COMMUNICATION | doi:10.20944/preprints202012.0334.v1
Subject: Computer Science And Mathematics, Other Keywords: scoring opportunity identification; proprioceptive shooting volume; 0 possession shot; airborne; anthropometry
Online: 14 December 2020 (13:12:20 CET)
From a scientific standpoint, both temporal and spatial variables must be examined when developing programs for training various soccer scoring techniques (SSTs), but a review of current literature reveals that existing scientific studies have overlooked this combinatory influence. Consequently, there is no reliable theory on temporal-spatial identification when evaluating scoring opportunities. Quantified by using biomechanical modeling, anthropometry, and SSTs found in FIFA Puskás Award (121 nominated goals between 2009 and 2020), it is found that players’ proprioceptive/effective shooting volume (i.e. players’ attack space) could be sevenfold the currently-practiced shooting volume. The ignorance of some SSTs’ training leads to the underuse of the potential shooting volume. These overlooked SSTs are airborne and/or acrobatic techniques, perceived as high-risk and low-reward. Relying on the talent of an athlete to improvise on the fly can hardly be considered as a viable coaching strategy. Therefore, for developing science-based SST training regimes, groundbreaking studies are needed to: 1) expand the perception of shooting volume, and 2) entrain one-touch-shot techniques (airborne/acrobatic) within this volume, in short, Focusing-on-Time-in-Space. Whence, the new temporal-spatial theory could guide future researches and develop novel training programs. An increase of airborne/acrobatic goals would ultimately further enhance the excitement of the game.
REVIEW | doi:10.20944/preprints201704.0109.v1
Subject: Engineering, Control And Systems Engineering Keywords: fiber ring laser; hybrid mode locking; passive mode locking; rational harmonic mode locking; pulse compression
Online: 18 April 2017 (05:14:55 CEST)
Mode locked pulse generation has been reported using both active and passive mode locking schemes. Active mode locking technique has been proven to be an effective way to generate high-repetition-rate pulses by incorporating a modulator inside the laser cavity. Compared to actively mode locked lasers, passively mode locked lasers can generate pulse train at ultrashort pulse width but with relatively lower repetition rate. Thus, it is a brilliant idea to build a hybrid mode locked system combining both active and passive mode lockers. In this review, several hybrid mode locked fiber ring laser systems are discussed and summarized. Hybrid mode locking is a promising method to generate high speed ultrashort optical pulses for fiber-optic telecommunication system.
ARTICLE | doi:10.20944/preprints202005.0087.v1
Subject: Social Sciences, Behavior Sciences Keywords: 3D motion capture; full-body biomechanical modeling; X-factor; hip flexibility; whip-like movement; dispersion of impact load during falling
Online: 5 May 2020 (16:01:29 CEST)
Jumping side volley has created breathtaking moments and cherished memories for us. Regrettably, a scientific study on the skill has not been found in literature. Relying on talent of athletes to improvise on the fly can hardly be considered a viable learning strategy. This study targets to fill the gap by quantifying factors contributing to develop its coaching method. Using 3D motion capture (12-cameras, 200Hz) and full-body biomechanical modeling, our study aimed to identify elements that govern entrainment of the skill by examining jumping, kicking and falling phases of its execution. Given the rarity of players who have acquired this skill, we found five subjects for the study. Twenty-three trials were captured and quantified. The results unveil the following key elements: 1) the control of trunk rotation during the jumping, 2) the angle between thighs upon take-off, 3) the whip-like control of the kicking leg during airborne, 4) timing between ball motion and limbs’ coordination, and 5) damping mechanism during falling. An accurate kick can only be achieved through repetitive training. This underlines the need for athletes to master a safe landing technique that minimizes risk of injury during practice. Therefore, training should begin with learning a safe falling technique.
ARTICLE | doi:10.20944/preprints202305.2188.v1
Subject: Engineering, Aerospace Engineering Keywords: WAAM; surface waviness; fatigue; bending test; durability; fracture mechanics
Online: 31 May 2023 (07:47:02 CEST)
This paper reports the effect of as-deposited surface condition on the fatigue strength in an additive manufactured titanium alloy Ti-6Al-4V (WAAM Ti64). First, local stress concentration caused by the surface waviness was quantified by a metrology technique followed by numerical modelling. Fatigue tests were conducted under bending load with the as-deposited surface being under tensile cyclic stress. The applicability of two predictive methods was studied and compared with the fatigue test results. The traditional notch stress method overestimated the fatigue strength by a factor of 1.5 at a given life; the poor agreement with the test is attributed to the crack propagation from the waviness being dominant in the bending test, i.e., the crack initiation stage was short, hence the local stress method is unsuitable. The fracture mechanics approach has delivered good predictions at every applied stress levels. The method treats a waviness trough as an initial crack. This approach is suitable for predicting the fatigue life in materials built by wire based directed energy deposition processes.
REVIEW | doi:10.20944/preprints202204.0117.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cold stress; wheat; hormonal; reactive oxygen species; epigenetic regulation
Online: 13 April 2022 (07:35:35 CEST)
Cold stress is a major environmental factor affecting the growth, development, and productivity of various crop species. With the current trajectory of global climate change, low temperatures are becoming more frequent and can significantly decrease crop yield. Wheat (Triticum aestivum L.) is the first crop to be domesticated and is the most popular cereal crop in the world. Due to a lack of systematic research on cold response pathways and gene regulatory networks, the underlying molecular mechanisms of cold signal transduction in wheat are poorly understood. This study reviews recent progress in wheat, including the ICE-CBF-COR signaling pathway in cold stress and the effects of cold stress on hormonal pathways, reactive oxygen species (ROS), and epigenetic regulation. This review also highlights outstanding issues that are crucial for understanding the interactions between wheat and low-temperature conditions.
