New improvement opportunities through applying topology optimization combined with 3D printing to the construction of gearbox housings

Forschung im Ingenieurwesen - The construction of gearbox housings is severely restricted by all the currently used machining processes. 3D metal printing opens up new possibilities in...     

基于EMD-EDT的行星齿轮箱特征提取及状态识别方法研究

针对行星齿轮箱特征提取及状态识别中存在的难点问题,本文首先总结适用于行星齿轮箱状态识别的36个特征参数并详细说明各参数的来源及提取方法,提出基于EDT的两阶段特征参数选择及加权方法,得到新的组合特征参数。提出基于EMD-EDT的行星齿轮箱状态识别方法;首先提出基于能量比的包含敏感故障信息的固有模态函数（IMF）选择方法,然后选择提取筛选出的各IMF的组合特征参数构成特征矩阵作为EDT的计算输入,最后智能的输出评估结果。利用行星齿轮箱预置故障实验数据验证所提出方法的可行性和有效性及EMD分解、特征选择和加权过程的必要性。     

Methods for improving the quality of spectral analysis of stationary operational vibrations

Translated from Izmeritel'naya Tekhnika, No. 4, pp. 35–38, April, 1993.     

A framework for improving the efficiency of operational testing through Bayesian adaptive design

When developing a product, it is important to consider product performance from a user perspective. This type of evaluation can be done through operational testing—assessing the ability of representative users to satisfactorily accomplish tasks with the product in operationally representative environments. This process can be expensive and time-consuming, but is critical to understanding whether the product can adequately do the job for which it was designed. We show how an existing design of experiments (DOEs) process for operational testing can be leveraged to construct a Bayesian adaptive design. This design, nested within the larger design created by the DOE process, allows interim analyses to stop testing early for success or futility. Representative simulations are presented to demonstrate how these interim analyses can be used in an operational test setting, and reductions in necessary test events are shown. The application of Bayesian-adaptive design methods will allow future operational testing to be conducted in less time and at less expense, on average, without compromising the ability of the existing process to verify the product meets the user's needs.     

AMGA2: improving the performance of the archive-based micro-genetic algorithm for multi-objective optimization

In this article, an improved Archive-based Micro Genetic Algorithm (referred to as AMGA2) for constrained multi-objective optimization is proposed. AMGA2 is designed to obtain fast and reliable convergence on a wide variety of optimization problems. AMGA2 benefits from the existing literature in that it borrows and improves upon several concepts from existing multi-objective optimization algorithms. Improvements and modifications to the existing diversity assessment techniques and genetic variation operators are also proposed. AMGA2 employs a new kind of selection strategy that attempts to reduce the probability of exploring less desirable search regions. The proposed AMGA2 is a steady-state genetic algorithm that maintains an external archive of best and diverse solutions and a very small working population. AMGA2 has been designed to facilitate the decoupling of the working population, the external archive, and the number of solutions desired as the outcome of the optimization process. Comprehensive benchmarking and comparison of AMGA2 with the current state-of-the-art multi-objective optimization algorithms demonstrate its improved search capability.     

立磨减速机斜齿轮副啮合性能分析及齿形优化

齿轮运转过程中,偏载会影响齿面啮合性能,降低齿轮的寿命,因此,需要减小偏载带来的不利影响.利用Romax软件的微观几何设计功能,以传动误差的波动值最小为目标函数,以齿廓的修缘量和起始角、齿向的偏斜和鼓形量为设计变量,对立磨减速机平行级斜齿轮副的修形参数进行优化,以寻找最佳修形量.对比发现,修形后齿轮副的传动误差、单位长度的法向载荷、最大接触应力以及轮齿所受载荷均有较大改善,优化效果较为明显.齿轮微观几何设计可有效解决偏载,改善轮齿的啮合性能,提高传动的平稳性.     

