34 research outputs found
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A hierarchical climatic zoning method for energy efficient building design applied in the region with diverse climate characteristics
The climate-responsive strategies for energy efficient building design and management require a detailed understanding of the local climatic conditions, while climate zones are fundamental to building regulations and the application of technologies. Smaller and more homogeneous climate zones could help policy-makers and building designers to improve building energy efficiency while improving the indoor thermal environment. A new climate zoning method, with two-tier classification designed for passive building design, is proposed, using climate data (degree-days, relative humidity, solar radiation and wind speed) with Hierarchical Agglomerative Clustering (HAC) following the Wardβs method. The method is applied to the Hot Summer and Cold Winter (HSCW) zone of China as a showcase, where there are no fine climate zones for energy efficient building design with diverse climate characteristics. Seven sub-zones that consider both cooling and heating demands are generated in Tier 1. In the second tier, the HSCW zone is further sub-divided into three humidity groups, three solar radiation clusters, and four wind speed clusters. To assess the impact of climate zoning on building heating and cooling, EnergyPlus simulations are conducted with the output of heating and cooling load. The cooling loads decrease from sub-zone A to B to C (mean = 82.8, 65.3, 43.8 kWh m-2, respectively) with sub-zone mean heating A1 larger than A2 and A3, B1 larger than B2, and C1 larger than C2, which is in accordance with the assumption made in the first-tier division. The higher wind speeds can raise the possibility of natural ventilation, and further increase the free-running period (FRP) when heating and cooling are not needed. The proposed zones are mapped and provide a useful reference for the policy/building code makers for heating and cooling strategies in this region. The method to create the climate zones could be applied in any region with local climate data
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Effectiveness of the thermal mass of external walls on residential buildings for part-time part-space heating and cooling using the state-space method
A high-resolution time interval numerical model is more accurate to analyze the building dynamic thermophysical processes in the intermittent occupancy, while relevant professional software, such as EnergyPlus, is not compatible with different time intervals. The present study aims to investigate the thermal mass effectiveness of external walls on the part-time part-space operation of heating and cooling of a typical residence. A high-resolution model of a typical 3-occupant residential apartment has been developed using the state-space method and validated by the simulation results from EnergyPlus. The model is then amended to calculate building energy demands with fixed heat and cold supply powers from the perspective of system control, in order to interpret the effectiveness of thermal mass with identical recommended U-value in the HSCW (Hot Summer and Cold Winter) zone in terms of room operative temperatures. It is found that high thermal mass does not help to reduce ideal building loads in the residential buildings in the HSCW zone, but it will improve indoor thermal comfort control in real engineering compared to low thermal mass. Regarding thermal insulation placements of heavy weight external walls under the same thermal mass, it is evidenced that the adoption of internal insulation weakens the thermal mass impact of the heavy weight wall composition compared to that of external insulation. It is inferred that the high thermal mass in the composition of external walls should be exposed to the indoor air to avoid overheating in the cooling conditions
An atlas of DNA methylomes in porcine adipose and muscle tissues
It is evident that epigenetic factors, especially DNA methylation, have essential roles in obesity development. Here, using pig as a model, we investigate the systematic association between DNA methylation and obesity. We sample eight variant adipose and two distinct skeletal muscle tissues from three pig breeds living within comparable environments but displaying distinct fat level. We generate 1,381 Gb of sequence data from 180 methylated DNA immunoprecipitation libraries, and provide a genome-wide DNA methylation map as well as a gene expression map for adipose and muscle studies. The analysis shows global similarity and difference among breeds, sexes and anatomic locations, and identifies the differentially methylated regions. The differentially methylated regions in promoters are highly associated with obesity development via expression repression of both known obesity-related genes and novel genes. This comprehensive map provides a solid basis for exploring epigenetic mechanisms of adipose deposition and muscle growth
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Natural ventilation potential for residential buildings in a densely built-up and highly polluted environment. A case study
