Composite Samples Research Articles

Cost-of-living: the impact on emotional support for young Londoners

Purpose The purpose of this study is to explore the ways in which the cost-of-living crisis affected emotional support access and availability among multiply-marginalised UK-based youth. Design/methodology/approach This study reports findings from early stages of a multiphase youth participatory action research (YPAR) project. In all, 12 young residents of Tower Hamlets London (ages 16–22 years) employed as peer researchers conducted 14 focus groups with 44 residents of Tower Hamlets over a six-month period. Data were analysed using principles of reflective thematic analysis. Findings Analyses produced salient themes that identified barriers to obtaining emotional support from parents and carers, described the utility of diverse support networks and elucidated the impact of the cost-of-living crisis on emotional support and youth well-being. Research limitations/implications This study has several limitations pertaining primarily to study design, sample size and sample composition that limit generalizability of findings. The findings indicate that the cost-of-living crisis markedly constrained the participants’ access to and availability of formal and informal support from others. Practical implications The findings from this research will influence the design and delivery of policy and services to better meet the needs and experiences of UK-based young people and their families. Social implications This project has the potential to increase understanding of how families can provide effective emotional support to young people and so improve the lives of Londoners now and in the future. Originality/value To the best of the authors’ study, this study is the first to use a YPAR approach to exploring the impact of the cost-of-living crisis on UK-based youth.

Assessing the Spatial Distribution, Condition, and Intensity of Soil Acidity for Informed Management Decisions in the Semen Aari District of Ari Zone, Southwestern Ethiopia

Soil acidity poses a significant challenge to agricultural productivity in Ethiopia's highlands, particularly affecting the Semen Ari district in the Ari zone. The common practice of applying agricultural lime to mitigate soil acidity is hampered by a lack of detailed information on the extent, severity, and spatial distribution of acidic soils. This study aims to determine how soil acidity varies spatially by identifying and mapping the specific geographic patterns of soil acidity levels in the Semen Ari district. Seventy-one composite soil samples from the 0–20 cm layer were geo-referenced and analyzed. Using statistical analysis and ArcGIS software for spatial interpolation through ordinary kriging, soil pH ranged from 3.29 to 5.68, classifying 99% of the soils as strongly acidic. The root mean squared error (RMSE) of the interpolation was 0.30. Soil pH showed a significant negative correlation with exchangeable acidity but a non-significant negative correlation with organic carbon and total nitrogen. The results highlight the need for targeted soil management strategies, such as appropriate lime application rates and the cultivation of acid-tolerant crops, to enhance crop yields. Further research is recommended to include comprehensive soil property datasets to better understand the factors influencing soil pH variability, thus supporting more precise management of acidic soils in the region. The generated high-resolution soil acidity map serves as a valuable tool for agricultural planning and decision-making.

Dipodal silane‐treated ramie woven matt reinforced polylactic acid biocomposites for improved mechanical and thermal properties

AbstractHot compression molding was used to produce biocomposites from ramie plain‐woven fabric‐reinforced polylactic acid (PLA). Prior to composite fabrication, alkali and dipodal silane (bis(3‐trimethoxysilylpropyl) amine) (BAS) were applied to improve fiber‐matrix adhesion. Mechanical tests revealed improvements in tensile and flexural strength due to interfacial adhesion. The flexural strength of ramie PLA composite samples treated only with silane (SR‐PLA) was the highest, at 136.35 MPa. Young's modulus was 7.51 GPa. BAS treatment was crucial for ensuring strong adhesion between the fabric and the PLA matrix. In combined alkali‐BAS‐treated composites (ASR‐PLA), the glass transition and crystallization temperatures disappeared completely, affecting PLA morphology. The maximum heat of absorption (373°C) was found in SR‐PLA composites, suggesting electrostatic interactions created a three‐dimensional network. In conclusion, the initial incorporation of dipodal silane resulted in the formation of six silanol linkages with ramie fabric, leading to enhancements in the mechanical and thermal characteristics of ramie–PLA composites.Highlights Alkali and BAS treated Fabrics ironed to remove treatment‐induced wrinkles. Carded PLA fiber with consistent density and weighted in four equal portions. Fabric and PLA lay alternatively in warp direction before compression molding. SR‐PLA composites exhibited improved thermal and mechanical properties.

