The Analysis of Sample-Based Music

In the design of the sequential probability ratio test (SPRT) chart, it is customary to adopt a set of prescribed process parameters (i.e., process mean and standard deviation). In recent years, there has been increasing consensus on the importance of investigating performances of the control charts assuming that the process parameters are unknown. This leads to the norm of estimating in-control process parameters from the historical Phase-I data set, and applying them in place of the true mean and standard deviation of the process data. Nonetheless, the use of estimated in-control process parameters is shown to have negative consequences on control chart's performances, especially when the Phase-I data is limited. In this paper, we provide a fresh look at the SPRT chart with estimated process parameters, both when the processes are out-of-control and in-control. We analyze the performances of the SPRT chart with known and estimated process parameters, as well as provide concise insights from three different perspectives. Results show that, when the Phase-I sample size and process mean shift are small, the average and standard deviation of the time to signal tend to vary considerably from those with known process parameters. Besides, we notice that the in-control performances of the SPRT chart with estimated process parameters worsen when a large inspection rate is used. Therefore, we recommend using a large number of Phase-I samples in parameter estimation and/or a small inspection rate to attain desirable chart's performances.

In this paper, the exponentially weighted moving average (EWMA) chart when the process parameters are unknown is studied. Under such circumstances, the process parameters are estimated from an in-control Phase-I dataset. Since the run length distribution of EWMA chart is skewed to the right, interpretation based on average run length (ARL) does not provide meaningful information about the chart's performance. On the contrary, the median run length (MRL) provides more useful interpretation. Thus, MRL will be used to assess the performance of the EWMA chart when process parameters are known and estimated. In this study, it is found that the out-of-control and in-control performances are severely affected by parameter estimation, especially when the sample size and process mean shifts are small. Moreover, a large number of in-control Phase-I samples is required so that the EWMA chart with estimated process parameters attains satisfactory performances as its known process parameters counterpart.

Selective Laser Sintering (SLS) is considered as one of the most important additive manufacturing processes due to component stability and its broad range of usable materials. However the influence of the different process parameters on mechanical workpiece properties is still poorly studied, leading to the fact that further optimization is necessary to increase workpiece quality. In order to investigate the impact of various process parameters, laboratory experiments are implemented to improve the understanding of the SLS limitations and advantages on an educational level. Experiments are based on two different workstations, used to teach students the fundamentals of SLS. First of all a 50 W CO₂ laser workstation is used to investigate the interaction of the laser beam with the used material in accordance with varied process parameters to analyze a single-layered test piece. Second of all the FORMIGA P110 laser sintering system from EOS is used to print different 3D test pieces in dependence on various process parameters. Finally quality attributes are tested including warpage, dimension accuracy or tensile strength. For dimension measurements and evaluation of the surface structure a telecentric lens in combination with a camera is used. A tensile test machine allows testing of the tensile strength and the interpreting of stress-strain curves. The developed laboratory experiments are suitable to teach students the influence of processing parameters. In this context they will be able to optimize the input parameters depending on the component which has to be manufactured and to increase the overall quality of the final workpiece.

Additive manufacturing technology is the process in which material is manufactured using different additive processes. There are many additive processes such as Stereo lithography (SLA), Selective laser sintering (SLS), Fused deposition modeling (FDM), etc. FDM is most popular additive manufacturing process in which parts are manufactured in layers. Among all additive manufacturing technology, FDM process is the most versatile additive manufacturing process due to low cost, flexibility, broad range in material, low time consumption and accessibility. FDM process is the most economical process compare to other additive manufacturing processes. A study of wettability is basically depending on the process parameter such as layer thickness, build orientation, print speed and post processing method. In this research work, wettability of 3D printed PLA parts have been investigated at different raster angles.Additive manufacturing technology is the process in which material is manufactured using different additive processes. There are many additive processes such as Stereo lithography (SLA), Selective laser sintering (SLS), Fused deposition modeling (FDM), etc. FDM is most popular additive manufacturing process in which parts are manufactured in layers. Among all additive manufacturing technology, FDM process is the most versatile additive manufacturing process due to low cost, flexibility, broad range in material, low time consumption and accessibility. FDM process is the most economical process compare to other additive manufacturing processes. A study of wettability is basically depending on the process parameter such as layer thickness, build orientation, print speed and post processing method. In this research work, wettability of 3D printed PLA parts have been investigated at different raster angles.

