WorldWideScience

Sample records for surgery sport gear

  1. Robotic surgery training: construct validity of Global Evaluative Assessment of Robotic Skills (GEARS).

    Science.gov (United States)

    Sánchez, Renata; Rodríguez, Omaira; Rosciano, José; Vegas, Liumariel; Bond, Verónica; Rojas, Aram; Sanchez-Ismayel, Alexis

    2016-09-01

    The objective of this study is to determine the ability of the GEARS scale (Global Evaluative Assessment of Robotic Skills) to differentiate individuals with different levels of experience in robotic surgery, as a fundamental validation. This is a cross-sectional study that included three groups of individuals with different levels of experience in robotic surgery (expert, intermediate, novice) their performance were assessed by GEARS applied by two reviewers. The difference between groups was determined by Mann-Whitney test and the consistency between the reviewers was studied by Kendall W coefficient. The agreement between the reviewers of the scale GEARS was 0.96. The score was 29.8 ± 0.4 to experts, 24 ± 2.8 to intermediates and 16 ± 3 to novices, with a statistically significant difference between all of them (p robotic surgery and, therefore, is a validated and useful tool to evaluate surgeons in training.

  2. Performance and Return to Sport After Sports Hernia Surgery in NFL Players.

    Science.gov (United States)

    Jack, Robert A; Evans, David C; Echo, Anthony; McCulloch, Patrick C; Lintner, David M; Varner, Kevin E; Harris, Joshua D

    2017-04-01

    Recognition, diagnosis, and treatment of athletic pubalgia (AP), also known as sports hernia, once underrecognized and undertreated in professional football, are becoming more common. Surgery as the final treatment for sports hernia when nonsurgical treatment fails remains controversial. Given the money involved and popularity of the National Football League (NFL), it is important to understand surgical outcomes in this patient population. After AP surgery, players would: (1) return to sport (RTS) at a greater than 90% rate, (2) play fewer games for fewer years than matched controls, (3) have no difference in performance compared with before AP surgery, and (4) have no difference in performance versus matched controls. Cohort study; Level of evidence, 3. Internet-based injury reports identified players who underwent AP surgery from January 1996 to August 2015. Demographic and performance data were collected for each player. A 1:1 matched control group and an index year analog were identified. Control and case performance scores were calculated using a standardized scoring system. Groups were compared using paired Student t tests. Fifty-six NFL players (57 AP surgeries) were analyzed (mean age, 28.2 ± 3.1 years; mean years in NFL at surgery, 5.4 ± 3.2). Fifty-three players were able to RTS. Controls were in the NFL longer (P .05) difference in pre- versus post-AP surgery performance scores and no significant (P > .05) difference in postoperative performance scores versus controls post-index. There was a high RTS rate after AP surgery without a significant difference in postoperative performance, though career length and games per season after AP surgery were significantly less than that of matched controls.

  3. Psychological responses matter in returning to preinjury level of sport after anterior cruciate ligament reconstruction surgery.

    Science.gov (United States)

    Ardern, Clare L; Taylor, Nicholas F; Feller, Julian A; Whitehead, Timothy S; Webster, Kate E

    2013-07-01

    Up to two-thirds of athletes may not return to their preinjury level of sport by 12 months after anterior cruciate ligament (ACL) reconstruction surgery, despite being physically recovered. This has led to questions about what other factors may influence return to sport. To determine whether psychological factors predicted return to preinjury level of sport by 12 months after ACL reconstruction surgery. Case control study; Level of evidence, 3. Recreational and competitive-level athletes seen at a private orthopaedic clinic with an ACL injury were consecutively recruited. The primary outcome was return to the preinjury level of sports participation. The psychological factors evaluated were psychological readiness to return to sport, fear of reinjury, mood, emotions, sport locus of control, and recovery expectations. Participants were followed up preoperatively and at 4 and 12 months postoperatively. In total, 187 athletes participated. At 12 months, 56 athletes (31%) had returned to their preinjury level of sports participation. Significant independent contributions to returning to the preinjury level by 12 months after surgery were made by psychological readiness to return to sport, fear of reinjury, sport locus of control, and the athlete's estimate of the number of months it would take to return to sport, as measured preoperatively (χ(2) 2 = 18.3, P sport at 12 months, suggesting that attention to psychological recovery in addition to physical recovery after ACL injury and reconstruction surgery may be warranted. Clinical screening for maladaptive psychological responses in athletes before and soon after surgery may help clinicians identify athletes at risk of not returning to their preinjury level of sport by 12 months.

  4. Gears and gear drives

    CERN Document Server

    Jelaska, Damir T

    2012-01-01

    Understanding how gears are formed and how they interact or 'mesh' with each other is essential when designing equipment that uses gears or gear trains. The way in which gear teeth are formed and how they mesh is determined by their geometry and kinematics, which is the topic of this book.  Gears and Gear Drives provides the reader with comprehensive coverage of gears and gear drives. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. Cylindric

  5. What surgeons can learn from athletes: mental practice in sports and surgery.

    Science.gov (United States)

    Cocks, Margaret; Moulton, Carol-Anne; Luu, Shelly; Cil, Tulin

    2014-01-01

    Mental practice has been successfully applied in professional sports for skills acquisition and performance enhancement. The goals of this review are to describe the literature on mental practice within sport psychology and surgery and to explore how the specific principles of mental practice can be applied to the improvement of surgical performance-both in novice and expert surgeons. The authors reviewed the sports psychology, education, and surgery literatures through Medline, PubMed, PsycINFO, and Embase. In sports, mental practice is a valuable tool for optimizing existing motor skill sets once core competencies have been mastered. These techniques have been shown to be more advantageous when used by elite athletes. Within surgery, mental practice studies have focused on skill acquisition among novices with little study of how expert surgeons use it to optimize surgical preparation. We propose that performance optimization and skills acquisition should be viewed as 2 separate domains of mental practice. Further understanding of this phenomenon has implications for changing how we teach and train not only novice surgeons but also how experienced surgeons continue to maintain their skills, acquire new ones, and excel in surgery. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  6. Combining Clinical Information and Patient Reported Outcome Measures in Orthopaedic Surgery and Sports Medicine

    NARCIS (Netherlands)

    Kampen, D.A. van

    2013-01-01

    In this thesis we investigated the use of clinical information and Patient Reported Outcome Measures (PROMs) for patient evaluation in orthopaedic surgery and sports medicine. In the first part, we showed that the Dutch version of the Simple Shoulder Test (SST) is a valid and reliable

  7. Combining Clinical Information and Patient Reported Outcome Measures in Orthopaedic Surgery and Sports Medicine

    NARCIS (Netherlands)

    Kampen, D.A. van

    2013-01-01

    In this thesis we investigated the use of clinical information and Patient Reported Outcome Measures (PROMs) for patient evaluation in orthopaedic surgery and sports medicine. In the first part, we showed that the Dutch version of the Simple Shoulder Test (SST) is a valid and reliable instrumen

  8. History of computer-assisted orthopedic surgery (CAOS) in sports medicine.

    Science.gov (United States)

    Jackson, Douglas W; Simon, Timothy M

    2008-06-01

    Computer-assisted orthopedic surgery and navigation applications have a history rooted in the desire to link imaging technology with real-time anatomic landmarks. Although applications are still evolving in the clinical and research setting, computer-assisted orthopedic surgery has already demonstrated in certain procedures its potential for improving the surgeon's accuracy, reproducibility (once past the learning curve), and in reducing outlier outcomes. It is also being used as an educational tool to assist less experienced surgeons in interpreting measurements and precision placements related to well defined anatomic landmarks. It also can assist experienced surgeons, in real-time, plan their bony cuts, tunnel placement, and with ligament balancing. Presently, the additional time, the expense to acquire the needed software and hardware, and restricted reimbursement have slowed the widespread use of navigation. Its current applications have been primarily in joint replacement surgery, spine surgery, and trauma. It has not been widely used in the clinical setting for sports medicine procedures. Sports medicine applications such as individualizing tunnel placement in ligament surgery, opening wedge osteotomy with and without accompanying ligament reconstruction, and balancing and tensioning of the ligaments during the procedure (allowing real-time corrections if necessary) are currently being evaluated and being used on a limited clinical basis.

  9. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  10. sports

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    正Nowadays,high school students hold different opinions about after-class activities.There are two quite different phenomenonena.Some students are crazy about sports and some other activities.They spend much time in joining the outdoor activities and varies of groups,and also,making new friends.However,they pay a little attention to their studies.

  11. Sports-related Head Injury

    Science.gov (United States)

    ... difficulty expressing words or thoughts; dysarthric speech Head Injury Prevention Tips Buy and use helmets or protective head gear approved by the ASTM for specific sports 100 percent of the time. The ASTM has ...

  12. The Influence of Medical Insurance on Patient Access to Orthopaedic Surgery Sports Medicine Appointments Under the Affordable Care Act.

    Science.gov (United States)

    Wiznia, Daniel H; Nwachuku, Emmanuel; Roth, Alexander; Kim, Chang-Yeon; Save, Ameya; Anandasivam, Nidharshan S; Medvecky, Michael; Pelker, Richard

    2017-07-01

    The goal of the Patient Protection and Affordable Care Act (PPACA) was to expand patient access to health care. Since the rollout of the PPACA, Medicaid patients have demonstrated difficulty obtaining appointments in some specialty care settings. To assess the effect of insurance type (Medicaid and private) on patient access to orthopaedic surgery sports medicine specialists for a semiurgent evaluation of a likely operative bucket-handle meniscus tear. The study was designed to determine whether disparities in access exist since the PPACA rollout. Cohort study; Level of evidence, 2. The design was to call 180 orthopaedic surgery sports medicine specialists in 6 representative states (California, Ohio, New York, Florida, Texas, and North Carolina) between June 2015 and December 2015. An appointment was requested for the caller's fictitious 25-year-old-brother who had suffered a bucket-handle meniscus tear. Each office was called twice to assess the ease of obtaining an appointment: once for patients with Medicaid and once for patients with private insurance. For each call, data pertaining to whether an appointment was given, wait times, and barriers to receiving an appointment were recorded. A total of 177 surgeons were called within the study period. Overall, 27.1% of offices scheduled an appointment for a patient with Medicaid, compared with 91.2% (P < .0001) for a patient with private insurance. Medicaid patients were significantly more likely to be denied an appointment due to lack of referral compared with private patients (40.2% vs 3.7%, P < .0001), and Medicaid patients were more likely to experience longer wait times for an appointment (15 vs 12 days, P < .029). No significant differences were found in patients' access to orthopaedic surgery sports medicine specialists between Medicaid-expanded and -nonexpanded states. Medicaid reimbursement for knee arthroscopy with meniscus repair was not significantly correlated with appointment success rate or patient

  13. Analgesic efficacy of intra-articular morphine after arthroscopic knee surgery in sport injury patients

    Directory of Open Access Journals (Sweden)

    Mitra Yari

    2013-07-01

    Full Text Available BACKGROUND: Anterior Cruciate Ligament (ACL tearing is a common injury among football players. The present study aims to determine the best single-dose of intra-articular morphine for pain relief after arthroscopic knee surgery that, in addition to adequate and long-term analgesia, leads to fewer systemic side effects. METHODS: This clinical trial was conducted on 40 ASA-I athletes. After surgery, all participants received an injection of 20cc of 0.5% intra-articular bupivacaine. In addition, the first control group received a saline injection and 5, 10 and 15 mg of morphine were respectively injected into the joints of the second, third and fourth groups by use of Arthroscopic equipment before the Arthroscopic removal. The amount of pain based on VAS at 1, 2, 4, 6 and 24 hours after surgery, duration of analgesia and the consumption of narcotic drugs were recorded. RESULTS: The VAS scores in the fourth, sixth and twenty-fourth hours after surgery showed a significant difference between the study groups. The average time to the first analgesic request from the bupivacaine plus 15 mg morphine group was significantly longer than other groups and total analgesic requests were significantly lower than other groups. No drowsiness complications were observed in any of the groups in the first 24 hours after injection. CONCLUSION: Application of 15 mg intra-articular morphine after Arthroscopic knee surgery increases the analgesia level as well as its duration (IRCT138902172946N3 .

  14. Preventing Musculoskeletal Sports Injuries in Youth: A Guide for Parents

    Science.gov (United States)

    ... physical condition to play the sport. Follow the rules of the sport. Wear appropriate protective gear (for example, shin guards for soccer, a hard-shell helmet when facing a baseball or softball pitcher, a helmet and body padding ...

  15. Cold-Weather Sports

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Cold-Weather Sports KidsHealth > For Teens > Cold-Weather Sports A A A What's in this article? ... Equipment Ahh, winter! Shorter days. Frigid temperatures. Foul weather. What better time to be outdoors? Winter sports ...

  16. Performance and Return-to-Sport after Tommy John Surgery in Major League Baseball Pitchers

    Science.gov (United States)

    Gupta, Anil Kumar; Erickson, Brandon J.; Harris, Joshua David; Bach, Bernard R.; Abrams, Geoffrey D.; Juan, Angielyn San; Cole, Brian J.; Bush-Joseph, Charles A.; Romeo, Anthony A.

    2014-01-01

    Objectives: Ulnar collateral ligament reconstruction (UCLR) is a common procedure performed in Major League Baseball (MLB) pitchers with symptomatic UCL deficiencies. The purpose of this study was to determine: 1) the rate of return to pitching in the MLB following UCLR, 2) performance after return to pitching, and 3) the difference in return to pitching and performance between pitchers who underwent UCLR and matched controls who did not. Methods: MLB pitchers with symptomatic UCL deficiency that underwent UCLR between 1986 and 2012 were evaluated. Players' data was extracted from MLB team websites, injury reports, player profiles/biographies, press releases and cross-referenced with the MLB injury database (MLB411). All player, elbow, and surgical demographic data were analyzed. Age, body mass index (BMI), position, handedness, and MLB experience-matched controls were selected from the MLB during the same years as those undergoing UCLR. An "index year" was designated for controls, analogous to UCLR year in cases. Return to pitching and performance measures in MLB was compared between cases and controls. Student's t-tests were performed for analysis of within-group and between-group variables, respectively. Results: One hundred forty-eight pitchers (83%) were able to return to pitching in MLB. Length of career in MLB following UCLR was 3.9 +/- 2.84 years. Revision rate was 3.9%. In the year prior to UCLR (or index year in controls), cases were significantly (p<0.05) worse than controls with regard to number of innings pitched, games played, wins, and winning percentage and were not significantly different than controls in all remaining parameters. Pitchers undergoing UCLR had significantly (p<0.05) fewer losses, a lower losing percentage, and lower earned run average (ERA) following surgery (versus pre-surgery). In addition, cases threw significantly (p<0.05) fewer walks and allowed fewer hits, runs, and home runs following surgery. Comparisons between cases and

  17. Modern gear production

    CERN Document Server

    Watson, H J

    1970-01-01

    Modern Gear Production focuses on the processes and methods in gear making. The book first gives information on the history of gear making and types of gears. Topics such as the classification of gears based on the disposition of their shafts; shafts lying in the same plane with axes intersecting; and shafts lying in parallel planes but with axes inclined to one another are then discussed. The text describes gear groups, tooth forms, and gear materials. Heat treatment of steels, casehardening, nitriding, induction hardening, sulfinuzing, and flame hardening are explained. The book takes a look

  18. Electromechanical integrated magnetic gear

    OpenAIRE

    Xiu-hong Hao; Hong-fei Zhang; Ji-de Men

    2016-01-01

    This study proposes a new type of magnetic gear, namely, the electromechanical integrated magnetic gear, that integrates the traditional field-modulated magnetic gear, drive, and control. The topology and operating principle of the electromechanical integrated magnetic gear are described in detail in this article, and the constraints of parameter design and speed ratio of electromechanical integrated magnetic gear are presented. Moreover, magnetic field distribution is analyzed with the finit...

  19. Changing gear

    Energy Technology Data Exchange (ETDEWEB)

    Scott-Smith, P. [P.A.L. Management, Dunrobin, ON (Canada)

    1997-11-01

    Experiences learned during the past ten years in marketing geothermal heat pumps were recalled and future actions to increase market penetration for this technology were considered. According to this speaker, the events of the last ten years have clearly demonstrated that technology development, however desirable in socio-economic terms, is only as good as the ability to market and deliver the product in an efficient and cost effective manner. Studies over the past two years have revealed an almost universal distrust of energy and water service providers, the scarcity of reliable information and advice on technology options, and high levels of skepticism among contractors about most of the modern and environmentally-preferred technology options. Based on this evidence, it was concluded that there is an urgent need for the environmentally-preferred technology industry to `change gears`, to reassess its marketing and service delivery practices towards a more consumer-friendly process that includes education, information and guidance. It was emphasized that if energy use efficiency and responsible environmental management is to become a legitimate option for the consideration of consumers it must be freed from the hands of opportunistic service providers, and be backstopped by a dedicated approach to marketing, management and consumer relations.

  20. Modular gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2009-01-01

    A gearing system using modular gear bearing components. Each component is composed of a core, one or more modules attached to the core and two or more fastening modules rigidly attaching the modules to the core. The modules, which are attached to the core, may consist of gears, rollers or gear bearing components. The core orientation affects the orientation of the modules attached to the core. This is achieved via the keying arrangement of the core and the component modules that attach to the core. Such an arrangement will also facilitate the phase tuning of gear modules with respect to the core and other gear modules attached to the core.

  1. Kinematic geometry of gearing

    CERN Document Server

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  2. Anti-backlash gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2009-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission. One preferred embodiment discloses and describes an anti-backlash feature to counter ''dead zones'' in the gear bearing movement.

  3. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Surgery? Choosing the Right Sport for You Shyness A Guide to Eating for Sports KidsHealth > For Teens > ... perform your best while also losing weight. Eat a Variety of Foods You may have heard about " ...

  4. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  5. Offset Compound Gear Drive

    Science.gov (United States)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  6. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  7. Estimating Gear Teeth Stiffness

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact length is constant....

  8. Modelling polymer draft gears

    Science.gov (United States)

    Wu, Qing; Yang, Xiangjian; Cole, Colin; Luo, Shihui

    2016-09-01

    This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2 m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears' in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections.

  9. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp gun;...

  10. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3)...

  11. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Allowable gear and gear restrictions. 665... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken only with the following allowable gear and methods: (1) Hand harvest; (2) Spear; (3) Slurp gun;...

  12. Return to Sport Following Surgery for a Complicated Tibia and Fibula Fracture in a Collegiate Women's Soccer Player with a Low Level of Kinesiophobia.

    Science.gov (United States)

    Feigenbaum, Luis A; Baraga, Michael; Kaplan, Lee D; Roach, Kathryn E; Calpino, Kathryn M; Dorsey, Katie; Martorelli, Cristina; Sagarduy, Beatriz; King, Lesley-Anne; Scavo, Vincent A

    2015-02-01

    Much attention has been solely paid to physical outcome measures for return to sport after injury in the past. However, current research shows that the psychological component of these injuries can be more predictive of return to sport than physical outcome measures. The purpose of this case report is to describe the successful return to sport following surgery of a complicated tibia and fibula fracture of a Division I collegiate women's soccer player with a low level of kinesiophobia. A 22-year-old female sustained a closed traumatic mid-shaft fracture of her tibia and fibula. During a high velocity play she sustained a direct blow while colliding with an opposing player's cleats. As a result of the play, her distal tibia was displaced 908 to the rest of her leg. She underwent a closed reduction and tibial internal fixation with an intramedullary rod. Outcome scores were tracked using the IKDC and TSK-11. The IKDC measures symptoms, function, and sport activity related to knee injuries. The TSK-11 measures fear of movement and re-injury, which was important to assess during this case due to the gruesome nature of the injury. At 4 months, the subject became symptomatic over the fibula and was diagnosed with a fibular nonunion fracture. This was unexpected due to the low incidence of and usual asymptomatic nature of fibular nonunion fractures, which required an additional surgery. TSK-11 scores ranged from 19-20 throughout, signifying low levels of kinesiophobia. IKDC scores improved from 8.05 to 60.92. The subject ultimately signed a professional soccer contract. The rehabilitation of this subject was complex due to her low levels of kinesiophobia, self-guided overtraining, and the potential role they may have had in her fibular nonunion fracture. This case study demonstrates a successful outcome despite a unique injury presentation, multiple surgeries, and low levels of kinesiophobia. While a low level of kinesiophobia can be detrimental to rehabilitation

  13. Electromechanical integrated magnetic gear

    Directory of Open Access Journals (Sweden)

    Xiu-hong Hao

    2016-06-01

    Full Text Available This study proposes a new type of magnetic gear, namely, the electromechanical integrated magnetic gear, that integrates the traditional field-modulated magnetic gear, drive, and control. The topology and operating principle of the electromechanical integrated magnetic gear are described in detail in this article, and the constraints of parameter design and speed ratio of electromechanical integrated magnetic gear are presented. Moreover, magnetic field distribution is analyzed with the finite element method. Subsequently, the harmonics of the magnetic field and the electromagnetic torque are calculated. The static torques on all the components are exhibited by finite element method and torque test. The effects of the design parameters on the torques and the torque densities are discussed, and the results show that electromechanical integrated magnetic gear has a high speed ratio and can generate a high torque at low speed. The maximum torques are affected by air-gap thickness and other parameters.

  14. Planetary gear train ring gear and support structure investigation

    Science.gov (United States)

    Valco, Mark J.

    1992-01-01

    Most helicopter transmissions utilize a planetary gear train as the final speed reduction stage. Due to weight constraints these transmissions have high power-to-weight ratios and relatively flexible structures. This investigation addresses the analysis of planetary gear trains with the ring gear mounted on a flexible support structure. The approach utilizes recent advances in automated contact methods for nonlinear finite element analysis. Rather than using a line of action spring to model gear pair mesh stiffness, finite element models of complete gears are developed, and the elastic gear members are engaged and rolled through mesh. The procedure includes detailed gear tooth geometry with profile modifications. A nonlinear approach is required due to large displacements associated with gear rotation and nonlinear boundary conditions associated with the gear tooth surface contact. The updated Lagrangian formulation and the MARC K-4.1 automated contact features are applied in the analysis. The ring gear support structure is modeled by an elastic foundation linking the ring gear to a rigid support. Calculation of gear pair deflections, stresses, transmission error, and mesh stiffness through the gear meshing cycle are demonstrated for external and internal spur gear pairs and a planetary gear train. Issues relating to the accuracy of the nonlinear finite element contact method, gear mesh stiffness, transmission error, and the planetary gear train elastic support structure are discussed.

  15. Sports Season, Sports Bars

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ For foreigners in Beijing, the sports bar is a special place, a place to gather for watching matches and a place to feel the familiarity of home, while for some sports enthusiasts it serves as their second home.

  16. Gear Crack Propagation Investigation

    Science.gov (United States)

    1995-01-01

    Reduced weight is a major design goal in aircraft power transmissions. Some gear designs incorporate thin rims to help meet this goal. Thin rims, however, may lead to bending fatigue cracks. These cracks may propagate through a gear tooth or into the gear rim. A crack that propagates through a tooth would probably not be catastrophic, and ample warning of a failure could be possible. On the other hand, a crack that propagates through the rim would be catastrophic. Such cracks could lead to disengagement of a rotor or propeller from an engine, loss of an aircraft, and fatalities. To help create and validate tools for the gear designer, the NASA Lewis Research Center performed in-house analytical and experimental studies to investigate the effect of rim thickness on gear-tooth crack propagation. Our goal was to determine whether cracks grew through gear teeth (benign failure mode) or through gear rims (catastrophic failure mode) for various rim thicknesses. In addition, we investigated the effect of rim thickness on crack propagation life. A finite-element-based computer program simulated gear-tooth crack propagation. The analysis used principles of linear elastic fracture mechanics, and quarter-point, triangular elements were used at the crack tip to represent the stress singularity. The program had an automated crack propagation option in which cracks were grown numerically via an automated remeshing scheme. Crack-tip stress-intensity factors were estimated to determine crack-propagation direction. Also, various fatigue crack growth models were used to estimate crack-propagation life. Experiments were performed in Lewis' Spur Gear Fatigue Rig to validate predicted crack propagation results. Gears with various backup ratios were tested to validate crack-path predictions. Also, test gears were installed with special crack-propagation gages in the tooth fillet region to measure bending-fatigue crack growth. From both predictions and tests, gears with backup ratios

  17. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  18. Gear noise origins

    Science.gov (United States)

    Mark, W. D.

    1985-01-01

    Each pair of meshing gears in a transmission gives rise to a source of vibratory excitation that can result in the radiation of sound. Each such source is most conveniently characterized as a displacement form of excitation generally referred to as the static transmission error of the gear pair. Contributions to the frequency spectrum of the static transmission error of spur and helical gears arising from tooth and gear body elastic deformations and from deviations of tooth surfaces from perfect involute surfaces are considered. Tooth surface deviations are decomposed into contributions giving rise to tooth meshing harmonic excitations and rotational harmonic or sideband excitations. Various types of gear tooth errors are defined and the contributions of these errors to different parts of the frequency spectrum are described. The attenuating effect on the static transmission error spectrum arising from the smoothing action of multiple tooth contact is explained.

  19. Fishing gear-related injury in California marine wildlife.

    Science.gov (United States)

    Dau, Brynie Kaplan; Gilardi, Kirsten V K; Gulland, Frances M; Higgins, Ali; Holcomb, Jay B; Leger, Judy St; Ziccardi, Michael H

    2009-04-01

    fishing gear-lost, abandoned or discarded sport and commercial line, nets, traps, etc.-in the marine environment is a significant cause of injury in California coastal marine wildlife. We evaluated data for stranded animals only; our results may underestimate the true number of coastal marine animals injured by lost or discarded fishing gear in California.

  20. The Degree of Shoulder Involvement in Sports (DOSIS) scale is a valid and responsive instrumentation for shoulder assessment in patients after surgery for anterior instability.

    Science.gov (United States)

    Vascellari, Alberto; Ramponi, Carlo; Venturin, Davide; Ben, Giulia; Blonna, Davide; Coletti, Nicolò

    2017-07-18

    The purpose of this study was to evaluate validity and responsiveness of the Degree of Shoulder Involvement in Sport (DOSIS) scale. A web-based survey was developed to test the construct validity of the DOSIS scale. Fifty-three patients with a median age of 33 years (range 17-59) were included in the study. Convergent validity was evaluated by external correlation (Spearman's rank correlation coefficient, r) of the DOSIS with the Brophy-Marx and Tegner activity scales, the Western Ontario shoulder instability index (WOSI), the Simple Shoulder Test (SST), and the Short-Form 36 (SF-36). Responsiveness was analysed by relative efficiency calculation of the DOSIS versus the Brophy-Marx and Tegner activity scales. The DOSIS showed strong correlation with the Brophy-Marx and Tegner activity scales, a moderate correlation with the WOSI and SST scores, and a moderate correlation with the physical functioning, role physical and role emotional subscores of the SF-36. The distribution of the DOSIS scores had no serious ceiling or floor effects. The DOSIS demonstrated lesser responsiveness when compared to the Brophy-Marx and Tegner activity scales. The DOSIS showed an adequate validity and responsiveness. The clinical relevance of this study is that the DOSIS scale can be used for sport-specific shoulder assessment in patients after surgery for anterior instability. III.

  1. High-Ratio Gear Train

    Science.gov (United States)

    Lefever, A. E.

    1982-01-01

    Proposed arrangement of two connected planetary differentials results in gear ratio many times that obtainable in conventional series gear assembly of comparable size. Ratios of several thousand would present no special problems. Selection of many different ratios is available with substantially similar gear diameters. Very high gear ratios would be obtained from small mechanism.

  2. Team Sports

    Science.gov (United States)

    ... and sports prosthetics, as well as expenses for training and competition. Disabled Sports USA offers nationwide sports programs to anyone with a physical disability. Activities include winter skiing, water sports, summer ...

  3. Computing Stresses In Spur Gears

    Science.gov (United States)

    Oswald, F. B.; Lin, H. H.

    1995-01-01

    Dynamic Analysis of Spur Gear Transmissions (DANST) developed as easy-to-use program for static and dynamic analysis of spur-gear systems. Used for parametric studies to predict effects of operating speed, torque, stiffness, damping, inertia, and tooth profile on dynamic loads and tooth-bending stresses in spur gears. Performs geometric modeling and dynamic analysis for low- or high-contact-ratio spur gears. Simulates gear systems with contact ratios ranging from one to three. Written in FORTRAN 77.

  4. The cycloid Permanent Magnetic Gear

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Andersen, Torben Ole; Jørgensen, Frank T.

    2008-01-01

    This paper presents a new permanent-magnet gear based on the cycloid gearing principle. which normally is characterized by an extreme torque density and a very high gearing ratio. An initial design of the proposed magnetic gear was designed, analyzed, and optimized with an analytical model...... regarding torque density. The results were promising as compared to other high-performance magnetic-gear designs. A test model was constructed to verify the analytical model....

  5. Crankshaft gearing. Kurbelwellengetriebe

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, W.; Brunner, H.

    1990-12-13

    Crankshaft gearing. In this, the driven shaft of a main engine is connected at its free end to the main shaft by an elastic coupling. The crankshaft gearing with its housing is made directly as a flanged gearing for the engine or with its housing is fixed as a separate unit independent of the engine on the same or a separate base. It is characterized by the fact that to accommodate the alternating torque of the engine a double Cardan geared spindle and a coupling damping rotary vibration are provided by its crankshaft, from which the coupling acts as a hollow shaft and to support the drive wheel and in which it is fitted in a force-locking manner.

  6. Communication: Molecular gears

    Science.gov (United States)

    Burnell, E. Elliott; de Lange, Cornelis A.; Meerts, W. Leo

    2016-09-01

    The 1H nuclear magnetic resonance spectrum of hexamethylbenzene orientationally ordered in the nematic liquid crystal ZLI-1132 is analysed using covariance matrix adaptation evolution strategy. The spectrum contains over 350 000 lines with many overlapping transitions, from which four independent direct dipolar couplings are obtained. The rotations of the six methyl groups appear to be correlated due to mutual steric hindrance. Adjacent methyl groups show counter-rotating or geared motion. Hexamethylbenzene thus behaves as a molecular hexagonal gear.

  7. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ..., Johnston Atoll and Palmyra Atoll. (d) Existing FEP fisheries shall follow the allowable gear and methods... decision on the permissibility of this gear type will be made by the Regional Administrator...

  8. Magnetic Gearing Versus Conventional Gearing in Actuators for Aerospace Applications

    Science.gov (United States)

    Puchhammer, Gregor

    2014-01-01

    Magnetic geared actuators (MGA) are designed to perform highly reliable, robust and precise motion on satellite platforms or aerospace vehicles. The design allows MGA to be used for various tasks in space applications. In contrast to conventional geared drives, the contact and lubrication free force transmitting elements lead to a considerable lifetime and range extension of drive systems. This paper describes the fundamentals of magnetic wobbling gears (MWG) and the deduced inherent characteristics, and compares conventional and magnetic gearing.

  9. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  10. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  11. A superconducting magnetic gear

    Science.gov (United States)

    Campbell, A. M.

    2016-05-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844-46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further.

  12. Gear Fatigue Diagnostics and Prognostics

    Science.gov (United States)

    2013-01-01

    The first objective was to collect meaningful gear fault progression data starting from healthy NASA-designed spur test gears and ending with failed...and D. P. Townsend, "Analysis of the effects of surface pitting and wear on the vibration of a gear transmission system," Tribology International...Reporting Period: April 15, 2012 to September 27, 2012 Attached is the Gear Fatigue Diagnostics and Prognostics project progress report for the

  13. Sports physical

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000673.htm Sports physical To use the sharing features on this page, ... routine checkups. Why do you Need a Sports Physical? The sports physical is done to: Find out ...

  14. 75 FR 554 - Pacific Halibut Fisheries; Limited Access for Guided Sport Charter Vessels in Alaska

    Science.gov (United States)

    2010-01-05

    ... A comprehensive history of management of the guided sport fishery for halibut was presented in the... IPHC regulations at section 25 of the annual management measures specify the legal gear for sport... IPHC regulations at section 28 of the annual management measures establish sport fishing rules...

  15. Sport tourism

    Directory of Open Access Journals (Sweden)

    Eva Schwartzhoffová

    2010-03-01

    Full Text Available Sport tourism is one specific type of travel and tourism. The goal of this article is to introduce the definition and importance of sport tourism to academic and sports professionals. At present, sport tourism is a diverse social, economic and cultural phenomenon arising from the unique interaction of activity, people and place. The second part of this article reports about sports events as an important part of sport tourism.

  16. Research on theory of gearing for epicycloidal bevel gear

    Institute of Scientific and Technical Information of China (English)

    ZOU Min; ZHU Hai-lin; ZHANG You-liang

    2005-01-01

    The engaged feature of a pair of gears was determined by the geometrical characteristics of their tooth surfaces. Through an analysis of gearing theory on epicycloidal bevel gears, the method to examine if there exists undercut during manufacturing of epicycloidal bevel gears, the approximate formulae to calculate the gap between the convex and concave tooth surfaces in meshing so as to guarantee against the occurrence of point-contact for tooth surfaces even in maximum angle of inclination are derived in this paper. Those formula derived are simple, compact and have practical value to the design and production of epicycloidal bevel gears.

  17. A SPORTS FESTIVAL IN NIGERIA

    African Journals Online (AJOL)

    Departments of Oral and Maxillofacial Surgery and Pathology, *Rest0rative Dentistry, College of Medical .... sustained multiple injuries of tooth avulsion, tooth fracture and .... a German study could not associate physical fitness and sports-.

  18. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Loss Surgery? A Week of Healthy Breakfasts Shyness A Guide to Eating for Sports KidsHealth > For Teens > ... perform your best while also losing weight. Eat a Variety of Foods You may have heard about " ...

  19. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Who Can Get Weight Loss Surgery? Choosing the Right Sport for You Shyness A Guide to Eating ... diet or supplements. It's all about working the right foods into your fitness plan in the right ...

  20. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Get Weight Loss Surgery? A Week of Healthy Breakfasts Shyness A Guide to Eating for Sports KidsHealth > ... only one type of food. Carbohydrates are an important source of fuel, but they're only one ...

  1. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffnesses of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact width is constant. © 2014...

  2. Displaceable Gear Torque Controlled Driver

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  3. Bevel gear fundamentals and applications

    CERN Document Server

    2016-01-01

    This is the first book to offer a complete presentation of bevel gears. An expert team of authors highlights the areas of application for these machine elements and presents the geometrical features of bevel gears as well as the various gear cutting processes based on gear cutting theory. The aspect of three-dimensional gearing is assessed in detail in terms of flank design, load capacity and noise behavior. A representation of production processes with the required technologies provides a knowledge base on which sound decisions can be based. The authors offer a thorough introduction to the complex world of bevel gears and present the rapid advances of these machine elements in a detailed, comprehensible manner.  This book addresses design engineers in mechanical engineering and vehicle manufacturing, as well as producers of bevel gears and students in mechanical engineering.

  4. Numerical Analysis of Plastic Gear Stiffness

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper established practical 3-D gear models to study the stiffness influencing factors of a loaded gear by finite element method, such as friction parameters, material properties, and gear structures. The research shows that, in elastic deformation, gear stiffness increases when sliding friction ability of contact pair decreases;meanwhile, the gear structure, especially asymmetric design in gear's shaft direction will also decrease gear stiffness.

  5. Sports Tourism

    Directory of Open Access Journals (Sweden)

    Gozalova Marina

    2014-07-01

    Full Text Available Introduction. This article is devoted to sports tourism. The purpose of this article is to examine theoretical material on sports tourism, to analyze sports tourism in Russia and to search for promising areas for the study of sports tourism in our country. Material and methods. In this part the authors develop the idea of the role of doing sports and keeping fit. For anyone who really wants to be healthy, fitness has become an integral part of their lives. Results. The purpose of this research is to study theoretical material on sports tourism, to analyze sports tourism in Russia and to search for promising areas for the study of sports tourism in our country. On the basis of their research the authors come to the conclusion that sports and tourism are interconnected. There are important factors affecting the situation of sports tourism in Russia. The paper examines sports tourism attractions in Russia. Conclusion. The authors conclude that there exists a high correlation dependence of foreign and domestic development of sports tourism on resources allocated for sports infrastructure. All in all, sports tourism tours draw visitors to their favorite sporting event, facility, or destination throughout the world.

  6. Tool Gear Documentation

    Energy Technology Data Exchange (ETDEWEB)

    May, J; Gyllenhaal, J

    2002-04-03

    Tool Gear is designed to allow tool developers to insert instrumentation code into target programs using the DPCL library. This code can gather data and send it back to the Client for display or analysis. Tools can use the Tool Gear client without using the DPCL Collector. Any collector using the right protocols can send data to the Client for display and analysis. However, this document will focus on how to gather data with the DPCL Collector. There are three parts to the task of using Tool Gear to gather data through DPCL: (1) Write the instrumentation code that will be loaded and run in the target program. The code should be in the form of one or more functions, which can pass data structures back to the Client by way of DPCL. The collections of functions is compiled into a library, as described in this report. (2) Write the code that tells the DPCL Collector about the instrumentation and how to forward data back to the Client. (3) Extend the client to accept data from the Collector and display it in a useful way. The rest of this report describes how to carry out each of these steps.

  7. APPLICATION OF ASYMMETRIC PROFILE IN GEARINGS WITH ECCENTRIC GEARS

    OpenAIRE

    2014-01-01

    Gearing was designed to meet specific requirement, during one rotation was continuous change of gear ratio. The gearing consists of two identical gears. The basic shape of the wheel is formed by an ellipse. One of the foci is the center of rotation. Wheels are designed for only one direction of rotation. Active and passive side involute curve were created by rolling the basic evoluta elliptical wheel independently. It was used for the production of NC cutting machine for EDM 005 B EIR with ma...

  8. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  9. Research on synchronous gear pump

    Institute of Scientific and Technical Information of China (English)

    LUAN Zhen-hui

    2010-01-01

    Based on a comprehensive analysis of the structure and existing problems of the gear pump, provided a structure principle of a synchronous gear pump. The discussions focused on the working principle, construction features and finite element analysis of the hydraulic gear. The research indicates that the new pump has such advantages as lower noise, better distributed flow and a high work pressure, and it can be widely used in hydraulic systems.

  10. Design and construction of permanent magnetic gears

    DEFF Research Database (Denmark)

    Jørgensen, Frank Thorleif

    This thesis deals with design and development of permanent magnetic gears. The goal of this thesis is to develop knowledge and calculation software for magnetic gears. They use strong NdFeB permanent magnets and a new magnetic gear technology, which will be a serious alternative to classical...... calculation models for determination of gear output torque from different magnetic gear types are analysed. These analytical calculations models are used together with optimisation tools in order to improve the performance of investigated magnetic gear types. Experimental test gears are designed to validate...... is searched and only a single reference [74] is found and that is why the combination of a cycloidal gear and a magnetic gear are considered as an innovative supplement to magnetic gear technology. A magnetic cycloidal gear is designed with a gearing of 1:21 and a calculated active torque density of 142 [Nm...

  11. High Pressure Angle Gears: Comparison to Typical Gear Designs

    Science.gov (United States)

    Handschuh, Robert F.; Zabrajsek, Andrew J.

    2010-01-01

    A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

  12. Double Helical Gear Performance Results in High Speed Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  13. Frictional Effects on Gear Tooth Contact Analysis

    OpenAIRE

    Zheng Li; Ken Mao

    2013-01-01

    The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented us...

  14. Review of Composite Asymmetric Spur Gear

    OpenAIRE

    Sandeep C. Dhaduti; Dr. S. G. Sarganachari

    2015-01-01

    Gears made from composite materials are widely used in many power and motion transmission applications. Due to lower weight to stiffness ratio, composite gears may be replaced by conventional material gears in power transmission systems. Design of gears with asymmetric teeth enables to increase load capacity, reduce weight, size and vibration level. This article includes a summary of asymmetric gear design parameters, new developments of asymmetric spur gear and their ...

