Investor demand and spot commodity prices

The on-going debate over the influence of investor demand on spot commodity prices largely attempts to assess this influence by measuring the growth in investor demand in recent years. Given the serious data problems that plague such analyses, this article pursues another approach in the hope of providing useful insights into the impact of investor demand on spot commodity prices. It focuses on the mechanisms by which investor demand affects spot prices, and in particular on two questions. First, how does an increase in investor demand on the futures markets affect the spot market and spot price? Second, when investor demand is increasing and pushing a commodity's price up, do physical stocks of the commodity also have to be rising, as economists and others widely assume?On the first question, the article concludes that a surge in investor demand raising prices on the futures markets will have a direct and comparable effect on the spot market prices when these markets are in strong contango. However, when markets are in weak contango or backwardation, price movements in the futures markets have a much looser effect on spot prices. As a result, changes in investor demand on the futures markets may have little or no influence on spot prices in the absence of a strong contango. Instead, changes in fundamentals (that is, producer supply and consumer demand) and possibly changes in investor demand taking place directly on the spot market largely determine the spot price at such times.On the second question, the article shows that investor demand can be pushing up a commodity's price even when investor stocks are falling, despite the widespread presumption to the contrary.     

Patience is a virtue: Problems of regulatory governance in the Indonesian mining sector

Mining investment in Indonesia has been at a standstill for a decade. Clearly. international mining companies regard the country as a high risk destination for capital. Yet Indonesia is one of the most highly mineralised countries in the world and has expressed a desire to increase investment in the sector in the coming years. As a first step in this direction the government has introduced a new mineral and coal mining law to replace the highly regarded Contract of Work system. The government argues that this new law will reinvigorate mining investment in the country. This paper suggests that the new mining law will do little to improve the situation. Indeed, it is unlikely that Indonesia will become a preferred destination for mining investment in the foreseeable future. Poor regulatory architecture, endemic corruption, and a lack of institutional capacity continue to be of concern to investors.     

电-Fenton法预处理青霉素废水的降解规律研究

研究电-Fenton法预处理青霉素钠(penicillin G sodium,PGN)模拟废水的降解规律,分析预处理过程中PGN浓度、COD、TOC的变化情况及BOD5/COD改善情况.当T=20℃、pH=3时,投加0.5g/L FeSO4、0.2 mL/L H2O2,于0.3 A电流下降解浓度为100 mg/L的PGN废水,120 min后PGN去除97.9%,COD去除76.7%,TOC去除59.8%,BOD5/COD由0升至0.4,有效提高了废水的可生化性.以红外光谱(infrared spectrogram,IR)和液相色谱-质谱联用(Liquid chromatogramMass chromatogram,LC-MS)检测青霉素钠的降解产物,说明青霉素钠抑菌的关键结构b-内酰胺环被破坏,抗菌性消失,有助于生物处理有效去除.     

不同时间尺度下杭州市O3污染特征及控制因素

通过集中整治,我国空气质量已经有了明显改善,但在减排背景下近地面高ρ(O₃)仍是当前最复杂的大气环境问题之一.利用2011—2017年(尤其是杭州市G20峰会期间)ρ(O₃)、ρ(NO_x)、ρ(VOCs)和气象条件观测数据,分析了杭州市G20峰会期间及不同时间尺度下杭州市ρ(O₃)的变化特征及其影响因素.结果表明:①杭州市ρ(O₃)日变化呈单峰型特征,15:00左右ρ(O₃)达最大值(98.55 μg/m3);ρ(O₃)周变化存在“周末效应”,周末ρ(O₃)明显高于工作日;1 a中4—9月为ρ(O₃)高值期,ρ(O₃)峰值出现在5月和9月.以2013年为界,将2011—2017年ρ(O₃)变化分成下降和上升2个阶段,2011—2013年呈下降趋势,降幅约为15.02 μg/m3,2014—2017年呈上升趋势,增幅约为23.25 μg/m3.②减排措施的实施对ρ(O₃)存在双重作用,其可通过降低前体物质量浓度抑制O₃的生成,又能引起大气污染物质量浓度下降、太阳辐射增强,从而促进O₃的生成.当O₃前体物质量浓度较低时,在强太阳辐射等气象条件驱动下,近地面仍会呈现高ρ(O₃)的现象.③气象条件是驱动ρ(O₃)日、月变化的控制因素;相反,前体物质量浓度则是ρ(O₃)周、年变化的控制因素,此时VOCs或NO_x控制区、“周末效应”等ρ(O₃)变化特征开始显现.研究显示,不同时间尺度下杭州市O₃污染的控制因素不同.      

