Longer Injection Time Research Articles

Predictions of the Spray Characteristics of Model Gasoline, Ethanol and Ethanol-in Gasoline Fuel Blends

This paper presents predictions of spray characteristics of model gasoline, ethanol gasoline-ethanol fuel blends. Fuel breakup models and correlations between flow patterns and droplet characteristics were adopted and implemented in OpenFOAM Computational Fluid Dynamics (CFD) modeling suite l for direct gasoline injector using a simple cylindrical mesh structure at constant volume. The Rosin Rammler distribution model was used to generate the number of spray particles injected into the cylinder. The spray modeling and atomization employed the use of blob sheet model and KH-RT model while the numerical technique for simulating atomization process by CFD included the use of governing equations such as Eulerian for gas phase, Lagrangian for disperse phase and turbulence modeling. Spray evolution at various energizing times particle density and The Sauter Mean Diameter (SMD) relationships and particle size distribution were studied in simulation mode. The results showed that with longer injection time frame and wider injection angle, the penetration width was wider and the penetration length deeper (longer) resulting in better atomization. Concerning particle density and its distribution, as number of particle increased, the density of clusters became smaller.

Uncertainty analysis of numerical inversions of temperature logs from boreholes under injection conditions

Abstract Conventional methods to estimate the static formation temperature (SFT) require borehole temperature data measured during thermal recovery periods. This can be both economically and technically prohibitive under real operational conditions, especially for high-temperature boreholes. This study investigates the use of temperature logs obtained under injection conditions to determine SFT through inverse modelling. An adaptive sampling approach based on machine-learning techniques is applied to explore the model space efficiently by iteratively proposing samples based on the results of previous runs. Synthetic case studies are conducted with rigorous evaluation of factors affecting the quality of SFT estimates for deep hot wells. The results show that using temperature data measured at higher flow rates or after longer injection times could lead to less-reliable results. Furthermore, the estimation error exhibits an almost linear dependency on the standard error of the measured borehole temperatures. In addition, potential flow loss zones in the borehole would lead to increased uncertainties in the SFT estimates. Consequently, any prior knowledge about the amount of flow loss could improve the estimation accuracy considerably. For formations with thermal gradients varying with depth, prior information on the depth of the gradient change is necessary to avoid spurious results. The inversion scheme presented is demonstrated as an efficient tool for quantifying uncertainty in the interpretation of borehole data. Although only temperature data are considered in this work, other types of data such as flow and transport measurements can also be included in this method for geophysical and rock physics studies.

Two-Phase Flow Model for Numerical Investigation of Impact of Water Retention on Shale Gas Production

In this work, a triple-porosity, two-phase flow model was established to fill the knowledge gap of previous models focusing on gas production characteristics while ignoring the impacts of water injection. The proposed model considers the water flow in the fracture systems and clay minerals and the gas flow in the organic matter, inorganic pore, and fracture systems. The proposed model is solved using a finite element approach with COMSOL Multiphysics (Version 5.6) and verified with field data. Then, the evolutions of the intrinsic and relative permeabilities during water injection and gas production are examined. Furthermore, the impacts of water injection time and pressure are investigated. Good verification results are obtained; the goodness-of-fit value is 0.92, indicating that the proposed model can replicate both the water stimulation and the gas production stages. The relative gas permeability declines during water injection but recovers in the gas depletion stage. Furthermore, the intrinsic permeability increases during the water injection stage but decreases during the gas production stage. A higher water injection pressure and longer injection time would enlarge the intrinsic permeability, thus improving flow capacity. However, it would reduce gas relative permeability, thereby hindering gas flow. The shale gas production characteristic is controlled by the two abovementioned competing mechanisms. There exists a perfect combination of water injection pressure and injection time for achieving the maximum profitability of a shale gas well. This work can give a better understanding of the two-phase flow process in shale reservoirs and shed light on the field application of hydraulic fracturing.

