Platform Height Research Articles

Hormonal and Metabolic Responses to a Single Bout of Resistance Exercise in Prader-Willi Syndrome

Background: Prader-Willi syndrome (PWS) is characterized by excessive adiposity. Excess adiposity negatively affects hormonal and metabolic responses to aerobic exercise. This study determined whether PWS and/or adiposity affected hormonal and metabolic responses to resistance exercise. Methods: Eleven children with PWS (11.4 ± 3.1 years, 43.9 ± 7.5% body fat), 12 lean children (9.3 ± 1.4 years, 18.3 ± 4.9% body fat), and 13 obese children (9.6 ± 1.3 years, 40.3 ± 5.2% body fat) participated. The children stepped onto an elevated platform while wearing a weighted vest for 6 sets of 10 repetitions per leg (sets separated by 1 min of rest). For the children with PWS, the platform height was 23.0 cm and vest load was computed as (20% of stature × 50% of lean body mass)/23.0 cm. For the controls, the platform height was 20% of the stature and vest load 50% of the lean body mass. Blood samples were obtained before, immediately after, and during recovery from exercise (+15, +30, and +60 min). Results: All groups had similar catecholamine, insulin, and glucagon responses. The groups showed no major differences in glucose and lactate levels. The PWS children demonstrated earlier increases in fatty acids during recovery and higher glycerol and ketone levels than the controls. Conclusion: The PWS children demonstrated largely intact hormonal, glycolytic, and lipolytic responses to lower-body resistance exercise. In PWS, elevated ketone levels suggest an incomplete fat oxidation.

Labyrinth Seal Design Optimization Based on Quadratic Regression Orthogonal Experiment

The influence of labyrinth seal structure parameters and their interaction on the characteristics of leakage amount are numerically investigated by conducting a quadratic regression orthogonal experiment. To determine the optimal structure parameters of the steam seal for minimizing the leakage amount, a reliable regression equation that does not lack of fit is established. The flow characteristics of the fluid in the labyrinth seal are analyzed in detail. Results show that the leakage amount is greatly influenced by seal cavity depth, convex platform height, seal tooth thickness, and tooth tip clearance, with the tip clearance having the most significant effect. The interaction among the four items exerts a certain impact on the leakage amount. The proposed regression equation exhibits a good significance and does not lack of fit. After optimization, the labyrinth seal demonstrates increased entropy and energy dissipation at the tip of the seal tooth, as well as decreased speed and inertia effect in the cavity, suggesting that the resistance leakage performance of the optimized labyrinth seal is improved.

Control system of a performance test-bed for frost protection wind machines

Abstract: To test the performance and optimize operational parameters of various frost protection wind machines, a control system of performance test-bed was designed and developed based on Programmable Logic Controller (PLC) and touch screen. The system realized automatic control of operational parameters including hydraulic platform height, impeller rotation speed, depression angle, rotation range and cycle. Field case study results shows that the control accuracy of all the parameters was achieved with the average errors of 2.11 cm for height, 9.5 r/min for impeller rotation speed, 0.83° for pan-tilt rotation range and 0.061 min for rotation cycle. With the control of the test-bed, the performances of various wind machines, such as the distribution of airflow and temperature, and frost protection effect, could be tested under various working conditions, which provide experiment supports for developing wind machines adapted to different conditions with higher frost protection effect. Keywords: frost protection, wind machines, performance test-bed, design, control, PLC DOI: 10.3965/j.ijabe.20160906.1664 Citation: Hu Y G, Liu P, Asante E A, Wu W Y, Li P P. Control system of a performance test-bed for frost protection wind machines. Int J Agric & Biol Eng, 2016; 9(6): 36－43.

