Accurately computing the optical pathlength difference for a michelson interferometer with minimal knowledge of the source spectrum

Astrometric measurements using stellar interferometry rely on precise measurement of the central white light fringe to accurately obtain the optical pathlength difference of incoming starlight to the two arms of the interferometer. One standard approach to stellar interferometry uses a channeled spectrum to determine phases at a number of different wavelengths that are then converted to the pathlength delay. When throughput is low these channels are broadened to improve the signal-to-noise ratio. Ultimately the ability to use monochromatic models and algorithms in each of the channels to extract phase becomes problematic and knowledge of the spectrum must be incorporated to achieve the accuracies required of the astrometric measurements. To accomplish this an optimization problem is posed to estimate simultaneously the pathlength delay and spectrum of the source. Moreover, the nature of the parameterization of the spectrum that is introduced circumvents the need to solve directly for these parameters so that the optimization problem reduces to a scalar problem in just the pathlength delay variable. A number of examples are given to show the robustness of the approach.     

The development of ‘green’ airports: Which factors influence willingness to pay for sustainability and intention to act? A structural and mediation model analysis

The study's purpose was to determine which factors influence a consumer's willingness to pay for sustainability and their intention to take action against climate change related to airports. An expanding body of literature relates to assessing whether consumers would be willing to pay for these ‘green’ practices in the aviation industry, such as biofuels or sustainable airport construction/renovations. While previous studies have experimentally examined these scenarios, we are aware of no prior research that has proposed and assessed a structural model related to determining which factors influence consumer's perspectives on ‘green’ airports. A sample of 722 eligible participants from the United States completed the study using Amazon's Mechanical Turk. We examined future time perspective, affect toward climate change, the perceived value of sustainability, and perceptions of climate change on the endogenous variables of willingness to pay for sustainability and intentions to take action against climate change. Six of the seven hypotheses proposed were supported. Affect, perceived value, and perceptions of climate change were all significant and positively related to willingness to pay, which was positively associated with intention to act. Two non-hypothesized paths, between perceived value and future time perspective, were also positively related to intention to act. The model explained 42% of the variance in willingness to pay and 66% in intention to act. These findings offer insights into what factors significantly influence these relationships as they relate to airports. Perceived value and perceptions of climate change had the largest effect sizes in the model and were significantly related to willingness to pay and intentions to act.     

外包钢加固火灾后钢筋混凝土柱的试验研究

通过3根外包角钢加固的ISO834标准火灾作用后钢筋混凝土柱的受力性能试验以及3根未加固的ISO834标准火灾作用后钢筋混凝土柱和3 根常温下钢筋混凝土柱的对比试验,研究了火灾后钢筋混凝土柱的性能以及外包钢加固火灾后钢筋混凝土柱的有效性。试验结果表明:火灾后试件的刚度退化显著,在该文的试验参数和升温条件下,从开始加载到80%极限荷载的不同加载阶段,轴压柱的轴向刚度只有常温下轴向刚度的0.22~0.37,偏压柱的弯曲刚度只有常温下弯曲刚度的0.13~0.18;外包角钢加固对火灾后试件的刚度修复有一定的效果,不同荷载水平下,加固后轴压试件的轴向刚度与常温下试件刚度的比值在0.41~0.89 之间,偏压试件的弯曲刚度与常温下试件刚度的比值在0.33~0.91 之间。火灾后试件承载能力退化严重,在该文的试验参数和升温条件下,火灾后试件的承载力水平只有常温下的0.25~0.37;利用外包角钢对火灾后的试件进行加固,能将试件的承载力提高至试件未受火时大致相当的水平,加固后试件的承载力与未受火试件承载力的比值在0.97~1.06 之间,外包钢加固对火灾后试件承载能力的修复效果十分显著。     

Monte Carlo simulation of creep failure in a 0°/90° plain weave SiC/SiC composite lamina

A Monte Carlo model of the effects of fiber creep in a 0°/90° plain weave ceramic-grade Nicalon reinforced SiC composite has been developed. Creep degradation of fibers was predicted to result in stress dependent premature failure of woven ceramic matrix composites, and that premature failure was modeled using a power-law. A power-law exponent of 3.1 ± 0.1 was predicted. The power-law exponent was predicted to be independent of initial crack size for crack length to specimen width ratios of 0.02, 0.10, 0.25, and 0.50. The power-law exponent was also predicted to be independent of the matrix to fiber strength ratio for ratios from 0.25 to 1.0. Premature failure in the 90° (transverse) tows resulted in premature failure of the composite for low values of the matrix to fiber strength ratio (less than 0.75), and decreased creep life was predicted for decreased matrix to fiber strength ratio. For a matrix to fiber strength ratio of 1.0, the creep life of the woven composite was predicted to be equivalent to a unidirectional composite. At small initial crack lengths, a 10% improvement in the creep life was predicted for a reduction in the matrix to fiber strength ratio from 1.0 to 0.75. This improvement was related to the formation of microcracks in the 90° tows and shielding of the macrocrack tip from accelerated creep damage. This improvement in the predicted creep life at a matrix to fiber strength ratio of 0.75 was predicted to be independent of applied stress. However, improvement of the creep life was not predicted to occur for larger values of initial crack length.     