Principles of resource-effectiveness and regulatory-effectiveness for risk-informed applications:: Reducing burdens by improving effectiveness

Principles of resource-effectiveness and regulatory-effectiveness are presented which systematically compare the resources expended on a requirement or activity versus its risk importance. To evaluate resource-effectiveness and regulatory-effectiveness, cost-benefit analysis principles are generalized to resource versus risk importance principles. It is shown that by applying resource-importance analyses, current requirements and activities can be systematically evaluated for their resource-effectiveness and their risk-consistency. Strategies can then be developed to maximize both resource-effectiveness and risk-consistency which reduces unnecessary burdens while maintaining risk or reducing risk. The principles, approaches, and implementation schemes which are presented provide a systematic process for evaluating and optimizing resource-effectiveness and regulatory-effectiveness. The illustrations that are presented show that current NRC and industry actions are not resource-effective. By improving their resource-effectiveness and risk-consistency, significant burden reductions are achievable while risk, e.g. core damage frequency, is maintained or is reduced. The illustrations show that by optimizing industry resources and NRC resources with regard to their risk-effectiveness, significant burden reductions are achievable for both the industry and NRC. Algorithms and software exist for broad-scale implementations. Because of the burden reductions which are identified and the improvements in risk-consistency which result, resource-importance analysis should be the first step in risk-informed applications. Resource-importance analysis is so important and can provide such large benefits that it needs to be carried out on all current requirements that are addressed by risk-informed applications.     

Bending behavior of empty and foam-filled beams: Structural optimization

Bending crash tests on empty and foam-filled square aluminum beams have been performed. Furthermore, in order to find more details about crash processes, finite element simulations have been done. In terms of improving crash behavior of the aluminum beams, the crashworthiness optimization procedure has been applied to maximize specific energy absorption of the square beams with the target energy absorption. A comprehensive study about the strengthening effect of foam in the filled beam has been performed and finally the optimization technique has been implemented to find the optimum foam-filled beam that absorbs the same energy as optimum empty tubes with lower weight.     

Reducing barriers of communication across Indian languages: Anai andes approach to mass media

The present paper identifies some nonlinguistic and linguistic barriers that will have to be overcome by any system for automatic and simultaneous communication of news, commercial advertisements, and other items of information and entertainment by mass media across some Indian languages. The paper also presents a brief account of some theories for the representation of knowledge of language in a language-independent manner, because such theories can make simultaneous communication of an item across different languages rather easy. But more research is required in this field before the relevant knowledge can be represented in a language-independent manner. Presently automatic and simultaneous communication of an item from any language to many other languages does not seem easy. However, it seems that in a very limited way a beginning can be made in the direction of such communication by human editors aided by tools developed by computer scientists so far. Revised and expanded version of a paper presented at the discussion meeting on “Artificial intelligence and expert system technologies in the Indian context” held at Indian Institute of Science, Bangalore, India, July 22–26, 1991 However, I alone am responsible for mistakes, if any, here.     

Structural synthesis under manufacturability constraints: A CAD system for the design of injection-molded product housings

We describe a computer-aided design system that automatically constructs the internal functional surface shapes of plastic injection molded product housings. Fundamental manufacturability constraints related to the geometry of injection mold parting and the solidification of molten plastic are identified. These constraints are embodied in structural synthesis operators that create the internal shapes given a set of functional requirements. An implementation, which is integrated with a system that automatically designs the external visible surface of the housing, is discussed. Algorithms for the structural synthesis operators are provided along with sample output demonstrating their operation.     

Formulation optimization and the absorption mechanisms of nanoemulsion in improving baicalin oral exposure

Objective: The aim of this study was to optimize baicalin nanoemulsion, clarify the absorption mechanisms of nanoemulsion improving the exposure of baicalin, and assess the potential of employing nanoemulsion as nanosystem for insoluble drugs.

Significance: A novel nanoemulsion formulation was successfully prepared to enhance oral exposure of baicalin.

Methods: Pseudo-ternary phase diagrams were utilized to evaluate nanoemulsion area. Physicochemical properties of optimal nanoemulsion formulation were investigated. The exposure of baicalin from the nanoemulsion was compared with baicalin suspension. The in situ single-pass intestine perfusion (SPIP) method and chylomicron-blocked rat model were used to study the absorption mechanisms of nanoemulsion.

Results: Baicalin nanoemulsion was nearly spherical in shape with the average droplet size of 58.43?nm, and the zeta potential was –8.18?±?1.2?mV. The stability test showed that baicalin nanoemulsion was very stable. Pharmacokinetic study indicated that baicalin nanoemulsion showed 14.56-fold improvement in exposure in comparison to baicalin suspension. The results of SPIP and chylomicron flow blocking study showed that intestinal absorption and lymphatic transport process contributed to its systemic exposure.

Conclusions: Based on the results, optimal nanoemulsion might be promising nanosystems for oral delivery of baicalin to satisfy clinical requirements.     

