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The present study aims to quantify the flow field, flow velocity, and heat transfer features over a horizontal flat plate under the influence of an applied magnetic field, with a particular emphasis on low Prandtl number fluids. Nonlinear partial differential expressions can be incorporated into the ordinary differential framework with the use of appropriate transformations. This research utilizes the variational iteration method (VIM) to approximate solutions for the system of nonlinear differential equations that define the problem. The objective is to demonstrate superior flexibility and broader application of the VIM in addressing heat transfer issues, compared to alternative approaches. The results obtained from the VIM are compared with numerical solutions, revealing a significant level of accuracy in the approximation. The numerical findings strongly suggest that the VIM is effective in providing precise numerical solutions for nonlinear differential equations. The analysis includes an examination of the flow field, velocity, and temperature distribution across various parameters. The study found that improving temperature patterns, velocity distribution, and flow dynamics were all positively impacted by increasing the Prandtl numbers. As a result, this leads to the thickness of the boundary layer to decrease and improves heat transfer at the moving surface. Thus, the convection process becomes more efficient. When the strength of the magnetic field is increased, the velocity of the fluid decreases. This observation aligns with expectations since the magnetic field hampers the natural flow of convection. Notably, the convection process can be precisely controlled by carefully applying magnetic force. [ABSTRACT FROM AUTHOR]

Technology automates a task that requires highly specialized and highly paid workers, enabling less-specialized or lower-paid workers to include that task in their workflow. HOW AI MIGHT REDUCE INEQUALITY When we look further into AI success stories of automation, it is often the case that tasks are automated in a way that is not skill biased, and indeed is the opposite: allowing more people to perform entire jobs at a level that previously required expensive skills. SPECIAL SECTION: A MACHINE-INTELLIGENT WORLD Impressive achievements made through artificial intelligence (AI) innovations in automating the tasks required in many jobs have reinforced concerns about labor market disruption and increased income inequality. However, many recent advances in AI that have been developed with the explicit goal of task automation have appeared to increase worker productivity; that is, task automation has been labor augmenting. [Extracted from the article]

Hypothyroidism may manifest as large ovarian cyst formation with precocious puberty in young pre-pubertal girls, which frequently regress upon starting thyroxin supplementation. We present a case report of a 10 year old girl who had undergone unnecessary laparoscopic cystectomy for bilateral large ovarian cyst as the diagnosis of hypothyroidism was missed. She again had recurrence of bilateral ovarian cyst which regressed upon thyroxin supplementation. [ABSTRACT FROM AUTHOR]

Three models to compute the refractive index of gaseous mixtures at real gas conditions are presented with the purpose to improve the accuracy of state relationships between refractive index and thermodynamic properties. Models are compared with experimental data to determine one that is applicable to high pressure mixtures with non-ideal thermodynamic behavior near or above a fluids' critical point. The optimal model is applied to analyze adiabatic thermal mixing of fuel and air at typical diesel engine conditions. Results show that the ideal gas mixture law is appropriate in the vapor region, assuming it is known, for example, from experimental measurements. Finally, the model is applied for binary fuel-air mixing at supercritical conditions to demonstrate its full potential. [ABSTRACT FROM AUTHOR]

Background: Vaginal cuff dehiscence is a rare but potentially grave complication after total hysterectomy. Abdominal or pelvic contents are at risk of evisceration through the vaginal opening. It is associated with significant risk for patient morbidity, such as peritonitis, bowel injury, and sepsis.Case Presentation: We report a case of vaginal cuff dehiscence in a 45-year-old multiparous Taiwanese woman who had undergone abdominal total hysterectomy and presented with vaginal cuff dehiscence precipitated by sexual intercourse. Immediate laparoscopic repair was done. Few authors have reported the utilization of the laparoscopic approach. It allows thorough inspection, visualization, and irrigation of the abdominal cavity. It is also associated with fewer intraoperative and postoperative complications.Conclusion: Laparoscopic repair is a safe treatment option to manage vaginal cuff dehiscence after total hysterectomy. [ABSTRACT FROM AUTHOR]

