Construction of an Optimal Sequential Plan for Testing a Treatment for an Adverse Effect

Abstract

Classical sequential procedures that collect a single observation at a time are often found impractical, expensive, and time consuming. Sequentially planned procedures, or simply sequential plans, extend and generalize the concepts of sequential analysis by allowing observations to be collected in groups of variable sizes. After every group, all of the previously collected data are used to determine the next course of action. An optimal (Bayes) sequential plan minimizes the (Bayes) risk function that combines the decision loss, observation (variable) cost, and group (fixed) cost. In general, determining the optimal sequential plan remains an open and challenging problem mainly because it requires risk optimization over a huge and rather unstructured set of all sequential plans. This article demonstrates how to obtain the optimal solution for a particular class of problems that may arise in testing a treatment for a rare but severe adverse effect. This solution is obtained by studying a number of properties of the Bayes sequential plan such as transitivity and monotonicity. This allows one to reduce the search to a small, manageable set of sequential plans within which the optimal plan can be calculated.     

Feed Cycling in Dead End Filtration

The dead end ultrafiltration of dispersions of active carbon in water was studied. High flux of the permeate and effective purification were goals of the studies. Cyclical flow of the feed (cycling) was found to be the best condition for good purification. During the purification of the membrane, an air/water dispersion was injected into the hollow fiber membrane (air sparging) to improve the cleaning effect. A Simplex optimization of significant parameters was carried out. The behavior of pressure drop and module entrance pressure permitted the classification of the values into two groups. A different build-up of the cake of these groups during the filtration is possible.     

浙江省海水淡化工程"十一五"水利规划

在对沿海和海岛地区实地调查、收集大量资料的基础上，分析研究了海水淡化技术的应用现状、适用性、吨水投资、制水成本以及对水源和运行管理等要求，对浙江省海水淡化工程进行了规划。规划近期规模为2．69万m^3／d，远期新增2．85万m^3／d，总建设规模5、54万m^3／d，规划工程近期建设投资21770万元，远期23100万元；规划确定的滩涂水资源水处理工程规模，近期为7000m^3／d，工程投资5600万元；远期为81000m^3／d，工程投资56700万元。文章还提出了开源节流、节能的建议措施。     

轮胎行业密炼用电削峰填谷研究

从国家出台峰谷电价制度以来,许多企业致力于削峰填谷的用电管理策略。本文首先从胶料标准和耗电差异两个方面,分析密烁工序进行削峰填谷的可行性,然后确定削峰填谷模型,重点详述了实现削峰填谷的计划调度算法,并进行实际数据的验证,最终达到预期目标。最后,介绍软控已经集成削峰填谷算法的计划调度产品。     

Analysis of the specimen shape and aging protocols in the adhesive strength between dentin and resin composite

The objective of this study was to evaluate the aging protocols and the specimen shape (sticks and dumbells) in the adhesive strength between dentin and resin composite during micro-tensile stress. The specimens were submitted to no aging protocol, mechanical cycling (using macro and micro-rotation methods), thermal cycling and micro-tensile test. The stress distribution for the two specimen shapes was performed by finite elements analysis. Data were submitted to 3-way ANOVA and Tukey Test (α = 0.05). There is no statistical difference considering the interactions among the factors: specimen shape, thermal cycling, and mechanical cycling. Also, the mechanical cycling, for both methods, micro or macro-rotation, and the thermal cycling did not affect the adhesive strength of the samples. However, the specimen with the dumbbell shape showed higher adhesive strength (16 ± 3 MPa) than the stick shape specimen (11 ± 2 MPa). The stress distribution in dumbbell shape was more homogeneous than in the sticks. It can be concluded that the aging protocols tested were not enough to degrade the adhesive interface and the dumbbell shape specimen is better to predict the real adhesive strength developed in the interface.     

Power-to-Fuels: E-Fuels as an Important Option for a Climate-Friendly Mobility of the Future

The Paris climate accord – in continuation of the original Kyoto agreement – and the German federal government's climate protection plan establish ambitious goals for overall CO₂ reduction. In 2050, a reduction of 80–95 % in comparison to the reference year 1990 is aspired for. This essay tries to outline challenges and boundary conditions for using e-fuels to directly substitute currently used fossil fuels in internal combustion engines and turbines.     

