Injection Location Research Articles

Impact of the Latitude of Stratospheric Aerosol Injection on the Southern Annular Mode

AbstractThe impacts of Stratospheric Aerosol Injection (SAI) strategies on the Southern Annular Mode (SAM) are analyzed with the Community Earth System Model. Using a set of simulations with fixed single‐point SO2 injections we demonstrate the first‐order dependence of the SAM response on the latitude of injection, with the northern hemispheric and equatorial injections driving a response corresponding to a positive phase of SAM and the southern hemispheric injections driving a negative phase of SAM. We further demonstrate that the results can to first order explain the differences in the SAM responses diagnosed from the two recent large ensembles of geoengineering simulations utilizing more complex injection strategies – Geoengineering Large Ensemble and Assessing Responses and Impacts of Solar climate intervention on the Earth system with Stratospheric Aerosol Injection (GLENS and ARISE‐SAI) – as driven by the differences in the simulated sulfate aerosol distributions. Our results point to the meridional extent of aerosol‐induced lower stratospheric heating as an important driver of the sensitivity of the SAM response to the injection location.

Experimental and numerical analysis of film cooling performance of a corrugated surface

ABSTRACT The present study proposes a suitable injection configuration and operating parameters for the film cooling of an aero-engine afterburner, based on experimental and numerical studies. The experimental investigations are carried out for different injection locations for blowing ratios 0.5 and 1, fixed injection angle (45°), and density ratio (1.095). The numerical study is extended for various injection locations with a wide range of operating parameters such as blowing ratios from (0.25–3), density ratios (1.095, 2.5, and 4), and different pressure ratios from 1 to 15, representing the operating conditions of an actual aero-engine afterburner. The present study reveals that the film cooling on the corrugated surface is strongly influenced by the secondary stream injection locations and corrugation amplitude to wavelength ratio. This study also shows that the film cooling behavior on a corrugated surface is inherently different from that a flat surface; the centreline effectiveness plots show improvements even at a higher blowing ratio (i.e. 2). The density ratio also shows a significant impact on film cooling performance, and with an increase in density ratio from 1.095 to 2.5, the centreline effectiveness increases.

Bifurcation in Rotating Detonation Engine Operation with Continuously Variable Fuel Injection Location

Sensitivity of rotating detonation engine operation and performance to the location of fuel injection was characterized using continuous variation of the injector geometry during an experiment. The fuel injector location was translated in relation to the oxidizer throat in a jet-in-crossflow configuration to study the influence of injection dynamics on combustor operation. The injector was translated toward and away from the stationary oxidizer throat for a range of operating conditions. High-speed measurements of pressure and flame chemiluminescence intensity, along with thrust, were used to characterize the detonation wave propagation in the experiment and evaluate combustor performance. Higher wave speeds were observed at injector locations closest to the oxidizer throat, with decreased wave speed and eventual transition to deflagrative operation occurring at locations farther downstream. Variation in fuel injection location induced bifurcations in the number of waves, resulting in corresponding changes in wave speed and gross thrust. Hysteresis was observed in these quantities as the direction of injector translation was reversed. Active translation promoted detonative operation of the experiment at conditions and configurations that hitherto operated only in a deflagrative mode with fixed combustor geometry.

Automatized Experimental Combustor Development Using Adaptive Surrogate Model-Based Optimization

Abstract Lean premixed combustion is the state-of-the-art technology to achieve ultra low NOx emissions in stationary gas turbines. However, lean premixed flames are susceptible to thermoacoustic instabilities, lean blowout, and flashback. The design of such a combustion system is thus always related to the balancing between the levels of emissions and flame stability. Data-driven optimization methods and the adaptation of models through artificial intelligence have experienced a surge in development in the past years. The goal of this study is to show the potential of these methods for gas turbine burner development. A special pilot burner that features 61 different positions of fuel injection, manufactured by means of selective laser melting is used to modify the gas mixture close to the flame anchoring position. Each of the injector lines is equipped with an individual valve, such that the distribution of fuel-air mixture can be modified variously. Installed into an industrial MGT6000 swirl combustor, a data-driven optimization method is used to find an optimal subset of injection locations by automated experiments. The method uses a surrogate model that is based on Gaussian processes regression. It is adopted for experimental optimization, keeping measurement efforts to a minimum. The optimizer controls the fuel valves and uses live measurements to find a distribution that generates minimal NOx emissions while ensuring flame stability. The solutions found by the optimization scheme are analyzed and advantages and limitations of the approach are discussed.

