Ball Machine Research Articles

Study of Micro-Abrasive Wear Resistance of Heat Treated NiTi Alloys

The Nickel Titanium (NiTi) alloy is a shape memory alloy. It presents two distinct properties: shape memory effect (martensite phase at room temperature) and the pseudoelasticity (austenite phase at room temperature). These materials are frequently used in industries like engineering, dentistry, medicine and aeronautics, and for certain applications it is important to know the wear behavior of these alloys.Thus, this study aims to evaluate the micro-abrasive wear behavior of pseudoelastic NiTi alloys at the as received and aged conditions, and compare with results obtained for NiTi alloy with shape memory effect. The aging heat treatment was performed at temperatures of 350, 450, 500 and 600 °C with an isotherm of 30 minutes and subsequent quenching in water. The wear tests were carried out in a free ball machine. After wear testing was observed that the wear coefficient obtained were lower for all treatment temperatures when compared to pseudoelastic NiTi alloy as received, reducing wear by 30 % in case of treatment at 350 °C. The alloy with shape memory effect showed good wear behavior, with a wear coefficient about 14 % less than the untreated pseudoelastic NiTi alloy.

An Analysis of Machine Effectiveness on the Production Line by Using Overall Equipment Effectiveness (OEE) Method Based on Total Productive Maintenance (TPM) Principle (A Study Case of Ball Tea Machine in PT Kabepe Chakra)

Total Productive Maintenance (TPM) is an approach in Preventive Maintenance which can be used by a company to evaluate the effectiveness of the company’s facility. This evaluation is conducted to improve the facility value of Overall Equipment Effectiveness (OEE) and to eliminate the main loss known as The Six Big Losses. TPM is a maintenance approach focusing on the equipment which is suitable to be implemented on the manufacture company and production industries. This research is conducted on the Ball Tea machine in PT Kabepe Chakra which is a production machine to dry tea. The calculation of OEE value is conducted based on the data in January-December 2014, the calculation results show that the OEE value is 59.30897433% and it is still under the World Class standard. The calculation of Six Big Losses shows that the percentage of the most dominant of machine losses is on the Set-Up and Adjustment Loss which is 42.6768183%. The research results can be used to show that the effectiveness of Tea Ball machine still has to be improved by focusing on the most dominant loss elimination.

Obtaining of Modifiers for Reduced Friction by Еsterification of Waste Glycerol from Biodiesel Production and Sylfat 2

The esterification of waste glycerol from biodiesel production (WG) ore pure glycerol (PG) with Sylfat 2 were made by catalyst 3% titanium alcoholate (TiAl) for 3 h at 150°C. The quantity of glycerol in WG and the oleic acid (OA) in Sylfat 2 were made with UV-VIS spectra. There UV-VIS and FTIR spectra were shown. Some quantity of free acids was neutralized with methylamine ore with 25% water solution of NH3 and was given FTIR spectra of obtained products. All investigations for characteristics of these products were made with standard method by four ball machine. From WG ore PG and Sylfat 2 were obtained the valuable friction modifiers, comparable with standard compounds.

Athletic Injury Management Models in Humans: Revisit

Athletic Injury Management Models in Humans: Revisit Objective: A human injury model has been proposed wherein subjects were hit with a free-flight tennis ball. The research suggested that additional dependent variables were needed to validate the model. It was hypothesized that increasing the speed of the ball would result in an injury that would create decreased knee extension range of motion, measurable swelling, and a color difference. Methods: Subjects were randomly assigned which leg was struck with the tennis ball. On the identified leg a posterior thigh bruise was induced via a tennis ball fired from a tennis ball machine at ~40m/sec from 46cm. Digital photographs were taken of the trauma site immediately before and on days 2, 4, 6, 8, and 10 posttrauma and were analyzed with Photoshop. Average pixel values of cyan, magenta, yellow, black, and luminosity were calculated at each time point. These data, average pixel values from each day minus the initial pixel values, were used to calculate the overall color difference. Second, a diagnostic ultrasound image was taken of the same location. The acquired image was used to quantify the distance between the skin and the fascia, this measurement representing changes resulting from superficial swelling. Lastly, passive knee extension range of motion was measured with a goniometer. Repeated measures ANOVA followed by multiple pairwise comparisons determined whether these measurements differed over the 5 time points. Pearson correlation was used to determine any relationship between outcome measures. Alpha set at P ≤ 0.05. Results: All subjects bruised. No color differences (F4, 48=1.878, P=0.130), swelling (F4, 68=0.056, P=2.388), or differences in range of motion (F4, 68=1.842, P=0.131) were observed. Likewise, not significant correlations were present between color difference, swelling, or range of motion. Conclusion: This model results in a bruise. However, diagnostic ultrasound measurements and extension range of motion did little to further validate the model.

