Free Ball Research Articles

Application of Free Ball Check Valve Mixed Grouting Device

In recent years, due to the uneven water abundance of the aquifer and the complexity of the underground seepage field, the grouting reconstruction project of coal mining enterprises is more difficult. The previous method is to install a high-pressure ball valve before the grouting pipe connected to the grouting pump is connected to the mixing device, which can be manually adjusted when the number of grouting pumps needs to be changed. However, under certain pressure, the ordinary high-pressure ball valve often fails due to the influence of high-pressure mixed slurry, cement solidification and wear, and the number of grouting pumps cannot be increased or decreased in real time. In order to solve the problem that the mixing device of traditional grouting system is easy to fail by using ordinary high-pressure ball valve, the mixing device of free ball check valve was developed and applied in the process of treating the Ordovician limestone aquifer area on the floor of No.9 coal seam in Xipang Well. The practical results show that the pipeline can be automatically closed when a single grouting pump stops grouting, and there is no need to flush the grouting pipeline with a large amount of water, which can improve the grouting efficiency and quality, and the influence time of single hole section is reduced from 8.25h to 0.34h. The process performance can meet the requirements of efficient grouting.

Big Bang Theory

Abstract In 1927 a Belgian cosmologist and a catholic priest George Lemaitre proposed the Big Bang Theory. It explains about what happen for Bang that occurred 13.8 billion years ago. The Big Bang is how astronomers explain the way the universe began. Researches say that universe is still expanding. What causes the acceleration? Big Bang theory explains it. The earliest times of the universe lasting from approximately 10-43 to 10-11seconds after the Big Bang. According to Big Bang Theory all matter in the universe were concentrated as single extremely dense and hot free ball. Scientists like Stephen Hawking, George Elis and Roger Penrose have studied and researched on the Big Bang Theory. Big Bang hypothesis states that “All of the current and past matter in the universe came into existence at the same time”.

Mathematical Method to Construct Linear Programming Scheme of Football Training

Abstract Linear programming is a widely applicable mathematical operation method. In this paper, two solutions of linear programming and state parameter extraction can be used to simplify the inequality group and transfer the high-dimensional state utility function in football. This can speed up the generation of joint strategies for football teams in the game. This paper uses the free-kick technical football cooperation as an example to conduct an empirical study on the linear programming method of state parameters. In this paper, combined with the traditional motion information modeling method, a free ball path planning based on the linear programming gradient method is established. At the same time, this paper adopts an asymptotic method based on linear programming to solve the trajectory of any football. Finally, an experimental study on the linear programming gradient method for state feature vectorization is carried out. Experiments verify the effectiveness of this method. The mathematical model accurately predicts the linear programming of football training.

Abrasive Wear Resistance of High-Strength Compacted Graphite Iron under Microabrasion Conditions

Compacted graphite iron (CGI) has been considered an excellent option for heavy-duty engine blocks due to its superior mechanical properties, which allow reduction of weight, enhancing engine performance. Abrasion is a recognized wear mechanism in engine blocks, meaning it deserves to be evaluated for CGI. This study analyzed two grades of high-strength CGI (GJV450 and GJV500) submitted to microscale abrasion tests in free ball configuration using two different slurries: diamond and silica. There was more wear to the surfaces tested with silica due to the particle size, which was one order of magnitude larger than the diamond. The data obtained showed that both materials presented similar resistance when tests were performed with the diamond slurry. On the other hand, when silica was used, GJV500 presented 2.5 times greater wear resistance than GJV450, even though its global hardness was only 17% greater.

Influence of the situational variables on the performance of the teams competing in the Chinese Super League

ABSTRACT The aim of this study was to assess the impact of situational variables, match location, quality of the opponent, and final result on the performance of the teams during an entire season (2016) of the Chinese Super League throughout 474 matches. Results showed that playing as an away team reduced the number of positional attacks per game, total ball possession time, possession in the final third of the field, possession in opponent half, passes attempted, passes accurate, crosses, passes forward, picking up free balls, and picking up free balls in opponent half. Final result only affected total attacks made per game and lost ball by the teams that finished the season between the 8th and the 16th position. These teams made an average of 99.29 attacks per game, which was lowered by 1.53 attacks for each goal that the team had in comparison with the opponent at the end of the match. In addition, number of lost balls was also reduced by 1.49 per game for each goal that one team had in comparison with the opponent at the end of the match. Overall, combinations of these variables could be used in order to predict the performance of soccer teams.

