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72 results for “Np-hardness”
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Research ArticleOpen accessIn the abstractSTUDY OF PHYSICO-CHEMICAL PROPERTIES OF THE SURFACE AND GROUND WATERA.Y. Al-Ghamdi, Mohamed El-Shahate Ismaiel Saraya, A.O. Al-Ghamdi, S.A. ZabinOf all the natural resources, water is unarguably the most essential and precious. Life began in water and life is nurtured by water. Ninety seven percent of the world’s water is found in oceans. Only 2.5% of the world’s water are non-saline fresh water. Saudi Arabia is a desert country with no permanent rivers or lakes and very little rainfall. … …American Journal of Environmental Sciences, Vol. 10, Issue 3 · 18 Apr 2014 · 7,787 accessesView PDFCite
Research ArticleOpen accessIn the abstractTHE STRUCTURE AND MECHANICAL PROPERTIES OF ALUMINA FILM PREPARED BY RF DIODE SPUTTERINGH. Panitchakan, P. LimsuwanAlumina (Al2O3) films were prepared on Al2O3-TiC substrates by RF diode sputtering. The target sputtering power was varied from 4 to 8 kW. The effects of target sputtering power on the structure and mechanical properties of alumina films were investigated. The results show that the structure of the alumina films deposited at all the target sputtering powers is amorphous. However, … …Physics International, Vol. 4, Issue 1 · 17 Jul 2013 · 6,897 accessesView PDFCite
Research ArticleOpen accessIn the abstractStructural and Dielectrical Properties of Sterilized Human TeethMostafa Fawzy Eissa, Hassan Mohamed El-Shamy, Hassan Saad HanafyProblem statement: This study investigated the changes in crystallinity and dielectrical properties (conductivity) that could be demonstrated in extracted human teeth (enamel and dentin) subjected to γ-radiation at the sterilization dose (25 kGy). Approach: Twenty human third molar teeth were used in the study. Teeth were prepared so forty enamel and dentin samples were obtained. The samples were divided into … …Physics International, Vol. 3, Issue 1 · 20 Dec 2012 · 7,182 accessesView PDFCite
Research ArticleOpen accessIn the abstractMachining Performance Study on Metal Matrix Composites-A Response Surface Methodology ApproachA. Srinivasan, R. M. Arunachalam, S. Ramesh, J. S. SenthilkumaarProblem statement: Metal Matrix Composites (MMC) have become a leading material among composite materials and in particular, particle reinforced aluminum MMCs have received considerable attention due to their excellent engineering properties. These materials are known as the difficult-to-machine materials because of the hardness and abrasive nature of reinforcement element-like Alumina (Al2O3). Approach: In this study, an attempt has been made … …American Journal of Applied Sciences, Vol. 9, Issue 4 · 15 Feb 2012 · 8,017 accessesView PDFCite
Research ArticleOpen accessIn the abstractDistribution, Arrangement and Interconnectedness of Cell Surface Receptor sites in the body of an OrganismUtoh-Nedosa, Uchechukwu AnastasiaCell surface receptors have been identified as the sites of disease infectivity in living organisms in a previous study. Drugs used for the treatment or cure of infections have to eliminate infections through attacking infective organisms at the cell surface receptors to which the infective organisms are attached. Problem statement: The present study examines a wide sample of living things … …OnLine Journal of Biological Sciences, Vol. 11, Issue 4 · 26 Jan 2012 · 7,355 accessesView PDFCite
Research ArticleOpen accessIn the abstractThe Ultra-Precision Polishing of Large Aperture Reaction Bonded Silicon Carbide MirrorYong Shu, Yifan Dai, Ziwen Zheng, Shengyi LiProblem statement: Silicon Carbide (SiC) optical materials have become the first choice for mirrors in space optical systems and large ground-based optical systems due to their outstanding mechanical, physical and optical properties. Compared with traditional optical glasses, SiC optical materials are provided with the characteristics of high hardness and multiphase, which embarrass the high efficient fabrication of SiC mirrors with … …Current Research in Nanotechnology, Vol. 1, Issue 2 · 21 Jun 2011 · 10,815 accessesView PDFCite
Research ArticleOpen accessIn the abstractPreparation and Polishing Properties of Spherical Porous Silica AbrasiveHong Lei, Hu Li, Ping Liu, Ruling ChenProblem statement: Abrasive is one of key influencing factors on the polished surface quality in Chemical Mechanical Polishing (CMP). Solid abrasives in CMP slurries are easy to cause polishing scratches. It is well known that reducing the hardness of abrasives would improve the polished surface quality. Therefore, the change in structure or shape of the abrasives means a change in … …Current Research in Nanotechnology, Vol. 1, Issue 1 · 15 Jun 2011 · 9,285 accessesView PDFCite
Research ArticleOpen accessIn the abstractPositron Annihilation Study on Nickel and Iron Nano-Particles in Natural Rubber CompositesEmad Hassan AlyProblem statement: The effect of Ni and Fe nano-particles as a filler on the free volume properties Of Natural Rubber (NR) was studied using Positron Annihilation Lifetime Spectroscopy (PALS). Approach: The PAL measurements revealed that the free volume properties are strongly affected by the amount and type of filler. Results: Particularly speaking, the free volume fraction dramatically decreased by increasing … …American Journal of Applied Sciences, Vol. 8, Issue 2 · 28 Feb 2011 · 7,625 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance of Difference Electrode Materials in Electrical Discharge Machining of Tungsten CarbideP. Janmanee, A. MuttamaraProblem statement: Electrical Discharge Machining (EDM) is now a well-established machining option in many industries. Tungsten carbide (WC-Co) is an important tool and die material mainly because of its high hardness, strength, wear resistance and high melting point. Normally, EDM is capable of machining geometrically complex or hard material component, that are precise and difficult to machine. The objective of … …Energy Research Journal, Vol. 1, Issue 2 · 31 Oct 2010 · 8,871 accessesView PDFCite
Research ArticleOpen accessIn the abstractA Study of Parameters Relationship to Backcutting Phenomena During High Speed End Milling of AISI H13Erry Yulian T. Adesta, Afifah Mohd Ali, Delvis Agusman et al.Problem statement: In die and mold industries, surface roughness of the dies and molds produced will determine the end product quality. Therefore, the desired finish surface was specified and the appropriate processes were selected to reach the required quality. Among many contributors to surface quality problem, backcutting is one of the factors influencing the surface roughness. Approach: The aim for … …American Journal of Applied Sciences, Vol. 7, Issue 10 · 31 Oct 2010 · 7,509 accessesView PDFCite