Multiple Orifices Research Articles

A caudate branch as the anatomical landmark for optimal bile duct division during donor hepatectomy

Introduction: Optimal bile duct division line should prevent multiple orifices on the graft and biliary stricture of donors. Magnetic resonance cholagiopancreatography (MRCP) is used most commonly to assess donor bile ducts preoperatively. We have identified caudate branches arising from hilar bifurcation in MRCP. This study evaluated the feasibility of caudate branches shown in MRCP as anatomic landmark during bile duct division by confirming the location using probing method or operative cholangiogram. Method: From February 2016 to December 2017, 57 patients undergoing donor right hepatectomy were evaluated. Prospective data collection for location of caudate branches on MRCP and identification of corresponding caudate branches during operation was performed. Results of probing method or operative cholangiogram were also collected to confirm the anatomic landmark. Clinical characteristics and postoperative outcomes were evaluated. Result: Clinical characteristics showed that median age was 35 years old (range: 17-57). Preoperative evaluation of MRCP showed that 26 patients (87%) were possible candidates for single bile duct opening in the graft. Median distance from hilar bifurcation to right 2nd order division on MRCP was 8.5 mm (range: 3-16 mm). Operative outcomes showed that 20 patients (67%) showed single graft bile duct, 9 patients (30%) showed two graft bile ducts and 1 patient (3%) showed three graft bile ducts. Caudate branches were identified in 29 patients (97%). Probing method was found to be difficult in 10 patients (33%) and operative cholangiogram was performed to confirm the location of the bile duct division line in correlation with the caudate branches. Postoperative outcome showed that median length of hospital stay was 9 days (range: 7-15 days) and there were three cases (10%) of grade I Clavien-Dindo complications. Conclusion: A caudate branch may be used as the anatomical landmark for optimal bile duct division during donor right hepatectomy.

Heat transfer enhancement of a heated cylinder with synthetic jet impingement from multiple orifices

This study proposed and investigated a method to enhance the heat transfer performance of a heated cylinder with synthetic jet impingement from multiple orifices. A synthetic jet has a flow with alternately changing orientations at its exit and eventually generates a periodic flow in constant orientation in the area far from the exit. First, the flow characteristics of synthetic jets generated from the multiple orifices on a piccolo tube were investigated in detail with a hot-wire anemometer. Next, the heat transfer of a heated cylinder was enhanced with multiple synthetic jets. The Nusselt number of the heated cylinder was calculated using the temperature variation of the cylinder with time. The heat transfer rate enhanced with multiple synthetic jets was 2–3 times higher than that without jets. The results also showed that the heat transfer rate with upward-oriented jets from the piccolo tube located below the heated cylinder was higher than that with downward-oriented jets from the tube located above the cylinder. We also compared synthetic jets to continuous jets generated with a high-pressure air source. The results showed that the effects of the synthetic jets were valid at greater distances than those of the continuous jets.

Dynamic Characterisation of Rectangular Aerostatic Pads with Multiple Inherent Orifices

Aerostatic pads are successfully employed in linear systems where very accurate and precise positioning is required, e.g. machine tools and measuring equipment. Both the static and dynamic performance of many different types of aerostatic pads have been already numerically and experimentally investigated. However, literature does not present so many works that investigate the performance of rectangular aerostatic pads with multiple restrictors, especially as regards their dynamic features. This paper shows an experimental and a numerical study of the static and dynamic performance of a rectangular aerostatic pad with multiple orifices distributed on a supply rectangle. The paper investigates the effect of the orifices diameter, of their position and of the supply pressure on the pad performance.

Modelling of Surface Permeation in Multiple-Orifice Permeable Road

A patent-pending StormPav green pavement is introduced here as a form of permeable road, in which the system employed precast concrete pieces as modular units. The pavement layer consists of hexagonal plates with each a service inlet to drain water. This study is exploring the water draining capability or technically surface permeation of these service inlets. Virtual and physical modelling are performed to investigate the service inlets as multiple orifices to permeate surface water of the said permeable road. Both modelling efforts have deduced that the permeable road has 18,000 – 24,000 mm/hr of permeation rate when subjected to a 5-minute red-alert storm (>60mm/hr of intensity). It implies that StormPav green pavement has superior surface permeation against the forming of water ponding and flash flood on roads.