谈确保石化工程项目顺利实施的措施

石化工程往往投资规模大,而且特殊的生产条件和安全要求对工程质量提出了严格要求,对工程的管理亦提出了高要求。文章拟通过对石化工程项目策划的论述,阐述作为一名项目经理应如何组织策划以有效地保证项目的顺利实施,取得令人满意的工作效果。     

新形势下我国煤炭洗选加工现状及展望

分析了煤炭行业面临的新形势,指出"双碳"目标对煤炭行业影响巨大,煤炭行业需要做好煤炭向基础能源和保障能源作用转变过渡的准备;介绍了"十三五"以来我国煤炭洗选加工和煤炭质量情况,指出了"十四五"期间选煤发展面临的挑战,展望了2025年选煤发展的主要指标,提出加速推进煤炭洗选业发展的建议.     

Lithium cycling efficiency and conductivity for high dielectric solvent/low viscosity solvent mixed systems

Lithium cycling efficiency on a lithium substrate (Li-on-Li cycling) and conductivity for various mixed solvent systems of high dielectric solvent (HDS) and low viscosity solvent (LVS) were examined for secondary lithium batteries. For the HDS, sulfolane, dimethylsulfoxide, γ-lactones, propylene carbonate (PC) and ethylene carbonate (EC) were used. For the LVS, tetrahydrofuran (THF), 2-methyl-THF, 1,2-dialkoxyethanes and 1,3-dioxolane (DOL) were used. For the solute, LiAsF₆, LiBF₄, LiCF₃CO₃ and LiClO₄ were used. Lithium cycling efficiencies newly measured on a Li substrate (E_a) for EC/LVS or PC/LVS were ca 5% or 15% higher than those previously obtained by simple cycling of Li on a Pt substrate, while the order of Li cycling efficiencies to LVS change is similar in both cases, except for EC/DOL or PC/DOL. The reasons seem to be that the Li-on-Li cycling minimizes the influence of electrochemical Li/Pt alloying and partial solvent oxidation during the cycle on Li cycling efficiency. The E_a values in HDS/LVS mixed systems incorporating LiAsF₆ or LiClO₄ tended to increase with a decrease in the reactivity to Li, of not only LVS but also HDS. EC/THF systems incorporating LiAsF₆ or LiClO₄ showed high E_a values of ca 95% even by Li-on-Li cycling, the value being higher than those (ca 92%) for LiBF₄ or LiCF₃SO₃ systems. In addition, for all the HDS/LVS mixed systems examined in this work, conductivities were higher than those for HDS or LVS single solvent systems. In regard to both conductivity and Li cycling efficiency, HDS/LVS mixed systems are considered to be effective in various lithium battery applications.     

Procedural bases for standardizing water use in branch plants

Conclusions Standardization of water use in branch plants will make it possible to determine limits for water use, to plan measures for current and future periods, to put in order the allowance for water consumption and its control, to reduce the consumption of fresh water as compared with its actual consumption, and to ensure fulfillment of planned figures on water use.A procedure is described for calculating specific norms in water consumption in the manufacture of viscose fibre.Translated from Khimicheskie Volokna, No. 6, pp. 45–47, November–December, 1983.     

我国塑料管道行业"十一·五"期间发展概况和"十二·五"期间发展趋势浅析

综述了我国塑料管道行业在"十一·五"期间的发展状况,包括产量及出口情况;简单介绍了塑料管道的应用领域;指出了"十一·五"期间塑料管道行业存在的问题;最后,提出了"十二·五"期间我国塑料管道行业的发展目标,并对今后的发展给出了一些建议。     

A quantitative study of shape change in zinc secondary electrodes

Zinc electrode shape changes resulting from cell cycling have been studied. Experiments have been performed using zinc-silver oxide secondary cells of an industrial type. The results indicate that the extent of shape change is directly affected by the rate of discharge and charge, and the ZnO content of the electrolyte. The zinc electrode shape change can be mitigated by adding to the edge sections of the separator system a layer of non-woven fabric treated with Fe(OH)₂, The extent of shape change can also be reduced by increasing the separator thickness at the plate periphery. The orientation of the zinc electrode with respect to the earth's gravitational field (horizontally or vertically) on cycling, and the preparation methods for the zinc electrode (electrodeposition or slurry paste) have no apparent effect on the extent of zinc electrode shape change resulting from cell cycling.     