Effect of particle mass on the behavior of stochastic ratchets

Nonlinear Brownian motion in stochastic rachets is investigated by electronic simulation methods. It is shown experimentally that it is possible to sort particles by mass using a discrete random process, binary noise, as the source of the nonequilibrium stochastic ratchets. Pis’ma Zh. Tekh. Fiz. 24, 47–53 (January 26, 1998)     

Reducing the alkali cation adductions of oligonucleotides using sol-gel-assisted laser desorption/ionization mass spectrometry

The alkali cation adductions of oligonucleotides dramatically degrade MALDI mass spectra and even affect the detection limit. Desalting is generally involved in MALDI sample preparation. This work demonstrates the feasibility of using 3,4-diaminobenzoic acid (DABA) and 3,5-DABA as the MALDI matrix for oligonucleotide analysis. Furthermore, sodium ion adducts of oligonucleotides were simultaneously reduced in the mass spectra when DABA was used as the MALDI matrix and sol-gel material was used as the sample support. However, depositing the sample on the sample support was very difficult, and the lack of homogeneity of analytes/matrix distribution on the sample support also led the analyte signals to be revealed only in "sweet spots". Alternatively, DABA was doped into sol-gel materials to generate homogeneous DABA/sol-gel hybrid film. The DABA/sol-gel hybrid film was used as the sample substrate to assist the desorption/ ionization of analytes. The analyte signals were evenly found on the sample substrate. The sodium ion adductions of oligonucleotides were also effectively suppressed. The sample preparation used in this approach resembles that used in the authors' previous study, involving sol-gel-assisted laser desorption/ionization (SGALDI) mass spectrometry (Lin, Y.-S.; Chen, Y.-C. Anal Chem. 2002, 74, 5793-5798.) The SGALDI approach was demonstrated to be effective in assisting the desorption/ionization of peptides and small proteins. Herein, the SGALDI material, DABA/sol-gel hybrid material, was successfully applied to oligonucleotide analysis, and good-quality mass spectra were obtained without extra desalting. Additionally, the presence of 0.1% SDS in the oligonucleotide sample solution was tolerated without degrading the mass spectra. The largest detectable molecular size for oligonucleotides was 72 mer. The detection limit for 24 mer of oligonucleotide was 20 fmol.     

三元青铜/环境界面上物质转移的化学行为

用模拟闭塞电池法(O.C.)研究了青铜在模拟环境介质0.028 mol·L-1NaCl 0.01 mol·L-1Na2SO4 0.016 mol.L-1NaHCO3中的局部腐蚀孔内或裂纹内的化学变化.通电32 h后闭塞区内溶液的Ph值由7.00降至5.02,与此同时Cl-和SO24-向闭塞区内迁移,其浓集倍数分别是6.31和2.93;测定了闭塞区内外Cu、Sn、Pb金属离子的浓度,据此计算出溶解因子fsn/Cu小于1,fpb/Cu大于 1,表明青铜中各元素选择性腐蚀的顺序为Pb＞Cu＞Sn,腐蚀速度Pb＞Cu＞Sn;用XRD分析了腐蚀产物的组成,解释了青铜文物表面腐蚀产物的分层现象,即从里到外为CuCl,CuCl和Cu2O,Cu的二价化合物.     

Barriers to the adoption of green operational practices at Brazilian companies: effects on green and operational performance

The objective of this paper is to verify to what degree the internal and external barriers (I/EBs) to environmental management affect the adoption of green operational practices (GOPs) and to determine whether they influence the firms’ operational and green performance in a sample of Brazilian companies. A conceptual framework with 8 hypotheses is proposed and tested at 75 companies using Partial Least Squares-Structural Equation Modeling (PLS-SEM) with WarpPLS 4.0. The main results show that (a) the proposed framework obtained an adequate statistical adjustment, (b) the internal barriers (IBs) are more significant than the EBs when adopting GOPs, (c) GOPs relate directly to the firms’ green and operational performance (OP), (d) the IBs also indirectly influence the firms’ green and OP and (e) the firm size does not significantly influence its green and OP. This work contributes to the literature by showing that companies which are looking for green competitive advantages should try to reduce their IBs. Also, policy-makers should pay attention not only to legislation that promotes ecological modernisation, but also to create a strong set of initiatives to overcome IBs, regardless of the size of the firms.     

Micellar electrokinetic capillary chromatography of acidic solutes: migration behavior and optimization strategies.

