Bench Height Research Articles

Equipment Selection Optimization System of Draglines and it’s Applications in Opencast Coalmine in China

Draglines equipment selection optimization involves many factors. Manual simulation has many shortcomings,such as lower calculation accuracy, less programs, long design cycle, so it is hard to make a optimization program. Equipment Selection Optimization System of Draglines (ESOSD) is designed and developed according to the deposit occurrence of opencast coalmines in China. Visual Basic 6.0 is used as programming language, Access 2003 as Background database and the software such as Microsoft Excel 2003 and Autodesk AutoCAD 2004 are integrated in the ESOSD. Three mining schemes of SL opencast coalmine that put forward by SY Design and Research Institute were optimized by using ESOSD. The results show that scheme Ⅱ is better than the other two schemes, which is recommended as the draglines stripping scheme. The main parameters of scheme Ⅱ are as follows: stripping bench height is 45 meters; stripping bench width is 60 meters; throwing blast is adopted; stripping bench is 16 meters lowered by two D10R580HP dozers; dragline model is 1570WS, which boom length is 91.7 meters and bucket capacity is 72.7 cubic meters, and annual overburden amount is 17.2 Million cubic meters. By comprehensive comparison the optimization results with that of SY Design and Research Institute, The total cost reduces 7.512 Million Yuan (RMB) than that of the institute, bucket capacity of dragline reduces 10.7 cubic meters, and boom length reduces 14.3 meters. The optimization results show that ESOSD is reliable and practical, and it can be used as a decision support system for draglines equipment selection optimization.

Bench Height And Step Cadence Effects In Aerobic Dance On Force Impact And Metabolic Cost

PURPOSE: Bench step aerobic (BSA) exercise has been shown to help individuals meet the ACSM recommendations for physical activity through the improvement of body composition, and aerobic capacity in a wide variety of populations. The purpose of this investigation was twofold: to (1) determine the acute metabolic and cardiorespiratory responses of simple bench step aerobics at two cadences (128 and 134 beats·min-1) and two bench heights (6 and 10 inches), and (2) calculate the average vertical ground reaction force (VGRF) and time to peak (TPEAK) at these cadences and bench heights. METHODS: Twelve subjects reported to the exercise physiology lab three times: (1) prescreening and maximum treadmill testing, (2) two of the four conditions, and (3) the remaining two conditions. Forty-eight hours rest was allowed after the maximal treadmill test and at least twenty-four hours rest between each lab visit before subjecting individuals to the various experimental conditions. At least fifteen minutes was allotted between exercise conditions within each lab visit with the order of testing randomized. The effects of stepping cadences and bench heights on the averages of HR, VO2, RER, caloric expenditure (kcal·min-1), VGRF, and TPEAK were determined using separate 2 × 2 analysis of variance (ANOVA) with repeated measures. RESULTS: There were significant differences between bench height and cadence for all dependent variables (TPEAK, KCAL, and VGRF). No significant interactions were found for any dependent variables. Caloric expenditure increased from of 6.85 ± 1.36 kcal·min-1 to 8.15 ± 1.97 kcal·min-1 for the 6 and 10 inch bench heights, respectively. Impact force increased from 1.62 ±.18 BW to 1.96 ±.23 BW for the 6 and 10 inch bench heights, respectively. CONCLUSIONS: Bench step aerobics is an effective, low-intensity aerobic activity. Intensity modifications may be made through both the cadence of the music and bench height. However, additional research is necessary to determine each individual's threshold for beneficial training adaptations and increased injury risk.

