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As the core component of lightning arrester, the performance of ZnO varistor directly affects the protection level of lightning arrester. Under the action of long‐term AC voltage, the varistors are prone to AC aging, which leads to the deterioration of its performance parameters and microstructure, resulting in the failure of the varistors. In this paper, the effects of MnO2${\text{MnO}}_{2}$ doping on the voltammetry and double Schottky barrier characteristics of ZnO varistors under AC were studied by means of C--V$C\hbox{--}V$, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy characteristic testing. The AC accelerated aging test was carried out for 168 h under 135∘C$^\circ\text{C}$ and 0.85 ratio of peak voltage. The results showed that the introduction of Mn4+${\text{Mn}^{4+}}$ inhibited the migration of interstitial zinc ions to grain boundaries and decreased the AC aging rate. The aging rate was lowest when 1.5 mol% MnO2${\text{MnO}}_{2}$ was doped. [ABSTRACT FROM AUTHOR]

The strategies for optimizing the morphology/structure and regulating the active sites of materials are effective ways to improve their electrocatalytic performance in the hydrogen evolution reaction (HER) and electrooxidation reaction. Herein, we demonstrate a facile strategy for constructing a NiO/NiCo2O4 porous nanowire catalyst on nickel foam (NiO/NiCo2O4/NF) as a bifunctional electrocatalyst to enhance the electrocatalytic performance for coupling the HER with the glucose oxidation reaction (GOR). Benefiting from the unique 1D porous nanowire structure and enhanced interfacial synergistic effect of the bicomponent catalyst, optimized NiO/NiCo2O4/NF-300 exhibited remarkable electrocatalytic activities for the GOR and HER with low potentials of 1.128 V and 0.212 V, respectively, at 100 mA cm−2. Moreover, the GOR exhibited a high yield of 72% for formic acid. This study provides a promising and simple strategy for the construction of 1D NiO/NiCo2O4 porous nanowire electrocatalysts with rich heterogeneous interfaces and paves a facile pathway for accelerating biomass electrochemical reaction-assisted hydrogen production. [ABSTRACT FROM AUTHOR]

The development of cost-effective oxygen reduction reaction (ORR) catalysts is of great importance and urgency for green energy technologies. Herein, the uniform Co nanoparticles encapsulated in two-dimensional (2D) nitrogen-doped graphitic-carbon nanosheets (Co@N–C) were synthesized by a one-step solvent-free, template-free, and scalable green pyrolysis strategy. Originating from the mutually reinforcing effect between Co nanoparticles and N–C active sites in the stable 2D porous conductive nanosheet structure, the optimized Co@N–C-700 obviously accelerates the catalytic performance for the ORR under both alkaline and acidic conditions. Especially, it showed good performance compared to 20wt% Pt/C-JM in terms of higher half-wave potential (E1/2 = 0.86 V), larger current density (JL = 6.1 mA·cm–2), and better stability, as well as stronger resistance to methanol crossover. In addition, the 2D Co@N–C-700 still exhibits superior operation performance to commercial Pt/C in a hybrid Zn–air battery test. [ABSTRACT FROM AUTHOR]

Dielectric materials with excellent thermal stability, mechanical properties, and thermal conductivity are highly desirable for advanced electronics and electrical equipment. However, it remains a significant challenge to develop a single material with these properties. Here we describe a new strategy to prepare dielectric paper by combining one-dimensional aramid nanofiber (ANF) with two-dimensional fluorinated graphene (F-graphene) through a vacuum-assisted filtration method. The obtained ANF/F-graphene paper exhibits a low dielectric constant of 1.92 at 103 Hz and its electrical breakdown strength is 17.6% higher than that of the neat ANF paper, owing to the presence of F-graphene, which significantly suppresses the accumulation of space charge in the prepared paper. Moreover, high mechanical strength (>200 MPa), thermal conductivity (6.29 Wm−1K−1), and thermal decomposition temperature (>500°C) are simultaneously achieved for the ANF/F-graphene paper. These findings highlight the fabrication of multifunctional dielectric materials and broaden their practical applications in the field of high-temperature electronics and devices. [ABSTRACT FROM AUTHOR]

