Novel CO(2)/N(2)O waveguide laser

We present a new design for a waveguide laser which is easily constructed from readily available materials. We have demonstrated its operation for CO(2) (8.5-W output) and N(2)O (1.5-W output).     

A Generative System for Mamluk Madrasa Form-Making

In this paper, a parametric shape grammar for the derivation of the floor plans of educational buildings (madrasas) in Mamluk architecture is presented. The grammar is constructed using a corpus of sixteen Mamluk madrasas that were built in Egypt, Syria, and Palestine during the Mamluk period. Based on an epistemological premise of structuralism, the morphology of Mamluk madrasas is analyzed to deduce commonalities of the formal and compositional aspects among them. The set of underlying common lexical and syntactic elements that are shared by the study cases is listed. The shape rule schemata to derive Mamluk madrasa floor plans are formulated. The sets of lexical elements and syntactic rules are systematized to form a linguistic framework. The theoretical framework for the formal language of Mamluk architecture is structured to establish a basis for a computerized model for the automatic derivation of Mamluk madrasa floor plans.     

Performance measurement of product returns with recovery for sustainable manufacturing

Today's lifecycle of new and emerging products, increase in labour costs in developed countries and user's expectations or behaviours including frequently upgrading items with latest features, influence the growth rate of product disposal to landfill. To reduce the negative impact on the environment, global manufacturers need to take responsibility for designing sustainable products and implementing cleaner production systems for 3R operations (3R–Reuse/Remanufacture/Recycle). Nevertheless, there is still a lack of comprehensive measures for assessing product returns with recovery settings. In this paper, a framework for performance evaluation using design for six sigma methodology is developed to estimate utilisation value of a manufactured product with recovery settings, which accounts for total recovery cost, manufacturing lead-time, minimisation for landfill waste and quality characteristic. Finally, a numerical example based on these performance attributes to assess product utilisation value is presented.     

Exploring the fitness landscape and the run-time behaviour of an iterated local search algorithm for cost-based abduction

Cost-based abduction (CBA) is an important problem in reasoning under uncertainty, and can be considered a generalization of belief revision. CBA is known to be NP-hard and has been a subject of considerable research over the past decade. In this paper, we investigate the fitness landscape for CBA, by looking at fitness–distance correlation for local minima and at landscape ruggedness. Our results indicate that stochastic local search techniques would be promising on this problem. We go on to present an iterated local search algorithm based on hill-climbing, tabu search, and simulated annealing. We compare the performance of our algorithm to simulated annealing, and to Santos' integer linear programming method for CBA.     

An integrated approach for groundwater potential zoning in shallow fracture zone aquifers

This study presents an integrated approach for the identification of groundwater occurrences in shallow fracture zone (SFZ) aquifers using remote-sensing, geological, and geophysical data. The Central Eastern Desert of Egypt was selected as a test site for the present study. The distribution of major faults and shear zones was extracted from a fusion image generated by injecting high-spatial resolution phased array L-band synthetic aperture radar (PALSAR) images into Landsat Enhanced Thematic Mapper images. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model was processed to extract the drainage systems, slope, and topographic wetness index (TWI). The multidate PALSAR imagery acquired during rainy and dry seasons was used to estimate the relative soil moisture content. The lithology, fractures, drainage density, slope, TWI, and soil moisture content were used as thematic layers for groundwater occurrence in the SFZ aquifers. A GIS model of groundwater potential was developed by selecting the most probable locations for groundwater in each layer. The results indicate that the spatial distribution of the existing water wells is in agreement with the model where all wells fall in the regions of high groundwater potential zones. A geophysical survey was conducted using ground penetrating radar (GPR), indicating that the high groundwater potential zones are promising for drilling shallow wells. The adopted approach can be used as a cost-effective tool for groundwater exploration in the SFZ aquifers in the study area and in areas of similar geologic and hydrogeologic settings elsewhere.     

Effect of thermal degradation on the impact properties of PVC compounds

An instrumented drop weight impact test was used to study the effect of thermal degradation on the impact properties of PVC compounds. The impact resistance of the aged compounds related well with their weight loss and hence, with thermal degradation. Each compound showed a specific weight loss percentage that correlated with a 50% loss in its impact properties (failure point), irrespective of the aging temperature. The results were also used to estimate a thermal index (TI) of each compound in a rapid and reliable way.     

