Wear Mechanisms in Thermally-Sprayed Mo-Based Coatings

The successful development of advanced diesel engines relies heavily on piston ring coating materials which can withstand elevated temperatures and reduce friction. Traditional hard chrome plating and flame-sprayed Mo-wire materials have reached their potential in the diesel engine environment, and alternatives are needed. Thermally-sprayed Mo-based allays and composites are being evaluated for applications as next-generation ring-face coatings. The alloy development task of producing complex Mo-based alloy powders for use as thermally-sprayed coating materials requires an understanding of their wear resistance under contact stress conditions. In this paper, the wear behavior of Mo and Mo+NiCrBSi thermally sprayed coatings is examined by pin-on-disc and single-point scratch-test methods. Microstructural analysis beneath worn regions have revealed that fracture of splats and their decohesion constitute the mode of failure. Improved wear resistance and stability of low friction coefficient was obtained by prealloying Mo with NiCrBSi prior to thermal spraying.     

Adaptive production control system for a flexible manufacturing cell using support vector machine-based approach

Real-time adaptive production control in the flexible manufacturing cell (FMC) is a complex issue that needs to be addressed to realize good performance and high productivity. In this paper, we have considered a support vector machine (SVM)-based simulation approach to resolve a production control problem in an FMC that operates in a dynamic environment. A SVM-based simulation approach chooses the most relevant scheduling rule out of several predefined ones on the basis of the current states of the system. This paper examines and compares the performance of the SVM-based simulation approach with the competent scheduling rules under two different operational environments which are characterized by the uncertainty of demand. We have also developed a Visual Basic-based simulation approach for scheduling of component parts in the context of FMC under different situations. The SVM methodology to control the production offers better performance than the single-rule-based production control system.     

Nanoenergetic Composite of Mesoporous Iron Oxide and Aluminum Nanoparticles

Ordered mesoporous Fe₂O₃ was synthesized using cetyltrimethylammonium chloride (CTAC) and polyethylene glycol octadecyl ether (Brij 76) surfactant templates. The gel time was monitored as a function of the concentration ratio of precursor to the surfactant. As-prepared FeOOH gels were extracted in ethanol to remove the surfactant and calcined at 200–400°C for 6 h so that α-Fe₂O₃ is produced. The FTIR spectra of these gels reveal complete removal of surfactant and water impurities and the presence of Fe-O vibrations. TEM images show ordering of mesopores in the gels prepared using surfactant templating and no ordering of the pores in the gels prepared without surfactant. The gels after calcinations were mixed with aluminum nanoparticles to prepare nanoenergetic composites. The burn rate of the nanocomposites containing ordered mesoporous Fe₂O₃ mixed with Al nanoparticles was compared with the one containing Fe₂O₃ with no ordering of mesopores and Al nanoparticles.     

An investigation of the effectiveness of fixture layout optimization methods

Deriving the optimal layout of fixture elements is critical to minimizing the impact of fixture–workpiece deformation on machined feature error. Various optimization methods for solving this problem have been reported. Unfortunately no investigation has been executed to compare their relative performance. This paper presents the methodology and results of an extensive investigation into the relative effectiveness of the main elements of these competing methods. All methods were tested over a broad range of conditions. Performance measures that were tracked included solution quality, solution repeatability, and computation time. The results of this investigation show that the best overall performance is provided by optimization methods that use both the genetic algorithm and continuous interpolation for the distribution of boundary conditions.     

A multiobjective optimization tool for Very Large Scale Integrated nonslicing floorplanning

