Journal articles: 'Squash rackets'

1

Buxton, J. M. "The Physics of Squash Rackets." Physics Bulletin 37, no. 4 (April 1986): 159–61. http://dx.doi.org/10.1088/0031-9112/37/4/025.

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2

Locke, Simon. "Squash rackets: a review — deadly or safe?" Medical Journal of Australia 143, no. 12-13 (December 1985): 565–67. http://dx.doi.org/10.5694/j.1326-5377.1985.tb119952.x.

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3

Kennerley-Bankes, J. L. "Squash rackets: a survey of eye injuries in England." BMJ 291, no. 6508 (November 30, 1985): 1539. http://dx.doi.org/10.1136/bmj.291.6508.1539.

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4

Wright, M. B. "Probabilities and Decision Rules for the Game of Squash Rackets." Journal of the Operational Research Society 39, no. 1 (January 1988): 91. http://dx.doi.org/10.2307/2582002.

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Wright, M. B. "Probabilities and Decision Rules for the Game of Squash Rackets." Journal of the Operational Research Society 39, no. 1 (January 1988): 91–99. http://dx.doi.org/10.1057/jors.1988.11.

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6

Wilson, J. F., and J. S. Davis. "Tennis Racket Shock Mitigation Experiments." Journal of Biomechanical Engineering 117, no. 4 (November 1, 1995): 479–84. http://dx.doi.org/10.1115/1.2794211.

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Measured in this study was the effectiveness of two types of retrofits in mitigating shocks in tennis rackets with ideally high grip fixity. The retrofits were a cushioned grip tape and a string implant device. Three types of rackets were investigated: wood, graphite composite, and metal. For low speed ball impact, neither retrofit changed significantly the magnitude and distribution of e, the coefficient of restitution on the racket heads. For moderate ball speeds impacting the rackets along the vertical centerline, three dynamic racket responses were measured: the free vibration damping based on racket head acceleration, the root-mean-square (rms) grip reaction force, and the fast Fourier transform (FFT) of the grip force. These latter experiments showed that the string implant device had a negligible effect on the three dynamic measures of racket response. However, the cushioned grip tape increased racket damping by up to 100 percent, reduced the rms grip force by about 20 percent, and reduced the magnitude of the FFT of this force by about 40 percent.

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Chen, Yu-Fen, Chien-Hung Liu, Te-Hua Fang, Chen-Chih Huang, and Chi-Fan Liu. "DEVELOPMENT OF A LASER MEASUREMENT SYSTEM FOR FLATNESS AND THICKNESS OF THE RUBBER AND RACKET." Transactions of the Canadian Society for Mechanical Engineering 37, no. 3 (September 2013): 539–47. http://dx.doi.org/10.1139/tcsme-2013-0042.

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This study analyzes the flatness of the commercial rackets measured by the modified S500 rubber thickness gauge mounted on a moving stage. A least square fitting method was used to calculate the racket flatness of these rackets. The experimental results showed the average flatness of all samples is 0.03 mm and the triple standard deviation is ±0.03 mm. The flatness of the rackets will lead to an in accurate examination of the rubber thickness before a match.

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Elliott, Bruce, Robert Marshall, and Guillermo Noffal. "The role of upper limb segment rotations in the development of racket‐head speed in the squash forehand." Journal of Sports Sciences 14, no. 2 (April 1996): 159–65. http://dx.doi.org/10.1080/02640419608727697.

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Çetinkaya, Erkan. "Dominant Hand Usage in Racket Sports and Detection of the Injured Regions." Journal of Education and Training Studies 6, no. 12 (October 22, 2018): 130. http://dx.doi.org/10.11114/jets.v6i12.3709.

