Neural network-based model for prediction of permanent deformation of unbound granular materials

Several available mechanistic-empirical pavement design methods fail to include predictive model for permanent deformation (PD) of unbound granular materials (UGMs), which make these methods more conservative. In addition, there are limited regression models capable of predicting the PD under multi-stress levels, and these models have regression limitations and generally fail to cover the complexity of UGM behaviour. Recent researches are focused on using new methods of computational intelligence systems to address the problems, such as artificial neural network (ANN). In this context, we aim to develop an artificial neural model to predict the PD of UGMs exposed to repeated loads. Extensive repeated load triaxial tests (RLTTs) were conducted on base and subbase materials locally available in Victoria, Australia to investigate the PD properties of the tested materials and to prepare the database of the neural networks. Specimens were prepared over different moisture contents and gradations to cover a wide testing matrix. The ANN model consists of one input layer with five neurons, one hidden layer with twelve neurons, and one output layer with one neuron. The five inputs were the number of load cycles, deviatoric stress, moisture content, coefficient of uniformity, and coefficient of curvature. The sensitivity analysis showed that the most important indicator that impacts PD is the number of load cycles with influence factor of 41%. It shows that the ANN method is rapid and efficient to predict the PD, which could be implemented in the Austroads pavement design method.     

Flexible polymer‐multiwall carbon nanotubes composite developed by in situ polymerization technique

Mechanically robust and flexible polymer‐multiwall carbon nanotubes (MWCNT) composites are developed by in situ polymerization technique, where MWCNT are embedded in nontoxic, bio‐compatible acryl amide‐based polymer matrix. The addition of glycerol in the composite imparts required flexibility and a further addition of poly (3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) shows significant improvements in tensile modulus, strength, and toughness compared to the polymer matrix. The composite is characterized by Scanning electron microscopy, Raman spectroscopy Attenuated total reflectance Fourier Transform infrared spectroscopy. At optimized conditions; the composite forms a heterojunction diode with n‐Silicon having an electronic rectification ratio of 2.11 at ±1 V and a further addition of conducting polymer PEDOT: PSS in the composite enhances the electronic current rectification to 13.63 at ±1 V, with the turn on voltage of the device at 0.35 V. POLYM. COMPOS., 37:2860–2870, 2016. © 2015 Society of Plastics Engineers     

Effects of sparger height and orifice orientation on solids dispersion in a slurry bubble column

The effects of gas distributor height and the orientation of its orifices are investigated on solids dispersion and gas holdup profiles in a three-phase slurry bubble column. The height of the distributor was varied to cover locations from near column bottom to above the settled solids bed height. The orifice orientations were changed from upward facing to downwards facing directions. The measurements were conducted in a Plexiglas column of 0.15 m ID and 2.5 m height. The gas phase was oil-free compressed air while tap water was used as liquid phase. Glass beads with an average particle diameter of 35 μm and density of 2450 kg/m³ constituted the solid phase. The settled bed height was about 0.4 m which provided an average slurry concentration of about 15% (v/v) when all solids were dispersed. Both axial and column average phase holdups were measured. Effects of sparger location, gas jets formation and liquid circulation patterns on gas holdups and solids dispersion are analyzed. Empirical correlations are developed to relate sparger location to solids dispersion as a function of gas velocity. Optimum sparger height and orifice orientation is proposed based on the measurement of this study.     

MATE1 Deficiency Exacerbates Dofetilide-Induced Proarrhythmia

Dofetilide is a rapid delayed rectifier potassium current inhibitor widely used to prevent the recurrence of atrial fibrillation and flutter. The clinical use of this drug is associated with increases in QTc interval, which predispose patients to ventricular cardiac arrhythmias. The mechanisms involved in the disposition of dofetilide, including its movement in and out of cardiomyocytes, remain unknown. Using a xenobiotic transporter screen, we identified MATE1 (SLC47A1) as a transporter of dofetilide and found that genetic knockout or pharmacological inhibition of MATE1 in mice was associated with enhanced retention of dofetilide in cardiomyocytes and increased QTc prolongation. The urinary excretion of dofetilide was also dependent on the MATE1 genotype, and we found that this transport mechanism provides a mechanistic basis for previously recorded drug-drug interactions of dofetilide with various contraindicated drugs, including bictegravir, cimetidine, ketoconazole, and verapamil. The translational significance of these observations was examined with a physiologically-based pharmacokinetic model that adequately predicted the drug-drug interaction liabilities in humans. These findings support the thesis that MATE1 serves a conserved cardioprotective role by restricting excessive cellular accumulation and warrant caution against the concurrent administration of potent MATE1 inhibitors and cardiotoxic substrates with a narrow therapeutic window.     

A key pre-distribution scheme for wireless sensor networks: merging blocks in combinatorial design

