Spatial pricing, optimal location and social welfare with consumer arbitrage

This paper provides a comprehensive comparison of the optimal location, output and welfare of spatial discriminatory pricing by integrating consumer arbitrage into the Hwang and Mai (Am Econ Rev 80:567–575, 1990) model. It shows that the presence of arbitrage creates a significant influence on a firm’s locational choice and thus generates different welfare implications. When the discrepancy between the two markets is small, the optimal location and the resulting social welfare level under discriminatory pricing and mill pricing policies remain the same; however, when the discrepancy between the two markets is large, the two pricing policies yield different optimal locations which make the welfare under discriminatory pricing higher than that under mill pricing, hence reversing the support for anti-trust legislation.     

Heterogeneous duopoly, spatially discriminatory pricing, and optimal location

It is found in the literature that if duopolists produce differentiated products and engage in price competition in a linear city model with elastic demand, the two firms necessarily agglomerate at the market center and this is the unique locational equilibrium, irrespective of the pricing policies charged by the firms. Utilizing a more reasonable market-serving assumption, this paper finds that the firms can be either centrally agglomerated or dispersed depending on the magnitude of the transport rate and the degree of product differentiation. Moreover, if the two firms choose quantity instead of price as their decision variables, the two firms become less likely to stay apart. But if they do, the distance of their locations necessarily shrinks. This paper also examines the locational configuration in the absence of the market-serving assumption and finds that spatial dispersion could be the only location pattern.     

Spatial duopoly under uniform delivered pricing when firms avoid turning customers away

This paper studies a spatial duopoly under uniform delivered pricing when firms do not ration the supply of the good, thus extending to a spatial context the analysis of oligopolistic markets with no rationing. The paper shows the existence of the equilibrium in prices under different tie-breaking rules (TBR) and compare the features of the equilibria found under these rules, thereby allowing to highlight the importance of the choice of the TBR in studying these models. When consumers buy from the nearest firm in case of equal prices (efficient TBR), any symmetric price pair within a given range is a Nash equilibrium, with each firm serving exactly half of the market line. If demand in each local market is equally split between the firms charging the same price (random TBR), the only equilibrium price is the one that gives zero profits to each firm. The degree of competitiveness of the market crucially depends on the TBR. Under the efficient TBR, all (but one) price equilibria deliver positive profits to both firms. Under the random TBR, the market outcome is very competitive in that firms make zero profits. None of the equilibria found under any tie-breaking rule are allocatively efficient.This paper is based on my DPhil thesis at the University of York. I would like to thank Gianni De Fraja, Keith Hartley, Peter Simmons, Catherine Waddams, Xavier Wauthy and participants to the 1998 EARIE and ERSA conferences for helpful comments and discussion. The paper has also been improved by the very useful comments of two referees of this journal. The usual disclaimer applies.Received: January 2001 / Accepted: January 2003     

Atmospheric turbulence with respect to moving ground vehicles

A random-process model is developed for the turbulent wind with respect to a moving ground vehicle. The spatial and temporal variations of the wind turbulence component normal to the direction of motion of the vehicle are considered, and numerical results are given for the power spectral density, cross-correlation, square-root coherence and phase-lag functions.The power spectral density and aerodynamic-admittance functions of side force are evaluated, on the basis of a linear relationship between unsteady side force and turbulence velocity. A numerical example shows that significant excitation of vehicle suspension modes ($\text{f}{}_{\mathrm{n}}\text{\$}\text{?}\text{1}\text{Hz}$) may occur for vehicle speeds exceeding 40 m s^?1, the turbulence energy increasing approximately with the square of mean wind speed.The model gives valuable insight into the structure of turbulent wind with respect to moving vehicles, and should facilitate the interpretation of experimental data. The results also aid rational design of suspension systems for high-speed ground vehicles, to cope with loads due to wind turbulence.     

