To see the other types of publications on this topic, follow the link: Measurement centre of gravity height.
Journal articles on the topic 'Measurement centre of gravity height'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Measurement centre of gravity height.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Fabbri, A., and G. Molari. "Static Measurement of the Centre of Gravity Height on Narrow-track Agricultural Tractors." Biosystems Engineering 87, no. 3 (March 2004): 299–304. http://dx.doi.org/10.1016/j.biosystemseng.2003.12.008.
Full text
2
MacDonald, G. B., and R. R. Forslund. "Application of a geometrical volume equation to species with different bole forms." Canadian Journal of Forest Research 16, no. 2 (April 1, 1986): 311–14. http://dx.doi.org/10.1139/x86-052.
Full textAbstract:
Stem analysis of 20 Abiesbalsamea (L.) Mill., 68 Piceamariana (Mill.) B.S.P., 19 Piceaglauca (Moench) Voss, 31 Populustremuloides Michx., and 37 Betulapapyrifera Marsh. revealed form variation between species. A volume equation based on the paracone (a geometrical solid midway between a paraboloid and a cone) estimated individual tree volume within 10% of the true volume (at the 95% confidence level) for all species. The input variables required were total height and diameter at a relative height of 0.2 for Betulapapyrifera and 0.3 for the other four species. If breast-height diameter was used, the effect of form variation on the accuracy of volume prediction was more pronounced. In this case, the geometrical equation modified for each species according to the average centre of gravity provided more consistently accurate volume estimates than either the paracone equation or Honer's transformed variable equation. For all species, the diameter measurement position was more critical than the version of the geometrical equation selected.
3
Paiman, Noor Faradila, Akmalia Shabadin, Aqbal Hafeez Ariffin, Solah Mohd Syazwan, and Hamzan Azhar. "Child Motorcycle Pillion Rider Anthropometric Measurement." Applied Mechanics and Materials 663 (October 2014): 557–61. http://dx.doi.org/10.4028/www.scientific.net/amm.663.557.
Full textAbstract:
In Malaysia, wheremotorcycles are often used as a family vehicle, children tend to travel as pillion riders at an early age, most commonly sat in front of the rider, either on the fuel tank or in the carrying basket, or alternatively behind the rider. This study aims to determine the possible mismatches between individual lower limb dimensions of Malaysian primary students and motorcycle pillion seat. An anthropometric survey was carried out on a sample of male and female school children aged 7-9 years (N=233), to elucidate on the anthropometric parameters of Malaysian children. A set of seen body dimensions covering most of the lower extremity, relevant to the design of riding pillion on a motorcycle were considered. Additionally, an investigation of foot-foot peg gap and knee opening length on a static motorcycle test rig was also measured. There is a significant vertical difference between child pillion riders’ feet relative to motorcycle foot pegs. The maximum height of students who were not able to reach the foot pegs was 1263 mm with a mean of 1137 mm, which is similar with student volunteers’ age 7 years old (mean = 1160 mm). Stature influences the centre of gravity and stability of motorcycle, especially during cornering. This anthropometric analysis could be used to design ergonomic-oriented motorcycles which will not only suit the small stature of child pillion riders, but also improve the level of comfort.
4
Geller, Marvin A., M. Joan Alexander, Peter T. Love, Julio Bacmeister, Manfred Ern, Albert Hertzog, Elisa Manzini, et al. "A Comparison between Gravity Wave Momentum Fluxes in Observations and Climate Models." Journal of Climate 26, no. 17 (August 23, 2013): 6383–405. http://dx.doi.org/10.1175/jcli-d-12-00545.1.
Full textAbstract:
Abstract For the first time, a formal comparison is made between gravity wave momentum fluxes in models and those derived from observations. Although gravity waves occur over a wide range of spatial and temporal scales, the focus of this paper is on scales that are being parameterized in present climate models, sub-1000-km scales. Only observational methods that permit derivation of gravity wave momentum fluxes over large geographical areas are discussed, and these are from satellite temperature measurements, constant-density long-duration balloons, and high-vertical-resolution radiosonde data. The models discussed include two high-resolution models in which gravity waves are explicitly modeled, Kanto and the Community Atmosphere Model, version 5 (CAM5), and three climate models containing gravity wave parameterizations, MAECHAM5, Hadley Centre Global Environmental Model 3 (HadGEM3), and the Goddard Institute for Space Studies (GISS) model. Measurements generally show similar flux magnitudes as in models, except that the fluxes derived from satellite measurements fall off more rapidly with height. This is likely due to limitations on the observable range of wavelengths, although other factors may contribute. When one accounts for this more rapid fall off, the geographical distribution of the fluxes from observations and models compare reasonably well, except for certain features that depend on the specification of the nonorographic gravity wave source functions in the climate models. For instance, both the observed fluxes and those in the high-resolution models are very small at summer high latitudes, but this is not the case for some of the climate models. This comparison between gravity wave fluxes from climate models, high-resolution models, and fluxes derived from observations indicates that such efforts offer a promising path toward improving specifications of gravity wave sources in climate models.
5
HALLWORTH, MARK A., HERBERT E. HUPPERT, and MARIUS UNGARISH. "Axisymmetric gravity currents in a rotating system: experimental and numerical investigations." Journal of Fluid Mechanics 447 (October 30, 2001): 1–29. http://dx.doi.org/10.1017/s0022112001005523.
Full textAbstract:
The propagation at high Reynolds number of a heavy, axisymmetric gravity current of given initial volume over a horizontal boundary is considered in both rotating and non-rotating situations. The investigation combines experiments with theoretical predictions by both shallow-water approximations and numerical solutions of the full axisymmetric equations. Attention is focused on cases when the initial ratio of Coriolis to inertia forces is small. The experiments were performed by quickly releasing a known cylindrical volume of dense salt water of 2 m diameter at the centre of a circular tank of diameter 13 m containing fresh ambient water of typical depth 80 cm. The propagation of the current was recorded for different initial values of the salt concentration, the volume of released fluid, the ratio of the initial height of the current to the ambient depth, and the rate of rotation. A major feature of the rotating currents was the attainment of a maximum radius of propagation. Thereafter a contraction–relaxation motion of the body of fluid and a regular series of outwardly propagating pulses was observed. The frequency of these pulses is slightly higher than inertial, and the amplitude is of the order of magnitude of half the maximum radius. Theoretical predictions of the corresponding gravity currents were also obtained by (i) previously developed shallow-water approximations (Ungarish & Huppert 1998) and (ii) a specially developed finite-difference code based on the full axisymmetric Navier–Stokes equations. The ‘numerical experiments’ provided by this code are needed to capture details of the flow field (such as the non-smooth shape of the interface, the vertical dependence of the velocity field) which are not reproduced by the shallow-water model and are very difficult for, or outside the range of, accurate experimental measurement. The comparisons and discussion provide insight into the flow field and indicate the advantages and limitations of the verified simulation tools.
6
Dachi, Reliusman, and Ikhsan Setiawan. "Measurement of gravitational acceleration with the leak tank method." Journal of Physics: Theories and Applications 2, no. 1 (March 31, 2018): 19. http://dx.doi.org/10.20961/jphystheor-appl.v2i1.29000.
