Stable and Metastable vortex states and the first order transition across the peak effect region in weakly pinned 2H-NbSe_2

The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et al, Phys. Rev. B 61, R6479 (2000)] proposed to explain the history dependent J_c postulates a stable state of vortex lattice with a critical current density J_c^{st}, determined uniquely by the field and temperature. In this paper, we present evidence for the existence of the stable state of the vortex lattice in the peak effect region of 2H-NbSe_2. It is shown that this stable state can be reached from any metastable vortex state by cycling the applied field by a small amplitude. The minor magnetization loops obtained by repeated field cycling allow us to determine the pinning and "equilibrium" properties of the stable state of the vortex lattice at a given field and temperature unambiguously. The data imply the occurence of a first order phase transition from an ordered phase to a disordered vortex phase across the peak effect.Comment: 20 pages, 10 figures. Corresponding author: S. Ramakrishna

An Investigation on the Influence of Modeling Approach and Load Pattern on Seismic Performance of RC Structures

Non-linear Static Analysis serves as a suitable measure to evaluate the performance of a structural system. The careful selection of modelling approach and the load pattern is critical to arrive at an adequate performance evaluation. The present study seeks to evaluate and compare the response of an existing eight story reinforced concrete structure, through the application of different modeling approaches and load patterns prescribed by FEMA 356. The results indicates that, with extreme clarity, that in all cases, the shape of the lateral load distribution is what the response of the buildings is finely accustomed to. This is especially true when different patterns of load are considered. It can also be observed that there is a very small difference between various load patterns

Occupational Risk Factors and Preventive Measures for COVID-19 In Prosthodontics

Today, novel coronavirus infection has become pandemic worldwide. It is the major cause of sickness from the common cold to severe acute respiratory syndrome in individuals. In a dental operatory, infections can be expedited through several routes like aerosol generation, contaminated surfaces, droplet splatter, oral fluids, and direct contact. Keeping in mind about the routes of transmission of COVID-19 (Coronavirus disease-19), dental practitioners are at higher risk of exposure and disease spread. Hence, this review article emphasizes the routes of transmission, risk factors, prophylactic and preventive measures. It also sights on alternative approaches to prosthodontic procedures to reduce the burden of COVID-19 infection in their community. Data acquisition was made using the keywords, COVID-19, infection control, prosthodontic risk factors in electronic databases like PubMed, Medline, ProQuest, etc. A manual search of several journals and books was also carried out, and only highly relevant articles were considered for the present review

Likelihood Ratio Type Test for Linear Failure Rate Distribution vs. Exponential Distribution

The Linear Failure Rate Distribution (LFRD) is considered. The graphs of its probability density function are examined for selected parameter combinations. Some of them are similar to the well-known exponential distribution. Incidentally exponential distribution is one of the two component models of the LFRD model. In view of the simpler form of exponential model as applicable in inference, looking at the frequency curves of LFRD, a test statistic is proposed based on ratio of likelihood functions containing the standard forms of the density functions of both LFRD and Exponential to discriminate between LFRD and exponential models. The critical values and the powers of the test statistic are developed

Integrated nutrient management - promising way to reduce carbon dioxide and methane emission in flooded rice ecosystem: A review

Climate change is an inevitable ruling issue caused by the increasing concentration of greenhouse gases (GHG’s) in the atmosphere worldwide. It will have a considerable impact on agriculture and its related fields like live stocks and fisheries. In India, the main sectors contributing to these emissions are industry, agriculture and waste, with a total emission of 334 MT CO2 eq. Besides, the major sources in agriculture are enteric fermentation (63.4%), rice cultivation (20.9%), agricultural soils (13.0%), manure management (2.4%) and on-field burning is the crop residue (2.0%). Thus, the crop productivity sector (rice cultivation, soil and field burning of crop residues) contributes 35.9% to the total emission from agriculture. Therefore, reducing GHG emissions and enhancing the C sequestration in soil and biomass has become challenging. However, the total GHG’s emission from all sectors of the country has decreased from 33% in 1970 to 18% in 2010. Cutting off GHGs emission from agriculture can be achieved by sequestering C and reducing methane emissions(CH4) and carbon dioxide(CO2) through various soil and crop management strategies. Integrated nutrient management (INM) practice ensures the Soil –plant –atmospheric continuum (SPAC) in a  promising way, reducing the GHGs emission by sequestering more carbon to soil than emissions. A studious prominent INM solution can be identified to develop a mitigation strategy that helps in climate change adaptation and sustains soil health through soil carbon sequestration

Comparison of History Effects in Magnetization in Weakly pinned Crystals of high-TcT_c and low-Tc_c Superconductors

A comparison of the history effects in weakly pinned single crystals of a high $T_c$ YBa$_2$Cu$_3$O$_{7 - \delta}$ (for H $\parallel$ c) and a low $T_c$ Ca$_3$Rh$_4$Sn$_{13}$, which show anomalous variations in critical current density $J_c(H)$ are presented via tracings of the minor magnetization hysteresis loops using a vibrating sample magnetometer. The sample histories focussed are, (i) the field cooled (FC), (ii) the zero field cooled (ZFC) and (iii) an isothermal reversal of field from the normal state. An understanding of the results in terms of the modulation in the plastic deformation of the elastic vortex solid and supercooling across order-disorder transition is sought.Comment: Presented in IWCC-200

Preparation of water hyacinth-based phosphocompost and its evaluation against certain phosphorus fertilizers along with phosphate solubilizing bacteria on P availability, uptake and rice productivity