  15. Precise low cost chain gears for heliostats

    Science.gov (United States)

    Liedke, Phillip; Lewandowski, Arkadiusz; Pfahl, Andreas; Hölle, Erwin

    2016-05-01

    This work investigates the potential of chain gears as precise and low cost driving systems for rim drive heliostats. After explaining chain gear basics the polygon effect and chain lengthening are investigated. The polygon effect could be measured by a heliostat with chain rim gear and the chain lengthening with an accordant test set up. Two gear stages are scope of this work: a rim gear and an intermediate gear. Dimensioning, pretensioning and designing for both stages are explained.

  16. Sports Injuries

    Science.gov (United States)

    ... sometimes you can injure yourself when you play sports or exercise. Accidents, poor training practices, or improper ... can also lead to injuries. The most common sports injuries are Sprains and strains Knee injuries Swollen ...

  17. Sport and Transgender People: A Systematic Review of the Literature Relating to Sport Participation and Competitive Sport Policies.

    Science.gov (United States)

    Jones, Bethany Alice; Arcelus, Jon; Bouman, Walter Pierre; Haycraft, Emma

    2017-04-01

    Whether transgender people should be able to compete in sport in accordance with their gender identity is a widely contested question within the literature and among sport organisations, fellow competitors and spectators. Owing to concerns surrounding transgender people (especially transgender female individuals) having an athletic advantage, several sport organisations place restrictions on transgender competitors (e.g. must have undergone gender-confirming surgery). In addition, some transgender people who engage in sport, both competitively and for leisure, report discrimination and victimisation. To the authors' knowledge, there has been no systematic review of the literature pertaining to sport participation or competitive sport policies in transgender people. Therefore, this review aimed to address this gap in the literature. Eight research articles and 31 sport policies were reviewed. In relation to sport-related physical activity, this review found the lack of inclusive and comfortable environments to be the primary barrier to participation for transgender people. This review also found transgender people had a mostly negative experience in competitive sports because of the restrictions the sport's policy placed on them. The majority of transgender competitive sport policies that were reviewed were not evidence based. Currently, there is no direct or consistent research suggesting transgender female individuals (or male individuals) have an athletic advantage at any stage of their transition (e.g. cross-sex hormones, gender-confirming surgery) and, therefore, competitive sport policies that place restrictions on transgender people need to be considered and potentially revised.

  18. A new era in sports science: the launch of BMC Sports Science, Medicine and Rehabilitation.

    Science.gov (United States)

    Moylan, Elizabeth C; Horne, Genevieve

    2013-03-28

    This Editorial celebrates the launch of BMC Sports Science, Medicine and Rehabilitation within the BMC series of journals published by BioMed Central. BMC Sports Science, Medicine and Rehabilitation incorporates the recently closed Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology (SMARTT) with an expanded scope and Editorial Board. BMC Sports Science, Medicine and Rehabilitation will fill its own niche in the BMC series alongside other companion journals including BMC Physiology, BMC Musculoskeletal Disorders and BMC Surgery.

  19. Torque-Splitting Gear Drive

    Science.gov (United States)

    Kish, J.

    1991-01-01

    Geared drive train transmits torque from input shaft in equal parts along two paths in parallel, then combines torques in single output shaft. Scheme reduces load on teeth of meshing gears while furnishing redundancy to protect against failures. Such splitting and recombination of torques common in design of turbine engines.

  20. Gear Defect Modeling of a Multiple-Stage Gear Train

    Directory of Open Access Journals (Sweden)

    Andrew Sommer

    2011-01-01

    Full Text Available This study demonstrates the transient and steady state dynamic loading on teeth within a two-stage gear transmission arising from backlash and geometric manufacturing errors by utilizing a nonlinear multibody dynamics software model. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. Torsional vibration is shown to cause teeth separation and double-sided impacts in unloaded and lightly loaded gearing drives. Vibration and impact force distinctions between backlash and combinations of transmission errors are demonstrated under different initial velocities and load conditions. The backlash and manufacturing errors in the first stage of the gear train are distinct from those of the second stage. By analyzing the signal at a location between the two stages, the mutually affected impact forces are observed from different gear pairs, a phenomenon not observed from single pair of gears. Frequency analysis shows the appearance of side band modulations as well as harmonics of the gear mesh frequency. A joint time-frequency response analysis during startup illustrates the manner in which contact forces increase during acceleration.

  1. [Sport medicine].

    Science.gov (United States)

    Epstein, Yoram

    2012-02-01

    It is only since the late 20th century that Sport and Exercise Medicine has emerged as a distinct entity in health care. In Israel, sports medicine is regulated by a State Law and a sport physician is certified after graduating a structured program. In the past, sports medicine was related to the diagnosis and treatment of injuries encountered by top athletes. In recent years, the scope of sport medicine has broadened to reflect the awareness of modern society of the dangers of physical inactivity. In this perspective the American College of Sport Medicine (ACSM) recently launched a program--"Exercise is Medicine", to promote physical activity in order to improve health and well-being and prevention of diseases through physical activity prescriptions. This program is from doctors and healthcare providers, adjusted to the patient or trainee. The sport physician does not replace a medical specialist, but having a thorough understanding about the etiology of a sport-related injury enables him to better focus on treatment and prevention. Therefore, Team Physicians in Elite Sport often play a role regarding not only the medical care of athletes, but also in the physiological monitoring of the athlete and correcting aberrations, to achieve peak physical performance. The broad spectrum of issues in sport and exercise medicine cannot be completely covered in one issue of the Journal. Therefore, the few reports that are presented to enhance interest and understanding in the broad spectrum of issues in sports and exercise medicine are only the tip of the iceberg.

  2. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and...

  3. 29 CFR 1918.54 - Rigging gear.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  4. Tooth bending fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1996-09-01

    Full Text Available A gear is a machine element designed to transmit force and motion from one mechanical unit to another. The design and function of gears are usually closely associated, since gears are designed for a specific function. Various types of gears have...

  5. Cardan gear mechanism versus slider-crank mechanism in pumps and engines

    Energy Technology Data Exchange (ETDEWEB)

    Karhula, J.

    2008-07-01

    In machine design we always want to save space, save energy and produce as much power as possible. We can often reduce accelerations, inertial loads and energy consumption by changing construction. In this study the old cardan gear mechanism (hypocycloid mechanism) has been compared with the conventional slider-crank mechanism in air pumps and four-stroke engines. Comprehensive Newtonian dynamics has been derived for the both mechanisms. First the slidercrank and the cardan gear machines have been studied as lossless systems. Then the friction losses have been added to the calculations. The calculation results show that the cardan gear machines can be more efficient than the slider-crank machines. The smooth running, low mass inertia, high pressures and small frictional power losses make the cardan gear machines clearly better than the slider-crank machines. The dynamic tooth loads of the original cardan gear construction do not rise very high when the tooth clearances are kept tight. On the other hand the half-size crank length causes high bearing forces in the cardan gear machines. The friction losses of the cardan gear machines are generally quite small. The mechanical efficiencies are much higher in the cardan gear machines than in the slider-crank machines in normal use. Crankshaft torques and power needs are smaller in the cardan gear air pumps than in the equal slider-crank air pumps. The mean crankshaft torque and the mean output power are higher in the cardan gear four-stroke engines than in the slider-crank four-stroke engines in normal use. The cardan gear mechanism is at its best, when we want to build a pump or an engine with a long connecting rod (approx 5.crank length) and a thin piston (approx 1.5.crank length) rotating at high angular velocity and intermittently high angular acceleration. The cardan gear machines can be designed also as slide constructions without gears. Suitable applications of the cardan gear machines are three-cylinder half

  6. Sport and transgender people: a systematic review of the literature relating to sport participation and competitive sport policies

    OpenAIRE

    Jones, Bethany Alice; Arcelus, Jon; Bouman, Walter Pierre; Haycraft, Emma

    2016-01-01

    Background\\ud \\ud Whether transgender people should be able to compete in sport in accordance with their gender identity is a widely contested question within the literature and among sport organisations, fellow competitors and spectators. Owing to concerns surrounding transgender people (especially transgender female individuals) having an athletic advantage, several sport organisations place restrictions on transgender competitors (e.g. must have undergone gender-confirming surgery). In add...

  7. Bispectrum Analysis in Fault Diagnosis of Gears

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The application of bispectrum analysis in fault diagnosis of gears is studied in this paper. Bispectrum analysis is capable of removing Gaussian or symmetric non-Gaussian noise and providing more information than power spectrum analysis. The results of the research show that normal gear signals, cracked gear signals and broken gear signals can be easily distinguished by using bispectrum as the signal features. The bispectrum diagonal slice Bx(ω1,ω2) can be used to identify the gear condition automatically.

  8. Optimization of compound gear pump

    Institute of Scientific and Technical Information of China (English)

    栾振辉

    2002-01-01

    This paper introduces the performances of compound gear pump. Based on the target of having the smallest mass per unit volume, the paper established a mathematical model of optimization, and obtained the results of optimization of the pump.

  9. Gear geometry of cycloid drives

    Institute of Scientific and Technical Information of China (English)

    CHEN BingKui; FANG TingTing; LI ChaoYang; WANG ShuYan

    2008-01-01

    According to differential geometry and gear geometry,the equation of meshing for small teeth difference planetary gearing and a universal equation of conjugated profile are established based on cylindrical pin tooth and given motion.The correct meshing condition,contact line,contact ratio,calculating method for pin tooth's maximum contact point are developed.Investigation on the theory of conjugated meshing is carried out when the tooth difference numbers between pin wheel and cycloidal gear are 1,2,3 and -1,respectively.A general method called enveloping method to generate hypocycloid and epicycloid is put forward.The correct mesh-ing condition for cycloid pin wheel gearing is provided,and the contact line and the contact ratio are also discussed.

  10. Gear geometry of cycloid drives

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    According to differential geometry and gear geometry, the equation of meshing for small teeth difference planetary gearing and a universal equation of conjugated profile are established based on cylindrical pin tooth and given motion. The correct meshing condition, contact line, contact ratio, calculating method for pin tooth’s maximum contact point are developed. Investigation on the theory of conjugated meshing is carried out when the tooth difference numbers between pin wheel and cycloidal gear are 1, 2, 3 and ?1, respectively. A general method called enveloping method to generate hypocycloid and epicycloid is put forward. The correct meshing condition for cycloid pin wheel gearing is provided, and the contact line and the contact ratio are also discussed.

  11. Eye Injuries in Sports

    Science.gov (United States)

    ... in Sports Which sports cause the most eye injuries?Sports cause more than 40,000 eye injuries each ... and racquet sports.When it comes to eye injuries, sports can be classified as low risk, high risk ...

  12. Teaching Sport as History, History through Sport

    Science.gov (United States)

    Wheeler, Robert F.

    1978-01-01

    Describes an undergraduate history course based on two themes: sport as a reflection of society and sport as a socializing agent affecting society. The course focuses on sports and industrialization, traditional and modern sports, political and economic aspects of sport, and inequality and discrimination in sports. (Author/JK)

  13. analysis of gear milling at vari gear milling at various gear milling at ...

    African Journals Online (AJOL)

    eobe

    K. A. Oladejo. 1DEPARTMENT OF MECHANICAL ... commonly used gears for mechanical power transmission. Form .... developed an algorithm for the design of a system for selecting ..... Optimization for minimizing production Time of. Turning ...

  14. A study of the optimum configuration of injection molded plastic gear by modification of gear tooth

    Science.gov (United States)

    Lee, Dae-Suep; Kwon, Young-Doo; Doc, Jin-Uk; Leed, Jun-Hyuk

    2009-07-01

    In this study, the gear system is optimized by modifying the tooth configuration of the plastic gears. Plastic gear is widely used as a machine element in industries of electric and electronic parts, automotive parts etc. Unlike the steel gear, the plastic gear has low load- transmission, durability and reliability. On the other hand, it is light-weight, low-noise, operable without a lubricant, shock absorptive, and anti-corrosive. The gear characteristics are calculated and analyzed by Hexagon and FEM (Finite Element Method) tools, and the characteristics of the standard gear and the addendum modified gear of the steel gear and the plastic gear are compared. When torque is applied to these gear systems, the system using the addendum modified gear can realize soft contact between gears. So, the noise of the addendum modified gear system was less than that of the common normal gear system. However, this is not applicable to any material, such as steel which is governed by DIN (Deuteshe Industrie Norm) recommendation. This study adopted the narrow tip tooth plastic gear, and proposed the optimum addendum modified gear with respect to stress, noise and contact ratio. To calculate and analyze the simulation of gear matching, we used commercial tools like CATIA, Auto-CAD, MARC for simulation and Hexagon for calculation.

  15. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Centers Broken Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries Joint Replacement Rehabilitation ...

  16. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Ankle Neck & Back Health Centers Broken Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries ...

  17. Sports Medicine

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2004-01-01

    Sports medicine has become one of the biggest and fastest growing medical fields in recent years. That is because sports have become a major part of most societies. As work becomes more stressful (紧张的,压力重

  18. Sports Physicals

    Science.gov (United States)

    ... Prepare for Your Sports Season Choosing the Right Sport for You Contact Us Print Resources Send to a Friend Permissions Guidelines Note: Clicking these links will take you to a site outside of KidsHealth's control. About TeensHealth Nemours.org Reading ...

  19. Sport Toekomstverkenning

    NARCIS (Netherlands)

    Marieke van Bakel; Ine Pulles; Annet Tiessen-Raaphorst; Frank den Hertog; Robert Vonk; Casper Schoemaker

    2017-01-01

    Deze publicatie verschijnt enkel digitaal op www.sporttoekomstverkenning.nl. Welke maatschappelijke veranderingen beïnvloeden de sport in Nederland? Waar gaat het heen met de sport tussen nu en 2040? Welke kansen, maar ook keuzes biedt dit voor de sportsector en het sportbeleid? Deze vragen

  20. Sports Physicals

    Science.gov (United States)

    ... more specific about athletic issues. During a regular physical, however, your doctor will address your overall well-being, which may include things that are unrelated to sports. You can ask your doctor to give you both types of ... if your sports physical exam doesn't reveal any problems, it's always ...

  1. Sports Nutrition.

    Science.gov (United States)

    Missouri State Dept. of Health, Jefferson City.

    This guide deals with various aspects of sports and nutrition. Twelve chapters are included: (1) "Sports and Nutrition"; (2) "Eat to Compete"; (3) "Fit Folks Need Fit Food"; (4) "The Food Guide Pyramid"; (5) "Fat Finder's Guide"; (6) "Pre- and Post-Event Meals"; (7) "Tips for the…

  2. Paralympic Sports

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The sport movement for persons with a disability has changed dramatically over the last dec- ades with even more changes ahead.Public awareness has increased.More and more individuals with a disability of all ages find interest in sport.

  3. Sport Management.

    Science.gov (United States)

    Parkhouse, Bonnie L., Ed.; And Others

    1984-01-01

    Traditional teaching and coaching positions have become scarce but the expanding field of sport management has created its own job market, demanding new skills and preparation. Three articles are offered that explore different aspects and possibilities for a sport management career. (DF)

  4. STRESS FRACTURES IN SPORT

    Directory of Open Access Journals (Sweden)

    Đivo Ban

    2009-11-01

    Full Text Available Children and adolescents today, all before starting with regular sports activities and involvement in semi-professional and top professional sport, so it increases the num- ber of discovered stress fractures in this age. This type of injury can occur as a consequence of action one strong force, or the many repeated small force strength, to be exact, when the load (stress transcend ability reparations bones. Stress fractures are recorded and described up to the lower limbs. Research has been confirmed that the bones of lower leg are mostly made in injury, and with the el- derly and with the population of children and young adolescents. Occur in many sports, something to them is greater when the frequency of running and often are present in the female population. According to the results of numerous investigations, mistakes in the training are the most common cause of the emergence of stress fracture. In a direct comparison with complemented these injuries is the condition of muscles, so it is important that at the sa- me time carry out exercises strengthen muscles and stretching. Typical clinical signs of stress fractures are localized painful sensitivity to palpa- tion and runoff in a small number of cases. The basic diagnostic procedure is a medical check, it is the small, radiology and scintigraphyc diagnostics (most accurate and mag- netic resonance imaging. Treatment is usually without surgery and conservative, with rest and reducing stress, and its activity athlete breaks mainly between four and eight weeks. Only the very need surgical treatment The most important thing is that attention is focused on the proper prevention and to take all that it ever occurred to stress fractures that athletes ramble of the courts and the competition (better education of sports workers, separation of groups with increa- sed risk of the formation of an injury, adaptation activities age and abilities of athletes, adequate sports equipment, high-quality sports

  5. Proposal of an Axial Gap Magnetic Gear

    Science.gov (United States)

    Hirata, Katsuhiro; Yamamoto, Masafumi; Muramatsu, Masari

    Magnetic gears have some benefits such as low noise, low vibration, and they are maintenance free as opposed to mechanical gears. In the view of these advantages, some high-performance magnetic gears have been proposed; however, these gears have a complex structure because they require several magnets. In this paper, we propose a new magnetic gear with a high reduction ratio comprising only two magnets. From the result of 3D-FE analysis, it was found that our model generated large transmitted torque and less cogging torque despite its thin compact size. This result shows the possibility of the application of the proposed gear in various industries.

  6. Design and construction of permanent magnetic gears

    OpenAIRE

    Jørgensen, Frank Thorleif

    2010-01-01

    This thesis deals with design and development of permanent magnetic gears. The goal of this thesis is to develop knowledge and calculation software for magnetic gears. They use strong NdFeB permanent magnets and a new magnetic gear technology, which will be a serious alternative to classical mechanical gears. The new magnetic gear will have a high torque density1 relationship –high efficiency and are maintenance free. In this project was manufactured two test gears which is tested and verifie...

  7. Theory of gearing kinematics, geometry, and synthesis

    CERN Document Server

    Radzevich, Stephen P

    2012-01-01

    The first book of its kind, Theory of Gearing: Kinematics, Geometry, and Synthesis systematically develops a scientific theory of gearing that makes it possible to synthesize novel gears with the desired performance. Written by a leading gearing expert who holds more than 200 patents, it presents a modern methodology for gear design. The proposed theory is based on a key postulate: all the design parameters for an optimal gear pair for a particular application can be derived from (a) a given configuration of the rotation vectors of the driving and driven shafts and (b) the power transmitted by

  8. Flex-gear power transmission system for transmitting EMF between Sun and ring gears

    Science.gov (United States)

    Vranish, John M. (Inventor)

    1994-01-01

    A plurality of flexible cylindrical members, termed flex-gears and having gear tooth type perimeters are located in an annular space between two concentric rotating gear members, one an inner gear member and the other an outer ring gear member, both of which have mutually facing toothed surfaces which engage the flex-gears. The flex-gears rotate and orbit around the annular space as planetary gears when the inner and outer gear members rotate with respect to one another. Pairs of these elements located in two mutually parallel planes and separated by insulators provide two electrical conductor paths across which an electrical signal source, AC or DC, can be connected and coupled to an electrical device. Alternatively, one set of elements including outer gears segmented into mutually insulated semicircles and inner gears segmented into mutually insulated quadrants can be used.

  9. Investigation into nitrided spur gears

    Energy Technology Data Exchange (ETDEWEB)

    Yilbas, B.S.; Coban, A.; Nickel, J.; Sunar, M.; Sami, M.; Abdul Aleem, B.J. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)

    1996-12-01

    The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6Al-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.

  10. Investigation into nitrided spur gears

    Science.gov (United States)

    Yilbas, B. S.; Coban, A.; Nickel, J.; Sunar, M.; Sami, M.; Aleem, B. J. Abdul

    1996-12-01

    The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6A1-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.

  11. Rapportage sport 2008

    NARCIS (Netherlands)

    Koen Breedveld; Carlijn Kamphuis; Annet Tiessen-Raaphorst

    2008-01-01

    Sport boeit. Sport bindt. Sport bevordert de gezondheid. En sport betaalt. Sport is anno 2008 ongekend populair. Tweederde van de Nederlanders doet aan sport. Na zwemmen en fietsen is fitness de meest populaire sport geworden. Daarnaast zetten anderhalf miljoen Nederlanders zich als vrijwilliger

  12. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Teens Search Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español Making a Change – Your Personal Plan Hot Topics Poison Ivy Who Can Get Weight Loss Surgery? Choosing the Right Sport for You Shyness A ...

  13. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Español Making a Change – Your Personal Plan Hot Topics Poison Ivy Who Can Get Weight Loss Surgery? ... Teens For Kids For Parents MORE ON THIS TOPIC Nutrition & Fitness Center Sports Physicals Figuring Out Fat ...

  14. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries ... Your doctor will outline a program to help prevent the development of blood clots after your surgery. ...

  15. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries ... Your doctor will outline a program to help prevent the development of blood clots after your surgery. ...

  16. Development of a gear vibration indicator and its application in gear wear monitoring

    Science.gov (United States)

    Hu, Chongqing; Smith, Wade A.; Randall, Robert B.; Peng, Zhongxiao

    2016-08-01

    Gear tooth wear is an inevitable phenomenon and has a significant influence on gear dynamic features. Although vibration analysis has been widely used to diagnose localised gear tooth faults, its techniques for gear wear monitoring have not been well-established. This paper aims at developing a vibration indicator to evaluate the effects of wear on gear performance. For this purpose, a gear state vector is extracted from time synchronous averaged gear signals to describe the gear state. This gear state vector consists of the sideband ratios obtained from a number of tooth meshing harmonics and their sidebands. Then, two averaged logarithmic ratios, ALR and mALR, are defined with fixed and moving references, respectively, to provide complementary information for gear wear monitoring. Since a fixed reference is utilised in the definition of ALR, it reflects the cumulated wear effects on the gear state. An increase in the ALR value indicates that the gear state deviates further from its reference condition. With the use of a moving reference, the indicator mALR shows changes in the gear state within short time intervals, making it suitable for wear process monitoring. The efficiency of these vibration indicators is demonstrated using experimental results from two sets of tests, in which the gears experienced different wear processes. In addition to gear wear monitoring, the proposed indicators can be used as general parameters to detect the occurrence of other faults, such as a tooth crack or shaft misalignment, because these faults would also change the gear vibrations.

  17. Sports nutrition

    Directory of Open Access Journals (Sweden)

    Tomanić Milena

    2016-01-01

    Full Text Available Due to higher energy consumption, physically active people have higher nutritional requirements. In addition to other important factors for sports, such as good health and physical predisposition, adequate nutrition is a fundamental component. Sports nutrition must be well planned and individually adapted based on physical characteristics, tendencies towards gaining or losing weight, frequency, duration and intensity of training sessions. Studies have shown that a well-balanced ratio of macro and micronutrients, with the support of supplements and adequate hydration, can significantly improve athletic performance and plays a key role in achieving better results. An optimally designed nutritional program, with realistic and achievable goals, which complements a well-planned training program, is the basis for success in sports. Only when nutritional requirements are met, deficits can be prevented and performance in sport pushed to the limit.

  18. Research on stepless transmission utilizing noncircular gears

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmiss...

  19. Computer simulation of gear tooth manufacturing processes

    Science.gov (United States)

    Mavriplis, Dimitri; Huston, Ronald L.

    1990-01-01

    The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

  20. Advanced theories of hypoid gears

    CERN Document Server

    Wang, Xudong

    2013-01-01

    In order to develop more efficient types of gears, further investigation into the theories of engagement is necessary. Up until now most of the research work on the theories of engagement has been carried out separately on different groups, and based on individual types of profiles. This book aims at developing some universal theories, which can not only be used for all types of gears, but can also be utilized in other fields such as sculptured surfaces. The book has four characteristics: the investigations are concentrated on mismatched tooth surfaces; all the problems are dealt with from a

  1. Sports fractures.

    OpenAIRE

    DeCoster, T. A.; Stevens, M. A.; Albright, J. P.

    1994-01-01

    Fractures occur in athletes and dramatically influence performance during competitive and recreational activities. Fractures occur in athletes as the result of repetitive stress, acute sports-related trauma and trauma outside of athletics. The literature provides general guidelines for treatment as well as a variety of statistics on the epidemiology of fractures by sport and level of participation. Athletes are healthy and motivated patients, and have high expectations regarding their level o...

  2. Sports Accidents

    CERN Multimedia

    Kiebel

    1972-01-01

    Le Docteur Kiebel, chirurgien à Genève, est aussi un grand ami de sport et de temps en temps médecin des classes genevoises de ski et également médecin de l'équipe de hockey sur glace de Genève Servette. Il est bien qualifié pour nous parler d'accidents de sport et surtout d'accidents de ski.

  3. The Casimir Torque on a Cylindrical Gear

    CERN Document Server

    Vaidya, Varun

    2013-01-01

    We utilize Effective Field Theory(EFT) techniques to calculate the casimir torque on a cylindrical gear in the presence of a polarizable but neutral object. We present results for the energy and torque as a function of angle for a gear with multiple cogs, as well as for the case of a concentric cylindrical gear.

  4. Casimir torque on a cylindrical gear

    Science.gov (United States)

    Vaidya, Varun

    2014-08-01

    I utilize effective field theory(EFT) techniques to calculate the Casimir torque on a cylindrical gear in the presence of a polarizable but neutral object and present results for the energy and torque as a function of angle for a gear with multiple cogs, as well as for the case of a concentric cylindrical gear.

  5. 7 CFR 2902.47 - Gear lubricants.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Gear lubricants. 2902.47 Section 2902.47 Agriculture... Gear lubricants. (a) Definition. Products, such as greases or oils, that are designed to reduce... qualifying biobased gear lubricants. By that date, Federal agencies that have the responsibility for...

  6. 46 CFR 28.885 - Cargo gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear shall be marked on the heel of each cargo boom, crane, or derrick. These letters and figures are to...

  7. Modeling of the process of gear shifting in planetary gear trains of motor vehicles

    OpenAIRE

    Aleksandar R. Grkić; Čedomir V. Duboka; Milan M. Krsmanović

    2011-01-01

    Gear boxes, i. e. the realization of their functions, especially gear shift, have a big impact on vehicle operation quality through their effects on the performance of vehicles and their comfort. This paper shows a method of modeling the transition process during gear shifting in planetary gear trains. The simulation model is developed with in order to provide virtual research of planetary gear trains, which would positively decrease the number of real prototypes, thus considerably saving tim...

  8. GEAR UP Aspirations Project Evaluation

    Science.gov (United States)

    Trimble, Brad A.

    2013-01-01

    The purpose of this study was to conduct a formative evaluation of the first two years of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Aspirations Project (Aspirations) using a Context, Input, Process, and Product (CIPP) model so as to gain an in-depth understanding of the project during the middle school…

  9. Negative stiffness in gear contact

    Directory of Open Access Journals (Sweden)

    Půst L.

    2015-12-01

    Full Text Available The tooth contact stiffness is very often included in dynamic mathematical models of gear drives. It is an important value for calculation of torsion eigenfrequencies as well as the dynamic properties of the whole transmission systems. Planetary gear drives have several advantages over simple parallel axis gears, especially due to theirs compact design and great torque-to-weight ratio caused by multiple parallel paths. However, the dimensional or mounting errors can cause that some planets have the tendency to take more load than the others. One of the ways how to improve load sharing is the application of flexible planetary pins or by using a free central wheel. However in such cases, the wheels motion is defined in one rotation coordinate and two translation coordinates — tangential and radial. The reaction force at radial change of axis distance is usually neglected. The focus of this contribution is to derive the stiffness of this radial connection and to analyse the influence of radial stiffness on planetary gear dynamics.

  10. [Sports injuries in German club sports, Aspects of epidemiology and prevention].

    Science.gov (United States)

    Henke, T; Luig, P; Schulz, D

    2014-06-01

    Almost one of four Germans is registered in a sports club. Nowadays, sport is acknowledged as an integral component of a healthy lifestyle. Numerous studies provide evidence of the benefits of sports on health. However, about 2 million sports injuries per year diminish the health benefits of sport. (a) Description of the epidemiology of sports injuries in German sports club between 1987 and 2012 and (b) identification of focal areas for the development and implementation of prevention measures. Continuous questionnaire-based injury monitoring of club sports injuries that have been reported to the respective sports insurance. Full survey among selected federal sports associations. Since 1987, a sample of 200,884 sports injuries has been established. About two thirds of the injuries are reported in soccer, handball, basketball, and volleyball, although only one third of all sports club members are registered in these team sports. The number of women's soccer injuries has risen from 7.5 to 15.6 %. Ankle injuries have decreased from 28.7 to 16.9 %. By contrast, the rate of knee injuries has increased from 18.4 to 20.3 %. Days of disability have dropped steadily since the 1990s. Inpatient hospital days have decreased from 10 to 5 days, whereas the share of injuries that needed surgery increased from 30 to 40 %. Team ball sports are still a clear focal area for injury prevention, as participation and injury risk are highest in this group. While the prevention of ankle injuries seems to be headed in the right direction, knee injuries are increasing. As team ball sports become more popular among women, who are more prone to severe knee injuries, prevention programs should be tailored toward the specific situation and needs of the targeted sports participants.

  11. Sports and Exercise Safety

    Science.gov (United States)

    ... Injuries Sports and Concussions Strains and Sprains Sports Physicals 5 Ways to Prepare for Your Sports Season Handling Sports Pressure and Competition Knee Injuries Runner's Knee Bike Safety Strength Training Dehydration Anterior Cruciate Ligament (ACL) Injuries Medial Collateral ...

  12. Facial Sports Injuries

    Science.gov (United States)

    ... Find an ENT Doctor Near You Facial Sports Injuries Facial Sports Injuries Patient Health Information News media interested in ... should receive immediate medical attention. Prevention Of Facial Sports Injuries The best way to treat facial sports injuries ...

  13. Investigating sport celebrity endorsement and sport event ...

    African Journals Online (AJOL)

    \\' attitudes and the effect of sport event sponsorship and sport ... Results indicate that sport event sponsorship was perceived by participants as a product ... affecting consumers\\' pre-purchase attitudes that may influence buyer behaviour.

  14. TOOTH CONTACT ANALYSIS OF CONICAL INVOLUTE GEARS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mathematical model of conical involute gears is developed based on the theory of gearing and the generating mechanism. Tooth contact analysis (TCA) is performed to examine the meshing and bearing contact of the conical involute gear pairs with intersected and crossed axes. In addition, the principal directions and curvatures of the gear surfaces are investigated and the contact ellipses of the mating tooth surfaces are also studied. Finally, the numerical illustrative examples are provided to demonstrate the computational results, test gears are made for tooth-bearing tests, and the conclusion is verified that the theory has the applicability.

  15. Asymmetric gear rectifies random robot motion

    Science.gov (United States)

    Li, He; Zhang, H. P.

    2013-06-01

    We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.

  16. Research on stepless transmission utilizing noncircular gears

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmission ratio etc. are investigated in detail for each unit. Following this, several examples of using a noncircular gear pair in the units and their manipulation technique are introduced.

  17. Managing Collegiate Sport Clubs.

    Science.gov (United States)

    Matthews, David O., Ed.

    This book is written for the administrators of college sport clubs. It is comprised of a collection of articles on the topics of: (1) Sport Club Administration and Organization; (2) Student Development through Sport Clubs; (3) Sport Club Financing and Fund-Raising; (4) Liability Concerns of Sport Clubs; and (5) Sport Club Program Surveys.…

  18. DESIGN FOR A BI-PLANETARY GEAR TRAIN

    OpenAIRE

    Józef DREWNIAK; Paulina GARLICKA; Aleksandra KOLBER

    2016-01-01

    The article presents the design for a bi-planetary gear train. The project description is supplemented with calculations of kinematics, statics and meshing efficiency of the gear wheels included in the gear train. Excluded are calculations of strength and geometry of gears, shaft and rolling bearing, since they are similar to classical calculations for planetary gears. An assembly drawing in 2D and assembly drawings in 3D of the designed bi-planetary gear train are also shown. This gear train...

  19. KEY TOPICS IN SPORTS MEDICINE

    Directory of Open Access Journals (Sweden)

    Amir Ali Narvani

    2006-12-01

    Full Text Available Key Topics in Sports Medicine is a single quick reference source for sports and exercise medicine. It presents the essential information from across relevant topic areas, and includes both the core and emerging issues in this rapidly developing field. It covers: 1 Sports injuries, rehabilitation and injury prevention, 2 Exercise physiology, fitness testing and training, 3 Drugs in sport, 4 Exercise and health promotion, 5 Sport and exercise for special and clinical populations, 6 The psychology of performance and injury. PURPOSE The Key Topics format provides extensive, concise information in an accessible, easy-to-follow manner. AUDIENCE The book is targeted the students and specialists in sports medicine and rehabilitation, athletic training, physiotherapy and orthopaedic surgery. The editors are authorities in their respective fields and this handbook depends on their extensive experience and knowledge accumulated over the years. FEATURES The book contains the information for clinical guidance, rapid access to concise details and facts. It is composed of 99 topics which present the information in an order that is considered logical and progressive as in most texts. Chapter headings are: 1. Functional Anatomy, 2. Training Principles / Development of Strength and Power, 3. Biomechanical Principles, 4. Biomechanical Analysis, 5. Physiology of Training, 6. Monitoring of Training Progress, 7. Nutrition, 8. Hot and Cold Climates, 9. Altitude, 10. Sport and Travelling, 11. Principles of Sport Injury Diagnosis, 12. Principles of Sport and Soft Tissue Management, 13. Principles of Physical Therapy and Rehabilitation, 14. Principles of Sport Injury Prevention, 15. Sports Psychology, 16. Team Sports, 17. Psychological Aspects of Injury in Sport, 18. Injury Repair Process, 19. Basic Biomechanics of Tissue Injury, 20. Plain Film Radiography in Sport, 21. Nuclear Medicine, 22. Diagnostic Ultrasound, 23. MRI Scan, 24. Other Imaging, 5. Head Injury, 26. Eye

  20. Expansion of epicyclic gear dynamic analysis program

    Science.gov (United States)

    Boyd, Linda Smith; Pike, James A.

    1987-01-01

    The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.

  1. Frictional Effects on Gear Tooth Contact Analysis

    Directory of Open Access Journals (Sweden)

    Zheng Li

    2013-01-01

    Full Text Available The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented using finite element method. Nonlinear finite element model for gear tooth contact with rolling/sliding is then developed. The contact zones for multiple tooth pairs are identified and the associated integration situation is derived. The illustrated bending stress and transmission error results with static and dynamic boundary conditions indicate the significant effects due to the sliding friction between the surfaces of contacted gear teeth, and the friction effect can not be ignored. To understand the particular static and dynamic frictional effects on gear tooth contact analysis, some significant phenomena of gained results will also be discussed. The potentially significant contribution of tooth frictional shear stress is presented, particularly in the case of gear tooth contact analysis with both static and dynamic boundary conditions.

  2. Zero torque gear head wrench

    Science.gov (United States)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  3. Sports Marketing.

    Science.gov (United States)

    Ohio State Dept. of Education, Columbus. Div. of Career-Technical and Adult Education.

    This document presents the Ohio Integrated Technical and Academic Competency profile for sports marketing. The profile is to serve as the basis for curriculum development in Ohio's secondary, adult, and postsecondary programs. The profile includes a comprehensive listing of 999 specialty key indicators for evaluating mastery of 113 competencies in…

  4. Sports Gala

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This year’s 11th National Games saw 21 new world and Asian records set Fans were treated to all the highs and lows of sport during China’s 11th National Games, billed as the country’s mini-Olympics, which witnessed both record-breaking feats and doping

  5. Sports Ballistics

    Science.gov (United States)

    Clanet, Christophe

    2015-01-01

    This review describes and classifies the trajectories of sports projectiles that have spherical symmetry, cylindrical symmetry, or (almost) no symmetry. This classification allows us to discuss the large diversity observed in the paths of spherical balls, the flip properties of shuttlecocks, and the optimal position and stability of ski jumpers.

  6. Sports Nation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China is working to become a global sports power International Olympic Committee President Jacques Rogge watched China’s 11th National Games at Jinan’s stadium in Shandong Province on October 16, 2009. His high-profile attendance has set the

  7. Racket sports.

    Science.gov (United States)

    Jayanthi, Neeru; Esser, Stephen

    2013-01-01

    Tennis may be considered a static and dynamic form of exercise with many well-demonstrated health benefits. Tennis has similar rates of injury to other individual recreational sports and junior competitive sports, without the catastrophic risk of contact/collision sports. Classifying tennis players into junior and elite categories versus adult recreational players may help in outlining volume of play recommendations, exposure risk, and types of injuries. Junior and elite players tend to tolerate higher volumes, have more acute and lower extremity injuries, and have more serious overuse stress injuries. Adult recreational players tend to tolerate lower volumes, have more overuse and upper extremity injuries, and more conditions that are degenerative. Many tennis players also develop asymmetric musculoskeletal adaptations, which may increase risk of specific injury. Tennis-specific evaluations may identify these at-risk segments, help guide preventive strategies including technical errors, and assist in developing return-to-play recommendations. Other racket sports such as squash, badminton, and racquetball have less data available but report both acute and traumatic injuries less commonly seen in tennis.

  8. Sports Fitness

    Science.gov (United States)

    ... motivator. Physically, you need strength and endurance. Your training will vary with your sport. You would not train the same way for pole vaulting as for swimming. You might, however, cross train. Cross training simply means that you include a variety of ...

  9. Racquet Sports.

    Science.gov (United States)

    Zebas, Carole J., Ed.; Groppel, Jack L., Ed.

    1983-01-01

    In six articles on racquet sports, the origins of the games are traced, methods for teaching skills such as footwork, racquetball strategy, and badminton techniques are discussed, and the biomechanics of the one- and two-handed backhand in tennis are reviewed. Information about paddle tennis is included. (PP)

  10. Dudley's handbook of practical gear design and manufacture

    CERN Document Server

    Radzevich, Stephen P

    2012-01-01

    A unique, single source reference for all aspects of gears, Dudley's Handbook of Practical Gear Design and Manufacture, Second Edition provides comprehensive and consistent information on the design and manufacture of gears for the expert and novice alike. The second edition of this industry standard boasts seven new chapters and appendices as well as a wealth of updates throughout. New chapters and expanded topics include: Gear Types and Nomenclature, Gear Tooth Design, Gear Reactions and Mountings, Gear Vibration, The Evolution of the Gear Art, Novikov Gearing and the Inadequacy of the Term,

  11. Reduction of belt CVT gear noise by gear train modification. Optimize vibration characteristics of gear train; Belt CVT no gear noise teigen gijutsu. Gear train shindo tokusei no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Arimatsu, M.; Kawakami, T. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    With the reduction of vehicle noise, the requirements for an efficient method to reduce transmission gear noise have become stronger yearly. So far efforts to reduce gear noise have generally focused on ways of improving the gears themselves. In addition to these traditional methods, it proved very beneficial to us to optimize the gear train structure. Nissan has just released the new Belt CVT for 2.0L Front wheel drive vehicles. We have been analyzing vibration of the gear train by using a finite element model since the early development stage, and we could achieve the quiet gears effectively. 2 refs., 9 figs.

  12. High-torque quiet gear

    Science.gov (United States)

    Moody, Paul E.

    1995-07-01

    A high-torque quiet gear construction consists of an inner hub having a plurality of circumferentially spaced arms extending radially outwardly therefrom, and an outer ring member having a plurality of circumferentially spaced-teeth extending radially inwardly therefrom. The ring member further includes a plurality of gear formations on an outer surface thereof for intermeshing with other gears. The teeth of the ring member are received in spaced relation in corresponding spaces formed between adjacent arms of the hub. An elastomeric member is received in the space formed between the hub and the ring member to form a resilient correction between the arms of the hub and the teeth of the ring member. The side surfaces of the arms and the teeth extend generally parallel to each other and at least partially overlap in a longitudinal direction. The purpose of this configuration is to place the elastomeric member in compression when torque is applied to the hub. Since elastomeric material is relatively incompressible, the result is low shear loads on the adhesive bonds which hold the elastomeric member to both the hub and outer ring member.