Full textAbstract:
<p class="Abstract">An experimental device of the mechanics of tank draining under gravity has been constructed. It mainly consists of a cylindrical tank with a circular orifice at the center bottom of the tank. The inner radius of the tank is 134 mm, while there are seven variations of orifice radius, those are 2.25 mm, 2.50 mm, 3.00 mm, 3.50 mm, 4.00 mm, 5.00 mm, and 6.00 mm. The tank is filled by water which is then allowed to flow out throuh the orifice. This experiment can be used to measure the value of gravitational acceleration () on the experiment location. We call this method as the leak tank method. The measurement of g is carried out by measuring the total time to drain the tank from 300 mm initial height of water surface inside the tank for various orifice radius. It is found in this experiment that = (9.89± 0.03) m/s<sup>2</sup>. This result is good enough because it is almost the same as the conventional standar value of 9.80665 m/s<sup>2</sup> with discrepancy of around 0.85%. It indicates that the leak tank method which is described in this paper can be used to estimate the gravitational acceleration value with a good result.</p>
7
MAXWORTHY, T., and R. I. NOKES. "Experiments on gravity currents propagating down slopes. Part 1. The release of a fixed volume of heavy fluid from an enclosed lock into an open channel." Journal of Fluid Mechanics 584 (July 25, 2007): 433–53. http://dx.doi.org/10.1017/s0022112007006702.
Full textAbstract:
Gravity currents formed by the release of heavy fluid from an enclosed lock on a sloping open channel were investigated experimentally. The experiments were conducted in a channel that had a running length of 13 lock depths, and could be inclined to a maximum angle of 17°. The release of heavy dyed salt solution from a lock with an aspect ratio (height to length) of 0.5, was examined using video images to determine the front velocity, and a particle-tracking technique was used to measure the two-dimensional velocity field in a vertical slice through the centre of the evolving current. The gravity current head velocity increased with time and downstream distance to a maximum at approximately 10 lock depths from the front of the lock. Flow visualization and the velocity measurements have shown that during the acceleration phase the head was being fed by a following current that increased its buoyancy as it propagated downstream. A modified version of the theory of P. Beghin, E. J. Hopfinger and R. E. Britter (J. Fluid Mech.vol. 107, 1981, p. 407) in which the measured increase in buoyancy was used, instead of the original assumption of constant buoyancy, gave results that agreed closely with the experimental velocity versus time histories.
8
Skrucany, Tomas, Jan Vrabel, and Patrik Kazimir. "The influence of the cargo weight and its position on the braking characteristics of light commercial vehicles." Open Engineering 10, no. 1 (February 27, 2020): 154–65. http://dx.doi.org/10.1515/eng-2020-0024.
Full textAbstract:
AbstractThe influence of the cargo weight loaded on the vehicle and the total gross mass of the vehicle on the braking characteristics is often researched from the road safety reason. However, there is not enough knowledge about the influence of weight and load distribution on the loading area of small trucks or vans on their braking characteristics. This article presents the results of measurements of braking decelerations of the van of N1 category and the braking characteristics of a vehicle loaded with different cargo mass with different cargo locations on the loading area. The impact of the longitudinal cargo position on the loading area on the load of the individual axles and thus on the braking deceleration of the vehicle was investigated. The influence of the height of the center of gravity on the dynamic axle load during braking was also determined. Method of direct vehicle deceleration measurement was used by a decelerometer. There were calculated cargo weight and cargo position influences on the dynamic axle load during braking according to the vehicle deceleration.
9
Piotr Fundowicz, Hubert Sar, and Mateusz Brukalski. "Estimation of Wheels' Normal Reaction Forces of Automobile in Steady-State Curvilinear Motion." Communications - Scientific letters of the University of Zilina 23, no. 4 (August 27, 2021): B317—B324. http://dx.doi.org/10.26552/com.c.2021.4.b317-b324.
Full textAbstract:
Computer simulation seems to be one of the cheapest and relatively fast methods of investigating vehicle motion. Thereby, it may be important in the case of calculations for the reconstruction of traffic incidents. In particular, that may be important to answer the following question: How wheels' normal reaction forces differ during the cornering of a vehicle?
In this article, the authors presented how the normal reaction forces vary in the case of roll motion of a vehicle body. Suitable mathematical equations are presented. Furthermore, the measurements of the height of the centre of gravity were performed, which was necessary to obtain the normal reaction forces while vehicle body rolls. The authors decided to apply dimensionless coefficients, which represented the properties of a front and rear suspension. Additionally, dimensionless parameters were applied to consider the impact of asymmetrical distribution of vehicle load on normal reaction forces of wheels on a road surface.
10
Charron, Martin, Saroja Polavarapu, Mark Buehner, P. A. Vaillancourt, Cécilien Charette, Michel Roch, Josée Morneau, et al. "The Stratospheric Extension of the Canadian Global Deterministic Medium-Range Weather Forecasting System and Its Impact on Tropospheric Forecasts." Monthly Weather Review 140, no. 6 (June 1, 2012): 1924–44. http://dx.doi.org/10.1175/mwr-d-11-00097.1.
Full textAbstract:
Abstract A new system that resolves the stratosphere was implemented for operational medium-range weather forecasts at the Canadian Meteorological Centre. The model lid was raised from 10 to 0.1 hPa, parameterization schemes for nonorographic gravity wave tendencies and methane oxidation were introduced, and a new radiation scheme was implemented. Because of the higher lid height of 0.1 hPa, new measurements between 10 and 0.1 hPa were also added. This new high-top system resulted not only in dramatically improved forecasts of the stratosphere, but also in large improvements in medium-range tropospheric forecast skill. Pairs of assimilation experiments reveal that most of the stratospheric and tropospheric forecast improvement is obtained without the extra observations in the upper stratosphere. However, these observations further improve forecasts in the winter hemisphere but not in the summer hemisphere. Pairs of forecast experiments were run in which initial conditions were the same for each experiment but the forecast model differed. The large improvements in stratospheric forecast skill are found to be due to the higher lid height of the new model. The new radiation scheme helps to improve tropospheric forecasts. However, the degree of improvement seen in tropospheric forecast skill could not be entirely explained with these purely forecast experiments. It is hypothesized that the cycling of a better model and assimilation provide improved initial conditions, which result in improved forecasts.
11
Stavrev, Petar, Daniela Gerovska, and Marcos J. Araúzo-Bravo. "Automatic inversion of magnetic anomalies from two height levels using finite-difference similarity transforms." GEOPHYSICS 71, no. 6 (November 2006): L75—L86. http://dx.doi.org/10.1190/1.2345192.
Full textAbstract:
We solve the inverse magnetic problem for the depth and shape of simple sources in the presence of a regional field and truly random noise. We do not use noise-generating derivatives nor are we forced to solve complex systems of equations. Our inverse operator applies a new geometric type of field transform, the finite-difference similarity transform (FDST), that is based on a postulated degree of homogeneity in the potential field. Magnetic data from two height levels are required for the calculation of the FDSTs. The FDSTs are generated for an assumed central point of similarity (CPS) and a trial value (index) for the coefficient of similarity, and they are sensitive to the distance between the source and the CPS and to the agreement between the index and the degree of homogeneity in the data. When the CPS converges to a singular point in the potential field, say, the center or the topedge of the source, and when the trial index converges on the degree of homogeneity present in the data, the FDST drops in amplitude and its plot approaches a straight line, thereby signaling an interpretation for the source position and type. All inverse operations are fully automated and applicable to the interpretation of large data sets. The necessary data for the second level can be obtained by actual measurement or, alternatively, by deriving them from the data at the first level by an upward, analytical continuation. Upward continuation suppresses high-wavenumber random noise and thus contributes to a stable inversion. Model tests show that a suitable height for the second level is less than the expected depth of the source below the first level, while a suitable window length is about twice that depth. Examples show that the proposed inversion is effective on both model and field data. Note that this approach can be extended to the inversion of any component or derivative of the 2D or 3D magnetic or gravity fields from simple sources.
12
Alberts, Jay L., Joshua R. Hirsch, Mandy Miller Koop, David D. Schindler, Daniel E. Kana, Susan M. Linder, Scott Campbell, and Anil K. Thota. "Using Accelerometer and Gyroscopic Measures to Quantify Postural Stability." Journal of Athletic Training 50, no. 6 (June 1, 2015): 578–88. http://dx.doi.org/10.4085/1062-6050-50.2.01.
