Variability of mesopause temperature derived from two independent methods using meteor radar and its comparison with SABER and EOS MLS and a collocated multi-wavelength dayglow photometer over an equatorial station,Thumba (8.5° N, 76.5° E)

Two independent methods for deriving mesopause temperature using meteor radar installed at an equatorial station, Thumba (8.5° N, 76.5° E), are discussed in this article. This meteor radar-derived mesopause temperature is then compared with two different types of spaceborne measurement, namely (i) Sounding the Atmosphere using Broadband Emission Radiometry (SABER) and (ii) the Earth Observing System Microwave Limb Sounder (EOS MLS), and a collocated multi-wavelength dayglow photometer (DGPM). The meteor radar-derived temperature is in fairly good agreement with all the three measurement techniques, with an uncertainty of ±10°. This study focuses on a detailed evaluation and inter-comparison of mesopause temperature derived from different measurement techniques. An attempt is also made to compare the suitability of these observations to study planetary waves and other oscillation activities in the mesospheric region.     

THz antennas design,developments, challenges,and applications: A review

Terahertz (0.1–10 THz) wireless communication will be the future technology to reach a top-notch data rate. THz is one of the most promising candidates for 6G systems because it provides enormous bandwidth, up to 100 GHz, and a massive data rate of up to 1 Tbps. THz antennas, antenna arrays, and MIMO antenna arrays in 6G are hot research topics for implementing 6G wireless communication systems. The 6G aims to continue to enhance the features of the 5G as it is capable of achieving the maximum high-speed data rate, excellent reliable communication, massive connectivity, and very low latency connectivity. The 6G requirements need high-gain antenna arrays and MIMO antenna arrays to combat the effect of atmospheric losses in high frequencies. An in-depth discussion of the planar THz antennas that have been extensively used in THz applications like imaging, sensing, and Internet-of-Things (IoT) has been conducted. The study of the THz antennas, antenna arrays, and MIMO antennas on different conducting materials such as copper and graphene, which are designed on different dielectric substrates such as polyimide, quartz, liquid crystalline polymer, and polytetrafluoroethylene, has been carried out in detail. Metamaterial, photoconductive, plasmonic antennas, and THz beamforming are significant parts of THz communications. This paper also provides antennas and antenna arrays based on them.     

Identification of single nucleotide polymorphisms in the bovine interleukin-12 and interleukin-23 receptor genes and their associations with health and production traits in Holstein cows

Interleukin-12 (IL-12) and interleukin-23 (IL-23) are proinflammatory cytokines produced by macrophages and dendritic cells in response to infection with intracellular pathogens. The IL-12 receptor (IL-12R) is a heterodimer composed of 2 subunits, β1 and β2. The IL-23 receptor (IL-23R) is a heterodimer composed of the IL-12Rβ1 subunit and a unique IL-23R subunit. Given the importance of IL-12 and IL-23 for modulating inflammation and the host immune response, the IL-12 and IL-23 receptor genes may be suitable candidate genes for studying disease resistance in dairy cattle. We hypothesize that single nucleotide polymorphisms (SNP) exist within these genes and that they contribute to variation in health and production traits in dairy cattle. To investigate this, a selective DNA pool was constructed using bull semen based on the estimated breeding values for somatic cell score (SCS), an indicator trait used to achieve genetic improvement for resistance to mastitis. Gene segments were amplified from this pool by PCR and the amplicons were sequenced to reveal SNP. A total of 10 SNP, including 2 in IL-12Rβ1, 5 in IL-12Rβ2, and 3 in IL-23R were identified. The SNP (n = 5) were found in the 5′ untranslated region (UTR) putative promoter regions of the genes, and SNP IL-23R c.1714A > C was a nonsynonymous SNP. Canadian Holstein bulls (n = 492) were genotyped using Sequenom MassARRAY (Sequenom Inc., San Diego, CA). No association was found with SCS based on bull deregressed estimated breeding values for SCS; however, associations of SNP in the IL-12Rβ2 gene (c.-511A > G, c.87A > G, c.2957A > C) were found with milk and protein yield. Further investigation will be required to elucidate the biological and practical relevance of these SNP.     

A self-tuning fuzzy PI controller for TCSC to improve power system stability

In this paper, a self-tuning fuzzy PI controller (STFPIC) is proposed for thyristor-controlled series capacitor (TCSC) to improve power system dynamic performance. In a STFPIC controller, the output-scaling factor is adjusted on-line by an updating factor (α). The value of α is determined from a fuzzy rule-base defined on error (e) and change of error (Δe) of the controlled variable. The proposed self-tuning controller is designed using a very simple control rule-base and the most natural and unbiased membership functions (MFs) (symmetric triangles with equal base and 50% overlap with neighboring MFs). The comparative performances of the proposed STFPIC and the standard fuzzy PI controller (FPIC) have been investigated on two multi-machine power systems (namely, 4 machine, 2 area system and 10 machine 39 bus system) through detailed non-linear simulation studies using MATLAB/SIMULINK. From the simulation studies it has been found out that for damping oscillations, the performance of the proposed STFPIC is better than that obtained by the standard FPIC. Moreover, the proposed STFPIC as well as the FPIC have been found to be quite effective in damping oscillations over a wide range of operating conditions and are quite effective in enhancing the power carrying capability of the power system significantly.     

