Orifice Diameter Research Articles

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Leakage localization in an underground pressurized pipeline in steady-state

A new easy-to-implement approach based on low sampling rate sensors is proposed to estimate artificial leakage location in pressurized gas-filled pipelines. The proposed technique requires low sampling rate data and similar to some previous studies, acoustic sensors are localized on one side of the leakage. Previous studies have mainly placed sensors on both sides of the leakage which make it challenging to implement especially for long pipeline applications.This paper proposes a novel technique to localize artificial leakage in a buried and non-buried pipeline by implementing two simple electret microphones and attenuation analysis of recorded signals. An experimental set-up is conducted on a pressurized carbon steel pipe to validate the proposed method. The effects of pressure, orifice diameters and depth of specimen and sensor in the ground on the final result are discussed. The experimental results reveal the effectiveness of the proposed technique in low sampling rate data.

Optimization of operating parameters for spraying microbial (Bacillus thuringiensis and Beauveria bassiana) based bio-pesticide solutions for foliar application

Exposure to mechanical stresses developed due to different components of spraying system may cause permanent damage to the microbes of bio-pesticide solutions. To achieve maximum effectiveness of spray application, proper selection of nozzle size and operating pressure is critical. Two different classes of bio-pesticides viz. bacterial-based Bacillus thuringiensis (BBP solution) and fungal-based Beauveria bassiana (FBP solution) were evaluated for spray application by three hollow cone nozzles (1.14, 2.35 and 3.56 mm in diameter) at four operating pressures (145, 245, 345 and 445 kPa). It was observed that viability of bio-pesticide solutions increases with decrease in operating pressure and increase in nozzle size. The nozzle orifice diameter and operating pressure of the spraying system were optimized to get desired application rate, volume median diameter (VMD) and coefficient of variation (CV) of spray for maximum microbial viability of bio-pesticide solutions. The optimized values of application rate (323.94-and 325.58 L ha−1), VMD (225.88 and 231.89 µm), CV (84.49 and 85.99%) and viability (6.63 × 106 and 6.06 × 106 cfu ml−1) were obtained for BBP and FBP solutions, respectively at nozzle orifice size of 3.56 mm and 145 kPa operating pressure.

Morphological variations of vermiform appendix: A cadaveric study

: A common and deadly cause of sudden abdominal discomfort is acute appendicitis. The surgeons frequently had trouble locating the vermiform appendix in its regular location. For an effective therapy, a thorough analysis of the vermiform appendix's various locations is required. The objective of this study is to investigate and compile extensive anatomical data on the location variation of the vermiform appendix in the cadavers of western Indians. The structure's morphometry was determined. The study of appendix was carried out on 25 cadavers available in the department of anatomy. Metrical parameters such as length, diameter and distance of appendicular orifice from ileum were measured. The different positions of appendix in and the variations of the mesoappendix were noted. Mean and standred deviations were calculated.: Length of appendix was 5.47± 1.59, diameter at base was 6.85±1.82, diameter at tip was 3.94± 1.11, distance of appendicular orifice below ileum was 1.14±0.85 and Distance of appendicular orifice below ileum inside was 2.19 ±0.78 The most common position of mesoappendix was mesoappendix reaches the tip 37 (74%) followed by mesoappendix does not reaching the tip was 13 (26%).The most common position was retrocaecal 20(40%) followed by pelvic 15 (30%) least common was midinguinal. From various positions of vermiform appendix we can understand the possible outcome of the appendicitis specifically location of site of pain.

All surgical supra-annular aortic valvar tissue prostheses are labelled too large.

