316 research outputs found

    Use of orthogonal or parallel plating techniques to treat distal humerus fractures.

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    Distal humerus fractures continue to be a complex fracture to treat. This article describes two surgical techniques that can be used to tackle these difficult fractures: Parallel plating and orthogonal plating. Both techniques have yielded excellent outcomes after open reduction and internal fixation; yet each has its own set of unique considerations. However, the key to successful treatment of these difficult fractures regardless of technique remains obtaining anatomic reduction with stable fixation and the implementation of early motion

    Analysis and Optimization of Machining Process Parameters Using Design of Experiments

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    In any machining process, apart from obtaining the accurate dimensions, achieving a good surface quality and maximized metal removal are also of utmost importance. A machining process involves many process parameters which directly or indirectly influence the surface roughness and metal removal rate of the product in common. Surface roughness and metal removal in turning process are varied due to various parameters of which feed, speed, depth of cut are important ones. A precise knowledge of these optimum parameters would facilitate reduce the machining costs and improve product quality. Extensive study has been conducted in the past to optimize the process parameters in any machining process to have the best product. Current investigation on turning process is a Response Surface Methodology applied on the most effective process parameters i.e. feed, cutting speed and depth of cut while machining Aluminium alloy and resin as the two types of work pieces with HSS cutting tool. The main effects (independent parameters), quadratic effects (square of the independent variables), and interaction effects of the variables have been considered separately to build best subset of the model. Three levels of the feed, three levels of speed, three values of the depth of cut, two different types of work materials have been used to generate a total 20 readings in a single set. After having the data from the experiments, the performance measures surface roughness (Ra) of the test samples was taken on a profilometer and MRR is calculated using the existing formulae. To analyze the data set, statistical tool DESIGN EXPERT-8 (Software) has been used to reduce the manipulation and help to arrive at proper improvement plan of the Manufacturing process & Techniques. Hypothesis testing was also done to check the goodness of fit of the data. A comparison between the observed and predicted data was made, which shows a close relationship. Key words: Surface Roughness and Metal Removal Rate, Turning, Response Surface    Methodology, Aluminium Alloy, Resin.

    Characterization of the first hexacoordinate phosphorus compound with S→P←S bonds

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    The first example of a hexacoordinate phosphorus compound [S{6-t-Bu-4-Me-C6H2O}2]2P+(Cl-· C3H4N2) with two S→P bonds is reported. This compound can be construed as an oxophosphonium salt with double intramolecular coordination by sulfur atoms. X-ray structure reveals a facial arrangement of the ligands with two coordinating sulfur atoms cis to each other. The S→P distance of 2.334 (1) Å is one among very short coordinate bond distances between sulfur and phosphorus

    Effect of Disorder and Notches on Crack Roughness

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    We analyze the effect of disorder and notches on crack roughness in two dimensions. Our simulation results based on large system sizes and extensive statistical sampling indicate that the crack surface exhibits a universal local roughness of ζloc=0.71\zeta_{loc} = 0.71 and is independent of the initial notch size and disorder in breaking thresholds. The global roughness exponent scales as ζ=0.87\zeta = 0.87 and is also independent of material disorder. Furthermore, we note that the statistical distribution of crack profile height fluctuations is also independent of material disorder and is described by a Gaussian distribution, albeit deviations are observed in the tails.Comment: 6 pages, 6 figure

    Design of multiligand inhibitors for the swine flu H1N1 neuraminidase binding site

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    Viral neuraminidase inhibitors such as oseltamivir and zanamivir prevent early virus multiplication by blocking sialic acid cleavage on host cells. These drugs are effective for the treatment of a variety of influenza subtypes, including swine flu (H1N1). The binding site for these drugs is well established and they were designed based on computational docking studies. We show here that some common natural products have moderate inhibitory activity for H1N1 neuraminidase under docking studies. Significantly, docking studies using AutoDock for biligand and triligand forms of these compounds (camphor, menthol, and methyl salicylate linked via methylene bridges) indicate that they may bind in combination with high affinity to the H1N1 neuraminidase active site. These results also indicate that chemically linked biligands and triligands of these natural products could provide a new class of drug leads for the prevention and treatment of influenza. This study also highlights the need for a multiligand docking algorithm to understand better the mode of action of natural products, wherein multiple active ingredients are present

    Size effects in statistical fracture

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    We review statistical theories and numerical methods employed to consider the sample size dependence of the failure strength distribution of disordered materials. We first overview the analytical predictions of extreme value statistics and fiber bundle models and discuss their limitations. Next, we review energetic and geometric approaches to fracture size effects for specimens with a flaw. Finally, we overview the numerical simulations of lattice models and compare with theoretical models.Comment: review article 19 pages, 5 figure

    An Efficient Block Circulant Preconditioner For Simulating Fracture Using Large Fuse Networks

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    {\it Critical slowing down} associated with the iterative solvers close to the critical point often hinders large-scale numerical simulation of fracture using discrete lattice networks. This paper presents a block circlant preconditioner for iterative solvers for the simulation of progressive fracture in disordered, quasi-brittle materials using large discrete lattice networks. The average computational cost of the present alorithm per iteration is O(rslogs)+delopsO(rs log s) + delops, where the stiffness matrix A{\bf A} is partioned into rr-by-rr blocks such that each block is an ss-by-ss matrix, and delopsdelops represents the operational count associated with solving a block-diagonal matrix with rr-by-rr dense matrix blocks. This algorithm using the block circulant preconditioner is faster than the Fourier accelerated preconditioned conjugate gradient (PCG) algorithm, and alleviates the {\it critical slowing down} that is especially severe close to the critical point. Numerical results using random resistor networks substantiate the efficiency of the present algorithm.Comment: 16 pages including 2 figure

    Rare occurrence of sunfish Mola mola (Linnaeus) from the coastal waters off Visakhapatnam (Bay of Bengal)

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    The occurrence of sunfish in any sea is a rare event. It is so rare that even fishermen engaged in fishing throughout their lives find it totally strange when they come across one. On 6 May, 1986, a local fisherman reported to the Zoology Department of the Andhra University that a very strange looking fish was part of that day's catch

    Mechanical characterization of microwave sintered zinc oxide

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    The mechanical characterization of microwave sintered zinc oxide disks is reported. The microwave sintering was done with a specially designed applicator placed in a domestic microwave oven operating at a frequency of 2.45 GHz to a maximum power output of 800 Watt, These samples with a wide variation of density and hence, of open pore volume percentage, were characterized in terms of its elastic modulus determination by ultrasonic time of flight measurement using a 15 MHz transducer, In addition, the load dependence of the microhardness was examined for the range of loads 0.1-20 N, Finally, the fracture toughness data (K-IC) was obtained using the indentation techniqu
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