  13. Vehicle transmission gear 2009; Getriebe in Fahrzeugen 2009

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    with single dry clutch and electric torque support (G. Hellenbroich); (37) New solutions to increase cost-effectiveness of city bus drive lines with modern automatic powershift transmissions (P. Wunderlich); (38) Evaluation of the gearchanging comfort at commercial vehicles (W. Wessel); (39) New structure-optimised transmission systems for advanced commercial vehicles (R. Resch); (40) Depth of details of powertrain models for depocting driveability effects (F. Matthies); (41) A nonlinear transmission approach for dual mass flywheels (C. Benatzky); (42) Clattering and rattling is still a challenge for vehicle transmission developers (M. Dally); (43) Study on the effect of driving cycles on energy efficiency of electric vehicles (J. Fenzhu); (44) Modular modelling and simulation of hybrid power trains (G. Kelz); (45) The integration of electrical axle drives in hybrid vehicle and electric vehicles (H. Schaefer); (46) Energy balance of the optimized CVT hybrid driveline (B.-R. Hoehm); (47) Functional efficiency comparison between split- and parallel-hybrid using advanced energy flow analysis methods (P. Guttenberg); (48) Simulation of the fuel consumption benefits of various transmission arrangements and control strategies within a flywheel based mechanical hybrid system (W. Body); (49) Ideal test specifications for transmissions (T. Kassel); (50) The 'Hybrid Effect': Influence of hybridisation on the durability of automatic transmissions (T. Lavall); (51) Schaeffler lightweight differentials (R. Malik); (52) Integrated all wheel drive in the ZF eight-speed automatic gear (D. Baasch); (53) Optimized structures for amplifying torque vectoring systems (A. Sue); (54) The new sport differential in the Audi S4 (U. Pinschmidt).

  14. 29 CFR 1919.19 - Gear requiring welding.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  15. 50 CFR 697.23 - Restricted gear areas.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Restricted gear areas. 697.23 Section 697... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed...) Restricted Gear Area I—(1) Duration—(i) Mobile Gear. From October 1 through June 15 of each fishing year,...

  16. Effects of gear box vibration and mass imbalance on the dynamics of multistage gear transmission

    Science.gov (United States)

    Choy, F. K.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, D. P.

    1991-01-01

    The dynamic behavior of multistage gear transmission system, with the effects of gear-box-induced vibrations and rotor mass-imbalances is analyzed. The model method, using undamped frequencies and planar mode shapes, is used to reduce the degree-of-freedom of the system. The various rotor-bearing stages as well as lateral and torsional vibrations of each individual stage are coupled through localized gear-mesh-tooth interactions. Gear-box vibrations are coupled to the gear stage dynamics through bearing support forces. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domain. A typical three-staged geared system is used as an example. Effects of mass-imbalance and gear box vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  17. Pneumatic, PLC Controlled, Automotive Gear Shifting Mechanism

    Directory of Open Access Journals (Sweden)

    Muntaser Momani

    2010-05-01

    Full Text Available In this study, a gear shifting mechanism was designed and applied to make the shifting process faster and less destructible for the driver. The new device must be reliable, has a small dimensions, low construction and maintenance cost. This paper aims to improve gear shifting process using devices as: a manual four speed gear box, four pneumatic double acting cylinders, four pneumatic two position five ways directional control valves, Programmable Logic Controller (PLC LOGO unit, an electrical motor, an electrical clutch, a belt, two pulleys, limit switches, push buttons, bulbs, a table (holder and power supply. According to suggested gear_ shifting method the driver can select the transmission gear ratio without moving his hands from the steering wheel by putting the gear shifting push buttons on the steering wheel. Using this method leaves to the driver the excitement of choosing the shifting moment.

  18. Topological and parametric optimization of gear trains

    Science.gov (United States)

    Swantner, Albert; Campbell, Matthew I.

    2012-11-01

    A method for automating the design of gear trains comprised of simple, compound, bevel and worm is described. The search process combines topological changes, discrete variable choices and continuous variable optimization. By combing best-first search, implicit enumeration, automated optimization invocation and gradient-based optimization, a near guarantee of the optimal solution can be made. While the combination of methods is specific to gear trains, there are aspects of the work that make it amenable to other engineering design problems. In addition, the topological and discrete modifications to the candidate solutions are specific to gear trains, but the graph grammar methodology that is adopted has been tailored to other problems. This article presents details on the rules that generate feasible gear trains, the evaluation routines used in determining the objective functions and constraints, and the interaction among the three search methods. Resulting gear trains are presented for a variety of gear problems.

  19. Optical gears in a nanophotonic directional coupler

    CERN Document Server

    Zhang, Fengchun; Zhang, Heran; Zhang, Yong; Huang, Xu-Guang; Jia, Baohua; Liu, Songhao

    2016-01-01

    Gears are rotating machines, meshing with each other by teeth to transmit torque. Interestingly, the rotating directions of two meshing gears are opposite, clockwise and counterclockwise. Although this opposite handedness motion has been widely investigated in machinery science, the analogue behavior of photons remains undiscovered. Here, we present a simple nanophotonic directional coupler structure which can generate two meshing gears of angular momentum (AM) of light, optical gears. Due to the abrupt phase shift effect and birefringence effect, the AM states of photons vary with the propagation distance in two adjacent waveguides of the coupler. Thus, by the choice of coupling length, it is able to obtain two light beams with opposite handedness of AM, confirming the appearance of optical gears. The full control in the handedness of output beams is achieved via tuning the relative phase between two orthogonal modes at the input ports. Optical gears thus offer the possibility of exploring light-matter inter...

  20. Tool Gear: Infrastructure for Parallel Tools

    Energy Technology Data Exchange (ETDEWEB)

    May, J; Gyllenhaal, J

    2003-04-17

    Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.

  1. Management of sport-related maxillofacial injuries.

    Science.gov (United States)

    Roccia, Fabio; Diaspro, Alberto; Nasi, Andrea; Berrone, Sid

    2008-03-01

    By analyzing sports-related maxillofacial fractures, we sought to describe preventive measures and recovery times until sporting activities could be resumed. Between January 2001 and December 2006, 1241 patients were hospitalized as a result of maxillofacial fractures. The patients with sports-related maxillofacial fractures were analyzed based on age, sex, type of sport, injury mechanism, trauma site, presence of associated fractures, hospitalization, treatment method, and recovery time until the resumption of sporting activities. One hundred thirty-eight patients (11.4%) sustained sports-related maxillofacial fractures: 121 males and 17 females (ratio 8:1), aged between 11 and 72 years. The sport producing the greatest number of injuries was soccer (62.3%), followed by skiing (14.5%), and horseback riding (6.5%). The injuries involved mainly the middle third of the face (71.6%), and the mandible was the most affected site (27.2%), followed by the maxillary-zygomatic-orbital complex (25.9%). Treatment was surgery in 93.5% of the patients, with an average hospitalization period of 3.5 days. The protocol created to manage the follow-up of maxillofacial injury patients advised resuming sports activities at least 40 days after the trauma, except in the case of combat sports, when a period of 3 months was required. Although the results of this study indicate a reduction in the total incidence of sports-related maxillofacial injuries, they also show an alarming secondary increase in trauma resulting from the most popular sport in Italy-soccer. Therefore, stricter regulations are needed to discourage violent play, rather than relying on the use of protective equipment. Moreover, patients should be advised when they can resume sports activities, particularly in the case of professionals and semiprofessionals.

  2. NEW DESIGN METHOD FOR HYPOID GEARS

    Institute of Scientific and Technical Information of China (English)

    Su Zhijiang; Wu Xutang; Mao Shimin

    2005-01-01

    A digital model is presented for the purpose of design, manufacture and measurement of hypoid gear, based on the non-uniform rational B-spline surface (NURBS) method. The digital model and the function-oriented active design technique are combined to form a new design method for hypoid gears. The method is well adaptable to CNC bevel gear cutting machines and CNC-controlled gear inspection machines, and can be used to create the initial machine tool cutting location data or program measurement path. The presented example verifies the method is correct.

  3. Gear Noise and Vibration : A Literature Survey

    OpenAIRE

    Åkerblom, Mats

    2001-01-01

    This paper is a survey of the literature on gear noise and vibration. It is divided into three parts, “Transmission error”, “Dynamic models” and “Noise and vibration measurement”. Transmission error (TE) is considered to be an important excitation mechanism for gear noise and vibration. The definition of transmission error is “The difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate”. Dynamic models of the system...

  4. Evaluation of Carburized and Ground Face Gears

    Science.gov (United States)

    Lewicki, David G.; Handschuh, Robert F.; Heath, Gregory F.; Sheth, Vijay

    1999-01-01

    Experimental durability tests were performed on carburized and ground AIS19310 steel face gears. The tests were in support of a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP) to enhance face-gear technology. The tests were conducted in the NASA Glenn spiral-bevel-gear/face-gear test facility. Tests were run at 2300 rpm face gear speed and at loads of 64, 76, 88, 100, and 112-percent of the design torque of 377 N-m (3340 in-lb). The carburized and ground face gears demonstrated the required durability when run for ten-million cycles at each of the applied loads. Proper installation was critical for the successful operation of the spur pinions and face gears. A large amount of backlash produced tooth contact patterns that approached the inner-diameter edge of the face-gear tooth. Low backlash produced tooth contact patterns that approached the outer-diameter edge of the face-gear tooth. Measured backlashes in the range of 0.178 to 0.254 mm (0.007 to 0.010 in) produced acceptable tooth contact patterns.

  5. Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

    Science.gov (United States)

    Mo, Shuai; Zhang, Yidu; Wu, Qiong; Wang, Feiming; Matsumura, Shigeki; Houjoh, Haruo

    2017-07-01

    Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.

  6. Development of austempered ductile iron timing gears; Austemper kyujo kokuen chutetsu timing gear no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Yamamoto, S.; Numajiri, S.; Nakajima, K. [Mitsubishi Motors Corp., Tokyo (Japan)

    1996-05-01

    To reduce vibration and noise of gears compared with ordinary steel gears for four cycle diesel engine of small commercial vehicles, austempered ductile iron (ADI) gears have been developed, which have excellent mechanical properties and vibration damping properties equivalent to steel gears. ADI is a material with tensile strength of 1,000 MPa, which is made by austempering the ductile iron to change matrix texture into tough bainite. For a new process method of ADI gears, austempering is conducted after gear cutting, and shaving is conducted, finally. Gear materials before austempering can be smoothly machined without deteriorating their machinability, to produce highly accurate gears. Fifteen percent of noise can be reduced for ADI gears during idling of engine, where 0.7 dB can be reduced in the noise level. The ADI gears provide superior pitting resistance to ordinary steel gears. They have nearly equivalent dedendum bending fatigue strength to ordinary soft nitrided steel gears. 6 refs., 12 figs., 2 tabs.

  7. Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

    Science.gov (United States)

    Mo, Shuai; Zhang, Yidu; Wu, Qiong; Wang, Feiming; Matsumura, Shigeki; Houjoh, Haruo

    2017-03-01

    Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.

  8. Report on Sport 2003

    NARCIS (Netherlands)

    Koen Breedveld; Rob Goossens; Maarten van Bottenburg; Wil Ooijendijk; Vincent Hildebrandt; Maarten Stiggelbout; Jo Lucassen; Hugo van der Poel

    2003-01-01

    Original title: Rapportage Sport 2003. There has been a huge increase in the interest in sport in recent decades. The number of people taking part in sport has grown strongly and more sport is broadcast on television than ever before. The government has invested a great deal in sport, not least bec

  9. Sport for life

    NARCIS (Netherlands)

    Annet Tiessen-Raaphorst; Desiree Verbeek; Jos de Haan; Koen Breedveld

    2010-01-01

    Original title: Sport: een leven lang. Many Dutch people are involved in sport: by participating themselves, performing voluntary work for a sports club, following the sporting achievements of others via the media or attending sporting events. In this report we look at each of these forms of involv

  10. Optimum Weight Design of Functionally Graded Material Gears

    Institute of Scientific and Technical Information of China (English)

    JING Shikai; ZHANG He; ZHOU Jingtao; SONG Guohua

    2015-01-01

    Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculiar to the gear, there will be large amounts of design parameters in gear design, and the influences of gear parameters changing on gear trains, transmission system and the whole equipment have to be taken into account, which increases the complexity of optimization problem. This paper puts forward to apply functionally graded materials (FGMs) to gears and then conduct the optimization. According to the force situation of gears, the material distribution form of FGM gears is determined. Then based on the performance parameters analysis of FGMs and the practical working demands for gears, a multi-objective optimization model is formed. Finally by using the goal driven optimization (GDO) method, the optimal material distribution is achieved, which makes gear weight and the maximum deformation be minimum and the maximum bending stress do not exceed the allowable stress. As an example, the applying of FGM to automotive transmission gear is conducted to illustrate the optimization design process and the result shows that under the condition of keeping the normal working performance of gear, the method achieves in greatly reducing the gear weight. This research proposes a FGM gears design method that is able to largely reduce the weight of gears by optimizing the microscopic material parameters instead of changing the macroscopic dimension parameters of gears, which reduces the complexity of gear weight optimization problem.

  11. Involute Spur Gear Template Development by Parametric Technique ...

    African Journals Online (AJOL)

    ... Gear Template Development by Parametric Technique Using Computer Aided Design. ... cylindrical coordinate systems to create the involute curve profile. Since spur gear geometry is controlled by a few basic parameters, a generic gear

  12. Interfacing Sport

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    these media (expressiveness, reflexivity, identity), or ar media making us run (nudging, persuasion, societal benefits). The study includes theory on interactivity, media sociology, followed by cases (twitter and personal branding, selftracking and selfreflexivity, social media and club organization, fandom......This study tries to map out the possible interplay between interactive digital media (including mobile and wearable technologies) and sport as performance and participation. The ambition is to create a model providing the analytical framework for understanding questions like "are we running...

  13. New Gear Transmission Error Measurement System Designed

    Science.gov (United States)

    Oswald, Fred B.

    2001-01-01

    The prime source of vibration and noise in a gear system is the transmission error between the meshing gears. Transmission error is caused by manufacturing inaccuracy, mounting errors, and elastic deflections under load. Gear designers often attempt to compensate for transmission error by modifying gear teeth. This is done traditionally by a rough "rule of thumb" or more recently under the guidance of an analytical code. In order for a designer to have confidence in a code, the code must be validated through experiment. NASA Glenn Research Center contracted with the Design Unit of the University of Newcastle in England for a system to measure the transmission error of spur and helical test gears in the NASA Gear Noise Rig. The new system measures transmission error optically by means of light beams directed by lenses and prisms through gratings mounted on the gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. A photodetector circuit converts the light to an analog electrical signal. To increase accuracy and reduce "noise" due to transverse vibration, there are parallel light paths at the top and bottom of the gears. The two signals are subtracted via differential amplifiers in the electronics package. The output of the system is 40 mV/mm, giving a resolution in the time domain of better than 0.1 mm, and discrimination in the frequency domain of better than 0.01 mm. The new system will be used to validate gear analytical codes and to investigate mechanisms that produce vibration and noise in parallel axis gears.

  14. CNC FLEXIBLE GENERATING SPECIFIC GEAR TOOTH PROFILE BASED ON STANDARD INVOLUTE GEAR HOB

    Institute of Scientific and Technical Information of China (English)

    Feng Xianying; Li Hui; Ai Xing

    2004-01-01

    A new method named orthogonal two-way link-shift here has been proposed. Based on the method and a standard involute gear hob, a specific gear tooth profile (including an arbitrary gear tooth profile and a modified involute gear tooth profile) can be generated on a CNC(computer numerical control) hobbing machine. Computer simulation has been carried out, and the results prove that the method is right and practicable. So, the fabrication costs can be greatly decreased than before. The new method has momentous significance to realize gear's optimized modification under different work conditions.

  15. Financing Professional Sports Facilities

    OpenAIRE

    Baade, Robert A.; Victor A. Matheson

    2011-01-01

    This paper examines public financing of professional sports facilities with a focus on both early and recent developments in taxpayer subsidization of spectator sports. The paper explores both the magnitude and the sources of public funding for professional sports facilities.

  16. Consumers' perceptions and opinions of sports injuries: an exploratory empirical study.

    Science.gov (United States)

    Chandra, Ashish; Dunn, David; Paul, David P

    2008-01-01

    Millions of individuals in the United States play some sports or are involved in strenuous physical activities on a regular basis. Unfortunately, many suffer injuries due to these activities. The authors devised this study to determine consumers' perceptions and opinions associated with the injuries that they or someone they know sustained. The results of this study are beneficial to health professionals involved in preventive and rehabilitative medicine as well as sports-related protective-gear marketers.

  17. Research of the Pressure Angle for Whole Cycloidal Gears

    Institute of Scientific and Technical Information of China (English)

    LIU Ling-tao; WANG Jian-hua

    2011-01-01

    The working profile of whole cycloidal gear is made up of epicycloid and hypocycloid entirely, according to the theory of meshing of gears and the properties of the cycloid, deals with the derivation of the pressure angle formula for the whole cycloidal gear in theory, and reveals changes of the pressure angle of whole cycloidal gear through examples, finds the application relationships between the pressure angle and other design parameters of the whole cycloidal gear, proves the possibility that the whole cycloidal gear can be used in internal parallel move gear mechanism, also provides theoretic fundament for designing internal parallel move whole cycloidal gear correctly.

  18. Systematic Reviews in Sports Medicine.

    Science.gov (United States)

    DiSilvestro, Kevin J; Tjoumakaris, Fotios P; Maltenfort, Mitchell G; Spindler, Kurt P; Freedman, Kevin B

    2016-02-01

    The number of systematic reviews published in the orthopaedic literature has increased, and these reviews can help guide clinical decision making. However, the quality of these reviews can affect the reader's ability to use the data to arrive at accurate conclusions and make clinical decisions. To evaluate the methodological and reporting quality of systematic reviews and meta-analyses in the sports medicine literature to determine whether such reviews should be used to guide treatment decisions. The hypothesis was that many systematic reviews in the orthopaedic sports medicine literature may not follow the appropriate reporting guidelines or methodological criteria recommended for systematic reviews. Systematic review. All clinical sports medicine systematic reviews and meta-analyses from 2009 to 2013 published in The American Journal of Sports Medicine (AJSM), The Journal of Bone and Joint Surgery (JBJS), Arthroscopy, Sports Health, and Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) were reviewed and evaluated for level of evidence according to the guidelines from the Oxford Centre for Evidence-Based Medicine, for reporting quality according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and for methodological quality according to the Assessment of Multiple Systematic Reviews (AMSTAR) tool. Analysis was performed by year and journal of publication, and the levels of evidence included in the systematic reviews were also analyzed. A total of 200 systematic reviews and meta-analyses were identified over the study period. Of these, 53% included evidence levels 4 and 5 in their analyses, with just 32% including evidence levels 1 and 2 only. There were significant differences in the proportion of articles with high levels of evidence (P Sports Health and KSSTA on the PRISMA and AMSTAR. The average PRISMA score by year varied from 85% to 89%, and the average AMSTAR score varied from 70% to 76%. Systematic reviews

  19. PRESENT TIMES SPORT MANAGEMENT

    OpenAIRE

    Silvia GRĂDINARU

    2016-01-01

    The goal of this paper is to play as introduction for the sport management science, both as academic and professional major. The paper provides a broad overview of sport management rather than detailed instructions about how sport management is seen. The professional career in sport management should be built on a strong conceptual foundation. Sport managers who can think critically about sport – related issues will be competent, reflective professionals who have the potential to become influ...

  20. Detection and Diagnosis of Gear Fault By the Single Gear Tooth Analysis Technique

    Institute of Scientific and Technical Information of China (English)

    MENG Tao; LIAO Ming-fu

    2003-01-01

    This paper presents a procedure of single gear tooth analysis for early detection and diagnosis of gear faults. The objective of this procedure is to develop a method for more sensitive detection of the incipient faults and locating the faults in the gear. The main idea of the single gear tooth analysis is that the vibration signals collected with a high sampling rate are divided into a number of segments with the same time interval. The number of signal segments is equal to that of the gear teeth. The analysis of individual segments reveals more sensitively the changes of the vibration signals in both time and frequency domain caused by gear faults. In addition, the location of a failed tooth can be indicated in terms of the position of the segment that deviates from the normal segments. An experimental investigation verified the advantages of the single gear tooth analysis.

  1. The transfer function method for gear system dynamics applied to conventional and minimum excitation gearing designs

    Science.gov (United States)

    Mark, W. D.

    1982-01-01

    A transfer function method for predicting the dynamic responses of gear systems with more than one gear mesh is developed and applied to the NASA Lewis four-square gear fatigue test apparatus. Methods for computing bearing-support force spectra and temporal histories of the total force transmitted by a gear mesh, the force transmitted by a single pair of teeth, and the maximum root stress in a single tooth are developed. Dynamic effects arising from other gear meshes in the system are included. A profile modification design method to minimize the vibration excitation arising from a pair of meshing gears is reviewed and extended. Families of tooth loading functions required for such designs are developed and examined for potential excitation of individual tooth vibrations. The profile modification design method is applied to a pair of test gears.

  2. Surface contact fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-06-01

    Full Text Available Surface contact fatigue is the most common cause of gear failure. It results in damage to contacting surfaces which can significantly reduce the load-carrying capacity of components, and may ultimately lead to complete failure of a gear. Three types...

  3. Helical Gears Modified To Decrease Transmission Errors

    Science.gov (United States)

    Handschuh, R. F.; Coy, J. J.; Litvin, F. L.; Zhang, J.

    1993-01-01

    Tooth surfaces of helical gears modified, according to proposed design concept, to make gears more tolerant of misalignments and to improve distribution of contact stresses. Results in smaller transmission errors, with concomitant decreases in vibrations and noise and, possibly, increases in service lives.

  4. Study on corrosive grinding of gears

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Careful grinding or honing is usually required in machining of gears in order to improvethe machining quality of gear surface. Thus several grinding additives were used to formulate syn-thetic grinding lubricants similar to superior running-in lubricants. Experimental results show thatthe tooth surface of the produced oblique gear and steel worm becomes extremely smooth aftergrinding at a certain load for about a half to one hour. Especially, the gear surface finished withspecially formulated grinding lubricant reaches mirror-like smoothness. The quality of the geartooth can be improved by corrosive grinding, while the corrosive grinding time can be controlled byadjusting the quantity of the corrosive additives and the speed and load of the gears.

  5. Vibration signature analysis of multistage gear transmission

    Science.gov (United States)

    Choy, F. K.; Tu, Y. K.; Savage, M.; Townsend, D. P.

    1989-01-01

    An analysis is presented for multistage multimesh gear transmission systems. The analysis predicts the overall system dynamics and the transmissibility to the gear box or the enclosed structure. The modal synthesis approach of the analysis treats the uncoupled lateral/torsional model characteristics of each stage or component independently. The vibration signature analysis evaluates the global dynamics coupling in the system. The method synthesizes the interaction of each modal component or stage with the nonlinear gear mesh dynamics and the modal support geometry characteristics. The analysis simulates transient and steady state vibration events to determine the resulting torque variations, speeds, changes, rotor imbalances, and support gear box motion excitations. A vibration signature analysis examines the overall dynamic characteristics of the system, and the individual model component responses. The gear box vibration analysis also examines the spectral characteristics of the support system.

  6. FATIGUE PROPERTIES OF SPRING REINFORCES POLYMER GEARS

    Directory of Open Access Journals (Sweden)

    Hilal CAN

    2005-03-01

    Full Text Available Failure of gears, occur surface pressure stress and fracture at base of teeth. For steel gears, it is known that process of carburizing increases fatigue strength. Internal stress on the surface increases of fracture fatigue strength. In this study fatigue properties of polypropylene gear reinforced with 1.2 mm wire diameter metallic springs was investigated. Extension springs were used as reinforcement element and placed into the mould and stretched before injection of polypropylene material into the mould. After injection of polypropylene, stretched springs were loosened in order to obtain pre-stressing. Fatigue tests were performed on the produced gear. Reinforcement increased the strength of gears. At result of experiments, pre-stressing increase in service life 12 times more than that of specimens without reinforcement.

  7. The Dilemma of Derelict Gear

    Science.gov (United States)

    Scheld, A. M.; Bilkovic, D. M.; Havens, K. J.

    2016-01-01

    Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million—a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.

  8. The optimal design of involute gear teeth with unequal addenda

    Science.gov (United States)

    Savage, M.; Coy, J. J.; Townsend, D. P.

    1982-01-01

    The design of a gear mesh is treated with the objective of minimizing the gear size for a given gear ratio, pinion torque, pressure angle, and allowable tooth lengths. Tooth strengths considered include scoring, pitting fatigue, and bending fatigue. Kinematic involute interference is avoided. The design variation on standard spur gear teeth called the long and short addendum system, is considered. In this system the mesh center distance and pressure angle are maintained as is the ability to manufacture the teeth with standard tooling. However, the pinion and gear tooth proportions are altered in order to obtain fewer teeth numbers for the same ratio as standard gears without kinematic involute interference. The effect of this nonstandard gearing geometry with on tooth strengths and gear mesh size are studied. For a 2:1 gearing ratio, the optimal nonstandard gear design is compared with the optimal standard gear design.

  9. Dynamics of early planetary gear trains

    Science.gov (United States)

    August, R.; Kasuba, R.; Frater, J. L.; Pintz, A.

    1984-01-01

    A method to analyze the static and dynamic loads in a planetary gear train was developed. A variable-variable mesh stiffness (VVMS) model was used to simulate the external and internal spur gear mesh behavior, and an equivalent conventional gear train concept was adapted for the dynamic studies. The analysis can be applied either involute or noninvolute spur gearing. By utilizing the equivalent gear train concept, the developed method may be extended for use for all types of epicyclic gearing. The method is incorporated into a computer program so that the static and dynamic behavior of individual components can be examined. Items considered in the analysis are: (1) static and dynamic load sharing among the planets; (2) floating or fixed Sun gear; (3) actual tooth geometry, including errors and modifications; (4) positioning errors of the planet gears; (5) torque variations due to noninvolute gear action. A mathematical model comprised of power source, load, and planetary transmission is used to determine the instantaneous loads to which the components are subjected. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. The dynamic model has nine degrees of freedom resulting in a set of simultaneous second order differential equations with time varying coefficients, which are solved numerically. The computer program was used to determine the effect of manufacturing errors, damping and component stiffness, and transmitted load on dynamic behavior. It is indicated that this methodology offers the designer/analyst a comprehensive tool with which planetary drives may be quickly and effectively evaluated.

  10. Writing lives in sport

    DEFF Research Database (Denmark)

    Christensen, Mette Krogh

    Writing lives in sport is a book of stories about sports-persons. The people concerned include sports stars, sports people who are not quite so famous, and relatively unknown physical education teachers and sports scientists.Writing lives in sport raises questions about writing biographies...... in the academis world of sport studies. It does not set out to be a methodological treatise but through the writing of lives in sports does raise questions of method. Each essay in this collection deals with problems of writing sports-people's lives. These essays could be said to fall along a spectrum from those...... of the essays fails to recognise problems of sport-biography. Indeed, several focus explicitly on exemplifications of these problems and as such the book raises important questions for writing in a variety of sporting and educational disciplines....

  11. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten; LS Sportontw. & Managing Social Issues; UU LEG Research USG Public Matters Managing Social Issues; LS Management van Cultuur en Zingeving

    2014-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to ex

  12. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten; LS Sportontw. & Managing Social Issues; UU LEG Research USG Public Matters Managing Social Issues; LS Management van Cultuur en Zingeving

    2014-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to ex

  13. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten

    2015-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to ex

  14. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten

    2015-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to

  15. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten; LS Sportontw. & Managing Social Issues; UU LEG Research USG Public Matters Managing Social Issues; LS Management van Cultuur en Zingeving

    2014-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to

  16. Creating sport consumers in Dutch sport policy

    NARCIS (Netherlands)

    van der Roest, Jan Willem; Vermeulen, Jeroen; van Bottenburg, Maarten

    2015-01-01

    This article deals with the tension between the association logic and the market logic that appears in the domain of voluntary sport clubs (VSCs). We present a qualitative analysis of sport policy texts of fifteen Dutch national sport organizations (NSOs) and the national umbrella organization to ex

  17. Dynamic simulation of planetary gear set with flexible spur ring gear

    Science.gov (United States)

    Chen, Zaigang; Shao, Yimin; Su, Daizhong

    2013-12-01

    Ring gear is a key element for vibration transmission and noise radiation in the planetary gear system which has been widely employed in different areas, such as wind turbine transmissions. Its flexibility has a great influence on the mesh stiffness of internal gear pair and the dynamic response of the planetary gear system, especially for the thin ring cases. In this paper, the flexibility of the internal ring gear is considered based on the uniformly curved Timoshenko beam theory. The ring deformation is coupled into the mesh stiffness model, which enables the investigation on the effects of the ring flexibility on the mesh stiffness and the dynamic responses of the planetary gear. A method about how to synthesize the total mesh stiffness of the internal gear pairs in multi-tooth region together with the ring deformation and the tooth errors is proposed. Numerical results demonstrate that the ring thickness has a great impact on the shape and magnitude of the mesh stiffness of the internal gear pair. It is noted that the dynamic responses of the planetary gear set with equally spaced supports for the ring gear are modulated due to the cyclic variation of the mesh stiffness resulted from the presence of the supports, which adds more complexity in the frequency structure.

  18. Nonlinear Dynamics and Optimization of Spur Gears

    Science.gov (United States)

    Pellicano, Francesco; Bonori, Giorgio; Faggioni, Marcello; Scagliarini, Giorgio

    In the present study a single degree of freedom oscillator with clearance type non-linearity is considered. Such oscillator represents the simplest model able to analyze a single teeth gear pair, neglecting: bearings and shafts stiffness and multi mesh interactions. One of the test cases considered in the present work represents an actual gear pair that is part of a gear box of an agricultural vehicle; such gear pair gave rise to noise problems. The main gear pair characteristics (mesh stiffness and inertia) are evaluated after an accurate geometrical modelling. The meshing stiffness of the gear pair is piecewise linear and time varying (in particular periodic); it is evaluated numerically using nonlinear finite element analysis (with contact mechanics) for different positions along one mesh cycle, then it is expanded in Fourier series. A direct numerical integration approach and a smoothing technique have been considered to obtain the dynamic scenario. Bifurcation diagrams of Poincaré maps are plotted according to some sample case study from literature. Optimization procedures are proposed, in order to find optimal involute modifications that reduce gears vibration.

  19. Enhancement in Sport, and Enhancement outside Sport.

    Science.gov (United States)

    Douglas, Thomas

    2007-12-01

    Sport is one of the first areas in which enhancement has become commonplace. It is also one of the first areas in which the use of enhancement technologies has been heavily regulated. Some have thus seen sport as a testing ground for arguments about whether to permit enhancement. However, I argue that there are fairness-based objections to enhancement in sport that do not apply as strongly in some other areas of human activity. Thus, I claim that there will often be a stronger case for permitting enhancement outside of sport than for permitting enhancement in sport. I end by considering some methodological implications of this conclusion.

  20. Sports Culture and Sports in Turkey

    Directory of Open Access Journals (Sweden)

    Yılmaz KAPLAN

    2014-08-01

    Full Text Available Sports culture indicates all kinds of morals, products, and behavior. This study aims to argue sports as a cultural element and its appearence in Turkey. This is a descriptive study based on theoretical argument. It is periodic since it is limited to a given term and it is also relied upon literature review. People's adaptations to living conditions are related to culture. We can specify this, “all the patt erns of living and behavior which are special to small units within a large and structurally developed society.” ( Erdemli , 2002In Turkey; it’s more accurate to say that, it’s understood football when you think about sports and sport culture is football culture. This condition can not only induce cultural diversity and wealth but it also leads to a transformation into a society who likes watching sports, talking about sports (saying more precisely football rather than doing sports. Sport magazine has sur passed the sport itself. Representation of sport in media does not make a favorable contribution. Sport media invites violence with its manner of representation of news by acting with the concerns of rating and curcilation although they, at every turn, dec lare that they are against violence. Discourses which include violence, nationalism, sexism, and slang has increased in media as an extensive research also suggested ( Talimciler , 2003.Culture, is a phenomenon which is considerably about quality and accumu lation. Processes are as important as results; sometimes even more. In this sense sport is much more than the score. In a country, a sport branch can be attracting more attention than the other ones; however, Limiting sports to football, also limiting fo otball to several football clubs, and ignoring many of sports branches, those who are interested in them, and who are amateurs is an unfair and reductive approach. On the other hand; sports opportunities could not be created for millions of young and adul t people in our country

  1. Microforms and Sport History.

    Science.gov (United States)

    Levine, Peter

    1986-01-01

    Explores the importance of sport history as it reflects the social and cultural history of the United States. Discussion covers the various sport history materials that are available in microform, including the Spalding Collection, twentieth-century microfilm sources, and sports and social history (Sports Periodicals microfilm series). (EJS)

  2. Report on Sport 2008

    NARCIS (Netherlands)

    Koen Breedveld; Carlijn Kamphuis; Annet Tiessen-Raaphorst

    2008-01-01

    Original title: Rapportage sport 2008. Sport: it appeals to people; it brings people together; it promotes health; and it is profitable. Today, in 2008, sport is enjoying popularity as never before. Two-thirds of the Dutch population take part in some form of sport. After swimming and cycling,

  3. Report on Sport 2008

    NARCIS (Netherlands)

    Koen Breedveld; Carlijn Kamphuis; Annet Tiessen-Raaphorst

    2008-01-01

    Original title: Rapportage sport 2008. Sport: it appeals to people; it brings people together; it promotes health; and it is profitable. Today, in 2008, sport is enjoying popularity as never before. Two-thirds of the Dutch population take part in some form of sport. After swimming and cycling, fitn

  4. Sport participation styles revisited

    NARCIS (Netherlands)

    Steven Vos; Erik Thibaut; Bart Vanreusel; Julie Borgers; Hanne Vandermeerschen; Jeroen Scheerder

    2013-01-01

    Social changes have been influencing determinants for sports participation since the introduction of the Sport for All ideology in the early 1970s. Consistent with Crum’s sportisation theory, today’s modes of sports practices, as well as the network of sport services, have diversified and

  5. Building Character through Sports

    Science.gov (United States)

    Lumpkin, Angela

    2011-01-01

    Sports are a focus of millions of Americans as they attend, view, and participate in sports. The World Series, Final Four, and Super Bowl often bring back memories of fun-filled parties and celebrations, but there may be several reasons why sports are so popular in the United States. The popularity of sports, however, does not necessarily mean it…

  6. 46 CFR 108.641 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  7. 29 CFR 1919.31 - Proof tests-loose gear.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  8. 49 CFR 230.77 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  9. 14 CFR 25.1515 - Landing gear speeds.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  10. PRESENT TIMES SPORT MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Silvia GRĂDINARU

    2016-06-01

    Full Text Available The goal of this paper is to play as introduction for the sport management science, both as academic and professional major. The paper provides a broad overview of sport management rather than detailed instructions about how sport management is seen. The professional career in sport management should be built on a strong conceptual foundation. Sport managers who can think critically about sport – related issues will be competent, reflective professionals who have the potential to become influential agents of change. The sport management will face many challenges in the future, as examination of the ethics, social responsibility and principled decision making but in the meantime will offer opportunities towards society.

  11. Sport and measurement of competition

    NARCIS (Netherlands)

    Koning, R.H.

    2009-01-01

    Sport is becoming an activity of increasing importance: over time more people participate in sport (active sport consumption), more time is spent watching sport (passive sport consumption). An important part of sport consumption is passive sport consumption where production and consumption are separ

  12. Engagement of Metal Debris into Gear Mesh

    Science.gov (United States)

    handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  13. Roller/Gear Drives For Robotic Manipulators

    Science.gov (United States)

    Anderson, William J.; Shipitalo, William

    1995-01-01

    Pitch/yaw roller/gear drive and wrist-roll roller/gear drive designed to incorporate several features desirable in robotic-joint actuators. Includes zero backlash, high efficiency, smooth motion (little ripple in torque and in speed ratio), and high degree of back-drivability. Pitch/yaw drive is novel two-axis drive containing combination of gears, rollers, and springs acting together eliminating backlash and cogging. Wrist-roll drive more-conventional single-axis drive offering advantages like those of pitch/yaw drive.

  14. Automatic gear sorting system based on monocular vision

    Directory of Open Access Journals (Sweden)

    Wenqi Wu

    2015-11-01

    Full Text Available An automatic gear sorting system based on monocular vision is proposed in this paper. A CCD camera fixed on the top of the sorting system is used to obtain the images of the gears on the conveyor belt. The gears׳ features including number of holes, number of teeth and color are extracted, which is used to categorize the gears. Photoelectric sensors are used to locate the gears׳ position and produce the trigger signals for pneumatic cylinders. The automatic gear sorting is achieved by using pneumatic actuators to push different gears into their corresponding storage boxes. The experimental results verify the validity and reliability of the proposed method and system.

  15. Efficiency of nonstandard and high contact ratio involute spur gears

    Science.gov (United States)

    Anderson, N. E.; Loewenthal, S. H.

    1986-01-01

    A power loss prediction was extended to include involute spur gears of nonstandard proportions. The method is used to analyze the effects of modified addendum, tooth thickness, and gear center distance in addition to the parameters previously considered which included gear diameter, pitch, pressure angle, face width, oil viscosity, speed, and torque. Particular emphasis was placed on high contact ratio gearing (contact ratios greater than two). Despite their higher sliding velocities, high contact ratio gears are designed to levels of efficiency comparable to those of conventional gears while retaining their advantages through proper selection of gear geometry.

  16. DESIGN FOR A BI-PLANETARY GEAR TRAIN

    Directory of Open Access Journals (Sweden)

    Józef DREWNIAK

    2016-06-01

    Full Text Available The article presents the design for a bi-planetary gear train. The project description is supplemented with calculations of kinematics, statics and meshing efficiency of the gear wheels included in the gear train. Excluded are calculations of strength and geometry of gears, shaft and rolling bearing, since they are similar to classical calculations for planetary gears. An assembly drawing in 2D and assembly drawings in 3D of the designed bi-planetary gear train are also shown. This gear train will form the main element of the research in hand.

  17. Performance improvement of magnetic gear and efficiency comparison with conventional mechanical gear

    Science.gov (United States)

    Nakamura, Kenji; Fukuoka, Michinari; Ichinokura, Osamu

    2014-05-01

    Magnetic gears can transmit torque without any mechanical contact. Hence, they have low vibration, no wear, and fatigue, which ensure maintenance-free operation. There are various types of magnetic gears. Among them, a planetary type magnetic gear, which consists of coaxial inner and outer rotors with surface-mounted permanent magnet and ferromagnetic stationary parts called pole-pieces, has recently attracted interest since it offers higher torque than other type magnetic gears. This paper presents a comprehensive investigation of the influence of geometry and position of the pole-pieces on torque characteristic based on finite element analysis and experiment. Surveyed parameters of the pole-pieces include lengths in the radial and axial directions and position in the radial direction. Finally, it is demonstrated that the maximum torque of the improved prototype magnetic gear is increased by 45% and the maximum efficiency achieves up to about 99%, which is equal to or more than a conventional planetary type mechanical gear.