Surgical supra-annular aortic valvar tissue prostheses are labelled in an inconsistent and confusing manner. This increases the risk for patient prosthesis mismatch (PPM), when the replaced valve is too small for a given patient, which is associated with the risk of morbidity and mortality. Labelled diameter (LD) of these valves should coincide with inflow orifice diameter (IOD). Therefore, we set out to measure all relevant IOD's. Valvar design was assessed as to their intended position in relation to the patient's annulus. IOD's of all available supra-annular aortic valvar prostheses were measured using a conical gauge. IOD's were compared to LD's. We searched for instructions for use, websites, packing boxes and regulatory institutions involved in the process. Eight valve models of four manufacturers were included. None of these valves were clearly labelled as supra-annular on the packing box, although in three this could be found in the specifications. All valves had an IOD smaller than their LD, with a median difference of 15%, range: 4% - 25%. The departure from LD differed per valve model and valve size. Valve packages should be labelled accurately and clearly for surgeons to make a well-informed choice. Currently essential information is missing, since intended position in relation to the annulus is not consistently marked on the packing boxes, and valve sizes are labelled incorrectly. We propose a change for the better, and relabelling of all valves according to their true IOD in a structured manner.

Control of opening duration in a pneumatically operated valve with two-fluid combination and quadratic damping

In this paper, opening characteristics of a pneumatically operated valve and methodology for controlling the valve opening duration have been investigated through numerical simulation. The valve has a poppet mounted with spring which is actuated by a pneumatic command pressure to provide a displacement of 30 mm in fully open condition. The spring housing comprises of columns of two fluids, namely air and oil, and an orifice which communicates with an adjacent auxiliary chamber. As the poppet is actuated, air initially passes through the orifice leading to a fast opening of the valve. Subsequently, opening rate of the valve is reduced as oil column encounters the orifice. The governing differential equations of motion for the valve poppet were solved using a fourth-order Runge–Kutta method, and the resistance offered by the orifice to oil flow was considered using a quadratic damping model. Simulations were carried out for two different orifice sizes, and results were validated with experiments. It was noted that for the same valve assembly, the opening duration can be controlled by varying the length of oil column and/or the orifice diameter, with no change in command pressure.

Experimental Study on Spray Cooling Heat Transfer of LN2 for a Large Area

Spray cooling has been considered one of the most promising thermal control methods of high-heat flux devices. Most of the spray cooling research focuses on electronic components as the main application object to achieve higher heat dissipation heat flow in ambient temperature regions for small areas. Water is the most common cooling medium. This paper investigates the application of spray cooling thermal control over large areas. In this study, the heat-transfer characteristics of liquid nitrogen (LN2) for large areas was investigated by conducting experiments. The test surface is 500 mm × 500 mm, which was cooled by a nine-nozzle array. The spray nozzles used in the experiment were conical nozzles with an orifice diameter of 1.6 mm, a spray angle of 120°, and a spray height of 42 mm. Liquid nitrogen was forcefully ejected from nozzles by the high pressure of a liquid storage tank to cool the test surface. According to the cooled surfaces, spray directions, and spray pressures, three groups of experiments were conducted. The results showed that the smooth flat surface has the best heat-transfer performance in three kinds of surface structures, which are macro surface, porous surface, and smooth flat surface. The heat-transfer coefficient varied by ±20% with different spray directions, and the surface heat-transfer coefficient increased linearly with increasing spray pressure. Most of the spray cooling research focuses on heat dissipation in the ambient temperature region for equipment over small areas. The results can benefit thermal control application in various fields. The research in this paper can provide a reference for the application of large-area spray cooling, and the application areas mainly include metal manufacturing processing cooling, aircraft skin infrared radiation characteristics modulation, and laser weapon equipment cooling.

Solution of the Inverse Problem of Calculating a Gas–Liquid Injector with a Two-Phase Flow

We consider the possibility of solving the inverse problem of calculating a gas–liquid jet injector with a bubbly two-phase flow structure. The parameters governing the injector operation, such as the pressure difference, the orifice diameter, and the air concentration, are determined for the given value of the mean Sauter diameter. For this purpose, the operation of a mixer with a two-phase working body and injectors of different diameters was experimentally investigated in the bubbly operation regime with a water–air working body. In the experiments the parameters of the phases supplied to the mixer (flow rates, pressures, and temperatures) were measured, together with the pressure ahead of the injector. The dispersity and velocity parameters in the spray were measured using the laser shadow method. The statistics thus gathered allow one to obtain the required correlation dependences which makes it possible to solve the problem formulated.

