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Chatter is a kind of self-excited, unstable vibration in almost all machining processes. Existing studies have been focusing on the pre-chatter stage, developing various techniques to detect, predict, and suppress chatter. In real applications, chatter will inevitably happen under certain cutting conditions, with generating chatter marks on the workpiece surface. Additional operations are required to remove chatter marks before the finish machining. It is noted that chatter marks will easily induce chatter again, resulting in worse surface quality. This paper quantitatively analyzes the effects of chatter marks on the stability of the process by modeling chatter marks with a periodically modulated depth of cut. Stability lobes show that the existence of chatter marks greatly reduces the stability limit. Furthermore, chatter mark removal using spindle speed variation (SSV) is proposed. Extended high-order full-discretization method using Lagrange interpolation is developed to analyze the effect of SSV on chatter marks removal. It is shown that SSV can remarkably improve the stability limit even with chatter marks. Finally, machining experiments of thin-walled discs are conducted to verify the deterioration effect of chatter marks on the stability limit and show that chatter marks can be effectively removed by the SSV. [ABSTRACT FROM AUTHOR]

The bridge influence line (IL) is widely used in structural evaluation, damage identification, model updating, and other applications. The IL curve of an existing bridge is usually different from its designed value. It is crucial, yet challenging, to detect the actual bridge IL by measurement. In this paper, a fitting method is proposed for extracting the bridge IL from the dynamic response induced by a passing vehicle. Based on the theoretical mechanism of bridge IL under different boundary conditions, along with the features of bridge vibration, a piecewise polynomial and a series of harmonic sinusoids are established to describe the IL of the measured point and the fluctuation part of the bridge response, respectively. A mixed function obtained by linear superposition of these factors is utilized to fit the bridge dynamic response. The coefficients of the piecewise polynomial can be extracted by a least-square calculation; and subsequently, the actual IL curve of the measure point of the bridge is obtained. Numerical examples of vehicle-bridge models are adopted to validate the fitting method of IL extraction proposed in this paper, and to illustrate the efficiency by comparing it with the existing direct inverse calculation method. The validity and feasibility of this method are also demonstrated by both a laboratory experiment and a field test. [ABSTRACT FROM AUTHOR]

A theory program intended for use with extended X-ray-absorption fine structure (EXAFS) spectroscopy and based on the popular FEFF8 is presented. It provides an application programming interface designed to make it easy to integrate high-quality theory into EXAFS analysis software. This new code is then used to examine the impact of self-consistent scattering potentials on EXAFS data analysis by methodical testing of theoretical fitting standards against a curated suite of measured EXAFS data. For each data set, the results of a fit are compared using a well characterized structural model and theoretical fitting standards computed both with and without self-consistent potentials. It is demonstrated that the use of self-consistent potentials has scant impact on the results of the EXAFS analysis. [ABSTRACT FROM AUTHOR]

Inconel 718 is one of the most difficult to cut material due to its, high hardness, high toughness, and poor thermal conductivity results in heat concentrated in the cutting zone, making it ineffective to be processed through conventional machining. So usually, an electrical discharge machining (EDM) is chosen in order to overcome such limitations. However, EDM is known as a slow machining process. Thus, by employing powder mixed in the dielectric fluid it is believe to enhance the machining efficiency. To achieve high performance in EDM for this research, higher peak current, Ip up to 40A, pulse duration, ton up to 400μs and powder concentration, Cp up to 4g/l were selected as the main parameters. Copper tungsten (CuW) was used as an electrode. The circulating dielectric system called High Performance EDM (HPEDM) was applied to conduct the experiment involving powder mixed dielectric. Their influence on the machinabilities of the material removal rate (MRR), and electrode wear rate (EWR), were experimentally investigated. The surface topography of the machined work piece and surface morphology of the electrode also have been observed. The results have shown that, at a highest Ip=40A and the lowest ton=200μs with Cp=4g/l yields the highest MRR. The improvement is almost 50% when comparing without powder concentration at the same parameter settings. In the case of EWR, lowest value of EWR was obtained at Ip=20A, ton=400μs and Cp=0g/l. [ABSTRACT FROM AUTHOR]

This paper introduces and discusses the Rotation and Revolution Polishing (RRP) method which meets increasing demands for high quality aspherical optics and higher precision polishing techniques by its unique machining positions and tool shapes. The RRP method is a promising precision polishing method as it can stably maintain polishing tool shapes and uniformly generate the surface roughness by through optimum polishing velocity distribution. Experiments were conducted to determine and prove the of effectiveness of mathematic models on polished profiles based on the Preston equation under diverse conditions. [ABSTRACT FROM AUTHOR]