Investigation on interphase mixing and flow condensation process in a vertical channel

In this paper, an experimental study is performed on the mixing of superheated gas and subcooled flowing liquid and the subsequent flow condensation process in a vertical visual flow channel using R123 as the working fluid. The flow patterns of the two phase flow in the vertical channel are verified and the flow condensation lengths of the gaseous phase under different operating conditions are obtained. Test results indicate that under the operating conditions in this experiment, the gaseous phase forms a cavity or a film at the gas orifices, and then forms a dispersive bubbly flow in the downstream region. The flow condensation length of the gaseous phase through a single orifice increases approximately linearly with the gas flow rate over a range of 0.35–0.76 m, and it is reduced to a range of 0.27–0.56 m by using multiple gas injection orifices. A computational fluid dynamics (CFD) model is established to simulate the two phase flow and interfacial heat and mass transfer in the channel. The simulation capability and prediction accuracy of the CFD model are validated by comparing numerical results of phase distributions as well as the flow condensation lengths with test data, and satisfying agreements are obtained. This work could be beneficial to the understanding and handling of interphase heat and mass transfer problems in in-tube two phase flows.

Combustion performance of nozzles with multiple gas orifices in large ladles for temperature uniformity

In order to improve the baking temperature uniformity of the large ladle in steelmaking plants, the flame combustion characteristics of nozzles with different inner structures were numerically simulated with the finite volume method code Fluent. The flow field and premixed combustion reaction inside and outside the nozzle with multiple gas orifices were exhibited. Meanwhile, the influences of the gas injecting angle and the number of gas orifices on temperature, velocity, and pressure fields were studied. The results show that the flame length and width at the rear of flame temperature field reach the maximum values in the nozzle with the gas injecting angle of 20° and 4 gas orifices for the control of premixed combustion inside the nozzle, which could provide better temperature uniformity in ladles. The length of the 1273 K isothermal surface is 4.89 m, and the cross-section area at 4 m away from the outlet of the nozzle is 0.13 m2. The pressure losses of different types of nozzles range from 112.2 to 169.4 Pa and decrease with the decrement in gas injecting angle and the number of gas orifices. The ladle bottom preheating temperature is increased by 320–360 K for the optimized nozzle. The inner surface temperature differences between wall and bottom of the ladle are less than 10%. There is good baking temperature uniformity after the application of optimum structurally designed nozzles.

Drainage from a Fluid-Handling Component with Multiple Orifices due to Inclination or Rotation.

The onset of drainage of liquids from fluid-handling components with two or more orifices was evaluated. The components were filled with water, ethylene glycol, or ethyl alcohol and oriented vertically with their orifices facing downward. The lower end of the components was slowly raised toward the horizon. No flow occurred until a critical angle of inclination was reached. The resistance to drainage was greatest for small, closely spaced orifices and declined precipitously as the size and spacing of the orifices increased. The onset of drainage was successfully modeled as a balance between the hydrostatic pressure in the bulk liquid and the Laplace pressure of the air-liquid interfaces present within the orifices.

In Situ Procurement of a Recipient's Portal Vein for a Right Lobe Liver Graft With Multiple Venous Orifices: A Case Report

Reconstruction of multiple venous orifices of a right lobe graft is a time-consuming and troublesome procedure in right lobe living-donor liver transplantation. In the current study, we present a new venous reconstruction technique for a right lobe graft with multiple and complex hepatic vein (HV) orifices, in which procurement of the recipient's left portal vein was performed in situ to keep the anhepatic period to a minimum. All of the HV orifices were reconstructed together at the back table, while maintaining patency of the recipient's systemic and splanchnic circulation. A homologous vein graft and veno-venous bypass were not necessary. All HVs were patent during the follow-up and the patient was free from complications. In conclusion, the present technique is readily available for reconstruction of complex and multiple HV tributaries, while avoiding a long anhepatic time and the use of veno-venous bypass.

