The liquid-vapor interface of an ionic fluid

We investigate the liquid-vapor interface of the restricted primitive model (RPM) for an ionic fluid using a density-functional approximation based on correlation functions of the homogeneous fluid as obtained from the mean-spherical approximation (MSA). In the limit of a homogeneous fluid our approach yields the well-known MSA (energy) equation of state. The ionic interfacial density profiles, which for the RPM are identical for both species, have a shape similar to those of simple atomic fluids in that the decay towards the bulk values is more rapid on the vapor side than on the liquid side. This is the opposite asymmetry of the decay to that found in earlier calculations for the RPM based on a square-gradient theory. The width of the interface is, for a wide range of temperatures, approximately four times the second moment correlation length of the liquid phase. We discuss the magnitude and temperature dependence of the surface tension, and argue that for temperatures near the triple point the ratio of the dimensionless surface tension and critical temperature is much smaller for the RPM than for simple atomic fluids.Comment: 6 postscript figures, submitted to Phys. Rev.

Quasi-periodic x-ray eruptions years after a nearby tidal disruption event

Quasi-periodic eruptions (QPEs) are luminous bursts of soft X-rays from the nuclei of galaxies, repeating on timescales of hours to weeks. The mechanism behind these rare systems is uncertain, but most theories involve accretion disks around supermassive black holes (SMBHs) undergoing instabilities or interacting with a stellar object in a close orbit. It has been suggested that this disk could be created when the SMBH disrupts a passing star implying that many QPEs should be preceded by observable tidal disruption events (TDEs). Two known QPE sources show long-term decays in quiescent luminosity consistent with TDEs and two observed TDEs have exhibited X-ray flares consistent with individual eruptions . TDEs and QPEs also occur preferentially in similar galaxies. However, no confirmed repeating QPEs have been associated with a spectroscopically confirmed TDE or an optical TDE observed at peak brightness. Here we report the detection of nine X-ray QPEs with a mean recurrence time of approximately 48 h from AT2019qiz, a nearby and extensively studied optically selected TDE16. We detect and model the X-ray, ultraviolet (UV) and optical emission from the accretion disk and show that an orbiting body colliding with this disk provides a plausible explanation for the QPEs

ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

Cryogenic frequency generation for scalable control and read-out of qubits

Recent advances in solid-state qubit technology are paving the way to fault-tolerant quantum computing systems. However, qubit technology is limited by qubit coherence time and the scaling of quantum processors is limited by the complexity of coupling quantum systems with a classical electronic infrastructure. Hence, the proposed approach is to use CMOS at cryogenic temperatures, in order to ensure physical proximity to the quantum bits, thus reducing thermal gradients and increasing compactness. In this thesis, several RF circuits designed using commercial CMOS technology have been shown to be working at cryogenic temperatures. Such circuits could be easily interfaced (or integrated, in the future) with a qubit processor. The performance of the circuits is comparable to the state-of-the-art systems, currently used as control units for qubits. Moreover, these circuits have a much smaller form factor and could be made to work inside a dilution refrigerator where the qubits are operational, hence providing the first demonstration of a scalable solution.Electrical Engineering, Mathematics and Computer ScienceQuantum Engineerin

Application of ANN and ANFIS for predicting the ultimate bearing capacity of eccentrically loaded rectangular foundations

Extensive laboratory model tests were conducted on a rectangular embedded foundation resting over homogeneous sand bed and subjected to an eccentric load to determine the ultimate bearing capacity. Tests were conducted for foundations with width-to-length ratios (B/L) of zero (strip case), 0.333, 0.5, and 1. The depth of embedment varies from 0 to 1 B with an increment of 0.5 B; where B is the width of foundation and the eccentricity ratio (e/B) varies from 0 to 0.15 with an increment of 0.05. Based on the laboratory model test results, two different approaches are proposed to determine the ultimate bearing capacity. Firstly, a neural network model is developed to estimate the reduction factor. The reduction factor can be used to estimate the ultimate bearing capacity of an eccentrically loaded foundation from the ultimate bearing capacity of a centrally loaded foundation. A thorough sensitivity analysis was carried out to determine the important parameters affecting the reduction factor. Importance was given to the construction of neural interpretation diagram. Based on this diagram, whether direct or inverse relationships exist between the input and output parameters were determined. Secondly, an adaptive neuro-fuzzy interface system (ANFIS) is used to predict the ultimate bearing capacity. The neuro-fuzzy models combine the transparent, linguistic representation of a fuzzy system with learning ability of artificial neural networks (ANNs). The results from the ANN and ANFIS were compared with the laboratory model test results. It is clearly seen that the performance of the ANFIS model in our study is better than that of the ANN model