The objective of this study is to analyze the main parameter setting in injection moulding that influenced the processing of selected thermoplastics components. The test sample used for this project was a hinge made from Polypropylene (PP). This sample was being utilised to analyse the parameters affecting the quality of plastic products, which were warpage and shrinkage. Computer-Aided Engineering (CAE) was applied through CadMould 3D-F simulation software. The processing parameters such as filling time, melt temperature, wall temperature and cooling time were selected to determine the quality of the product. By adopting Taguchi Method, the orthogonal array, Signal-to-Noise (S/N) ratio and Analysis of Variance (ANOVA) were used to find the optimum levels as well as to indicate the impact of the process parameters on warpage and shrinkage. The verification test was also performed to prove the effectiveness of Taguchi technique after the optimum levels of process parameters. The ANOVA results show that cooling time and wall temperature are found to be the most significant factors for shrinkage and warpage, with the contribution of 66.96% and 56.82% respectively. The verification test with the optimal settings shows that warpage were improved by about 0.4% and shrinkage with 4.2% improvement. These findings are useful for production engineer to determine optimal parameter during performing injection moulding on hinges products.

This paper studies on the prediction model of mechanical properties of aluminum profiles based on spatial division of sample process parameters, according to the process parameters of aluminum profiles processing and its corresponding product performance. The direct mapping relationship between process parameter subspace and product performance parameter space is established by using RBF neural network. It provides theoretical basis and solution for the mechanical properties prediction of aluminum profiles, optimization of process parameters and improvement of the quality.

Spray dried vaccine formulations might be an alternative to traditional lyophilized vaccines. Compared to lyophilization, spray drying is a fast and cheap process extensively used for drying biologicals. The current study provides an approach that utilizes Design of Experiments for spray drying process to stabilize whole inactivated influenza virus (WIV) vaccine. The approach included systematically screening and optimizing the spray drying process variables, determining the desired process parameters and predicting product quality parameters. The process parameters inlet air temperature, nozzle gas flow rate and feed flow rate and their effect on WIV vaccine powder characteristics such as particle size, residual moisture content (RMC) and powder yield were investigated. Vaccine powders with a broad range of physical characteristics (RMC 1.2–4.9%, particle size 2.4–8.5μm and powder yield 42–82%) were obtained. WIV showed no significant loss in antigenicity as revealed by hemagglutination test. Furthermore, descriptive models generated by DoE software could be used to determine and select (set) spray drying process parameter. This was used to generate a dried WIV powder with predefined (predicted) characteristics. Moreover, the spray dried vaccine powders retained their antigenic stability even after storage for 3 months at 60°C. The approach used here enabled the generation of a thermostable, antigenic WIV vaccine powder with desired physical characteristics that could be potentially used for pulmonary administration.

Spatial beam shaping has long been utilized to improve laser processes and has often generated spectacular improvements in the end results. Until recently the temporal shape of laser pulses has been limited by the design parameters of the laser cavities and shaping in the temporal domain has remained relatively unexplored. The advent of the MOPA fiber laser has opened the door to creating arbitrary temporal waveforms with shape, energy, and duration being entirely independent from the laser repetition rate and changeable “on the fly.” This new degree of freedom in the laser processing parameter space has not only enabled new and improved laser processes but provided a new tool to study the dynamics of the laser material interaction itself which can greatly speed process development. Furthermore having this flexibility allows a single laser to cover a range of process parameters that heretofore normally required using several separate laser systems. This flexibility has proven to be especially useful in the processing of materials for Photo-Voltaic (PV) applications. In this work we report on the application of temporal pulse shaping to CIGS P2 & P3 processing, CIGS P1 processing (molybdenum on glass), a-Silicon P1 processing (ZnO on glass), c-Silicon via hole drilling for emitter wrap through (EWT) and other processes using the PyroFlex 25 pulse programmable fiber laser. The temporal pulse shaping feature of the laser is demonstrated as a tool to probe the process dynamics and speed the determination of optimal process parameters. When applicable, results between the pulse shape of a traditional laser and an optimized laser pulse shapes are compared.Spatial beam shaping has long been utilized to improve laser processes and has often generated spectacular improvements in the end results. Until recently the temporal shape of laser pulses has been limited by the design parameters of the laser cavities and shaping in the temporal domain has remained relatively unexplored. The advent of the MOPA fiber laser has opened the door to creating arbitrary temporal waveforms with shape, energy, and duration being entirely independent from the laser repetition rate and changeable “on the fly.” This new degree of freedom in the laser processing parameter space has not only enabled new and improved laser processes but provided a new tool to study the dynamics of the laser material interaction itself which can greatly speed process development. Furthermore having this flexibility allows a single laser to cover a range of process parameters that heretofore normally required using several separate laser systems. This flexibility has proven to be especially useful in th...