PERFORMANCE CHARACTERISTICS OF A MODIFIED COMPOSITE MATERIAL CONTAINING INORGANIC LIGHTWEIGHT AGGREGATES

A modified thermal and sound insulation composite material, potentially applicable in the field of modern construction, has been developed. Experimental samples based on foam glass aggregate (made from recycled waste glass), perlite (with fraction size up to 3 mm) and hydraulic binders were obtained. The acoustic and mechanical characteristics and the thermal conductivity coefficient of the prepared series of composite samples were studied. Values for Rw in the range from 38 to 46 dB and for λ from 0.04 to 0.15 W m-1 K-1 were established. The influence of the different components of the composition on the values of the studied performance indicators and the structure of the composite was analysed.

Wear properties of Al6061/SiC + B4C + TiC hybrid composites produced by vacuum infiltration method

Abstract In the study, hybrid metal matrix composite (HMMC) structures were produced by vacuum infiltration method (VIM) using Al6061 alloy and varying amounts of SiC, B4C, and TiC ceramic powder pairs. Age-hardening processes were applied to these HMMCs. After heat treatment, wear behavior was examined under different loads using the pin-on-disc test method. All Al6061 hybrid composites exhibited better wear performance than unreinforced Al6061. In the wear tests of composite samples, the lowest volume loss and therefore the highest wear resistance were obtained in Al6061 3 wt.% B4C + SiC composites under 5 N force. The lowest wear resistance due to the highest volume loss was determined in Al6061/1 wt.% TiC + B4C composites under 15 N force. Abrasive and adhesive wear characteristics were observed in field emission scanning electron microscopy(FESEM) images of worn surfaces. Additionally, wear debris, smearing, and deep grove formations were determined on the surface. In the EDS analysis performed on the worn surface, O and Fe elements were found in addition to the elements that are likely to be in the structure (such as Al, B, C, Ti, Si, and Mg). The wear tests caused the formation of oxide layers on the sample surfaces.

Device-Measured 24-Hour Movement Behaviors and Blood Pressure: A 6-Part Compositional Individual Participant Data Analysis in the ProPASS Consortium.

Blood pressure (BP)-lowering effects of structured exercise are well-established. Effects of 24-hour movement behaviors captured in free-living settings have received less attention. This cross-sectional study investigated associations between a 24-hour behavior composition comprising 6 parts (sleeping, sedentary behavior, standing, slow walking, fast walking, and combined exercise-like activity [eg, running and cycling]) and systolic BP (SBP) and diastolic BP (DBP). Data from thigh-worn accelerometers and BP measurements were collected from 6 cohorts in the Prospective Physical Activity, Sitting and Sleep consortium (ProPASS) (n=14 761; mean±SD, 54.2±9.6 years). Individual participant analysis using compositional data analysis was conducted with adjustments for relevant harmonized covariates. Based on the average sample composition, reallocation plots examined estimated BP reductions through behavioral replacement; the theoretical benefits of optimal (ie, clinically meaningful improvement in SBP [2 mm Hg] or DBP [1 mm Hg]) and minimal (ie, 5-minute reallocation) behavioral replacements were identified. The average 24-hour composition consisted of sleeping (7.13±1.19 hours), sedentary behavior (10.7±1.9 hours), standing (3.2±1.1 hours), slow walking (1.6±0.6 hours), fast walking (1.1±0.5 hours), and exercise-like activity (16.0±16.3 minutes). More time spent exercising or sleeping, relative to other behaviors, was associated with lower BP. An additional 5 minutes of exercise-like activity was associated with estimated reductions of -0.68 mm Hg (95% CI, -0.15, -1.21) SBP and -0.54 mm Hg (95% CI, -0.19, 0.89) DBP. Clinically meaningful improvements in SBP and DBP were estimated after 20 to 27 minutes and 10 to 15 minutes of reallocation of time in other behaviors into additional exercise. Although more time spent being sedentary was adversely associated with SBP and DBP, there was minimal impact of standing or walking. Study findings reiterate the importance of exercise for BP control, suggesting that small additional amounts of exercise are associated with lower BP in a free-living setting.