对砌块建筑存在一些问题的探讨

砌块建筑的推广之所以很难,除了经济因素外,更主要的原因是砌块产品自身的设计问题,再加上实际应用上研究的较少,不能形成完善的施工技术、标准等,所以不能形成大面积推广。作为砌块行业的技术人员,有义务来解决这些问题。所以下面我针对一些具体问题谈点粗浅看法。１砌块建筑刚性屋面与顶层外墙开裂 分析其主要原因是北方在冬季或南方在夏季,因室内外温差较大,外墙与屋面或圈梁不能同时胀缩所致。所以只要能将该部位不同变形的各部分有效隔离,我认为即可解决上述问题。为此对３００ｍｍ的砌块外墙与屋顶及圈梁的结占构造作了参考…     

谈定额计价如何向工程量清单计价转变

介绍了我国目前推行的工程量清单计价的优点，从计价依据、费用组成、价格来源等方面对工程量清单计价与定额计价的差异作了阐述，对促进定额计价向工程量清单计价的转变有一定的指导意义。     

Daily wastewater pollutant dynamics with respect to catchment population structure

To relate population structure and activity to wastewater volume and composition, field trials were conducted at the outlets of two urban catchments that have different population structures (residential-only and mixed). Macropollution and metal micropollution were both considered. In the residential-only catchment, a diurnal pattern with a morning peak (at 10:00) and an evening peak (at 20:00, corresponding to dinner) was observed for all seasons. No difference was observed throughout the year; patterns in summer days, in which daily mobility out of the catchments should be reduced, were similar to those observed in other seasons. For both catchments, N-NH₄ (from urine) and chemical oxygen demand (from urine and grey water) correlated with Cu, Zn, Al, Fe and Mn but not with alkaline earth metals. The observed diurnal pattern is associated with work and school mobility and with the general lifestyle of the population. Such an approach is useful to model expected domestic pollution patterns, with respect to lifestyle changes in the future.     

The decontamination effect of UV radiation with respect to micromycetes

Isolated were pathogenic micromycetes from tap drinking water among which the most typical were Aspergillus niger, Aspergillus flavus, Aspergillus ochraceus, Penicillum cyclopium, Penicillium expansum, Cladosporium cladosporioides. The article has studied inactivation of microscopic fungus by UV radiation. It has also established a series of sensitivity of microorganisms to the effect of ultraviolet. It has been shown that such sanitary-indicative test microorganisms as Escherichia coli, Bacillius subtilis, Candida albicans cannot be used for assessing the degree of water decontamination by UV radiation by the mycological criterion. The stability of micromycetes to UV radiation is an evidence of a necessity to use complex methods of water decontamination.     

Toxicity of urban highway runoff with respect to storm duration

The toxicity of stormwater runoff during various time-based stages was measured in both grab and composite samples collected from three highly urbanized highway sites in Los Angeles, California between 2002 and 2005. Stormwater runoff samples were tested for toxicity using three freshwater species (the water flea Ceriodaphnia dubia, the fathead minnow Pimephales promelas, and the green algae Pseudokirchneriella subcapitatum) and two marine species (the purple sea urchin Strongylocentrotus purpuratus, and the luminescent bacteria Photobacterium phosphoreum using Microtox. Toxicity results varied substantially throughout the storm events for both freshwater and marine species toxicity tests. In general, however, the first few samples were found to be more toxic compared with those collected during later stages of each storm event. In most cases, more than 40% of the toxicity was associated with the first 20% of discharged runoff volume. Furthermore, on average, 90% of the toxicity was observed during the first 30% of storm duration. Toxicity identification evaluation results found copper and zinc to be the primary cause of toxicity in about 90% of the samples evaluated with these procedures. Surfactants were also found to be the cause of toxicity in less than 10% of the samples.     

浅谈工程量清单计价的相关问题

阐述了制定工程量清单的目的和意义,介绍了工程量清单的编制方法和编制原则,比较了工程量清单计价与传统定额计价的区别,表明了工程量清单计价具有的诸多优势。     

施工企业应对工程量清单计价模式的策略

分析了工程量清单计价模式的内涵、特点和优点,阐述了工程量清单计价模式对施工企业的意义,并对施工企业为适应计价模式的变化提出了几点建议和对策,以期指导施工企业正确应对工程量清单计价模式。     

Fail-safe construction on clayey soils with respect to the first limiting state

To provide for fail-safe construction when heavy loads are applied to foundations (pressure of up to 1.0 MPa and more), beds formed from clayey soils should be analyzed with respect to bearing capacity (first limiting state) without restricting ourselves to special cases stipulated in the Construction Rules and Regulations. As a basis of analysis of the bearing capacity of beds, it is proposed to adopt a computational scheme developed by the author where there is no uplift of soil, and the latter is consolidated downward in conformity with the author’s new concept concerning the failure of soil in a bed. Basic notions of the paper were presented at the Gersevanov Lectures on 14 March 2006. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 20–25, September–October, 2006.     