A mixed ceramic is a type of cutting-tool material widely employed for machining hardened steels. The usage of a mixed ceramic along with a wiper geometry can help double the feed rate, thereby increasing productivity while keeping the surface roughness ( Ra ) as low as possible. Analyses of manufacturing processes, such as a machining process, show that the various possible controlled parameters can be modeled by multiobjective mathematical models to ensure their optimization. Hence, the aim of this study was optimize a hard turning process using a robust weighting based on diversity to choose the final Pareto optimal solution of the multiobjective problem. The responses of the material removal rate ( MRR ), Ra parameter, and cutting force ( Fc ) were modeled by using the response surface methodology; in this methodology, decision variables, such as the cutting speed ( Vc ), feed rate ( f ), and depth of cut ( d ), are employed. The diversity index, as a decision-making criterion, proved to be useful in mapping the regions of minimum variance within the Pareto optimal responses obtained in the optimization process. Hence, the study demonstrates that the weights used in the multiobjective optimization process influence the prediction variance of the obtained response. [ABSTRACT FROM AUTHOR]

With the development of precision and ultra-precision machining technology, the demand of drive feed system increases. Non-linear friction in a conventional drive feed system (CDFS) feeding at low speed is one of the main factors that lead to the complexity of the feed drive. The CDFS will inevitably enter or approach a non-linear creeping area at extremely low speed. A novel two-axis differential micro-feed system (TDMS) is developed in this paper to overcome the accuracy limitation of CDFS. A dynamic model of TDMS is first established. Then, a distributed component friction parameter identification method using a genetic algorithm (GA) to identify the friction parameters of a TDMS is introduced. A proportional-derivate feed drive position controller with an observer-based friction compensator is implemented to achieve an accurate trajectory tracking performance. Finally, comparative experiments demonstrate the effectiveness of the TDMS in inhibiting the disadvantageous influence of non-linear friction and the validity of the proposed identification method for TDMS. [ABSTRACT FROM AUTHOR]

In this paper, we present a recent evolution of the analytical form of the Gogny force. The extension of the density-dependent term to a finite range is discussed and has led to the D2 Gogny force. A global refitting of the force has been done but preserving standard good properties of the Gogny force. Indeed the same fitting procedure with the same constraints and filters which have been used to obtain the D1-type parametrizations has been applied. The evolution of global properties (binding energies and nuclear radii) along the N = 8, 20, 28, 40 isotopic chains is discussed at the Hartree-Fock-Bogoliubov approximation level. Results coming from systematic calculations based on 1385 nuclei are also presented. Axial symmetry has been assumed. A comparison with the results obtained using the D1S parametrization, which tends to show that the D2 and the D1S Gogny force display very similar axial deformation properties, is done. [ABSTRACT FROM AUTHOR]

This study integrated the removal mechanisms of electrical discharge machining (EDM) in gas and ultrasonic vibration to explore the benefits of the developed hybrid process in improving the machining characteristics. The developed hybrid process was adopted to determine the machining performances for SKD 61 steel through the experimental investigation. It is well known that using kerosene as a dielectric fluid in EDM would evoke the undesirable problems like fire hazard, air pollution, and environmental damage. In this study, the air, oxygen, and argon gas media were employed in the experiments to investigate the effects on material removal efficiency, surface integrity, and thickness of recast layer. The experimental results show that the hybrid process obtained higher material removal rate (MRR), lower electrode wear rate (EWR), and finer surface roughness (SR). In addition, the oxygen medium could facilitate the reaction within the machining gap to increase the exploding and melting effects. Thus, the MRR obtained by oxygen has the highest values. The argon was an inert gas that could prevent the oxidation during the process, and the lower EWR could be obtained using argon as a medium in the EDM process. The ultrasonic vibration incorporated in the process could effectively reduce the surface defects that were generated on the machined surface. Generally, the different gas media supplied into the machining area could create various mechanisms. The ultrasonic vibration incorporated into the process could also promote the machining performances of the developed hybrid process. [ABSTRACT FROM AUTHOR]

Enhanced single-patch NURBS (Non-uniform rational B-splines) parameterization is developed based on fitting parameter values, capable of handling dynamically changing shapes. With respect to NURBS and T-splines, the proposed single-patch parameterizations results in lower dimensionality enabling optimizers to operate on geometric parameters. Avoiding sub-division surfaces and continuity problems for piecewise NURBS and reparameterizations for T-splines accelerates optimization. This parameterization may be an approximation or initial solution for piecewise NURBS and T-splines. These numerical benefits are accomplished using a multi-stage methodology. An augmented set of fitting variables is formulated beyond the weight factors and control points with parameter values of data points. This augmented set is structured to possess reasonable dimensionality. The developed non-linear fitting includes gradient-based minimization with respect to the augmented set and evolutionary error minimization using external functions. The benefits and potential difficulties of the procedure are evaluated thoroughly. The methodology is tested on engineering objects of high shape complexity and demonstrated to provide superior single-patch fitting performance compared to standard linear fitting methods. The developed numerical approach provides for the aspired main objective which is sufficiently accurate and numerically efficient dynamic shape parameterizaton using a compact set of shape parameters. [ABSTRACT FROM AUTHOR]

