Low Distortion Quick Response Noise Filter Realized with Average Peaks Method

The filter proposed in this paper is expected to reduce noise whose frequency is lower than higher order harmonics of real signals. It is based on the distributive characteristics of noise, and uses analog circuits to select the high peak and low peak of the input signal and applies their average in order to reduce random noise. So it has no cutoff frequency and higher order harmonics of real signals are remained. As a result, it gives an instant response to changes in input signals and retains the integrity of real signals. Furthermore, it has only a small phase delay. The simulation results of slew rate, phase delay and spectral analysis under MULTISIM indicate that the quick response noise filter achieves a high slew rate of 472 V/ms and the phase shift is nearly zero. By having it used in a color tester design, it is also demonstrated that the proposed filter effectively reduces noise and remains signal integrity. With the filter’s help, the relative standard deviation of the spectrograph decreases from 1% to 0.22%, indicating better stability.     

Pseudo software: A mediating instrument for modeling software requirements

A new synthesis of software requirements models called pseudo software is proposed with the aim to cut requirements-related errors. Pseudo software achieves this aim by serving as a mediating instrument to empower stakeholders to participate in requirements elicitation and validation through model construction and manipulation, and to provide guidance to the development team to correctly interpret the requirements in the downstream development activities. Pseudo software obtains its traits as a mediating instrument through the choice of requirements information bits and the use of multimodal representations with tool support to integrate the requirements. Using historical data of fifty projects in the enterprise computing domain, pseudo software is shown to effectively cut the requirements-related errors committed by both the customer and the development team.     

EFFECT OF THE DISTRIBUTION OF PYRIDINE 1-OXIDE ON ITS CATALYZED TWO-PHASE REACTION OF BENZOYL CHLORIDE AND CARBOXYLATE ION

Benzoyl chloride (PhCOCl) exhibits a peculiar inhibitve effect on its reaction with some sodium carboxylates (RCOONa) catalyzed by pyridine I-oxide (PNO) in a CH₂Cl₂/H₂O medium. However, the reaction follows well the rate law -d[PhCOCl]_org/dt = K_obs[PhCOCl]_org = (k_h + k_c [PNO]_i.aq )[PhCOCl]_org. Where k_h is the uncatalyzed rate coefficient, k_c is the catalyzed rate coefficient, and [PNO]_i,aq is the initial concentration of PNO in aqueous phase. When the concentration of RCOONa is the sufficiently high, k_obs, can be expressed as k_obs, = k_h + kPNO[P-NO]_i,aq/(l + k_PNO) Where is k_PNO the intrinsic rate coefficient of the reaction between PhCOCl and PNO in CH₂Cl₂ and k_PNO is the distribution constant of PNO between H₂O/CH₂Cl₂ phases and is defined as k_PNO = [PNO]_aq/[PNO]_org. In order to account for this peculiar phenomenon, the effects of organic compounds, including CCl₄, alcohol, ester, and carboxylic acid, were investigated. The presence of organic additive affects the distribution of PNO between H₂O and CH₂Cl₂ phases, the reaction rate, and the yield of product. In general, the value of k_PNO correlated well with the effective concentration of free PNO in the CH₂Cl₂ phase. For the PNO-catalyzed reaction of PhCOCl and CH₃COONa in H₂O/CH₂Cl₂ medium, the main conclusions are:

(1)The presence of ROH additive in CH₂Cl₂ increases the distribution of PNO is CH₂Cl₂ and the value of k_PNO due to the hydrogen bonding between ROH and PNO.

(2)The presence of nonpolar CC1₄ and RCOOR' in CH₂Cl₂ decreases distribution of PNO and the values of k_PNO.

(3)The presence of RCOOH in CH₂Cl₂ enchances the distribution of PNO in CH₂Cl₂ and the value of k_PNO. However, the main product is PhCOOCOR instead of PhCOOCOCH₃ in contrast to the cases of adding ROH, CCl₄, and RCOOR'.     

