RESPONSE CHARACTERISTICS OF A SQUAT - AND COUNTERMOVEMENT JUMP

NI

THE VARIABILITY OF VERTICAL GROUND REACTION FORCES DURING UNLOADED AND LOADED DROP JUMPING

The increase of the resistance of the movement - on the basis of the dynamic fundamental law F.t = m.v (Force Impulse = Change of the Kinematic Impulse) - can be achieved either by increasing the drop velocity v (initial height of the drop jump) or by increasing the body mass m of the athlete (adding a weighted vest). The purpose of this study was to investigate the behavior of the forcetime parameters of the force impulse by varying the kinematic impulse, using unloaded and loaded drop jumping. METHOD Ten top track & field and diving athletes (6 male and 4 female) participated in this study, 17-24 years old. The subjects were instructed to perform three unloaded drop jumps from heights (drop velocities) of 0.30 m (2.43 d s ) , 0.45m (2.97 d s ) , 0.55m (3.28 d s ) and two loaded drop jumps from a standard height of 0.30m (2.434s) where the additional load was defined based on the Kinematic impulses that arise from the unloaded drop jumps the height of 0.45m and 0.55111 respectively. A Kistler fore platform was used to record the force-time curves of the jumps. RESULTS AND DISCUSSION The calculated values of the average vertical jumped distances for the unloaded conditions (drop height 0.45m,0.55m), as it was expected, were found to be 20% and 31% higher in comparison to the loaded drop jumps respectively. The results of the analysis of the variability in the force-time parameters have shown no significant differences (p>.05, student's t-test at .05 level) for the total average force (acceleration force and loaded force) between unloaded and loaded jumps while for the acceleration force significant differences (

Hybrid redox flow cells with enhanced electrochemical performance via binderless and electrophoretically deposited nitrogen-doped graphene on carbon paper electrodes.

Hybrid redox flow cells (HRFC) are key enablers for the development of reliable large-scale energy storage systems; however, their high cost, limited cycle performance, and incompatibilities associated with the commonly used carbon-based electrodes undermine HRFC's commercial viability. While this is often linked to lack of suitable electrocatalytic materials capable of coping with HRFC electrode processes, the combinatory use of nanocarbon additives and carbon paper electrodes holds new promise. Here, by coupling electrophoretically deposited nitrogen-doped graphene (N-G) with carbon electrodes, their surprisingly beneficial effects on three types of HRFCs, namely, hydrogen/vanadium (RHVFC), hydrogen/manganese (RHMnFC), and polysulfide/air (S-Air), are revealed. RHVFCs offer efficiencies over 70% at a current density of 150 mA cm-2 and an energy density of 45 Wh L-1 at 50 mA cm-2, while RHMnFCs achieve a 30% increase in energy efficiency (at 100 mA cm-2). The S-Air cell records an exchange current density of 4.4 × 10-2 mA cm-2, a 3-fold improvement of kinetics compared to the bare carbon paper electrode. We also present cost of storage at system level compared to the standard all-vanadium redox flow batteries. These figures-of-merit can incentivize the design, optimization, and adoption of high-performance HRFCs for successful grid-scale or renewable energy storage market penetration

Evaluation of a non-aqueous vanadium redox flow battery using a deep eutectic solvent and graphene-modified carbon electrodes via electrophoretic deposition

Common issues aqueous-based vanadium redox flow batteries (VRFBs) face include low cell voltage due to water electrolysis side reactions and highly corrosive and environmentally unfriendly electrolytes (3 to 5 M sulfuric acid). Therefore, this investigation looks into the comparison of a highly conductive ionic liquid with a well-studied deep eutectic solvent (DES) as electrolytes for non-aqueous VRFBs. The latter solvent gives 50% higher efficiency and capacity utilization than the former. These figures of merit increase by 10% when nitrogen-doped graphene (N-G)-modified carbon papers, via a one-step binder-free electrophoretic deposition process, are used as electrodes. X-ray computed tomography confirms the enhancement of electrochemical surface area of the carbon electrodes due to N-G while electrochemical impedance spectra show the effect of its higher conductivity on improving RFB performance. Finally, potential strategies for the scaling-up of DES-based VRFBs using a simple economical model are also briefly discussed. From this study, it is deduced that more investigations on applying DESs as non-aqueous electrolytes to replace the commonly used acetonitrile may be a positive step forward because DESs are not only cheaper but also safer to handle, far less toxic, non-flammable, and less volatile than acetonitrile

