Polluting production – environmentally sound alternatives; A general model of production externalities

With the determination of principal parameters of producing and pollution abatement technologies, this paper quantifies abatement and external costs at the social optimum and analyses the dynamic relationship between technological development and the above-mentioned costs. With the partial analysis of parameters, the paper presents the impacts on the level of pollution and external costs of extensive and intensive environmental protection, market demand change and product fees, and not environmental protection oriented technological development. Parametrical cost calculation makes the drawing up of two useful rules of thumb possible in connection with the rate of government in-terventions. Also, the paradox of technological development aiming at intensive environmental protection will become apparent

Network Asymmetries and Access Pricing in Cellular Telecommunications

Network shares and retail prices are not symmetric in the telecommunications market with multiple bottlenecks which give rise to new questions of access fee regulation. In this paper we consider a model with two types of asymmetry arising from different entry timing, i.e. a larger reputation for the incumbent and lower cost of servicing for the entrant as a result of more advanced technology. As a result firms have divergent preferences over the access fee. In case of linear and non-linear prices the access fee might still act as the instrument of collusion, but only if a side-payment is permitted which is generally welfare decreasing. Moreover, in contrast with the European regulatory framework, the access fee on the basis of termination cost might not necessarily be a socially preferable solution.cost asymmetry, brand loyalty, imperfect competition, network interconnection, access fee

Temperature-Induced Shape Memory Characteristics of Epoxy Resin-Based Fabric-Reinforced Composites

Shape memory characteristics of woven glass and carbon fiber fabric reinforced epoxy resin-based composites were assessed in bending mode using a dynamic mechanical analyzer. The reinforcement strongly improved the recovery stress but impaired the bending deformability. Composites with asymmetric fabric lay-up showed better performance when the reinforced section experienced local tension than compression during flexural loading

Microclimate simulation of climate change impacts in a maize canopy

Effects of possible climate modification on maize plant features have been evaluated by using the simulation model of Goudriaan for local climatic conditions and locally measured plant characteristics. Moderate climate modifications were hypothesized. According to the purpose of detecting local impacts of climate change, researches were made on the microclimate of maize canopies. In the energy transport of the plant stand, no shift has been experienced to the direction of the latent heat as it was expected because of the effect of warming up and decrease of precipitation. The changes of stomatal resistance and inside canopy air temperature suggested that the natural water supply will probably not cover the water demand of the plant, if the climate change is more intensive, therefore farmers must prepare to irrigated cultivation and to apply different agro-technical methods to save the water supplies of the ground

Making Exhibitions, Brokering Meaning: Designing new connections across communities of practice

New media museum exhibits often see designers representing the research of expert content providers. Despite perceptions that such exhibits provide museum visitors with a greater depth and range of experience, differences in knowledge and practice between designers and content providers can see content development become an unruly, competitive process in which audience experience, digital mediation, visualisation techniques and meaning become contested territory. Drawing on Etienne Wenger’s theory of “communities of practice”, this paper argues that designers’ advocacy for audiences and distance from exhibition content well positions them to broker interdisciplinary goal setting so that exhibitions observe the representational objectives of content providers and meet the needs and preferences of museum visitors. A wide range of design literature already discusses the pragmatic benefits and ethical importance of user-centered design, while the literature on co-design suggests that designed outcomes are more successful if the design process considers the interests of all stakeholders. These discussions can be compelling, but the inherent challenges in engaging others’ perspectives and knowledge in the design process are less acknowledged, Wenger’s ideas on the social dynamics of group enterprise offering designers valuable insights into the actuality of negotiating designed outcomes with non-designer stakeholders. The paper has two main aspects. The first outlines the theory of communities of practice, focusing on the brokering of knowledge and practice between disciplines. This discussion frames an analysis of the design process for two museum exhibitions. Representing an original application of Wenger’s ideas, the discussion recognises the unique role of the designed artifact in brokering information visualization processes, transcending the actions and intentions of individual stakeholders. While accepting there are successful examples of interdisciplinary exchange in various areas of design, the interpretation of examples via Wenger contributes useful principles to the theorisation of co-design with non-designer stakeholders. Keywords: Information visualization; New media museum exhibits; Multidisciplinary projects; Communities of Practice; Brokering; User-centered design; Co-Design; Etienne Wenger</p

Resonant relaxation in globular clusters

Resonant relaxation has been discussed as an efficient process that changes the angular momenta of stars orbiting around a central supermassive black hole due to the fluctuating gravitational field of the stellar cluster. Other spherical stellar systems, such as globular clusters, exhibit a restricted form of this effect where enhanced relaxation rate only occurs in the directions of the angular momentum vectors, but not in their magnitudes; this is called vector resonant relaxation (VRR). To explore this effect, we performed a large set of direct N-body simulations, with up to 512k particles and ~500 dynamical times. Contrasting our simulations with Spitzer-style Monte Carlo simulations, that by design only exhibit 2-body relaxation, we show that the temporal behavior of the angular momentum vectors in $N$-body simulations cannot be explained by 2-body relaxation alone. VRR operates efficiently in globular clusters with $N>10^4$. The fact that VRR operates in globular clusters may open way to use powerful tools in statistical physics for their description. In particular, since the distribution of orbital planes relaxes much more rapidly than the distribution of the magnitude of angular momentum and the radial action, the relaxation process reaches an internal statistical equilibrium in the corresponding part of phase space while the whole cluster is generally out of equilibrium, in a state of quenched disorder. We point out the need to include effects of VRR in Monte Carlo simulations of globular clusters.Comment: Submitted to Ap