Automatic discrete failure study of cage free ball bearings based on variable diameter contact

Automatic discrete failure study of cage free ball bearings based on variable diameter contact

A case of left atrial free ball thrombus in a patient with prosthetic mitral valve.

A free left atrial ball thrombus is relatively a rare diagnosis and usually leads to systemic embolization or fatal complication of thrombus incarceration in left ventricle inflow. We report a case of 52-year-old woman who was admitted to hospital with symptoms of heart failure. Routine echocardiography showed a free-floating ball thrombus in the left atrium. The free-floating thrombus was round with smooth surface and about 37 mm in diameter. The mitral valve prosthesis was well-functioning. The computed tomography of the patient also showed the left atrial ball thrombus. The erratic finding was that the patient was compliant on oral anticoagulants for the last 6 months with her INR in theraputic range. This suggested that this thrombus had been there for a some time and anticoagulants failed to resolve this problem. She was referred to cardiac surgery for thrombus extraction but the patient refused to have the operation.

ZnO/biochar nanocomposites via solvent free ball milling for enhanced adsorption and photocatalytic degradation of methylene blue

There are challenges in developing multifunctional materials that can not only effectively adsorb but also completely eliminate organic contaminants in water. In this work, novel ZnO/biochar nanocomposites were synthesized using a facile ball-milling method. A series of characterization results showed that the ZnO nanoparticles dispersed uniformly on carbon surface within the biochar matrix. Ball milling increased the mesopores and macropores of the nanocomposites by breaking biochar and squeezing ZnO. The addition of appropriate amount of ZnO into biochar enhanced both the adsorption capacity and photocatalytic ability of the nanocomposites for methylene blue (MB) removal. When the initial concentration of MB was 160 mg/g, the nanocomposites exhibited high MB removal efficiency (up to 95.19%) under visible light through the combination of adsorption and photocatalysis. This work provides a feasible synthesis of metal oxide/biochar nanocomposites with excellent adsorption and photocatalysis properties for the treatment of organic dye wastewater.

Axial direction behavior observation of the free side ball bearing installed by loose fit

Axial direction behavior observation of the free side ball bearing installed by loose fit

Color Tunable Self-Trapped Emissions from Lead-Free All Inorganic IA-IB Bimetallic Halides Cs-Ag-X (X = Cl, Br, I).

Multi-metallic halides of group IA and IB metals are emerged as a new class of color tunable emitters. While chalcogenides and perovskites are extensively studied, these families of materials are little explored. In comparison, herein, lead and cadmium free bimetallic Cs-Ag-X (X = Cl, Br, I) halides are reported where the larger ion Ag+ helped in incorporating all the halide ions which in turn tune their emission color in spanning from 397nm (violet) to 820nm (near infrared) as a function of their composition. The synthesis method adopted here is the solvent free ball milling of respective halides of Cs and Ag and took the record shortest time and in bulk scale. From decay lifetimes, emissions from these bimetallic halides are found as a result of fast recombination of self-trapped excitons, which exhibited not only reasonably high quantum yield in the range of 17-68% but also excellent stability to air and moisture under ambient conditions. These also show wide Stokes shift with relatively longer decay lifetimes ranging above the exciton and below the surface trap or dopant induced emissions of inorganic semiconductors, indicating a new class of materials having unique identity of their optical behaviors.

Match Situations Leading to Head Injuries in Professional Male Football (Soccer)-A Video-Based Analysis Over 12 Years.

To identify risk situations promoting head injuries in professional male football (soccer) and to investigate the impact of a rule change in 2006 punishing elbow-head contacts. Analysis of video sequences of head events leading to head injury. Professional football players of the first male German Bundesliga. Observational criteria of head impacts on video recordings (players' actions preceding head injuries, foul play-referee's decision and assessment of rater, ball possession, on-pitch medical treatment, and consequences of head impact). Three hundred thirty-four head injuries were reported in kicker Sportmagazin corresponding to an incidence rate of 2.25 (95% confidence interval 2.01-2.51) per 1000 player match hours. The injured player predominantly jumped (60%), headed the ball (36%), or ran forwards (20%); the noninjured players mainly jumped (64%), headed the ball (27%), or raised the elbow to the head (23%). Free ball situations (2 players challenge for the ball) caused most of the head injuries (81%). The players' action "raising the elbow" during a head injury seemed to be lower after the rule change. Jumping for the ball with the intention of heading is the predominant action associated with head injury risk. Head injuries occur most often when players challenge for the ball in a header duel. As head injuries bear the potential risk of long-term health sequelae, the identification of situational circumstances is essential to develop preventative means in the future.