Exploratory Analysis on the Physical and Microstructural Properties of Aluminum/Fly-Ash Composite

Metal Matrix Composite (MMC) is an innovative material that has the ability to address demands in a number of industries, including mining, automotive, and aerospace. Stir casting is a well-known technique for making MMC. With weight fractions of 10%, 20%, 30%, and 40%, this study aims to analyze the impact of fly ash addition on the physical properties of aluminum (matrix) - FA (reinforcing phase) composites.The test for water absorbent was carried for each samples at 25°C immersed in water at different time interval of 24hrs, 48hrs, 72hrs, and 96hrs. The density test was carried out on the AL/FA composite samples. The water absorption test results showed that at 20wt% of fly ash composite, the optimum water absorption (0.4%) result was obtained at 24hrs, and also at 48hrs for 10wt%. The density of the composites increased with increasing amount of fly ash, and attained optimum of 4.08g/cm3 at 30wt%. The surface morphology of the samples was observed using digital metallurgical microscope. The scope of this study is to determine the physical and morphological properties of Al/FA reinforced composites.

A Monte Carlo Approach for Simulating Electrical Conductivity in Highly Porous Ceramic Composites: Impact of Internal Structure.

Porous ceramic composites play an important role in several applications. This is due to their unique properties resulting from a combination of various materials. Determination of the composite properties and structure is crucial for their further development and optimization. However, composite analysis often requires complex, expensive, and time-demanding experimental work. Mathematical modeling represents an effective tool to substitute experimental approach. The present study employs a Monte Carlo 3D equivalent electronic circuit network model developed to analyze a highly porous composite on the basis of minimum easily obtainable input parameters. Solid oxide cell electrodes were used as a model example, and this study focuses primarily on materials with a porosity of 55% and higher, characterized by deviation of behavior from those of lower void fraction share. This task is approached by adding to the original Monte Carlo model an additional parameter defining the void phase coalescence phenomenon. The enhanced model accurately simulates electrical conductivity for experimental samples of up to 75% porosity. Using sample composition, single-phase properties, and experimentally determined conductivity, this model allows us to estimate data of the internal structure of the material. This approach offers a rapid and cost-effective method to study material microstructure, providing insights into properties, such as electrical conductivity and heat conductivity. The present research thus contributes to advancing predictive capabilities in understanding and optimizing the performance of composite materials with potential in various technological applications.

Intrinsic Chemical Drivers of Organic Aerosol Volatility: From Experimental Insights to Model Predictions

AbstractAccurately predicting the volatilities of molecules in aerosols is challenging but crucial for understanding the atmospheric effects of aerosols. We used negative and positive ion electrospray ionization Fourier‐transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) to identify differences in the molecular compositions of gas and particle phase samples from urban atmosphere. We aimed to identify intrinsic chemical parameters that determine and predict the organic aerosol volatility. We found higher average molecular weights, carbon mass percentages, and double bond equivalents (DBE) but lower average O/C ratios and oxygen mass percentages in the particle phase than the gas phase. We identified DBE, which display a significant negative correlation with volatility, as a key parameter. We proposed to improve the previous model for predicting organic aerosol volatility by incorporating DBE as a new variant; and the result showed that this subsequently improved the accuracy of the model, particularly for compounds with minimal or no heteroatoms (0–2) such as hydrocarbons (CH). The revised model offers insights into the contributions of DBE, carbon, nitrogen, oxygen, and sulfur atoms to the volatilities of diverse organic molecules in aerosols and could be applied to improve our understanding of the phase distributions of volatile organic compounds in the ambient air.

Dengue and chikungunya virus dynamics, identification, and monitoring in wastewater.

