Investigation of the sky optical conditions over selected stations in the major vegetation zones of Nigeria

Data-set of monthly global solar irradiance covering periods of at least 20 years over selected stations in Nigeria have been utilised to investigate the sky optical conditions over the five major vegetation zones of the country. The monthly variation of the clearness index for the selected stations has been investigated. Results show that the clearness index has its minimum in August which indicates reduced insolation during the monsoon month of August and maximum around November, December and February which shows high insolation. Statistical analysis of the monthly clearness index which gives the percentage depletion by the sky of the incoming insolation and the subsequent characterisation of the sky conditions based on this were also done. The results show that cloudy sky conditions prevail in the rainforest and mangrove swamp zones (e.g. Lagos, K_T=0.40) while clear sky conditions prevail in the Sudan and Sahel vegetation (e.g. Nguru K_T=0.66) and Kano (K_T=0.65).     

Evaluation of a cloud cover based model for estimation of hourly global solar radiation in Western Canada

Cloud cover based solar radiation models are relatively simple and convenient as the models require the input of cloud cover data which are mostly available from the meteorological stations. In this study, the performance of a cloud cover based solar radiation model (Kasten–Czeplak model) with original or locally fitted coefficients was evaluated for estimating the hourly global solar radiation for four different locations in Western Canada. The average value of R², mean bias error, and root mean square error are 0.69, ?61.6, and 157.9?W?m^?2, respectively, for the model with original coefficients, whereas 0.82, 4.4, 107.1?W?m^?2 with locally fitted coefficients. Results show that the Kasten–Czeplak model with locally fitted coefficients satisfactorily estimated the hourly solar radiation of four different locations in Western Canada. Also, the results indicate that the model with original coefficients has very limited accuracy under intermediate cloud cover conditions.     

既有居住建筑附属地下换热站降噪研究

为了降低既有建筑附属用房产生的噪声对居民生活的影响、改善居住建筑声环境,对既有居住建筑附属用房地下换热站的噪声源以及噪声传播途径进行了分析;以既有居住建筑地下换热站室内噪声实测数据为基础,对室内环境的声学特征进行分析。在综合考虑居民的健康和舒适的基础上,提出了针对该附属用房的降噪处理改造设计方案。经过改造后的空间噪声明显降低,空间声环境指标达到标准要求,有效地改善了居住建筑的声环境。文中提出的改造设计方案为制定民用建筑附属用房声学设计标准提供了技术支撑。     

The relative importance of moisture transfer,soil freezing and snow cover on ground temperature predictions

Predicting ground temperature is an important part of the analysis of geothermal resources assessment and use. Thus, we develop and validate one-dimensional numerical model for heat and mass transfer in partially frozen soils. The model is implemented in HVACSIM Plus and used to simulate the thermal regime of soil profile. In addition to modeling heat conduction, model variations also includes moisture transfer, snow accumulation and melting, and soil freezing and thawing. The results are compared against experimental measurements of ground temperature for three locations in Montana, USA. The differences between simulated depth temperature with and without snow cover and freezing and thawing of soil reveal that ground temperatures are predominantly influenced by these two factors. Considering moisture transfer slightly improves temperature predictions, although it increases computational time by one order of magnitude. To balance computational efficiency with prediction accuracy, we propose an equivalent moisture content of 40–60% saturation in predicting ground temperature.     

Effects of land use and changes in cover on the transformation and transportation of iron:A case study of the Sanjiang Plain,Northeast China

Wetland reclamation has been ongoing in the Sanjiang Plain since the mid-1950s,which has resulted in major changes in wetlands and the agriculture ecosystem in the region that have influenced the iron output to the Sea of Okhotsk and limited the primary productivity in the North Pacific Ocean.This study was conducted to investigate the chemical forms of iron in different aquatic environments(agricultural water including groundwater,paddy water,and canal water;wetland water including marsh water,marsh stream...     

