State-of-the-art technology in variable compression ratio mechanism for spark ignition engine

Present investigations deal with development of a novel variable compression ratio (VCR) mechanism and its implementation in a small and relatively large size single-cylinder engines. Operation of this mechanism is found to be smooth and effective in the running condition of the engine as well. This mechanism, when incorporated in the small size spark ignition HONDA engine, portrayed improvement in engine performance with increment in compression ratio (CR) for petrol and kerosene. Their respective optimum CRs 5.02 (petrol) and 5.27 (kerosene) are higher than the base value 4.8. In case of large size KIRLOSKAR engine, the present VCR mechanism is found to be useful while operating with liquefied petroleum gas (LPG), where measurements showed that combustion duration is lower with LPG for CR 9.79 as compared with base value 9.0. The present experiments clearly demonstrate the usefulness of VCR mechanism in improving engine performance for a given fuel and broadening the range of alternative fuels burnt in the engine. Ease of fabrication, simplicity in installation, accessibility in troubleshooting and smooth run-time alterations are the advantages with the current novel mechanism.     

Visualization of dynamic fiber-matrix interfacial shear debonding

To visualize the debonding event in real time for the study of dynamic crack initiation and propagation at the fiber–matrix interface, a modified tension Kolsky bar was integrated with a high-speed synchrotron X-ray phase-contrast imaging setup. In the gage section, the pull-out configuration was utilized to understand the behavior of interfacial debonding between SC-15 epoxy matrix and S-2 glass fiber, tungsten wire, steel wire, and carbon fiber composite Z-pin at pull-out velocities of 2.5 and 5.0 m s^?1. The load history and images of the debonding progression were simultaneously recorded. Both S-2 glass fiber and Z-pin experienced catastrophic interfacial debonding whereas tungsten and steel wire experienced both catastrophic debonding and stick–slip behavior. Even though S-2 glass fiber and Z-pin samples exhibited a slight increase and tungsten and steel wire samples exhibited a slight decrease in average peak force and average interfacial shear stress as the pull-out velocities were increased, no statistical difference was found for most properties when the velocity was increased. Furthermore, the debonding behavior for each fiber material is similar with increasing pull-out velocity. Thus, the debonding mechanism, peak force, and interfacial shear stress were rate insensitive as the pull-out velocity doubled from 2.5 to 5.0 m s^?1. Scanning electron microscope imaging of recovered epoxy beads revealed a snap-back behavior around the meniscus region of the bead for S-2 glass, tungsten, and steel fiber materials at 5.0 m s^?1 whereas those at 2.5 m s^?1 exhibited no snap-back behavior.     

An improved multimodal medical image fusion scheme based on hybrid combination of nonsubsampled contourlet transform and stationary wavelet transform

This research proposes an improved hybrid fusion scheme for non-subsampled contourlet transform (NSCT) and stationary wavelet transform (SWT). Initially, the source images are decomposed into different sub-bands using NSCT. The locally weighted sum of square of the coefficients based fusion rule with consistency verification is used to fuse the detailed coefficients of NSCT. The SWT is employed to decompose approximation coefficients of NSCT into different sub-bands. The entropy of square of the coefficients and weighted sum-modified Laplacian is employed as the fusion rules with SWT. The final output is obtained using inverse NSCT. The proposed research is compared with existing fusion schemes visually and quantitatively. From the visual analysis, it is observed that the proposed scheme retained important complementary information of source images in a better way. From the quantitative comparison, it is seen that this scheme gave improved edge information, clarity, contrast, texture, and brightness in the fused image.     

3D true-phase polarity recovery with independent phase estimation using three-tier stacks based region growing (3D-TRIPS)

Objectives

A postprocessing technique termed 3D true-phase polarity recovery with independent phase estimation using three-tier stacks based region growing (3D-TRIPS) was developed, which directly reconstructs phase-sensitive inversion-recovery images without acquisition of phase-reference images. The utility of this technique is demonstrated in myocardial late gadolinium enhancement (LGE) imaging.

Materials and methods

A data structure with three tiers of stacks was used for 3D-TRIPS to directly achieve reliable region growing for successful background-phase estimation. Fifteen patients undergoing postgadolinium 3D phase-sensitive inversion recovery (PSIR) cardiac LGE magnetic resonance imaging (MRI) were recruited, and 3D-TRIPS LGE reconstructions were compared with standard PSIR. Objective voxel-by-voxel comparison was performed. Additionally, blinded review by two radiologists compared scar visibility, clinical acceptability, voxel polarity error, or groups and blurring.

Results

3D-TRIPS efficiently reconstructed postcontrast phase-sensitive myocardial LGE images. Objective analysis showed an average 95% voxel-by-voxel agreement between 3D-TRIPS and PSIR images. Blinded radiologist review demonstrated similar image quality between 3D-TRIPS and PSIR reconstruction.

Conclusion

3D-TRIPS provided similar image quality to PSIR for phase-sensitive myocardial LGE MRI reconstruction. 3D-TRIPS does not require acquisition of a reference image and can therefore be used to accelerate phase-sensitive LGE imaging.