Bioactive lipids and antioxidant properties of wild Egyptian Pulicaria incise, Diplotaxis harra, and Avicennia marina

Fatty acids, sterols and tocopherols profile of Pulicaria incise, Diplotaxis harra and Avicennia marina grown wild in Egypt were investigated. Linoleic acid followed by palmitic and oleic acids were the major fatty acids in P. incise. Oleic followed by stearic were the main acids in D. harra, while palmitic followed by oleic were the major fatty acids found in A. marina. Sterol markers of P. incise were campesterol followed by stigmasterol and β-sitosterol. In D. harra β-sitosterol followed by stigmasterol and ?5-avensterol were the major sterols, while campesterol followed by β-sitosterol and ?7-avensterol were main sterols of A. marina. Tocopherols were also estimated in high levels, wherein δ-tocopherol was the main tocopherol in all plants. Antioxidant properties of methanolic extracts of the plants were compared with methanolic solution of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and ascorbic acid during thiocyanate assay. Moreover, methanolic extracts of the whole plants exhibited strong antiradical potential against DPPH radicals. Information provided by the present study is of importance for further investigations of P. incise, D. harra and A. marina and utilization of these plants as a raw material of bioactive compounds.     

Development and optimization of ME-TVC desalination system

Significant and rapid developments have taken place recently in the multi-effect thermal vapor compression (ME-TVC) desalination system of SIDEM Company, particularly in enlarging the unit capacity. The new trend of combining ME-TVC with conventional multi-effect has allowed this unit capacity to increase from two to eight million imperial gallons per day (MIGD) in the last decade. This considerable increase in capacity, poses a real competition to the multi stage flash system (MSF) as a large-scale production plant with lower operation temperatures.A steady state mathematical model of the ME-TVC desalination system is developed in this paper using Engineering Equations Solver (EES) to evaluate the model system performance. The model validity is examined against three commercial ME-TVC units which showed good results. The main improvements in the performance during the past ten years are also outlined and discussed. Another purpose of this paper is to determine the optimum operating and design conditions of the ME-TVC desalination system through mathematical modeling optimization. A MATLAB algorithm solution is developed and used to solve model equations, where a different number of effects were tested to maximize the gain ratio using (1) Smart Exhaustive Search Method and (2) Sequential Quadratic Programming. Results showed that the maximum gain ratio varied between 8.5 and 18.5 for 4 and 12 effects with the optimal top brine temperature ranging between 55.8 and 67.5 °C and a reasonable specific heat transfer area. The optimal ranges of compression and entrainment ratios are between 1.81 to 3.68 and 0.73 to 1.65 respectively. The optimal results of 4-effect TVC unit are also compared with three commercial 4-effect units having almost the same input, which showed that further improvement in the distillate output production, compression and entrainment ratio can be achieved by combining the ME-TVC system with conventional multi-effect unit.     

The hydrometallurgical extraction of rhenium from copper industrial wastes

An attempt has been made in this investigation to develop a wet chemical method for treating a rhenium-containing lead slime produced during copper manufacture. The effects of temperature, grain size, oxygen partial pressure, and leaching time as well as the kinetics of the leaching process were studied.     

Conformance testing in systems with semicontrollable interfaces

In a conformance testing environment, an implementation under test (iut) communicates with multiple entities. A tester may have differing degrees of control on the interactions between these entities and the iut : directly controllable, semicontrollable, or uncontrollable. Semi-controllable inputs most likely render portions of an IUT untestable. In addition, multiple communicating entities may create race conditions during testing. This paper presents a test generation methodology for systems where the semicontrollable inputs can be generated indirectly. The test sequences obtained from the converted graph fully utilize the semicontrollable inputs (where possible) while avoiding the race conditions. Although, for the most general case, the graph conversion results in a exponentially large number of nodes, practical considerations make the converted graph size feasible. This approach is used to generate tests for mil-std 188-220B. By applying the proposed graph conversion and the race condition elimination techniques, the number of testable state transitions increased from approximately 200 to over 700, which represents a coverage of 95% of the transitions defined in the specification.