A sequential micro-machining process chain is described as the machining strategy whereby two or more micro-machining techniques are implemented in sequence on same or different machine tools. This is in contrast to hybrid micro-machining where two standalone machining technologies are integrated together. A recent surge of interest is geared towards building sequential micro-machining capabilities on a single machine tool to avoid realignment errors. One of the major advantages of performing sequential micro-machining on a single machine tool is that it suppresses repositioning errors so enabling much higher levels of accuracy (and thereby tighter tolerances), reduced rejection of machined components, and lower production time; all of these would be otherwise unachievable. Thus, multifunctional micro-machining centres are attracting global interest. Clearly, the necessity of developing reconfigurable, precise and flexible manufacturing is a key driver to this trend. This review aims to provide a critical insight into the recent trends and new classification of sequential micro-machining processes with a special focus on evaluation of such capabilities built on a single machine tool and further potentials. The machining capabilities, advantages and opportunities in the area of sequential micro-machining techniques are evaluated thoroughly and the directions for future work are highlighted. [ABSTRACT FROM AUTHOR]

This study attempts to develop a micro-milling force model under cutting conditions considering tool flank wear effect during micro-milling of nickel-based superalloy with coated carbide micro-milling tools based on our three-dimensional dynamic cutting force prediction model established earlier. The tool wear condition in micro-milling nickel-based superalloy was obtained by finite element method. A 3D thermal-mechanical coupled simulation model for micro-milling nickel-based superalloy was developed to obtain the tool wear conditions and the distribution of stress. For the given tool geometries and machining conditions, the cutting forces considering tool flank wear effect could be determined conveniently. In addition, experiments of micro-milling nickel-based superalloy were conducted to estimate the validity of the modified model. The results showed that the proposed modified force analytical model could predict micro-milling cutting forces more accurately. [ABSTRACT FROM AUTHOR]

The approach of machining ceramics with electrical discharge machining process is a great challenge till date due to its low electrical conductivity. Machining is made possible by reinforcing with a conductive phase which increases the overall electrical conductivity. Present work focuses on machining of multi walled carbon nanotubes filled alumina composites. Samples with concentrations ranging from 2.5 to 12.5 vol.% are considered for machining. At lower concentration of 2.5 vol.%, effective machining is not possible. Wire lag phenomena is observed during machining at 5 vol.% sample concentration. Proper machinability is observed with concentration of 7.5 vol.% or more. Also, long micro-cracks are obtained during machining that leads to the workpiece breakage. Spalling effect is observed as the most dominating material removal mechanism. A comparison between alumina composites and conducting metallic alloys were carried out for surface characteristics. [ABSTRACT FROM AUTHOR]

Machining process is usually needed to fettle the assembly interfaces of large-scale component before the final assembly. There are several issues that make the process time and effort consuming, such as hard-to-machine material, difficulties in positioning and alignment, errors between as-built component, and as-designed model. Shop floor optimization is essential for machining this kind of large and complex workpiece but is limited by information loss from CAD/CAM to CNC (Computer Numerical Control) using traditional G&M codes. STEP-NC has been proven to perform excellently in data exchange between CAD/CAM and CNC but it does not support some special processes in machining the assembly interfaces. To solve these matters, this paper proposes a closed-loop machining system based on extended STEP-NC data models which cover aligning and laser tracker measuring process. The system consists of: (1) a STEP-NC compliant CAD/CAM system which exports STEP-NC programs, (2) a STEP-NC high-level process controller which translates STEP-NC programs and makes closed-loop optimization, and (3) CNCs and mechanical systems which perform machining and measuring tasks. In the end, a vertical tail of a large passenger plane is used as a study case to demonstrate the advantages of the proposed data models and systems. This paper contributes to machining the assembly interfaces of large-scale components, and the future development of STEP-NC in large-scale manufacturing. [ABSTRACT FROM AUTHOR]

The complexity of linear mixed-effects (LME) models means that traditional diagnostics are rendered less effective. This is due to a breakdown of asymptotic results, boundary issues, and visible patterns in residual plots that are introduced by the model fitting process. Some of these issues are well known and adjustments have been proposed. Working with LME models typically requires that the analyst keeps track of all the special circumstances that may arise. In this article, we illustrate a simpler but generally applicable approach to diagnosing LME models. We explain how to use new visual inference methods for these purposes. The approach provides a unified framework for diagnosing LME fits and for model selection. We illustrate the use of this approach on several commonly available datasets. A large-scale Amazon Turk study was used to validate the methods. R code is provided for the analyses. Supplementary materials for this article are available online. [ABSTRACT FROM PUBLISHER]

Large taper (≥ ± 5°) high-speed wire electrical discharge machining can be affected by many factors. The positioning error of wire electrode caused by guide wheels and the run-out of guide wheels are particularly important. Moreover, dielectric fluid cannot wrap the wire electrode appropriately and flow into the machining region along with the wire electrode in tilt directions. As a result, the machining accuracy and surface roughness of a large taper-cutting workpiece are worse than those of straight cutting. In order to solve these problems, this paper presents the design and improvement of two types of six-bar linkage large taper-cutting mechanisms that can realize the guide of wire electrode and the tracking spray of dielectric fluid along with the incline of the wire electrode. The first type causes angular error but no wear, whereas the second one causes wear but no angular error. The former is applied to process experiments. The experimental results show that, compared with traditional mechanisms, this new approach decreases the roundness error of the workpiece from 80 to 40 μm and the surface roughness from 4.059 to 3.495 μm under the same processing parameters. In terms of multi cutting (skim cutting), the new mechanism reduces the roundness error of taper cutting (taper ±20°, thickness 40 mm) to 25 μm and the surface roughness to 1.670 μm. An idea of intelligent servo traverse guider based on this mechanism is also proposed in this study. [ABSTRACT FROM AUTHOR]

