This paper discusses about the design and analysis of a novel multi-cavity tubular receiver developed for small- and medium-scale concentrated solar power applications from the existing basic baffle-plated volumetric receiver model which is used in large-scale applications. The design and analysis work has been completed to enhance the thermal performance of cavity receivers for the average solar power input of 12 kW with a dish concentrator of 15 m² aperture area. This was carried out by replacing the baffle plates from the conventional basic volumetric receiver with multi-cavity tubes, keeping the heat transfer area as constant. The tubular arrangement improves the flow and heat transfer characteristics through minimized pressure drop. The receiver models with aluminum, copper, and silicon carbide materials have been analyzed using commercially available CFD software ANSYS-FLUENT for different flow rates of air and water. The computational analysis reveals that the thermal performance of a modified multi-cavity tubular receiver model made up of SiC material is better than receiver model with aluminum and copper materials. The maximum energy efficiency of 21.11% and 75.81% are achieved by the heat transfer fluids air and water, respectively. The maximum efficiency is achieved at the flow rate of 1.35 l/min and 0.9 l/min for the heat transfer fluids air and water, respectively. The study concludes that the multi-cavity tubular configurations may be well suited for small-scale CSP applications than the volumetric receivers with foams, rods, honeycomb, and baffle-plated structures.

A temperature control curtain can effectively mitigate the negative effect of outflow temperature on the river eco-environment downstream. To investigate the response of outflow temperature to influence factors (i.e., installation position of temperature control curtain, submerged depth, temperature distribution, and outflow discharge), experiments were conducted in a nonlinearly stratified fluid. The important degree of influence factors was determined by entropy weight method. The results indicated that the effect extent of influence factors on the outflow temperature was temperature distribution, submerged depth, outflow discharge, and installation position in turn. The installation position had little effect on the outflow temperature. Increasing the outflow discharge could withdraw more warm water near the surface and increase the outflow temperature. The outflow temperature also rose with decreasing submerged depth, and more warm water above the temperature control curtain level tended to be extracted when the submerged depth was enough. Although the outflow temperature increased, its variation amplitude depended on the temperature gradient of temperature distribution and was not affected by the structural form of selective withdrawal. From the point of operation management, the minimum submerged depth was determined using sensitivity analysis to obtain maximum improvement of outflow temperature.

Achieving the win-win goal of economic development and carbon intensity reduction, especially through industrial restructuring, is a challenge involving uncertainty and complexity. Determining which industry is green and whether it should be encouraged or limited at different stages of economic development are key issues. The relationship between industrial structure and carbon intensity was systematically analyzed in 21 industrial sectors from 1971 to 2014 in eight developed countries, with different levels of economic development, using an extended dynamic threshold model. The results indicated that there is a relationship between industrial composition and carbon intensity, and the impact trajectory of industrial structure on carbon intensity can be classified into four categories: contaminated, pollution-clean, cleaning hysteresis, and enhanced cleaning. Each type of sectoral relationship between GDP and carbon intensity would change at certain economic levels. The change points for most sectors were US$ 525 and US$ 3904 GDP per capita, which represent the points at which a country enters the mid-industrialization and high-tech industrialization stages, respectively. Therefore, the government and enterprises must upgrade their industrial structure as the national GDP increases, adjust the proportion of sectors operating according to the industrial characteristics, and improve production technology through environmental regulation.

This study was conducted to evaluate the effect of chitosan nanoparticles (CNPs) isolated from Artemia salina against hepatocellular carcinoma (HCC) both in vitro (HepG2) and in vivo (diethylnitrosamine-induced HCC in rats) and to investigate the involved underlying mechanisms. Administration of CNPs decreased HCC progression as evidenced by (1) induced HepG2 cell death as detected by MTT assay; (2) induced necrosis as indicated by acridine orange/propidium iodide (AO/PI) red staining, annexin V/7-AAD positive staining (detected by flow cytometry), and upregulated expression of necrosis markers (PARP1 and its downstream target, RIP1 genes), but no effect on apoptosis as revealed by insignificant changes in caspase 3 activity and mRNA levels of Bax and AIF; (3) increased intracellular ROS and decreased mitochondrial membrane potential in HepG2; (4) decreased liver relative weight, serum levels of liver enzymes (ALT, AST, and ALP), total bilirubin, and cancer markers (AFP and GGT), number and area of GST-P positive tumor nodules; and (5) reduced oxidative stress (decrease in MDA levels) and increased activities of SOD, CAT, and GPx enzymes in rat liver. The preventive (pre-treatment) effect of CNPs was better than the therapeutic (post-treatment) effect. Collectively, administration of CNPs inhibited HCC progression in vitro and in vivo, possibly through induction of necrosis, rather than apoptosis, and induction of antioxidant enzyme activities in vivo, but with stimulation of ROS production in vitro. Thus, CNPs could be used as a promise agent for treating HCC after application of further confirmatory clinical trials.