     

Evaluation of layout and atmospheric stability effects in wind farms using large‐eddy simulation

Large‐eddy simulation (LES) has been used previously to study the effect of either configuration or atmospheric stability on the power generated by large wind farms. This is the first study to consider both stability and wind farm configuration simultaneously and methodically with LES. Two prevailing wind directions, two layouts (turbines aligned versus staggered with respect to the wind) and three stabilities (neutral and moderately unstable and stable) were evaluated. Compared with neutral conditions, unstable conditions led to reduced wake losses in one configuration, to enhanced wake losses in two and to unchanged wake losses in one configuration. Conversely, stable conditions led to increased wake losses in one, decreased wake losses in two and unchanged wake losses in one configuration. Three competing effects, namely, rates of wake recovery due to vertical mixing, horizontal spread of wakes and localized regions of acceleration caused by multiple upstream wakes, were identified as being responsible for the observed trends in wake losses. The detailed flow features responsible for these non‐linear interactions could only be resolved by the LES. Existing analytical models ignore stability and non‐linear configuration effects, which therefore need to be incorporated. Copyright © 2017 John Wiley & Sons, Ltd.     

Recovery of allyl isothiocyanate from steam distillation condensate using adsorption

This paper describes the results of a study on use of the adsorption–regeneration technique for recovery of dissolved allyl isothiocyanate(AITC) which is present in significant quantities in steam distillation condensate of mustard essential oil (MEO). Equilibrium and dynamic breakthrough studies were carried out. The adsorbents used were polymeric adsorbents: Amberlite XAD‐2, Amberlite XAD‐4, Amberlite XAD‐7, NPA‐1 and NPA‐2. The results obtained indicate that Amberlite XAD‐4 is the best amongst these various adsorbents. AITC recoveries in excess of 95% were obtained, indicating the feasibility of this approach. Further, since no chemical reactions are involved the recovered AITC retains its ‘natural’ origin. © 2000 Society of Chemical Industry     

Antimony polymers. III. Flame retardant behavior of chloroprene and natural rubber vulcanizates with antimony polymer

The antimony-containing polymer of bisphenol-A (BPA) and triphenyl antimony dinitrate was used as a flame retardant (FR) for chloroprene rubber (CR) and natural rubber (NR). The flame retardancy of this additive was monitored by the limiting oxygen index (LOI) measurements of the rubber vulcanizates and compared with that for antimony trioxide used as a FR additive. The thermogravimetric analysis (TGA) of the vulcanizates has also been studied. A structure flammability relationship has been established. The effect of this FR additive on physical properties of the vulcanizates undergoing heat aging and solvent leaching has also been evaluated. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 927–935, 1998     

Effect of Germination on the Functional and Moisture Sorption Properties of High–Pressure-Processed Foxtail Millet Grain Flour

Foxtail millet is one of the commonly cultivated, nutritionally competitive source of protein, fibre, phytochemicals and other micronutrients, as compared to major cereals like wheat and rice. Considering the potential of these grains, the high pressure processed flours of germinated (GFMF) and non-germinated foxtail millet (NGFMF) grains were studied for its functional, moisture sorption and thermodynamic properties. Germination and high-pressure processing of foxtail millet grains significantly improved the functional properties of the flour. Apart from this, the moisture sorption isotherms of both the flours were determined at 10, 25 and 40 °C and the sorption data was fitted to Guggenheim-Anderson-De Boer (GAB) sorption model. The monolayer moisture content for NGFMF and GFMF ranged between 3.235–2.364 and 2.987–2.063 g g^?1, respectively. The isosteric heat of sorption ranged between ? 76.35 to ? 38.23 kJ mol^?1 for NGFMF and 172.55 to ? 34.02 kJ mol^?1 for GFMF at a moisture range of 0 to 36%, whereas, the integral entropy of sorption for NGFMF ranged between ? 0.404 and ? 0.120 kJ mol^?1 K^?1 and for GFMF between ? 0.667 and ? 0.383 kJ mol^?1 K^?1. Along with the validation of the compensation theory, the values of spreading pressures lied in the range of 0–0.078 J m^?2 for NGFMF and 0– 0.124 J m^?2 for GFMF, while, the glass transition temperatures ranged between 82.25 and 28.67 °C for NGFMF and from 51.11 to 11.83 °C for GFMF at all three temperatures.     

Conjugate Heat Transfer Analysis for a Finite Thickness Cylinder in a Hypersonic Flow

Prediction of surface heating rates is of prime importance for the hypersonic flow regime. Experimental and conventional computational efforts overlook the heat transfer phenomenon in the solid due to the rigid assumptions involved in the solution methodologies. In order to address this fact, conjugate heat transfer (CHT) studies are carried out using various coupling techniques to examine their implementation abilities. Three types of solution methodologies are adopted, namely, decoupled, strongly coupled, and loosely coupled analysis. This study is also focused on looking into the effect of a hypersonic flow field on wall heat flux for a finite thickness insulating cylinder at moderately large time scales. Increase in wall temperature and decrease in surface heat flux have been noticed using strong and loose coupling techniques with an increase in simulation time. Decoupled fluid and solid domain analysis is found to be useful for typical shock tunnel test durations (～1 ms) while investigations with loose coupling techniques are advisable for time scales corresponding to flight testing (～1 s). Efforts are also made to reason the discrimination in prediction of stagnation point heat flux using conventional computational and experimental analysis.