Entrance Location Research Articles

Flow structure and surface heat transfer from numerical predictions for a double wall effusion plate with impingement jet array cooling

To provide additional understanding of double wall cooling arrangements, especially local distributions of flow properties which are responsible for hot-side surface and cold-side surface heat transfer variations, investigated are numerically-simulated distributions of turbulent flow structural characteristics. Also considered are numerically-simulated surface heat transfer characteristics, including comparisons with experimentally-measured distributions. The numerical results are obtained using the ANSYS FLUENT Version 19.1 numerical code, with a k-ω SST turbulence model. The present arrangement includes a full-coverage effusion cooling plate, with coolant initially supplied by an impingement jet array. Considered are the effects of effusion blowing ratio, impingement jet Reynolds number, and streamwise development on flow structure, and on hot-side and cold-side surface heat transfer characteristics. Data are obtained for an approximately constant main flow Reynolds number of 138000 to 159000, with blowing ratios from 2.2 to 8.5, which correspond to impingement jet Reynolds numbers from 7360 to 25200. Of particular importance are horseshoe-shaped vortices, which form upstream and around each effusion jet, which then result in two horseshoe-originated vortex legs which advect downstream along coolant trajectories. Also important are secondary flows, local flow separation regions, and local velocity regions, which are evident within the effusion hole passages near entrance locations. Within the cross flow passage, locally increased flow velocities, associated with impingement jet locations, are apparent, especially near the lower surface of the cross flow passage. These are associated with regions of augmented streamwise vorticity, which are present around the circumference of each impingement jet.

The relative importance of wind-driven and chimney effect cave ventilation: Observations in Postojna Cave (Slovenia)

Density-driven chimney effect airflow is the most common form of cave ventilation, allowing gas exchange between the outside and the karst subsurface. However, cave ventilation can also be driven by other mechanisms, such as barometric changes or pressure differences induced by the outside winds. We discuss the mechanism and dynamics of wind-driven ventilation using observations in Postojna Cave, Slovenia. We show how seasonal airflow patterns driven by the chimney effect are substantially modified by outside winds. Wind flow over irregular topography forms near-surface air pressure variations and thus pressure differences between cave entrances at different locations. These pressure differences depend on wind speed and direction and their relationship to surface topography and the location of cave entrances. Winds can act in the same or opposite direction as the chimney effect and can either enhance, diminish or even reverse the direction of the density-driven airflows. To examine the possibility of wind-driven flow, we used a computational fluid dynamics model to calculate the wind pressure field over Postojna Cave and the pressure differences between selected points for different configurations of wind speed and direction. We compared these values with those obtained from airflow measurements in the cave and from simple theoretical considerations. Despite the simplicity of the approach and the complexity of the cave system, the comparisons showed satisfactory agreement. This allowed a more general assessment of the relative importance of wind pressure for subsurface ventilation. We are certain that this example is not unique and that the wind-driven effect needs to be considered elsewhere to provide better insights into the dynamics of cave climate, air composition or dripwater geochemistry.

Evaluation of the Course of Inferior Alveolar Canal and its Relation to Anatomical Factors on Digital Panoramic Radiographs.

Statement of the Problem: The inferior alveolar canal (IAC) is a bony canal that starts from mandibular foramen at the inner surface of the mandibular ramus and extends along the ramus and body of mandibular bone in forward and downward directions to the mental foramen. Inside the mandibular canal, there are lower alveolar artery and a nerve with the same name. Understanding the anatomical details of the lower alveolar canal, including position, pathway and morphology to prevent complications in surgical procedures in the lower jaw such as mandibular impacted molar surgeries, mandibular nerve block injection, or even root canal treatment of mandibular teeth is important. Purpose: The purpose of this study was to investigate the course and direction of IAC in mandibular bone and its relation to anatomical factors such as gonial angle and location of entrance of IAC in the mandibular ramus.Materials and Method: This cross-sectional study evaluated a sample of 280 digital panoramic images. All samples were Iranian. The pattern and direction of the IACs were recorded according to age and gender and the relation of these patterns to the gonial angle of mandible and the entry point of the IAC in mandibular ramus were evaluated.Results: The results showed that the course of canal, the entrance point of the canal and the gonial angle were the same between different age groups and between two genders. There was no significant relation between the course of canal and the two anatomical variables mentioned (p> 0.05).Conclusion: Considering the increasing frequency of implant surgeries and presence of different courses of the mandibular canal and concerning the important complications such as paresthesia caused by damage to the mandibular nerve, panoramic radiography is necessary before any surgery in this area to avoid unwanted injuries to the neurovascular system if other advanced modalities are not available.

