Investigation of optical,dielectric, and multiferroic properties of (1 − x) Bi0.9La0.1FeO3–(x) BaTiO3 composites

Journal of Materials Science: Materials in Electronics - In the present work, we synthesized composites (1???x) Bi0.9La0.1FeO3-(x) BaTiO3 with x?=?0.05, 0.10, and 0.15...     

Comparative Analysis of Bio-Inspired Algorithms for Underwater Wireless Sensor Networks

Wireless Personal Communications - Mobile nodes in underwater wireless sensor networks are becoming very important as they not only enable flexible sensing areas but also entails the ability to...     

A multilayered photonic emitter for high-performance daytime radiative cooling

Microsystem Technologies - Daytime radiative cooling devices consisting of various materials are used to transmit and radiate heat energy from a target body outward through the atmosphere and into...     

Applications of Polycyclic Aromatic Hydrocarbons to Assess the Source and Thermal Maturity of the Crude Oils from the Lower Indus Basin,Pakistan

Abstract

A suite of six crude oils from Lower Indus Basin, Pakistan, were analyzed for geochemical characterization of source organic matter (OM) and thermal maturity. Distribution of polycyclic aromatic hydrocarbons (PAHs), alkylnaphthalenes, alkylphenanthrenes, alkyldibenzothiophenes, and aromatic biomarkers were reported from aromatic fractions of the crude oils. The aromatic hydrocarbons parameters revealed a higher thermal maturity of OM of source rock-generated Lower Indus Basin oils. Calculated vitrinite reflectance values from the methylphenanthrenes index 1 (MPI-1) and methyldibenzothiophene ratio (MDR) indicate that most of the oils reached a late oil generation window of thermal maturity. PAH distributions revealed the oils of two different origins are present in the Lower Indus Basin; two oil samples indicate aquatic source of OM and the aromatic biomarker distributions of retene, 1-MP, and 1,7-DMP indicate a significant contribution of land plant OM in the other four oils. This is the first study to report the distribution of aromatic hydrocarbons from Lower Indus Basin crude oils.     

Acid Activation of Kulantau Vermiculite

Adsorptive properties of laminated material with widening structural cell are determined by dispersion, which is depends on crystalline vermiculite grid structure. Created sorbents developed porous by acid activation desirable choice minerals with an expanding structural cell. Significant role in the formation of advanced sorbent porosity is the formation of thin layers of amorphous phase between partial destruction of the elements of the original structure of vermiculite.     

Heuristic optimization system for the determination of index positions on CNC magazines with the consideration of cutting tool duplications

This paper presents a meta-heuristic optimization system developed for the determination of optimal index positions of cutting tools on the tool magazines (automatic tool changer (ATC) or turret magazine, etc.) of CNC (computerized numerical control) machine tools. The selection of index positions is performed using a simulated annealing (SA) algorithm that takes the following as the input: (1) a list of cutting tools assigned to certain machining operations; (2) the number of copies of each cutting tool available in the workshop; (3) total number of index positions on the tool magazines; (4) the indexing time of a tool magazine of a CNC machine tool specified by manufacturer. Then, the SA algorithm determines index locations of cutting tools on the tool magazines. Dereli et al. and Dereli and Filiz previously studied the present problem by using genetic algorithms (GAs). However, the duplication of cutting tools was not taken into account in their works, although it can reduce the total tool-indexing time and therefore improve the productivity considerably. Nevertheless, the consideration of the ‘tool duplications’ makes the problem much harder to model and to solve. In this paper, a novel solution representation-scheme based on the SA, which enables easy manipulation during feasible neighbourhood solution generation, is proposed for the determination of the index positions of cutting tools on the CNC magazines with the consideration of ‘tool duplications’. Example problems are solved to present the implementation and merits of the proposed optimisation system. It is shown that it is possible to allocate the cutting tools in an efficient manner on the CNC magazines with the developed system.     