Effect of niobium in the phase transformation and corrosion resistance of one austenitic-ferritic stainless steel

Austenitic-ferritic stainless steels containing 0.2% and 0.5% niobium were evaluated with respect to the microstructures, microhardness, pitting potential resistance, electrochemical impedance and wearing tests. Niobium is an alphagenic element and has a great influence on phase transformation of duplex stainless steels. In the present investigation, the samples were annealed at 1050 ºC and aged at 850 ºC to promote the formation of sigma phase. The pitting potential resistance and electrochemical impedance were evaluated in 3.5 % sodium chloride solution. The wear coefficients were calculated by micro-wear tests conducted using a fixed ball machine and aluminum oxide as abrasive. The results show that the niobium content lead to increase on Laves phase formation. This phase, in association with the sigma phase, causes a significant increase in the hardness and wear resistance with a decrease on corrosion resistance of the austenitic-ferritic stainless steels.

Mechanical passive logic module

Nothing from nothing gives simple simile, but something from nothing is an interesting and challenging task. Adolf Lohmann once proposed ‘do nothing machine’ in optics, which only copies input to output. Passive logic module (PALM) is a special type of ‘do nothing machine’ which can converts inputs into one of 16 possible binary outputs. This logic module is not like the conventional irreversible one. It is a simple type of reversible Turing machine. In this manuscript we discussed and demonstrated PALM using mechanical movement of plane mirrors. Also we discussed the theoretical model of micro electro mechanical system (MEMS) based PALM in this manuscript. It may have several valuable properties such as passive operation (no need for nonlinear elements as other logic device require) and modular logic (one device implementing any Boolean logic function with simple internal changes). The result is obtained from the demonstration by only looking up the output. No calculation is required to get the result. Not only that, PALM is a simple type of the famous ‘billiard ball machine’, which also discussed in this manuscript.

The Study on the Wear Characteristics of Flank Lock Type Precision Locknut in the Dynamic Conditions

This study investigated the wear characteristics and anti-loosening characteristics of flank lock type precision locknut in the dynamic percussion vibration test. The experiment was conducted by using horizontal realistic dynamic percussion vibration test machine. The objective is to simulate the loosening condition of the locknut which was assembled in ball screw and machine tool spindle. Through this study, the wear resistance and anti-loosening characteristics of the precision locknut under the dynamic test were investigated by closely observing the roughness, flatness and tooth angle, seat surface and surface morphology before and after the test. The test results were used to calculate axial force ratio and anti-loosening ratio to understand the wear properties and anti-loosening properties of precision locknut under the dynamic conditions.

Performance of Zinc-Difattyalkyldithyocarbamate as Anti-Friction/Anti-Wear Lubricant Additives

Dithyocarbamate is an organosulphur compound that has long been known and widely applied in various fields, including in agriculture and industry. Several variants of synthesized vegetable oil-based Zinc-difattyalkyldithyocarbamate were tested its anti-friction/anti-wear performance on four ball machine using the method of ASTM-D2783. Anti-friction/anti-wear test to six of additive variants of Zinc-difattyalkyldithyocarbamate at doses of 1.2% indicated that all variants of the product has welding point value higher than the lube base oil lubricant HVI 60, and from US Steel 136 standard for Hydraulic lubricants, but only two additive variants of Zinc-bis(lauryl palmityl)dithyocarbamate and Zinc-bis(lauryl oleyl)dithyocarbamate which has a larger load wear index value than the standard, and meet the criteria as an additive extreme pressure according to US steel 136 standard. Zinc-bis(lauryl palmityl)dithyocarbamate is an additive variant with the best performance, meet bi-functional lubricant additives criteria, as anti-friction/anti-wear and antioxidant additive.