Determination of Ghost Fishing Starting Time by Four Different Baited Fish Traps in the Çanakkale Strait (North Aegean Sea)

In this study, the starting time of ghost fishing in baited fish traps were determined. Two separate trials using 4 different types of fish traps (foldable, conical, “O” shaped Round and cylindrical) were carried out in the Çanakkale Strait at a depth of 5m between July - December 2013. A total of 12 fish traps (3 for each trap type) were used in the study. Each trial lasted a period of 45 days. Major features of the traps were as follows: the foldable fish trap had “V” shaped inclined funnel; the conical fish trap had a conical entrance from the top; The “O” shaped fish trap had a “V” shaped entrance on the base; the cylindrical trap had a conical entrance on the side. In all trials fresh sardine, black mussel and bread placed in a net bag were used as bait and fixed in the traps. Underwater observations showed that fish entrapped in all trap types escaped from the traps within 8-10 days. Fish mortality was due to accidental entanglement of fish on the mesh material covering the traps or due to predation. Molluscs such as octopuses and squids escaped within 4-7 days whereas crabs suffered from cannibalism or starvation due to their lower escape rates. In conclusion, in the present study while trap ghost fishing for fish and cephalopods were not observed, ghost fishing for crabs were observed and was a factor of entrance design and location on traps.

Entrance Location Planning of HOV Lanes in Multi-lane Highway Considering System and HOV Lane State

The high-occupancy vehicle (HOV) lane is an effective traffic demand management that encourages carpooling. In this study, we examine entrance location planning of HOV lanes. A highway commuting system containing HOV lanes is proposed. Commuters make travel choices based on the principle of minimum commuting time, i.e., the system is in the user equilibrium state. By planning the HOV lanes’ entrance location, the manager indirectly influences the commuters’ travel choices, thus achieving the predetermined management goals. In this study, an optimization model is developed where the decision variable is the entrance location of the HOV lane, and the conditional constraint of user equilibrium is satisfied. The objective function is a weighted average of a system state indicator and an HOV lane state one. Numerical examples show that the proposed method solves the location planning problem of the HOV lane entrance. The quantitative results reveal that the system congestion is relieved when the HOV lane entrance is close to the city center, and the traffic condition of the HOV lane is improved when the entrance is close to the city’s edge.

Using arthroscopy combined with fluoroscopic technique for accurate location of the bone tunnel entrance in chronic ankle instability treatment

BackgroundMinimally invasive reconstruction techniques are used for anatomical ligament construction of the lateral collateral ligament complex of the ankle, but the two key elements, the bone tunnel and the appropriate graft tension, for the identification of the anatomic location during the surgery are not clearly stated.MethodsThe patients with chronic ankle instability who received arthroscopic anatomic lateral ligament complex reconstruction were retrospectively analyzed. The anatomical location of the bone tunnel was performed under arthroscopy combined with fluoroscopy for accurate location of the bone tunnel entrance. The graft tension and routing were controlled under arthroscopic visualization. The clinical outcomes were assessed using the Karlsson-Peterson score, Sefton articular stability scale, and Visual Analogue Scale (VAS). The complications were recorded during the follow-up.ResultsA total of 18 patients were enrolled in this study. The mean follow-up was 33.33 ± 3.69 (range from 24 to 36) months. No patient had recurrence of ankle instability after the operation. According to the Sefton articular stability scale, 94.5% of the patients had excellent/good function. The mean value of the anterior drawer tests and the talar tilt angle examination were decreased. The mean of the Karlsson-Peterson score and the Visual Analogue Scale(VAS) score were both improved significantly.ConclusionsThe anatomic reconstruction of the ankle lateral ligament complex to treat chronic ankle instability using the arthroscopy combined with the fluoroscopic technique could improve the clinical functions, satisfaction, and reduced pain of patients.