Full textAbstract:
Context Force platforms and 3-dimensional motion-capture systems provide an accurate method of quantifying postural stability. Substantial cost, space, time to administer, and need for trained personnel limit widespread use of biomechanical techniques in the assessment of postural stability in clinical or field environments. Objective To determine whether accelerometer and gyroscope data sampled from a consumer electronics device (iPad2) provide sufficient resolution of center-of-gravity (COG) movements to accurately quantify postural stability in healthy young people. Design Controlled laboratory study. Setting Research laboratory in an academic medical center. Patients or Other Participants A total of 49 healthy individuals (age = 19.5 ± 3.1 years, height = 167.7 ± 13.2 cm, mass = 68.5 ± 17.5 kg). Intervention(s) Participants completed the NeuroCom Sensory Organization Test (SOT) with an iPad2 affixed at the sacral level. Main Outcome Measure(s) Primary outcomes were equilibrium scores from both systems and the time series of the angular displacement of the anteroposterior COG sway during each trial. A Bland-Altman assessment for agreement was used to compare equilibrium scores produced by the NeuroCom and iPad2 devices. Limits of agreement was defined as the mean bias (NeuroCom − iPad) ± 2 standard deviations. Mean absolute percentage error and median difference between the NeuroCom and iPad2 measurements were used to evaluate how closely the real-time COG sway measured by the 2 systems tracked each other. Results The limits between the 2 devices ranged from −0.5° to 0.5° in SOT condition 1 to −2.9° to 1.3° in SOT condition 5. The largest absolute value of the measurement error within the 95% confidence intervals for all conditions was 2.9°. The mean absolute percentage error analysis indicated that the iPad2 tracked NeuroCom COG with an average error ranging from 5.87% to 10.42% of the NeuroCom measurement across SOT conditions. Conclusions The iPad2 hardware provided data of sufficient precision and accuracy to quantify postural stability. Accuracy, portability, and affordability make using the iPad2 a reasonable approach for assessing postural stability in clinical and field environments.
13
Lam, Nicholas H. K., Wai Man Lau, and Tin Lap Lau. "Effects of a 6-week core stabilization training program on dynamic balance and trunk stabilization endurance of horse riders." Sport Sciences for Health 17, no. 3 (January 20, 2021): 655–64. http://dx.doi.org/10.1007/s11332-020-00729-0.
Full textAbstract:
AbstractThe purpose of this study was to examine the effectiveness of a 6-week core stabilization training program (CSTP) in improving dynamic balance and back-extensor endurance of horse riders; and develop a measurement tool in assessing the dynamic postural stabilization endurance for horse riders. Twelve male horse riders (age: 23.58 ± 1.93 years; height: 165.09 ± 4.60 cm; weight: 56.53 ± 4.75 kg; experience in horse racing: 1.75 ± 0.34 years) completed 12 training sessions in 6 weeks. Subjects performed the CSTP with two progressions. CSTP started with the basic consciousness activation exercises, and then eliminated visual feedback in dynamic balance task on unstable surfaces and finished with switching the center of gravity. Moderate-to-large difference was demonstrated in the Y-Balance test scores for right leg (102.81 ± 8.32 vs 106.471 ± 4.35 cm, d = 0.55, 95% CL 0.00 to 1.08) and left leg (102.04 ± 3.20 vs 106.29 ± 3.62 cm, d = 1.25, 95% CL 0.41 to 2.05) following 6 weeks CSTP. However, trivial to small differences was reported between left and right leg in pre (d = 0.12, 95% CL − 0.49 to 0.73) and post 6-week CSTP (d = 0.04, 95% CL − 0.69 to 0.78). Biering–Sørensen test (BST) shows largely greater performance after 6-week CSTP (98.3 ± 30.1 vs 131.8 ± 19.0 s, d = 1.33, 95% CL 0.54–2.09). A novel measurement, Swiss ball four-point kneeling test was shown to be correlated with the change in BST (r = 0.633).
14
Qi, Zhanhui, Shaowu Li, Mingbing Li, Chaoqun Dang, Dongbo Sun, Dongliang Zhang, Ning Liu, and Suoping Zhang. "Research on the Algorithm Model for Measuring Ocean Waves Based on Satellite GPS Signals in China." Sensors 19, no. 3 (January 28, 2019): 541. http://dx.doi.org/10.3390/s19030541.
Full textAbstract:
In recent years, the GPS wave buoy has been developed for in situ wave monitoring based on satellite GPS signals. Many research works have been completed on the GPS-based wave measurement technology and great progress has been achieved. The basic principle of the GPS wave buoy is to calculate the movement velocity of the buoy using the Doppler frequency shift of satellite GPS signals, and then to calculate the wave parameters from the movement velocity according to ocean wave theory. The shortage of the GPS wave buoy is the occasional occurrence of some unusual values in the movement velocity. This is mainly due to the fact that the GPS antenna is occasionally covered by sea water and cannot normally receive high-quality satellite GPS signals. The traditional solution is to remove these unusual movement velocity values from the records, which requires furthering extend the acquisition time of satellite GPS signals to ensure there is a large enough quantity of effective movement velocity values. Based on the traditional GPS wave measurement technology, this paper presents the algorithmic flow and proposes two improvement measures. On the one hand, the neural network algorithm is used to correct the unusual movement velocity data so that extending the acquisition time of satellite GPS signals is not necessary and battery power is saved. On the other hand, the Gaussian low-pass filter is used to correct the raw directional wave spectrum, which can further eliminate the influence of noise spectrum energy and improve the measurement accuracy. The on-site sea test of the SBF7-1A GPS wave buoy, developed by the National Ocean Technology Center in China, and the gravity-acceleration-type DWR-MKIII Waverider buoy are highlighted in this article. The wave data acquired by the two buoys are analyzed and processed. It can be seen from the processed results that the ocean wave parameters from the two kinds of wave buoys, such as wave height, wave period, wave direction, wave frequency spectrum, and directional wave spectrum, are in good consistency, indicating that the SBF7-1A GPS wave buoy is comparable to the traditional gravity-acceleration-type wave buoy in terms of its accuracy. Therefore, the feasibility and validity of the two improvement measures proposed in this paper are confirmed.
15
Hildebrand, Jens, Gerd Baumgarten, Jens Fiedler, and Franz-Josef Lübken. "Winds and temperatures of the Arctic middle atmosphere during January measured by Doppler lidar." Atmospheric Chemistry and Physics 17, no. 21 (November 10, 2017): 13345–59. http://dx.doi.org/10.5194/acp-17-13345-2017.
Full textAbstract:
Abstract. We present an extensive data set of simultaneous temperature and wind measurements in the Arctic middle atmosphere. It consists of more than 300 h of Doppler Rayleigh lidar observations obtained during three January seasons (2012, 2014, and 2015) and covers the altitude range from 30 km up to about 85 km. The data set reveals large year-to-year variations in monthly mean temperatures and winds, which in 2012 are affected by a sudden stratospheric warming. The temporal evolution of winds and temperatures after that warming are studied over a period of 2 weeks, showing an elevated stratopause and the reformation of the polar vortex. The monthly mean temperatures and winds are compared to data extracted from the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Horizontal Wind Model (HWM07). Lidar and ECMWF data show good agreement of mean zonal and meridional winds below ≈ 55 km altitude, but we also find mean temperature, zonal wind, and meridional wind differences of up to 20 K, 20 m s−1, and 5 m s−1, respectively. Differences between lidar observations and HWM07 data are up to 30 m s−1. From the fluctuations of temperatures and winds within single nights we extract the potential and kinetic gravity wave energy density (GWED) per unit mass. It shows that the kinetic GWED is typically 5 to 10 times larger than the potential GWED, the total GWED increases with altitude with a scale height of ≈ 16 km. Since temporal fluctuations of winds and temperatures are underestimated in ECMWF, the total GWED is underestimated as well by a factor of 3–10 above 50 km altitude. Similarly, we estimate the energy density per unit mass for large-scale waves (LWED) from the fluctuations of nightly mean temperatures and winds. The total LWED is roughly constant with altitude. The ratio of kinetic to potential LWED varies with altitude over 2 orders of magnitude. LWEDs from ECMWF data show results similar to the lidar data. From the comparison of GWED and LWED, it follows that large-scale waves carry about 2 to 5 times more energy than gravity waves.