An efficient machining is limited by the chatter of machining system including spindle and support, which would cause poor surface quality. This paper proposed an improved stability prediction method based on the dynamics of machine tool. Dynamics of the support are considered into the stability prediction of machining process. The spindle was modeled by the receptance coupling substructure analysis method to predict the dynamics at the tool point. The mathematical model of the closed manufacturing system (machine tool, spindle, holder, and tool) was given, as well as the details of joint contacts. The model was used to obtain the system characteristics, and the FRFs of the tool point were obtained from the model in frequency domain. Moreover, the stability limitation for machining system were developed to create the stability lobe diagram with the FRFs of both the spindle and support. Experimental results showed that the depths of improved stability lobes were smaller than those of the original ones, and the improved lobes were more accurate for the stability predictions. The machined surface quality showed that the stable machining system was beneficial to produce good surface. This improved method is helpful for the stability calculation and machining parameter selection especially when milling a thin-walled workpiece or a weak clamping fixture. [ABSTRACT FROM AUTHOR]

Cleaner production and sustainability are of crucial importance in the field of machining processes where great amount of energy is being consumed. This paper outlines the application of gray relational theory in order to optimize the machining parameters for Ti6Al4V in high-speed dry electrical discharge milling (EDM) using a tubular graphite electrode. The objective of optimization is to achieve simultaneously the minimum power consumption and the maximum material removal rate (MRR). The maximum MRR 5634 mm/min was obtained with a power consumption of 7.61 kW. MRR stayed in the similar level, and power consumption was reduced by 17.82 % compared with that of the parameters in our previous study. Current is the main effect factor on MRR and power consumption. The corresponding single pulsed experiments were conducted to deeply explore the reasons for the influence of air pressure and electrode rotation speed on the MRR and power consumption. [ABSTRACT FROM AUTHOR]

Machining accuracy is a very important index to measure the performance of NC machine tools, and how to improve the machining accuracy grabs the attention of both manufacturers and users. Since the geometric errors are intercoupling and are one of the main factors affecting machining accuracy of machine tools, in this paper, a new method for extracting key geometric errors based on the screw theory and extended Fourier amplitude sensitivity test (EFAST) method was proposed. First, screw theory was introduced, and the machining accuracy modeling of a three-axis vertical machining center (VMC) was established. Then, in order to analyze the coupling effects between geometric errors by high-dimensional nonlinear model, EFAST global sensitivity analysis method was adopted to help in extracting the main geometric errors. An illustration example on a three-axis VMC shows that the proposed method is effective and can be helpful to improve the geometric accuracy of machine tool. [ABSTRACT FROM AUTHOR]

Titanium alloy TB6 is often used to produce key load carrying parts in the aviation and aerospace industries. The superior mechanical properties pose challenges to machining processes, bringing about such problems as rapid tool wear. In this paper, fine-grain WC/Co tools were utilized in dry turning of the TB6 alloy. The wear modes and wear mechanisms of the cutting tools at different cutting speeds were detailed. The analysis showed that the wear on the tool rake face was characterized as crater formation. The principal wear mode observed on the tool flank face appeared to be microchipping near the region of the cutting edge. The adhesion was more pronounced on the rake face than on the flank face. The clusters of WC particles were pulled out from the Co binder along the grain boundaries, which led to adhesive wear and left an intergranular fractured surface. The crater wear was a result of the elements of the cutting tool diffusing into the adhering material, which was carried away by the flowing chip, leading to a transgranular dissolution of the WC particles, and the worn surface was smooth. The chemical reaction possibly took place at the tool/adhering material interface, where the newly formed compounds were carried away by the flowing chip. The hard particles that adhered to the back surface of the titanium chip probably abrade the tool surface, causing abrasive wear. [ABSTRACT FROM AUTHOR]

Microscale numerical modeling is currently the main tool used in wind industry to assess local wind resources. This paper presents a systematic procedure to adjust computational fluid dynamics (CFD) predicted wind profiles to experimental measurements in order to minimize their differences. It can be applied when wind measurements are available. Data from ten masts with several measurement heights from the well-known Bolund hill experiment provided the observed wind profiles. Simulated profiles were calculated with windsim CFD model for the aforementioned site. Speed-up correction factors were defined through the least squares method to cross-correlate each mast as reference to all the others inside the Bolund hill domain. After, the observed and the adjusted wind profiles at the same position were compared. Moreover, root mean square errors (RMSEs) were used as a metric to evaluate the estimations and the ability of each position to be predicted and predictor. Results have shown that the quality of the adjustment process depends on the flow characteristics at each position related to the incoming wind direction. Most affected positions, i.e., when the airflow overcomes the Bolund hill escarpment, present the less accurate wind profile estimations. The reference mast should be installed upstream of the potential wind turbines' locations and after the main local characteristics of topographical changes. [ABSTRACT FROM AUTHOR]

