Archives, Room Use Only - TK5115.R45 1919

Archives, Room Use Only - TK5262.R46 1924

Archives, Room Use Only - UG590.S54 1838

Archives, Room Use Only - TK6169.W47 1934

Archives, Room Use Only - QC527.T73 1895

Archives, Room Use Only - KFP301.A3 1884

Around 3,500 Indians stranded abroad had been flown into India until the wee hours on Sunday as India’s Vande Bharat Mission motored ahead under what official sources described as regular high-level oversight. While eight flights landed across India on Saturday — Day 3 — an equal number was expected on Sunday. Around 2K will be arriving from the Maldives.

The chopper was inducted into service in March last year.

Followers and politicians did not flock 'Chaitya Bhoomi', the Constitution architect's memorial in central Mumbai.

The city Corporation has made elaborate arrangements for non-resident Keralites ahead of the landing of the first flight from Doha in the capital on S

It is now the fifth hardest-hit country with 200,000 infections; Putin hails ‘unity’ in speech marking Second World War win

THANJAVUR The All India Trade Union Congress will be organising a demonstration on May 11 to press the Union and State governments to expedite the pro

The Trump administration is tightening visa guidelines for Chinese journalists in response to the treatment of US journalists in China, as tensions flare between the two nations over the coronavirus.

Hong Kong: Trump administration tightens visas for Chinese reporters - Times of India

Gas leak fallout: CPCB asks industrial units across India to go for safety and hazard audit before resuming operations

Around 75% pharma units operational in Gujarat: FDCA

BJP functionaries fight over ration distribution

Vande Bharat operations: 3,500 fly back in 3 days

The teacher was posted at a primary school in Wazirabad under the North Delhi Municipal Corporation.

Migrants, tribals have no money to buy food due to lockdown: PIL

With confusion prevailing over opening of shops, the district administration has issued clarification and released list of shops that can be opened an

This is the Indian Navy’s first massive evacuation exercise during the Covid-19 lockdown

Further details are awaited.

According to a report by security agencies, the presence of around 450 terrorists, including those from Lashkar-e-Taiba (LeT), Hizbul Mujahideen (HM) and Jaish-e-Mohammad (JeM), has been seen on the launching pads adjacent to the Line of Control (LoC).

A multi-color light source is a significant tool for nonlinear optics experiments, pump–dump/repump–probe experiments and in other fields. Here, a novel method is proposed to create three-color pulses based on a high-gain harmonic-generation (HGHG) free-electron laser with a tilted electron bunch. In this method, the initial bunch tilt is created by transverse wakefields after the bunch passes through a corrugated structure with an off-axis orbit, and is further enlarged in a following drift section. Then the tilted bunch experiences the off-axis field of a quadrupole magnet to cool down the large transverse velocity induced before. After that, it enters an HGHG configuration adopting a transverse gradient undulator (TGU) as the radiator, where only three separated fractions of the tilted bunch will resonate at three adjacent harmonics of the seed wavelength and are enabled to emit three-color pulses simultaneously. In addition, the use of the natural transverse gradient of a normal planar undulator instead of the TGU radiator to emit three-color pulses is also studied in detail. Numerical simulations including the generation of the tilted bunch and the free-electron laser radiation confirm the validity and feasibility of this scheme both for the TGU radiator and the natural gradient in the extreme-ultraviolet waveband.

An analysis of the coherence properties of the fourth-generation high-energy storage rings with emittance values of 10 pm rad is performed. It is presently expected that a storage ring with these low emittance values will reach diffraction limit at hard X-rays. Simulations of coherence properties were performed with the XRT software and an analytical approach for different photon energies from 500 eV to 50 keV. It was demonstrated that a minimum photon emittance (diffraction limit) reached at such storage rings is λ/2π. Using mode decomposition it is shown that, for the parameters of the storage ring considered in this work, the diffraction limit will be reached for soft X-ray energies of 500 eV. About ten modes will contribute to the radiation field at 12 keV photon energy and even more modes give a contribution at higher photon energies. Energy spread effects of the electron beam in a low-emittance storage ring were analysed in detail. Simulations were performed at different relative energy spread values from zero to 2 × 10−3. A decrease of the degree of coherence with an increase of the relative energy spread value was observed. This analysis shows that, to reach the diffraction limit for high photon energies, electron beam emittance should go down to 1 pm rad and below.

Calibration of area detectors from powder diffraction standards is widely used at synchrotron beamlines. From a single diffraction image, it is not possible to determine both the sample-to-detector distance and the wavelength, but, with images taken from multiple positions along the beam direction and where the relative displacement is known, the sample-to-detector distance and wavelength can both be determined with good precision. An example calibration using the GSAS-II software package is presented.

A simple two-spindle based lathe system for the preparation of cylindrical samples intended for X-ray tomography is presented. The setup can operate at room temperature as well as under cryogenic conditions, allowing the preparation of samples down to 20 and 50 µm in diameter, respectively, within minutes. Case studies are presented involving the preparation of a brittle biomineral brachiopod shell and cryogenically fixed soft brain tissue, and their examination by means of ptychographic X-ray computed tomography reveals the preparation method to be mainly free from causing artefacts. Since this lathe system easily yields near-cylindrical samples ideal for tomography, a usage for a wide variety of otherwise challenging specimens is anticipated, in addition to potential use as a time- and cost-saving tool prior to focused ion-beam milling. Fast sample preparation becomes especially important in relation to shorter measurement times expected in next-generation synchrotron sources.