Maximum consumption of oxygen in step test: a longitudinal study in students of the Preparatory Nucleus of Reservation Officials

Introduction: The aim of this study is to measure the VO 2max in ascent and descent step test, in three moments, dur- ing the preparatory course for offi cials of the reservation. Materials and Methods: It's an applied, longitudinal, analytical, and probabilistic research. The sample consisted of 15 active men, average of age 18.7±0.5 years old. The stature, body mass, heart frequency (HF) of effort were measured and the phases, increment of the bench's height, number of touches per minute, ascent and descent rhythm of the ergometric bench and time of execution were controlled. The individuals used a cardiofrequencimeter of the brand Polar A5 in the gauging of HF and the Table of Borg in the subjective control of effort. The ergometric test applied was Cirilo's Electronic Bench Test, in three different moments. The used statistics was descriptive of average, standard deviation, maximum and minimum and inferential, using the Friedman's test for repeated measures. The signifi cance level was p<0.05 and the used software was the SPSS version 16. Results: In the fi rst moment, a mean of VO 2max of 38.34±1.68ml.kg -1 .min -1 was obtained, in the second 38.60±0.68ml.kg -1 .min -1 and in the third 39.96±1.74ml.kg -1 .min -1 , with signifi cant differences (p=0.004). Discussion: The level of cardiorespiratory capacity was classifi ed as reasonable, in the three moments of the test, by the index of VO 2max . This situation was not characterized in a satisfactory way for the specifi c needs of the troop during the investigated period, in comparison with the levels of this capacity in other studies with military.

Study on Dragline-Bulldozer Operation with Variations in Coal Seam Thickness

Abstract The dragline is one of the most promising surface mining machines in China. This paper studies the interaction between the working bench advancing speed and the stripping volume with variation in coal seam thickness. Adjusting the bulldozing volume (depth) and/or changing the dragline bench height are proposed as means to ensure a smooth and economical mining operation. When the coal seam is getting thicker it is recommended to reduce the bulldozing volume (depth) for a higher dragline efficiency. When the coal seam is getting thinner it is recommended to increase the bulldozing volume (depth) to ensure the dragline can work at the proper bench height.

Evolution of effective charge weight per delay for prediction of ground vibrations generated from blasting in a limestone mine

A major concern when blasting at surface mines is the generation of ground vibrations and air blasts and their effects on nearby structures. The current accepted practice is to control the weight of explosive in a delay, say 8 ms. Uncertainties in vibration analysis from blasts can be attributed to the problem of determining the actual amount of explosive detonating within a specific time interval, and the number of holes effectively contributing to the resulting particle velocity. This paper describes the results of a systematic study carried out to investigate these effects. It involved a total of over 29 blasts, employing one-, two- and three-hole calibration studies, and regular production blasts. In the latter, the bench height varied from 5.5 – 9.5 m, and boreholes loaded with ANFO explosives were 100 mm and 160 mm in diameter. Six tri-axial vibration sensors were located on ground surface along a linear array from 50 – 750 m from the blast, to investigate the changes in amplitude, frequency and duration with distance. The study compares single-hole blast signatures with multi-hole ones, and provides guidelines on determining the ‘effective’ charge weight per delay in vibration analyses of such blasts.

Effects of Kayak Ergometer Training on Motor Performance in Paraplegics

The purpose of this study was to assess the effects of kayak ergometer training on functional tests performed in wheelchair by persons with spinal cord injury. Ten post-rehabilitated persons with thoracic spinal cord injury volunteered for the study and performed 30 sessions of kayak ergometer training during a 10-week period. The ergometer was modified with an additional balance demand in the medio-lateral direction. Before and after the training period the subjects performed functional tests in the wheelchair: Sit-and-reach tests (distance), mounting a platform, transfer to a bench (height), propelling the wheelchair: 5 m on the rear wheels; in a figure-8; 15 m on a level surface and 50 m on a 3 degrees inclined surface (time). Test-retests were performed for all tests before the training began. A written questionnaire was distributed to evaluate the subjective experiences of the training. The test-retest resulted in coefficient of variation of 1.3 - 4.6 %. There were significant improvements in sit-and-reach (14 %), mounting a platform (7 %), transfer to a bench (10 %), propelling on level (3 %), and inclined surface (6 %). Furthermore, the training, did not cause any shoulder pain or other problems. This, and the positive subjective experience expressed by the subjects after the training indicate that this type of training is a suitable activity for persons with thoracic spinal cord injury.

