Soil Chemical Analysis

A large body of work has been reported in the last 5 years on the development of lead-free piezoceramics in the quest to replace lead–zirconate–titanate (PZT) as the main material for electromechanical devices such as actuators, sensors, and transducers. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented. Suitable chemical elements are selected first on the basis of cost and toxicity as well as ionic polarizability. Different crystal structures with these elements are then considered based on simple concepts, and a variety of phase diagrams are described with attractive morphotropic phase boundaries, yielding good piezoelectric properties. Finally, lessons from density functional theory are reviewed and used to adjust our understanding based on the simpler concepts. Equipped with these guidelines ranging from atom to phase diagram, the current development stage in lead-free piezoceramics is then critically assessed.

Perspective on the Development of Lead-free Piezoceramics

Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

Single-phased ferroelectromagnet BiFeO3 ceramics with high resistivity were synthesized by a rapid liquid phase sintering technique. Saturated ferroelectric hysteresis loops were observed at room temperature in the ceramics sintered at 880 °C for 450 s. The spontaneous polarization, remnant polarization, and the coercive field are 8.9 μC/cm2, 4.0 μC/cm2, and 39 kV/cm, respectively, under an applied field of 100 kV/cm. It is proposed that the formation of Fe2+ and an oxygen deficiency leading to the higher leakage can be greatly suppressed by the very high heating rate, short sintering period, and liquid phase sintering technique. The latter was also found effective in increasing the density of the ceramics. The sintering technique developed in this work is expected to be useful in synthesizing other ceramics from multivalent or volatile starting materials.

Room-temperature saturated ferroelectric polarization in BiFeO3 ceramics synthesized by rapid liquid phase sintering

Novel gas sensors with high sensing properties, simultaneously operating at room temperature are considerably more attractive owing to their low power consumption, high security and long-term stability. Till date, zinc oxide (ZnO) as semiconducting metal oxide is considered as the promising resistive-type gas sensing material, but elevated operating temperature becomes the bottleneck of its extensive applications in the field of real-time gas monitoring, especially in flammable and explosive gas atmosphere. In this respect, worldwide efforts have been devoted to reducing the operating temperature by means of multiple methods In this communication, room-temperature gas sensing properties of ZnO based gas sensors are comprehensively reviewed. Much more attention is particularly paid to the effective strategies that create room-temperature gas sensing of ZnO based gas sensors, mainly including surface modification, additive doping and light activation. Finally, some perspectives for future investigation on room-temperature gas-sensing materials are discussed as well.

Room-temperature gas sensing of ZnO-based gas sensor: A review

Glass formation and topology in relation to free volume, glass transition and band structure in Ge-Se-Sb chalcogenide system

Fabrication and modeling of laser ablated NiO nanoparticles decorated SnO2 based formaldehyde sensor

Gallium oxide and in particular its thermodynamically stable \b{eta}-Ga2O3 phase is within the most exciting materials in research and technology nowadays due to its unique properties, such as an ultra-wide band gap and a very high breakdown electric field, finding a number of applications in electronics and optoelectronics. Ion implantation is a traditional technological method used in these fields, and its well-known advantages can contribute greatly to the rapid development of physics and technology of Ga2O3-based materials and devices. Here, the current status of ion beam implantation in \b{eta}-Ga2O3 is reviewed. The main attention is paid to the results of experimental study of damage under ion irradiation and the properties of Ga2O3 layers doped by ion implantation. The results of ab initio theoretical calculations of the impurities and defects parameters are briefly presented, and the physical principles of a number of analytical methods used to study implanted gallium oxide layers are highlighted. The use of ion implantation in the development of such Ga2O3-based devices as metal oxide field effect transistors, Schottky barrier diodes, and solar-blind UV detectors, is described together with systematical analysis of the achieved values of their characteristics. Finally, the most important challenges to be overcome in this field of science and technology are discussed.

Ion implantation in \b{eta}-Ga2O3: physics and technology

Major problems with frozen semen doses (FSD) production from crossbred dairy bulls are high disposal rates due to unsatisfactory breeding soundness, sub-fertility, poor semen quality, and freezability. The study aims to evaluate, within the same genetic background of bulls, the identification of important non-genetic factors that could significantly influence semen characteristics and breeding ability. Bulls' category (FSD producer vs. no FSD producer) had significantly affected sperm and semen traits. Age significantly affected all semen attributes studied, and quality increased up to five years of age in FSD bulls, in contrast, only two years in Non-FSD bulls. The semen quality index (SQI) of Non-FSD bulls remained inferior lifelong, and five years old Non-FSD bulls SQI was even lesser than that of two years old FSD bulls. Seasons significantly influenced ejaculate characteristics, sperm productivity, and FSD production. Semen quality, sperm output, and FSD production were the highest during summer and lowest in rainy seasons. It was concluded that dependent on season, the age of the bull significantly influenced qualitative and quantitative attributes of semen; age-wise quality improvement was substantial in FSD but negligible in Non-FSD bulls after two years. The study recommended that germplasm harvest from crossbred bulls should be emphasized during the summer and winter seasons for more FSD production. Two-year-old bulls with SQI &lt;50 should be culled immediately because their semen quality did not improve afterward. Adoption of stress amelioration during the rainy season might help increase semen quality and FSD production in crossbred bulls under tropical climatic conditions. 

https://malque.pub/ojs/index.php/avr/article/download/373/308

Impact of seasons and management factors on seminal attributes and frozen semen doses production in Holstein Friesian crossbred dairy bulls

MicroRNAs (miRNAs) are involved in post-transcriptional gene regulation and single miRNAs regulating multiple mRNAs targets. Using bioinformatics approaches, this work aims to identify and characterize the miRNAs that could potentially bind with PDKCC, AP3S2 and SEC61A2 gene which regulate protein transport during heat stress. To resolve this problem, three freely available online miRNAs target finder databases were applied to identify the potential miRNAs which may target PDKCC, AP3S2 and SEC61A2 gene. The prediction results showed that a total of 115, 67 and 25 miRNAs for PDKCC, 267, 111 and 12 miRNAs for AP3S2 and 92, 120 and 31 miRNAs for SEC61A2 were identified as a possible potential candidate by TargetScan, MirTarget2 and miRanda respectively. Following the clustering process, we found eight miRNAs for PDKCC, three for AP3S2 and nine for SEC61A2s identified as possible candidates by all three databases. Five miRNAs in PDKCC, four in AP3S2 and five in the SEC61A2 gene have 100% identical sequence resemblance between human and bovine miRNAs. miRNAs binding site analysis showed that miR-34a in AP3S2 and miR-377 in SEC61A2 has the highest number of binding sites while miR-30b and miR-30c have two binding sites in 3´UTR of SEC61A2 gene whereas the rest of the miRNAs have the lowest number of the binding site in PDKCC and SEC61A2 gene respectively. Our study identified total four potential miRNAs that have different binding sites at the AP3S2 and SEC61A2 3´UTR site along with seven miRNAs which have single binding site and can modulate protein transport, translocation and other cellular pathways.

Mahesh Kumar

Papers

Glass formation and topology in relation to free volume, glass transition and band structure in Ge-Se-Sb chalcogenide system

Fabrication and modeling of laser ablated NiO nanoparticles decorated SnO2 based formaldehyde sensor

Ion implantation in \b{eta}-Ga2O3: physics and technology

Impact of seasons and management factors on seminal attributes and frozen semen doses production in Holstein Friesian crossbred dairy bulls

In silico identification of miRNAs potentially targeting the genes that regulate protein transport and translocation in cattle in heat stress response