Influence Of Injection Parameters Research Articles

Rose Bengal Labeled Bovine Serum Albumin for Protein Transport Imaging in Subcutaneous Tissues Using Computed Tomography and Fluorescence Microscopy.

Subcutaneous (SC) injection of protein-based therapeutics is a convenient and clinically established drug delivery method. However, progress is needed to increase the bioavailability. Transport of low molecular weight (Mw) biotherapeutics such as insulin and small molecule contrast agents such as lipiodol has been studied using X-ray computed tomography (CT). This analysis, however, does not translate to the investigation of higher Mw therapeutics, such as monoclonal antibodies (mAbs), due to differences in molecular and formulation properties. In this study, an iodinated fluorescein analog rose bengal (RB) was used as a radiopaque and fluorescent label to track the distribution of bovine serum albumin (BSA) compared against unconjugated RB and sodium iodide (NaI) via CT and confocal microscopy following injection into ex vivo porcine SC tissue. Importantly, the high concentration BSA-RB exhibited viscosities more like that of viscous biologics than the small molecule contrast agents, suggesting that the labeled protein may serve as a more suitable formulation for the investigation of injection plumes. Three-dimensional (3D) renderings of the injection plumes showed that the BSA-RB distribution was markedly different from unconjugated RB and NaI, indicating the need for direct visualization of large protein therapeutics using conjugated tags rather than using small molecule tracers. Whereas this proof-of-concept study shows the novel use of RB as a label for tracking BSA distribution, our experimental approach may be applied to high Mw biologics, including mAbs. These studies could provide crucial information about diffusion in SC tissue and the influence of injection parameters on distribution, transport, and downstream bioavailability.

Factors influencing the mobility control ability of diutan gum‐enhanced foam in porous media

AbstractDiutan gum (DG) is an anionic polysaccharide produced by Sphingomonas sp. ATCC 53159. The DG‐enhanced foam (DGEF) formed by the DG and foam has great application potential in enhanced oil recovery. In this research, the influence of injection parameters on DGEF was studied by conducting orthogonal experiment, with residual resistance coefficient (Rff) as the main evaluation index. The micro‐state of the foam was observed using an etching model and scanning electron microscope. The mechanism of different factors on the mobility control ability of the foam was discussed based on the apparent viscosity and surfactant depletion. The results show that the Rff of foam is correlated with the apparent viscosity, and the foam with high apparent viscosity had a good flow control ability. The calculation of the surfactant depletion shows that the bubble stability decreased significantly when the concentration of Sodium alpha‐olefin sulfonate (AOS) cannot meet the minimum stabilization concentration, thus weakening the mobility control ability. Based on the study of crude oils, the presence of oil phase will seriously weaken the mobility control ability of DGEF, but the effect of oil with higher content of resin and asphaltene will be relatively weak.

Diffusion Model of Cement Slurry in Porous Media Considering Porosity Variation and Percolation Effect

The porosity of porous media is a key factor affecting cement slurry diffusion. In this paper, a theoretical model of cement slurry diffusion in porous media considering the variation of porosity is proposed. The model is validated through comparison with the experimental results in the literature. The influence of injection parameters (i.e., the water–cement ratio and the pore fractal dimension) on the porosity and strength of porous media is analyzed. The results indicate that: under the same pore fractal dimension, the porosity of the specimen increases gradually with the increase in diffusion distance, and the rate increases rapidly in the later stage. However, when the fractal dimension of porosity increases to 2.1, the porosity of the consolidated body after grouting does not change with the diffusion distance. The water–cement ratio also affects the porosity of the sample. At a distance below 1.0 m, the sample porosity is larger at a larger water–cement ratio of 1.5. When the distance is more than 1.0 m, the smaller the porosity decreases with increasing water–cement ratios. With the increase in distance, the compressive strength of the specimen first decreases slowly, and then rapidly from 90 kPa to 0 kPa. This is further verified by the pore variation law obtained by SEM. The model is applied to selecting grouting parameter design in road maintenance. The pavement deflection after grouting is effectively reduced, verifying the theoretical model’s applicability.

Experimental investigation of the anchoring effect of aluminum/amorphous-plastics joints fabricated by injection molded direct joining

Injection molded direct joining (IMDJ) is an efficient metal-plastic direct joining method. IMDJ injects melted plastic onto a pretreated metal surface and forms joints due to the plastic infiltration into surface structures. Unlike widely studied semicrystalline plastics, this study focused on the influence of injection parameters on the joining strength for two amorphous plastics. The anchoring effect was investigated by measuring the joining strength and the infiltration depth after joining. The results show that the interaction between packing pressure and injection speed obviously influenced the joining strength. Both high packing pressure and high injection speed were necessary for high joining strength. In addition, the results show that the joining strength positively correlated with the infiltration depth. Furthermore, a real-time plastic infiltration process was directly observed via mold visualization. A dynamic understanding of the infiltration was obtained. This paper contributes to a better understanding of the infiltration and the anchoring effect for amorphous plastics.

