Entrance Speed Research Articles

Modeling of speed in vehicles entering two-way suburban tunnels by Adaptive Neuro Fuzzy Inference System

The behavior of drivers on the roads is elicited from the state of the surrounding environment. The author's research shows that the vehicle starts to decelerate at a certain distance from the tunnel when it is observed, and they have the lowest speed when reaching the beginning of the tunnel. As soon as the tunnel is passed, the vehicle increases speed again in a certain length. The main purpose of this study is to model the speed of vehicles entering suburban tunnels based on the speed changes before entering the tunnel using the neuro-fuzzy network. Then, to validate the designed model, the data of 30 different drivers were used who travel in the same conditions by a Renault Logan vehicle with a manual transmission system. Using the Pearson correlation analysis method, the relationship between the variables of the speed of entrance to tunnel and changes in vehicle speed was investigated. The value of the correlation coefficient is equal to -0.7, which means the strong negative correlation between the two variables. The results show that the neuro-fuzzy network method has the ability to predict speed changes with a high accuracy based on the initial speed of entrance to the tunnel. The results of this study are used to analyze the behavior of drivers in suburban tunnels. Due to the importance of abrupt speed changes in an unusual way, especially on two-way routes, the safety of tunnels can be increased by reducing the stressors in drivers.

Preventing injuries in alpine skiing giant slalom by shortening the vertical distance between the gates rather than increasing the horizontal gate offset to control speed

Background/AimTo set a safe giant slalom course, speed needs to be controlled in certain sections. Speed may be reduced by adjusting how the gates are set on a course. We...

Simulation of the water controlling ability of an adaptive inflow control device

Traditional adaptive inflow control device (AICD) has low water control efficiency. Based on adaptive inflow control device, numerical simulation method is used to analyze the internal flow of the device. Influence of relevant design parameters on its water control capacity is studied. Internal structure of AICD is optimized to change internal flow and the flow path of oil flow in the restrictor. Purpose of controlling the flow of oil by using different viscosities of two flow states is achieved. Results show that setting the baffle to distinguish the annular passage and control chamber can improve pressure drop of water flow. The direction and number of flow channels have significant influence on AICD water control ability. Optimizing the shape of flow channel can change entrance speed and entrance angle, improving the water control capacity of inflow controlling device. The AICD achieves the optimal control capacity when it adopts the one transitional flow channel with 45°A angle.

Simulation research of SCR optimal operation

Selective catalytic reduction technology(SCR) has high denitration efficiency. It is the main techniques adopted in our country of flue gas denitrification. Due to lack of effective NH3 spraying methods and means, stock of low efficiency, high rate of ammonia escape problems, secondary pollution is serious in the actual operation of the existing SCR system. In this paper, using computational fluid dynamics (CFD) method, establishing of three dimensional numerical model of SCR system. Flue gas flow and the NH3/NOx distribution characteristics were analyzed by numerical simulation in SCR system. Studying on the effect of different parameters on the ammonia injection of the reactor entrance speed of the first layer of the catalyst entrance section and the distribution of the NH3/NOx molar ratio, then providing optimizational parameters of the ammonia injection.

The role of path length- and speed-related factors for the enhancement of section performance in alpine giant slalom

Knowing how to enhance alpine skiing performance is essential for effective coaching. The purpose of this study was to explore the role of path length- and speed-related factors for performance enhancement, while skiing on a homogeneously set/constantly inclined giant slalom course section (average gate distance: 27 m; offset: 8 m; slope inclination: 26°). During a video-based three-dimensional kinematic field-experiment, the data of six athletes who skied a two-gate section on four different types of skis were collected. The performance parameter analysed was section time. The performance predictors analysed were centre of mass (CoM), path length and the change in specific mechanical energy per entrance speed along the analysed section. Furthermore, since the current study examined alpine skiing performance within short sections, the skier’s entrance speed was also considered. Classified as a high-performance and a low-performance group based on section time, slow and fast trials significantly differed in CoM path length, the change in specific mechanical energy per entrance speed and entrance speed. The entrance speed of all trials analysed ranged between 15.25 and 17.66 m/s. In trials with both high and low entrance speed, the change in specific mechanical energy per entrance speed was found to be more relevant for the prediction of section time than CoM path length. However, further studies should investigate whether such a prioritization can be unrestrictedly generalized to other situations, such as entrance speeds, course sets, slope inclinations and competition disciplines different to those assessed in the current study.

