Switchgrass as an alternate feedstock for power generation: an integrated environmental, energy and economic life-cycle assessment

An environmental biocomplexity analysis is done on the environmental, energy, economic and technological implications of using switchgrass (Panicum virgatum) to replace coal in power generation. We evaluate cost, environmental impact and net greenhouse gas emissions. In the analysis, alternatives for production and transport are considered. The analysis shows that the most effective technologies for switchgrass preparation are harvesting loose material for hauling and chopping and then compressing it into modules and transporting. The GHG emission mitigation is found to be substantial with the mitigation contribution under cofiring found to be greater per ton of switchgrass than for switchgrass fired alone. This paper also analyzes the implications of switchgrass use under alternative cofiring ratios, coal prices, hauling distances and per acre yields.     

Modeling of Brick Properties for Earth-Based Domes Structures

The use of earth-based materials is becoming increasingly popular, particularly in the rural areas of developing countries. One example is the introduction of an earth dome for low-cost housing in the rural areas of Mozambique [1], although this project is still at a research level. The earth bricks used in building the dome are a type of composite material, consisting of porous soil and possibly cement. The brick properties depend on the proportions of soil, cement and air-filled pores. For economic reasons, the amount of the stiffer and stronger cement phase needs to be minimized. Here, some initial experimental results and the results of a simple numerical model for estimating the stiffness and strength of the bricks are presented. The numerical analyses use a 3D linear elastic finite element program to calculate the effective elastic properties of the brick and a failure stress under uniaxial compression is calculated based on a Drucker-Prager type condition for cohesive materials.     

Analysis of Robustness in the Formulation of Technology Strategy

ABSTRACT

Formulating technology strategy is often complicated by long developmental lead times, extreme uncertainty with respect to the strategic environment, and inevitable changes in key decision makers over the strategic time horizon. The traditional approach to identifying a technological direction or position emphasizes thoroughly analyzing the alternatives and then selecting the best one, usually based on some version of benefit/cost criteria. This article contends that this “optimizing” approach to strategic decision making may be inappropriate in situations characterized by primary uncertainty, highly non-linear interrelationships, and turbulent or chaotic dynamics. Adaptability, resilience, and flexibility are perhaps more appropriate strategic criteria, which, in combination with traditional criteria, suggest a different way of thinking about technology strategy. Measures of robustness are offered as means for assessing the proposed strategic criteria. An analysis of robustness is applied to the formulation of space transportation strategy.     

Technological appropriateness of biomass production in rural settings: Addressing water hyacinths (E. crassipes) problem in Lake Tondano,Indonesia

Climate change has induced an excessive growth of water hyacinths, which produces unintended consequences for the surrounding ecosystem. Particularly, water hyacinth is a major problem throughout the world's tropical zone, which largely consists of rural regions. One way to address the water hyacinths problem is to convert them into biomass. However, typical biomass production technologies have not considered local settings when they are installed in rural areas lacking knowledge and resources. This study aims at assessing the technological appropriateness of biomass production from water hyacinths in rural settings under limited resources and knowledge. This research proposes two scenarios (i.e., high-tech and low-tech) to utilise water hyacinths from Lake Tondano, Indonesia, as the case study. The scenarios consider local settings of communities living around the lake by applying scenario-based design science according to Weiringa's adaptation of the five-stage regulative cycle of Van Strien. The assessment stage employs three levels of technological appropriateness (techno-economic, environmental, social) to assess each scenario for the rural context. Results show that the low-tech design is more appropriate for rural settings around Lake Tondano. Both designs are technically able to resolve the water hyacinths problem; however, the low-tech design is more practical for local communities, addressing the environmental problem while simultaneously boosting socioeconomic developments. In general, the small-scale nature of the more appropriate design applies to other rural areas, with which those areas can utilise various biomass sources while benefitting their socioeconomic situations. Further studies need to assess the technological appropriateness of the appropriate design again based on rural contexts in their location(s).     

Muslim scholars and technological volition

What purpose, according to Muslim scholars, should technological development serve? To answer this question, first we explain the views of seven Muslim scholars who have theorized about technology from an Islamic viewpoint. We then set out Carl Mitcham's fourfold analysis of technology, and summarize the views of philosophers of technology on technological volition. This places us in a position to classify Muslim scholars' opinions on technological development under seven broad headings, namely: meeting human beings' needs, implementation of an Islamic culture and lifestyle, serving human beings, serving nature, understanding the splendor of creation, providing personal and social happiness, and a lack of a volition for technological development.     