The Effects of Home-based Bench Step Exercise on Aerobic Capacity, Lower Extremity Power and Static Balance in Older Adults

‹Objective› To examine the effects of a twelve-week home-based bench step exercise program on aerobic capacity, lower extremity power and static balance in elderly subjects. ‹Methods› Thirty-eight elderly men and women participated in this study (age: 75±4 years, mean±SD). The subjects were randomly assigned, according to the area in which they resided, into either the exercise group (EG: 11 men, 8 women) or the control group (CG: 14 men, 5 women). The EG performed a 12-week home-based bench step exercise program (7 sessions/week, 20-30 minutes/session, bench height 15.0-20cm). They recorded the length of exercise and their physical condition. Before and after the intervention a sub-maximum bench step test, a leg extension power test and a one-leg balance test with eyes open (balance test) were performed to assess the subjects' aerobic capacity, as determined by the lactate threshold (LT), as well as lower extremity power and static balance ability. ‹Results› The LT (3.9 (3.2, 4.9) vs. 5.4 (4.8, 5.6) METs; p<0.01) and leg extension power (7.1 (6.2, 9.9) vs. 10.3 (7.2, 13.7)watts/kg; p<0.05) significantly increased while the balance test (9 (4, 25) vs. 16 (6, 35)) sec; p<0.1) also tended to increase in the EG. Conversely, these parameters did not significantly change in the CG (4.5 (3.9, 5.1) vs. 4.9 (4.3, 5.5) METs; 7.4 (6.7, 12.5) vs. 8.1 (7.3, 12.5) watts/kg, 17 (8, 50) vs. 11 (6, 20) sec, neither N. S.) Based on the diary data, the subjects in the EG exercised an average of 164±56 minutes/week for twelve weeks. ‹Conclusion› This study showed that a bench step exercise program effectively improved not only aerobic capacity but also lower extremity power and static balance ability in elderly subjects.

Prediction of surface blast patterns in limestone quarries using artificial neural networks

This paper is an application of artificial neural networks (ANNs) in the prediction of the geometry of surface blast patterns in limestone quarries. The built model uses 11 input parameters which affect the design of the pattern. These parameters are: formation dip, blasthole diameter, blasthole inclination, bench height, initiation system, specific gravity of the rock, compressive and tensile strength, Young's modulus, specific energy of the explosive and the average resulting fragmentation size. Detailed data from a previous investigation were used to train and verify the network and predict burden and spacing of a blast. The built model was used to conduct parametric studies to show the effect of blasthole diameter and bench height on pattern geometry.

A new approach in blast vibration analysis and prediction at iron ore mines

Uncertainties in vibration analysis from blasts can be attributed to the problem of determining the actual amount of explosive detonating within a specific time interval, and the number of holes effectively contributing to the resulting particle velocity. This paper describes the results of a systematic study carried out to investigate these effects at iron ore mines in India. It involved a total of over 42 blasts, employing one-, two- and three-hole calibration studies, and regular production blasts. In the latter, the bench height varied from 6 m to 14 m, and boreholes loaded with ANFO and Emulsion explosives were 100 mm and 160 mm in diameter. The in-the-hole velocity of detonation of explosives was monitored. Six tri-axial vibration sensors were located on ground surface along a linear array from 25 m to 1·54 km from the blast sites, to investigate the changes in amplitude, frequency, and duration with distance. Responses of various structures (including one- and two-story homes) to blast vibration were taken to investigate the impact of blast wave frequencies on vibration level on the structures. The study compares single-hole blast signatures with multi-hole ones, and provides guidelines on determining the 'effective' charge-weight in vibration analysis of such blasts. Optimum delay intervals between two detonations have been recommended to control vibrations and their impact on the structures.

Calculated scheme of rock lump splitting off under the impact of wedge beneath a bench

A calculated model is developed for propagation of a crack under the impact of wedge beneath a bench. Basing on the model, a single-impact energy required to split off a lump is estimated depending on the bench height, characteristics of rock, and parameters of an instrument.