Lean premixed (LPM) combustion is very effective at mitigating emissions but is vulnerable to strong thermoacoustic instabilities. A porous insert in the shape of an annular ring placed at the dump plane of the combustor has been proven to be an effective passive technique for mitigating these instabilities across a wide range of operating conditions. However, it is unclear if the change results from the insert geometry or porosity of the insert. In this study, swirl-stabilized LPM combustion is investigated for three configurations--without any insert, with a porous insert, and with a geometrically similar solid insert. Acoustics, flow, and heat release rate behavior of the three test geometries are investigated using diagnostics including dynamic pressure and acoustic probes, particle image velocimetry (PIV), and OH* chemiluminescence (OH*CL) imaging. Synchronized measurements at a fixed equivalence ratio were acquired at 40 kHz using sound probes and at 3.5 kHz using PIV and OH*CL. Results include time-series and spectral measurements of pressure, velocity, and OH*CL, and mode analysis by proper orthogonal decomposition (POD). In addition, the dynamics of the instability are investigated by high-resolution phase reconstructions of velocity and OH*CL data using a novel implementation of POD introduced in this work. Results show two different instability modes: a longitudinal instability for the solid insert case and a helical, precessing vortex driven instability for the no insert case. In both cases, the flow field and heat release rate oscillations are coupled to produce the instability. No such coupling or oscillations is observed for the porous insert case. These results ascertain the unique capabilities of the porous insert in protecting against instability from different, simultaneous driving mechanisms and demonstrate that the insert porosity and flow dynamics associated with it are the primary mitigating factors. [ABSTRACT FROM AUTHOR]

Objective: Second uterine carcinosarcoma (UCS) occurs in <1% of patients after >5 years of treatment with concurrent chemoradiotherapy (CCRT) for cervical cancer. Surgical staging with lymphadenectomy is the mainstay of management that is largely done by the laparotomic approach. A Medline search for treatment of uterine carcinosarcoma after radiotherapy for cervical cancer was done using terms "uterine carcinosarcoma," "radiotherapy for cervical cancer," and "second primary uterine cancer," there is no case report or literature wherein UCS is treated by laparoscopy. Case Report: We present the first documented case of UCS diagnosed in a 72-year-old lady after 11 years of CCRT for cervical cancer stage 1B2, managed by laparoscopic staging wherein washing cytology, total hysterectomy, and bilateral salpingoophorectomy with pelvic and para-aortic lymphadenectomy were done. Conclusion: Minimal invasive surgical approach for surgical staging of irradiation-induced UCS may become a useful surgical option even in advanced stage in the era of minimally invasive surgery, offering advantages such as lower intraoperative blood loss, less need of transfusion, and shorter hospital stay with probably improved survival. [ABSTRACT FROM AUTHOR]

Background: Genitourinary tract actinomycosis is the second most frequent clinical form of actinomycosis. Although it has been recognized for over a century, owing of its infrequent and invasive nature, it often escapes proper diagnosis and mimics malignancy or tuberculosis. Case: This is a case of a uterine actinomycosis with extensive pelvic involvement that was preoperatively impressed as uterine adenomyosis but finally turned out to be a case of pelvic actinomycosis involving uterus, bilateral adnexae, sigmoid, and appendix. Results: Final histopathology revealed actinomycosis of sigmoid colon, endometrium, myometrium bilateral adnexae, and appendix. Conclusions: High index of suspicion and investigation to prove the diagnosis leads to optimum management of genital actinomycosis. (J GYNECOL SURG 36:214) [ABSTRACT FROM AUTHOR]