The application of Natural Ventilation (NV) as a measure to improve comfort conditions in transition and summer periods has been a topic of research on the spotlight for years. However, there is a lack of knowledge about how the combined effect of a dense urban layout with high pollutant concentrations may affect its potential. This paper addresses this gap by running detailed thermal simulations for a typical apartment flat located in the Yuzhong district of Chongqing city (China) using a holistic approach that makes use of: i) wind pressure coefficients on building facades from urban-scale CFD simulations, ii) hourly measured values of PM2.5 concentrations and weather variables and iii) indoor environment measurements for validation purposes. Scenario analysis revealed the average amount of air change rates achievable in a year varies from 8 to 15 ACH according to the windows orientation. These figures drop down to around 2 ACH when taking into account reduced windows opening time when outdoor PM2.5 concentrations are too high. The resulting natural ventilation potential of the case study decreases from 4234β―h when outdoor pollution is neglected to 2707 and 529β―h when considering the exposure thresholds set by the Chinese government and the WHO respectively
MicroRNAome of Porcine Pre- and Postnatal Development
The domestic pig is of enormous agricultural significance and valuable models for many human diseases. Information concerning the pig microRNAome (miRNAome) has been long overdue and elucidation of this information will permit an atlas of microRNA (miRNA) regulation functions and networks to be constructed. Here we performed a comprehensive search for porcine miRNAs on ten small RNA sequencing libraries prepared from a mixture of tissues obtained during the entire pig lifetime, from the fetal period through adulthood. The sequencing results were analyzed using mammalian miRNAs, the precursor hairpins (pre-miRNAs) and the first release of the high-coverage porcine genome assembly (Sscrofa9, April 2009) and the available expressed sequence tag (EST) sequences. Our results extend the repertoire of pig miRNAome to 867 pre-miRNAs (623 with genomic coordinates) encoding for 1,004 miRNAs, of which 777 are unique. We preformed real-time quantitative PCR (q-PCR) experiments for selected 30 miRNAs in 47 tissue-specific samples and found agreement between the sequencing and q-PCR data. This broad survey provides detailed information about multiple variants of mature sequences, precursors, chromosomal organization, development-specific expression, and conservation patterns. Our data mining produced a broad view of the pig miRNAome, consisting of miRNAs and isomiRs and a wealth of information of pig miRNA characteristics. These results are prelude to the advancement in pig biology as well the use of pigs as model organism for human biological and biomedical studies
Pathogenic Factors and Mechanisms of the Alternaria Leaf Spot Pathogen in Apple
Alternaria leaf spot seriously threatens the sustainable development of the global apple industry, causing significant losses and reducing fruit quality and yield. The causal agent Alternaria alternata f. sp. mali (Alternaria mali, ALT) produces various molecules to modulate infection, such as cell wall-degrading enzymes, toxins, and elicitor-like molecules. ALT produces the host-specific AM-toxin, an important pathogenicity factor. ALT also releases effectors into apple cells that modify host defense, but these proteins have not yet been described. Here, we identified the pathogenic fungal types responsible for early defoliation from diseased leaves of Fuji (Malus domestica cv. βFujiβ) apple collected from five districts in Shandong Province, China. The ALT isolates ALT2 to ALT7 were pathogenic to four apple cultivars, with ALT7 being the most aggressive. We extracted mycotoxins (AM-toxin-2 to AM-toxin-7) from each isolate and used them to treat different apple varieties, which led to leaf-spot symptoms and damaged chloroplasts and nuclear membranes, followed by cell death. AM-toxin-7 produced the most severe symptoms, but chloroplasts remained intact when the mycotoxin was inactivated. Mass spectrometry identified 134 secretory proteins in ALT7 exosomes, and three secreted proteins (AltABC, AltAO, and AltPDE) were confirmed to be involved in apple pathogenesis. Therefore, ALT secretes AM-toxin and secretory proteins as an infection strategy to promote fungal invasion and overcome the host defense system
Quantification of Precipitation Using Polarimetric Radar Measurements during Several Typhoon Events in Southern China
Accurate quantitative precipitation estimation (QPE) during typhoon events is critical for flood warning and emergency management. Dual-polarization radar has proven to have better performance for QPE, compared to traditional single-polarization radar. However, polarimetric radar applications have not been extensively investigated in China, especially during extreme events such as typhoons, since the operational dual-polarization system upgrade only happened recently. This paper extends a polarimetric radar rainfall system for local applications during typhoons in southern China and conducts comprehensive studies about QPE and precipitation microphysics. Observations from S-band dual-polarization radar in Guangdong Province during three typhoon events in 2017 are examined to demonstrate the enhanced radar rainfall performance. The microphysical properties of hydrometeors during typhoon events are analyzed through raindrop size distribution (DSD) data and polarimetric radar measurements. The stratiform precipitation in typhoons presents lower mean raindrop diameter and lower raindrop concentration than that of the convection precipitation. The rainfall estimates from the adapted radar rainfall algorithm agree well with rainfall measurements from rain gauges. Using the rain gauge data as references, the maximum normalized mean bias ( N M B ) of the adapted radar rainfall algorithm is 20.27%; the normalized standard error ( N S E ) is less than 40%; and the Pearson’s correlation coefficient ( C C ) is higher than 0.92. For the three typhoon events combined, the N S E and N M B are 36.66% and -15.78%, respectively. Compared with several conventional radar rainfall algorithms, the adapted algorithm based on local rainfall microphysics has the best performance in southern China