  18. Modeling of the process of gear shifting in planetary gear trains of motor vehicles

    Directory of Open Access Journals (Sweden)

    Aleksandar R. Grkić

    2011-04-01

    Full Text Available Gear boxes, i. e. the realization of their functions, especially gear shift, have a big impact on vehicle operation quality through their effects on the performance of vehicles and their comfort. This paper shows a method of modeling the transition process during gear shifting in planetary gear trains. The simulation model is developed with in order to provide virtual research of planetary gear trains, which would positively decrease the number of real prototypes, thus considerably saving time and contributing to the quality improvement of the final product (planetary gear train and vehicles in general. Introduction Modeling of gear shift processes has been carried out on the planetary gear type Ravigneaux used in planetary gear trains of motor vehicles. The model was developed modularly, so that more simulation models can be added to the whole. At the same time each subsystem is a model for itself and can be used independently from the main model. Simplified engine model Bearing in mind that, for the simulation of the planetary gear which is the subject of this paper, the necessary input parameters are in the form of engine torque Mm, angular velocity and motor ωm moment of inertia of rotating engine components reduced to the input shaft gear, a simplified model of an internal combustion engine has been formed. Model of external load External load resistance is in the form of the torque Mt occurring on the drive wheel of the vehicle. On the other hand, this load is defined by the moment of inertia of rotating elements from the planetary gear to the drive wheel, reduced to the output shaft. Model of friction transmission simulation Transmission power control in planetary gears is achieved through friction components. The output size of this subsystem is the moment of carrying the friction assembly. Simulation model of the planetary gear train The model simulation of the planetary gear type Ravigneaux was formed in accordance with the kinematic

  19. Estimation of gear tooth transverse crack size from vibration by fusing selected gear condition indices

    Science.gov (United States)

    Choi, Sukhwan; Li, C. James

    2006-09-01

    Gears are common power transmission elements and are frequently responsible for transmission failures. Since a tooth crack is not directly measurable while a gear is in operation, one has to develop an indirect method to estimate its size from some measurables. This study developed such a method to estimate the size of a tooth transverse crack for a spur gear in operation. Using gear vibrations measured from an actual gear accelerated test, this study examined existing gear condition indices to identify those correlated well to crack size and established their utility for crack size estimation through index fusion using a neural network. When tested with vibrations measured from another accelerated test, the method had an averaged estimation error of about 5%.

  20. High Speed Gear Sized and Configured to Reduce Windage Loss

    Science.gov (United States)

    Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

    2013-01-01

    A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

  1. Bending Fatigue Strength of Austempered Ductile Iron Spur Gears

    Science.gov (United States)

    Yamanaka, Masashi; Tamura, Ryo; Inoue, Katsumi; Narita, Yukihito

    This paper deals with an experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears. The module is 2.5 and the number of teeth is 26 in the test gears. The material of the test gears corresponds to Japan Industrial Standard (JIS) FCAD1100-15. Some gears are processed by one of two types of fine particle bombarding (FPB). The surface roughness is slightly increased by FPB. The obtained strengths are 623 MPa for the as-austempered gears, and 1011 and 1085 MPa for the gears after FPB. The strength is expressed by the fillet stress level, which is calculated by FEM. The strength of a gear with the same dimensions made of carburized SCr420H alloy steel is 1205 MPa, and the strength of the ADI gear is approximately half that of the carburized steel gear. The FPB process has a significant effect on the ADI gear, improving its strength by 62-74%.

  2. Short convalescence after vaginal prolapse surgery

    DEFF Research Database (Denmark)

    Ottesen, Marianne; Sørensen, Mette; Kehlet, Henrik

    2003-01-01

    , 0-24) after first-time prolapse surgery. In the prospective study, there were 41 consecutive women with a median age of 69 years (range, 44-88). Convalescence was median intercourse, sports and work with lifts...

  3. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Thigh Knee & Lower Leg Foot & Ankle Neck & Back Health Centers Broken Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries Joint Replacement Rehabilitation ...

  4. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Thigh Knee & Lower Leg Foot & Ankle Neck & Back Health Centers Broken Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries Joint Replacement Rehabilitation ...

  5. Preventing Blood Clots After Orthopaedic Surgery

    Medline Plus

    Full Text Available ... Bones & Injuries Diseases & Conditions Arthritis Tumors Sports Injuries & Prevention Children Bone Health Health & Safety Treatment Treatments & Surgeries ... video provides additional information about DVT and its prevention. This video © American Academy of Orthopaedic Surgeons. Many ...

  6. Prediction of potential failures in hydraulic gear pumps

    OpenAIRE

    E. Lisowski(Cracow Tech. U); J. Fabiś

    2010-01-01

    Hydraulic gear pumps are used in many machines and devices. In hydraulic systems of machines gear pumps are main component ofsupply unit or perform auxiliary function. Gear pumps opposite to vane pumps are less complicated. They consists of such components as:housing, gear wheels, bearings, shaft, seal for rotation motion which are not very sensitive for damage and that is why they are using veryoften. However, gear pumps are break down from time to time. Usually damage of pump cause shutting...

  7. Gear servicing in the wind power industry; Getriebeservice Windenergie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    JaKe (Jahnel-Kestermann) is a producer of gears for wind power systems. They offer: Damage analysis anddocumentation; supply of replacement parts; repair and modification of gears; world-wide gear servicing; new gears for own and external products; mobile measuring systems; technological improvements; production of components; toothing, grinding, meshing measurements; production of exchange gears; test performance up to 3 MW; short supply times. (orig.)

  8. Surface micromachined microengine as the driver for micromechanical gears

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, E.J.; Sniegowski, J.J.

    1995-05-01

    The transmission of mechanical power is often accomplished through the use of gearing. The recently developed surface micromachined microengine provides us with an actuator which is suitable for driving surface micromachined geared systems. In this paper we will present aspects of the microengine as they relate to the driving of geared mechanisms, issues relating to the design of micro gear mechanisms, and details of a design of a microengine-driven geared shutter mechanism.

  9. Deformation and stiffness of spur gear teeth and their influence on gear noise

    Directory of Open Access Journals (Sweden)

    Silvia MEDVECKÁ-BEŇOVÁ

    2015-12-01

    Full Text Available Gear teeth are deformed due to the load. The deformation of gear teeth is causing some negative as well as positive effects. A tooth has a complex shape and due to the complex shape of the teeth, a theoretical determination of the deformation is difficult. The existing experimental techniques are based on static deflection measurements gearing loaded of constant force or seismic measurement deviations at slow rotation. Recently, at ever faster evolving computer technology and the available literature, we can encounter modern numerical methods, such as finite element method (FEM, which can serve as methods for the determination of teeth of gearing. The article is devoted to the problems of gearing stiffness analysis. The problem is solved for spur gears. Deformation analysis solved by FEM is used for calculations of the gearing stiffness. There are many influences that cause vibrations in the gearbox and that have to be taken into account already in the phase of design, manufacture, installation and operation. Detailed analysis of gearboxes manufacturers have shown that improving of the gear accuracy cannot reduce the transmission unit noise to the desired level. Only fundamental changes to the shape of the tooth and changes in production technology can achieve stronger noise reduction of gear mechanism.

  10. Gulf of Mexico Shrimp Permit Gear Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data set contains annual vessel gear characterization of permit holders shrimp vessel. Data includes net type, TED type, BRD type, etc.

  11. Sea Turtle Human/Gear Interactions Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories is responsible for new gear development and testing to reduce bycatch and incidental interactions of...

  12. 50 CFR 300.109 - Gear disposal.

    Science.gov (United States)

    2010-10-01

    ... articles and substances include, but are not limited to, fishing gear, net scraps, bale straps, plastic... waters. (c) The operator of a harvesting vessel must provide a copy of the CCAMLR information...

  13. Modelling of vibration of gear transmissions

    Science.gov (United States)

    Zeman, Vladimir; Nemecek, Josef

    The method for mathematical modeling of spatial vibrations of the spur gear transmissions is presented. This method enables a substantial reduction of the number of degrees of freedom with relatively high accuracy in calculating vibration amplitude.

  14. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  15. Gear noise behavior induced by their topological quality

    Science.gov (United States)

    Jolivet, S.; Mezghani, S.; El Mansori, M.; Zahouani, H.

    2014-01-01

    The upcoming fuel economy standards will result in the rapid development of electric or hybrid vehicles. Such regulatory demands will affect transmission design, which is currently driving changes in the number, type, size and quality levels of gears. Thus, gear manufacturers need to create high quality gear flanks with special topological modifications. The most important objectives are to increase the load-carrying capacity of gears and also to reduce the gear noise behavior. The teeth surface is at the heart of gear meshing mechanics and is one of the main elements in the generation of noise. The most common gear wear mechanisms are micro-pitting, pitting and spalling, which often occur on teeth surface during the early stage of failure. This study aims to identify the scale effect of pitting defects of gear teeth surface on the acoustics response of a spur gear pair. Consequently, we have developed a two-dimensional finite-element simulation model of a one-stage gear system. The transmission system was composed of two identical spur gears with one degree of freedom. Pitting defects versus topological features at different scales were modeled on the gear tooth flanks. To quantify their impact on gear noises and vibrations, we used contact stiffness as our criteria because it is directly linked to gear noise. The prevalence of the gear quality and its topological features on power density and sound issues are computed and discussed in this paper.

  16. Instrumentation and test gear circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Instrumentation and Test Gear Circuits Manual provides diagrams, graphs, tables, and discussions of several types of practical circuits. The practical circuits covered in this book include attenuators, bridges, scope trace doublers, timebases, and digital frequency meters. Chapter 1 discusses the basic instrumentation and test gear principles. Chapter 2 deals with the design of passive attenuators, and Chapter 3 with passive and active filter circuits. The subsequent chapters tackle 'bridge' circuits, analogue and digital metering techniques and circuitry, signal and waveform generation, and p

  17. The processing accuracy of the gear

    Directory of Open Access Journals (Sweden)

    Mazuru Sergiu

    2017-01-01

    Full Text Available The paper presents analysis of processing quality of gears. A special attention was drawn to detecting and removing burns, the existence of which greatly reduced operating properties of gears. The study emphases the influence of schemes, processing modes and abrasive tools features on the physico-mechanical layer of teeth processed and phase changes, micro-cracks appearances, depth and degree of hardening, meaning and character of residual stresses distribution.

  18. Ultrasonic test of highly stressed gear shafts

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, T. [Siemens AG, Power Generation, KWU, Muelheim (Germany); Heinrich, W. [Siemens AG, Power Generation, KWU, Berlin (Germany); Achtzehn, J. [Siemens AG, Power Generation, ICVW, Erlangen (Germany); Hensley, H. [Siemens Power Generation (Germany)

    1998-12-31

    In the power plant industry, gears are used for increasingly higher turbine capacities. Efficiency enhancements, particularly for the combined gas and steam turbine process, lead to an increase in stresses, even for high-performance gears. Consequently, the requirements for non-destructive material testing are on the increase as well. At Siemens KWU, high-performance gears are used so far only for gas turbines with lower rating (65 MW) to adapt the gas turbine speed (5413 rpm) to the generator speed (3000 rpm/ 50 Hz or 3600 rpm/60 Hz). The gear train consists of a forged and case-hardened wheel shaft and pinion shaft made of material 17 CrNiMo 6, where the wheel shaft can be either a solid or a hollow shaft. Dimensions are typically 2.3 m length and 1 m diameter. As a rule, pinion shafts are solid. The gear design, calling for an additional torsion shaft turning inside the hollow wheel shaft, can absorb more torsional load surges and is more tolerant of deviations during gear train alignment. This design requires two additional forgings (torsion shaft and hub) and an additional bearing 2 refs.

  19. Bearing and gear steels for aerospace applications

    Science.gov (United States)

    Zaretsky, Erwin V.

    1990-01-01

    Research in metallurgy and processing for bearing and gear steels has resulted in improvements in rolling-element bearing and gear life for aerospace application by a factor of approximately 200 over that obtained in the early 1940's. The selection and specification of a bearing or gear steel is dependent on the integration of multiple metallurgical and physical variables. For most aerospace bearings, through-hardened VIM-VAR AISI M-50 steel is the material of preference. For gears, the preferential material is case-carburized VAR AISI 9310. However, the VAR processing for this material is being replaced by VIM-VAR processing. Since case-carburized VIM-VAR M-50NiL incorporates the desirable qualities of both the AISI M-50 and AISI 9310 materials, optimal life and reliability can be achieved in both bearings and gears with a single steel. Hence, this material offers the promise of a common steel for both bearings and gears for future aerospace applications.

  20. Lightly loaded lubricated impacts: Idle gear rattle

    Science.gov (United States)

    Tangasawi, O.; Theodossiades, S.; Rahnejat, H.

    2007-12-01

    Idle gear rattle is associated with the characteristic noise that unselected impacting gears radiate to the environment. It is induced by engine order vibration in the presence of backlash in the unengaged gear pairs, resulting in oscillatory response within their backlash range. A tribo-dynamic model of a front wheel drive manual transmission has been developed to study idle rattle, considering the hydrodynamic contact film reaction and flank friction. The model includes the torsional motions of the idle gears and the lateral motions of the supporting output shafts. The hydrodynamic lubricant film formed between the gear teeth under light impact loads behaves as a nonlinear spring-damper mechanism, whilst the inclusion of the shafts' bearing compliances introduces additional nonlinear terms, which are modelled as piecewise linear functions. The aim of the paper is to extend the existing methodology reported by the authors on idle rattle investigations of geared lubricated systems, based on torsional vibrations only, by considering the system response, which is eventually transferred to the gearbox case through the bearings. These are preliminary results found, which conform closely to experimental measurements taken from a vehicle equipped with a manual transmission of the same type.

  1. Writing lives in sport

    DEFF Research Database (Denmark)

    Christensen, Mette Krogh

    Writing lives in sport is a book of stories about sports-persons. The people concerned include sports stars, sports people who are not quite so famous, and relatively unknown physical education teachers and sports scientists.Writing lives in sport raises questions about writing biographies...... in the academis world of sport studies. It does not set out to be a methodological treatise but through the writing of lives in sports does raise questions of method. Each essay in this collection deals with problems of writing sports-people's lives. These essays could be said to fall along a spectrum from those...... dealing with anonymous individuals, whose anonymity results from the confidentiality requirements of a social scientific research methodology, to those leaning more towards the literary-historical traditions of 'conventional' biographical writing. However, these examples are polar extremes and none...

  2. Design rules to enhance HUMS sensitivity to spur gear faults

    Science.gov (United States)

    Liu, Lin

    This dissertation describes the investigation of spur gear design rules that may enhance the sensitivity of conventional fault metrics to typical gear tooth damage. Spur gears represent a fundamental gear geometry that is commonly used in complex transmission system. This thesis explores the influence of simple spur gear design parameters such as diametral pitch, tooth number and pressure angle on gear tooth fault sensitivity. Using static and dynamic analysis, coupled with vibration based fault metrics (FM0, FM4, DI), this work attempts to determine the influence of RPM level, and gear geometry on vibration signatures. Specifically, three types of gear damage are modeled. These include pitting, crack and wear damage. Using a Cornell's gear tooth deflection method, a quasi-static nonlinear mesh gear model is developed that includes effects associated with gear tooth damage. This quasi-static model is integrated into a rigid body model of spur gear mesh dynamics under an applied load. This model is used to simulate the gear mesh dynamics under various RPM levels and applied torque loads. Additionally, the filtering effect of bearing is investigated based on a bearing model. Simulated vibration signatures of bearing case with and without gear tooth damage are used as input into conventional vibration based fault metrics. Assuming that for each spur gear design the gear tooth critical tensile or contact stress is held constant, this dynamic model enables one to vary gear design parameters to evaluate their effect on the vibration signature with and without damage. In this dissertation, the sensitivity of gear design parameters to gear tooth damage is investigated under quasi-static and dynamic loading conditions. Experimental validation is carried out for spur gear designs with various diametral pitch values and for spur gears with increasing crack damage. In the static analysis, enhanced sensitivity is measured with respect to the transmission error. In the dynamic

  3. [Sports medicine in Germany].

    Science.gov (United States)

    Dickhuth, H-H

    2005-08-01

    Sports medicine covers many different aspects, ranging from clinical specialties, such as internal medicine, orthopedics or pediatrics to physiology and sports sciences. The requirements for sports medicine evolve mainly from exercise physiology (elite, leisure and health oriented physical activity), orthopedics and traumatology as well as from preventive and rehabilitative issues. In the new German curriculum, sports medicine is defined as a subspecialty. Historically, sports medicine in Germany has a federal structure with a governing body (Deutsche Gesellschaft für Sportmedizin und Prävention). Due to these facts, University Departments of Sports Medicine (which vary greatly in size and performance) are either attached to Medical or non-Medical Faculties, such as Sports Sciences. In medical schools, sports medicine can be selected as an elective subject. However, the main part of teaching sports medicine is covered by Sports Science Faculties. In an international context, the strength of German sports medicine is its clinical orientation and close cooperation with the sport itself, especially high-performance sports. In the future, like in the Anglo- American countries, sports medicine in Germany will play a major role in health prevention and rehabilitation.

  4. Gear Tooth Root Stresses of a Very Heavily Loaded Gear Pair-Case Study: Orbiter Body Flap Actuator Pinion and Ring Gear

    Science.gov (United States)

    Krantz, Timothy L.; Handschuh, Robert F.

    2015-01-01

    The space shuttle orbiter's body flap actuator gearing was assessed as a case study of the stresses for very heavily loaded external-internal gear pairs (meshing pinion and ring gear). For many applications, using the high point of single tooth contact (HPSTC) to locate the position of the tooth force is adequate for assessing the maximum tooth root stress condition. But for aerospace gearing such an approach may be inadequate for assessing the stress condition while also simultaneously minimizing mass. In this work specialized contact analyses and finite element methods were used to study gear tooth stresses of body flap actuator gears. The analytical solutions considered the elastic deformations as an inherent part of the solutions. The ratio for the maximum tooth stresses using the HPSTC approach solutions relative to the contact analysis and finite element solutions were 1.40 for the ring gear and 1.28 for the pinion gear.

  5. Nutritional requirements after bariatric surgery.

    Science.gov (United States)

    Bosnic, Gordana

    2014-06-01

    This article presents an overview of postoperative nutritional requirements and goals following bariatric surgery. It summarizes current diet progression and nutrient intake guidelines geared toward optimizing weight loss and maintaining adequate nutritional status, nutrient absorption, as well as hydration. The article further emphasizes the importance of postoperative follow-up with a bariatric multidisciplinary team for appropriate postoperative care, diet management, and nutrient deficiency screenings. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Major international sport profiles.

    Science.gov (United States)

    Patel, Dilip R; Stier, Bernhard; Luckstead, Eugene F

    2002-08-01

    Sports are part of the sociocultural fabric of all countries. Although different sports have their origins in different countries, many sports are now played worldwide. International sporting events bring athletes of many cultures together and provide the opportunity not only for athletic competition but also for sociocultural exchange and understanding among people. This article reviews five major sports with international appeal and participation: cricket, martial arts, field hockey, soccer, and tennis. For each sport, the major aspects of physiological and biomechanical demands, injuries, and prevention strategies are reviewed.

  7. Globalization of the sports economy

    OpenAIRE

    Wladimir Andreff

    2008-01-01

    Introduction – 1. Major features of a globalized sports economy – 2. International economic flows in a global sports economy – 3. Globalization as geographical spread of the sports economy – 4. Globalization of professional sports – Conclusion – References

  8. Laser Heat Treatment on Gear Surface and Its Practical Application

    Institute of Scientific and Technical Information of China (English)

    MA Chun-yin; DAI Zhong-sen; SU Bao-rong

    2004-01-01

    Making gears with hardened tooth flank is one of the important developments in gear manufacturing. However, the conventional heat treating methods have a common shortcoming--producing big deformation. In this work, we demonstrate, by study, experiment and practical use, that not only has the laser heat treatment solved the difficult problems in conventional technique, but also it has great superiority. The use cases proved that the laser-treated gears are able to substitute for all the gears including gears with complicated shape, high precision and high performance imported gears and all those gears that cannot be manufactured by conventional methods. Moreover, our laser-treated gears have won quite good economic benefit.Obviously, the laser heat treatment for gears is a highly competitive technique having good prospects.

  9. Application of face-gear drives in helicopter transmissions

    Science.gov (United States)

    Litvin, F. L.; Wang, J.-C.; Bossler, R. B., Jr.; Chen, Y.-J. D.; Heath, G.; Lewicki, D. G.

    1992-05-01

    The use of face gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face gears was described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. Analytical study of transmission error showed face-gear drives were relatively insensitive to gear misalignment, but tooth contact was affected by misalignment. A method of localizing bearing contact to compensate for misalignment was explored. The proper choice of shaft support stiffness enabled good load sharing in the split torque transmission design. Face-gear experimental studies were also included and the feasibility of face gears in high-speed, high-load applications such as helicopter transmissions was demonstrated.

  10. Handbook on Face Gear Drives with a Spur Involute Pinion

    Science.gov (United States)

    Litvin, F. L.; Egelja, A.; Tan, J.; Chen, D. Y.-D.; Heath, G.

    2000-01-01

    The use of face gears in power transmission and drive systems has a significant number of benefits. Face gears allow a variety of new transmission arrangements as well as high reduction ratio capability. This leads to drive system weight reduction and improvements in performance. In this work, basic information about the design and analysis of face gear drives is presented. The work considers face gears in mesh with spur involute pinions for both intersecting axes and offset drives. Tooth geometry, kinematics, generation of face gears with localized bearing contact by cutting and grinding, avoidance of tooth undercutting, avoidance of tooth pointing, tooth contact analysis, and algorithms for the simulation of meshing and contact arc all topics which are discussed. In addition, applications of face gear drives are presented. Included are design uses in aerospace applications such as helicopter transmissions, split-torque face gear arrangements, comparisons of face gears with bevel gears, and general design considerations.

  11. Application of Face-Gear Drives in Helicopter Transmissions

    Science.gov (United States)

    Litvin, F. L.; Wang, J.-C.; Bossler, R. B., Jr.; Chen, Y.-J. D.; Heath, G.; Lewicki, D. G.

    1992-01-01

    The use of face gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face gears was described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. Analytical study of transmission error showed face-gear drives were relatively insensitive to gear misalignment, but tooth contact was affected by misalignment. A method of localizing bearing contact to compensate for misalignment was explored. The proper choice of shaft support stiffness enabled good load sharing in the split torque transmission design. Face-gear experimental studies were also included and the feasibility of face gears in high-speed, high-load applications such as helicopter transmissions was demonstrated.

  12. Analysis of the Dynamic Characteristics of Elliptical Gears

    Science.gov (United States)

    Liu, Xing; Nagamura, Kazuteru; Ikejo, Kiyotaka

    To date, elliptical gear has been commonly used in automobile, automatic machinery, pumps, flow meters and printing presses for its particular non-uniform rotation. However, the dynamic characteristics of elliptical gears have not been clarified yet. In this study, The calculation as well as the experiment of two elliptical gears, which are a single elliptical gear and a double elliptical gear, is carried out to analyze the dynamic characteristics of elliptical gears. General factors including the torque, the rotation speed and the tooth root stress of the test gears are investigated. According to the analysis conducted in this study, the dynamic input torque variation of elliptical gear becomes larger along with the increase of operating gear rotation speed and the experimental one increases much faster than the calculated one over the Critical Rotation Speed of Tooth Separation (CRSTS) of elliptical gear. The experimental input rotation speed varies according to the variation of input torque, leading to the difference between the experimental output rotation speed and the desired one. The calculation results of the CRSTS of elliptical gears are almost equal to the experimental ones. The dynamic load variation ratios of elliptical gear at different angular position as well as their changing trends with operating gear rotation speed are quite different from each other. And the experimental dynamic load variation ratios of elliptical gear show difference from the calculated ones because of tooth separation and tooth impact. The agreement of the calculation and experimental results proves the validity of this study.

  13. Research on the Problem of Spur Gear Teeth Contact in the Car Gear Box

    Directory of Open Access Journals (Sweden)

    Viktor Skrickij

    2011-04-01

    Full Text Available The article presents research on the problem of two gear contact in the car gearbox. Contact stiffness is evaluated for the whole period of mesh. Also, contact stresses are evaluated in the contact place. The presented method can be used for calculating spur gear.Article in Lithuanian

  14. Achilles tendon lesions in sport.

    Science.gov (United States)

    Williams, J G

    1993-09-01

    Achillodynia (Achilles tendon pain) is a significant source of disability to many people taking part in sports. Papers in the English language published since 1986 are reviewed here, grouped into specific subject areas including biomechanics, pathology, general clinical presentations, experimental treatments, steroids, podiatry and surgery. While there has been no dramatic breakthrough in the field, there have been various interesting advances with particular reference to imaging and conservative management, which will hopefully stimulate further studies. Many problems of Achilles tendon lesions in athletes remain unsolved, however, and much is yet to be done to provide adequate and generally effective methods of prevention and conservative treatment.

  15. Gear and Transmission Research at NASA Lewis Research Center

    Science.gov (United States)

    Townsend, Dennis P.

    1997-01-01

    This paper is a review of some of the research work of the NASA Lewis Research Center Mechanical Components Branch. It includes a brief review of the NASA Lewis Research Center and the Mechanical Components Branch. The research topics discussed are crack propagation of gear teeth, gear noise of spiral bevel and other gears, design optimization methods, methods we have investigated for transmission diagnostics, the analytical and experimental study of gear thermal conditions, the analytical and experimental study of split torque systems, the evaluation of several new advanced gear steels and transmission lubricants and the evaluation of various aircraft transmissions. The area of research needs for gearing and transmissions is also discussed.

  16. What Are Sports Injuries?

    Science.gov (United States)

    ... 06:02 Size: 11.7 MB November 2014 What Are Sports Injuries? Fast Facts: An Easy-to- ... Research Is Being Done on Treating Sports Injuries? What’s the Difference Between an Acute and a Chronic ...

  17. Sports and Concussions

    Science.gov (United States)

    ... Help Someone Who's Being Bullied? Volunteering Sports and Concussions KidsHealth > For Teens > Sports and Concussions Print A ... completely helps prevent long-term problems. How Do Concussions Happen? The brain is soft. The body protects ...

  18. Sports Stars Shine

    Institute of Scientific and Technical Information of China (English)

    Yu Yan

    2012-01-01

    Alive and exciting award ceremony drew the attention of numerous Chinese households on the night of January 15.The most popular Chinese sports stars attended the 2011 CCTV Sports Personality Award Ceremony at the National Indoor Stadium in Beijing.

  19. The Ethics of Sports Medicine Research.

    Science.gov (United States)

    Stewart, Robert J; Reider, Bruce

    2016-04-01

    This article explores the background and foundations of ethics in research. Some important documents and codes are mentioned, such as The Belmont Report and the International Conference of Harmonisation. Some influential historical events involving research ethics are recounted. The article provides a detailed discussion of the Declaration of Helsinki, which is considered the international standard for guidelines in medical research ethics. The most salient features of the Declaration are described and related to orthopaedic surgery and sports medicine. Some of the most controversial aspects of the Declaration are discussed, which helps examine contentious areas of research in sports medicine.

  20. DRUGS IN SPORT

    Directory of Open Access Journals (Sweden)

    David R. Mottram

    2005-12-01

    Full Text Available This new edition includes fresh information regarding drugs use and abuse in sport and the updated worldwide anti-doping laws, and changes to the prohibited and therapeutic use exemption lists. The objectives of the book are to review/discuss the latest information on drugs in sport by considering i actions of drugs and hormones, ii medication and nutritional supplements in sport, iii the latest doping control regulations of the WADA, iv the use of banned therapeutic drugs in sport, v an assessment of the prevalence of drug taking in sport. FEATURES A common, uniform strategy and evidence-based approach to organizing and interpreting the literature is used in all chapters. This textbook is composed of twelve parts with sub-sections in all of them. The topics of the parts are: i An introduction to drugs and their use in sport, ii Drug use and abuse in sport, iii Central nervous system stimulants, iv WADA regulations in relation to drugs used in the treatment of respiratory tract disorders, v Androgenic anabolic steroids, vi Peptide and glycoprotein hormones and sport, vii Blood boosting and sport, viii Drug treatment of inflammation in sports injuries, ix Alcohol, anti-anxiety drugs and sport, x Creatine, xi Doping control and sport, xii Prevalence of drug misuse in sport. Each specific chapter has been systematically developed from the data available in prospective, retrospective, case-control, and cross-sectional studies. The tables and figures are numerous, helpful and very useful. AUDIENCE The book provides a very useful resource for students on sports related courses, coaches and trainers, researchers, nutritionists, exercise physiologists, pharmacologists, healthcare professionals in the fields of sports medicine and those involved in the management and administration side of sport. The readers are going to discover that this is an excellent reference book. Extensively revised new edition of this book is also a first-rate resource for

  1. Drugs in sport

    OpenAIRE

    Mottram, David R

    2007-01-01

    This new edition includes fresh information regarding drugs use and abuse in sport and the updated worldwide anti-doping laws, and changes to the prohibited and therapeutic use exemption lists. The objectives of the book are to review/discuss the latest information on drugs in sport by considering i) actions of drugs and hormones, ii) medication and nutritional supplements in sport, iii) the latest doping control regulations of the WADA, iv) the use of banned therapeutic drugs in sport, v) an...

  2. Relationship between sport commitment and sport consumer behavior

    Directory of Open Access Journals (Sweden)

    Norberta Elisa Fernandes

    2013-12-01

    Full Text Available The purpose of this study was to examine the relationships between sport commitment and three types of sport consumer behaviors: participation frequency, sporting goods and media consumption. A survey was conducted among sport participants of both individual and team sports, fitness and outdoor activities (n= 900. The survey included questions related to demographic information, measures of sport commitment and sport consumption behavior. The results analyzed trough structural equation modeling showed that the sport commitment influences positively the participation frequency, sporting goods consumption and media consumption. Implications of these results are discussed and suggestions for future research on sport consumers are provided.

  3. Bariatric Surgery

    Science.gov (United States)

    ... Metabolic and Bariatric Surgery MedlinePlus What is bariatric surgery? Bariatric surgery helps people who are very obese to ... What are the endocrine-related benefits of bariatric surgery? Bariatric surgery and the weight loss that results can: ...

  4. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    Ibrahim Gunes

    2013-06-01

    In this study, the case properties and diffusion kinetics of GS18NiMoCr36 (GS18), GS22NiMoCr56 (GS22) and GS32NiCrMo6.4 (GS32) gear steels borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2, 4 and 6 h. The boride layer was characterized by optical microscopy, X-ray diffraction technique and microVickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B, CrB and Cr2B compounds. The thickness of the boride layer increases by increasing boriding time and temperature for all steels. The hardness of the boride compounds formed on the surface of the steels GS18, GS22 and GS32 ranged from 1624 to 1905 HV0,05, 1702 to 1948 HV0,05, and 1745 to 2034 HV0,05 respectively, whereas Vickers hardness values of the untreated steels GS18, GS22 and GS32 were 335 HV0,05, 358 HV0,05 and 411 HV0,05, respectively. The activation energies (Q) of borided steels were 228.644 kJ/mol for GS18, 280.609 kJ/mol for GS22 and 294.359 kJ/mol for GS32. The growth kinetics of the boride layers forming on the GS18, GS22 and GS32 steels and the thickness of boride layers were also investigated.

  5. LAW IMPLEMENTATION IN SPORT

    Directory of Open Access Journals (Sweden)

    Mexhid Krasniqi

    2011-09-01

    Full Text Available This work offers a short review of sports marketing and management. It presents different ways of advertising some products either in sports events or throng electronic mediums. In addition, it reviles different aspects of the influence that politics and discrimination has on sport as well as the way of solving eventual arguments of any kind.

  6. Changing spaces for sports

    DEFF Research Database (Denmark)

    Kural, René

    2010-01-01

    The author argues that the fundamental values associated with sports seem to have changed. Accordingly spaces for sports are also undergoing change.The essay gives a number of examples of these new sports spaces. Their common denominator lies in their urban proximity, the combination of previously...

  7. Concussion in Winter Sports

    Science.gov (United States)

    ... Heads Up! Tool Kit Prevent Concussions Prevent Head Injuries Sports Safety Students Play Safe Youth Sports Safety Download ... — United States, 2001–2009 Nonfatal Traumatic Brain Injuries from Sports and Recreation Activities — United States, 2001–2005 ( ...

  8. On Sporting Integrity

    NARCIS (Netherlands)

    Archer, Alfred

    2016-01-01

    It has become increasingly popular for sports fans, pundits, coaches and players to appeal to ideas of ‘sporting integrity’ when voicing their approval or disapproval of some aspect of the sporting world. My goal in this paper will be to examine whether there is any way to understand this idea in a

  9. Report on Sport 2014

    NARCIS (Netherlands)

    Annet Tiessen-Raaphorst

    2015-01-01

    More than half the Dutch population participated in sport on a weekly basis in 2014. Fitness training and running are the most popular sports among adults. Government interventions at the level of neighbourhoods, primary schools, secondary schools and sports clubs are intended to persuade more peopl

  10. 4 Corruption in Sport

    OpenAIRE

    Andreff, Wladimir

    2016-01-01

    International audience; A typology of sport corruption differentiates petty corruption, barter corruption, corruption at the level of sport governing bodies, betting scandals and point-shaving. A deeper analysis goes further as regards match fixing-related bets and global online fraudulent sport betting networks and suggests new tools for combatting match fixing.

  11. Sport Specialization, Part I

    Science.gov (United States)

    Myer, Gregory D.; Jayanthi, Neeru; Difiori, John P.; Faigenbaum, Avery D.; Kiefer, Adam W.; Logerstedt, David; Micheli, Lyle J.

    2015-01-01

    Context: There is increased growth in sports participation across the globe. Sports specialization patterns, which include year-round training, participation on multiple teams of the same sport, and focused participation in a single sport at a young age, are at high levels. The need for this type of early specialized training in young athletes is currently under debate. Evidence Acquisition: Nonsystematic review. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Sports specialization is defined as year-round training (greater than 8 months per year), choosing a single main sport, and/or quitting all other sports to focus on 1 sport. Specialized training in young athletes has risks of injury and burnout, while the degree of specialization is positively correlated with increased serious overuse injury risk. Risk factors for injury in young athletes who specialize in a single sport include year-round single-sport training, participation in more competition, decreased age-appropriate play, and involvement in individual sports that require the early development of technical skills. Adults involved in instruction of youth sports may also put young athletes at risk for injury by encouraging increased intensity in organized practices and competition rather than self-directed unstructured free play. Strength-of-Recommendation Taxonomy (SORT): C. PMID:26502420

  12. Sport in the Netherlands

    NARCIS (Netherlands)

    Annet Tiessen-Raaphorst; Koen Breedveld

    2007-01-01

    Sport is a popular pastime in the Netherlands; 10 million people take part in at least one sport. To do this, they can choose from more than 27,000 non-profit sports clubs, or more than 5,000 commercial providers such as fitness centres or riding stables. These clubs and commercial providers make us

  13. China Sports Museum

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    THE China Sports Museum,inside the National Olympic Sports Center on 3A Anding Road,Andingmenwai, Beijing, is China's First museum dedicated to the nation's sporting history.Its exterior is in the shape of an octagonal spiral, with white

  14. A Computational Investigation of Gear Windage

    Science.gov (United States)

    Hill, Matthew J.; Kunz, Robert F.

    2012-01-01

    A CFD method has been developed for application to gear windage aerodynamics. The goals of this research are to develop and validate numerical and modeling approaches for these systems, to develop physical understanding of the aerodynamics of gear windage loss, including the physics of loss mitigation strategies, and to propose and evaluate new approaches for minimizing loss. Absolute and relative frame CFD simulation, overset gridding, multiphase flow analysis, and sub-layer resolved turbulence modeling were brought to bear in achieving these goals. Several spur gear geometries were studied for which experimental data are available. Various shrouding configurations and free-spinning (no shroud) cases were studied. Comparisons are made with experimental data from the open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility. The results show good agreement with experiment. Interrogation of the validative and exploratory CFD results have led, for the first time, to a detailed understanding of the physical mechanisms of gear windage loss, and have led to newly proposed mitigation strategies whose effectiveness is computationally explored.

  15. RELIABILITY BASED DESIGN OF A GEAR BOX

    Directory of Open Access Journals (Sweden)

    D.MADHUSEKHAR

    2014-08-01

    Full Text Available Reliability is the probability that a system, component or device will perform without failure for a specified period of time under specified operating conditions. The concept of reliability is of great importance in the design of various machine members. Conventional engineering design uses a deterministic approach. It disregards the fact that the material properties, the dimensions of the components and the externally applied loads are statistical in nature. In conventional design this uncertainties are covered with a factor of safety, which is not always successful. The growing trend towards reducing uncertainty and increasing reliability is to use the probabilistic approach. In the present work a three shaft four speed gear box and six speed gear box are designed using reliability principles. For the specified reliability of the system (Gear box, component reliability (Gear pair is calculated by considering the system as a series system. Design is considered to be safe and adequate if the probability of failure of gear box is less than or equal to a specified quantity in each of the two failure modes. . All the parameters affecting the design are considered as random variables and all the random variables are assumed to follow normal distribution. A computer program in C++ is developed to calculate the face widths in bending and surface failure modes. The larger one out of the two values is considered. By changing the variations in the design parameters, variations in the face widths are studied.

  16. Contactless Magnetic Gear for Robot Control Application

    Science.gov (United States)

    Komiyama, Hiroki; Uchimura, Yutaka

    This paper describes the application of a magnetic gear to a robot by fulfilling the essential requirements for a robot control, which are velocity control, position control, and force control. A magnetic gear is a transmission device that realizes contactless torque transmission by applying a magnetic force. When using a magnetic gear, cogging torque and spring characteristics need to be considered. In this paper, we introduce an approximate model of cogging torque. This model is used for velocity control to attenuate the disturbance due to cogging torque. In the case of position control, the oscillations due to the spring effect of the magnetic attractive force become a problem. To reduce the adverse effect due to these oscillations, resonance ratio control is applied. We also propose to use a magnetic gear for realizing the force sensorless bilateral control of teleoperation. Thanks to the frictionless transmission of a magnetic gear, the force sensorless estimation of a reaction force can be realized using a reaction force observer.

  17. Gear Transmission Error Measurement System Made Operational

    Science.gov (United States)

    Oswald, Fred B.

    2002-01-01

    A system directly measuring the transmission error between the meshing spur or helical gears was installed at the NASA Glenn Research Center and made operational in August 2001. This system employs light beams directed by lenses and prisms through gratings mounted on the two gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. The device is capable of resolution better than 0.1 mm (one thousandth the thickness of a human hair). The measured transmission error can be displayed in a "map" that shows how the transmission error varies with the gear rotation or it can be converted to spectra to show the components at the meshing frequencies. Accurate transmission error data will help researchers better understand the mechanisms that cause gear noise and vibration and will lead to The Design Unit at the University of Newcastle in England specifically designed the new system for NASA. It is the only device in the United States that can measure dynamic transmission error at high rotational speeds. The new system will be used to develop new techniques to reduce dynamic transmission error along with the resulting noise and vibration of aeronautical transmissions.

  18. American Orthopaedic Society for Sports Medicine

    Science.gov (United States)

    ... of Sports Medicine Sports Health: A Multidisciplinary Approach Orthopaedic Journal of Sports Medicine Journal Apps Sports Medicine ... Tweets by @AOSSM_SportsMed A world leader in Orthopaedic Sports Medicine Education, Research, Publishing, Communication and Fellowship ...

  19. SPORTS MARKETING AS A BUSINESS FUNCTION IN MODERN SPORTS

    OpenAIRE

    Danilo Aćimović; Omer Špirtović

    2013-01-01

    Discussion about sport marketing implies its theoretical definition and generalization, and then its actual definition in sport environment. Sport marketing, belongs to the newer type of the marketing. It appeared in time of increasing activity and significance of sport in the world. Huge human potential, with which sport as an activity disposes, implied the need to organize more properly and use it purposefully. “Sport marketing belongs to business function of sport organization and represen...

  20. Stuck in gear: age-related loss of variable gearing in skeletal muscle.

    Science.gov (United States)

    Holt, Natalie C; Danos, Nicole; Roberts, Thomas J; Azizi, Emanuel

    2016-04-01

    Skeletal muscles power a broad diversity of animal movements, despite only being able to produce high forces over a limited range of velocities. Pennate muscles use a range of gear ratios, the ratio of muscle shortening velocity to fiber shortening velocity, to partially circumvent these force-velocity constraints. Muscles operate with a high gear ratio at low forces; fibers rotate to greater angles of pennation, enhancing velocity but compromising force. At higher forces, muscles operate with a lower gear ratio; fibers rotate little so limiting muscle shortening velocity, but helping to preserve force. This ability to shift gears is thought to be due to the interplay of contractile force and connective tissue constraints. In order to test this hypothesis, gear ratios were determined in the medial gastrocnemius muscles of both healthy young rats, and old rats where the interaction between contractile and connective tissue properties was assumed to be disrupted. Muscle fiber and aponeurosis stiffness increased with age (Pmuscles, indicating that variable gearing is lost in old muscle. These findings support the hypothesis that variable gearing results from the interaction between contractile and connective tissues and suggest novel explanations for the decline in muscle performance with age.

