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With the continuous reduction in transistor size, the power consumption issue associated with the adoption of Network-on-Chips (NoCs) in multicore systems has become increasingly prominent and severe, particularly in terms of static power consumption. Currently, the techniques employed to address the issue of static power consumption in NoCs can be broadly categorized into two forms: power gating and simplified router architecture. However, these designs face critical bottlenecks in maintaining network performance stability and flexibility. In this paper, we propose a power gating approach utilizing double buffering to conserve power. Firstly, we introduce the DBU-PG router architecture, which effectively reduces network power consumption by sharing an input buffer between every two input ports when the network load is low. Secondly, through improved arbitration and flow control mechanisms, packets can be efficiently transmitted between shared buffers. Finally, we propose an improved router architecture, DBU-PG2, which enables packets in different virtual channels of the same buffer to be executed concurrently. Based on evaluation in real application, our DBU-PG and DBU-PG2 routers achieved reductions of 69% and 66%, respectively, in static power consumption compared to the baseline. Additionally, DBU-PG2 reduced packet latency by 7.5% while incurring only a 2.3% increase in area overhead. [ABSTRACT FROM AUTHOR]

Tracing the sources of microplastics (MPs) across various environmental media is currently facing significant challenges due to their complex transportable features. In this study, we conducted a comprehensive identification of MP sources in Beijing water bodies by combining MP diversity and the conditional fragmentation model, thoroughly considering local multiple sources. The resemblance in MP community compositions implied shared or similar sources in rivers and lakes, and the sources were assorted and equivalent based on the high diversity of MPs. The conditional fragmentation model can act as a proxy of fragmentation characteristics of MPs. According to the model, suburban sewage, soils, and dry and wet deposition constituted significant sources of MPs in the rivers and lakes of Beijing. The extremely high abundance of MPs (520,000 items·m−3) in suburban sewage also confirmed it as a potential source. For MPs with different polymer types and morphologies, non-fibrous polypropylene (PP) was primarily controlled by soils, whereas the contribution of sewage sludge to fibrous polyethylene terephthalate (PET) was notable. Our study provides insights for more accurate source apportionment and contributes to a better understanding of MP fate in urban environment. [ABSTRACT FROM AUTHOR]

As a possible alternative to provide a continuous power supply for small and low-power devices, piezoelectric energy harvesting technology has attracted wide attention in the last decade. This paper developed a kind of flexible d31 type piezoelectric macro fiber composite (MFC) and the MFC cantilever harvester. The vibration energy harvesting properties of the harvester were discussed. The research results show that the MFC cantilever harvester has a good voltage response to the excitation signal, and the largest open circuit voltage amplitude appears at the resonance frequency. The open circuit voltage amplitude of the harvester is sensitive to the vibration acceleration, which increases nearly linearly with increasing the vibration acceleration when the vibration acceleration is less than 2.0 g. The increase of the piezoelectric ceramic fiber volume fraction in the MFC can improve the open circuit voltage of the harvester, but increases the stiffness of the harvester, which is disadvantageous to the long-term operational reliability of the harvester. The desired open circuit voltage or short circuit current can be achieved in practical application by connecting multiple MFCs in series or parallel. [ABSTRACT FROM AUTHOR]

The 1–3 connectivity epoxy resin modified cement based piezoelectric composites were developed to meet the requirement of concrete structural heath monitoring. The piezoelectric ceramic volume fraction on piezoelectric, dielectric and electromechanical coupling properties of the composites were discussed. The results showed that the relative permittivity of the piezoelectric composites increases linearly with increasing the PZT piezoelectric ceramic volume fraction, but the dielectric loss of the piezoelectric composites is a little bit larger than that of the PZT ceramic. The piezoelectric strain constant d33 of the piezoelectric composites is mainly contributed by PZT ceramic and is in proportion to PZT volume fraction, however, the piezoelectric voltage constant g 33 show the opposite variation. When PZT volume fraction decreases to 27.7%, g 33 value of the piezoelectric composites reaches to 75.0 (mV)·m·N−1. When PZT ceramic volume fraction is 62.33%, the thickness electromechanical coupling coefficient kt of the piezoelectric composites is the largest of 66.73%. The acoustic impedance Z of the piezoelectric composite is close to that of the concrete when PZT ceramic volume fraction is less than 44.44%. [ABSTRACT FROM AUTHOR]