Use of Mathematical Model to Predict the Maximum Permissible Stage Injection Time for Mitigating Frac-Driven Interactions in Hydraulic-Fracturing Shale Gas/Oil Wells

Abstract Frac-driven interactions (FDIs) often lead to sharp decline in gas and oil production rates of wells in shale gas/oil reservoirs. How to minimize the FDI is an open problem in the oil and gas industry. Xiao et al.’s (2019, “An Analytical Model for Describing Sequential Initiation and Simultaneous Propagation of Multiple Fractures in Hydraulic Fracturing Shale Oil/Gas Formations,” Energy Sci Eng., 7(5), pp. 1514–1526.) analytical model for two-fracture systems was extended in this study to obtain a general model for handling multiple fractures. The general model was used to identify engineering factors affecting the maximum permissible stage fluid injection time for minimizing FDI. On the basis of model results obtained, we found that increasing fluid injection rate can create more short fractures and thus increase the maximum permissible stage injection time before FDI occurs. Use of dilatant type of fracturing fluid (n > 1) can reduce the growth of long fractures, promote the creation of more short fractures, and thus increase the maximum permissible stage injection time before FDI occurs. It is also expected that injecting dilatant type of fracturing fluid at high rate will allow for longer injection time and thus larger injection volume, resulting in larger stimulated reservoir volume (SRV) with higher fracture intensity and thus higher well productivity and hydrocarbon recovery factor.

Protective Effect of Victory Onion (Allium victorialis L.) Extract on Reproductive System Injury in Male Rats

Abstract Aqueous and ethanol extracts of A. victorialis were obtained by reflux extraction. A model of kidney yang deficiency as established by injecting hydrocortisone into male Sprague-Dawley rats. The experimental groups (n=8 rats per group) consisted of blank group, kidney yang deficiency group, and Jingui Shenqi control group (oral administration of Jingui Shenqi herbal preparation). In the treated groups, A. victorialis aqueous or ethanol extract was applied at doses of 1000, 800, or 400 mg/kg. In the model group, kidney yang was associated with loss of appetite, increased drinking water consumption and urine output, and decreased range of activity. With a longer injection time, body weight slowly increased, the body temperature decreased, the response was slow, kyphosis was evident in the back of the bow, and body hair became sparse and lost luster in treated group.

Recovery Mechanisms for Cyclic (Huff-n-Puff) Gas Injection in Unconventional Reservoirs: A Quantitative Evaluation Using Numerical Simulation

Unconventional reservoirs produce large volumes of oil; however, recovery factors are low. While enhanced oil recovery (EOR) with cyclic gas injection can increase recovery factors in unconventional reservoirs, the mechanisms responsible for additional recovery are not well understood. We examined cyclic gas injection recovery mechanisms in unconventional reservoirs including oil swelling, viscosity reduction, vaporization, and pressure support using a numerical flow model as functions of reservoir fluid gas–oil ratio (GOR), and we conducted a sensitivity analysis of the mechanisms to reservoir properties and injection conditions. All mechanisms studied contributed to the additional recovery, but their significance varied with GOR. Pressure support provides a small response for all fluid types. Vaporization plays a role for all fluids but is most important for gas condensate reservoirs. Oil swelling impacts low-GOR oils but diminishes for higher-GOR oil. Viscosity reduction plays a minor role for low-GOR cases. As matrix permeability and fracture surface area increase, the importance of gas injection decreases because of the increased primary oil production. Changes to gas injection conditions that increase injection maturity (longer injection times, higher injection rates, and smaller fracture areas) result in more free gas and, for these cases, vaporization becomes important. Recovery mechanisms for cyclic gas injection are now better understood and can be adapted to varying conditions within unconventional plays, resulting in better EOR designs and improved recovery.

Low Temperature Synthesis of the Carbon Micro Materials

The formation of the carbon microcoils could be achieved under the low temperature (550°C). Ni powders were used as the catalyst on the alumina substrate. C2H2 was used as a source gas and a few amount of SF6 gas were used as an additive gas under the thermal chemical vapor deposition system. The surface morphologies of as-grown carbon materials at the low temperature (550°C) were also investigated according to the total pressure and the injection time of SF6 flow. At 80Torr and 10min injection time of SF6 flow, the carbon microcoils were highly developed on the entire surface of the sample. The lower or higher total pressure and the longer injection time of SF6 flow deteriorated the formation of CMCs. The head area of the carbon microcoils was closely investigated and the growth mode for the initiation of the carbon microcoils at the low temperature was suggested.