16
Dangol, Susheel, Prakash Joshi, Suraj KC, Mahesh Thapa, Mahesh Thapa, Bigyan Banjara, Shanker KC, and Stallin Bhandari. "Measurement of Height of Mt. Sagarmatha." Journal on Geoinformatics, Nepal 20, no. 1 (December 1, 2020): 59–66. http://dx.doi.org/10.3126/njg.v20i1.39479.
Full textAbstract:
The height measurement of the highest peak of the world “Sagarmatha” was conducted by Nepal for the first time. The methodology for the measurement was finalized from the workshop held in Kathmandu with the constructive comments from national and international experts. Trignometrical levelling, precise levelling, GNSS survey and gravity survey was conducted. Previous air borne gravity data and present surface gravity data was used to determine the precise regional geoid for this program. Thus orthometric height was determined as 8848.86 m from the ellipsoid height observed at the top of Sagarmatha and precise geoid determined. The height was determined on the base of International Height Reference System (IHRS) and final height was announced jointly from Nepal and China on 8th of December 2020 from Kathmandu and Beijing through virtual media.
17
Wank, Veit, and Corinna Coenning. "On the estimation of centre of gravity height in vertical jumping." German Journal of Exercise and Sport Research 49, no. 4 (April 8, 2019): 454–62. http://dx.doi.org/10.1007/s12662-019-00581-6.
Full text
18
Li, Bin, Qiang Hu, and Zhijun Fu. "Adaptive online estimation of centre of gravity height for commercial vehicles." International Journal of Heavy Vehicle Systems 28, no. 2 (2021): 206. http://dx.doi.org/10.1504/ijhvs.2021.10038431.
Full text
19
Fu, Zhijun, Qiang Hu, and Bin Li. "Adaptive online estimation of centre of gravity height for commercial vehicles." International Journal of Heavy Vehicle Systems 28, no. 2 (2021): 206. http://dx.doi.org/10.1504/ijhvs.2021.115579.
Full text
20
Li, Xiong, and Hans‐Jürgen Götze. "Ellipsoid, geoid, gravity, geodesy, and geophysics." GEOPHYSICS 66, no. 6 (November 2001): 1660–68. http://dx.doi.org/10.1190/1.1487109.
Full textAbstract:
Geophysics uses gravity to learn about the density variations of the Earth’s interior, whereas classical geodesy uses gravity to define the geoid. This difference in purpose has led to some confusion among geophysicists, and this tutorial attempts to clarify two points of the confusion. First, it is well known now that gravity anomalies after the “free‐air” correction are still located at their original positions. However, the “free‐air” reduction was thought historically to relocate gravity from its observation position to the geoid (mean sea level). Such an understanding is a geodetic fiction, invalid and unacceptable in geophysics. Second, in gravity corrections and gravity anomalies, the elevation has been used routinely. The main reason is that, before the emergence and widespread use of the Global Positioning System (GPS), height above the geoid was the only height measurement we could make accurately (i.e., by leveling). The GPS delivers a measurement of height above the ellipsoid. In principle, in the geophysical use of gravity, the ellipsoid height rather than the elevation should be used throughout because a combination of the latitude correction estimated by the International Gravity Formula and the height correction is designed to remove the gravity effects due to an ellipsoid of revolution. In practice, for minerals and petroleum exploration, use of the elevation rather than the ellipsoid height hardly introduces significant errors across the region of investigation because the geoid is very smooth. Furthermore, the gravity effects due to an ellipsoid actually can be calculated by a closed‐form expression. However, its approximation, by the International Gravity Formula and the height correction including the second‐order terms, is typically accurate enough worldwide.
21
Germann, S. T., and R. Isermann. "Determination of the Centre of Gravity Height of a Vehicle with Parameter Estimation." IFAC Proceedings Volumes 27, no. 8 (July 1994): 563–68. http://dx.doi.org/10.1016/s1474-6670(17)47768-8.
Full text
22
Smolnicki, Tadeusz, and Mariusz Stańco. "Determination of Centre of Gravity of Machines with the Rail Undercarriage." Solid State Phenomena 165 (June 2010): 359–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.359.
Full textAbstract:
Determination of centre of gravity of rotational handling machines with the rail undercarriage can be conducted by the measurement of rails strains induced by the wheels of driving machine. At the properly selected combination of superstructure locations with respect to undercarriage, it is possible to eliminate the systematic measurement failures. Determination of centre of gravity is necessary for proper weighing of the machine and selection counterweight. Otherwise it can cause the loss of stability or fast degradation of superstructure rotation bearing.
23
Forslund, R. R. "The power function as a simple stem profile examination tool." Canadian Journal of Forest Research 21, no. 2 (February 1, 1991): 193–98. http://dx.doi.org/10.1139/x91-023.
Full textAbstract:
Formulae are presented for calculating the volume, surface area, centre of gravity, centre of mass, form, taper, and instantaneous slope of the power function. A profile plotting technique is also used that allows visual comparisons between average stem profiles independent of the size and taper of individual stems. The technique is used to demonstrate that the position near 30% of the height from the base of the stem is a position of form stability for volume estimation. Using the paracone profile model (a power function midway between a paraboloid and a cone) with the diameter at the 30% position and the total stem height, individual stem volume estimates within 10% of the true volume (95% confidence) are obtained once again using a sample of 50 yearling aspen (Populustremuloides Michx.). The plotting technique is then applied to the aspen sample, and the average profiles support the hypothesis that juvenile stems may begin life as paraboloids. The average centre of gravity, the average centre of mass, the sectional form, the average form, and the taper of the stems are also examined and are shown to be quantitative indicators of the plotted profile characteristics.
24
Strickland, Stephen L., Michael Shearer, and Karen E. Daniels. "Spatiotemporal measurement of surfactant distribution on gravity–capillary waves." Journal of Fluid Mechanics 777 (July 20, 2015): 523–43. http://dx.doi.org/10.1017/jfm.2015.352.
Full textAbstract:
Materials adsorbed onto the surface of a fluid – for instance, crude oil, biogenic slicks or industrial/medical surfactants – will move in response to surface waves. Owing to the difficulty of non-invasive measurement of the spatial distribution of a molecular monolayer, little is known about the dynamics that couple the surface waves and the evolving density field. Here, we report measurements of the spatiotemporal dynamics of the density field of an insoluble surfactant driven by gravity–capillary waves in a shallow cylindrical container. Standing Faraday waves and travelling waves generated by the meniscus are superimposed to create a non-trivial surfactant density field. We measure both the height field of the surface using moiré imaging, and the density field of the surfactant via the fluorescence of NBD-tagged phosphatidylcholine, a lipid. Through phase averaging stroboscopically acquired images of the density field, we determine that the surfactant accumulates on the leading edge of the travelling meniscus waves and in the troughs of the standing Faraday waves. We fit the spatiotemporal variations in the two fields using an ansatz consisting of a superposition of Bessel functions, and report measurements of the wavenumbers and energy damping factors associated with the meniscus and Faraday waves, as well as the spatial and temporal phase shifts between them. While these measurements are largely consistent for both types of waves and both fields, it is notable that the damping factors for height and surfactant in the meniscus waves do not agree. This raises the possibility that there is a contribution from longitudinal waves in addition to the gravity–capillary waves.