Experimental study on heat transfer characteristics of a heat sink with multiple-orifice synthetic jet

Application of a synthetic jet is reasonably a novel approach for cooling of electronic components. The heat transfer enhancement using impinging multiple-orifice synthetic jet is investigated experimentally. A heat sink is mounted on the heat source and the resulting heat transfer characteristics are presented. The experiments are conducted for different configurations of multiple circular orifices. The input parameters such as excitation frequency, pitch circle radius (PCR) and axial distance from tip of the heat sink fin to orifice plate are considered in the study. The performance of the heat sink in terms of spatial-average heat transfer coefficient (havg) and thermal resistance is documented. While impinging on the heat sink, the maximum heat transfer coefficient obtained with multiple-orifice synthetic jet is 12% higher than a conventional single orifice synthetic jet and six times greater than the corresponding case with the bare heated surface. The PCR of the satellite orifices have a negligible effect on thermal resistance of the heat sink. The center orifice of the multiple-orifice arrangement plays a vital role in reducing thermal resistance of the heat sink. A synthetic jet-heat sink combination exhibits an identical thermal performance with that obtained with a conventional fan-heat sink mechanism. Thermal resistance of the heat sink shows decay with increase in input power to synthetic jet actuator. However, such behavior is not demonstrated by a fan. The minimum thermal resistance of the heat sink with multiple-orifice synthetic jet is found to be up to 10 times higher than the thermal resistance for natural convection. Empirical relations are developed from experimental data describing the variation in thermal resistance as a function of input power. Efficiency of synthetic jet with multiple-orifice arrangement is found to be marginally lower as compared to a standard commercial fan. However, multiple-orifice synthetic jet can emerge as an inexpensive cooling method in comparison with a fan. The results presented in this paper suggest that the synthetic jet is capable of replacing the fan in fan-heat sink mechanism employed for cooling of electronic devices.

Turbulent Characteristics and Design of Transverse Jet Mixers with Multiple Orifices

We investigated and compared the turbulent characteristics of two-liquid mixing in single-orifice and multiorifice-impinging transverse (MOIT) jet mixers through large eddy simulations and the planar laser-induced fluorescence technique. Our focus is on evaluating the roles played by the interactions among the jets in the mixing intensification. The turbulent vortex structures, time-averaged mean concentration distributions, root-mean-square of the concentration fluctuations, probability density function, and power spectral density are discussed. For the MOIT jet mixer with large jet-to-crossflow velocity ratios, direct impingement of the jets enhances the mixing by speeding up the evolution of the counter-rotating vortex pairs, resulting in reduction in the vortex scale, increasing the vortex magnitude, and homogenizing the vortex distribution. The effect of the mixer scale-up on the turbulent characteristics was also studied. Moreover, we selected a specific MOIT jet mixer to perform optimization of the...

Multiple orifices and cholangiography with a “fire-like” appearance after Kasai hepatoportoenterostomy for biliary atresia

A 21-year-old female underwent a Kasai hepatoportoenterostomy with Roux-en-Y reconstruction for typeIII biliary atresia at age 63 days. At the age of 19 years, she developed cholangitis and CT scan revealed hepatolithiasis. She presented for treatment of the intrahepatic stone and the hepatportoenterostomy was directly visualized with double-balloon endoscopy (DBE). Endoscopic findings showed multiple intrahepatic bile ducts open to the jejunum through multiple orifices. Cholangiography showed narrowing of intrahepatic bile duct branches with a "fire-like" appearance. These findings have not been previously reported, since endoscopic approaches to patients with a hepaticojejunostomy were limited. DBE was useful to directly visualize the anastomosis in a patient status-post the Kasai operation for biliary atresia with a Rouxen-Y reconstruction.

On the performance and flow characteristics of jet pumps with multiple orifices.