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The aim of this study is to examine dominant hand usage and detect the injury regions in racket sports. A total of 98 athletes, of which 37 (37.8%) are female, 61 (62.2%) are male, studying at 11 different universities and attending competitions with schools teams with an average age of 21.11±1.66, height of 1.71±0.08 cm, weight of 64.92±10.85 kg, and BMI of 22.00±2.41(kg/m2) have participated in the study. When it comes to the distribution of the athletes by branches, the sample consists of 22 table tennis players, 24 badminton players, 25 tennis players and 27 squash players. The "Edinburgh Inventory Hand Preference Survey" was used as a data collection tool to determine the hand preferences of the athletes. In the determination of sports injuries suffered by athletes, the Cornell Musculoskeletal Discomfort Questionnaire was administered. There are significant differences between the lefty and righty athletes in terms of injuries in the left shoulder, left wrist and right lower leg regions when the injury regions in racket sports are compared by hand preferences (p<0.05). It is seen that the injuries that occur in right forearm, left wrist and the right upper leg regions of the athletes of racket sports differ according to branches (p<0.05). When the injury regions are examined according to hand preferences, it is seen that the injuries in the left shoulder, left wrist and lower right leg regions occur more in lefty athletes in comparison to righty athletes. When the relationship between the injury region regions and sports branches is examined, it can be argued that table tennis players suffer more frequent injuries in the left wrist compared to the players of other branches.

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Brumann, Christopher, Markus Kukuk, and Claus Reinsberger. "Evaluation of Open-Source and Pre-Trained Deep Convolutional Neural Networks Suitable for Player Detection and Motion Analysis in Squash." Sensors 21, no. 13 (July 2, 2021): 4550. http://dx.doi.org/10.3390/s21134550.

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In sport science, athlete tracking and motion analysis are essential for monitoring and optimizing training programs, with the goal of increasing success in competition and preventing injury. At present, contact-free, camera-based, multi-athlete detection and tracking have become a reality, mainly due to the advances in machine learning regarding computer vision and, specifically, advances in artificial convolutional neural networks (CNN), used for human pose estimation (HPE-CNN) in image sequences. Sport science in general, as well as coaches and athletes in particular, would greatly benefit from HPE-CNN-based tracking, but the sheer amount of HPE-CNNs available, as well as their complexity, pose a hurdle to the adoption of this new technology. It is unclear how many HPE-CNNs which are available at present are ready to use in out-of-the-box inference to squash, to what extent they allow motion analysis and if detections can easily be used to provide insight to coaches and athletes. Therefore, we conducted a systematic investigation of more than 250 HPE-CNNs. After applying our selection criteria of open-source, pre-trained, state-of-the-art and ready-to-use, five variants of three HPE-CNNs remained, and were evaluated in the context of motion analysis for the racket sport of squash. Specifically, we are interested in detecting player’s feet in videos from a single camera and investigated the detection accuracy of all HPE-CNNs. To that end, we created a ground-truth dataset from publicly available squash videos by developing our own annotation tool and manually labeling frames and events. We present heatmaps, which depict the court floor using a color scale and highlight areas according to the relative time for which a player occupied that location during matchplay. These are used to provide insight into detections. Finally, we created a decision flow chart to help sport scientists, coaches and athletes to decide which HPE-CNN is best for player detection and tracking in a given application scenario.

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Sugimoto, Norikazu, Masahiko Haruno, Kenji Doya, and Mitsuo Kawato. "MOSAIC for Multiple-Reward Environments." Neural Computation 24, no. 3 (March 2012): 577–606. http://dx.doi.org/10.1162/neco_a_00246.

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Reinforcement learning (RL) can provide a basic framework for autonomous robots to learn to control and maximize future cumulative rewards in complex environments. To achieve high performance, RL controllers must consider the complex external dynamics for movements and task (reward function) and optimize control commands. For example, a robot playing tennis and squash needs to cope with the different dynamics of a tennis or squash racket and such dynamic environmental factors as the wind. In addition, this robot has to tailor its tactics simultaneously under the rules of either game. This double complexity of the external dynamics and reward function sometimes becomes more complex when both the multiple dynamics and multiple reward functions switch implicitly, as in the situation of a real (multi-agent) game of tennis where one player cannot observe the intention of her opponents or her partner. The robot must consider its opponent's and its partner's unobservable behavioral goals (reward function). In this article, we address how an RL agent should be designed to handle such double complexity of dynamics and reward. We have previously proposed modular selection and identification for control (MOSAIC) to cope with nonstationary dynamics where appropriate controllers are selected and learned among many candidates based on the error of its paired dynamics predictor: the forward model. Here we extend this framework for RL and propose MOSAIC-MR architecture. It resembles MOSAIC in spirit and selects and learns an appropriate RL controller based on the RL controller's TD error using the errors of the dynamics (the forward model) and the reward predictors. Furthermore, unlike other MOSAIC variants for RL, RL controllers are not a priori paired with the fixed predictors of dynamics and rewards. The simulation results demonstrate that MOSAIC-MR outperforms other counterparts because of this flexible association ability among RL controllers, forward models, and reward predictors.

