Pneumatic Process Research Articles

Pneumatic Catapult Performance Research Based on the True Thermodynamic Process Analysis

In the high-pressure pneumatic thermodynamic process, the pressure is much larger than the critical pressure,and the temperature deviates from the Boyle temperature seriously, the thermodynamic parameters are not authenticity under ideal gas assumption, so pneumatic performance of the quality can not be guaranteed. In view of this, the pneumatic equations are estabalised on the basis of modified corresponding state equation and improved virial equation for the high-pressure air catapult launch system, and the real dynamic thermodynamic processes are analyzed. The specific residual thermodynamic parameters of high pressure air are presented, the real thermal physical property parameters are also obtained under the wide variation conditions of temperature and pressure. The residual functions are applied to compensate the uncertainties of thermal physical property parameters, numerical experiments are performed. The comparison of the numerical results show that the value of residual enthalpy is high, the state of working fluid deviates from ideal gas; the compressibility of working fluid is strong, the compression factor reaches 1.101 3; the real gas effect accelerates the pressure and temperature decreasing rates in the hyperbaric pressure chamber, and decelerates the increasing rates in the low pressure chamber; the real work capability of hyperbaric air is lower than that of ideal gas, the overload is steady.

Two-Phase Jet in Process of Pneumatic Powder Injection into Liquid Alloy

The short description of the new approach to the pneumatic powder injection process analysis was presented in the article. The experiments with the high speed camera recording of the two-phase jet in pneumatic powder injection process were carried out in the Department of Foundry, Silesian University of Technology, Poland. The results were briefly analyzed and some interesting conclusions appeared, especially that the real velocity of the injected particles is far less than it is normally calculated with use of the well-known formulas. They were compared with existing literature data as well as with some experimentspreviously made by authors. Powder particles velocity and two-phase jet mass concentration were analyzed as the most important parameters for powder injection process. The results described are part of the complex experimental plan and the next step is computer modeling (just launched) of the jet introducing liquid.

Invaginación intestinal recurrente secundaria a apéndice cecal invaginado: Caso clínico

abstract recurrent intussusception secondary to invaginated cecal appendix. case report introduction: Intussusception is an idiopathic pathology that accounts for 95% of cases found; the remai-ning 5% is caused by some triggering events. Recurrences occur in 7 to 12% of cases and are associated with multiple causes. The aim of this research is to present the case of a patient with recurrent intussusception and analyze the cause of the recurrence. case report: The patient was a 16 month-old male infant with a history of first episode of intussusception surgery at 4 months old. His second intussusception episode took place at 9 months of age, which was treated with pneumatic reduction process; at 16 months of age he presented his third episode, which was treated with hydrostatic reduction process. 8 hours post procedure, the patient had a new intussusception condition and surgical manual reduction was performed. Ileocolic intussusception was found with an appendiceal intrathecal remnant acting as the invaginating head. Remnant was removed and sent for biopsy.

Numerical Simulation of Yarn Untwisting Mechanism in a Pneumatic Splicer Process

For better study of the airflow movement in the untwisting chamber of a pneumatic splicer, this paper uses a commercial computational fluid dynamics software FLUENT to realize the three dimensional numerical simulation for the characteristic of the airflows in the untwisting chamber. A three-dimensional grid and the realizable k- ε tur¬bulence model are used in this simulation. The characteristics of the air flows in different parts of the chamber are analysed according to the computed result. The airflow in the untwisting chamber can be divided into three regions in longitudinal section and two regions in cross section.