A New Mobile Platform (RHyMo) for Smooth Movement on Rugged Terrain

This paper suggests a new performance metric for a mobile platform called as a posture variation index (PVI) to evaluate the smoothness of its movement, which is an important factor to predict undesired oscillations or shocks on a mobile platform while traveling on rugged terrain. The PVI consists of the height and pitch angle variations of center of mass of a mobile platform. By using the PVI, the movements of well-known mobile platforms are systematically analyzed. In order to ensure smooth movement as well as high terrainability on rugged terrain, a new mobile platform (RHyMo) is constructed on the basis of the kinematic and quasi-static analyses. The extensive experiments are carried out by using the RHyMo and the Rocker–Bogie platform on the artificial rugged terrain, which verify that in comparison with the Rocker–Bogie platform, the average and maximum height variations of RHyMo are reduced by 12.72% and 5.96%, respectively. Moreover, the average and maximum pitch angle variations of RHyMo are significantly reduced by 65.87% and 60.53%, respectively. The terrainability of RHyMo against a high step and steep stairs is improved with the help of the track mechanism installed in the front linkage.

Laboratory testing of paddy stripping header mechanism

Stripping is a very popular harvesting concept that continues to challenge designers. The principle of stripping, i.e. removing the seeds from the plant without harvesting the straw. The header loss of the stripping mechanism was greatly influenced by parameters such as crop height, peripheral speed of stripping rotor, forward speed of the machine. Test rig was developed for optimizing these parameters in the laboratory. Test rig consisted of stationary stripping mechanism and movable platform which moves in forward and reverse direction. Stationary stripping mechanism consisted of stripping rotor, stripping elements and adjustable hood. Stripping elements were made of natural rubber having two shapes as slender arrow head and spaced slender arrow head. Movable platform consisted of track, height adjustable platform and crop holders. Track (9×0.7 m) was made of M.S. angle and adjustable platform (4×0.65) m made of plywood. Crop holder (spacing 25×15 cm) with spring arrangement was used for holding crop on the platform. Separate electric motors were provided for power transmission. The experiment was designed with three peripheral speed (14, 17, 20 m/s) of stripping rotor, two forward speeds (1.65 and 2.25 km/h) of the platform and three replications. Stripping rotor height 490 mm from platform and hood height 100 mm from the center of the stripping rotor were kept constant to simulate field crop condition. Testing was done in Rabi season (2015) with paddy variety Ratnagiri-1. The result of trial shows that 2.25 km/h forward speed and 20 m/s peripheral speed of stripping rotor, minimum grain loss was found as 5.56 per cent along with maximum stripping efficiency of 98.12 per cent. The slender arrow head stripping element had better performance with minimum grain loss than that of spaced slender arrow head.

First Results of a GNSS-R Experiment From a Stratospheric Balloon Over Boreal Forests

The empirical results of a global navigation satellite systems reflectometry (GNSS-R) experiment onboard the Balloon EXperiments for University Students (BEXUS) 17 stratospheric balloon performed north of Sweden over boreal forests show that the power of the reflected signals is nearly independent of the platform height for a high coherent integration time T-c = 20 ms. This experimental evidence shows a strong coherent component in the forward scattered signal, as compared with the incoherent component, that allows to be tracked. The bistatic coherent reflectivity is also evaluated as a function of the elevation angle, showing a decrease of similar to 6 dB when the elevation angle increases from 35. to 70 degrees. The received power presents a clearly multimodal behavior, which also suggests that the coherent scattering component may be taking place in different forest elements, i.e., soil, canopy, and through multiple reflections canopy-soil and soil-trunk. This experiment has provided the first GNSS-R data set over boreal forests. The evaluation of these results can be useful for the feasibility study of this technique to perform biomass monitoring that is a key factor to analyze the carbon cycle.

