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The physical properties of confined water can differ dramatically from those of bulk water. Hydration water associated with polysaccharides provides a particularly interesting example of confined water, because differences in polysaccharide structure provide different spatially confined environments for water sorption. We have used attenuated total reflection infrared (ATR-IR) spectroscopy to investigate the structure of hydration water in films of three different polysaccharides under controlled relative humidity (RH) conditions. We compare the results obtained for films of highly branched, dendrimer-like phytoglycogen nanoparticles to those obtained for two unbranched polysaccharides, hyaluronic acid (HA), and chitosan. We find similarities between the water structuring in the two linear polysaccharides and significant differences for phytoglycogen. In particular, the results suggest that the high degree of branching in phytoglycogen leads to a much more well-ordered water structure (low density, high connectivity network water), indicating the strong influence of chain architecture on the structuring of water. These measurements provide unique insight into the relationship between the structure and hydration of polysaccharides, which is important for understanding and exploiting these sustainable nanomaterials in a wide range of applications.

Experimental investigations were carried out to investigate the effect of thermo-chemical exposures on the hydraulic performance of Compacted Clay Liners (CCLs) in landfills. Hydraulic conductivity of most CCL specimens was increased by two to three times their initial values when exposed to 55 °C for 75 days. CCL specimens also experienced increases in their hydraulic conductivities when exposed to leachate at room temperature. This behaviour could be due to the decrease in viscosity when the permeant was changed from tap water to leachate. However, as the leachate exposure time exceeded the first 15 days, hydraulic conductivity readings decreased to as much as one order of magnitude after 75 days of leachate permeation at room temperature. The gradual decrease in the CCLs hydraulic conductivities was most likely due to chemical precipitation and clogging of pore voids within the soils which seemed to reduce the effective pore volume. The rate of hydraulic conductivity reduction due to leachate permeation was slower at higher temperatures, which was attributed to the lower permeant viscosity and lower clogging occurrence. The observed hydraulic behaviours were correlated to the physical, mineral, and chemical properties of the CCLs and described below.

Summary In this study, a new integrated solar-energy based system for fresh water and electricity production is proposed and thermodynamically analyzed. The proposed system consists of a solar tower with a volumetric solar receiver, a Rankine cycle driven by solar power, molten salt storage subsystem and a multi-stage flash distillation (MFD) subsystem. In the present system, solar tower charges the molten salt, which flows through a heat exchanger to produce steam for the Rankine cycle. A part of the molten salt directly goes to hot storage tank after they are heated up by the solar tower. In order to keep the generated energy at the same level, molten salt in the hot storage tank compensates the deficient energy when direct normal irradiance (DNI) level is not sufficient. After the sunset, only the molten salt from the storage supplies energy to the cycle. The MFD produces the desired amount of fresh water from seawater. The seawater used for the distillation is heated by the saturated steam-water mixture coming from the steam turbine. Utilizing the output fluid as a heat source for the MFD also eliminates the external device for condensation. All system components of the integrated system are analyzed in the Engineering Equation Solver (EES). The overall energy and exergy efficiencies are calculated for each system component. The capacity of the power generation and fresh water production of the proposed system is also calculated. Moreover, a parametric study is undertaken to investigate the effects of varying ambient conditions on the system performance.

In fluidized bed reactors such as Fluid CokersTM, liquid injections are used. Good contact between liquid and bed solids is required to maximize product yields and quality, and gas-atomized nozzles are, therefore, used in all these processes. The spray nozzle technology is known to affect the liquid distribution. Therefore, the objective of this study is to assess the effect on liquid distribution of a draft tube located downstream of the spray nozzle, inside the fluidized bed. Experiments were conducted at a relevant scale, using a commercial-scale nozzle with a liquid flow rate of about 100 L/min in a large-scale pilot fluid bed containing about 7 tonnes of silica sand. Liquid injected into a fluidized bed either forms liquid-solid agglomerates or free moisture, consisting of individual particles coated with a thin layer of liquid. Several electrodes were used to map the free moisture distribution throughout the bed. A draft tube greatly improves the contact efficiency throughout the bed. It also increases the penetration of the gas-liquid jet formed by spray inside the fluidized bed. This article is protected by copyright. All rights reserved

The presence of micropollutants in the environment has triggered research on quantifying and predicting their fate in wastewater treatment plants (WWTPs). Since the removal of micropollutants is highly related to conventional pollutant removal and affected by hydraulics, aeration, biomass composition and solids concentration, the fate of these conventional pollutants and characteristics must be well predicted before tackling models to predict the fate of micropollutants. In light of this, the current paper presents the dynamic modelling of conventional pollutants undergoing activated sludge treatment using a limited set of additional daily composite data besides the routine data collected at a WWTP over one year. Results showed that as a basis for modelling, the removal of micropollutants, the Bürger-Diehl settler model was found to capture the actual effluent total suspended solids (TSS) concentrations more efficiently than the Takács model by explicitly modelling the overflow boundary. Results also demonstrated that particular attention must be given to characterizing incoming TSS to obtain a representative solids balance in the presence of a chemically enhanced primary treatment, which is key to predict the fate of micropollutants.