Identifying Three-Dimensional Swimming Corridors for Fish to Match Their Swimming Characteristics Under Different Hydropower Plant Operations: Optimization of Entrance Location for Fish-Passing Facilities

Identifying Three-Dimensional Swimming Corridors for Fish to Match Their Swimming Characteristics Under Different Hydropower Plant Operations: Optimization of Entrance Location for Fish-Passing Facilities

Optical investigations of nozzle geometrical and dynamic factors on formation and development characteristics of string cavitation with large-scale diesel tapered-hole nozzles

Cavitation is known to be an essential physical phenomenon to induce the fuel primary breakup process, which further influences subsequent secondary atomization and combustion in diesel engines. Different from normal geometry-induced cavitation, the special vortex-induced cavitation, which may influence strongly spray characteristics, is seldom investigated comparatively. In this paper, formations and developments of string cavitation are captured in scaled-up transparent replicas of diesel tapered-hole nozzles by high-speed imaging technology. The ensemble average images were post-processed by MATLAB code for characterizing the string cavitation at fixed needle lifts. The results indicate that string cavitation tends to occur initially in the middle of the nozzle holes. Besides, shedding bubbles from geometry-induced cavitation may stimulate the string cavitation inception as an inducing factor. The morphology and duration of both two types of string cavitation are largely influenced by needle lifts and cavitation number. Moreover, it is concluded that string cavitation hardly occurs in nozzles with low hole entrance location, and the hole entrance rounding structure changes the distribution characteristics of string cavitation. Finally, it is ascertained that the variation of magnification ratio changes little or nothing about development and distribution characteristics of string cavitation.

Site formation processes at Manot Cave, Israel: Interplay between strata accumulation in the occupation area and the talus

Manot Cave contains important human fossils and archaeological assemblages related to the origin and dispersal of anatomically modern humans and the Upper Paleolithic period. This record is divided between an elevated in situ occupation area and a connecting talus. We, thus, investigated the interplay between the accumulation of the sediments and their associated artifacts in the occupation areas and the translocation of part of these sediments and artifacts down the talus. We examined the lithostratigraphy of two excavation locations in the occupation area (areas E and I), and two in the talus (areas C and D). We also assessed the diagenetic processes that have affected all these areas. A linear array of stalagmites and stalactites separates the occupation area from the talus, demarcating a major topographic barrier between the two. We infer that during human occupation, sediment accumulation of soil, wood ash, and bone was rapid and that some sediments with their associated artifacts overflowed the barrier and translocated down the talus. During periods of nonoccupation, the ash in the occupation area partially dissolved owing to the release of acid from the degrading bat and bird guano, and the layer thicknesses decreased. The south side of the talus (area C) has a normally stratified archaeological record, with the older archaeological materials underlying the younger materials. This suggests that the barrier between the occupation area and area C was relatively shallow and allowed a fairly continuous sediment accumulation in the talus. In the central part of the talus (area D), the stratigraphy is complex and shows mixing, presumably owing to the steep underlying bedrock topography and the mixing that occurs when sediments move down a steep slope. Finally, the distribution of secondary phosphates is consistent with the location of a main cave entrance to the south of the Paleolithic occupation area.

X-Ray Beam Segment Size and Entrance Location Effects on the Integral Quality Monitor (IQM®) Signal and Usefulness in Predicting Complex Segment Output Signals.

Background: The Integral Quality Monitor (IQM®) is an independent online dosimetry device attached to the treatment machine to monitor the accuracy of radiation delivery.Objective: This study investigates the influence of beam segment size and displacement as projected onto the IQM chamber on the signals and determine how individual signals can be added to get a combined segment signal made up of smaller segments.Material and Methods: This is an experimental original research type of study. IQM response maps were generated by irradiating the IQM sensitive area with small elementary segments and measuring their corresponding signals per monitor unit (MU). The output signal/MU was measured for regular and irregular fields and compared with the predicted signal/MU obtained from decomposing the open segment into a set of smaller regular segments and summing their signals from their respective response maps. The dependence of signals on segment size, shape, location and combination was investigated. Results: Predicted signals were calculated within 95-98 % accuracy for regular fields and 90-98% for irregular fields. More uniform fluence contain distribution for larger segments was observed. Response maps were consistent with the geometrical symmetry in the chamber’s wedge shape and the symmetry in the linac fluence. Conclusion: The field decomposition method allows the pre-calculation of known segment output signals per MU within 2% error, although the accuracy drops significantly for smaller, irregular fields. A method of correcting predicted signals in smaller segments needs to be laid down to get a better match with measured signals.

