Constant Running Research Articles

Exergetic Sustainability Indicators as a Tool in Commercial Aircraft: A Case Study for a Turbofan Engine

This paper focuses on the exergetic sustainability indicators of a medium-range commercial aircraft engine for constant reference environment and ground running conditions. First, a detailed exergy analysis of turbofan engine have been performed based on engine test cell parameters. Starting from the sustainability considerations and the second law of the thermodynamics, the paper presents six exergy-based sustainability indicators. The indicators of the turbofan engine developed here in conjunction with exergetic analysis and sustainable development are exergy efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy rate, environmental effect factor, and exergetic sustainability index. The investigated sustainable indicators have been calculated by using exergy analysis outputs for aircraft ground running condition. Results from this study show that values of exergy efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy rate, environmental effect factor, and exergetic sustainability index of investigated turbofan engine are found to be 0.315, 0.685, 0.408, 0, 2.174, and 0.460, respectively. These parameters are expected to quantify how the turbofan engine and aircraft become more environmentally benign and sustainable.

Analysis of bifurcation and stability for a tractor semi-trailer in planar motion

This paper is intended for bifurcation analysis of a nonlinear tractor semi-trailer vehicle model in planar motion and for investigating its stability under constant running conditions. Bifurcation analysis shows that bifurcation diagrams of a tractor semi-trailer are quite different from those of a single-unit vehicle. Some instability phenomena of the vehicle system such as jackknifing, sideslip, and spinning are explained by correlating them with the behaviour in the neighbourhood of unstable fixed points based on analysis of eigenvectors, phase trajectories, and status of lateral tyre force saturation. It is also found that yaw planar instability of a tractor semi-trailer is caused by lateral tyre force saturation of the tractor's rear axles and/or the trailer's axles. Moreover, the stability region in the state space is demarcated, and a stability index for evaluating size of the stability region in a feasible domain is proposed. Yaw stability under constant driving conditions is analysed by using the proposed stability index.

Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies

The BICEP2 collaboration has reported a strong B mode signal in the CMB polarization, which is well fit by a tensor-to-scalar ratio of r ≃ 0.2. This is greater than the upper limit r < 0.11 obtained from the temperature anisotropies under the assumption of a constant scalar spectral index ns. This discrepancy can be reduced once the statistical error and the contamination from polarized dust are accounted for. If however a large value for r will be confirmed, it will need to be reconciled with the temperature anisotropies data. The most advocated explanation involves a variation of ns with scales (denoted as running) that has a magnitude significantly greater than the generic slow roll predictions. We instead study the possibility that the large scale temperature anisotropies are not enhanced because of a suppression of the scalar power at large scales. Such a situation can be achieved for instance by a sudden change of the speed of the inflaton (by about 14%), and we show that it fits the temperature anisotropies and polarization data considerably better than a constant running (its χ2 improves by ∼ 7.5 over that of the constant running, at the cost of one more parameter). We also consider the possibility that the large scale temperature fluctuations are suppressed by an anti-correlation between tensor and scalar modes. Unfortunately, while such effect does affect the temperature fluctuations at large scales, it does not affect the temperature power spectrum and cannot, therefore, help in reconciling a large value of r with the limits from temperature fluctuations.

Complex signal analysis for wind turbine planetary gearbox fault diagnosis via iterative atomic decomposition thresholding

The vibration signals from complex structures such as wind turbine (WT) planetary gearboxes are intricate. Reliable analysis of such signals is the key to success in fault detection and diagnosis for complex structures. The recently proposed iterative atomic decomposition thresholding (IADT) method has shown to be effective in extracting true constituent components of complicated signals and in suppressing background noise interferences. In this study, such properties of the IADT are exploited to analyze and extract the target signal components from complex signals with a focus on WT planetary gearboxes under constant running conditions. Fault diagnosis for WT planetary gearboxes has been a very important yet challenging issue due to their harsh working conditions and complex structures. Planetary gearbox fault diagnosis relies on detecting the presence of gear characteristic frequencies or monitoring their magnitude changes. However, a planetary gearbox vibration signal is a mixture of multiple complex components due to the unique structure, complex kinetics and background noise. As such, the IADT is applied to enhance the gear characteristic frequencies of interest, and thereby diagnose gear faults. Considering the spectral properties of planetary gearbox vibration signals, we propose to use Fourier dictionary in the IADT so as to match the harmonic waves in frequency domain and pinpoint the gear fault characteristic frequency. To reduce computing time and better target at more relevant signal components, we also suggest a criterion to estimate the number of sparse components to be used by the IADT. The performance of the proposed approach in planetary gearbox fault diagnosis has been evaluated through analyzing the numerically simulated, lab experimental and on-site collected signals. The results show that both localized and distributed gear faults, both the sun and planet gear faults, can be diagnosed successfully.