Hydroisomerization of n-hexadecane over Brønsted acid site tailored Pt/ZSM-12

Hydroisomerization of n-hexadecane is performed over ZSM-12 framework having tailored Brønsted acidity to investigate the effect in terms of product selectivity and yield. For this purpose, pure phase of ZSM-12 (bulk molar ratio Si/Al ~ 60) has been synthesized using TEABr as a structure directing agent. The framework Brønsted acidity is tailored with group II elements (M) viz. Ca, Ba and Mg, by means of ion-exchange method. The samples so prepared have been characterized for phase purity, textural parameters, morphology by employing powder X-ray diffraction, nitrogen adsorption–desorption isotherm measurement at 77 K, and scanning electron microscopy technique, respectively. Similarly, % metal exchange is estimated using inductively coupled plasma technique. The quantification of Brønsted acidity for H⁺–M⁺⁺–ZSM-12 samples has been estimated by means of ammonia temperature programmed desorption (NH₃-TPD) and Fourier transform infrared spectroscopy of ammonia (NH₃-FTIR). The well characterized H⁺–M⁺⁺–ZSM-12 samples were loaded with Platinum (Pt, 0.5 wt%) and subjected to hydroisomerization of n-hexadecane using an up-flow fixed bed reactor to verify the effect of process parameters like temperature and WHSV. Pt/H⁺–Ba²⁺–ZSM-12 with tailored Brønsted acidity in the range of about 25 % demonstrated the optimum performance among all the catalysts with an increased isomer selectivity and yield (89.2 and 80.3 %, respectively) by about 4 wt% at a conversion level of about 90 % compared to Pt/H⁺–ZSM-12 framework at 568 K. Such enhancement in isomer selectivity and yield is found to be significant from commercial application point of view. Based on the obtained trend, the potential benefits of implementation of Pt/H⁺–Ba²⁺–ZSM-12 (bulk molar ratio Si/Al ~ 60) framework for cold flow property improvement of ‘bio-ATF’ have been envisaged.     

Analysis of a Multiphase Induction Machine Under Fault Condition in a Phase-Redundant A.C. Drive System

Phase-redundancy is a unique technique for improving the reliability of large variable speed AC drives. This technique, derived from the concept of parallel-redundancy, is based on the capability of a multiphase machine to start and continue running with one or more of its many stator phases open or short circuited with lower performance. Structural unbalance in the machine following loss of excitation is the main source of performance degradation. This paper, therefore, presents a simple generalized approach to analyze the dynamic as well as steady-state behavior of a multiphase induction machine during fault condition in a phase-redundant AC drive system. The key analytical results have been experimentally verified by tests conducted on a laboratory prototype.     

A new nitrogen alloying technique - a way to distinctly improve the properties of austenitic steel

The paper presents a new process for nitrogen alloying austenitic steels beyond solubility limit in a pressurized electroslag remelting furnace using Si₃N₄ as nitrogen source. With the aid of this process it is possible to attain nitrogen percentages far beyond the solubility limit at atmospheric pressure. These high nitrogen contents impart a distinct improvement to the properties of the material. Yield strengths R_p0.2>600 N/mm² at ambient temperature are achieved. The high tensile values are attributable to the lattice expanding effect of force-dissolved nitrogen. A reduction in forming characteristics A₅ and Z normally associated with a distinct increase in tensile strength is not noticeable. The tests at ambient temperature have further shown that nitrogen alloyed steels display high fatigue strength values. If results of the fatigue tests are evaluated on the basis of the empirical relation 0.30 < σ_zdw/R_m<0.45 it is found that the values of the steels tested are generally at the upper limit of this value or even above it. The very good creep test results of nitrogen alloyed steels deserve emphasis. Up to 800°C they are comparable to the creep values of high temperature alloys. This is attributable to the precipitation behaviour of the steels caused by the presence of nitrogen. Embrittlement occurs only to a very small extent and precipitates, in particular Cr₂N, enhance creep resistance owing to their favourable arrangement. The new technique of nitrogen alloying beyond the solubility limit opens up favourable opportunities for nitrogen alloyed austenitic steels in new applications. This development offers further advantages in that considerable savings in nickel as an alloying element can be made and that material can be much better utilized in the design of components.     

Nature of growth inhibitors for Trogoderma granarium Everts (Coleoptera: Dermestidae) in lentil (Lens esculenta Moench.) and French bean (Phaseolus vulgaris L.)

Steaming of lentil (Lens esculenta Moench.) and French bean (Phaseolus vulgaris L.) made them suitable for Trogoderma granarium Everts. Addition of glucose, casein, cholesterol, lard, nucleic acid, McCollum salt mixture, vitamins of the B group and -methionine indicated that the poor food value of lentil was due to the presence of heat labile inhibitor and dietary deficiency of cholesterol. But in the case of French bean heating probably facilitated, apart from destruction of heat labile inhibitor, the release of an assimilable form of carbohydrate needed for proper growth and development. The possibility of the presence of qualitatively and/or quantitatively different types of inhibitors in these pulses was suspected.     

Renewable hydrogen generation by steam reforming of glycerol over zirconia promoted ceria supported catalyst

The study focuses on hydrogen production from steam reforming of glycerol over nickel based catalyst promoted by zirconia and supported over ceria. Catalyst was prepared by the wet-impregnation method and characterized by BET surface area analysis, X-ray diffraction technique and scanning electron microscopy (SEM) analysis. The performance of the catalyst was evaluated in terms of hydrogen yield, selectivity and glycerol conversion at 700 °C in a tubular fixed bed reactor. The effect of glycerol concentration in feed, space time (W/F_AO), temperature and time on stream (TOS) was analyzed for the catalyst Ni–ZrO₂/CeO₂ which showed the complete conversion of glycerol and high H₂ yield that corresponds to 3.95 mol of H₂ out of 7 mol. Thermodynamic analysis was also carried out using Aspen HYSYS for system having glycerol concentration 10 wt% and 20 wt% and experimental results were compared with thermodynamics. Kinetic study was carried out for the steam reforming of glycerol over Ni–ZrO₂/CeO₂ catalyst using the power law model. The values of activation energy and order of reaction were found to be 43.4 kJ/mol and 0.3 respectively.