The purpose of this study is to develop the optimum design of fiber coupler package. Three different kinds of fiber coupler packages are investigated to understand the results of the optical properties under the environmental tests. The environmental test includes the temperature cycling, water immerse, and impact test. The results of fiber coupler packages will be accepted if the measurements for the optical properties are within a small range change under the environmental tests. There are so many components in fiber coupler packages that it is difficult to identify the specific components which should responsible for the optical property changes under environmental test. Therefore, a metallographic analysis is used to understand the structure change of fiber coupler package under environmental test. In this work, the optimum design of fiber coupler package are (1) a ceramic substrate, (2) the epoxy which bonding fiber and substrate should mixed with silicon powder, (3) the silicone should fill the empty space of steel tube fully, and (4) a good protection between the fiber and steel tube.

This research project aimed at evaluating four internationally accepted leachate extraction tests to determine their applicability on sewage sludge samples. Furthermore, the present analytical method to determine the leachable fraction of sludge for compliance to South African sludge legislation was evaluated. Leaching tests are done on sludge samples to determine element mobility. This is important since land application of sewage sludge is an accepted and regulated sludge management practice. A literature survey was done to evaluate the mobility over time of metals originating from sludge-amended soils. Mobility is initially due to the organic content of the soil and after organic matter decomposition, it is dependant on the inorganic content. Mobile metals in sludge-amended soil can cause potential environmental risks like groundwater contamination and metal accumulation in soil. Metal accumulation can further lead to increased plant uptake of metals. To determine the partitioning or fractionation of metals found in sludge-amended soil, selective sequential extractions and single extractions can be used. Since South African sludge legislation specifies a single extraction procedure, four were selected for comparative studies. The selected procedures were the USA Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure (TCLP) the Australian Standard Bottle leaching Test (AS 4439.3) the Nederlands Normalisatie-Insitiuut availability test (NEN 7341) and the Deutches Institut für Normung water leachability test (DIN 38 414-S4). A variation of the TCLP is specified for use in South Africa. Three sewage sludge sample lots were collected. The first consisted of 24 sub-samples that were collected from 24 different wastewater treatment works on the East Rand. Both leachable (TCLP) and total (aqua regia) extraction was done on these samples for Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Zn, Se, B and Fe. A relationship between the leachable and total extractions was found for Co and Pb but could not be tested by literature values due to a variation in the sample preparation. The TCLP leachates were also analysed by Atomic Absorption and Inductively Coupled Plasma techniques to compare the applicability of the two. It was found that both techniques are acceptable for leachate analysis. The second sample lot collected from a single wastewater treatment plant was used to determine the leachable effect of the difference between the South African adapted TCLP and the USA EPA procedure as well as the NEN procedure. The EPA specifies all samples be extracted on an “as is” basis while the South African adaptation specifies dry samples. It was found that no element was comparative between dry and wet sample for both extraction procedures. It was observed that wet extractions yield generally higher values than dry extractions. A third sample lot was collected two months after the second sample lot at the same wastewater treatment works. It was used to compare the four extraction procedures. From this it was found that the DIN yielded the highest results for the specified elements. This procedure could not be recommended since the experimental difficulties and the duration of the test make it an unsuitable regulatory compliance tests protocol. / Dissertation (MSc (Environmental Technology))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

<p>This master thesis is about investigation a power efficient anti-moisture device thatcan be implemented in electronic enclosures in severe climatic environments.First, some of the existing knowledge and previous works were introduced. Then arelevant theoretical background including three main approaches in humiditymanagement are described, comparison between the enclosure heaters and localheaters, some psychrometics concepts that have been used in the project, heattransfer fundamentals, environmental test basics, some humidity and temperaturesensing techniques, computational fluid dynamics, programmable logic controlfundamentals, comparison PLCs with microcontrollers was provided.A series experiments have been performed in order to find the power efficient andmost effective anti-moisture method. Based on the analysis of the experiment data,the local heater system has been designed. CFD assisted parametric study of thelocal heater has been performed in order to find the best feasible design includingthe size and location. The local heater has been built based on the results ofparametric study. Different materials have been tested in laboratory in order tofind the proper material for final prototype of heater. The implemented localheater has been integrated with programmable logic control device. The controlalgorithm has been developed for activation/deactivation of local heater. The logiccontrolled PCB local heater has been experimentally evaluated.In the end the results achieved from environmental test have been presented andanalyzed. Some conclusions on the results and also future work have been discussed.</p>