Fin whale seasonal trends in the Pelagos Sanctuary, Mediterranean Sea

Since 2009, a cetacean presence and distribution long-term monitoring study has been ongoing in the Pelagos Sanctuary, a pelagic marine protected area located in the northwestern Mediterranean Sea. One of the objectives of this study is to assess trends in cetacean presence and distribution to achieve good environmental status (GES) of pelagic marine waters. We assessed the density variability of the fin whale (Balaenoptera physalus) in the Pelagos Sanctuary. We used data collected during summer months (Jun–Sep) from 2009 to 2013, along 2 fixed transects crossing the Pelagos Sanctuary, using ferries as platforms of opportunity. We compared 2 un-corrected indexes: the linear encounter rate and density index, computed applying distance sampling methodology to select the most precise method. We also evaluated the effect of environmental covariates (e.g., platform height, Beaufort sea state, wind speed and direction, cloud cover and rain, longitude, latitude) on abundance and density estimation. Finally, we defined an unbiased index and used it to analyze the temporal and spatial variability of fin whale density in the Pelagos Sanctuary. Fin whale density along the 2 transects varied on a yearly basis, with a peak in 2012 and 2013. Variability also occurred on a monthly basis, with a peak during the first half of the season. A longitudinal and a depth gradient were also evident, confirming differences in species displacement in the area. These results are consistent with previous studies, and update current knowledge of species presence in the area. The protocol tested in this work can be easily applied to the other cetacean species inhabiting the Pelagos Sanctuary providing a novel and cost-effective method to assess long-term trends in cetacean distribution and detect incipient changes in species density. © 2015 The Authors. Journal of Wildlife Management published by The Wildlife Society.

Simulating the Effect of Wind on the Performance of Axial Flow Fans in Air-Cooled Steam Condenser Systems

The use of air-cooled steam condensers (ACSCs) is preferred in the chemical and power industry due to their ability to adhere to stringent environmental and water use regulations. ACSC performance is, however, highly dependent on the prevailing wind conditions. Research has shown that the presence of wind reduces the performance of ACSCs. It has been found that cross-winds (wind perpendicular to the longest side of the ACSC) cause distorted inlet flow conditions, particularly at the upstream peripheral fans near the symmetry plane of the ACSC. These fans are subjected to what is referred to as “two-dimensional” wind conditions, which are characterized by flow separation on the upstream edge of the fan inlets. Experimental investigations into inlet flow distortion have simulated these conditions by varying the fan platform height. Low platform heights resulted in higher levels of inlet flow distortion, as also found to exist with high cross-wind velocities. The similarity between platform height and cross-wind velocity is investigated in this study by conducting experimental and numerical investigations into the effect of distorted inlet flow conditions on the performance of various fan configurations (representative of configurations used in the South-African power industry). A correlation between system volumetric effectiveness, platform height, and cross-wind velocity is derived which provides a means to compare platform height and cross-wind velocity effects.

Preliminary Study on the Radar Vegetation Index (RVI) Application to Actual Paddy Fields by ALOS/PALSAR Full-polarimetry SAR Data

Abstract. Kim and van Zyl (2001) proposed a kind of radar vegetation index (RVI). RVI = 4*min(λ1, λ2, λ3) / (λ1 + λ2 + λ3) They modified the equation as follows. (2009) RVI = 8 * σ0hv / (σ0hh + σ0vv +σ0hv ) by L-band full-polarimetric SAR data. They applied it into rice crop and soybean. (Y.Kim, T.Jackson et al., 2012) They compared RVI for L-, C- and X-bands to crop growth data, LAI and NDVI. They found L-band RVI was well correlated with Vegetation Water Content, LAI and NDVI. But the field data were collected by the multifrequency polarimetric scatterometer. The platform height was 4.16 meters from the ground. The author tried to apply the method to actual paddy fields near Tsukuba science city in Japan using ALOS/PALSAR, full-polarimetry L-band SAR data. The staple crop in Eastern Asia is rice and paddy fields are dominant land use. A rice-planting machine comes into wide use in this areas. The young rice plants were bedded regularly ridged line in the paddy fields by the machine. The space between two ridges of rice plants is about 30 cm and the wave length of PALSAR sensor is about 23 cm. Hence the Bragg scattering will appear depending upon the direction of the ridges of paddy fields. Once the Bragg scattering occurs, the backscattering values from the pixels should be very high comparing the surrounding region. Therefore the radar vegetation index (RVI) would be saturated. The RVI did not follow the increasing of vegetation anymore. Japan has launched ALOS-2 satellite and it has PALSAR-2, L-band SAR. Therefore RVI application product by PALSAR-2 will be watched with deep interest.

