THE ARMA MODELS APPLIED TO THE FLOW OF KARSTIC SPRINGS1

ABSTRACT: Autoregressive moving average (ABMA) models have been applied to study the flow series of the karstic springs of La Villa, Fuente Mayor (Spain), and Aliou (France). The theoretical meaning of the parameters involved in the model upon applying it to a simplified scheme of the emptying of a karstic aquifer is first analyzed. The types of transformations necessary to apply these models to the flow series that lack normality and have strong periodic components are also indicated, as are the advantages of this type of model and the physical significance of the parameters obtained, with respect to the standpoint of hydraulics, ranging from rather homogeneous aquifers (La Villa) to extremely karstic (Aliou), including aquifers with intermediate characteristics (Fuente Mayor).     

Thermal and mechanical properties of poly(lactic Acid) and poly(ethylene/butylene Succinate) blends

In this study, blends of poly (lactic acid) (PLA) with poly(ethylene/butylene succinate) (Bionolle) have been investigated for their thermal and mechanical properties as a function of the concentration of Bionolle. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and tensile tests were used to characterize the blends. From the results of the DMA and DSC, it was found that this blend system was not miscible within the compositions studied. DSC results showed that adding Bionolle aids in crystallization of PLA. It was observed that increasing the Bionolle concentration led to a slight increase in the strain-at-break of the blends but a decrease in the Young’s modulus and ultimate tensile strength. Biaxially oriented films showed an increase in tensile strength, modulus, and strain-at-break.     

Synthesis of poly(hydroxyalkanoate) from hydrolyzed linseed oil

Pseudomonas putida was grown on a mixture of long-chain fatty acids obtained by hydrolysis of linseed oil. A poly(3-hydroxyalkanoate) containing 51.2% of unsaturated monomers was obtained. A considerable percentage (13.6%) was constituted by C₁₄ and C₁₆ monomers containing three double-bonds in the side chains. The polymer showed a high tendency to crosslink when it was kept in presence of air. In the crosslinked polymer no polyunsaturated monomers could be detected.     

平衡调温调湿方式中变流量冷冻水系统设计

通过对变流量冷冻水系统的分析指出，在运用平衡调温调湿方式的空调系统中，应用变流量冷冻水系统可以较大地节约能源和投资；并提出了实现这种应用的方法。     

施工企业安全文化的核心——保护员工的安全与健康

分析了企业安全文化的发展和施工安全的特点，围绕企业目标、市场占有率、生产成本、企业形象、经济效益等内容，论述了保护员工安全与健康是施工企业安全文化的核心     

基于神经网络的重大危险源动态分级研究

利用自组织神经网络对重大危险源进行动态分级研究，介绍了神经网络的模式聚类即分级法的自组织学习过程和算法，克服了以往危险源分级方法的某些局限性。在计算机上进行的模拟计算表明：基于自组织神经网络的重大危险源动态分级方法是合理可行的     

中国可持续发展与国家安全文化战略的新对策

“可持续发展”战略的实质是社会、经济发展与资源、环境相协调的一种发展模式。值得注意，这一人类社会发展模式中跨世纪重大转变的策略，尚未引起安全与减灾科技界的普遍关注，不仅在安全减灾战略研究中很少涉及，严重的是它阻碍了安全减灾诸领域跨世纪及决策课题研究的深度，造成与国际接轨进程缓慢。为此，立足可持续发展思路，并以全新视角、系统地讨论适宜安全减灾文化战略的总体对策，可望能为中国二十一世纪安全保障及科技发展提供科学指南     

地层塌陷的灾害及其防治研究中的关键问题

针对矿山开采沉陷的研究现状和生产实践的需要，提出了地层塌陷防治研究中拟解决的关键问题：岩体的工程属性、地层塌陷的力源、塌陷特征、防治措施，及解决途径；同时还论述了本学科的发展前景。