Cost–volume–profit analysis under uncertainty: a model with fuzzy estimators based on confidence intervals

In this paper we express the uncertainty existing in cost–volume–profit analysis via a new method that constructs fuzzy estimators for the parameters of a given probability distribution function using statistical data. First we present a fuzzy function for the cost and we search for the optimal solution among alternatives as Finch and Gavirneni [2006, International Journal of Production Research, 44 (20), 4329–4342] do, but here we use fuzzy estimators for the variable costs. As a consequence, we formulate a fuzzy number that represents the difference between the costs of the alternatives. Furthermore, we consider conditions of ‘complete’ uncertainty when a company needs to choose between two products and we express the profits and the risk via fuzzy estimators. Finally, under the same conditions of uncertainty we express the breakeven point when the income equals the total cost.     

Application of risk assessment and decision analysis to the evaluation, ranking and selection of environmental remediation alternatives

A single framework integrating risk assessment and decision analysis methods for evaluating, ranking and selecting preferred remediation alternatives at a contaminated site was developed and demonstrated. The methodology used relies on stakeholder inputs throughout the entire process and employs those inputs to combine the results of multiple risk assessments to arrive at a total impact for each remediation alternative. The total impact values allow the ranking of the alternatives, which in turn, serves as the basis for deliberations among the stakeholders in order to identify the preferred alternative. Six major risk or impact categories were considered in the evaluation of the alternatives: human health and safety, environmental protection, life cycle cost, socio-economics, cultural, archeological and historical resources, and programmatic assumptions.     

Airbus Airframe – New Technologies and Management Aspects

Airframe innovations in all relevant technological fields are important for the development of high performance airframes best to satisfy the market needs. The Airbus “intelligent” airframe is optimized in terms of new materials and advanced design, and implements smart structures technologies step by step. Hence, the competition between technologies (metal vs. composite) is leading to a hybrid airframe solution in the latest Airbus aircraft. This ensures that the best mature innovative technology is used for each specific application. Airbus is in the leading position for application of advanced technologies and has accumulated broad experience in all airframe technologies with all types of structural materials. In order to meet the current and future challenges and to incorporate worldwide best state‐of the‐art technological solutions, cooperation with external suppliers and strategic partners is essential. Increasingly decentralized engineering and manufacturing co‐operations – at an international level – lead to challenging aircraft program and technology management. Therefore, Airbus is intensifying its cooperation with research facilities, equipment, material and structure suppliers based on new Airbus ‐ Supplier cooperation philosophies.     

Energy Planning for Puerto Rico: A Systems Modeling Approach

This study presents various models for energy planning for the year 2000 in Puerto Rico. Puerto Rico depends on imported oil for 99% of its energy needs. The island has many promising energy sources such as biomass (sugar cane bagasse), photovoltaics (solar energy), ocean thermal energy conversion (OTEC), and wind power systems (WPS). These energy sources present some trade-offs in costs, pollution level, and fuel importation, which are studied. Uncertainty in future demand is taken into account. Integer variables representing the possible electricity generation plants are defined. The best compromise solution using the global criterion method for multiple objectives is presented. The proven alternatives such as coal-steam plants, nuclear plants, and biomass steam plants could have political constraints. New technologies such as photovoltaics, OTEC, and WPS possess many uncertainties. Should the cost of these alternatives be less than the electricity generated using oil, a combination of these energy sources would represent the best alternatives to solve Puerto Rico's electricity needs.     

Performance of composite soil reinforced with barley straw

The shortage of low cost and affordable housing in Algeria has led to many investigations into local low cost construction materials. Earth construction is widespread in desert and rural areas but suffers from shrinkage cracking, low strength and lack of durability. The use of natural and vegetable fibres could improve its performance. This paper reports on an experimental study to investigate a composite soil reinforced with chopped barley straw, using four different soils. The effect of fibre length and fibre fraction on shrinkage, compressive strength, flexural strength and shear strength was investigated. Preliminary tests to enhance durability by using different waterproof renders are also briefly reported.     