Changes in Gait During Constant Pace Treadmill Running

Treadmills are often used by runners when weather conditions are adverse or a specific training effect is desired. Athletes might respond to fatigue differently when running on a treadmill compared with overground conditions, where pace is typically more variable. The purpose of this study was to measure changes in gait parameters over the course of a 10-km treadmill run. Fifteen male competitive runners ran at a constant pace for 10 km at 103% of season's best time on an instrumented treadmill with in-dwelling force plates, and data were analyzed at 5 distances. Kinematic data were derived from high-speed videography and results compared between the early and late stages. Before halfway, step length increased and cadence decreased, whereas during the latter stages, there were significant decreases in impulse and maximum force. Contact time decreased and flight time increased continually, but otherwise most gait variables did not change. The changes in contact and flight times suggested that athletes altered their gait so that more time was spent airborne to allow the treadmill to pass under them. In general, however, the runners maintained their techniques throughout the run. Constant pace treadmill running might therefore be useful with the aim of running for a particular distance and speed with a consistent technique unaffected by factors such as gradient or fatigue. However, the increase in flight time might have aided the runners because of the nature of treadmill running, and athletes and coaches should note that this training effect is impractical during overground running.

Driving With Hemianopia: III. Detection of Stationary and Approaching Pedestrians in a Simulator

To compare blind-side detection performance of drivers with homonymous hemianopia (HH) for stationary and approaching pedestrians, initially appearing at small (4°) or large (14°) eccentricities in a driving simulator. While the stationary pedestrians did not represent an imminent threat, as their eccentricity increased rapidly as the vehicle advanced, the approaching pedestrians maintained a collision course with approximately constant eccentricity, walking or running, toward the travel lane as if to cross. Twelve participants with complete HH and without spatial neglect pressed the horn whenever they detected a pedestrian while driving along predetermined routes in two driving simulator sessions. Miss rates and reaction times were analyzed for 52 stationary and 52 approaching pedestrians. Miss rates were higher and reaction times longer on the blind than the seeing side (P < 0.01). On the blind side, miss rates were lower for approaching than stationary pedestrians (16% vs. 29%, P = 0.01), especially at larger eccentricities (20% vs. 54%, P = 0.005), but reaction times for approaching pedestrians were longer (1.72 vs. 1.41 seconds; P = 0.03). Overall, the proportion of potential blind-side collisions (missed and late responses) was not different for the two paradigms (41% vs. 35%, P = 0.48), and significantly higher than for the seeing side (3%, P = 0.002). In a realistic pedestrian detection task, drivers with HH exhibited significant blind-side detection deficits. Even when approaching pedestrians were detected, responses were often too late to avoid a potential collision.

筋張力の動力学的変換率および発揮負担度からみた定速走における 支持脚筋群の動的特徴

筋張力の動力学的変換率および発揮負担度からみた定速走における 支持脚筋群の動的特徴

収縮様式を考慮した定速走動作における支持脚筋群の動力学的な役割

本研究では，定速の走動作における支持脚筋群について，その収縮様式を考慮した役割を明らかにすることを目的とした．踵接地タイプのランナー12名を被験者とした速度3.3[m/s]の走動作に対して，筋骨格モデルにより推定した支持脚筋張力，および全身の運動方程式を用いて，各筋の収縮様式別の筋張力による身体重心加速度に対する貢献を算出した．その結果，下腿三頭筋は，制動局面においては主に伸張性，推進局面においては主に短縮性収縮による筋張力によって，身体の支持および推進に大きく貢献することが明らかとなった．また，大腿直筋は支持期を通して伸張性，広筋群は制動局面においては伸張性，推進局面においては短縮性収縮による筋張力によって，身体の支持および制動の役割を担っていることがわかった．さらに，背屈筋群は，伸張性収縮による筋張力によって，踵接地後の衝撃を緩和していることが明らかとなった．