Slow uniform electrical activation during sinus rhythm is an indicator of reentrant VT isthmus location and orientation in an experimental model of myocardial infarction

BackgroundTo validate the predictability of reentrant circuit isthmus locations without ventricular tachycardia (VT) induction during high-definition mapping, we used computer methods to analyse sinus rhythm activation in experiments where isthmus location was subsequently verified by mapping reentrant VT circuits. MethodIn 21 experiments using a canine postinfarction model, bipolar electrograms were obtained from 196-312 recordings with 4mm spacing in the epicardial border zone during sinus rhythm and during VT. From computerized electrical activation maps of the reentrant circuit, areas of conduction block were determined and the isthmus was localized. A linear regression was computed at three different locations about the reentry isthmus using sinus rhythm electrogram activation data. From the regression analysis, the uniformity, a measure of the constancy at which the wavefront propagates, and the activation gradient, a measure that may approximate wavefront speed, were computed. The purpose was to test the hypothesis that the isthmus locates in a region of slow uniform activation bounded by areas of electrical discontinuity. ResultsBased on the regression parameters, sinus rhythm activation along the isthmus near its exit proceeded uniformly (mean r2= 0.95±0.05) and with a low magnitude gradient (mean 0.37±0.10mm/ms). Perpendicular to the isthmus long-axis across its boundaries, the activation wavefront propagated much less uniformly (mean r2= 0.76±0.24) although of similar gradient (mean 0.38±0.23mm/ms). In the opposite direction from the exit, at the isthmus entrance, there was also less uniformity (mean r2= 0.80±0.22) but a larger magnitude gradient (mean 0.50±0.25mm/ms). A theoretical ablation line drawn perpendicular to the last sinus rhythm activation site along the isthmus long-axis was predicted to prevent VT reinduction. Anatomical conduction block occurred in 7/21 experiments, but comprised only small portions of the isthmus lateral boundaries; thus detection of sinus rhythm conduction block alone was insufficient to entirely define the VT isthmus. ConclusionsUniform activation with a low magnitude gradient during sinus rhythm is present at the VT isthmus exit location but there is less uniformity across the isthmus lateral boundaries and at isthmus entrance locations. These factors may be useful to verify any proposed VT isthmus location, reducing the need for VT induction to ablate the isthmus. Measured computerized values similar to those determined herein could therefore be assistive to sharpen specificity when applying sinus rhythm mapping to localize EP catheter ablation sites.

FLOW-3D software for substantiation the layout of the port water area

It is necessary to exclude the occurrence of significant waves in the inner water area of the port and at the berthing facilities when designing breakwaters. The article presents the results of the calculations of water movement in the harbor area. The most secure options for the location of the port entrance and its size for a given object were identified. The possibility of using the FLOW – 3D program to select planned and constructive solutions at the stage of the preliminary layout of the port water area is substantiated.

How do consumers process digital display ads in-store? The effect of location, content, and goal relevance

This study examines under which circumstances customers are more likely to process in-store digital display ads. An exploratory field study is conducted (n = 296), with a between-subjects, 2 (value-expressive versus utilitarian messages) by 2 (entrance versus register location) by 2 (low versus high goal relevance) quasi-experimental design, in a retail store of horticulture-, baking- and pet supplies. The findings show that DS can appeal to both segments of customers when positioned in proximity to the register, rather than the entrance. In terms of the content displayed, there is no ‘one-size-fits-all’ approach as both types of content have different effects, depending on the shopping goal of the customer.

