Modelling of specific energy requirement during high-efficiency deep grinding

Grinding is a multi-point cutting operation. The specific energy or the energy expended for unit material removal in grinding is very high, typically one or two orders higher than the machining specific energy. Such high specific energy required in grinding can be attributed to the irregular and random geometry of the abrasive grits, which induce a lot of rubbing and ploughing actions along with the chip formation by shearing process. Also the effective angle in grinding is highly negative which is again responsible for such high-specific energy requirement in grinding. In grinding, a number of notable phenomena occur during the chip formation process, which actually consumes a significant percentage of energy. Such main energy consumers in grinding are:

• Chip formation due to shearing

• Primary rubbing

• Secondary rubbing

• Ploughing

• Wear flat rubbing

• Friction between the loaded chip and workpiece

• Friction between bond and workpiece, etc.

The present paper tries to analytically predict the specific energy consumed during high-efficiency deep grinding (HEDG) of bearing steel by monolayer cBN wheel. During the HEDG process, energy is spent mostly for shearing, rubbing and ploughing processes. The other energy consumers have insignificant role in such high-speed grinding process. So, models which take into account the processes of shearing, primary rubbing, secondary rubbing and ploughing process can reasonably be used to predict the energy requirement in such HEDG process. The total specific energy value obtained from the model has been validated with those experimentally observed values. A good trend matching of the modelled and experimental values have been observed and the root mean square error values have been found to vary between 7% and 11%.     

Mechanical properties of injection molded long fiber polypropylene composites,Part 1: Tensile and flexural properties

Innovative polymers and composites are broadening the range of applications and commercial production of thermoplastics. Long fiber‐reinforced thermoplastics have received much attention due to their processability by conventional technologies. This study describes the development of long fiber reinforced polypropylene (LFPP) composites and the effect of fiber length and compatibilizer content on their mechanical properties. LFPP pellets of different sizes were prepared by extrusion process using a specially designed radial impregnation die and these pellets were injection molded to develop LFPP composites. Maleic‐anhydride grafted polypropylene (MA‐g‐PP) was chosen as a compatibilizer and its content was optimized by determining the interfacial properties through fiber pullout test. Critical fiber length was calculated using interfacial shear strength. Fiber length distributions were analyzed using profile projector and image analyzer software system. Fiber aspect ratio of more than 100 was achieved after injection molding. The results of the tensile and flexural properties of injection molded long glass fiber reinforced polypropylene with a glass fiber volume fraction of 0.18 are presented. It was found that the differences in pellet sizes improve the mechanical properties by 3–8%. Efforts are made to theoretically predict the tensile strength and modulus using the Kelly‐Tyson and Halpin‐Tsai model, respectively. POLYM. COMPOS., 28:259–266, 2007. © 2007 Society of Plastic Engineers     

Thermodynamic modeling of the Cr-Pd and Mo-Pd systems

To assist the quantitative design of ultra-high strength (UHS) quantum steels containing Pd, a set of self-consistent thermodynamic model parameters is presented to describe the phase equilibria of the Cr-Pd and Mo-Pd systems. These thermodynamic parameters are of importance to control the kinetics of solid-solid phase transformations, such as martensitic transformation, and precipitation of M₂C carbide and austenite, relevant to the design of UHS steels in the Fe-C-Co-Cr-Mo-Ni-Pd system. The present thermodynamic modeling complements our previous report on the thermodynamic modeling of the Co-Pd, Fe-Pd, and Ni-Pd systems to facilitate quantitative design of UHS quantum steels.     

Influence of organoclay dispersion on air retention and fatigue resistance of tyre inner liner compound

In a pneumatic tire, the contained air carries the load of the vehicle and also augments performance for other functional requirements, such as, rolling resistance, ride and handling, durability, and so on. The inner liner of the tire is responsible to ensure air retention by virtue of its high air impermeability. The present study focused on developing inner-liner compounds of improved air impermeability by utilizing platelet filler (layered silicate). The obtained organoclay was subjected to a pre-treatment process called exfoliation to increase the d spacing between the clay layers that further improved the morphological aspect of the compound. The inner-liner compound has been modified by partial replacement of carbon black with organically modified bentonite clay in 1:1 and 2.5:1 ratio. Air impermeability of rubber compounds was tested in a gas permeability tester. Field emission scanning electron microscope, transmission electron microscope, atomic force microscope, and x-ray diffraction were utilized to understand the distribution and dispersion of clay in the rubber compounds. Fatigue crack growth analysis was carried out to measure the fatigue life of the materials. The modified compounds exhibited air impermeability improvement from 7% to 30% vs the reference carbon-black filled compound with improved mechanical properties and filler dispersion.     

On-demand fuzzy clustering and ant-colony optimisation based mobile data collection in wireless sensor network

Wireless Networks - In a wireless sensor network (WSN), sensor nodes collect data from the environment and transfer this data to an end user through multi-hop communication. This results in high...     

Effects of Defects on Charge Transport in Armchair Nanoribbon WS2 Field Effect Transistors

We have studied the WS₂ armchair nanoribbon with various defects like vacancy, edge roughness, twist, turn and ripple and compared how the bandgap changes due to such defects with the bandgap of a nanoribbon with no defects. Materials like WS₂ and other transition metal dichalcogenides (MX₂) have a graphene like layered structure with hexagonal rings and have properties that have attracted a lot of interest. Hence it is essential to study the changes in the band structure of the nanoribbon of WS₂ due to the inclusion of defects like vacancy, rough edge, wrap, ripple and twist for making any device based on WS₂.     

Study of photovoltaic performance of host‐guest system comprising photoluminescent polyurethane and rhodamine B dye

The photovoltaic property of Rhodamine B dye embedded into Poly(tolyl‐1,1′‐binaphthyl carbamate) (PU₁) and poly(hexamethylene‐1,1′‐binaphthyl carbamate) (PU₂) matrices have been evaluated using host‐guest approach. The photoactive layer comprising photoluminescent polymer matrix (PU₁ or PU₂), Rhodamine B and TiO₂ nanoparticles were prepared by spin casting method. The power conversion efficiency (PCE) the photovoltaic devices based on PU₁ and PU₂ matrices were found to be 0.043% and 0.029%, respectively. PCE of the photovoltaic devices were limited due to low lying highest occupied molecular orbital of PU₁ and PU₂ polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Deep neural networks for automatic grain-matrix segmentation in plane and cross-polarized sandstone photomicrographs

Applied Intelligence - Grain segmentation of sandstone that is partitioning the grain from its surrounding matrix/cement in the thin section is the primary step for computer-aided mineral...