53 research outputs found
Energy input and output of a rural village in China - the cas of the "Beijing Man village" /District of Beijing
The rapid development of the economy has created an increasing demand for energy in China. The limited resources of fossil energy are a risk for the development of China. Sustainable agriculture like organic farming (Green AAA in China) with biomass energy - as done in developed countries like Germany - is an option to reduce these risks. In China, agriculture is not energy efficient, and the intensive farming is not sustainable. The scientific challenge is to develop sustainable farming systems which can fulfill national food security, food safety and considerable renewable energy production without harming the environment, and are acceptable to the people and the economy. The protection and intelligent utilization of resources is the core of rural village development.
To explore the potential of recent Chinese agriculture for the development towards a multi-functional farm for food and energy production, a village in the adjacent area of Beijing has been selected: the “Beijing Man village”. About 1,900 people live in the village and 140 hectares of the 240 hectare total land are available for farming. The major agricultural activity is pork production (capacity of 10,000 pigs per year) and dairy farming (40 dairy cows).
In 2004, the energy input and output of this village was evaluated and taken as a basis for a model of sustainable farming for food and biogas production. The study explored that the gross energy production from crops in the “Beijing man village” was about 19,103 GJ/year. It was obvious that the crop production was not sufficient for the feed demand of the animal husbandry (pigs and cows). 60% of the corn used as feed stuff was purchased on the market. The reason was, that the purchasing of corn was cheaper than the own production. The low competitive crop production due to the low efficiency resulted in the decrease of cultivated crop land from 140 ha to 80 ha in the past four years (two harvests per year).
On the other hand, there was much more manure produced as suitable and applicable for crop production. Therefore manure was exposed in open air in a pond like waste. This is risky for public hazards like ground water contamination and zoonosis diseases. Therefore the farming system is not sustainable, risky and not efficient. There is a potential of the optimization of the cropping and animal husbandry interaction as well as the development of renewable energy production in the village. The main development chains are the improvement of the energy efficiency of crop production, the reduction of animal husbandry to a sustainable animal-land-ratio and the introduction of biogas production with manure and cropping by-products
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Synthesis of Silver Nanowires with Reduced Diameters Using Benzoin-Derived Radicals to Make Transparent Conductors with High Transparency and Low Haze.
Reducing the diameter of silver nanowires has been proven to be an effective way to improve their optoelectronic performance by lessening light attenuation. The state-of-the-art silver nanowires are typically around 20 nm in diameter. Herein we report a modified polyol synthesis of silver nanowires with average diameters as thin as 13 nm and aspect ratios up to 3000. The success of this synthesis is based on the employment of benzoin-derived radicals in the polyol approach and does not require high-pressure conditions. The strong reducing power of radicals allows the reduction of silver precursors to occur at relatively low temperatures, wherein the lateral growth of silver nanowires is restrained because of efficient surface passivation. The optoelectronic performance of as-prepared 13 nm silver nanowires presents a sheet resistance of 28 Ω sq-1 at a transmittance of 95% with a haze factor of ∼1.2%, comparable to that of commercial indium tin oxide (ITO)
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Text mining MEDLINE to support public health
Today’s society is data rich and information driven, with access to numerous data sources available that have the potential to provide new insights into areas such as disease prevention, personalised medicine and data driven policy decisions. This paper describes and demonstrates the use of text mining tools developed to support public health institutions to complement their data with other accessible open data sources, optimize analysis and gain insight when examining policy. In particular we focus on the exploration of MEDLINE, the biggest structured open dataset of biomedical knowledge. In MEDLINE we utilize its terminology for indexing and cataloguing biomedical information – MeSH – to maximize the efficacy of the dataset
Investigation of Blade Tip Shape for Improving VAWT Performance
Vertical axis wind turbine (VAWT) is a competitive power generation device due to structural simplicity, wind direction independence, no yaw mechanism required, easier maintenance, and lower noise emission. However, blade tip vortex will be generated at both ends of the blade during the rotation, resulting in torque loss and efficiency reduction. In this paper, computational fluid dynamics is used to study blade tip vortex and its reduction technique of a single-blade VAWT rotor in real scale. By monitoring the force and flow field at different heights of the blade, the influence ranges of tip vortex are obtained. The reduction effect of the bulkhead obtained from the blade profile curve is studied, and the size of the bulkhead is optimized. On the basis of adding the optimal bulkhead, the influence of the supporting strut is also explored. The joint action is obtained by changing the location of the supporting strut. The results show that the top supporting strut-bulkhead structure is the optimal position. The power-extraction efficiency of the rotor with this integrated structure is significantly improved at optimal tip speed ratios (TSRs) and higher TSRs