Three-dimensional morphometric analysis of paranasal sinuses and mastoid air cell system using computed tomography in pediatric population

ObjectivesTo evaluate the volumetric relationship between the mastoid air cell (MAC) and paranasal sinus (PNS) in the pediatric population using three-dimensional reconstruction and the analysis technique of CT. Study designRetrospective cross-sectional study was conducted at a university-based, secondary referral hospital. MethodsPNS CT imaging data of 62 children (40 boys and 22 girls; mean age=13.4±4.0 years) was reconstructed to the three-dimensional model with the surface-rendering algorithm (lower threshold of −1024HU and upper threshold of −318HU), and subsequently measuring the volume of the three PNSs (frontal, maxillary and sphenoid) and MAC. Hierarchical linear regression analysis was used to control the effect of age. ResultsControlling the effect of age, no significant linear regression relationship was found between the volume of MAC and PNSs. It was observed that PNSs and MAC showed a significant linear relationship with age. The regression slopes of PNSs were larger than that of MAC, especially the growth of maxillary and sphenoid sinuses was faster and larger than that of the frontal sinus and MAC. As the coefficient of determination was extremely small, the aging process itself could not effectively explain the volume variation of PNSs and MAC. ConclusionNo interaction was observed in the pneumatization of the three PNSs (frontal, maxillary, and sphenoid) and MAC. It was found that the growths of PNSs and MAC are influenced by age. Further, maxillary and sphenoid sinuses tend to grow faster and become larger than the frontal sinus and mastoid air cell system. Thus, it is verified that environmental factors could be involved in the postnatal pneumatization process of the PNSs and MAC, which might influence MAC to a greater extent than the PNSs.

Is pneumatization of middle turbinates compensatory or congenital?

To determine the frequency of concha bullosa (CB) and the association between the degree of pneumatization and the severity of septum deviation in both paediatric and adult groups by CT evaluation and to investigate whether the pneumatization of middle turbinates is compensatory or congenital. We retrospectively reviewed digitally stored paranasal sinus CT images of 86 paediatric and 204 adult patients. The severity of the deviation and cross-sectional area of the pneumatized area of the CB were determined using tomography images. The septums were divided into three groups according to the severity of deviation. The cross-sectional area of the contralateral side divided by the cross-sectional area of the deviation was calculated and described as the interturbinate ratio. When bilateral CB was found, the pneumatization of the CB was more prominent on the contralateral side than on the deviation side in both the paediatric and the adult groups. However, we found that the interturbinate ratios were not statistically different between the paediatric and adult groups. Also, the interturbinate ratios were independent degrees of deviation in children and adults. The frequency of CB was low in the adult group compared with the paediatric group. Interturbinate ratios were not statistically different between paediatric and adult groups and were independent of the severity of deviation. These findings suggest that the pneumatization process is not compensatory.

On-line adaptive clustering for process monitoring and fault detection

An adaptive clustering procedure specifically designed for process monitoring, fault detection and isolation is presented in this paper. The key feature of the proposed procedure can be identified as its underlying capability to detect novelties in the system’s mode of operation and, thus, to identify previously unseen functioning modes of the process. Once a novelty is detected, relevant informations are used to enrich the knowledge-base of the algorithm and as a result the proposed clustering procedure evolves and learns the new features of the monitored process in accordance with the available process data. The suggested clustering procedure is theoretically illustrated and its effectiveness has been investigated experimentally. Particularly, the on-line implementation of the algorithm and its integration with a fault detection expert system have been considered by making reference to a pneumatic process.

Nebulizing conditions of pneumatic electrospray ionization significantly influence electrolyte effects on compound measurement

Composition of mobile phase can greatly influence the success of electrospray ionization (ESI)-interfaced liquid chromatography-mass spectrometry analysis. To investigate the relationship between formic-acid-based modification of mobile phase and ESI nebulizing conditions, an API 4000 ESI source and a TSQ Quantum one were compared under the same chromatographic conditions. Ginkgo terpene lactones and flavonols were measured in plasma, which involved using ascorbic acid to circumvent cross-interference between the analytes. ESI responses to using formic acid included changes in signal intensity, matrix effect, and upper limit of quantification. Significant disparities in the responses were observed between the two ESI sources, suggesting that the use of electrolyte modifier in liquid chromatography mobile phase and the pneumatic nebulization for ESI should be properly balanced to accomplish optimal ESI-based analysis. The distribution of unpaired ions toward the surface of the initial droplet was assumed to be an important step in the pneumatic ESI process. When using the electrolyte in mobile phase, a too fast droplet reduction by rapid-heating-assisted pneumatic nebulization could negatively decrease the time available for the unpaired ions to migrate from droplet interior to its surface. Ascorbic acid was identified as a major interfering substance for the bioanalytical assay; the interference mechanism might be associated with hindering the unpaired analyte ions from distributing toward the droplet surface rather than outcompeting the analyte ions for the limited excess charge on droplets surface. The current work extends the knowledge base of pneumatic ESI, which has implication for optimal use of the ESI-interfaced liquid chromatography-mass spectrometry technique.