The economics and engineering of bus stops: Spacing, design and congestion

This paper re-considers the problem of choosing the number of bus stops along urban routes, first by estimating the probability of stopping in low demand markets, and second by analysing the interplay between bus stop size, bus running speed, spacing and congestion in high demand markets. A comprehensive review of the theory and practice on the location and spacing of bus stops is presented. Using empirical data from Sydney, Australia, we show that the widely used Poisson model overestimates the probability of stopping in an on-call bus stopping regime, and consequently underestimates the optimal number of bus stops that should be designed. For fixed-stop services, we show that bus running speed, frequency and dwell time are crucial to determining the relationship between bus stop spacing and demand, with bus stop congestion in the form of queuing delays playing a key role. In particular, we find that bus stop spacing should be decreased if demand increases at a constant bus running speed; however, if both bus running speed and the speed of the passenger boarding process increase, then the distance between bus stops should be kept long even at high demand levels, a result that is consistent with the implementation of Bus Rapid Transit (BRT) systems that feature high bus running speeds and long distances between stops relative to conventional bus services.

The Speed and Position Control Method for Constant Magnetism Synchronous Motors Running at Low Speed

In the rotor field oriented vector control system, the use of permanent magnet synchronous motor voltage equations and flux equations derived PMSM position and speed estimation method has its unique advantages, The advantage of this approach is to calculate a simple, fast dynamic response, and easy to implement. However, when permanent magnet synchronous motor running at low speed, back EMF would be very small, which can not guarantee the accuracy of estimates. In addition, the position and speed estimation parameters of permanent magnet synchronous motor is largely in dependence on the running status of permanent magnet synchronous motor ,and vulnerable to temperature and magnetic saturation phenomena.All of these elements will lead to error increase. In order to solve the problem of inaccuracy in parameters estimation of motors at low speed, PI controller is introduced to obtain the rotor speed information, and then make up for deficiencies in the estimation algorithm. At the same time, this method can be applied to achieve smooth switching of high speed switching of the motor.

4E analysis and multi-objective optimization of CCHP using MOPSOA

Thermal modeling and optimal design of combined cooling, heating, and power generation system are presented in this article. Selecting the type and number of prime movers, their nominal power and operational strategy, the heating capacity of backup boiler and storage tank, the cooling capacity of electrical and absorption chillers as well as electric cooling ratio (the ratio of electrical chiller capacity to the demand cooling capacity) were considered as nine design parameters. Three types of prime movers including gas turbine, diesel engine, and gas engine were studied in this article. Multi-objective particle swarm optimization algorithm was applied to obtain the maximum actual annual benefit and exergy efficiency simultaneously. Actual annual benefit included the energy, economy, and environmental parameters, therefore with adding exergy parameters, 4 E analysis of combined cooling, heating, and power system was performed. The combined cooling, heating, and power system could run in two operation modes, named economical and electricity tracking modes. In the former case, it was allowed to sell the excess electricity to the network and in the latter, it was not allowed to sell the excess electricity to the grid. It was observed that actual annual benefit for the gas engine was higher than two other cases in economical mode. In electricity tracking mode, the gas engine and gas turbine were more profitable. In addition, the trends of optimum values of design parameters versus actual annual benefit and exergy efficiency in economical mode were investigated and the results were presented. Finally, the results of applying the assumptions of constant and variable running load of prime movers during a year were compared.

