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Power Lifting

Changping Liang, Huaxing Li
This paper reports on the optimization of the NACA0015 aerofoil for improving the power performance of a vertical axis wind turbine (VAWT). The target range of the chord Re is 3 × 105 -106 , the tip speed ratio (TSR) is 2-6 and the solidity is 0.2-0.6. This aerofoil is widely applied in small-scale VAWTs. In the optimization process, in which the class and shape function transformation parametrization method was used to perturb the aerofoil geometry, the thickness and camber of the aerofoil were selected as the constraints and the value of the maximum tangential force coefficient was chosen as the objective function...
July 2018: Royal Society Open Science
Franz Konstantin Fuss
The principles of slipstreaming or drafting are very well known in muscle-powered sports, but unknown in gravity-powered sports. Typical examples of gravity-powered sports, where several athletes are racing against each other, are ski-cross and snowboard-cross. The aim of this research is to investigate the effectiveness and practical applicability of slipstreaming in ski-cross. A glide model consisting of leading and trailing skiers was developed and used with existing aerodynamic drag and lift data sets from wind tunnel tests...
2018: Frontiers in Physiology
Scott Waitukaitis, Kirsten Harth, Martin van Hecke
The Leidenfrost effect occurs when a liquid or stiff sublimable solid near a hot surface creates enough vapor beneath it to lift itself up and float. In contrast, vaporizable soft solids, e.g., hydrogels, have been shown to exhibit persistent bouncing-the elastic Leidenfrost effect. By carefully lowering hydrogel spheres towards a hot surface, we discover that they are also capable of floating. The bounce-to-float transition is controlled by the approach velocity and temperature, analogously to the "dynamic Leidenfrost effect...
July 27, 2018: Physical Review Letters
Lloyd Renals, Jason Lake, Justin Keogh, Kieran Austin
Renals, L, Lake, J, Keogh, J, and Austin, K. Strongman log push press: The effect log diameter has on force-time characteristics. J Strength Cond Res XX(X): 000-000, 2018-Strongman training is becoming more common in strength and conditioning practices, particularly the log press. The existing literature analyzes force characteristics of the log clean and jerk or press compared with the weightlifting clean and jerk exercise. This investigation aims to explore the braking and propulsive phase performance characteristics of the push press with a barbell and strongman logs of different sizes...
July 26, 2018: Journal of Strength and Conditioning Research
Masaki Andoh, Satoshi Mikami, Shuichi Tsuda, Tadayoshi Yoshida, Norihiro Matsuda, Kimiaki Saito
As part of the investigation of the distribution of ambient dose equivalent rates around the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), car-borne surveys using Kyoto University RAdiation MApping (KURAMA) systems have been conducted over a wide area in eastern Japan since 2011. The enormous volume of measurement data collected until 2016, including those until 2012 which were reported in the previous paper, was analyzed, and dependencies of the decreasing trend of the dose rates in regions within 80 km of the FDNPP on land-use categories, evacuation order areas and magnitude of the dose rates were examined...
July 23, 2018: Journal of Environmental Radioactivity
Alexander T Carswell, Samuel J Oliver, Laurel M Wentz, Daniel S Kashi, Ross Roberts, Jonathan C Y Tang, Rachel M Izard, Sarah Jackson, Donald Allan, Lesley E Rhodes, William D Fraser, Julie P Greeves, Neil P Walsh
PURPOSE: To determine the relationship between vitamin D status and exercise performance in a large, prospective cohort study of young men and women across seasons (Study-1). Then, in a randomized, placebo-controlled trial, to investigate the effects on exercise performance of achieving vitamin D sufficiency (serum 25(OH)D ≥ 50 nmol·L) by a unique comparison of safe, simulated-sunlight and oral vitamin D3 supplementation in wintertime (Study-2). METHODS: In Study-1, we determined 25(OH)D relationship with exercise performance in 967 military recruits...
July 30, 2018: Medicine and Science in Sports and Exercise
M J Dadswell, A D Spares, M F Mclean, P J Harris, R A Rulifson
Tidal hydroelectric power has been proposed as one potential solution for sustainable energy sources. The first tidal turbine in North America began continuous operation in the Annapolis River estuary (44o 45' N; 65o 29' W) in June, 1985. The machine is an axial-flow, hydraulic-lift propeller turbine, a type known to cause fish mortality. Anadromous populations of American shad Alosa sapidissima, striped bass Morone saxatilis and Atlantic sturgeon Acipenser oxyrinchus utilize the Annapolis River for spawning and other life history phases...
