548 research outputs found

    Game-theoretic insights into the role of environmentalism and social-ecological relevance: A cognitive model of resource consumption

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    The environmental and social attitudes of consumers can greatly affect the consumption of common-pool resources by the whole society – as demonstrated by many experimental and theoretical studies. Rooting in the current knowledge of consumer psychology, and employing the game-theoretic modelling framework, we formalise the decision making process of individuals about their resource consumption levels depending on their level of environmental concern, and relative importance placed on social and ecological information. Our model demonstrates, in a stylized fashion, how profound preference to social information can help avert free-riding behaviour and result in globally stable resource consumption dynamics. This avoids the “Tragedy of the Commons”, leading to affluence in the resource stock as well as in the individual consumption. Furthermore, we find that heterogeneity of the levels of individuals’ environmentalism promotes free-riding, whereas heterogeneity in relative information preferences helps avoiding tragedies. Our analysis demonstrates that accounting for heterogeneity of consumers and their social relationships can yield additional insights regarding to what kind of societies may have better chances to ensure sustainable consumption of a natural resource

    Floods and flood management and its socio-economic impact on Pakistan: A review of the empirical literature

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    Flood is one of the most damaging natural disasters as the recent floods have shown their serious impact on Pakistan. Flood control and regulation policies are essential to reduce the risks of economic downturn, a threat to human existence, and to sustain the ecology. The severity of flood catastrophe activities represents a constant and severe issue in the world. Floods are rising year by year in severity and duration, causing negative impacts on the social and economic conditions of the nation concerned. While the frequency of floods cannot be avoided, their adverse impacts can be considerably reduced by adopting careful planning and efficient training. This paper reviews the socioeconomic impact of floods, and the existing condition of flood control policies outlines the flood protection problems and discusses opportunities for successful and efficient flood control in Pakistan. The paper also intends to propose several suggestions for efficient and sustainable flood control in Pakistan

    Analysis of metallurgical aspects and their role in processing and performance of superalloys: A review

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    Metallurgical processing factors like kinetic and thermodynamic parameters which are essential for modeling of γ′ phase precipitation have been studied. These parameters include γ′ solvus temperature, Gibbs free energy of dissociation of the γ matrix to form γ′, nucleation rate, effective diffusivity and interfacial energy. Nucleation methods and effect of cooling rate on the final phase structure have been analyzed. Co based  superalloys have been studied as a potential and promising material for aerospace applications. Effect of microporosity on the mechanical properties of Superalloys has also been analyzed.Keywords: Superalloys, Precipitation, Solidification, Gamma prime, Microsegregation, Microporosity

    Studying the effect of variation in volume fractions of carbon fibres on mechanical and electrical properties of copper based composites

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    Metal Matrix Composites (MMC) belong to a class of weight efficient structural materials that are becoming popular in engineering applications especially in electronics, aerospace, aircraft, packaging and various other industries. This study focuses on the effect of varying carbon fiber wt. % on the mechanical properties of the Cu-C composite. The carbon fibers were coated with copper by electroless plating in order to increase the wettability of fibers with the copper matrix. Four compositions of copper based composite were developed by varying amount of carbon fibers. The yield strength decreases with increasing fiber size while the ultimate  tensile strength increases with increasing fiber size. Rockwell hardness test showed an increasing trend of hardness for increasing carbon fibers. The conductivity of Cu-C composite decreases by increasing carbon fibers content. Wear rate of Cu-C composite increases when carbon fiberscontent increases in the composite. SEM/EDX analysis revealed the size and distribution of fibers and indicated the fracture phenomenon.Keywords: Copper based Composites, Mechanical, Electrical and Wear Properties, Microstructur

    Optimal Growth, Renewable Resources and Sustainability

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    We study a growth model for a single resource-based economy, as an infinite-horizon op-timal control problem. The resource is assumed to be governed by the standard model of logistic growth, and is related to the output of the economy through a Cobb-Douglass type production function with an exogenously driven knowledge stock. The problem involves unbounded controls and the non-concave Hamiltonian. These preclude direct application of the standard existence results and Arrow’s sufficient conditions for optimality. We transform the original optimal control problem to an equivalent one with simplified dy-namics and prove the existence of an optimal admissible control. Then we characterize the optimal paths for all possible parameter values and initial states by applying the ap-propriate version of the Pontryagin maximum principle. Our main finding is that only two qualitatively different types of behavior of sustainable optimal paths are possible de-pending on whether the resource growth rate is higher than the social discount rate or not

    The Experience of International Students and Institutional Recommendations: A Comparison Between the Students From the Developing and Developed Regions

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    Prior studies on the experiences of international students in China have mostly focused on their academic, sociocultural, and accommodation experiences. Hence, student health and safety, discrimination, and the services by the International Student Office (ISO) have remained unexplored. Moreover, due to the motivational differences between the students from developing and developed regions, a study that samples students from both regions may depict an exact picture of the experience of international students. Therefore, the objective of this study is to examine the influence of the dimensions (including those dimensions that have been ignored) of the experience of international students on their satisfaction. In addition, we make recommendations regarding Chinese institutes for future students based on a comparison between the students from developing and developed regions. Using hierarchical regression analysis, this study reveals that educational and non-educational experiences vary among students from different regions. Therefore, based on developing (e.g., Asia and Africa) and developed (e.g., America, Europe, and Australia) regions, important recommendations are discussed regarding how educational institutions and the Chinese government could best allocate resources and introduce policies to improve the experience of international students

    Fragmentation cross sections of Fe^{26+}, Si^{14+} and C^{6+} ions of 0.3-10 A GeV on CR39, polyethylene and aluminum targets

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    New measurements of the total and partial fragmentation cross sections in the energy range 0.3-10 A GeV of Fe^{26+}, Si^{14+} and C^{6+} beams on polyethylene, CR39 and aluminum targets are presented. The exposures were made at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The CR39 nuclear track detectors were used to identify the incident and survived beams and their fragments. The total fragmentation cross sections for all targets are almost energy independent while they depend on the target mass. The measured partial fragmentation cross sections are also discussed.Comment: 4 pages, 5 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200

    Cosmic ray abundance measurements with the CAKE balloon experiment

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    We present the results from the CAKE (Cosmic Abundance below Knee Energy) balloon experiment which uses nuclear track detectors. The final experiment goal is the determination of the charge spectrum of CR nuclei with Z > 30 in the primary cosmic radiation. The detector, which has a geometric acceptance of \~ 1.7 m2 sr, was exposed in a trans-mediterranean stratospheric balloon flight. Calibrations of the detectors used (CR39 and Lexan), scanning strategies and algorithms for tracking particles in an automatic mode are presented. The present status of the results is discussedComment: 5 pages, 3 figures, proceeding to 29 ICRC, 2005, Pune Indi
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