StomachSim: An in-silico simulator of gastric biomechanics with application to pyloroplasty

Aim: We have developed StomachSim, an in-silico simulator that is designed to simulate the biomechanics and fluid mechanics of a wide range of gastric conditions as well as gastric surgical procedures. Here we demonstrate its use in quantifying the effects of motility disorders and pyloroplasty on the hydrolysis and emptying of a liquid meal inside the stomach. Methods: A physiologically realistic model of the stomach, including the antral motility, is synthesized based on in-vivo imaging, and the mixing and gastric emptying are simulated using computational fluid dynamics (CFD). The enzymatic biochemistry for protein hydrolysis is also implemented by incorporating the secretion of a proteolytic enzyme from the proximal stomach walls and the subsequent enzymatic reaction with the protein dissolved in the liquid meal. Using this model, we measured the effect of stomach motility and the diameter of the pyloric orifice on the retropulsive and pyloric jets, the rate of hydrolysis in different regions, and the emptying of gastric contents. Results: This study presents a proof-of-concept for the application of StomachSim in gastric disorders and surgeries. The emptying rate of our model for the healthy case agreed with the in-vivo measurements of similar caloric density liquid meals. A stomach with a 50% lower motility amplitude had a 35% lower net emptying rate and a 41% lower emptying rate of the hydrolyzed protein. Furthermore, the emptying rate showed a non-linear variation with respect to the motility of the stomach. For a simulated pyloroplasty procedure where the pyloric orifice diameter is doubled and the orifice stays open permanently, the emptying rate of the lower motility case doubled over its original value. Conclusion: StomachSim offers a novel and potentially effective modality for examining the effect of gastric conditions and gastric surgical procedures on gastric function. Our simulations show that gastroparesis and pyloroplasty not only affect the emptying rate but also alter the mixing of contents thereby changing the rate of hydrolysis. The model helped quantify the changes in the flow of contents in the antro-duodenal region for varying degrees of gastroparesis and pyloroplasty. The authors acknowledge support from NSF award CBET 2019405 and NIH award 1R21GM139073-01. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Influence of orifice thickness on the flow field of co-flow jets

The present study analyses the numerical simulation results of subsonic flow through co-flow orifices. Analysis is done on the effects of modifying orifice thickness on the co-flow jet characteristics. The combined frontal area of the co-flow jet and central jet is maintained constant (20 mm2). The primary orifice diameter (D) is kept as 3mm and the orifice thickness, i.e the co-flow jet is formed as four segments of a concentric circle around the core jet, and the edge distance between them ranges from 0.16D to 0.5D. The 0.16D co-flow is shown to lengthen the potential core of the main jet at nozzle pressure ratios of 1.2, 1.4, 1.6, and 1.8, but the 0.33D co-flow and the 0.5D co-flow shorten the potential core length, enhancing mixing. The present study analyses the Mach numbers that correspond to the Nozzle Pressure ratios of 1.2, 1.4, 1.6, and 1.8, which are 0.517, 0.71, 0.84, and 0.96, respectively. The 0.5D annular gap is found to be more effective which boosts primary jet mixing.

Outcome of preputioplasty in cats with acquired phimosis: Eight cases

Preputioplasty is a surgical procedure performed to increase the orifice diameter and phimosis, which is defined by the inability of the penis to extrude due to the absence or restriction of the preputial opening, is uncommon in cats. A total of eight male cats were referred to Ataturk University Veterinary Faculty Animal Hospital due to the complaint of difficulty in urination and prolonged sitting in the litter box. Narrowed preputial opening and abdominal distension were noted in all cats. The penis was too stenotic to be extruded from the preputial orifice, and urine accumulated in the preputial cavity. The serum biochemistry and hemogram results of cats were within the reference values. After the clinical examination, acquired phimosis was diagnosed. The scar tissues around the preputial orifice that prevented the extrusion of the penis were resected surgically (preputioplasty). Normal urination was recorded following preputioplasty in all cases. In one case, recurrence was postoperatively detected on the 30th day and perineal urethrostomy was performed. Preputioplasty to enlarge the preputial orifice may be used to treat acquired phimosis in cat with a low rate complication.