Monitoring wastewater is an effective strategy for supporting clinical surveillance for viral infections. Wastewater monitoring, also known as wastewater-based epidemiology (WBE), uses existing wastewater collection networks to obtain a composite sample of a population that can be used to predict disease dynamics in a specific area. Viruses such as dengue and chikungunya are primarily transmitted through the bites of infected Aedes mosquito species. The prevalence of the Aedes mosquito in tropical and subtropical regions makes these diseases a serious threat to public health. Employing wastewater surveillance, monitoring, and regulating the spread of diseases like dengue and chikungunya-notably caused by mosquitoes-has been recommended. However, understanding the dynamics of viral release and its persistence in wastewater is critical for monitoring purposes. Although methods for recovering RNA for some viruses from wastewater have been developed, the same approach does not work equally well for viruses such as dengue and chikungunya due to low levels of viral RNA and susceptibility to degradation. As a result, a tailored approach to recovering these viruses from wastewater is required. This review summarizes viral release from infected hosts, its dynamics, and approaches for dengue and chikungunya wastewater surveillance. The review also identifies existing knowledge gaps in viral persistence in wastewater and recovery.

Investigation on piezoresistive properties of reduced graphene oxide treated glass textiles based multifunctional sensors

AbstractGlass fabric‐reinforced composites (GFRC) and other revolutionary engineered materials find extensive application in the aerospace, construction, and automobile sectors. It is challenging to predict damage under real‐time stresses due to the anisotropic behavior of composite materials. This study presents the development of a glass textile‐based multifunctional composite sensor and demonstrates its application as a change in resistance or gauge factor in structural health monitoring (SHM) systems. This sensor is coated with reduced graphene oxide (rGO) nanomaterial. Its electrical resistance is evaluated by examining the concentration of nanoparticles and varying geometrical parameters. A three‐point bending method assessed the piezoresistive behavior of the integrated sensor in the GFRC. The impact of sensor width and relative placements in the material's thickness direction within the composite samples is evaluated. Cyclic flexural testing was also performed to demonstrate real‐world applications. The research concludes that it can be utilized as a damage assessment technique for GFRC. The developed sensor can be used to provide an electrically conductive path or as a resistor in the field of E‐textiles. The developed piezoresistive sensor has the flexibility to be used as a multifunctional sensor for multiple purposes, such as force, torque, weight, pressure, flow, acceleration sensors, etc.Highlights Glass textile‐based multifunctional materials are reported as strain‐monitoring sensors. Tailored sensor resistance could be achieved through rGO current conduction paths. Glass textile‐based sensors could potentially be used in the field of E‐textile.

Service experience lies in the eye of the beholder: contextualizing extant literature toward integrating eye-tracking in service research

Purpose In spite of offering clear benefits and increased availability, relatively few service research studies rely on eye-tracking. Therefore, this paper aims to assist service researchers in harnessing the vast capabilities of eye-tracking technologies and methods for their own inquiries. Design/methodology/approach In addition to systematically reviewing extant research in the service domain and the wider marketing field with respect to the fundamentals and practices of eye-tracking, this paper presents a concise, empirical eye-tracking demonstration. These contributions suggest future outlooks for how to incorporate eye-tracking more effectively in service research. Findings The systematic literature review informs a comprehensive framework for integrating eye-tracking in service research that comprises research question focus regarding higher-order psychological constructs of interest, appropriate study settings, sample composition, optimal eye-tracking equipment and operationalization considerations. Research limitations/implications By establishing a common ground and recommended uses of eye-tracking for service research, this study equips service scholars with the knowledge they need regarding eye-tracking fundamentals, common practices and future outlooks. A simple, empirical example further demonstrates some options for unlocking the unique capabilities of eye-tracking in service research and uncovering the complexities inherent to service experiences and other core service concepts. Originality/value This paper compiles and contextualizes insights from existing eye-tracking research, which it uses to draw important lessons for deploying eye-tracking in service domains.

Comparative Study of Amino Acids in the Life Stages of Silkworm (Bombyx mori L.)