Phosphorus (P) deficiency in soil limits crop yields and can be managed by P fertilizers. But mere applying P fertilizers alone may not be effective in justifying its bioavailability. At present global P reserves are declining in an increasing way which urges us to find out alternatives. Thus, the present work was taken to prepare phosphocompost using water hyacinth (Eichhornia crassipes) as feedstock, termite, and normal soil as bulking agents cum decomposers and enriched with single super phosphate. The effect of phosphocompost on rice(var.ADT-43) productivity, P availability and uptake was evaluated by comparing various P fertilizers (single super phosphate, rock phosphate, di-ammonium phosphate, nano phosphate) combined with or without phosphate solubilizing bacteria (PSB). The experiment was laid out in a completely randomized design with seven treatments including absolute control and replicated thrice. Phosphocompost produced with water hyacinth and termite soil microbes come with superior quality and early maturity compared to normal soil. Pot culture study results revealed that rice growth, yield, P availability and uptake were significantly (p<0.05) higher with SSP + PSB, and Nano phosphate +PSB treated plants, followed by Phosphocompost + PSB. The cost of P fertilizer (Rs/ha) related to yield (kg/ha) was found to be significantly low with phosphocompost (Rs.1132/-) than SSP (Rs.1530/-) and Nano P (Rs.2518/-). Further, phosphocompost combined PSB helps in optimizing the P availability in a long run through P solubilization thus sustained the P uptake. The present investigation brings light to the valorization of water hyacinth as compost will be an effective and economically viable alternative for P fertilizers

Response of rice (Oryza sativa L.) productivity and nutrient uptake to nitrogen and boron fertilization in Typic Ustifluvents soil

Nitrogen and boron are necessary for the metabolic activities of rice for its growth. With this perspective, a field experiment was conducted in farmer’s field during 2020 at Kuttalam, Mayladuthurai district, Tamilnadu in sandy clay loam(Padugai Series – TypicUstifluvents) to predict the response of rice (Oryza sativa) to different levels of nitrogen(N) and boron (B) application. The treatments consisted of Factor A- Nitrogen levels, 0, 75, 150, 225 kg ha-1 and Factor B- Boron levels 0, 1.5, 3.0 kg ha-1. Fifteen treatments were conducted in a Factorial randomised block (FRBD) design with three replications.  The test crop was rice with a variety ADT 46.    Concerning nitrogen alone, the highest grain (5344 kg ha-1) and straw yield was recorded in N3(225 kg ha-1). Among the boron levels tested, the highest grain (4695 kg ha-1) and straw yield (6509 kg ha-1) was registered in B1 (1.5 kg ha-1) in rice. The highest total nutrient uptake viz., N(88.2 kg ha-1), P(30.5 kg ha-1), K(105.0 kg ha-1) and B(172mg kg-1)  were recorded in N3B1. Among the N alone, the highest total nutrient uptake viz., N(78.1kg ha-1, P(26.3kg ha-1), K (95.8 kg ha-1) and B(156.6 mg kg-1) in N3. Concerning B alone, the highest nutrient uptake viz., N(60.5, kg ha-1) , P(17.8kg ha-1) K(74.9 kg ha-1) and B(112.1mg kg-1) were registered in B1 over other B levels. The highest grain (5631 kg ha-1) was recorded in N3B1 (225 kg N ha-1 and 1.5kg B ha-1) than other interactions. The study concluded that applying nitrogen and boron is required to achieve the maximum yield of rice in sandy clay loam soil

A comprehensive review on bonding between monolithic ceramics and tooth structure with different adhesive agents.

Reliable bonding between the prepared tooth and monolithic ceramics can be achieved by various luting agents available on the market. The selection of luting agent and cementation technique plays an important role in the success of the restoration. With the advent of resin-based adhesive systems as luting agents, clinicians\u27 perspectives have changed to a more conservative approach. Recent systems, chemically adhere the crowns to the prepared tooth structure showing higher bond strength. To reach the aesthetic demands of the patients, all-ceramic restorations were considered over metal-ceramic crowns. Few all-ceramic crowns are brittle, the strength is dependent on the chemical structure and method of fabrication. While some all-ceramic restorations gain strength after cementation. Thus, the choice of luting agent used in cementing all-ceramic crowns is crucial. Even though many luting agents are being introduced no single luting agent fulfilled all the requirements. Among them, adhesive cements showed greater bond strength and enhanced the retention of minimal preparation, which are less retentive. Traditional non-adhesive agents can be used in retentive preparations that bond through mechanical means rather than the chemical bond seen in newer adhesive cements. Also, surface treatments of zirconia showed greater bond strengths irrespective of the luting agent being used. These include air abrasion, acid etching, applying silane couplers, and primers that increase the surface area for adhesion. The use of all-ceramic restorations, the need for surface treatments, types of surface treatments, adhesion and adhesive agents, and evidence from current in vitro research on monolithic ceramics and tooth adhesion were all discussed in this review

Study on Micro - Nano Sized Al2O3 Particles on Mechanical, Wear and Fracture Behavior of Al7075 Metal Matrix Composites

Having Low density and being Light weight with better mechanical properties, aluminum is the most significant material and is universally used in highly critical applications like navy, aerospace and particularly automotive activities. This research work is aimed to investigate the effect of micro and nano boron Al2O3 (Alumina Oxide) to aluminium (Al) on the mechanical and wear properties of the Al composites. The micro - nano composites with 1, 2, 3 and 4 % of Al2O3 particulates in Al are fabricated using stircasting processes. It was found that an increase of Al2O3 both as micro and nano particulates content resulted in an improved hardness, enhanced tensile strength and high wear resistance. However, nano Al2O3 reinforced MMCs have better hardness, improved tensile strength and higher wear resistance as compared with micro sized Al2O3 reinforced MMCs. Grain refinement of composite and nano composite materials as compared with pure Al were observed from the microscopic images. Analysis of wornout surface and tensile fracture surface were studied by SEM analysis to examine the nature of wear and tensile fracture mode of composite samples