The effect of simulating a leg-length discrepancy on pelvic position and spinal posture

[Purpose] The purpose of this study was to examine how a leg-length discrepancy contributes to the pelvic position and spinal posture. [Subjects and Methods] A total of 20 subjects (10 males, 10 females) were examined during different artificially created leg-length inequalities (0–4 cm) using a platform. The pelvic tilt and torsion and the sagittal deviation of the spine were measured using the rasterstereographic device formetric 4D. [Results] Changes in platform height led to an increase in pelvic tilt and torsion, while no changes in the spinal posture were found with the different simulated leg-length inequalities. [Conclusion] Our study showed that a leg-length discrepancy may cause pelvic deviation and torsion, but may not lead to kyphosis and lordosis. Therefore, we consider that an artificially created leg-length discrepancy has a greater effect on pelvic position than spine position.

Maximal and sub-maximal functional lifting performance at different platform heights

Introducing valid physical employment tests requires identifying and developing a small number of practical tests that provide broad coverage of physical performance across the full range of job tasks. This study investigated discrete lifting performance across various platform heights reflective of common military lifting tasks. Sixteen Australian Army personnel performed a discrete lifting assessment to maximal lifting capacity (MLC) and maximal acceptable weight of lift (MAWL) at four platform heights between 1.30 and 1.70 m. There were strong correlations between platform height and normalised lifting performance for MLC (R2 = 0.76 ± 0.18, p < 0.05) and MAWL (R2 = 0.73 ± 0.21, p < 0.05). The developed relationship allowed prediction of lifting capacity at one platform height based on lifting capacity at any of the three other heights, with a standard error of < 4.5 kg and < 2.0 kg for MLC and MAWL, respectively.

Marginal masticatory mucosa dimensional changes in immediate post-extractive implants: a 2year prospective cohort study.

The present two-year prospective cohort study was undertaken to evaluate marginal masticatory mucosa dimensional changes around immediate post-extractive implants positioned transgingivally with a non-submerged healing screw. Twenty-one immediate post-extractive implants from 21 patients were enrolled, peri-implant gap was filled with bovine bone mineral, and soft tissue was allowed to heal around a non-submerged healing screw. Post-extractive socket dimension was recorded. Intraoperative (T0) vertical distances: bone margin level (BML) from the bone margin to the implant platform and mucosal margin height (MMH) from marginal mucosa to implant platform were taken; MMH measurement was repeated 4months later (T4). Horizontal mucosal level (HML): from customized stent to marginal mucosa at 0, 4, 12, and 24months postoperatively (T0, T4, T12, T24) and vertical mucosal level (VML): from the stent to marginal mucosa at T4, T12, T24 were registered. One implant failed at 3weeks; in the remaining 20 cases the MMH, coronally positioned with respect to the BML ≅2mm at T0, showed a statistically significant vertical contraction of the mucosa at T4. Other vertical mucosal measurements (VML) did not show further changes over time. HML measures showed a, statistically significant, shrinkage of the mucosa on the transverse plane between T0/T12 and T0/T24 and between T4/T12 and T4/T24. Immediate post-extractive implant inserted transgingivally with a non-submerged healing screw and internal peri-implant gap filled with bovine bone mineral may favor an early and stable peri-implant soft tissue healing over 2years.