The design of compact thermoacoustic devices requires compact jet pump geometries, which can be realized by employing jet pumps with multiple orifices. The oscillatory flow through the orifice(s) of a jet pump generates asymmetric hydrodynamic end effects, which result in a time-averaged pressure drop that can counteract Gedeon streaming in traveling wave thermoacoustic devices. In this study, the performance of jet pumps having 1-16 orifices is characterized experimentally in terms of the time-averaged pressure drop and acoustic power dissipation. Upon increasing the number of orifices, a significant decay in the jet pump performance is observed. Further analysis shows a relation between this performance decay and the diameter of the individual holes. Possible causes of this phenomenon are discussed. Flow visualization is used to study the differences in vortex ring interaction from adjacent jet pump orifices. The mutual orifice spacing is varied and the corresponding jet pump performance is measured. The orifice spacing is shown to have less effect on the jet pump performance compared to increasing the number of orifices.

Cannulation of the non visualised duct: Managing biliary complications after adult-to-adult living donor liver transplantation

Background: Anatomic variations of donor bile ducts may be a significant cause of post-transplant morbidity. The aim of this study is to evaluate the impact of donor biliary variations on recipients' outcome in (AALDLT). Methods: From 2008 to 2015, 420 patients underwent AALDLT with duct-to-duct biliary reconstruction. According to donor biliary anatomy, right liver grafts (RLG) were classified into 2 groups; grafts with single right bile duct (RBD) (group1, n = 254) and grafts with multiple RBDs (group 2, n = 166). duct-to-duct biliary reconstruction was done. Type I: single right bile duct to recipient's common hepatic duct (CHD); Type II: 2 right sectorial bile ducts anastomosed to the recipient's right & left hepatic ducts; Type III: ductoplasty of the graft's sectorial bile ducts anastomosed to the recipient's CHD. mean follow-up 12 months. Results: Multiple RBDs included 2 or 3 RBD in (46.7%) and (3.3%) cases, respectively. type I in 50% of cases, type II in 21.6% and type III in 28.3%. In type 1, the incidence of biliary leakage, cholangitis & stricture was 3.3%, 13.3% & 20% respectively. In group 2 recipients, the incidence of biliary leakage, cholangitis & stricture was 8.7%, 10% & 26.7% respectively. There were no statistical significant differences in early or late biliary complications. Endoscopic management was the primary treatment modality in all patients with biliary strictures and leakage. Conclusion: Biliary complications could be managed endoscopically. RLGs with multiple biliary orifices should not be prohibited as it does not penalize recipient biliary reconstruction outcome in AALDLT.

Development and evaluation of a functional bioreactor for CO fermentation into ethanol

In a conventional syngas fermentation process, gas was released into the fermentation broth through a single orifice or multiple orifices, except the hollow fiber membrane reactor. Consequently, a simplified bioreactor has been developed employing an innovative gas supply and effluent extraction systems. A continuous stirred tank bioreactor (CSTBR) has been developed by incorporating an innovative gas supply and effluent extraction system to ferment syngas into ethanol. The working volume of the bioreactor was controlled to 2 L. The CO gas was fermented in the developed bioreactor by using a microorganism (Clostridium ljungdahlii) with different gas (5–15 mL/min), media, and effluent flow rates (0.25–0.75 mL/min) and stirrer speed (300–500 rpm). Gas was diffused into the fermenting broth through an aqueous aeration tube commonly used in the small household aquarium, placed at the bottom layer throughout the periphery. The effluent was extracted from the top layer of the broth by using a membrane separator. Ethanol and acetic acid concentrations were varied from 0.17–1.17 and 8.50–23.68 g/L-effluent, respectively. It seems that the performance of CSTBR can be enhanced with an innovative gas supply system, which may reduce the gas bubble size and result in higher lateral velocity at the releasing point, especially, throughout the periphery instead of the center of the reactor through a single or multiple orifice.