  1. Two stage gear tooth dynamics program

    Science.gov (United States)

    Boyd, Linda S.

    1989-01-01

    The epicyclic gear dynamics program was expanded to add the option of evaluating the tooth pair dynamics for two epicyclic gear stages with peripheral components. This was a practical extension to the program as multiple gear stages are often used for speed reduction, space, weight, and/or auxiliary units. The option was developed for either stage to be a basic planetary, star, single external-external mesh, or single external-internal mesh. The two stage system allows for modeling of the peripherals with an input mass and shaft, an output mass and shaft, and a connecting shaft. Execution of the initial test case indicated an instability in the solution with the tooth paid loads growing to excessive magnitudes. A procedure to trace the instability is recommended as well as a method of reducing the program's computation time by reducing the number of boundary condition iterations.

  2. D Modelling with the Samsung Gear 360

    Science.gov (United States)

    Barazzetti, L.; Previtali, M.; Roncoroni, F.

    2017-02-01

    The Samsung Gear 360 is a consumer grade spherical camera able to capture photos and videos. The aim of this work is to test the metric accuracy and the level of detail achievable with the Samsung Gear 360 coupled with digital modelling techniques based on photogrammetry/computer vision algorithms. Results demonstrate that the direct use of the projection generated inside the mobile phone or with Gear 360 Action Direction (the desktop software for post-processing) have a relatively low metric accuracy. As results were in contrast with the accuracy achieved by using the original fisheye images (front and rear facing images) in photogrammetric reconstructions, an alternative solution to generate the equirectangular projections was developed. A calibration aimed at understanding the intrinsic parameters of the two lenses camera, as well as their relative orientation, allowed one to generate new equirectangular projections from which a significant improvement of geometric accuracy has been achieved.

  3. Thermal elastohydrodynamic lubrication of spur gears

    Science.gov (United States)

    Wang, K. L.; Cheng, H. S.

    1980-01-01

    An analysis and computer program called TELSGE were developed to predict the variations of dynamic load, surface temperature, and lubricant film thickness along the contacting path during the engagement of a pair of involute spur gears. The analysis of dynamic load includes the effect of gear inertia, the effect of load sharing of adjacent teeth, and the effect of variable tooth stiffness which are obtained by a finite-element method. Results obtained from TELSGE for the dynamic load distributions along the contacting path for various speeds of a pair of test gears show patterns similar to that observed experimentally. Effects of damping ratio, contact ratio, tip relief, and tooth error on the dynamic load were examined. In addition, two dimensionless charts are included for predicting the maximum equilibrium surface temperature, which can be used to estimate directly the lubricant film thickness based on well established EHD analysis.

  4. Jerky loads on surface-hardened gears

    Science.gov (United States)

    Rettig, H.; Wirth, X.

    1978-01-01

    Damage occurs again and again in practice in the form of transmissions with surface hardened gears which break after a very long operating time (explained by seldom occurring jerky loads). Gear drives are frequently exposed to jerky stresses which are greater than their fatigue limit. These stresses are considered in gear calculations, first, by shock factors when the transmission is to be designed as high endurance with regard to overloads and, second, in the form of operating ratios when the design is to be time enduring with regard to overloads. The size of the operating ratio depends not only on torque characteristics, drive and processing machine, but also on the material and heat treatment.

  5. 181 checklist and assessment of efficiency of some traditional gears ...

    African Journals Online (AJOL)

    CHECKLIST AND ASSESSMENT OF EFFICIENCY OF SOME TRADITIONAL. GEARS AND ... instruments while fishing. The gears were ..... Food and Agricultural Organization/United. Nations (1985). ... Fish Culture in undrainable ponds.

  6. 50 CFR 660.372 - Fixed gear sablefish fishery management.

    Science.gov (United States)

    2010-10-01

    ... limited entry permit with both a gear endorsement for longline or trap (or pot) gear and a sablefish... sablefish landing limit. This person must carry government issued photo identification while aboard the...

  7. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A major component of airframe noise for commercial transport aircraft is the deployed landing gear. The noise from the gear originates due to complex, unsteady bluff...

  8. Development of a high-performance magnetic gear

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Andersen, Torben Ole; Jørgensen, Frank Thorleif;

    2005-01-01

    This paper presents calculation and measurement results of a highperformance permanent-magnetic gear. The analyzed permanent-magnetic gear has a gear ratio of 5.5 and is able to deliver 27 N.m. The analysis has shown that special attention needs to be paid to the system where the gear...... is to be installed because of a low natural torsion spring constant. The analyzed gear was also constructed in practice in order to validate the analysis and predict the efficiency. The measured torque from the magnetic gear was only 16 N-m reduced by the large end-effects. A systematic analysis of the 1055...... in the bearings and jess end-effects caused by relative ly short stack, an impressive efficiency estimated at 96% can be obtained. Comparison with c1assical mechanical gears has shown that the magnetic gear has a bette r efficiency and a comparable torque per volume density. Finally, it is concluded...

  9. ANALYSIS OF TRANSMISSION CHARACTERISTICS OF COSINE GEAR DRIVE

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; LUO Shanming; CHEN Lifeng; CHEN Lei; HU Huarong

    2008-01-01

    Based on the mathematical model of a novel cosine gear drive, a few characteristics, such as the contact ratio, the sliding coefficient, and the contact and bending stresses, of this drive are analyzed. A comparison study of these characteristics with the involute gear drive is also carried out. The influences of design parameters including the number of teeth and the pressure angle on the contact and bending stresses are studied. The following conclusions are achieved: the contact ratio of the cosine gear drive is about 1.2 to 1.3, which is reduced by about 20% in comparison with that of the involute gear drive. The sliding coefficient of the cosine gear drive is smaller than that of the involute gear drive. The contact and bending stresses of the cosine gear drive are lower than those of the involute gear drive. The contact and bending stresses decrease with the growth of the number of teeth and the pressure angle.

  10. Design of aircraft turbine fan drive gear transmission system

    Science.gov (United States)

    Dent, E.; Hirsch, R. A.; Peterson, V. W.

    1970-01-01

    The following basic types of gear reduction concepts were studied as being feasible power train systems for a low-bypass-ratio, single-spool, geared turbofan engine for general aircraft use: (1) single-stage external-internal reduction, (2) gears (offset shafting), (3) multiple compound idler gear system (concentric shafting), and (4) star gear planetary system with internal ring gear final output member (concentric shafting-counterrotation). In addition, studies were made of taking the accessories drive power off both the high-speed and low-speed shafting, using either face gears or spiral bevel gears. Both antifriction and sleeve-type bearings were considered for the external-internal and star-planet reduction concepts.

  11. Profile modification to minimize spur gear dynamic loading

    Science.gov (United States)

    Lin, H. H.; Townsend, D. P.; Oswald, F. B.

    1989-01-01

    An analytical computer simulation program for dynamic modeling of low-contact-ratio spur gear systems is presented. The procedure computes the static transmission error of the gears operating under load and uses a fast Fourier transform to generate the frequency spectrum of the static transmission error at various tooth profile modifications. The dynamic loading response of an unmodified (perfect involute) gear pair was compared with that of gears with various profile modifications. Correlations were found between various profile modifications and the resulting dynamic loads. An effective error, obtained from frequency domain analysis of the static transmission error of the gears, gave a very good indication of the optimum profile modification to reduce gear dynamic loading. Design curves generated by dynamic simulation at various profile modifications are given for gear systems operated at various loads. Optimum profile modifications can be determined from these design curves for improved gear design.

  12. Data Fusion Tool for Spiral Bevel Gear Condition Indicator Data

    Science.gov (United States)

    Dempsey, Paula J.; Antolick, Lance J.; Branning, Jeremy S.; Thomas, Josiah

    2014-01-01

    Tests were performed on two spiral bevel gear sets in the NASA Glenn Spiral Bevel Gear Fatigue Test Rig to simulate the fielded failures of spiral bevel gears installed in a helicopter. Gear sets were tested until damage initiated and progressed on two or more gear or pinion teeth. During testing, gear health monitoring data was collected with two different health monitoring systems. Operational parameters were measured with a third data acquisition system. Tooth damage progression was documented with photographs taken at inspection intervals throughout the test. A software tool was developed for fusing the operational data and the vibration based gear condition indicator (CI) data collected from the two health monitoring systems. Results of this study illustrate the benefits of combining the data from all three systems to indicate progression of damage for spiral bevel gears. The tool also enabled evaluation of the effectiveness of each CI with respect to operational conditions and fault mode.

  13. Adventure and Extreme Sports.

    Science.gov (United States)

    Gomez, Andrew Thomas; Rao, Ashwin

    2016-03-01

    Adventure and extreme sports often involve unpredictable and inhospitable environments, high velocities, and stunts. These activities vary widely and include sports like BASE jumping, snowboarding, kayaking, and surfing. Increasing interest and participation in adventure and extreme sports warrants understanding by clinicians to facilitate prevention, identification, and treatment of injuries unique to each sport. This article covers alpine skiing and snowboarding, skateboarding, surfing, bungee jumping, BASE jumping, and whitewater sports with emphasis on epidemiology, demographics, general injury mechanisms, specific injuries, chronic injuries, fatality data, and prevention. Overall, most injuries are related to overuse, trauma, and environmental or microbial exposure.

  14. Marketing of sport tourism

    OpenAIRE

    A.S. Teletov; V.I. Karpets

    2015-01-01

    The aim of the article. The aim of the article is to clarify the concept of «sport tourism marketing», to examine the state of its objects and to determine prospects for development of sport tourism in Ukraine. The paper singles out the role of sport in life; compares different types of cities in terms of provision the infrastructure for tourism development in the field of sports. Authors show the example of the campaign. The results of the analysis. The article deals with sport tourism as...

  15. FUNCTION of MANAGEMENT IN SPORT

    Directory of Open Access Journals (Sweden)

    Srećko Novaković

    2011-03-01

    Full Text Available In the sport management coordination represents the basic deposit of management, and terms through numerous activities. Brother-in-law activity in sport has the specific management so speak about the management of sport event, management of sports facilities, management of management to the human activities, financial management in sport etc. The sportively management has presumed the specific management related to sports activities whose basic task of coordinations of sports activities. Management of sport organisations have been confided sport managers of special profile which differs towards the type of sport, rank of contest etc. The sport managers could utter survived the statement that in sport have not been educated special diameters manager, besides sport coaches. Specifically, in the role of manager in sport prevails almost all diameters of professional in professional or the volunteer relationship.

  16. [Sports in Luxembourg. The role of heart healthy sports].

    Science.gov (United States)

    Delagardelle, C

    2015-01-01

    , diabetes and CAD. It is noteworthy that the basic RF are more or less the same for the chronic diseases investigated in this study. Since the beginning of the new century PT has become an integral part of the strategies for cancer prevention and treatment. This option has been studied thoroughly first in breast cancer, later also in colon, prostate, and bronchial cancers etc. In primary prevention regular medium intensity training decreases the incidence of cancers by about 20-30%. For patients with proven cancers the application of PA as treatment option is more complicated compared to patients with cardiac problems since cancer patients often have to undergo surgery, then chemo- and/or irradiation therapy. All these interventions and their side effects have to be considered before applying PA. Above the physical alterations most cancer patients have to face anxiety and depression problems. PT improves the outcome between 15-25% and plays an important role in improving the psychological problems of the cancer patients. Since 10 years several oncologists in Luxembourg became interested in PA as a therapeutic option for their patients. They contacted the cardiologists and physiotherapists in charge of cardiac reeducation and progressively programs for PA in oncology were launched also in Luxembourg. Meanwhile several groups of cancer patients offer regular PT programs. In 2014 a stock concerning the different health sport activities in Luxembourg was taken by a young researcher of the Luxembourg Institute of health (LIH). 11 different associations are active; the most important and best organized are the cardiac sports groups, but there are also several oncologic, neurologic and orthopedic sports groups. A target for the coming years is to confer a robust infrastructure to all these associations following the model used by the cardiac groups. For the next year all these groups should be integrated into the Federation of Health Sports of the national Olympic Committee.

  17. Design, Modeling, Application and Analysis of Bevel Gears

    Directory of Open Access Journals (Sweden)

    1 Engr.Rufus Ogbuka Chime ,Mnse , Mnimech

    2016-04-01

    Full Text Available Computer technology has touched all areas of today’s life, impacting how we obtain railway tickets, shop online and receive medical advice from remote location. Computer-based design analysis is nowadays a common activity in most development projects. Traditionally, the design field has been identified with particular end products, e.g., mechanical design, electrical design, ship design. In these fields, design work is largely based on specific techniques to foster certain product characteristics and principles The scope of this work includes, to design, to model the bevel gear, to select gear materials , to detailed factor safety in design and to analysis bevel gears. Gears are toothed elements that transmit rotary motion from one shaft to another. Gears are generally rugged and durable and their power transmission efficiency is as high as 98%. Gears are usually more costly than chains and belts. Bevel gears are gears where the axes of the two shafts intersect and the toothbearing faces of the gears themselves are conically shaped. Bevel gears are most often mounted on shafts that are 90 degrees apart, but can be designed to work at other angles as well. The pitch surface of bevel gears is a cone. Two bevel gears in mesh is known as bevel gearing. In bevel gearing, the pitch cone angles of the pinion and gear are to be determined from the shaft angle, i.e., the angle between the intersecting shafts. The bevel gear has many diverse applications such as locomotives, marine applications, automobiles, printing presses, cooling towers, power plants, steel plants, railway track inspection machines, etc.

  18. New Design and Improvement of Planetary Gear Trains

    Science.gov (United States)

    Handschuh, Robert (Technical Monitor); Litvin, Faydor L.; Fuentes, Alfonso; Vecchiato, Daniele; Gonzalez-Perez, Ignacio

    2004-01-01

    The development of new types of planetary and planetary face-gear drives is proposed. The new designs are based on regulating backlash between the gears and modifying the tooth surfaces to improve the design. The goal of this work is to obtain a nearly uniform distribution of load between the planet gears. In addition, a new type of planetary face-gear drive was developed in this project.

  19. Methods for the Gear-Position Decision in AMT

    Institute of Scientific and Technical Information of China (English)

    孙以泽; 熊伟; 姚玉峰

    2003-01-01

    Aimed at defects of the gear-position decision in an automatic mechanical transmission, a method of synthetic shift schedule of 5-speed gear-position is presented, which is based on the fuzzy discernment of the driver intention and the road characteristics. A contrastive experimental analysis between the synthetic gear-position decision method and the traditional gear-position decision method is given by analyzing Santana 2000.

  20. Design and finite element mode analysis of noncircular gear

    OpenAIRE

    C. Lin; Cheng, K.; Qin, D.; Zhu, C.(); H. Qiu; Ran, X

    2008-01-01

    The noncircular gear transmission is an important branch of the gear transmission, it is characterized by its compact structure, good dynamic equilibration and other advantages, and can be used in the automobile, engineering machine, ship, machine tool, aviation and spaceflight field etc. Studying on the dynamics feature of noncircular gear transmission can improve the ability to carry loads of, reduce the vibration and noise of, increase the life of the noncircular gear transmission machine,...

  1. Vibration characteristics of single-stage planetary gear transmissions

    OpenAIRE

    Molina Vicuña,Cristián

    2014-01-01

    Condition monitoring based on vibration measurement and analysis of planetary gear transmissions has not provided the same good results observed in conventional fixed-shaft gear transmissions. One of the causes being the improper interpretation of the vibration spectrum. The structure of the lines present in the spectrum of the vibrations measured on a non-faulty planetary gear transmission, with a sensor mounted on the outer part of the ring gear, is strictly related to the geometry of the t...

  2. Research on the Design and Modification of Asymmetric Spur Gear

    OpenAIRE

    Xiaohe Deng; Lin Hua; Xinghui Han

    2015-01-01

    A design method for the geometric shape and modification of asymmetric spur gear was proposed, in which the geometric shape and modification of the gear can be obtained directly according to the rack-cutter profile. In the geometric design process of the gear, a rack-cutter with different pressure angles and fillet radius in the driving side and coast side was selected, and the generated asymmetric spur gear profiles also had different pressure angles and fillets accordingly. In the modificat...

  3. Mathematical Modelling of Involute Spur Gears Manufactured by Rack Cutter

    Directory of Open Access Journals (Sweden)

    Tufan Gürkan YILMAZ

    2016-05-01

    Full Text Available In this study, mathematical modelling of asymmetric involute spur gears was situated in by Litvin approach. In this context, firstly, mathematical expressions of rack cutter which manufacture asymmetric involute spur gear, then mathematical expression of asymmetric involute spur gear were obtained by using differential geometry, coordinate transformation and gear theory. Mathematical expressions were modelled in MATLAB and output files including points of involute spur gear’s teeth were designed automatically thanks to macros.

  4. EXHIBITION VISIBILITY; case Moventas Gears Ltd Service WG division

    OpenAIRE

    Elijärvi, Maaret

    2014-01-01

    Wind power business has been developing rapidly during last 10 years and turbines are sprouting up around the globe in record numbers. Moventas Gears Oy is one of the suppliers to the global wind turbine industry. Moventas Gears Oy has two different divisions on wind gear business, new manufacturing (CAP) and service (SER) divisions. The purpose of this work is to improve Moventas Gears Wind Service (SER) marketing visibility and as a target was taken exhibitions. In this work, will be co...

  5. Technology and Sport

    DEFF Research Database (Denmark)

    Møller, Rasmus Bysted; Møller, Verner

    2015-01-01

    The relationship between sport and technology is close and can be both fruitful and destructive. Technology has a constitutive function in sport as it makes the activity possible and it can enhance performance as well as the sporting experience. The use of football boots is clearly more comfortable...... and effective than playing in bare feet in a game of football. However, sport challenges its athletes by demanding the employment of less efficient means rather than more efficient means in pursuit of sport specific goals. Therefore technology can potentially subtract from the sporting experience and even...... threaten the internal logic of sport. If as an example very efficient hail cartridges were allowed for use in double trap shooting it would reduce the skills required to excel at that discipline reducing its value for participants and spectators alike. The use of forbidden performance enhancing substances...

  6. Is Sport Nationalism Justifiable?

    Directory of Open Access Journals (Sweden)

    José Luis Pérez Triviño

    2015-07-01

    Full Text Available The article aims to clarify the deep relationships established between sport and nationalism by considering, among other factors, the instrumentalisation of sport by political elites, political apathy of citizens, economic resources for sport, the question of violence or identitarian matters. In order to define if the combination of sport and nationalism is admissible, the paper defines sport nationalism and distinguishes the political use of sport for purposes of domestic and foreign policy. In the first section the analysis focuses on whether a causal link with respect to the contribution to violence can be established and with respect to its use in the internal politics of a state, the paper differentiates between normal political circumstances and political crises in order to properly address the question of whether there are grounds to assert that sport can distract citizens from asserting their genuine interests.

  7. Is Sport Nationalism Justifiable?

    Directory of Open Access Journals (Sweden)

    José Luis Pérez Triviño

    2012-01-01

    Full Text Available The article aims to clarify the deep relationships established between sport and nationalism by considering, among other factors, the instrumentalisation of sport by political elites, political apathy of citizens, economic resources for sport, the question of violence or identitarian matters. In order to define if the combination of sport and nationalism is admissible, the paper defines sport nationalism and distinguishes the political use of sport for purposes of domestic and foreign policy. In the first section the analysis focuses on whether a causal link with respect to the contribution to violence can be established and with respect to its use in the internal politics of a state, the paper differentiates between normal political circumstances and political crises in order to properly address the question of whether there are grounds to assert that sport can distract citizens from asserting their genuine interests.

  8. Sport and migrants' acculturation

    DEFF Research Database (Denmark)

    Morela, Eleftheria

    was to explore the acculturation attitudes of Greek adolescents as a function of sport participation, and, for those participating in sport, to investigate the role of the motivationalenvironment. The results showed that athletes scored higher than non-athletes on attitudes towards multicultural contact...... multiculturalism. Sport is considered to be a vehicle for bringing people together, and recently there has been an increasing policy interest in the use of sport as a venue for promoting social integration and intercultural dialogue. Regardless of its political significance, research on the integrative role...... of sport is limited and findings seem equivocal. Overall the purpose of the present study was to investigate whether participation in organized sport can affect the acculturation process of young adolescents from both minority and majority populations in Greece, and to explore features ofthe sporting...

  9. Global Analysis of a Planetary Gear Train

    OpenAIRE

    Tongjie Li; Rupeng Zhu

    2014-01-01

    By using the Poincaré-like cell-to-cell mapping method and shooting method, the global characteristics of a planetary gear train are studied based on the torsional vibration model with errors of transmission, time-varying meshing stiffness, and multiple gear backlashes. The study results reveal that the planetary with a certain set of parameters has four coexisting periodic orbits, which are P-1, P-2, P-4, and P-8, respectively. P-1 and P-2 motions are not of long-term stability, P-8 motion ...

  10. THE SPORT MARKETING MANAGEMENT MODEL

    OpenAIRE

    Alexandru Lucian MIHAI

    2015-01-01

    Sport marketing involves marketing fundamentals applied in one industry, the sport business industry. The development of sport marketing fundamentals is therefore based on basic marketing principles. The practice and activities of sport marketing are also based on basic marketing activities, but are modified and adapted to the sport business industry. Therefore, sport marketing is based on its primary and parent discipline - marketing. Sport marketing is one of the most important function...

  11. THE SPORT MARKETING MANAGEMENT MODEL

    OpenAIRE

    Alexandru Lucian MIHAI

    2015-01-01

    Sport marketing involves marketing fundamentals applied in one industry, the sport business industry. The development of sport marketing fundamentals is therefore based on basic marketing principles. The practice and activities of sport marketing are also based on basic marketing activities, but are modified and adapted to the sport business industry. Therefore, sport marketing is based on its primary and parent discipline - marketing. Sport marketing is one of the most important function...

  12. Return to sport following anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Feller, Julian; Webster, Kate E

    2013-02-01

    Rates of return to pre-injury sport following anterior cruciate ligament (ACL) reconstruction are less than might be expected from standard outcome measures and there appears to be a rapid decline in sporting participation after two to three years. There are many factors that influence whether an individual will return to sport following this type of surgery. They include not only surgical details and rehabilitation, but also social and psychological factors, as well as demographic characteristics. Age is of particular importance with older patients being less likely to resume their pre-injury sport. It is important that future research clearly identify the pre-injury characteristics of the study cohort when investigating return to sport, and also that there is consistent and precise terminology used to report rates of return to sporting activities. Little is known about how to determine when it is safe to return to sport following ACL reconstruction or how to predict whether an athlete will be able to successfully return to sport. Finally, it needs to be recognised that return to sport following ACL reconstruction is associated with a risk of further injury and the development of osteoarthritis.

  13. Effects of gear box vibration and mass imbalance on the dynamics of multi-stage gear transmissions

    Science.gov (United States)

    Choy, Fred K.; Tu, Yu K.; Zakrajsek, James J.; Townsend, Dennis P.

    1991-01-01

    The dynamic behavior of multistage gear transmission system, with the effects of gear-box-induced vibrations and rotor mass-imbalances is analyzed. The model method, using undamped frequencies and planar mode shapes, is used to reduce the degree-of-freedom of the system. The various rotor-bearing stages as well as lateral and torsional vibrations of each individual stage are coupled through localized gear-mesh-tooth interactions. Gear-box vibrations are coupled to the gear stage dynamics through bearing support forces. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domain. A typical three-staged geared system is used as an example. Effects of mass-imbalance and gear box vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  14. Performance of polymer gears reinforced with sisal woven rovings

    Directory of Open Access Journals (Sweden)

    A. Faizur Rahman

    2014-12-01

    Full Text Available Polymer gears find a common place in many industries and applications. In general, carbon fibre and glass fibres are used as reinforcement in polymer gears. This current research focuses on developing and testing the temperature and wear performance of Polyester spur gears reinforced with Sisal Woven Rovings (SWRP . Volume fractions (Vf such as 5% (SWRP/A, 10% (SWRP/B, 15% (SWRP/C and 20% (SWRP/D of gear specimens were prepared and tested for temperature and wear effects. Gears were tested up to 1.4 x 106 cycles. Gear tooth damages are recorded through optical photographs. The result reveals that the temperature and wear performance of SWRP/A and SWRP/B gears were low compared to SWRP/D gears.A small amount of wear damages were observed in SWRP/C gears. No damages were occurred in SWRP/D gears upto 1.4 x 106 cycles and also it was observed that the temperature and wear rate were found to be 15 % and 36 % lesser in SWRP/D gears when compared to SWRP/A gears.

  15. 46 CFR 58.25-20 - Piping for steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... actuating system including the reservoir. The storage tank must be permanently connected by piping so...

  16. 46 CFR 61.20-1 - Steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  17. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  18. 29 CFR 1915.116 - Use of gear.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Use of gear. 1915.116 Section 1915.116 Labor Regulations...) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Gear and Equipment for Rigging and Materials Handling § 1915.116 Use of gear. (a) The provisions of this section shall apply to ship...

  19. 46 CFR 182.610 - Main steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  20. 46 CFR 167.65-25 - Steering gear tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  1. Molecular dynamics simulations of carbon nanotube-based gears

    Science.gov (United States)

    Han, Jie; Globus, Al; Jaffe, Richard; Deardorff, Glenn

    1997-09-01

    We use a molecular dynamics simulation to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with 0957-4484/8/3/001/img1. Brenner's reactive hydrocarbon potential is used to model interatomic forces within each molecular gear. A Lennard - Jones 6 - 12 potential or the Buckingham 0957-4484/8/3/001/img2 potential plus electrostatic interaction terms are used for intermolecular interactions between gears. A number of gear and gear/shaft configurations are simulated on parallel computers. One gear is powered by forcing the atoms near the end of the nanotube to rotate, and a second gear is allowed to rotate by keeping the atoms near the end of its nanotube constrained to a cylinder. The meshing aromatic gear teeth transfer angular momentum from the powered gear to the driven gear. Results suggest that these gears can operate at up to 50 - 100 GHz in a vacuum at room temperature. The failure mode involves tooth slip, not bond breaking, so failed gears can be returned to operation by lowering the temperature and/or rotation rate.

  2. 50 CFR 640.22 - Gear and diving restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear and diving restrictions. 640.22 Section 640.22 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ATLANTIC Management Measures § 640.22 Gear and diving restrictions. (a) Prohibited gear and methods. (1)...

  3. Performances of a balanced hydraulic motor with planetary gear train

    Science.gov (United States)

    Yu, Hongying; Luo, Changjie; Wang, Huimin

    2012-07-01

    The current research of a balanced hydraulic motor focuses on the characteristics of the motor with three planet gears. References of a balanced hydraulic motor with more than three planet gears are hardly found. In order to study the characteristics of a balanced hydraulic motor with planetary gear train that includes more than three planet gears, on the basis of analysis of the structure and working principle of a balanced hydraulic motor with planetary gear train, formulas are deduced for calculating the hydraulic motor's primary performance indexes such as displacement, unit volume displacement, flowrate fluctuation ratio, etc. Influences of the gears' tooth number on displacement and flowrate characteristics are analyzed. In order to guarantee the reliability of sealing capability, the necessary conditions that tooth number of the sun gear and the planet gears should satisfy are discussed. Selecting large unit volume displacement and small displacement fluctuation ratio as designing objectives, a balanced hydraulic motor with three planet gears and a common gear motor are designed under the conditions of same displacement, tooth addendum coefficien and clearance coefficient. By comparing the unit volume displacement and fluctuation ratio of the two motors, it can be seen that the balanced hydraulic motor with planetary gear train has the advantages of smaller fluctuation ratio and larger unit volume displacement. The results provide theoretical basis for choosing gear tooth-number of this kind of hydraulic motor.

  4. A fabrication process for electrostatic microactuators with integrated gear linkages

    NARCIS (Netherlands)

    Legtenberg, Rob; Berenschot, Erwin; Elwenspoek, Miko; Fluitman, Jan H.

    1997-01-01

    A surface micromachining process is presented which has been used to fabricate electrostatic microactuators. These microactuators are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear struct

  5. 50 CFR 600.510 - Gear avoidance and disposal.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear avoidance and disposal. 600.510 Section 600.510 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Gear avoidance and disposal. (a) Vessel and gear avoidance. (1) FFV's arriving on fishing grounds...

  6. Molecular Dynamics Simulation of Carbon Nanotube Based Gears

    Science.gov (United States)

    Han, Jie; Globus, Al; Jaffe, Richard; Deardorff, Glenn; Chancellor, Marisa K. (Technical Monitor)

    1996-01-01

    We used molecular dynamics to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. One gear was powered by forcing the atoms near the end of the buckytube to rotate, and a second gear was allowed.to rotate by keeping the atoms near the end of its buckytube on a cylinder. The meshing aromatic gear teeth transfer angular momentum from the powered gear to the driven gear. A number of gear and gear/shaft configurations were simulated. Cases in vacuum and with an inert atmosphere were examined. In an extension to molecular dynamics technology, some simulations used a thermostat on the atmosphere while the hydrocarbon gear's temperature was allowed to fluctuate. This models cooling the gears with an atmosphere. Results suggest that these gears can operate at up to 50-100 gigahertz in a vacuum or inert atmosphere at room temperature. The failure mode involves tooth slip, not bond breaking, so failed gears can be returned to operation by lowering temperature and/or rotation rate. Videos and atomic trajectory files in xyz format are presented.

  7. Molecular Dynamics Simulation of Carbon Nanotube Based Gears

    Science.gov (United States)

    Han, Jie; Globus, Al; Jaffe, Richard; Deardorff, Glenn; Chancellor, Marisa K. (Technical Monitor)

    1996-01-01

    We used molecular dynamics to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. One gear was powered by forcing the atoms near the end of the buckytube to rotate, and a second gear was allowed.to rotate by keeping the atoms near the end of its buckytube on a cylinder. The meshing aromatic gear teeth transfer angular momentum from the powered gear to the driven gear. A number of gear and gear/shaft configurations were simulated. Cases in vacuum and with an inert atmosphere were examined. In an extension to molecular dynamics technology, some simulations used a thermostat on the atmosphere while the hydrocarbon gear's temperature was allowed to fluctuate. This models cooling the gears with an atmosphere. Results suggest that these gears can operate at up to 50-100 gigahertz in a vacuum or inert atmosphere at room temperature. The failure mode involves tooth slip, not bond breaking, so failed gears can be returned to operation by lowering temperature and/or rotation rate. Videos and atomic trajectory files in xyz format are presented.

  8. Electrostatic microactuators with integrated gear linkages for mechanical power transmission

    NARCIS (Netherlands)

    Legtenberg, R.; Berenschot, J.W.; Elwenspoek, M.C.; Fluitman, J.H.J.

    1996-01-01

    In this paper a surface micromachining process is presented which has been used to fabricate electrostatic microactuators that are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear structure

  9. Gear cutting tools fundamentals of design and computation

    CERN Document Server

    Radzevich, Stephen P

    2010-01-01

    Presents the DG/K-based method of surface generation, a novel and practical mathematical method for designing gear cutting tools with optimal parameters. This book proposes a scientific classification for the various kinds of the gear machining meshes, discussing optimal designs of gear cutting tools.

  10. SPORTS MARKETING AS A BUSINESS FUNCTION IN MODERN SPORTS

    Directory of Open Access Journals (Sweden)

    Danilo Aćimović

    2013-07-01

    Full Text Available Discussion about sport marketing implies its theoretical definition and generalization, and then its actual definition in sport environment. Sport marketing, belongs to the newer type of the marketing. It appeared in time of increasing activity and significance of sport in the world. Huge human potential, with which sport as an activity disposes, implied the need to organize more properly and use it purposefully. “Sport marketing belongs to business function of sport organization and represents primarily an economical process of connecting production (sport organizations with sportsmen and coaches and consumption (sport and other public. It can be seen in the fact besides promoting sport it conducts certain (limited productive activity (exchange of sport equipment, exchange of sport requisites and material goods that create sport clubs through competitions.

  11. Enhancement in Sport, and Enhancement outside Sport

    OpenAIRE

    Douglas, Thomas

    2007-01-01

    Sport is one of the first areas in which enhancement has become commonplace. It is also one of the first areas in which the use of enhancement technologies has been heavily regulated. Some have thus seen sport as a testing ground for arguments about whether to permit enhancement. However, I argue that there are fairness-based objections to enhancement in sport that do not apply as strongly in some other areas of human activity. Thus, I claim that there will often be a stronger case for permit...

  12. Relationship between Sport Nourishment Supplement and Athletes' Sports Abilities

    Directory of Open Access Journals (Sweden)

    Mingjiang Zhu

    2015-06-01

    Full Text Available It is very important for the athlete's body recovery and rehabilitation to have sport nourishment supplement. In this study, it analyzed the effect of sport nourishment supplement with the overview of sport nourishment supplements, discussing the influence of sports nutrition supplement on sports abilities of athletes.

  13. Comparison of eSports and Traditional Sports Consumption Motives

    Science.gov (United States)

    Lee, Donghun; Schoenstedt, Linda J.

    2011-01-01

    With recognition of the need for studying eSports in this interactive digital communication era, this study explored 14 motivational factors affecting the time spent on eSports gaming. Using a sample of 515 college students and athletic event attendees, we further compared eSports game patterns to their non-eSport or traditional sport involvements…

  14. Dynamic load sharing characteristics and sun gear radial orbits of double-row planetary gear train

    Institute of Scientific and Technical Information of China (English)

    盛冬平; 朱如鹏; 靳广虎; 陆凤霞; 鲍和云

    2015-01-01

    A new non-linear bending-torsional coupled model for double-row planetary gear set was proposed, and planet’s eccentricity error, static transmission error, and time-varying meshing stiffness were taken into consideration. The solution of differential governing equation of motion is determined by applying the Fourier series method. The behaviors of dynamic load sharing characteristics affected by the system parameters including gear eccentricities error, ring gear’s supporting stiffness, planet’s bearing stiffness, torsional stiffness of first stage carrier and input rotation rate were investigated qualitatively and systematically, and sun gear radial orbits at first and second stage were explored as well. Some theoretical results are summarized as guidelines for further research and design of double-row planetary gear train at last.

  15. [Sport and rheumatoid arthritis].

    Science.gov (United States)

    Proschek, D; Rehart, S

    2014-06-01

    Sport is becoming increasingly more important in our society. Due to the changing age spectrum with a greater number of elderly and substantially more active people, an increasing number of people with underlying orthopedic diseases are becoming interested in participating in sport. This article deals with the possibilities and effects of sporting activities for people with rheumatoid arthritis within the framework of a conservative therapy. A literature search was carried out using medical search engines, in particular PubMed, and also via the recommendations of specialist societies and patient help groups. The quality of life of patients with rheumatoid arthritis consists of physical, mental and social components. Sport as a means of rehabilitation influences all of these components. Sport should be comprehended as a form of therapy and be adapted to the needs of the individual patient. The willingness to actively participate in sport should always be highly rated and encouraged. Sport is therefore an important pillar of therapy in a conservative total concept. The main aspects of sport therapeutic activities are functional, pedagogical and experience-oriented aspects. The clinical symptoms, extent of damage and physical impairment must, however, be evaluated and taken into consideration for the therapeutic concept. The amount of data on the complex topic of sport and rheumatoid arthritis is low and is mainly dealt with as retrospective reviews. A prospective randomized study basis is lacking. The aim must therefore be to confirm the currently available recommendations for various types of sport in controlled studies.

  16. GEAR UP: Providing Opportunities or Conflict?

    Science.gov (United States)

    Walsh, Rachael

    2008-01-01

    Since 1965 the federal government has attempted to provide low socioeconomic status students with equal access to postsecondary education through the Higher Education Act and its multiplicative programmatic efforts. Implemented as one such program in 1998, the Gaining Early Awareness and Readiness for Undergraduate Programs, or GEAR UP, has been…

  17. Design and transient behavior of magnetic gears

    Science.gov (United States)

    Zheng, Ping; Bai, Jingang; Lin, Jia; Fu, Zhenxing; Song, Zhiyi; Lin, Fei

    2014-05-01

    The torque density is a key factor for magnetic gears. To obtain maximum torque density, the design principle of magnetic gears is proposed and the maximum transmitting torque is investigated under different combinations of the inner and outer permanent magnets (PM) rotor pole pairs. The research proves that the maximum transmitting torque and the minimum torque ripple can be obtained only when the ratio of the outer and inner PM pole pair numbers is fractional. Then, the optimal selection of the span ratio and thickness of magnetic blocks in the stationary modulating ring is investigated to obtain the maximum torque. Meanwhile, analyses of the losses of various parts in the magnetic gear show that the loss of the PMs is about 70% of the total losses. Therefore, the method of dividing the PM into several pieces along the circumferential direction is employed to reduce the PM loss, which makes the PM loss reduced by 73%. Additionally, the transient behavior of the magnetic gear is analyzed, indicating that the lower torsional stiffness is the main reason for oscillations during transient changes in speed and load. To suppress oscillations due to transients, damper windings are employed and the transient time and the maximum oscillation amplitude are reduced by 25% and 20%, respectively.

  18. Detecting Tooth Damage in Geared Drive Trains

    Science.gov (United States)

    Nachtsheim, Philip R.

    1997-01-01

    This paper describes a method that was developed to detect gear tooth damage that does not require a priori knowledge of the frequency characteristic of the fault. The basic idea of the method is that a few damaged teeth will cause transient load fluctuations unlike the normal tooth load fluctuations. The method attempts to measure the energy in the lower side bands of the modulated signal caused by the transient load fluctuations. The method monitors the energy in the frequency interval which excludes the frequency of the lowest dominant normal tooth load fluctuation and all frequencies above it. The method reacted significantly to the tooth fracture damage results documented in the Lewis data sets which were obtained from tests of the OH-58A transmission and tests of high contact ratio spiral bevel gears. The method detected gear tooth fractures in all four of the high contact ratio spiral bevel gear runs. Published results indicate other detection methods were only able to detect faults for three out of four runs.

  19. Energy efficiency improvement by gear shifting optimization

    Directory of Open Access Journals (Sweden)

    Blagojevic Ivan A.

    2013-01-01

    Full Text Available Many studies have proved that elements of driver’s behavior related to gear selection have considerable influence on the fuel consumption. Optimal gear shifting is a complex task, especially for inexperienced drivers. This paper presents an implemented idea for gear shifting optimization with the aim of fuel consumption minimization with more efficient engine working regimes. Optimized gear shifting enables the best possible relation between vehicle motion regimes and engine working regimes. New theoretical-experimental approach has been developed using On-Board Diagnostic technology which so far has not been used for this purpose. The matrix of driving modes according to which tests were performed is obtained and special data acquisition system and analysis process have been developed. Functional relations between experimental test modes and adequate engine working parameters have been obtained and all necessary operations have been conducted to enable their use as inputs for the designed algorithm. The created Model has been tested in real exploitation conditions on passenger car with Otto fuel injection engine and On-Board Diagnostic connection without any changes on it. The conducted tests have shown that the presented Model has significantly positive effects on fuel consumption which is an important ecological aspect. Further development and testing of the Model allows implementation in wide range of motor vehicles with various types of internal combustion engines.

  20. Catastrophic Cervical Spine Injuries in Contact Sports.

    Science.gov (United States)

    Hutton, Michael James; McGuire, Robert A; Dunn, Robert; Williams, Richard; Robertson, Peter; Twaddle, Bruce; Kiely, Patrick; Clarke, Andrew; Mazda, Keyvan; Davies, Paul; Pagarigan, Krystle T; Dettori, Joseph R

    2016-11-01

    Study Design Systematic review. Objectives To determine the incidence of catastrophic cervical spine injuries (CCSIs) among elite athletes participating in contact team sports and whether the incidence varies depending on the use of protective gear or by player position. Methods Electronic databases and reference lists of key articles published from January 1, 2000, to January 29, 2016, were searched. Results Fourteen studies were included that reported CCSI in rugby (n = 10), American football (n = 3), and Irish hurling (n = 1). Among Rugby Union players, incidence of CCSI was 4.1 per 100,000 player-hours. Among National Football League players, the CCSI rate was 0.6 per 100,000 player-exposures. At the collegiate level, the CCSI rate ranged from 1.1 to 4.7 per 100,000 player-years. Mixed populations of elite and recreational rugby players in four studies report a CCSI rate of 1.4 to 7.2 per 100,000 player-years. In this same population, the scrum accounted for 30 to 51% of total reported CCSIs in Rugby Union versus 0 to 4% in Rugby League. The tackle accounted for 29 to 39% of injuries in Rugby Union and 78 to 100% of injuries in Rugby League. Making a tackle was responsible for 29 to 80% of injuries in American football. Conclusion CCSIs are infrequent among elite athletes. There is insufficient evidence to determine the effect of protective gear (e.g., helmets, padding) on CCSI incidence. Scrum and tackle in rugby and tackling in American football account for the majority of CCSIs in each respective sport.

