Chemometrics in fuel science: demonstration of the feasibility of chemometrics analyses applied to physicochemical parameters to screen solvent tracers in Brazilian commercial gasoline

Samples of commercial gasoline, from the National Program of Fuel Quality Monitoring of the National Petroleum Agency, were collected from gas stations located in the Midwestern state of Sao Paulo, Brazil, and analyzed by several physicochemical standard methods established by ANP Resolution no. 309. Also, important information related to tampering was analyzed with the marker solvent. Statistical analysis and exploratory chemometric were employed to discriminate the presence of markers of solvents in commercial gasoline. The results showed that statistical and chemometric parameters such as atmospheric distillation temperatures T10 and T90, RON, benzene and saturated and aromatic hydrocarbons satisfactorily describe the presence of marker solvent, usually with a probability exceeding 70%. Furthermore, after optimizing the SIMCA algorithm, sensitivity in the training set with cross‐validation leave‐one‐out (83.8%) and the set of prediction (77.1%) were revealed. The proposed method will become indispensable and recommended for discriminating samples of fuels for commercial applications in routine monitoring programs and quality control. Copyright © 2011 John Wiley & Sons, Ltd.     

不忽略一次项损失时望大特性质量损失函数设计

田口先生提出的质量特性损失函数是用二次项来表示的,对于望大特性而言,质量特性实际上不可能达到无穷大。讨论了不能忽略一次项损失时,望大特性质量损失函数应采用二次式表示。研究了二次式损失函数中一次项损失系数和二次项损失系数确定的方法。比较分析了二次式损失函数中一次项损失和二次项损失的大小。本文的研究结果显示,田口先生经典的二次项损失函数是二次式损失函数的一种形式。实际问题也验证了本文的研究成果。     

在风险规避下考虑质量因素的竞争供应链的均衡策略研究

在供应链竞争环境下,针对具有风险规避特征的供应商和零售商组成的供应链,采用博弈及优化理论探讨竞争环境下风险规避参与者的均衡定价及质量水平,并分析风险规避度对参与者均衡定价和质量水平的影响.借助数值分析,研究了系统中各参数对决策的影响.数值仿真结果表明,各风险规避参与者的定价随着自身风险规避度的增大而减小,即参与者越害怕风险其所制定的价格越低.另外,市场竞争的存在在某种程度上会削弱风险规避特征对参与者决策的影响,使参与者的定价提高,增加参与者的收益.     

Development of a Water Matrix Certified Reference Material for Volatile Organic Compounds Analysis in Water

Water matrix certified reference material (MCRM) of volatile organic compounds (VOCs) is used to provide quality assurance and quality control (QA/QC) during the analysis of VOCs in water. In this research, a water MCRM of 28 VOCs was developed using a “reconstitution” approach by adding VOCs spiking, methanol solution into pure water immediately prior to analysis. The VOCs spiking solution was prepared gravimetrically by dividing 28 VOCs into seven groups, then based on ISO Guide 35, using gas chromatography-mass spectrometry (GC-MS) to investigate the homogeneity and long-term stability. The studies of homogeneity and long-term stability indicated that the batch of VOCs spiking solution was homogeneous and stable at room temperature for at least 15 months. Moreover, the water MCRM of 28 VOCs was certified by a network of nine competent laboratories, and the certified values and expanded uncertainties of 28 VOCs ranged from 6.2 to 17 μg/L and 0.5 to 5.3 μg/L, respectively.     

