Cycloadditions in mixed aqueous solvents: the role of the water concentration

We examined the kinetics of a series of cycloaddition reactions in mixtures of water with methanol, acetonitrile and poly(ethylene glycol) (MW 1000). The reactions include the Diels–Alder (DA) reaction between cyclopentadiene and N-n-butylmaleimide or acridizinium bromide, the retro-Diels-Alder (RDA) reaction of 1,4,4a,9a-tetrahydro-4a-methyl-(1α,4α,4aα,9aα)-1,4-methaneanthracene-9,10-dione and the 1,3-dipolar cycloaddition of benzonitrile oxide with N-n-butylmaleimide. Plots of logk vs the molar concentration or volume fraction of water are approximately linear, but with a characteristic break around 40 M water. This break, absent for the RDA reaction, is ascribed to hydrophobic effects. Comparison with aqueous mixtures of the more hydrophobic 1-propanol shows that these mixtures induce qualitatively similar effects on the rate, but that preferential solvation effects cause the mixtures of 1-propanol to exhibit a more complex behavior of logk on composition. The results are analyzed using the Abraham–Kamlett–Taft model. The solvent effects in aqueous mixtures are not satisfactorily described by this model. For some cycloadditions, small maxima in rate are observed in highly aqueous mixtures of alcohols. The origin of these maxima and the aforementioned breaks is most likely the same.

Evaluation of Students’ perceptions of library service quality using LibQUAL model: The case study in Hospitality Institute in India

The purpose of this study is to evaluate the hospitality students’ perception of library service quality provided by the institute using a well-known measurement model LibQUAL. A structured questionnaire with 22 items on three dimensions of LibQUAL was distributed to undergraduate (UG) and postgraduate (PG) students using Google forms. The mean differences between the UG and PG were analyzed using independent sample t-test. The findings suggest that there is a significant difference in the mean perception of undergraduate and postgraduate students about the library services provided by the institute. This study provides practical insight to library managers about the perception of services provided. The library administrators need to take note of these differences in the perception and bring the necessary changes in their standard operating procedure to improve the quality of services provided

An empirical study of the overall satisfaction of hospitality students towards library services

Abstract: The purpose of this study is to identify the significant dimension of LibQUAL+ that has a greater influence on hospitality students’ satisfaction towards the quality of the overall service provided by a library. Authors of this study have used a modified (a shorter performance-only) LibQUAL+ tool to measure the perceived service quality of a library. The data for this study is collected from both graduate and post-graduate students from a single hospitality institute in Karnataka, India. The regression analysis is used to test the hypotheses. “Affect of Service” emerged as a significant dimension accounting for hospitality students’ satisfaction. The study gives practical insights to library managers about students’ perceptions of service quality for improved decision-making and helps them to reallocate human resources effectively by identifying the most important predictor of library service quality

Machine learning-based simplified methods using shorter wind measuring masts for the time ahead wind forecasting at higher altitude for wind energy applications

Since wind is a fluctuating resource, the integration of wind energy into the electricity grid necessitates precise wind speed forecasting to maintain grid stability and power quality. Machine learning models built on different algorithms are widely used for wind forecasting. This requires a vast quantity of past wind speed data collected at the hub levels of the wind electric machines employed. Tall met masts pose a variety of practical issues in terms of installation and long-term maintenance, which will grow more challenging as next-generation wind turbines come with larger capacities and higher hub heights. In this paper, we propose four non-conventional methods for the time ahead forecasting of wind speed at a higher height by utilizing the wind speed data collected with relatively shorter wind measuring masts. We employ machine learning-based models and rely on the principle of interrelation between wind speeds at different altitudes in our investigations. Wind speed forecasts generated by the new methods at an altitude of 80 m above the ground level using wind speed data measured at lower altitudes of 50 m and 20 m are of industrially acceptable accuracy. The simplified physical requirements such methods demand far outweigh the marginal fall in prediction accuracy observed with these methods.Since wind is a fluctuating resource, the integration of wind energy into the electricity grid necessitates precise wind speed forecasting to maintain grid stability and power quality. Machine learning models built on different algorithms are widely used for wind forecasting. This requires a vast quantity of past wind speed data collected at the hub levels of the wind electric machines employed. Tall met masts pose a variety of practical issues in terms of installation and long-term maintenance, which will grow more challenging as next-generation wind turbines come with larger capacities and higher hub heights. In this paper, we propose four non-conventional methods for the time ahead forecasting of wind speed at a higher height by utilizing the wind speed data collected with relatively shorter wind measuring masts. We employ machine learning-based models and rely on the principle of interrelation between wind speeds at different altitudes in our investigations. Wind speed forecasts generated by the new methods at an altitude of 80 m above the ground level using wind speed data measured at lower altitudes of 50 m and 20 m are of industrially acceptable accuracy. The simplified physical requirements such methods demand far outweigh the marginal fall in prediction accuracy observed with these methods

The Centrality of Religious Festival Experience and Satisfaction on The Subjective Well-Being of Visitors: Evidence from Udupi Paryaya Festival