Vanadium (V) is a potential toxic pollutant, and thus, V pollution in reservoir sediment should be scientifically evaluated because reservoirs are the main source of drinking water in China. However, the pollution assessment of V in reservoir sediment is often overestimated or underestimated due to the limitation for selecting local background values. In this study, the selection of the V background value in sediments was based on regional geochemical baseline (RGB) model. Multiple methods including geo-accumulation index (Igeo), potential ecological risk index (EI), and health risk assessment were applied to evaluate V pollution in sediment cores collected from the Panjiakou–Daheiting Reservoirs (PDR). The results show that the mean value of V concentrations in the PDR sediment cores was 92.86 mg/kg (57.69–141.19 mg/kg), which is higher than the soil background in Hebei Province and stream sediment values in China. V concentrations in the Panjiakou Reservoir were higher than those in the Daheiting Reservoir. The RGB value of V was 96.33 mg/kg in the PDR sediments. A comparison of the V concentrations and RGB values in the sampling sites indicated that half of these sites are impacted by anthropogenic inputs. Among the sites influenced by human activity, the average anthropogenic contribution was 9.9%, suggesting that majority of V in the PDR sediments originated from natural source. The pollution assessments of V were evaluated using Igeo and EI with RGB as the background value, and results indicated that the sediments in the PDR were not polluted with V. The environmental impact assessment model was also established for calculating V accumulation in fish due to sediment resuspension. Then, health risk assessment model was applied to further calculate the health risk to residents due to fish consumption. The evaluated target hazard quotient demonstrated that local fish consumption produced no adverse effect on human health during sediment disruption. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous TiO2-xNx nanoparticles were synthesized by selective dissolving of Si in N-doped Ti-Si binary oxides, which were nitridized at 900 °C in a flow of ammonia gas, and the mesoporous TiO2-xNx photocatalysts were then modified by depositing Pt through a microwave polyol method. The samples were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), N2 adsorption-desorption, UV-vis spectroscopy and X-ray photoemission spectroscopy (XPS). The results indicated that the addition of SiO2 remarkably changed the phase composition, BET-specific surface area and the photocatalytic H2 production activity of TiO2-xNx nanoparticles. The incorporation of Si in Ti-Si binary oxides can suppress phase transformation of TiO2 from anatase to rutile and inhibit the TiO2 crystallite growth up to 900 °C. The BET surface area of the mesoporous TiO2-xNx nanoparticle was >138 m2 g−1 while with a crystallite size <10 nm, and the sample had a good visible light response. Photocatalytic hydrogen production results showed the N-doped Pt/TiO2 derived from Si: Ti = 1:1 of Ti-Si binary oxides exhibited the highest H2 evolution rate as high as 15.2 μmol g−1 h−1 under visible light irradiation, which is almost 10 times larger than commercial TiO2 nanoparticles P25. In addition, the co-catalyst optimized amount of Pt required for optimal photocatalytic H2 production activity was 2.0 wt%.Mesoporous TiO2-xNx nanoparticles with high BET surface area and less than 10 nm grain size were synthesized by selective dissolving of Si in N-doped Ti-Si binary oxides after calcined at 900 °C. The mesoporous Pt/TiO2-xNx exhibited H2 evolution rate as high as 15.2 μmol g−1 h−1, which is almost 10 times larger than P25. What’s more, the co-catalyst optimized amount of Pt required for optimal photocatalytic H2 production activity was 2.0 wt%. Mesoporous TiO2-xNx nanoparticles were synthesized by selective dissolving of Si in N-doped Ti-Si binary oxides.The grain size of the mesoporous TiO2-xNx with high BET surface area is <10 nm after calcined at 900 °C.Mesoporous Pt/TiO2-xNx exhibited H2 evolution rate as high as 15.2 μmol g−1 h−1, which is almost 10 times larger than P25.The co-catalyst optimized amount of Pt required for optimal photocatalytic H2 production activity was 2.0 wt%. [ABSTRACT FROM AUTHOR]