Effect of bench height on sit-to-stand in children without disabilities and children with cerebral palsy

Hennington G, Johnson J, Penrose J, Barr K, McMulkin ML, Vander Linden DW. Effect of bench height on sit-to-stand in children without disabilities and children with cerebral palsy. Arch Phys Med Rehabil 2004;85:70–6. Objective To evaluate the effect of seat height on sit-to-stand (STS) in children with cerebral palsy (CP) and in children without disabilities. Design A mixed design (subject type by seat height) with repeated measures for seat height. Setting Motion analysis laboratory. Participants Ten children with mild CP (mean age, 10.9±2.7y) and 10 children without disabilities (mean age, 8.7±2.4y). Interventions Kinematic and force measurements of STS were completed with 6 infrared cameras and 2 forceplates. Main outcome measures Phase duration of the STS movement, amplitude and timing of ground reaction forces, and maximum head velocity during the movement. Results Children with CP took significantly longer to rise to standing (1.71s) than children without disabilities (1.24s) (F 1,18=16.97). The extension phase of STS was also significantly longer for children with CP (.85s) than for children without disabilities (.45s) (F 1,18=18.73). Seat height did not affect time to stand for either children with CP or children without disabilities (F 1,18=2.82, P>.05). The duration of the extension phase, maximum horizontal and vertical velocity of the head, and maximum vertical ground reaction force were all significantly greater when children stood from the low bench height than from the higher bench height, although we found no significant differences by subject type for maximum horizontal and vertical head velocity or for maximum vertical ground reaction force. Conclusions Although children with CP were able to modify their motor programs for STS to accommodate changes in seat height as readily as nondisabled children, the speed with which they extended against gravity was slower; therefore, the total STS movement took longer for them to complete than for children without disabilities. Because the time to complete STS from the low and high bench did not differ, it would appear that time to ascend from sitting may be invariant and therefore be a motor control parameter for the STS movement.

Metabolic Cost of Aerobic Dance Bench Stepping at Varying Cadences and Bench Heights

To determine the metabolic and cardiovascular responses of aerobic dance bench stepping (ADBS) at commonly used cadences and bench heights, 30 women (19–47 years of age) performed a graded maximal treadmill test and four 8-minute submaximal ADBS routines. Subjects followed identical videotape sequences of basic ADBS movements at cadences of 125 and 130 beats·min-1 at bench heights of 6 and 8 in. Physiological measurements were taken during each minute of each test. Mean values calculated from the last 3 minutes were used for data analysis. Although there were no physiological differences between ADBS at the 2 cadences, there were significant physiological differences between ADBS at the 2 bench heights. On average, a 2-in. increase in bench height, increased heart rate, Vo2, and rating of perceived exertion by 10 beats·min-1, 3.09 ml·kg-1 min-1, and 1.53, respectively. In conclusion, it appears that bench height is more of a factor than cadence in increasing metabolic cost of ADBS. Results from this study provide information about the energy cost of ADBS at the common bench heights and cadences used in this study and, therefore, may be used to help aerobic participants select the proper bench height and cadence combination to control body weight and develop cardiorespiratory fitness safely and effectively.

Metabolic Cost of Aerobic Dance Bench Stepping at Varying Cadences and Bench Heights

To determine the metabolic and cardiovascular responses of aerobic dance bench stepping (ADBS) at commonly used cadences and bench heights, 30 women (19-47 years of age) performed a graded maximal treadmill test and four 8-minute submaximal ADBS routines. Subjects followed identical videotape sequences of basic ADBS movements at cadences of 125 and 130 beats.min(-1) at bench heights of 6 and 8 in. Physiological measurements were taken during each minute of each test. Mean values calculated from the last 3 minutes were used for data analysis. Although there were no physiological differences between ADBS at the 2 cadences, there were significant physiological differences between ADBS at the 2 bench heights. On average, a 2-in. increase in bench height, increased heart rate, VO2, and rating of perceived exertion by 10 beats.min(-1), 3.09 ml.kg(-1) min(-1), and 1.53, respectively. In conclusion, it appears that bench height is more of a factor than cadence in increasing metabolic cost of ADBS. Results from this study provide information about the energy cost of ADBS at the common bench heights and cadences used in this study and, therefore, may be used to help aerobic participants select the proper bench height and cadence combination to control body weight and develop cardiorespiratory fitness safely and effectively.

