Pneumatic Injector Research Articles

Needle-free electronically controlled jet injection with corticosteroids in recalcitrant keloid scars: a retrospective study and patient survey

First-line treatment of keloids consists of intralesional needle injections with corticosteroids, but generally entails multiple painful sessions, resulting in variable clinical outcomes. Novel needle-free jet injectors may facilitate more effective and patient-friendly dermal drug delivery. Here, we evaluated the effectiveness, tolerability and patient satisfaction of intralesional triamcinolone-acetonide (TCA) treatment in recalcitrant keloids using an electronically controlled pneumatic injector (EPI). A retrospective study was conducted in recalcitrant keloid patients with a history of severe pain during needle injections who received three sessions of EPI + TCA. Outcome measures included Patient and Observer Scar Assessment Scale (POSAS), Global Aesthetic Improvement Scale (GAIS), treatment-related pain (NRS), adverse effects, and patient satisfaction (survey). Ten patients with in total 283 keloids were included. The POSAS score significantly improved at follow-up and GAIS was reported as ‘(very) improved’ for all patients. EPI + TCA was well-tolerated with a significantly lower NRS pain score compared to needle + TCA (pilot treatment). Only minor adverse effects occurred, and 90% of patients preferred EPI over needle treatment. EPI + TCA is an effective and tolerable treatment for patients with recalcitrant keloids. The minimal treatment-related pain and high patient satisfaction makes it a promising treatment for patients with needle-phobia and/or severe pain during needle injections.

Mechanism and clinical applications of needle-free injectors in dermatology: Literature review.

Needle-free jet injectors are devices that deliver drugs using a high-speed jet without a needle. Recent studies have significantly increased our understanding of the mechanisms of needle-free jet injectors, and technical advancements have broadened the scope of application of the device. We aimed to provide an up-to-date review of previous literature regarding the mechanism of action and clinical applications of needle-free jet injectors in dermatology field. We conducted a PUBMED search for studies on needle-free jet injectors using the following parameters: "Pneumatic injector" OR "needleless injector" OR "needle-free injector" OR "jet injector." Among 191 results, 72 articles focusing on their mechanisms of action, cutaneous delivery patterns, and clinical applications in dermatology were selected for review. Significant clinical evidence has been published confirming the potential of needle-free jet injectors in treating various dermatologic conditions. In particular, these devices have the potential to be used in various skin remodeling treatment, especially in skin rejuvenation procedures by injecting various esthetic materials. As proven by accumulated experience, the applications of NFJIs are not restricted to vaccine or insulin delivery in dermatology field. However, this literature review shows that until now, there are no clinical guidelines that standardize the optimal parameters when using NFJIs on various clinical settings. Therefore, further studies should be performed in order to investigate the full potential of these devices in dermatology, to ensure safe and effective outcomes in clinical practice.

Models of Locomotive Traction Drives for the Improvement of Sand Feeding System

In this research, we calculated the key characteristics and parameters of the pneumatic injector using the set input and output gas flow values. We simulated the ejection of excessive air from the ambient to increase the flow rate of the air-and-sand mixture from the outlet chute of the sand feeding system of a locomotive using the CFD package of the FlowSimulation extension of the SolidWorks solid object design environment. We achieved the reduction of the compressed air consumption as compared to the standard locomotive sand-feeding systems.

A combined experimental and computational study of flow-blurring atomization in a twin-fluid atomizer

A twin-fluid pneumatic injector system with coaxial liquid and air streams mixed slightly upstream of the outlet, is studied in a cross-flow arrangement to understand its working principle. The gap between the orifice and the liquid tube, where the air and liquid cross-flow occurs, is known to determine the modes of working of the atomizer for the given operating flow rates of air and liquid. The two distinct modes, namely the flow focusing (FF) and flow blurring (FB) are observed in the present study, and the transition from FF to FB mode is explored using optical visualization. The characteristics of the internal two-phase flow mixing that occurs due to backflow recirculation in FB mode are also investigated by performing large eddy simulation (LES) using the volume of fluid (VoF) approach. The results of the numerical simulation are validated with experimental observations for the length of backflow recirculation observed in the liquid tube. The present study demonstrates the development of multiple microjets, which explains experimental observations of the lack of core jet and the almost uniform distribution of radial Sauter mean diameter (SMD) reported in the literature. The high-resolution backlit image of a scaled-up transparent injector with a 6 mm orifice diameter validates the numerical results that describe the internal two-phase flow.