Background: A large percentage of cases of hysterectomy involves symptomatic myomas. It can be challenging to retrieve a large uterus after laparoscopic hysterectomy through the natural orifice of the vagina. Moreover, if there is a hard, calcified huge myoma, the task is even more difficult. Case: A 53-year-old gravida 4, para 3, female had a huge uterine myoma. Computed tomography scans showed a multilobulated heterogeneous uterine mass ∼13.8 × 9.8 × 11 cm with coarse calcifications at its mid and anterior aspects. Results: This patient underwent total laparoscopic hysterectomy with bilateral uterine-artery ligation, and a specimen was removed through her vagina. Manual morcellation was achieved, using 9 No.11 scalpels and a bone cutter. There were no intraoperative complications. This patient had an uneventful postoperative recovery. Her histopathology results were compatible with a leiomyoma. Conclusions: Vaginal morcellation of a uterus with a huge calcified myoma is feasible, using multiple scalpels and a bone cutter. This is the only case in cited in the literature in which a bone cutter was used to morcellate a uterus. [ABSTRACT FROM AUTHOR]

The effect of the chamber pressure on combustion of a twin-fluid-atomized spray of straight vegetable oil (VO) in a swirl stabilized combustion system is experimentally studied. A system with high pressure capabilities was developed, and flame and emissions characteristics of VO are investigated at elevated pressures up to about 5 bars, different heat release rates (HRRs), and atomizing air to liquid ratios (ALR) by mass. An image analysis technique was developed to infer flame and soot characteristics from visual images acquired by a digital camera. An increase in the ALR resulted in improved combustion of VO, characterized by blue flames, lower CO and NOx emissions, and minimal soot formation. For a given fuel flow rate, an increase in the chamber pressure resulted in smaller volume flames with lower CO levels but higher NOx emissions. Compared to diesel, as pressure increased, straight VO flames produced lower NOx and more voluminous flames characterized by distributed combustion with less soot formation. Overall, straight VO could be atomized and combusted at elevated pressures using the twin-fluid atomizer of the present study, and the resulting VO flames exhibited less sensitivity to chamber pressure variations. [ABSTRACT FROM AUTHOR]

More precise measurements of the fuel injection process can enable better combustion control and more accurate predictions resulting in a reduction of fuel consumption and toxic emissions. Many of the current methods researchers are using to investigate the transient liquid fuel sprays are limited by cross-sensitivity when studying regions with both liquid and vapor phases present (i.e., upstream of the liquid length). The quantitative rainbow schlieren technique has been demonstrated in the past for gaseous fuel jets and is being developed here to enable study of the spray near the injector. In this work, an optically accessible constant pressure flow rig (CPFR) and a modern common rail diesel injector are used to obtain high-speed images of vaporizing fuel sprays at elevated ambient temperatures and pressures. Quantitative results of full-field equivalence ratio measurements are presented as well as more traditional measurements such as vapor penetration and angle for a single condition (13 bar, 180 °C normal air) using n-heptane injected through a single hole (0.1mm diameter) common rail fuel injector at 1000 bar fuel injection pressure. This work serves as a proof of concept for the rainbow schlieren technique being applied to vaporizing fuel sprays, and full details of the imageprocessing routine are provided. The ability of the imaging technique combined with the constant pressure flow rig make this approach ideal for generating large data sets in short periods of time for a wide range of operating conditions. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a theoretical basis for scalability considerations and design of a large-scale combustor utilizing flow blurring (FB) atomization. FB atomization is a recently discovered twin-fluid atomization concept, reported to produce fine spray of liquids with wide range of viscosities. Previously, we have developed and investigated a small-scale swirl-stabilized combustor of 7-kWth capacity. Spray measurements have shown that the FB injector's atomization capability is superior when compared to other techniques, such as air blast atomization. However, despite these favorable results, scalability of the FB injector and associated combustor design has never been explored for large capacity; for example, for gas turbine applications. In this study, a number of dimensionless scaling parameters that affect the processes of atomization, fuel-air mixing, and combustion are analyzed, and scaling criteria for the different components of the combustion system are selected. Constant velocity criterion is used to scale key geometric components of the system. Scaling of the nonlinear dimensions and complex geometries, such as swirler vanes and internal parts of the injector is undertaken through phenomenological analysis of the flow processes associated with the scaled component. A scaled-up 60-kWth capacity combustor with FB injector is developed and investigated for combustion performance using diesel and vegetable oil (VO) (soybean oil) as fuels. Results show that the scaled-up injector's performance is comparable to the smaller scale system in terms of flame quality, emission levels, and static flame stability. Visual flame images at different atomizing air-to-liquid ratio by mass (ALR) show mainly blue flames, especially for ALR > 2.8. Emission measurements show a general trend of lower CO and NOx levels at higher ALRs, replicating the performance of the small-scale combustion system. Flame liftoff height at different ALRs is similar for both scales. The scaled-up combustor with FB injector preformed robustly with uncompromised stability for the range of firing rates (FRs) above 50% of the design capacity. Experimental results corroborate with the scaling methodology developed in this research. [ABSTRACT FROM AUTHOR]