Vorticity Budget and Formation Mechanisms of a Mesoscale Convective Vortex in a Heavy-Rainstorm Episode
Mesoscale convective vortices (MCVs) often cause rainstorms. To deepen our understanding of MCV formation mechanisms, reanalysis data from the National Centers for Environmental Prediction and the Weather Research and Forecasting model were used to simulate MCV activity in East China in August 2009. The simulations could reproduce the MCV and associated convective activities well. The vorticity budget and MCV formation mechanisms were then analyzed. The results show that the planetary vorticity advection is much smaller than other terms of the vorticity equation. The MCV initiates in the convective precipitation region and below 800 hPa. When the MCV initiates, there are vorticity-variation couplets within the vortex, and the MCV moves towards the positive vorticity-variation direction. In positive vorticity-variation areas, the divergence term and the tilting term are the vorticity source. The equilibrium response to diabatic heating is one of the forming mechanisms of this MCV. The latent-heating level is relatively low in this MCV case, and the MCV-forming level is also relatively low. Another forming mechanism of this MCV is the tilting of the horizontal vortex tube caused by the upward motion. At the MCV initiation, the perturbation scale of the vortex is found to be larger than the Rossby deformation radius, and thus the MCV could have a long duration
Mining MEDLINE for the visualisation of a global perspective on biomedical knowledge
There is an ever increasing number of data sources that potentially could be used to gain new insights into areas such as disease prevention, policy formulation/evaluation and personalised medicine, but these are not optimised for use within an analytics type user interface. The MIDAS project was funded under a call for ‘Big Data supporting Public Health policies’ to develop a big data platform that facilitates the utilisation of healthcare data beyond existing isolated systems, making that data amenable to enrichment with open and social data. This aligns closely with a number of themes in Knowledge Discovery in Databases (KDD) in that the platform enables the integration of heterogeneous data sources, providing privacy-preserving analytics, forecasting tools and visualisation modules to deliver actionable information. Policy makers as a result will have the capability to perform data-driven evaluations of the efficiency and effectiveness of proposed policies in terms of expenditure, delivery, wellbeing, and health and socio-economic inequalities, thus improving current policy formulation, delivery risk stratification and evaluation. This H2020 project has a total of 15 partners from 5 EU countries as well as Arizona State University (ASU). The partners are Universities, SMEs and health departments in governmental institutions
Prognostic Value of ctDNA Mutation in Melanoma: A Meta-Analysis
Purpose. Melanoma is the most aggressive form of skin cancer. Circulating tumor DNA (ctDNA) is a diagnostic and prognostic marker of melanoma. However, whether ctDNA mutations can independently predict survival remains controversial. This meta-analysis assessed the prognostic value of the presence or change in ctDNA mutations in melanoma patients. Methods. We identified studies from the PubMed, EMBASE, Web of Science, and Cochrane databases. We estimated the combined hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) using either fixed-effect or random-effect models based on heterogeneity. Results. Sixteen studies including 1,781 patients were included. Both baseline and posttreatment detectable ctDNA were associated with poor OS (baseline detectable vs. undetectable, pooled HR = 1.97, 95% CI = 1.64–2.36, P<0.00001; baseline undetectable vs. detectable, pooled HR = 0.19, 95% CI = 0.11–0.36, P<0.00001; posttreatment detectable vs. undetectable, pooled HR = 2.36, 95% CI = 1.30–4.28, P=0.005). For PFS, baseline detectable ctDNA may be associated with adverse PFS (baseline detectable vs. undetectable, pooled HR = 1.41, 95% CI = 0.84–2.37, P=0.19; baseline undetectable vs. detectable, pooled HR = 0.43, 95% CI = 0.19–0.95, P=0.04) and baseline high ctDNA and increased ctDNA were significantly associated with adverse PFS (baseline high vs. low/undetectable, pooled HR = 3.29, 95% CI = 1.73–6.25, P=0.0003; increase vs. decrease, pooled HR = 4.48, 95% CI = 2.45–8.17, P<0.00001). The baseline BRAFV600 ctDNA mutation-positive group was significantly associated with adverse OS compared with the baseline ctDNA-negative group (pooled HR = 1.90, 95% CI = 1.58–2.29, P<0.00001). There were no significant differences in PFS between the baseline BRAFV600 ctDNA mutation-detectable group and the undetectable group (pooled HR = 1.02, 95% CI = 0.72–1.44, P=0.92). Conclusion. The presence or elevation of ctDNA mutation or BRAFV600 ctDNA mutation was significantly associated with worse prognosis in melanoma patients
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