Synthesis and characterization of a new vertebroplasty cement based on gold-containing PMMA microspheres

There are a number of drawbacks to incorporating large concentrations of barium sulfate (BaSO4) as the radiopacifier in PMMA-based bone cements for percutaneous vertebroplasty. These include adverse effects on injectability, viscosity profile, setting time, mechanical properties of the cement and bone resorption. We have synthesized a novel cement that is designed to address some of these drawbacks. Its powder includes PMMA microspheres in which gold particles are embedded and its monomer is the same as that used in commercial cements for vertebroplasty. In comparison to one such commercial cement brand, VertaPlex™, the new cement has longer doughing time, longer injection time, higher compressive strength, higher compressive modulus, and is superior in terms of cytotoxicity. For augmentation of fractured fresh-frozen cadaveric vertebral bodies (T6-L5) using simulated vertebroplasty, results for compressive strength and compressive stiffness of the construct and the percentage of the volume of the vertebral body filled by the cement were comparable for the two cements although the radiopacity of the new cement was significantly lower than that for VertaPlex™. The present results indicate that the new cement warrants further study.

Reversible phospholipid nanogels for deoxyribonucleic acid fragment size determinations up to 1500 base pairs and integrated sample stacking

Phospholipid additives are a cost-effective medium to separate deoxyribonucleic acid (DNA) fragments and possess a thermally-responsive viscosity. This provides a mechanism to easily create and replace a highly viscous nanogel in a narrow bore capillary with only a 10°C change in temperature. Preparations composed of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) self-assemble, forming structures such as nanodisks and wormlike micelles. Factors that influence the morphology of a particular DMPC–DHPC preparation include the concentration of lipid in solution, the temperature, and the ratio of DMPC and DHPC. It has previously been established that an aqueous solution containing 10% phospholipid with a ratio of [DMPC]/[DHPC]=2.5 separates DNA fragments with nearly single base resolution for DNA fragments up to 500 base pairs in length, but beyond this size the resolution decreases dramatically. A new DMPC–DHPC medium is developed to effectively separate and size DNA fragments up to 1500 base pairs by decreasing the total lipid concentration to 2.5%. A 2.5% phospholipid nanogel generates a resolution of 1% of the DNA fragment size up to 1500 base pairs. This increase in the upper size limit is accomplished using commercially available phospholipids at an even lower material cost than is achieved with the 10% preparation. The separation additive is used to evaluate size markers ranging between 200 and 1500 base pairs in order to distinguish invasive strains of Streptococcus pyogenes and Aspergillus species by harnessing differences in gene sequences of collagen-like proteins in these organisms. For the first time, a reversible stacking gel is integrated in a capillary sieving separation by utilizing the thermally-responsive viscosity of these self-assembled phospholipid preparations. A discontinuous matrix is created that is composed of a cartridge of highly viscous phospholipid assimilated into a separation matrix of low viscosity. DNA sample stacking is facilitated with longer injection times without sacrificing separation efficiency.

Control of Biofouling: Lessons Learned From a Decade of Carbon Injection System Operation and Maintenance

AbstractOver the past decade, we have learned a number of critical lessons surrounding carbon substrate handling while operating and maintaining hundreds of enhanced in situ biological remedies. The same qualities that make these substrates effective can also cause biofouling of the mixing system, piping infrastructure, and remediation wells. Managing biofouling is a key piece of a successful remedy and requires a unique set of design principles. Small decreases in injection rates can have considerable impacts to life‐cycle costs and performance caused by decreased substrate distribution and longer injection time frames, resulting in the need for system cleaning, well rehabilitation, and even well replacement. Biofouling can impair performance in any size system, but effects are often magnified by large injection volumes and extended time frames. Design should be considered in all stages of the anaerobic enhanced in situ bioremediation life cycle, particularly related to reagent mixing, storage, and residence time within the system. By understanding the fundamental mechanisms of biofouling, practitioners can make operational adjustments to enhance remedy performance by considering potential biofouling controls in the design; balancing site‐specific strategy and diagnostics; and proactively adjusting and fine tuning control/prevention technology and methodology.Ultimately, a combination of chemical and physical methods may be required to operate a carbon handling system over the long term; however, the operational costs can be greatly reduced and delivery efficiency increased if these methods are understood during the design phase. © 2013 Wiley Periodicals, Inc.