The Hellenic type of nondeletional hereditary persistence of fetal hemoglobin results from a novel mutation (g.-109G>T) in the HBG2 gene promoter

Nondeletional hereditary persistence of fetal hemoglobin (nd-HPFH), a rare hereditary condition resulting in elevated levels of fetal hemoglobin (Hb F) in adults, is associated with promoter mutations in the human fetal globin (HBG1 and HBG2) genes. In this paper, we report a novel type of nd-HPFH due to a HBG2 gene promoter mutation (HBG2:g.-109G>T). This mutation, located at the 3′ end of the HBG2 distal CCAAT box, was initially identified in an adult female subject of Central Greek origin and results in elevated Hb F levels (4.1%) and significantly increased Gγ-globin chain production (79.2%). Family studies and DNA analysis revealed that the HBG2:g.-109G>T mutation is also found in the family members in compound heterozygosity with the HBG2:g.-158C>T single nucleotide polymorphism or the silent HBB:g.-101C>T β-thalassemia mutation, resulting in the latter case in significantly elevated Hb F levels (14.3%). Electrophoretic mobility shift analysis revealed that the HBG2:g.-109G>T mutation abolishes a transcription factor binding site, consistent with previous observations using DNA footprinting analysis, suggesting that guanine at position HBG2/1:g.-109 is critical for NF-E3 binding. These data suggest that the HBG2:g-109G>T mutation has a functional role in increasing HBG2 transcription and is responsible for the HPFH phenotype observed in our index cases

Study Desing and Technical-financial analysis of an aggregates production unit

74 σ.Σκοπός της διπλωματικής αυτής εργασίας ήταν ο σχεδιασμός και η οικονομική ανάλυση μιας μονάδας παραγωγής αδρανών υλικών. Η παγκόσμια και η εγχώρια παραγωγή τους είναι σημαντική. Τα αδρανή χρησιμοποιούνται κατά κύριο λόγο σε τεχνικά έργα έχουν όμως και άλλες εφαρμογές. Αρχικά, αναλύονται η διαδικασία και οι μέθοδοι παραγωγής των αδρανών υλικών. Στη συνέχεια μελετάται και σχεδιάζεται μονάδα παραγωγής αδρανών υλικών, συγκεκριμένης δυναμικότητας, από την ανατίναξη και την εξόρυξη, μέχρι και την παραγωγή των προϊόντων με συγκεκριμένη κοκκομετρία. Τέλος, αναλύονται τα οικονομικά μεγέθη μιας μονάδας παραγωγής αδρανών υλικών. Μελετώνται και λαμβάνονται υπόψη όλες οι οικονομικές παράμετροι για την εγκατάσταση, τη λειτουργία μιας μονάδας παραγωγής αδρανών υλικών, τη μελέτη σκοπιμότητας και τα κεφάλαια της επένδυσης μέχρι το αναλυτικό κόστος λειτουργίας της μονάδας παραγωγής.The aim of this thesis was to study the financial analysis of an aggregates production unit. It’s global and national production is of major importance. The aggregates are mainly used in technical constructions but they have other uses too. Firstly, the production and methods of production of aggregates materials are analysed. In addition, this thesis deals with the study and the design of an aggregate production unit, with the specifications (from the blasting and mining) to the production of various products having a specific particle size distribution. Finally, this thesis analyses the financial dimension of an aggregates production plant (design, construction-erection, operation). All the financial issues for the construction and the operation of an aggregates production plant, from the study of each purpose and the capital of investement to the analysis of the operating cost of the aggregate production unit, are extensively studied and taken into consideration.Eυάγγελος Α. Καλαμάρα