The silkworm (Bombyx mori L.) undergoes distinct life stages, including egg, larva (caterpillar), pupa (chrysalis), and adult moth(imago), each with specific physiological requirements. Amino acids are essential for the growth and development of the silkworm. In this study, we work in paper chromatography to compare the amino acid profiles in different life stages of the silkworm. Samples were collected from eggs, larvae, pupae, and adult moths. Amino acids were extracted and separated on chromatographic paper using a suitable solvent system. The developed chromatograms were analyzed to determine the relative concentrations of specific amino acids. Our results revealed variations in the amino acid composition across the life stages. The amino acids such as glycine, methionine, leucine, and aspartic acid were common in all life stages of silkworms. These differences may be attributed to the physiological changes associated with metamorphosis and reproduction in adult silkworms. Overall, this study provides valuable insights into the dynamic changes in amino acid profiles during the life stages of silkworms, highlighting the importance of amino acids in their growth, development, and silk production. And, this study demonstrates the utility of paper chromatography as a cost-effective and reliable method for analyzing amino acid composition in complex biological samples, providing valuable insights into the nutritional dynamics of the silkworm lifecycle.

Groundnut (Arachis hypogaea L.) Response to Nitrogen Fertilizer and Earthing Up Practices in the Tigray Region of Ethiopia

To increase groundnut yields, integrated agronomic techniques must be implemented. The current study focuses on using starter nitrogen fertilizer in conjunction with earthing up for groundnut cultivation. Three replications and a factorial combination were used in the complete randomized block design of the experiment. Two types of earthing up (no earthing up and earthing up) and four levels of nitrogen fertilizer (0, 15, 30, and 45 kg ha-1) were used in the treatment combinations. For each of the Hamedo 1 and Hamedo 2 experimental sites, two undisturbed and two disturbed composite soil samples were collected at a depth of 20 cm before sowing. The data analysis showed that neither the combination application of N fertilizer and earthing up nor the individual independent applications of N fertilizer and earthing up had a significant effect on groundnut flowering and maturity. Groundnut plant height, number of branches per plant, number of pods per plant, number of seeds per plant, seed weight per plant, and haulm yields were not significantly affected by earthing up alone or by the co-application of nitrogen fertilizer and earthing up. On the other hand, the exclusive use of nitrogen fertilizer significantly affected groundnut plant height, the number of branches per plant, the number of pods per plant, the number of seeds per plant, seed weight per plant, and haulm yield. Applying 45 kg ha-1 of nitrogen fertilizer to the Hamedo 1 and Hamedo 2 trial sites enhanced the haulm yield by 70.53% and 78.76%, respectively, compared to the unfertilized plots. Individual applications of nitrogen fertilizer, earthing up, or a combination of both had a significant effect on groundnut pod and kernel yields. In comparison to plots that received a combined application of 45 kg ha-1 of nitrogen fertilizer and earthing up, the Hamedo 1 and Hamedo 2 trial sites exhibited increases in pod yields of 57.73% and 55.97%, respectively, when earthing up was combined with 15 kg ha-1 of nitrogen fertilizer. In the same way, applying 15 kg ha-1 of nitrogen fertilizer to the earthing-up soil in the Hamedo 1 and Hamedo 2 experimental sites boosted the kernel yields by 70.05% and 75.43%, respectively, in comparison to soil earthing-up plots that received 45 kg ha-1 nitrogen. The findings of the economic and agronomic analyses showed that applying nitrogen fertilizer and earthing up together greatly increases groundnut yields and revenues. Therefore, to increase groundnut yields and receive more financial advantages, farmers can consider the combined application of 15 kg ha-1 of nitrogen fertilizer and earthing-up.

In vitro antioxidants and anti-inflammatory potentials of high protein-fibre cookies produced from whole wheat, sweet potato, rice bran and peanut composite flour blends

