Quality Characteristic Parameters Research Articles

Integrated classification method of tight sandstone reservoir based on principal component analysis– simulated annealing genetic algorithm–fuzzy cluster means

In this research, an integrated classification method based on principal component analysis– simulated annealing genetic algorithm–fuzzy cluster means (PCA–SAGA–FCM) was proposed for the unsupervised classification of tight sandstone reservoirs which lack the prior information and core experiments. A variety of evaluation parameters were selected, including lithology characteristic parameters, poro-permeability quality characteristic parameters, engineering quality characteristic parameters, and pore structure characteristic parameters. The PCA was used to reduce the dimension of the evaluation parameters, and the low-dimensional data was used as input. The unsupervised reservoir classification of tight sandstone reservoir was carried out by the SAGA-FCM, the characteristics of reservoir at different categories were analyzed and compared with the lithological profiles. The analysis results of numerical simulation and actual logging data show that: 1) compared with FCM algorithm, SAGA–FCM has stronger stability and higher accuracy; 2) the proposed method can cluster the reservoir flexibly and effectively according to the degree of membership; 3) the results of reservoir integrated classification match well with the lithologic profile, which demonstrates the reliability of the classification method.

Resistance Spot-Welding of Dissimilar Metals, Medium Manganese TRIP Steel and DP590

Resistance spot-welding of dissimilar metals, medium manganese TRIP steel 7Mn and DP590, is carried out. The effects of single-pulse welding parameters and a double-pulse-tempering current on the quality characteristic parameters and mechanical properties of 7Mn/DP590 spot-welded joints are studied. The welding process parameters are optimized using the control variable method. The results show that the optimal process parameters under a single pulse are as follows: electrode pressure: 4.5 kN, welding current: 9 kA and welding time: 300 ms. The failure mode of the welding joint is partial pull-out failure (PF-TT). The welding parameters have great influence on the nugget diameter and thickness reduction. Expulsion, crack and shrinkage are displayed in the joint under high electrode pressure. Softening occurs in the heat-affected zone due to a strong halo effect in the single-pulse weld. The tempering zone on the DP590 side is 202.49 HV, which is the lowest hardness point, while the hardness of the nugget zone is 450 HV. The addition of the tempering current homogenizes the microstructure with different failure paths and eliminates the stress. The tensile shear force of the joint increases by 17.13%. The 7Mn Steel/DP590 resistance spot-welding joint is from the fusion line to the center of the nugget, and the microstructure is composed of plane crystal, cellular crystal, dendritic crystal and columnar crystal, in turn. The nugget zone is composed of lath martensite and a small amount of residual austenite. Fine quasi-spherical and lamellar interbedded cementites are formed in the tempering zone of the DP590-side heat-affected zone.

Understanding the concept of Taguchi Technique Optimization of Material Surface Roughness and Removal Rate for metals in CNC Turning Operation: A Review

The objective of present study is to reviews optimal setting of number of opportunities in research of influence of process parameters, tool geometry and cutting environment for different machining operations on metals and power consumption during turning of different kind of work material using various optimization techniques like Taguchi approach, genetic algorithm and RSM. Taguchi robust design technique using L., orthogonal array was used for experimental run reviews. ANOVA is also used to find significance and percentage contribution of parameters for quality characteristics.

Effect of Manufactured Sand with Different Quality on Chloride Penetration Resistance of High-Strength Recycled Concrete.

High–strength manufactured sand recycled aggregate concrete (MSRAC) prepared with manufactured sand (MS) and recycled coarse aggregate (RCA) is an effective way to reduce the consumption of natural aggregate resources and environmental impact of concrete industry. In this study, high–, medium– and low–quality MS, which were commercial MS local to Changzhou and 100% by volume of recycled coarse aggregate, were used to prepare MSRAC. The quality of MS was determined based on stone powder content, methylene blue value (MBV), crushing value and soundness as quality characteristic parameters. The variation laws of compressive strength and chloride penetration resistance of high–strength MSRAC with different rates of replacement and different qualities of MS were explored. The results showed that for medium– and low–quality MS, the compressive strength of the MSRAC increased first and then decreased with increasing rate of replacement. Conversely, for high–quality MS, the compressive strength gradually increased with increasing rate of replacement. The chloride diffusion coefficient of MSRAC increased with decreasing MS quality and increasing rate of replacement. The chloride diffusion coefficient of MSRAC basically met the specifications for 50–year and 100–year design working life when the chloride environmental action was D and E. To prepare high–strength MSRAC, high–quality MS can 100% replace RS (river sand), while rates of replacement of 50–75% for medium–quality MS or 25–50% for low–quality MS are proposed. Scanning Electron Microscope (SEM) images indicated that an appropriate amount of stone powder is able to improve the compressive strength of RAC, but excessive stone powder content and MBV are unfavorable to the compressive strength and chloride penetration resistance of RAC.

