A Simple Closed form Approximation of Average Channel Capacity for Weakly Turbulent Optical Wireless Links

Wireless Personal Communications - Performance of optical wireless link is degraded by the presence of atmospheric turbulence induced fading. In this paper, a simple tight closed form expression...     

Evaluation of effect of blast design parameters on flyrock using artificial neural networks

Flyrock, the propelled rock fragments beyond a specific limit, can be considered as one of the most crucial and hazardous events in the open pit blasting operations. Involvement of various effective parameters has made the problem so complicated, and the available empirical methods are not proficient to predict the flyrock. To achieve more accurate results, employment of new approaches, such as artificial neural network (ANN) can be very helpful. In this paper, an attempt has been made to apply the ANN method to predict the flyrock in the blasting operations of Sungun copper mine, Iran. Number of ANN models was tried using various permutation and combinations, and it was observed that a model trained with back-propagation algorithm having 9-5-2-1 architecture is the best optimum. Flyrock were also computed from various available empirical models suggested by Lundborg. Statistical modeling has also been done to compare the prediction capability of ANN over other methods. Comparison of the results showed absolute superiority of the ANN modeling over the empirical as well as statistical models. Sensitivity analysis was also performed to identify the most influential inputs on the output results. It was observed that powder factor, hole diameter, stemming and charge per delay are the most effective parameters on the flyrock.     

Optimization of operating conditions in a single‐zone drier for two‐layer polymer coatings

In industrial dryers, hot air is blown over wet coatings either from top or from both top and bottom sides to remove the solvent. Drying of multilayer coatings is a complicated process that involves simultaneous heat and mass transfer, transport, and thermodynamic behavior of polymer solutions. Airflow and its temperature are important operating conditions in a dryer. We report optimization of the operating conditions to minimize residual solvent without inducing blisters for two‐layer coatings using mathematical modeling. Our results reveal that optimal air flow on the bottom side of the coating is always greater than or equal to that on its top side—an agreement with the common notion of “backside drying.” Furthermore, the effect of coating thickness, residence time, individual layer thickness, initial solvent concentration, and reversal of the two layers on the optimal conditions is discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Correlation between Phenotype and Genotype in CTNNB1 Syndrome: A Systematic Review of the Literature

The CTNNB1 Syndrome is a rare neurodevelopmental disorder associated with developmental delay, intellectual disability, and delayed or absent speech. The aim of the present study is to systematically review the available data on the prevalence of clinical manifestations and to evaluate the correlation between phenotype and genotype in published cases of patients with CTNNB1 Syndrome. Studies were identified by systematic searches of four major databases. Information was collected on patients’ genetic mutations, prenatal and neonatal problems, head circumference, muscle tone, EEG and MRI results, dysmorphic features, eye abnormalities, early development, language and comprehension, behavioral characteristics, and additional clinical problems. In addition, the mutations were classified into five groups according to the severity of symptoms. The study showed wide genotypic and phenotypic variability in patients with CTNNB1 Syndrome. The most common moderate-severe phenotype manifested in facial dysmorphisms, microcephaly, various motor disabilities, language and cognitive impairments, and behavioral abnormalities (e.g., autistic-like or aggressive behavior). Nonsense and missense mutations occurring in exons 14 and 15 were classified in the normal clinical outcome category/group because they had presented an otherwise normal phenotype, except for eye abnormalities. A milder phenotype was also observed with missense and nonsense mutations in exon 13. The autosomal dominant CTNNB1 Syndrome encompasses a wide spectrum of clinical features, ranging from normal to severe. While mutations cannot be more generally categorized by location, it is generally observed that the C-terminal protein region (exons 13, 14, 15) correlates with a milder phenotype.     