Software and hardware complex for research and management of the separation process

The article is devoted to the development of a program for studying the operation of an asynchronous electric drive using vector-algorithmic switching of windings, as well as the development of a hardware-software complex for controlling parameters and controlling the speed of rotation of an asynchronous electric drive for investigating the operation of a cyclone. To study the operation of an asynchronous electric drive, a method was used in which the average value of flux linkage is found and a method for vector-algorithmic calculation of the power and electromagnetic moment of an asynchronous electric drive feeding from a single-phase network is developed, with vector-algorithmic commutation, and software for calculating parameters. The software part of the complex allows to regulate the speed of rotation of the motor by vector-algorithmic switching of transistors or, using pulse-width modulation (PWM), set any engine speed. Also sensors are connected to the hardware-software complex at the inlet and outlet of the cyclone. The developed cyclone with an inserted complex allows to receive high efficiency of product separation at various entrance speeds. At an inlet air speed of 18 m / s, the cyclone’s maximum efficiency is achieved. For this, it is necessary to provide the rotational speed of an asynchronous electric drive with a frequency of 45 Hz.

English

Multimedia e-script is a new kind of information media which can be found at present more and more on the shop counter and in the libraries. It is new type of book, which contrary to the classic text-book provides wide advantages at the speed of entrance to information, or implementation of interpretation by animation. People begin to use these forms of education more frequently, because of easy availability (computer with loudspeaker), fast orientation in script, and possibility of repetition of given part of text. This script does not replace the conventional text-books or teacher. Big advantages of such medium are simplicity and easy access to information. Multimedia forms of education cover nearly all fields of study, also technical subjects. Within the learning of technical subjects two features of education should be taken into account – exact and experimental characters. Experiment represents important form of object teaching. The influence of experiments is quite wide; the knowledge obtained during experiments lasts longer time, it has non-formal character and, finally, students can make own conclusions from their own point of view according to their knowledge. These forms of e-learning bring many positive properties for students like contents and quality of education process. By these forms of practices students can verify their theoretical knowledge and they can apply it in praxis.

Estimación de longitud crítica en pendientes ascendentes en caminos bidireccionales

The critical length of grade on two-lane rural roads is used as criterion to assess the need of ascending lanes for heavy vehicles. To estimate it, a speed profile is needed, which depends on the road’s grade and length, and on the physical, dynamic and mechanical characteristics of heavy vehicles. The Chilean standard uses a speed profile for a design truck that have a weight-to-power ratio of 120 kg/kW and an entrance speed of 88 km/h. This unique model prevents from studying cases in which the entrance speed can be different or in which the design vehicle is significantly different to the design speed of standards due to local conditions and consequently, does not allow estimating realistic critical lengths of grades. In this work, speed profiles models based on acceleration and force equilibrium were simulated, considering weight-to-power ratios between 120 and 263 kg/kW, entrance speeds between 80 and 100 km/h. Several values of critical lengths of grades were estimated, which offers engineers more options when designing ascending slopes. Rev. ing. constr. [online]. 2015, vol.30, n.1, pp. 5-16. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732015000100001

Validation of Probabilistic Model for Design of Freeway Entrance Speed Change Lanes

Traffic operation on entrance speed change lanes (SCLs) is more complicated than on exit SCLs as vehicles interact constantly while merging from the SCL to the freeway. An adequate SCL length gives road users sufficient time to accelerate and to search for a gap so that they can comfortably merge onto the freeway. This study focused on analyzing entrance SCLs from a safety point of view in a probabilistic framework. Sixteen entrance-limited-type SCLs along Highway 417 were considered to investigate the link between the probabilistic measure, probability of noncompliance ( Pnc), and collision frequency. Regression analysis was conducted to quantify the effect of the geometry of the SCL, driver merging behavior along the SCL, road users’ exposure, and Pnc on collision occurrence. The model containing Pnc outperformed other models, and the inclusion of Pnc in the regression models resulted in significant improvement in the model fit. The study provided positive evidence on the validity of Pnc as a surrogate measure of safety.

Simulation Research of Flow and Speed on Urban Expressway Interchange Entrance

The urban expressway overpass entrance is an important node of the urban road system. Traffic jams often happen at entrance. The characteristics of urban expressway entrance and the advantages of the microscopic traffic simulation were combined to analyze capacity of entrance. VISSIM simulation software was used and the validity of the simulation model was verified. The influence of the main road traffic flow and the desired speed of entrance to flow and speed of the urban expressway entrance were analyzed through simulation experiment. On the whole, traffic capacity of urban expressway entrance reduces with the increase of traffic flow on the main road. The higher the desired speed is, the faster traffic capacity reduces. The increase of speed and control of main road traffic flow is of great significance for improving the capacity and service level of expressway.