Modeling of failure mode of laser welds in lap-shear specimens of HSLA steel sheets

Failure mode of laser welds in lap-shear specimens of high strength low alloy (HSLA) steel sheets is investigated in this paper. The experiments for laser welds in lap-shear specimens under quasi-static loading conditions are briefly reviewed first. The experimental results showed that the laser welds failed in a ductile necking/shear failure mode and the ductile failure was initiated at a distance away from the crack tip near the boundary of the base metal and heat affected zone. In order to understand the failure mode of these welds, finite element analyses under plane strain conditions were conducted to identify the effects of the different plastic behaviors of the base metal, heat affected zone, and weld zone as well as the weld geometry on the ductile failure. The results of the reference finite element analysis based on the homogenous material model show that the failure mode is most likely to be a middle surface shear failure mode in the weld. The results of the finite element analysis based on the multi-zone non-homogeneous material models show that the higher effective stress–plastic strain curves of the weld and heat affected zones and the geometry of the weld protrusion result in the necking/shear failure mode in the load carrying sheet. The results of another finite element analysis based on the non-homogeneous material model and the Gurson yield function for porous materials indicate that the consideration of void nucleation and growth is necessary to identify the ductile failure initiation site that matches well with the experimental observations. Finally, the results of this investigation indicate that the failure mode of the welds should be examined carefully and the necking/shear failure mode needs to be considered for development of failure or separation criteria for welds under more complex loading conditions.     

An RFID-based enterprise application integration framework for real-time management of dynamic manufacturing processes

Enterprise application integration (EAI) is an important issue for a company trying to transform itself into a ubiquitous real-time organization. However, traditional techniques for EAI are only suitable for integrating the virtual information among different applications. The challenge of integrating physical objects with corresponding business processes and applications at the right time and location is a critical concern for companies building a real-time enterprise (RTE) information system. In this research, we proposed an EAI framework based on radio frequency identification (RFID) technology. On the basis of this framework, a prototype system is developed to demonstrate the applicability of the framework in a shop floor environment. This paper also presents a RFID-based standard operation procedure to configure a prototype system for a particular shop floor operation and an operator orientation for performing the corresponding tasks. The findings of this paper demonstrate that the proposed framework is more capable than most current industrial practices in both managing dynamic manufacturing processes and in providing real-time visibility of work-in-process information. Using this framework, an enterprise can easily integrate an RFID-based solution into its IT infrastructure and manufacturing environment to facilitate real-time management of dynamic production operations.     

Complementary Kalman Filter as a Baseline Vector Estimator for GPS-Based Attitude Determination

The Global Positioning System (GPS) offers the interferometer for attitude determination by processing the carrier phase observables. By using carrier phase observables, the relative positioning is obtained in centimeter level. GPS interferometry has been firstly used in precise static relative positioning, and thereafter in kinematic positioning. The carrier phase differential GPS based on interferometer principles can solve for the antenna baseline vector, defined as the vector between the antenna designated master and one of the slave antennas, connected to a rigid body. Determining the unknown baseline vectors between the antennas sits at the heart of GPS-based attitude determination. The conventional solution of the baseline vectors based on least-squares approach is inherently noisy, which results in the noisy attitude solutions. In this article, the complementary Kalman filter (CKF) is employed for solving the baseline vector in the attitude determination mechanism to improve the performance, where the receiversatellite double differenced observable was utilized as the measurement. By using the carrier phase observables, the relative positioning is obtained in centimeter level. Employing the CKF provides several advantages, such as accuracy improvement, reliability enhancement, and real-time assurance. Simulation results based on the conventional method where the least-squares approach is involved, and the proposed method where the CKF is involved are compared and discussed.     

Support Vector Machine Assisted GPS Navigation in Limited Satellite Visibility

This paper investigates performance improvement via the incorporation of the support vector machine (SVM) into the vector tracking loop (VTL) for the Global Positioning System (GPS) in limited satellite visibility. Unlike the traditional scalar tracking loop (STL), the tracking and navigation modules in the VTL are not independent anymore since the user’s position can be determined by using the information from other satellites and can be predicted on the basis of the states of the user. The method proposed in this paper makes use of the SVM to bridge the GPS signal and prevent the error growth due to signal outage. Similar to the neural network, the SVM is motivated by its ability to approximate an unknown nonlinear input-output mapping through supervised training. The SVM is employed for predicting adequate numerical control oscillator (NCO) inputs, i.e., providing better prediction of residuals for the Doppler frequency and code phase in order to maintain regular operation of the navigation system. When the navigation processing is in good condition, the SVM is at the training stage, and the output information from the discriminator and navigation filter is adopted as the inputs. Other machine learning (ML) algorithms such as the radial basis function neural network (RBFNN) and the Adaptive Network-Based Fuzzy Inference System (ANFIS) are employed for comparison. Performance evaluation for the SVM assisted architecture as compared to the RBFNN- and ANFIS-assisted methods and the un-assisted VTL will be carried out and the performance evaluation during GPS signal outage will be presented. The proposed design is very useful for navigation during the environment of limited satellite visibility to effectively overcome the problem in the environment of GPS outage.     

