Experimental Run Research Articles

Design of experiment (D.O.E) by Taguchi model for optimization of different process parameters for LSPR system to detect VCO adulteration

Virgin coconut oil (VCO) being one of the costly oils is prone to be adulterated with cheaper oils viz., coconut oil (CO). Attempt were made to develop a new innovative way to detect the adulteration in VCO using Localized surface plasmon resonance (LSPR) system. Optimization of certain process parameters is an prioritize criteria for detection by LSPR system for further development of the calibration curve. The traditional method for optimization involved the study of one variable at a time, which in turn required a large number of experimental runs. The Design of experiments (D.O.E) by Taguchi design employed here for optimization of LSPR system to achieve maximum reliability with a minimum experimental run. The process parameters viz., flowrate, surfactant and pH were selected for the optimization of the LSPR system to detect the VCO adulteration with CO in PBS buffer. For obtaining a maximum response a large signal to noise ratio was applied. An optimal condition for LSPR system was obtained at a Flowrate (200µl/min), pH (7.0) and surfactant (Tween 20) with a significant difference (p

Style of Fractional Crystallization in Basalts from the Paleoarchean Western Iron Ore Group of Singhbhum Craton, Eastern India: Implications from One Atmosphere Experimental Studies

Abstract One atmosphere experimental study on fresh basaltic rocks of Paleoarchean western Iron Ore Group (IOG) basin of Singhbhum Craton, Eastern India gives insight of the crystallization behavior of the parent magma, liquid lines of descent and appearance of the different constituent phases. The natural starting material is sufficiently ferroan (FeOt: 14.28 wt%) and corresponds to ‘ferro-basalt’. Regarding the experimental run products, clinopyroxene shows Al2O3 rich character (ranging from 2.23 – 6.94 wt%; formed due to fluctuating silica activities in the magma) while plagioclase reveals typical Fe-Mg enrichment (that corresponds to higher KdFe-Mg between plagioclase and the parent liquid caused due to immiscible silicate melt inclusion in plagioclase where Mg enters more readily in plagioclase than Fe). The run-product glass corresponds to both high and low iron contents suggesting liquid immiscibility in the parent magma at particular temperature-domains. This study suggests that the crystallization of the western Iron Ore Group basalts represents a broad ‘Skaergaard analogue’ involving depression/shift of eutectic point in the diopside-anorthite system during crystallization.

Characterization of reflected shock tunnel air conditions using a simple method

A new method to characterize air test conditions in hypersonic impulse facilities is introduced. It is a hybrid experimental–computational rebuilding method that uses the Fay–Riddell correlation with corrections based on thermochemical nonequilibrium computational fluid dynamic results. Its benefits include simplicity and time-resolution, and using this method, a unique characterization can be made for each individual experimental run. Simplicity is achieved by avoiding the use of any optical techniques and overly expensive numerical computations while still maintaining accuracy. Without making any assumptions to relate the reservoir conditions to the nozzle exit conditions, the work done characterizing four test conditions in a reflected shock tunnel is presented. In this type of facility, shock compression is used to produce an appropriate reservoir, which is then expanded through a nozzle to produce hypersonic flow. Particular focus is given to the nozzle exit total enthalpy where a comparison is made with the reservoir enthalpy obtained using the measured shock speed and pressure in the shock tube. Good agreement is observed in all cases providing validation of the new approach. Additionally, static pressure measurements showed clearly that conditions III and IV have a thermochemical state which likely froze shortly after the nozzle throat. Also, the nozzle flow is shown to be almost isentropic. Due to the simplicity of the current method, it can be easily implemented in existing facilities to provide an additional independent estimate alongside existing results.

