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Structural and dynamical disorder in carbamazepine-oxalic acid cocrystal
No full textThis study explores the structural and dynamic disorder in the nanoporous organic cocrystal carbamazepine-oxalic acid, synthesized via liquid-assisted grinding, using a combination of broadband dielectric spectroscopy and molecular dynamics simulations. Notably, the oxalic acid molecules within the channel-like cocrystalline structure exhibit both translational and rotational dynamic disorder. These oxalic acid molecules are arranged as one-dimensional, interrupted single files within the channels. Their translational motion occurs through small hops, characterized as single-file diffusion at short timescales, transitioning to classical Fickian diffusion over longer times. Rotational dynamics involve jumps between preferred orientations, altering the molecular dipole moments, which are detectable through dielectric relaxation spectroscopy. Despite this disorder, it appears only partial due to hydrogen bonding between the oxalic acid and carbamazepine molecules, which imparts some degree of order within the channels. These findings underscore the value of disordered channel-like cocrystals as model systems for studying dynamics in nanoconfined environments
Thermal performance of jointed plain concrete pavements in urban areas considering shade from buildings
No full textJointed Plain Concrete Pavements (JPCPs) are widely used in India’s highways and urban areas due to their durability and low maintenance requirements. However, their performance is significantly influenced by the development of non-linear temperature distributions caused by environmental conditions. These temperature distributions induce stresses that can lead to fatigue damage and cracking, ultimately reducing pavement service life. While the effects of factors like solar radiation and albedo on JPCP temperatures have been well studied, the role of urban shading, particularly from buildings, remains underexplored. This study investigates the impact of urban shading on the thermal performance of JPCP. A two-part methodology was adopted: (i) a field study on a college campus in Gandhinagar, where pavement surface temperatures were measured across various shading conditions, and (ii) a numerical analysis incorporating prototypical urban geometries based on Local Climate Zones (LCZs), ray-tracing for modelling shadows, and thermal simulations with 30 years of historical weather data. The study was performed for two cities, Chandigarh and Chennai. Temperature distributions were analyzed to compute equivalent linear differences (∆T) and critical eigenstresses (ESRc) in the pavement, which are indicative of curling and self-equilibrating stresses, respectively. The results show that shaded configurations significantly reduce both ∆T and ESRc, improving long-term JPCP performance. This effect was more pronounced in denser urban geometries with taller and more closely spaced buildings, especially during summer months. However, even sparser urban geometries showed improved performance compared to the case without shading. These findings underscore the importance of accounting for urban geometry and shading in JPCP design and performance assessment, particularly in dense settings
How usable is consent withdrawal on the Web? UI requirements and expert evaluation
No full textThe GDPR stipulates that data subjects have the right to withdraw their consent at any time, requiring that it is as easy to withdraw as to give consent. Prior research has studied the usability of consent requests, however, usability of consent withdrawal has received less attention. This ongoing work analyses consent withdrawal from a usability lens using the Privacy Choice Evaluation Framework. An interdisciplinary team of experts (with HCI, CS and legal background) applied this framework to identify usability violations, i.e., potential gaps in the 'ease-of-use' of consent withdrawal interfaces. In future work, we are conducting an expert evaluation of top-200 websites to measure the prevalence of these usability violations, as well as a legal analysis of these usability violations. Based on this analysis, our goal is to propose usable and lawful interface recommendations for consent withdrawal on the web
Climatic Influences on Arsenic Health Risk in the Metamorphic Precambrian Deposits of Sri Lanka: A Re-analysis-based Critical Review
No full textThe present study examines the arsenic associated human health risk in Sri Lanka with due consideration to age and gender vulnerability. While the existing low-grade metamorphic rock carries less possibility of arsenic contamination, the usage of old generation arsenical pesticides may increase the future possibility of a catastrophe. Through a comprehensive Health Risk Index (HRI) it could be seen that the north part of the country carries higher risk for children below eight years of age to develop cancer in long run. Interestingly rainfall pattern correlates with arsenic vulnerable zones, denoting that high monsoon led recharge may prevent rapid anthropogenic fluctuations in anoxic zones thereby preventing vigorous formation of oxy-hydroxides. However, the possibility of sea-water intrusion due to excessive groundwater abstraction may change the major-ion chemistry soon which may impact the co-occurrence scenario of arsenic and fluoride. In this regard the study identifies the wetter regions and their shift from 1981 to 2018 to propose a more stable groundwater regime in terms of sea water intrusion. There exist few scientific literatures concerning the occurrence of arsenic in the groundwater of Sri Lanka but there exists no framework to provide a meaningful interpretation by combining all the available research outputs. The present study therefore provides a basis for understanding the existing groundwater arsenic contamination of Sri Lanka by providing a scientific framework to the studies done so far by various researchers in the past 30 years