On Models of Nonlinear Evolution Paths in Adiabatic Quantum Algorithms

In this paper, we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimensional projector Hamiltonians on the corresponding ground state. If the overlap between the initial state and final state of the quantum system is not equal to zero, both of these models can provide a constant time speedup over the usual adiabatic algorithms by increasing some another corresponding “complexity". But when the initial state has a zero overlap with the solution state in the problem, the second model leads to an infinite time complexity of the algorithm for whatever interpolating functions being applied while the first one can still provide a constant running time. However, inspired by a related reference, a variant of the first model can be constructed which also fails for the problem when the overlap is exactly equal to zero if we want to make up the “intrinsic" fault of the second model — an increase in energy. Two concrete theorems are given to serve as explanations why neither of these two models can improve the usual adiabatic evolution algorithms for the phenomenon above. These just tell us what should be noted when using certain nonlinear evolution paths in adiabatic quantum algorithms for some special kind of problems.

J231014 定速走におけるシューズソールの動力学的機能の定量化([J231]スポーツ工学)

The purpose of this study was to quantify the functional role of compressive characteristics of shoes sole by combining a finite-truss-element shoe model and equation of whole-body motion. The equation of the shoe sole deformation was developed by modeling sole as a construction of truss elements with nonlinear spring and damper properties. The coefficients of the properties were identified from impact test by using an impact device consisting of accelerometer and arm with an impactor. The equation of whole-body motion was derived by modeling the human body as a system of 15-rigid linked segments with consideration of DOF in joint constraint axes and of changes in lengths of modeled segments. Dynamic contributions of the support leg joint torques, which were caused by the elastic and viscous property of the shoes sole, to the generation of whole-body CG' s acceleration were calculated under constant running speed conditions. The results in this study indicate that 1) the plantar flexion torque about the ankle caused by the elastic property of the forepart of shoes sole contributes to the horizontal and vertical acceleration of whole-body's CG, and 2) the extension torque of the knee caused by the elastic property of shoe sole contributes to the horizontal deceleration and the vertical acceleration of whole-body CG.

Is there a ‘light’ and ‘dark’ side to British counterterrorism?

Great Britain has a long and varied experience of dealing with terrorism, spanning some 400 years from the time of Guy Fawkes. This experience ranges from dealing with small anarchist groups in the 1800s, full counter-insurgency campaigns fought during the withdrawal from Empire in the 1940s and 1950s and the long running efforts to stop violence associated with Northern Ireland. Such a varied nature of threats means that the British response has been continually adapted at policy, legislative and policing levels. Despite this adaptation and change, there seems to be a constant theme running throughout the history of British counterterrorism.

Changes of rat respiratory and locomotory muscles during aerobic exercise training in continuous and interval regimens

Male Wistar rats were treadmill-trained for 8 weeks using one of the two regimens: with the constant running speed or with alternating high-speed and low-speed intervals. Both training regimens led to an increase of rat aerobic capacities and to a higher citrate synthase activity in the medial head of gastrocnemius muscle. No differences between the effects of two training regimens were observed. However, in contrast to constant-speed training the interval one resulted in myocardium hypertrophy and also in less pronounced changes in diaphragm muscle, such as slow-direction shift of myosin phenotype and reduction of muscle fiber cross-sectional area. Neither of the training regimens had an effect on corticosterone and thyroid hormones levels in rat blood, whereas the interval training resulted in a higher level of testosterone. Anabolic influence of testosterone during interval aerobic training may be favorable for heart hemodynamic capacity and force characteristics of the diaphragm.

