Effect of structural properties of acid dyes on their adsorption behaviour from aqueous solutions by amine modified silica

Monoamine modified silica particles (MAMS) were prepared and characterized by infrared (FT-IR) and thermogravimetric analysis (TGA). The modified silica particles were used for removal of acid orange 10 (AO-10) and acid orange 12 (AO-12) from their aqueous solutions. The adsorption behaviour of the two dyes was studied at different experimental conditions of pH, contact time, concentration of dye, temperature and salt solution. The adsorption of AO-10 followed pseudo-first order kinetics whereas AO-12 followed pseudo-second order. The two dyes showed different modes of interaction with silica surface. Desorption of the loaded dyes was carried out at pH 10 and found to be 10.4 and 91.6% for AO-12 and AO-10, respectively.     

Reducing current and future risks: Using climate change scenarios to test an agricultural conservation framework

Evaluating the potential effects of changes in climate on conservation practices can help inform strategies to protect freshwater biodiversity that are robust, even as conditions change. Here we apply a climate change “test” to a framework for estimating the amount of agricultural conservation practices needed to achieve desired fish conservation outcomes for four watersheds in the Saginaw Bay region of Michigan, USA. We developed three climate scenarios from global climate model outputs (high emissions scenario, “2080s” timeframe) to provide insight on potential impacts of a climate driver that represents a key uncertainty for this management system, the amount and timing of spring and summer precipitation. These scenarios were used as inputs to agricultural watershed models, which produced water quality outputs that we compared to thresholds in fish biodiversity metrics at the subwatershed scale. Our results suggest that impacts of climate change on evaporation rates and other aspects of hydrology will shift the relative importance of key stressors for fish (i.e., sediment loadings vs. nutrient concentrations) across these different watersheds, highlighting the need to design resilient implementation plans and policies. Overall, we found that changes in climate are likely to increase the need for agricultural conservation practices, but that increasing the implementation rate above current levels will likely remain a good investment under current and future climate conditions.     

Tapered ZnO Whiskers: {hkil}-Specific Mosaic Twinning VLS Growth from a Partially Molten Bottom Source

Zn particulates overlaid with wurtzite (W)-type ZnO condensates having nearly orthogonal and facets were found to self-catalyze unusual tapered W-ZnO whiskers upon isothermal atmospheric annealing, i.e., thermal oxidation, at 600 °C. Analytical electron microscopic observations indicated that such whiskers formed tapered slabs having mosaic and twinned domains. The tapered whiskers can be rationalized by an alternative vapor–liquid–solid growth, i.e., {hkil}-specific coalescence twinning growth from the ZnO condensates taking advantage of a partially molten bottom source of Zn and the adsorption of atoms at the whisker tips and ledges under the influence of capillarity effect. The tapered whiskers having strong photoluminescence at 391 nm and with a considerable flexibility could have potential applications.     

Engagement in online health communities: Channel expansion and social exchanges

This paper contributes to the discussion on patient engagement in online health communities (OHCs) by integrating channel expansion and social exchange theories. Using survey data from 348 users of OHC, we examine the impacts of perceived channel richness, social support, and willingness to exchange information on OHC engagement. Results show that the perceived channel richness positively influences OHC engagement. The effect of patients’ willingness to share and seek information on engagement is moderated by health status. Finally, engagement in OHCs enhances self-care efficacy and perceived health outcomes. We propose several theoretical implications for researchers and practical contributions for OHC administrators.     

A comprehensive study of two-phase flow and heat transfer of water/Ag nanofluid in an elliptical curved minichannel

In this research, laminar flow and heat transfer of two-phase water/Ag nanofluid with 0–6% volume fraction of nanoparticles at Re = 150–700 in a curved geometry are simulated using finite volume method. Studied geometry is an elliptical curved minichannel with curvature angle of 180°. Forced and natural flow of two-phase nanofluid is simulated at Gr = 15000, 35000 and 75000. For estimation of nanofluid flow behavior, two-phase mixture method is used. The second-order discretization and SIMPLEC algorithm are used for solving governing equations. The results indicate that the increase of volume fraction of nanoparticles leads to the enhancement of the temperature of central line of flow. The increase of Grashof number(Gr ～75000) has a great effect on reduction of dimensionless temperature in central line of flow. Creation of thermal boundary layer at Re = 500 and after the angle of 30° becomes significant. In low Grashof numbers(Gr ～15000), due to the great effects of temperature gradients close to wall, these regions have significant entropy generation.     

Optimal design of a metal hydride hydrogen storage bed using a helical coil heat exchanger along with a central return tube during the absorption process

Metal-hydride (MH) reactors are one of the most promising approaches for hydrogen storage because of their low operating pressure, high storage volumetric density and high security. However, the heat transfer performance of the MH reactor for high hydrogenation rate is inferior. In this study, the heat transfer and hydrogen absorption process of metal hydride tank performance in Mg₂Ni bed is analyzed numerically using commercial ANSYS-FLUENT software. The MH reactor is considered a cylindrical bed including a helical tube along with a central straight return tube for the cooling fluid. The effects of geometrical parameters including the tube diameter, the pitch size and the coil diameter as well as operational parameters on the heat exchanged and hydrogen absorption reactive time are evaluated comprehensively. The results showed that the helical heat exchanger along with central return tube could effectively improve heat exchanged between the cooling fluid and the metal alloy and reduce the temperature of the bed results in a higher rate of hydrogen absorption. For a proper configuration and geometry of the helical coil heat exchanger with a central return tube, the absorption reaction time is reduced by 24% to reach 90% of the storage capacity. After the optimization study of the geometrical parameters, a system with the heat exchanger tube diameter of 5 mm, coil diameter of 18 mm and the coil pitch value of 10 mm is recommended to have lower hydrogen absorption time and higher hydrogen storage capacity. The presented MH reactor can be applied for improvement of heat exchange and absorption process in industrial MH reactors.     

An Empirical Evaluation of Factors Influencing Patients’ Reactions to the Implementation of Health Information Exchanges (HIEs)

Health Information Exchanges (HIEs) offer the potential to fundamentally transform the healthcare system, yet little is known on what happens if healthcare organizations adopt HIEs but patients refuse to allow their health information to be exchanged electronically among healthcare providers. This work attempts to extend the application of privacy calculus theory in the HIE domain by developing and testing a model centered on the perceived benefits, perceived risks, and their antecedents to predict consumers’ opt-in behavioral intention toward HIEs. We conducted an online survey in the USA using 740 samples. The results demonstrate that the advantages of HIEs compared with the traditional exchange options meaningfully contribute to perceived benefits of HIEs. Moreover, trust in HIE models, the transparency of data exchange, and the degree of control over data access significantly attenuate perceived risks of HIEs. The model proposed by this study can be used as a useful conceptual tool for both researchers and practitioners to examine the complex nature of patients’ reactions to the use of HIEs.     

Automatic seizure detection using a highly adaptive directional time–frequency distribution

Multidimensional Systems and Signal Processing - Electroencephalogram (EEG) signals can be used by a proficient neurologist to detect the presence of seizure activity inside the brain. Automated...     

Hygrothermal deterioration in carbon/epoxy and glass/epoxy composite laminates aged in marine-based environment (degradation mechanism,mechanical and physicochemical properties)

Journal of Materials Science - One of the major challenges in off-shore tidal and wave energy devices is the ageing of these structures in the hostile marine environment, which limits their...