Injection molding analysis of a needle cover — Optimum filling for gate location design

Injection molding is one of the most popular manufacturing methods for the cost-effective mass production of the plastic parts. Filling analysis of the molten polymer provides useful information to investigate the process conditions to ensure successful replication. To validate appropriate gate location for a NEEDLE COVER, flow fronts and flow stresses for four different gating options and three different design options are analyzed and compared to the field results. Based on the results, the optimum gate location for the minimum flow stresses and uniform fill patterns appears to be at gate 3. Thus it also provides minimum possibility of part warpage throughout PORT HOUSING and NEEDLE HOUSING. The results of analysis on the increased wall thickness, lower melt temperature, and longer injection time indicated that higher melt temperatures were recommended to achieve successful molding. Injecting the polymer at a longer time (1.2 second) leads to a significant increase in flow stresses throughout the part and the increase of wall thickness achieve successful replication of the parts.

Formation of the Geometrically Controlled Carbon Coils by Manipulating the Additive Gas (SF6) Flow Rate

Carbon coils could be synthesized using C2H2/H2 as source gases and SF6 as an incorporated additive gas under the thermal chemical vapor deposition system. The nickel catalyst layer deposition and then hydrogen plasma pretreatment were performed prior to the carbon coils deposition reaction. The flow rate and the injection time of SF6 varied according to the different reaction processes. Geometries of carbon coils developed from embryos to nanosized coils with increasing SF, flow rate from 5 to 35 sccm under the short SF6 flow injection time (5 minutes) condition. The gradual development of carbon coils geometries from nanosized to microsized types could be observed with increasing SF6 flow rate under the full time (90 minutes) SF6 flow injection condition. The flow rate of SF6 for the coil-type geometry formation should be more than or at least equal to the flow rate of carbon source gas (C2H2). A longer injection time of SF6 flow would increase the size of coils diameters from nanometer to micrometer.

Analysis of high gradient magnetic field effects on distribution of nanoparticles injected into pulsatile blood stream

Magnetic nanoparticles are widely used in a wide range of applications including data storage materials, pharmaceutical industries as magnetic separation tools, anti-cancer drug carriers and micro valve applications. The purpose of the current study is to investigate the effect of a non-uniform magnetic field on bio-fluid (blood) with magnetic nanoparticles. The effect of particles as well as mass fraction on flow field and volume concentration is investigated. The governing non-linear differential equations, concentration and Navier–stokes are coupled with the magnetic field. To solve these equations, a finite volume based code is developed and utilized. A real pulsatile velocity is utilized as inlet boundary condition. This velocity is extracted from an actual experimental data. Three percent nanoparticles volume concentration, as drug carrier, is steadily injected in an unsteady, pulsatile and non-Newtonian flow. A power law model is considered for the blood viscosity. The results show that during the systole section of the heartbeat when the blood velocity increases, the magnetic nanoparticles near the magnetic source are washed away. This is due to the sudden increase of the hydrodynamic force, which overcomes the magnetic force. The probability of vein blockage increases when the blood velocity reduces during the diastole time. As nanoparticles velocity injection decreases (longer injection time) the wall shear stress (especially near the injection area) decreases and the retention time of the magnetic nanoparticles in the blood flow increases.

Effects of Processing Parameters on Flow-Induced Crystallization of iPP in Microinjection Molding