Efficient algorithm for cell formation with sequence data,machine replications and alternative process routings

Cell formation is an important problem in the design of a cellular manufacturing system. Despite a large number of papers on cell formation being published, only a handful incorporate operation sequence in intercell move calculations and consider alternative process routings, cell size, production volume and allocating units of identical machines into different cells. Modelling the above factors makes the cell formation problem complex but more realistic. The paper develops a model and solution methodology for a problem of cell formation to minimize the sum of costs of intercell moves, machine investment and machine operating costs considering all the factors mentioned above. An algorithm comprised of simulated annealing and local search heuristics has been developed to solve the model. A limited comparison of the proposed algorithm with an optimal solution generated by complete enumeration of small problems indicates that the algorithm produces a solution of excellent quality. Large problems with 100 parts and 50 machine types are efficiently solved using the algorithm.     

Electrical and optical properties of diketopyrrolopyrrole-based copolymer interfaces in thin film devices

Two donor-acceptor diketopyrrolopyrrole (DPP)-based copolymers (PDPP-BBT and TDPP-BBT) have been synthesized for their application in organic devices such as metal-insulator semiconductor (MIS) diodes and field-effect transistors (FETs). The semiconductor-dielectric interface was characterized by capacitance-voltage and conductance-voltage methods. These measurements yield an interface trap density of 4.2 × 10(12) eV?1 cm?2 in TDPP-BBT and 3.5 × 1012 eV?1 cm?2 in PDPP-BBT at the flat-band voltage. The FETs based on these spincoated DPP copolymers display p-channel behavior with hole mobilities of the order 10?3 cm2/(Vs). Light scattering studies from PDPP-BBT FETs show almost no change in the Raman spectrum after the devices are allowed to operate at a gate voltage, indicating that the FETs suffer minimal damage due to the metal-polymer contact or the application of an electric field. As a comparison Raman intensity profile from the channel-Au contact layer in pentacene FETs are presented, which show a distinct change before and after biasing.     

Surface-type humidity sensor based on cellulose-PEPC for telemetry systems

Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole(PEPC) blend thin films.A blend of 2wt%of each cellulose and PEPC in benzol was used for the deposition of humidity sensing films.Blend films were deposited on glass substrates with preliminary deposited surface-type gold electrodes.Films of different thicknesses of cellulose and PEPC composite were deposited by drop-casting technique.A change in electrical resistance and capacitance of the fabricated devices was observed by increasing the relative humidity in the range of 0-95%RH.It was observed that the capacitances of the sensors increase,while their resistances decrease with increasing the relative humidity.The sensors were connected to op-amp square wave oscillators.It was observed that with increasing the relative humidity,the oscillator’s frequencies were also increased in the range of 4.2-12.0 kHz for 65μm thick film sample,4.1-9.0 kHz for 88μm thick film sample,and 4.2-9.0 kHz for 210μm sample.Effects of film thickness on the oscillator’s frequency with respect to humidity were also investigated.This polymer humidity sensor controlled oscillator can be used for short-range and long-range remote systems at environmental monitoring and assessment of the humidity level.     

On the reliability of ad hoc routing protocols for loss-and-delay sensitive applications

In this paper, we analyze the packet delivery reliability of ad hoc routing protocols for loss-and-delay sensitive applications. Since a typical flooding-based route discovery used in ad hoc routing protocols – DSR for instance – can only discover node-disjoint paths. In this context, we first show that the reliability function of such a multipath system is concave with respect to the total number of paths. Therefore, maximum steady-state reliability may be attained by routing each packet through a small set of node-disjoint paths. Subsequently, we prove that a partially-disjoint path is more reliable than a node-disjoint path. Hence, high reliability and significant energy savings may be achieved by routing a packet through fewer partially-disjoint paths. Based on these findings, we suggest modifications to flooding-based route discovery procedure to discover partially-disjoint paths. We complement our theoretical outcomes through extensive simulations. Finally, we analyze the reliability of beacon-based routing protocols and derive an upper bound on the number of hops at which a beacon should be placed to satisfy a given packet reliability constraint.