Manufacture of hybrid pieces using recycled R-PET, polypropylene PP and cocoa pod husks ash CPHA, by pneumatic injection controlled with LabVIEW Software and Arduino Hardware

The research consists of the design and automation of a pneumatic injector, applying LabVIEW software through an integrated Arduino hardware module, programming through an interface, the pressure that guarantees the geometric quality in the models obtained. The final result shows a piece designed in mass fraction with 40% polypropylene resin (PP), 40% recycled polyethylene terephthalate in the form of scales (R-PET) and 20% from cocoa pod husks ash (CPHA). Likewise, the platform allows to define and control the conditions of generation of the product, defining a pattern according to the type and the mass proportion between the resin of PP, R-PET and CPHA. In addition, the design of the mechanical and thermal elements, consisting of the piston and the system of clamp-type resistors, the pneumatic injection means and the raw material feed gate, improve the efficiency and effectiveness of the equipment.

The Formation of Multiple MiliaInduced by Pneumatic Injector Therapy for Scar Remodeling

The Formation of Multiple MiliaInduced by Pneumatic Injector Therapy for Scar Remodeling

A technique for numerical modeling of liquid film disintegration in the pneumatic injector of aircraft engines

A technique for calculating the two-phase flows in the pneumatic injector of the aircraft engine is developed based on solving the model problem, namely, on verification of the two-phase flow model by means of solving the problem of liquid column disintegration under the effect of an incident airflow. We determine the turbulence models that satisfactorily describe the biphase flow processes.

Cleaning System with Large Consumption of Gas Emissions

High-temperature system of cleaning harmful emissions is proposed by tests high power turbine engines. It includes a new nozzle design, installed on the exhaust pipe containing a sprayers for spraying a mixture of water with ozone. Maximum decrease of temperature of gases emissions is achieved by full evaporation of the liquid drops within pipe nozzle. Provides a methodology for calculating diameter channels of pneumatic injectors by hydraulic spraying to drops, which provide their complete evaporation. To demonstrate with an example of calculating the duct diameter, the diameter of the droplets, the evaporation time within a multipurpose exhaust nozzle stand testing of gas turbine engines with a capacity of 40 MW with consumption of gas emissions 365 m 3 /c, and temperature 560 °C.

A novel pneumatic micropipette aspiration method using a balance pressure model

This paper presents a novel micropipette aspiration (MA) method based on a common pneumatic micro-injection system. This method is the first to quantify the influence of capillary effect on aspiration pressure using a balance pressure model, and in return, uses the capillary effect to quantify the aspiration pressure. Subsequently, the seal between the cell and the micropipette is detected to judge and exclude the ineffective MA attempts. The rationality of the balance pressure model is validated by the designed micropipette-filling experiments. Through applied to elasticity-determination of the cells with different sizes, the feasibility and versatility of this MA method are proved. With abilities to quantify aspiration pressures and detect the seam between the cell and the micropipette, our method is expected to advance the application of the commercial pneumatic injector in the MA of cells. Moreover, with the quantified volume of the liquid entering into the micropipette during MA process, our method also has a potential applicability to the study of the permeability of the cell membrane in the future.

Clinical efficiency and safety of piezo-ICSI with pneumatic injector

Clinical efficiency and safety of piezo-ICSI with pneumatic injector

Reacting shock bubble interaction

In this work, experimental results are presented for the first time on the shock-initiated combustion of a spherical density inhomogeneity. A converging lens geometry, in which a heavy bubble free-falls in a lighter fluid, is used to focus a planar shock wave resulting in the ignition of a mixture of H 2, O 2 and Xe (55%, 30% and 15%, respectively) in N 2. The experiments are performed at the Wisconsin Shock Tube Laboratory in a 9 m vertical shock tube with a 25.4 cm square cross-section. A pneumatic injector is used to generate a 4 cm diameter soap film bubble filled with the combustible mixture. The injector retracts flush into the side of the tube releasing the bubble into a state of free-fall. The initial conditions are captured with two high speed CMOS cameras orientated perpendicular to one another. Simultaneous Mie scattering and chemiluminescence diagnostics are used to image the post-shock bubble morphology and combustion, respectively. The ignition delay times are measured for several incident shock strengths (1.3 < M < 2.9, where M is the Mach number) and range between 5 μs and 400 μs. The ignition delay times are used in combination with 1D gas dynamics to estimate the effect of shock-focusing. It is observed that two limiting cases emerge, with the combustion characteristics depending heavily on the incident shock strength. A comparison to non-combusting mixtures is made by matching the density of the bubble mixture without the fuel (49% Xe, 51% O 2).

Optical diagnostics of gas-droplet flows

A gas-droplet flow generated by a pneumatic injector with internal mixing is studied by optical methods. The fractional composition and the spatial distribution of liquid droplets for different fractions are measured, as well as the mean velocity field.