Droop schemes are usually applied to the control of distributed generators (DGs) in microgrids (MGs) to realize proportional power sharing. The objective might, however, not suit MGs well for economic reasons. Addressing that issue, this paper proposes an alternative droop scheme for reducing the total active generation costs (TAGC). Optimal economic operation, DGs' capacity limitations and system stability are fully considered basing on DGs' generation costs. The proposed scheme utilizes the frequency as a carrier to realize the decentralized economic operation of MGs without communication links. Moreover, a fitting method is applied to balance DGs' synchronous operation and economy. The effectiveness and performance of the proposed scheme are verified through simulations and experiments. [ABSTRACT FROM AUTHOR]

A rational determination of machining parameters of electrical discharge machining (EDM) is of vital importance to the machining quality. This paper proposes an ANSYS emulation, experimental correction, and numerical fitting method (AEN-XRD method) to determine the relationship between machining parameters and machining indicators of various kinds of machine tools. Firstly, it adopts ANSYS software to make simulation researches of the pit size with different electrical parameters. Theoretical calculation of corresponding machining indicators is presented. Based on the machine data, adjustment is made on the simulation outcome. And thereby, based on the adjusted outcome, numerical fitting method is adopted to determine the functional relation formula of machining parameters and machining indicators. Experiments of different machine tools have shown that there is a relatively high prediction accuracy of machining parameters and they are capable to meet the actual machining demand, which further proves the AEN-XRD method is of great practicability. [ABSTRACT FROM AUTHOR]

The wear response of tungsten carbide-iron aluminide (WC-FeAl) cutting tools was compared to that of conventional cemented carbide (WC-Co) tools when dry machining oxygen-free copper (Cu) round bars. Using flank wear width as a metric, it was found through machining tests that WC-FeAl cutting tools exhibited longer lifetimes (30% longer) than WC-Co ones with the same cutting distance. It was proposed that this finding resulted from the difference in oxidation resistance of binder materials (Co versus FeAl) against Cu. At the estimated temperature for cutting edge, Co was oxidized but FeAl was not. Furthermore, the oxidation of Co was enhanced with the presence of Cu which was not oxidized in itself. This apparent catalytic action by Cu was not seen in the case of FeAl. It was concluded that the tribo-oxidation characteristics of WC-FeAl cutting tools make them more effective for machining pure Cu than tools containing Co binders alone. [ABSTRACT FROM AUTHOR]

Objections against utilizing the peak fitting method in computing the kinetics parameters of thermoluminescence (TL) glow-peaks were discussed previously in the literature. These objections came through testing the accuracy of the peak fitting by applying on simulated peaks. The results showed that in some cases the simulated peaks may have unusual geometrical properties and do not reflect the real properties of TL peaks. Thereby, estimating the accuracy of the peak fitting by applying on such peaks would be misleading. Two main reasons may lead to unrealistic simulated peaks; the improper selection of the simulation inputs, and performing the TL simulation process via the heating stage only. It has been proved that considering the irradiation and the relaxation stages in the simulation process is crucial. However, there are other cases in which the analytical methods were not able to reveal the real values of the simulated peaks. These cases were successfully resolved using analytical expressions derived from the one trap-one recombination (OTOR) level model and the non-interactive multiple trap system (NMTS) model. A general conclusion can be drawn that the accuracy of the peak fitting method is critically dependent on the TL analytical expressions utilized in this method. The failure of this method in estimating the TL kinetic parameters should be attributed to the TL model equation utilized in fitting process. [ABSTRACT FROM AUTHOR]

The purpose of these papers is to minimize the importance of technology, ignoring its basic role in constructing technical products can lead to a substantial increase in the workload and the consumption of material necessary for their manufacture and consequently to the increase in the costs for their manufacture. As regards the design activity, it is necessary to automate the main stages, which are: conceptual design, analysis and technological design. It is noteworthy that the analysis part is an integral part of the design process. Even if the analysis cannot fully replace the prototype experimental test, it can help the designer develop an optimized prototype. [ABSTRACT FROM AUTHOR]

The work presented is aimed at the investigation of the influence of beam-to-column connections on the seismic response of MR-Frames, with and without 'set-backs', designed according to the Theory of Plastic Mechanism Control. The investigated connection typologies are four partial strength connections whose structural details have been designed to obtain the same flexural resistance. The first three joints are designed by means of hierarchy criteria based on the component approach and are characterized by different location of the weakest joint component, leading to different values of joint rotational stiffness and plastic rotation supply and affecting the shape of the hysteresis loops governing the dissipative capacity. The last typology is a beam-to-column connection equipped with friction pads devoted to the dissipation of the earthquake input energy, thus preventing the connection damage. An appropriate modelling is needed to accurately represent both strength and deformation characteristics, especially with reference to partial-strength connections where the dissipation of the earthquake input energy occurs. To this aim, beam-to-column joints are modelled by means of rotational inelastic springs located at the ends of the beams whose moment-rotation curve is characterized by a cyclic behaviour which accounts for stiffness and strength degradation and pinching phenomena. The parameters characterizing the cyclic hysteretic behaviour have been calibrated on the base of experimental results aiming to the best fitting. Successively, the prediction of the structural response of MR-Frames, both regular frames and frames with set-backs, equipped with such connections has been carried out by means of both push-over and Incremental Dynamic Analyses. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