城镇燃气管道动火作业安全评价

针对城镇燃气管道动火作业的高危险性,为保障生命财产安全,提出一种基于未确知测度的安全评价方法。首先,从动火施工作业的前、中、后3个阶段对整个作业过程进行安全分析,并基于作业的前阶段建立安全评价体系。然后,引入未确知测度模型,将因素的量化值与测度函数结合得出测度评价矩阵,采用变异系数法处理评价矩阵,确定各危害因素的客观权重。最后,根据测度评价矩阵与因素权重得出动火作业的安全等级,并对危害因素进行排序。实例结果表明:应用该方法能有效地确定出城镇燃气管道动火作业的安全等级,对于不安全的施工作业,可根据排序确定高危险因素,并采取措施降低其危险性,提高整个动火作业过程的安全性。     

LFT-G注塑工艺在玻璃钢安全帽生产中的应用

玻璃钢安全帽因具有强度高、耐高温,耐水、酸、碱、油、化学腐蚀及良好的绝缘性等特点,被广泛应用于石油化工、矿山、电力、冶炼等多个行业。目前,玻璃钢安全帽的生产工艺仅有两种,一是手糊,二是模压。但这两种生产工艺不仅存在粉尘、噪声、有毒物质等多种职业危害因素,而且由于部分关键工序采用手工制作,因而造成玻璃钢安全帽的质量性能的不稳定。使用LFT-G（长纤维增强热塑性塑料颗粒）作为原材料,将注塑工艺引进玻璃钢安全帽的生产中,实现了玻璃钢安全帽的注塑生产。这种工艺,不仅职业危害因素大大减少,而且也因关键工序中不存在手工作业,从而大大增加了玻璃钢安全帽质量的稳定性,同时,由于LFT-G粒料的长度增加,经过加工后,安全帽成品中的纤维长度也会增加,使得安全帽的抗冲击性能等满足标准要求。为此,以LFT-G为基础的玻璃钢安全帽的注塑工艺具有广阔的应用前景。     

SPE-RRLC-MS/MS法测定制药废水中青霉素G

建立了利用固相萃取-高分离度快速液相色谱-串联质谱(SPE-RRLC-MS/MS)测定制药废水中青霉素G残留的方法。水样以30%硫酸锌+20%亚铁氰化钾作为沉淀剂沉淀蛋白质后,上清液采用Oasis HLB固相萃取柱富集和净化,以0.01 mol/L乙酸铵溶液(加0.1%甲酸)+乙腈作为流动相进行等度洗脱,经Agilent Plus C18柱分离后,在串联质谱ESI(+)源下进行MRM检测。该方法的青霉素G检出限(S/N=3)为0.02μg/L,目标物在0.0020～1.0 mg/L范围内线性关系良好,线性相关系数为0.9997。在0.20,1.0,2.0μg/L添加水平平均回收率为74.6%～101.4%,相对标准偏差为4.49%～8.17%。该方法灵敏度高、重现性好、定性定量准确,可满足制药废水中青霉素G残留检测的要求。     

Human-derived cell lines to study xenobiotic metabolism

In vitro systems make for rapid identification of xenobiotic effects and can be used to study cellular and subcellular toxicity mechanisms. In this report the metabolic competence of two human-derived cell lines, a hepatic (Hep G2) and a pulmonary one (A549) was tested. In the two cell systems the capability to activate Benzo[a]Pyrene through the cytochrome P450 enzyme system and to form reactive metabolites was analysed. ³H-BaP and the scintillation counting analysis were used to show the differences of the metabolic activity in Hep G2 and A549. A similar time course of ³H-BaP uptake was observed in the cell systems. Nevertheless, in the two cell lines the distribution of radioactive metabolites seemed to reflect a specific tissue response to toxicity.     

固相萃取-毛细管气相色谱法测定地表水中硝基苯类化合物

建立了固相萃取-毛细管气相色谱测定地表水中硝基苯类化合物的方法,优化了试验条件。方法线性良好,10种硝基苯类化合物的检出限为0．05μg／L～0．15μg／L,实际样品测定的RSD为1．7％～5．0％,平均加标回收率为80．8％～117％。     

基于TD-SCDMA网络的汽车防盗系统

汽车防盗系统对于汽车的安全很重要,但是传统的防盗系统在车受到袭击时在远处的车主无法观察到车的情况.使用CDMA网络的3G手机不仅能够传输音频信号,还可以传输视频信号.因此将3G手机运用于汽车防盗系统能提高其防盗能力.