Design and Fabrication of All Organic Field Effect Transistor

All organic field effect transistor consist of poly-3-hexyloxythiophene, undoped poly-3,3”-didecyl-2,2’,5’,2”-terthiophene and polypyrrole has been successfully developed. Poly-3-hexyloxythiophene was applied as gate material. Undoped poly-3,3”-didecyl-2,2’,5’,2”-terthiophene was used as insulating layer and polypyrrole was applied as source-drain material. The multilayer polymers were deposited onto gold source-drain and gate electrodes by electropolymerization method. The spaces between the gold electrodes were 50 μm. The transistor shows a current amplification upon increasing gate voltages. Good conductivity stability upon increasing gate voltages was observed. Overall the field effect transistor has properties that similar to inorganic field effect transistor

Development of methods for the analysis of petroleum contaminated soils

Soil contamination from petroleum spills is a frequent environmental problem in the world. It is obvious that petroleum exploration has contributed immensely to the economic growth of Nigeria, but over the last few decades, the Niger Delta of Nigeria has suffered grave human health risk and ecosystem degradation resulting from oil spillages, petroleum products leakages and other involuntary effluent discharges from oil exploration activities. This research seeks to develop and optimize GC-FID methods for the analysis of Petroleum hydrocarbons. Crude oil spillage contamination of soil from the Niger Delta was investigated 3 months after a crude oil-pipeline spillage. 47 Soil samples (300-500g) were collected at several points in the South-South Niger Delta. Control samples were taken from four unaffected sites within the vicinity of spillage with similar soil characteristics. Samples were collected at depths of 0-15 cm, 15-30 cm and 30-60 cm. The soil samples were prepared for analysis using solvent extraction methods, passed through column of sodium sulphate and Florisil® to aid in column performance, remove moisture and gross impurities. Samples were analysed using gas chromatography with a flame ionisation detector. Penetration and migration of C10-C26 and C26-C34 hydrocarbons through the soil layers were assessed by cluster analysis to determine the spatial distribution, penetration and chemical similarity of these compounds over the contaminated area. This information is a useful guide for bioremediation purpose. It was found that total petroleum hydrocarbon concentrations varied from 9-289 mgkg-1 topsoil, 8-318 mgkg-1 subsoil and 7-163 mgkg-1 at the greatest depth measured.The results show elevated levels of total hydrocarbon contents when compared with the reference sites. Drastic steps should be taken to carefully monitor and remediate the environment. Bioremediation with plants and micro-organisms is endorsed.EThOS - Electronic Theses Online ServiceAKWA IBOM STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY, UYO, NIGERIAGBUnited Kingdo

Artificial Olfaction in the 21st Century

The human olfactory system remains one of the most challenging biological systems to replicate. Humans use it without thinking, where it can measure offer protection from harm and bring enjoyment in equal measure. It is the system's real-time ability to detect and analyze complex odors that makes it difficult to replicate. The field of artificial olfaction has recruited and stimulated interdisciplinary research and commercial development for several applications that include malodor measurement, medical diagnostics, food and beverage quality, environment and security. Over the last century, innovative engineers and scientists have been focused on solving a range of problems associated with measurement and control of odor. The IEEE Sensors Journal has published Special Issues on olfaction in 2002 and 2012. Here we continue that coverage. In this article, we summarize early work in the 20th Century that served as the foundation upon which we have been building our odor-monitoring instrumental and measurement systems. We then examine the current state of the art that has been achieved over the last two decades as we have transitioned into the 21st Century. Much has been accomplished, but great progress is needed in sensor technology, system design, product manufacture and performance standards. In the final section, we predict levels of performance and ubiquitous applications that will be realized during in the mid to late 21st Century

A Multi-Centre Study to Risk Stratify Colorectal Polyp Surveillance Patients Utilising Volatile Organic Compounds and Faecal Immunochemical Test

(1) Background: The service capacity for colonoscopy remains constrained, and while efforts are being made to recover elective services, polyp surveillance remains a challenge. (2) Methods: This is a multi-centre study recruiting patients already on polyp surveillance. Stool and urine samples were collected for the faecal immunochemical test (FIT) and volatile organic compounds (VOC) analysis, and all participants then underwent surveillance colonoscopy. (3) Results: The sensitivity and specificity of VOC for the detection of a high-risk finding ((≥2 premalignant polyps including ≥1 advanced polyp or ≥5 premalignant polyps) were 0.94 (95% CI, 0.88 to 0.98) and 0.69 (95% CI, 0.64 to 0.75) respectively. For FIT, the sensitivity was (≥10 µg of haemoglobin (Hb) / g faeces) 0.54 (95% CI, 0.43 to 0.65) and the specificity was 0.79 (95% CI, 0.73 to 0.84). The probability reduction for having a high-risk finding following both negative VOC and FIT will be 24% if both tests are applied sequentially. (4) Conclusion: The diagnostic performance of VOC is superior to FIT for the detection of a high-risk finding. The performance further improves when VOC is applied together with FIT sequentially (VOC first and then FIT). VOC alone or the combination of VOC and FIT can be used as a triage tool for patients awaiting colonoscopy within a polyp surveillance population, especially in resource-constrained healthcare systems

SEDIMENTOLOGY OF THE UPPER SCOTLAND FORMATION (EOCENE), BARBADOS

Representative samples collected from the Lower Scotland Formation (Eocene) outcropping in northeastern Barbados were investigated in conjunction with overall facies distribution and stratigraphic and sedimentological characteristics to interpret depositional environment and provenance of the fine-grained clastics. The Lower Scotland Formation is, for the most part, a fine-grained clastic-dominated sequence with occasional thin intercalations of gypsum, ironstone, and kaolinite. Distinctive deep-water-facies have been well-documented in dark gray shale units containing load cast, flutes, grooves and prods. In addition, turbiditic brown sandstone with a sharp erosive base and pelagic caps also characterize the base of the formation. Notable marine fauna observed include Nummulites, Orbitoids, and occasionally Discocyclina sp. The Lower Scotland Formation has been intensely folded and faulted and, in many places, shows a thrust contact with the Upper Scotland Formation. Preliminary compositional studies involved both light and heavy mineral separation, as well as thin section studies. Detrital minerals in the formation include quartz (both monocrystalline and polycrystalline), feldspar (mostly altered microcline), and altered biotite. Heavy minerals include zircon, monazite, tourmaline, rutile, kyanite, and augite. Lithic fragment of varied source rocks are also observed. Bulk chemical and trace element investigation of the selected samples suggests an overall trend of immobile traces including Sr, Ba, and Rb increasing up-section and an overall decreasing silica content up-section. The Northwestern Venezuelan Shield, located to the south of the study area, acted as the primary source of detritus for the Lower Scotland Formation, the latter being subjected to pronounced structural deformation in response to the Cenozoic Andean Orogenic episode