Micellar electrokinetic capillary chromatography (MECC) is suitable for the separation of mixtures of uncharged and charged solutes. In this paper, the migration behavior of acidic compounds in MECC is quantitatively described in terms of different models. These equations describe the relationships between the two migration parameters in MECC (retention factor and mobility) and the two important experimental parameters (pH and micelle concentration) that have a great influence on the migration behavior and selectivity. Interestingly, the mobility and retention factor of a given solute could behave differently with the variations in pH. This would raise a question of which parameter actually represents the migration behavior of a solute in MECC: retention factor (a chromatographic parameter) or mobility (an electrophoretic parameter). The consequences of micellar-mediated shifts of ionization constants on selectivity and optimization strategies in MECC are discussed. The mathematical models would allow the prediction of migration behavior of solutes based on a limited number of initial experiments. This would greatly facilitate the method development and optimization of separations of ionizable compounds by MECC and, in addition, important physical and chemical characteristics of solutes such as their apparent ionization constants in micellar media and their partition coefficients into micelles (over a wide range pH values) can be determined. The models were verified, as good agreements were observed between the predicted and the experimentally observed migration behavior. Based on the preliminary results, the pH and micelle concentration are likely to be interactive parameters in many situations. As a result, simultaneous optimization of these two parameters would be the most effective strategy to enhance the MECC separation of acidic solutes.     

Reducing the absorbed dose in analogue radiography of infant chest images by improving the image quality, using image processing techniques

Radiographic inspection is one of the most widely employed techniques for medical testing methods. Because of poor contrast and high un-sharpness of radiographic image quality in films, converting radiographs to a digital format and using further digital image processing is the best method of enhancing the image quality and assisting the interpreter in their evaluation. In this research work, radiographic films of 70 infant chest images with different sizes of defects were selected. To digitise the chest images and employ image processing the two algorithms (i) spatial domain and (ii) frequency domain techniques were used. The MATLAB environment was selected for processing in the digital format. Our results showed that by using these two techniques, the defects with small dimensions are detectable. Therefore, these suggested techniques may help medical specialists to diagnose the defects in the primary stages and help to prevent more repeat X-ray examination of paediatric patients.     

Array of chemically etched fused-silica emitters for improving the sensitivity and quantitation of electrospray ionization mass spectrometry

An array of emitters has been developed for increasing the sensitivity of electrospray ionization mass spectrometry (ESI-MS). The linear array consists of 19 chemically etched fused-silica capillaries arranged with 500 microm (center-to-center) spacing. The multiemitter device has a low dead volume to facilitate coupling to capillary liquid chromatography (LC) separations. The high aspect ratio of the emitters enables operation at flow rates as low as 20 nL/min/emitter, effectively extending the benefits of nanoelectrospray to higher flow rate analyses. To accommodate the larger ion current produced by the emitter array, a multicapillary inlet to the mass spectrometer was also constructed. The inlet, which matched the dimensions of the emitter array, preserved ion transmission efficiency. Standard reserpine solutions of varying concentration were electrosprayed at 1 microL/min using the multiemitter/multi-inlet combination, and the results were compared to those from a standard, single-emitter configuration. A 9-fold sensitivity enhancement was observed for the multiemitter relative to the single emitter. A bovine serum albumin tryptic digest was also analyzed, and a sensitivity increase ranging from 2.4- to 12.3-fold for the detected tryptic peptides resulted; the varying response was attributed to reduced ion suppression under the nanoESI conditions afforded by the emitter array. An equimolar mixture of leucine enkephalin and maltopentaose was studied to verify that ion suppression is indeed reduced for the multiplexed ESI (multi-ESI) array relative to a single emitter over a range of flow rates.     

Intentions and willingness to drive while drowsy among university students: An application of an extended theory of planned behavior model

A web-based questionnaire was used to assess the utility of constructs from the Theory of Planned Behavior (TPB) and the Prototype Willingness Model (PWM) to predict intentions and willingness to engage in drowsy driving in a sample of 450 university students. Those students who reported more favorable attitudes and subjective norm and greater perceived control and willingness in relation to drowsy driving behavior were more likely to report stronger intentions to engage in drowsy driving behavior. Augmenting the TPB constructs with the PWM construct of willingness significantly explained up to an additional 8 percent of the variance in drowsy driving intention. Perceived behavioral control and willingness were consistently the strongest predictors of drowsy driving intention in the augmented model, which together with the control (personal) variables explained up to 70 percent of the variance in intention. Thus, the Theory of Planned Behavior and the Prototype Willingness Model may be useful for understanding motivational influences on drowsy driving behavior in young people and present promising theoretical frameworks for designing more effective interventions against drowsy driving in this population.