Analysis of the anti-vibration qualified rate of relay considering manual debugging process

As an important switching device, the relay’s mechanical resistance has been receiving much attention. However, the manual debugging process has an important impact on it. This article starts with the analysis of manual debugging factors that affect the anti-vibration qualification rate. The quality characteristic parameters of the debugging process and their thresholds that affect its anti-vibration qualification rate are obtained by designing contrast tests. Secondly, the object’s qualitative characteristic parameters and debugging parameters are constructed by a approximate calculation model based on the virtual prototype. Finally, the impact of manual debugging process on product quality characteristics is analyzed. And suggestions on the parameters to be controlled by manual debugging are given. The adjustors strictly control the parameters of the debugging process according to the above suggestions. And the current qualification rate of the product has been greatly improved. It shows that the research on the manual debugging process based on the anti-vibration qualification rate is great significant.

System Availability Modelling and Optimization considering Multigeneral Quality Characteristics

This paper analyzes the necessity that multigeneral quality characteristic parameters should be considered in availability modelling and optimization and then constructs an availability model including the indicators of reliability, maintainability, supportability, testability, and environmental factor. In the research process, it is assumed that the system has soft and hard failure mode, adopting mixed maintenance strategies, system delay time, and repair time, and test time are independent. On the basis of this, the single parameter, binary parameters, and multiparameters optimization were carried out with the maximum availability as the optimization function. Especially, the multiparameters availability optimization model in time dimension was designed based on particle swarm optimization. The design method was proved feasible through a numerical example, which can provide method support for the design and evaluation of general quality characteristic thresholds in the life cycle of a repairable system.

Multi-parameter optimization of rigid-flexible coupled elastic rod screening for moist coal

The method of rigid-flexible coupling screening is widely used in the classification of moist coal. A new design for the surface structure of the vibrating screen with elastic rod was proposed to further increase the screening efficiency. The velocity of the target elastic tube selected in the middle of screen surface at different positions under no-load and load conditions were studied. Then, the influence mechanism of operating parameters and coal quality characteristics were investigated. The experimental results showed that the target elastic tube ran at high speed in the first and third areas under no-load condition, while the target elastic tube ran at high speed in the first, second and fourth areas under load condition. When the optimal operating conditions were found to be an excitation frequency of 16.7 Hz, a screen body amplitude of 4.3 mm, and optimum coal quality characteristic parameters were a 6-0 mm fines fraction of 38%, an external moisture content of 11.19%, the screening efficiency was the best.

Experimental and Computational investigations on the quality characteristics of laser beam machined metal matrix composite reinforced with ZrO2 particles

The research work explores the parametric influence of laser input variables on surface roughness and heat affected zone width. The workpiece material used as metal matrix aluminum 5052 alloy reinforced with ZrO2 particles. The computational analysis has been carried out using finite element method by taking laser power and arc radius profiles as variables. The mathematical model has been generated using Box-Behnken method for the analysis of variance. The machined samples have been analyzed using optical microscope and surface tester for measurement of quality characteristics. It has been analyzed that the effect of interaction of parameters has significant effect on surface roughness and heat affected zone width. Moreover, the influence of laser cutting speed, quantity of reinforced particles and laser cut path profile proved to be significant parameters for quality characteristics. The von-misses stress and temperature values found to be highest in case of complex cutting profiles as compared to linear trajectories.

Study on the Hot Workability of SiCp/Al Composites Based on a Critical Strain Map

We used the isothermal compression test (conducted in a Gleeble-3500 system) to study the hot deformation behaviors of SiCp/Al composites over a wide range of temperatures (623-773 K) and strain rates (0.001-10 s−1). A 3D hot-processing map was constructed based on the Malas stability criteria and experimental data. An artificial neural network model of four hot work quality characteristic parameters (strain rate sensitivity m, its derivative m′, temperature sensitivity s, and its derivative s′) were established. A new hot-processing map, known as a hot-processing critical strain map, has been proposed based on the smallest strain prior to instability. Two optimized processing regions at 623-660 K, 0.05-0.075 s−1 and 720-773 K, 0.04-0.18 s−1 were determined based on this map.