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Kawamoto, Yuta, Yoichi Iino, Shinsuke Yoshioka, and Senshi Fukashiro. "Directionally compensated mechanical work provided by the shoulder leads to similar racket velocities during open and square stance forehand groundstrokes in tennis." European Journal of Sport Science 19, no. 7 (December 14, 2018): 902–12. http://dx.doi.org/10.1080/17461391.2018.1552720.

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13

Chun Park, Byung. "Performance of automated storage/retrieval systems with non-square-in-time racks and two-class storage." International Journal of Production Research 44, no. 6 (March 15, 2006): 1107–23. http://dx.doi.org/10.1080/00207540500357070.

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14

Bachiller, David. "Solutions of the Yang–Baxter equation associated to skew left braces, with applications to racks." Journal of Knot Theory and Its Ramifications 27, no. 08 (July 2018): 1850055. http://dx.doi.org/10.1142/s0218216518500554.

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Given a skew left brace [Formula: see text], a method is given to construct all the non-degenerate set-theoretic solutions [Formula: see text] of the Yang–Baxter equation such that the associated permutation group [Formula: see text] is isomorphic, as a skew left brace, to [Formula: see text]. This method depends entirely on the brace structure of [Formula: see text]. We then adapt this method to show how to construct solutions with additional properties, like square-free, involutive or irretractable solutions. Using this result, it is even possible to recover racks from their permutation group.

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15

R.N. Palomar, P. Jensen, and V.K. Sulc. "EXPOSURE TESTS OF SURFACE TREATED SAWN COCONUT TIMBER." CORD 5, no. 01 (June 1, 1989): 34. http://dx.doi.org/10.37833/cord.v5i01.224.

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An investigation was made to determine the relative performance of three readily available inorganic chemicals containing either copper or chromium when applied singly or in combination to sawn coconut timber surfaces. The treating solutions, consisting of chromic acid (H2CrO4) sodium chromate (Na2CrO4) and copper sulphate (CuSO4), were applied by trush to wood surfaces with one coating at the rate of approximately 155 grams per square meter. The specimens were exposed outdoors on racks inclined at 450 angle and facing south. Results after 3 years of test showed that treatments with mixture of H2CrO4 and CuSO4 or combination of Na2CrO4 and CO4 performed better than single application of either H2Cr4 or Na2CrO4. The former treatments still showed uniform and pleasing appearance after the exposure period.

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G. Rintaugu, Elijah, Edna K. Thangu, Adewale Oyeyemi, and Makama A. Monyeki. "Sexual Behavioral Patterns of Kenyan University Student-Athletes: Implications for Sports Managers." Baltic Journal of Sport and Health Sciences 3, no. 118 (November 27, 2020): 33–42. http://dx.doi.org/10.33607/bjshs.v3i118.962.

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Background. The debate on whether participation in sports enhances or curtails risky sexual behavior among athletes continues. The purpose of the study was to establish the sexual behavior patterns and associated high risks among University student-athletes. Methods. A cross-sectional survey research design was used to collect self-report data on sexual behaviors from university student-athletes (n = 151) who participated in a University sports tournament. Descriptive statistics of frequencies and proportions and inferential statistics of chi-square test of independent measures were used to analyze the data. Majority (65%) of the student-athletes were taking part in Ball games and Racket games (13.9%). Results. About a third (33%) of the student-athletes had their first sexual debut while aged between 18 and 20 years, 60% had regular sexual partners, over 30% had more than one sexual partner and 67% would have sexual intercourse with strangers; only 58% of these would seek the sexual history of the strangers. More than half (55%) of the student-athletes frequently used condoms to prevent pregnancies and sexually transmitted diseases, but only 39% of them always used condoms with their sexual partners in the last six months. The participants’ sexual behaviors differed significantly (p < .05) by their gender. Males tended to start having sexual intercourse earlier (p < .002), had more than one sexual partner (p < 0.001) and would always use condoms (p < .001) than females, but more females than males would have sexual intercourse with a stranger (p < .001). Conclusions. Kenyan University student-athletes are sexually active and are faced with high risk sexual behaviors like multiple sexual partners and sexual intercourse with strangers. The difference in patterns of sexual behavior between male and female student-athletes calls for gender specific interventions by programmers, policy makers and health workers. Keywords: sexual behaviors, student-athletes, sexually transmitted diseases (STD’s).