Numerical investigations on turbulent jet ignition with gasoline as an auxiliary fuel in rapid compression machines

ABSTRACT Lean burning as one of the low-temperature combustion strategies has the potential to reduce pollution emissions and improve fuel efficiency. However, highly diluted mixtures cause internal combustion engines to suffer from severe combustion instabilities. Turbulent jet ignition (TJI) technology is considered an effective way to solve these issues, but most previous work mainly considers the passive TJI systems fueled by gaseous fuel. In this work, an active TJI system with gasoline as an auxiliary fuel was investigated using three-dimensional computational fluid dynamics (CFD) simulations in rapid compression machines (RCM). High-pressure low-temperature operating conditions were established to mimic the combustion situation of supercharged spark-ignition engines. Different injection parameters for pre-chamber were considered, including injection timing, injection angle, and injection pulse width, and the influence of injection parameters on the evolution of turbulent jet flame in the main chamber with lean mixtures was investigated. The results show that the hedging effect between reverse squeezed flow and high-speed fuel spray during piston compression promotes gasoline spray atomization, evaporation, and mixing in the pre-chamber. The initial lambda of the pre-chamber plays a significant role in the jet exit velocity, while the initial lambda of the main chamber exhibits a greater impact on the jet propagation distance. Meanwhile, there are generally three stages for the entire combustion in the main chamber, including jet penetration, jet ignition, and spontaneous combustion. The present work can provide useful insights into the optimization and design of active TJI systems in realistic engines.

Development of hybrid pattern material for investment casting process: an experimental investigation on improvement in pattern characteristics

ABSTRACT In this work, a hybrid pattern material is introduced for investment casting process to enhance the properties/characteristics of the pattern. The hybrid pattern material is prepared by mixing coconut oil into conventional wax pattern material’s ingredients and named as coconut oil-based hybrid (COBH) pattern material. A comprehensive experimentation was performed to examine the influence of injection parameters viz. injection temperature (IT), injection flow rate (IFR), and die temperature (DT) on COBH pattern characteristics such as surface roughness (SR), average shrinkage (AS), and needle penetration (NP). Regression models were developed and statistically analyzed. Additionally, multi-response optimization (MRO) was carried out using the desirability technique for minimum SR, AS, and NP. The ANOVA results revealed that all input variables significantly influenced the characteristics of the COBH pattern. The optimal parametric settings of IT = 65°C, IFR = 3.5 lpm and DT = 35°C obtained by MRO provided the desired responses (i.e., minimum SR, AS, and NP). The developed COBH pattern ban be utilized for the development of good quality castings.

Influence of injection parameters on combustion, gaseous emissions and particle size distribution of a CRDI diesel engine operating with PODE/diesel blends

This study deals with the experimental research on combustion process, gaseous emissions characteristics and particle size distributions of a high pressure common-rail direct injection (CRDI) diesel engine operating with PODE/diesel blends at different injection pressures (80 MPa, 90 MPa and 100 MPa) and injection timings (0.5°CA ATDC, 2.5°CA ATDC and 4.5°CA ATDC). The testing fuels were neat diesel, PODE/diesel blends with PODE volume fractions of 10% and 20%, which were marked as P0, P10 and P20 respectively. The results show that the maximum combustion pressure and peak value of heat release rate increase with the increment of injection pressure while the combustion pressure decreases slightly with the delay of injection timing. The CO, HC and soot emissions of the blended fuels decrease obviously with the increase of injection pressure, while the NOx increases, in which the increasing extent of NOx by fueling P10 is smaller than those of P0 and P20 fuels. Even though CO, HC and soot of the three fuels increase with the delay of injection timing, the NOx emissions decrease and the gaseous emissions of P10 fuel are still less affected by injection timing. The peak values of particle number concentration curves of the blends decrease with higher injection pressure, among which the proportion of accumulation particles decreases and the proportion of nucleation particles increases. The particle number concentration increases with the delay of injection timing for each testing fuel, but the geometric mean diameter (GMD) of P10 particles is little affected by the injection timing. Also, the particle diameter corresponding to the peak concentration for each testing fuel decreases with the increase of injection pressure and the advance of injection timing.

