A multilayer thickness relationship applicable to pore size analysis of silica gel

A single multilayer curve was arrived at for the adsorption of nitrogen on silica gel. An empirical equation, fitted to the curve, proved to be suitable in the pore size analysis of 26 samples of silica gels; specific surface areas from 178 to 814 m²/g, mean pore radii of 12.6 up to 74.4 Å, and total pore volumes of 0.5126 to 0.8613 ml/g. Cumulative surface areas were evaluated by the procedures of BJH, Cranston and Inkley, and Roberts; the values obtained were generally in agreement with specific surface areas obtained by the BET equation, S_BET, within ± 5%. The empirical equation is completely independent of the structural characteristics of the material. Comparison was made with data obtained by the use of the method of Mingle and Smith, for evaluating multilayer thickness, and which depends on both mean pore radius, and BET-C value, for each single solid. Good concordance appears between the cumulative surface areas, as well as the pore size distributions, calculated by employing either this latter t-estimate or the empirical equation.     

Design and analysis of resonant cavity-enhanced quantum ring inter-subband photodetector with resonant tunneling barriers for terahertz detection

The effect of resonant cavity structure on the performance operation of In As/Ga As quantum ring intersubband photodetector is studied for detection of terahertz radiations range.In order to confinement of optical field w ithin active region and consequently enhancement in responsivity of device,tw o periods of Al2O3/Ga As distributed bragg reflectors are used as bottom dielectric mirror and a thin layer of Au material as top mirror of device.For further improvement in detectivity,Al0.3Ga0.7As/In0.3Ga0.7As resonant tunneling barriers are included in absorption layers to reduce dark current of device.Proposed photodetector show s a peak responsivity of about 0.4(A/W)and quantum efficiency of 1.2%at the w avelength of 80μm(3.75 THz).Furthermore,specific detectivity(D*)of device is calculated and results are compared to conventional quantum ring inter-subband photodetector.Results predict a D*of~1011(cm.Hz1/2/W)for device at T=80 K and V=0.4 V w hich is tw o orders of magnitude higher than that of conventional QRIPs.     

Photografting Coating: An Innovative Approach to “Non-Migratory” Active Packaging

The increasing trend of sustainability (single-use packaging), safety (fresh consumption), and convenience (processing and application) in packaging science has created a high demand for packaging materials with advanced functions. Thus, the challenges involved with conventional active packaging, for example, migration, low efficiency, upscaling difficulty, safety, and regulations should be addressed through an industrial scalable method, such as photografting coating. Photografting coating, which involves a strong surface covalent linkage, can be employed for preparing novel “non-migratory” active packaging systems with strong antimicrobial and self-cleaning, antifouling and self-defensive, metal chelating as antioxidant, free-radical scavenging as antioxidant, biocatalytic, and easy printing properties. Herein, profound insights into the technique of photografting coating are provided, with a focus on its application potential in non-migratory active packaging. The scientific explanation for the photografting coating technique and its application feasibility are illustrated to introduce its potential to confer new functions onto packaging materials. Furthermore, the recent progress, application functions, process, and safety challenges, as well as future directions of photografting coating in the preparation of non-migratory active packaging systems are explored in detail.     

An entropy-based self-adaptive simulated annealing

Engineering with Computers - Simulated annealing (SA) algorithms are capable of solving discrete and continuous problems. However, they are less efficient than other algorithms in solving applied...     

Expert support systems design issues

Expert support systems (ESSs) promise valuable support to decision-makers in business settings where a number of complex and interacting decisions must be accommodated. Even though the proliferation of ESSs in business has been limited, the issues involved in designing such systems need to be addressed so that development resources are well utilized and the end product is successful. This paper addresses the following questions: What are the factors that affect the successful design of an ESS? And how do these factors affect the design process? These factors are identified by considering factors that are relevant to MIS development and how they relate to the new technology of expert systems. A prototype ESS is used to illustrate the issues addressed in this paper.     

A recursive genetic framework for evolutionary decision-making in problems with high dynamism

Communication and coordination are the main cores for reaching a constructive agreement among multi-agent systems (MASs). Dividing the overall performance of MAS to individual agents may lead to group learning as opposed to individual learning, which is one of the weak points of MASs. This paper proposes a recursive genetic framework for solving problems with high dynamism. In this framework, a combination of genetic algorithm and multi-agent capabilities is utilised to accelerate team learning and accurate credit assignment. The argumentation feature is used to accomplish agent learning and the negotiation features of MASs are used to achieve a credit assignment. The proposed framework is quite general and its recursive hierarchical structure could be extended. We have dedicated one special controlling module for increasing convergence time. Due to the complexity of blackjack, we have applied it as a possible test bed to evaluate the system’s performance. The learning rate of agents is measured as well as their credit assignment. The analysis of the obtained results led us to believe that our robust framework with the proposed negotiation operator is a promising methodology to solve similar problems in other areas with high dynamism.