Combustion noise and thermo-acoustic instabilities are of primary importance in highly critical applications such as rocket propulsion systems, power generation, and jet propulsion engines. Mechanisms for combustion instabilities are extremely complex because they often involve interactions among several different physical phenomena such as unsteady flame propagation leading to unsteady flow field, acoustic wave propagation, natural and forced hydrodynamic instabilities, etc. In the past, we have utilized porous inert media (PIM) to mitigate combustion noise and thermo-acoustic instabilities in both lean premixed (LPM) and lean direct injection (LDI) combustion systems. While these studies demonstrated the efficacy of the PIM concept to mitigate noise and thermoacoustic instabilities, the actual mechanisms involved have not been understood. The present study utilizes time-resolved particle image velocimetry (PIV) to measure the turbulent flow field in a nonreacting swirl-stabilized combustor without and with PIM. Although the flow field inside the annulus of the PIM cannot be observed, measurements immediately downstream of the PIM provide insight into the turbulent structures. Results are analyzed using the proper orthogonal decomposition (POD) method and show that the PIM alters the flow field in an advantageous manner by modifying the turbulence structures and eliminating the corner recirculation zones and precessing vortex core (PVC), which would ultimately affect the acoustic behavior in a favorable manner. [ABSTRACT FROM AUTHOR]

In the past, we have documented the efficacy of the ring-shaped porous inert media (PIM) to passively mitigate combustion noise and thermo-acoustic instabilities in lean premixed (LPM) swirl-stabilized combustion systems, although the underlying mechanisms involved have not been understood. The present study utilizes time-resolved particle image velocimetry (PIV) to measure the turbulent flow field in a LPM combustion system without and with PIM placed on the dump plane. Measurements of instantaneous and average flow fields, vorticity, and turbulent kinetic energy are presented to gain insight into the flow structure. Results are analyzed using the proper orthogonal decomposition (POD) to identify the effect of PIM on the coherent turbulent structures in the flow field. The addition of PIM removes the recirculation zones and the dominant coherent turbulent structures formed in the shear layers are convected downstream of the reaction zone. Harmonic reconstruction of the flow field is performed at the frequency of thermo-acoustic instability to identify the relationship between the flow and acoustic fields of the system. Without PIM, the vortical modes in the corner recirculation zone are shown to be the driving source for the instability. PIM alters the flow field from global instability to convective instability, which effectively eliminates the feedback mechanism for thermo-acoustic instabilities in the present LPM swirl-stabilized combustion system. [ABSTRACT FROM AUTHOR]