Implementation of slow wave characteristics in a microstrip antenna and its implementation with substrate integrated waveguide

In this article, a planar slow wave long‐wire‐antenna (LWA) is proposed for RF and microwave applications. Mathematical design equations of transformation of cylindrical LWA into planar microstrip antenna are presented. Slow wave effect produced by LWA is demonstrated in terms of group delay in a square slot aperture antenna and the same is compared with the proposed LWA embedded with square slot in the ground plane. Furthermore, substrate integrated waveguide is embedded with the proposed structure which further enhance the antenna gain and group delay. Group delay of about 2 ns is enhanced to the value of 26.7 ns after the integration of substrate integrated waveguide with LWA. Finite element method is used to investigate the design through Ansoft HFSS simulator, which is further validated by measured results of fabricated prototype.     

Application of an expert system to predict thermal conductivity of rocks

In this paper, an attempt has been made to predict the thermal conductivity (TC) of rocks by incorporating uniaxial compressive strength, density, porosity, and P-wave velocity using support vector machine (SVM). Training of the SVM network was carried out using 102 experimental data sets of various rocks, whereas 25 new data sets were used for the testing of the TC by SVM model. Multivariate regression analysis (MVRA) has also been carried out with same data sets that were used for the training of SVM model. SVM and MVRA results were compared based on coefficient of determination (CoD) and mean absolute error (MAE) between experimental and predicted values of TC. It was found that CoD between measured and predicted values of TC by SVM and MVRA was 0.994 and 0.918, respectively, whereas MAE was 0.0453 and 0.2085 for SVM and MVRA, respectively.     

A review on existing opencast coal mining methods within Australia

Currently almost 65 % of the coal in Australia is being produced by opencast mining methods. Mining equipments such as draglines, dredgers or bucket wheel excavators, trucks and shovels, and dozers are the main equipments employed for overburden removal and coal extraction. The choice of equipment for a particular mine depends on geological, geotechnical and economic factors and other site issues. This paper provides a general review of the main equipments used in Australia, including examples of some existing mines and the reasons for their choice of equipment. In addition, the paper discusses major geo-mechanical issues encountered and how these may influence the selection of appropriate equipments used in open cut mining operations.     

Double-diffusive mixed convection in a vertical pipe: A thermal non-equilibrium approach

In this article, double-diffusive mixed convection in a vertical pipe under local thermal non-equilibrium state has been investigated. The non-Darcy Brinkman–Forchheimer-extended model has been used and solved numerically by spectral collocation method. Special attention is given to understand the effect of buoyancy ratio (N) and thermal non-equilibrium parameters: inter phase heat transfer coefficient (H) as well as porosity scaled thermal conductivity ratio (γ) on the flow profiles as well as on rates of heat and solute transfer. Judged from the influence of buoyancy ratio on velocity profile, when both the buoyancy forces: thermal as well as solutal are in favor of each other and for given any value of H considered in this study, it has been found that for N equal to 10 as well as 100, the basic velocity profile shows back flow for small subdomain of the domain of the flow. When two buoyancy forces are opposing to each other (Ra_T = ?1000), velocity profile possesses a kind of distortion, in which the number of zeroes increases on increasing N. Corresponding variation of heat transfer rate in the (N,  Nu_f)-plane shows a sinusoidal pattern. The flow separation on the flow profile dies out on increasing H for N = 0. It has been also found that for each N, when N < 0.7, there exists a minimum value of H such that the velocity profile becomes free from flow separation. Influence of H on the profiles of solid temperature as well as solute, in both situations are similar. Overall, the impact of LTNE parameters, specially γ, on heat transfer rate of double-diffusive convection is not straight forward.     

Feasibility of Amending Slurry Walls with Zero-Valent Iron

Rapid degradation of aqueous trichloroethylene (TCE) was observed in batch experiments conducted with soil∕bentonite slurry wall materials amended with the addition of zero-valent iron. The first-order TCE decay constants for soil∕bentonite∕iron mixtures, when normalized to the available iron surface area, were approximately 1–2 orders of magnitude higher than observed in batch experiments with pure iron systems. Permeability tests indicated an increase in SB hydraulic conductivity roughly proportional to the amount of iron added. Based on the observed reaction rates and the assumption of sustained long-term performance, significantly less than one percent added iron would be required to reduce the diffusive flux of TCE across an installed slurry wall by over 10 orders of magnitude. However, the release of hydrogen gas was noted as a potential problem for low permeability systems containing zero-valent iron.