During recent decades, different formulas have been developed to estimate longshore sediment transport rates through calibration using a wide variety of datasets, applicable for a range of particular wave and beach conditions. The equations that have shown the best capability to predict Bulk Longshore Sediment Transport Rate (BLSTR) are the formulas derived by CERC and by Kamphuis. In the present study, the five process parameters as used in the Kamphuis formula are accepted. The CERC formula includes only two of the five process parameters used in Kamphuis’ formula. A renewed optimization to derive the power of the five Kamphuis’ process parameters using an extensive dataset by Bayram was performed by Mil-Homens. In addition to this valuable effort, our contribution introduces two innovations. Firstly, the power coefficients of the five Kamphuis process parameters are optimized using a broad range of meta-heuristic algorithms. Secondly, the optimization is not based on the Bayram dataset as carefully collected and reviewed from published manuscripts but on a methodologically more homogeneous Iranian dataset acquired for port design and port management purposes. Independently from the results by Mil-Homens derived from the Bayram dataset, our study confirms these findings based on a totally different dataset. Specifically, the weaker impact of wave period and the stronger impact of the median grain diameter are in accordance with each other. The latter finding provides a stronger support for the mutual cancellation of the impact of slope and grain diameter in BLSTR, lending explanatory support to the CERC formula once beach slope and grain size are not known.

The results are presented with regard to experimental studies of dynamic strength characteristics of samples made of 12Cr18Ni10Ti steel powder. They were obtained through selective laser melting with various parameters of a technological process at shock-wave compression up to pressures of ~7 GPa. Critical parameters of a process, in addition to powder characteristics, include laser operating conditions: a laser spot diameter, laser power, a laser beam scanning velocity, as well as a powder layer thickness, protective atmosphere, etc. It has been demonstrated that an increase in the scan laser power and a decrease in a powder layer thickness bring about a decrease in a number of internal defects in initial structures of samples. The results are given, which compare strength characteristics of these steels with properties of steel produced by a traditional technique of hot rolling. Shock-wave experiments were carried out using a light gas gun-type facility, which makes it possible to accelerate flat impactors to speeds of ~700 m/s; internal wave processes in samples were reproduced when recording a rate of movement of the sample's free surface via a PDV laser interferometer; a degree of spall fracture was determined by the help of a metallographic analysis of samples recovered in tests. It has been showed that steel samples made through a selective laser melting technique have high spall strength and a lower degree of damage compared to hot-rolled steel under the same conditions of high-speed shock loading. According to the results of the metallographic studies, the presence of internal defects in initial structures of samples associated with a choice of operating conditions of a manufacturing process does not affect a degree of their spall damage. At the same time, a wave pattern of shock wave propagation differs significantly for samples with and without defects.

With the aim to investigate the influence of UV-assisted persulfate oxidation operating parameters (cation type in persulfate salt, persulfate concentration and initial pH), the empirical/modeling approach applying full factorial experimental design (FFD) combined with response surface methodology (RSM) and mechanistic modeling (MM) was used. The efficiency of UV-assisted persulfate oxidation as a wastewater treatment method and the dependence on the aforementioned process parameters was evaluated in the case study where an azo dye (C.I. Acid Orange 7—AO7) was used as a model pollutant in water matrix. The FFD matrix with three independent variables representing the studied process parameters established experimental combinations, on which the UV-assisted persulfate oxidation process response, the AO7 decolorization rate was determined and correlated using RSM over quadratic polynomial equations, i.e. RSM model. The significance and accuracy of the developed RSM model was evaluated on the basis of analysis of variance and obtained statistical parameters (R 2, F, p), used also to examine the influence of studied process parameters. It was determined that the persulfate salt is the most influential process parameter, followed by rather high combined influence of initial pH and cation type, indicating the practical implications regarding the cation type. The MM used to describe the UV-assisted persulfate oxidation system showed high accuracy in predicting the AO7 degradation monitored over several parameters (decolorization, degradation of naphthalene and benzene structures, as well as overall mineralization) as well as high flexibility covering the broad pH range of application set by different cation type ion the persulfate salt.