Analysis of the chronic lower limb injuries occurrence in step aerobic instructors in relation to their working step class profile: A three year longitudinal prospective study

There is limited information on injury patterns in Step Aerobic Instructors (SAI) who exclusively execute "step" aerobic classes. To record the type and the anatomical position in relation to diagnosis of muscular skeletal injuries in step aerobic instructors. Also, to analyse the days of absence due to chronic injury in relation to weekly working hours, height of the step platform, working experience and working surface and footwear during the step class. The Step Aerobic Instructors Injuries Questionnaire was developed, and then validity and reliability indices were calculated. 63 SAI completed the questionnaire. For the statistical analysis of the data, the method used was the analysis of frequencies, the non-parametric test χ<formula>^{2}</formula> (chi square distribution), correlation and linear and logistic regressions analysis from the SPSS statistical package. 63 SAI reported 115 injuries that required more than 2 days absence from step aerobic classes. The chronic lower extremity injuries were 73.5%, with the leg pain, the anterior knee pain, the plantar tendinopathy and the Achilles tendinopathy being most common overuse syndromes. The working hours, the platform height, the years of aerobic dance seem to affect the days of absence due to chronic lower limb injury occurrence in SAI.

Statistical Analysis for Platform Height Ratio of Horizontal Components in Bedrock Seismic Oscillation Velocity Response Spectrum

Based on the strong ground motion records of the bedrock, the overall feature of ratio (H1/H2) of the platform height of two horizontal components in velocity response spectrum was analyzed. The results show that: (1) The platform height values of two horizontal components are different from each other; (2) H1/H2 decreases with the increasing of earthquake magnitude, decreases with the increasing of epicenter distance, and tends to be 1 in far field.

The formation of beaches on shore platforms in microtidal environments

ABSTRACTBeaches are common features of many rocky shorelines and can be considered to be constrained by the underlying geology. In mesotidal to macrotidal areas the slope of the substrate and sediment supply are the primary factors in constraining the size and development of beaches on shore platforms. In microtidal settings it is not known if these factors are wholly responsible for determining the presence of beaches on shore platforms, nor the contribution of other factors such as hydrodynamics. The microtidal coast of Victoria, Australia, is surveyed in this study in order to quantify the morphological boundary conditions that constrain beach development on semi‐horizontal shore platforms. An ample sediment supply indicates that the underlying geology is controlling the presence and absence of beaches. Where beaches occur they always overlie a rock ramp which is the steepest part of the platform. The two most important morphological constraints were platform width and height both of which significantly correlated with beach volume. An elevational threshold exists at just over +1.0 m where beaches cannot accumulate. Below this threshold, platform width appears to be the principle constraining factor in beach accumulation. An evolutionary model is inferred which suggests that dissipation of wave energy associated with platform widening plays an important role in allowing beaches to accumulate. The model suggests beaches on platforms will be particularly sensitive to sea level rise. Copyright © 2014 John Wiley &amp; Sons, Ltd.

&lt;b&gt;Acute adjustments of heart rate and oxygen consuption in an experimental protocol of step training with diferent combinations of platform height and musical rhythms&lt;/b&gt; - doi: 10.4025/actascihealthsci.v35i2.11669

The aim of this study was to investigate adaptations acute heart rate (HR) and oxygen consumption (VO2) in an experimental protocol of step training with different combinations of platform height (15.2, 20.3 and 25.4 cm) and musical rhythms (125, 135 and 145 bpm). Thirty-five women were randomly selected, (mean ± DP) aged 21.6 ± 1.8 years, body weight of 57.8 ± 8.2 kg, height of 162.6 ± 6.8 cm, body mass index of 21.8 ± 2.5 kg m-2 and fat percentage (% Fat) of 24.8 ± 4.4%, with at least six months experience in step training sessions, and a frequency of at least two days a week. Techniques of descriptive and inferential statistics were employed. A significant difference was detected for the HR and VO2 in relation to the increase in step platform height and in musical rhythm for all the combinations, except for three situations. From the obtained results, we can infer that the cardiovascular and metabolic responses increase or decrease according to the musical rhythm and/or platform height.