25
Zhao, Xin Tong, H. Z. Jiang, S. T. Zheng, and Jun Wei Han. "Precision Gravity Center Position Measurement System for Heavy Vehicles." Key Engineering Materials 315-316 (July 2006): 788–91. http://dx.doi.org/10.4028/www.scientific.net/kem.315-316.788.
Full textAbstract:
Knowledge of a vehicle’s inertial parameters is essential for safety research and accident reconstruction. A precision measure system is proposed to determine the weight and gravity center for heavy vehicles. Based on a static gravity measuring principle with three measuring points, a hydraulically driven 2-DOF motion platform is developed. The transfer function model is derived for the hydraulically driven system. By means of a degree-of-freedom control scheme, the platform can realize accurate positioning to construct two intersected planes and work out the three-dimensional coordinates of the vehicle gravity center. Experiments demonstrate that the system has less than 0.3% measurement error in weight, and is able to measure the gravity centre accurately with deviation ≤3mm in X and Y direction, and ≤5mm in Z direction.
26
Shabani, Babak, Jason Lavroff, Damien S. Holloway, Michael R. Davis, and Giles A. Thomas. "The influence of the centre bow and wet-deck geometry on motions of wave-piercing catamarans." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 233, no. 2 (February 1, 2018): 474–87. http://dx.doi.org/10.1177/1475090217753761.
Full textAbstract:
The effects of tunnel height and centre bow length on the motions of a 112-m wave-piercer catamaran with an above-water centre bow were investigated through model tests. Five alternative centre bow configurations were considered, and multiple series of model tests were conducted in regular head sea waves. The results showed that both heave and pitch increased over a wide range of wave encounter frequency as the wet-deck height of the catamaran model increased. However, increasing the length of the centre bow showed an increase in the pitch but a decrease in the heave for a limited range of wave encounter frequency near the heave and pitch resonance frequencies of the catamaran model. The positions of minimum vertical displacement were found to be aft of the longitudinal centre of gravity, between 20% and 38% of the overall length from the transom. Increase in the wet-deck height and consequently the archway clearance between the main hulls and centre bow also resulted in an increase in the vertical displacement relative to the undisturbed water surface in the centre bow area. The results also indicated the vulnerability to wet-deck slamming for the different bow and wet-deck designs.
27
Hu, Jingwen. "Height of head centre of gravity predicts paediatric head injury severity in short-distance falls." Evidence Based Medicine 22, no. 1 (November 10, 2016): 36. http://dx.doi.org/10.1136/ebmed-2016-110558.
Full text
28
Cheng, Yi, Jin Luo, and Chun Bo Xiu. "The Research on Tikhonov Regularization Algorithm in Airborne Gravity Data Downward Continuation." Key Engineering Materials 439-440 (June 2010): 674–78. http://dx.doi.org/10.4028/www.scientific.net/kem.439-440.674.
Full textAbstract:
Based on the remove-restore technique, the application of the Tikhonov regularization algorithm to reduce the effect of measurement error in the airborne gravity dada in researched. By the experiments of two kinds airborne gravity data, which having constant system error and casual system error, the compare of different downward continuation algorithm is performed. According to the results of simulations, the Tikhonov regularization algorithm can effectively reduce the effect of height and the measurement error in the airborne gravity data downward continuation compared to other algorithm.
29
Du, Wen Qin, Xiao Liang liu, and Hong Jin Qi. "Measurement and Estimation of Yarn Pore Size Distribution by Gravity Class." Advanced Materials Research 146-147 (October 2010): 1458–62. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1458.
Full textAbstract:
To investigate the contribution of yarn pore size distribution to fabric pores structure, in this paper, based on the balance relationship between the capillary height and the hydrostatic pressure of the liquid in the yarn, we designed and assembled a device for measurement of μm scale pore size distribution of the cotton yarn. Through comparison and analysis of data and considering the very low water content in the yarn, we increased the number of yarn, designed a special cutting device and improved the measurement accuracy of weight. Finaly, we obtained histograms and curves with highly accurate (0.0001g) and good reproducibility. The results show that the yarn pore size is in tens-hundreds μm and displays a concave-like distribution, while the fabric pore size change is much more complex, suggesting that the pore in the fabric is not a simple summation of the pore in the yarn.
30
Hughes, Jonathon, Sabine Maguire, Michael Jones, Peter Theobald, and Alison Kemp. "Biomechanical characteristics of head injuries from falls in children younger than 48 months." Archives of Disease in Childhood 101, no. 4 (September 17, 2015): 310–15. http://dx.doi.org/10.1136/archdischild-2014-306803.
Full textAbstract:
BackgroundA fall-height threshold is important when evaluating the likelihood of structural head injury or abusive head trauma. This study investigates witnessed falls to correlate the fall characteristics with the extent of injury.MethodCase–control study of children aged ≤48 months who attended one hospital following a fall from <3 m (10 ft), comparing cases who sustained a skull fracture or intracranial injury (ICI) with controls, who had minor head injuries. Characteristics included: the mechanism of injury, surface of impact, site of impact to the head and fall height.ResultsForty-seven children had a skull fracture or ICI, while 416 children had minor head injuries. The mean fall height for minor head injuries was significantly lower than that causing skull fracture/ICI (p<0.001). No skull fracture/ICI was recorded in children who fell <0.6 m (2 ft), based on the height of the head centre of gravity. Skull fractures/ICI were more likely in children aged ≤12 months (p<0.001) from impacts to the temporal/parietal or occipital region (p<0.001), impacts onto wood (p=0.004) and falls from a carer's arms, particularly when on stairs (p<0.001). No significant difference was reported between the mean fall heights of children who had a simple skull fracture (n=17) versus those who had a complex fracture or ICI (n=30).ConclusionsAn infant is more likely to sustain a skull fracture/ICI from a fall above a 0.6 m (2 ft) threshold, based on the height of the head centre of gravity, or with a parietal/temporal or occipital impact. These variables should be recorded when evaluating the likelihood of skull fracture/ICI.
31
Gabl, Roman, Thomas Davey, Edd Nixon, and David M. Ingram. "Accuracy Analysis of the Measurement of Centre of Gravity and Moment of Inertia with a Swing." Applied Sciences 11, no. 12 (June 9, 2021): 5345. http://dx.doi.org/10.3390/app11125345.
Full textAbstract:
Floating devices under wave and current loads are typically designed based on numerical methods followed by a validation with experimental investigations. This allows an independent check due to the comparison of two different modelling approaches based on different assumptions. At an early stage of the project, numerical simulations are based on theoretical (ideal) values of the centre of gravity (CG) and moment of inertia (MI). The building process of a scaled model results very often in a requested simplification of certain parts, which can influence the CG and also the MI of the scaled model. Knowing those discrepancies allows us to improve the comparability of both approaches but the measurement of those values is connected with either a higher uncertainty or a high level of effort. A significant improvement of such measurements can be reached by the deployment of a specific experimental set-up. This paper presents the classification of the newly designed swing with a high accuracy inertial inclinometer, which was verified by the marker-based motion capturing system. The achieved experiences are useful for the future use of the set-up as well as similar investigations. The comparison with the theoretical values for the swing as well as an example model showed very good agreements and a high accuracy of few millimetres for the CG and an error smaller 1% for MI.