Sliding Allows Faster Repositioning during Tennis Specific Movements on Hard Court

Tennis game is nowadays getting faster and players have to show strong defensive skills in order to win points. This implies returning more balls and repositioning very fast to get ready for the next stroke. In order to achieve this speed demand especially on hard court, a few players are able to slide like on clay court. The purpose of this study was to determine whether sliding on hard court allows a faster repositioning during a tennis specific routine. A total of eighteen male, national level tennis players participated in this study. A new concept of shoe (NSh) was developed specifically to allow players to slide on hard court. The subjects were asked to play three series of ten balls sent by a ball machine, once with the new shoe and once with a regular shoe (RSh). They were instructed to move back quickly to the centre of the court between each stroke. The players’ displacements were videotaped (Casio Exilim FH25, Casio, Tokyo, Japan) at 120Hz from a rear-view in order to record the centre of gravity (CG) trajectories. The main results showed that time for repositioning – defined as the time separating ball contact and CG movement direction inversion - was reduced by up to 42% when wearing NSh compared to RSh. This gain of time resulted in a 1.10 m shorter distance covered by the players between the hit of the ball and the repositioning at the centre of the court. These results are suggesting that with Nsh, the players were able to better adjust their body position to play the strokes. Instead of doing multiple little adjustment steps, players did large lunges, slid, and hit the ball in an open stance position, then began the repositioning right after the stroke.

수음실 잔향 시간변화에 따른 바닥충격음레벨 특성 - 잔향실을 중심으로 -

Field measurement method of heavy/soft impact sound pressure level which is regulated in JIS and ISO has been using in Korea, Japan and Canada. It is reported that heavy/soft impact sound pressure level was varied by the sound field condition of receiving room such as sound absorption power and room volume. In this study, it is checked that heavy/soft impact sound pressure level was affected by the receiving sound field condition. Rubber ball and bang machine sound pressure level was measured in the vertically connected reverberation chamber. In oder to check the effect of receiving sound field on heavy/soft impact sound pressure, sound absorption power was changed with polyester sound absorption blankets with air space and glass wool. The reverberation time at 1 kHz band was changed from 10 s to 0.2 s by sound absorption material. Rubber ball sound pressure level measured without sound absorption material was 58 dB in <TEX>$L_{i,Fmax,AW}$</TEX>, but the level was 46 dB with sound absorption treatment. From this result, it is confirmed that sound field correction method is needed in the heavy/soft impact sound pressure level measurement method using bang machine and rubber ball.

Experimental Analysis of Tribological Properties of Biolubricant with Nanoparticle Additive

This study examined the tribological properties of two lubricating oils, paraffin oil and biolubricant added with TiO2 nanoparticles used as additives. Biolubricant used in this experimental was derived from palm oil-based TMP (trimethylolpropane) ester. The TMP ester is produced from palm oil, which is biodegradable and has high lubricity properties such as a higher flash point temperature and VI (viscosity index). The friction and wear experiments were performed using four- ball machine tribotester. Experimental was carried out for 10minutes under 40kg, 80kg, 120kg, and 160kg at 1200rpm. Test temperatures were set at room temperature. The experimental results show that nanoparticles, TiO2 added to TMP ester exhibit good friction-reduction. The addition of TiO2 nanoparticles in the TMP ester at 160kg decreased the friction coefficient by 15% respectively, and reduced the wear scar diameter by 11%respectively, as compared to TMP ester without TiO2 nanoparticles. In conclusion, TMP ester added with nanoparticles is environmentally desired to mineral oil based lubricants, research to investigate the properties of nanoparticle added with TMP ester to make it technologically competitive as automobile lubricant, and should be encouraged.