Study on Novel Automatic Steel Bundling Machine Pneumatic Control System

This paper introduces a new type of automatic steel bundling machine for bundling process, which includes a pneumatic action process, mainly do some researches on the pneumatic control system. The system chooses PLC as the core control component, puts forward the hardware of control system and control flow. Eventually we have been designed the control program.

Modeling of pneumatic melt spinning processes

AbstractComputer simulation of the pneumatic processes of fiber formation from the polymer melts is discussed. The dynamics of air‐drawing of thin polymer streams in supersonic air jets formed in the Laval nozzle is presented versus the melt blowing process. In the Laval nozzle process, the air flow takes place with high Reynolds number and the k–ω model is used which considers kinetic energy of the air flow and the specific dissipation rate of the kinetic energy. For melt blowing, the air fields are simulated with the use of the k–ε turbulent model. The air velocity, temperature, and pressure distributions along the centerline of the air jets are considered in the modeling of both pneumatic processes. The air fields are predetermined at the absence of the polymer streams for several air compression values in the Laval nozzle inlet and several initial air velocities in the melt blowing process. Each polymer stream in a usual configuration of a single row of the filaments in the process is considered as non‐interacting aerodynamically with other streams, and the air jet is assumed to be undisturbed by the polymer streams. Air‐drawing of the polymer filaments is simulated as controlled by the distribution of air velocity, temperature, and pressure on the air jet centerline with the use of a stationary model of melt spinning in a single‐, thin‐filament approximation. Effects of non‐linear viscoelasticity of the polymer melt subjected to fast uniaxial elongation are accounted for in the modeling. Strong influence of the air jet velocity, the melt viscosity which controls response of the polymer melt on the air‐drawing forces, and the die‐to‐collector distance has been predicted. Influence of initial air temperature, geometry of the air die, initial velocity and temperature of the melt, extrusion orifice diameter can be also predicted from the model. The example computations concern air‐drawing of isotactic polypropylene with the use of the Laval nozzle are compared with the predictions for the melt blowing process. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Designing superplastic forming process of a developmental AA5456 using pneumatic bulge test experiments and FE-simulation

Relatively low tooling costs, high design complexity coupled with low forming speeds make the superplastic sheet metal forming process attractive, especially for smaller lot sizes. Due to the relatively small lot size, the effort and budget for designing superplastic forming processes is usually limited (Kappes and Liewald in J Mater Sci Eng B1:472–478, 2011). For this reason the tool design and corresponding pressure profiles in superplastic forming processes are often based on trial and error (Franchitti et al. in 11th international Esaform conference on material forming, 2008; Barnes in J Mater Eng Perform 4:440–454, 2007). Consequently a process chain should be established to design superplastic forming processes accurately and efficiently. This paper deals with the process chain to form an aluminium part superplastically. At the beginning of the process chain, there is a new, developmental aluminium alloy sheet (AA5456, s0 = 1.6 mm) designed for superplastic forming supplied by Hydro Aluminium Rolled Products GmbH. The relevant material parameters of this sheet are then determined via pneumatic bulge testing with and without in situ measurement of strains. Using these experimentally determined parameters superplastic forming process can be simulated by FE modelling (PAM-STAMP 2G). Due to in situ measurement of strains during pneumatic bulging, the comparison of experiment and FE-simulation results over the whole pneumatic bulging process could be done. This comparison shows good correlation for the observed conditions. Furthermore a cylindrical cup was simulated, evaluated via determined isobar Superplastic Forming Limit Curve (at fracture) and finally formed by pneumatic bulging. Material characterisation of the bottom of this cup showed that excessive cavitation was observed as a result of the iron-silicon particles. Superplastic forming of a bracket usually formed out of AA5083 was also simulated using material parameters of AA5456. The simulation was able to show that this part is not able to be manufactured out of AA5456 under these forming conditions, which was confirmed by forming trials performed at ALU-SPF AG.