32
Ojie, Oseikhuemen Osemekhian Davis, Reza Saatchi, and Mahdieh Saatchi. "Demonstration of the Effect of Centre of Mass Height on Postural Sway Using Accelerometry for Balance Analysis." Technologies 8, no. 2 (April 22, 2020): 20. http://dx.doi.org/10.3390/technologies8020020.
Full textAbstract:
The effect of center of mass (COM) height on stand-still postural sway analysis was studied. For this purpose, a measurement apparatus was set up that included an accelerometry device attached to a rod: three plumb lines, positioned at 50, 75 and 100 cm to an end of the rod, each supported a plumb bob. Using a vice mechanism, the rod was inclined from vertical (0 degree inclination) in steps of 5 degrees to 90 degrees. For each inclination, the corresponding inclination angle was manually measured by a protractor and the positions of the three plumb bobs on the ground surface were also manually measured using a tape measure. Algebraic operations were used to calculate the inclination angle and the associated displacements of the plumb bobs on the ground surface from the accelerometry data. For each inclination angle, the manual and accelerometry calculated ground displacement were close. The height of COM, where the measurement was taken, affected the projected displacement on the ground surface. The COM height had a nonlinear double-effect relationship with sway as it can affect both the angle and projected sway. Normalization of the COM height was used to reduce this effect for comparison purposes.
33
Chen, Y. C., H. H. Huang, and J. B. Lin. "Application of vector finite screw analysis to determine the roll centre from wheel points." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 11 (September 14, 2011): 2586–96. http://dx.doi.org/10.1177/0954406211406614.
Full textAbstract:
In kinematic and compliance testing for suspensions, great importance is attached to the measurement of the instant centre and roll centre. As the suspension construction is truly three-dimensional, the screw axis theory can afford a much more accurate kinematic analysis. The purpose of this study was to present a vector finite displacement method (FSAv) for the kinematic analysis of instant centre and roll centre of suspensions. Two suspension simulation models, with and without approximately singular screw parameter, respectively, were employed to investigate the efficiency of the proposed method. It was found that the FSAv method prevailed over the method of general finite screw axis. In addition, it was not necessary to calculate the velocity matrix from the derivatives. This proposed method, therefore, is suitable for determining the roll centre height and the related parameters of instant centre. Moreover, it can be expanded for the measurement of the kingpin axis as well.
34
Street, Glenn, Scott McMillan, Wayne Board, Mike Rasmussen, and J. Michael Heneghan. "Sources of Error in Determining Countermovement Jump Height with the Impulse Method." Journal of Applied Biomechanics 17, no. 1 (February 2001): 43–54. http://dx.doi.org/10.1123/jab.17.1.43.
Full textAbstract:
A comprehensive error analysis was performed on the impulse method. To evaluate the potential errors, jump height was recalculated after alteringoneof the measurement or calculation techniquaes while leaving the others unchanged, and then comparing it to the reference jump height (best estimate of true jump height). Measurement techniques introduced the greatest error. Low-pass filters with cutoff frequencies < 580 Hz led to systematic underestimations of jump height, ≤26%. Low sampling frequencies (<1,080 Hz) caused jump height to be underestimated by ≤4.4%. Computational methods introduced less error. Selecting takeoff too early by using an elevated threshold caused jump height to be overestimated by ≤1.5%. Other potential sources of computational error: (a) duration of body weight averaging period; (b) method of integration; (c) gravity constant; (d) start of integration; (e) duration of offset averaging period; and (f) sample duration, introduced < 1% error to the calculated jump height. Employing the recommended guidelines presented in this study reduces total error to ≤ ±0.76%. Failing to follow the guidelines can lead to average errors as large as 26%.
35
Janák, J., S. Slovík, Z. Fašková, and K. Mikula. "Disturbing potential and its geometrical properties." Slovak Journal of Civil Engineering 18, no. 3 (September 1, 2010): 27–32. http://dx.doi.org/10.2478/v10189-010-0014-4.
Full textAbstract:
Disturbing potential and its geometrical propertiesDisturbing potential is probably the most crucial quantity in gravity field modelling. Usually, the disturbing potential is converted into a geoid height or height anomaly and presented as a contour map of a geoid or quasigeoid. In our contribution we present a spatial geometry of the equipotential surfaces of the disturbing potential around the Earth. The models presented are solutions of a mixed boundary value problem; they combine the Neumann and Dirichlet boundary conditions, and are solved using the Finite Element Method. The boundary values are generated from an EGM2008 geopotential model. However, the combination of the terrestrial measurement and the satellite gravity gradiometry-originated data can be used in the future. Therefore this work can be seen as a preliminary study before the exploitation of the actual gravity gradiometry data. The disturbing potential model is presented in the form of a 3D model up to an altitude of 20000 km above the Earth's surface.
36
Watanabe, Hiroyuki, Meguru Fujii, Masumi Yoshimoto, Hiroshi Abe, Naruaki Toda, Reiji Higashiyama, and Naonobu Takahira. "Pathogenic Factors Associated With Osgood-Schlatter Disease in Adolescent Male Soccer Players: A Prospective Cohort Study." Orthopaedic Journal of Sports Medicine 6, no. 8 (August 1, 2018): 232596711879219. http://dx.doi.org/10.1177/2325967118792192.
Full textAbstract:
Background: A previous cross-sectional study reported that pathogenic factors associated with Osgood-Schlatter disease (OSD) in adolescent athletes include increased quadriceps muscle tightness, lower leg malalignment, and development of apophysitis in the tibial tuberosity. Purpose: To confirm these pathogenic factors associated with OSD in a longitudinal study with regard to physical function and performance. Study Design: Cohort study; Level of evidence, 2. Methods: In this study, 37 boys (mean age, 10.2 ± 0.4 years) were recruited from 2 soccer teams at an elementary school. This cohort study was conducted over an observation period of 1 year, with measurements recorded at baseline, followed by screening for OSD every 6 months. Variables evaluated at baseline included physical function (morphometry, joint flexibility, and lower extremity alignment), presence of Sever disease, and kicking motion. Results: Pathogenic factors associated with OSD in the support leg of adolescent male soccer players included height, weight, body mass index, quadriceps femoris muscle tightness in the kicking and support legs, and gastrocnemius muscle tightness, soleus muscle tightness, and medial longitudinal arch in the support leg. Additional factors included a diagnosis of Sever disease and distance from the lateral malleolus of the support leg’s fibula to the center of gravity during kicking. Conclusion: The onset of OSD was found to be affected by many factors, including developmental stage, physical attributes, and pre-existing apophysitis. In particular, a diagnosis of Sever disease and backward shifting of the center of gravity during kicking increased the risk of the subsequent onset of OSD, suggesting that these factors are very important as a possible focus for interventions.
37
Yoshida, Koei, Ryo Takahashi, Hiroyuki Torikai, and Akihiko Ito. "Effect of Gravity on Radiative Heat Feedback on Small-Scale Pool Fires Using the Radiative Absorption Model." Modern Applied Science 10, no. 10 (July 7, 2016): 150. http://dx.doi.org/10.5539/mas.v10n10p150.
Full textAbstract:
The flame characteristics of pool fires such as their height vary depending on gravity. To improve our understanding of the effects of gravity on flame characteristics, we experimentally investigated small-scale pool fires under conditions of normal to partial gravity; using the drop tower at Hirosaki University in Japan to obtain arbitrary partial gravity condition, which varied from 1 G to 0.55 G. We performed the measurement of the temperature distribution with a thermocouple and that of the flame shape with a digital camera. Based on these data, we estimated radiative heat feedback using our new model “The radiative absorption model”. It becomes easy to estimate radiative heat transfer using this model if flames have complicated shapes and time variability. From these analyses, we made clear that the radiative heat feedback of small-scale pool fires decreases under partial gravity environment.