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17

Lyu, Zhi-Jun, PeiCai Zhao, Qi Lu, Qian Xiang, and HongLiang Li. "Prediction of the Bending Strength of Boltless Steel Connections in Storage Pallet Racks: An Integrated Experimental-FEM-SVM Methodology." Advances in Civil Engineering 2020 (October 22, 2020): 1–17. http://dx.doi.org/10.1155/2020/5109204.

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Due to many differences in the material, geometry, and assembly method of the commercially available beam-end-connectors in steel storage pallet racks (SPR), no common numerical model has been universally accepted to accurately predict the M–θ behavior of complex semirigid connections so far. Despite the fact that the finite element method (FEM) and physical experiment have been used to obtain the mechanical performance of beam-to-column connections (BCCs), those methods have the disadvantages of high computational complexity and test cost. Taking, for example, the boltless steel connections, this paper proposes a data-driven simulation model (DDSM) that combines the experimental test, FEM, and support vector machine (SVM) techniques to determine the bending strength of BCCs by means of data mining from the engineering database. First, a three-dimensional (3D) finite element (FE) model was generated and calibrated against the experimental results. Subsequently, the validated FE model was further extended to perform parametric analysis and enrich the engineering case base of structural characterization of BCCs. Based on the M–θ curve of the FE simulation, support vector machines (SVMs) were trained to predict the flexural rigidity of beam-to-column joints. The predictive power of the SVM algorithms is estimated by comparison with traditional ANN models via the root mean square error (RMSE), the mean absolute percentage error (MAPE), and the correlation coefficient R. The results obtained indicate that the SVM algorithms slightly outperform the ANN algorithms, although both of them are in good agreement with FEM and physical test. From the point of view of engineering application, DDM is able to provide much more effective help for structural engineers to make rapid decisions on steel members design.

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Zhang, Zitian, Michel Rod, and Farah Hosseinian. "A Comprehensive Review on Sustainable Industrial Vertical Farming Using Film Farming Technology." Sustainable Agriculture Research 10, no. 1 (December 23, 2020): 46. http://dx.doi.org/10.5539/sar.v10n1p46.

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Rapid population growth is expected to lead to the global population reaching 8.9 billion by 2050. In order to sustain such population growth, global food production must grow more than 70% by 2050. Arable land per capita, however, is on the decline. Vertical farming (VF) provides an enterprising solution to these concerns. VF utilizes stacked levels of growing racks and beds to maximize grow space per square foot of land and typically uses hydroponics to reduce water use. Similarly, film farming (FF) is a new agricultural technique developed in Japan for the soilless cultivation of crops while drastically reducing water use. FF has the potential to be integrated into VF systems to improve water use efficiency, and further improve food safety. This, however, relies on the possible improvements in yield and plant quality to increase sales volume and price to offset the added cost of FF. This review illustrates a cost-benefit analysis of a theoretical VF to show the yield increase and price point needed for FF integration to be viable as 27 247 kg (43.57%) and $9.67/kg (26.90%) respectively. This review also shows the benefits to yield and quality is enough for the integration to be viable.

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Špulerová, Kruse, Branduini, Centeri, Eiter, Ferrario, Gaillard, et al. "Past, Present and Future of Hay-making Structures in Europe." Sustainability 11, no. 20 (October 10, 2019): 5581. http://dx.doi.org/10.3390/su11205581.