July 25, 2018: Journal of Fish Biology
Carrie Scheel, Jim Mecham, Vic Zuccarello, Ryan Mattes
BACKGROUND: OccuPro's functional capacity evaluation (FCE) is used for assessing the client's readiness to return to work and three separate intra-rater and inter-rater reliability studies are explored here. OBJECTIVE: Three separate studies were conducted on injured and un-injured adults to evaluate the inter-rater and intra-rater reliability of the OccuPro FCE (upper extremity and material handling subtests). All three studies are summarized in this publication...
2018: Work: a Journal of Prevention, Assessment, and Rehabilitation
Stergios Mavromatis, Alexandra Laiou, George Yannis
An existing vehicle dynamics model was utilized to define design parameters up to which steady state cornering conditions apply and consequently lift the restrictions of the point mass model. Aiming to assess critical safety concerns in terms of vehicle skidding, the motion of a passenger car was examined over a range of design speed values paired with control design elements from AASHTO 2011 Design Guidelines as well as certain values of poor pavement friction coefficients. Two distinct cases were investigated; the determination of the maximum attainable constant speed (termed as safe speed) at impending skid conditions as well as the case of comfortable curve negotiation where lower constant speed values were utilized...
July 20, 2018: Accident; Analysis and Prevention
August G Domel, Gino Domel, James C Weaver, Mehdi Saadat, Katia Bertoldi, George V Lauder
Biomechanists and biologists alike have yet to fully understand the complex morphology and function of shark denticles, morphologically intricate tooth-like structures embedded into the skin of sharks. Denticles vary in many ways (such as size and shape) depending on shark species, and studies on denticle hydrodynamics have suggested that they may aid in drag reduction as well as increase both lift and thrust. Although previous studies have analyzed the effect of different denticle patterns on hydrodynamic performance, no previous work has focused on the effects of denticle size...
August 2, 2018: Bioinspiration & Biomimetics
Lance M Bollinger, Jason T Brantley, Justin K Tarlton, Paul A Baker, Rebekah F Seay, Mark G Abel
Bollinger, LM, Brantley, JT, Tarlton, JK, Baker, PA, Seay, RF, and Abel, MG. Construct validity, test-retest reliability, and repeatability of performance variables using a flywheel resistance training device. J Strength Cond Res XX(X): 000-000, 2018-Power production is highly associated with physical performance; however, the ability to quantitatively measure power output during resistance exercise is lacking. The purpose of this study was to determine the validity and test-retest reliability of flywheel-based performance testing...
July 9, 2018: Journal of Strength and Conditioning Research
Chong Shen, Yanpeng Liu, Mao Sun
We measured the wing kinematics of fruitflies in both vertically-ascending and hovering flights and studied the aerodynamic forces and power in the two flight modes. The average ascending velocity is 0.45 m s-1 ; the stroke plane angle and the stroke frequency are the same as that in hovering flight, whilst the stroke amplitude is increased by 12% and the wing angle of attack in the latter half of a down- and upstroke both increased by 10%. Flow analysis shows that during ascending, the flies experience a downward inflow which reduces the effective angle of attack considerably...
July 31, 2018: Bioinspiration & Biomimetics
Nidia Lauzon, Pierre Chaurand
For over one hundred years, the fingerprint has reigned as one of the most trusted pieces of forensic evidence for suspect identification. In the last few decades, the modernization of chemical analysis technologies led scientists to explore new possibilities to further analyse fingermarks sampled from a crime scene. Indeed, the detection of chemicals a suspect has been in contact with before or during the crime can provide valuable insights into criminal investigations. In this regard, imaging mass spectrometry (IMS) has shown to be a powerful tool for the analysis of fingermarks by combining suspect identification and the detection of numerous endogenous and exogenous compounds...
July 23, 2018: Analyst
Corey M Peak, Amy Wesolowski, Elisabeth Zu Erbach-Schoenberg, Andrew J Tatem, Erik Wetter, Xin Lu, Daniel Power, Elaine Weidman-Grunewald, Sergio Ramos, Simon Moritz, Caroline O Buckee, Linus Bengtsson
Background: Travel restrictions were implementeded on an unprecedented scale in 2015 in Sierra Leone to contain and eliminate Ebola virus disease. However, the impact of epidemic travel restrictions on mobility itself remains difficult to measure with traditional methods. New 'big data' approaches using mobile phone data can provide, in near real-time, the type of information needed to guide and evaluate control measures. Methods: We analysed anonymous mobile phone call detail records (CDRs) from a leading operator in Sierra Leone between 20 March and 1 July in 2015...
