ECONOMIES ASSOCIATED WITH SIZE OF WATER UTILITIES AND COMMUNITIES SERVED IN NEW HAMPSHIRE AND NEW ENGLAND1

ABSTRACT. This study investigates economies associated with size of New England water utilities. Regression analysis techniques were applied to annual water cost and production data reported in the American Directory of Water Utilities (1968-1969). Modest economies of size in the production of water were found. Because in large communities more water is used per person, total cost increases at a slightly faster rate than population increases, but per unit costs of producing water decline. Substantial economies occurred when the number of customers was held constant and volume of water per customer increased. This study indicates possible economies when two or more of the many very small utilities combine activities to form a larger unit and by encouraging present customers to use more water.     

Electricity consumption and economic growth nexus in Zimbabwe revisited: fresh evidence from Maki cointegration

This study explores the relationship between electricity consumption, real gross domestic product per capita and carbon dioxide emissions in Zimbabwe. To achieve this, the study set off by examining the stationarity properties of the variables under review with the Zivot-Andrews (1992 Zivot, E., and D.W.K. Andrews. 1992. Further evidence on the great crash, the oil-price shock, and the unit-root hypothesis. Journal Of Business and Economic Statistics 10:251-270. doi: http://dx.doi.org/10.2307/1391541.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) unit root test that accounts for a single structural break. Subsequently, Maki (2012 Maki, Daiki. 2012. “Tests for Cointegration Allowing for an Unknown Number of Breaks.” Economic Modelling 29 (5): 2011–15. https://doi.org/10.1016/J.ECONMOD.2012.04.022 [Google Scholar]) cointegration test, which accounts for multiple structural breaks, is applied for equilibrium relationship between the variables under review while the long run regression of dynamic ordinary least square (DOLS) is employed for long-run coefficients as estimation procedures. In order to account for the direction of causality flow, the Toda-Yamamoto (1995 Toda, H Y.., and Taku Yamamoto. 1995. Statistical inference in vector autoregressions with possibly integrated processes. Journal Of Econometrics 66 (1–2):225–50. doi: 10.1016/0304-4076(94)01616-8.[Crossref], [Web of Science ®] , [Google Scholar]) causality test is used for annual frequency data set spanning from 1971–2014. Empirical evidence from the Maki cointegration test shows that there exists a long-run equilibrium relationship between electricity consumption, carbon dioxide emissions and real gross domestic product per capita over the sampled period. The long-run regression suggests that there exist a positive statistically significant relationship between real income and electricity consumption. Thus, corroborating the electricity-led growth hypothesis. This result is supported by the causality test, as one-way causality is observed running from electricity consumption to real gross domestic product. Thus, this is suggestive to government administrators and policymakers that the Zimbabwean economy is electricity dependent. However, there is a tradeoff for environmental quality. As the increase in electricity consumption increases carbon dioxide emissions. The need for diversification of Zimbabwe energy portfolio to cleaner and environmentally friendly energy sources is recommended, given the world global consciousness for cleaner energy consumption.     

Sediment Availability and Erosion Rates on Off‐Highway Vehicle Trails in the Ouachita Mountains,USA

Factors influencing sediment availability are assessed and erosion rates are quantified for an off‐highway vehicle (OHV) trail system in the Ouachita Mountains of Arkansas. As of May 2012, the Wolf Pen Gap trail system included 77.0 km of "trails" which consist of county roads; open and closed Forest Service roads; and open and closed OHV trails. For a given trail length, the sediment volume available to be eroded is determined by bare trail width and sediment depth. Four condition types are defined that group trail sections based on statistically different trail widths or depths. Trail construction method appears to influence sediment availability differences more than erosion potential (as indexed by trail slope gradient and length). The range for annual trail erosion rates is estimated as 75 and 210 tonne/ha/yr. The high and low rates are obtained using two independent methods. The 210 tonne/ha/yr rate is computed from mean sediment capture at 30 sediment traps installed for 0.5–1.0 year. The 75 tonne/ha/yr rate is computed assuming all available trail sediment measured in a one‐time sampling is eroded over the next year. We argue in support of this assumption and suggest both rate values may be conservative. Trail erosion rates and sediment trap observations indicate frequent trap cleanout will be needed to continue sediment capture from All Terrain Vehicle trails.     