Thermodynamic study on throttling process of Joule-Thomson cooler to improve helium liquefaction performance between 2 K and 4 K

The Joule-Thomson cooler (JTC) is a key component of the hybrid cryocooler dedicated to achieving and maintaining the operating temperature of around 2–4 K extensively used in quantum computing and communications. To clarify the energy conversion mechanism during the throttling process of the JTC and to improve throttling performance at 2–4 K, a numerical model is developed in which the effect of the complex real physical properties of liquid helium is considered, and the modified Lee phase change model is proposed to meet the operating conditions from supercritical to saturation. The results show that the phase change causes the cooling effect during the throttling process. The larger total energy loss in orifice leads to a higher liquefaction ratio. The liquefaction ratio increases with the increasing orifice thickness and the decreasing orifice diameter and inlet pressure. Given a constant inlet and refrigeration temperature difference, the liquefaction ratio increases with the increase of inlet temperatures. The maximum liquefaction ratio of 93.80% is achieved with orifice thickness of 0.8 mm, orifice diameter of 30 μm, and inlet pressure of 0.32 MPa, assuming an inlet temperature of 4 K and a refrigeration temperature of 3.43 K.

Experimental analysis on the effect of pipe and orifice diameter in inter tank hydrogen transfer

Hydrogen is an energy carrier which can be utilized in many sectors like stationary and transportation energy with nearly zero emission. Hydrogen energy is more efficient when compared to other energy sources. Hydrogen can be a replacement for fossil fuels in future as it emits only water when it is burned. In this work a mathematical model of transfer of hydrogen between two tanks has been developed using MATLAB simulink software version 21. Flow of hydrogen inside the pipe is controlled by orifice and diameter of this orifice and pipe diameter itself has some impact on outcome parameters such as inlet temperature of pipe, outlet temperature of pipe, heat transfer from one tank to other tank and hydrogen gas flow rate. The influence of orifice diameter as well as initial pressures on outcome parameters of hydrogen gas transfer model has analyzed in this work. From the simulation results it is inferred that when one initial pressure kept constant and other initial pressure keep on varying, no change in inlet temperature, decrease in outlet temperature, increase in heat transfer and increase in gas flow rate were observed when orifice diameter increase in size from 2 cm then 4 cm and then 6 cm. The research work has significant guidance for safety and efficient way of transporting hydrogen through pipeline from one tank to other tank.

Ionization Efficiency Measurement and Optimization of a Thermal Ion Source for Radioisotope Electromagnetic Separation

An available supply of high-specific-activity radioisotopes was identified by the U.S. Department of Energy as a critical priority in the development and eventual deployment of next-generation medical diagnostic and cancer therapy tools. A radioisotope mass separator, located at the Missouri University Research Reactor Center, was developed to provide radioactive ion beams for the separation and production of high-specific-activity lanthanides used in radiopharmacology. Experiments characterizing the ionization efficiency of a thermal ion source supporting the production of high-specific-activity 153Sm are reported. With the goal of maximizing ion current while maintaining beam stability, experiments with the test ion source expand upon previously reported data from a titanium prototype ion source. Experimental results of various factors affecting ion source performance, such as diameter of the extraction orifice, ionizer geometry, ionizer temperature, and sample evaporation rate, are presented.

Asymmetric Spray Characteristics According to Y-Jet Nozzle Orifice Shape and Spray Conditions.

The Y-jet nozzle is a twin-fluid nozzle that has a larger operating range and simpler structure than other twin-fluid nozzles. Furthermore, it offers outstanding atomization quality even at low flow rates, mak ing it simple to atomize viscous liquids. However, because of the structure of the Y-jet nozzle, having an asymmetrical spray pattern is limited. Most existing experimental studies focused on the orifice diameter and mixing tube length. In this study, two types of elliptical nozzles and one type of circular nozzle were tested. We found that the elliptical nozzle's asymmetric spray characteristics are different from those of the circular type. Furthermore, it was demonstrated that the spray characteristics were different even in ellipsoids, with only the major and minor axes differing.

