Vishal Ranjan - Academia.edu (original) (raw)

Papers by Vishal Ranjan

Journal of Thoracic Oncology, 2021

Strategic Analysis, 2010

International Relations • India’s Diplomatic Infrastructure and Software: Challenges for the 21st... more International Relations • India’s Diplomatic Infrastructure and Software: Challenges for the 21st Century – Kishan S. Rana (Policy, Vol. 34, No. 3, May 2010) • Changing World Order: India, EU and US—A Trialogue by B. Krishnamurthy and Geetha Ganapathy-Doré – Alok Rashmi Mukhopadhyay (Book Review, Vol. 34, No. 3, May 2010) • Realism Drives India’s Foreign Policy: The Democracy Dimension by S.D. Muni – Ashok K. Behuria (Book Review, Vol. 34, No. 4, July 2010) • War and Peace in Modern India: A Strategic History of Nehru Years by Srinath Raghavan – Medha Bisht (Book Review, Vol. 34, No. 4, July 2010) • A Contrarian Perspective! Challenge and Strategy: Rethinking India’s Foreign Policy by Rajiv Sikri – Ashok K. Behuria (Book Review, Vol. 34, No. 1, January 2010) • Name of the Game Is Interdependence – Bharat Wariavwala (Debate, Vol. 34, No. 4, July 2010) • Fairy Tale of American Decline and China’s Rise – Chintamani Mahapatra (Debate, Vol. 34, No. 4, July 2010) • Name of the Game is Interdependence: A Response – M.D. Nalapat (Debate, Vol. 34, No. 4, July 2010) • Maintaining Strategic Autonomy in an Interdependent World – Rajiv Kumar (Debate, Vol. 34, No. 4, July 2010) • Name of the Game is Interdependence: A Comment – Amitabh Mattoo • Foreign Policy Planning Efforts in India – K.P. Misra (From the Archives, Vol. 34, No. 4, July 2010) • India’s Strategic Autonomy and Rapprochement with the US – Guillem Monsonis (Vol. 34, No. 4, July 2010) • The Strange Unwillingness to Notice Iraq’s Reality – Max Singer (Vol. 34, No. 4, July 2010)

arXiv (Cornell University), Feb 2, 2021

Quantum emitters respond to resonant illumination by radiating electromagnetic fields. A componen... more Quantum emitters respond to resonant illumination by radiating electromagnetic fields. A component of these fields is phase-coherent with the driving tone, while another one is incoherent, consisting of spontaneously emitted photons and forming the fluorescence signal. Atoms and molecules are routinely detected by their fluorescence at optical frequencies, with important applications in quantum technology [1, 2] and microscopy [3-6]. Spins, on the other hand, are usually detected by their coherent response at radio-or microwave frequencies, either in continuous-wave or pulsed magnetic resonance [7]. Indeed, fluorescence detection of spins is hampered by their low spontaneous emission rate and by the lack of single-photon detectors in this frequency range. Here, using superconducting quantum devices, we demonstrate the detection of a small ensemble of donor spins in silicon by their fluorescence at microwave frequency and millikelvin temperatures. We enhance the spin radiative decay rate by coupling them to a high-quality-factor and small-mode-volume superconducting resonator [8], and we connect the device output to a newly-developed microwave single photon counter [9] based on a superconducting qubit. We discuss the potential of fluorescence detection as a novel method for magnetic resonance spectroscopy of small numbers of spins.

Day 3 Wed, February 23, 2022

The Raageshwari Deep Gas (RDG) Field in the western part of India is a tight gas reservoir (~0.1m... more The Raageshwari Deep Gas (RDG) Field in the western part of India is a tight gas reservoir (~0.1mD) with gross pay of ~700 metres at the depths of 2700-3400m TVDSS in which significant gas in place is in the low permeability volcanic reservoir. The challenge to connect the highly laminated reservoir in the most techno-commercial way was achieved by utilizing Limited Entry Fracturing Technique. The effectiveness of the limited entry technique was verified using Step rate/Step down tests, post minifrac/ mainfrac temperature surveys and pressure matching. To get to the closest approximation and calibrate the stresses, DFIT was pumped in non-pay section. Despite robust diagnostics and analysis, sub surface assessments have their own share of uncertainties. The most convincing diagnostic to confirm the efficacy of the limited entry fracturing treatment is to actually "see" the perforations erode after fracturing. Downhole Camera was deployed in one of the fractured wells for fi...