Dynamic Response of an Elastic-Supported Bridge Beam Subjected to Velocity-Varied Moving Loads

Dynamic response of an elastic-supported bridge under speed-varied moving loads was investigated. A mathematical model of vehicle-bridge coupled oscillation for an elastic-supported bridge was built up by means of 1/4 vehicle model (Mass-Spring-Mass) and Euler-Bernoulli beam theory. And then dynamic equations of vehicle-bridge coupled oscillation in matrix form were established using two former orders general coordinates of an elastic-supported beam and model superposition method. The influences of vehicle-bridge coupled vibration model, elastic-supported stiffness, entrance speeds and acceleration /deceleration of moving loads on the dynamic responses of bridges were studied. Vehicle-bridge coupled vibration model based on 1/4 vehicle model can more accurately describe the dynamic characters of bridges than that based on constant moving force model. Elastic-supported stiffness only has an impact on the fluctuation amplitudes of dynamic responses. The vehicle-induced impact factor is dependent on the entrance speeds, acceleration/deceleration of moving loads and elastic-supported stiffness.

Dynamic Response of Vehicle-Bridge Coupled Oscillation Subjected to Velocity-Varied Moving Loads

A mathematical model of vehicle-bridge coupled oscillations for a simple-supported bridge beam subjected to speed-varied moving loads was established according to TFDVM and model superposition method. This model can consider the pitching and vertical movements of a vehicle. By contrast to a vehicle-bridge oscillation coupled model based on one-freedom-degree Mass-Spring-Mass vehicle model (OFDMSMVD), the mathematical model of vehicle-bridge coupled vibrations based on TFDVM can more accurately reflect the dynamic behaviors of vehicle-bridge coupled vibrations .The maximum middle-span deflections of bridges under speed-varied cases are not linearly proportional to the entrance speeds of moving loads, and they happen at a number of entrance speed points of moving loads. The influence of acceleration and deceleration of moving loads on the dynamic deflections of bridges is dependent on the entrance speeds of moving loads.

Modeling Peripheral Vision for Moving Target Search and Detection

Most target search and detection models focus on foveal vision. In reality, peripheral vision plays a significant role, especially in detecting moving objects. There were 23 subjects who participated in experiments simulating target detection tasks in urban and rural environments while their gaze parameters were tracked. Button responses associated with foveal object and peripheral object (PO) detection and recognition were recorded. In an urban scenario, pedestrians appearing in the periphery holding guns were threats and pedestrians with empty hands were non-threats. In a rural scenario, non-U.S. unmanned aerial vehicles (UAVs) were considered threats and U.S. UAVs non-threats. On average, subjects missed detecting 2.48 POs among 50 POs in the urban scenario and 5.39 POs in the rural scenario. Both saccade reaction time and button reaction time can be predicted by peripheral angle and entrance speed of POs. Fast moving objects were detected faster than slower objects and POs appearing at wider angles took longer to detect than those closer to the gaze center. A second-order mixed-effect model was applied to provide each subject's prediction model for peripheral target detection performance as a function of eccentricity angle and speed. About half the subjects used active search patterns while the other half used passive search patterns. An interactive 3-D visualization tool was developed to provide a representation of macro-scale head and gaze movement in the search and target detection task. An experimentally validated stochastic model of peripheral vision in realistic target detection scenarios was developed.

Wind Speed Profiles of an Actual Downburst Based on CFD Numerical Simulation

Downbursts have led to large number of transmission tower failures in the world, so more and more wind engineers are very interested in such strong wind load. Currently the main numerical simulation method of downburst wind load for structural analysis is based on the horizontal divergent wind speed profile of downburst. There have been several available types of empirical wind speed profiles in which some parameters still need to be artificially determined. So, this is a semi-empirical-analytical method which can not be linked with actual downbursts. Some academics have also used CFD numerical method to simulate downburst wind speed profile of high precision grid. But the initial conditions of these CFD simulations were all assumed ideally. In this paper, the wind speed profiles of an actual downburst are simulated by CFD method based on the initial speed of downdraft entrance provided by cloud model. The simulated wind speed profile decays more slowly than an empirical wind speed profile. This conclusion could be of significance for structural engineers to consider downburst wind load reasonably in the structural wind resistant design.

Outsourcing in Healthcare through Process Modularization – A Lean Perspective

Looking for efficiency, quality and profitability gains, healthcare organizations are adopting outsourcing solutions in the attempt of “doing more with less”. Seeking for cost reduction, risk mitigation, adapting to quick changes without compromising internal resources, these organizations also take big risks in control and flexibility variables. In order to understand how healthcare organizations find the best value equation combining internal and external resources in a modular service conception, a case study on a start-up Long-term Care unit with innovative format, great levels of customization and following an outsourcing strategy, was carried out.The main conclusion, among others, is that in ambitious start-ups, having speed of entrance as the conditioning factor, a process orientation and management approach may offer a clear view of the gains related with trade-off decisions regarding time and cost (agility) and cost and quality (Leanness) ie, decisions under the “leagile” paradigm.This study contributes for a wider understanding of the “leagile” concept associated to an outsourcing operational strategy. Additionally, it also provides new insights to the concept of modularity in services settings in a complex service as healthcare.