Intravesical botulinum toxin: Practice patterns from a survey of Canadian urologists.

The objectives of this study were to conduct a survey of intravesical botulinum toxin administration practices in Canada, to compare practices based on level of training, and to identify barriers to delivery. A voluntary online survey was sent to all members of the Canadian Urological Association. Respondents who provide intravesical botulinum toxin were questioned on training, surgical volume, workup, technique, and followup practices. Those with formal training in functional urology were compared to those without. Barriers to treatment delivery were identified. The overall response rate was 26% (148/570). Most providers (59%) perform 1-10 treatments/month. Preoperatively, 51% perform cystoscopy and 43% perform urodynamics. A majority (66%) give routine antimicrobial prophylaxis; however, regimen and duration varied. Most (79%) perform some treatments under local anesthetic, and 66% instill lidocaine solution for analgesia. There was a wide variation in technique with regards to the number of injections administered (range <10 to >20), volume administered per injection (range 0.5-2 mL), location of injections (bladder body vs. trigone vs. both), and depth of injection. Postoperative followup ranged from three days to three months. Respondents with fellowship training in functional/reconstructive urology performed more treatments per month and administered fewer injections per treatment. Common barriers to delivery included lack of experience/training among non-providers (45%), lack of resources (34%), and lack of medication funding (32%). Despite intravesical botulinum toxin being a widely accepted treatment, significant variability in practices and several barriers to delivery exist in Canada. Further study is required to optimize treatment access and quality.

Determination of extreme responses of USFG's equilibrium glide path hovering in ocean current

The UiS subsea-freight glider (USFG) is a state-of-the-art autonomous vessel designed to be an alternative to existing transportation technologies and serve the demands of small-scale fields for CO2 transportation. Generally, these smaller fields cannot economically justify the costs of large tankers, cargo ships, or underwater pipelines on the seabed, as the transport volume is nominal compared to larger fields. The USFG can travel underwater at an operational depth of 200 m, allowing the glider to carry freight operations without considering ideal weather windows. It can manoeuvre itself underwater by monitoring the flow between the ballast tanks aboard. During the entire mission of the USFG, from capturing to injection locations, it follows a pre-laid saw-tooth path while experiencing transient loads from the ocean current. The extreme surge and heave responses of the USFG are vital for its design. Extreme motion along the surge direction affects the range of the glider (vital for battery design) and the dynamic controller parameters concerning manoeuvrability. For this paper, the averaged conditional exceedance rate (ACER) is employed to scrutinize the extreme motion (surge direction) of the USFG while gliding to a defined depth. This is done when the glider is exposed to an average current velocity of 0.5 m/s and 1.0 m/s. The data used for analysis in this study is obtained from the time-domain simulations carried out on a two-dimensional mathematical model developed in Simulink. The presented ACER method efficiently uses the available data points and accurately predicts the extreme surge responses precisely and accurately. This study can effectively promote the design improvement of the USFG; thus, the safety and economic benefits can be essentially enhanced.

Molecular and spatial epidemiology of HCV among people who inject drugs in Boston, Massachusetts.

Integration of genetic, social network, and spatial data has the potential to improve understanding of transmission dynamics in established HCV epidemics. Sequence data were analyzed from 63 viremic people who inject drugs recruited in the Boston area through chain referral or time-location sampling. HCV subtype 1a was most prevalent (57.1%), followed by subtype 3a (33.9%). The phylogenetic distances between sequences were no shorter comparing individuals within versus across networks, nor by location or time of first injection. Social and spatial networks, while interesting, may be too ephemeral to inform transmission dynamics when the date and location of infection are indeterminate.