Floorplanning is a vital phase in the design process of Very Large Scale Integrated (VLSI) circuit physical design process. The main objective of floorplanning is to minimize the area and wire length with the fixed‐outline constraints. Most of the tools developed so for are using weighted some approach. Hence, these tools suffer from weights assignment and undesirable bias toward particular objective. A tailor‐made multiobjective optimization tool could overcome this issue. In this article, we propose a new multiobjective optimization technique named self adaptive B*tree coded Archived Multiobjective Simulated Annealing Algorithm (AMOSA) and implemented to solve the VLSI nonslicing floorplanning problem. The proposed model provides choices from among different trade‐off solutions. The self adaptive B*tree coded AMOSA combines the novel cooling schedule, B*tree encoding, improved neighborhood search procedure, self adaptive local search, and the AMOSA. In B*tree coded AMOSA, the solution is represented using a B*tree. This representation causes a reduction in time and space complexity of AMOSA. The B*tree coded AMOSA is further improved with a novel cooling schedule, a self adaptive local search mechanism, and an improved neighborhood search procedure, resulting in further reduction of computational time and improvement in exploration capability. The FastSA, B*tree coded AMOSA, and the self adaptive B*tree coded AMOSA are tested with Microelectronics Center of North Carolina (MCNC) benchmarks. The results are compared and validated. The proposed method shows 59.8% improvement in the computational time for ami49 without changing the system quality. Copyright © 2012 John Wiley & Sons, Ltd.     

Investigation on combustion and emission characteristics of hydrogen-enriched dual-fuel engine operated under waste frying oil biodiesel

Using nonedible waste frying oil (WFO) as biodiesel and hydrogen in the mix composition may partly replace significant quantities of diesel fuel and help reduce fossil fuel reliance. The combination of diesel fuel, waste-fired biodiesel, and hydrogen gas can improve the performance, combustion, and emissions of single-fuel and dual-fuel diesel engines. This may lead to a novel alternative fuel mix pattern and modification for diesel engines, which is the research gap. Although there has been some research on waste-fired biodiesel and hydrogen gas-powered dual-fuel engines with the goal of partly replacing fossil fuels to a larger degree, there has been very little progress in this area. As a result, the current research effort focuses on using diesel fuel (100%, 30%, and 60%), waste-fired biodiesel (at 100%, 70%, and 40%), and hydrogen gas as fuel sources (5 and 10 liters per minute [LPM]). According to the current experiment, it was perceived in both dual-fuel and single-fuel modes. Under duel-fuel mode, the engine results for WFOB70D30 + H10 fuel blend had higher 4.2% (brake thermal efficiency [BTE]), 19.72% (oxides of nitrogen [NO_x]), and 9.09% (ignition delay [ID]) with a minimal range of (in-cylinder pressure, MFB, volumetric efficiency and heat release rate [HRR]) and a dropped rate of 4.34% (brake-specific energy consumption [BSEC]), 33.33% (carbon monoxide [CO]), 39.28% (hydrocarbons [HC]), 9.43% (smoke), and 6.97% (combustion duration [CD]) related to diesel fuel at peak load. However, single-fuel powered diesel engines provide minimal performance for the WFOB40D60 fuel blend with (11.32% lower BTE and 2.04% higher BSEC) and minimal rate of combustion (lower cylinder pressure, 2.12% minimal CD, 14.72% higher ID, minimal HRR combustion, volumetric efficiency, and MFB). Emitted fewer emissions (9.09% less CO, 4.87% less HC, 0.92% higher NO_x, and 1.69% more smoke) than diesel fuel at peak load. Therefore, it was concluded that adding 10 LPM of hydrogen gas to the biodiesel under a dual-fuel condition leads to better combustion, better performance, and less pollution than the single-fuel mode of operation.     

The Tenacity of an Inclined Fibre Bundle

The influence on the hairiness of open-end-spun yarns of the opening-roller speed, the linear density of the feed sliver, and the cleaning device that in some instances is coupled to spinning heads is studied and discussed, together with the influence of yarn twist and linear density. Experiments are reported on polyester-fibre, cotton, and polyester-fibre–cotton blended-fibre yarns.     