In this paper, combinatorial design followed by randomized merging strategy is applied to key pre-distribution in sensor nodes. A transversal design is used to construct a (v, b, r, k) configuration and then randomly selected blocks are merged to form the sensor nodes. We present detailed mathematical analysis of the number of nodes, number of keys per node and the probability that a link gets affected if certain number of nodes are compromised. The technique is tunable to user requirements and it also compares favourably with state of the art design strategies. An important feature of our design is the presence of more number of common keys between any two nodes. Further, we study the situation when properly chosen blocks are merged to form sensor nodes such that the number of intra-node common key is minimized. We present a basic heuristic for this approach and show that it provides slight improvement in terms of certain parameters than our basic random merging strategy. This paper is an extended and revised version of the paper presented in 8th Information Security Conference, ISC'05, pp. 89–103, Lecture Notes in Computer Science, vol. 3650, Springer Verlag. Dibyendu Chakrabarti received his Master of Technology in Computer Science in the year 1998 from the Indian Statistical Institute, Kolkata. Currently he is pursuing his Ph.D. from the Indian Statistical Institute, Kolkata. He is working in the area of Sensor Networks. Subhamoy Maitra received his Bachelor of Electronics and Telecommunication Engineering degree in the year 1992 from Jadavpur University, Kolkata and Master of Technology in Computer Science in the year 1996 from the Indian Statistical Institute, Kolkata. He has completed Ph.D. from the Indian Statistical Institute in 2001. Currently he is an Associate Professor at the Indian Statistical Institute. His research interest is in Cryptology, Digital Watermarking, and Sensor Networks. Prof. Bimal Roy obtained his Master's degree from the Indian Statistical Institute, Calcutta, India in 1979 and Ph.D. from University of Waterloo, Canada in 1982. He is currently a professor at the Indian Statistical Institute, Kolkata. His research area includes Cryptography, Security, Combinatorics etc. His special topics of interest are: Sensor Networks, Visual Cryptography, Hash Functions and Stream Ciphers.     

考虑浆体黏度的泥石流流速计算方法

泥石流浆体黏度通过影响泥石流内、外部的阻力特征影响泥石流的糙率系数,泥石流糙率系数与浆体黏度之间的关系还没有基于观测数据的定量表述。通过对云南东川蒋家沟泥石流观测资料的分析,研究泥石流糙率系数与浆体黏度之间的关系,并通过回归分析得到考虑浆体黏度的泥石流糙率系数计算公式,最后基于此构建了考虑浆体黏度的泥石流流速计算公式。结果表明,随着泥石流浆体黏度的增加,泥石流糙率系数逐渐增加,浆体黏度在宏观上表现为增阻作用,考虑浆体黏度的泥石流流速计算公式改进了现有公式在计算浆体黏度较高的泥石流流速中的不足。研究结果可为进一步研究浆体黏度对泥石流运动阻力的影响提供参考,也为工程实践中的流速计算和增阻消能设计提供新的思路。     

Blood flow in a stenotic artery with temperature-dependent viscosity

We investigate the effects of temperature-dependent viscosity variations on the flow and heat transfer characteristics in an artery in the presence of stenosis. The dimensionless governing equations have been solved using the implicit finite difference method. The local skin friction coefficient and the local Nusselt number at the lower and upper walls are found to be stronger with the increase of stenosis. With the change of position of the upper stenosis, the skin friction and the Nusselt number at the lower plate demonstrate distinct characteristics. A remarkable result is that when the viscosity variation parameter is increased, the vortices following the stenosis become smaller in size. Moreover, the size of vortices increases with the increase of stenosis, whereas it is found to decrease owing to the change of position of the upper stenosis.     

Optimum Abstraction of Groundwater for Sustaining Groundwater Level and Reducing Irrigation Cost

Adaptation to increasing irrigation cost due to declination of groundwater level is a major challenge in groundwater dependent irrigated region. The objective of this study is to estimate the optimum abstraction of groundwater for irrigation for sustainable management of groundwater resources in Northwest Bangladesh. A data-driven model using a support vector machine (SVM) has been developed to estimate the optimum abstraction of groundwater for irrigation and a multiple-linear regression (MLR)-based model has been developed to estimate the reduction of the irrigation cost due to the elevation of the groundwater level. The application of the SVM model revealed that the groundwater level in the area can be kept within the suction lift of a shallow tube-well by reducing pre-monsoon groundwater-dependent irrigated agriculture by 40%. Adaptive measures, such as reducing the overuse of water for irrigation and rescheduling harvesting, can keep the minimum level of groundwater within the reach of shallow tube-wells by reducing only 10% of groundwater-based irrigated agriculture. The elevation of the groundwater level through those adaptive measures can reduce the irrigation cost by 2.07 × 10³ Bangladesh Taka (BDT) per hectare in Northwest Bangladesh, where the crop production cost is increasing due to the decline of the groundwater level. It is expected that the study would help in policy planning for the sustainable management of groundwater resources in the region.     

Electrophoretic deposition of doped ceria in anti-gravity set-up

An innovative anti-gravity set-up has been designed and fabricated to consolidate doped ceria powder by electrophoretic deposition. In this set-up, the charged ceramic powders dispersed in non-aqueous suspension moved upward in opposite direction to gravity under the influence of an external applied field and were consequently deposited on the lower face of upper electrode placed horizontally parallel above the counter electrode. Electrophoretic deposition using this innovative technique was found more superior to the conventional electrophoretic deposition using vertically arranged electrodes where a very broad particle size range was used. The deposit thus obtained predominantly contained finer particles which can move relatively easily against gravity. It enabled formation of homogeneous compact films. This paper presents the results of detailed investigation on the effect of different process parameters such as concentration of particles, duration, addition of charge modifier etc. on forming a deposit. A comparison of deposition yield in anti-gravity set-up vis-à-vis conventional set-up is also presented.     

Dehydrated foods: Are they microbiologically safe?

ABSTRACT

Dried foods are low water activity foods with water activity ranging from 0.03 to 0.7. They are commonly misconstrued to be inherently safe from food borne pathogenic bacteria. However, there are many reported cases where many food borne illnesses were caused by the consumption of dried foods contaminated with Salmonella spp., Cronobacter spp., Staphylococcus spp. and E. coli. In this work, we have systematically reviewed the literature dealing with the effect of drying/dehydration on the survival of pathogenic microorganisms with special focus on Salmonella spp. We have also reviewed and synthesized the literature dealing with the effect of drying process on microorganisms in dried vegetables, meat, fish, spices, mushroom and powdered foods. This review concludes that dried foods are not inherently safe microbiologically and required other hurdles to achieve microbial safety.