KINEMATIC, KINETIC AND ELECTROMYOGRAPHIC CHARACTERISTICS OF THE SPRINTING STRIDE OF TOP FEMALE SPRINTERS

The main purpose of this study was to find those kinematic, kinetic and electromyographic parameters of the sprinting stride that most affect maximal velocity of top female sprinters. A 20 m flying start test was made with a sample of four female sprinters of the Slovene National team. In addition to maximal velocity, nine kinetic parameters in the contact phase of the sprinting stride were measured. It was found that the most important generators of maximal velocity are: duration of contact phase, duration of braking phase, minimal braking impulse, maximal impulse in propulsion phase, preserving maximal horizontal velocity of CG in braking phase and maximal grabbing velocity of the foot in the forward contact phase. In light of the EMG activation, m. biceps femoris is one of the most important muscles in the sprint

COMPARISON OF ISOMETRIC AND DYNAMIC METHODS OF STRENGTH TRAINING PROGRAM

The purpose of this study was to determine the difference in the quality of muscle strength employing two methods of strength training (isometric, dynamic). Nineteen male university students volunteered to participate in the experiment, encompassing a five week strength training sessions. The dynamic method was applied to the elbow flexion and extension of the right side (load totalling 60 % of maximal performance) and the isometric method applied on the same muscle groups of the left side (maximal voluntary isometric contraction). Pre- and post-test measurements included maximal isometric strength, the angle a expressed the speed of increasing muscle strength and the number of repetitions performed for each exercise (at a of load 60 % max), as a measure of muscle endurance. No differences were found between the results of strength training when using both methods (isometric, dynamic). A five week training program improved the isometric force by about 8-14 % of pre-test values, and by about 34-54 % in repetition exercises with the load. No differences were exhibited in the rate of the speed of increasing muscle strength

Numerical Prediction of Cavitating Vortex Rope in a Draft Tube of a Francis Turbine with Standard and Calibrated Cavitation Model

Transient simulations of flow in a Francis turbine were performed with a goal to predict pressure pulsation frequencies and amplitudes caused by rotating vortex rope at part load operating regime. Simulations were done with the SAS SST turbulence model with curvature correction on basic and refined computational meshes. Without cavitation modelling too small values of frequency and amplitudes were obtained. With mesh refinement the calculated amplitudes were a bit closer to the measured values, while the accuracy of predicted frequency did not improve at all. Agreement between measured and numerical values was significantly improved when cavitation was included in simulations. In addition, the predicted value of the dominant frequency was slightly more accurate when, in the Zwart et al. cavitation model, the default condensation and evaporation model constants were replaced with previously calibrated ones

EFFECT OF POWDERY MILDEW (Erysiphe graminis D.C. f.sp. tritici Marchal) ATTACK ON YIELD AND PHISICAL PARAMETERS OF WHEAT (Triticum aestivum ssp. vulgare) GRAIN QUALITY

U Križevcima (46001\u27 N – 16032\u27 E), tijekom tri godine (1999-2001.), na 25 divergentnih genotipova pšenice izvršena su ispitivanja rodnosti i pokazatelja fizikalne kakvoće zrna netretiranih (T0) i fungicidom (Duett) tretiranih (T1) varijanata.Ovisno o intenzitetu napada bolesti, prosječni urod zrna za sve tri godine ispitivanja i 25 genotipova u netretranih varijanata bio je manji za 8,1%, prosječna hektolitarska masa za 1,2%, a prosječna masa 1000 zrna za 5,1%. Prosječno umanjenje vrijednosti za 3 godine kod najosjetljivije sorte Marija iznosilo je: 20,8% za urod, 2,6% za hektolitarsku masu i 13,1% za masu 1000 zrna. U godinama jakog napada pepelnice, to umanjenje kod osjetljive sorte Marije iznosilo je: 36,4% za urod (1999.), 3,8% za hektolitarsku masu (2001.) i 20,2% za masu 1000 zrna (2001.). Kod na pepelnicu otpornog genotipa KS92WGRC21 prosječne razlike za ispitana svojstva nisu bile statistički značajne (0,7%, 0,5% i 0,2%).Evaluation of yield and phisical grain quality parameters of fungicidaly (Duett) treated and nontreated variants were taken in Krizevci during the three years (1999-2001) on 25 divergent wheat genotypes. Depending on the intensity of attack, the average grain yield in the three year testing period and 25 genotypes of nontreted variants decreased by 8.1%, the average hectolitre weight decreased by 1.2% and the average TKW by 5.1%. The average decrease of the most sensitive cultivar (Marija) was 20.8% for yield, 2.6% for hectolitre weight and 13.1% for TKW. During a strong attack of powdery mildew this decrease for the most sensitive cultivar was 36.4% for yield in 1999, 3.8% for hectoliter weight in 2001, and 20.2% for TKW in 2001. Average differences were nonsignificant for the tested properties in the completely resistant genotype KS92WGRC21 (0.7%, 0.5 and 0.2% respectively)

Subcell Operation and Long Term Stability Analysis of Perovskite Based Tandem Solar Cells Using a Bichromatic Light Emitting Diode Light Source

In monolithic tandem solar cells, current voltage J V characteristics of subcells provide invaluable information about their quality and tandem operation. However, accessing the subcell J Vs is challenging and requires sophisticated spectral methods. Herein, a customized, bichromatic light emitting diode setup BCLED for in depth analysis of tandem solar cells, suitable for subcell operation analysis, and long term stability testing is presented. For this, two spectrally independent LED arrays are used to selectively bias the two subcells. The power of the developed setup is demonstrated by successfully disentangling the tandem J V curve into subcell J V curves. The method is based on a one diode model for each subcell and is validated by electrical simulations. Afterward, it is used on a fabricated 27.6 efficient perovskite silicon tandem device, resulting in great agreement with the measured J V curve. Therefore, the BCLED setup is a versatile tool, suitable for subcell characteristics and long term stability analysis of tandem solar cell

Proton Radiation Hardness of Perovskite Tandem Photovoltaics.