Ternary amino-functionalized magnetic illite-smectite (AMNI/S) nanocomposites were prepared via integrating two-dimensional illite-smectite nanoflakes (NI/S), magnetite nanoparticles (Fe₃O₄), and 3-aminopropyltriethoxysilane (APTES). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The results show that Fe₃O₄ nanoparticles can be well dispersed on NI/S flakes and the hydrolyzed APTES molecules can simultaneously bond to the hydroxyl groups of Fe₃O₄ and NI/S. Due to the synergetic effect, magnetic NI/S composite can graft more amount of APTES molecules rather than Fe₃O₄ nanoparticles or NI/S alone. When the mass ratio of NI/S:Fe₃O₄ is 1:1, the saturation magnetization of AMNI/S-1 is 17.4 emu/g, facilitating the efficient magnetic separation in aqueous solution. Also, AMNI/S-1 shows a maximal adsorption amount of Pb(II) ions of 227.8 mg/g calculated by the Langmuir model. The effects of initial concentration of Pb(II) ions, pH value, adsorption time, and temperature on the adsorption amount of Pb(II) ions were investigated. The adsorption kinetic models and isotherm models were applied to analyze the adsorption of Pb(II) ions, respectively. The thermodynamic analysis reveals that the adsorption of Pb(II) onto AMNI/S-1 is spontaneous and endothermic in nature. The mechanism for the adsorption of Pb(II) ions onto AMNI/S-1 is due to the surface complexation of Fe₃O₄ and NI/S, and the chelation of amine groups (–NH₂). AMNI/S-1 can be efficiently reused and the regenerated AMNI/S-1 remains 82.91% of initial adsorption capacity after 6-cycle adsorption/desorption process. Thus, ternary AMNI/S-1 could be used as a prospective effective adsorbent.

The purpose of this study is to investigate the relationship between official development assistance (ODA) on CO₂ emissions based on both direct and indirect frameworks, using the annual panel data of 30 recipient countries of Korea from 1993 to 2017. It employs a modified impact, population, affluence, and technology (IPAT) model and a simultaneous equation framework for the direct model and indirect model, respectively. The empirical results suggest that ODA has both a direct and an indirect mitigation impact in the recipient countries. Compared to the direct impact, a small indirect mitigation impact of ODA on CO₂ emissions is derived. However, the estimation results of the environmental Kuznets curve (EKC) equation imply that economic growth has the potential of mitigating the environmental degradation when the economic development in recipient countries of Korea reaches a certain level. Therefore, the bilateral cooperation, through ODA and the supportive policy, should make an effort to promote economic development and mitigation of environmental degradation in developing countries.

The hydrogeological and hydrogeochemical data of 75 groundwater samples and Landsat 8 OLI satellite data were used to identify the source and mechanism of groundwater and soil salinization in Femenin-Ghahavand aquifer (FGA) in Hamadan area, Iran. Generally, the EC values range from 350 to 7556 μS/cm with a mean value of 1785 μS/cm. The salinity value increases in the groundwater along the flow direction from southeast to northwest. The water samples are categorized into two water types of HCO₃–Ca and Ca²⁺–Mg²⁺–Cl⁻. The water samples are super-saturated with calcite and dolomite due to dissolution of carbonate rocks through the flow path from recharge to discharge zones and under-saturated with respect to gypsum and halite. The most probable source of salinity is dissolution of interlayer of halite and gypsum in Miocene Marl and Qom formation in the bedrock of FGA. Also, the ion exchange is another major process that affects the deep groundwater quality in FGA. The water samples of FGA were divided into two groups based on the HFE diagram. About 71% of the samples are plotted below the mixing line, indicating intrusion process with reverse ion exchange and the rest (29%) is under freshening process with direct ion exchange. Consequently, the source of salinity in FGA groundwater is dissolution of halite and gypsum in deep saline groundwater which is likely upconing and mixing with fresh groundwater during overexploitation. The result of soil investigation using NDS index based on Landsat 8 OLI satellite data shows severe increase in salinization from 2013 to 2019. The areas with saline groundwater have saline soil too, indicating same source of groundwater and soil salinization. However, the main cause of soil salinization would be land use change and irrigation by saline groundwater and high evaporation in the region.

