Cavity Pressure Research Articles

Interpretation of the effect of transient process data on part quality of injection molding based on explainable artificial intelligence

This paper proposes an interpretation methodology for the effect of transient process data on quality of injection molded parts. The transient process data measured in the actual processing space have been regarded as the most relevant information to manufacturing processes and product quality. However, its interpretation to pinpoint which feature in the data would affect part quality has traditionally relied on knowledge and understanding of the manufacturing process. The main objective of this method is to reduce the dependency of the transient process data analysis on process knowledge and understanding by using explainable artificial intelligence (XAI). The contribution of the ‘section-wise' features in the transient process data to the quality prediction of machine learning (ML) models was investigated for the first time. The interpretation results of the effect of cavity pressure and mold surface temperature on four different quality factors represented reasonable explanations of the characteristics of the polymer materials, product geometry, and molding process. Due to the intermediate relationship of the transient process data with the user-specified process parameters and the resulting quality variables, the interpretation results can be further utilized to optimize the process and provide the optimal transient process data profile for best part quality.

Performance of asphalt shingles under simulated hurricane winds and evaluation of current installation practices

This paper investigates the wind resistance of asphalt shingles, evaluates the efficiency of their current installation methods, and addresses the lack of a system-level resistance metric from a wind engineering standpoint. The study examined the wind performance of asphalt shingles considering three installation practices recommended in high-velocity wind areas and three nailing non-conformities due to workmanship issues by conducting full-scale failure assessment tests at the NHERI Wall of Wind Experimental Facility. Roofing Application Standard (RAS) No. 115 and FEMA's recommended practices, with and without modifications, were used as recommended practices; while missing nails, over-driven nailing, and high-nailing cases were simulated as installation deviations or errors. Monoslope, gable, and hip roof decks were also used to study the contribution of roofing geometries. The results showed that asphalt shingles installed using methods recommended by the current guidelines may be vulnerable to wind flows from critical directions. Asphalt shingles, tested in the current work, experienced failure at wind speeds below their design level, especially due to cavity pressurization. Nailing non-conformities were also observed to compromise shingles' performance. Additionally, asphalt shingle failure modes, extents, and areas varied with roof geometries and the employed installation methods.

Experimental study on tail cavity structure and pressure characteristics of underwater vehicle with tail jet

The tail of an underwater vehicle with a tail jet often creates an attached tail cavity when moving at high speed. The strong coupling between the tail cavity and high-speed jet affects the kinematics characteristics of underwater vehicles. This paper compares the influence of Froude number (Fr) and ventilation coefficient (CQv) on the tail cavity at area ratio A/Ae = 92.5 and 236.7 by water tunnel experiment. It was found that at a small Fr, the critical ventilation coefficient of the transition from intact (IC) to partially broken (PBC) and PBC to pulsating foam (PFC) at A/Ae = 92.5 is greater than that of A/Ae = 236.7. The cavitation number (σc) at A/Ae = 92.5 is generally smaller than that of A/Ae = 236.7. With increased CQv, PBC's dimensionless time-averaged length (Lc‾/D) decreases sharply and then gradually flattens. The Lc‾/D of A/Ae = 236.7 is larger than that of A/Ae = 92.5. The fluctuation amplitude of the PBC length is smaller than that of the PFC, and the fluctuation frequency (fLc) of the PFC length is about 120 Hz. The change in the tail cavity will affect the pressure characteristics of the vehicle's bottom. With the increase of CQv, the peak frequency of the bottom pressure fluctuation (fpeak) will continue to rise in the PBC until the transition to the PFC, and the fpeak will remain at about 120 Hz. The correlation coefficient is 0.74 between the fLc and the fpeak. In addition, the pressure oscillation intensity at the vehicle's bottom (pbrms) is small in the IC region. When the tail cavity changes from PBC to PFC, pbrms increases gradually at first, then tends to be flat.