Assessment on the consequences of injection strategies on combustion process and particle size distributions in Euro VI medium-duty diesel engine

Although there are already several works where the influence of injection parameters on exhaust emissions, and specifically on particulate matter emissions, in diesel engines has been evaluated, the diversity in the results that can be found in the literature indicates the need to carry out new experiments that can provide more information about the influence of these parameters on modern diesel engines. This study intends to be placed within this scientific framework, hence a parametric study was carried out based on the independent modification of the main injection timing and the injection pressure with respect to the nominal conditions of a new Euro VI direct injection diesel engine. Four steady-state operation points of the engine map were chosen: 25% load and 950 r/min, 50% load and 1500 r/min, 75% load and 2000 r/min and 100% load and 2200 r/min, where in each of these operation points, the variations of the injection parameters in the study on the combustion process and its consequent impact on the particle size distribution, including an analysis of the geometric mean diameter values, were evaluated. The results showed that the different injection strategies adopted, despite not significantly affecting the engine efficiency, did cause a significant impact on particle number emissions. At the low load operation, the size distribution showed a bimodal structure, and as the main injection timing was delayed and the injection pressure was decreased, the nucleation-mode particle concentration decreased, while the accumulation-mode particle concentration increased. In addition, at medium load, the nucleation-mode particle emission decreased considerably while the accumulation-mode particle emission increased, and this increase was much greater with the main injection timing delay and the injection pressure reduction. Similar behavior was observed at high load, but with a much more prominent pattern.

Investigations of injection parameters on combustion oscillation in a supersonic crossflow

The influence of injection parameters on combustion oscillation inside an ethylene-fueled scramjet combustor equipped with a cavity flameholder is experimentally investigated for Mach 5.5 flight conditions. Experiments focusing on the influence of the fuel equivalence ratio, the premixing distance, the injection angle, and the number of jets have been carried out. Under certain conditions, high-speed camera and schlieren images show that flame oscillation occurs between the fuel injectors and the leading edge of the cavity. It is also demonstrated that those factors mentioned above can significantly affect the flow-shock interaction which generates low flow speed region and the mixing status which correlates with combustion intensity closely. The strong interaction between combustion and the separated boundary layer downstream of the cavity forms a thermal throat inducing thermal chocking to cause flame flashback. The distributions of the flame front, flame propagation speeds and quasi-periodic oscillation frequencies obtained by the iso-luminosity contour method show distinct differences in different cases. The strong interactions of flow and shock, combustion and separated region can easily trigger flame flashback, and the flame front can be maintained around the injector for long time in cases of deeper penetration depth and longer premixing distance. A simplified combustion opening system model predicts that the flame under sensitive conditions may acquire an exponential amplification once thresholds of the thermal fluctuation are exceeded.

Influence of injection parameters on NOx emission from biodiesel powered diesel engine by Taguchi technique

ABSTRACT This paper studies the effect of injection parameters on reduction of nitrogen oxide (NOx) emission in a multicylinder diesel engine using Taguchi orthogonal array. To obtain good performance in experiments, we have employed L9 Taguchi array on mixed level fractional design. The engine is fuelled with corn oil methyl ester biodiesel. From the experiment validation, it is found that the urea concentration and the spray angle reduce the production of NOx in the diesel engine. However, it is found that the mixing length does not support the diminution of NOx emission effectively. Additional, ANOVA outcome also reveals that the urea flow rate, urea concentration and the spray angle plays an imperative role in the reduction of NOx emission. The values of the experiments are in accordance with the Taguchi technique.

Influence of Injection Parameters and Operating Conditions on Ignition and Combustion in Dual-Fuel Engines

Dual-fuel (DF) engines offer great fuel flexibility since they can either run on gaseous or liquid fuels. In the case of diesel pilot-ignited DF engines, the main source of energy is provided by gaseous fuel, whereas the diesel fuel acts only as an ignition source. Therefore, a proper auto-ignition of the pilot fuel is of utmost importance for combustion in DF engines. However, auto-ignition of the pilot fuel suffers from lower compression temperatures of Miller or Atkinson valve timings. These valve timings are applied to increase efficiency and lower nitrogen oxide (NOx) engine emissions. In order to improve the ignition, it is necessary to understand which parameters influence the ignition in DF engines. For this purpose, experiments were conducted and the influence of parameters, such as injection pressure, pilot fuel quantity, compression temperature, and air–fuel (A/F) equivalence ratio of the homogenous natural gas–air mixture were investigated. The experiments were performed on a periodically chargeable combustion cell using optical high-speed recordings and thermodynamic measurement techniques for pressure and temperature. The study reveals that the quality of the diesel pilot ignition in terms of short ignition delay and a high number of ignited sprays significantly depends on the injection parameters and operating conditions. In most cases, the pilot fuel suffers from too high dilution due to its small quantity and long ignition delays. This results in a small number of ignited sprays and consequently leads to longer combustion durations. Furthermore, the experiments confirm that the natural gas of the background mixture influences the auto-ignition of the diesel pilot oil.