June 26, 2018: International Journal of Epidemiology
John Davenport, Natasha D Phillips, Elizabeth Cotter, Lawrence E Eagling, Jonathan D R Houghton
Adult ocean sunfish are the heaviest living teleosts. They have no axial musculature or caudal fin. Propulsion is by unpaired dorsal and anal fins; a pseudocaudal fin ('clavus') acts as a rudder. Despite common perception, young sunfish are active predators that swim quickly, beating their vertical fins in unison to generate lift-based propulsion and attain cruising speeds similar to salmon and marlin. Here we show that the thick subcutaneous layer (or 'capsule'), already known to provide positive buoyancy, is also crucial to locomotion...
June 21, 2018: Journal of Anatomy
Anthony Caterisano, Randolph Hutchison, Clarence Parker, Scott James, Stephen Opskar
Caterisano, A, Hutchison, R, Parker, C, James, S, and Opskar, S. Improved functional power over a 5-week period: Comparison of combined weight training with flexible barbell training. J Strength Cond Res 32(8): 2109-2115, 2018-Previous studies demonstrated increased power development with various resistance-training modes over short training periods of 4-7 weeks through neuromuscular adaptations. The purpose of this study was to compare 2 different power-training regimens over a 5-week period: combined weight training program (CT) using speed-lifts and plyometrics vs...
August 2018: Journal of Strength and Conditioning Research
Greg Ongie, Mathews Jacob
Fourier domain structured low-rank matrix priors are emerging as powerful alternatives to traditional image recovery methods such as total variation (TV) and wavelet regularization. These priors specify that a convolutional structured matrix, i.e., Toeplitz, Hankel, or their multi-level generalizations, built from Fourier data of the image should be low-rank. The main challenge in applying these schemes to large-scale problems is the computational complexity and memory demand resulting from a lifting the image data to a large scale matrix...
December 2017: IEEE Transactions on Computational Imaging
Jason Lake, Freddie Duncan, Matt Jackson, David Naworynsky
This study compared typical mechanical variables of interest obtained directly from barbell motion during deadlift performance with a conventional (CBD) and a hexagonal barbell (HBD). Eleven men, proficient with both deadlift variations, volunteered to participate in the study (age: 20.3 ± 0.6 years; height: 175.5 ± 8.5 m; mass: 88.7 ± 19.0 kg; CBD 1RM: 183 ± 22 kg; HBD 1RM: 194 ± 20 kg). During the first session, CBD and HBD 1RM was assessed; during the second session, they performed 3 sets of 1 CBD repetition with 90% 1RM; and in session three, they repeated this process with the HBD...
October 24, 2017: Sports
Robert G Lockie, Samuel J Callaghan, Matthew R Moreno, Fabrice G Risso, Tricia M Liu, Alyssa A Stage, Samantha A Birmingham-Babauta, John J Stokes, Dominic V Giuliano, Adrina Lazar, DeShaun L Davis, Ashley J Orjalo
The close-grip bench press (CGBP) is a variation of the traditional bench press (TBP) that uses a narrower grip (~95% of biacromial distance (BAD)) and has potential application for athletes performing explosive arm actions from positions where the hands are held close to the torso. Limited research has investigated CGBP mechanics compared to the TBP. Twenty-seven resistance-trained individuals completed a one-repetition maximum TBP and CGBP. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% BAD...
June 24, 2017: Sports
Takao K Hensch, Elizabeth M Quinlan
The shift in ocular dominance (OD) of binocular neurons induced by monocular deprivation is the canonical model of synaptic plasticity confined to a postnatal critical period. Developmental constraints on this plasticity not only lend stability to the mature visual cortical circuitry but also impede the ability to recover from amblyopia beyond an early window. Advances with mouse models utilizing the power of molecular, genetic, and imaging tools are beginning to unravel the circuit, cellular, and molecular mechanisms controlling the onset and closure of the critical periods of plasticity in the primary visual cortex (V1)...
January 2018: Visual Neuroscience
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