38
Klongratog, Bhanupol, Warit Pengto, Todsaporn Wornkert, and Anupong Srongprapa. "Estimation of Vertical Jump Height Using Nintendo Wii Remote IR Camera." E3S Web of Conferences 72 (2018): 02004. http://dx.doi.org/10.1051/e3sconf/20187202004.
Full textAbstract:
In this article, we proposed to measure the heights of countermovement jumps which are recorded in term of vertical leap by using the Wii Remote infrared camera. According to the physical principles, positions of the movement were detected based on the rules regarding conservation of energy, motion under gravity, and coordinate system. The obtained results were compared with that of the slow-motion measurements. The experiment involved 30 basketball players whose jump results were slightly deviated from the vertical measurement of the coordinate system. Therefore, the results should be calibrated each time the new system is installed.
39
Pyrchla, Krzysztof, Arkadiusz Tomczak, Grzegorz Zaniewicz, Jerzy Pyrchla, and Paulina Kowalska. "Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study." Sensors 20, no. 21 (October 23, 2020): 6044. http://dx.doi.org/10.3390/s20216044.
Full textAbstract:
This article presents possible applications of a dynamic gravity meter (MGS-6, Micro-g LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.
40
Cooke, Brian. "Selection of operative centrifuge radius to minimize stress error in calculations." Canadian Geotechnical Journal 28, no. 1 (February 1, 1991): 160–61. http://dx.doi.org/10.1139/t91-017.
Full textAbstract:
In a centrifuge model, the vertical stress distribution is nonlinear because of the variation of the model's "gravity" field with the centrifuge radius from the top to the bottom of the model. Thus in calculating the centrifugal acceleration, and hence the scale of the model, care must be taken to use the definition of centrifuge radius that minimizes the stress error in the model profile. This paper demonstrates that this optimum radius is measured from the centre of rotation to a point 0.59 times the model height from the bottom of the model. Key words: centrifuge, stress, error.
41
Pires, E. M., R. M. Nogueira, D. S. Pina, C. L. M. Manica, L. R. A. Faroni, and P. S. A. Moreira. "Walking stability of Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae)." Brazilian Journal of Biology 76, no. 3 (April 19, 2016): 568–76. http://dx.doi.org/10.1590/1519-6984.16914.
Full textAbstract:
Abstract Results obtained in studies can contribute to the advancement of science and innovative methods and techniques for developing practical activities. Reporting conditions that may restrict the implementation of research is critical to ensure the optimal development of further technical studies. The objective of this study was to assess the walking stability of R. dominica on a flat and smooth surface. The study was based on the determination of mortality, morphology and walking stability of the insect outside the grain mass, on a flat and smooth surface. Mortality of adults of this Coleoptera in conditions with and without food was similar, which explains the difficulty that this insect had for accessing the food source on the flat and smooth surface. The measurements of body length (BOL), width (BOW) and height (BOH) of R. dominica were compared with those of Tribolium castaneum (Coleoptera: Tenebrionidae), which showed good ability to walk in these conditions. This study indicated that the former presents lower BOL and BOW, and greater BOH than the second, and all these variables showed differences when analyzed simultaneously by means of the construction of multivariate morphometric indices (Width × Height, Length × Height and Height × Length × Width). These morphometric variables, together with the definition of the geometry most similar to the body shape, resulted in determination of the center of gravity (CG) and static rollover threshold (SRTgeom) for both species. Rhyzopertha dominica and T. castaneum presented CGs considered high and low, respectively, and together with the values obtained for SRTgeom, may justify that R. dominica can be considered a less stable species during movement, and presents greater risk of rollover on flat and smooth surfaces.
42
Kumari, Pooja, V. Raghunandan, and P. Biswal. "Diurnal variation in aviation significant gravity-dependent and gravity-independent anthropometric parameters." Indian Journal of Aerospace Medicine 65 (August 6, 2021): 5–9. http://dx.doi.org/10.25259/ijasm_61_2020.
Full textAbstract:
Introduction: Anthropometric parameters need to be accurately measured because of their direct implications in selection of aircrew, aircrew-cockpit compatibility, and cockpit workspace design. Some of these parameters have significant diurnal variation, hence, measurement of these parameters in particular time of day becomes important. Quantification of these diurnal variations among some of the aviation significant parameters was the desired objective of the study. Material and Methods: In a prospective repeated measure design, anthropometric parameters of a total of 35 volunteers were measured in the standard defined protocol from 0800h to 1600h, at an interval of every 2h, using Institute of Aerospace Medicine (IAM) Anthropometry Platform. The data were analyzed to observe and quantify changes in diurnal variations in both gravity-dependent and gravity-independent parameters. A maximum value of 0.4 cm was taken as intraobserver variations based on the results of a pilot study. Results: There was a statistically significant decrement in the values of gravity-dependent anthropometric parameters from morning to evening; the difference being more after 1200h. Most of the gravity-independent parameters did not show any significant changes from 0800h to 1600h, except leg length, which showed a decrement overtime, the difference being statistically significant after 1200h. Conclusion: The study revealed a statistically significant variation of gravity-dependent anthropometric parameters from the baseline which could be because of the effect of erect posture on the intervertebral disc height and axial compressive loads on the spine. This became practically significant after 1200h. However, most of the gravity-independent parameters did not show any significant variations. Based on the results of this study, anthropometric measurements should be done in the morning hours preferably before 1200h.
43
Pérez-Belloso, Ana Juana, Manuel Coheña-Jiménez, Maria Eugenia Cabrera-Domínguez, Antonio Francisco Galan-González, Antonia Domínguez-Reyes, and Manuel Pabón-Carrasco. "Influence of Dental Malocclusion on Body Posture and Foot Posture in Children: A Cross-Sectional Study." Healthcare 8, no. 4 (November 14, 2020): 485. http://dx.doi.org/10.3390/healthcare8040485.
Full textAbstract:
The number of studies that investigate the correlations between the temporomandibular system and body posture, postural control, or the distribution of plantar pressure has recently been increasing. However, most of the existing information is not conclusive. Therefore, the study objective was to evaluate if the features of dental malocclusion are correlated with body posture alterations at the lower limb level. This is a multicentre cross-sectional study with 289 children (8–14 years). Angle’s molar relation was analysed at the dental level. The postural control and the plantar pressure distribution were recorded via a force platform. Correlation and inferential analysis between the Angle class and the foot’s biomechanics were tested. The centre of gravity is anteriorised in Angle’s Class II in both the molar class (p ≤ 0.001) and the canine class (p ≤ 0.001). Likewise, a relationship was observed between the contact surface and Angle’s classes, being higher in class III than in II (p ≤ 0.001). The plantigrade phase is shortened in Angle’s Class III. A relationship was found between Angle’s Class II and a forward movement of the centre of gravity. No relationship was found between the Foot Posture Index and the truncated scaphoid height and the dental classification. An evident relationship between the gait typology and dental malocclusion was not found.
44
Rosdianto, Haris. "PENENTUAN PERCEPATAN GRAVITASI PADA PERCOBAAN GERAK JATUH BEBAS DENGAN MEMANFAATKAN RANGKAIAN RELAI." SPEKTRA: Jurnal Fisika dan Aplikasinya 2, no. 2 (October 17, 2017): 107. http://dx.doi.org/10.21009/spektra.022.03.
Full textAbstract:
The determination of the gravity acceleration through free fall experiment using the relay circuit has been done. This study aims to make free-fall experiment design using relay circuit, and determine the value of gravity acceleration by using this experiment design. The measurement method used in this study is to measure the free fall time of the object using a stopwatch that can work automatically. The result of this research is this experiment design can be used to get the free fall time data automatically. The values of gravity acceleration to 10 cm, 20 cm, 30 cm, 40 cm and 50 cm respectively, are 9.80952381 m/s2, 9.814058957 m/s2, 9.845 m/s2, 9.858283385 m/s2, and 9.829645226 m/s2. So that the average acceleration value of the five variations of height is 9.831302275 m/s2.