Analytical and experimental studies for the vibration transmission of the double-plated structure containing the inner fluid and elastic connections

The vibration transmission of the double-plated structure containing the inner fluid and elastic connections are researched by the analytical and experimental techniques. An analytical method is firstly proposed to predict vibration responses of the double-plated structure. The improved Fourier series are used to describe the transverse displacements of the plates and the sound pressure of the acoustic cavity. The elastic connections are regarded as springs. Motion equations are derived by the energy method and vibration results are gained via the Rayleigh–Ritz technique. Meanwhile, a test sample of the double-plated structure is manufactured. Four vibration isolators are utilized as the elastic connections. The inner fluid is air or water. Forced vibration tests are conducted with a random white-noise force. The results from both experiments and the finite element method (FEM) are well consistent with ones calculated by the analytical method. Then the effects of important parameters on the vibration transmission are studied by the analytical and experimental analyses, including the stiffness of elastic connections, the height of the inner fluid, the boundary condition of plates, the spring position, the inner fluid loading and the coating damping layer. It is found that the inner water acts as a short circuit in the vibration transmission, and the inner air leads to the less vibration transmission from the upper plate to the lower one. Some other new phenomena are also observed and analyzed in this paper.

V-033 MINIMAL INCISION REPAIR OF RECTUS ABDOMINIS MUSCLE DIASTASIS (MIRRAD) AS DAY CASE SURGERY: A PILOT STUDY

Abstract Rectus abdominis muscle diastasis (RAD) is a common condition where the rectus muscles are separated by an abnormal distance causing widening of the linea-alba. This condition usually occurs due to increased abdominal cavity pressure. The most common causes are pregnancy and truncal obesity. There is also an increased risk of hernia in the linea-alba. Some of the patients with RAD can increase the stability with the abdominal wall muscle-training program, while others do not benefit from this type of exercise. There is no consensus yet regarding the preferred surgical treatment. The need for a minimal invasive surgical procedure as a day case surgery in RAD in selected cases is obvious. The aim of this study is to evaluate the safety and effectiveness of MIRRAD as a day case surgery. All patients are planned as elective day case surgery. Through a small skin incision on one side of the umbilicus, the subcutaneous fat is undermined and dissected from the external aponeurosis 7–9 cm above and 5 cm below the umbilicus to expose the diastasis. The umbilicus is de-attached from the external fascia. The abdominal rectus muscle diastasis is then plicated with double layer barbed suture. The umbilicus re-attached and skin sutured. Results 20 patients are repaired with this method, all as a day case surgery, without any immediate complication. Conclusion This new, relative simple, method is cost effective and may minimize the postoperative morbidity. The method may preferably appropriate for patients without excessive skin.

Modeling and simulation of bulk viscoelasticity for amorphous polymers in injection molding

Bulk viscoelasticity is not well studied and understood in the field of polymer processing. Its behavior in solid mechanics applications, such as time-dependent bulk modulus and time-dependent thermal expansion, was rarely considered but started to receive attention recently. Bulk viscosity (bulk viscoelasticity in fluid mechanics formulation) has been ignored in polymer processing for decades. Bulk viscosity could play an essential role in compressible polymer melts that undergo substantial volume changes caused by variations in temperature and mechanical pressure during fluid motion and solidification. This study investigates the bulk viscosity of an amorphous polymer, polystyrene (PS), through measurements, modeling, and implementation in an injection molding simulation. Simulation results of cavity pressures and shrinkages are validated with experimental data in a three-plate mold case (part size 300 × 100 × 3 mm3). Results demonstrate that the effects of bulk viscosity reduced mechanical pressure variations during the packing stage in injection molding. However, the cavity pressure predicted by GNF (generalized Newtonian fluid) models with bulk viscosity drops too fast during the holding stage. The current GNF model can neither accurately describe isothermal pressurization (bulk creep) experiment data. A three-element-based constitutive model is proposed to describe bulk viscoelasticity in isobaric cooling and isothermal pressurization PVT (pressure-specific volume–temperature) measurements. This proposed model's predictions of cavity pressure, part weight, and shrinkage agree with the experiments and show significant improvement over the GNF model.

Accidental gunshot injury with left-sided lung injury and D11 burst fracture: a case report.

We present a case of an accidental gunshot injury (GSI) to the chest resulting in left-sided hemopneumothorax, left lung contusion, and D11 burst fracture with spinal cord injury. The patient underwent thoracotomy to remove the bullet along with instrumentation and fixation of the D11 burst fracture. Penetrating trauma to the chest requires prompt resuscitation and stabilization with eventual definitive care. Most GSIs to the chest require chest tube insertion, which helps to create negative pressure in the chest cavity, allowing adequate time for the expansion of the lungs. GSIs to the chest could give rise to life-threatening conditions. However, the patient must be stabilized for at least 48h before performing any surgical repair to ensure that there are fewer complications following surgery.