With the present paper, the author proposes a fitting method for approximating experimental data retrieved from any full-field technique. Unlike most of the fitting procedures, the method works on data distributed on a surface of any shape, and the mathematical model is able to take into account of both the 3D shape of the surface and of the experimental quantity to be fitted. The paper reports all the mathematical steps necessary for applying the method, which was tested on two sets of experimental data obtained by an out-of-plane speckle interferometer working in two different conditions of noise. Experimental results showed the capability of the method to work in presence of high level of noise. [ABSTRACT FROM AUTHOR]

Amino acid ionic liquids are green solvents with low toxicities and properties suitable for precombustion CO2 capture, such as high CO2 absorption, good thermal stability, and negligible vapor pressure. However, their high viscosities and relatively high costs have hampered their industrial applications. In this work, we systematically studied the amino acid ionic liquid tetrabutylphosphonium glycinate ([P4444][Gly]) and its blends with the low-cost and less viscous cosolvent poly(ethylene glycol) (PEG400). The concentration of the blend solvent was optimized with respect to CO2 solubility, regeneration efficiency, and cyclic capacity. The solubilities of CO2 in [P4444][Gly], PEG400, and their blends of four different concentrations were measured experimentally in the temperature range of 60-140 °C and up to a pressure of 17 bar. The results showed that the CO2 solubility increased with increasing ionic liquid concentration in the blend and decreased with increasing temperature. The optimum CO2 absorption was determined to occur at 30 wt % of [P4444][Gly] in the blend. The regeneration study of the 30 wt % [P4444][Gly]-70 wt % PEG400 blend for three cycles verified its reusability in the process and confirmed that the reaction between [P4444][Gly] and CO2 can be reversed at 140 °C. The CO2 absorption capacity of the blend absorbent was found to be up to a loading of 1.23 mol of CO2/mol of absorbent. The parameter fitting of the experimental data using empirical correlations was evaluated, and these correlations were developed in particular to predict the blend solvent of an amino acid ionic liquid-PEG400 system based on the ionic liquid concentration and temperature. [ABSTRACT FROM AUTHOR]

In the previous work, a machining robot based on an industrial robot was developed for foamed polystyrene materials. A robotic CAM system was incorporated in the robot to realize teachingless operation. In this paper, a fuzzy reasoning method processing radius of curvature is designed to skilfully regulate endmill's feed rate. The basic design of the machining robot using the fuzzy feed rate controller is presented for foamed polystyrene materials. Further, it is demonstrated that the mapping obtained by the fuzzy feed rate controller is well replaced by a multi-layered neural network. [ABSTRACT FROM AUTHOR]

Covariances are as important as variances when dealing with experimental data and they must be considered in fitting procedures and adjustments in order to preserve the statistical properties of the adjusted quantities. In this paper, we apply the Least Square Method in matrix form to several simple problems in order to evaluate the consequences of covariances in the fitting procedure. Among the examples, we demonstrate how a measurement of a physical quantity can change the adopted value of all other covariant quantities and how a new single point ( x , y ) improves the parameters of a previously adjusted straight-line. [ABSTRACT FROM AUTHOR]

We introduce a new method that approximates free-form surfaces by envelopes of one-parameter motions of surfaces of revolution. In the context of 5-axis computer numerically controlled (CNC) machining, we propose a flank machining methodology which is a preferable scallop-free scenario when the milling tool and the machined free-form surface meet tangentially along a smooth curve. We seek both an optimal shape of the milling tool as well as its optimal path in 3D space and propose an optimization based framework where these entities are the unknowns. We propose two initialization strategies where the first one requires a user’s intervention only by setting the initial position of the milling tool while the second one enables to prescribe a preferable tool-path. We present several examples showing that the proposed method recovers exact envelopes, including semi-envelopes and incomplete data, and for general free-form objects it detects envelope sub-patches. [ABSTRACT FROM AUTHOR]

The present investigation deals with an evaluation and comparison of Cv of CH soils using three methods: Casagrande logarithm of time fitting method, Taylor's square root of time fitting method and inflection point method. The soils considered in this study were collected from different places around Hyderabad, Andhra Pradesh, India, belonging to intrinsic class CH soils. Approximately, both Casagrande and Taylor's methods presented the same range of Cv values in comparison to the inflection point method. In addition, empirical relations for swell index (Cs) with compression index (Cc) and plasticity index (PI) with finer fractions were obtained. The relation between applied pressure and Cv values obtained from various methods was also derived. Finally, the study results revealed that Casagrande and Taylor's methods predict comparable values of Cv for CH soils and hence can be recommended in view of simplicity. [ABSTRACT FROM AUTHOR]

