). In this study we screened and isolated non-pathogenic indigenous ureolytic microbial candidates with potential for biocementation from samples originating from Peat Fens in East Anglia, UK. Four strains were selected as the most suitable candidates, based on their growth rate and their viability in a wide range of temperatures, pH and soil moisture contents corresponding to typical seasonal field conditions. After a number of Unconfined Compressive Strength (UCS) tests, one strain (Bacillus licheniformis) was selected as the most promising for this soil treatment and used for further study. Two different methods of implementation of the treatments were considered, namely pressure flow soil column and electrokinetic injection. The UCS results supported by CaCO3 measurements as well as microstructural SEM-EDS analysis proved that biocementation did occur for both implementation methods and for a number of treatment combinations. Ongoing work on optimisation of treatments and implementation methods is carried out towards the upscaling of the techniques for in situ implementation which is planned for the next stage of the research