Surface Modified Optical Fiber Fabry–Perot Cavity Pressure Sensor With Carbon Film

By the method of pulsed laser deposition of a Ni/C bilayer precursor films and annealing in air, amorphous carbon films were prepared on the surface of the capillary used for fabrication of optical fiber Fabry-Perot (FP) cavity pressure sensors. The surface morphologies of the coated and annealed carbon films were investigated through scanning electron microscopy. The images reveal that surface modification smoothes the irregular particles on the capillary surface and releases the stress induced by carbon and nickel deposition and oxy-hydrogen flame welding. Performance tests showed that the surface modified pressure sensors have good linearity for pressure response and the cavity length variations during the full cycle of pressure change is within 31 nm. Furthermore, thanks to the introduction of carbon films, the long-term stability of the cavity length can be kept within 10 nm during the tested 150 days.

PO-01-060 HEART FAILURE DUE TO DIASTOLIC MITRAL REGURGITATION AND BRADYCARDIA SECONDARY TO BLOCKED BIGEMINAL PREMATURE ATRIAL CONTRACTIONS AFTER DEVICE CLOSURE OF PATENT FORAMEN OVALE

Diastolic mitral regurgitation (DMR) may occur due to an increased left ventricular (LV) cavity pressure compared to the left atrial (LA) pressure. This may occur with bradycardia when diastolic filling time is increased. In our case, the patient was found to have blocked bigeminal premature atrial contractions (PACs) causing bradycardia leading to diastolic mitral regurgitation. N/A N/A A 58-year-old woman presented with one week history of shortness of breath, paroxysmal nocturnal dyspnea, lower extremity edema, and weight gain. Past medical history was remarkable for transient ischemic attack and closure of patent foramen ovale with 30-mm Gore device. Examination was remarkable for bradycardia, elevated JVP and peripheral edema. Electrocardiogram showed bradycardia secondary to blocked bigeminal premature atrial complexes (PAC) [Fig A]. Transthoracic echocardiogram demonstrated diastolic mitral valve regurgitation [Fig B]. Cardiac catheterization showed normal coronary arteries. She was treated with intravenous furosemide for volume management. Bradycardia was paradoxically treated using nadolol 20 mg daily for suppression of PACs after which the patient’s symptoms were stabilized. DMR is usually seen in complete heart block due to reversal in atrioventricular pressure gradients. Interestingly, in our case, non-conducted PACs which caused significant bradycardia were responsible for DMR. PAC morphology was consistent with septal origin. We propose that the likely etiology of septal PACs is the impingement of septal occluder device on the non-coronary sinus and retro-aortic atrial septum.

Steady and unsteady flow characteristics of dual cavity in strut injection scramjet combustor

This study aims to understand the flow performance of a dual wall-mounted cavities in a strut-injector mounted scramjet combustor for steady-state and transient reacting conditions. Conventionally, two-dimensional Reynolds Averaged Navier-Stokes approach is adopted to compute the steady flow, whereas the current research employs Delayed Detached Eddy Simulation for predicting the unsteady flow characteristics as well. The calculated flow patterns, density, pressure, and temperature fields of dual cavities are compared with shadowgraph and wall pressure measurements from DLR experiments. The dual cavities position substantiates to explore the interplay between wave propagation and shear layer mixing characteristics. Employing a dual cavities arrangement accelerates toward the complete combustion relative to the baseline model. The combustion zone widens in the lateral direction as the dual cavities shift the shock train downstream of the strut injector owing to intense shock shear layer interactions. These cavities' existence significantly modifies the dominating frequencies and affects the strength of the diverging section's coherent flow structures.

Impact Response of the Tail Beam Jack Based on Bidirectional Fluid-Structure Coupling Simulation.