Uncertainty Analysis In Dissolved Oxygen Modeling in Streams

Uncertainty analysis in surface water quality modeling is an important issue. This paper presents a method based on the first-order reliability method (FORM) to assess the exceedance probability of a target dissolved oxygen concentration in a stream, using a Streeter–Phelps prototype model. Basic uncertainty in the input parameters is considered by representing them as random variables with prescribed probability distributions. Results obtained from FORM analysis compared well with those of the Monte Carlo simulation method. The analysis also presents the stochastic sensitivity of the probabilistic outcome in the form of uncertainty importance factors, and shows how they change with changing simulation time. Furthermore, a parametric sensitivity analysis was conducted to show the effect of selection of different probability distribution functions for the three most important parameters on the design point, exceedance probability, and importance factors. Note: This version was published online in June 2005 with the cover date of August 2004.     

我国石油消费现状及其战略思考

石油是支撑经济发展和国防现代化的基本能源之一。在当今国际社会中 ,石油已成为世界政治、经济、军事和外交斗争的特殊武器 ,成为一国经济发展、社会稳定以及国家安全的重要保障条件。我国目前石油供需形势严峻 ,主要表现为 :石油储量接替准备不足 ,老油田稳产面临严峻形势 ;需求增长过快 ;对外依存度较高 ;运输和贮存能力较小等方面。石油的安全及其保障问题关系到我国的经济安全和国家安全 ,因此 ,有必要研究我国的石油消费现状及发展战略。笔者针对我国的石油消费现状 ,分析了目前我国石油战略中存在的问题 ,探讨了我国的石油战略。     

旅皖国内旅游者消费结构初探

分析比较了2001年旅皖国内旅游者消费结构的特点和原因,认为国内旅游者消费结构以刚性旅游消费为主,弹性旅游消费比重较低;普遍具有较强的住宿、餐饮消费偏好,购物、娱乐是消费弱项.为引导旅游者关注弹性消费,实现消费结构合理化,促进安徽省旅游业产业结构的优化升级和经济效益的持续增长,应构建形式多样的大众娱乐设施,丰富旅游景区的娱乐功能,提升旅游商品档次和销售能力,建设多功能购物街,多方位营造安全的旅游消费环境.     

走向生态文明之路

本文提出了防止生态破坏,走向生态文明的几点建议。     

MODELING TO EVALUATE MACROPHYTE INDUCED IMPACTS TO DISSOLVED OXYGEN IN A TAILWATER RESERVOIR1

ABSTRACT: Effects of aquatic macrophytes are not considered in most standard water quality models. This study used field measurements and water quality models to help determine the effects of aquatic macrophytes on dissolved oxygen (DO) concentrations in a shallow tailwater reservoir. Installation of a hydropower plant and macrophytes (primarily Potamogeton and Chara) in a large shallow portion of the lake are possible causes of reduced DO levels in the tailwater reservoir. A water quality model (WASP5) was used to quantify the various DO sources and sinks and to evaluate the effects of the hydropower operations on DO levels in the lake. It was found that the macrophytes in Lake Ogallala had a significant effect on the DO levels in the lake. At an average macrophyte density of about 6,360 g/m² (wet weight) in 2000, the DO fluctuated daily from about 3 mg/l to about 12 mg/l. At an average macrophyte density of about 2,120 g/m² (wet weight) in 2002, the DO fluctuated from about 5 mg/l to about 9 mg/l daily. The model predicted that the DO would remain near 5 mg/l without macrophytes. The photo‐synthetic and respiration rates developed in the model (4.4 mg/g‐hr and 1.4 mg/g‐hr, respectively) agree well with literature values.     

分光光度法测定测田废水中的COD_(Cr)

为了快速监测油田废水中的化学需氧量ＣＯＤＣｒ,因此采用ＴＬ－１（Ａ）型污水ＣＯＤＣｒ速测仪进行加热催化消解,然后再用分光光度比色法测定ＣＯＤＣｒ,实验中进行了方法的准确度、精确度及Ｃｌ－影响实验,并与标准的重铬酸钾法进行了对比实验,结果说明分光光度法简单快速、重现性较好、准确度较高,对同一产品的测定结果与重铬酸钾法非常一致。因此,本方法可用于油田废水中的ＣＯＤＣｒ监测。     

COD分光光度法与标准方法对比实验

ＣＯＤｃｒ分光光度快速测定法具有简便，快速，节能，省试剂等优点。其测定结果与标准方法之间有良好的可比性，最低检测限为５．０ｍｇ／ｌ 。