On the prediction of the roundness error in BTA deep hole machining based on the stochastic description of the cutting tool motion

This paper presents a methodology of predicting the maximum possible out-of-roundness of the hole produced, in BTA deep hole machining, as a function of certain machining parameters. Based on the solutions of the stochastic differential equations representing the machine tool-workpiece system in BTA deep hole machining, and the true cutting tool motion, an index describing the upper bound of the roundness error is defined. A parametric analysis of the out-of-roundness index is carried out. This analysis points out that at a low length-to-diameter ratio of the cutting tool, the axial force is the predominant factor causing the tool-tip deviation from the ideal motion, and that the radial and tangential forces are the major causes for the tool tip deviation at high length-to-diameter ratio of the cutting tool. The experimental measurement of out-of-roundness of the specimens under different machining conditions shows that the roundness error obtained lies within the zone described by the theoretical prediction.     

Potential visible WO3/GO composite photocatalyst

Graphene oxide (GO) was synthesized by Hummers method. GO and tungsten oxide (WO₃) composites were successfully prepared by deposition of WO₃ on GO surface to make efficient visible light catalyst. Scanning electron microscopy of pure GO revealed that GO films are folded with kinked and wrinkled edges. The interspaces layers are partially filled by WO₃ nanoparticles with their less wrinkled edges and smooth surface of composite. Moreover, composite sheets are thin and transparent which allow easy penetration of light. EDS showed the presence of C, O, and W in GO/WO₃ composites with no impurity. UV-Vis diffused reflectance spectra showed red shift with the increase in WO₃ contents. Raman spectra of GO and GO/WO₃ composite show G and D bands. These bands reduced in intensity in composite sample due to removal of oxygenated functional groups with some new peaks of WO₃. FT-IR confirmed successful oxidation of graphite into GO with reduction in GO because oxide-related bond groups decrease after reduction. The transmittance peaks of WO₃ in composite sample are appeared indicating W-O-C linkages. The highest visible light activity of the composite is due to easy penetration of light with deposition of WO₃, low band gap, and new linkages.     

Polymorphic information and genetic diversity in <i>Brassica</i> species revealed by RAPD markers

Randomly amplified polymorphic DNA (RAPD) is a tremendously convenient approach used to discriminate between Brassica species owing to its accuracy and speed. RAPD primers generate adequate genetic information that can be used in the primer-marker system. In this work, twenty RAPD-PCR based markers were executed to generate polymorphic data, like polymorphic information content (PIC), mean resolving power (MRP), resolving power (RP), effective multiplex ratio (EMR), and marker index (MI) for the first time and genetic distance among and between six Brassica species were calculated. Our results indicated that 20 primers produced a total of 231 scored band and generated 87% polymorphic bands. Average PIC, MRP, RP, MI, and EMR values were 0.088, 0.65, 6.7, 0.78, and 8.9, respectively. PIC showed an overall negative correlation with MRP, RP, MI, and EMR, whereas MRP, RP, and EMR, were positively correlated with each other. Genetic identities ranged from 41.99% (between Brassica napus and Brassica oleracea) to 68.83% (between Brassica campestris and Brassica oleracea). Dendrogram results showed no clustering between species except between Brassica campestris and Brassica nigra. Nevertheless, these results will be helpful to acquire useful information about the markers and their use to determine the genomic structures of Brassica species. Further, based on genetic distance and polymorphic information, new hybrids can be developed for effective oilseed production.     

Optimization of mechanical properties of in situ polymerized poly(methyl methacrylate)/alumina nanoparticles nanocomposites using Taguchi approach

Polymer Bulletin - Alumina nanoparticles are among important metal oxides with specific properties but chemically incompatible with an organic matrix such as poly(methyl methacrylate) (PMMA). In...     