High-entropy thermal barrier coating of rare-earth zirconate: A case study on (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Zr2O7 prepared by atmospheric plasma spraying

We report a double-ceramic-layer (DCL) thermal barrier coating (TBC) with high-entropy rare-earth zirconate (HE-REZ) as the top layer and yttria stabilized zirconia (YSZ) as the inner layer sprayed on Ni-based superalloy by atmospheric plasma spraying. La₂Zr₂O₇ (LZ) was selected as a reference for the HE-REZ. Thermal cycling test results demonstrate that the HE-REZ/YSZ DCL coating exhibited obviously improved thermal stability when compared to the LZ/YSZ DCL coating. The reasons for the improvement of the thermal shock resistance are considered to be the anti-sinterability of the HE-REZ ceramics during the thermal cycling test attributed to the sluggish diffusion effect and as well as the better match in the coefficient of thermal expansion of HE-REZ coating with the YSZ inner layer. In addition, the HE-REZ coating maintains fluorite structure after thermal cycling test. This study makes one step forward in the development and application of high-entropy rare-earth zirconate ceramic thermal barrier coatings.     

课程地图规划建置之探讨

随著资讯科技的进步,网际网路的发展,已逐渐改变教师的教学与学生的学习方式,也使得线上课程地图的建置实行变得可行。且在高等教育系所评鉴项目中也将发展课程地图列为重要指标,可见课程地图发展的重要性。常见的课程地图主要以年级、类别、阶段、结合课程与职涯、学习领域或等级等几个类型来呈现;但不管以何种方式呈现,现有的课程地图大多以“学校本位”、“系科、教师本位”来发展。学生若以此课程地图学习,则容易陷于选课迷失当中;造成学习成就与实际就业需求将会有所落差,无法真正符合业界、就业的需要。但研究型与教学型大学的课程地图发展是无法一概而论的,若是以就业为导向之大学则不太适合以此方式来发展课程地图。 本研究建构一套符合“教学实用型”定位的大学课程地图模式,以“学生本位”、“业界所需”为出发点,制定学生毕业后未来就业应具备的专业核心能力,以规划系科相关课程,并以学生学习的成效（绩）、就业满意度调查分析等资讯回馈,作为适时调整修订课程规划、学生学习之参考依据。学生于大学修课期间,即能很简单、清楚地了解未来将从事的职涯进路、需取得的专业证照或继续升学研究所等所需修习之相关课程,并适时地加以检验、预测及修正,使学生得以”适性化学习”,真正培养业界所需核心能力之专业人才,达成“毕业即可就业,就业即可上手”的教育目标。     

大型碳酸钙矿山资源综合利用核心工艺研究

采用大型碳酸钙矿山资源综合利用核心工艺（包括：钙化工系列产品的“金字塔”规划、燃煤加工处理核心工艺和水循环梯级利用核心工艺）,能达到以下目标：所有工业废水实现循环利用,所有工业废渣实现有效利用,所有石灰窑气实现低成本、低碳净化处理。大型碳酸钙矿山资源综合利用核心工艺为未来大型碳酸钙矿山的资源综合利用和循环经济、低碳经济提供了一定的借鉴意义。     

Electric Field Cycling Induced Large Electrostrain in Aged (K0.5Na0.5)NbO3–Cu Lead‐Free Piezoelectric Ceramics

In this work, we studied aging and fatigue behaviors of 1.0 mol%Cu‐modified (Na_0.5K_0.5)NbO₃ lead‐free ceramics with double‐loop‐like characteristic, and found an interesting result of electric field cycling induced large electrostrain in the aged samples. After the “aging” treatment, the hysteresis loop “closes” totally and constricts completely at zero electric field, accompanying with a large nonlinear electrostrain of about 0.26%. More interestingly, the electrostrain in the aged sample is sensitive to the field cycling, which is pushed to a higher level of 0.47% approaching that of some Pb‐based antiferroelectric materials. A microscopic model of the domain switching‐related electrostrain effect is proposed to explain the field cycling induced large electrostrain in the aged samples. It can be identified due to the weakening of intrinsic restoring force for reversing the switched domains, induced by the point defects (defect dipoles) migration aligning along field direction during cycling, evident by the gradually “opened” hysteresis loop with cycling.     