Dr Sewanti Limaye2, Dr Darshana Patil1, Dr Dadasaheb Akolkar1, Mr Pradip Fulmali1, Dr Pooja Fulma... more Dr Sewanti Limaye2, Dr Darshana Patil1, Dr Dadasaheb Akolkar1, Mr Pradip Fulmali1, Dr Pooja Fulmali1, Ms Archana Adhav1, Mr Sachin Apurwa1, Mr Sushant Pawar1, Dr Shoeb Patel1, Dr Rohit Chougule1, Dr Vishal Ranjan1, Mr Pradyumna Shejwalkar1, Ms Shabista Khan1, Mr Raja Dhasarathan1, Dr Vineet Datta1, Dr Stefan Schuster1, Dr Cynthe Sims1, Dr Prashant Kumar1, Dr Pradip Devhare1, Dr. Ajay Srinivasan1, Mr Rajan Datar1 1Datar Cancer Genetics, Nashik, India, 2 Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai 400053, India

Nature, 2021

Quantum emitters respond to resonant illumination by radiating part of the absorbed energy. A com... more Quantum emitters respond to resonant illumination by radiating part of the absorbed energy. A component of this radiation field is phase coherent with the driving tone, whereas another component is incoherent and consists of spontaneously emitted photons, forming the fluorescence signal1. Atoms, molecules and colour centres are routinely detected by their fluorescence at optical frequencies, with important applications in quantum technology2,3 and microscopy4-7. By contrast, electron spins are usually detected by the phase-coherent echoes that they emit in response to microwave driving pulses8. The incoherent part of their radiation-a stream of microwave photons spontaneously emitted upon individual spin relaxation events-has not been observed so far because of the low spin radiative decay rate and of the lack of single microwave photon detectors (SMPDs). Here using superconducting quantum devices, we demonstrate the detection of a small ensemble of donor spins in silicon by their fluorescence at microwave frequencies and millikelvin temperatures. We enhance their radiative decay rate by coupling them to a high-quality-factor and small-mode-volume superconducting resonator9, and we connect the device output to a newly developed SMPD10 based on a superconducting qubit. In addition, we show that the SMPD can be used to detect spin echoes and that standard spin characterization measurements (Rabi nutation and spectroscopy) can be achieved with both echo and fluorescence detection. We discuss the potential of SMPD detection as a method for magnetic resonance spectroscopy of small numbers of spins.

Science Advances, 2021

A scheelite crystal with residual concentration of erbium is cooled down to 10 mK, yielding a rec... more A scheelite crystal with residual concentration of erbium is cooled down to 10 mK, yielding a record spin coherence time of 23 ms.

Fast measurement of small currents and even smaller fluctuations in devices with large impedance ... more Fast measurement of small currents and even smaller fluctuations in devices with large impedance is not trivial. Standard low frequency lock-in measurements suffer from stray capacitance of the order of nF reducing the bandwidth to merely kHz and a time resolution of ms. One approach of increasing the bandwidth is to connect the high-impedance device next to a low input impedance amplifier, though, the signal is decreased by the ratio of the impedances of the device and the amplifier, easily a factor of a thousand. Therefore, long averaging times are required to detect the small signal. Moreover, 1/f noise still affects the measurements. The issues of small bandwidth, impedance mismatch and 1/f noise can be simultaneously addressed using resonant LC circuits. The success of this impedance transformer lies in replacing the slow operation of applying voltages and measuring currents by applying fast radio frequency signals and measuring the reflectance. LC circuits remain appealing bec...

Cancer Research, 2021

Background: Common modalities for breast cancer screening include self-breast examination (SBE) f... more Background: Common modalities for breast cancer screening include self-breast examination (SBE) for detection of palpable lumps as well as Mammography scans for detection of suspicious nodules or masses. While both approaches have low specificity, SBE has lower sensitivity for early stage cancers while mammography is associated with radiation exposure risks. A blood-based non-invasive approach for determination of breast cancer risk in asymptomatic individuals can facilitate early detection and improve prognosis and survival. Circulating Ensembles of Tumor Associated Cells (C-ETACs) are heterotypic clusters of malignant cells which originate in a tumor and are ubiquitously detected in peripheral blood of individuals with solid organ cancers. We present findings from two large-cohort prospective observational studies showing the suitability of C-ETACs for non-invasive, non-radiological screening for breast cancer. Methods: 15 ml of peripheral blood was collected from 14,962 female vo...

Journal of emerging technologies and innovative research, 2018

Saadat Hasan Manto’s short-stories are characterized by his unapologetic brave voice, and in that... more Saadat Hasan Manto’s short-stories are characterized by his unapologetic brave voice, and in that they are empowering. They are populated by women characters, often sex-workers who despite their victimization and marginalization strive to make a living and try and make sense of their scattered realities. However, are these women from his stories only helpless victims, as we have come to see them in popular opinion, or do they also, at times as a result of their marginalization, exercise an agency? Research on his short-stories has had as its centre of focus their importance as partition narratives within the domains of sex, sexuality and gendered violence. Although there have been extensive feminist readings of his works, they have only managed to see the female in his works as a permanent victim, with no agency or influence whatsoever. Contrary to these opinions, some of his characters do exercise an agency to influence the lives of others or at times to create a self-identity, as ...