The Effect of Imagery Training on The Improvement of Basketball Game Free Throw Skills in Basketball Extracurricular Students of SMA Negeri 8 Surakarta

<h1><em>The aim of the eyeball research was to see that there was no effect of image on improving skills in playing free ball games in basketball extracurricular students at SMA Negeri 8 Surakarta in 2019/2020. This research is a quasi-experimental study with a pretest and posttest control group design. By giving treatment (treatment) to the experimental group, by dividing into two groups with ordinal pairing, namely the experimental group with imagery training treatment and the control group using the free throw training treatment. The population in this study were all basketball extracurricular students at SMA Negeri 8 Surakarta for the 2019/2020 school year, totaling 24 students. Data collection techniques norms <sup>and</sup> documentation. The data analysis technique uses descriptive statistical techniques with the help of the IBM SPSS 22 program. The results showed that there was a significant effect of imagery training on the improvement of free throw basketball skills for basketball extracurricular students at SMA Negeri 8 Surakarta It shows that the pre-test average score is 6.75 with the highest score of 12, after being given the imagery training treatment the value increases by an average of 9.00 with the highest score of 14, the percentage of skill improvement is 33%. The results of this study can be concluded that imagery training can effectively improve the free throw skills of basketball games for extracurricular students at SMA Negeri 8 Surakarta for the 2019/2020 school year.</em></h1>

Algebras of free holomorphic functions and localizations

We consider the algebras of holomorphic functions on a free polydisc , and the algebra of holomorphic functions on a free ball . We show that the algebra is a localization of a free algebra and, moreover, is a free analytic algebra with generators (in the sense of J. Taylor), while the algebra is not a localization of a free algebra. In addition we prove that the class of localizations of free algebras and the class of free analytic algebras are closed under the operation of the Arens-Michael free product. Bibliography: 21 titles.

Micro-abrasive wear resistance of the duplex expanded austenite layer phases produced by plasma nitrocarburizing

The present study investigates the influence of the phases of the duplex expanded austenite layer on the micro-abrasive wear resistance of the plasma nitrocarburized AISI 304 austenitic stainless steel. Plasma nitrocarburizing was performed by using a gaseous atmosphere containing 80% N2 + 2% CH4 + 18% H2, producing precipitate-free duplex expanded austenite layers (γN+γC) at 375 °C and 430 °C, composite layer (γN+γC + Fe3N-ε + CrN) at 475 °C and nitride layer (Fe4N-γ’ + CrN) at 555 °C. Each phase of duplex expanded austenite layer was produced in separate gaseous atmospheres at 375 °C, carbon expanded austenite monolayer (γC) in 2% CH4 + 98% H2 and nitrogen expanded austenite monolayer (γN) in 80% N2 + 20% H2. The abrasive wear behavior was measured in a free ball micro-scale abrasion tester with fine-particle abrasive slurry of SiO2 which allowed to evaluate wear resistance and wear mechanism of the produced layers. The results showed that the thicker duplex expanded austenite layer which was precipitate-free (γN+γC), produced at 430 °C, displayed the highest wear resistance. From analyses of the individual monolayers, two wear mechanisms were found: two-body abrasion related to the nitrogen-rich phase (γN) and three-body abrasion associated to the carbon-rich phase (γC).

Does efficiency of service after the 20th scores in volleyball differ according to nationality and positions? <p>Voleybolda 20. sayılar sonrası atılan servis etkinliği uyruk ve mevkilere göre değişiklik gösterir mi?