Numerical analysis on liquid seepage - Diffusion coupled with heat in soil of low - Pressure buried pipelines leakage

The incident of buried pipeline leakage has become one of the main concerns since the consequences of social economy and soil environment. The main objective in this study is to develop a numerical model for the low - pressure buried water pipeline leakage by CFD (Computational Fluid Dynamics). In this model, the process inside and outside of the pipeline is connected through the orifice, and the heat transfer is coupled during the leakage water seepage - diffusion in soil. In this way, the degree and diffusion range of buried pipeline leakage by considering soil as porous medium are investigated. Comparison of the numerical and experimental results demonstrated that the model has a higher precision in predicting accident severity and influencing range. Further, the effects of inlet water temperature, pipe pressure, orifice's diameter, orifice's position and soil porosity are systematically researched. Some acquired results are as follows: temperature can promote soil moisture transfer and the two are positively correlated. The degree and diffusion range increase with the increasing pipe pressure, orifice's diameter and soil porosity. Orifice's position only affects diffusion direction, not diffusion range. The conclusions will provide theoretical foundation for soil environment remediation.

Virtual reality utilization for left atrial appendage occluder device size prediction

AimTo explore the feasibility and accuracy of virtual reality (VR) derived from cardiac computed angiography (CCTA) data to predict left atrial appendage occlusion (LAAO) device size. MethodRetrospective data of patients who underwent LAAO according to clinical indication were reviewed; all patients underwent a pre-procedural CCTA. Measurements of the left atrial appendage (LAA) orifice diameters by CCTA, VR, and transesophageal echocardiography (TEE) (acquired during the procedure) were compared to the implanted device size. The LAA perimeter was calculated using the Ramanujan approximation. Statistical analyses included Lin's Concordance Correlation Coefficient (ρc), the mean difference, and the mean square error (MSE). ResultsThe sample was composed of 20 patients (mean age 75.7 ± 7.5 years, 60% males) who underwent successful LAAO insertion (ACP™ N = 8, Watchman™ N = 12). The CCTA, VR, and TEE maximal diameter ρc was 0.52, 0.78 and 0.60, respectively with mean differences of +0.92 ± 4.0 mm, −1.12 ± 2.3 mm, and −3.45 ± 2.69 mm, respectively. The CCTA, VR, and TEE perimeter calculations ρc were 0.49, 0.54, and 0.39 respectively with mean differences of +4.69 ± 11.5 mm, −9.88 ± 8.0 mm, and −16.79 ± 7.8 respectively. DiscussionA VR visualization of the LAA ostium in different perspectives allows for a better understanding of its funnel-shaped structure. VR measurement of the maximal ostium diameter had the strongest correlation with the diameter of the inserted device. VR may thus provide new imaging possibilities for the evaluation of complex pre-procedural structures such as the LAA.

Современные методы хирургического лечения пупочных грыж: обзор литературы

INTRODUCTION: In this review, methods of open and laparoscopic surgery of the umbilical hernia are described. Use of particular methods is substantiated depending on the size of the hernial orifice, the presence of hernia strangulation, diastasis of the abdominal rectus muscles, comorbidity, available technical equipment. Statistical data of complications, recurrences and of their prevention available in the literature are evaluated. The search for information was performed in electronic libraries: Pubmed, Cyberleninka. The inclusion time interval is 10 years. The keywords used in the search: umbilical hernia, IPOM, eTEP, (E)MILOS, SCOLA, tension method of hernioplasty, complications. The most important modern methods using endovideosurgical access are: laparoscopic IPOM(+), eTEP, (E)MILOS, SCOLA. Use of tension plasty can be justified in case of strangulation, but, here, recurrences are more common. The IPOM method has a number of disadvantages (adhesions, chronic pain, chronic seroma, recurrences), which make its use controversial and needing additional research. The eTEP-TAR, eTEP-RS methods are used in pronounced diastasis of the rectus muscles. The eTEP-RS method is convenient in simultaneous surgery of inguinal hernias. The eTEP-TAR method is used in case of large diameter of hernial orifice (5–12 cm), and suggested width of the retromuscular space less than 5 cm. The MILOS, EMILOS methods are used in case of primary, postoperative umbilical and epigastric hernias. With this, the frequency of complications is less relative to Sublay, IPOM. CONCLUSION: Each method of umbilical hernioplasty is based on certain factors taken into: diastasis of rectus muscles, size of hernial orifice, existence of strangulation, availability of equipment and materials, comorbid pathologies. The variety of manipulations determines personal approach in surgery of umbilical hernias. The modern tendencies in this field are minimization of injury rate in surgical approach in use of endovideosurgical access and attempts to perform simultaneous recovery of the muscular aponeurotic apparatus of the abdominal wall through elimination of diastasis of rectus muscle. Potentials of the modern high-tech medicine permit to significantly reduce the frequency of complications and recurrences in case of large, medium and complicated umbilical hernias.