Effect of self-recirculating casing treatment on the unsteady flow and stability of counter-rotating axial-flow compressor

Abstract Counter-rotating axial-flow compressor (CRAC) is a promising technology to enhance the thrust-to-weight ratio of aero-engines. Self-recirculating casing treatment (SRCT) is an efficient flow control technique for increasing stall margin in conventional compressors. With the purpose of investigating the applicability and mechanism of SRCT in the CRACs, a two-stage CRAC is selected to investigate the stability enhancement mechanism of SRCT and its effect on the unsteady flow near the rotor tip, and the effect of injector location on the stability improvement capacity of SRCT is also studied. Results show that about 7.73% stall margin improvement can be achieved by configuring the SRCT on the near rotor top, and the injector location also has a significant influence on the stability expansion potential of SRCT. The SRCT delays the stall occurrence by weakening the intensity of tip leakage flow (TLF) and restraining the leading-edge spillages of TLF. The SRCT reduces the unsteady interference between the adjacent rotors by receding the disturbance of the upstream wake and inhibiting the potential flow effect of the downstream. Furthermore, the SRCT reduces the self-excited oscillation frequency of TLF and damps its fluctuation amplitude.

Experimental study on co-firing characteristics of ammonia with pulverized coal in a staged combustion drop tube furnace

Utilizing ammonia as a co-firing fuel to replace amounts of fossil fuel seems a feasible solution to reduce carbon emissions in existing pulverized coal-fired power plants. However, there are some problems needed to be considered when treating ammonia as a fuel, such as low flame stability, low combustion efficiency, and high NOx emission. In this study, the co-firing characteristics of ammonia with pulverized coal are studied in a drop tube furnace with staged combustion strategy. Results showed that staged combustion would play a key role in reducing NOx emissions by reducing the production of char-NOx and fuel(NH3)-NOx simultaneously. Furthermore, the effects of different ammonia co-firing methods on the flue gas properties and unburned carbon contents were compared to achieve both efficient combustion and low NOx emission. It was found that when ammonia was injected into 300 mm downstream under the condition of 20% co-firing, lower NOx emission and unburnt carbon content than those of pure coal combustion can be achieved. This is probably caused by a combined effect of a high local equivalence ratio of NH3/air and the prominent denitration effect of NH3 in the vicinity of the NH3 downstream injection location. In addition, NOx emissions can be kept at approximately the same level as coal combustion when the co-firing ratio is below 30%. And the influence of reaction temperature on NOx emissions is closely associated with the denitration efficiency of the NH3. Almost no ammonia slip has been detected for any injection methods and co-firing ratio in the studied conditions. Thus, it can be confirmed that ammonia can be used as an alternative fuel to realize CO2 reduction without extensive retrofitting works. And the NOx emission can be reduced by producing a locally NH3 flame zone with a high equivalence ratio as well as ensuring adequate residence time.

A Generic Closed-Loop Contaminant Treatment System Package for MODFLOW 6.

We present a contaminant treatment system (CTS) package for MODFLOW 6 that facilitates the simulation of pump-and-treat systems for groundwater remediation. Using the "nonintrusive" MODFLOW 6 application programming interface (API) capability, the CTS package can balance flows between extraction and injection wells within the outer flow solution loop and applies blended concentration/mass treatment efficiency within the outer transport solution loop. The former can be important when the requested extraction rate cannot be satisfied by the current simulated groundwater system conditions, while the latter can be important for simulating incomplete/imperfect treatment schemes. Furthermore, the CTS package allows users to temporally vary all aspects of a simulated CTS system, including the configuration and location of injection and extraction wells, and the CTS efficiency. This flexibility combined with the API-based implementation provide a generic and general CTS package that can be applied across the wide range of MODFLOW 6 simulation options and that evolves in step with MODFLOW 6 code modifications and advancements without needing to update the CTS package itself.

Association between BNT162b2 vaccination and the development of delayed inflammatory reactions to hyaluronic acid-based dermal fillers-A nationwide survey.