Influence of the Ultimate Torsion on the Geometry of Dental Implants

This study evaluated the profile of implants subjected to torsion test. Four types of implants (Conexão®) were analyzed: Master Porous (MP - external hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm), Master Screw (MS - external hexagon, cylindrical, machined implants; 11.5 X 3.75 mm), Conect Conic (CC - external hexagon, cylindrical, machined implants; 11.5 X 3.5 mm) and Master Conect AR (CA - internal hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm). The Nikon® model C profile projector was used for the analysis before and after torsion test with a Mackena® model MK-20XX digital torque meter. The measures analyzed in the profile of implants were: diameter and height of the platform, diameter of the screw/platform connection, angle of the screw/platform connection, external diameter, internal diameter, thread pitch, height and length of the thread. Statistical analysis was performed using ANOVA and Tukey test at 5% significance level. The torsion test caused a visible deformity on the external implant profile. There was a statistical difference among the implants before and after torsion (p<0.05) for the variables: platform diameter, platform height, diameter of the screw/platform connection and length. Changes were observed in platform height of CC and CA, fracture of CA implants, fracture of the MP and MS assembler/connectors, and internal thread stripping of CC. Thus, it was concluded that excessive or some unadvised torque by the manufacturer can lead to changes in different geometric measurements of implants.

계단 등반을 위한 신개념 로봇 플랫폼의 기구변수 최적화

Stair climbing is one of critical issues for field robots to widen applicable areas. This paper presents optimal design on kinematic parameters of a new robotic platform for stair climbing. The robotic platform climbs various stairs by body-flip locomotion with caterpillar type main platform. Kinematic parameters such as platform length, platform height, and caterpillar rotation speed are optimized to maximize stair-climbing stability. Three types of stairs are used to simulate typical user conditions. The optimal design process is conducted based on Taguchi methodology, and resulting parameters with optimized objective function are presented. In near future, a prototype is assembled for real environment testing.

Determination of the amount of leg length inequality that alters spinal posture in healthy subjects using rasterstereography

Leg length inequalities (LLIs) can result in an increased energy consumption, abnormal gait or osteoarthritis of the hip. In a previous study we simulated different LLIs of up to 15 mm and evaluated their effects on the pelvic position and spinal posture. We found a correlation between LLIs and resulting changes of the pelvic position. Despite suggestions in the literature we were not able to detect significant changes of the spinal posture. Therefore, the purpose of this study was to determine the amount of LLI that would in fact alter the spinal posture. The subjects were placed on a simulation platform, whose height could be precisely controlled by the measuring device, to simulate different LLIs of up to 20 mm. For LLIs >20 mm, additional precision-cut wooden blocks were used under one foot. After an adaptation period the resulting changes of the pelvis and spine were measured with a rasterstereographic device. We found a significant correlation between platform height changes and changes of the pelvic position. The frontal spinal parameters surface rotation and lateral deviation changed significantly when simulating differences greater than 20 mm. No changes of the sagittal spinal curvature were measured, however, a trend to decreasing kyphotic angles was noted. Our study has shown for the first time that LLIs >20 mm will lead to significant changes in the spinal posture of healthy test subjects. However, these changes were only found in frontal (surface rotation and lateral flexion) spinal parameters, but not in sagittal parameters. Here for the kyphotic angle only a tendency to decreasing angles was noted. We have also found a significant correlation between different leg lengths and changes of the pelvic position. Further, females and males seem to react in the same way to LLIs.

Application of Differential Evolution Algorithm for Calibrating Design Seismic Response Spectra

Differential evolution (DE) algorithm is a heuristic approach that has a great ability to solve complex optimization and converges faster and with more certainty than many other acclaimed global optimization methods. In this paper, DE algorithm is applied to calibrate design seismic response spectra, the basic idea is that design response spectra and calculated response spectra are defined as objective function of characteristic parameters, the first turning point, the second turning point (characteristic period), the platform height and the attenuation index, of design response spectra, and the characteristic parameters are obtained by minimizing the objective function. Three pieces of the calculated response spectra for one real are calibrated as an application example. The obtained results demonstrate the effectiveness and efficiency of the proposed method.