Multi response optimization of machining parameters for an annealed Monel K 500 alloy in drilling using Machine learning techniques and ANN

Manufacturing companies are focusing on continuous process development to thrive in today’s quality-conscious market. It is particularly relevant to investigate machining processes for advanced materials such as superalloys. Drilling is a major operation that is used in the majority of manufacturing processes. Hence, this research work is focused on investigating the drilling performance of the Monel K500. The output responses under consideration are metal removal rate (MRR), surface roughness, and tool wear. Various contemporary techniques were utilized in this work, namely machine learning methods, artificial neural networks, principal component analysis, and grey relation analysis using uncoated, coated, and HSS (high-speed steel) drills. After annealing, the softened material can be easily machined to increase the MRR and decrease tool wear and surface roughness. The experimental results show that, after annealing, the surface roughness values for HSS drills have been reduced by 23.86%, uncoated drills by 27.29%, and coated drills by 29.27%, respectively. Moreover, tool wear values for HSS drills decreased by 28.51%, uncoated drills by 34.7%, and coated drills by 33.71%, based on the relative error approach. MRR values for HSS drills increased by 20.51 %, uncoated drills by 23.08%, and coated drills by 23.5%, respectively. For PCA (principal component analysis), feed (47%), and for GRA (gray relation analysis), feed (40.1%) will be the significant parameter followed by speed, and both methods have identified the same experimental run values for optimization of cutting parameters. The theoretical values were predicted using machine learning methods, which utilized the Python language using the Google Colab and then validated with experimental values. The predicted values obtained by the decision tree are close to the measured values as compared to support vector regression and K-nearest neighbor based on relative error. The estimated values obtained by the ANN (artificial neural networks) approach, using Easy NN plus software, match well with the actual values, with a slight deviation.

WEDM of Al/SiC/Ti composite: A hybrid approach of RSM-ARAS-TLBO algorithm

Aluminum-based hybrid composites are the lightweight materials used for many industrial applications. These applications include brake parts, automotive engine, high speed rotating shafts, high speed machinery and robots. The machining of aluminum was normally done by conventional machining processes. However, after the addition of ceramic particles, it became difficult to process the hybrid composite by conventional processes. Thus, non-conventional machining processes are used for the machining of aluminum-based hybrid composite. In the present work, the aluminum-based hybrid composite was developed using stir casting method, where Al6063 was used as matrix material and SiC along with Ti were used as reinforcement material. After the development of hybrid composite, the material is processed on wire electric discharge machining (WEDM). The varying control factors while machining was pulse on-time (Ton), pulse off-time (Toff), servo voltage (SV) and wire feed (WF). However, the response variable to measure the machining characteristics were cutting speed (CS) and kerf width (KW). The experiments were planned according to Response Surface Methodology (RSM) based Box Behnken Design (BBD). The response variables were converted into optimality function using Additive Ratio Assessment (ARAS) and then the developed empirical model was solved by Teaching Learning Based Optimization (TLBO). The optimized setting suggested by hybrid approach is Ton: 128 μs; Toff: 48 μs; SV: 48 V; WF: 7 m/min. After the optimization an improvement of 12% in optimality function, 18.24% in CS and 17.11% in KW was observed as compared to the best experimental run. The morphological investigation shows that at the optimized setting the presence of micro-cracks, sub-surface, globules and recast layer reduced significantly.

The Curcumin Supplementation with Piperine Can Influence the Acute Elevation of Exercise-Induced Cytokines: Double-Blind Crossover Study.

Simple SummaryInflammation is an immune response to harmful stimuli, such as pathogens and damaged cells. Intense exercise can induce a local and systemic inflammatory response as well. We believe that exercise-induced inflammatory responses are essential for muscle repair and regeneration. However, uncontrolled acute inflammation in athletes during the training process and competition could reduce the level of performance. In this study, we investigate the effects of curcumin and piperine on the exercise-induced inflammatory response.Background: to evaluate the effects of one week of supplementation with curcumin combined with piperine on physical performance, immune system cell counts, muscle damage, and plasma levels of inflammatory markers after a treadmill running training session. Methods: This study is a double-blind, crossover-balanced clinical trial with a three-week intervention. Sixteen male runners with a mean age of 36 ± 9 years and VO2 max of 60.6 ± 9.03 mL.kg −1 min −1 were recruited and randomly divided into 2 groups: the first group (CPG) was supplemented daily for 7 days with 500 mg of curcumin + 20 mg piperine, and the second group (PG) was supplemented with 540 mg of cellulose. After the 7th day of supplementation, the volunteers participated in the experimental running protocol, where blood samples were collected before, after, and one hour after exercise for analysis of the number of leukocytes, creatine kinase, and cytokine concentration (IL-2, TNF-α, IFN, IL-6, and IL-10) using flow cytometry. This process was repeated, reversing the supplementation offered to the groups. Results: curcumin and piperine supplementation could not change the physical performance, immune cell counts, and muscle damage; however, the aerobic fatiguing exercise protocol inhibited the elevation of the plasmatic levels of some cytokines. The running exercise protocol could elevate the circulating levels of IL-2 (from 49.7 to 59.3 pg/mL), TNF-α (from 48.5 to 51.5 pg/mL), INF (from 128.8 to 165.0 pg/mL), IL-6 (from 63.1 to 77.3 pg/mL), and IL-10 (from 48.9 to 59.6 pg/mL) 1 h after the end of the running protocol. However, the curcumin and piperine supplementation could inhibit this elevation. Conclusions: curcumin and piperine supplementation had no effect on physical performance, immune cell counts, or muscle damage; however, the supplementation could modulate the kinetics of IL-2, TNF-α, INF, IL-6, and IL-10 1 h after the end of exercise.