Monolithic [Cs0.05(MA0. 17FA0. 83)0.95]Pb(I0.83Br0.17)3/Cu(In,Ga)Se2 (perovskite/CIGS) tandem solar cells promise high performance and can be processed on flexible substrates, enabling cost-efficient and ultra-lightweight space photovoltaics with power-to-weight and power-to-cost ratios surpassing those of state-of-the-art III-V semiconductor-based multijunctions. However, to become a viable space technology, the full tandem stack must withstand the harsh radiation environments in space. Here, we design tailored operando and ex situ measurements to show that perovskite/CIGS cells retain over 85% of their initial efficiency even after 68 MeV proton irradiation at a dose of 2 × 1012 p+/cm2. We use photoluminescence microscopy to show that the local quasi-Fermi-level splitting of the perovskite top cell is unaffected. We identify that the efficiency losses arise primarily from increased recombination in the CIGS bottom cell and the nickel-oxide-based recombination contact. These results are corroborated by measurements of monolithic perovskite/silicon-heterojunction cells, which severely degrade to 1% of their initial efficiency due to radiation-induced recombination centers in silicon.F.L. acknowledges financial support from the Alexander von Humboldt Foundation via the Feodor Lynen program and thanks Prof. Sir R. Friend for supporting his Fellowship at the Cavendish Laboratory. This work was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (HYPERION, grant agreement number 756962). M.J, A.A.A., E.K., and S.A. acknowledge financial support from the German Federal Ministry of Education and Research (BMBF) via program “Materialforschung für die Energiewende” (grant no. 03SF0540), by the German Federal Ministry for Economic Affairs and Energy (BMWi) through the ‘PersiST’ project (Grant No. 0324037C). T.B. C.A.K. and R.S. acknowledge funding by BMWi through the speedCIGS (grant no. 0324095E) and EFFCIS project (grant no. 0324076D). D.K. and M.C. acknowledge financial support from the Dutch Ministry of Economic Affairs, via The Top-consortia Knowledge and Innovation (TKI) Program ‘‘Photovoltaic modules based on a p-i-n stack, manufactured on a roll-to-roll line featuring high efficiency, stability and strong market perspective’’ (PVPRESS) (TEUE118010) and “Bridging the voltage gap” (BRIGHT) (1721101). K. F. acknowledges the George and Lilian Schiff Fund, the Engineering and Physical Sciences Research Council (EPSRC), the Winton Sustainability Fellowship, and the Cambridge Trust for funding. S.D.S. acknowledges the Royal Society and Tata Group (UF150033). The authors acknowledge the EPSRC for funding (EP/R023980/1). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 841265. A.R.B. acknowledges funding from a Winton Studentship, Oppenheimer Studentship, and funding from the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Centre in Photovoltaics (CDT-PV). K.G. acknowledges the Polish Ministry of Science and Higher Education within the Mobilnosc Plus program (Grant No. 1603/MOB/V/2017/0)

CsxFA1 xPb I1 yBry 3 Perovskite Compositions the Appearance of Wrinkled Morphology and its Impact on Solar Cell Performance

We report on the formation of wrinkle patterned surface morphologies in cesium formamidinium based CsxFA1 amp; 8722;xPb I1 amp; 8722;yBry 3 perovskite compositions with x 0 amp; 8722;0.3 and y 0 amp; 8722;0.3 under various spin coating conditions. By varying the Cs and Br contents, the perovskite precursor solution concentration and the spin coating procedure, the occurrence and characteristics of the wrinkle shaped morphology can be tailored systematically. Cs0.17FA0.83Pb I0.83Br0.17 3 perovskite layers were analyzed regarding their surface roughness, microscopic structure, local and overall composition, and optoelectronic properties. Application of these films in p amp; 8722;i amp; 8722;n perovskite solar cells PSCs with indium doped tin oxide NiOx perovskite C60 bathocu proine Cu architecture resulted in up to 15.3 and 17.0 power conversion efficiency for the flat and wrinkled morphology, respectively. Interestingly, we find slightly red shifted photoluminescence PL peaks for wrinkled areas and we are able to directly correlate surface topography with PL peak mapping. This is attributed to differences in the local grain size, whereas there is no indication for compositional demixing in the films. We show that the perovskite composition, crystallization kinetics, and layer thickness strongly influence the formation of wrinkles which is proposed to be related to the release of compressive strain during perovskite crystallization. Our work helps us to better understand film formation and to further improve the efficiency of PSCs with widely used mixed perovskite composition