Reusable Dry Adhesive: Aluminium-Aluminium Bonding by Self-Vulcanisable Blend Based on Carboxylated Nitrile Rubber and Chlorobutyl Rubber

A self-vulcanisable blend of chlorobutyl rubber and carboxylated nitrile rubber can be used as an adhesive for aluminium-aluminium bonding. The peel strength depends on the state of cure of the adhesive, testing temperature and carboxyl content of the carboxylated nitrile rubber. At moulding times below 15 minutes, the adhesive was found to be reusable after repeated post-peel mouldings.     

Kinetics of structure II gas hydrate formation for propane and ethane using an in-situ particle size analyzer and a Raman spectrometer

The kinetics of structure II gas hydrates, formed from pure propane and a mixture of propane and ethane, were investigated and intrinsic rate constants were regressed from the experimental data. The experiments were conducted in a semi-batch stirred tank reactor equipped with an in-situ particle size analyzer and connected to an external Raman spectrometer. Experiments were conducted with pure propane at temperatures ranging from 274 to 276 K and pressures ranging from 0.39 to 0.43 MPa. The intrinsic rate constant for ethane in structure II was subsequently regressed from experimental data on the formation of hydrates formed from an equimolar mixture of propane and ethane at 274 K and 0.35 MPa. Raman spectroscopy was used to verify that ethane was present only in the large sII cavity.     

Accelerating compute intensive medical imaging segmentation algorithms using hybrid CPU-GPU implementations

Medical image processing is one of the most famous image processing fields in this era. This fame comes because of the big revolution in information technology that is used to diagnose many illnesses and saves patients lives. There are many image processing techniques used in this field, such as image reconstructing, image segmentation and many more. Image segmentation is a mandatory step in many image processing based diagnosis procedures. Many segmentation algorithms use clustering approach. In this paper, we focus on Fuzzy C-Means based segmentation algorithms because of the segmentation accuracy they provide. In many cases, these algorithms need long execution times. In this paper, we accelerate the execution time of these algorithms using Graphics Process Unit (GPU) capabilities. We achieve performance enhancement by up to 8.9x without compromising the segmentation accuracy.     

Collusion attacks mitigation in internet of things: a fog based model

Multimedia Tools and Applications - Collusion attacks are among the major security concerns nowadays due to the growth exposure in networks and communications. Internet of Things (IoT) environments...     

Directional solidification of Al- Ni/SiC composites during parabolic trajectories

Aluminum-6.1 wt pct nickel-silicon carbide composites containing varying volume fractions and particle sizes of SiC were directionally solidified at different translation rates and temperature gradi-ents, under variable gravity levels. The gravity level was changed by solidifying the composites in a Bridgman type directional solidification furnace aboard NASA KC-135 aircraft, flying on parabolic trajectories. It was observed that high gravity, high volume fractions of the particles or high effec-tive viscosity of the liquid favors the engulfment of particles by the melt-interface. Solidification in low gravity seems to deflocculate the SiC particle agglomerates while opposite results are obtained when solidifying under high gravity. Intercellular spacings are found to be higher in low gravity so-lidification as compared to high gravity solidification. These results are discussed in terms of the influence of gravity on various physical phenomena involved in the solidification process of the above composite. This paper is based on a presentation made in the symposium “Experimental Methods for Microgravity Materials Science Research” presented at the 1988 TMS-AIME Annual Meeting in Phoenix, Arizona, January 25-29, 1988, under the auspices of the ASM/MSD Thermo-dynamic Data Committee and the Material Processing Committee.     

Melt-Processed Ni3Al matrix composites reinforced with TiC particles

TiC-reinforced Ni₃Al metal matrix composites have been investigated. The composites were prepared by in situ precipitation of either 0.01, 0.05, or 0.1 vol fraction TiC in molten Ni3Al. These precipitates are thermodynamically stable in the Ni₃Al at 1000 °C up to 50 hours. Although almost ideal precipitate distribution was achieved at low volume fraction of TiC, at higher volume fraction, there was a tendency toward agglomeration. Room and hightemperature mechanical testing showed significant improvement in modulus, yield strength, and ultimate tensile strength, while still maintaining a 2.5 pct elongation at 0.1 vol. fraction TiC and 500 °C. The density of precipitates (number/m³) is strongly dependent on the fraction of TiC, on temperature, and on the holding time at that temperature. The critical nucleation temperature for these precipitates was determined to be at 1475 °C. Experimentally evaluated growth rate constants indicate a diffusion-controlled coarsening mechanism along with coalescence and multiparticle interaction at higher volume fractions of TiC. This is in accordance with either the Lifshitz Slyozov Encounter Modified (LSEM) model or with the Voorhees and Glicksman (VG) model.     

Ceric ammonium nitrate‐initiated graft copolymerization of acrylamide onto Cassia tora gum

Graft copolymerization of acrylamide onto Cassia tora gum was studied in an aqueous medium using ceric ammonium nitrate‐nitric acid as the redox initiator. To optimize the reaction conditions for obtaining maximum percent grafting, the concentrations of Cassia tora gum, ceric ammonium nitrate, acrylamide, and nitric acid, time, and temperature were varied. Results are discussed and a reaction mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3250–3255, 2002     

Adsorption density of spherical cetyltrimethylammonium bromide (CTAB) micelles at a silica/silicon surface

In situ Fourier transform infrared internal reflection spectroscopy (FT-IR/IRS) was used to calculate the adsorption density values for spherical cetyltrimethylammonium bromide (CTAB) micelles at the silica/silicon (SiO2/Si) surface based on a previously developed adsorption density equation. Recent advances in atomic force microscopy (AFM) imaging methodology have led to the ability to image surface micelles, which was not possible previously. These AFM images have been used to independently calculate adsorption density values through offline fast Fourier transform (FFT) analysis. The adsorption density values measured from in situ FT-IR/IRS spectra and from AFM images showed good agreement and provide further validation of the FT-IR/IRS adsorption density equation in the low concentration range.     

Refugees,Violence and Gender: the Case of Women in the Albert Park Area in Durban,South Africa

Women refugees are affected more by violence than any other female group in the world, before, during and after their forced migration experience, because of patriarchy. This paper examines the violence experienced by female refugees in Albert Park in Durban, South Africa. Albert Park is an area dominated by documented and undocumented foreign migrants from African countries, and since 2008, there have been many reported incidents of violence against refugees. The focus of this study is on intimate partner and public violence, the fear of urban public space and the failure of police protection encountered by female refugees as they have attempted to adapt and adjust in a hostile society, in Albert Park. Domestic tensions have emerged from a reversal of traditional patriarchal gender roles as female refugees have often become heads of households, while men had to tend to domestic chores. Female refugees are also afraid of using public space because they were subject to physical attacks, verbal abuse and sexual harassment from refugees, local people and taxi drivers and conductors. This has been aggravated by the high levels of xenophobic violence in South Africa, tensions between local people and foreigners and the knowledge that police protection is limited.