In this study, we present a fuel-flexible dual-fuel combustor to simultaneously burn methane and/or straight glycerol without preheating either glycerol or air by utilizing a novel flow-blurring (FB) liquid fuel injector. Product gas temperature, NO X and CO emissions at multiple locations inside the combustor are measured to quantitatively assess the flame structure, related to liquid atomization, droplet evaporation, and fuel–air mixing in the near field. For fixed total heat release rate, the impact of fuel mix on combustion performance is investigated by varying the methane gas and glycerol flow rates. For the same fuel mix, air to liquid mass ratio effect is evaluated by varying the atomizing air flow rate. Pure glycerol flame is also investigated to demonstrate the fuel flexibility and ease of switching between gas and liquid fuels in the present system. Results show that the methane combustion can assist glycerol vaporization to results in its rapid oxidation. In spite of the differences in the flame structure, profiles of product gas temperature and emissions at the combustor exit reveal that complete and mainly lean premixed combustion with low emissions is achieved for all of the test cases indicating excellent fuel flexibility of the present combustor using the FB injector. [ABSTRACT FROM AUTHOR]

This study demonstrates low-emission combustion of diesel, biodiesel and straight vegetable oil (VO) in a fuel-flexible combustor employing a flow blurring (FB) injector for fuel atomization. Measurements of gas temperature and CO and NOx concentrations at various axial and radial locations of the combustor are acquired using custom-designed thermocouple and gas sampling probes. Heat loss rate through the combustor is estimated from wall temperatures measured by an infra-red camera. A simple droplet model is used to predict fuel vaporization behavior in the dark-region near the injector exit. Results show that the FB injector produced clean blue flames indicating mainly premixed combustion for all three fuels. Matching profiles of heat loss rate and product gas temperature show that the combustion efficiency is fuel independent. NOx emissions for the three fuels agree with each other within the measurement uncertainties. CO emissions of straight VO are slightly higher than those for diesel and biodiesel. This difference in CO emissions is explained by the slower evaporation rate of straight VO droplets compared to diesel or biodiesel droplets. This study shows that with FB injector, straight VO without preheating or chemical pre-processing can be cleanly combusted in furnaces, boilers, or stationary power generation systems, thereby offering significant economical and environmental benefits. [ABSTRACT FROM AUTHOR]

Fuels produced from renewable sources offer an economically viable pathway to curtail emissions of greenhouse gases. Two such liquid fuels in common usage are biodiesel and ethanol derived from soybean, corn, or other food crops. In recent years, significant effort has been devoted to identify alternate feedstock sources and conversion techniques to diversify the biofuels portfolio. In this study, we have measured emissions from flames of diesel, biodiesel, emulsified bio-oil, and diesel-biodiesel blends. Experiments are conducted in an atmospheric pressure burner with an air-atomized injector and swirling primary air around it to replicate typical features of a gas turbine combustor. Experiments were conducted for fixed air and fuel flow rates, while the airflow split between the injector and the coflow swirler was varied. Results show a significant reduction in emissions as the fraction of total air fed into the atomizer is increased. Blue flames, reminiscent of premixed combustion, and low emissions of nitric oxides and carbon monoxide were observed for all fuel blends. In general, the emissions from biofuel flames were comparable or lower than those from diesel flames. [ABSTRACT FROM AUTHOR]

Abstract: Vortical structures formed in evolving jets are important in applications such as fuel injection in diesel engines and fuel leaks. When the jet fluid is different from the ambient fluid, the buoyancy can play an important role in determining the jet flow structure, and hence, the entrainment and fluid mixing processes. In the present study, a jet of helium injected in air is investigated, with emphasis placed on delineating the buoyancy effects on vector–scalar fields during the starting phase. We utilize a computational model, previously validated to predict the flow field of low-density gas jets. The model incorporates finite volume approach to solve the transport equation of helium mass fraction coupled with conservation equations of mixture mass and momentum. Computations were performed for a laminar jet to characterize the advancing jet front, and to capture the formation and propagation of vortex rings and the related pinch-off process. Results show significant effects of buoyancy on jet advancement, as well as on vorticity and helium concentration in the core of the vortex rings. [Copyright &y& Elsevier]

