In this retrospective study, powerlifting performances in the United States from 1995 – 2005 were taken from annual top 100 rankings published in Powerlifting USA magazine. The rankings included results for the squat, bench press, deadlift, and total for each standard weight class during a calendar year. In the current study, average performances for each weight class were compiled for the #1, #10, #50, and #100 ranks. The weights lifted for each category increased as a function of the competitor’s weight class in a curvilinear pattern, with the heaviest classes showing diminishing improvement in weight lifted with increased body weight. When weights lifted were standardized to the lifter’s weight class, a unimodal curve was observed, with maximal values being in the middle weight classes. The lower mass-specific performance in heavier lifters is the basis for Wilks coefficient and other adjustments for comparing performances among different weight classes. This coefficient is a mathematical formula based on a polynomial transformation of a lifter’s weight class. It was derived to compensate for the curvilinear nature of lifting performance as a function of body weight. Based on the patterns documented, it is proposed that part of this flattening of performance can be attributed to systematic differences in body composition across weight classes. During this 11-year period, significant improvements were observed for some lifts, ranks, and weight classes. However, many did not change, while others showed significant declines. These data demonstrate that U.S. powerlifters at the turn of the century were highly competitive, particularly within the middle through the heaviest weight classes. Overall, the lifting performances in the U.S. during this decade provide an historical reference point, from a time before powerlifting records became more widely available via the internet.
Metal oxide nanoparticles have gained a lot of popularity in recent years because of their broad band gap and several practical uses in solar, catalysis, sensors, actuators, and other domains. This work investigates the effects of Gd ion substitution on structural and electrical transportation properties in co-precipitated ZnO nanostructures. The prepared samples were characterized using XRD, field emission scanning electron microscopy, FT-IR (infrared spectroscopy), PL (photoluminescence), and complex impedance spectroscopy. The XRD data with crystallite size of 29 nm revealed the wurtzite hexagonal structure in space group P63mc. The morphology micrograph shows where the samples have accumulated. For two hours, a photocatalytic reactor was used to measure the photocatalytic degradation of Gd-doped ZnO nanoparticles. Degradation efficiencies (ϳ%) for the ZnO sample doped with Gd are 81 percent.
We are concerned with the numerical solution obtained by splitting methodsof certain parabolic partial differential equations. Splitting schemes of order higher than two with real coefficients necessarily involve negative coefficients. It has been demonstrated that this se cond-order barrier can be overcome by using splitting methods with complex-valued coefficients (with positive real parts). In this way, method s of orders 3 to 14 by using the Suzuki‐Yoshida triple (and quadruple) jump composition procedure have been explicitly built. Here we reconsider this technique an d show that it is inherently bounded to order 14 and clearly sub-optimal with respect to error constants. As an alternative, we solve directly the algebraic equations arising from the order conditions and construct methods of orders 6 and 8 that are the most accurate ones available at present time, even when low accuracies are desired. We also show that, in the general case, 14 is not an order barrier for splitting method s with complex coefficients with positive real part by building explicitly a method of order 16 as a composition of methods of order 8.