BackgroundDelayed inflammatory reactions (DIRs) to hyaluronic acid (HA)‐based dermal fillers following COVID‐19 vaccination has been reported in a few anecdotal reports and small series of cases.AimTo evaluate the clinical characteristics, incidence and management options relevant to BNT162b2 vaccination‐associated DIR – A nationwide survey was conducted.MethodsAn online self‐administered survey was sent to physicians who actively practice tissue filler injections. The data acquired included demographic and clinical characteristics of relevant DIR cases.ResultsOut of 262 responders, 20 cases with DIR following the vaccination were reported. 35% and 65% occurred shortly after the first and second vaccination dose, respectively. Overall, 65% of the DIRs appeared ≤5 days after vaccine administration and most DIRs resolved within 21 days. The filler's volume (P = .016) was associated with higher DIR severity, and the same tendency was noted among some filler types and locations of injection. Medical intervention was provided in 12 (60%) cases.ConclusionDIR associated with BNT162b2 vaccination is rare and tends to resolve spontaneously or with short‐term medical intervention.

Modelling of Nanoparticle Distribution in a Spherical Tumour during and Following Local Injection.

Radio-sensitizing nanoparticles are a potential method to increase the damage caused to cancerous cells during the course of radiotherapy. The distribution of these particles in a given targeted tumour is a relevant factor in determining the efficacy of nanoparticle-enhanced treatment. In this study, a three-part mathematical model is shown to predict the distribution of nanoparticles after direct injection into a tumour. In contrast with previous studies, here, a higher value of diffusivity for charged particles was used and the concentration profile of deposited particles was studied. Simulation results for particle concentrations both in the interstitial fluid and deposited onto cells are compared for different values of particle surface charges during and after injection. Our results show that particles with a negative surface charge can spread farther from the injection location as compared to uncharged particles with charged particles occupying 100% of the tumour volume compared to 8.8% for uncharged particles. This has implications for the future development of radiosensitizers and any associated trials.

Numerical Modeling of Structurally Controlled Ore Formation in Magmatic‐Hydrothermal Systems

AbstractFaults and fractures can be permeable pathways for focused fluid flow in structurally controlled ore‐forming hydrothermal systems. However, quantifying their role in fluid flow on the scale of several kilometers with numerical models typically requires high‐resolution meshes. This study introduces a modified numerical representation of m‐scale fault zones using lower‐dimensional elements (here, one‐dimensional [1D] elements in a 2D domain) to resolve structurally controlled fluid flow with coarser mesh resolutions and apply the method to magmatic‐hydrothermal ore‐forming systems. We modeled horizontal and vertical structure‐controlled magmatic‐hydrothermal deposits to understand the role of permeability and structure connectivity on ore deposition. The simulation results of vertically extended porphyry copper systems show that ore deposition can occur along permeable vertical structures where ascending, overpressured magmatic fluids are cooled by downflowing ambient fluids. Structure permeability and fault location control the distribution of ore grades. In highly permeable structures, the mineralization can span up to 3 km vertically, resulting in heat‐pipe mechanisms that promote the ascent of a magmatic vapor phase to an overlying structurally controlled epithermal system. Simulations for the formation of subhorizontal vein‐type deposits suggest that the major control on fluid flow and metal deposition along horizontal structures is the absence of vertical structures above the injection location but their presence at greater distances. Using a dynamic permeability model mimicking crack‐seal mechanisms within the structures leads to a pulsating behavior of fracture‐controlled hydrothermal systems and prevents the inflow of ambient fluids under overpressured conditions.

The Role of Background Stress State in Fluid‐Induced Aseismic Slip and Dynamic Rupture on a 3‐m Laboratory Fault

AbstractFluid injection stimulates seismicity far from active tectonic regions. However, the details of how fluids modify on‐fault stresses and initiate seismic events remain poorly understood. We conducted laboratory experiments using a biaxial loading apparatus with a 3 m saw‐cut granite fault and compared events induced at different levels of background shear stress. Water was injected at 10 mL/min and normal stress was constant at 4 MPa. In all experiments, aseismic slip initiated on the fault near the location of fluid injection and dynamic rupture eventually initiated from within the aseismic slipping patch. When the fault was near critically stressed, seismic slip initiated only seconds after MPa‐level injection pressures were reached and the dynamic rupture propagated beyond the fluid pressure perturbed region. At lower stress levels, dynamic rupture initiated hundreds of seconds later and was limited to regions where aseismic slip had significantly redistributed stress from within the pressurized region to neighboring locked patches. We found that the initiation of slow slip was broadly consistent with a Coulomb failure stress, but that initiation of dynamic rupture required additional criteria to be met. Even high background stress levels required aseismic slip to modify on‐fault stress to meet initiation criteria. We also observed slow slip events prior to dynamic rupture. Overall, our experiments suggest that initial fault stress, relative to fault strength, is a critical factor in determining whether a fluid‐induced rupture will “runaway” or whether a fluid‐induced rupture will remain localized to the fluid pressurized region.