Atomic scale characterization of the conformational dynamics of a thermo-sensitive and a non-thermo-sensitive oligomer using vibrational spectra obtained from molecular dynamics

Molecular dynamics simulations (MD) are used to calculate the vibrational spectra of a thermo-sensitive oligomer, namely, poly(N-isopropylacrylamide) (PNIPAM) and a non-thermo-sensitive oligomer, namely, poly(acrylamide) (PAAM) and characterize the atomic scale conformations. Despite the structural similarity between the two polymers, the response of PNIPAM and PAAM to a thermal stimulus is widely different; a coil-to-globule transition is observed for PNIPAM above a lower critical solution temperature (LCST) of 305 K whereas the same is absent in PAAM. Simulations in both the cases are performed above and below the LCST of PNIPAM, namely at 278 K and 310 K, to evaluate the effect of temperature on the polymer conformations. The vibrational spectra of bonds involving atoms from the polymer backbone and the various side-groups (amide I, amide II, and isopropyl group of PNIPAM and amide I and amide II group of PAAM) of the polymers were analyzed to study the conformational changes in the polymer. The differences in the vibrational spectra are used to understand the dynamics of conformational transitions in the two polymers and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the polymer with water at two different temperatures, namely at 278 K and 310 K. The systematic trends in the observed peak intensities and frequency shifts at the low, medium, and high frequency end of the spectrum for the various atoms in the two polymers are rationalized on the basis of bond-lengths, local coordination, strength of hydrogen bonding, and neighboring solvation environment. The analysis of the vibrational spectra for amide I and amide II regions of PNIPAM suggests a coil-to-globule transition in going from 278 K to 310 K. The differences are evaluated in terms of the strength, stability, and structure of the hydrogen-bond network between polymer and polymer and between polymer and water. Comparison of the vibrational spectra of isopropyl groups in PNIPAM at 278 K and 310 K suggests dehydration of the isopropyl moieties at 310 K. In the case of PNIPAM, we observe that polymer-water interactions are dominant below the LCST whereas polymer–polymer interactions dominate above the LCST. On the other hand, the vibrational spectra of amide I and amide II group of PAAM, at 278 K and 310 K, do not show any significant difference in terms of the interactions between polymer and polymer and interactions between polymer and water. Analysis of the peak intensities, of the amide II stretching band, observed in the frequency range 3500–3700 cm^?1 suggests that the fraction of bonded and non-bonded hydrogen atoms are similar at both 278 K and 310 K. This indicates that the interactions between polymer and polymer and between polymer and water are similar at both the temperatures. The interactions between PAAM and its surrounding environment are found to be unaffected as the temperature is raised from 278 K to 310 K. Comparisons with experimental studies are made where possible. Our study provides useful insights into the nature of various inter-molecular interactions and their role in influencing the atomic scale conformational dynamics in oligomers.     

Investigation of solid supported dendrimers for water disinfection

Polystyrene copolymer beads supported dendrimer was synthesized and investigated for its biological applications. Macroporous cross‐linked polystyrene copolymer beads were synthesized using suspension polymerization. Two successive generations of di(chloroethyl) amine‐type end group functionality was formed on the polystyrene copolymer beads. Elemental analysis, Fourier transform infrared spectra, and solid state ¹³C NMR spectra were employed to characterize the polymer bound dendrimer. The polymer bound dendrimer was tested for antibacterial action against both Gram‐positive and Gram‐negative bacteria. The activity against both types of organism increased with an increase in the nitrogen atoms in the polymer back bone. The dendritic structure containing both amino and di(chloroethyl) groups showed significant reduction in the bacterial count when kept in 20 mL autoclaved water with bacterial cultures having an initial count in the range of 12–83 × 10⁶ CFU/mL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Diffeomorphic sulcal shape analysis on the cortex

We present a diffeomorphic approach for constructing intrinsic shape atlases of sulci on the human cortex. Sulci are represented as square-root velocity functions of continuous open curves in R3, and their shapes are studied as functional representations of an infinite-dimensional sphere. This spherical manifold has some advantageous properties--it is equipped with a Riemannian L2 metric on the tangent space and facilitates computational analyses and correspondences between sulcal shapes. Sulcal shape mapping is achieved by computing geodesics in the quotient space of shapes modulo scales, translations, rigid rotations, and reparameterizations. The resulting sulcal shape atlas preserves important local geometry inherently present in the sample population. The sulcal shape atlas is integrated in a cortical registration framework and exhibits better geometric matching compared to the conventional euclidean method. We demonstrate experimental results for sulcal shape mapping, cortical surface registration, and sulcal classification for two different surface extraction protocols for separate subject populations.