Abstract Isokinetic normative data can be invaluable in identifying an individual’s strengths and weaknesses, and thus lead to a more effective use of the individual’s time to minimise or overcome his weaknesses while maintaining or improving existing strength. However, visual feedback (VF) may significantly affect the result of isokinetic testing, resulting in erroneous conclusions if not accounted for. Additionally, the previous use of VF to obtain increased strength values has resulted in inconsistent findings. The purpose of this study was to examine the effect of VF on concentric and eccentric knee extensor peak torque. Twenty-two sedentary, college-aged male and female volunteers were assigned to either Group 1 (n = 11) or Group 2 (n = 11) to either perform knee extensor concentric-eccentric (con-ecc) isokinetic testing with VF or without VF (no-VF) using a crossover method. After a one-week rest, the two groups underwent knee extensor con-ecc isokinetic testing using the alternative testing condition. Each test consisted of five maximal knee extensor con-ecc isokinetic testing contractions at 60° per second on the Cybex Norm system. The data indicated significant (p < 0.05) differences in the concentric peak torque of Group 1, Group 2 and Combined Group following VF when compared to no-VF. The eccentric peak torque of Group 1, Group 2 and Combined Group was found not to be significantly different following VF when compared to no-VF. Further, no significant interaction effect as a result of the different groups was found. Visual feedback of torque output can improve maximum voluntary concentric contraction in isokinetic dynamometry, but not maximum voluntary eccentric contraction. It is thus recommended that VF should be consistently provided during isokinetic testing, since it can also be used to help detect and correct errors in performance as well as derive reinforcement from correct performances.

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Background: Research has displayed a strong relationship between lower body strength and power, both in eccentric-concentric and concentric only exercises, in male soccer players. However the relationship between different types of squats and sprint performance has not been studied thoroughly in young male soccer players. Aim: The aim of the study was to investigate the relationship between sprint performance and power output in different squat variations in young male soccer players. Methods: Eleven young male soccer players, 17-19 years old, were tested in 1 repetition maximum (1RM) squat (S), 1RM concentric squat (CS) and in 5m, 10m, 15m and 30m sprint performance. Power testing in S and CS were performed at 30%, 50% and 70% of 1RM and registered as absolute power (W) and as power relative to body weight (W/kg). Results of the power output in S and CS were correlated with sprint performances. Correlations of rs ≥0.6 were considered to indicate a strong relationship. Results: There were strong correlations (rs = -0.61 to -0.68) between CS power output at 50% of 1RM, relative to body weight (W/kg), and all the sprint distances. S power output at 50% of 1RM, relative to body weight (W/kg), showed strong correlations (rs = -0.64 to -0.67) to 5m, 10m and 15m sprint. The only absolute power output (W) value to strongly correlate (rs = -0.62) with sprint performance was S at 50% of 1RM and 5m sprint. Conclusion: Both S and CS performance showed strong correlations with sprint start performance in young male soccer players. In conflict with previous research, this study showed a stronger correlation between CS and 30m sprint performance than S did. The results support previous findings that strength and power divided by body weight are stronger associated with sprint performance than absolute measures are. Both S and CS should be performed in the general strength training program to improve maximal strength and power, and thereby enhance soccer performance.

The hypothesis. We supposed the fatigue and its residual phenomena generated by eccentric concentric load to have a different effect on the changes in vegetative indices during exercise of high aerobic intensity in particular. The aim of the research was to establish the effect of eccentric concentric pre-load on the changes in vegetative indices during exercise of high intensity. The tasks set were as follows: 1. To estimate the residual effect of eccentric pre-load on the changes in vegetative indices during exercise of high intensity. 2. To estimate the residual effect of eccentric-concentric pre-load on the changes in vegetative indices during exercise of high intensity. 3. To compare the residual effect of eccentric and eccentric-concentric pre-load on the vegetative indices, biochemical indices of blood during exercise of high intensity. The subjects were 9 unsportsman persons, who gave their informed consent to take part in the experiments within the present study. They were distributed to two eksperimental groups. The first group carried out eccentric pre-load and the second group carried out eccentric-concentric pre-load. The methods used were as follows: changes in the values of VO2, VCO2, heart rate (HR) and Ve indices of the subjects were established applying the test of continuously increased load and the test of constant load when pedalling the veloergometer. After testing blood of the subjects to establish lactate and Creatin-Kinase (CK) concentration in... [to full text]