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Not AvailableThe studies carried out in past showed that indigenous sources like glauconite, mica and feldspar can release potassium and can be used as alternative to conventional fertilizer. The use microbial inoculants, organic matter application, acidulation and physical modification can be promising options for efficient use of indigenous sources of potassium. This can saves huge amount of revenue on import of conventional fertilizers and subsidy on it. All the study mentioned in the paper are either laboratory or pot study, hence there is need to study the available technologies for use of indigenous sources of potassium in field.Not Availabl

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Not AvailableAcross the world, a major challenge is deteriorating environmental health by increasing growth of industries with the unscientific management of industrial waste. Soil contamination with organic and inorganic pollutant is a major task during the production of healthy food. In the last three decades, the concentration of heavy metals in soil has increased drastically, posing a risk to the whole environment, human, as well as animal health. Soil contamination is a threat to sustainable agricultural development and food security in developing countries. Nowadays protection and preservation of the environment from further deterioration have drawn increasing research attention. In the present context, use of modern and traditional technologies aims to maintain the health of natural resources from contamination at economic feasibility. Another major concern is remediation or minimization of toxic metal entry in the food chain contamination of different ecosystems without affecting their functionality. There is a need to make land resources free from metal contamination for healthy and safe agricultural production, to increase food security, and to maintain land use pattern. Advanced remediation techniques are more focusing on in situ environment-friendly practices. Several organic and inorganic remediation technologies to treat heavy metal-contaminated soils are discussed in this chapter.Not Availabl

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Not AvailableThis article critically reviews the information regarding potassium (K) status of Indian soils based on research conducted since 1929. The patterns and lacunae regarding potassium consumption in India are also mentioned. The role of minerals in potassium availability vis-à-vis forms of potassium is discussed and elucidated with suitable clay mineralogical evi- dences. The article also highlights concepts of potassium availability to plants in Indian shrink-swell soils. Authors have pointed out the inefficacy of the universal method used for assessing plant-available K (1N NH4OAc) in Indian shrink-swell soil, as observed from extensive K response studies. The current practicesof assessing only plant available K arenot adequate to detect native changes in soil potassium. This paradoxical situation necessitates revision and revalidation of the existing potassium fertilizer rec- ommendations, which are being adopted since four decades. A holistic research envisaging soil test crop response and mineralogical studies will help in revising potassium evaluation methods in India,leading to judicious fertilizer application by the farmers.Not Availabl

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Not AvailableConservation agriculture (CA) refers to a set of agricultural practices encompassing minimum mechanical soil disturbance, diversified crop rotation and permanent soil cover with crop residues to mitigate soil erosion and improve soil fertility besides soil functions. The CA aims to conserve, improve and make more efficient use of resources through CA-based technologies. It has many tangible and intangible benefits in terms of reduced cost of production, saving of time, increased yield through timely planting, improved water productivity, adaptation to climate variability, reduced disease and pest incidence through stimulation of biological diversity, reduced environmental footprints and ultimately improvements in soil health. However, weeds are a major biotic interference in CA, posing big defy towards its success unless all the principles are completely followed. Development of post-emergence herbicide and growing herbicide-tolerant crops and also the retention of crop residues as a mulch help in managing weed problems and also improve soil moisture retention. Furthermore, this practice of agriculture improves soil organic carbon content which ultimately leads to an increase in input use efficiency

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