An instantaneous replenishment model under the effect of a sampling policy for defective items

We propose to study a EOQ-type inventory model with unreliable supply, with each order containing a random proportion of defective items. Every time an order is received, an acceptance sampling plan is applied to the lot, according to which only a sample is inspected instead of the whole lot. If the sample conforms to the standards, i.e. if the number of imperfect items is below an “acceptance number”, no further screening is performed. Otherwise, the lot is subject to 100% screening. We formulate an integer non-linear mathematical program that integrates inventory and quality decisions into a unified profit model, to jointly determine the optimal lot size and optimal sampling plan, characterized by a sample size, and an acceptance number. The optimal decisions are determined in a way to achieve a certain average outgoing quality limit (AOQL), which is the highest proportion of defective items in the outgoing material sold to customers. We provide a counter-example demonstrating that the expected profit function, objective of the mathematical program, is not jointly concave in the lot and sample size. However, we show that for a given sampling plan, the expected profit function is concave in the lot size. A solution procedure is presented to compute the optimal solution. Numerical analysis is provided to gain managerial insights by analyzing the impact of changing various model parameters on the optimal solution. We also show numerically that the optimal profit determined using this model is significantly higher when compared to the optimal profit obtained using Salameh and Jaber (2000)’s [1] model, indicating much higher profits when acceptance sampling is used.     

Photoinjector beam quality improvement by shaping the wavefront of a drive laser with oblique incidence

To increase the quantum efficiency (QE) of a copper photocathode and reduce the thermal emittance of an electron beam, a drive laser with oblique incidence was adopted in a BNL type photocathode rf gun. The disadvantageous effects on the beam quality caused by oblique incidence were analyzed qualitatively. A simple way to solve the problems through wavefront shaping was introduced and the beam quality was improved.     

机载光学平台平均流场气动光学效应研究

使用选区电子衍射软件模拟机载光学平台绕流流场,根据绕流流场定量研究了气动光学平均流场效应的性质及其随激光传输角度的变化。发现平均流场气动光学效应引起的波前畸变主要是低阶像差,整体倾斜占比约92%,整体倾斜、离焦和像散三项总和占比平均值99%以上;随传输方向变化,波前像差均方根值以及波前性质有显著不同:对于不同的传输方向,光程差(OPD)均方根值(RMS)的变化范围从0.13～1.20μm,光轴偏向角的变化范围从1～12μrad。去倾斜后的波前像差引起的光束质量因子β值,对所有方向的统计平均值为1.8;校正了离焦和像散后,光束质量因子β值的平均值为1.16。光束质量因子β值随口径增加而增加,无自适应光学校正时变化规律接近线性。     

光学系统辅助装调技术研究

光学系统装调技术是高功率激光工程中的关键支撑技术之一。对光学系统装调中影响系统光束质量的误差来源进行了分析,并根据像差的装调方式进行了分类。对这两类像差的辅助装调方式进行了比较和仿真模拟。针对第一类像差,在装调模型中代入失调系统检测得到干涉图,利用计算机辅助装调模型计算出失调量的大小和方向,确定出系统的装调方案。仿真结果显示,对系统调整工作有较好指导作用。针对第二类像差,利用元件加工面形之间波像差的互补性,优化调整光学元件的装校姿态。仿真结果显示,系统的光束质量口由预期的4．916优化为1．187,提高了多元件光学系统的光束质量。     

用于水果品质检测的小型成像光谱仪

利用成像光谱可同时获得水果的成像信息和光谱信息,实现水果外部和内部品质的高精度、无损伤、无污染的大面积瞬态检测。为了获得水果的成像光谱,设计了一种以自主研发的凸面光栅作为核心元件的小型成像光谱仪,它具有成像质量好、体积小、重量轻等优点,光谱分辨率在578nm波长处达2.1nm,光谱谱线弯曲和色畸变均小于0.6%。对该小型成像光谱仪进行了检测和苹果成像光谱测量实验,结果表明:该成像光谱仪满足设计要求且可以快速的获得苹果的高精度成像光谱,从而进行水果的品质检测。     

基于光谱分析的紫外水质检测技术

提供了一种基于紫外可见光谱的水质检测系统,各水样吸光度与COD线性拟合R2均大于0.99,单次测量在1s内。同时提出了光谱直接对比和归一化分析方法以及对应的指标参数。通过对大量的邻苯二甲酸氢钾标准溶液和实际水样的实验验证,采用这些光谱分析方法可将水样进行归类,从数据库中寻找适合待测水体的数学模型,进而提高紫外水质检测技术的泛化能力,同时还能得到其他水质指数。