In top coal caving mining, the coal rock collapse will cause an irregular impact on the tail beam jack of the caving control mechanism. The severe impact will lead to jack failure. The bidirectional fluid-structure coupling model is built on Fluent and Mechanical software to study the impact response of the tail beam jack. The dynamic flow velocity streamlines, hydraulic pressure distribution, stress field, and strain field of the jack under impact load are extracted. The response characteristics of the jack in the stationary state and motion state are analyzed. The conclusions are as follows: the stress and strain of the rodless cavity are much larger than those of the rod cavity, which is more likely to be damaged. The hydraulic pressure in the jack cavity is in vertical layered distribution. The flow velocity streamlines present spiral shapes. The response degree of the hydraulic pressure signal in the rodless cavity is stronger than that in the rod cavity, and the response degree of the flow velocity signal in the rod cavity is stronger than that in the rodless cavity. The impact response of the jack in the motion state is more sensitive and stronger than that in the stationary state. The coal rock collapse situation can be most effectively identified only by comprehensively analyzing the rodless cavity's pressure signal and the rod cavity's velocity signal. This paper innovatively visualizes the flow velocity streamlines and pressure distribution together. The bidirectional fluid-structure coupling method is innovatively applied to the tail beam jack. The findings of this study can help for better understanding of the tail beam jack's structural design and failure prevention. This study provides a certain research basis for the intelligent coal rock identification technology in mining coal based on jack vibration signals.

Evaluation of the injection molding process behavior during start-up and after parameter changes using dynamic time warping correspondences

Injection molding is one of the most widely used plastic processes due to its mass production capability and low production costs. Both simple and complex part geometries can be produced in short cycle times which, with other manufacturing processes, would require long production times. To control the process, it is adjusted by a variety of parameters. In addition to the machine configurations, disturbances, the thermal behavior of the machine components and the process control influence the process behavior and the resulting part quality.Due to the large number of machine parameters and the complexity of the process, it is not apparent to the machine operator how long the machine needs after switching on until the process runs stable. Up to now, the quality characteristics of the injection molded parts are determined by extensive tests in order to evaluate the process behavior. Thereby mostly the weight is used representatively as quality characteristic for process and quality control because it can be determined non-destructively, and it is closely related to other quality characteristics (such as dimensional properties).The aim of this research was to analyze the time series of the machine process data and to assess an automated method for evaluating the start-up behavior and the machine behavior after machine parameter changes. For this purpose, dynamic time warping correspondences (DTW) was used to investigate the process behavior based on high-resolution process data (here: injection pressure, flow rate, and screw volume).The method presented in this paper makes a significant contribution to automating the start-up process and reducing the testing effort. In addition, the investigations provide insightful findings for analyzing the process behavior after parameter changes. To improve the outcome, the mold temperature and cavity pressure should also be evaluated with the presented method in future investigations.

Gas Formation of Cobalt and Copper in the Application of Unconstrained Co-Cr-Al-Cu Metal Powders in Submerged Arc Welding: Gas Phase Thermodynamics and 3D Slag SEM Evidence

Aluminium metal is not typically added to the submerged arc welding (SAW) process because it is easily oxidised to form unwanted slag in the weld pool. The successful application of aluminium as a de-oxidiser is illustrated in this study by preventing oxidation of Cr and Co to their oxides, thereby preventing element loss to the slag. Unconstrained pure metals of Al, Cr, Co and Cu were applied to investigate the gas formation behaviour of these elements in the SAW arc cavity. Of interest is the effect of copper in the arc cavity in terms of its possible substitution for aluminium. The results confirmed that the Al-Cr-Co-Cu alloyed weld metal total oxygen content was lowered to 176 ppm O, in comparison to 499 ppm O in the weld metal formed from welding with the original flux, which excluded metal powder additions. This lower ppm O value of 176 ppm O confirms that the added aluminium powder effectively lowered the original flux-induced partial oxygen pressure in the arc cavity, and at the molten flux–weld pool interface. Carbon steel was alloyed to 5.3% Co, 5.5% Cr, 5.3% Cu and 4.5% Al at 78% Co yield, 82% Cr yield, 78% Cu yield and 66% Al yield. Thermochemical equilibrium calculations confirm the partial oxygen pressure-lowering effect of aluminium when considering the gas–slag–alloy equilibrium. BSE (backscattered electron) images of the three-dimensional (3D) post-weld slag sample show dome structures which contain features of vapour formation and re-condensation. SEM-EDX (scanning electron microscope-energy dispersive X-ray) maps show that the dome surface matrix phase consists of Al-Mg-Ca-Si-Na-K-Ti-Fe-Mn oxy-fluoride. The spherical 3D structures of 10–40 µm in diameter consist of Fe-Mn-Si fluorides with some Cr, Cu and Co contained in some of the spheres. Cr and Co were observed in distinctive porous structures of approximately 10 µm in size, consisting partly of Cr oxy-fluoride and partly of Co oxy-fluoride. Nano-sized oxy-fluoride strands and spheres in the dome structures confirm vaporisation and re-condensation of oxy-fluorides. Cu and Na formed a distinct condensation pattern on the surface of the Si-Cu-Na-Mn-Fe-Co oxy-fluoride sphere. The results confirm the importance of including gas phase reactions in the interpretation of SAW process metallurgy.

