FastV: From-point Visibility Culling on Complex Models

We present an efficient technique to compute the potentially visible set (PVS) of triangles in a complex 3D scene from a viewpoint. The algorithm computes a conservative PVS at object space accuracy. Our approach traces a high number of small, volumetric frusta and computes blockers for each frustum using simple intersection tests. In practice, the algorithm can compute the PVS of CAD and scanned models composed of millions of triangles at interactive rates on a multi-core PC. We also use the visibility algorithm to accurately compute the reflection paths from a point sound source. The resulting sound propagation algorithm is 10–20X faster than prior accurate geometric acoustic methods.     

Toward Facile Preparation and Design of Mulberry-Shaped Poly(2-methylaniline)-Ce2(WO4)3@CNT Nanocomposite and Its Application for Electrochemical Cd2+ Ion Detection for Environment Remediation

Novel hybrid material was prepared by adding slurries of poly(N-methylaniline) and cerium tungstate [Ce₂(WO₄)₃] into a conical flask contained dispersed carbon nanotubes. It was characterized by scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Electrical conductivity of poly(N-methylaniline)-Ce₂(WO₄)₃@carbon nanotube samples was determined using four-probe method. The thin layer of poly(N-methylaniline)-Ce₂(WO₄)₃@carbon nanotube was fabricated onto glassy carbon electrode for a selective Cd²⁺ ion sensor. The calibration plot is linear (r²?=?0.9917) over the large Cd²⁺ concentration ranges (1.0?nM–1.0?mM). The sensitivity, detection limit is ～5.138?µA?µM^?1?cm^?2 and ～0.11?nM (signal-to-noise ratio, at a SNR of 3), respectively.     

Security risk assessment: Applying the concepts of fuzzy logic

Chemical process industries (CPI) handling hazardous chemicals in bulk can be attractive targets for deliberate adversarial actions by terrorists, criminals and disgruntled employees. It is therefore imperative to have comprehensive security risk management programme including effective security risk assessment techniques. In an earlier work, it has been shown that security risk assessment can be done by conducting threat and vulnerability analysis or by developing Security Risk Factor Table (SRFT). HAZOP type vulnerability assessment sheets can be developed that are scenario based. In SRFT model, important security risk bearing factors such as location, ownership, visibility, inventory, etc., have been used. In this paper, the earlier developed SRFT model has been modified using the concepts of fuzzy logic. In the modified SRFT model, two linguistic fuzzy scales (three-point and four-point) are devised based on trapezoidal fuzzy numbers. Human subjectivity of different experts associated with previous SRFT model is tackled by mapping their scores to the newly devised fuzzy scale. Finally, the fuzzy score thus obtained is defuzzyfied to get the results. A test case of a refinery is used to explain the method and compared with the earlier work.     

Multi-response optimization of process parameters based on response surface methodology for pure titanium using WEDM process

This paper presents an investigation on WEDM of pure titanium (grade-2). An attempt has been made to model the four response variables, i.e., machining rate, surface roughness, dimensional deviation and wire wear ratio in WEDM process using response surface methodology. The experimental plan is based on Box–Behnken design. The six parameters, i.e., pulse on time, pulse off time, peak current, spark gap voltage, wire feed and wire tension have been varied to investigate their effect on output responses. These responses have been optimized using multiresponse optimization through desirability. The ANOVA has been applied to identify the significance of developed model. The test results confirm the validity and adequacy of the developed RSM model. Finally, the optimum parametric setting has been designed for the optimization of process.     