Themed public celebrations, known as festivals, that explore and promote different aspects of local culture contribute significantly to the economic and social well-being of regions. They provide a distinctive image to the place and create a unique, shared, and memorable experience (ME) for visitors. In India, large-scale festivals represent a source of social interaction that generates positive socio-cultural, hedonic, and functional benefits, which are believed to increase happiness and, subsequently, subjective well-being. This paper explores the religious essence of the historic sacred religious site in Udupi, Krishna Matha. To do so, it examines visitors’ ME from attending a unique biennial religio-cultural festival known as Paryaya. The quantitative study investigates the impact of ME on subjective well-being (SWB) and the mediating role of satisfaction on this relationship. The study results show that ME has a significant influence on satisfaction and SWB. This study is one of the first in the indigenous tourism literature to test a framework that characterises the relationship between ME, satisfaction, and SWB of visitors in a religious festival setting. It provides a new perspective from which festival organisers and tourism policymakers at the local and state government levels can respond to visitors’ needs and plan for the sustainability of such mega-events. Locally, organisers and managers of Krishna Matha may focus on continuing their profile-raising outreach efforts on behalf of the location

Commensal Gut Bacteria Regulate Paneth Cell Function Putatively Via Signaling Through the Sub-Epithelial Tissue

Crohn’s Disease (CD) is an inflammatory disorder of the intestines caused by a dysregulated immune response to resident gut bacteria. Presently, most treatments for CD suppress the host immune system, which can lead to adverse side effects such as increased susceptibility to infections and malignancy. Hence, low-risk alternative treatment options are needed. Studies suggest that defects in Paneth cells (PCs) contribute to CD pathogenesis. PCs are specialized intestinal epithelial cells that regulate the gut microbiota through the secretion of antimicrobial peptides (AMPs). However, the reciprocal impact of the gut microbiota, as well as the role of the underlying intestinal stroma on PC function is still unclear.Bachelor of Art

Long-term TNT and DNT contamination: 1-D modeling of natural attenuation in the vadose zone: case study, Portugal

The vadose zone of a trinitrotoluene (TNT) and dinitrotoluene (DNT) contaminated site was investigated to assess the mobility of those explosives under natural conditions. Located in the left margin of the River Tejo Basin, Portugal, the site is located on unconsolidated sediments. Wastewaters associated with the 50-year explosives production were disposed in excavated ponds, from where water would infiltrate and pollute the unsaturated and saturated parts of the local aquifers. Two boreholes were drilled to 9 m depth in such a former waste pond to investigate the contaminant's fate in the vadose zone. Sediment samples were taken every 1-2 m for analysis of the polynitroaromatics (p-NACs) and organic volatile compounds, pH, organic carbon content, cation exchange capacity and grain size analysis. The main contaminant was TNT representing >70 % of the total p-NACs concentration that peaked approximately 7 mg/kg in one borehole, even if the median in both boreholes was of similar to 1 mg/kg. DNT was 4-30 % of the total p-NACs and nitrotoluene (NT), up to 5 %. No other (volatile) organic compound was detected. The predominance of TNT as the main contaminant implies that any natural mass reduction has been inefficient to clean the site. Several 1-D model simulations of p-NACs cleaning of the vadose zone under natural conditions indicated that the most probable scenario of combined advection and partitioning will only remove TNT after 10's of years, whereas DNT and NT will hardly be removed. Such low concentrations and long times for the p-NACs removal, suggest that by now those compounds have been washed-out to a level below standard limits

Synthesis and characterization of ZEin-based Low Density Porous Absorbent (ZELDA) for oil spill recovery

Removal of spilled petroleum oil from water bodies using hydrophobic porous absorbent has garnered considerable attention due to the simplicity, large-scale adaptability and robustness of the process. However, the use of nonbiodegradable synthetic oil absorbent during cleanup has raised a secondary concern such as generating plastic pollutants that can accumulate in marine and other ecosystems. To encounter this potential hazard, there is a need to find new biocompatible alternatives to currently used non-degradable porous materials. Here we present ZEin-based Low Density porous Absorbent (ZELDA) synthesized from an emulsion templating method as a new class of naturally derived porous material with tunable hydrophobicity for oil spill recovery. Corn-derived zein nanoparticles are first used to form oil-in-water Pickering emulsion. The addition of polymeric zein into the continuous aqueous phase of the emulsion, and its gradual phase separation enables the formation of a porous matrix. The pore diameter, surface wettability, and oil uptake capacity of ZELDA can be programmed by tuning oil-to-water phase volume ratio of the Pickering emulsion and its selective surface functionalization using flaxseed oil. The synthesis of ZELDA can be further modified with iron oxide nanoparticles to induce magnetic response, which enables its contactless maneuverability and removal from spilled site. The study outlines a new method of synthesis of zein-based porous materials and introduces synthetic routes for controlled surface functionalization, wettability, and stimuli responsiveness of the porous material. The synthesized plant-based material provides an ecofriendly alternative to commercially used nonbiodegradable oil sorbents for spilled oil remediation