The influence of injection parameters on the performance and emission characteristics of a DI diesel engine using biofuel-blended-pure diesel fuel

The transport sector is the most essential driver of growth and economic development, which is one of the biggest contributors to climate change, responsible for almost a quarter of the global carbon dioxide emissions. In this paper, the experiments were conducted for an injection timing of 21° with standard injection pressure of 220 bar at different proportions such as 20%, 40% and 60% of biodiesel blends with pure diesel fuel. Other parameters like injection pressure and mass flow rate are kept constant. The performance parameters for running the engine are 1500 rpm and a rated power of 4.4 kW. The performance test resulted in the increased BTE and reduction in the SFEC for B20 blend as compared to the other proportions. The emission characteristics show that the CO, UHC and NOx were decreased for B20 when compared with the other proportions.

Influence of injection parameters, ozone seeding and residual NO on a Gasoline Compression Ignition (GCI) engine at low load

The main objective of this work was to evaluate the potential of ozone to overcome the low load limitations of Direct-Injection Gasoline Compression Ignition (D-I GCI) engines. Experiments were performed in a single-cylinder diesel engine fuelled with directly-injected 95 RON gasoline at 2bar IMEP. Engine speed was set to 1500rpm. Intake pressure was set to 1bar in order to investigate typical low load operating conditions. Chemical computation revealed that the O atoms coming from the O3 molecules and responsible for promoting fuel autoignition exhibited a maximum concentration near 30° before TDC. Experiments showed that a narrow umbrella angle extends the early injections range up to -60 CAD, better matching with ozone decomposition. Injection timing can be employed to better exploit the oxidizing effect of ozone, which proved to be dependent on local conditions of temperature, equivalence ratio, and concentration of O atoms and of the residual NO trapped after each combustion cycle. Results showed that the impact of ozone is generally higher at early injection, but that interaction between O3 molecules and NO contained in the trapped gas can drastically reduce or even make the promoting effect of ozone ineffective. Finally, seeding the intake of the engine with ozone is shown to be an effective way to improve the autoignition propensity of high octane fuel and to overcome the low load limitation of D-I GCI engines.

Experimental analysis of the influence of urea injection upon NOx emissions in internal combustion engines fueled with biodiesels

The effect of urea injection on NOx emissions in a six-cylinder, four-stroke internal combustion engine fueled with B80 biodiesel has been experimentally investigated. The results reveal that urea injection leads to a reduction of NOx emissions of B80 biodiesel fuel. Moreover, the influence of injection parameters on NOx reductions has been studied. The findings show that increasing the injection temperature results in lower NOx emissions. Also urea mass flow rate increment leads to more NOx reduction. The same result has been obtained by an increase in spray angle. In addition, increasing the number of nozzles indicates more depletion in NOx emissions while a “three-nozzles spray system” has the most considerable effect on NOx reductions.

Investigation on microstructure and properties of foamed (wood fiber)/(recycled polypropylene) composites

AbstractMicrocellular foamed (wood fiber)‐reinforced recycled polypropylene composites (MFWPCs) were prepared by an injection molding process where azodicarbonamide was used as a chemical foaming agent. The influence of injection parameters (injection temperature, dwell pressure) on the microcellular structure (cell diameter and cell density) and the mechanical properties of the MFWPCs were investigated. The results indicated that when the melting temperature was 180°C and the dwell pressure was 12.5 MPa, a uniformly distributed microcellular structure of MFWPCs was obtained. Compared with solid wood plastic composites, the density of the MFWPCs decreased by 24.5%, and its impact strength of MFWPCs increased by 53%, because the propagation direction of the crack changed to the “skip” or “bifurcation” mechanism as a result of the microcellular structure, and the surrounding matrix of this structure made it easy to produce forced high‐elastic deformation. The toughening mechanism of the microcellular structure was analyzed. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers

Influence of injection parameters and mold materials on mechanical properties of ABS in plastic injection molding

This study optimized effect of injection parameters such as melt temperature, packing pressure, cooling time and injection pressure on the mechanical properties of Acrylonitrile–Butadiene–Styrene (ABS) moldings. Mold materials having two different thermal conductivities, 191 W/mK for aluminum 2000 series and 50 W/mK for AISI 1020 at 25 °C were selected to use in experimental studies. Taguchi's L 9(3 4) orthogonal array design was employed for the experimental plan. Mechanical properties of ABS specimens such as elasticity module, tensile strength and tensile strain at yield, tensile strain at break, flexural modules and izod impact strength (notched) were measured by using some test methods. Signal to noise ratio for mechanical properties of ABS using the Taguchi method was calculated and effect of the parameters on mechanical properties was determined using the analysis of variance. Linear mechanical models were also created by using regression analysis.

