Synthesis of 2-Alkynoates by Palladium(II)-Catalyzed Oxidative Carbonylation of Terminal Alkynes and Alcohols

A homogeneous Pd(II) catalyst, utilizing a simple and inexpensive amine ligand (TMEDA), allows 2‐alkynoates to be prepared in high yields by an oxidative carbonylation of terminal alkynes and alcohols. The catalyst system overcomes many of the limitations of previous palladium carbonylation catalysts. It has an increased substrate scope, avoids large excesses of alcohol substrate and uses a desirable solvent. The catalyst employs oxygen as the terminal oxidant and can be operated under safer gas mixtures

Investigations on tool wear behavior in turning AISI 304 stainless steel: An empirical and neural network modeling approach

Machining with a cutting edge with extensive damage or a fractured cutting edge significantly influences the machining performance. Therefore, investigations on tool wear behavior, their forms, and wear mechanisms will be very helpful in the current environment of sustainable manufacturing. On the other hand, the machining economy is negatively impacted by replacing the tool well before its useful life. This proactive maintenance planning reduces the risk of sudden tool failure and potential workpiece damage. Accordingly, the current work creates empirical and ANN models to predict flank wear growth for turning AISI 304 stainless steel using a MTCVD-TiCN/Al2O3 coated carbide tool. The experiments were designed to cover a broad range of operating conditions to ensure the model's accuracy and applicability in practical machining scenarios. An ANN was modeled using a feedforward backpropagation machine learning technique. In this study, a higher prediction accuracy of 0.9975 was achieved with ANN model as compared to the empirical model. The most common wear mechanism observed is metal adhesion, followed by fracture due to the pulling away of adhered material. The developed models have been found to be valuable for optimizing cutting parameters and enhancing tool life in machining.&nbsp

WEB SCALE INFORMATION EXTRACTION USING WRAPPER INDUCTION APPROACH

Information extraction from unstructured, ungrammatical data such as classified listings is difficult because traditional structural and grammatical extraction methods do not apply. The proposed architecture extracts unstructured and un-grammatical data using wrapper induction and show the result in structured format. The source of data will be collected from various post website. The obtained post data pages are processed by page parsing, cleansing and data extraction to obtain new reference sets. Reference sets are used for mapping the user search query, which improvised the scale of search on unstructured and ungrammatical post data. We validate our approach with experimental results

Anomalous transport in Kane fermions

Kane fermions are characterized by a linear Dirac cone intersecting with a flat band, resembling a pseudo-spin-1 Dirac semimetal. Similar to relativistic Dirac fermions, Kane fermions satisfy a linear energy-momentum relation and can be classified as being pseudo-relativistic. Though not protected by symmetry or by topology, Kane fermions can emerge by suitable band engineering, for example, in mercury-telluride compounds. Here we study the Berry curvature of Kane fermions that emerges in the presence of time-reversal symmetry breaking weak Zeeman fields. We discuss the related anomalous transport coefficients and discuss the anisotropy in these responses that can be probed in experiments.Comment: 4 pages, 5 figure

Disentanglement, disorder lines, and Majorana edge states in a solvable quantum chain

We study the exactly solvable 1D model: the dimerized $XY$ chain with uniform and staggered transverse fields, equivalent upon fermionization to the noninteracting dimerized Kitaev-Majorana chain with modulation. The model has three known gapped phases with local and nonlocal (string) orders, along with the gapless incommensurate (IC) phase in the $U(1)$ limit. The criticality is controlled by the properties of zeros of model's partition function, analytically continued onto the complex wave numbers. In the ground state they become complex zeros of the spectrum of the Hamiltonian. The analysis of those roots yields the phase diagram which contains continuous quantum phase transitions and weaker singularities known as disorder lines (DLs) or modulation transitions. The latter, reported for the first time in this model, are shown to occur in two types: DLs of the first kind with continuous appearance of the IC oscillations, and DLs of the second kind corresponding to a jump of the wave number of oscillations. The salient property of zeros of the spectrum is that the ground state is shown to be separable (factorized) and the model is disentangled on a subset of the DLs. From analysis of those zeros we also find the Majorana edge states and their wave functions.Comment: 15 pages, 13 figures; V.2 - minor corrections, version to be publishe

A clinical study of fetomaternal outcome in pregnancy with polyhydramnios

Background: Amniotic fluid not only provides protection to the fetus from traumatic forces, cord compression, and microbial pathogens, but also plays an integral role in the normal development of the fetal musculoskeletal, pulmonary, and gastrointestinal systems. Polyhydramnios, defined as an excessive amount of amniotic fluid, complicates approximately 0.4-3.3% of all pregnancies. Fetal conditions that are associated with polyhydramnios include major congenital anomalies and both the immunologic and non-immunologic forms of hydrops foetalis. Maternal medical conditions are also known to be associated with polyhydramnios and subsequently alter perinatal outcome. So by diagnosing these cases as early as possible, these maternal complications can be prevented and advise proper prenatal counseling in relevant cases.Methods: This study was conducted in obstetrics and gynaecology department at a tertiary care hospital, over the period of from September 2015 to September 2016. Prospective observational study.Results: Polyhydramnios is commoner in primigravida. Causative factor are mainly idiopathic after which the most important is fetal defects. Diabetes is also associated finding with polyhydramnios in 8.3% cases. The occurrence of fetal congenital abnormality was directly proportional to the gestational age of pregnancy. Incidence of congenital abnormality was found to be 1.25 %. Congenital heart disease and cleft lip and cleft palate (3%) were the commonest congenital abnormality associated with polyhydramnios followed by anencephaly and spina bifida (3.3%).Conclusions: In our study Idiopathic polyhydramnios was found to be the most common cause of polyhydramnios. A careful study must be done for detection of etiological factors in all cases of polyhydramnios, careful screening, prenatal and antenatal counseling will help to improve the foetal outcome as well as to prevent the maternal complication