The Three Gorges Dam in China is the world's largest dam. Upon its completion in 2003, the Three Gorges Reservoir (TGR) became the largest reservoir in China and plays an important role in economic development and national drinking water safety. However, as a sink and source of heavy metals, there is a lack of continuous and comparative data on heavy metal pollution in sediments. This study reviewed all available literatures published on heavy metals in TGR sediments and further provided a comprehensive assessment of the pollution tendency of these heavy metals. The results showed that heavy metal concentrations in TGR sediments varied spatially and temporally. Temporal variations indicated that Hg in tributaries, as well as As, Cd, Cr, Cu, Ni, Pb, and Zn in the mainstream, exhibited a higher probability to exceed background values after the impoundment of TGR. Pollution assessments by contamination factor, geoaccumulation index, and potential ecological risk were similar. High Cd and Hg concentrations in both the mainstream and tributaries are a cause for much concern. However, sediment quality guidelines produced different results, as most previous studies adopted different sampling and measurement strategies. The data inconsistencies and lack of continuity regarding the reservoir confirm the need for a continuous monitoring network and the development of quality criteria relevant to the sediments of the TGR in the future. [ABSTRACT FROM AUTHOR]

The South-to-North Water Diversion Project has aroused widespread concerns about the potential ecological risks posed by the project, especially for the Miyun Reservoir (MYR). The potential release risk of metals from the flooded riparian soils into MYR after water impoundment is one of key scientific problems. In this study, riparian soil samples were collected considering three vertical heights (130, 140, and 145 m) and four types of land uses in the MYR areas, namely, forestland, grassland, wasteland, and recreational land. We analyzed soils texture, the content and chemical fractionations of seldom monitored trace elements (SMTEs): Li, Be, B, V, Co, Ni, Ga, Sn, Sb, Tl, and Bi). Results showed that the four types of soils in MYR had the similar textures, while recreational land showed significantly higher contents of Ni and V. Additionally, there were no significant differences found for most SMTEs (except for V) at different vertical heights in each soil type, while the concentrations of V at 140 and 145 m in forestland and recreational land were significantly higher than those at 130 m. However, a comprehensive evaluation of potential ecological risk (contamination factor (CF), modified degree of contamination (mCd), and geoaccumulation factor ( I )) consistently indicated the insignificant contaminations of all SMTEs in MYR soils before water impoundment. The Community Bureau of Reference (BCR) sequential extraction results showed that the chemical fractionations of SMTEs were independent of land use patterns and vertical heights. Co in reducible fractions and Ni were identified as the candidates which had potential to release into MYR when the lands were submerged. Principal component analysis (PCA) and cluster analysis (CA) results suggested that a portion of V, Co, and Ni may originate from anthropogenic activities, and the coal combustion was possibly the main anthropogenic source. The findings of this work would provide valuable information on the environment management of MYR and offer a reference for the investigation on the effect of water impoundment on potential release risk of SMTEs in MYR. [ABSTRACT FROM AUTHOR]

Biochar is widely used in agricultural soils or heavy metal-polluted soils to improve the quality of the soils, which would affect the growth of the plant. However, the information of biochars' effect on the plant growth was still lacking, especially for the physiological response of the plant. Pot experiments were used to examine the effect of willow-derived biochars at two temperatures (450 and 600 °C) on cadmium (Cd) accumulation in pepper and to reveal the response of physiological parameters to exogenous Cd stress (1 and 5 mg/kg). The results showed that the accumulation of Cd in pepper roots was higher than that in pepper shoots. For low level of Cd treatments, high additional rates of the biochars could obviously reduce the accumulation of Cd in the pepper roots. Moreover, there was a negative correlation between the C content of the biochar-amended soils and the Cd content of the pepper root, suggesting that the application of biochar to the soil decreased the Cd accumulation in the root. A positive relationship between the H/C ratios of biochar-amended soils and their corresponding Cd concentrations in pepper root indicated that low thermal temperature-derived biochar could play an important role in immobilizing Cd in the soil. Furthermore, on the condition of low Cd level of treatments, the malondialdehyde content decreased in biochar-amended soils, especially at high biochar application rate. The chlorophyll content increased with increasing the rates of the biochar application. The physiological parameters indirectly proved that the application of biochar did not always alleviate the toxic effects of Cd on pepper leaves at high Cd concentration. [ABSTRACT FROM AUTHOR]