  1. Catastrophic Cervical Spine Injuries in Contact Sports

    Science.gov (United States)

    Hutton, Michael James; McGuire, Robert A.; Dunn, Robert; Williams, Richard; Robertson, Peter; Twaddle, Bruce; Kiely, Patrick; Clarke, Andrew; Mazda, Keyvan; Davies, Paul; Pagarigan, Krystle T.; Dettori, Joseph R.

    2016-01-01

    Study Design Systematic review. Objectives To determine the incidence of catastrophic cervical spine injuries (CCSIs) among elite athletes participating in contact team sports and whether the incidence varies depending on the use of protective gear or by player position. Methods Electronic databases and reference lists of key articles published from January 1, 2000, to January 29, 2016, were searched. Results Fourteen studies were included that reported CCSI in rugby (n = 10), American football (n = 3), and Irish hurling (n = 1). Among Rugby Union players, incidence of CCSI was 4.1 per 100,000 player-hours. Among National Football League players, the CCSI rate was 0.6 per 100,000 player-exposures. At the collegiate level, the CCSI rate ranged from 1.1 to 4.7 per 100,000 player-years. Mixed populations of elite and recreational rugby players in four studies report a CCSI rate of 1.4 to 7.2 per 100,000 player-years. In this same population, the scrum accounted for 30 to 51% of total reported CCSIs in Rugby Union versus 0 to 4% in Rugby League. The tackle accounted for 29 to 39% of injuries in Rugby Union and 78 to 100% of injuries in Rugby League. Making a tackle was responsible for 29 to 80% of injuries in American football. Conclusion CCSIs are infrequent among elite athletes. There is insufficient evidence to determine the effect of protective gear (e.g., helmets, padding) on CCSI incidence. Scrum and tackle in rugby and tackling in American football account for the majority of CCSIs in each respective sport. PMID:27781193

  2. Analytical and experimental study of vibrations in a gear transmission

    Science.gov (United States)

    Choy, F. K.; Ruan, Y. F.; Zakrajsek, J. J.; Oswald, F. B.; Coy, J. J.

    1991-01-01

    An analytical simulation of the dynamics of a gear transmission system is presented and compared to experimental results from a gear noise test rig at NASA Lewis. The analytical procedure developed couples the dynamic behaviors of the rotor-bearing-gear system with the response of the gearbox structure. Transient and steady-state vibrations of the gearbox system are presented in the time and frequency domains. The vibration characteristics of a simple single-mesh-gear noise test rig are modeled. The numerical simulations are compared to experimental data measured under typical operating conditions. The system natural frequencies, peak vibration amplitudes, and gear mesh frequencies are generally in good agreement.

  3. Effects of rim thickness on spur gear bending stress

    Science.gov (United States)

    Bibel, G. D.; Reddy, S. K.; Savage, M.; Handschuh, R. F.

    1991-01-01

    Thin rim gears find application in high-power, light-weight aircraft transmissions. Bending stresses in thin rim spur gear tooth fillets and root areas differ from the stresses in solid gears due to rim deformations. Rim thickness is a significant design parameter for these gears. To study this parameter, a finite element analysis was conducted on a segment of a thin rim gear. The rim thickness was varied and the location and magnitude of the maximum bending stresses reported. Design limits are discussed and compared with the results of other researchers.

  4. Thyroid Surgery

    Science.gov (United States)

    ... Fax/Phone Home » Thyroid Surgery Leer en Español Thyroid Surgery GENERAL INFORMATION Your doctor may recommend that ... made in conjunction with your endocrinologist and surgeon. Thyroid Surgery FAQs QUESTIONS AND CONSIDERATIONS When thyroid surgery ...

  5. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  6. Sports Medicine: What is a Sports Medicine Specialist?

    Science.gov (United States)

    ... both the treatment and prevention of illness and injury. The Sports Medicine Specialist helps patients maximize function and minimize ... of these conditions. However, approximately 90% of all sports injuries are non-surgical. The Sports Medicine Specialist can ...

  7. The importance of sport psychology in school sport | le Roux ...

    African Journals Online (AJOL)

    The importance of sport psychology in school sport. ... of values associated with sport, the prevention of burnout in a young athlete, how to ... These findings can mainly be attributed to a lack of knowledge regarding the psychology of the child.

  8. RDS-21 Face-Gear Surface Durability Tests

    Science.gov (United States)

    Lewicki, David G.; Heath, Gregory F.; Filler, Robert R.; Slaughter, Stephen C.; Fetty, Jason

    2007-01-01

    Experimental fatigue tests were performed to determine the surface durability life of a face gear in mesh with a tapered spur involute pinion. Twenty-four sets of gears were tested at three load levels: 7200, 8185, and 9075 lb-in face gear torque, and 2190 to 3280 rpm face gear speed. The gears were carburized and ground, shot-peened and vibro-honed, and made from VIM-VAR Pyrowear 53 steel per AMS 6308. The tests produced 17 gear tooth spalling failures and 7 suspensions. For all the failed sets, spalling occurred on at least one tooth of all the pinions. In some cases, the spalling initiated a crack in the pinion teeth which progressed to tooth fracture. Also, spalling occurred on some face gear teeth. The AGMA endurance allowable stress for a tapered spur involute pinion in mesh with a face gear was determined to be 275 ksi for the material tested. For the application of a tapered spur involute pinion in mesh with a face gear, proper face gear shim controlled the desired gear tooth contact pattern while proper pinion shim was an effective way of adjusting backlash without severely affecting the contact pattern.

  9. Research on the Design and Modification of Asymmetric Spur Gear

    Directory of Open Access Journals (Sweden)

    Xiaohe Deng

    2015-01-01

    Full Text Available A design method for the geometric shape and modification of asymmetric spur gear was proposed, in which the geometric shape and modification of the gear can be obtained directly according to the rack-cutter profile. In the geometric design process of the gear, a rack-cutter with different pressure angles and fillet radius in the driving side and coast side was selected, and the generated asymmetric spur gear profiles also had different pressure angles and fillets accordingly. In the modification design of the gear, the pressure angle modification of rack-cutter was conducted firstly and then the corresponding modified involute gear profile was obtained. The geometric model of spur gears was developed using computer-aided design, and the meshing process was analyzed using finite element simulation method. Furthermore, the transmission error and load sharing ratio of unmodified and modified asymmetric spur gears were investigated. Research results showed that the proposed gear design method was feasible and desired spur gear can be obtained through one time rapid machining by the method. Asymmetric spur gear with better transmission characteristic can be obtained via involute modification.

  10. Dynamics of High-Speed Precision Geared Rotor Systems

    Directory of Open Access Journals (Sweden)

    Lim Teik C.

    2014-07-01

    Full Text Available Gears are one of the most widely applied precision machine elements in power transmission systems employed in automotive, aerospace, marine, rail and industrial applications because of their reliability, precision, efficiency and versatility. Fundamentally, gears provide a very practical mechanism to transmit motion and mechanical power between two rotating shafts. However, their performance and accuracy are often hampered by tooth failure, vibrations and whine noise. This is most acute in high-speed, high power density geared rotor systems, which is the primary scope of this paper. The present study focuses on the development of a gear pair mathematical model for use to analyze the dynamics of power transmission systems. The theory includes the gear mesh representation derived from results of the quasi-static tooth contact analysis. This proposed gear mesh theory comprising of transmission error, mesh point, mesh stiffness and line-of-action nonlinear, time-varying parameters can be easily incorporated into a variety of transmission system models ranging from the lumped parameter type to detailed finite element representation. The gear dynamic analysis performed led to the discovery of the out-of-phase gear pair torsion modes that are responsible for much of the mechanical problems seen in gearing applications. The paper concludes with a discussion on effectual design approaches to minimize the influence of gear dynamics and to mitigate gear failure in practical power transmission systems.

  11. Dynamic Modelling and Analysis of the Microsegment Gear

    Directory of Open Access Journals (Sweden)

    Yangshou Xiong

    2016-01-01

    Full Text Available The development of technology requires higher load capacity, rotating speed, power-weight ratio, lower vibration, and noise with respect to the gear transmission. The new type microsegment gear’s tooth profile curve is composed of many microsegments. Previous researches indicate that the microsegment gear has a good static performance, while the dynamic behavior of the microsegment gear has never been investigated. This paper will focus on the dynamic performance of the gear. The profile deviation between microsegment gear and involute gear is regarded as a displacement excitation in the proposed dynamic model. The numerical analysis for three cases is conducted and the results shows that, in low-speed and heavy-load, medium-speed and medium-load conditions, microsegment gear and involute gear both exhibit a good performance, while, in high-speed and heavy-load condition, microsegment gear has a better performance than that of involute gear. The influence of backlash on the dynamic performance is also studied. It is found that the variation of backlash does not change the type of motion, but the vibration amplitude and the stability of the motion are much affected. The main idea in this paper is supposed to provide a novel method for the precision grinding of the microsegment gear.

  12. Gear Durability Shown To Be Improved by Superfinishing

    Science.gov (United States)

    Krautz, Timothy L.

    2000-01-01

    Gears, bearings, and similar mechanical elements transmit loads through contacting surfaces. At the NASA Glenn Research Center at Lewis Field, we postulated that the fatigue lives of gears could be improved by providing smoother tooth surfaces. A superfinishing process was applied to a set of conventionally ground, aerospace-quality gears. This process produced a highly polished, mirrorlike surface as shown in the preceding photograph. The surface fatigue lives of both superfinished and conventionally ground gears were measured by experiments. The superfinished gears survived about four times longer than the conventionally ground gears. These superfinished gears were produced from conventionally ground, aerospace-quality gears whose geometry had been inspected. The gears were superfinished by placing them in a vibrating bath consisting of water, detergent, abrasive powder, and small pieces of zinc. Upon removal from the bath, the surfaces were highly polished, as depicted in the preceding photograph. The gears were again inspected, and dimensional measurements made before and after the superfinishing operation were compared. Superfinishing removed the peaks of the grinding marks and left a much smoother surface. Profile and spacing checks proved that the overall gear tooth shape was not affected in any harmful way. Superfinishing uniformly removed approximately 2.5 microns from each surface.

  13. SPORTS ACTIVITIES SPONSORSHIP

    Directory of Open Access Journals (Sweden)

    DURBĂCEA - BOLOVAN MARIAN

    2016-12-01

    Full Text Available Sports and economy have discovered each other, hoping to serve common interests. In view of transferring in a more efficient way the information about their products or services to consumers, the business operator finances sports activities for advertising purposes. A company involved in sports sponsorship can instantly transmit the message about its products to millions of potential buyers, thus increasing the market share and hence the profit that it generates. By sponsoring sport it is meant any agreement / convention, under which one party the sponsor makes available to the beneficiary the material resources, financial and / or other benefits in exchange for its association with a sport or sportsman and especially the promise to use this association with sport or sportsman for the purpose of advertising, especially TV advertising. The growing use of athletes as spokespersons for a product is largely due to the ability of athletes to attract public attention and the credibility they enjoy

  14. Refleksiv Sports Management

    DEFF Research Database (Denmark)

    Adamsen, Billy

    2013-01-01

    Sports management and its development is closely linked to the development of modern society and modern rationality. This article applies sociological theories and practical management philosophy to shed light on how sports management and its rationality in Denmark (Europe) and the United States...... have changed and undergone different phases for more than a century, and to show that, in late modernity, they are entering a new phase in which they seem to be more reflexive and communicative. This trend is evident in American sports management and will also soon be reflected in Danish sports...... management. My analysis of this development will also be based on a specific case study from the American world of sports, namely the story of Oakland Athletics baseball club’s reorganisation in the 1990s, because it both provides a rare insight into a modern sports organisation and demonstrates...

  15. Ethics in sports medicine.

    Science.gov (United States)

    Dunn, Warren R; George, Michael S; Churchill, Larry; Spindler, Kurt P

    2007-05-01

    Physicians have struggled with the medical ramifications of athletic competition since ancient Greece, where rational medicine and organized athletics originated. Historically, the relationship between sport and medicine was adversarial because of conflicts between health and sport. However, modern sports medicine has emerged with the goal of improving performance and preventing injury, and the concept of the "team physician" has become an integral part of athletic culture. With this distinction come unique ethical challenges because the customary ethical norms for most forms of clinical practice, such as confidentiality and patient autonomy, cannot be translated easily into sports medicine. The particular areas of medical ethics that present unique challenges in sports medicine are informed consent, third parties, advertising, confidentiality, drug use, and innovative technology. Unfortunately, there is no widely accepted code of sports medicine ethics that adequately addresses these issues.

  16. MOTIVATION IN ADAPTED SPORT

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Torralba

    2014-05-01

    Full Text Available This study examines the motivation for practice of sport of people with disabilities that form part to a federated sport.The sample was composed of 134 athletes of both genders and different disabilities.The “Participation Motivation Inventory Questionnaire” by Gill, Gross and Huddleston was used. The instrument was adapted to Paralympic sport and describes the main reasons that encourage the sports activity practice. The results haven´t found significant difference between men´s and women´s or between blind - visually impaired physical and motor disabilities. About the motivation of the practice of sport, worth highlighting the importance given to factors of fitness and health, like sport practice, improve the level, to compete, feel good and have fun, well above being popular, influenced by coaches or satisfy to parents.

  17. Sport-related concussions

    Directory of Open Access Journals (Sweden)

    Jéssica Natuline Ianof

    Full Text Available ABSTRACT Traumatic brain injury (TBI is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such as American football, rugby, soccer, boxing, basketball and hockey are associated with a relatively high prevalence of concussion. Various factors may be associated with a greater risk of sport-related concussion, such as age, sex, sport played, level of sport played and equipment used. Physical complaints (headache, fatigue, dizziness, behavioral changes (depression, anxiety, irritability and cognitive impairment are very common after a concussion. The risk of premature return to activities includes the prolongation of post-concussive symptoms and increased risk of concussion recurrence.

  18. Refleksiv Sports Management

    DEFF Research Database (Denmark)

    Adamsen, Billy

    2013-01-01

    Sports management and its development is closely linked to the development of modern society and modern rationality. This article applies sociological theories and practical management philosophy to shed light on how sports management and its rationality in Denmark (Europe) and the United States...... have changed and undergone different phases for more than a century, and to show that, in late modernity, they are entering a new phase in which they seem to be more reflexive and communicative. This trend is evident in American sports management and will also soon be reflected in Danish sports...... management. My analysis of this development will also be based on a specific case study from the American world of sports, namely the story of Oakland Athletics baseball club’s reorganisation in the 1990s, because it both provides a rare insight into a modern sports organisation and demonstrates...

  19. STUDY ON THE LUBRICATION FACTOR OF INVOLUTE SPUR GEARS

    Institute of Scientific and Technical Information of China (English)

    Gao Chuangkuan; Qi Xiumei; Xiong Shibo

    2004-01-01

    Based on a lot of numerical solutions to the problems of the thermal non-Newtonian elastohydrodynamic lubrication and some fatigue tests with rollers, the lubrication factor of involute spur gears (called gear for short) is investigated. The results suggest that gear lubrication effects bear close relations to a dimensionless parameter D which is synthetically determined by gearing rotational speed, load, material, dimension and lubricant viscosity. When D≤8, the gear fatigue life increases as the lubricant viscosity is increased; When D>8, however, the life decreases with the viscosity addition, which is in marked contrast to the lubrication factor ZL recommended by the International Standard for Computing Cylindrical Gear Strength. At the end, a set of formulae for calculating gear lubrication factors suitable for different working conditions are advanced.

  20. Finite Element Residual Stress Analysis of Planetary Gear Tooth

    Directory of Open Access Journals (Sweden)

    Jungang Wang

    2013-01-01

    Full Text Available A method to simulate residual stress field of planetary gear is proposed. In this method, the finite element model of planetary gear is established and divided to tooth zone and profile zone, whose different temperature field is set. The gear's residual stress simulation is realized by the thermal compression stress generated by the temperature difference. Based on the simulation, the finite element model of planetary gear train is established, the dynamic meshing process is simulated, and influence of residual stress on equivalent stress of addendum, pitch circle, and dedendum of internal and external meshing planetary gear tooth profile is analyzed, according to non-linear contact theory, thermodynamic theory, and finite element theory. The results show that the equivalent stresses of planetary gear at both meshing and nonmeshing surface are significantly and differently reduced by residual stress. The study benefits fatigue cracking analysis and dynamic optimization design of planetary gear train.

  1. Investigation of Sideband Index Response to Prototype Gear Tooth Damage

    Science.gov (United States)

    Dempsey, Paula J.

    2013-01-01

    The objective of this analysis was to evaluate the ability of gear condition indicators (CI) to detect contact fatigue damage on spiral bevel gear teeth. Tests were performed in the NASA Glenn Spiral Bevel Gear Fatigue Rig on eight prototype gear sets (pinion/gear). Damage was initiated and progressed on the gear and pinion teeth. Vibration data was measured during damage progression at varying torque values while varying damage modes to the gear teeth were observed and documented with inspection photos. Sideband indexes (SI) and root mean square (RMS) CIs were calculated from the time synchronous averaged vibration data. Results found that both CIs respond differently to varying torque levels, damage levels and damage modes

  2. SYSTEMATIZATION OF SPORTS AND SPORT DISCIPLINES ACCORDING TO THE ASPECT OF SPORT TRAINING

    OpenAIRE

    Duško Bjelica

    2006-01-01

    According to the aspect of sport training, it's necessary to do the systematization of sports according to their content. The content of sports is presented by qualitative and quantitative structure of development, and the classification of sports is performed by the amount of participation of elementary bio-motor dimensions in sports, respectivly.

  3. Sports Specialization, Part II

    Science.gov (United States)

    Myer, Gregory D.; Jayanthi, Neeru; DiFiori, John P.; Faigenbaum, Avery D.; Kiefer, Adam W.; Logerstedt, David; Micheli, Lyle J.

    2016-01-01

    Context: Many coaches, parents, and children believe that the best way to develop elite athletes is for them to participate in only 1 sport from an early age and to play it year-round. However, emerging evidence to the contrary indicates that efforts to specialize in 1 sport may reduce opportunities for all children to participate in a diverse year-round sports season and can lead to lost development of lifetime sports skills. Early sports specialization may also reduce motor skill development and ongoing participation in games and sports as a lifestyle choice. The purpose of this review is to employ the current literature to provide evidence-based alternative strategies that may help to optimize opportunities for all aspiring young athletes to maximize their health, fitness, and sports performance. Evidence Acquisition: Nonsystematic review with critical appraisal of existing literature. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Based on the current evidence, parents and educators should help provide opportunities for free unstructured play to improve motor skill development and youth should be encouraged to participate in a variety of sports during their growing years to influence the development of diverse motor skills. For those children who do choose to specialize in a single sport, periods of intense training and specialized sport activities should be closely monitored for indicators of burnout, overuse injury, or potential decrements in performance due to overtraining. Last, the evidence indicates that all youth should be involved in periodized strength and conditioning (eg, integrative neuromuscular training) to help them prepare for the demands of competitive sport participation, and youth who specialize in a single sport should plan periods of isolated and focused integrative neuromuscular training to enhance diverse motor skill development and reduce injury risk factors. Strength of Recommendation Taxonomy (SORT): B. PMID

  4. Sport-related concussions

    OpenAIRE

    2014-01-01

    ABSTRACT Traumatic brain injury (TBI) is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such...

  5. SPORT MARKETING MIX STRATEGIES

    OpenAIRE

    Alexandru Lucian MIHAI

    2013-01-01

    This paper presents a brief overview of a significant element of the sport marketing management model called the marketing mix. The marketing mix is crucial because it defines the sport business, and much of the sport marketer’s time is spent on various functions within the marketing mix. The marketing mix is the strategic combination of the product, price, place and promotion elements. These elements are typically called the four Ps of marketing. Decisions and strategies for each are importa...

  6. Bevel gear driver and method having torque limit selection

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  7. Sports injuries Lesiones deportivas

    OpenAIRE

    2007-01-01

    Stress generated by sports practice has increased the probability that athletes suffer from acute and chronic injuries. Worldwide, there have been many different investigations concerning the incidence of sport injuries. The different ways in which results have been presented makes it difficult to compare among them. Rates of sports injuries vary between 1.7 and 53 per 1.000 hours of sports practice; 0.8 and 90.9 per 1.000 hours of training; 3.1 and 54.8 per 1.000 hours of competition, and 6....

  8. Confidentiality in Sports Medicine.

    Science.gov (United States)

    Malcolm, Dominic

    2016-04-01

    This article synthesizes existing literature to provide a summary of the ethical issues concerning patient confidentiality in sport. It outlines the medical principle of confidentiality and identifies cross-cultural ethicolegal variations that shape its implementation. Clinicians' multiple obligations, physical environments, and practice and policy contexts are discussed, and research detailing experiences of maintaining patient confidentiality in sport is reviewed. Policy recommendations for enhancing compliance with this ethical principle are summarized. It is argued that the context of sport exacerbates pressures on clinicians to break patient confidentiality, breaches occur regularly, and interventions are required to enhance ethical compliance in sports medicine. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Phospholipids and sports performance

    National Research Council Canada - National Science Library

    Jäger, Ralf; Purpura, Martin; Kingsley, Michael

    2007-01-01

    .... The participation in physical activity often challenges a variety of physiological systems; consequently, the ability to maintain normal cellular function during activity can determine sporting performance...

  10. Treating and Preventing Sports Hernias

    Science.gov (United States)

    ... Back to Healthy Living Treating and Preventing Sports Hernias If you play ice hockey, tennis or soccer, ... the most commonly misdiagnosed groin pain—a sports hernia. A sports hernia often results from overuse of ...

  11. On Sporting Nationalism : Research Methodology

    OpenAIRE

    Uchiumi, Kazuo

    2010-01-01

    There are some theories that with globalization nationalisms will disappear, but nationalisms have been growing more and more. In sport, the number of international sporting events is increasing and sporting nationalism is becoming more and more obvious. Recently sporting nationalism and its relationship with (political) nationalism has been focused on. In this paper the author analyzed sporting nationalism in Japan and compared it with that of the United Kingdom, where researches on sporting...

  12. Efficiency Formulas for the 2K-H Type Planetary Gear Train (A II Type Planetary Gear Train with an Idie Planet Pinion)

    OpenAIRE

    岸, 佐年; 両角, 宗晴

    1989-01-01

    A new 2K-H type planetary gear train with an idle planet pinion is devised. This planetary gear train consists of only spur gears. The function of this planetary gear train is equal to those of the internal 2K-H type planetary gear train and the bevel gear type planetary gear train. The efficiency formulas of this planetary gear train are derived from the theoretical analysis and tabulated. The formulas tabulated can be utilized safely without any understanding of the underlying theory.

  13. Marketing of sport tourism

    Directory of Open Access Journals (Sweden)

    A.S. Teletov

    2015-03-01

    Full Text Available The aim of the article. The aim of the article is to clarify the concept of «sport tourism marketing», to examine the state of its objects and to determine prospects for development of sport tourism in Ukraine. The paper singles out the role of sport in life; compares different types of cities in terms of provision the infrastructure for tourism development in the field of sports. Authors show the example of the campaign. The results of the analysis. The article deals with sport tourism as a form of total tourism conducted extensive research of sports tourism values compared between typical sports facilities and infrastructure of cities millionaires, large, medium and small Ukrainian cities. The research is based on Sumy. It is shown that it may be attractive for sports, historical and cultural enrichment of professional athletes, children and adolescents, a large group of fans that come to competition. Marketing approaches to the decision of sport tourism problems today represent the ocial, cultural, public and political phenomenon simultaneously and is by phenomenon object of special researches. This increase: shows of sports, attraction to it of children, quantity of the people life, conducting a healthy image, increase of a network sport structures, hotels and other tourist objects. Work is complete scientific and practical work, implemented commission on education, science, culture, tourism, sport and youth policy Sumy Regional Council and is recommended to be involved to realizing for local councils, administrations and City Hall for recovery work in the field of tourism development. The theoretical and methodological developments generalizations made in this scientific work, have a scientific value and practical value and can be recommended for implementation in other regions of Ukraine. Conclusions and prospects for further researches. One of the few areas that still have powerful sports, tourism and how their derivatives – marketing

  14. Tendinopathy in Sport

    Science.gov (United States)

    Ackermann, Paul W.; Renström, Per

    2012-01-01

    Context: Tendinopathy is increasing in prevalence and accounts for a substantial part of all sports injuries and occupational disorders. Despite the magnitude of the disorder, high-quality scientific data on etiology and available treatments have been limited. Evidence Acquisition: The authors conducted a MEDLINE search on tendinopathy, or “tendonitis” or “tendinosis” or “epicondylitis” or “jumpers knee” from 1980 to 2011. The emphasis was placed on updates on epidemiology, etiology, and recent patient-oriented Level 1 literature. Results: Repetitive exposure in combination with recently discovered intrinsic factors, such as genetic variants of matrix proteins, and metabolic disorders is a risk factor for the development of tendinopathy. Recent findings demonstrate that tendinosis is characterized by a fibrotic, failed healing response associated with pathological vessel and sensory nerve ingrowth. This aberrant sensory nerve sprouting may partly explain increased pain signaling and partly, by release of neuronal mediators, contribute to the fibrotic alterations observed in tendinopathy. The initial nonoperative treatment should involve eccentric exercise, which should be the cornerstone (basis) of treatment of tendinopathy. Eccentric training combined with extracorporeal shockwave treatment has in some reports shown higher success rates compared to any therapies alone. Injection therapies (cortisone, sclerosing agents, blood products including platelet-rich plasma) may have short-term effects but have no proven long-term treatment effects or meta-analyses to support them. For epicondylitis, cortisone injections have demonstrated poorer long-time results than conservative physiotherapy. Today surgery is less indicated because of successful conservative therapies. New minioperative procedures that, via the endoscope, remove pathologic tissue or abnormal neoinnervation demonstrate promising results but need confirmation by Level 1 studies. Conclusions

  15. Return to Sport After Shoulder Arthroplasty in Recreational Athletes: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Aim, Florence; Werthel, Jean-David; Deranlot, Julien; Vigan, Marie; Nourissat, Geoffroy

    2017-07-01

    One of the most frequent demands from patients after shoulder replacement surgery is to return to sport. To determine the rate of return to sport after shoulder arthroplasty (total shoulder arthroplasty, reverse shoulder arthroplasty, hemiarthroplasty) in recreational athletes. Meta-analysis and systematic review. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed to perform this systematic review and meta-analysis of the results in the literature as well as the presentation of results. A search of the literature was performed in the electronic databases MEDLINE, Scopus, Embase, and the Cochrane Library. The quality of the included studies was evaluated according to the MINORS (Methodological Index for Nonrandomized Studies) score. Inclusion criteria were studies in English evaluating return to sport after shoulder replacement surgery and on patients practicing a sport regularly, whatever the level, with all ages and sports included. The main criterion was the rate of patients who returned to a sport activity. Nine studies were selected among the 35 identified, including a total of 613 patients (39% male and 61% female) with a mean age of 71.7 years (range, 22.6-92.6 years). All the included patients practiced sports before surgery. The most common reported sports were golf (n = 140), swimming (n = 128), and tennis (n = 54). The mean rate of return to sport was 80.7% (range, 57.1%-97.3%). All patients who returned to sport were practicing in the 3 months before surgery. No radiological data were reported in the literature. The subgroup analysis for resuming golf after shoulder arthroplasty revealed a rate of return to sport of 79.2% (95% CI, 62.9%-89.5%). In the swimming subgroup, the rate was 75.6% (95% CI, 61.3%-85.8%) and in the tennis subgroup was 63.5% (95% CI, 34.1%-85.5%). The subgroup analysis for reverse shoulder arthroplasty reported a lower rate of return to sport than for all types of shoulder

  16. Engagement of Metal Debris into a Gear Mesh

    Science.gov (United States)

    Handschuh, Robert F.; Krantz, Timothy L.

    2009-01-01

    A series of bench top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock, and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined. INTRODUCTION In some space mechanisms the loading can be so high that there is some possibility that a gear chip might be liberated while in operation of the mechanism [1-5]. Also, due to the closely packed nature of some space mechanisms and the fact that a space grease is used for lubrication, chips that are released can then be introduced to other gear meshes within this mechanism. In this instance, it is desirable to know the consequences of a gear chip entering in between meshing gear teeth. To help provide some understanding, a series of bench-top experiments was conducted to engage chips of simulated and gear material fragments into a meshing gear pair. One purpose of the experiments was to determine the relationship of chip size to the torque required to rotate the gear set through the mesh cycle. The second purpose was to determine the condition of the gear chip material after engagement by the meshing gears, primarily to determine if the chip would break into pieces and to observe the motion of the chip as the engagement was completed. This document also presents preliminary testing done with metal debris other than chips from gears, namely steel shim stock and drill bits of various sizes and diameters.

  17. Sports Hernia (Athletic Pubalgia)

    Science.gov (United States)

    ... a traditional, abdominal hernia, it is a different injury. A sports hernia is a strain or tear of any ... to you about your symptoms and how the injury occurred. If you have a sports hernia, when your doctor does a physical examination, ...

  18. Sports-related concussions.

    Science.gov (United States)

    Conder, Robert L; Conder, Alanna A

    2015-04-01

    Concussions are an inherent part of collision sports such as football and soccer. As a subset of traumatic brain injury, concussions are neurometabolic events that cause transient neurologic dysfunction. Following a concussion, some athletes require longer neurologic recovery than others. Education and intervention aimed at prevention and management can minimize the long-term sequelae of sports-related concussions.

  19. Somatotypes in Sport

    Directory of Open Access Journals (Sweden)

    Tóth Teodor

    2014-03-01

    Full Text Available The submitted article deals with the evaluation of the somatotype of persons and determination of a suitable somatotype for selected sports. In the introduction the method for determining and evaluating a somatotype according to Carter and Heath is characterised. The processes used for calculating the individual components - endomorphy, mesomorphy, ectomorphy - are presented as well as a description of these elements. The calculated components are subsequently put into a somatograph. The evaluation of a somatotype is of great benefit and offers a guideline with the selection of sporting activities; it subsequently helps assign athletes into a suitable position where they will be able to best develop their talents in view of their bodily construction. In this work two types of sports are evaluated - basketball and bodybuilding. With each sport the measurements which give the prerequisites for the given sport are presented. The selection of the presented sports was made with regard to the different requirements and demands in the scope of bodily constitution. The aim of the presented paper is to assess physical parameters of subjects groups in relation to selected sports (basketball and bodybuilding. Based on the body constitution to determine the conditions for developing the physical condition and success in the appointed sports. Another objective is to compare the rating form and equation methods for somatotype determination. The sample consist 32 subjects with age between 22-28 years of both sexes, who are dedicated to basketball, or bodybuilding at amateur level.

  20. Saga of American Sport.

    Science.gov (United States)

    Lucas, John A.; Smith, Ronald A.

    This history of sports and athletic activities in America covers a time span from the close of the sixteenth century to the present time. It is divided into three major sections. The first, "Colonial and Early American Sport," narrates the early moral and ethical attitudes of the Puritans and follows the changes in attitudes and introduction of…

  1. Subarachnoid Haemorrhage and Sports

    Directory of Open Access Journals (Sweden)

    Liliana Sousa Nanji

    2015-11-01

    Full Text Available Background: Some cases of subarachnoid haemorrhage (SAH have been associated with vigorous physical activity, including sports. Our research aimed to describe the association between SAH and sports and to identify the types of sports that were more frequently found as precipitating factors in a tertiary single-centre SAH register. Methods: We retrieved information from a prospectively collected SAH registry and reviewed discharge notes of acute SAH patients admitted to the Stroke Unit of Hospital de Santa Maria, Lisbon, between 1995 and 2014. Results: Out of 738 patients included in the analysis, 424 (57.5% cases of SAH were preceded by physical activity. Nine cases (1.2% were associated with sports, namely running (2 cases, aerobics (2 cases, cycling, body balance, dance, surf and windsurf. Patients with SAH while practicing sports were younger than controls (average age 43.1 vs. 57.0 years; p = 0.007. In 1 patient, there was a report of trauma to the neck. Patients in the sports group only had Hunt and Hess scale grades 1 (11.1% or 2 (88.9% at admission, while patients in the control group had a wider distribution in severity. Conclusions: Our findings indicate that SAH precipitated by sports is not very frequent and is uncommonly related to trauma. Patients who suffered SAH associated with sports were younger and apparently had a milder clinical presentation.

  2. A Rising Sport

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Tennis is becoming more popular in China but there are still worries facing the sport 0ctober was a happy time for the sport of tennis and tennis fans in China. The China Open in Beijing,the 2010 Shanghai Rolex Masters and the China Tennis Grand Prix in Nanjing,Jiangsu Province,all take place.

  3. Mathematics and Sports

    Science.gov (United States)

    Gallian, Joseph A., Ed.

    2010-01-01

    "Mathematics and Sports", edited by Joseph A. Gallian, gathers 25 articles that illuminate the power and role of mathematics in the worlds of professional and recreational play. Divided into sections by the kind of sports, the book offers source materials for classroom use and student projects. Readers will encounter mathematical ideas from an…

  4. Youth Sports Safety Statistics

    Science.gov (United States)

    ... sb75.pdf. 3 Centers for Disease Control and Prevention. Sports-related injuries among high school athletes, United States, 2005-06 ... 495-503. 10 Centers for Disease Control and Prevention. Nonfatal traumatic brain injuries related to sports and recreation activities among persons aged ≤19 years— ...

  5. Dealing with Sports Injuries

    Science.gov (United States)

    ... Print A A A What's in this article? Prevention First Types of Sports Injuries What To Do Where Injuries Happen Getting Back ... Game en español Cómo afrontar las lesiones deportivas Prevention First The best way to deal with sports injuries is to keep them from happening in the ...

  6. NOTATIONAL ANALYSIS OF SPORT

    Directory of Open Access Journals (Sweden)

    Ian M. Franks

    2004-06-01

    Full Text Available This book addresses and appropriately explains the notational analysis of technique, tactics, individual athlete/team exercise and work-rate in sport. The book offers guidance in: developing a system, analyzes of data, effective coaching using notational performance analysis and modeling sport behaviors. It updates and improves the 1997 edition

  7. Superstition in Sport.

    Science.gov (United States)

    Gregory, C. Jane; Petrie, Brian M.

    The introduction of this investigation into superstitions of athletes reviews past research on the subject. It is stated, though, that general research on superstitions mentions little directly related to sports; so, by necessity, recourse is made to sports stories and newspaper and magazine articles. The main body of this paper presents results…

  8. Sports and Concussions

    Science.gov (United States)

    ... teams, you probably know that concussions are a serious issue. Playing sports increases a person's risk of falls and collisions ... it might happen on the sidelines during a game. Sideline testing is common in schools and sports leagues. By watching you and doing a few ...

  9. Sport as Yoga

    Science.gov (United States)

    Murphy, Michael

    1977-01-01

    The author has written a metaphysical sports fantasy and completed a novel which explores evolutionary transformations of the mind and body. Now he is working on a long-term research project exploring radical bodily transformations occurring in various fields of human experience. This article on sport is part of that project. (Editor/RK)

  10. Three-Dimensional Gear Crack Propagation Studied

    Science.gov (United States)

    Lewicki, David G.

    1999-01-01

    Gears used in current helicopters and turboprops are designed for light weight, high margins of safety, and high reliability. However, unexpected gear failures may occur even with adequate tooth design. To design an extremely safe system, the designer must ask and address the question, "What happens when a failure occurs?" With gear-tooth bending fatigue, tooth or rim fractures may occur. A crack that propagates through a rim will be catastrophic, leading to disengagement of the rotor or propeller, loss of an aircraft, and possible fatalities. This failure mode should be avoided. A crack that propagates through a tooth may or may not be catastrophic, depending on the design and operating conditions. Also, early warning of this failure mode may be possible because of advances in modern diagnostic systems. One concept proposed to address bending fatigue fracture from a safety aspect is a splittooth gear design. The prime objective of this design would be to control crack propagation in a desired direction such that at least half of the tooth would remain operational should a bending failure occur. A study at the NASA Lewis Research Center analytically validated the crack-propagation failsafe characteristics of a split-tooth gear. It used a specially developed three-dimensional crack analysis program that was based on boundary element modeling and principles of linear elastic fracture mechanics. Crack shapes as well as the crack-propagation life were predicted on the basis of the calculated stress intensity factors, mixed-mode crack-propagation trajectory theories, and fatigue crack-growth theories. The preceding figures show the effect of the location of initial cracks on crack propagation. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth was simulated in a case study to evaluate crack-propagation paths. Tooth

  11. Gear Windage Modeling Progress - Experimental Validation Status

    Science.gov (United States)

    Kunz, Rob; Handschuh, Robert F.

    2008-01-01

    In the Subsonics Rotary Wing (SRW) Project being funded for propulsion work at NASA Glenn Research Center, performance of the propulsion system is of high importance. In current rotorcraft drive systems many gearing components operate at high rotational speed (pitch line velocity > 24000 ft/ min). In our testing of high speed helical gear trains at NASA Glenn we have found that the work done on the air - oil mist within the gearbox can become a significant part of the power loss of the system. This loss mechanism is referred to as windage. The effort described in this presentation is to try to understand the variables that affect windage, develop a good experimental data base to validate, the analytical project being conducted at Penn State University by Dr. Rob Kunz under a NASA SRW NRA. The presentation provides an update to the status of these efforts.

  12. Geared Topological Metamaterials with Tunable Mechanical Stability

    Science.gov (United States)

    Meeussen, Anne S.; Paulose, Jayson; Vitelli, Vincenzo

    2016-10-01

    The classification of materials into insulators and conductors has been shaken up by the discovery of topological insulators that conduct robustly at the edge but not in the bulk. In mechanics, designating a material as insulating or conducting amounts to asking if it is rigid or floppy. Although mechanical structures that display topological floppy modes have been proposed, they are all vulnerable to global collapse. Here, we design and build mechanical metamaterials that are stable and yet capable of harboring protected edge and bulk modes, analogous to those in electronic topological insulators and Weyl semimetals. To do so, we exploit gear assemblies that, unlike point masses connected by springs, incorporate both translational and rotational degrees of freedom. Global structural stability is achieved by eliminating geometrical frustration of collective gear rotations extending through the assembly. The topological robustness of the mechanical modes makes them appealing across scales from engineered macrostructures to networks of toothed microrotors of potential use in micromachines.

  13. Flex-gear electrical power transmission

    Science.gov (United States)

    Vranish, John; Peritt, Jonathan

    1993-01-01

    This study was conducted to develop an alternative way of transferring electricity across a continuously rotating joint, with little wear and the potential for low electrical noise. The problems with wires, slip rings, electromagnetic couplings, and recently invented roll-rings are discussed. Flex-gears, an improvement of roll-rings, are described. An entire class of flexgear devices is developed. Finally, the preferred flex-gear device is optimized for maximum electrical contact and analyzed for average mechanical power loss and maximum stress. For a device diameter of six inches, the preferred device is predicted to have a total electrical contact area of 0.066 square inches. In the preferred device, a small amount of internal sliding produces a 0.003 inch-pound torque that resists the motion of the device.