Influence of injection parameters on the transition from PCCI combustion to diffusion combustion in a small-bore HSDI diesel engine

In this paper, the influence of injection parameters on the transition from Premixed Charge Combustion Ignition (PCCI) combustion to conventional diesel combustion was investigated in an optically accessible High-Speed Direct-Injection (HSDI) diesel engine using multiple injection strategies. The heat release characteristics were analyzed using incylinder pressure for different operating conditions. The whole cycle combustion process was visualized with a high-speed video camera by simultaneously capturing the natural flame luminosity from both the bottom of the optical piston and the side window, showing the three dimensional combustion structure within the combustion chamber. Eight operating conditions were selected to address the influences of injection pressure, injection timing, and fuel quantity of the first injection on the development of second injection combustion. For some cases with early first injection timing and a small fuel quantity, no liquid fuel is found when luminous flame points appear, which shows that premixed combustion occurs for these cases. However, with the increase of first injection fuel quantity and retardation of the first injection timing, the combustion mode transitions from PCCI combustion to diffusion flame combustion, with liquid fuel being injected into the hot flame. The observed combustion phenomena are mainly determined by the ambient temperature and pressure at the start of the second injection event. The start-of-injection ambient conditions are greatly influenced by the first injection timing, fuel quantity, and injection pressure. Small fuel quantity and early injection timing of the first injection event and high injection pressure are preferable for low sooting combustion.

Nanocrystalline chromium-based coatings deposited by DLI-MOCVD under atmospheric pressure from Cr(CO) 6

Nanocrystalline original Cr-based coatings were grown under atmospheric pressure by Direct Liquid Injection Metal Organic Chemical Vapor Deposition (DLI-MOCVD). The thin films were grown below 450 °C in a cold wall CVD reactor from solutions of Cr(CO) 6 in toluene or THF injected and flash vaporized with or without NH 3 addition prior to the deposition zone. Original nanocrystalline chromium oxycarbide and oxy-carbonitride phases were deposited on stainless steel substrates. The influence of injection parameters and conventional CVD conditions have been investigated on the main chemical, physical and structural characteristics of the coatings, as deduced from XRD, SEM, and EPMA analyses.

Development and validation of a theoretical model for diesel spray penetration

A research on the diesel spray injected into stagnant ambient air in a chamber is reported in this paper. The main objective of the investigation is to carry out an in-depth analysis on the influence of injection parameters on the spray internal dynamics and spray macroscopic characteristics. As a result of a theoretical approach based on momentum flux conservation along the sprays' axis, a model which predicts the spray axis velocity and spray tip penetration is obtained. Measurements of momentum flux and spray cone angle are needed in order to predict axis velocity and spray penetration. The chamber density is assumed to be constant and equal to the density of the pressurized air inside the chamber. A Gaussian radial profile is assumed for the axial velocity. Experimental results from a conventional common rail injection system with five axisymmetric nozzles tested in a wide range of injection pressure values and density conditions have been used in order to obtain additional information of the model and also for validation purposes. These experimental results include a large number of momentum flux (impact force), spray tip penetration and spray cone angle measurements.

Pharmacokinetics of three gadolinium chelates with different molecular sizes shortly after intravenous injection in rabbits: relevance to MR angiography.

To mimic an MR angiographic protocol, an experimental model was developed in rabbits to determine gadolinium concentrations in blood early after injection. Contrast agents with different molecular sizes were compared. The influence of injection parameters (injection rate, duration of injection, volume of injection, dose) was assessed, and two blood pool agents (P760, P717) were compared with the low-molecular-weight Gd-DOTA under similar conditions. Two main phases were identified: bolus and post-bolus. Injection parameters strongly influenced the pattern of the bolus phase, but the postbolus phase was sensitive only to the injected dose. The blood pool agents presented a bolus phase profile similar to that of Gd-DOTA, but 45 seconds after injection, 84% of P717 molecules were still present in the blood compartment, compared with 65% of P760 molecules and only 51% of Gd-DOTA molecules. Blood pool agents are useful for MR angiographic protocols involving the postbolus phase. In protocols in which only the bolus phase is imaged, blood pool agents provide similar data to Gd-DOTA, provided that the injection rate, iso-T1 efficiency dose, and volume are similar.