Optimal distribution function determination for plus fraction splitting

Reservoir fluid modelling is one of the most important steps in reservoir simulation and modelling of flow lines as well as surface facilities. One of the most uncertain parameters of the reservoir fluids is the plus fraction. An accurate and consistent splitting scheme can reduce this uncertainty and as a result, enhance the modelling of reservoir fluids. The existing schemes for splitting plus fractions are all based on assuming a specific mole fraction‐molecular weight distribution with predefined constant values that may yield inaccurate and inconsistent results. In this study, an optimization‐based algorithm was developed to determine the aforementioned controlling parameters of the plus fraction distribution function, enforcing the relationship between specific gravity and molecular weight of the single carbon numbers (SCNs). The introduced optimization‐based splitting technique was applied to different samples, covering a wide range of reservoir fluids, including gas condensates, volatile oils, black oils, and heavy oils. The results showed that the proposed technique yielded a more consistent molecular weight‐mole fraction distribution concerning the experimental extended analysis of plus fractions, yielding an average relative error of 25.8 % compared to 76, 33.6, and 45.9 % for the Katz, Ahmed, and Whitson methods, respectively. It was also shown that the proposed method results in more accurate and more consistent phase behaviour predictions than the existing methods concerning the experimental data. Furthermore, the results showed that the introduced optimization‐based method yields monotonic split samples regarding specific gravity and molecular weight, while the conventional techniques do not guarantee to preserve the monotonicity.     

Processable Thermally Conductive Polyurethane Composite Fibers

The demand for wearable electronics has resulted in an increasing interest in the development of functional fibers, with a specific focus upon the development of electrically conductive fibers incorporable into garments. However, the production of thermally conductive fibers for heat dissipation has been largely neglected. Owing to the very rapid development of miniaturized wearable electronics, there is an increasing need for the development of thermally conductive fibers as heat sinks and thermal management processes. In this study, thermally conductive but electrically insulating boron nitride nanopowder (BNNP) fillers are used to effectively enhance the thermal conductivity and mechanical properties of elastomeric polyurethane fibers. Thermal conductivity enhancement of more than 160% is achieved at very low loadings of BNNP (less than 5 wt%) with an improvement in the mechanical properties of the unmodified fiber. These thermally conductive fibers are also incorporated into 3D textile structures as a proof of processability.     

Identification and Field Evaluation of the Sex Pheromone of <Emphasis Type="Italic">Orthaga achatina</Emphasis> (Lepidoptera: Pyralidae)

Orthaga achatina (Lepidoptera: Pyralidae) is the most serious pest in south China of camphor trees, Cinnamomum camphora (L.) Presl, an important urban tree species. Gas chromatography-electroantennographic detection (GC-EAD) of the sex pheromone of O. achatina showed three EAD-active components. Coupled gas chromatography/mass spectrometry analyses identified these as (Z)-11-hexadecenol (Z11–16:OH), (Z)-11-hexadecenyl acetate (Z11–16:OAc), and (3Z,6Z,9Z,12Z,15Z)-tricosapentaene (Z3,Z6,Z9,Z12,Z15–23:H). In field tests using different combinations of the three compounds, male moths were attracted to a mixture of Z11–16:OAc and Z3,Z6,Z9,Z12,Z15–23:H, but less attracted to other blends. Further field tests with different ratios of the two compounds determined the optimal ratio of the binary blend as 500:250. The addition of Z11–16:OH to Z11–16:OAc, or to the binary mixture of Z11–16: OAc and the pentaene did not yield higher catches. This shows that O. achatina uses a mixture of Type I and Type II sex pheromone components. Orthaga achatina is the third Pyraloidea species found to utilize Z3,Z6,Z9,Z12,Z15–23:H as a sex pheromone component.     

Raman calibration of the HT-7 yttrium aluminum garnet Thomson scattering for electron density measurements

A multipulse neodym doped yttrium aluminum garnet laser Thomson scattering system calibrated by the anti-Stokes rotational Raman scattering from nitrogen gas had been developed in the HT-7 superconducting Tokmak. By virtue of this system, measured electron density results of the plasma were obtained. The results showed good repeatability and its total uncertainty was estimated to be +/-18%.     

Algorithms for Handoff Minimization in Wireless Networks

Journal of Computer Science and Technology - This study focuses on the problem of handoff minimization for a set of users moving in a wireless network. This problem is analyzed by considering two...     

Determining speaker attributes from stress-affected speech in emergency situations with hybrid SVM-DNN architecture

Multimedia Tools and Applications - In the millions of emergency reporting calls made each year, about a quarter are non-emergencies. To avoid responding to such situations, forensic examination of...