Drug repurposing in the treatment of COVID-19: A review

The first outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was in Wuhan, Hubei, China in December 2019 and declared as a pandemic by the World Health Organization. Currently, there is no proven effective vaccine or therapeutic agent to combat the deadly coronavirus disease. Currently, prevention from the infection, control measures and supportive care help to treat against COVID-19. Until an effective vaccine is available for COVID-19 infection, one can repurpose known therapeutic agents that block the entry of the virus into the host cell and control the COVID-19 infection. Drug repurposing is the new use of old drugs. In this review, the most common and possible drug treatment for COVID-19 is highlighted. The therapeutic agents include antiviral drugs like Remdesivir, chloroquine, hydroxychloroquine, lopinavir/ritonavir, umifenovir, favipiravir and oseltamivir and other agents. Clinical trials are ongoing to evaluate the safety and efficacy of these therapeutic agents in COVID-19 patients

A cold atom apparatus for the microscopy of thin membranes

Ultracold atomic gases can be utilised as extremely sensitive probes of their surrounding environment. In particular, samples of ultracold atoms confined using chip-based microtraps are an ideal tool for mapping electric and magnetic field landscapes. Over the course of this thesis, a new experiment capable of performing surface microscopy using magnetically trapped clouds of cold rubidium-87 atoms has been built. The focus of the work is on the design and construction of the experimental system, which must incorporate many different aspects for manipulating thermal atomic gases, with a view to positioning them at sub-micron distances from special surfaces. This reduced atom-surface separation is necessary for implementing a high resolution, high sensitivity magnetic field sensor with cold atoms. Although current microfabrication techniques easily enable trapping at distances on the order of micrometres, several distance-dependent surface effects - such as the Casimir-Polder force, Johnson-Nyquist noise, and stray potentials - eventually impede magnetic trapping at the sub-micron level. These surface effects can greatly modify the confining potentials, which reduces the trap depth and consequently leads to an additional loss rate of atoms from the trap. We have explored the possibility of using special surfaces such as nano-membranes of silicon nitride and graphene, which have reduced atom- surface interactions, to enable trapping distances at the sub-micron level. A multilayer printed circuit board chip has been designed to form an initial magnetic trap and then transport the cloud of atoms to a desired location over the samples. This chip, along with various samples, is mounted on a custom-made electrical feedthrough designed to make connections to all conductor that are inside the vacuum chamber. The initial cloud of cold atoms can then be prepared in the central region of the chip and delivered to the location of the samples on either side. The experimental system is able to routinely capture over 10^8 rubidium-87 atoms at a temperature of 80 micro-Kelvin in a magneto-optical trap using a novel scheme of five laser beams. A method is demonstrated for enhancing the atom number in the magneto-optical traps by a factor of two by using laser beams with two slightly different frequencies. Atoms from the magneto-optical trap are then transferred to a purely magnetic trap formed by the wires on the printed circuit board chip. Time-dependent currents in the chip wires then create a dynamic potential, which is shown to successfully transport the atomic sample over a distance of 12 millimetre with minimal atom loss. This thesis describes the development of the apparatus in detail, along with careful characterisation of the cold cloud at various stages of the experimental sequence. Initial results on the long distance atom transport are presented. Finally, the experimental results of the two frequency magneto-optical trap for atom number improvement are discussed

Analysis of Soil Health Card awareness and Constraints among Farmers in Vidarbha Region

This study is conducted to assess the awareness levels of farmers regarding the Soil Health Card and identify the constraints they encountered in utilizing its information in the Vidarbha region of Maharashtra state. The research was conducted in Chandrapur district, specifically in the talukas of Warora, Bhadravati, Jivti, and Rajura. Three villages were selected from each taluka and ten respondents were selected from each village, resulting in a total of 120 purposively selected respondents for the study. Data collection involved personal interviews using a structured interview schedule. The findings revealed that slightly over half of the respondents (54.17%) had a moderate level of awareness about the Soil Health Card, while a quarter of the farmers (25.00%) had low awareness, and just over twenty per cent (20.83%) had a high level of awareness. The study also examined the distribution of respondents based on the constraints they faced and their efforts to overcome these challenges. These findings contribute to our understanding of the awareness and constraints faced by farmers in effectively utilizing the information from the Soil Health Card, highlighting the need for targeted interventions and support to improve its implementation in the region