1,031 research outputs found

    Methodology to Measure the Protective Areal Density of Ceramic Tiles Against Projectile Impact

    Get PDF
    The protective areal density of any armour material is the important property required for armour design. In this study, ballistic performance of hot pressed boron carbide tiles, with a tile thickness of 12.2 mm, was evaluated using the protective areal density (PAD) test method, against hard steel 12.7 mm armour piercing (AP) projectiles. The binary response data on complete penetration/ partial penetration obtained from PAD testing was fitted with the standard logistic regression model. A detailed discussion on statistical procedure has been presented. The PAD (pp = 0.5) was estimated to be 82.5 kg/m2 and the lower and upper bounds of 95 per cent confidence interval for (PAD) (pp = 0.5) was found to lie between 79.5 kg/m2 and 85.0 kg/m2

    Functional outcome of patients undergoing open rotator cuff repair

    Get PDF
    Background: Rotator cuff tears are a common source of shoulder pain. The incidence of rotator cuff damage increases with age and is most frequently due to degeneration of the tendon rather than injury from sports or trauma. Rotator cuff tear can be treated arthroscopically, arthroscopically assisted (mini-open) or by an open procedure. Because of the technical demands of arthroscopic repair many surgeons consider open repair for the treatment of rotator cuff tears. This study was done to evaluate the functional outcome of shoulder after open rotator cuff repair.Methods: 26 patients with partial and complete rotator cuff tears underwent open rotator cuff repair and acromioplasty. Cases were followed up at 3 months and 6 months intervals and shoulder function was assessed using Constant-Murley scoring system and compared with the preoperative scores and analyzed using SPSS software.Results: Mean preoperative constant score was 33.95±7.545 while the mean constant score at 6 months post-surgery was 79.83±8.51 which was highly significant according to paired t test. The difference between preoperative, 3 months and 6 months constant scores of complete and partial tear patients was found to be statistically significant.Conclusions: There was highly significant increase in Constant-Murley score after 6 months in patients treated by open rotator cuff repair. Open repair still stands as an effective treatment for rotator cuff tears and doing acromioplasty during the procedure adds to better outcome after surgery

    Comparison of experimental and numerical sloshing loads in partially filled tanks

    Get PDF
    Sloshing phenomenon consists in the movement of liquids inside partially filled tanks, whichgenerates dynamic loads on the tank structure. Resulting impact pressures are of great importance in assessingstructural strength, and their correct evaluation still represents a challenge for the designer due to the highnonlinearities involved, with complex free surface deformations, violent impact phenomena and influence of airtrapping. In the present paper a set of two-dimensional cases for which experimental results are available areconsidered to assess merits and shortcomings of different numerical methods for sloshing evaluation, namely twocommercial RANS solvers (FLOW-3D and LS-DYNA), and two own developed methods (Smoothed ParticleHydrodynamics and RANS). Impact pressures at different critical locations and global moment induced by watermotion for a partially filled tank with rectangular section having a rolling motion have been evaluated and resultsare compared with experiments

    Ballistic Performance of Alumina and Zirconia-toughened Alumina Against 7.62 Armour Piercing Projectile

    Get PDF
    A study was carried out to compare the ballistic performance of high purity alumina and zirconia-toughened alumina (ZTA) using depth of penetration (DoP) test configuration against 7.62 mm armour piercing (AP) ammunition. The effect of tile thickness on the differential efficiency factor (DEF) was studied for tile thickness in the range of 3 mm to 6 mm for alumina tiles and 3 mm to 5 mm for ZTA tiles. The DEF is found to increase as tile thickness increases. An analysis on the failed shots showed that the residual shot weight does not follow a single linear relationship with ceramic tile thickness unlike the residual DoP for all thicknesses of tiles. Post-ballistic analysis on ceramic powder for particle size distribution was carried out and the results are presented.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.477-483, DOI:http://dx.doi.org/10.14429/dsj.64.674

    A lower bound for interval routing in general networks

    Get PDF
    Includes bibliographical references (p. 11).At head of title: Computer science publication.Cover title.published_or_final_versio

    Economic benefits of metrology in manufacturing

    Get PDF
    In streamlined manufacturing systems, the added value of inspection activities is often questioned, and metrology in particular is sometimes considered only as an avoidable expense. Documented quantification of economic benefits of metrology is generally not available. This work presents concrete examples from industrial production, in which the added value of metrology in manufacturing is discussed and quantified. Case studies include: general manufacturing, forging, machining, and related metrology. The focus of the paper is on the improved effectiveness of metrology when used at product and process design stages, as well as on the improved accuracy and efficiency of manufacturing through better measuring equipment and process chains with integrated metrology for process control

    Nanoscale magnetic field mapping with a single spin scanning probe magnetometer

    Get PDF
    We demonstrate quantitative magnetic field mapping with nanoscale resolution, by applying a lock-in technique on the electron spin resonance frequency of a single nitrogen-vacancy defect placed at the apex of an atomic force microscope tip. In addition, we report an all-optical magnetic imaging technique which is sensitive to large off-axis magnetic fields, thus extending the operation range of diamond-based magnetometry. Both techniques are illustrated by using a magnetic hard disk as a test sample. Owing to the non-perturbing and quantitative nature of the magnetic probe, this work should open up numerous perspectives in nanomagnetism and spintronics

    Hydrogen induced optically-active defects in silicon photonic nanocavities

    Get PDF
    This work was supported by Era-NET NanoSci LECSIN project coordinated by F. Priolo, by the Italian Ministry of University and Research, FIRB contract No. RBAP06L4S5 and by the EPSRC UKSp project. Partial financial support by the Norwegian Research Council is also acknowledged.We demonstrate intense room temperature photoluminescence (PL) from optically active hydrogen- related defects incorporated into crystalline silicon. Hydrogen was incorporated into the device layer of a silicon on insulator (SOI) wafer by two methods: hydrogen plasma treatment and ion implantation. The room temperature PL spectra show two broad PL bands centered at 1300 and 1500 nm wavelengths: the first one relates to implanted defects while the other band mainly relates to the plasma treatment. Structural characterization reveals the presence of nanometric platelets and bubbles and we attribute different features of the emission spectrum to the presence of these different kind of defects. The emission is further enhanced by introducing defects into photonic crystal (PhC) nanocavities. Transmission electron microscopy analyses revealed that the isotropicity of plasma treatment causes the formation of a higher defects density around the whole cavity compared to the ion implantation technique, while ion implantation creates a lower density of defects embedded in the Si layer, resulting in a higher PL enhancement. These results further increase the understanding of the nature of optically active hydrogen defects and their relation with the observed photoluminescence, which will ultimately lead to the development of intense and tunable crystalline silicon light sources at room temperature.Publisher PDFPeer reviewe
    • …
    corecore