Imaging of particle deposition and resulting flow field during flocculation filtration within a granulated activated carbon filter

Flocculation filtration onto granulated activated carbon (GAC) filters is an advanced treatment method to achieve lower phosphorous and micropollutant discharge in wastewater treatment plants. However, the suitability is put into question as the deposition of suspended solids (SS) onto a GAC filter is aligned with more frequent backwashing ongoing with abrasion of GAC and downtimes. To evaluate the filtration process of SS onto GAC filters on the pore scale, we resolved the particle deposition in a timely and spatially resolved image series by means of magnetic resonance imaging (MRI). Besides structural images, flow measurements were acquired to evaluate the impact of SS accumulation onto the local flow field. The column had an inner surface area of 1.54 cm2 and was filled with GAC up to 10 cm in height. In total, 6.4 L of wastewater originating from a secondary clarifier were added to the GAC filter in steps of 0.2 L. The wastewater contained approximately 8.4 mg/L TSS after flocculation and precipitation. Results of one experimental run are presented. Particle accumulations within the GAC filter as well as a formation of a deposit layer was found. During the filtration process preferential inflow points into the GAC filter were recognizable. The transition of a preferential inflow point to another was often aligned with the redistribution of upper parts of the GAC filter and a compaction of accumulated SS. Analysis of flow distributions revealed that the equivalent filter velocity of 28.8 m/h is 2.3 times higher compared to the average filter velocity (12.5 m/h including porosity). Further, the equivalent filter velocity increased up to 100.8 m/h at the end of the experiment. As particles do not distribute equally over the filter height, those velocities are not representative for the whole height of GAC filters. The current study provides insights into a real flocculation filtration process without using artificial materials for imaging purposes.

The Effectiveness of Discovery Learning Method on Reading Descriptive Text at Eighth Grade of SMP Diniyah Al Falahiyah Lamongan

This researcher measures the effectiveness of discovery learning on reading descriptive text at eight grades of SMP Diniyah Al Falahiyah Lamongan in academic 2020/202. The discovery learning method strategy works for the students' mental, easy to interact (actively) and new information independently. The method of the research utilized a quantitative experimental method by using a pre-experimental design. Conducted the sample of the study was at VII-A class with 30 students. The instrument of collecting data used try-out and test (pre-test and post-test). The test had utilized to know students' abilities before and after the experiment run. The result of the research showed the mean score in the pre-test was 57.33, and the post-test was 74.50. The result was that the post-test was higher than the pre-test. The analysis using the SPSS based paired sample t-test formula produces a significance value of sig. (2-tailed) had 0.000 at the critical value for the 5% level (0.000 < 0.05). The obtained t-test had -21.908, and the t-table was 2.042. So, the test score was higher than the t-table (-21.908 > 2.042). It means rejected Ho and Ha is accepted. It can conclude that the discovery learning method has significant and effectiveness to reading descriptive text.