Attunement to haptic information helps skilled performers select implements for striking a ball in cricket

This study examined the perceptual attunement of relatively skilled individuals to the physical properties of striking implements in the sport of cricket. We also sought to assess whether utilizing bats with different physical properties would influence performance of a specific striking action: the front foot straight drive. Eleven skilled male cricketers (mean age = 16.6 ± 0.3years) from an elite school cricket development program consented to participate in the study. While blindfolded, participants wielded six bats exhibiting different mass and moment of inertia (MOI) characteristics and were asked to identify the three bats they preferred the most for hitting a ball to a maximum distance by performing a front foot straight drive (a common shot in cricket). Next, participants actually attempted to hit balls projected from a ball machine using each of the six bat configurations to enable kinematic analysis of front foot straight drive performance with each implement. Results revealed that, on first choice, the two bats with the smallest mass and MOI values (1 and 2) were most preferred by almost two thirds (63.7%) of the participants. Kinematic analysis of movement patterns revealed that bat velocity, step length, and bat-ball contact position measures significantly differed between bats. Data revealed how skilled youth cricketers were attuned to the different bat characteristics and harnessed movement system degeneracy to perform this complex interceptive action.

Preparation and tribological properties of surface modified Cu nanoparticles

Cu nanoparticles surface-modified by dioctylamine dithiocarbamate (DTC8) were synthesized using a two-phase extraction route. The size, morphology and structure of resultant surface-capped Cu nanoparticles (coded as DTC8-Cu) were analyzed by means of X-ray diffraction, transmission electron microscopy and infrared spectrometry. The tribological behavior of DTC8-Cu as an additive in liquid paraffin was evaluated with a four–ball machine, and the surface topography of the wear scar was also examined by means of scanning electron microscopy. Results show that Cu nanoparticles modified by DTC8 have a small particle size and a narrow size distribution. Besides, DTC8-Cu as an additive in liquid paraffin has excellent antiwear ability, due to the deposition of nano-Cu with low melting point on worn steel surface leading to the formation of a self-repairing protective layer thereon.

Enhancing cricket batting skill: implications for biomechanics and skill acquisition research and practice

This review synthesises the biomechanical and skill acquisition/sport expertise literature focused on the skill of cricket batting. The literature is briefly reviewed and the major limitations, challenges, and suggested future research directions are outlined. This is designed to stimulate researchers to enhance the understanding of cricket batting biomechanics and skill acquisition and in turn assist cricket coaches develop efficacious batting skill development programmes. An interdisciplinary approach between biomechanists and skill acquisition specialists is advocated to further knowledge of the underlying processes and mechanisms of cricket batting expertise. Issues such as skill measurement, practice design, ball machines, skill transfer, the impact of Twenty/20 cricket, video simulation, and skill decomposition are discussed. The ProBatter™ ball machine systems are introduced along with suggestions for best practice approaches for coaches when designing batting skill development programmes.

Research on Compound Servo Drive Control of Heavy Loading Feed Table

This paper described a new compound servo drive structure and control method of heavy loading feeding table. Feed and location of table are controlled by ball screw through the Servo motor, who’s mainly responsibility is for the movement positioning accuracy of the feed table; Moreover, the table has added a set of servo-hydraulic cylinder driver assistance systems. The two systems are synchronized by the mutual control, the stress situation and wear of the ball screw servo feed with the heavy loading can be improved, thus the dynamic response characteristics and long-term positioning accuracy of the servo feed table can be improved ,addition to, the life of ball bearings and machine tools guide can be enhanced.

The Hit & Turn Tennis Test: An acoustically controlled endurance test for tennis players

This study was conducted to validate and evaluate the “Hit & Turn Tennis Test”, an acoustically progressive on-court endurance test for tennis players. Ninety-eight competitive tennis players (53 males, 45 females) of different age groups participated in the study. For validation, the adult male players completed three Hit & Turn tests, one on a clay court and two on a carpet surface, a tennis-specific ball machine test and an incremental treadmill run in a randomized order. A stronger correlation between maximal performance (r = 0.81, P < 0.01) and maximal oxygen uptake (r = 0.96, P < 0.01) was observed between the Hit & Turn test and the ball machine test, than between the Hit & Turn test and the treadmill test. For test–retest, we found a significant correlation between maximal performance on the same (r = 0.83, P < 0.01) and on different surfaces (r = 0.74, P < 0.01). During test evaluation, maximal performance was higher in males than in females (P < 0.01) and increased by consecutive age group in boys (P < 0.01) but not in girls (P = 0.97). In conclusion, Hit & Turn maximum test performance can be recommended as a valid and reliable indicator for tennis-specific endurance.

