Assessment for Salinized Wasteland Expansion and Land Use Change Using GIS and Remote Sensing in the West Part of Northeast China

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da’an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.     

繁昌县后备土地资源多宜性评价

合理评价后备土地资源适宜性是有效进行后备土地资源的开发利用和农业结构调整的前提。以繁昌县后备土地资源为例,以区域自然与人为因子对其进行初步筛选,在此基础上建立适宜性评价指标体系,结合生态位适宜度理论构建多宜性评价模型,运用加权平均模型和限制因子模型,对后备土地资源评价单元耕地、园地和林地3种土地利用类型的生态适宜度及限制性生态因子进行评价。结果表明:(1)繁昌县59.38%的后备土地资源不能进行开发,能够开发且对生态环境影响较小的后备土地资源为387.03hm2;(2)繁昌县生境环境较为良好,对各土地利用类型的适宜性较强;单一土地利用类型评价中后备土地资源生态位适宜度值最大值为0.966 5。其中,耕地适宜性最高,林地次之,园地最低;(3)多宜性评价表明繁昌县后备土地资源中耕地适宜性面积最大,林地次之,园地最小;(4)限制繁昌县后备土地资源开发利用的生态因子主要为:排水条件、pH值、障碍层深度。为改善后备土地资源开发利用的生境条件,今后应重视土地质量管理,加强农田水利设施建设,使其适合开发利用的需要。     

以生态学原理为指导建设和管理生态旅游--平遥县生态旅游建设研究

在理解生态旅游涵义，综述当前生态旅游研究进展的基础上，本文探讨如何以生态学原理为指导建设和管理生态旅游，并以山西省平遥县为例，提出发展生态旅游的途径，即注重生态旅游区规划和景观生态设计，建立生态补偿机制，实施生态工程，加强生态管理等措施，促使平遥县由农业大县转变为生态旅游大县。     

Posture and belt fit in reclined passenger seats

Abstract

Objective: Highly reclined postures may be common among passengers in future automated vehicles. A laboratory study was conducted to address the need for posture and belt fit in these seating configurations.

Methods: In a laboratory vehicle mockup, the postures of 24 men and women with a wide range of body size were measured in a typical front vehicle seat at seat back angles of 23°, 33°, 43°, and 53°. Data were gathered with and without a sitter-adjusted headrest. Posture was characterized by the locations of skeletal joint centers estimated from digitized surface landmarks.

Results: Regression analysis demonstrated that the pelvis rotated rearward and lumbar spine flexion decreased with increasing recline. The lap portion of the 3-point belt was more rearward relative to the pelvis in more-reclined postures, and the torso portion crossed the clavicle closer to the midline of the body. Regression equations were developed to predict posture and belt fit variables as a function of passenger characteristics, seat back angle, and the use of the headrest.

Conclusions: Spine posture changes as the torso reclines in an automotive seat, and belt fit is altered by the change in posture. The results can be used to accurately position crash test dummies and computation human models and to guide the design of belt restraints.     

Implications of head and neck restraint test repeatability for specification improvement

Objective: Since 2005, National Association for Stock Car Auto Racing, Incorporated (NASCAR) drivers have been required to use a head and neck restraint system (HNR) that complies with SFI Foundation, Inc. (SFI) 38.1. The primary purpose of the HNR is to control and limit injurious neck loads and head kinematics during frontal and frontal oblique impacts. The SFI 38.1 performance specification was implemented to establish a uniform test procedure and minimum standard for the evaluation of HNRs using dynamic sled testing. The purpose of this study was to evaluate the repeatability of the current SFI 38.1 test setup and explore the effects of a polyester seat belt restraint system.

Method: Eight sled tests were conducted using the SFI 38.1 sled test protocol with additional test setup constraints. Four 0° frontal tests and 4 30° right frontal (RF) oblique tests were conducted. The first 3 tests of each principal direction of force (PDOF) used nylon SFI 16.1 seat belt restraint assemblies. The fourth test of each PDOF used polyester SFI 16.6 seat belt restraint assemblies. A secondary data set (Lab B Data) was also supplied by the HNR manufacturer for further comparisons. The International Organization for Standardization (ISO) 18571 objective comparison method was used to quantify the repeatability of the anthropomorphic test device (ATD) resultant head, chest, and pelvis acceleration and upper neck axial force and flexion extension bending moment time histories across multiple tests.

Results: Two data sets generated using the SFI 38.1 test protocol exhibited large variations in mean ISO scores of ATD channels. The 8 tests conducted with additional setup constraints had significantly lower mean ISO score coefficients of variation (CVs). The Lab B tests conducted within the current specification but without the additional test setup constraints had larger mean ISO score standard deviation and CV for all comparisons. Specifically, tests with the additional setup constraints had average CVs of 3.3 and 2.9% for the 0° and 30° RF orientations, respectively. Lab B tests had average CVs of 22.9 and 24.5%, respectively. Polyester seat belt comparisons had CVs of 5.3 and 6.2% for the 0° and 30° RF orientations, respectively.