Research on the effect of coverage rate on the surface quality in laser direct writing process

Direct writing technique is usually used in femtosecond laser two-photon micromachining. The size of the scanning step is an important factor affecting the surface quality and machining efficiency of micro devices. According to the mechanism of two-photon polymerization, combining the distribution function of light intensity and the free radical concentration theory, we establish the mathematical model of coverage of solidification unit, then analyze the effect of coverage on the machining quality and efficiency. Using the principle of exposure equivalence, we also obtained the analytic expressions of the relationship among the surface quality characteristic parameters of microdevices and the scanning step, and carried out the numerical simulation and experiment. The results show that the scanning step has little influence on the surface quality of the line when it is much smaller than the size of the solidification unit. However, with increasing scanning step, the smoothness of line surface is reduced rapidly, and the surface quality becomes much worse.

Determination of optimum conditions in forward osmosis using a combined Taguchi–neural approach

In this study, Taguchi–neural approach was used to find the real optimum condition for the forward osmosis (FO) groundwater desalination. The feed solution velocity, draw solution velocity, feed solution temperature, and draw solution temperature (denoted as A, B, C, and D, respectively) were chosen as operating parameters, whereas maximum reverse solute flux selectivity (RSFS), Jv/Js, was chosen as the response. In the first step, the Taguchi method was applied to evaluate the primary optimal condition. The effect of parameters on both an active layer facing feed solution (AL-FS) and an active layer facing draw solution (AL-DS) orientations were evolved according to L16 (44) orthogonal array. The primary optimal condition for AL-FS, i.e., A=40cm/min, B=30cm/min, C=25°C, D=55°C, and for AL-DS, A=20cm/min, B=40cm/min, C=25°C, D=55°C were obtained. Analysis of variance (ANOVA) was used to recognize the important parameters that could affect FO quality characteristics (Jv/Js). Statistically, draw solution temperature (55°C) was found to be the most important parameters for quality characteristics (maximum Jv/Js). In the second step, all experimental results of AL-FS and AL-DS were used to train the neural network. The trained neural networks were used to find real optimum parameter levels. For AL-FS, A=34cm/min, B=10cm/min, C=35°C, D=50°C, and for AL-DS, A=18cm/min, B=33cm/min, C=35°C, D=48°C were found to be the real optimum parameters. This study shows the possibility of optimizing the FO process proficiently using the Taguchi–neural network approach.

Distributions and Process Capability Control Charts for CPU and CPL Using Subgroup Information

Process capability analysis is a very well-known and widely accepted method of assessing the ability of a process to produce items within pre-assigned specification limits. Most of the process capability indices (PCI) available in literature are formulated in terms of the parameters of the concerned quality characteristics. However, since the actual values of these parameters are often unknown, their estimated values are used to evaluate the estimated capability of a process. One such estimation procedure may be to use the estimates of these parameters obtained from the corresponding control charts used to check the stability of the said process. In this article, we used this approach to redefine plug-in (natural) estimators of the two most famous PCI’s for unilateral specification limits viz., CPU and CPL. We formulated the corresponding unbiased estimators and uniformly minimum variance unbiased estimators (UMVUE), wherever possible, and their distributions as well. We also designed the process capability control charts of CPU and CPL based on these UMVUEs. For constructing these control charts, we used the estimators of the parameters of the quality characteristics as obtained from the corresponding and charts. These charts can be used to check the consistency of capability of a process and also to keep a constant vigil on the process. Two numerical examples have been discussed and it has been observed that our proposed process capability control charts are more efficient to detect changes in process capability than those already available in literature.

Optimization Parameters of Femtosecond Laser Isolation Processing for a Microcrystalline Silicon Thin Film Solar Cell

This study explored the isolation process of a laser used to scribe the thin film layers of a microcrystalline silicon thin film solar cell. Using the Taguchi quality design, this study employed an L 18 orthogonal array to plan and implement an experiment for an isolation scribing process using a femtosecond laser. The isolation scribing materials included ZnO:Al, 500 nm–thick AZO transparent conductive thin film, 500 nm–thick microcrystalline silicon thin film with 38% crystallinity, and 300 nm–thick aluminum back-contact film. The results indicated that the fair processing quality characteristics included the minimum scribing line width, the flattest trough bottom, and the least number of surface bumps on the processing edge. The optimal single quality characteristic parameters of the Taguchi quality design were obtained using main effect analysis and the analysis of variance (ANOVA). The analytic hierarchy process (AHP) theory was applied to determine the optimal parameters for the multiple quality characteristics of the isolation scribing process. When the integrated isolation scribing line width of various layers was thinner, the area occupied on the solar cell was smaller, thus directly enhancing the photoelectric efficiency of the solar cell.