The quality of machined parts and tooling costs are major challenges encountered during the turning process. Therefore, optimum machining parameters suitable for turning operations must be selected in other to obtain the desired quality of the finished product at reduced machining time and cost. The present study was carried out on AISI 1018 low carbon steel during turning operation to reduce tooling costs as a result of tool wear and achieve optimum metal removal rate. Taguchi technique was employed using the L9 orthogonal array and the analysis of variance (ANOVA) to investigate the effect of the turning parameters on Metal Removal Rate (MRR) and Tool Wear Rate (TWR). The LARGER THE BETTER signal to noise (S/N) ratio based on the Taguchi technique was applied for MRR while the LOWER THE BETTER S/N ratio was applied for TWR. The results revealed that depth of cut is the most significant process parameter for MRR with a percentage contribution of 86.84%; the cutting speed and the feed rate are the most significant process parameters for TWR with percentage contributions of 60.86% and 33.03% respectively. The study concludes that AISI 1018 low carbon steel has a maximum MRR of 35.29mm³/s and a minimum TWR of 0.21mm/s. [ABSTRACT FROM AUTHOR]

A comparative study is presented for the latest bio-inspired optimization algorithms, known as bacterial foraging, firefly, cuckoo search, krill herd, and cuttlefish algorithms. This study also included the more established genetic and particle swarm optimization methods. These algorithms are then applied to a partial-fraction model fitting of tabulated measured dielectric function data for noble metals at optical wavelengths. [ABSTRACT FROM PUBLISHER]

Capability analysis corresponds to a set of methods used to estimate and test the ability of an in-control process to provide a specific output. When there is only one quality characteristic that behaves as a continuous random variable, indices like C and C can be used to measure how well requirements are met. Under normality, variation is indicated using 3− s i g m a limits; otherwise, the corresponding quantiles are used. Distribution fitting and transformations to normality can be used to estimate quantiles by finding an overall fit to the data available. However, by giving the same weight to all observations, the best possible fit of extreme values can be lost. To address this issue, a regression approach is proposed to fit functions over maximum likelihood estimates of probabilities of extreme values. A case study from the automotive industry is used to illustrate the proposed approach. To evaluate the performance, extensive Monte Carlo simulation is used, and the results are compared with the corresponding approach using the Clements method. The proposed nonparametric technique shows smaller MAD when high levels of skewness exist. Practitioners with basic knowledge of regression analysis may find the approach useful to estimate capability indices without the need of a specific probability distribution. [ABSTRACT FROM AUTHOR]

Curved mating surfaces that exist in complex engine parts such as turbine blades play a critical role in part fitting and assembly and, thus, system performance. Control of precise surface metrology (e.g., form error, surface roughness) during machining of such surfaces is highly challenging, especially when processing super alloys like hardened steels. This work aims to experimentally investigate surface metrology of a 12.70-mm-thick curved plate platform (with S-shaped sidewall) of AISI SS304 material during milling on a vertical three-axis milling machine with three different tool path strategies: ramp, contour, and peripheral. Experiments are performed to study surface location error (SLE) and roughness during upward and downward feeding of tool on both concave and convex sidewall surfaces at different spindle speed and feed combinations. SLE values that are estimated as undercut or overcut with respect to the desired surface are found to be minimum with ramp (15.05 μm), followed by contour (18.63 μm), and maximum with peripheral (24.12 μm) milling paths. However, peripheral milling may be preferable in terms of surface roughness (improved about 40 %) and overall machining time (six times faster than ramp milling). The findings are analyzed based on the associated cutting mechanics and cutting forces. [ABSTRACT FROM AUTHOR]

We present lzifu (LaZy-IFU), an idl toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. lzifu is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. lzifu has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of lzifu, demonstrating its accuracy and robustness. We also show examples of applying lzifu to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line profiles presented in IFS data. The code is made available to the astronomy community through github. lzifu will be further developed over time to other IFS instruments, and to provide even more accurate line and uncertainty estimates. [ABSTRACT FROM AUTHOR]

Objective: To provide a review of sustainable sizing practices that reduce waste, increase sales, and simultaneously produce safer, better fitting, accommodating products.Background: Sustainable sizing involves a set of methods good for both the environment (sustainable environment) and business (sustainable business). Sustainable sizing methods reduce (1) materials used, (2) the number of sizes or adjustments, and (3) the amount of product unsold or marked down for sale. This reduces waste and cost. The methods can also increase sales by fitting more people in the target market and produce happier, loyal customers with better fitting products. This is a mini-review of methods that result in more sustainable sizing practices. It also reviews and contrasts current statistical and modeling practices that lead to poor fit and sizing. Fit-mapping and the use of cases are two excellent methods suited for creating sustainable sizing, when real people (vs. virtual people) are used. These methods are described and reviewed. Evidence presented supports the view that virtual fitting with simulated people and products is not yet effective.Conclusions: Fit-mapping and cases with real people and actual products result in good design and products that are fit for person, fit for purpose, with good accommodation and comfortable, optimized sizing. While virtual models have been shown to be ineffective for predicting or representing fit, there is an opportunity to improve them by adding fit-mapping data to the models. This will require saving fit data, product data, anthropometry, and demographics in a standardized manner. For this success to extend to the wider design community, the development of a standardized method of data collection for fit-mapping with a globally shared fit-map database is needed. It will enable the world community to build knowledge of fit and accommodation and generate effective virtual fitting for the future.Application: A standardized method of data collection that tests products' fit methodically and quantitatively will increase our predictive power to determine fit and accommodation, thereby facilitating improved, effective design. These methods apply to all products people wear, use, or occupy. [ABSTRACT FROM AUTHOR]