  14. Geared Topological Metamaterials with Tunable Mechanical Stability

    Directory of Open Access Journals (Sweden)

    Anne S. Meeussen

    2016-11-01

    Full Text Available The classification of materials into insulators and conductors has been shaken up by the discovery of topological insulators that conduct robustly at the edge but not in the bulk. In mechanics, designating a material as insulating or conducting amounts to asking if it is rigid or floppy. Although mechanical structures that display topological floppy modes have been proposed, they are all vulnerable to global collapse. Here, we design and build mechanical metamaterials that are stable and yet capable of harboring protected edge and bulk modes, analogous to those in electronic topological insulators and Weyl semimetals. To do so, we exploit gear assemblies that, unlike point masses connected by springs, incorporate both translational and rotational degrees of freedom. Global structural stability is achieved by eliminating geometrical frustration of collective gear rotations extending through the assembly. The topological robustness of the mechanical modes makes them appealing across scales from engineered macrostructures to networks of toothed microrotors of potential use in micromachines.

  15. Global Analysis of a Planetary Gear Train

    Directory of Open Access Journals (Sweden)

    Tongjie Li

    2014-01-01

    Full Text Available By using the Poincaré-like cell-to-cell mapping method and shooting method, the global characteristics of a planetary gear train are studied based on the torsional vibration model with errors of transmission, time-varying meshing stiffness, and multiple gear backlashes. The study results reveal that the planetary with a certain set of parameters has four coexisting periodic orbits, which are P-1, P-2, P-4, and P-8, respectively. P-1 and P-2 motions are not of long-term stability, P-8 motion is of local stability, and P-4 motion is of global stability. Shooting method does not have the capacity of searching coexisting periodic orbits in a global scope, and it is easy to omit some periodic orbits which are far away from the main gropes of periodic orbits.

  16. Elastodynamic analysis of a gear pump. Part I: Pressure distribution and gear eccentricity

    Science.gov (United States)

    Mucchi, E.; Dalpiaz, G.; Fernàndez del Rincòn, A.

    2010-10-01

    A non-linear lumped kineto-elastodynamic model for the prediction of the dynamic behaviour of external gear pumps is presented. It takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. Fluid pressure distribution on gears, which is time-varying, is computed and included as a resultant external force and torque acting on the gears. Parametric excitations due to time-varying meshing stiffness, the tooth profile errors (obtained by a metrological analysis), the backlash effects between meshing teeth, the lubricant squeeze and the possibility of tooth contact on both lines of action were also included. Finally, the torsional stiffness and damping of the driving shaft and the non-linear behaviour of the hydrodynamic journal bearings were also taken into account. Model validation was carried out on the basis of experimental data concerning case accelerations and force reactions. The model can be used in order to analyse the pump dynamic behaviour and to identify the effects of modifications in design and operation parameters, in terms of vibration and dynamic forces. Part I is devoted to the calculation of the gear eccentricity in the steady-state condition as a result of the balancing between mean pressure loads, mean meshing force and bearing reactions, while in Part II the meshing phenomena are fully explained and the main simulation results are presented.

  17. Coatings for gear wheels; Beschichtungen fuer Zahnraeder

    Energy Technology Data Exchange (ETDEWEB)

    Petrik, M.; Wittorf, R.; Thomsen, H. [Fraunhofer-Institut fuer Schicht- und Oberflaechentechnik, IST, Braunschweig (Germany). Transferzentrum Tribologie; Kaestner, P. [Technische Univ. Braunschweig (Germany). Inst. fuer Oberflaechentechnik; Kropp, J.P. [Technische Univ. Braunschweig (Germany). Inst. fuer Konstruktionstechnik

    2008-08-15

    In order to optimize the goal, steel gear wheels regarding load-carrying capacity and wear, thin film coatings were tested. Different coating systems were examined numerically with the software ELASTICA {sup registered} for their suitability. The characteristics of the coating systems were determined dependent on the material, its surface treatment as well as the diameters of relevant rolling partners. Differences were made between macroscopic rolling contacts between the teeth profiles and microscopic contacts with surface roughness and abrasion particles. First the four best suitable coating systems were deposited on simplified rollers and examined under different conditions. Two coating systems were determined, which show special suitability for the coating of the gear wheels. The first system is an a:C-H coating with an CrN interlayer. The second system is an a:C-H coating with an CrN interlayer on a plasma-nitrided substrat (Duplex-process). In order to protect the coatings on the teeth, their involute profile was provided with a tip relief. As gear wheel materials 16MnCr5, 42CrMo4 as well as the special steel ETG {sup registered} 88 were used. Two kinds of flow fats were used as lubricants and additional the unlubricated operation was examined. The gear wheels were tested at three different speeds on a test machine especially built for it. The testing routine was carried out in so-called power-stages. Each stage means a defined number of contacts and a certain Hertzian stress on the teeth profiles. With each stage the Hertzian stress was increased. The end of operation time is the beginning of cavitation pitting. The test results showed that in particular with the steel 16MnCr5 and 42CrMo4 the used Duplex-systems leads to considerable increases of the load-carrying capacity of the tooth flanks and the wear resistance. (orig.)

  18. Design Optimization of Marine Reduction Gears.

    Science.gov (United States)

    1983-09-01

    Approved by: A t/ 6 𔃼 -A-,i Thesis Advisor Second Reader Chairman,De rtment or Mecanica Engineering I De&n of Science and Engineering 3...unconstrained problems. 1. Direct Methods Direct methods are popular constrained optimization algorithms. One well known direct method is the method of...various popular tooth forms and Appendix A contains a descriptive figure of gear tooth design variables. However, the following equations are a good

  19. Policy, Sport and Integration

    DEFF Research Database (Denmark)

    Agergaard, Sine; Sørensen, Jan Kahr

    2010-01-01

    Increased public funding, more governmental involvement and an emphasis on the instrumental values of physical activities have in general become characteristic of Western nations’ policies towards sport. Denmark is, however, a little different in that there is still little political intervention...... in sport, although sports clubs do get economic support and are seen as having the potential to solve crucial social issues. The purpose of this article is to analyse and discuss the ways in which the political assumption that sport can enhance social integration is reflected in the practical governance...... of integration issues in particular in sports clubs. The article is based on a local field study in which we interviewed 10 talented football players with ethnic minority backgrounds and eight coaches and club leaders from six different football clubs. Distinguishing between integration and assimilation...

  20. [Arrhythmia and sport].

    Science.gov (United States)

    Saoudi, N; Yaici, K; Zarkane, N; Darmon, J P; Rinaldi, J P; Brunner, P; Ricard, P; Mourou, M Y

    2005-12-01

    Sports arrhythmia has gained wide attention with the mediatization of the death of famous sports stars. Sport strongly modifies the structure of the heart with the development of left ventricular hypertrophy which may be difficult to differentiate from that due to doping. Intense training modifies also the resting electrocardiogram with appearance of signs of left ventricular hypertrophy whereas resting sinus bradycardia and atrioventricular conduction disturbances usually reverts upon exertion. Accordingly, arrhythmia may develop ranging from extrasystoles to atrial fibrillation and even sudden death. Recent data suggest that if benign arrhythmia may be the result of the sole intense training and are reversible, malignant ventricular arrhythmia and sudden death mostly occur in unknown structural heart disease. Hypertrophic cardiomyopathy is amongst the most frequent post mortem diagnosis in this situation. Doping is now present in many sports and further threatens the athlete in the safe practice of sport.

  1. MINDFULNESS AND SPORT PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Israel Mañas

    2014-05-01

    Full Text Available Mindfulness in sports is a recent field. While sport psychology relied mainly on “second wave” cognitive-behavioural interventions for the last four decades, a new approach has recently been developed in sport psychology including mindfulness: a “third wave” approach. This new approach assumes that ideal performance is a state that is not based on self-control or change in behaviour, but rather a state that arises from recognition and acceptance of thoughts, emotions and bodily sensations. Practicing mindfulness allows learns to observe and accept the thoughts, emotions, and body sensations, without making any attempt to eliminate or modify them. This paper reviews the main programs of mindfulness in sport performance both from the “third wave”: Mindful Sport Performance Enhancement (MSPE and Mindfulness-Acceptance-Commitment(MAC.

  2. Overview of sports vision

    Science.gov (United States)

    Moore, Linda A.; Ferreira, Jannie T.

    2003-03-01

    Sports vision encompasses the visual assessment and provision of sports-specific visual performance enhancement and ocular protection for athletes of all ages, genders and levels of participation. In recent years, sports vision has been identified as one of the key performance indicators in sport. It is built on four main cornerstones: corrective eyewear, protective eyewear, visual skills enhancement and performance enhancement. Although clinically well established in the US, it is still a relatively new area of optometric specialisation elsewhere in the world and is gaining increasing popularity with eyecare practitioners and researchers. This research is often multi-disciplinary and involves input from a variety of subject disciplines, mainly those of optometry, medicine, physiology, psychology, physics, chemistry, computer science and engineering. Collaborative research projects are currently underway between staff of the Schools of Physics and Computing (DIT) and the Academy of Sports Vision (RAU).

  3. Sports: The Infectious Hazards.

    Science.gov (United States)

    Minooee, Arezou; Wang, Jeff; Gupta, Geeta K

    2015-10-01

    Although the medical complications of sports are usually traumatic in nature, infectious hazards also arise. While blood-borne pathogens such as HIV, hepatitis B, and hepatitis C, cause significant illness, the risk of acquiring these agents during sporting activities is minimal. Skin infections are more commonplace, arising from a variety of microbial agents including bacterial, fungal, and viral pathogens. Sports involving water contact can lead to enteric infections, eye infections, or disseminated infections such as leptospirosis. Mumps, measles, and influenza are vaccine-preventable diseases that have been transmitted during sporting events, both in players and in spectators. Prevention is the key to many of these infections. Players should be vaccinated and should not participate in sports if their infection can be spread by contact, airborne, or droplet transmission.

  4. X-38 Landing Gear qualification testing

    Science.gov (United States)

    Urgoiti, Eduardo

    2003-09-01

    The Landing Gear System for the X-38 demonstration vehicle has been developed considering future application to the CRV vehicle. It consists of three legs in a typical aeroplane configuration with two main and one nose legs. They are retracted during ascent, in orbit and re-entry phases and are released near the ground by pyrotechnic-nuts and deployed by preloaded springs and gravity. This gear has been designed to allow landing in unprepared plain fields limiting the accelerations on the spacecraft at touch down, through expendable damping cartridges and skids. During 2002 the test campaign of the X-38 Landing Gear has been completed at Sener. Three different types of tests have been performed: Functional deployment tests, Static load tests and vibration tests. This paper discusses the objectives of the tests and how they are achieved with a description of the mechanisms involved and their predicted performances. The different types of tests and results are described together with the major events and lessons learned during their performance.

  5. EPIDEMIOLOGY OF PEDIATRIC SPORTS INJURIES: INDIVIDUAL SPORTS

    Directory of Open Access Journals (Sweden)

    Dennis J. Caine

    2005-06-01

    Full Text Available The objective of the book is to review comprehensively what is known about the distribution and determinants of injury rates in a variety of individual sports, and to suggest injury prevention measures and guidelines for further research. This book provides comprehensive compilation and critical analysis of epidemiological data over children's individual sports: including equestrian, gymnastics, martial arts, skiing and snowboarding, tennis, track and field, and wrestling. This book encourages coaches and sports administrators to discuss rules, equipment standards, techniques, and athlete conditioning programs. In turn, they can inform parents about the risks and how they can help their children avoid or limit injury in sports. A common, uniform strategy and evidence-based approach to organizing and interpreting the literature is used in all chapters. All the sports-specific chapters are laid out with the same basic headings, so that it is easy for the reader to find common information across chapters. Chapter headings are: 1 Epidemiology of children's individual sports injuries, 2 Equestrian injuries, 2 Gymnastics injuries, 3 Martial arts injuries, 4 Skiing and snowboard injuries, 5 Tennis injuries, 6 Track and field injuries, 7 Wrestling injuries, 8 Injury prevention and future research. Chapter headings include: i Incidence of injury, ii Injury characteristics, iii Injury severity, iv njury risk factors, v Suggestions for injury prevention, vi Suggestions for further research. In each sports-specific chapter, an epidemiological picture has been systematically developed from the data available in prospective cohort, retrospective cohort, case-control, and cross-sectional studies. The tables are numerous, helpful and very useful. The book provides a very useful resource for sport scientist, pediatricians, family practitioners and healthcare professionals in the field of child and adolescent injury and prevention The readers are going to

  6. 78 FR 68817 - Proposed Information Collection; Comment Request; Northeast Region Gear Identification

    Science.gov (United States)

    2013-11-15

    ... Region Gear Identification AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and.... Abstract This notice is for the extension of Paperwork Reduction Act requirements regarding fishing gear... fishing gear mark the gear with specified information. The gear marking requirements provide vessel...

  7. Face Gear Technology for Aerospace Power Transmission Progresses

    Science.gov (United States)

    2005-01-01

    The use of face gears in an advanced rotorcraft transmission design was first proposed by the McDonnell Douglas Helicopter Company during their contracted effort with the U.S. Army under the Advanced Rotorcraft Transmission (ART) program. Face gears would be used to turn the corner between the horizontal gas turbine engine and the vertical output rotor shaft--a function currently done by spiral bevel gears. This novel gearing arrangement would substantially lower the drive system weight partly because a face gear mesh would be used to split the input power between two output gears. However, the use of face gears and their ability to operate successfully at the speeds and loads required for an aerospace environment was unknown. Therefore a proof-of-concept phase with an existing test stand at the NASA Lewis Research Center was pursued. Hardware was designed that could be tested in Lewis' Spiral Bevel Gear Test Rig. The initial testing indicated that the face gear mesh was a feasible design that could be used at high speeds and load. Surface pitting fatigue was the typical failure mode, and that could lead to tooth fracture. An interim project was conducted to see if slight modifications to the gear tooth geometry or an alternative heat treating process could overcome the surface fatigue problems. From the initial and interim tests, it was apparent that for the surface fatigue problems to be overcome the manufacturing process used for this component would have to be developed to the level used for spiral bevel gears. The current state of the art for face gear manufacturing required using less than optimal gear materials and manufacturing techniques because the surface of the tooth form does not receive final finishing after heat treatment as it does for spiral bevel gears. This resulted in less than desirable surface hardness and manufacturing tolerances. An Advanced Research and Projects Agency (ARPA) Technology Reinvestment Project has been funded to investigate

  8. Some Sports Managers' Views about Values Education through Sports

    Science.gov (United States)

    Balci, Velittin; Erdeveciler, Övünç

    2017-01-01

    The indirect aim of this study is to ensure that sports and participation in sports are seen as new tools for values education. From this indirect goal, it was aimed to analyse the views of some Amateur Sports Club managers and supporters who were supposed to directly contribute to sports and the athletes about values education. The study was…

  9. Developing Sport Psychology in a Girls' Sport Academy Curriculum

    Science.gov (United States)

    Lewis, Andrew

    2014-01-01

    This article explores the initial steps in developing and presenting Sport Psychology in a leadership and sport curriculum at Stellenbosch University's (SU) Centre for Human Performance Sciences' (CHPS) Academy for Girls' Leadership and Sport Development. Sport Psychology does not feature within the South African school curriculum specifically,…

  10. Određivanje krutosti planetarnog prenosnika / Determination of gear mesh stiffness in planetary gearing

    Directory of Open Access Journals (Sweden)

    Vojislav Batinić

    2008-04-01

    Full Text Available Kontaktna krutost zubaca jedan je od glavnih generatora unutrašnjih dinamičkih sila u spregama zupčanika planetarnih prenosnika. Neophodan je pri opisivanju dinamičkog ponašanja planetarnih prenosnika, tj. pri postavljanju jednačina dinamičke ravnoteže. U radu je prikazan metodološki pristup analitičkom i eksperimentalnom određivanju krutosti posmatranog planetarnog prenosnika. / Gear mesh stiffness in planetary gearing is one of the main generators of internal dynamic forces. It is necessary in describing dynamic behavior of planetary trains, i.e. in defining their equations of dynamic balance. This paper presents a methodological approach to experimental and analytical calculation of stiffness in planetary gearing.

  11. Displaceable spur gear torque controlled driver and method

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

  12. Bifurcation phenomena in internal dynamics of gear systems

    Directory of Open Access Journals (Sweden)

    Hortel M.

    2007-10-01

    Full Text Available The impact effects in gear mesh represent specific phenomena in the dynamic investigation of highspeed light transmission systems with kinematic couplings. They are caused of greater dynamic than static elastic deformations in meshing gear profiles. In term of internal dynamics they are influenced among others by time heteronomous stiffness functions in gear mesh and resonance tuning of stiffness level. The damping in gear mesh and in gear system is concerned significantly in the amplitude progress, greatness and phase shift of relative motion towards stiffness function alternatively towards its modify form in gear mesh. In consequence of these and another actions rise above resonance characteristics certain singular locations with jump amplitude course.

  13. Prediction of potential failures in hydraulic gear pumps

    Directory of Open Access Journals (Sweden)

    E. Lisowski

    2010-07-01

    Full Text Available Hydraulic gear pumps are used in many machines and devices. In hydraulic systems of machines gear pumps are main component ofsupply unit or perform auxiliary function. Gear pumps opposite to vane pumps are less complicated. They consists of such components as:housing, gear wheels, bearings, shaft, seal for rotation motion which are not very sensitive for damage and that is why they are using veryoften. However, gear pumps are break down from time to time. Usually damage of pump cause shutting down of machines and devices.One of the way for identifying potential failures and foreseeing their effects is a quality method. On the basis of these methods apreventing action might be undertaken before failure appear. In this paper potential failures and damages of a gear pump were presented bythe usage of matrix FMEA analysis.

  14. The generalized transmission error of spiral bevel gears

    Science.gov (United States)

    Mark, W. D.

    1987-01-01

    The traditional definition of the transmission error of parallel-axis gear pairs is reviewed and shown to be unsuitable for characterizing the deviation from conjugate action of bevel gear pairs for vibration excitation characterization purposes. This situation is rectified by generalizing the concept of the transmission error of parallel-axis gears to a three-component transmission error for spiral bevel gears of nominal spherical involute design. A general relationship is derived which expresses the contributions to the three-component transmission error from each gear of a meshing spiral bevel pair as a linear transformation of the six coordinates that describe the deviation of the shaft centerline position of each gear of the pair from the position of its rigid perfect involute counterpart.

  15. Using hob offset to balance dynamic strength in spur gears

    Science.gov (United States)

    Liou, Chuen-Huei; Lin, Hsi Hsiang; Oswald, Fred B.; Townsend, Dennis P.

    1995-05-01

    This paper presents an analytical study on the effect of hob offset on the dynamic tooth strength of spur gears. The study was limited to equal and opposite offset values applied to the pinion and gear to maintain the standard operating center distance. The analysis presented in this paper was performed using a new version of the NASA gear dynamics code DANST. The operating speed of the transmission has a significant influence on the amount of hob offset required to equalize the dynamic stresses in the pinion and gear. In the transmission studied, at low speeds, the optimum hob offset value was found to fluctuate. At higher speeds, the optimum value was constrained by the minimum allowed thickness at the tip of the pinion tooth. For gears that must operate over a range of speeds, an average offset value may be used. Spur gears designed with the procedure presented here can have significant improvements in load capacity.

  16. Interactions between nonlinear spur gear dynamics and surface wear

    Science.gov (United States)

    Ding, Huali; Kahraman, Ahmet

    2007-11-01

    In this study, two different dynamic models, a finite elements-based deformable-body model and a simplified discrete model, and a surface wear model are combined to study the interaction between gear surface wear and gear dynamic response. The proposed dynamic gear wear model includes the influence of worn surface profiles on dynamic tooth forces and transmission error as well as the influence of dynamic tooth forces on wear profiles. This paper first introduces the nonlinear dynamic models that include gear backlash and time-varying gear mesh stiffness, and a wear model separately. It presents a comparison to experiments for validation of the dynamic models. The dynamic models are combined with the wear model to study the interaction of surface wear and dynamic behavior in both linear and nonlinear response regimes. At the end, several sets of simulation results are used to demonstrate the two-way relationship between nonlinear gear dynamics and surface wear.

  17. Utilization of radiation protection gear for absorbed dose reduction: an integrative literature review

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Flor, Rita de Cassia [Instituto Federal de Santa Catarina (IFSC), Florianopolis, SC (Brazil); Pereira, Aline Garcia, E-mail: aalinegp@gmail.co [Sinan Project - Sistema de Informacao de Agravos de Notificacao, Florianopolis, SC (Brazil)

    2011-03-15

    Objective: The present study was aimed at evaluating the relation between the use of radiation protection gear and the decrease in absorbed dose of ionizing radiation, thereby reinforcing the efficacy of its use by both the patients and occupationally exposed personnel. Materials and Methods: The integrative literature review method was utilized to analyze 21 articles, 2 books, 1 thesis, 1 monograph, 1 computer program, 4 pieces of database research (Instituto Brasileiro de Geografia e Estatistica and Departamento de Informatica do Sistema Unico de Saude) and 2 sets of radiological protection guidelines. Results: Theoretically, a reduction of 86% to 99% in the absorbed dose is observed with the use of radiation protection gear. In practice, however, the reduction may achieve 88% in patients submitted to conventional radiology, and 95% in patients submitted to computed tomography. In occupationally exposed individuals, the reduction is around 90% during cardiac catheterization, and 75% during orthopedic surgery. Conclusion: According to findings of several previous pieces of research, the use of radiation protection gear is a low-cost and effective way to reduce absorbed dose both for patients and occupationally exposed individuals. Thus, its use is necessary for the implementation of effective radioprotection programs in radiodiagnosis centers. (author)

  18. Infusing Disability Sport into the Sport Management Curriculum

    Directory of Open Access Journals (Sweden)

    Jimmy Calloway

    2012-01-01

    Full Text Available Disability sport is growing around the world with momentum and is described as a “movement” (Bailey, 2008; DePauw & Gavron, 2005. While there are more similarities than differences with sport management for able-bodied athletes and those with disabilities, there are additional needs and considerations for persons with disabilities (DePauw & Gavron, 2005. The noticeable visibility of individuals with disabilities in society, including sport, raises concerns about the degree to which sport management academic programs have modified their curricula to ensure that individuals working in the sport management field are prepared to deal with theuniqueness of disability sport. This paper (a discusses theoretical perspectives toward understanding and thinking about disability, (b explores ways to enhance sport management curricula through infusion of disability sport, (c reflects upon current social practices for curriculum integration of athletes with disabilities in sport, and (d acknowledges infusion of disability sport businesses, organizations and events.

  19. DESIGN IMPROVEMENT OF THE LOCOMOTIVE RUNNING GEARS

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2013-09-01

    Full Text Available Purpose. To determine the dynamic qualities of the mainline freight locomotives characterizing the safe motion in tangent and curved track sections at all operational speeds, one needs a whole set of studies, which includes a selection of the design scheme, development of the corresponding mathematical model of the locomotive spatial fluctuations, construction of the computer calculation program, conducting of the theoretical and then experimental studies of the new designs. In this case, one should compare the results with existing designs. One of the necessary conditions for the qualitative improvement of the traction rolling stock is to define the parameters of its running gears. Among the issues related to this problem, an important place is occupied by the task of determining the locomotive dynamic properties on the stage of projection, taking into account the selected technical solutions in the running gear design. Methodology. The mathematical modeling studies are carried out by the numerical integration method of the dynamic loading for the mainline locomotive using the software package «Dynamics of Rail Vehicles » («DYNRAIL». Findings. As a result of research for the improvement of locomotive running gear design it can be seen that the creation of the modern locomotive requires from engineers and scientists the realization of scientific and technical solutions. The solutions enhancing design speed with simultaneous improvement of the traction, braking and dynamic qualities to provide a simple and reliable design, especially the running gear, reducing the costs for maintenance and repair, low initial cost and operating costs for the whole service life, high traction force when starting, which is as close as possible to the ultimate force of adhesion, the ability to work in multiple traction mode and sufficient design speed. Practical Value. The generalization of theoretical, scientific and methodological, experimental studies aimed

  20. [Sport and health].

    Science.gov (United States)

    Pène, Pierre; Touitou, Yvan

    2009-02-01

    The report of the National Academy of Medicine named "Sport and Health" underlines the medical, social and educational dimensions of sporting activities. Various kinds of sporting practices are described: they concern the approximately 7,000 high level athletes, around 8,000 professional (licensed) sportsmen, and sporting club members (approximately 15 millions people). A large number of amateurs do not practice in any structure and therefore are neither managed in their activities nor medically followed. Some characteristics of sporting practice at various stages of life have been documented. Around 50% of the teenagers from 12 to 17 years have a sporting practice out-of-school besides the weekly three hours applied at school or college; however, the withdrawal of sporting practice by a high number of teenagers results in a sedentary lifestyle with overweight and obesity, major risks factors for health. Elderly people take a profit from a regular and medically controlled physical activity. Functional capacities are thus improved, cardiovascular risks factors among other, which results in better quality of life of the aged and delays their dependence. The benefit upon public health of sporting practice has been pointed out in the primary prevention of cardiovascular and respiratory diseases, osteoporosis, obesity, diabetes, breast and colon cancer, and mood disturbances. It is currently well acknowledged that sporting practice is an important component of public health in both primary and secondary prevention of many diseases. Deleterious effects of which the most serious is the sudden death related to a cardiovascular anomaly, which generally occurs during an important physical effort. An important sport drift is the practice of doping to improve performances through the use of hormones, anabolics, EPO, transfusions, ... When a person exceeds his/her capacities of adaptation, because of a badly adapted or a too intense drive, this overtraining results in a

  1. 关节镜下微创手术治疗运动性肩袖损伤50例康复护理%Rehabilitation nursing care in the treatment of 50 cases of sport rotator cuff injury with minimally invasive arthroscopic surgery

    Institute of Scientific and Technical Information of China (English)

    宋学良; 于红英; 钭晓帆

    2011-01-01

    目的:探讨关节镜下微创手术治疗运动性肩袖损伤患者的康复护理方法.方法:对50例运动性肩袖损伤患者行关节镜下微创手术治疗,并给予个性化心理护理、疼痛护理及有计划的阶段性康复训练.结果:50例患者均未出现肩关节僵硬强直、创伤性骨性关节炎及神经损伤等并发症.随访3个月~1.5 年,根据美国UCLA肩关节评分标准评分优35例、良10例、可5例,优良率90%.患者自我满意度高.结论:关节镜下微创手术后早期阶段性康复训练能促进肩关节功能恢复,提高手术治疗的效果.%Objective: To explore the rehabilitation nursing methods in the treatment of sport rotator cuff injury with minimally invasive arthroscopic surgery. Methods: 50 patients with sport rotator cuff injury were treated with minimally invasive arthroscopic surgery and given individualized psychological care, pain care and planned staged rehabilitation training. Results: There was no occurrence of stiffness and rigidity of shoulder joint, traumatic osteoarthritis and nerve damage in these 50 patients. The patients were followed up for 3 months to 1.5 years, the scoring showed 35 cases were excellent, 10 cases good and 5 cases fair according to U.S. UCLA shoulder grading standard. The excellent and good rate was 90%. The patient's self - satisfaction was high. Conclusions: The early staged rehabilitation training can promote the functional recovery of shoulder joint and improve surgical outcome after minimally invasive arthroscopic surgery.

  2. Landing Gear Door Liners for Airframe Noise Reduction

    Science.gov (United States)

    Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)

    2014-01-01

    A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

  3. STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The wear and destruction appearances of hobs are researched. The reasons of the wear and destruction of hobare analyzed. And the influence of the change of the hobbing force and the hobbing temperature on the wear and destruc-tion of hob in gear hobbing is also analyzed. In gear hobbing, the main wear mechanisms are adhesion and ploughingwhen cutting the 20CrMnTi gear using W 18Cr4V high-speed steel hob.

  4. Analysis of camshaft gear transmission for a ship engine

    OpenAIRE

    Closs, Katrine Fosdal

    2015-01-01

    This thesis investigates the dynamic behavior of a spur gear pair. The gears studied are somewhat similar to the ones found in Bergen Engines medium-speed diesel engine with regards to design, but some assumptions have been made when it comes to stiffness and damping. Gear components are an important part in advanced machines and have been a subject of studies due to increasing demands for higher performance and reliability and noise control. At first a dynamic model of a sp...

  5. Lifetimes and Reliabilities of Bevel-Gear Drive Trains

    Science.gov (United States)

    Lewicki, D.; Cox, J.; Savage, M.; Brikmanis, C.

    1986-01-01

    Statistical methods used to predict system lifetimes from component lifetimes. Report shows how to use information to determine system life of drive train, using methods of probability and statistics. Presents life and reliability model for bevel-gear drive trains. Bevel-gear and support-bearing lives analyzed for each gear and bearing in drive train, with results statistically combined to produce system life for entire drive train. Numerical example included.

  6. Strength Check Analysis for Gear Shaft of Automobile Transmission

    OpenAIRE

    Yongxiang Li; Weiqiang Xia; Liwen Nan; Youjia Zhao; Fujin Yu

    2013-01-01

    As the main drive components of the automobile transmission, the performance of gear shaft plays an important role on transmission performance. Aiming at the existing problems of the traditional strength check method of gear shaft, the objective of this study is to take a five-speed transmission as an example, to accomplish the strength analysis of gear shaft of the automobile transmission based on the MASTA software. Furthermore, the simulation modeling of the transmission is built completel...

  7. Tool Gear: Infrastructure for Building Parallel Programming Tools

    Energy Technology Data Exchange (ETDEWEB)

    May, J M; Gyllenhaal, J

    2002-12-09

    Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.

  8. Influence of material and gear parameters on the safety of gearing in metallurgical industry

    Directory of Open Access Journals (Sweden)

    S. Medvecká - Beňová

    2015-01-01

    Full Text Available This paper deals with the appropriate choice of parameters to obtain the desired level of safety of gears in a gearbox to drive the conveyor in the metallurgical industry under increased load. Steel with surface hardness up to 350 HBW, or heat treated steel with hardness of 500 - 650 HBW are used. As a final heat treatment are used surface hardening, cementation and hardening, nitridation. Good properties of heat-treated steels are at the correct thickness of the heat-treated layer of the tooth. Results are presented for dual-ratio gearbox with spur gears from operation of an integrated steel company.

  9. Magnet-Sleeve-Sealed Mini Trochoidal-Gear Pump Prototype with Polymer Composite Gear

    Directory of Open Access Journals (Sweden)

    Pedro Javier Gamez-Montero

    2017-09-01

    Full Text Available The trochoidal-gear technology has been growing in groundbreaking fields. Forthcoming applications are demanding to this technology a step forward in the conceiving stage of positive displacement machines. The compendium of the qualities and the inherent characteristics of trochoidal-gear technology, especially towards the gerotor pump, together with scale/size factor and magnetic-driven transmission has led to the idea of a magnet-sleeve-sealed variable flow mini trochoidal-gear pump. From its original concept, to the last phase of the design development, the proof of concept, this new product will intend to overcome problems such as noise, vibration, maintenance, materials, and dimensions. The paper aims to show the technological path followed from the concept, design, and model, to the manufacture of the first prototype, where the theoretical and numerical approaches are not always directly reflected in the prototype performance results. Early in the design process, from a standard-commercial sintered metal mini trochoidal-gear unit, fundamental characteristics and dimensional limitations have been evaluated becoming the strategic parameters that led to its configuration. The main technical challenge to confront is being sealed with non-exterior driveshaft, ensuring that the whole interior is filled and wetted with working fluid and helping the hydrodynamic film formation, the pumping effect, and the heat dissipation. Subsequently, the mini pump architecture, embodiment, methodology, materials, and manufacture are presented. The trend of applications of polymer composite materials and their benefits wanted to be examined with this new mini pump prototype, and a pure polyoxymethylene mini trochoidal-gear set has been designed and manufactured. Finally, both the sintered and the polymer trochoidal-gear units have been experimentally tested in an in-house full-instrumented mini test bench. Although the main goal of the presented work is the

  10. Lung surgery

    Science.gov (United States)

    ... Pneumonectomy; Lobectomy; Lung biopsy; Thoracoscopy; Video-assisted thoracoscopic surgery; VATS ... You will have general anesthesia before surgery. You will be asleep and unable to feel pain. Two common ways to do surgery on your lungs are thoracotomy and video- ...

  11. Turbinate surgery

    Science.gov (United States)

    Turbinectomy; Turbinoplasty; Turbinate reduction; Nasal airway surgery; Nasal obstruction - turbinate surgery ... There are several types of turbinate surgery: Turbinectomy: All or ... This can be done in several different ways, but sometimes a ...

  12. Cataract Surgery

    Science.gov (United States)

    ... and Videos: What Do Cataracts Look Like? Cataract Surgery Written By: Kierstan Boyd Reviewed By: Elena M ... how they work. What to expect with cataract surgery Before surgery: Your ophthalmologist will measure your eye ...

  13. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... Healthy Breakfasts Shyness A Guide to Eating for Sports KidsHealth > For Teens > A Guide to Eating for Sports Print A A A What's in this article? ... Excellence There's a lot more to eating for sports than chowing down on carbs or chugging sports ...

  14. The Development of Sports Medicine.

    Science.gov (United States)

    Waddington, Ivan

    1996-01-01

    The development of sports medicine was influenced by medicalization and increasing competitiveness in modern sport, with sports physicians helping to develop performance enhancing drugs and techniques. This paper discusses sports medicine and drug use in Eastern European countries, early development of anabolic steroids in the United States, and…

  15. Guide to Eating for Sports

    Medline Plus

    Full Text Available ... for You Shyness A Guide to Eating for Sports KidsHealth > For Teens > A Guide to Eating for Sports Print A A A What's in this article? ... Excellence There's a lot more to eating for sports than chowing down on carbs or chugging sports ...

  16. Sport in the Netherlands 2009

    NARCIS (Netherlands)

    Annet Tiessen-Raaphorst; Koen Breedveld

    2009-01-01

    Sport is a popular pastime in the Netherlands; More than 10 million people take part in at least one sport. To do this, they can choose from more than 27,000 non-profit sports clubs, or more than 7,200 commercial providers such as fitness centres or riding stables. Among the most popular sports are

  17. Sport Nutritionist: A New Sport Education Role

    Science.gov (United States)

    Martin, Matthew R.; Zimmerman, Ryan; Ciotto, Carol

    2015-01-01

    Considering the challenges associated with adolescent obesity and the need for innovative and meaningful physical education curricula, the authors of this article decided to create a new sport education role to help students learn about the fundamental nutritional concepts and practices that contribute to a healthy and active lifestyle. The new…

  18. Sport Nutritionist: A New Sport Education Role

    Science.gov (United States)

    Martin, Matthew R.; Zimmerman, Ryan; Ciotto, Carol

    2015-01-01

    Considering the challenges associated with adolescent obesity and the need for innovative and meaningful physical education curricula, the authors of this article decided to create a new sport education role to help students learn about the fundamental nutritional concepts and practices that contribute to a healthy and active lifestyle. The new…

  19. Nutrition for winter sports.

    Science.gov (United States)

    Meyer, Nanna L; Manore, Melinda M; Helle, Christine

    2011-01-01

    Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered.

  20. Genetics & sport: bioethical concerns.

    Science.gov (United States)

    Miah, Andy

    2012-12-01

    This paper provides an overview of the ethical issues pertaining to the use of genetic insights and techniques in sport. Initially, it considers a range of scientific findings that have stimulated debate about the ethical issues associated with genetics applied to sport. It also outlines some of the early policy responses to these discoveries from world leading sports organizations, along with knowledge about actual use of gene technologies in sport. Subsequently, it considers the challenges with distinguishing between therapeutic use and human enhancement within genetic science, which is a particularly important issue for the world of sport. Next, particular attention is given to the use of genetic information, which raises questions about the legitimacy and reliability of genetic tests, along with the potential public value of having DNA databanks to economize in health care. Finally, the ethics of gene transfer are considered, inviting questions into the values of sport and humanity. It argues that, while gene modification may seem conceptually similar to other forms of doping, the requirements upon athletes are such that new forms of enhancement become increasingly necessary to discover. Insofar as genetic science is able to create safer, more effective techniques of human modification, then it may be an appealing route through which to modify athletes to safeguard the future of elite sports as enterprises of human excellence.

  1. MANAGEMENT OF SPORT COMPLEXES

    Directory of Open Access Journals (Sweden)

    Marian STAN

    2015-07-01

    Full Text Available The actuality of the investigated theme. Nowadays, human evolution, including his intellectual development, proves the fact that especially the creation manpower and the employment was the solution of all life’s ambitions in society. So, the fact is that in reality, man is the most important capital of the society. Also, in an individual’s life, the practice of sport plays a significant role and that’s why the initiation, the launch and the management of sports complexes activity reveal the existence of specific management features that we will identify and explain in the current study. The aim of the research refers to the elaboration of a theoretical base of the management of the sport complexes, to the pointing of the factors that influence the efficient existence and function of a sport complex in our country and to the determination of the responsibilities that have a manager who directs successfully the activity of the sport complexes. The investigation is based on theoretical methods, such as: scientific documentation, analysis, synthesis, comparison and on empirical research methods, like: study of researched literature and observation. The results of the research indicate the fact that the profitability of a sport complex must assure a particular structure to avoid the bankruptcy risk and also, that the administration of the sport complexes activity must keep in view the reliable functions of the contemporaneous management.

  2. The theory and practice of worm gear drives

    CERN Document Server

    Dudás, Ilés

    2005-01-01

    Worm gears are special gears that resemble screws, and can be used to drive other gears. Worm gears, enable two non-touching shafts in a machine to mesh (join) together. This publication, unique in that it combines both theoretical and practical design aspects, including the latest results of research and development, provides detailed treatment of the theory and production of worm drives, as well as the overarching subject of production geometry of helicoidal surfaces.Included are mathematical models for a number of practical applications; a description of dressing equipment r

  3. Study of novel concepts of power transmission gears

    Science.gov (United States)

    Rivin, Eugene I.

    1991-01-01

    Two concepts in power transmission gear design are proposed which provide a potential for large noise reduction and for improving weight to payload ratio due to use of advanced fiber reinforced and ceramic materials. These concepts are briefly discussed. Since both concepts use ultrathin layered rubber-metal laminates for accommodating limited travel displacements, properties of the laminates, such as their compressive strength, compressive and shear moduli were studied. Extensive testing and computational analysis were performed on the first concept gears (laminate coated conformal gears). Design and testing of the second conceptual design (composite gear with separation of sliding and rolling motions) are specifically described.

  4. Diagnostics of power transmissions system with tooth gear

    Directory of Open Access Journals (Sweden)

    Grzegorz WOJNAR

    2008-01-01

    Full Text Available This paper presents results of laboratory tests that were aimed at detecting early stages of various faults in toothed wheels by measurement and analysis of transverse vibration speed of the transmission gear shafts. In experimental investigation, cracking of the root tooth and chipping of the tooth were detected. The laser vibrometer Ometron VH300+ was used for non-contact measurement of shaft transversal vibration speed. Gear vibrations were recorded in selected points of gear housing and gear shafts at different speeds and gear loads. Results were analyzed and compared but in this paper is presented only selected examples. This paper shows that on the basis of the transverse vibration speed of transmission gear shafts, it is possible to detect defects at an earlier stage than on the basis of the housing vibration accelerations. In the case of measuring gear shaft vibration velocity, the way of the signal generated by the defect of a gear wheel (or bearing is shortened as well as the influence of composed transmittance of the bearing-gear housing system is eliminated. WV time-frequency analysis and complex continuous wavelet transformations were used for detection. The authors introduced a measure of local tooth damage, which was proportional to the size of damage. The results of research presented in this paperconfirmed that the defect's measure is very sensitive to the development of teeth faults.

  5. Effect of contact ratio on spur gear dynamic load

    Science.gov (United States)

    Liou, Chuen-Huei; Lin, Hsiang Hsi; Oswald, Fred B.; Townsend, Dennis P.

    A computer simulation is presented which shows how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented was performed using the NASA gear dynamics code, DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low contact ratio gears (contact ratio less than 2.0), increasing the contact ratio reduced the gear dynamic load. For high contact ratio gears (contact ratio = or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high contact ratio gears minimized dynamic load better than low contact ratio gears.