Advanced method of including housing stiffness into calculation of gear systems

One of the central goals during the design of helical gear systems is the achievement of a well-distributed contact load in the gear mesh. An equal load distribution is a key factor for a high load carrying capacity, the economic use of materials and a long lifetime. Mesh misalignment can be caused by tooth deflections, manufacturing deviations or elastic deformation of the shaft-bearing system and the gearbox housing. Those deformations have to be taken into account during the design process of adequate tooth-flank geometry. Elastic deformations of gearbox housings can be significant, especially in the case of automotive applications with aluminium cases. This paper presents an advanced method of including housing stiffness into the calculation of gear systems. A validation of the approach is carried out by comparing the calculated deformations with measurements of a static test rig of a hypoid gearbox.

Many calculation programs offer the opportunity to analyse the deformation behaviour of the shaft-bearing-housing system. Most of the components in these programs are described by analytic approaches. However, components that are geometrically more complex, like the housing or planet carriers cannot be represented as easily as that by analytic expressions. There are several alternatives to take into account the elasticity of those objects. One way is to model the stiffness of the bores using imported stiffness matrices. These matrices contain the elasticity of the bores itself as well as crossover influences between the bearings. The reduced stiffness matrices may be the result of a static reduction of the geometry using the finite element method (FEM). As state of the art, the reduction is mostly carried out at the centre points of the bearing bores. The proposed advanced method uses the static reduction of geometries on several points at the bores, distributed over the circumference. This approach offers a more detailed modelling of the elastic behaviour of complex geometries within the analytic deformation calculation of gear systems. To validate the advanced approach, the calculation results of the elastic deflections of the shaft-bearing-housing system is compared with measurements of a static test rig. In the course of these comparisons, the influence of different modelling methods of gearbox housings on the accuracy of the calculation results is discussed.

     

Affordable housing and clean technology transfer in construction firms in Brazil

The affordable housing deficit in Brazil is 5.6 million homes. The Main Brazilian housing government program was called “Minha Casa, Minha Vida” from 2009 to 2020. It had little progress in the housing sustainability requirements in the last ten years. For that reason, construction industry has very little changed in terms of innovation. However, this sector has maintained standard production on a large scale. So, the crucial change could become from companies. The clean technology transfer is limited in the Brazilian affordable housing firms. One solution is to analyse this transfer process like a network. Then, it will be possible to evaluate the technological adaptability of these kinds of construction firms. This research aimed to estimate the clean technology transfer between construction firms in Brazil dedicated to building affordable housing. For this, it was identified the 69 construction firms in five cities of Rio Grande do Sul. The cities were Canoas, Caxias do Sul, Passo Fundo, Pelotas, Porto Alegre. Then, a network analysis identified the degree, betweenness, closeness, and density. These studies identify poor performance versus sustainability needs of current low-cost construction. As a result, it identifies the technology transfer capabilities that allow medium-term gains for Brazilian construction firms. Finally, we developed technology transfer indicators to understand the complexity of affordable housing production in Brazil.     

Effect of frequency on high-temperature fatigue crack growth in a silicon carbide reinforced silicon nitride composite

A detailed study on a silicon nitride reinforced with silicon carbide whiskers, Si₃N₄SiC_W, has been undertaken at elevated temperature during static and dynamic loading at increasing K and ΔK respectively. It is shown that cyclic sub-critical crack growth rates are lower than static crack growth rates. The increased crack growth rate during static far field loading is attributed to the stress relaxation of the inter-granular glass phase which allows time-dependent processes to occur ahead of the crack tip which lead to enhanced sub-critical crack growth rates. During cyclic fatigue the glass phase has insufficient time to relax and glassy ligaments are able to bridge the crack wake thereby shielding the crack tip from the full force of the applied load. Also, at particular temperatures, bridging between the surfaces of the crack wake by the inter-granular glass phase results in increased strength and fatigue retardation. The extent of ‘crack wake healing’ is shown to be time and temperature dependent. The viscosity of the glass phase is directly related to the temperature and the bonding force associated with glass phase bridging is observed to reduce with increasing temperature. The results from a previous study at room temperature are compared to those found during this investigation.     