This paper presents a computer-based technique to construct B-spline parametric models from a large set of airfoil data points, with a reduced number of parameters involved in the geometric representation of the airfoil profile. The proposed method uses different techniques related with the B-spline properties adapted to the geometry of an airfoil (a thin section with great changes of curvature) and produces a B-spline curve that is close to the data points maintaining a maximum tolerance distance. This curve can be used for calculations and is expected to provide a good framework for aerodynamic or hydrodynamic optimization, based on its reduced number of geometric parameters and on its calculation time, when compared with other methodologies. The method stresses the fitting of the airfoil's leading edge, which has a significant impact on the properties of the airfoil. B-spline curves and surfaces are used in this method because they are widely used in CAD-CAM software products and can be easily exported to other programs. [ABSTRACT FROM AUTHOR]

Fixtures are the work-holding devices, widely used in manufacturing, to completely immobilize the workpiece during machining. The position of fixture elements around the workpiece strongly influences the workpiece deformation which in-turn affects the machining accuracy. The workpiece deformation can be minimized by finding the appropriate position for the locators and clamps. Thus, it is necessary to model the complex behavioral relationship that exists in the fixture–workpiece system. In this research paper, response surface methodology is used to model the relationship between position of locators and clamps and maximum deformation of the workpiece during end-milling, and then the developed model has been optimized by genetic algorithm and particle swarm optimization. As the predictive model is being developed by response surface methodology, a huge reduction in computational complexity and time is achieved during the optimization of machining fixture layout. Also, it is evident that the approach which integrates response surface methodology and particle swam optimization produces better results. [ABSTRACT FROM AUTHOR]

A specific technical expertise is required to machine metal–matrix composites (MMCs). It is well known, from the literature data, that MMCs cutting involves high costs and high machining times due to excessive tool wear and possible subsurface damage. In recent years, the emphasis of research has focused on understanding the mechanics and mechanisms that are responsible for the behaviour of MMCs during the material removal process. These kinds of studies would be the most effective way of understanding the machining characteristics and deformation behaviour of the material. This work is a contribution to understanding the effects of two antagonistic phenomena that determine MMCs behaviour during the cutting process, such as the thermal softening of the matrix and the matrix hardening due to strain. To this end, a simplified model that describes the behaviour of the reinforcements beneath the machined surface is proposed and experimentally validated. [ABSTRACT FROM AUTHOR]

In order to improve fitting accuracy of grey forecasting model according to the function transformation theory and grey system modeling theory, DGM(1,1) model based on anti-cotangent function for a non-negative ascending sequence is built in this paper. And DGM(1,1) model based on variable speed translation anti-cotangent function transformation for a non-negative oscillating sequence is built in this paper. For a non-negative ascending sequence, it has been proved that the smooth ratio, stepwise ratio deviation, and stepwise ratio variance after the function transformation can be reduced effectively. The function transformation methods in this paper are used in setting up models for ascending and oscillating sequences and the calculation results of actual examples show that the function transformation proposed in this paper is valid to an extent. [ABSTRACT FROM AUTHOR]

Results are given for an experimental study of steel manufacturing technology satisfying specifications for strength class not less than K60 for connecting pieces (fittings). Laboratory melts, rolling, and heat treatment by different regimes are performed for low-alloy steels of four composition versions containing 0.05-0.08% carbon. Steels containing about 1% copper, in contrast to steels with a lower content or without addition of copper after normalizing and tempering, demonstrate a level of properties corresponding to strength class K60. Research shows that additional strengthening occurs as a result of precipitation of fine particles enriched in copper after tempering. Steel impact strength KCV and relative elongation of steels alloyed with copper are at a high level due to a low carbon content and addition of nickel, and also prior grain refinement during controlled rolling. During tempering after normalizing, a more balanced set of properties is provided with tempering at 600°C. The steel developed may be used for preparing fittings of strength class K60 by hot stamping without thermal improvement or of strength class K65 after additional quenching and tempering. [ABSTRACT FROM AUTHOR]

The objective of this study is to examine the variations in hair mineral concentrations measured by particle induced X-ray emission (PIXE). As the concentrations reflect the historical profile of minerals in blood for a few days to several years, hair mineral measurements vary among the hair strands of a sample as well as the locations on hair strands where PIXE beams are irradiated. PIXE analysis presents not only mineral measurements but also standard errors associated with them due to uncertainty in fitting analysis of X-ray spectrum. We developed statistical methods to decompose the intra-individual variance into the variances due to locations and that due to the fitting analysis. This study describes the results of statistical analysis on the variations in six minerals (Cu, Fe, Sr, Ca, Cl and Pb) and compares the results for better understanding of variations in hair mineral measurements obtained from hair analysis using PIXE. [ABSTRACT FROM AUTHOR]