Microfibrillar-associated protein 5 suppresses adipogenesis by inhibiting essential coactivator of PPARγ

Femoral head necrosis is responsible for severe pain and its incidence is increasing. Abnormal adipogenic differentiation and fat cell hypertrophy of bone marrow mesenchymal stem cells increase intramedullary cavity pressure, leading to osteonecrosis. By analyzing gene expression before and after adipogenic differentiation, we found that Microfibril-Associated Protein 5 (MFAP5) is significantly down-regulated in adipogenesis whilst the mechanism of MFAP5 in regulating the differentiation of bone marrow mesenchymal stem cells is unknown. The purpose of this study was to clarify the role of MAFP5 in adipogenesis and therefore provide a theoretical basis for future therapeutic options of osteonecrosis. By knockdown or overexpression of MFAP5 in C3H10 and 3T3-L1 cells, we found that MFAP5 was significantly down-regulated as a key regulator of adipogenic differentiation, and identified the underlying downstream molecular mechanism. MFAP5 directly bound to and inhibited the expression of Staphylococcal Nuclease And Tudor Domain Containing 1, an essential coactivator of PPARγ, exerting an important regulatory role in adipogenesis.

Development of an Open-Source Injection Mold Monitoring System

In the highly competitive injection molding industry, the ability to effectively collect information from various sensors installed in molds and machines is of the utmost relevance, enabling the development of data-based Industry 4.0 algorithms. In this work, an alternative to commercially available monitoring systems used in the industry was developed and tested in the scope of the TOOLING 4G project. The novelty of this system is its affordability, simplicity, real-time data acquisition and display in an intuitive Graphical User Interface (GUI), while being open-source firmware and software-based. These characteristics, and their combinations have been present in previous works, but, to the authors' knowledge, not all of them simultaneously. The system used an Arduino microcontroller-based data acquisition module that can be connected to any computer via a USB port. Software was developed, including a GUI, prepared to receive data from both the Arduino module and a second module. In the current state of development, data corresponding to a maximum of six sensors can be visualized, at a rate of 10 Hz, and recorded for later usage. These capabilities were verified under real-world conditions for monitoring an injection mold with the objective of creating the basis of a platform to deploy predictive maintenance. Mold temperature, cavity pressure, 3-axis acceleration, and extraction force data showed the system can successfully monitor the mold and allowed the clear distinction between normal and abnormal operating patterns.

Influence of skew angle on the cavitation dynamics and induced low-frequency pressure fluctuations around a marine propeller

This study numerically investigated the effects of the skew angle on cavitation and the induced low-frequency pressure fluctuations. The numerical results compare well with available experimental data. The skew angle significantly impacts the cavitation dynamics as well as the pressure fluctuations. As the skew angle increases, the dominant cavity type gradually changes from sheet cavitation to tip vortex cavitation and the cavitation on the blade passing through the wake flow is delayed. Fast Fourier Transforms combined with Wavelet Transforms were applied to explore the relationship between the cavity volume acceleration and pressure fluctuations for various skew angles. The low-frequency pressure fluctuations around the propeller are mainly related to the first blade passing frequency (BPF) and its harmonics. The sheet cavity collapse significantly enhances the interaction of the low BPF components, while the tip vortex cavity collapse has the opposite effect. In addition, large skew angles weaken the interaction of the low BPF components which reduces the low-frequency pressure fluctuations.

Nitriding Behaviour and Microstructure of High-Nitrogen Stainless Steel during Selective Laser Melting.