Indoor air pollution is ranked the 5th in the Global Burden of Disease index of the World Health Organization (WHO). Almost half of the world's population depends on biomass fuels to meet their basic energy requirements for cooking, lighting and space heating. When fuel is badly combusted in poorly designed stoves, the fuel-stove combination results in high level of noxious emissions entering the home, accumulating to dangerous levels. In this study, a Chinese unvented top lit updraft (TLUD) biomass stove was operated with three different biomass pellets formed from corn stover, cotton stalk and peanut shells. The performance tests were conducted according to the latest standard from the Chinese Ministry of Agriculture. The calorific value, moisture level, volatile matter and elemental composition are reported for each. The thermal efficiencies of the stove were 15.3%, 10.1% and 14.4%, respectively. The cooking powers were 2.68 kW, 1.61 kW and 1.57 kW. The exhaust was collected using a hood and tunnel. The CO, NO and NOX were drawn after passing 1.5 m along the tunnel and the Particulate Matter (PM) was sampled after 1.6 m. The Emission Factors (EF) for CO, NO, NOX and PM10 are reported on both a mass per unit energy delivered to the pot (g/MJNET) and a mass per mass of fuel basis (g/kg). The range for CO was 4.56-7.61 g/MJNET (11.25-21.25 g/kg); NO was 0.75-1.23 g/MJNET (2.09-3.04 g/kg); NOx was 1.13-1.90 g/MJNET (3.14-4.86 g/kg); PM10 was 0.59-0.85 g/MJNET (1.67-2.09 g/kg). The range in these values was more significantly influenced by the fuel moisture content and the percentage of volatile matter than by variations in the elemental composition. [ABSTRACT FROM AUTHOR]

Testing of biomass stove performance is mainly based on the use of water boiling or heating as a surrogate for cooking tasks. Boiling of water is prescribed as a simulation of common cooking tasks and is used for comparison of the performance of stoves under different operating conditions. Tests are designed to evaluate biomass stoves by providing quantitative and qualitative information about their thermal and emission performance. In some developing countries, notably China, India, Mongolia, and South Africa, water boiling or heating tests focus on the overall thermal performance as a fuel consumption proxy, again with narrowly defined operating conditions. During the past few years, several newly developed performance evaluation standards and protocols for cooking and space heating stoves based on solid biofuels have been developed. National standards differ significantly from one country to the other because of inhomogeneous local conditions, widely varying cooking habits, the level of industrialisation and cultural preferences. All those stove testing standards and protocols have been tried and found to be prone to systematic and conceptual errors, virtually none of them having been professionally and scientifically reviewed. The current paper reviews several different approaches to a widespread need for results of stove performance tests to be comparable and identifies a number of calculations and conceptual errors that materially affect the outcome of stove tests. Recently, research and development work promoting the dissemination of improved biomass stoves has attracted global participation. It is essenial that, as far as possible, all conceptual and systematic errors should be identified, corrected and avoided during the process of the development of acceptable international standards and protocols. [ABSTRACT FROM AUTHOR]

Periodontal disease (PD) is viewed today as multifactorial problems initiated and sustained by bacteria but significantly modified by the body’s response to bacterial plaque. Recent studies have suggested that gene polymorphisms could be involved in the pathophysiology of periodontitis. This study aimed to investigate a possible correlation of the polymorphisms of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) with PD.

Inventory analysis of greenhouse gas emission for large-scale biogas plants using carbon footprint method still needs to be improved. Based on the life cycle theory, the application of carbon footprint on four large-scale biogas plants was analyzed in this paper, which comprehensively considered project progresses of civil engineering construction, operation and comprehensive utilization of residues and slurry. Also the greenhouse gas emissions during the construction and waste removal stages were analyzed and estimated. The carbon footprint of those plants was analyzed in different types and scales. The results showed that the larger scale plant will produce relatively lower carbon footprint. The greenhouse gas emission of energy production, utilization during the period of anaerobic digestion accounted for more than 96% of the entire life cycle emission. The proportion of greenhouse gas emissions on equipment, demolition recycling and transportation phases was smaller, which was less than 1.5% and should be simplified in calculation. The greenhouse gas emission of building materials production can be ignored. [ABSTRACT FROM AUTHOR]