Numerical Simulation and Thermal Factorial Analysis of Pneumatic Drying on Straw Fuel

Based on the mechanism of mass and heat transfer of the particles and air in drying tube, the mathematics model of pneumatic drying process was established which referred to straw fuel in straight horizontal tube, and the equations were solved by Runge-Kutta integration method. Then, by analyzing the thermal factors of gas flow drying，the most important factor in gas flow drying on straw fuel was summed up which was the mass of hot air. The method of orthogonal experimental design was used to analyze the whole process of gas flow drying, and primary and secondary roles led to the conclusion, which were the mass of hot air first , the equivalent diameter of the fuel granule and the temperature of hot air.

Fractal Theory’s Investigation in Pneumatic Flocculation Process

Coagulation-sedimentation test at different inflatable combinations, and using microscope to observe the morphological characteristics of flocs. This paper also measured the flocs’ fractal dimension. And analyzed the relationships between fractal dimension and floc characteristics, Coagulation effect

The Application of Mathematical Model and Numerical Simulation in the Pneumatic Drying of the Straw

According to the analysis of the characteristics of the biomass straw in its pneumatic drying process, some reasonable assumptions concerning the pneumatic drying are made and the mathematical model of heat and mass transfer in the biomass straw’s pneumatic drying process in the horizontal straight tube. Besides, the numerical method is adopted to solve the model and the analog simulation concerning the moisture content, temperature and the speed changes of the material and the air is conducted. Meanwhile influence of the gas-solid ratio and the air flow’s initial temperature on the drying effect is the analog simulated and the reason for this phenomenon is also analyzed.

Controversies in selection of block bone grafting and the elevation of the maxillary sinus floor with particulated bone in the reconstruction of posterior–superior alveolar reabsorbed

The process of bone resorption and pneumatization of the maxillary sinus are phenomena related to tooth loss in the posterior–superior area, which at present increase the difficulty mentioned rehabilitation area. However, there are treatment options for this condition as are, among others, the elevation of the maxillary sinus floor with particulated bone indicated for small bone defects exposed to low mechanical stress, and alveolar ridge augmentation with block grafts to reconstruct large areas of bone loss due to its stability.

Fast DNA hybridization on a microfluidic mixing device based on pneumatic driving

A novel fluid mixing strategy was developed which significantly enhanced the efficiency of DNA hybridization. A pneumatic micro-mixing device consisting of two pneumatic chambers and an underneath DNA microarray chamber was built up. The fluid in the array chamber was pneumatically pumped alternately by the two pneumatic chambers. The chaotic oscillatory flow caused by the pumping greatly intensified the fluidic mixing. A homogeneous distribution of the tracer dye solution in the microarray chamber was observed after 2s mixing with a pumping frequency of 24Hz. Microarray DNA hybridization was substantially accelerated using this device, and the fluorescence intensity showed a plateau after oscillating 30s at room temperature. The corresponding signal level of the dynamic hybridization was 12.5-fold higher than that of the static hybridization performed at 42°C. A signal-to-noise ratio of 117 was achieved and the nonspecific adsorption of the targets to the sample array was minimized, which might be attributed to the strong shearing force generated during the pneumatic mixing process.

