Local ownership of ethanol plants: What are the effects on communities?

The rapid expansion of ethanol plants across the U.S. state of Iowa has fueled debate about the burdens and benefits of local (in-state investors) versus non-local ownership of biorefineries. Central to these concerns is the extent to which non-local, absentee owners might reap the benefits of the ethanol industry at the expense of local communities. A key argument within the rural development literature is that local ownership of firms has a positive effect on the long-term well-being and sustainability of the communities in which they are situated. This literature asserts that firms operate at different scales, with local firms embedded within local supply chains and institutions, and non-local firms embedded within national and international networks and institutions. Conversely, there is a growing body of work within the alternative agrifood systems literature that cautions against the ‘local trap’; the assumption that the local scale is inherently good and therefore advantageous. Despite this broader debate, the literature on local ownership and renewable energy remains limited. This paper addresses this gap by drawing on case study research of the community effects of ethanol plant ownership structure from the perspective of community leaders. My findings suggest that differences between the structure and effects of local versus non-local ownership of firms on communities are rather more ambiguous than the literature asserts. Therefore, assumptions about the benefits of local ownership may be overstated and concepts of ‘local’ and ‘non-local’ may be inadequate for considering firm outcomes on the civic welfare and socioeconomic well-being of a community.     

COMMUNITY SOLAR HEATING SYSTEM: A CASE STUDY FOR JORDAN

In this paper a study was carried out on the feasilibity of using solar energy for a direct space heating of a residential complex in Jordan, constructed from special building materials to reduce heat losses. A computer simulation was carried out for the solar heating system and indicated that an 81 m² of collecting area was the most cost effective, giving an annual solar contribution to the total annual heating load of 0.987. The remaining portion of the load is to be supplied by an auxiliary system. The economical analysis gave a net saving of almost 27000 J.D over a period of twenty years.     

Thermal analysis in coated cutting tools

This work studies the heat influence in cutting tools considering the variation of the coating thickness and the heat flux. K10 and diamond tools substrate with TiN and Al₂O₃ coatings were used. The numerical methodology utilizes the ANSYS^® CFX software. Boundary conditions and constant thermo physical properties of the solids involved in the numerical analysis are known. To validate the proposed methodology an experiment is used. The TiN and Al₂O₃ coatings did not show satisfying results during a continuous cutting process. It showed a slight reduction in the heat flux for the 10 (µm) TiN and Al₂O₃ coatings.     

The nature of virtual communities

The impressive development of electronic communication techniques has given rise to virtual communities. The nature of these computer-mediated communities has been the subject of much recent debate. Are they ordinary social groups in electronic form, or are they fundamentally different from traditional communities? Understanding virtual communities seems a prerequisite for the design of better communication systems. To clarify this debate, we will resort to the classical sociological distinction between small traditional communities (based on personal relations) and modern social groups (bound by looser, more impersonal links). We will argue that the discussion about virtual communities is often vitiated by a simplistic assimilation to traditional communities, whereas they may be in fact quite different and much more impersonal. Virtual communities are often bound by reference to common objects or goals, and not by personal relations. In this respect, virtual communities are just another example of a long-term evolution of modern society toward more abstract social relationships.     

Writing power into online discussion

This article considers the way in which control of interaction emerges as a function of personal agency and external factors in a group of students engaged in online asynchronous text-based communication in a distance education program. It is structured around the argument that control is partly related to the power that individuals have to give effect to their wishes, but also acknowledges that this sense of agency is always in relation to the powers of others and more structural constraints. A picture emerges of the choices students make in deciding when to initiate discussion and respond to others, and about decisions concerning whose messages they would read and when. The impact of other students, of online groups, and instructors seems to play an important role in determining how participants participate in online interaction. Consideration of broader issues shows how the context in which students engage in interaction impacts the nature and extent of that interaction. The article concludes that being aware, and taking advantage of the socially grounded nature of online interaction provides the basis from which educators can act to ensure that interaction in online learning communities is enabling for the learning of all students.     

Faceless students, virtual places: Emergence and communal accountability in online classrooms

A pedagogical problem growing out of virtual classrooms is the temptation to act without communal accountability, the reciprocal commitment among individuals to maintain the health of their interconnections. Drawing on an ethnographic study of a fully online composition class, I argue that teachers can encourage accountability within virtual sites by conceiving of the online classroom as an emergent phenomenon. The relationships and activities among language, physical reality, and interpretant provide the matrix out of which place organizes itself. This ecological orientation provides local and systemic strategies for fostering communal health. I begin my exploration of online place by describing the value of complex systems theory and emergence for conceptualizing place. Next, I describe the roles of language, physical reality, and interpretant, pointing out the contribution of each to the configuration of virtual place and to communal accountability. Then, I focus on the emergence of place, which reorganizes language, reality, and interpretant, opening up a new dimension to communal accountability.     

P2P群体管理体系结构的搜索优化和自组织性研究

资源搜索和节点管理一直是非结构化Peer-to-Peer （P2P）网络研究的热点.很多不同的搜索策略和分组方案在面临高转换率,freeriding和whitewashing等特殊安全问题时将无法达到原有的性能和效率.文章提出了一个开放的具有抵抗上述特殊问题的群体管理体系结构.主要工作包括：（1）一个新的群体管理体协结构及对应的协议和双层树结构：（2）基于缓存的捷径技术和关键拓扑群体分组技术来优化搜索策略.性能评估表明提出的体系结构具有更好的搜索性能、开放性和对抗特殊问题的能力.     

智能IC卡支付的电子商务系统的研究和实现

电子支付形式是电子商务系统的关键 ,本文提出了一种小额支付系统的体系结构和加密方法 ,分析了该体系结构的安全性 ,并在安全性满足中国人民银行有关规范的基础上实现了该体系结构     

有限素整数域椭圆曲线密码体制基于代数几何快速算法设计

椭圆曲线公钥密码体制(ECC)具有最高的位安全强度,将是对现有公钥密码体制的替代。文章描述了代数几何与ECC的数学基础,讨论了椭圆曲线离散对数困难性问题及ECC在电子商务中的安全应用。利用仿射坐标与射影坐标的映射关系,设计了一种有限素整数域上ECC快速算法,使得ECC在电子商务中实际安全应用成为可能。     

基于IC卡的电子支付模型研究

电子支付技术是电子商务中的核心技术,也是目前制约电子商务发展的一个根本性问题。文章就电子商务中的电子支付技术进行了探讨,以SET协议为基础,提出了三种参考模型,并对这三种电子支付模型进行了对比分析,给出了这三种电子支付模型的优缺点和共同点。