The effect of lygus bugs (Exolygus prantensis L.) on marketing price of red lentil in Anatolia, Turkey

The aim of this study was to assess the damage commonly known as chalky spot syndrome caused by the lygus bug on red lentil and the negative relation to the resulting marketing price in the commodity market of Sanliurfa, Turkey. Analysis showed that there was significant difference among the content (%) of chalky spot damage (range 1.45–29%) of lentil samples collected from the farmers who brought their crops to sell in the commodity market and this was negatively related to the market price that farmers received. Marketing prices of samples were also found to be significantly affected. The correlation between visually inspected chalky spot damage (%) and that of decorticated and weighted lentils was found to be positive and significant. Marketing prices also were found to be negatively correlated with the results of both inspection methods. Further analysis indicated that regression equations could be used for price estimation of lentil with different ratios of chalky spot. It was concluded that 10% chalky spot can reduce the marketing price from 0.426 to 0.396 $ kg⁻¹ when visually inspected and from 0.438 to 0.358 $ kg⁻¹ when decorticated.     

试论市场经济条件下价格与成本的内涵及其影响因素

在市场经济条件下,资源配置主要采取市场手段,价格和成本发挥着十分重要的作用。文章讨论价格与成本的内涵及其影响因素,指出产品服务的价格受到人们的收入水平、时间、消费者偏好、购买量、产品与服务的性质等诸多因素的影响。     

不利供水条件下水价计算分析研究

根据马克思经济理论 ,分析了水资源价格问题 ,提出了水价不应由平均生产费用来决定而应由不利供水条件下的费用来决定的观点。以水资源投入产出模型为基础 ,对不利供水条件下的水价计算进行了分析研究 ,建立了不利供水条件下的水价计算的矩阵模型 ,为水资源价格的调整提供了理论依据。     

基于ADL-GARCH的电价预测模型及其应用

根据电价序列的特点,首先利用动态计量经济理论构建出一般的自回归分布滞后ADL模型,通过检验统计量修正得到ARMA短期电价预测模型,然后对ARMA模型进行GARCH效应检验,最后根据检验结果构建出ARMA-GARCH的短期电价预测模型.利用新模型对美国加州电力市场的电价进行短期预测,结果表明,新模型能够有效地跟踪实际电价变化的趋势,具有较高的预测精度和良好的适应性.     

Study on the Mechanism of the Effect of Urban Planning System on the Price of Real Estate

Based on the review of progress of research on the influence of urban planning on the price of real estate both at home and abroad, the author analyzes and summarizes the mechanism of the effect of the urban planning system on the price of real estate from three basic levels as strategy planning, implementation planning and planning administration and suggests that the local government should make use of this mechanism to carry out the guidance on the balanced development of urban economy, society and environment in real estate realm.     

Study on Application of Value - at - Risk to the Risk Evaluation of Construction Project Bidding

The value-at-risk(VaR) model is a statistical model to estimate and control financial risk,and used to measure the most probable loss on the next deal stage of financial asset portfolio.Based on the principle of the value-at-risk,in this paper the value-at-risk is to be applied to the risk evaluation of construction project.Assuming the sub-project prices abide by the BQ model are random variable which conform to normal distribution,this paper has built up the portfolio of project according to biding and quoted price of construction project,and adopted the variance-covariance method to measure the value-at-risk of the biding and quoted price in order to provide a feasible risk analysis tool for the evaluation of construction project bidding.     

浅谈砼施工的裂缝产生与防治

现代工程建设中砼已经成为构筑物的主要材料,并占有重要的地位.随着砼的大量应用,也常伴随着各种通病的发生,砼的裂缝已成为砼构筑物的危害之一,特别在桥梁施工中裂缝几乎无所不在.尽管我们在施工中采取各种措施,小心谨慎,但裂缝仍然时有出现.其最主要原因是我们对混凝土的温度应力变化注意不够,在大体积砼中温度应力及温度的控制具有重要的意义.     

Dynamic modulus of elasticity and bending properties of young Taiwania trees grown with different thinning and pruning treatments

The effects of different thinning and pruning methods on the bending strength and dynamic modulus of elasticity (DMOE) of young Taiwania (Taiwania cryptomerioides Hay) were investigated. The average DMOE, modulus of elasticity (MOE), and modulus of rupture (MOR) in the thinning treatments showed the following trend: no thinning > medium thinning > heavy thinning. This indicates that thinning reduces average bending properties. The average DMOE, MOE, and MOR in the pruning treatments showed the following trend: medium pruning > no pruning > heavy pruning. According to this tendency, better average qualities of lumber and specimens were from wood subjected to no-thinning and medium-pruning treatments according to an ultrasonic wave technique and static bending tests. However, most results showed no statistically significant differences among thinning, pruning, and thinning and pruning treatments. The average values of DMOE, MOE, and MOR of visually graded construction-grade lumber were significantly greater than those of below-grade lumber. Moreover, there were very significant positive relationships between density, ultrasonic velocity, DMOE, MOE, and MOR, although the determination coefficients were small.     

Influence of knot area ratio on the bending strength of Canadian Douglas fir timber used in Japanese post and beam housing

A study was conducted to establish the engineering properties and the influence of knot area ratio (KAR)-based grading rules on the bending strength properties of full-size Canadian Douglas fir timber used in Japanese post and beam building construction. In-grade tests were conducted on lumber selected at random from coastal mills in British Columbia, Canada, that manufacture products for the Japanese post and beam housing market. Bending strength and modulus of elasticity test results and KAR-based out-turn information on the 105 × 105mm and 45 × 105mm specimens are presented in this article. The in-grade test results indicate that KAR-based grading rules can be successfully applied to Canadian Douglas fir timber to meet strength property requirements.     

对GB 1927-91《木材物理力学实验方法》中若干问题的商榷

对GB 1927-91《木材物理力学实验方法》中的两个力学性质测试方法做了分析探讨。指出,由于木材的黏弹性,在循环试验中读取下、上限值计算抗弯弹性模量存在偏差及在木材硬度试验方法中关于半压硬度的修正系数对侧面不正确,并提出了改进建议。