Phase Transformation Behavior of Porous TiNi Alloys Produced by Powder Metallurgy Using Magnesium as a Space Holder

Porous TiNi alloys with porosities in the range of 51 to 73 pct were prepared successfully applying a new powder metallurgy fabrication route in which magnesium was used as a space holder, resulting in either single austenite phase or a mixture of austenite and martensite phases dictated by the composition of the starting powders, but entirely free from secondary brittle intermetallics, oxides, nitrides, and carbonitrides. Since transformation temperatures are very sensitive to composition, deformation, and oxidation, for the first time, transformation temperatures of porous TiNi alloys were investigated using chemically homogeneous specimens in as-sintered and aged conditions eliminating secondary phase, contamination, and deformation effects. It was found that the porosity content of the foams has no influence on the phase transformation temperatures both in as-sintered and aged conditions, while deformation, oxidation, and aging treatment are severely influential.     

Self Organized Network Management Functions for Energy Efficient Cellular Urban Infrastructures

Energy efficiency is a significant requirement for the design and management of mobile networks and has recently gained substantial attention from both network operators and the research community. The general concept of energy saving management aims to match the capacity offered by operators to the actual demand at given times and geographic areas. This paper introduces the notion of energy partition, an association of powered-on and powered-off BSs to deliver network-level energy saving. It then elaborates how such concept is applied to perform energy re-configuration to flexibly re-act to load variations encouraging none or minimal extra energy consumption. A simulation-based study evaluates the performance of the proposed algorithms under different network topologies and traffic conditions, highlights the benefits and drawbacks, and provides recommendations for deployment scenarios.     

Proposal of a multi-agent model for the sustainable truck scheduling and containers grouping problem in a Road-Rail physical internet hub

Physical Internet (PI) was introduced as a global standardised and interconnected logistics system based on PI-nodes, PI-movers and PI-containers as a mean toward global logistics sustainability. One important issue regarding PI-nodes concerns the planning and scheduling of operations and the management of PI-containers, both in a deterministic and a perturbed environment. This research considers the Road-Rail PI-hub sustainable truck scheduling and PI-containers grouping problem. In our research we consider the weighted sum of the number of used wagons, the internal distance travelled by PI-containers from PI-docks to wagons as well as the trucks’ tardiness, which translate the search for sustainable logistics. In this paper, an effective and reactive multi-agent system based model (MAS) is developed for the resolution of the trucks scheduling and PI-containers grouping. To ensure the efficiency of the MAS and improve the quality of each of its solutions, three concurrent hybrid meta-heuristics are embedded within three parallel scheduling agents. Then, a mixed integer linear programming model (MILP) is proposed to evaluate the performance of the MAS. Finally, the MAS is also evaluated under internal perturbations. The obtained results show the ability of the MAS to provide alternative sustainable solutions by rescheduling trucks in case of disruptions.     

真空膜装置用于家庭废水回用

孔径为0．038μ并且总表面积为540m^2的平板膜生物反应器（MBR）在安卡拉METU大学间歇式运行了一年，用于处理来自宿舍和学院楼的家庭污水。MBR设备的第一阶段连续运行140天，水力保留时间在18-22h。这段时间内，污泥浓度从开始的2．4g／L增加到21g／L。当DO保持超过2．0mg／L时，该设备可以稳定地生产完全硝化的排出水。     

First-principles prediction of the structural and electronic properties of zinc blende GaNxAs1−x alloys