Day 2 Wed, October 17, 2018, 2018

Raageshwari Deep Gas field situated in southern Barmer Basin of India is a retrograde gas condens... more Raageshwari Deep Gas field situated in southern Barmer Basin of India is a retrograde gas condensate volcanic reservoir. More than 150 fracturing treatments have been pumped in this reservoir to achieve sustained economical production. The paper describes the results of a statistical analysis done to find correlations between production data and fracturing design parameters including petrophysical and geo-mechanical properties of the rock, pre-frac diagnostic tests, and fracturing treatment data including both pumping data and pressure matched parameters. This paper uses the data from multiple production logs to generate stage wise Productivity Index (PI). This PI data was then cross plotted against various parameters and combinations of parameters such as In-situ proppant concentration, formation porosity, net pay, average stress, proppant mass pumped per stage, fracturing fluid recovery rate and percentage, and fracture dimensions. One interesting line of investigation looked at t...

We report measurements of electron-spin-echo envelope modulation (ESEEM) performed at millikelvin... more We report measurements of electron-spin-echo envelope modulation (ESEEM) performed at millikelvin temperatures in a custom-built high-sensitivity spectrometer based on superconducting micro-resonators. The high quality factor and small mode volume (down to 0.2 pL) of the resonator allow us to probe a small number of spins, down to 5 × 10 2. We measure two-pulse ESEEM on two systems: erbium ions coupled to 183 W nuclei in a natural-abundance CaWO 4 crystal and bismuth donors coupled to residual 29 Si nuclei in a silicon substrate that was isotopically enriched in the 28 Si isotope. We also measure three-and five-pulse ESEEM for the bismuth donors in silicon. Quantitative agreement is obtained for both the hyperfine coupling strength of proximal nuclei and the nuclear-spin concentration.

Neuro-Oncology, 2020

The diagnosis of Central Nervous System (CNS) malignancies such as Gliomas in individuals present... more The diagnosis of Central Nervous System (CNS) malignancies such as Gliomas in individuals presenting with Intracranial Space Occupying Lesions (ICSOL) is based on histopathological examination (HPE) of tumor tissue obtained by an invasive brain biopsy. However, brain biopsies are resource intensive and are associated with procedural risks such as haemorrhage, morbidity and mortality. The present study evaluated a non-invasive approach for diagnosis of CNS-M in symptomatic individuals based on evaluation of circulating tumor analytes in peripheral blood. The non-invasive multi-platform approach for diagnosis of CNS-M included Immunocytochemistry (ICC) profiling and Fluorescence in situ Hybridization (FISH) of Circulating Tumor Cells (CTCs) and Digital Droplet PCR (ddPCR) of cell-free tumor DNA (ctDNA) and exosomal mRNA. Performance characteristics of each platform were evaluated using blood and tissue samples from 445 individuals including 227 known cases of CNS-M, 47 known cases of ...

Journal of Magnetic Resonance, 2019

In high sensitivity inductive electron spin resonance spectroscopy, superconducting microwave res... more In high sensitivity inductive electron spin resonance spectroscopy, superconducting microwave resonators with large quality factors are employed. While they enhance the sensitivity, they also distort considerably the shape of the applied rectangular microwave control pulses, which limits the degree of control over the spin ensemble. Here, we employ shaped microwave pulses compensating the signal distortion to drive the spins faster than the resonator bandwidth. This translates into a shorter echo, with enhanced signal-to-noise ratio. The shaped pulses are also useful to minimize the dead-time of our spectrometer, which allows to reduce the wait time between successive drive pulses.

SPE Oil and Gas India Conference and Exhibition, 2019

The Raageshwari Deep Gas (RDG) field, situated within Barmer Basin in the State of Rajasthan, Ind... more The Raageshwari Deep Gas (RDG) field, situated within Barmer Basin in the State of Rajasthan, India, was discovered in 2003. The field is a tight gas condensate reservoir, with excellent gas quality of approximately 80% methane, low CO2 and no H2S. Since the permeability (0.01 - 1 md) is low in this reservoir, hydraulic fracturing is required to get substantial recovery from the wells. The field has been under production since 2010. The development of this field has been carried out in three phases and more than 150 fracturing treatments have been pumped in this reservoir till date to achieve sustained economical production. This paper deals with the lessons learnt and changes implemented in choke design through various development phases of the field. In the initial phase of field development, chokes with a low Flow Coefficient (Cv) were installed to meet the requirement of controlling the wells at low flow rates and high differential pressure. Later as the surface handling capacit...