Composition modulation of the fischer-tropsch synthesis over a supported cobalt catalyst

Different cycling strategies are explored to see if carbon chain growth can be enhanced and methane formation suppressed. Of the strategies considered, bang-bang cycling between H₂ and CO feeds substantially increased the consumption of CO and H₂, but the formation of higher hydrocarbons and olefins was reduced. The best strategy for longer chain hydrocarbons suitable for jet or diesel fuels was found to be cycling between syngas mixtures. None of the cycling strategies was able to produce C₈₊ or low-molar mass olefin yields that matched yields found in steady-state operation.     

Planung von Korrosionsschutzarbeiten bei Neubauten

Planning of Works Involving Prevention of Corrosion in New Buildings Like all other constructional procedures the works involving prevention of corrosion must also be carefully planned within the constructional programme. This is possible if during planning, the specialist for the prevention of corrosion obtains an insight of the plan along with all the individual objects. Consequently, the specialist determines the preventive measures like derusting, coating or metallizing for each of the objects. Choice of the systems for the prevention of corrosion is dependent on the amount of stresses which the object concerned has to endure later. In his orders and contracts the customer should exactly specify the services required.     

Electrochemical performance of spherical LiCoO2 with high stability in neutral aqueous electrolyte

Layer-structured lithium cobalt oxide (LCO) is one of promising electrode materials for secondary aqueous lithium-ion batteries, yet the effect of structural proton insertion in LCO in neutral aqueous electrolytes cannot be ignored. Present study investigates the electrochemical performance of polycrystalline spherical LCO in neutral aqueous saturated Li₂SO₄ solution. Herein, we for the first time demonstrate the dependence of LCO stability on the discharge cutoff potential. The applied LCO electrodes show good cycling stability within the potential window of 0.65–1.1 V vs. SCE, while electrochemical impedance spectrum (EIS) analysis detects no sign of proton intercalation. Moreover, the spherical LCO free from the proton intercalation exhibits a superior rate capability with 78% discharge capacity retention at 80 C. The lithium-ion chemical diffusion coefficient being seven times than that of irregular shaped LCO sample can be responsible for such significant rate capability. The cyclability testing depicts the better performance of spherical LCO in comparison with the counterpart, especially in terms of electrode activation time. Post cycling electrode characterization displays that the discharge capacity fading of LCO mainly results from the crystal grain deformation due to high potential cycling and can be alleviated by reducing the depth of charge.     

Cyclic chronopotentiometric studies of the LiAl anode in methyl acetate

The applicability of methyl acetate as a solvent for ambient temperature lithium secondary batteries was investigated using cyclic chronopotentiometry. Methyl acetate was found to be stable towards lithium-aluminium alloys and cycling up to more than 300 cycles was obtained with about 90% cycling efficiency. Water and other organic impurities have been identified in methyl acetate and a thorough purification procedure has been used to reduce these to acceptable levels. LiAsF₆, LiPF₆, LiClO₄ and LiBF₄ were investigated for use as supporting electrolytes and LiAsF₆ was found to be the best in terms of cycling efficiency, longer cycling numbers and yielding the lowest corrosion capacity loss rate. The development of the LiAl anode upon cycling was observed in parallel with the reduction in nucleation polarization potential, the increase in cycling efficiency, the lowering of concentration polarization at the electrode surface and the more ready acceptance of lithium deposition at the developed electrode. The optimum conditions for the development of the LiAl anode were found to exist at a current density of 5 mA cm^–2 and a charge density of 0.5 C cm^–2.