Vertical Wind Tunnel Experiments and a Theoretical Study on the Microphysics of Melting Low-Density Graupel

Abstract Vertical wind tunnel experiments were carried out to investigate the melting of low-density lump graupel while floating at their terminal velocities. The graupel characteristics such as maximum dimension, density, and axis ratio were 0.39 ± 0.06 cm, 0.41 ± 0.07 g cm−3, and 0.89 ± 0.06. The airstream of the wind tunnel was gradually heated simulating lapse rates between 4.5 and 3.21 K km−1. Each experimental run was performed at a constant relative humidity that was varied between 12% and 92% from one experiment to the other. From the image processing of video recordings, variations in minimum and maximum dimension, volume, aspect ratio, density, volume equivalent radius, and ice core radius were obtained. New parameterizations of the terminal velocity prior to melting and during melting were developed. It was found that mass and heat transfer in the dry stage is 2 times as high as that of liquid drops at the same Reynolds number. Based on the experimental results, a model was developed from which the external and internal convective enhancement factors during melting due to surface irregularities and internal motions inside the meltwater were derived using a Monte Carlo approach. The modeled total melting times and distances deviated by 10% from the experimental results. Sensitivity tests with the developed model revealed strong dependencies of the melting process on relative humidity, lapse rate, initial graupel density, and graupel size. In dependence on these parameters, the total melting distance varied between 600 and 1200 m for typical conditions of a falling graupel. Significance Statement The accuracy of weather forecast models to predict precipitation depends strongly on the representation of cloud processes in those models. Heavy rain events are mostly the result of melting ice particles. Furthermore, melting affects the storm characteristics and its destructive potential. In this study, we investigated the melting of low-density graupel, which constitute an important class of precipitation particles. Our experiments in a vertical wind tunnel under close to atmospheric conditions indicated an increased melting rate of graupel due to surface irregularities. We provided experimentally derived coefficients that supplement present theoretical concepts describing melting in forecast models. In this way, our study contributes to the improvement of current weather forecasts.

Robustness of sequential third-order response surface design to missing observations

Response surface designs are generally used in process/product optimization studies. Sequential third-order response surface designs are advantageous when the experimenter encounters the significance of lack of fit of a fitted second-order model while establishing the relationship between the input and response variables. In some experimental situations, responses pertaining to certain design points may be destroyed or unobtainable or inaccessible. The unavailability of the observations pertaining to certain experimental run(s) affects the design property and affects the analysis of variance. In this paper, we have examined the robustness of sequential third-order rotatable design and investigated the loss of information when one or two observations pertaining to experimental run(s) is (are) missing, which are at different radii from the design centre. It has been found that the maximum loss of information occurs when the observation at the design points which are at higher radii from the design centre is lost and the design has the minimum efficiency.

An Integrative Simulation for Mixing Different Polycarbonate Grades with the Same Color: Experimental Analysis and Evaluations

The processing parameters’ impact such as temperature (Temp.), feed rate (F.R.), and speed (S.) at three distinct grades of the same color was explored in this study. To investigate the effect of the characteristics on color formulations, they were each adjusted to five different levels. For these grades, which were all associated with the same color, an intermeshing twin-screw extruder (TSE) was used. The compounded materials were molded into flat coupons then evaluated with a spectrophotometer for their CIE (L*, a*, b*, and dE*) values. A spectrophotometer was used to determine the color of a compounded plastic batch, which measured three numbers indicating the tristimulus values (CIE L*a*b*). The lightness axis, which ranged from 0 (black) to 100 (white), is known as the L*-axis (white). Redness-greenness and yellowness-blueness were represented by the other two coordinates, a* and b*, respectively. The color difference deviation (Delta E*) from a target was dimensionless, when dE* approached zero. However, the most excellent favorable color difference value occurred and different processing impact factors on polycarbonate grade were investigated. Using the response service design (RSD) software of Stat-Ease Design-Expert® (Minneapolis, MN, USA), historical data were gathered and evaluated. To reduce the value of dE*, the impacts of these processing factors were investigated with the three processing parameters. The whole tristimulus color value could be simulated. Parameters were adjusted on 45 different treatments, using a five-level controlled response method to investigate their impact on color and detect non-optimal responses. The ANOVA for each grade was used to build the predicted regression models. The significant processing parameters were subjected to experimental running to simulate the regression models and achieve the best color, reducing waste.