Estimating the regional economic impacts of retiring agricultural land: methodology and an application in California

This report is of a study to assess the efficiency and sustainability impacts of a seed-based technology for pigeonpea in semi-arid central India. The problem of integrating environmental assessment with economic and social impact assessment arises from an artificial separation of the social and natural sciences, and the ‘disciplinization’ of the social sciences. Thus sustainability must be defined in a way that pre-empts the need to integrate results obtained from different approaches. Sustainability assessment then is a dynamic not a static framework. It involves changes in labor requirements, in soil and agro-climatic conditions, and in notions and perceptions of efficiency and profitability with differential social and economic impacts. This approach requires a methodology that uses a combination of techniques — survey research, case study, and rapid/participatory rural appraisals — with the flexibility of adjustment and adaptation during the course of research.     

Sustainable Supply Model Design of Public Rental Housing —Case Study of Chongqing

Public rental housing is an important governmental project. Within the next three years, Chongqing municipal government proposes building 40×10⁶ m² of public rental housing to solve the housing problem for 2 million people. Many problems of sustainability have happened in long-term large-scale construction, including gradually-slow renting progress, the shortage of funds, public rental housing community facilities are retrograde, and the selected sites are at the city’s edge. This paper analyzes the Chongqing public rental housing situation from the perspective of sustainable public rental housing supply, putting forward a sustainable supply model that is suitable for Chongqing, and then calculates their portion.     

我国农村典型砖砌体墙片拟静力试验研究

农村房屋抗震是我国防震减灾工作的重要内容。砖砌体结构作为农村房屋的主要结构形式,如何提高其抗震能力具有重要研究意义。为研究砂浆强度、构造措施和窗洞口对砖砌体抗震性能的影响,该文首先对农村砖砌体房屋常用的几种砂浆和砖砌体进行了抗压强度试验,得到了相应材料及构件的强度参数;然后对不同砂浆强度、不同构造措施和开洞的12个墙片进行了拟静力试验,对比分析了不同因素对墙体力学性能影响。试验结果表明,砂浆强度影响最大,构造措施和开洞影响次之。最后依据试验分析结果为我国农居防震减灾工作提出建议。该文相关研究可为农居的抗震设防、标准制定以及施工提供参考。     

Sustainable Supply Model Design of Public Rental Housing —Case Study of Chongqing

Public rental housing is an important governmental project. Within the next three years, Chongqing municipal government proposes building 40×10⁶ m² of public rental housing to solve the housing problem for 2 million people. Many problems of sustainability have happened in long-term large-scale construction, including gradually-slow renting progress, the shortage of funds, public rental housing community facilities are retrograde, and the selected sites are at the city’s edge. This paper analyzes the Chongqing public rental housing situation from the perspective of sustainable public rental housing supply, putting forward a sustainable supply model that is suitable for Chongqing, and then calculates their portion.     

Application of rough sets for environmental decision support in industry

Practical environmental decision-making in industry is a complex task that often entails a subtle interplay between alternatives and criteria. Quantitative tools are used to aid decision-makers to arrive at rational conclusions. However, conventional decision aids are often limited by the need to define a priori weights for the criteria being considered; identifying the correct weights to use is not a trivial task and has been the subject of considerable research. An alternative approach based on rough set methodology is described in this work. The procedure develops an empirical, rule-based model from example responses derived from an expert panel. The model can then be used for decision-making in cases resembling the example used previously. Rough set theory also provides numerical measures of the reliability of the rule-based model developed. The approach is illustrated with two case studies, the first involving comparison of alternative energy sources, and the second involving the ranking of pollution prevention strategies in manufacturing.     

Polymer‐Fullerene Bulk‐Heterojunction Solar Cells

Solution‐processed bulk‐heterojunction solar cells have gained serious attention during the last few years and are becoming established as one of the future photovoltaic technologies for low‐cost power production. This article reviews the highlights of the last few years, and summarizes today's state‐of‐the‐art performance. An outlook is given on relevant future materials and technologies that have the potential to guide this young photovoltaic technology towards the magic 10% regime. A cost model supplements the technical discussions, with practical aspects any photovoltaic technology needs to fulfil, and answers to the question as to whether low module costs can compensate lower lifetimes and performances.