Characteristic features of the process of mixture formation upon fuel injection into a high-temperature air flow

Physical models of the processes of interphase heat and mass transfer and computational techniques based on them are suggested. The problem of the interaction of fuel droplets with a high-temperature air flow is solved numerically. It is shown that injection of a fuel by a spray atomizer may cause a substantial change in the gas temperature. With pneumatic spraying of a fuel by a cold air jet the influence of interphase exchange on the characteristics of the main flow is insignificant. Upon injection of a hot spraying air the influence of fuel injection on the formation of temperature fields is more appreciable. However, here the gas is cooled less than in the case of spraying by a jet. Introduction. Combustion of a fuel in the combustion chambers of a gas-turbine engine and a gas-turbine plant is closely connected with the processes of mixing (1). Investigations of these processes carried out by both ex- perimental and computational methods (1-3) have recently become especially crucial because of the necessity of solv- ing ecological problems. One of the most pressing problems at present is account for the influence of droplets on an air flow. In some of the regimes of chamber operation this may lead to a substantial, almost twofold, change in the long range of a fuel spray and, consequently, to corresponding changes in the distributions of the concentrations of fuel phases. In this work we set out to calculate the fields of air velocity and temperature as well as of the distribution of a liquid fuel in a module combustion chamber with account for the processes of heating and evaporation of droplets in those regimes typical of combustion chambers in which there is a substantial interphase exchange. The influence of interphase heat exchange on mixing in the working volume of the module was considered earlier in (4). It was shown that the computational technique describes well the experimental data on the configuration of the fuel spray. In the present work, the technique is supplemented with account for mass exchange between liquid and gas phases. It is clear that when a "cold" fuel is supplied into a "hot" air flow, the droplets are heated and the air sur- rounding them is cooled. It is evident that at small flow rates of the fuel this cooling can be neglected. The aim of this work is to answer two questions: how much the air flow is cooled in the range of parameters typical of real com- bustion chambers, and how far the region of flow cooling extends. Moreover, the dependence of the flow charac- teristics on the means of fuel spraying (jetty or pneumatic) and also on the spraying air temperature is investigated. Statement of the Problem. The model selected for investigation is a straight channel of rectangular cross sec- tion 50 × 30 mm and 150 mm long into which air is supplied at a velocity U0 and temperature T0. Injection of a fuel with a temperature Tf into the channel at a velocity Vf is made through a hole in the upper wall of the channel with the aid of an injector installed along the normal to the longitudinal axis of the channel halfway between the side walls. In modeling the pneumatic injector it is considered that, coaxially with the fuel supply, the spraying air is fed at a velocity U1 and temperature T1 into the channel through a rectangular hole of size 4.5 × 3.75 mm. In modeling a jetty injector, we assume that the spraying air is absent. Calculations were carried out for the velocity and tempera- ture of the main air flow U0 = 20 m ⁄ sec and T0 = 900 K, Vf = 8 m/sec, Tf = 300 K. The gas pressure at the channel inlet was equal to 100 kPa. The variable parameters of the calculation were the velocity and temperature of the spray- ing air: U1 = 0-20 m ⁄ sec and T1 = 300-900 K, as well as the summed coefficient of air excess through the module α = 1.35-5.4. The values of the regime parameters are presented in Table 1. Regime 1 corresponds to jet spraying of

A pneumatic injector of hydrogen pellets for the LHD stellarator

A pneumatic injector for periodic injection of fuel pellets into plasma of a thermonuclear facility in a continuous mode for an infinitely long time is described. The continuous injection is ensured by a screw extruder and two cryorefrigerators that allow extrusion of solid hydrogen rods with diameters of 2 and 2.5 mm at a speed of up to 40 mm/s in a steady-state mode. A cylindrical cutter and a valve with compressed hydrogen form solid-hydrogen pellets with diameters of 2 and 2.5 mm from the rod and inject them into plasma at a frequency of up the 11 Hz and a speed of 150–550 m/s. The reliability of the injector’s operation is 99%.

Cryogenic pellets with controlled length for pellet ablation studies

A prototype of a pneumatic injector of hydrogen cryogenic pellets with controlled length is under development at Kyushu University. The major element of the prototype is a remote cylindrical freezing cavity with controllable length which allows the length of a frozen hydrogen pellet formed in situ to be adjusted precisely and continuously from sub-millimeter to a few millimeters. The design and operation of the prototype are described. The initial results of experimental adjustment of the pellet length are also reported. The length of 1.4 mm diameter hydrogen ice pellets has been varied continuously from 0.5 to 3.0 mm at a temperature range of 6–9 K. The prototype has launched single solid pellet with controlled length through room temperature helium gas at a pressure of 0.5–2 MPa.