CO2 Electroreduction Using Cu-Supported Co3O4 Catalyst for Multielectron Product Formation via Metal–Support Interaction
No full textIn this work, the concept of metal–support interaction to develop an electrocatalyst based on copper/copper oxide is utilized. Cobalt oxide is selected as the oxide support, synthesized by the solution combustion method, upon which copper nanoparticles are dispersed using the formaldehyde reduction method. Different concentrations of Cu (1%, 2.5%, 5%, 10%, and 15%) are loaded over the support, among which the 2.5% Cu/Co3O4 system works the best by giving a Faradaic efficiency of 34%. Detailed catalyst characterizations are performed using X-ray diffractometer, field emission scanning electron microscopy, inductively coupled plasma optical emission spectrometer, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analyses. Electrochemical studies are carried out to estimate the catalyst's activity using techniques such as cyclic voltammetry and chronoamperometry. High-value gaseous (CO, CH4) and liquid product (CH3CH(OH)CH3) are identified during the CO2 electroreduction process. Liquid isopropyl alcohol (IPA) forms at a very low overvoltage (≈200 mV). Pre- and postreaction XRD shows slight shifting of peaks. In XPS, pre- and postspectra reveal complete and partial oxidation of Cu+2/Cu+ and Co3O4, respectively. Electrocatalytic activity of the catalyst is also compared with its precursors (Cu and Co3O4), and the activity of these precursors is much less compared to that of the Cu/Co3O4 system due to metal–support interaction
Influence of pit geometry and flow conditions on sand pit migration in fluvial systems: insights from flume experiments
No full textPit migration can significantly disrupt stable fluvial systems, leading to abrupt changes in river morphology and ecology. This study investigates sand pit migration through lab experiments by varying pit shapes, sizes, and inflow discharge, while using Kinect and a DSLR camera to measure bed profile evolution. Repeatability tests ensure experimental consistency. Observations show that the rate of pit migration increases as the discharge increases. For rectangular pit, the migration rate is highest from 0.212 cm/min to 1 cm/min as the discharge increases from 5.12 litre/s to 6.94 litre/s. The migration rate of parabolic pits is lower than rectangular pits, and cylindrical pits take longer to fill at the centre than the sides. The migration rate of the cylindrical pit increases less (0.36 cm/min to 0.43 cm/min) as compared to the rectangular pit (0.212 cm/min to 1 cm/min). These findings highlight the influence of pit geometry and flow conditions on sediment transport
Computational Study of Propulsive Performance of Frozen Nano-Aluminum and Water (ALICE) Mixtures
No full textA computational study of the propulsive performance of frozen nano-aluminum and water (ALICE) mixtures is conducted. An Eulerian multiphase flow model is developed that accurately captures the dynamics of high-speed multiphase flow in a rocket motor. The particle size is taken to be 80 nm, and the equivalence ratio is 0.71. The governing equations are discretized using the finite volume method and solved computationally using the OpenFOAM computational fluid dynamics library. The evolution of flow, composition, and temperature fields as well as propulsive performance parameters such as thrust, specific impulse, and characteristic velocities are computed. Simulations are conducted for three different rocket motor sizes to study the effect of rocket motor size on propulsive performance. Parametric studies are conducted to probe the effects of incomplete combustion of particles and particle entrainment on the propulsive performance of ALICE propellants. A quasi-1D multiphase equilibrium mixture model is also developed to explain the model predictions as well as to guide the design of numerical experiments. New physical insights on the multiphase flow dynamics in the rocket motor are provided. The model predictions are compared with the experimental data. The likely reasons for the substandard performance of ALICE propellants are identified to be incomplete combustion of particles and inefficient entrainment of particles by the gas flow
Effect of relative compaction on stress-strain response of low-plasticity cohesive oil under drained and undrained monotonic loading conditions
No full textRural to urban migration and discourses of linguistic authenticity in multilingual Nagaland
No full textThis paper looks at how the process of rural-urban migration to multilingual cities has led to diverging language ideologies and new markers of indigenous identity. We discuss two contrasting discourses of authenticity that structure multilingualism based on generational position. Ethnographic fieldwork was conducted in Dimapur, a city in Nagaland, northeast India, a site of high in-migration from the rural hinterlands. Most residents speak various indigenous Tibeto-Burman Naga languages, which are mutually unintelligible. The city, therefore, is characterised by a high degree of multilingualism, where indigenous Naga languages and English, the state's official language, co-exist with Nagamese, an Assamese-based, Indo-Aryan pidgin used in various domains of urban daily life. We find that for many first-generation migrants, for whom language is one of the primary markers of their indigenous identity and tribal homeland, the increasing relevance of Nagamese threatens the dominant discourse of ‘authentic’ indigenous identity that is held up by community elders and institutions such as the church. On the other hand, urban indigenous youth, particularly those raised in Dimapur and more accustomed to the everyday multilingualism of the city, are more ambivalent to Nagamese in relation to their identity