Radiative Cooling, Latent Heating, and Cloud Ice in the Tropical Upper Troposphere

Abstract The radiative cooling rate in the tropical upper troposphere is expected to increase as climate warms. Since the tropics are approximately in radiative–convective equilibrium (RCE), this implies an increase in the convective heating rate, which is the sum of the latent heating rate and the eddy heat flux convergence. We examine the impact of these changes on the vertical profile of cloud ice amount in cloud-resolving simulations of RCE. Three simulations are conducted: a control run, a warming run, and an experimental run in which there is no warming but a temperature forcing is imposed to mimic the warming-induced increase in radiative cooling. Surface warming causes a reduction in cloud fraction at all upper-tropospheric temperature levels but an increase in the ice mixing ratio within deep convective cores. The experimental run has more cloud ice than the warming run at fixed temperature despite the fact that their latent heating rates are equal, which suggests that the efficiency of latent heating by cloud ice increases with warming. An analytic expression relating the ice-related latent heating rate to a number of other factors is derived and used to understand the model results. This reveals that the increase in latent heating efficiency is driven mostly by 1) the migration of isotherms to lower pressure and 2) a slight warming of the top of the convective layer. These physically robust changes act to reduce the residence time of ice at any particular temperature level, which tempers the response of the mean cloud ice profile to warming. Significance Statement Here we examine how the amount of condensed ice in part of the atmosphere—the tropical upper troposphere (UT)—responds to global warming. In the UT, the energy released during ice formation is balanced by the emission of radiation to space. This emission will strengthen with warming, suggesting that there will also be more ice. Using a model of the tropical atmosphere, we find that the increase in ice amount is mitigated by a reduction in the amount of time ice spends in the UT. This could have important implications for the cloud response to global warming, and future work should focus on how these changes are manifested across the distribution of convective cloud types.

Enhancing the Surface Finish of Product Coming From High Precision CNC- Milling Center by Varaying the Machtine Parameters Through Taguchi Approach

Abstract: The manufacturing process for products with high degree of precision is very critical and hence increasing the surface quality, wherever possible has been the prime motive, so many leading companies are working with high precision CNC-VMC series for operations such as Drilling, Tapping, Turning, Milling, etc. Surface roughness is the most important indicator of surface quality in machined items. So as to achieve that changing machine parameters as per product size and environment is necessary. In this research, the parameters which are taken into account are : spindle speed, feed rate, and depth of cut. Taguchi Design is utilized in this study to find the best combination of parameters to reach out to the maximum surface finish criteria. For various combinations of three parameters: spindle speed, feed rate, and depth of cut, experiments are carried out using the Taguchi orthogonal array. The surface roughness Ra is analyzed for each experiment run using Taguchi. Keywords: Taguchi Method, Spindle Speed, Feed rate, Surface finish, Surface roughness, Depth of cut.

A comparative study of NaOH and KOH electrolytes in micro-ECM

ABSTRACT Tungsten microtool electrode is one of the preferred tool electrodes in micro electrochemical machining (µECM) of hard to machine materials. During the pilot experiments with different types of electrolytes materials (such as NaOH, HNO3, NaBr, KOH, H2SO4, NaCl, NaNO3 and HCl), it has been found that KOH(Aq.) and NaOH(Aq.) electrolytes are suitable for the fabrication of tungsten microtools through µECM process. Therefore in this research, a comparative study between NaOH(Aq.) and KOH(Aq.) electrolytes have been carried out in the fabrication of tungsten microtools through µECM. DC voltage (V), electrolyte concentration (Mol/L) and machining time (Minutes) are chosen as machining parameters in order to investigate their role on response outputs i.e. tool radius reduction (Δ) and material removal rate (MRR). Roles of machining parameters on the response output are analysed through Taguchi design technique and ANOVA is employed to determine the dominant machining parameters on the response outputs. Experimental results indicate ‘Δ’ and ‘MRR’ obtained with NaOH(Aq.) is greater than ‘Δ’ and ‘MRR’ obtained with KOH(Aq.) respectively at most of the experimental run. But microscopic view of the fabricated microtools indicate that the surface uniformity throughout the length of the microtools obtained with KOH(Aq.) electrolyte is favourable than NaOH(Aq.).