Behavioral stereotypy and some ecological consequences of entrance-shaft placement of the domichnium Sanctum laurentiensis in Ordovician trepostomate Bryozoa

The ichnofossil Sanctum laurentiensis from the Late Ordovician (Cincinnatian) of Laurentia is a domichnium tunneled into live colonies of ramose and frondose trepostome Bryozoa. A preferred entrance location was chosen by the trace-making endoskeletozoan. The organism chose to tunnel in positions near growing tips of branches where one of two conditions prevailed. At stereotypical sites, here considered “determinate”, domicile entrances were made where a trepostome branch was in the growth process of bifurcation; sites considered “indeterminate” were chosen where one blade or branch was impinging on another, or on some other nearby substrate, thus interfering with normal colony growth in a random, or non-ontogenetic, manner. This stereotypy is a rare example of demonstrable entrance-siting behavior by an unknown invertebrate organism. A skeleto-structural condition was present at both determinate and indeterminate locations on ramose trepostome colonies. Stereotypical entrance-site choices included a location where bryozoan freewall membrane was compromised or thinned and exozone was incompletely developed. Sanctum producers preferred incomplete exozone in order to access the endozone for excavation to form a domichnium. Middle and Late Ordovician diversification of ramose bryozoan forms stimulated escalation of bioeroder and symbiont taxa in living zoaria thus encouraging further trepostome evolution.

Park Accessibility Analysis Based on Location Information and GIS: Take Shanghai Hongkou District As An Example

Spatial accessibility is one of the methods to study the rationality of park design. This paper is taking Hongkou District Park in Shanghai as an example, by using the ARCGis application as analysis tool to analyze that the relation between the location of Park entrance and location of the community, and to calculate the different time cost of people who is under the walking and cycling mode to put forward the distribution of park entrance location which is based on the accessibility of riding and walking.

Ventricular scar channel entrances identified by new wideband cardiac magnetic resonance sequence to guide ventricular tachycardia ablation in patients with cardiac defibrillators.

Ventricular tachycardia (VT) substrate-based ablation has become a standard procedure. Electroanatomical mapping (EAM) detects scar tissue heterogeneity and define conduction channels (CCs) that are the ablation target. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is able to depict CCs and increase ablation success. Most patients undergoing VT ablation have an implantable cardioverter-defibrillator (ICD) that can cause image artefacts in LGE-CMR. Recently wideband (WB) LGE-CMR sequence has demonstrated to decrease these artefacts. The aim of this study is to analyse accuracy ofWB-LGE-CMR in identifying the CC entrances. Thirteen consecutive ICD-patients who underwent VT ablation after WB-LGE-CMR were included. Number and location of CC entrances in three-dimensional EAM and in WB-LGE-CMR reconstruction were compared. Concordance was compared with a historical cohort matched by cardiomyopathy, scar location, and age (26 patients) with LGE-CMR prior to ICD and VT ablation. In WB-CMR group, 101 and 93 CC entrances were identified in EAM and WB-LGE-CMR, respectively. In historical cohort, 179 CC entrances were identified in both EAM and LGE-CMR. The EAM/CMR concordance was 85.1% and 92.2% in the WB and historical group, respectively (P = 0.66). There were no differences in false-positive rate (CC entrances detected in CMR and absent in EAM: 7.5% vs 7.8% in WB vs. conventional CMR, P = 0.92) nor in false-negative rate (CC entrances present in EAM not detected in CMR: 14.9% vs.7.8% in WB vs. conventional CMR, P = 0.23). Epicardial CCs was predictor of poor CMR/EAM concordance (OR 2.15, P = 0.031). Use of WB-LGE-CMR sequence in ICD-patients allows adequate VT substrate characterization to guide VT ablation with similar accuracy than conventional LGE-CMR in patients without an ICD.

A CFD ANALYSIS OF THE INFLUENCE OF PLENUM CONFIGURATIONS ON GAS DISTRIBUTION IN A FLUIDIZED BED

Fluidized beds are widely used in many industries. The fluidization quality of these units is strongly related to the characteristics of the plenum and distributor (grid). In this work, the effect of different plenum geometries, and gas entrance sizes and locations on the velocity profile above the distributor was analyzed by Computational Fluid Dynamics (CFD). The results showed that flow uniformity above the distributor improved with an increase in the gas inlet diameter and the plenum height. Channeling was observed for the bottom central inlet. Additionally, simulations for plenum heights predicted by one of the frequently used correlations (Litz correlation) were also carried out and showed, especially for a bottom central gas inlet, a poor quality flow distribution. This behavior indicated that Litz correlation tends to underestimate the plenum height for obtaining a uniform flow downstream the distributor.