METABOLIC COST OF AEROBIC DANCE BENCH STEPPING AT VARYING CADENCES AND BENCH HEIGHTS

To determine the metabolic and cardiovascular responses of aerobic dance bench stepping (ADBS) at commonly used cadences and bench heights, 30 women (19-47 years of age) performed a graded maximal treadmill test and four 8-minute submaximal ADBS routines. Subjects followed identical videotape sequences of basic ADBS movements at cadences of 125 and 130 beats.min(-1) at bench heights of 6 and 8 in. Physiological measurements were taken during each minute of each test. Mean values calculated from the last 3 minutes were used for data analysis. Although there were no physiological differences between ADBS at the 2 cadences, there were significant physiological differences between ADBS at the 2 bench heights. On average, a 2-in. increase in bench height, increased heart rate, VO2, and rating of perceived exertion by 10 beats.min(-1), 3.09 ml.kg(-1) min(-1), and 1.53, respectively. In conclusion, it appears that bench height is more of a factor than cadence in increasing metabolic cost of ADBS. Results from this study provide information about the energy cost of ADBS at the common bench heights and cadences used in this study and, therefore, may be used to help aerobic participants select the proper bench height and cadence combination to control body weight and develop cardiorespiratory fitness safely and effectively.

A Practical Approach for Open Pit Design and Visualisation

Mineral Resources EngineeringVol. 09, No. 03, pp. 313-321 (2000) No AccessA PRACTICAL APPROACH FOR OPEN PIT DESIGN AND VISUALISATIONKAAN ERARSLANKAAN ERARSLANDepartment of Mining Engineering, Dumlupinar University, 43100, Kütahya, Turkey Search for more papers by this author https://doi.org/10.1142/S0950609800000238Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractIn this study, a practical and simple system for design and visualisation of open pits has been developed. The developed mathematical model and visualisation technique have been presented in details. A set of co-ordinates on polygon of pit bottom is used to expand the pit with a certain slope angle, bench height and width. Co-ordinates of each expanded toe and crest point are calculated by the system, which are derived from the node points on the pit bottom polygon. Each co-ordinate is stated by east, north and elevation co-ordinates. After completing the geometric calculation of node co-ordinates, the system generates the pit model for visualisation. This familiar expansion method is integrated with a drawing approach called DXF format, which reduces visualisation of pit to co-ordinate calculation and eliminates processes for computer graphics. Calculated co-ordinates are employed to generate the DXF form of the pit model. Resulting DXF form can be processed in any DXF processing system by which the drawing can be applied to any utilities provided. Rotation, rendering are examples for the most used utilities. Picture quality drawings can be obtained by the developed system. The geometric algorithm has been coded in C++ and applied to example data. The results have revealed the validity, applicability and practicability of the developed system. FiguresReferencesRelatedDetails Recommended Vol. 09, No. 03 Metrics History PDF download

A PRACTICAL APPROACH FOR OPEN PIT DESIGN AND VISUALISATION

Mineral Resources EngineeringVol. 09, No. 03, pp. 313-321 (2000) No AccessA PRACTICAL APPROACH FOR OPEN PIT DESIGN AND VISUALISATIONKAAN ERARSLANKAAN ERARSLANDepartment of Mining Engineering, Dumlupinar University, 43100, Kütahya, Turkey Search for more papers by this author https://doi.org/10.1142/S0950609800000238Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractIn this study, a practical and simple system for design and visualisation of open pits has been developed. The developed mathematical model and visualisation technique have been presented in details. A set of co-ordinates on polygon of pit bottom is used to expand the pit with a certain slope angle, bench height and width. Co-ordinates of each expanded toe and crest point are calculated by the system, which are derived from the node points on the pit bottom polygon. Each co-ordinate is stated by east, north and elevation co-ordinates. After completing the geometric calculation of node co-ordinates, the system generates the pit model for visualisation. This familiar expansion method is integrated with a drawing approach called DXF format, which reduces visualisation of pit to co-ordinate calculation and eliminates processes for computer graphics. Calculated co-ordinates are employed to generate the DXF form of the pit model. Resulting DXF form can be processed in any DXF processing system by which the drawing can be applied to any utilities provided. Rotation, rendering are examples for the most used utilities. Picture quality drawings can be obtained by the developed system. The geometric algorithm has been coded in C++ and applied to example data. The results have revealed the validity, applicability and practicability of the developed system. FiguresReferencesRelatedDetails Recommended Vol. 09, No. 03 Metrics History PDF download