REVIEW | doi:10.20944/preprints201704.0059.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Keywords: vitamin D deficiency; diabetic retinopathy; meta-analysis.
Online: 11 April 2017 (06:16:22 CEST)
Background: Diabetic retinopathy (DR) is one of the most prominent pathological microvascular complications in diabetes. A series of studies reported that vitamin D deficiency was associated with increased prevalence of retinopathy in diabetic patients but the results were inconsistent. In this study we focused on evaluating the relationship between vitamin D deficiency and DR by conducting a meta-analysis of observational studies. Methods: Systematic computerized searches were performed in PubMed, MEDLINE, and the Cochrane Library for relevant original articles till November 20, 2016. The pooled odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated to assess the associated value of vitamin D deficiency to the risk of DR. 9 studies including 6332 participants were subjected to final analysis. Results: The results indicated that vitamin D deficiency increases the risk of DR (OR = 1.57, 95% CI 1.32-1.87) with a little heterogeneity (I2 = 23%). In addition, the subgroup analysis demonstrated that there were obvious heterogeneities in T2DM (I2 = 47.8%). Sensitivity analysis showed that the results were relatively stable and reliable. Conclusion: our meta-analysis demonstrated that vitamin D deficiency could increase the risk of DR.
ARTICLE | doi:10.20944/preprints202307.0041.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Antibiotics residue; Response Surface Methodology (RSM); Quinolones; Tetracyclines; Multiple Reaction Monitoring (MRM)
Online: 3 July 2023 (09:45:39 CEST)
The present study employed a modifed QuEChERS method to systematically analyze the presence of fifteen Quinolones and seven Tetracyclines antibiotic residues in local animal food. Additionally, a multi-level-four-factor Box-Behnken design (BBD) within the framework of Response surface methodology (RSM) was utilized to evaluate the various factors affecting the detection efficiency of the sample pretreament procedure. The optimization was performed by Design Expert®, the factors including volume of the acetonitrle, the addition of formic acid, the duration of extract and the addition of EDTA were combined to experiment design until reach an optimal solution. Finally, the sample test was conducted by ultra-high performance liquid chromatography-quadrupole-linear ion trap mass spectrometry in both multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan modes on a QTRAP® 5500 instrument. The overall average recoveries from actual samples fortified with 22 antibiotics at three levels ranged from 74.7 to 122.6% based on the use of matrix-fortified calibration with the variation ranging from 2.1 to 18.2% (n=6). The limits of detection and quantification were 0.3 μg kg-1 and 1.0 μg kg-1, respectively.
ARTICLE | doi:10.20944/preprints202304.0205.v1
Subject: Chemistry And Materials Science, Other Keywords: Tungsten; MCNP; Epoxy resin; Gamma rays; shielding
Online: 11 April 2023 (06:09:34 CEST)
With the development of nuclear technology application, radiation safety has been widely concerned, and there is an urgent need for novel shielding materials. Among the various options available, non-lead organic composite shielding material has emerged as a promising solution in the field of radiation shielding due to its high strength, easy processing, and light weight. In this study, tungsten/epoxy resin (W/EP) composite samples with tungsten weight fraction from 0% to 60% were prepared. The shielding and mechanical properties of W/EP composites were investigated. The results show that the results showed that the higher the tungsten content, the greater the shielding capacity of W/EP composites, particularly for low-energy gamma ray (γ) shielding. However, the addition of tungsten reduces the impact strength and tensile properties of the material. Overall, for 300 keV γ-ray, W/EP with 30% tungsten content has comparable shielding capacity to ordinary concrete. W/EP composite materials can serve as shielding materials for low-energy γ-rays.
ARTICLE | doi:10.20944/preprints202305.1806.v1
Subject: Chemistry And Materials Science, Paper, Wood And Textiles Keywords: phenol-formaldehyde resin; soybean meal; soy-based adhesives; curing; plywood
Online: 25 May 2023 (10:55:13 CEST)
To develop a lower-cost, excellent performance, and environmentally friendly phe-nol-formaldehyde (PF) resin, soybean meal was used to modify PF resin, and soybean meal-phenol-formaldehyde (SMPF) resins were prepared. Their physicochemical properties and curing performance were investigated, showing that SMPF resins have higher curing tempera-tures than PF resin. The Fourier transform infrared spectroscopy (FTIR) results indicated that the cross-linking reaction occurred between the amino groups of soybean protein and the hy-droxymethyl phenol. Moreover, with the addition of soybean meal, the viscosity of SMPF in-creased while the gel time decreased. It is worth mentioning that SMPF-2 resin has favorable viscosity, short gel time, low curing temperature (135.78 °C), and high water resistance and bonding strength (1.01 MPa). Finally, all the plywoods bonded with SMPF resins have good water resistance and bonding strength, which could meet the Standard (GB/T 17657-2013, type I) for plywood. The optimized SMPF resins showed the potential application to replace part of PF resin in the wood industry.