A pneumatic injector of deuterium pellets for the TORE-SUPRA tokamak

A pneumatic injector for periodic injection of fuel—solid-deuterium pellets—into the plasma of the TORE-SUPRA tokamak in a steady-state mode is described. Injection of deuterium pellets with an unlimited duration is ensured by a screw extruder in which gaseous deuterium is frozen and squeezed outwards in the form of a rod with a rectangular cross section. A cutter installed on the injector’s barrel cuts a cylinder with a diameter of 2 mm and a length of 1.0–3.5 mm out from this rod. The movement of the cutter is controlled by a pulsed electromagnetic drive at a pulse repetition rate of 10 Hz. In the injector’s barrel, a compressed gas accelerates a deuterium pellet to a velocity of 100–650 m/s.

Pellet injectors for steady state plasma fuelling

Successful steady state operation of a fusion reactor should be supported by repetitive pellet injection of solidified hydrogen isotopes in order to produce high performance plasmas. This paper presents pneumatic pellet injectors and its implementation for long discharge on the LHD and TORE SUPRA, and a new centrifuge pellet injector test results. All injectors are fitted with screw extruders well suited for steady state operation.

Heat and Mass Exchange During Fluidized-Bed Coating of Tablets

In the process of coating tablets in a fluidized-bed reactor, the coating material (typically an aqueous solution) supplied via a pneumatic injector distributes homogeneously over the surface of tablets owing to their intensive stirring. The shell grows in a cyclic regime, whereby a thin liquid film formed on tablets occurring in the injector torch zone is dried in the intermediate layer and then the cycle is repeated. Thus, the shell deposition and drying processes are combined, This process is usually described in terms of the heat and mass balance equations. However, use of these relations frequently leads to errors in determination of the process parameters, violation of the system stability, and the related decrease in the efficiency of apparatuses. The results of preliminary investigations showed that one of the main factors determining stability of the coating process is the kinetics of heat and mass exchange between tablets in the fluidized bed and a hot heat-transfer agent. The kinetics of the external heat and mass exchange is determined by changes in the density of water vapor and the temperature of the heat-transfer agent at the tablet surface. The density gradient creates a vapor flow directed from the surface to the core of the heat-transfer agent flow, while the temperature gradient provides for the heat supply to the tablet surface. A strict theoretical analysis of the external heat and mass exchange is based on the system of differential equations describing the transfer of momentum, energy, mass, and heat. The mutual influence of these process is taken into account by introducing the corresponding kinetic coefficients [1]. However, an analytical solution of the external heat and mass exchange problem with allowance for the mutual influence of various factors is extremely difficult to obtain because of difficulties encountered in the calculation of these kinetic coefficients [2]. For this reason, the analysis of heat and mass exchange processes requires using experimental data. In the course of coating, a tablet initially exhibits cooling because the liquid is evaporated at the expense of accumulated heat. Then, the evaporation of liquid from the surface proceeds at a constant temperature at the expense of heat supplied with the heat-transfer agent, after which the tablet is heated again. The molecules of water occurring on the tablet surface diffuse both to the stream of heat-transfer agent and, partly, inward the tablet. However, the latter diffusion proceeds at a significantly lower rate and can be ignored in comparison to the former process. Taking into account that the thickness of the liquid film formed in every wetting cycle is relatively small, we can assume that the rate of heat and mass exchange is determined entirely by the outdiffusion. Then, the process under consideration is described by the following equation: mc

The fluidized bed combustion of a heavy liquid fuel

Fluidized bed combustion as a flexible facility has been applied to burn liquid fuel. In the present work, a heavy oil (mazut) has been successfully dispersed and efficiently burnt with in situ desulfurization in a fluidized bed combustor. An atmospheric bubbling fluidized bed combustor of 300-mm inner diameter has been used. The liquid fuel has been injected into the bed using a multi-nozzle pneumatic injector. Measurements have been carried out under steady state operation. Results of experiments indicated that the in-bed combustion of fuel has been enhanced with increasing bed temperature, bed height, excess air and mass flow rate of dispersing air. Fortunately, the later trends improved both combustion efficiency and sulfur retention. High combustion efficiency has been obtained up to 99.7%. Sulfur retention up to 90% has been achieved by adding limestone particles. On the other hand, NO x has been slightly promoted with increasing the mentioned operating parameters, however, the obtained NO x emission was usually <130 ppm.

Status of the Russian pellet injector R&D program for plasma fuelling

Basic trends of research within the Russian pellet injector R&D program for 1999–2001 are discussed. The attention is focused on injectors with a screw extruder and those with a porous generator capable of injecting pellets in a repetitive continuous steady state mode. Over 12 000 deuterium pellets of 2 mm diameter were produced and accelerated to 200 m/s at a rate of 10 Hz with a reliability over 99% by a pneumatic injector equipped with a screw extruder. Over 2000 hydrogen pellets of 2.4 mm diameter and 4 mm length were accelerated to 1 km/s at a rate of 0.3–0.8 Hz by a pneumatic injector equipped with a porous generator with no moving parts. The injector designs and experimental results are presented and a concept of a new centrifuge pellet injector is discussed.