Gibbsite scale growth in pipe fittings is a major problem for an alumina refinery. A recent investigation into the scale growth mechanism at an alumina refinery found almost 60 % more scale growth in a reducer when compared with the connecting straight pipe sections for similar flow conditions. Scale growth occurs where liquor (supersaturated solutions) come in contact with solid surfaces and it is affected by the liquor flow velocity besides other physical and chemical parameters. The present work is dedicated to study the hydro-dynamical aspects of the mechanism of scale growth. In particular, the role of the phenomenon of turbulent bursting, stream wise and cross stream fluctuating velocity components (Ux and Uy) was investigated as the flow moves through the reducer. Particle Image Velocimetry (PIV) technique was used to get a full view of the reducer and the readings close-to-the-wall of the reducer at Reynolds number of 27,000 and 44,000 upstream which corresponds to Reynolds number of 41,500 and 66,000 downstream of the reducer respectively. The results showed an increase in cross stream and a decrease in magnitude of stream wise fluctuating velocity components, whereby we presume that the increased cross stream fluctuating velocity component increases the frequency of impacts of the scaling particles on the wall thus initiating excessive scale growth in the reducer when compared with the connecting straight pipe sections, for similar flow conditions.

This study discusses the three-dimensional refraction of progressive wave trains propagating over a bottom of circular concentric contours and the results are expressed in a polar coordinate. First, a general differential formulation of refraction is derived via three different methods: by transferring from its original Cartesian form to the polar coordinate, by applying the Fermat¡¦s principle in polar coordinate, and by applying the conservation of waves in polar coordinate. All three approaches give the same governing equation; hence, its correctness is verified. Based on this governing equation, the wave ray, the phase function, the constant phase line, and the refraction coefficient are all determined. In the present refraction problem for an originally uniform wave train propagating over a bottom of circular concentric contours, a few special features, including the cusps of constant phase lines due to the effect of bottom, and the envelope composed of these cusps, are present. All these refraction properties can be expressed in terms of both a snapshot and a time evolution of constant phase lines. In the lee side of the shoal, there exists a sheltered zone that is enclosed by the envelope of the cusps. In this zone, wave rays intersect and the corresponding caustic problem arises, and all possible combinations of intersecting rays are also specifically described in this study. The difficulty of classical ray theory for the caustic problem is overcome and the caustic phenomenon and its refraction coefficients are determined explicitly in this study.

<p> The Burgess concentric zone model was assessed using census data for Chicago community areas in 1940. Burgess' model implies that the lower-income residents live in the center of the city while upper-income residents live on the periphery of the city. Using occupation as a determinant of socio-economic status, location quotients were calculated to determine patterns of residential differientiation. It was found that upper-income residents did indeed reside in the peripheral areas of the city, but they also lived near the central business district. The lakefront amenities were the primary reason for this residential pattern. Many low income residents lived near the center of the city, but many were also found to live in the suburbs due to industrial decentralization. Thus, the lakefront amenities and the suburban industries are the primary causes of the distortion of the Burgess model. However, this distortion does not suggest the Burgess zonal hypothesis is inaccurate. The discrepancies may be attributable to the uneven growth of cities through the "filtering" process. </p> / Thesis / Bachelor of Arts (BA)

The performance of an acoustic filter (or muffler) is measured in terms of one of the following parameters: Insertion Loss (IL), Level difference (LD) and Transmission loss (TL). All these three parameters may be evaluated in terms of the four-pole or transfer matrix parameters. Appropriate experimental setups have been designed and developed and practical considerations are described. Measured values of TL are compared with the analytically predicted values. It is shown that the Two-Source-Location method is relatively the best. To start with, the matrizant analysis of conical concentric tube resonators is validated experimentally. The effect of mean flow is investigated. The experimental setup is specially designed to measure the pressure transfer function across the test muffler. It is shown that there is reasonably good agreement between the predicted values of the transfer function and the measured ones for incompressible mean flow as well as stationary medium. To measure insertion loss of muffler, one needs to calculate the source impedance. The internal impedance of a sound source can be measured using direct or indirect methods. The four-load SPL measurement method is one such indirect method wherein there are three nonlinear equations in terms of two unknowns which makes one of the equations redundant. This leads to erroneous results. To overcome this inherent weakness, two alternatives multi-load methods have been offered in the literature; namely, the least squares and the direct least squares method, to analyze the measured data used for four (or more) different loads. These two methods produce better results than the four-load SPL measurement method used earlier. These measurement methods have been tested on a loudspeaker to measure its source impedance and the results are validated with a known additional acoustic load. Simple expansion chambers, the simplest of the muffler configurations, have very limited practical application due to the presence of periodic troughs in the transmission loss (TL) spectrum which drastically lower the overall TL of the muffler. Many of the present days automobile exhaust systems make use of the extended tube mufflers, often with perforated ducts because of their low back pressure and good acoustic performance. Tuned extended inlet and outlet can be designed to nullify three-fourths of these troughs, making use of the plane wave theory. However, these cancellations would not occur unless one altered the geometric lengths for the extended tube and perforated tube resonators in order to incorporate the effect of the evanescent higher-order modes (multidimensional effect) through end corrections or lumped inertance approximation at the area discontinuities or junctions. This is investigated here experimentally as well as numerically (through use of 3-D FEM software) for a moving medium as well as stationary medium. The effect of temperature on the end corrections is also investigated. These tuned extended-tube chambers, however, suffer from the disadvantages of high back pressure and aerodynamic noise generation at the area discontinuities. These two disadvantages can be overcome by means of a perforated bridge between the extended inlet and the extended outlet. One dimensional control volume approach is used to analyze this muffler configuration. It is validated experimentally making use of the two source-location method, which is proven to be the best method available to us. It is thus shown that the inertance of holes plays a role similar to the lumped inertance generated by evanescent 3-D modes at the terminations of the quarter wave resonators in the case of the double-tuned extended tube chambers. The effect of mean flow is also investigated. The resultant transfer matrix is then used to carry out a systematic parametric study in order to arrive at empirical expressions for the differential lengths as well as the end corrections. Thus, an extended concentric tube resonator can be tuned such that the first three troughs that characterize the corresponding simple chamber transmission loss (TL) curve may be eliminated making use of the proposed procedure. In fact, the entire TL curve at low and medium frequencies may be substantially lifted, making the tuned extended concentric tube resonator a viable design option.