Selection of blasthole diameter for a given bench height at surface mines

Selection of blasthole diameter for a given bench height at surface mines

KINETIC ANALYSIS OF BENCH STEPPING: WHAT ARE THE EFFECTS OF BENCH HEIGHT AND MUSIC TEMPO?

440 The purpose of this research was to determine if variations in bench height and music tempo affect kinetic parameters in the step-down phase of bench step aerobics. Twenty experienced females (26.95 years) volunteered to participate. Each subject performed 27 randomly ordered trials containing combinations of the three bench heights (6, 8, 10 inches) and three music tempos (120, 130, 140 beats per minute). Data were collected with an AMTI force platform. Data were sampled at 500HZ and recorded for two seconds to capture the step-down phase of the motion. A 3×3 factorial MANOVA (alpha of 0.05) design was used to evaluate the kinetic data with bench height and music tempo as independent variables and vertical, mediolateral and anteroposterior kinetic parameters as the dependent variables. Significant differences were found between all bench heights for peak vertical forces (p=0.000), peak vertical impulse (p=0.007), time-to-peak vertical force (p=0.000), and time-to-peak anteroposterior force (p=0.000). Significant differences were found between all music tempos for peak vertical impulse (p=0.008), time-to-peak vertical force (p=0.000), and time-to-peak anteroposterior force (p=0.018). The kinetic trends reflected greater magnitudes as bench height and music tempo increased while time-to-peak kinetic parameters decreased. It was concluded that the potential for musculoskeletal injury due to repetitive bouts of bench stepping activity may increase as bench height and music tempo increase.

A Statistical Analysis of Fragmentation After Single Hole Bench Blasting

The purpose of this study is to statistically correlate the fragmentation gradient (\(\)) and average fragment size (\(\)) with the blasting test parameters for rock masses having different characteristics. Blasting tests were conducted in limestone exposed during the highway construction between Tarsus and Pozanti (Turkey). Three test sites were classified as poor rock, good rock, and very good rock according to their RMR ratings. The selected blasting test parameters that affect the degree of fragmentation were burden, bench height and ANFO charge. After each blast, the muckpiles were screened and fragment size distribution graphs were plotted. Yates' method was applied for experimental design and analysis of variance. The single and combined effects of blasting test parameters were analyzed through the Yates' tables and significant and non-significant treatment combinations were determined for different rock masses. Some conclusions drawn from this research are: 1. The increase of RMR ratings promotes fragmentation, hence, increases blasting efficiency. 2. In rock masses of low RMR ratings, the volume of broken material is large, but fragmentation into small sizes is low. The opposite is true for rock masses of high RMR ratings. 3. The length of charge column is the significant factor affecting the average fragment size regardless the type of rock mass and is more significant in very good quality rock mass.

A modified step test based on a function of subjects' stature.

A number of submaximal step tests have been developed to predict maximal aerobic capacity. Because step height may influence biomechanical efficiency and heart rate, step tests based on subjects' stature may more accurately predict maximal aerobic capacity. Eighteen women performed the Queens College step test and a modified Queens College step test. The modified step test was performed with the height of the bench set even with the height of the foot at a knee angle of 90 degrees. Analysis of the data indicated a lower recovery heart rate following this test (p < .05). Further, correlations between maximal aerobic capacity and recovery heart rate for both tests were moderate (r = -.80 and -.75, respectively). Our results suggest that step tests based on subjects' stature do not more accurately predict aerobic capacity than those using a standardized bench height.