Synthesis of nanowires,nanorods and nanoparticles of ZnO through modulating the ratio of water to methanol by using a mild and simple solution method

ZnO nanowires, nanorods and nanoparticles through modulating the ratio of water to methanol have been synthesized by using a mild and simple solution method. The as-prepared ZnO nanostructures have been characterized by atomic force microscopy and X-ray photoelectron spectroscopy. With the increase of the ratio of water to methanol, the morphology of ZnO nanostructures varied form denser nanowires, to sparse nanowires, to nanorods, and then to nanoparticles. The ratio of water to methanol is supposed to play an important role in the formation of ZnO nanostructures. The mechanism of formation is related to the chemical potential, which is simply proportional to their surface ratio.     

Methodology of using delay-time analysis for a manufacturing industry

This paper has been written to give a methodology of applying delay-time analysis to a maintenance and inspection department. The aim is to reduce downtime of plant items and/or reducing maintenance and inspection costs, taking into account the possible environmental impact of a failure in terms of cost, both to the company and the environment. The paper also attempts to give a subjective measure of the consequences of such a failure in terms of cost to the environment, in monetary value to the company and the damaging effect to the company image.     

Electrophoresis-assisted active immunoassay

An active assay can be defined as that in which diffusion-controlled reactions are replaced by active delivery of analytes to probe molecules. The present paper describes an electrophoresis-assisted version of an active ELISA performed in tubes or wells with a dialysis membrane attached to their bottoms. The permeability of such a membrane to small ions allows us to apply electric field perpendicular to the membrane surface and to rapidly transport and concentrate charged macromolecular analytes in its vicinity. Probe molecules were either adsorbed or covalently linked to a modified surface of a membrane from regenerated cellulose. An active assay was performed both in separate cells and in 96-well microplates. It was demonstrated that the active assay format allows one (i) to reduce assay time to minutes instead of hours, (ii) to increase sensitivity by a factor of 10-300, and (iii) to capture within 10 min up to 70% of all the analyte molecules present in 0.36 mL of solution.     

基于茶马古道文旅发展下的羌族羊皮鼓创新设计

目的 研究茶马古道文旅融合下的羌族羊皮鼓发展现状,给处于发展滞后的羌族羊皮鼓创新设计提供方法与思路,实现羌族地区特色手工艺的传承发展与创新性转化。方法 根据茶马古道文旅发展下的文化产品需求,分析当下羌族羊皮鼓发展的困境与突破方向,探索羌族羊皮鼓创新发展应进一步加强文旅融合,丰富产品类型;加强特色发掘,增强文化创意;加强材料与工艺开发,增强材质与技术创新;加强科技融合,增强数字化产品创新等来实现羌族羊皮鼓的创新设计。结论 对处于茶马古道文旅发展下的羌族羊皮鼓传承与创新设计,需根植羌族特色文化,以现代化的设计手法,多元化的文化创意思维认识和新材料、新技术革新的手段来探索羊皮鼓的产品特征、审美意识、文化内涵与艺术形态,才能满足人们日益增长的文化生活需求,激发人们的购买欲望,带动产品的销售,推动羊皮鼓在现代生活中的活态发展,促进羌族传统文化在当下的文化价值、旅游价值和经济价值的实现。     

Intelligent machines in the twenty-first century: foundations of inference and inquiry

The last century saw the application of Boolean algebra to the construction of computing machines, which work by applying logical transformations to information contained in their memory. The development of information theory and the generalization of Boolean algebra to Bayesian inference have enabled these computing machines, in the last quarter of the twentieth century, to be endowed with the ability to learn by making inferences from data. This revolution is just beginning as new computational techniques continue to make difficult problems more accessible. Recent advances in our understanding of the foundations of probability theory have revealed implications for areas other than logic. Of relevance to intelligent machines, we recently identified the algebra of questions as the free distributive algebra, which will now allow us to work with questions in a way analogous to that which Boolean algebra enables us to work with logical statements. In this paper, we examine the foundations of inference and inquiry. We begin with a history of inferential reasoning, highlighting key concepts that have led to the automation of inference in modern machine-learning systems. We then discuss the foundations of inference in more detail using a modern viewpoint that relies on the mathematics of partially ordered sets and the scaffolding of lattice theory. This new viewpoint allows us to develop the logic of inquiry and introduce a measure describing the relevance of a proposed question to an unresolved issue. Last, we will demonstrate the automation of inference, and discuss how this new logic of inquiry will enable intelligent machines to ask questions. Automation of both inference and inquiry promises to allow robots to perform science in the far reaches of our solar system and in other star systems by enabling them not only to make inferences from data, but also to decide which question to ask, which experiment to perform, or which measurement to take given what they have learned and what they are designed to understand.     