The growing demand for low-cost and functional snacks in many developing nations called for interest in the use of locally grown crops as substitutes for costly imported wheat flour. The amino acid composition, antioxidant and anti-inflammatory properties of the cookies from whole wheat, sweet potato, rice bran and peanut (56.25:18.75:5:20; 37.50:37.50:5:20; 18.75:56.25:5:20% as WPRG 1, WPRG 2, WPRG 3) composite flour blends, respectively, were obtained in this study. The 100% whole wheat and 100% refined flours served as control 1 and 2, respectively. The level of hydrophobic and aromatic amino acids was significantly (p < 0.05) high in WPRG 2 (~ 30 and ~ 10%), respectively when compared to others. However, the branched chain amino acids and Fischer ratio was significantly (p < 0.05) high in WPRG 1 (11.40% and 1.29), respectively, which could have contributed to their improved bioactivities. Notably, the composite cookie samples WPRG 1, 2 and 3 had higher hydroxyl (73.86 − 84.16%), DPPH (76.52 − 84.60%) radical scavenging as well as ferric reducing antioxidant (0.64–0.87 mmolFe2+/mg) properties than the control samples WWF and CWF, respectively. On the contrary, the metal chelating activities of the cookies WPRG 1–3 were not significantly (p > 0.05) different from control samples WWF and CWF. The improved amino acid profile and enhanced antioxidant properties of the composite cookies might have effectively influenced their anti-inflammatory properties (IC50; < 26 μg/ml) when compared to the control samples (IC50; ~ 40 μg/ml), respectively. Hence, the cookies that comprised of antioxidants and anti-inflammatory potentials needed in human health, were acceptable by the consumers.Graphical

Faience beads excavated from Laolongtou cemetery, Yanyuan: new evidence of the cultural exchange between the south‐western and north‐western parts of China

AbstractAncient Chinese beads provide important evidence of cultural exchanges. This study used a scanning electron microscope with an energy‐dispersive spectrometer to analyse the microstructure and chemical composition of faience beads excavated from Laolongtou cemetery in Yanyuan county, China. Based on the analysis results, two glazing methods (efflorescence and cementation) and two bead types (high‐Pb and high‐K beads) were identified. A comparison of the chemical compositions of samples unearthed at the Laolongtou cemetery and samples from north‐western China indicated close regional contact. Bronze wares and burial customs in Laolongtou cemetery also revealed that the Yanyuan region might be a significant node in the Southern Silk Road between the south‐western and north‐western parts of China and even in Southeast Asia.

Green hybrid composites partially reinforced with flax woven fabric and coconut shell waste-based micro-fillers

This research is focused on hybrid green composites using flax woven fabric in which the matrix phase was further reinforced with coconut shell waste-based cellulosic microparticles as fillers. Mesoscale mechanical models were successfully developed to simulate the tensile properties of such hybrid composites based on hybridization of fibers and biobased materials using epoxy resin. S-glass fabrics with plain, twill and biaxial constructions, were used as the outer layers, while plain-woven flax fabric was used as the middle layer. A high level of agreement was observed between the experimental and predicted values. The static tensile tests were followed by cyclic tensile tests, microscopic analysis of fracture surfaces and dynamic mechanical analysis. The influence of the hybrid fabric geometry and combination with biowaste-based micro cellulosic material was observed to significantly influence the tensile properties determined by both experimental and numerical analysis. Dynamic mechanical analysis also validated the quasistatic measurements. A higher storage modulus and loss modulus were registered for the hybrid composites impregnated with a 1 % bio filler-based matrix. The damping factor (tan delta) was lower for the hybrid composites than for the nonhybrid samples and the control samples from the pure matrix. This difference is attributed to the stronger interface between the fibers and the particle-based matrix, which restricts the molecular mobility and increases the stiffness of the composites. Fractographic images were obtained by scanning electron microscopy (SEM) to study the failure modes and mechanisms of the composite samples. The microparticles were uniformly dispersed in the epoxy resin and thus enabled microcracking rather than macrocracks. The failure mainly occurred due to fiber failure, matrix cracking and delamination. Such hybrid composites are useful for exterior and interior components in automotive applications.