  6. Numerical Simulation on Carburizing and Quenching of Gear Ring

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The carburizing process of the gear ring was simulated by taking into account the practical carburizing and quenching techniques of the gear ring and by solving the diffusion equation. The carbon content distribution in the carburized layer was obtained. Based on the results, the quenching process of the gear ring was then simulated using the metallic thermodynamics and FEM; it was found that the carburization remarkably affects the quenching process.Microstructures and stress distributions of the gear ring in the quenching process were simulated, and the results are confirmed by experiments.

  7. High oleic sunflower oil as a gear lubricant

    OpenAIRE

    Vižintin, Jože; Kržan, Boris

    2015-01-01

    A formulated high oleic sunflower oil was investigated with respect to their expected performance in gear boxes in comparison to a typical mineral oil. Investigations of scuffing load capacity, pitting resistance and low-speed high-load wear resistance were performed by using the FZG gear test rig. In addition of standardized tests, new formulated ISO VG 46 oil was tested in a spur gear test rig. A set of spur gears was rotated at a specified load for 1,000 hours. The physical and chemical pr...

  8. Offset Compound Gear Inline Two-Speed Drive

    Science.gov (United States)

    Stevens, Mark A. (Inventor); Handschuh, Robert F. (Inventor); Lewicki, David G. (Inventor)

    2014-01-01

    A two-speed transmission having an input shaft and an output shaft, the transmission being capable of transitioning between fixed ratios, the high-range ratio being direct 1:1 and the low-range ratio being about 2:1. The transmission is a simple lightweight, yet robust, configuration utilizing only two gear meshes, being comprised of an input gear, a cluster gear, and an output gear. The transmission is controlled with a clutch and a sprag and with the input and output shafts turning in the same direction.

  9. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    Science.gov (United States)

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  10. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    Science.gov (United States)

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  11. Sports and arrhythmias.

    Science.gov (United States)

    Giada, F; Conte, R; Pescatore, V; Brugin, E

    2011-06-01

    Rhythm disorders represent the main challenge for the sport physician and cardiologist to grant the certificate of sports eligibility to the athletes. Arrhythmias that occur in athletes can be divided into two types. The most common are generally an expression of morphofunctional changes in the athlete's heart and are represented by certain forms of non-complex tachyarrhythmias and bradyarrhythmias. On the other hand you may encounter less frequently more complex arrhythmias that may be an epiphenomenon of cardiomyopathy can cause sudden death during sports activities. By collection of detailed medical history, careful examination, and in particular by the 12-lead electrocardiogram is already possible to understand the arrhythmic risk sporting population. After an analysis of main types of arrhythmias encountered in the athlete and the main diagnostic methods, this study focuses on the interplay between forms of arrhythmias, arrhythmogenic heart diseases and activity sports. Surely the increased adrenergic tone and anatomical and functional alterations sports-related favor the development of arrhythmia and sudden death risk in structural cardiomyopathies. But this is not yet resolved the question of whether sport is able to increase the incidence of ventricular arrhythmias in a normal heart. Dangerousness of the arrhythmia is variable depending on the sport is practiced with high intensity or not. Even if it is important considering the possibility of syncope in hazardous environments. Arrhythmias at risk impose the exclusion of the athlete from the practice of sport. In some cases it may be considered a drug treatment, ablation, and in rare and selected cases, the implantation of a pacemaker or an implantable defibrillator.

  12. EFFECT OF GEAR WIDTH AND HELIX ANGLE ON FACTOR OF DYNAMIC LOAD OF DOUBLE CIRCULAR ARC HELICAL GEARING

    Institute of Scientific and Technical Information of China (English)

    Wu Baolin

    2004-01-01

    Based on theory of mechanical dynamics, meshing characteristic as well as the dynamic model of double circular arc helical gearing, an analysis approach and a computer program have been developed for studying the state of dynamic load and factor of dynamic load of the gearing, the changing situation of dynamic load and dynamic load factor vs some affecting factors such as gear width, helix angle and accuracy grade etc are investigated. A series of conclusions are obtained: ①With the increasing in the values of gear width, the dynamic load factor appears slow decreasing tendency in most region of gear width. ② When the accuracy grades of the gearing are improved, the values of dynamic load factor decrease. ③ The value of dynamic load factor appears a decreasing tendency with the increasing of value of helix angle at the same ratio of critical rotational speed.

  13. Athletic pubalgia (sports hernia).

    Science.gov (United States)

    Litwin, Demetrius E M; Sneider, Erica B; McEnaney, Patrick M; Busconi, Brian D

    2011-04-01

    Athletic pubalgia or sports hernia is a syndrome of chronic lower abdomen and groin pain that may occur in athletes and nonathletes. Because the differential diagnosis of chronic lower abdomen and groin pain is so broad, only a small number of patients with chronic lower abdomen and groin pain fulfill the diagnostic criteria of athletic pubalgia (sports hernia). The literature published to date regarding the cause, pathogenesis, diagnosis, and treatment of sports hernias is confusing. This article summarizes the current information and our present approach to this chronic lower abdomen and groin pain syndrome.

  14. Aleatorism and Sporting Performance

    Directory of Open Access Journals (Sweden)

    Kosiewicz Jerzy

    2017-03-01

    Full Text Available A sporting spectacle is an important cultural event, essentially influencing social and individual lives. In spite of this, there does not yet exist a monograph that analyzes, describes, and explains sporting performance from the point of view of aleatorism as part of the theory of sport and physical culture. Unfortunately, no monograph has developed this issue in a multi-aspectual, holistic, culturological, and philosophical way, dealing with its axiological values (aesthetic and praxeological. This applies to the relations between this phenomenon and the mechanisms that bring about the development and growth of interest in the social dimension.

  15. Dietary supplements in sport.

    Science.gov (United States)

    Burke, L M; Read, R S

    1993-01-01

    Studies of the dietary practices of athletes report that nutritional supplements are commonly used. Supplementation practices vary between sports and individual athletes; however, there is evidence that at least some athletes use a large number of supplements concurrently, often in doses that are very high in comparison with normal dietary intakes. In exploring supplementation practices we propose a classification system separating the supplements into dietary supplements and nutritional erogogenic aids. The dietary supplement is characterised as a product which can be used to address physiological or nutritional issues arising in sport. It may provide a convenient or practical means of consuming special nutrient requirements for exercise, or it may be used to prevent/reverse nutritional deficiencies that commonly occur among athletes. The basis of the dietary supplement is an understanding of nutritional requirements and physiological effects of exercise. When the supplement is used to successfully meet a physiological/nutritional goal arising in sport it may be demonstrated to improve sports performance. While there is some interest in refining the composition or formulation of some dietary supplements, the real interest belongs to the use or application of the supplement; i.e. educating athletes to understand and achieve their nutritional needs in a specific sports situation. The sports drink (carbohydrate-electrolyte replacement drink) is a well known example of a dietary supplement. Scientific attitudes towards the sports drink have changed over the past 20 years. Initial caution that carbohydrate-electrolyte fluids compromise gastric emptying during exercise has now been shown to be unjustified. Numerous studies have shown that 5 to 10% solutions of glucose, glucose polymers (maltodextrins) and other simple sugars all have suitable gastric emptying characteristics for the delivery of fluid and moderate amounts of carbohydrate substrate. The optimal

  16. Doping control in sport

    DEFF Research Database (Denmark)

    Overbye, Marie Birch

    2016-01-01

    Doping testing is a key component enforced by anti-doping authorities to detect and deter doping in sport. Policy is developed to protect athletes' right to participate in doping-free sport; and testing is a key tool to secure this right. Accordingly, athletes' responses to anti-doping efforts...... a web-based questionnaire (N = 645; response rate 43%) and uses qualitative findings to elaborate on and explain quantitative results. Results showed that two-thirds of the athletes reported the national testing programme in their sport to be appropriate. A majority of the athletes who had an opinion...

  17. SPORT AND EXERCISE PSYCHOLOGY

    Directory of Open Access Journals (Sweden)

    Andy Lane

    2008-09-01

    Full Text Available DESCRIPTION The book introduces the undergraduate psychology student to both academic and professional aspects of Sport and Exercise Psychology. It uses up to date research evidence, established theory and a variety of activities that help the student consider and understand academic and professional aspects of this particular academic discipline. PURPOSE The book aims to provide the undergraduate psychology student with a structured introduction to the subject area and an insight into the theoretical evidence and practical suggestions that underpin what a Sport and Exercise psychologist does. The book also aims to support one term or one semester courses in Sport and Exercise Psychology. It is also appropriate for Masters level courses. FEATURES The book begins with a chapter on applied sports psychology to give the reader an insight into the domain of sport psychology, providing an overview of the techniques that could be used. The next three chapters focus on mood, anxiety and self confidence, which influence performance. This leads on to four chapters that focus on managing psychological states. There is also a chapter on leadership which interestingly includes leadership development in coaches and in athletes. Two chapters focus on the effects of exercise on psychological states, providing a balance between the benefits and potential drawbacks. The final chapter examines the issue of placebo effects. Throughout each chapter there are useful activities than can help the reader's understanding of practical and theoretical issues. These also have practical implications for the work of a Sport and Exercise Psychologist. Key ethical issues are raised on a regular basis throughout the text. The book offers an excellent blend of theory and practical suggestions which are critically discussed thus giving valuable insights regarding the research process and applied practice which is often lacking in the more well known standard textbooks for Sport

  18. Sports participation in adults with congenital heart disease

    NARCIS (Netherlands)

    P. Opic (Petra); E.M.W.J. Utens (Elisabeth); J.A.A.E. Cuypers (Judith); M. Witsenburg (Maarten); A.E. van den Bosch (Annemien); Domburg, R.V. (Ron Van); A.J.J.C. Bogers (Ad); H. Boersma (Eric); Pelliccia, A. (Antonio); J.W. Roos-Hesselink (Jolien)

    2015-01-01

    textabstractBackground: It is unclearwhether sports participation in adultswith repaired congenital heart disease is safe and has benefits. Methods: Congenital heart disease (ConHD) patients who underwent corrective surgery for Atrial Septal Defect, Ventricular Septal Defect, Pulmonary Stenosis, Tet

  19. Determination of the ISO face load factor in spur gear drives by the finite element modeling of gears and shafts

    OpenAIRE

    2013-01-01

    The face load factor is a common coefficient used in gear design standards that takes into account the uneven distribution of load across the face width of the gears caused by the mesh misalignment. In this paper, a finite element model that includes the gears and the corresponding shafts is proposed. The results obtained from the application of finite element analysis to this model are compared with those obtained from application of the ISO Standard 6336 coefficient-based method (Method C)....

  20. Influence of tooth profile error in gear rattle (2nd report; In the case of multi-step gear system)

    OpenAIRE

    濱野, 崇; 吉武, 裕; 田村, 尋徳; 濵田, 知宏; 原田, 晃; 小林, 敦

    2009-01-01

    Gear rattle of multi-step helical gear system is treated. Mesh stiffness variations and tooth profile errors are considered within the system. The effects of mesh stiffness variations, the ratio of static torque to dynamic one and tooth profile errors on the rattle are studied by a highly accurate numerical analysis called the shooting method. As a result, the followings were made clear. (1) Because of the tooth profile errors, the amplitude of resonances like gear noise becomes large and the...

  1. Variables associated with return to sport following anterior cruciate ligament reconstruction: a systematic review.

    Science.gov (United States)

    Czuppon, Sylvia; Racette, Brad A; Klein, Sandra E; Harris-Hayes, Marcie

    2014-03-01

    As one of the purposes of anterior cruciate ligament reconstruction (ACLR) is to return athletes to their preinjury activity level, it is critical to understand variables influencing return to sport. Associations between return to sport and variables representing knee impairment, function and psychological status have not been well studied in athletes following ACLR. The purpose of this review was to summarise the literature reporting on variables proposed to be associated with return to sport following ACLR. Systematic review. Medline, EMBASE, CINAHL and Cochrane databases were searched for articles published before November 2012. Articles included in this review met these criteria: (1) included patients with primary ACLR, (2) reported at least one knee impairment, function or psychological measure, (3) reported a return to sport measure and (4) analysed the relationship between the measure and return to sport. Weak evidence existed in 16 articles suggesting variables associated with return to sport included higher quadriceps strength, less effusion, less pain, greater tibial rotation, higher Marx Activity score, higher athletic confidence, higher preoperative knee self-efficacy, lower kinesiophobia and higher preoperative self-motivation. Weak evidence supports an association between knee impairment, functional and psychological variables and return to sport. Current return to sport guidelines should be updated to reflect all variables associated with return to sport. Utilising evidence-based return to sport guidelines following ACLR may ensure that athletes are physically and psychologically capable of sports participation, which may reduce reinjury rates and the need for subsequent surgery.

  2. The nature of sports marketing

    OpenAIRE

    Bühler, André; Nufer, Gerd; Rennhak, Carsten

    2006-01-01

    Sports marketing has established itself over the last three decades not only as a very special form of marketing but also as an own subject of research. However, it is quite surprising that the nature of sports marketing is relatively unknown as different definitions of sports market-ing indicate. Indeed, a generally accepted definition does not exist to date and opinions about the nature of sports marketing differ widely. This paper examines the nature of sports market-ing and therefore seek...

  3. Why Do Sports Officials Dropout?

    OpenAIRE

    Dosseville, Fabrice; Rioult, François; Laborde, Sylvain

    2013-01-01

    International audience; Sports officials' recruitment and retention is currently an issue for many sports. The sources of stress are numerous but seem to have a reduced impact on sport officials' dropout. To examine potential reasons of sport officiating dropout, 1718 sport officials were asked to fill a survey about their motivation, the way they trained and are evaluated, perceived stress, the qualities and skills required for officiating, and how they live their function, for a total of 13...

  4. ETHICS AND CHANGES IN SPORT

    OpenAIRE

    Jovo Radoš; Milan Nešić

    2008-01-01

    Ethics, as a practical philosophy, is found in essential relationships and relations with other relevant practical disciplines (economics, law, politics, sport, etc.). Every human activity is ethically grounded. Therefore, human ethics, which includes sport ethics, is one of the fundamental criteria for establishing moral relations in different are as of sport life. Sport morale stems from a universally accepted ethics legal principles that aim at maintaining sport spirit based on the Olympic...

  5. Weight Loss Surgery (Bariatric Surgery) (For Parents)

    Science.gov (United States)

    ... to Be Smart About Social Media Weight Loss Surgery (Bariatric Surgery) KidsHealth > For Parents > Weight Loss Surgery (Bariatric Surgery) ... bariatric surgery might be an option. About Bariatric Surgery Bariatric surgery had its beginnings in the 1960s, ...

  6. Method and Device for Speed Change by the Epicyclic Gear Train with Stepped-Planet Gear Set

    Directory of Open Access Journals (Sweden)

    Malashchenko Volodymyr

    2016-08-01

    Full Text Available The article describes new method and device for continuously variable speed change management via compound epicyclic gearing with composite planet gears and closed circuit hydrosystem, when the speed control element is either outer ring gear (annulus or the carrier or sun gear. In each case, the control element connected to closed circuit hydrosystem and can be in motion or immovable depending on the bandwidth of hydrosystem’s regulating throttle. We had held theoretical research and received graphic dependences between velocities of driving, control and driven elements by means of computer programing.

  7. Optimum Design of 1st Gear Ratio for 4WD Vehicles Based on Vehicle Dynamic Behaviour

    OpenAIRE

    M. H. Shojaeefard; Talebitooti,R.; Sadegh Yarmohammadi Satri

    2013-01-01

    This paper presents an approach that allows optimizing gear ratio and vehicle dimension to achieve optimum gear transmission. Therefore, augmented Lagrangian multiplier method, defined as classical method, is utilized to find the optimum gear ratios and the corresponding number of gear teeth applied to all epicyclical gears. The new method is able to calculate and also to optimize the gear ratio based on dynamics of 4WD vehicles. Therefore, 4WD vehicles dynamic equations are employed assuming...

  8. Mathematical and Finite Element Modeling of Micro-Modification for Marine Gear

    OpenAIRE

    Xiongxi Wu; Qifeng Gao; Zesong Li

    2015-01-01

    Based on the computer simulation technique, this paper used the professional gear design software MASTA and finite element software ANSYS combined with the method of gear micro-modification to redesign the gear profile and eventually realized the optimization design of gear micro-modification. Then the gear transmission model of one-level reducer was established to simulate and analyze the contact equivalent stress, transmission error, and meshing impact before and after gear modification. By...

  9. Improving bending stress in spur gears using asymmetric gears and shape optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2010-01-01

    Bending stress plays a significant role in gear design wherein its magnitude is controlled by the nominal bending stress and the stress concentration due to the geometrical shape. The bending stress is indirectly related to shape changes made to the cutting tool. This work shows that the bending...

  10. VARIABLE GEARING IN A BIOLOGICALLY-INSPIRED PNEUMATIC ACTUATOR ARRAY

    Science.gov (United States)

    Azizi, Emanuel; Roberts, Thomas J.

    2013-01-01

    A fundamental feature of pennate muscles is that muscle fibers are oriented at an angle to the line of action and rotate as they shorten, becoming more oblique throughout a contraction. This change in fiber orientation (pennation angle) can amplify the shortening velocity of a fiber and increase output velocity of the muscle. The velocity advantage resulting from dynamic changes in pennation angle can be characterized as a gear ratio (muscle velocity/fiber velocity). A recent study has shown that a pennate muscle’s gear ratio varies automatically depending on the load such that a muscle operates with a high gear during rapid contractions and low gear during forceful contractions. We examined whether this variable gearing behavior can be replicated in a pennate array of artificial muscles. We used McKibben type pneumatic actuators, which shorten in tension when filled with compressed gas. Similar to muscle fibers, the actuators expand radially during shortening, a feature thought to be a critical part of the variable gearing mechanism in pennate muscles. We arranged McKibben actuators in an array oriented to mimic a pennate muscle, and quantified the system’s gear ratio during contraction against a range of loads. Video was used to measure the gear ratio during each contraction. We find that similar to pennate muscles, the gear ratio decreases significantly with increasing load and that variable gearing results from load-dependent variation in the amount of actuator rotation. These results support the idea that variable gearing in pennate muscles is mediated by difference is fiber rotation and the direction of muscle bulging. The behavior of our artificial muscle array also highlights the potential benefits of bio-inspired architectures in artificial muscle arrays, including the ability to vary force and speed automatically in response to variable loading conditions. PMID:23462288

  11. Sport Fishing Regulations

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The regulations for sport fishing on St. Vincent National Wildlife Refuge are outlined in this document. Fishing is only permitted from sunrise to sunset, and only...

  12. Sports and Concussion

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Concussion Sports and Concussion Past Issues / Summer 2015 Table of Contents For ... vital to a healthy life. What Is a Concussion? A concussion is a type of traumatic brain ...

  13. Photobiomodulation on sports injuries

    Science.gov (United States)

    Liu, Xiao-Guang; Liu, Timon C.; Jiao, Jian-Ling; Li, Cheng-Zhang; Xu, Xiao-Yang

    2003-12-01

    Sports injuries healing has long been an important field in sports medicine. The stimulatory effects of Low intensity laser (LIL) irradiation have been investigated in several medical fields, such as cultured cell response, wound healing, hormonal or neural stimulation, pain relief and others. The aim of this study was to evaluate whether LIL irradiation can accelerate sports injuries healing. Some experimental and clinical studies have shown the laser stimulation effects on soft tissues and cartilage, however, controversy still exists regarding the role of LIL when used as a therapeutic device. Summarizing the data of cell studies and animal experiments and clinic trials by using the biological information model of photobiomodulation, we conclude that LIL irradiation is a valuable treatment for superficial and localized sports injuries and that the injuries healing effects of the therapy depend on the dosage of LIL irradiation.

  14. SPORTS TOURISM, LEISURE METHOD

    Directory of Open Access Journals (Sweden)

    DURBĂCEA-BOLOVAN MARIAN

    2013-08-01

    Full Text Available The process of using free time in nature tourism as recreation or sport activity and is a socio-economicphenomenon of mass, including relationships and activity occurring within a country and the material and spiritualflow between countries.Sports tourism is a subset of an industry generating capital, jobs and creating the image of a country /region. This article is aimed primarily a statistical analysis of this form of tourism at national and European levelwith which we wish to note that although Romania has various forms of relief , and such an arrangement it is a bigadvantage , though no have been major investments in this type of tourism .The development of increasingly high global sports movement, the emergence of new destinations, thedevelopment of road and air transport modes and infrastructure and the development of the Internet, all contributeto the development of sports tourism.

  15. Sports related ocular injuries.

    Science.gov (United States)

    Mishra, Avinash; Verma, Ashok K

    2012-07-01

    Every year > 600,000 sports and recreation related eye injuries occur, out of which roughly 13,500 of these result in permanent loss of sight. Up to 90% of these sports related eye injuries are preventable by using adequate eye protection equipment. Protective eyewear is made of polycarbonate, a highly impact-resistant plastic which is now easily available as prescription and non-prescription eyewear and all players should be encouraged to use them. The medical officers by educating their patients regarding the risks of eye injuries in various sports and the confirmed benefits of using protective equipment have the potential to prevent injury to over thousands of eyes every year. The medical fraternity can also play a very important role in educating the coaches, parents, and children and thus put an end to unnecessary blindness and vision loss from sports related ocular injuries, therefore ensuring a lifetime of healthy vision.

  16. Sports and Your Eyes

    Science.gov (United States)

    ... may put you at high risk for eye injuries. Baseball Basketball Water Sports Boxing Hockey Paintball Racquetball Softball Squash Fencing Lacrosse Wrestling Football Golf Badminton Soccer Tennis Fishing Bicycling Gymnastics Track ...

  17. Parenting in sport.

    Science.gov (United States)

    Knight, Camilla J; Berrow, Steffan R; Harwood, Chris G

    2017-08-01

    This paper provides a brief summary and commentary on the growing literature on parenting in sport, with a particular emphasis on literature from the last 2-3 years. Following a brief introduction overviewing the topic area, we firstly focus on the influence of parental involvement on children. Specifically, we examine the range of factors that influence children's perceptions of parental involvement and the consequences of different behaviors. Next we discuss the factors influencing parental involvement, such as the challenges and stressors associated with parenting children in sport and the culture within different sports. Finally, our review focuses upon the strategies developed by parents to facilitate their involvement in their children's sport, as well as the few papers focused upon parent education and support. We conclude by examining the need for further research and examination of support strategies for parents. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  18. Preventing Children's Sports Injuries

    Science.gov (United States)

    ... might not be possible to return to the sport without risking further injury. Because overuse injuries are characterized by swelling, a doctor may prescribe rest, medicines to ease inflammation, and physical therapy. When recovery is complete, your child's technique or ...

  19. Sports and Child Development

    National Research Council Canada - National Science Library

    Felfe, Christina; Lechner, Michael; Steinmayr, Andreas

    2016-01-01

    .... Yet, the role of extra-curricular activities has received little attention. This study analyzes the effect of participation in sports clubs-one of the most popular extra-curricular activities among children...

  20. THE DOCTOR'S SPORTS BAG

    African Journals Online (AJOL)

    Enrique

    Controlled drugs — obey rules of country of sports event ... tainly determine the content and amount of trauma treatment equipment needed. Covering an .... Check for expired drugs every 6 months. .... Date on which transaction occurred.

  1. Sport injuries in adolescents

    Science.gov (United States)

    Habelt, Susanne; Hasler, Carol Claudius; Steinbrück, Klaus; Majewski, Martin

    2011-01-01

    In spite of the wide range of injuries in adolescents during sports activities, there are only a few studies investigating the type and frequency of sport injuries in puberty. However, this information may help to prevent, diagnose and treat sports injuries among teens. 4468 injuries in adolescent patients were treated over a ten year period of time: 66,97% were boys and 32.88% girls. The most frequent sports injuries were football (31.13%) followed by handball (8.89%) and sports during school (8.77%). The lower extremity was involved in 68.71% of the cases. Knee problems were seen in 29.79% of the patients; 2.57% spine and 1.99% head injuries. Injuries consisted primarily of distortions (35.34%) and ligament tears (18.76%); 9,00% of all injuries were fractures. We found more skin wounds (6:1) and fractures (7:2) in male patients compared to females. The risk of ligament tears was highest during skiing. Three of four ski injuries led to knee problems. Spine injuries were observed most often during horse riding (1:6). Head injuries were seen in bicycle accidents (1:3). Head injuries were seen in male patients much more often then in female patients (21:1). Fractures were noted during football (1:9), skiing (1:9), inline (2:3), and during school sports (1:11). Many adolescents participate in various sports. Notwithstanding the methodological problems with epidemiological data, there is no doubt about the large number of athletes sustain musculoskeletal injuries, sometimes serious. In most instances, the accident does not happened during professional sports and training. Therefore, school teachers and low league trainer play an important role preventing further accidence based on knowledge of individual risk patterns of different sports. It is imperative to provide preventive medical check-ups, to monitor the sport-specific needs for each individual sports, to observe the training skills as well as physical fitness needed and to evaluation coaches education. PMID

  2. Sport injuries in adolescents

    Directory of Open Access Journals (Sweden)

    Susanne Habelt

    2011-11-01

    Full Text Available In spite of the wide range of injuries in adolescents during sports activities, there are only a few studies investigating the type and frequency of sport injuries in puberty. However, this information may help to prevent, diagnose and treat sports injuries among teens. 4468 injuries in adolescent patients were treated over a ten year period of time: 66,97% were boys and 32.88% girls. The most frequent sports injuries were football (31.13% followed by handball (8.89% and sports during school (8.77%. The lower extremity was involved in 68.71% of the cases. Knee problems were seen in 29.79% of the patients; 2.57% spine and 1.99% head injuries. Injuries consisted primarily of distortions (35.34% and ligament tears (18.76%; 9,00% of all injuries were fractures. We found more skin wounds (6:1 and fractures (7:2 in male patients compared to females. The risk of ligament tears was highest during skiing. Three of four ski injuries led to knee problems. Spine injuries were observed most often during horse riding (1:6. Head injuries were seen in bicycle accidents (1:3. Head injuries were seen in male patients much more often then in female patients (21:1. Fractures were noted during football (1:9, skiing (1:9, inline (2:3, and during school sports (1:11. Many adolescents participate in various sports. Notwithstanding the methodological problems with epidemiological data, there is no doubt about the large number of athletes sustain musculoskeletal injuries, sometimes serious. In most instances, the accident does not happened during professional sports and training. Therefore, school teachers and low league trainer play an important role preventing further accidence based on knowledge of individual risk patterns of different sports. It is imperative to provide preventive medical check-ups, to monitor the sport-specific needs for each individual sports, to observe the training skills as well as physical fitness needed and to evaluation coaches education.

  3. Ambush marketing and sports

    Directory of Open Access Journals (Sweden)

    Hakan Ünal

    2011-03-01

    Full Text Available The tactics used to reach to the mind of consumer who come under the messages of brands that sent from different fronts such as thousands of products (advertising, public relations, sponsorship, point of sale activities, promotion, etc differentiates and so to say It is lived lots of brand wars. Most of these wars are seen in areas of sports organizations. Sports is always in front of consumer in every moment of the life and being in brisk demand. It is transformed into an industry which has a large-scale by adding the power of influencing the sectors connected to each other.The world's leading companies are trying to increase their market shares by benefiting from the charm of the sports. Sports is one of the most popular areas about sponsorship. Sports has the highest share in the sponsorship areas. Ambush marketing has appeared as a major threat against sports sponsorship. Ambush marketing can also be described as an attempt of making the another company's name which is a competitor related with the event without paying a high price and also without violating the laws in the situations that official sponsorship exists in an organization which is involving the massess even a brand's sporting, social or even political event.Anyway, the efforts of preventing ambush marketing applications by the event owners and sponsors becoming very hard. There is not a clear result about whether ambush marketing is an ethical application or not and if it has a positive or a negative impact on the sports marketing. Further investigations will show us whether the war against ambush marketing will be successful or not.

  4. Sports in elementary school

    OpenAIRE

    Groot, De, Julie; Moolenaar, Ben; Boers, Eralt; Mombarg,, Remo

    2016-01-01

    The aim of the project is stimulating sport participation among elementary school children in the province of Friesland. The ultimate aim is to provide three hours of physical education, provided by an physical education specialist, plus two extra hours of sport activities. Part one is about describing the differences and part two is about effective interventions after school, every week. The following instruments are used during the research: Movement Assessment Battery for Children (M-ABC-2...

  5. Sports Fever in Sangzhi

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    IT was Liu Hongyan’s bright eyes and slim figure that initially caught the eye of Liu Yuheng, the coach of Sangzhi Sports School shooting team, when she was in middle school. There were other indications that she would make a good marksman, such as her quiet character—even the neatness of her penmanship. After making persuasive overtures to Hongyan’s school and family, coach Liu Yuheng brought Hongyan to train at the Sangzhi Sports School.

  6. Sport Spaces for All

    DEFF Research Database (Denmark)

    Wagner, Anne Margrethe

    2010-01-01

    Præsentation af det digitale værktøj "Idrætsrum for alle" ved konferencen Sport-Architektur-Form i Dresden den 29-30. oktober 2010......Præsentation af det digitale værktøj "Idrætsrum for alle" ved konferencen Sport-Architektur-Form i Dresden den 29-30. oktober 2010...

  7. Nike+SportBand

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    当年Nike推出Nike+iPod Sport Kit.让人和跑鞋有了互动的交流.从而引发了当时运动达人的强烈关注。而今Nike又有了新一代的Nike+成员Nike+SportBand.如果前者让人听见奔跑.

  8. Ambush marketing and sports

    Directory of Open Access Journals (Sweden)

    Hakan Ünal

    2011-03-01

    Full Text Available The tactics used to reach to the mind of consumer who come under the messages of brands that sent from different fronts such as thousands of products (advertising, public relations, sponsorship, point of sale activities, promotion, etc differentiates and so to say It is lived lots of brand wars. Most of these wars are seen in areas of sports organizations. Sports is always in front of consumer in every moment of the life and being in brisk demand. It is transformed into an industry which has a large-scale by adding the power of influencing the sectors connected to each other.The world's leading companies are trying to increase their market shares by benefiting from the charm of the sportsSports is one of the most popular areas about sponsorship. Sports has the highest share in the sponsorship areas. Ambush marketing has appeared as a major threat against sports sponsorship. Ambush marketing can also be described as an attempt of making the another company's name which is a competitor related with the event without paying a high price and also without violating the laws in the situations that official sponsorship exists in an organization which is involving the massess even a brand's sporting, social or even political event.Anyway, the efforts of preventing ambush marketing applications by the event owners and sponsors becoming very hard. There is not a clear result about whether ambush marketing is an ethical application or not and if it has a positive or a negative impact on the sports marketing. Further investigations will show us whether the war against ambush marketing will be successful or not.

  9. Leisure Sport Participation in Cyprus

    Directory of Open Access Journals (Sweden)

    Nicos Kartakoullis

    2015-12-01

    Full Text Available This study contributes to the limited existing research on the participation patterns of Cypriots in leisure and sports. Leisure and sport are viewed collectively while adapting the notion put forth by The Council of Europe (2007 defining leisure sports as sports activities aimed at the preservation and improvement of physical condition, health and fun. The purpose of this paper is to examine the leisure sport participation patterns of Cypriots, specifically: (1 participation patterns in leisure sports, (2 reasons for participating in leisure sports, (3 cost and participation in leisure sport, (4 leisure sport spectatorship, and (5 vacationing and leisure sport experiences. Data was commissioned and collected by the Centre for Leisure, Tourism and Sports (University of Nicosia for the Cyprus Sport Organisation. A telephone-survey of 1000 Cypriots, men and women, aged 15+, from coast-to-coast in Cyprus using stratified random sampling was employed. The sample was weighted by gender, age, district and region of residence. The results indicate that: (1 almost half of the Cypriot population participates in leisure sports, (2 participation in leisure sports decreases with age, (3 participation in leisure sports tends to be driven by health benefits, (4 most Cypriots participate in leisure sport at no cost, (5 television is the most common means reported for spectatorship, and (6 some Cypriots plan their vacations around leisure sport experiences. The results indicate the relevant importance of the leisure sport culture in Cyprus while also reflecting on age and cost related factors that may influence participation in leisure sports.

  10. Topological Expression Model of Satellite Gear Mechanism

    Institute of Scientific and Technical Information of China (English)

    Yang Ping

    2005-01-01

    By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made.

  11. GEAR WHEELS THE PROCESSED BY ELECTRICAL EROSION

    Directory of Open Access Journals (Sweden)

    MARCEL S.POPA

    2015-12-01

    Full Text Available For low tooth loads and low peripheral speeds between 0.3 and 2 m / s are chosen based alloys and steels, gray cast iron. In industry are preferable ferrous alloys: bronze, brass and aluminum alloys, and where speeds and demands are low gears are made of sheet steel or alloys. Wheel group required less include some hand-operated mechanisms, such as jacks, some trolls. These wheels are larger and they are made of alloy steel, semi-hard and sometimes gray cast iron FC250, FC300.

  12. Vibration and Noise Characteristics of Elliptical Gears due to Non-Uniform Rotation

    Science.gov (United States)

    Liu, Xing; Nagamura, Kazuteru; Ikejo, Kiyotaka

    Elliptical gear is a typical non-circular gear, which transmits a variable-ratio rotation and power simultaneously. Due to the non-uniform rotation, the vibration and noise of elliptical gears demonstrate particular characteristics which should be paid attention to in practical application. In this paper, two elliptical gears, which are a single elliptical gear and a double elliptical gear, have been investigated to analyze the vibration and noise characteristics of elliptical gears. The corresponding circular gears for comparison are also investigated. General factors including the torque, the rotation speed, the gear vibration acceleration and the gear noise of the four test gears are measured by running test. The root mean square of the Circumferential Vibration Acceleration (CVA) and the sound pressure level of the noise of elliptical gears are obtained from the measured results and compared with those of circular gears to clarify the vibration and noise characteristics of elliptical gears. Furthermore, the frequency analysis of the CVA of elliptical gears is conducted by Fast Fourier Transform Algorithm (FFT) and compared with that of circular gears. The main vibration component of elliptical gear is uncovered according to the obtained frequency spectra. In addition, the Critical Rotation Speeds of Tooth Separation (CRSTS) of elliptical gear is obtained and its relation with load torque is unveiled.

  13. DYNAMIC MODELLING OF BAR-GEAR MIXED MULTIBODY SYSTEMS USING A SPECIFIC FINITE ELEMENT METHOD

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A new dynamic model for mixed, flexible bar and gear multibody systems is developed based on a specific finite element method, and a new gear-element is proposed. The gear-element can take into account the time variant stiffness, the gear errors and mass unbalance. The model for geared multibody systems can couple the gear meshing and the flexibility of all contained components. The kinematic and dynamic analyses of the geared multibody systems are expounded and illustrated on an example composed of three gears, two bars and one slider.

  14. State of development of sport and technical and applied sports in the sports organizations of Ukraine

    Directory of Open Access Journals (Sweden)

    Tikhonova N.V.

    2014-06-01

    Full Text Available Purpose : the study of the development of sport and technical and applied sports in the sports organizations of Ukraine. Material : the results of analysis of scientific and methodical literature, statistical reports of the Ministry of Youth and Sports, controls for Physical Culture and Sport, the governing bodies of education and science, society websites promoting Defence of Ukraine, the Sports Committee of Ukraine. Results : technical sports solve complex health and educational problems, promote patriotic education of children. In Ukraine today gaining popularity of sports-technical and applied sports. According to statistics the number of students enrolled in 2013 increased by 6% (1720 people in relation to 2012. Total 30484 person. The most popular among children and adolescents are: military-sport all-around (amount involved is 23.9% of the total number of pupils, fire-applied sports (8.8%, parachute (8.7%, automotive (8.1 %, model aircraft (7.8%, underwater (5.8%, radio sport (7.1%. The most abundant component in the number of sports clubs have engaged in occupations which covered 18264 children and adolescents. Conclusions : Implementation of measures for further development of sports engineering, aviation and military applied sports will foster a versatile development, hardened physically, technically trained people. As the formation of the younger generation of sustained interest and needs in the classroom technical creativity, provide training for young people for military service and active labor.

  15. Procedure for Tooth Contact Analysis of a Face Gear Meshing With a Spur Gear Using Finite Element Analysis

    Science.gov (United States)

    Bibel, George; Lewicki, David G. (Technical Monitor)

    2002-01-01

    A procedure was developed to perform tooth contact analysis between a face gear meshing with a spur pinion using finite element analysis. The face gear surface points from a previous analysis were used to create a connected tooth solid model without gaps or overlaps. The face gear surface points were used to create a five tooth face gear Patran model (with rim) using Patran PCL commands. These commands were saved in a series of session files suitable for Patran input. A four tooth spur gear that meshes with the face gear was designed and constructed with Patran PCL commands. These commands were also saved in a session files suitable for Patran input. The orientation of the spur gear required for meshing with the face gear was determined. The required rotations and translations are described and built into the session file for the spur gear. The Abaqus commands for three-dimensional meshing were determined and verified for a simplified model containing one spur tooth and one face gear tooth. The boundary conditions, loads, and weak spring constraints were determined to make the simplified model work. The load steps and load increments to establish contact and obtain a realistic load was determined for the simplified two tooth model. Contact patterns give some insight into required mesh density. Building the two gears in two different local coordinate systems and rotating the local coordinate systems was verified as an easy way to roll the gearset through mesh. Due to limitation of swap space, disk space and time constraints of the summer period, the larger model was not completed.

  16. Dynamic Analysis of Integrally Geared Compressors with Varying Workloads

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2016-01-01

    Full Text Available Integrally geared compressors are characterized by compact and high efficiency machines, which are widely used in modern processing industries. As an important part of integrally geared compressors, a geared rotor-bearing system exhibits complicated dynamic behaviors. When running at rated speeds, a coupling system likely produces resonance with an adjusted workload, and a critical load phenomenon occurs. The dynamic coefficients of bearings, axial force and torque, and gear meshing stiffness vary with workload because of the interaction between rotors. In this study, a dynamic model of a geared rotor-bearing system influenced by the dynamic coefficients of bearings, axial force and torque, and gear meshing stiffness is developed. The dynamic responses of the coupling system are calculated and analyzed by using a typical five-shaft integrally geared compressor as an example. The effects of different parameters on the dynamic behaviors of the proposed system are also considered in the discussion. The geared rotor-bearing system is further investigated to examine the failure mechanism of the critical load.

  17. 49 CFR 229.57 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 229.57 Section 229.57 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Foundation brake gear. A lever, rod, brake beam, hanger, or pin may not be worn through more than 30...

  18. New Lubricants Increase Surface-Fatigue Lives Of Gears

    Science.gov (United States)

    Townsend, Dennis P.; Shimski, John

    1995-01-01

    Report describes experimental study of effectiveness of seven oils with various additives and viscosities in prolonging surface-fatigue lives of spur gears. Experiments conducted on pairs of meshing spur gears of 3.5-in. (8.89-cm) pitch diameter, all fabricated to same specifications from same lot of steel.

  19. Involute Spur Gear Template Development by Parametric Technique ...

    African Journals Online (AJOL)

    Nekky Umera

    cylindrical coordinate systems to create the involute curve profile. Since spur gear ... with 3 module, 30 Teeth, 20° pressure angle based on parametric technique by using ... and a set of points P2 to P5 is created in the ZY plane. Joining these ..... a three-dimensional part directly from a parametric solid modeled gear file.

  20. Wear and scuffing of austempered ductile iron gears

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, L. [Departamento de Engenharia Mecanica, Instituto Superior de Engenharia, Instituto Politecnico do Porto (Portugal); Seabra, J. [Porto Univ. (Portugal). Dept. Engenharia Mecanica e Gestao Industrial

    1998-03-01

    This paper enhances actual knowledge of the properties of austempered ductile iron (ADI) as a gear material. Results from scuffing tests performed with ADI gears on a FZG test rig are presented and discussed. Contact condition analysis is done using elast-hydrodynamic theory along with several experimental techniques, as surface electronic scanning microscopy, metallurgical spectroscopy and lubricant ferrographic analysis. (orig.)