Physical Review Applied, 2017

Accessing intrinsic properties of a graphene device can be hindered by the influence of contact e... more Accessing intrinsic properties of a graphene device can be hindered by the influence of contact electrodes. Here, we capacitively couple graphene devices to superconducting resonant circuits and observe clear changes in the resonance-frequency and-widths originating from the internal charge dynamics of graphene. This allows us to extract the density of states and charge relaxation resistance in graphene p-n junctions without the need of electrical contacts. The presented characterizations pave a fast, sensitive and non-invasive measurement of graphene nanocircuits.

Day 3 Thu, January 26, 2017, 2017

Objective This paper summarizes key engineering discoveries and technical findings observed durin... more Objective This paper summarizes key engineering discoveries and technical findings observed during the staged development of a volcanic reservoir. Through out the development, 200 hydraulic fracturing diagnostic injection tests and 168 hydraulic fracturing treatments were performed. This program was conducted in one of the few commercially viable thick and laminated volcanic gas reservoirs in the world and were staggered in 5 separate campaigns over an 11-year period. Method, Procedure, Process Due to the low permeability of this gas reservoir, hydraulic fracturing was necessary for sustained economic productivity. As this massive laminated reservoir contained between 15 to 40 vertically separated pay sections, a key design consideration was to connect as much pay as possible with the least number of fracturing stages. Although a conventional plug and perforation frac technique gives full assurance of optimal fractures for every bit of pay, the completion cost would undermine the pr...

Day 1 Mon, November 14, 2016, 2016

Cairn India Ltd & ONGC completed a joint venture appraisal of the Barmer Hill (BH) field in the R... more Cairn India Ltd & ONGC completed a joint venture appraisal of the Barmer Hill (BH) field in the Rajasthan block of India in 2015. The objective was to evaluate the effectiveness of horizontal multi-frac completions. The Barmer hill field is a moderate permeability (0.5 – 4 mD) oil bearing porcellanite with alternating sequences of tight shale. To produce this reservoir economically, hydraulic fracturing was the obvious choice of stimulation and was performed on a number of vertical wells (see Shaoul et al. 2007). To better evaluate the development strategy, completions using either transverse or longitudinal fracture treatments were successfully designed, executed, and evaluated. In the appraisal phase, four vertical and four horizontal wells were drilled to appraise the Barmer Hill reservoir in the Mangala field. Two of the horizontal wells were drilled along the maximum horizontal stress direction and completed with multiple hydraulic fracturing stages, which generated longitudina...

Abu Dhabi International Petroleum Exhibition & Conference, 2016

The Raageshwari Deep Gas (RDG) field in Barmer Basin was discovered in 2003 by Cairn India. The R... more The Raageshwari Deep Gas (RDG) field in Barmer Basin was discovered in 2003 by Cairn India. The RDG field has excellent gas quality with low CO2 and no H2S. The average well depth is 3300m with bottomhole pressure of 5500 psi and bottomhole temperature of 123degC – 135 degC. Typical gas production rate is up to 12 MMSCFD with CGR of 50-60 bbl/MMSCF during initial well testing. The field is developed with 3.5" monobore vertical wells suitable for multistage hydraulic fracturing. Hydraulic fracturing treatment is required as thin laminated volcanic comprise most of the reservoir section having permeability of ~ 0.1 mD. Till date, Cairn India the operator has undertaken four hydraulic fracturing campaigns in Raageshwari gas field with over 100 successful fracs pumped in 25 wells. One of the critical components that lead to a successful hydro fracturing job is fracturing fluid. The properties of the fracturing fluid impact the fracture geometry, the proppant pack conductivity, and ...

SPE Oil & Gas India Conference and Exhibition, 2015

An appraisal well in the KG Onshore Block (a joint venture of Cairn India Ltd and ONGC) has provi... more An appraisal well in the KG Onshore Block (a joint venture of Cairn India Ltd and ONGC) has provided key engineering and operational learning's. The objective of this well was to appraise two separate low permeability reservoirs (~ 0.1md) which are ~4300m deep and falls under HPHT conditions. Due to their low permeability; hydraulic fracturing was necessary to verify the production potential of these reservoirs. To cater this, the discovery well was re-designed and sidetracked so that it could handle the expected fracturing loads. Hydraulic fractures (~387,000 lbs of Proppant); biggest in terms of proppant placed in any single stage in India, were executed and then the well was completed with slim-hole selective completion in challenging underbalanced conditions to test these reservoirs selectively. This paper primarily talks about the key constraints while planning and designing this well and then deals in detail on the learnings while executing this unique completion operation...