To investigate the structural and electronic properties of zinc blende GaN_xAs_1?x alloys, we performed full-potential linearized augmented plane wave (FP-LAPW) calculations based on density functional theory. We assessed GaN_xAs_1?x alloys for 0≤x≤1 using 16-atom special quasi-random structures. The generalized gradient approximation (GGA) of Wu and Cohen was used as the exchange correlation potential to calculate the structural and electronic properties of GaN_xAs_1?x. In addition, the alternative GGA proposed by Engel and Vosko and the modified Becke–Johnson potential were used for better reproduction of the band structure and electronic properties. The equilibrium lattice parameters and bulk modulus were calculated and analyzed for binary and ternary alloys. The lattice constants for GaN_xAs_1?x positively deviate from Vegard's law with an upward bowing parameter of ?0.4708 Å. All our materials are direct-bandgap semiconductors for which the valence band maximum is located at Γ_v and the conduction band minimum at Γ_c. We observed that the direct bandgap of GaN_xAs_1?x increases nonlinearly with x. To shed light on the bandgap trend for increasing nitrogen concentrations in GaN_xAs_1?x, we used the atoms-in-molecule formalism. Special attention was paid to the increase in charge transfer for the nitrogen atom and to ionicity as a function of increasing x concentration.     

Infectious disease: Connecting innate immunity to biocidal polymers

Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease.     

Physicochemical characterization and adsorptive properties of some Moroccan clay minerals extruded as lab-scale monoliths

Textural, structural and adsorptive properties of some Moroccan clays were investigated. The minerals were used as raw material for extrusion of honeycomb monoliths. Adsorption and desorption tests were performed with selected model pollutants such as volatile organic compounds (VOCs). The clays have been chosen, apart from their abundance and price, on the basis of successful extrusion as integral lab-scale honeycomb monoliths. The obtained monoliths have been subjected to measurements of the mechanical strength.     

Reactivity of surface isocyanate species with NO, O2 and NO+O2 in selective reduction of NOχ over Ag/Al2O3 and Al2O3 catalysts

Reactivity of surface isocyanate (NCO(a)) species with NO, O₂ and NO+O₂ in selective reduction of NOχ over Ag/Al₂O₃ and Al₂O₃ catalysts was studied by a pulse reaction technique and an in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The NCO(a) species on Ag/Al₂O₃ reacted with O₂ or NO+O₂ mixture gas to produce N₂ effectively above 200°C, while the reaction of NCO(a) with NO hardly produced N₂ even at 350°C. In the case of Al₂O₃ alone, less N₂ was detected in the reaction of NCO(a) with NO+O₂, indicating that silver plays an important role in the N₂ formation from NCO(a). These behaviors of the reactivity of NCO(a) species with reactant gases were in good agreement with the changes in NCO(a) bands shown by in situ DRIFT measurements. Based on these findings, the role of NCO(a) species in the selective reduction of NOχ on Ag/Al₂O₃ and Al₂O₃ catalysts is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Polymerization of methacryl and triethoxysilane functionalized stearate ester: Titanium dioxide composite films and their photocatalytic degradations

Stearoyl chloride was reacted with 3‐(acryloyloxy)‐2‐hydroxypropyl methacrylate (AHM). Then the resulting product (SAHM) was reacted with 3‐amino propyl ethoxysilane (APTES) by Michael addition on the acrylate. The product (SAHMA) is a specialized coupling agent containing an oleophilic 18 carbon alkyl chain, a radically polymerizable methacrylate and an alkoxysilane group capable of coupling to inorganic surfaces, analyzed by FT‐IR, NMR, and UV techniques. Photopolymerization and free radical homo and copolymerization of SAHMA with styrene were examined. SAHMA was coupled to powdered titanium dioxide (P25‐Degussa) and polymerized. TiO₂ filled materials were analyzed by SEM, UV and TGA techniques. Glass transiton temperatures (T_g) of the polymers were determined by differential scanning calorimeter (DSC). Interfacial compatibility between SAHMA and TiO₂ was demonstrated by FT‐IR spectroscopy. The photocatalytic degradation of the TiO₂‐SAHMA polymer films was also investigated under medium pressure mercury lamp illumination in air. SAHMA based film containing 2 wt % TiO₂ showed the highest degradation and the highest loss in weight. The weight of the polymer was reduced by 25% of its initial value after irradiation for 40 h. To examine the surface morphology of the irradiated polymer films, SEM analysis was carried out and cavities were detected around TiO₂ particles. The photocatalytic and thermomechanical properties of SAHMA and styrene (STY) based copolymers were also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007