Effects of in ovo injection of nicotinamide riboside on high-yield broiler myogenesis.

The objective of this study was to determine the effects of in ovo injection of high-yield broiler embryos with nicotinamide riboside (NR) on pectoralis major muscle (PMM) development, growth, and gene expression. Fertilized Cobb 700 broiler eggs were randomly assigned to one of four treatments within a 2 × 2 factorial design. Factor 1 consisted of NR dose (DOS) with eggs receiving 0 or 2.5 mM NR. Factor 2 consisted of injection location (LOC), with treatments injected into either the yolk sac or albumen. At day 10 of incubation, 100 μL of the assigned NR dose was injected into the yolk sac of the developing embryo and chicks were euthanized within 24 h of hatching. Chick PMM and individual fiber morphometrics, and expression of genes associated with cell cycle progression were analyzed. There were DOS × LOC interactions for hatched chick PM weight and length (P < 0.04). When NR was injected into the albumen, PMM weight decreased (P < 0.05); when NR was injected into the yolk, PMM weight increased (P < 0.05). Pectoralis major length was not affected (P > 0.05) when NR was injected into the albumen but was increased (P < 0.05) when NR was injected into the yolk. There was a DOS × LOC interaction (P = 0.04) for muscle fiber density and tended to be a DOS × LOC interaction (P = 0.07) for muscle fiber CSA. Pectoralis major muscle fiber density was not affected when NR was injected into the albumen (P > 0.05), but density increased when NR was injected into the yolk (P < 0.05). There were DOS × LOC interactions for hatched chick COXII, cyclin D, and SIRT1 expression (P ≤ 0.04), which may indicate NR improves skeletal muscle development and growth by enhancing myoblast proliferation during embryonic development.

Impacts of preferential vaporization on flashback behaviors of multi-component liquid fuels

Liquid transportation fuels are composed of a wide range of molecular structures and weights, therefore exhibiting a relatively large distillation temperature range. When fuel chemical properties change along with the distillation temperature curve, preferential vaporization effects could play a role in near-limit combustion behaviors. The objective of this study is to experimentally evaluate the role of preferential vaporization on flame flashback behaviors. A unique spray burner is developed to control the extent of fuel spray vaporization by adjusting flow rates and/or the spray injection location from the burner exit. Spray characteristics are comprehensively determined using Phase Doppler Particle Analyzer. Two binary component mixtures are formulated (n-octane/iso-cetane and iso-octane/n-hexadecane) to exhibit common combustion behaviors in the fully vaporized condition but have considerably different preferential vaporization characteristics. Identical flashback behaviors of two mixtures are observed for fully pre-vaporized conditions by setting the burner temperature at 700 K, including both propagation- and ignition-driven flashback behaviors. Partially vaporized conditions are investigated at two global equivalence ratios (1.0 and 1.4) by setting the burner temperature at 450 K. The flashback behaviors for both global equivalence ratio conditions are found to be affected by the preferential vaporization characteristics represented by laminar flame speeds of the vaporized fuel mixture composition. The relative significance of local flow perturbation induced by instantaneous fuel droplet evaporation near the flame surface has been also investigated by analyzing planar laser-induced fluorescence images, as well as considering the changes of Markstein length with the extent of fuel vaporization. Finally, the relative contributions of local laminar flame speed representing local fuel vapor deposit, local flow perturbation, and preferential vaporization are evaluated through feature sensitivity analyses.