Summarization: An assessment of the impact of global climate change on the water resources status of the island of Crete, for a range of 24 different scenarios of projected hydro-climatological regime is presented. Three “state of the art” Global Climate Models (GCMs) and an ensemble of Regional Climate Models (RCMs) under emission scenarios B1, A2 and A1B provide future precipitation (P) and temperature (T) estimates that are bias adjusted against observations. The ensemble of RCMs for the A1B scenario project a higher P reduction compared to GCMs projections under A2 and B1 scenarios. Among GCMs model results, the ECHAM model projects a higher P reduction compared to IPSL and CNCM. Water availability for the whole island at basin scale until 2100 is estimated using the SAC-SMA rainfall–runoff model And a set of demand and infrastructure scenarios are adopted to simulate potential water use. While predicted reduction of water availability under the B1 emission scenario can be handled with water demand stabilized at present values and full implementation of planned infrastructure, other scenarios require additional measures and a robust signal of water insufficiency is projected. Despite inherent uncertainties, the quantitative impact of the projected changes on water availability indicates that climate change plays an important role to water use and management in controlling future water status in a Mediterranean island like Crete. The results of the study reinforce the necessity to improve and update local water management planning and adaptation strategies in order to attain future water security. Presented on: Journal of Hydrology

This work is a first attempt to understand the mechanism of metformin thermal decomposition under inert conditions. Thermal gravimetric analysis coupled with mass spectrometry was used to probe the thermal degradation reactions. Density functional theory and second-order perturbation (MP2) theoretical calculations were used to construct a reaction mechanism for metformin decomposition. It was evident that the reactions are initiated via formation of methyl radicals, and ammonia via 1.3-H shift, followed by a series of different secondary reaction pathways. The formation of cyanamide, dimethylamine and HCN were among the main secondary products. The proposed mechanism is important for future treatment of wastewater containing metformin and similar drugs formulations, and their possible conversion to useful commodities.

Abstract The performance of a grooved copper-water thermosyphon with a modest bend between a vertical evaporator section and inclined condenser section was characterized for a moderate fluid loading. The time-averaged temperature varied significantly along the evaporator for heat fluxes up to 10 W/cm2 before becoming more uniform at higher heat fluxes. Transients of the measured temperatures show evidence of different flow regimes that were compared to existing flow pattern maps. The evaporator performance for both the pool region, which had the highest temperature, and the film region were not well predicted for heat fluxes up to 10 W/cm2. The local evaporator performance changed with the change in flow regime, suggesting the need for a flow regime-based performance model. The performance of the condenser appeared to depend on the reduced pressure and was significantly overpredicted by the standard condensation models. A modified model for the condenser was proposed.

Additional file 1: Supplementary Fig. 1. Multivariant principal coordinate analysis (PCoA) plot of the Bray–Curtis similarity matrix of the BCCs of Lake Erie and Lake St. Clair (Top panel) and six different locations (CB, CH, HB, LP, PP and SP) (bottom panel) across 15 months of sampling.

Abstract This study evaluates the feasibility of partially replacing Portland cement in concrete with bottom ash (BA) from municipal solid waste incineration (MSWI). The challenge with this ash lies in its susceptibility to react expansively in alkaline conditions, leading to cracking when used in conventional high-slump concrete. This expansive behavior was confirmed to be the result of the dissolution of the ash’s aluminum metal content and consequent formation of hydrogen gas. The aim of this study was to explore the suitability of BA as a cementitious additive in zero-slump dry-cast concrete instead. The premise was that dry-cast could better diffuse the generated gas and avoid internal pressure build-up. Results from isothermal calorimetry and thermal gravimetric analysis (TGA) clearly correlate enhancements in early-age cement hydration and pozzolanic reactivity. Scanning electron microscope (SEM) images revealed voids channels and larger aggregation formation in the BA applied concrete paste. Dry-cast concrete containing 20% BA replacement of cement exhibited higher strengths than ordinary Portland cement (OPC) reference samples at every test age up to 90 days, with the ultimate strength of BA concrete being 18% higher than that of OPC concrete. The addition of BA also improved resistance to freeze–thaw damage. The study found that MSWI-BA can impart enhancements to dry-cast concrete, qualifying it as a potentially suitable supplementary cementitious material. Use of this otherwise landfilled ash as raw feedstock in concrete-making demonstrates a greener approach to building – scoring favorably in environmental performance for being relevant to resource conservation, landfill diversion, and waste-recycling.