Evolution of pore structure and cement composition during weathering of conglomerate at Mogao Grottoes in alkaline and arid regions, NW China

Numerous conglomerate grottoes have been excavated and preserved in the arid and alkaline regions of NW China. After millennia of weathering, these conglomerate grottoes have suffered from various weathering issues (such as seepage and collapse) that are internally governed by the distribution of pore networks and the degree of cementation. However, studies on conglomerate weathering have mostly been reported in humid and tropical climates, where intensive chemical weathering occurs. Additionally, characterizations of pore evolution during conglomerate weathering have been restricted due to limitations in detecting pore size and pore type using a single pore characterization method. To fill this gap, this study jointly used mercury intrusion porosimetry (MIP) and computed tomography (CT) to characterize the pore evolution process during conglomerate weathering at Mogao Grottoes, a world heritage site in NW China. Mineralogical, hydrological, mechanical and microscopic characterization were also conducted to understand the changes in compositions of bulk samples and cements during weathering. Results revealed that the majority of pores in conglomerate are concentrated in macropores > 5 μm, followed by mesopores and micropores. During weathering, volume fraction of macropores significantly increases and that of micropores decreases, with median/average pore diameters experiencing an 8- to 10-fold increase. Permeability, porosity and fractal dimension exhibited strong positive linear correlations with median/average pore diameters. Throughout weathering, the abundances of calcite and clay minerals show notable decrease, particularly in cements, resulting in an enrichment of feldspars. Frequently occurring sand-carrying wind activities and salt weathering in arid regions are inferred to be responsible for the major cement loss and porosity generation through physical processes. Our combined MIP-CT method for pore network characterization is also applicable to other lithologies with a wide range of pore sizes. The proposed mechanism of pore evolution and cementation failure provides a scientific base for protecting stone heritages in arid zones.

Environmental behavior and risk of the emerging organic contaminants halogenated carbazoles in chemical industrial park clusters

Polyhalogenated carbazoles (PHCZs) are emerging organic contaminants and have attracted extensive concern because of their widespread occurrence and dioxin-like toxicity. However, the distribution characteristics, environmental behavior, and fate of PHCZs are still poorly understood. In this study, 74 composite environmental samples from 21 Chinese cities were collected around industrial parks in the Yangtze River Delta. The PHCZ concentration ranges in sediment and soil samples were 12.7–5.21 × 103 and 34.6–1.81 × 103 ng/g, respectively, which is equivalent to or higher than those of well-known persistent organic pollutants in the similar areas. The dominant congeners of PHCZs in sediment and soil were 3-chlorocarbazole and 3,6-dichlorocarbazole. Industrial emissions, especially from printing and dyeing textiles, were the main contributors to the high PHCZ environmental concentrations. Potential toxic effects of the PHCZs were evaluated using the toxic equivalent (TEQ) method. The TEQs of PHCZs in sediment and soil were up to 550 and 554 pg TEQ/g dry weight, respectively. The estimated TEQ value of sediment and soil exceeded the corresponding safety guideline, which indicated that PHCZs in the Yangtze River Delta posed high health risks. This study provides an important theoretical basis for controlling and reducing the ecological risks of PHCZs in the chemical industry. At the same time, it also provides reference for the priority control and revision of discharge standards for PHCZs in sewage treatment plants in future.

Dual photosensitizers material for photodynamic theraphy

Abstract Fluoride-based upconversion luminescent materials have the advantage of low phonon energy, which can effectively reduce the non-radiative transition process, so that materials have higher luminous efficiency than other matrix materials. The core–shell NaGdF4:Er3+, Yb3+ @NaGdF4:Tm3+, Yb3+ nanoparticals were synthesized by thermal decomposition method. The core–shell structure can effectively avoid the surface quenching effect, meanwhile, Tm3+ in the shell transmits part of the photons in its excited state to Er3+, effectively enhancing the red emission of Er3+ and improving the luminous efficiency of the samples as a whole. The samples were further coated with a layer of mesoporous silica(mSiO2), where the photosensitizer(PS) Ce6 (red light activated) and MC540 (blue-green light activated) were compounded on through covalent bonds and electrostatic forces, respectively. So that three visable lights include red, green, and blue are all emitted from the sample to activate the PSs to produce reactive oxygen species (ROS) under 980 nm laser irradiation. In cells experiments, the samples were modified with folic acid (FA), which can mediated the cancer cells to target endocytosis. Notable photodynamic therapy (PDT) efficiency was observed under this dual-photosensitizers composite samples for its ROS generation.