Upgrade of a large scale oxidation ditch plant

A large-scale oxidation ditch (OD) plant had been upgraded by modifying the aeration and stirring technique of the ditches. Through upgrade, surface turbine aerators have been installed together with the existing aeration rotors. A turbulent stirring was created by the addition of the new turbine aerators, while the recirculation motion achieved by the original rotors. The two aeration techniques (turbulent stirring and recirculation motion) were operated at different ratios ranging from 0.0–1.0. As a result, by operating the turbulent stirring and gradual dispensing with recirculation motion, the system version gradually converted from an OD to a conventional activated sludge. Firstly, the gradual conversion from recirculation motion to turbulent stirring was performed under constant oxygenation level (DO) approximately 1.0 mg/L. Secondly; the turbulent stirring was increased with constant running of recirculation motion associated with gradual increase of DO level up to 2.5 mg/L. The effect of aeration and stirring on removal efficiency, sludge production, and sludge settleability has been revealed. It was found that turbine aerators could be added successfully inside ODs to increase the whole system efficiency. Firstly, at constant DO level, under same aeration power, turbulent stirring increased the removal efficiency of COD from 65 to 74%. The observed sludge yield (Yobs) came down from 0.31 to 0.25 gm volatile suspended solids (VSS)/gm BOD. Furthermore, the sludge settleability was enhanced from SVI = 137 to 115. Secondly, increased DO level with the new turbulent stirring, increased removal efficiency of COD from 65 to 95%. Moreover, the system achieved a nitrification efficiency of 70%. Finally, the sludge settleability was improved from SVI = 164 to 92 with minimum sludge yield.

The effects of exercise modality on the incidence of plateau at

The purpose of this study was to determine the effect of exercise modality on the incidence of plateau at VO2max. Twelve recreationally active men (age, 21·7 ± 2·3 year; mass, 74·8 ± 6·5 kg; height, 177·6 ± 5·6 cm) completed four incremental tests to volitional exhaustion, of which two were completed on a treadmill (TRE) and two were completed using a cycle ergometer (CYC). The work rate employed for CYC was 1 W·2 s(-1) from an initial loading of 100 W with cadence being maintained at 60 rpm. For TRE, the workload (gradient) increased at a rate of 0·5% · 30 s(-1) while maintaining a constant running speed of 10 kph. Throughout all the trials, VO2 was determined on a breath-by-breath basis using a precalibrated metabolic cart. The criteria adopted for determination of a plateau was a Δ VO2 over the final two consecutive 30-s sampling periods of ≤50 ml · min(-1). Averaging across the two trials per each exercise modality showed a significant difference for plateau incidence between CYC (8%) and TRE (58%) (P = 0·017). This was aligned with a significant difference in the slope of the regression line during the final 60 s of the VO2max test, CYC (99·9 ± 49·7 ml · min(-1)) and TRE (49·6 ± 42·6 ml · min(-1)) (P = 0·017). Repeat measures ANOVA of these data suggests that plateau incidence rates at VO2max differ between treadmill- and cycle ergometry-based exercises. Future studies need to address whether these response rates are replicated in well-trained athletes.

124 筋張力の発揮能および動作変換率からみた定速走における支持脚筋群の動的特性(筋活動)

124 筋張力の発揮能および動作変換率からみた定速走における支持脚筋群の動的特性(筋活動)

Research of Simulation on the Effect of Suspension Damping on Vehicle Ride

The mathematical model of four degrees of freedom vehicle suspension was established, based on that, built the vibration differential equation and road excitation matrix; the frequency response function and root mean square value which could evaluate response variable were derived; in the case of constant pavement condition and running speed, the simulation in time domain was carried out, the effect tendency of variation of suspension damping to three evaluating indexes of suspension control was obtained, it provided basis for both suspension damping matching with shock absorber damping and research on vehicle ride.

A modeling method of sport shoes for dynamic analysis of shoe-body coupled system

The purpose of this study was to quantify the functional role of compressive characteristics of shoe sole by combining a finite-truss-element shoe sole model and the equation of whole-body motion. The equation of the shoe sole deformation was developed by modeling shoe sole as a construction of truss elements that have nonlinear spring and damper. The properties of the spring and damper were identified from impact test by using an impact device containing an accelerometer and an arm with impactor. The equation of whole-body motion was derived by modeling the human body as a system of 15-rigid linked segments. Dynamic contributions of the support leg joint torques, which were caused by the elastic and viscous forces on the shoe sole, to the generation of whole-body CG's acceleration were calculated under constant running speed condition. A fore/mid foot contact type runner participated as subject. The results in this study indicate that 1) the ankle joint torque caused by the elastic property of the forepart of shoes sole contributes to the acceleration of whole-body CG, and 2) the knee joint torque caused by the viscous property of shoe sole shows negative contribution to the body support but shows positive contribution to the propulsion.