High-nitrogen stainless steels are widely used due to their excellent comprehensive performance. In this study, the effects of process parameters (laser power, scanning speed, and cavity pressure) on the formation of high-nitrogen stainless steels were studied by using conventional selective laser melting and high-pressure selective laser melting (HPSLM). The nitrogen content, nitrogen emission, phase composition, microstructure, and microhardness of the high-nitrogen stainless steel samples obtained through selective laser melting (SLM) were analysed by using an oxygen/nitrogen/hydrogen analyser, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction. The results showed that the maximum nitrogen emission in the SLM sample was 0.175 wt.%, the emission rate reached up to 54.7%, and the maximum nitrogen content in the HPSLM sample was 1.07 wt.%. There was no significant difference between the phase peak positions of the SLM samples with different laser powers and the original powder. The main phase of the HPSLM sample changed at 0.3 MPa (from α-Fe to γ-Fe phase); the microstructure of the SLM sample was mainly composed of columnar and cellular crystals, and columnar crystal bands formed along the direction of heat flow. The HPSLM sample was mainly composed of equiaxed crystals with a grain size of 10-15 μm. At an energy density of 136 J/mm3, the microhardness and relative density reached their peak values of 409 HV and 98.85%, respectively.

A combined finite-discrete element model for elasto-capillary phenomena

Elasto-capillary phenomena, involving finite deformation of elastomer and elasto-capillary effect of droplet/film, widely exist in biological and micro-electro-mechanical systems. To quantitatively analyze the influence of surface tension and to accurately predict the deformation of elastomer, we develop a finite strain model of hyperelastic materials, and then solve it by the explicit dynamics employing the combined finite-discrete element method (FDEM). Based on our model, we investigate the expansion of a small cavity in elastomer and examine the relation between radius and pressure of cavity. Besides, we explore the deformation of an elastic rod that is immersed in liquid and subjected to surface tension. Results show that when the elasto-capillary effect is neglected, edges of the rod would be unrealistically roughened, while the surface is actually smoothed as the surface tension increases. Moreover, we explore the elasto-capillary effect on advanced multiple-period wrinkling patterns in both planar and curved film–substrate systems, showing that the rough wavy surface can be smoothed by increasing surface tension. Our results not only provide fundamental insights into a variety of elasto-capillary phenomena, but also offer a platform to quantitatively guide rational designs of flexible smart devices actuated by surface tension.

サブマージアーク溶接中の壁面移行形態の二次元粒子法シミュレーション

The flux-wall guided transfer mode in submerged arc welding was mo deled by a particle method and simulated in two dimensions. Moreover, numerical experiments were conducted to investigate the effect of driving forces acting on the molten metal on this transfer mode. As a result, the flux-wall guided transfer was successfully simulated, in which the molten metal droplet left the wire tip while impacting a cavity wall. This computational result showed that a liquid column was formed at the wire tip by the Lorentz force, and then the column was pushed up by the cavity pressure and grown horizontally. Then, molten metal droplets collided with the cavity wall, detached from the wire tip, and were transported toward weld pool and base metal. In addition, from numerical experiments using this computational model, it was suggested that both Lorentz force and cavity pressure were important factors for this metal transfer mode.

Design optimization of a rotating packed bed based on dry hydraulic performance

The current study focuses on enhancing the fidelity of the hydraulic performance of Rotating Packed Beds (RPB) by modifying the conventional geometrical construction of the inner cavity, outlet pipe, and its packing. RPB technology has been playing an increasing role in intensifying different petrochemical processes, such as CO2 capture, due to the potential of a several-order-of-magnitude mass transfer enhancement induced by the HiGee field. In this context, four novel geometries of the RPB are proposed and analyzed using a validated CFD model that utilizes the porous media approach to model the pressure losses in the RPB packing. The impact of liquid distributor was also investigated and compared to the original design. Results of the modified geometries conclude that optimizing the flow pattern at the exit of the packing by modifying the inner cavity's shape reduces the total pressure drops by up to 22%. At the same time, it is found that a further decrease of 13% in the pressure drop can be achieved by attaching a nozzle at the entry of the outlet pipe. On the other hand, the modified packing that imposes a constant radial flow velocity increases the packing's pressure drop by 10%. Furthermore, the data analysis show that a lower pressure drop within the inner cavity could be achieved, in principle, by regulating the exit packing velocity or raising the free vortex pressure. Finally, it is noted that the gross pressure drop reduction, which is be obtained from combining the two former modifications, can reach up to 33% at the high gas volume flow rates. This reduction accounts for 60% of the inner cavity pressure drop, which can help avoid costly and complicated engineering designs.