Empirical and experimental constraints on Fe-Ti oxide-melt titanium isotope fractionation factors

The Titanium (Ti) isotope compositions of felsic rocks are heavier than their mafic counterparts, and alkaline magmas develop heavier Ti isotope compositions compared to other magma series during magmatic differentiation. Both observations are interpreted to reflect the preferential sequestration of light Ti isotopes in Fe-Ti oxides, such as rutile, ilmenite and titanomagnetite. However, such interpretations so far rely on whole rock studies of cogenetic magmatic samples and the detailed mechanics of oxide-melt equilibrium on the Ti isotope composition of magmas is poorly constrained. To address this, we have measured the Ti isotope composition of co-existing Fe-Ti oxides and groundmass or silicate melt in both natural lavas from contrasting tectonic settings (Heard Island and Santorini), and experimental run products (rutile-melt). All Fe-Ti oxide phases are consistently isotopically lighter than their respective host groundmass or silicate melt, with the magnitude of Δ49/47Tioxide-melt increasing from rutile to ilmenite, and titanomagnetite. The observed difference in Ti isotope fractionation between rutile-melt experiments and ilmenite-groundmass pairs is primarily reflective of small differences in their TiO bond length, with ilmenite being isotopically lighter (Δ49/47Tiilmenite-melt extrapolated to 1000 K = −0.600 ± 0.035‰) compared to rutile (Δ49/47Tirutile-melt at extrapolated to 1000 K = −0.404 ± 0.099‰) due to slightly longer TiO bonds in ilmenite. In contrast, the variation in Δ49/47Ti observed between titanomagnetite-groundmass pairs increases as a function of increasing TiO2 content (increasing ulvöspinel component) in titanomagnetite, with Δ49/47Tititanomagnetite-melt values extrapolated to 1000 K ranging from −0.811 to −1.451‰ in Ti-rich titanomagnetite (21–23 wt.% TiO2; Usp66-73) from Heard Island compared to −0.673‰ to −0.863 in Santorini (14–15 wt.% TiO2; Usp45-49). We interpret this to result from a weaker and distorted crystal lattice due to changes in the local cationic environment resulting from exchange of smaller Fe3+ ions with larger Fe2+ ions during magnetite-ulvöspinel solid solution. Our results are consistent with fractionation factors inferred from Ti isotopic analyses of mineral separates and ab-initio calculations. We use these fractionation factors in combination with Ti isotope fractionation factors for silicate minerals recalculated from previous studies, along with petrologic information to model the behaviour of Ti isotopes during partial melting of Earth’s mantle as well as reproducing the observed variation in δ49/47Ti of differentiated magmas from distinct geodynamic settings.

Tilt Angle’s Effects on Free Convection Heat Transfer Coefficient inside a Water-Filled Rectangular Parallelepiped Enclosure

The effect of tilt angle on free convection heat transfer is investigated experimentally inside a rectangular parallelepiped cavity filled with water. The cavity had the dimensions S × S × H (m3), where S was the inside length, and H was the inside height of the cavity. The lower surface was subject to constant heat flux, and the upper surface was cooled by a stream of ambient air. The free convection heat transfer data were generated using different uniform heat fluxes. Four tilt angles were considered: 0°, 30°, 60°, and 90°. The surface temperature measurements were collected 10 h after the experimental run to ensure that a steady-state was reached. It was noticeable that the free convection heat transfer strongly depended on the tilt angle and the modified Rayleigh numbers. The 3D results showed that the Nusselt number reached a maximum at 60° at a fixed modified Rayleigh number. An enhancement in the Nusselt number at any tilt angle was observed over that of a zero tilt angle, and the percent of enhancement was 7.92–62.38%, depending on the modified Rayleigh numbers and the tilt angle. It was also observed that as the modified Rayleigh number increased, the temperature uniformity on both the hot and cold surfaces was disturbed. Furthermore, an empirical correlation between the modified Rayleigh numbers and Nusselt numbers was obtained for each angle. Moreover, two overall general correlations are obtained to cover the four tilt angles (i.e., 0°, 30°, 60°, and 90°) and the modified Rayleigh numbers, which should be helpful for engineering applications.