地被植物的绿化工程应用

本文以温州市的相关绿化工程为例，对地被植物的应用方式进行了归纳和总结。并从地被植物的分类、生态习性、种植条件、品种特性、景观效果、种植密度以及后期养护效果等方面，对地被植物在绿化工程中的应用进行了详细的分析。     

Landscape as an Area Perceived through Activity: Implications for Diversity Management and Conservation

This article uses an activity-based understanding of landscape to explore values related to perceived land cover diversity. Perceptions within two user groups, members of landowner families and hiking tourists in a mountain area in western Norway, were related to a simultaneous land cover survey, and compared to experts' evaluations of land cover and to the aims of landscape protection in the area. Users perceived the area as being significantly more diverse and valuable than experts did, which stresses the importance of taking user perception into account in landscape protection and management. Some central landscape values were dependent upon land use outside the boundaries of the protected area. This illustrates that measures within structurally defined land units are not necessarily sufficient for maintenance of landscape values experienced by users. Land use in both respects, as an upholder of values and as a way of experiencing or perceiving them, should receive an increased role in the determination of management units.     

Trajectory Analysis of Forest Cover Change in the Tropical Dry Forest of Burkina Faso,West Africa

Forest cover decline is one of the most important environmental issues in the tropics. The present study was carried out in Burkina Faso, West Africa, and aimed at assessing the trajectories of forest cover change and measuring landscape metrics of the trajectory classes in order to better understand the processes of change. Landsat and ASTER images acquired over a period of 30 years were used for cover change detection and the Fragstats package was used to compute landscape metrics with five unifying change classes. Results showed a substantial increase in cropland with concurrent decline in forest cover. Deforestation represented 63% of the Percentage of Landscape (PLAND) in 2006, while reforestation accounted for only 28%. Both of these classes had high Normalized Landscape Shape Index (NLSI) values, indicating that they were present as scattered small patches. The old cultivation (30-year permanent cropland) was aggregated (IJI ≈ 0) while deforestation exhibited highly interspersed patches. The old forest and old cultivation presented lower Area Weighted Fractal Dimension Index (FRAC_AM), but deforestation and reforestation had the higher FRAC_AM. These results confirmed that there was a high level of deforestation and fragmentation in southern Burkina Faso and justify the need for a proper management plan to ensure the sustainable use of forest resources.     

Equality in death: Sigurd Lewerentz and the planning of Malmö Eastern Cemetery 1916–1973

The exponential growth of industrialized cities at the turn of the twentieth century led town planners and architects in Sweden to design new cemeteries and engage in the discussion with novel approaches to commemoration. Malmö Eastern Cemetery (1916–1973) was designed by Sigurd Lewerentz (1885–1975) and represented an ambitious experiment: a new scale of cemetery landscape, which involved planting vegetation anew and detracted from sweeping picturesque designs. This paper analyses how Lewerentz's approach to the equality of individual tombstones affected his design of Malmö Eastern Cemetery, both in terms of burial spaces for individuals and the commemorative public realm. Based on archival research and field work, this paper delves into the interplay between the cemetery designers and the different urban planners of Malmö over a period of dramatic transformation in the eastern districts of the increasingly industrialized city. Although Lewerentz initially differentiated between tombstones, after 1922 he reconsidered his cemetery plans, setting standards that made commemoration accessible to everyone while limiting individual choices. Lewerentz's homogenizing decisions in planning Malmö cemetery provide a lens through which to examine how equality has shaped discussions around commemoration, representing ideals of societies across history and the underlying tensions between individual freedom and society.     

基于CAE优化分析的汽车水箱盖中盖注塑模设计

针对汽车水箱盖中盖的结构特征,结合CAE技术对产品进行注塑成型过程模拟分析,确立了点浇口浇注系统并优化了冷却方案,在此基础上完成了注塑模设计。在模具结构设计中,提出用斜滑块和斜顶组合脱螺纹机构代替常用的旋转脱螺纹方式。模具结构合理,运动可靠,产品成型质量好。