Flow-induced crystallization has long been an important subject in polymer processing. Varying processing conditions can produce different morphologies, which lead to different properties. Recent studies have indicated that the final morphology is, in fact, dictated by the formation of crystallization structures under flow. This study deals with the influence of processing parameters on the polymorphism and crystallization orientation of isotactic polypropylene (iPP) in microinjection molding. Crystallinity and polymorphism were investigated by means of differential scanning calorimeter (DSC) and one-dimensional wide-angle X-ray diffraction (1D-WAXD). Crystalline orientation was characterized by two-dimensional wide-angle X-ray diffraction (2D-WAXD). Herman's orientation functions determined from the flat-plate wide-angle X-ray diffraction patterns were used to evaluate the orientation level of microparts. It was found that the effect of processing parameters on the crystallinity was not obvious, but these processing parameters had a great influence on the β-modification content of microparts. When the mold temperature was 150°C, β-modification still formed in microparts because the thermal stability of the β-modification was enhanced with increasing the mold temperature; The β-modification content of microparts decreased obviously when the injection time was 1 s compared to the longer injection time. However, the β-modification content of microparts increased with increasing the injection pressure. In addition, the γ-modification existed in the microparts at the mold temperatures of 150 and 160°C. From Herman's orientation functions, we know that the influence of processing parameters on α-crystalline orientation in microparts was small. But the processing parameters can affect the degree of the β-modification orientation. A shish-kebab structure was observed in some regions throughout the longitudinal sections of all the microparts by the SEM analysis.

Pain and Efficacy Rating of a Microprocessor-Controlled Metered Injection System for Local Anaesthesia in Minor Hand Surgery

Purpose. Little attention has been given to syringe design and local anaesthetic administration methods. A microprocessor-controlled anaesthetic delivery device has become available that may minimize discomfort during injection. The purpose of this study was to document the pain experience associated with the use of this system and to compare it with use of a conventional syringe. Methods. A prospective, randomized clinical trial was designed. 40 patients undergoing carpal tunnel release were block randomized according to sex into a two groups: a traditional syringe group and a microprocessor-controlled device group. The primary outcome measure was surgical pain and local anaesthetic administration pain. Secondary outcomes included volume of anaesthetic used and injection time. Results. Analysis showed that equivalent anaesthesia was achieved in the microprocessor-controlled group despite using a significantly lower volume of local anaesthetic (P = .0002). This same group, however, has significantly longer injection times (P < .0001). Pain during the injection process or during surgery was not different between the two groups. Conclusions. This RCT comparing traditional and microprocessor controlled methods of administering local anaesthetic showed similar levels of discomfort in both groups. While the microprocessor-controlled group used less volume, the total time for the administration was significantly greater.

Simultaneous enantioseparation and sensitivity enhancement of basic drugs using large‐volume sample stacking

Simultaneous enantioseparation with sensitive detection of four basic drugs, namely methoxamine, metaproterenol, terbutaline and carvedilol, using a 20-mum ID capillary with native beta-CD as the chiral selector was demonstrated by the large-volume sample stacking method. The procedure included conventional sample loading either hydrodynamically or electrokinetically at longer injection times without polarity switching and EOF manipulation. In comparison to conventional injections, depending on the analyte, about several hundred- and a thousand-fold sensitivity enhancement was achieved with the hydrodynamic and the electrokinetic injections, respectively. The simple method developed was applied to the analysis of racemic analytes in serum samples and better recovery was achieved using hydrodynamic injection than electrokinetic injection.

Pressure‐assisted field‐amplified sample injection with reverse migrating micelles for analyzing trace steroids in MEKC

This paper describes a novel method that applies pressure-assisted field-amplified sample injection with reverse migrating micelles (PA-FASI-RMM) for the online concentration of neutral analytes in MEKC with a low-pH BGE. After injection of a plug of water into the separation capillary, negative voltage and positive pressure were simultaneously applied to initialize PA-FASI-RMM injection. The hydrodynamic flow generated by the positive pressure compensated the reverse EOF in the water plug and allowed the water plug to remain in the capillary during FASI with reverse migrating micelles (FASI-RMM) to obtain a much longer injection time than usual, which improved stacking efficiency greatly. Equations describing this injection mode were introduced and were supported by experimental results. For a 450-s online PA-FASI-RMM injection, three orders of magnitude sample enhancement in terms of peak area could be observed for the steroids and an achievement of detection limits was between 1 and 10 ng/mL.

Anticipated Diagnosis of Adverse Events after Stem Cell Transplantation Using Highly Sensitive STR-PCR for Chimerism Quantification.