如何完善工程量清单计价招标

论述了我国工程量清单计价招标的基本情况,分析了目前工程量清单计价招标的现状和存在的问题,在此基础上提出了完善工程量清单计价招标可以采取的措施和建议,从而推广工程量清单的应用。     

Alternative approach to credit scoring by DEA: Evaluating borrowers with respect to PFI projects

Private finance initiative (PFI), as a form of public/private partnership (PPP), helps to contract the private sector to governmental projects. In contrast to traditional public financed projects, PFI projects are procured by allowing a private sector entity to take the responsibility to design, build, finance, and operate (DBFO) an asset for a contract period of up to several decades. Moreover, banks are perceived to take the leading role in financing PFI projects. Since project financing involves credit assessment of loan applicants, banks have employed popular credit scoring models to assess their creditworthiness. Although the existing models are useful for credit scoring, new models have to emerge in response to ever-changing business practices. This paper therefore aims at introducing the application of data envelopment analysis (DEA) as an alternative credit-scoring model. Unlike traditional credit-scoring building on a formula where weights to a set of criteria are assigned subjectively, DEA will automatically generate the relative weights for analysis. However, incorporating DEA demands additional considerations, which are discussed in this paper. Finally, examples are demonstrated for illustrating this alterative approach to credit scoring by DEA.     

Evaluation of different treatment processes with respect to mutagenic activity in drinking water

Treatment processes which are applied in The Netherlands during the preparation of drinking water have been evaluated with regard to introduction and removal of organic mutagens as well as halogenated organics. It appeared that the most efficient processes in reducing mutagenic activity were activated carbon filtration and artificial dune recharge. In general these processes were also the most efficient in removing halogenated organics. Using low doses of chlorine dioxide (< 1 mg C10₂/1) for safety disinfection of drinking water, no change or substantial less mutagenic activity than by chlorination (1 mg Cl/1) was found. This counts too for the formation of halogenated organics. Transport chlorination of stored river Meuse water was able to introduce or activate mutagenic nitro organics which have not been found previously. Ozone treatment under field conditions showed mostly a tendency to decrease the activity of organic mutagens. It was also shown that dependent on the water quality and treatment conditions a slight increase of mutagenic activity occurred, but this activity would be reduced by increasing the ozone dose. It seems possible to optimalize the ozone treatment conditions regarding the level of ozone dose and the contact time to avoid an increase of mutagenic activity. Futhermore it was shown that when a mutagenic raw water source was used a proper combination of treatment processes is able to produce drinking water in which no mutagenic activity could be detected under the test conditions. Finally it is stated that before far-reaching decissions with respect to use mutagenicity data for a selection of water sources or treatment processes will be made, more information on the relation mutagenic activity from drinking water and effects on human health should become available.     

Experimental investigations of the performance of piles prestressed with respect to the soil

Results are presented for experimental investigations of models of a new generation of single piles prestressed with respect to the soil with controllable in-service reliability.     

Simulating space heating demand with respect to non-constant heat gains from household electricity

It is crucial to perform energy simulations during the building process to design a building that meets requirements regarding low energy use. In a low energy building, internal heat gains such as excess heat from household electricity are a large part of the heat balance of the building. The internal heat gains depend on the occupants and are not constant, although they are often assumed constant in simulations of space heating demand. This article analyses how different usage patterns of household electricity affects simulated space heating demand. Parametric studies of energy use-related parameters were done to study the influence from different designs. The results show that the different energy use patterns affect the space heating demand, especially in low energy buildings and during the colder parts of the year. To make accurate energy simulations of low energy buildings, household electricity use patterns should be taken into account.     

Quantitative microbial risk assessment with respect to Campylobacter spp. in toilets flushed with harvested rainwater

In light of increasing pressures on water supplies in some areas, water demand management and water conservation techniques are likely to become increasingly prevalent. In‐house systems using alternatives to mains supplies for nonpotable uses present one such option for reducing potable water demand. This paper, through a formal desk‐based health impact assessment (HIA) and quantitative microbial risk assessment (QMRA), examines one of the possible health implications (Campylobacter infection from toilet flushing) resulting from the use of rainwater harvesting in the home in the United Kingdom. This is investigated using data from the literature and a hypothetical case study population of over 4000 people (based on data for the ‘average’ population in England), with the results being expressed as disability‐adjusted life years (DALYs) (on an annual basis) and placed in context of the ‘tolerable’ risk from drinking‐water supplies.     

Estimating compressive and flexural strength of travertines with respect to laminae-orientation by geomechanical properties

Bulletin of Engineering Geology and the Environment - Travertine is an anisotropic rock considered as one of the most popular stone materials in the building industry. Due to its bedding and...