A hybrid genetic – Neural algorithm for modeling the biodegradation process of DnBP in AAO system

A hybrid artificial neural network – genetic algorithm numerical technique was successfully developed to model, and to simulate the biodegradation process of di-n-butyl phthalate in an anaerobic/anoxic/oxic (AAO) system. The fate of DnBP was investigated, and a removal kinetic model including sorption and biodegradation was formulated. To correlate the experimental data with available models or some modified empirical equations, the steady state model equations describing the biodegradation process have been solved using genetic algorithm (GA) and artificial neural network (ANN) from the water quality characteristic parameters. Compared with the kinetic model, the performance of the GA–ANN for modeling the DnBP was found to be more impressive. The results show that the predicted values well fit measured concentrations, which was also supported by the relatively low RMSE (0.2724), MAPE (3.6137) and MSE (0.0742)and very high R (0.9859) values, and which illustrates the GA–ANN model predicting effluent DnBP more accurately than the mechanism model forecasting.

Prediction model of DnBP degradation based on BP neural network in AAO system

A laboratory-scale anaerobic–anoxic–oxic (AAO) system was established to investigate the fate of DnBP. A removal kinetic model including sorption and biodegradation was formulated, and kinetic parameters were evaluated with batch experiments under anaerobic, anoxic, oxic conditions. However, it is highly complex and is difficult to confirm the kinetic parameters using conventional mathematical modeling. To correlate the experimental data with available models or some modified empirical equations, an artificial neural network model based on multilayered partial recurrent back propagation (BP) algorithm was applied for the biodegradation of DnBP from the water quality characteristic parameters. Compared to the kinetic model, the performance of the network for modeling DnBP is found to be more impressive. The results showed that the biggest relative error of BP network prediction model was 9.95%, while the kinetic model was 14.52%, which illustrates BP model predicting effluent DnBP more accurately than kinetic model forecasting.

Optimization of quality characteristics parameters in a pulsed metal inert gas welding process using grey-based Taguchi method

Optimization of a manufacturing process has to take into accounts all of the factors that influence the product quality and productivity. Optimization of welding process parameters is considerably complex because welding is a multi-variable process, which is influenced by a lot of process uncertainties. In this paper, a grey-based Taguchi method has been adopted to optimize the pulsed metal inert gas welding process parameters. Many quality characteristic parameters are combined into one integrated quality parameter by using grey relational grade or rank. The welding process parameters considered in this analysis are pulse voltage, background voltage, pulse frequency, pulse duty factor, wire feed rate, and table feed rate. The quality parameters considered are the tensile strength, bead geometry, transverse shrinkage, angular distortion, and deposition efficiency. Analysis of variance has been performed to find out the impact of individual process parameter on the quality parameters. If the tensile strength as the most important quality parameter is assigned a higher weight, then the pulse voltage was found to be the most influential process parameter. Experiments with the optimized parameter settings, which have been obtained from the analysis, are given to validate the results.

Determining the optimal process means under mixture normal distributions

In this paper, we consider that the working environment has certain states, and in every state, the parameters of quality characteristics are different. Thus, if we set the characteristics parameters in a specified state, these parameters will change to another state. To describe this situation, we use a mixture of normal distributions, which comprise a flexible and powerful statistical-based modeling tool in practice. Under the step loss function and the piecewise linear loss function, we select the optimal means for the proposed manufacturing process.

The beam quality of annular lasers and related problems

A detailed study of the beam quality of annular lasers, for example, lasers with or without phase distortions emitted from unstable resonators, is made, where the power in the bucket (PIB) and β-parameter are chosen as criteria for characterizing the beam quality in the far field. It is shown that better focusability is achieved at the real focal plane rather than at the geometrical focal plane due to the focal shift, and the negative quartic phase distortions may improve the beam quality measured in terms of the PIB and/or β-parameter. From a practical point of view the PIB and β can be chosen as beam quality characteristic parameters for such lasers. However, some related problems remain, which are discussed briefly.