The first technique that starts the match in volleyball is service. It has been known that benefiting efficiently from the service as the first hitting attack in each period of the match is remarkable. However, it has also been emphasized in the study carried out by Marcelino et al. that managing the scores especially at the end of the set and match are more important for the trainers and players. For that reason, it is considered that trainers’ including target-specific service work-outs in training programs will be the most remarkable factor for winning the game (Marcelino, Sampaio et al., 2012)The purpose of this study was to examine the change of service efficiency after the 20th scores according to nationality and positions in 2017-2018 Volleyball Sultanlar League session. Into the study, totally 134 female players including natives (n=94) and foreigners (n=40) from 12 teams between 26 and 30 years old (28.25±1,62) were included. The numbers of the services performed after the 20th scores of 17.918 rallies in 496 sets (except from the 5th set) of 125 matches played by 12 teams during the session were evaluated. All matches were recorded with a video recorder by the researcher, and the videos were analyzed by the experts in 3 repetitions. The service error, service as the free ball, bad service, good service, service ace and total number of service after the 20th scores during the match were recorded in numbers. Lilliefors Kolmogorov-Smirnov Test indicated whether the study data were appropriate for the normal distribution or not (p<.05). In data analysis, descriptive statistics such as number, percentage, arithmetic average and standard deviation were used; and Independent Samples T-Test and One-Way Variance Analysis (One-Way ANOVA) were used for determining the difference between dependent and independent variables. While interpreting the data, 0.01 and 0.05 were accepted as the level of significance. The research data were analyzed using SPSS 21 statistical software.As result of the findings obtained at the end of the study, it was determined that there were significant differences except from the service as the free ball in terms of the Turkish players and foreign-national players (p<0.05). No significant difference was noticed in terms of service error, service as the free ball, bad service, good service, service ace and total number of service after the 20th scores during the session depending upon the positions of the players (p>.05). As a result, it is determined that foreign players serve more effectively than native players at 20th points which is named as golden points.Extended English summary is in the end of Full Text PDF (TURKISH) file.ÖzetVoleybolda müsabakayı başlatan ilk teknik servistir. İlk hücum vuruşu olan servisi müsabakanın her periyodunda etkin kullanmanın önemli olduğu bilinmektedir. Ancak özellikle setin ve maçın son bölümlerindeki sayıların yönetiminin antrenörler ve sporcular için daha önemli olduğu Marcelino ve arkadaşlarının yapmış olduğu çalışmada da vurgulanmıştır. Bu nedenle antrenörler antrenman programlarında hedefe yönelik etkin servis çalışmalarına yer vererek maçı kazanmada en önemli etken olacağı düşünülmektedir (Marcelino, Sampaio et al. 2012)Bu çalışmanın amacı, 2017-2018 voleybol Süper lig sezonunda 20. sayılar sonrası atılan servis etkinliğinin uyruk ve mevkilere göre değişikliğinin incelenmesidir. Çalışmaya 26-30 yaş arası (28.25±1,62) 12 takımdan yerli (n=94), yabancı (n=40) toplam 134 kadın oyuncu dahil edilmiştir. Sezon içerisinde 12 takımın mücadele ettiği 125 maç da (5. set hariç) 496 set 17.918 rallinin 20. sayılar sonrası atılan servis sayıları değerlendirilmiştir. Bütün maçlar araştırmacı tarafından video kamera ile kayıt altına alınmış, videolar uzman kişiler tarafından 3 tekrar ile analiz edilmiştir. Müsabaka esnasındaki 20. sayılardan sonra yaptıkları servis hatası, avantaj top olarak dönen servis, kötü servis, iyi servis, servis ace ile toplam servis sayıları adet cinsinden kaydedilmiştir. Değişkenlerin normal dağılıma uygunluğu Lilliefors Kolmogorov-Smirnov testi çalışma verilerinin normal dağılıma uygun olmadığını göstermiştir (p<.05). Verilerin analizinde; tanımlayıcı istatistikler (sayı, yüzde, aritmetik ortalama ve standart sapma) ile bağımlı ve bağımsız değişkenler arasındaki farklılığı saptamak amacıyla; Bağımsız Gruplar için t Testi ve Tek Yönlü Varyans Analizi (One-Way-Anova) kullanılmıştır. Verilerin yorumlanmasında 0.01 ve 0.05 anlamlılık düzeyi kullanılmıştır. Araştırma verileri SPSS 21 programı ile analiz edilmiştir. Elde edilen bulgular sonucunda; Türk sporcular ile yabancı uyruklu sporcuların avantaj olarak dönen servis sayıları hariç anlamlı farklar tespit edilmiştir (p>.05). Sonuç olarak; yabancı uyruklu sporcuların, altın sayılar olarak da adlandırılan 20. Sayılarıda, yerli oyunculardan daha etkin servis attığı belirlenmiştir.