Minimally invasive bilayer suturing technique for the repair of concomitant ventral hernias and diastasis recti.

According to EHS guidelines, mesh repair is recommended in case of concomitant diastasis recti (DR) and ventral hernia more than 1cm in diameter. Since in this situation, the higher risk of hernia recurrence may be attributed to the weakness of aponeurotic layers, in our current practice, for hernias up to 3cm, we use a bilayer suture technique. The study aimed at describing our surgical technique and evaluating the results of our current practice. The technique combines suturing repair of the hernia orifice and diastasis correction by suture, and includes an open step through periumbilical incision and an endoscopic step. The study is an observational report on 77 cases of concomitant ventral hernias and DR. The median diameter of the hernia orifice was 1.5cm (0.8-3). The median inter-rectus distance was 60mm (30-120) at rest and 38mm (10-85) at leg raise at tape measurement and 43mm (25-92) and 35mm (25-85) at CT scan respectively. Postoperative complications involved 22 seromas (28.6%), 1 hematoma (1.3%) and 1 early diastasis recurrence (1.3%). At mid-term evaluation, with 19 (12-33) months follow-up, 75 (97.4%) patients were evaluated. There were no hernia recurrences and 2 (2.6%) diastasis recurrences. The patients rated the result of their operation as excellent or good in 92% and 80% of the cases at global and esthetic evaluations, respectively. The result was rated bad at esthetic evaluation in 20% of the cases because the skin appearance was flawed, due to discrepancy between the unchanged cutaneous layer and the narrowed musculoaponeurotic layer. The technique provides effective repair of concomitant diastasis and ventral hernias up to 3cm. Nevertheless, patients should be informed that the skin appearance can be flawed, because of the discrepancy between the unchanged cutaneous layer and the narrowed musculoaponeurotic layer.

Influence of Pre-Chamber Volume, Orifice Diameter and Orifice Number on Performance of Pre-Chamber SI Engine—An Experimental and Numerical Study

This paper presented an experimental and numerical study of pre-chamber volume, number of orifices and orifice diameter influence on engine performance and emissions. All the measurements were performed on a single cylinder test engine at fixed engine speed of 1600 rpm, while engine load was varied by a change of the excess air ratio in the main chamber from a stochiometric mixture to a lean limit. The total of nine pre-chamber variants comprised three different pre-chamber volumes, two orifice number combinations (six and four orifices) and nine different orifice diameters. It was observed that the pre-chamber volume affects the indicated efficiency in a trend which is mostly independent of excess air ratio, with the efficiency gain between the best and worst results ranging from 1 to 4.4%. While keeping the same pre-chamber volume and the total cross-sectional area of the orifices, the larger number of orifices show better performance on two out of three investigated pre-chamber volumes, with the efficiency gains more pronounced at higher excess air ratios. Finally, on a fixed pre-chamber volume and number of orifices, the variation of orifice diameter leads to a trend in efficiency gains which favor larger orifice diameter. The comparison of the obtained efficiencies between all pre-chamber variants identified two pre-chambers, differing in each of the varied geometrical parameters, that show the best performance depending on excess air ratio range. On the other hand, a single variant which showed the worst performance on each excess ratio was identified. An additional investigation was performed by the application of the cycle-simulation model to quantify the share of emissions which are formed in the pre-chamber. The presented results showed that when PC volume is lowered, PC emission shares of NOX and CO grow larger. The influence of orifice number and size has a minor effect on the pre-chamber emissions shares. The maximum PC emission shares of 54.8% and 80.6% are achieved at lean limit (λ = 2.2) for NOX and CO, respectively. THC emission share, on the other hand, is not affected in a significant manner by either the pre-chamber geometry or operating conditions.