A Review on Precision Agriculture Using Wireless Sensor Networks Incorporating Energy Forecast Techniques

Wireless Personal Communications - Wireless sensor networks (WSNs) are prominently used for environment monitoring, however, energy constraints limit their applications. So, the energy consumption...     

Granularity-based workflow scheduling algorithm for cloud computing

The workflow scheduling problem has drawn a lot of attention in the research community. This paper presents a workflow scheduling algorithm, called granularity score scheduling (GSS), which is based on the granularity of the tasks in a given workflow. The main objectives of GSS are to minimize the makespan and maximize the average virtual machine utilization. The algorithm consists of three phases, namely B-level calculation, score adjustment and task ranking and scheduling. We simulate the proposed algorithm using various benchmark scientific workflow applications, i.e., Cybershake, Epigenomic, Inspiral and Montage. The simulation results are compared with two well-known existing workflow scheduling algorithms, namely heterogeneous earliest finish time and performance effective task scheduling, which are also applied in cloud computing environment. Based on the simulation results, the proposed algorithm remarkably demonstrates its performance in terms of makespan and average virtual machine utilization.     

Robust Silica Aerogel Microspheres from Rice Husk Ash to Enhance the Dissolution Rate of Poorly Water-Soluble Drugs

The present paper demonstrates the capability of specially prepared robust silica aerogel microspheres (RSAMs) to enhance the dissolution rate of poorly water-soluble drugs. A sol-gel/mineral oil emulsion method has been developed for RSAMs from rice husk ash (RHA), a biogenic source. The particles were characterized for their Brunauer–Emmett–Teller (BET) specific surface area, Barrett, Joyner and Halenda (BJH) pore volume and pore diameter, and morphology by optical microscopy and scanning electron microscopy (SEM). The dissolution rate of ibuprofen, a poorly water-soluble drug, was investigated by adsorbing it onto RSAMs upon dissolving it in supercritical carbon dioxide (scCO₂) at 150?bar and 40°C. This resulted in a loading of ～0.13?g ibuprofen/g loaded RSAMs in 24?h. X-ray diffraction analysis was used to characterize the nature of the adsorbed ibuprofen onto RSAMs. It was observed that the loaded drug on the aerogels is in amorphous form. An in vitro drug-release kinetic studies confirmed a significant enhancement in the dissolution rate, namely ～100% of the loaded ibuprofen released as compared to that of ～11% of crystalline ibuprofen in 15?min.     

Diffusion coefficients of aqueous cesium fluoride at 40°C

Diaphragm cell technique has been employed to determine diffusion coefficient for cesium fluoride at 40°C in the concentration range varying from 0.01 to 0.1 M. The data were analysed in the light of the theory of Onsager and Fuoss (O-F), J. chem. Phys.2, 599 (1932)[20]. The results indicate that the O-F theory is inadequate to explain the behaviour of this salt at 45°C. The results are also discussed with other 1:1 type salts of cesium.     

Extraction of selected rare earth elements from anthracite acid mine drainage using supercritical CO_2 via coagulation and complexation

Rare earth elements(REEs) are valuable raw materials which are in great demand in modern high technology industries.Developing methods to produce/recover REEs from waste is significant to the national security of any developed country.This study was focused on investigating the use of supercritical CO2(sCO_2) to extract REEs from anthracite acid mine drainage(AMD).Four different mine drainage water source locations at Blaschak Coal Corp.in Pennsylvania,USA were selected for sample collection.An extraction process was developed and demonstrated for two of those water sources containing the highest concentration of REEs.A method involving metal ion coagulation,their dissolution from the sludge into a concentrated aqueous HNO_3 solution,complexation with organic ligands and sCO_2 extraction was developed to recover REEs from AMD.Specifically,sodium aluminate(NaAlO_2) was used as the coagulant to concentrate REEs from the AMD into a solid precipitate.Consequently,over 99%of the REEs in AMD is concentrated in the remaining sludge.During the coagulation process,the effects of pH and NaAlO_2 concentration on REE precipitation were investigated.Fuming nitric acid(HNO_3) was used to digest the pre-concentrated sludge and tributyl phosphate(TBP) was used to form REE/TBP/HNO_3,a non-polar complex with selected REEs,specifically,cerium(Ce),lanthanum(La) and neodymium(Nd).HNO_3 concentration and organic/aqueous phase ratio were considered as the variables to improve complexation efficiency.Dynamic extraction experiments using sCO_2 and REE/TBP/HNO_3 solutions were then conducted at optimal conditions of 60℃ and 20 MPa.The overall REE extraction efficiencies are found to increase with the atomic number of the REE.As a result,the average overall REE extraction efficiencies of 41.8%,40.1% and 58.2% for Ce,La and Nd,respectively,are obtained.The potential improvements in the overall extraction efficiency are also discussed.     

Hysteresis studies in Clarke solder-blob junctions

A study of hysteresis in Clarke solder-blob junctions has been carried out in the temperature range 4.2–1.2 K. The temperature dependence of the critical current, the variation of the constant-temperature critical current with sequential sweep cycles, and the effects of an external field are studied. All the experimental results are explained as due to a net trapping of magnetic flux in the junction loop whenever a hysteretic curve is traced. The origin of the flux can be traced to the inductance of the superconducting loop and the electrical or geometrical asymmetry.     

Effect of excipient and processing variables on adhesive properties and release profile of pentoxifylline from mucoadhesive tablets

The bioavailability and onset of action of drugs with high first-pass metabolism can be significantly improved by administration via the sublingual route. The objective of this study was to evaluate the effect of polymer type and tablet compaction parameters on the adhesive properties and drug release profile from mucoadhesive sublingual tablet formulations. Pentoxifylline was selected as the model drug because it has poor oral bioavailability due to extensive first-pass metabolism. Two polymers known to possess mucoadhesive properties, carbomer and hydroxypropyl methyl cellulose (HPMC), were used to prepare the formulations. Tablets were prepared by using direct compression technique and evaluated for in vitro dissolution, drug-excipient interactions, and adhesive properties. In general, there was a decrease in the rate of drug release with an increase in the concentration of polymers. No drug-excipient interactions were evident from differential scanning calorimetry or high-performance liquid chromatography analysis. For the formulations containing HPMC, the force of mucoadhesion increased with an increase in the concentration of polymer; however, for carbomer formulations, no such correlation was observed. Force of mucoadhesion decreased as a function of hydration time in both of the polymers.     

Dynamic behaviour of protective covers in machine tools

The durability of protective covers in high dynamic machine tools is no longer acceptable. Due to high velocities and acceleration, the structural components of the bellow, the crossbar mechanism for example, do not withstand the occurring forces. The following article analyses the forces which affect a protective cover occurring due to feed motion of the axis. The requirements of protective covers are defined in order to derive the cycles for the dynamic tests. The measured variables recorded during the trials are analyzed and associated to the structural components of the bellow. This research is supported by the Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e. V.     

LED背光照明系统的设计方案选项利弊分析

LED正成为中小型彩色显示器背光照明应用的主流器件。LED的选择是决定显示子系统设计最佳性价比的关键因素。此外，LED驱动IC，尤其是最新的产品，能与较低成本的LED协同工作，透过多种方法提升现有LED的性能。除亮度控制外，这些驱动IC还能实现精确的亮度匹配，或允许使用一系列具备不同VF特性的LED。