Introduction: The current gold standard for chimerism quantification after allo-stem cell transplantation (SCT) is based on the polymerase chain reaction of DNA short tandem repeats (STR-PCR). This methodology is sex-independent, highly informative and quantitatively accurate. However, this method has a moderate sensitivity (1–3%).Objective: To test the usefulness of increasing the assay sensitivity by 3 different approaches in order to detect recipient residual cells.Material and Methods: Two sets of 20 samples, belonging to artificial mixtures of male and female peripheral blood (PB) cells in different proportions (% male: 100, 75, 50, 25, 10, 5, 3, 1, 0.1, 0) were prepared to test the assay sensitivity and reproducibility. Additionally 58 samples from 10 selected patients showing different clinical evolution post-SCT were retrospectively studied. Chimerism was analyzed on genomic DNA (purified QIAamp DNA blood kit, Qiagen) by multiplex STR-PCR (AmpFlSTR SGM Plus revealed on capillary electrophoresis in an ABI Prism 3100 automated DNA sequencer; Applied Biosystems). Three different approaches aimed to increase the sensitivity of STR-PCR were tested: (1) Increasing DNA concentration in the PCR (1x, 2.5x, 5x), (2) Increasing the concentration of the PCR product for the capillary electrophoresis (1x, 2.5x, 5x) and (3) Increasing the sample injection time into the capillary for the electrophoresis (10s, standard time, 30s and 50s).Results: The standard STR-PCR showed a sensitivity of 1% in both sets of male-female PB artificial mixtures. Both approaches increasing DNA concentration in the PCR and the PCR product in the capillary electrophoresis did not achieved better sensitivity. Moreover, appropriate analysis of the samples was frequently hampered due to fluorescence saturation. However, longer injection times (30s, 50s) showed that currently underrepresented DNA fragments were conspicuously overestimated, giving a one-log increase in the sensitivity of the STR-PCR assay, which reached a 0.1%. This approach was used to re-analyze the 23 SCT patient samples previously identified as in complete chimerism by standard STR-PCR. The 0.1% sensitivity methodological approach allowed to detect residual/reappearing recipient cells in three of the 23 analyzed samples. Therefore this new approach would have allowed to anticipate the detection of graft rejection and disease relapse in 2/10 patients, 7 and 77 days respectively.Conclusion: Long injection times (30s and 50s) in the capillary electrophoresis after STR-PCR result in a one log sensitivity increase (from 1% to 0.1%). This would allow earlier diagnosis of adverse events after SCT favoring a prompt introduction of therapeutic interventions.

CO/UNBURNED HYDROCARBON EMISSIONS OF STRONGLY-PULSED TURBULENT DIFFUSION FLAMES

The CO and unburned hydrocarbon (UHC) emissions of pulsed turbulent diffusion flames were examined by injecting unheated ethylene into a combustor with an air coflow at atmospheric pressure. In all cases the flames were fully modulated (fuel flow fully shut off between injection intervals). Video imaging was performed and time-averaged emissions were measured on the combustor centerline. For short injection times ( ≤ 46 ms), compact, puff-like structures were generated. Longer injection times produced elongated flame structures with flame lengths closer to that of steady flames. The highest emission indices of CO and UHC were found for compact, isolated puffs. The emissions for all flames approached the steady-flame levels for a duty cycle (jet-on fraction) of approximately 0.4. This suggests that there are combinations of injection time and duty cycle for fully modulated, turbulent diffusion flames that produce emissions comparable to the steady flame but with a significantly shorter flame length.

Structure and Flame Length of Fully-Modulated, Turbulent Diffusion Flames

The turbulent flame structure and flame length of fully-modulated diffusion flames was examined over a range of pulsing frequencies, injection flow rates, and duty-cycles. An injection system employing an electronically-controlled solenoid value was used to discharge puffs of unhealed natural gas and ethylene fuel into still air at one atmosphere pressure. Video imaging of the luminosity from the sooting regions of the flame revealed two distinct types of flame structure. For small injected volumes and short injection times, compact, puff-like structures with a short flame length were generated. More elongated “cigar-shaped” structures, with a longer flame length closer to that of steady-state flames, resulted from longer injection times and larger injected volumes. An injection parameter which characterizes the transition from puff-like to cigar-shaped flame behavior is presented. For puffs, an increase in duty-cycle generally led to an increase in flame length. This increase was less for cigar-shaped flames. The downstream location of the puff-like flame structures increased roughly with time to the 1/2 power, in agreement with buoyant thermals and starting jets.