Prediction of tensile strength in FDM printed ABS parts using response surface methodology (RSM)

Hydrogen embrittlement (HE) is a serious and costly industrial problem that affects many commonly used structural metals. Given the wide range of service environments in which hydrogen may occur or be produced, this represents a very serious threat to the structural integrity of machinery and infrastructure in many industries. Despite having been studied for several decades, there is still little consensus regarding the underlying mechanisms for HE. Recently developed theoretical and experimental methods, which enable the evaluation of the influences of hydrogen on the mechanical behavior of metals at the nano-scale, are helping to elucidate new aspects of these mechanisms. However, an urgent need remains to develop tools for the prediction of the reliability and lifetime of materials and components affected by hydrogen. Critical to achieving this goal is the development of accurate descriptions of hydrogen–microstructure interactions under conditions relevant to those occurring in service. As these interactions occur at all length scales, this poses a true multiscale challenge (Fig. 1). The International Symposium on Multiscale Approaches to Hydrogen-Assisted Degradation of Metals at the TMS2014 Annual Meeting & Exhibition in San Diego, California organized with the aim of promoting the exchange of ideas and information regarding the application of cutting-edge theoretical and experimental methods to industrial problems involving hydrogen-assisted degradation of metals. A particular focus of the symposium was multiscale modeling (e.g., coupled atomistic, mesoscopic, and macroscopic descriptions of hydrogen transport and damage mechanisms) as well as integrated theoretical and experimental approaches to hydrogen– microstructure interactions (e.g., the application of experimental methods for model validation and determination of modeling parameters). The symposium brought together leading researchers in the field of HE, as well as representatives from a broad range of industries that provided vital insights into the impact of HE. A total of 32 presentations were given during the 4-day meeting. The following five articles are based on presentations that were selected to show the diversity of topics covered at the symposium. In the article ‘‘Hydrogen Embrittlement of PulsePlated Nickel,’’ Reese et al. provide an overview of an experimental program at Airbus Group, which is aimed at evaluating the susceptibility of pulse-plated (PP) Ni to HE. This material is used in the fabrication of the components for the ARIANE 5 launcher. Due to the nature of the PP process, some hydrogen may be incorporated into the material during deposition. Depending on the process parameters used, this hydrogen, in combination with residual stresses resulting from welding, may result in HE. Although this does not pose an immediate problem, there is a need to better understand the influences of microstructure and process parameters on the susceptibility of PP-Ni to HE. The study is part of a wider EU-funded program called ‘‘MultiHy’’ (Multiscale modelling of hydrogen embrittlement), which aims to develop advanced multiscale models to assist companies to better understand how HE occurs during manufacture and service. ‘‘Hydrogen Embrittlement of Ferritic Steels: Deformation and Failure Mechanisms and Challenges in the Oil and Gas Industry’’ by Srinivasan and Neeraj reviews recent and forthcoming publications in which the HE of two commonly used pipeline steels, X65 and X80, was investigated using advanced analytical techniques. Analysis of the deformation substructures under the fracture surfaces using transmission electron microscopy (TEM) and the observation of nanovoids on the fracture surfaces using high-resolution scanning electron microscopy (SEM) led the authors to propose that the mechanism for HE involves vacancy-induced nanovoid nucleation and growth. The results are JOM, Vol. 66, No. 8, 2014

A trial and error approach reflects the state of the art in reaction injection molding. Material and process parameters determine the “moldability” of a specific system in a particular application. The concept of “molding areas” on the critical parameters plane can be extended form thermoplastic injection molding (TIM) to reaction injection molding (RIM).In this work moldability diagrams for the filling and curing stages of a RIM process are obtained based on a simplified engineering approach. The key process parameters chosen for the filling stage are initial material temperature and filling time. In the curing stage, the critical parameters are considered to be mold wall temperature and demold time. Experimental results obtained on a laboratory‐scale RIM machine on a Crosslinking polyurethane system are used to check the validity of the predicted molding areas. The agreement obtained is satisfactory considering the broad range of processing parameters used.

Modelling of bubble breakage and coalescence in stirred and sparged bioreactor using the Euler-Lagrange approach