Coordinated Intersection Signal Design for Mixed Traffic Flow of Human-Driven and Connected and Autonomous Vehicles

This manuscript investigated coordinated intersection signal design problem for mixed traffic flow of Human-Driven Vehicles (HDVs) and Connected and Autonomous Vehicles (CAVs). Two main macroscopic impact of the mixed flow on signal setting are considered: saturation flow rate and the platoon dispersion. In order to capture the traffic flow operational characteristics on coordinated intersections, three locations, namely entrance location where the loop detector was located at, and upstream intersection and downstream intersection were defined. Two types of vehicle cumulative curves, namely cumulative arrival profile and cumulative departure profile were constructed. The mixed-flow traffic dynamics were analyzed, and the arrival-departure curves relationship was derived using a combination of Newell car-following and Akcelik acceleration model. A mixed-flow platoon dispersion model was proposed to describe the vehicle’s progression between two locations. Due to the nonlinear nature of the problem, a particle swarm optimization (PSO) method was employed to obtain the optimal signal parameters, including the cycle length, green duration, and optimal offset. The algorithm was implemented and validated in a case study involving two intersections, with the demand formulated and simulated by the Markov chain. The results showed that the proposed model could effectively decrease delays when compared with current signal control methods.

An efficient algorithm based on electrograms characteristics to identify ventricular tachycardia isthmus entrance in post-infarct patients.

Our study assesses the value of electrograms (EGMs) characteristics to identify a ventricular tachycardia (VT) isthmus entrance in patients with post-infarct VT. Post-infarct VTs are mostly due to a re-entrant circuit. A pacemapping (PM) approach is able to localize the VT isthmus during sinus rhythm. Limited data are available about the role of local EGMs in defining VT isthmus location. Twenty consecutive patients (70% male) referred for post-infarct VT catheter ablation were included in the present study. The VT isthmus was defined according to the PM method. At each recording site, 10 characteristics of the local EGM were assessed to predict the location of the VT isthmus entrance. In total, 924 EGMs were acquired, of which 127 were located in the VT isthmus entrance. Logistic regression analysis showed that bipolar voltage, number of EGM positive peaks, and sQRS interval were independently associated with VT isthmus entrance location. The ROC curve best fitted the model at the cut-off 0.1641 (sensitivity 72%, specificity 75.2%, positive predictive value 31.3%, negative predictive value 94.4%, area under the curve 0.78, P < 0.001). Based upon these results, we developed an algorithm implemented in an automatic calculator to determine the likelihood that an EGM is located at a VT isthmus entrance. Our study suggests that three EGM characteristics: bipolar voltage, number of positive peaks, and sQRS interval can successfully identify a VT isthmus entrance in post-infarct patients.

Catchment if you can: The effect of station entrance and exit locations on accessibility

The success of passenger railway systems depends on their ridership and thus the population they serve. A mechanism to increase ridership is to expose the existing system to more people by reconfiguring the station itself, for instance by adding extra entrance and exit gates to shorten the walking distance from a trip's origin or its final destination. Gates are key nodes giving pedestrians access from street network to boarding/alighting facilities and vice versa. Stations and platforms are places not points, passengers may spend up to 6 min a trip walking between platforms and the end of the station nearest their origin or destination. This study systematically evaluates the accessibility of train stations and the effect of constructing an additional ‘far-side’ gate at stations with a single ‘near-side’ entrance. A three-step approach is defined to generate an isochrone as the catchment area for any transport node. Results indicate that stations with a single gate along their platforms (usually on one end of them) have the potential to increase the accessibility to jobs and population by around 10% on average. Due to the walking network and land use characteristics, some stations will benefit more significantly by retrofitting a new gate. Also, four linear regression models are developed to illustrate the effect of expanded accessibility on the number of entries and exits at each station for two peak periods. Then, stations are ranked based on their added ridership, which can help authorities to prioritize the development and allocating resources.