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Hay-making structures are part of the agricultural landscape of meadows and pastures. Hay meadows are still used and found all over Europe, but their distribution patterns as well as their characteristics and regional features depend on geographical area, climate, culture, and intensity of agriculture. Intensively used hay meadows are the most dominant, using heavy machinery to store hay mostly as rounded or square bales. Traditional hay-making structures represent structures or constructions, used to quickly dry freshly cut fodder and to protect it from humidity. The ‘ancient’ forms of traditional hay-making structures are becoming a relic, due to mechanisation and the use of new technologies. Both the need for drying hay and the traditional methods for doing so were similar across Europe. Our study of hay-making structures focuses on their current state, their development and history, current use and cultural values in various European countries. Regarding the construction and use of hay-making structures, we have distinguished three different types, which correlate to natural and regional conditions: (1) temporary hay racks of various shapes; (2) hay barracks, a special type of shelters for storing hay and (3) different types of permanent construction and buildings for drying and storing hay. Hay-making structures have been mostly preserved in connection with traditional agricultural landscapes, and particularly in the more remote regions or where associated with strong cultural identity.

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Moniruzzaman, M., K. K. Saha, M. M. Rahman, and M. M. H. Oliver. "Effect of available solar irradiance on vertical farming in semi-open urban places." Journal of Science Technology and Environment Informatics 10, no. 2 (November 30, 2020): 717–26. http://dx.doi.org/10.18801/jstei.100220.72.

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Building a vertical farm in unused residential and commercial spaces is a challenge. It is particularly hard to decide upon a space where varying degrees of lighting conditions may prevail at different times of a day. This experiment was focused on how innovative micro-irrigation technology could be coupled with vertical farms. In this regard, three storied racks were designed to accommodate multiple one-feet-square tubs large enough to hold five Indian spinach (BARI Puishak- 2) plants at a time. Sandy loam soil was used for farming along with recommended doses of fertilizers. Different lighting conditions (2- 145 W/m2 average solar irradiance) were employed on the fifth floor of an urban building. Drip emitters were coupled in the system for irrigation. The management allowed deficit was kept to a maximum of 50% of the readily available moisture below the field capacity. The results suggested that drip irrigation systems provide higher water productivity (up to 31.82 kg/m3) compared to the in-field conditions when BARI Puishak-2 is grown in vertical farming. Water productivity of spinach was improved by optimized set-up of a drip irrigation system. The study also concluded that vertical farming is only suitable for indoor places where plenty of direct sunlight or diffused sunlight (not below 70 W/m2) is available. The economic analysis suggests that vertical farms under direct sunlight can be made profitable (BCR>1) in the long run.

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Dzhibilov, S. M., and L. R. Gulueva. "Advanced Technology for Improving Degraded Slopes in Mountainous and Foothill Zones." Agricultural Machinery and Technologies 15, no. 1 (March 24, 2021): 57–62. http://dx.doi.org/10.22314/2073-7599-2021-15-1-57-62.

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The authors presented the technology and mechanization means for the restoration of degraded mountain areas with slope steepness up to 15 degrees.(Research purpose) To determine the optimal distance between the springy racks of the chisel cultivator KCHG-2.4; to characterize the developed block-module of the multifunctional unit KCHG-2.4, which performed three operations after the slitting process: sowing grasses, applying mineral fertilizers and rolling the sown seeds and granular fertilizers into the soil; to determine the effectiveness of the developed agricultural practices that increased productivity and the environment-forming role of mountain phytocenoses.(Materials and methods). The tests were carried out in the mountainous zone of North Ossetia - Alania at an altitude of 1540 meters above sea level with slope steepness up to 15 degrees. The experimental area was divided into three replicates. Each replicate was 2.4 meters wide, 10 meters long, dividing stripes 1 meter, side stripes 2.4 meters. The total test area, located across the slope, was 184.2 square meters.(Results and discussion) The springy Väderstad strut of the KCG-2.4 unit was used to slit the mountain slopes. For overseeding, a three-component grass mixture of Phleum pratense L., Dactylis glomerata L. and Trifolium pratense L. was proposed at a seeding rate of 15 kilograms per hectare. When applying mineral fertilizers, the following composition was used (in the active ingredient): ammonium nitrate – 35 percent; superphosphate – 20; potash salt – 40 percent, in total 445 kilograms per hectare. An increase in dry aboveground mass of 3.02-4.19 tons per hectare and the accumulation of underground plant mass in the range of 1.84-12.62 tons per hectare were got, depending on the variant of the experiment.(Conclusions) The authors found out that, a higher yield was obtained with a distance between the slits of 1.5 meters for 3 years of observations. It was found that the use of the unit increased the collection of feed units from 0.81-1.68 to 4.06-4.98 thousand per hectare. Taking into account all costs, the cost of one feed unit was 8.76 rubles.