The load-bearing performance of a RC simply supported beam bridge was comprehensively detected and evaluated. The appearance detection results show that there is a large area of damaged and exposed reinforcement in the main girder and diaphragm plate of the bridge. The detecting results of material condition and state parameters show that the durability of the bridge is insufficient, the risk of steel corrosion is large, and the strength condition of concrete material is poor. The load test results show that the bearing capacity of the bridge does not meet the requirements. In view of the current situation of the bridge, a comprehensive reinforcement treatment scheme was proposed, in which modified epoxy mortar is used to repair the main beam and diaphragm of the whole bridge, steel plate is pasted to reinforce the main beam of the whole bridge, and anticorrosive coating is applied on the main beam and diaphragm.

Abstract Background Cardiovascular disease (CVD) is the leading cause of global disease burden. Although stroke was thought to be more prevalent than coronary heart disease (CHD) in Chinese, the epidemic pattern might have been changed in some rural areas nowadays. This study was to estimate up-to-date prevalence of CVD and its risk factors in rural communities of Fangshan District, Beijing, China. Methods A cross-sectional population survey was carried out by stratified cluster sampling. A total of 58,308 rural residents aged over 40 years were surveyed by face-to-face interview and physical examination during 2008 and 2010. The standardized prevalence was calculated according to adult sample data of China's 5th Population Census in 2000, and the adjusted prevalence odds ratio (POR) was calculated for the association of CHD/stroke with its cardiovascular risk factors in multivariate logistic regression models. Results Age- and sex-standardized prevalence was 5.6% for CHD (5.2% in males and 5.9% in females), higher than the counterpart of 3.7% (4.7% in males and 2.6% in females) for stroke. Compared with previous studies, higher prevalence of 7.7%, 47.2%, 53.3% in males and 8.2%, 44.8%, 60.7% in females for diabetes, hypertension and overweight/obesity were presented accordingly. Moreover, adjusted POR (95% confidence interval) of diabetes, obesity, stage 1 and stage 2 hypertension for CHD as 2.51 (2.29 to 2.75), 1.53 (1.38 to 1.70), 1.13 (1.02 to 1.26) and 1.35 (1.20 to 1.52), and for stroke as 2.24 (1.98 to 2.52), 1.25 (1.09 to 1.44), 1.44 (1.25 to 1.66) and 1.70 (1.46 to 1.98) were shown respectively in the multivariate logistic regression models. Conclusions High prevalence of CVD and probably changed epidemic pattern in rural communities of Beijing, together with the prevalent cardiovascular risk factors and population aging, might cause public health challenges in rural Chinese population.

Abstract Background The exact etiology of ischemic stroke remains unclear, because multiple genetic predispositions and environmental risk factors may be involved, and their interactions dictate the complexity. Family-based studies provide unique features in design, while they are currently underrepresented for studies of ischemic stroke in developing countries. The Fangshan/Family-based Ischemic Stroke Study In China (FISSIC) program aims to conduct a genetic pedigree study of ischemic stroke in rural communities of China. Methods/Design The pedigrees of ischemic stroke with clear documentation are recruited by using the proband-initiated contact method, based on the stroke registry in hospital and communities. Blood samples and detailed information of pedigrees are collected through the health care network in the rural area, and prospective follow-up of the pedigrees cohort is scheduled. Complementary strategies of both family-based design and matched case-spousal control design are used, and comprehensive statistical methods will be implemented to ascertain potential complex genetic and environmental factors and their interactions as well. Discussion This study is complementary to other genetic pedigree studies of ischemic stroke, such as the Siblings With Ischemic Stroke Study (SWISS), which are established in developed countries. We describe the protocol of this family-based genetic epidemiological study that may be used as a new practical guideline and research paradigm in developing countries and facilitate initiatives of stroke study for international collaborations.