Abstract The main outline of this paper is divided into six chapters, as follows. Introduction of the first chapter, respectively, describe the motive of writing the purpose of research methods , the main terms and concepts related to a introduced. Chapter II, "the type of juvenile law and basic functional theory", first of all, mainly to clarify the function of model juvenile law and juvenile law related to the basis of a preliminary study to explore the rationale; followed, especially on Taiwan's 1997 amendments to the creation of juvenile law the "concentric circle theory" and the juvenile law system thinking interpretation of it. Chapter III "juvenile protection and international norms", is the first on juvenile protection and the formation of international norms slightly introduction, followed by the current international juvenile most countries signed the protection of international instruments "Convention on the Rights of the Child", "juvenile justice Standard Rules (the Beijing Rules) "," Protection of Juveniles Deprived of their Liberty Rules "and" guidelines for the Prevention of Juvenile Delinquency (Riyadh Guidelines), "notes one by one; Finally, in 2008 occurred in Taiwan's Kaohsiung port by juvenile probation girls shift supervisor incident Cases of view of international norms in our country to implement it or not. Chapter IV, "Taiwan and Japan's juvenile law amending the law History and Trends" to the two most recent content of amending the law (namely, in 2006 the draft amendment of Taiwan's juvenile law and juvenile law in 2000 to amend the content of Japan) for the scene, combined with the theory and practical view, discusses the trend of juvenile law. Chapter V "Taiwan and with Japan's juvenile law more", it has since juvenile law to distinguish between the two countries with the specific provisions of the same comparative study, although the former is the same provisions, but in different field of customs and people, the respective lead drawing a lot of practical life; the latter is looking forward to learning as the domain from the start, trying to inspire a new style of juvenile law. Finally, Chapter VI "Conclusions", in order for both theory and practice in this article, so on Taiwan's current practice of juvenile law to make a benign-depth criticism, as the experience of corroborative evidence, and of amending the law.

To examine the effect of acute beetroot juice supplementation on the rate of fatigue as measured by changes in peak torque. Placebo-controlled, double-blind, cross-over study, 35 recreationally active subjects consumed beetroot (BR) juice or black currant juice (PL) 12 and 2.5 hours before the exercise procedure. Peak torque was measured on the BIODEX dynamometer by performing 50, maximal effort, concentric knee extensions at 90°/s. Blood pressure (BP) was recorded before and after exercise. No significant difference between BR and PL in the rate of fatigue measured by change in peak torque. By stage 3, subjects retained 87.6±6.9% of strength with BR and 86.7±6.3% with PL (p= 0.363). Stages 10 was as follows: BR 47.9±12.6 vs. PL 46.9±12.9% (p= 0.419). The rate of work fatigue showed no significant differences. By stage 4, mean percent work fatigue showed 20.6±9% with BR and 21.8±10.1% with PL (p= 0.224). Stage 10 was as follows: BR 52.5±12.6% vs. PL 53.2±13% (p= 0.571). Post-exercise diastolic BP (BR: 67.2±9.8 vs. PL: 64.5±7.9mmHg, p= 0.039) and MAP (BR: 91.6±9.3 vs. PL: 88.8±8.2mmHg, p= 0.011) were higher with BR supplementation. Acute bouts of beetroot juice supplementation had no significant effect on knee extensor muscle fatigue measured during isokinetic contractions