Street dusts from heavy density traffic area (HDTA), tourism area (TA), residential area (RA), and educational area (EA) in Beijing were collected to explore the distribution, health risk assessment, and source of lead (Pb). The average concentration of Pb in TA was the highest among the four areas. Compared with other cities, Pb concentrations in Beijing were generally at moderate or low levels. The average value (14.05) of ecological risk index (RI) indicated that Pb was at 'low pollution risk' status. According to the calculation on hazard index (HI), the ingestion of dust particles of children and adults was the major route of exposure to street dusts in four studied areas, followed by dermal contact. The lower values of HI than 1 further suggested that non-carcinogenic risks of Pb in the street dusts were in the low range. Comparing Pb/Pb and Pb/Pb ratios of street dusts with other environmental samples, it was found that atmospheric deposition of coal combustion dust might be the main pathway for anthropogenic Pb input to the street dusts in four functional areas. [ABSTRACT FROM AUTHOR]

The impoundment of the Three Gorges Reservoir (TGR) in China influences the quality of the water supply. Surface sediment samples from the TGR mainstream and three tributaries were collected. Acid volatile sulfide (AVS), simultaneously extractable metals (SEMs), and the fraction of organic carbon (f) were used to assess the toxicity of heavy metals. Sediment quality guidelines (SQGs) were established using the equilibrium partitioning approach. The results showed that the surface sediments were found to be oxic or suboxic. AVS concentrations in sediments were relatively low, below SEM concentrations. The [SEM] − [AVS] model indicated that all sediments possibly have adverse effects on aquatic life. However, ([SEM] − [AVS])/f predicted no adverse biological effects in some areas of the Meixi and Caotang Rivers, while adverse effects to aquatic life were uncertain for the other sediments. The partitioning coefficients, water quality criteria, and residual metals in the sediments were the main factors influencing the SQGs for the TGR, while the metals bound to AVS had a negligible effect. The normalized TGR SQGs were all much higher than the existing standards except for cadmium and copper. The differences might be attributed to the approaches used for derivation of SQGs and the physical and chemical characteristics of the sediments. [ABSTRACT FROM AUTHOR]

The piezoelectric ceramic PbSr(ZrTi)O + 0.1 wt% (NiO + CrO) + x wt%CeO (PCrNi-4) was prepared using a traditional solid state sintered method. The effects of CeO doping on phase structure, microstructure, piezoelectric, and dielectric properties were analyzed by means of XRD, SEM, and electrical property measurements. The results indicate that when CeO doping content is 0.3 wt% and sintering temperature is 1,280 °C, the dielectric loss value of the ceramic is the least with a value of 0.00238, and the dielectric factor $$ \varepsilon_{33}^{\text{T}} $$, piezoelectric strain factor d, planar electromechanical coupling coefficient K and mechanical quality factor Q of the ceramic is 1400, 375 pCN, 0.68, and 460, respectively. [ABSTRACT FROM AUTHOR]

The influences of water/cement ratio and admixtures on carbonation resistance of sulphoaluminate cement-based high performance concrete (HPC) were investigated. The experimental results show that with the decreasing water/cement ratio, the carbonation depth of sulphoaluminate cement-based HPC is decreased remarkably, and the carbonation resistance capability is also improved with the adding admixtures. The morphologies and structure characteristics of sulphoaluminate cement hydration products before and after carbonation were analyzed using SEM and XRD. The analysis results reveal that the main hydration product of sulphoaluminate cement, that is ettringite (AFt), decomposes after carbonation. [ABSTRACT FROM AUTHOR]

The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR. [ABSTRACT FROM AUTHOR]