Wear resistance of the pressure armor submitted to deep cryogenic treatment and plasma nitriding

Risers are multilayer structures used in oil production and transportation. The pressure armor is the layer responsible for supporting the internal radial pressure and is produced from a helical interlocked steel wire. The interlocking mechanism, which gives flexibility to the riser, is responsible for the wear on the pressure armor, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear in the pressure armor. Samples tested were taken from the contact region of the pressure armor. The micro-abrasive wear test was performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 h). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient similar to the sample as received. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received and an improvement in wear coefficient in the transient (29.85%, 28.53% and 29.81%) and permanent (19.18%, 25.19% and 28.09%) regions.

On fixed points of self maps of the free ball

In this paper, we study the structure of the fixed point sets of noncommutative self maps of the free ball. We show that for such a map that fixes the origin the fixed point set on every level is the intersection of the ball with a linear subspace. We provide an application for the completely isometric isomorphism problem of multiplier algebras of noncommutative complete Pick spaces.

Influence of ultrasonic sound on physico-mechanical characteristics of titanium alloys

The paper presents data on the influence of ultrasonic vibrations on the main physico-mechanical characteristics in the hardening of titanium alloys. Hardening was carried out during rolling and using free balls in a special working chamber with the imposition of ultrasonic vibrations. The studies have shown that ultrasonic hardening of titanium alloys promotes crushing blocks of mosaic and the formation of a fine-grain structure with a high density of dislocations, changes the phase composition of the surface layer and causes the formation of compressive residual stresses. At the same time, technological heredity is practically not manifested. The endurance range of titanium alloys increases.

Reaction of PdCl2 with Diphenylacetylene Revisited: Effect of Solvents and Ball Milling on Cyclization and Crystal Structures of Dimeric Cyclobutenylpalladium Chloride Complexes

AbstractIn an attempt to establish the structures of the product formed in the reaction of PdCl2 and diphenylacetylene in polar organic solvents, the reactions were carried out in alcohols, acetonitrile and tetrahydrofuran at room temperature. The reactions in protic solvents such as primary and secondary alcohols resulted in the cyclic dimerization of diphenylacetylene to yield the corresponding dimeric endo‐4‐alkoxy‐π‐1,2,3,4‐tetraphenylcyclobutenypalladium(II) chloride complexes 1–4 in good yields. In these complexes the tetraphenylcyclobutenyl moieties are coordinated to palladium atoms in η3‐mode and are bridged by two chlorides as confirmed by the single crystal X‐ray analysis of complexes 1, 2 and 4. In all these complexes, the coordination of cyclobutenyl moieties to palladium atoms are similar but a marked difference was observed for the Pd2Cl2 core which is planar in complex 1 but puckered in complexes 2 and 4 resulting in shorter Pd⋅⋅⋅Pd distances. The same reaction under solvent free ball milling condition yielded hexaphenylbenzene by the cyclic trimerization while that in the presence of ethanol and n‐butanol produced complexes 1 and 3, respectively, as major and hexaphenylbenzene as minor product. An efficient catalytic synthesis of hexaphenylbenzene using PdCl2 was developed using ball milling condition which has several advantages over the existing catalytic systems.

Styles of play in professional soccer: an approach of the Chinese Soccer Super League

Describing and measuring different styles of play that soccer teams can adopt during a match is a very important step towards a more predictive and prescriptive performance analysis. The current study aimed to identify and measure different styles of play in professional soccer. The sample comprises all 240 matches in the Chinese Soccer Super League during the 2016 season. Data were examined using a linear regression analysis and a factor analysis. Five factors had eigenvalues greater than 1 and explained 79.6% of the total variance. The following styles of play were found: Factor 1 (“possession” style of play, correlated with the ball possession, ball possession in opponent half and in the final third of the field, positional attacks, passes, accurate passes, passes forward and back), Factor 2 (set pieces attack, correlated positively with the number of set pieces attacks, and attacks), Factor 3 (counterattacking play, correlated with interceptions, interceptions in opponents half, recovered balls, and number of counterattacks) and Factor 4 and 5 (transitional play, correlated with lost balls, and picking up free balls). These metrics may allow coaches and analysts to classify the teams’ into specific profiles of playing styles.