Particles Mass Flow Rate and Concentration Measurement using Electrostatic Sensor

Abstract In many industries where flow parameters measurement is essential to control manufacturing process, the use of a reliable, cost effective and high accuracy instrument is an important issue. Appropriate measurement method and design leads to improvement of pneumatic conveyors operation and process efficiency. This paper present an instrumentation design based on passive charge detection using a single electrostatic sensor. Two different sensor electrodes are applied to show the flexibility of electrostatic sensor application. A time domain signal processing algorithm is developed to measurement of mass flow rate and concentration profile from acquired electrical charge signal. The findings is led to a low cost and high accuracy design, the experimental test results of the design shows less than ±5% error between measured parameters and reference reading acquired from the manual weighing.

Volume and Surface of the Mastoid Cell System in Otitis Media With Effusion in Children

To characterize the pneumatization of the temporal bone in age-matched healthy children and in children with otitis media with effusion (OME). Prospective case-control study. Tertiary hospital center. This study included 40 healthy children and 56 children with OME, with age ranging from 2 to 18 years. Mastoid volume and surface determination by 3-dimensional reconstruction of axial temporal bone computed tomographic images. Mastoid volume and surface area comparison of healthy children and children with OME. The mastoid cell system (MCS) grows continuously up to the age of 18 years, with different intensities. The mean ± SD MCS volume and surface of children with OME are significantly lower (2.82 ± 1.51 ml and 40.45 ± 18.14 cm, respectively) than those of healthy children (10.05 ± 5.3 ml and 84.47 ± 37.95 cm, respectively). The mastoid volume and surface area of the left and right ears correlate well in healthy children. In children with bilateral OME, the ipsilateral and contralateral ears can be largely different. The ratio of surface and volume is constant in age groups. In children with OME, the functional volume of MCS acting as a pressure buffer and the surface area serving for gas exchange are small. In case of OME, 1 ear could be more seriously affected by the disease. Otitis media with effusion presumably has a negative effect on the mastoid pneumatization process. The surface-to-volume ratio is constant through chronological age and is a good indicator of a normal middle ear function.

Optical and electrical properties of lithium doped nickel oxide films deposited by spray pyrolysis onto alumina substrates

Non-doped and lithium doped nickel oxide crystalline films have been prepared onto quartz and crystalline alumina substrates at high substrate temperature (600 °C) by the pneumatic spray pyrolysis process using nickel and lithium acetates as source materials. The structure of all the deposited films was the crystalline cubic phase related to NiO, although this crystalline structure was a little bit stressed for the films with higher lithium concentration. The grain size had values between 60 and 70 nm, almost independently of doping concentration. The non-doped and lithium doped films have an energy band gap of the order of 3.6 eV. Hot point probe results show that all deposited films have a p-type semiconductor behavior. From current–voltage measurements it was observed that the electrical resistivity decreases as the lithium concentration increases, indicating that the doping action of lithium is carried out. The electrical resistivity changed from 10 6 Ω cm for the non-doped films up to 10 2 Ω cm for the films prepared with the highest doping concentration.

Three-dimensional modelling of pneumatic drying process

Steady-state three-dimensional calculations of heat and mass transfer in vertical pneumatic dryer were performed. The theoretical model of the drying process is based on two-phase Eulerian–Lagrangian approach for gas-particles flow and incorporates advanced drying kinetics for wet particles. The model was utilized for simulation of the drying process of wet PVC and silica particles in a large-scale vertical pneumatic dryer. The influence of wall thermal boundary conditions was investigated by assuming either known value of the wall temperature or adiabatic flow in the dryer. Analyzing the predicted particle drying kinetics, an uneven product quality was predicted due to non-uniform drying conditions in the central and peripheral zones of the pneumatic dryer. Moreover, for the case of non-insulated chamber walls such quality unevenness was estimated to be substantially greater than for the case with thermally insulated drying chamber. The examination of the predicted temperature profiles within the silica and PVC wet particles showed that the latter is subjected to higher temperature gradients potentially resulting in the greater rate of thermally-degraded final product.