Comparison of Drag Reduction Effect on Barge Model Ship Using Ultrafine Bubble and Microbubble Injection

nergy efficiency is a global goal in the fight against global warming. Research on reducing drag is one of the ways to improve energy efficiency. The research method used is the injection of micro-sized bubbles and ultra-fine bubbles used in the barge ship model. Microbubble Drag Reduction (MBDR) and Ultrafine Bubble Drag Reduction (UFBDR) are two methods that can play an essential role in reducing drag on the surface of the ship's hull. Factors that can affect the effectiveness of these methods are the injection ratio, location, and coefficient of drag produced by both methods. The injection method discussed the use of the method, which was reviewed on a 2-meter towing tank and compared the two injection methods. The results provided by this research are to determine the injection ratio and the optimum injection location on the model ship and compare the effect of reducing drag and drag coefficient. The increases total resistance reduction of 6.87% compared to the reduction in resistance by microbubble injection.

A hybrid optimization algorithm for gate locations in the liquid composite molding process

It is costly to optimize the location of multiple injection gates through a trial and error-based method in the liquid composite molding, even though there are high fidelity physics-based numerical models. A hybrid optimization method called the Simulated Annealing Genetic Algorithm is proposed in this article, which uses the genetic algorithm to provide a global search for a predetermined time and then is further improved by the simulated annealing algorithm. The optimization results of multiple injection gates show that the number of convergence iterations using the Simulated Annealing Genetic Algorithm is less than that using the genetic algorithm, and the phenomenon becomes more obvious as the number of injection gates increases. The case shows that the Simulated Annealing Genetic Algorithm can solve the multiple injection gate configuration problems of highly anisotropic laminates without extra work. The optimization results are in good agreement with the experimental results.

Coordinated operation of electricity and gas-hydrogen systems with transient gas flow and hydrogen concentration tracking

This paper addresses the problem of coordinating the operation of electricity and natural gas (NG) transmission systems with green hydrogen (H2) production and injection into existing NG networks. In particular, the operation of the two systems consists of a two-stage optimization framework that solves a network-constrained unit commitment (UC) problem with transmission power losses to obtain the profiles of gas energy demands from gas-powered generators and the maximum allowable H2 injection flow rates from power-to-gas (PtG), which are then used as inputs to an optimal transient NG-H2 flow problem with H2 concentration tracking. The nonlinearities introduced by the discretization of the H2 concentration tracking equations are particularly challenging to solve using second-order nonlinear programming (NLP) methods. Moreover, the nonlinear constraints capturing transmission line losses make the electricity operational problem intractable if solved with mixed-integer NLP methods. Therefore, this work leverages the reliability and scalability of linear programming (LP) by designing two novel and distinct sequential LP (SLP) methods that exploit the particular structures of the two problems to find feasible, possibly optimal solutions, using only first-order information. The algorithmic framework is demonstrated on the IEEE 24-bus RTS connected to the 22-node Belgian gas network. This paper is the first to demonstrate H2 concentration tracking under transient gas flow in a multi-energy optimization framework on a realistic gas transmission network with multiple H2 injection locations.

Using mobile and fixed sensors for optimal monitoring of water distribution network under dynamic water quality simulations

Urban water distribution networks (WDNs) are strategic infrastructures, which have critical roles in preserving public health and social growth. This study designs a water quality monitoring network (WQMN) in the WDN Example 3 of EPANET2.0, contaminated with potassium cyanide (KCN), accounting for the dynamic changes of chlorine as a common water-quality parameter. The uncertainties in the contaminant events, such as the amount, location, start-time, and duration of contaminant injection, are considered in the problem formulations. A simulation-optimization framework based on EPANET-MSX and Particle Swarm Optimization algorithm is developed to determine the optimal location of the fixed sensor(s) and/or time and location of releasing mobile sensor(s). The results indicate that increasing the available mobile sensors from 1 unit to 3 or 5 units, decreased the contaminant detection time (DT) by 14% and 22%, increased the contaminant detection likelihood by 102% and 159%, and reduced the contaminated water consumption by 52% and 70%, respectively. The sensitivity analysis on the number of available sensors implies that changes in fixed sensors are more effective than mobile sensors on contaminant DT. The results showed the uncertainty in sink nodes' coverage area and mobile sensors’ battery life become more important as the number of mobile sensors increases.