Relative effect of wear parameters on the wear behavior of TiAlN coated tool steel and parametric optimization using MCDM method

ABSTRACT This study focuses on the relative effect of wear parameters and their optimisation for wear responses of TiAlN coating deposited on MDC-K tool steel using cathodic arc deposition technique. Taguchi L27 design of experiment was employed to design the experimental run with three wear parameters, namely, applied load (N), sliding velocity (Sv) and sliding distance (Sd). The dry sliding wear test was performed against the tungsten carbide (WC) counterbody to evaluate the wear behaviour of TiAlN coating. The wear behaviour evaluation was conducted based on the responses such as surface roughness, friction coefficient, wear mass loss, wear depth and worn surface hardness. The worn surface morphology reveals that micro-grooves and micro-ploughing were dominant wear mechanism at lower applied load, whereas coating delamination was evident at higher load values. ANOVA results show that the applied load was the most influential parameter with >63.27% contribution compared to other parameters. Finally, multi-criteria decision-making approaches were employed to optimise the wear parameter. The obtained result suggests the parameter combination of L= 10 N, Sv = 0.2 m/s and Sd = 1500 m to be the best alternative with the optimal value of the wear responses.

Sp-hybridized carbon atoms formed by low-energy collisions in carbon nanofoams produced by pulsed laser deposition

The appearance of an sp-hybridization signal has previously been reported in Surface-Enhanced Raman spectra of carbon nanofoams prepared by pulsed laser deposition (PLD). The details of the mechanism for the formation of the sp-hybridized carbon atoms need still further clarification. For a better understanding we have studied two samples produced by PLD in the same experimental run by placing one substrate in front of the plasma plume and a second one beside the graphite target. In this configuration the gas pressure is the same at both sites but the collision energies between the formed nanoparticles are very different. Our present results from Surface Enhanced Raman Spectroscopy and High-Resolution Transmission Electron Microscopy lead us to propose that the sp signal comes mostly from short carbon atom chains formed between carbon nanoparticles due to relatively low-energy collisions at deposition.

A Population Balance Methodology Incorporating Semi-Mechanistic Residence Time Metrics for Twin Screw Granulation

This work is concerned with the incorporation of semi-mechanistic residence time metrics into population balance equations for twin screw granulation processes to predict key properties. From the historical residence time and particle size data sourced, process parameters and equipment configuration information were fed into the system of equations where the input flow rates and model compartmentalization varied upon the parameters. Semi-mechanistic relations for the residence time metrics were employed to predict the particle velocities and dispersion coefficients in the axial flow direction of the twin screw granulation. The developed model was then calibrated for several experimental run points in each data-set. The predictions were evaluated quantitatively through the parity plots. The root mean square error (RMSE) was used as a metric to compare the degree of goodness of fit for different data-sets using the developed semi-mechanistic relations. In summary, this paper presents a more mechanistic but simplified approach of feeding residence time metrics into the population balance equations for twin screw granulation processes.

Multi-Objective Parametric Optimization of Weld Strength of Metal Inert Gas (MIG) Welding by using Analysis of Variance, Taguchi, and VIKOR Techniques

Abstract: Welding is an enormously essential manufacturing technique which allows the users to create permanent joints efficiently, due to its durability this process is extensively used in various industries like automotive, construction as well as in the aviation industry. The present study focuses on the optimization of the Metal Arc Welding using VIKOR method. Four input variables Current, Voltage, Wire Feed Rate and Gas Flow Rate are considered to study their effect on three responses tensile, bending and hardness on the weldments of AISI 1008 low carbon steel material. Experiments were planned as per Taguchi‘s L9 OA. As traditional Taguchi method is not adequate to solve multi responses problem, to overcome this limitation MCDM approach VIKOR analysis has been carried out for obtaining optimal parameters setting for multi-response optimization. Three specimens (for tensile, bending, and hardness) for each experimental run are fabricated for the measurement of respective strength and hardness. Investigation is done by following the steps of VIKOR method, and optimal parameter setting for multi quality response is obtained corresponding to the lower VIKOR index value. Keywords: Metal Inert Gas (MIG) Welding, VIKOR, S/N ratio, ANOVA