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"Carbon fiber rackets help you play better squash." Reinforced Plastics 60, no. 3 (May 2016): 113. http://dx.doi.org/10.1016/j.repl.2016.04.014.

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23

Williams, Benjamin K., Ross H. Sanders, Joong Hyun Ryu, Philip Graham-Smith, and Peter J. Sinclair. "Racket orientation angle differences between accurate and inaccurate squash shots, as determined by a racket embedded magnetic-inertial measurement unit." Sports Biomechanics, March 4, 2021, 1–13. http://dx.doi.org/10.1080/14763141.2021.1892175.

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Driban, Jeffrey B., Grace H. Lo, Mary B. Roberts, Matthew S. Harkey, Lena Schaefer, Ida K. Haugen, Stacy E. Smith, et al. "Sports with a Bat or Racket are Not Associated with Thumb-base Osteoarthritis." Journal of Athletic Training, August 17, 2021. http://dx.doi.org/10.4085/1062-6050-0208.21.

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ABSTRACT Context: Repetitive joint use is a risk factor for osteoarthritis, which is a leading cause of disability. Sports requiring a bat or racket to perform repetitive high-velocity impacts may increase the risk of thumb-base osteoarthritis. However, this hypothesis remains untested. Objective: To determine if a history of participation in racket or bat sports is associated with the prevalence of thumb-base osteoarthritis. Design: Descriptive epidemiology study. Setting: Osteoarthritis Initiative. Four clinical sites in the United States. Participants: We included men and women from the recruited from the community. Eligible participants had dominant hand radiographic readings, hand symptom assessments, and historical physical activity survey data. Main Outcome Measures: A history of exposure to racket or bat sports (baseball/softball, racquetball/squash, badminton, table tennis, tennis [doubles/singles]) was based on self-reported recall data covering 3 age ranges (12–18 years, 19–34 years, 35–49 years). Prevalent radiographic thumb-base osteoarthritis was defined as someone with Kellgren-Lawrence grade≥2 in the first carpometacarpal joint or scaphotrapezoidal joint at the OAI baseline visit. Symptomatic thumb-base osteoarthritis was defined as the presence of radiographic osteoarthritis and hand/finger symptoms. Results: In total, we included 2309 participants. Among 1049 men, 355 (34%) and 56 (5%) had radiographic or symptomatic thumb-base osteoarthritis, respectively; and among 1260 women, 535 (42%) and 170 (13%), respectively. After adjusting for age, race, and education level, we found no statistically significant associations between a history of any racket or bat sport participation and thumb-base osteoarthritis (radiographic or symptomatic; odds ratios range from 0.82 to 1.34). Conclusions: Within a community-based cohort, a self-reported history of participation in racket or bat sports was not associated with an increased odds of having radiographic or symptomatic thumb-base osteoarthritis in the dominant hand.

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Plaut, R. H., A. D. Borum, and D. A. Dillard. "Analysis of Carbon Nanotubes and Graphene Nanoribbons With Folded Racket Shapes." Journal of Engineering Materials and Technology 134, no. 2 (March 27, 2012). http://dx.doi.org/10.1115/1.4006178.