Efficient structural computations with parameters uncertainty for composite applications

The aim of this paper is to propose a methodology in order to take into account the influence of uncertain data in structural calculations. To attain this goal, an approximation of the responses as a function of the uncertain data response called surface method (RSM) is proposed. In order to decrease the number of identification points necessary for the RSM, a progressive strategy is proposed. Error indicators are also used in order to increase the confidence. This strategy is applied to a laminate plate subjected to bending tests. The results are compared to Monte-Carlo simulations (considered as a reference). The method proposed in the present work permits to estimate correctly the whole response and is very simple to use (pre- and post-processing). This method is applied to asses the robustness of the point-stress method used to predict the rupture of perforated plates.     

Progress in the United States on Electromagnetic Standards and Measurements at 30 kHz to 1 GHz, 1963 through 1965

A digest of highlights is presented on the most significant U. S. contributions to the measurement of attenuation, impedance, phase, field strength, thermal noise, current, and voltage at 30 kHz to 1 GHz. A total of approximately 30 contributions are digested. The following accomplishments are among them: a supersensitive detector for a complex-insertion-ratio measurement system having accuracies of about 0.0005 dB/10 dB at 30 MHz; exact equations for mutual and self-inductance of various combinations of filaments, tapes, and bars; a modified Twin-T-Bridge for measuring resistances of 100 to 10 000 ohms to 15 MHz; a set of Q-factor standards for frequencies to 45 MHz based on data and experience accumulated over five years; a unique adjustable characteristic-impedance coaxial line; measurement of Q's greater than 100 000 of cryogenic circuits at frequencies to 300 MHz; a novel Tee-junction to enable calibrations of voltmeters of any practicable input impedances with VSWR's ranging from 1 to 200, to 1 GHz and higher; a miniaturized dipole-antenna field strength meter, employing a semiconducting plastic transmission line, to measure complex nearzone fields of 0.1 to 1000 volts per meter, from 150 kHz to 30 MHz; and a prototype 3-MHz model of precision thermal noise-power comparators for an equivalent noise-temperature range of 75 to 30 000°K at accuracies of 0.2 to 1 percent.     

Control of mechanical deformation of a laminate by electrical load to piezoelectric actuator considering the effects of damping and transverse shear

In this paper, we treat the control of dynamic deformation of a laminate by applying electrical load to piezoelectric actuators. Dynamic behavior of the laminate is analyzed considering the effect of damping due to interlaminar shear and the effect of transverse shear. The analytical model is a rectangular laminate composed of fiber-reinforced laminae and piezoelectric layers. The model is assumed to be a symmetric cross-ply laminate with all edges simply supported and to be subjected to unavoidable mechanical load and to electrical loads to piezoelectric actuators. Behavior of the laminate is analyzed based on the first-order shear deformation theory. The effect of damping due to interlaminar shear is incorporated into our analysis by introducing the interlaminar shear stresses which satisfy the Newton’s law of viscosity. The following quantities are obtained: (1) natural frequencies of the laminate, (2) weight functions for the deflection and rotations and (3) transient deflection due to loads varying arbitrarily with time. Moreover, the methods to control the deflection due to mechanical load by applying electrical voltage to the piezoelectric actuator are shown.     

Damage evolution in sinter-hardening powder-metallurgy steels during tensile and fatigue loading

The damage approach was used to compare the tensile and push-pull fatigue behaviour of two high-strength sinter-hardened powder metallurgy (PM) steels, with a density of 6.7 and 7.2 g/cm³. In both alloys, tensile damage was found to start when the ratio of the applied stress to UTS was greater than about 0.3. The tensile damage was due to localized yielding and, in a later stage, to the formation of several micro-cracks that joined to form more than one macrocrack. Fatigue damage was followed in the finite fatigue life regime and was found to develop through three stages. During the first one, damage increased with fatigue cycling up to the attainment of a plateau (second stage) that lasted to a fraction of about 0.9 of the fatigue life. The damage recorded during the second stage was very similar to that encountered in the tensile tests at the same stress to UTS ratio. The formation of microcracks was observed in the third stage only, when the fraction of fatigue life was greater than 0.9. During this stage damage increased very sharply and this was due to the growing and joining of the microcracks to form one long crack able to lead to final fracture.     