The Dubai tennis ball machine

Subject area Ethics in IT, community informatics, management. Study level/applicability Undergraduate and postgraduate information technology and citizens' rights, strategic decision making. Case overview This case spotlights Athlete Sports in Dubai, United Arab Emirates (UAE). It focuses on the malfunction of the company's equipment that is rented from ABC Sports Equipment. Athlete Sports has been in the UAE over a decade and has positioned itself fairly at the top due to its qualified coaches and quality of facilities it provides. The case highlights the company's transition from owning equipment to leasing equipment that increases profits. However, it also sheds light on ABC Sports' venture into code reusability in order to upgrade equipments faster. The case looks closely at the ultimate consequences of ABC Sports' practice and the impact it has on Athlete's Sports' clients and the subsequent decisions the managers are expected to make. Expected learning outcomes This case can be used to teach strategic decision making, and ethics in information technology. Supplementary materials A teaching note is available on request.

Anticipační načasování riternu na základě odhadu dráhy letu míče

Ball-hitting in tennis involves spatio-temporal information about the ball’s fl ight trajectory. We have focused on the temporal part of the information during returning a tennis serve that was simulated by a ball machine. Th e tested people had occlusion glasses placed on their eyes, which occluded their vision at the exact time, when the ball was being sent from the ball machine. Th e tested person did not know which part of the ball fl ight trajectory would be occluded, nor the ball speed. We examined the eff ect of part ball fl ight trajectory occlusion on the correct return timing of the ball. Th e analysis revealed that the greatest problems occurred while the second third of the ball fl ight trajectory had been occluded and reached most temporal errors at that time.

Visual strategies of sub-elite cricket batsmen in response to different ball velocities

When different interceptive skills are considered, humans tend not to pursuit track the approaching object along its entire trajectory to the point of interception. Previous research of cricket batsmen facing medium paced deliveries reported pursuit visual tracking of the ball for the first 100–150 ms of flight followed by a saccade to the predicted ball bounce location. The aim of this study was to examine eye movements of batsmen while facing a range of slow to medium pace delivery speeds. Thirteen sub-elite batsmen faced 36 deliveries from a ball machine in which the projection speed was randomly varied across a range of 17–25 ms −1. The foveal gaze of the batsmen was recorded with a monocular eye movement registration system. Gaze strategies differed between participants in several ways, i.e., in the initial location of gaze prior to delivery (on the outlet of the ball machine or “parked” at a location on the predicted flight trajectory), the behavior immediately after ball release (pursuit tracking or saccade), and the behavior in mid-late flight (predictive saccade to the bounce point or “parafoveal” pursuit tracking). Across the range of delivery speeds used in the current study, it was possible to pursuit track the ball from release to bounce point but it was also possible to choose to make saccades along the trajectory. Depending on the spatio-temporal demands of the task and the intentions of the batsman a range of visual search strategies can be employed to support their actions.

Elite tennis player sensitivity to changes in string tension and the effect on resulting ball dynamics

Eighteen elite male tennis players were tested to determine their ability to identify string tension differences between rackets strung from 210 N (47 lb) to 285 N (64 lb). Each player impacted four tennis balls projected from a ball machine before changing rackets and repeating the test. Eleven participants (61%) could not correctly detect a 75 N (17 lb) difference between rackets. Only two participants (11%) could correctly detect a 25 N (6 lb) difference. To establish whether varying string tensions affected ball rebound dynamics, the ball’s rebound speed and landing position were analysed. The mean rebound ball speed was 117 km h−1, with only the trials from the 210 N racket producing significantly lower (P < 0.05) rebound speeds than the 235 N and 260 N rackets. This is contrary to previous laboratory-based tests where higher rebound speeds are typically associated with low-string tensions. The anomaly may be attributable to lower swing speeds from participants as they were not familiar with such a low string tension. Ball placement did not appear related to string tension, with the exception of more long errors for the 235 N racket and fewer long errors for the 285 N racket. It was concluded that elite male tennis players display limited ability to detect changes in string tension, impact the ball approximately 6% faster than advanced recreational tennis players during a typical rallying stroke, and that ball placement is predominantly unrelated to string tension for elite performers.