The Influence of Structural Changes on The Interior Flow Field's Characteristics of Disc Separator

Numerical method was an important means of studying disc separator's interior flow field for optimizing their design. While it reduced the required testing time and costs. Based on the VOF model, the discrete phase model, N-S equations and standard k-ɛ model, the disc separator's interior flow field was simulated. The simulation results showed that: the larger the radius of the center hole the better separation, but the waste of some oil flowed away by water; the entrance location had no effect on the oil-water separation, so the seeper problem at the entrance can be solved by changing the direction of the entrance speed.

Experimental Radar Studies of Anisotropic Diffusion of High Altitude Meteor Trails

At altitudes above 93 km in the atmosphere, magnetic and electric fields can affect the modes and rates of non-turbulent diffusion of ionized meteor trails. Anisotropic diffusion is expected. Most theories of anisotropic diffusion, and indeed most experimental studies, have concentrated on the effects of the magnetic field in producing this anisotropy, and different rates of expansion are expected in directions parallel to and perpendicular to the magnetic field lines. In this study, we use interferometric meteor radars to investigate the dependence of the ambipolar diffusion coefficient on viewing direction relative to the magnetic field, and show that the dependence is at best weak when daily averages are used. We then demonstrate that the reason for this effect is that the positions of maximum and minimum diffusion rates varies as a function of time of day, and that daily averaging masks the anisotropy. One possibility to account for the observations is that this strong diurnal variation is a consequence of the electric fields in the upper atmosphere, which are often tidally driven. An alternative possibility is a diurnal cycle in mean meteor entrance speeds. We lean towards the first hypothesis, but both possibilities are discussed. We demonstrate our results with data from several sites, but particularly using the Clovar radar near London, Ontario, Canada.

Evaluation of choroidal perfusion of the new central macular area by dilution analysis of indocyanine green angiography after macular translocation.

To evaluate the possible long-term alterations of choroidal perfusion parameters in the new central macular area after macular translocation surgery. Eleven subjects with subfoveal neovascular membrane secondary to age-related macular degeneration or degenerative myopia underwent indocyanine green angiography by using a scanning laser ophthalmoscope before and after macular translocation (mean, 10 months after surgery). Fluorescence intensity of the new central macular area over time was evaluated. Parameters derived from the intensity curves included 10% filling time, ascending slope, and maximal intensity of brightness. The 10% filling time reflects the rapidity of the early choroidal filling phase, whereas the slope of the filling of the curve shows the speed of blood entrance into the choroid. Maximal intensity of brightness indicates vascular density of the area. No statistical difference was encountered before or after macular translocation in 10% filling time (14.25 +/- 2.09 seconds versus 16.20 +/- 2.95 seconds), slope of the ascending portion of the curve (0.12 +/- 0.04 versus 0.11 +/- 0.04), and maximal intensity of brightness (0.89 +/- 0.09 versus 0.88 +/- 0.07) in the new central macular area. The rotational degree of the retina against the retinal pigment epithelium did not show any significant correlation with 10% filling time, slope, or maximal intensity of brightness. Choroidal perfusion parameters in the new foveal region do not change after macular translocation surgery.

Real-time determination of meteor-related parameters utilizing modern digital technology

Modern fast digitization techniques and computer methods have been combined with both new and old theoretical approaches to permit construction of a new class of meteor radar. This radar can simultaneously stream data into memory, detect occurrences of meteors, and determine the location of meteor trails (range and angle), as well as find their radial drift speeds and decay times. The meteor entrance speeds as the meteors enter the atmosphere can also be determined. These parameters may then be used to deduce meteor fluxes, as well as winds, temperatures and diffusion coefficients at altitudes of 80–100 km. This information can also be used to deduce source positions of meteor shower radiants. Some of these capabilities are very new, especially the ability to measure atmospheric temperatures at ∼90 km altitude.

Real‐time meteor entrance speed determinations made with interferometric meteor radars

Previously developed methods for determination of meteor entrance speeds into the Earth's atmosphere are extended and unified and applied to a real‐time radar system. A Fourier transform approach, using a rescaled time axis, is employed, permitting entrance speed determinations with accuracies of the order of 0.5 km s−1. After the method is described, it is demonstrated by using it to determine the entrance speeds of several major streams, including the Zeta Perseids, the Arietids, the Beta Taurids, the June Bootids, meteors from within the Piscids complex, and the Geminids. Values are consistent with previous optical measurements, but in some cases the radar measurements have higher accuracy. The possibility of detection of space debris, or perhaps dust in Earth orbit, is also considered.