A Study on the Dynamic Performance for Hydraulically Damped Rubber Bushings with Multiple Inertia Tracks and Orifices: Parameter Identification and Modeling

Hydraulically damped rubber bushings (HDBs) are important for vehicle noise, vibration, and harshness (NVH) performance as they are able to decay the vehicle’s oscillation induced by engine and road. The dynamic stiffness and loss angle of an HDB are crucial and it is significant to investigate the relations between the design parameters with the dynamic stiffness and loss angle. Therefore, the force-deflection relation of the HDB is measured statically and the dynamic stiffness and loss angle are measured dynamically and the test data are analyzed with a view to examine how the measurement results are influenced by the design parameters (the number of the fluid tracks). Compared with the results predicted by a nonlinear lumped parameter model whose parameters are extracted by a parameter identification technique, using the model, the effect of the main rubber and the fluid track on the dynamic stiffness and the loss angle is investigated. A unified analytical model of HDB is also developed with the purpose of predicting the static and dynamic characteristics, and the predictions are shown to be well correlated with the measurement data. The good correlation suggests the validity of the model and the parameter identification implementation.

Design relation and end correction formula for multi-orifice Helmholtz resonators with intrusions

Helmholtz resonators are used to control low-frequency noise in cavities. One of the ways to reduce the resonance frequency of a resonator without changing its volume is to introduce an intrusion. Similarly, the introduction of multiple orifices can increase the resonance frequency without changing the resonator volume. These features provide an ability to accommodate slight changes in the cavity/enclosure frequencies during the design process. However, one has to rely on extensive three-dimensional finite element or boundary element simulations to predict the resonator characteristics with the introduction of these features. To reduce the computational burden, a design relation, between the first resonance frequency of a single orifice intruded resonator with that of a multi-orifice intruded resonator, is proposed in this paper. In developing this design relation, the total cross-sectional area of the resonator with multiple orifices is the same as that of the single orifice resonator. It is shown that this design relation is independent of the shape/size of the orifices and resonator cavity. Using this relation, a new end correction formula for the orifice lengths of multi-orifice intruded resonators has been proposed. The end correction formula can be used to calculate the reactance of multi-orifice intruded Helmholtz resonators analytically. These expressions are derived by carrying out extensive simulations of the resonators using the boundary element method. Limited experiments have been carried out to validate the proposed approach. The use of these expressions will reduce the computational cost of simulating cavities embedded with resonators as one can avoid modeling the resonators and use impedance boundary conditions instead.

Endodontic management of middle mesial canal in mandibular first molar

Deviations from the norm such as multiple orifices, apical deltas, accessory canals, and other variations are frequent in the roots of the posterior teeth. Two clinical reports of mandibular molars are presented in which three canals in the mesial roots were treated endodontically. Review of the literature encountered a prevalence ranging from 1% to 15%. Clinically, the third canal is difficult to find and exhibits a very variable morphology, which may present anastomosis with the other canals.

Flow of granular matter in a silo with multiple exit orifices: jamming to mixing.

We investigate the mixing characteristics of dry granular material while draining down a silo with multiple exit orifices. The mixing in the silo, which otherwise consists of noninteracting stagnant and flowing regions, is observed to improve significantly when the flow through specific orifices is stopped intermittently. This momentary stoppage of flow through the orifice is either controlled manually or is chosen by the system itself when the orifice width is small enough to cause spontaneous jamming and unjamming. We observe that the overall mixing behavior shows a systematic dependence on the frequency of closing and opening of specific orifices. In particular, the silo configuration employing random jamming and unjamming of any of the orifices shows early evidence of chaotic mixing. When operated in a multipass mode, the system exhibits a practical and efficient way of mixing particles.

Optimization of interventions in ebola: differential contagion.