Conclusion: With the addition of common test setup constraints, which do not violate the specification, the SFI 38.1 test protocol produced a repeatable test process for determining performance capabilities of HNRs within a single sled lab. A limited study using polyester webbing seat belt assemblies versus the nylon material called for in SFI 38.1 indicates that the material likely has less effects on ATD upper neck axial force and flexion extension bending moment time histories than the test setup freedom currently available within the specification. The additional test setup constraints are discussed and were shown to improve ATD response repeatability for a given HNR.     

垦利县土壤-人类-环境相互关系及可持续发展研究

从垦利县自然环境特点、土壤主要特征以及土壤资源的利用入手、分析探讨了土壤－人类－环境的相互关系,探明了土壤－人类－环境恶化的客观原固和人为影响。在此基础上,提出了促进土壤－人类－环境可持续发展的措施。     

三峡库区生态经济区用地结构演变及驱动机制——以梁平县为例

根据1999～2007年土地利用统计、社会经济资料,借助信息熵原理及马尔科夫转移矩阵模型对梁平县土地利用结构动态演变进行了实例分析。结果表明,梁平县土地利用结构信息熵H经历了3个阶段：1999～2002年持续上升阶段、2002～2003年急速回落阶段及 2003～2007年波动阶段,土地利用结构无序程度发展态势不明显,均衡度变化与信息熵相似。用地类型主要由耕地转向林地、交通用地、居民点及工矿用地。定性分析了影响该县用地结构动态演变的政治经济政策,并利用主成分分析法对经济社会主要驱动因子进行了分析与探讨,得出影响该县用地结构动态演变的主要驱动力为：政治经济政策、经济发展。最后依据分析结果对梁平县未来发展做出定位：特色农业县--重点发展农林产品加工及文化生态旅游。     

Long-term environmental monitoring of persistent organic pollutants and metals in a chemical/petrochemical area: human health risks

Organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs), as well as some metals are periodically monitored in soil and vegetation samples collected in Tarragona County (Spain). We here report the temporal trends of the concentrations of the above pollutants between the initial survey (2002) and that recently (2009) performed. The area under evaluation was divided into 4 sections (chemical, petrochemical, urban/residential and unpolluted). In general terms, urban soils presented the highest concentrations of PCDD/Fs, PCNs and PAHs, confirming that traffic is a very important emission source of these pollutants. In addition, substantially higher levels of PAHs and some metals were found in vegetation samples from the petrochemical complex. The assessment of health risks of these contaminants indicated that the current concentrations of micropollutants did not mean additional non-carcinogenic or cancer risks for the population living in the zone.     

最小数据方法在舟曲县生态补偿中的应用

弄清补偿标准和新增生态系统服务供给量之间的关系是生态补偿研究中的关键问题.舟曲县现有的补偿是静态补偿,补偿标准低,没有很好地达到改善生态环境的目的.本文基于最小数据方法,以耕地和林地提供的水土保持量的差异表征生态系统服务,通过提供单位水土保持服务的机会成本的空间分布,推导出舟曲县森林水土保持的供给曲线,从而将补偿标准和新增水土保持服务的供给联系起来.同时对比了3种补偿标准下的退耕比例、生态补偿总资金需求和新增水土保持量.研究表明生态补偿在理论上可以提供舟曲县的水土保持能力.随着补偿标准的提高,新增水土保持量也在增加.当补偿标准为250元/亩时,退耕比例仅为8.26%,生态补偿总资金需求为1 930.03万元,新增水土保持量为4.69×104t;当补偿标准提高到518.63 元/亩时,退耕比例增加到49.54%,总资金需求为23 184.26万元,新增水土保持量为2.83×105t;当补偿标准增加到995.65 元/亩时,退耕比例可达到98.79%,总资金需求为87 340.95万元,可新增水土保持量达到5.65×105t.     

基于生态足迹的香格里拉县生态安全趋势预测

香格里拉县是世界自然遗产三江并流地区的核心部分,其生态安全备受世人关注。基于生态足迹模型分析了香格里拉县2002~2008年的生态足迹及生态承载力的变化过程。结果表明:该县人均生态足迹从0.549ghm2上升到0.717 ghm2,年均增加4.37%;生态承载力从0.768 8 ghm2下降到0.621 7 ghm2,年均下降2.73%。根据生态压力指数分析,2002~2004年属于生态较安全期,2005~2007年属于生态稍不安全期,从2008年起生态盈余成为生态赤字进入较不安全期。运用灰色系统方法预测了2009~2013年生态压力指数的动态变化,预测从2011年起已进入生态很不安全期,到2013年已接近生态极不安全期。说明生态安全恶化有加速的趋势,恢复和保护生态环境刻不容缓。本研究为香格里拉县可持续发展提供了依据,并实证了生态足迹模型在高山峡谷地区的应用。