Keywords: Free fall motion, gravity acceleration, relay circuit.
45
Hunt, Andrew, Richard Foster-Turner, and Ross Drury. "Propellant Slosh Force and Mass Measurement." International Journal of Aerospace Engineering 2018 (May 31, 2018): 1–9. http://dx.doi.org/10.1155/2018/3026872.
Full textAbstract:
We have used electrical capacitance tomography (ECT) to instrument a demonstration tank containing kerosene and have successfully demonstrated that ECT can, in real time, (i) measure propellant mass to better than 1% of total in a range of gravity fields, (ii) image propellant distribution, and (iii) accurately track propellant centre of mass (CoM). We have shown that the ability to track CoM enables the determination of slosh forces, and we argue that this will result in disruptive changes in a propellant tank design and use in a spacecraft. Ground testing together with real-time slosh force data will allow an improved tank design to minimize and mitigate slosh forces, while at the same time keeping the tank mass to a minimum. Fully instrumented Smart Tanks will be able to provide force vector inputs to a spacecraft inertial navigation system; this in turn will (i) eliminate or reduce navigational errors, (ii) reduce wait time for uncertain slosh settling, since actual slosh forces will be known, and (iii) simplify slosh control hardware, hence reducing overall mass. ECT may be well suited to space borne liquid measurement applications. Measurements are independent of and unaffected by orientation or levels of g. The electronics and sensor arrays can be low in mass, and critically, the technique does not dissipate heat into the propellant, which makes it intrinsically safe and suitable for cryogenic liquids. Because of the limitations of operating in earth-bound gravity, it has not been possible to check the exact numerical accuracy of the slosh force acting on the vessel. We are therefore in the process of undertaking a further project to (i) build a prototype integrated “Smart Tank for Space”, (ii) undertake slosh tests in zero or microgravity, (iii) develop the system for commercial ground testing, and (iv) qualify ECT for use in space.
46
Bezjazychnyj, V. F., K. A. Vinogradov, and O. V. Vinogradova. "DETERMINATION OF GEOMETRICAL PARAMETERS OF GAS TURBINE BLADES BASED ON COORDINATE MEASUREMENT BY STRUCTURAL AND PARAMETRIC ANALYSIS METHODS." Spravochnik. Inzhenernyi zhurnal, no. 277 (April 2020): 31–37. http://dx.doi.org/10.14489/hb.2020.04.pp.031-037.
Full textAbstract:
A method for determining the parameters of the turbine blades geometry (angles of the inlet and outlet edges, thickness, etc.), as well as the coordinates of the centers of gravity of the blades (height) according to the coordinate measurements of the profiles is proposed. These parameters are used to evaluate the gas-dynamic efficiency of the blade row and the strength characteristics of the turbine blades on the basis of one-dimensional and two-dimensional models widely used in engineering practice.
47
Bezjazychnyj, V. F., K. A. Vinogradov, and O. V. Vinogradova. "DETERMINATION OF GEOMETRICAL PARAMETERS OF GAS TURBINE BLADES BASED ON COORDINATE MEASUREMENT BY STRUCTURAL AND PARAMETRIC ANALYSIS METHODS." Spravochnik. Inzhenernyi zhurnal, no. 277 (April 2020): 31–37. http://dx.doi.org/10.14489/hb.2020.04.pp.031-037.
Full textAbstract:
A method for determining the parameters of the turbine blades geometry (angles of the inlet and outlet edges, thickness, etc.), as well as the coordinates of the centers of gravity of the blades (height) according to the coordinate measurements of the profiles is proposed. These parameters are used to evaluate the gas-dynamic efficiency of the blade row and the strength characteristics of the turbine blades on the basis of one-dimensional and two-dimensional models widely used in engineering practice.
48
Raja Mohd Yazit, Raja Nur Syaheeza, Elina Mohd Husini, Mohd Khedzir Khamis, and Yakubu Aminu Dodo. "Assessment on Accuracy of Design Science Research (DSR) Framework as a Daylighting Measurement Tool for Islamic Religious School." Environment-Behaviour Proceedings Journal 6, no. 17 (August 15, 2021): 81–91. http://dx.doi.org/10.21834/ebpj.v6i17.2877.
Full textAbstract:
Daylight efficiency correlates to window design. Guidelines recommend a 20 per cent window-to-floor ratio (WFR) at 900mm windowsill height, where acceptable 300 lx to 500 lx measured at 900mm working plane height. However, Islamic religious schools use a 300mm height table known as ‘rehal’. Studies neglect the difference in required working plane height that effect window design and the illuminance level. A study was established to propose Syaheeza’s Daylight Rule of Thumb (DRT) for Islamic religious schools. This paper aims to highlight the reliability of the methodology framework used in Syaheeza’s DRT, such as surveys, Arabic handwriting performance assessment and computer simulations. Keywords: Daylighting; Islamic religious school; methodology framework eISSN: 2398-4287© 2021. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v6i17.2877
49
Kyselovičová, Oľga, and Erika Zemková. "Postural Stability in Aerobic Gymnastics Specific Positions." Sport Science Review 19, no. 3-4 (August 1, 2010): 109–16. http://dx.doi.org/10.2478/v10237-011-0020-0.
Full textAbstract:
Postural Stability in Aerobic Gymnastics Specific Positions The study compares the effect of maximal jumps and sport-specific exercises on parameters of balance. Two balance elements (free support vertical split and frontal split) were analyzed in a group of 8 aerobic gymnasts (average age = 17,0 ± 1,3 years, average body height = 163,0 ± 6,9 cm, average body weight = 54,5 ± 6,12 kg, BMI 20,4 ± 1,46 kg.m-2). The FiTRO Sway Check stabilographic system, allowing the monitoring of horizontal movement of centre of gravity with the help of dynamometric board, was used for assessment. Stabilographic parameter of the velocity of the centre of pressure (mean and in antero-posterior and medio-lateral directions) was registered at 100 Hz. The results show significant differences in average sway length in medio-lateral and antero-posterior direction, in both analysed difficulty elements. This indicates that balance impairment after exercise and its readjustments to pre-exercise level depends not only on intensity of proprioceptive stimulation but also on type of exercise.
50
QI, HUIRONG, and MEI LIU. "APPLICATION OF A ONE-DIMENSIONAL POSITION SENSITIVE CHAMBER ON SYNCHROTRON RADIATION." International Journal of Modern Physics: Conference Series 27 (January 2014): 1460142. http://dx.doi.org/10.1142/s2010194514601422.
Full textAbstract:
In the last few years, wire chambers have been frequently used for X-ray detection because of their low cost, large area and reliability. X-ray diffraction is an irreplaceable method for powder crystal lattice measurements. A one-dimensional single-wire chamber has been developed in our lab to provide high position resolution for powder diffraction experiments using synchrotron radiation. There are 200 readout strips of 0.5 mm width with a pitch of 1.0 mm in the X direction, and the working gas is a mixture of Ar and CO2 (90/10). The one-dimensional position of the original ionization point is determined by the adjacent strip's distribution information using the center of gravity method. Recently, a study of the detector's performance and diffraction image was completed at the 1W1B laboratory of the Beijing Synchrotron Radiation Facility (BSRF) using a sample of SiO2. Most of the relative errors between the measured values of diffraction angles and existing data were less than 1%. The best position resolution achieved for the detector in the test was 71 μm (σ value) with a 20 μm slit collimator. Finally, by changing the detector height in incremental distances from the center of the sample, the one-dimensional detector achieved a two-dimensional diffraction imaging function, and the results are in good agreement with standard data.