Managing any contagious infectious disease outbreak involves breaking the chain of transmission from those who are infected with the pathogen to those who are not. Not all pathogens, however, are equal in their contagiousness, and considerable variation exists. The viral disease measles, for example, is considered to be one of the most contagious human diseases. Its high rate of contagion is driven by 2 attributes: the ability to spread through the air via small particles (ie, airborne transmission) and the fact that one of the symptoms of measles is coughing, an effective means of expelling those particles. On average, a person infected with measles can infect 15 other people through the course of his or her illness.1 Diseases like tetanus and anthrax, on the other hand, are not contagious at all because they lack the ability to spread between humans. In between these 2 extremes lie all the other infectious diseases. Another factor that affects infectiousness is the course of illness. Disease symptoms such as coughing, vomiting, and diarrhea can serve to heighten the transmission of a pathogen. For example, a person with whooping cough is more contagious when he is coughing than when he is not because the expelling of infectious material renders him more contagious. Ebola viral disease (EVD) is no different. Ebola is spread exclusively through blood and bodily fluids. Thus, those Ebola patients experiencing symptoms of vomiting and diarrhea—because they are literally expelling infectious bodily fluids—would be expected to be more contagious than those without these symptoms, who may have less opportunity to spread the illness. Another feature of Ebola is the hemorrhagic manifestations that occur in approximately half of patients. This often terminal manifestation includes bleeding from multiple bodily orifices, IV sites, needle punctures, and gums. An individual who is hemorrhaging, much like the vomiting patient, would be expected to be more contagious since viral particles are being emitted into the environment from the patient's body via blood. The phenomenon of varied contagiousness was seen in the 1972 smallpox outbreak in the former Yugoslavia, in which 1 individual with hemorrhagic smallpox spread the virus to 38 contacts. Other victims transmitted infection to only 2 to 3 others.2 If this differential contagiousness occurs with Ebola as well, it could be employed to optimize isolation and contact tracing activities—essential in a resource-challenged setting such as West Africa. If those individuals with hemorrhagic disease, vomiting, and diarrhea are the most infectious, then infection control should be prioritized to ensure that these patients are cared for with the appropriate protective measures in place. When contact tracing activities are performed, prioritizing the location of those who had contact with such cases could occur. Close contacts should be identified whenever possible and either kept under surveillance throughout 1 incubation period or provided preventive vaccination or treatment, as appropriate when available. Additionally, each case of Ebola identified should prompt a concurrent epidemiologic investigation to identify the source of the particular infection. Such actions ensure that primary cases are still being identified and also assess the efficacy of control measures such as isolation. The approach outlined serves to focus response efforts on activities anticipated to have the highest impact on slowing disease transmission by allocating scarce epidemiologic and infection control resources optimally.

Order of orifices: sequence of condom use and ejaculation by orifice during anal intercourse among women: implications for HIV transmission.

For women, the order of penile insertion, condom use, and ejaculation by orifice during sexual events affects the probability of HIV transmission and design of HIV prevention methods. From October 2006 to June 2009, 431 women in Los Angeles and Baltimore in a rectal health study reported the sequence of penile insertion, condom use, and ejaculation by orifice location by computer-assisted self-interview. Multinomial logistic regression identified predictors of condom use by orifice among women who reported vaginal intercourse (VI) during their last anal intercourse (AI) event. Of the 192 reporting on a last AI event, 96.3% (180/187) reported VI. Of these, 83.1% had VI before AI. Including the 36% who ejaculated in both the rectum and vagina, 66% report any ejaculation in the vagina and 45% in the rectum. One-third used a condom for both VI and AI, <10% for VI only or AI only, and half used no condoms. After adjusting for race, partner type, and substance use, compared with women who used condoms for both VI and AI at last AI, being older (units = 5 years) [adjusted odds ratio (AOR) = 0.76; 95% confidence interval (CI): 0.60 to 0.96], with serodiscordant partners (AOR = 0.22; 95% CI: 0.08 to 0.61), and HIV-positive with seroconcordant partners (AOR = 0.15; 95% CI: 0.04 to 0.54) were associated with not using condoms. For most of the women in our study VI accompanied AI, with AI usually occurring after VI. This evidence for use of multiple orifices during the same sexual encounter and low use of condoms across orifices supports the need for a multicompartment HIV prevention strategy.