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Folding of carbon nanotubes and graphene nanoribbons into a shape that looks like a tennis racket is considered. An elastic continuum model is utilized in two types of analysis. The first is called an “adhesion model,” in which the adjacent sides of the racket handle are assumed to be straight and bonded together with constant or no separation. The nanotube or nanoribbon is represented as an elastica. This model has been treated in the literature, but new analytical results are derived here, involving the geometry, work of adhesion, and bending and adhesion energies. Expressions are determined for (i) the length for which the total energy is the same as for the straight unstrained equilibrium configuration and (ii) for the minimum length for existence of a stable racket equilibrium shape. The second type of analysis uses the Lennard-Jones potential to model the attractive (van der Waals) and repulsive forces between the two sides of the racket. A nanoribbon is investigated, and the derivative of the interatomic potential is integrated along the length and across the width. Numerical solutions of the integro-differential equations are obtained with a new technique utilizing the finite difference method and minimization of the squares of the resulting algebraic equations. The results are presented for two cases with different flexural rigidities. The separation between the two sides of the handle decreases in the direction of the racket head (loop), and the handle experiences internal compression under the external attractive and repulsive forces. For the adhesion model, the dimensions of the head are proportional to the square root of the flexural rigidity, and this relationship is approximately satisfied in the numerical results based on the Lennard-Jones model.

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Samadiani, Emad, Yogendra Joshi, Hendrik Hamann, Madhusudan K. Iyengar, Steven Kamalsy, and James Lacey. "Reduced Order Thermal Modeling of Data Centers via Distributed Sensor Data." Journal of Heat Transfer 134, no. 4 (February 13, 2012). http://dx.doi.org/10.1115/1.4004011.

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In this paper, an effective and computationally efficient proper orthogonal decomposition (POD) based reduced order modeling approach is presented, which utilizes selected sets of observed thermal sensor data inside the data centers to help predict the data center temperature field as a function of the air flow rates of computer room air conditioning (CRAC) units. The approach is demonstrated through application to an operational data center of 102.2 m2 (1100 square feet) with a hot and cold aisle arrangement of racks cooled by one CRAC unit. While the thermal data throughout the facility can be collected in about 30 min using a 3D temperature mapping tool, the POD method is able to generate temperature field throughout the data center in less than 2 s on a high end desktop personal computer (PC). Comparing the obtained POD temperature fields with the experimentally measured data for two different values of CRAC flow rates shows that the method can predict the temperature field with the average error of 0.68 °C or 3.2%. The maximum local error is around 8 °C, but the total number of points where the local error is larger than 1 °C, is only ∼6% of the total domain points.

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Schmidt, Roger, Madhusudan Iyengar, and Joe Caricari. "Data Center Housing High Performance Supercomputer Cluster: Above Floor Thermal Measurements Compared To CFD Analysis." Journal of Electronic Packaging 132, no. 2 (June 1, 2010). http://dx.doi.org/10.1115/1.4001871.

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With the ever increasing heat dissipated by information technology (IT) equipment housed in data centers, it is becoming more important to project the changes that can occur in the data center as the newer higher powered hardware is installed. The computational fluid dynamics (CFD) software that is available has improved over the years. CFD software specific to data center thermal analysis has also been developed. This has improved the time lines of providing some quick analysis of the effects of new hardware into the data center. But it is critically important that this software provide a good report to the user of the effects of adding this new hardware. It is the purpose of this paper to examine a large cluster installation and compare the CFD analysis with environmental measurements obtained from the same site. This paper shows measurements and CFD data for high powered racks as high as 27 kW clustered such that heat fluxes in some regions of the data center exceeded 700 W per square foot. This paper describes the thermal profile of a high performance computing cluster located in an data center and a comparison of that cluster modeled via CFD. The high performance advanced simulation and computing (ASC) cluster had a peak performance of 77.8 TFlop/s, and employed more than 12,000 processors, 50 Tbytes of memory, and 2 Pbytes of globally accessible disk space. The cluster was first tested in the manufacturer’s development laboratory in Poughkeepsie, New York, and then shipped to Lawrence Livermore National Laboratory in Livermore, California, where it was installed to support the national security mission of the U.S. Detailed measurements were taken in both data centers and were previously reported. The Poughkeepsie results will be reported here along with a comparison to CFD modeling results. In some areas of the Poughkeepsie data center, there were regions that did exceed the equipment inlet air temperature specifications by a significant amount. These areas will be highlighted and reasons given on why these areas failed to meet the criteria. The modeling results by region showed trends that compared somewhat favorably but some rack thermal profiles deviated quite significantly from measurements.

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Journal articles on the topic 'Squash rackets'

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