Cigarette smoke is a known risk factor for urothelial carcinoma (UC). However, there is limited information about the distributions and effects of volatile organic compounds (VOCs) on smoking-related UC risk. With this hospital-based case-control study, we explored the associations between urinary levels of cotinine and VOC metabolites (acrylamide, 1,3-butadiene, and benzene) and the risk of UC. Urological examinations and pathological verifications were used to confirm the diagnoses of UC. All study participants provided smoking-related information via questionnaires and face-to-face interviews; they also provided urine samples for the measurement of VOC metabolites, cotinine, and 8-hydroxydeoxyguanosine (8-OHdG), which was used as an indicator of oxidative stress. We applied multiple logistic regression analysis to estimate the risk of UC, and we found that levels of urinary cotinine and 8-OHdG were higher in the UC group than in the control group. Furthermore, urinary levels of VOC metabolites, including N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA), N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine, N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine-3, trans,trans-muconic acid (t,t-MA), and S-phenylmercapturic acid (SPMA), increased with increasing levels of urinary cotinine. After adjusting for potential risk factors, dose–response relationships were observed between UC risk and urinary levels of AAMA, t,t-MA, SPMA, and 8-OHdG. Participants with high urinary levels of cotinine, AAMA, t,t-MA, SPMA, and 8-OHdG had risks of UC that were 3.5- to 6-fold higher than those of participants with lower levels. Future, large-scale investigations of the risks of UC should be explored, and repeated measurement of VOC metabolites should be assessed.

The Gippsland Lakes estuary, a Ramsar listed wetland, in Victoria, Australia, is an area of potential concern for metal pollution due to influxes of human population and associated anthropogenic activities. A biomonitoring exercise was undertaken where the concentrations of 9 metals (Cr, Fe, Cu, Zn, As, Se, Ag, Cd and Hg) were analysed in the soft tissue of two common sessile invertebrates: the mussel Mytilus edulis and the barnacle Amphibalanus variegatus from 6 locations on two different occasions throughout the Gippsland Lakes estuary. A salinity gradient exists in the Lakes, from seawater at Lakes Entrance in the east, decreasing down to < 10 PSU in the west at Lake Wellington during times of rainfall, which is a major factor governing the growth and distribution of both species. Dissolved metal levels in general were low; however, Cu at most sites exceeded the 90% trigger values, while all Zn concentrations exceeded the lowest 80% trigger values of the ANZECC marine water quality guidelines for environmental health. Elevated levels of Cu and Zn were found particularly in barnacles at some sites with environmental contamination due to leaching from anti fouling paints and sacrificial zinc anodes. Elevated levels of Ag and Cd were found in mussels at the Hollands Landing site, which is immediately adjacent to a boat ramp, and Cd and Ag at this site are suspected to originate from inland anthropogenic sources. Concentrations of As in M. edulis across all 6 sites in both sampling periods had mean wet weight As concentrations exceeding the maximum level stated in the FSANZ guidelines. A. variegatus contained elevated levels of Hg especially at the North Arm site with a maximum of 13.6 μg Hg/g dry wt., while A. variegatus also showed temporal changes in Hg concentrations across sites. The maximum Hg concentration found in Mytilus edulis was 1.49 μg Hg/g dry wt. at the Hollands Landing site. Previous contaminant studies of biota in the Lakes have targeted sampling of singular predatory or migratory species, such as Black Bream (Acanthopagrus butcheri) and the Burrunan dolphin (Tursiops australis). This is the first biomonitoring study conducted on sessile organisms to assess metal contamination in the system.

The use of smart materials, especially the carbon-based nanomaterials, is increasing each day. Among the several carbon-based nanomaterials, graphene quantum dots are one of the most impressive ones, not only by its quantum behavior but due to the adsorption quality conferred by electrostatic interactions from the negatively charged groups as the huge surface area (2.630 m2/g). In this study, we developed and tested graphene quantum dots (GQDs) as smart nano-adsorbents of uranium (²³⁸U) from the radioactive industry waste. The GQDs were developed in a size range of 160–220 nm using a totally green route. The results showed that the GQDs were capable to adsorb almost 40% of the uranium (²³⁸U) in alamine 3366 solution. Also, the results demonstrated that using GQDs treatment-like smart nanomaterials for radioactive waste in a volume reduction of almost 90% is achieved, helping the storage process as the final disposal of this material. We may conclude that GQDs may represent a smart device for the treatment of radioactive waste as an alternative of absorbent in the radioactive industry.