Comparative Effects of Sandalwood Seed Oil on Fatty Acid Profiles and Inflammatory Factors in Rats

The aim of the present study was to investigate the effect of sandalwood seed oil on fatty acid (FA) profiles and inflammatory factors in rats. Fifty male Sprague–Dawley rats were randomly divided into five different dietary groups: 10 % soybean oil (SO), 10 % olive oil (OO), 10 % safflower oil (SFO), 10 % linseed oil (LSO) and 8 % sandalwood seed oil blended with 2 % SO (SWSO) for 8 weeks. The SWSO group had a higher total n-3 polyunsaturated fatty acids (PUFA) levels but lower n-6:n-3 PUFA ratios in both adipose tissue and liver than those in the SO, OO and SFO groups (p < 0.05). Although the SWSO group had a much lower 18:3n-3 level (4.51 %) in their dietary lipids than the LSO group (58.88 %), the levels of docosahexaenoic acid (DHA: 22:6n-3) in liver lipids and phospholipids of the SWSO group (7.52 and 11.77 %) were comparable to those of the LSO group (7.07 and 13.16 %). Ximenynic acid, a predominant acetylenic FA in sandalwood seed oil, was found to be highly incorporated into adipose tissue (13.73 %), but relatively lower in liver (0.51 %) in the SWSO group. The levels of prostaglandin F_2α, prostaglandin E₂, thromboxane B₂, leukotriene B₄, tumor necrosis factor-α and interleukin-1β in both liver and plasma were positively correlated with the n-6:n-3 ratios, suggesting that increased n-6 PUFA appear to increase the formation of pro-inflammatory cytokines, whereas n-3 PUFA exhibit anti-inflammatory activity. The present results suggest that sandalwood seed oil could increase tissue levels of n-3 PUFA, DHA and reduce the n-6:n-3 ratio, and may increase the anti-inflammatory activity in rats.     

Chisel edge and cutting lip shape optimization for improved twist drill point design

This paper investigates the optimization of twist drill point geometries in order to minimize thrust and torque in drilling. A point geometry parameterization based on the drill grinding parameters is used to ensure manufacturability of the optimized geometry. Three commonly used drill point geometries, namely, conical, Racon^® and helical, are optimized for drilling forces while maintaining the inherent characteristics of each of the profiles. A significant reduction is shown in the drilling forces for the optimized drills. Drills with the optimized conical point profile are produced and tests run to validate the reduction in thrust and torque.     

Mechanistic investigation of the oxidation of Cefuroxime by hexacyanoferrate(III) in alkaline conditions

The reactions of Cefuroxime (CFA) by hexacyanoferrate (III) (HCF(III)) in alkaline medium at a constant ionic strength has been studied spectrophotometrically. It is a first order reaction, but fractional order in both CFA and alkali. Decrease in dielectric constant of the medium decreases the rate of reaction. The effect of added products and ionic strength has also been investigated. A mechanism involving free radicals is proposed. In a composite equilibrium step, CFA binds to HCF(III) to form a complex that subsequently decomposes to the products. The main two products were separated and identified by column chromatography, TLC and FT-IR. There is good agreement between the observed and calculated rate constants under different experimental conditions. The reaction was studied at different temperatures and activation parameters were computed with respect to the slow step of the proposed mechanism.     

Development of Ultrafine-Grained Dual-Phase Steels: Mechanism of Grain Refinement During Intercritical Deformation

Heavy deformation of metastable austenite (below A_e3) or both austenite and ferrite in the two-phase region (between A_r3 and A_r1) is known to develop an ultrafine ferrite grain structure with an average grain size of less than 3 μm. Different dynamic softening mechanisms, such as dynamic recovery, dynamic recrystallization, and dynamic strain-induced austenite→ferrite transformation (DSIT), are responsible for such grain refinement. However, the sequence of those metallurgical events and the temperature range over which any particular mechanism dominates is not yet well understood. The current study throws some light on this aspect by applying heavy, single-pass compressive deformation (with true strain of 1.0) on the microalloyed steel samples over a temperature range of 1173 K to 873 K (900 °C to 600 °C) using a Gleeble simulator (Dynamic Systems Inc., Poestenkill, NY) and water quenching the samples immediately after deformation. The current study showed the dominating effect of the following mechanisms with respect to the deformation temperature: (1) DSIT followed by conventional dynamic recrystallization (Conv-DRX) of ferrite at higher deformation temperatures (≥1073 K [800 °C]), (2) extended recovery and continuous dynamic recrystallization (Cont-DRX) of ferrite at intermediate deformation temperatures (~1023 K [750 °C]), and (3) simple dynamic recovery of ferrite at lower deformation temperatures (≤923 K [650 °C]).