STUDY OF THE REACTION OF GLYCINE AND BENZOYL CHLORIDE UNDER INVERSE PHASE TRANSFER CATALYSIS

This study examined the feasibility of reacting benzoyl chloride (PhCOCl) and sodium glycinate (H₂NCH₂COOH) catalyzed by 4-dimethylaminopyridine (DMAP) in an alkaline (NaOH) aqueous solution/dichloromethane two-phase medium. This catalyzed reaction of benzoyl chloride and sodium glycinate was described by a pseudo-first-order rate law. The hydrolysis of benzoyl chloride in the two*phase reaction was neglected on the specified reaction conditions. In addition, the effects of operating conditions on the conversion of benzoyl chloride and the reaction rate. According to those results, the reaction rate decreases with an increasing concentration of benzoyl chloride, which contradicts the general rate law of reaction kinetics, This peculiar phenomenon could be accounted for altering the interfacial property due to the change of the chemical property of reactants and intermediate, and the interaction between reactants and intermediate which was transferred from organic phase to aqueous phase.     

An engineering method for reliability analyses of mechanical structures for long fatigue lives

Reliability analyses of mechanical structures designed for long fatigue lives require: some information on the probability distribution of material fatigue strength at long fatigue lives. In order to address this need, three-parameter P-S-N curves are adopted to represent the results of fatigue tests based on the conventional method. The parameters of the P-S-N curves are estimated by using the least squares fitting method and maximizing the correlation coefficient. The three-parameter P-S-N curves obtained are then used to estimate the fatigue strengths for different survival probabilities at an arbitrarily long fatigue life. These fatigue strengths are used to define the probability distribution of fatigue strength at the long fatigue life when a normal. distribution is used to approximate the probability distribution of fatigue strength. The method is illustrated by analyzing the results of fatigue tests of steel #45 (Chinese steel) notched specimens subject to axial loads with a stress concentration factor k_t = 2·0. Then, the method is applied to the fatigue reliability analysis of the runner of a hydraulic turbine. It is shown here that the reliability at long lifetimes can be easily estimated by the proposed engineering method and the conventional method may give a non-conservative design at long fatigue lives due to the assumption of bi-linear P-S-N curves.     

Plane-stress crack-tip fields for perfectly plastic orthotropic materials

Plane stress mode I crack-tip fields for perfectly plastic orthotropic materials are studied. Plastic orthotropy is described by Hill's quadratic yield function. The construction of crack-tip fields is based on the general crack-tip field analysis for elastic perfectly plastic materials given by Rice [1] and guided by the corresponding low-hardening power-law solutions. Two very different types of plane-stress crack-tip fields emerge as plastic orthotropy is varied. The first one consists of a centered fan sector in front of the crack tip and two neighboring constant stress sectors. The second one consists of a constant stress sector in front of the crack tip, a constant stress sector bordering the crack face, and a centered fan sector between the two constant stress sectors. All the perfectly plastic crack-tip solutons are verified by the corresponding low-hardening power-law solutions. General trends of crack-tip stress solutions as functions of plastic orthotropy and implications of these solutions to the design of ductile composite materials are discussed.

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Résumé On étudie les champs de contraintes planes de mode I à l'extrémité d'une fissure, dans les matériaux orthotropiques parfaitement plastique. L'orthotropie plastique est décrite par la fonction quadratique de plasticité de Hill. On base les constructions des champs de constraintes sur l'analyse générale des constraintes à l'extrémité d'une fissure fournie par Rice pour les matériaux élastiques parfaitement plastiques, que l'on règle par les lois paraboliques caractérisant un faible écrouissage. Lorsque l'on modifie l'orthotropie plastique, il apparaît deux types de champs de contraintes à l'extrémité de la fissure très différents. Le premier comporte un secteur en éventail centré sur le front de fissure, et deux secteurs voisins à contraintes constantes. Le second consiste en une secteur à contrainte au bord de la surface de la fissure, et un secteur en éventail centré sur les deux secteurs à contraintes constantes. Toutes les solutions relatives à une extrémité de fissures parfaitement plastique sont vérifiées par les fonctions paraboliques d'écrouissage faible correspondantes. On discute des tendances générales que suivent les solutions pour les contraintes en extrémité de fissure selon l'orthrotropie plastique, et des implications que comportent ces solutions dans la conception de matériaux composites ductiles.