Development of an interactive simulation system for the determination of the pressure–time relationship during the filling in a low pressure casting process

An interactive computer simulation system has been developed in this study to aid the determination of the pressure–time relationship during the filling of a low pressure casting to eliminate filling-related defects while maintaining its productivity. The pressure required to fill a casting in a low pressure casting process can be separated into two stages. The first stage is to exert pressure to force the molten metal to rise in the riser tube up to the gate of the casting die, which varies from casting to casting due to the drop of the level of the molten metal in the furnace, whilst the second stage is to add an additional pressure to push the molten metal into the die cavity in a way that will not cause much turbulence and have the proper filling pattern to avoid the entrapment of gas while maintaining productivity.One of the major efforts in this study is to modify the filling simulation system with the capability to directly predict the occurrence of gas porosity developed earlier to interactively determine the proper gate velocity for each and every part of the casting. The pressure required to fill the die cavity can then be obtained from the simulations.The operation principles and the interactive analysis system developed are then tested on an automotive wheel made by the low pressure casting process to demonstrate how the system can aid in determining the proper pressure–time relations, the p–t curve, required to produce a sound casting without sacrificing productivity.     

Simultaneous design of a product family and its related supply chain using a Tabu Search algorithm

Product family design is currently facing a multitude of challenges, the main problem stemming from the diversity offered to consumers. To design a product family, designers have to define an efficient bill of materials which ensures product assembly within a predefined length of time in order to satisfy the synchronised delivery principle. In addition, the modules used to assemble the finished products have to be competitive in terms of logistical costs. The ability to anticipate the constraints associated with the production process and with transportation is consequently of great interest. In this paper, we focus on the process of identifying a set of modules to be used in the assembly of the finished product. The objective is to define the bill of materials for each product from the modules belonging to that set, and to assign these modules to distant facilities where they will be manufactured and then shipped to a nearby facility for final assembly within a specific time. We use a set partitioning formulations to represent the problem, and solve it by adapting a Tabu Search algorithm in which the assembly process and the supply chain design are considered at the same time.     

Removal characteristics of anionic metals by micellar-enhanced ultrafiltration

Surfactant-based separation of Fe(CN)(6)(3-) and CrO(4)(2-) using regenerated cellulose membrane was studied in order to assess the potential of micellar-enhanced ultrafiltration for the remediation of wastewater or groundwater polluted with ferriccyanide and chromate. In the ferriccyanide/octadecylamine acetate (ODA) and chromate/ODA systems, removal of ferriccyanide increased from 73 to 92% and to 98%, and that of chromate from 64 to 97% and to >99.9% as the molar ratio of ODA to ferriccyanide and to chromate increased from 1 to 2 and to 3, respectively. In the ferriccyanide/chromate/ODA system, while the removal of ferriccyanide increased from 62 to 72% and to 93%, the removal of chromate from 20 to 38% and to 68% as the molar ratio of ferriccyanide:chromate:ODA increased from 1:1:1 to 1:1:2 and to 1:1:4, respectively. With the molar ratio of 1:1:6, the removal was >99.9 and 98% for chromate and ferriccyanide, respectively. Ferriccyanide ions were more easily bound to ODA micelles because the binding power of ferriccyanide was greater than that of chromate.     

案例知识的产品造型设计方法研究

目的为设计出符合消费者感性需求的产品,适应大规模定制的生产模式,缩短产品开发周期并方便企业后期的产品迭代,提出了一种应用已有产品案例进行产品快速设计的方法。方法以对象设计知识分类理论为基础,融入了消费者感性意象这一特征,建立了案例造型知识库模型,并由此模型指导案例各特征知识的获取,由此建立案例造型知识库。结论依据设计需求,应用案例造型知识库进行案例的检索、匹配、推理、变异,完成对四阀饮料机的方案设计,验证方法的可行性与高效性。     

3D Printing of Textiles: Potential Roadmap to Printing with Fibers

3D printing (3DP) has transformed engineering, manufacturing, and the use of advanced materials due to its ability to produce objects from a variety of materials, ranging from soft polymers to rigid ceramics. 3DP offers the advantage of being able to print at a variety of lengths scales; from a few micrometers to many meters. 3DP has the unique ability to produce customized small lots, efficiently. Yet, one crucial industry that has not been able to adequately explore its potential is textile manufacturing. The research in 3DP of textiles has lagged behind other areas primarily due to the difficulty in obtaining some of the unique characteristics of strength, flexibility, etc., of textiles, utilizing a fundamentally different manufacturing technology. Textiles are their own class of materials due to the specific structural developments that occur during the various stages of textile manufacturing: from fiber extrusion to assembly of the fibers to fabrics. Here, the current 3DP technologies are reviewed with emphasis on soft and anisotropic structures, as well as the efforts toward 3DP of textiles. Finally, a potential pathway to 3DP of textiles, dubbed as printing with fibers to create textile structures is proposed for further exploration.