A counter-flow annular heat recirculating burner was designed for lean prevaporized; premixed combustion. Prior to entering the combustor, the reactants are passed through a porous media-filled preheating annulus surrounding the combustor. Kerosene is dripped by gravity onto the porous media and vaporized by the heat conducted through the combustor wall. Experiments were conducted to evaluate heat transfer and combustion performance at various equivalence ratios, heat release rates, and inlet air temperatures. Results show low CO emissions over a range of equivalence ratios. NOx emissions were high at high heat release rates, indicating inadequate prevaporization and premixing of fuel with air. Heat recirculation and heat loss characteristics are presented at various operating conditions. [ABSTRACT FROM AUTHOR]

Abstract: Combustion of kerosene inside porous inert medium (PIM) has been investigated with the goal of reducing the emissions of nitric oxides (NO x ), carbon monoxide (CO) and soot. Silicon-carbide (SiC) coated carbon foam is used as PIM to attain high structural strength. The two-zone porous burner design consists of preheat and combustion sections. Different PIM configurations were tested by stacking together square porous pieces of 2.5cm thickness. Two types of fuel injectors are considered: (i) in the air-assist injector, approximately 5% of the combustion air is used for atomization and the remaining air enters as the primary co-flow around the injector, and (ii) in the swirling-air injector, all of the combustion air enters the injector to create a swirling flow around the fuel jet to enhance atomization and fuel–air premixing. The distance between the injector and PIM inlet is a key operational parameter, which was varied in experiments with both injectors over a range of equivalence ratios and heat release rates. The NO x and CO emissions were measured to optimize the PIM configuration with minimum emissions. Results show stable combustion over a wide operating range. Three combustor operational regimes are identified depending upon the injector location. [Copyright &y& Elsevier]

Acute Fatty Liver of Pregnancy (AFLP) is a rare but catastrophic disease affecting women in pregnancy. It usually occurs in the third trimester or post-partum period. Delay in diagnosis is associated with morbid complications with high morbidity and mortality. We report a case of 24 years old female at 38 weeks period of gestation who presented with jaundice, vomiting for 3 days and deranged liver function test. She was diagnosed as acute fatty liver of pregnancy and was delivered by instrumental delivery but required cesarean hysterectomy due to postpartum hemorrhage. She started improving with supportive care and discharged after 4 weeks of hospital stay. [ABSTRACT FROM AUTHOR]

Abstract: Flow structure of helium jets injected into quiescent air was investigated numerically using finite volume approach. The analysis is based on unsteady, laminar, axisymmetric, isothermal flow in a binary fluid system. The jet Reynolds number, Re was varied from 40 to 150 to encompass steady and oscillating jet flow regimes. Comparison with experimental data revealed excellent agreement, proving reliability of the model in predicting global flow characteristics. At low jet Reynolds numbers, the flow was steady and the concentration shear layer at the tube exit was stratified by mixing between jet and ambient fluids inside the tube. At higher jet Reynolds numbers (Re =90 and 150), buoyancy induced acceleration contracted the jet core to form a toroidal vortex by entrainment of the ambient fluid. Structural details of the globally unstable flow are discussed using instantaneous, mean and RMS profiles of helium concentration and axial velocity. [Copyright &y& Elsevier]

A low-density gas jet injected into a high-density ambient gas is known to exhibit self-excited global oscillations accompanied by large vortical structures interacting with the flow field. In this study, the formation and evolution of vortices and scalar structure of the flow field are investigated in buoyant helium jets discharged from a vertical tube into quiescent air. This is accomplished by applying the quantitative rainbow schlieren deflectometry technique to optically measure the local helium mole percentage across the whole field. Data were acquired over downstream locations extending from tube exit to about 3.0d (d=31.8 or 19.1 mm is the jet tube inside diameter) at spatial resolution of 0.14 mm and temporal resolution of 16.7 ms. Oscillations at identical frequency were observed throughout the flow field. The evolving flow structure is described by helium mole percentage contours during an oscillation cycle. Instantaneous, mean, and rms concentration profiles are presented to describe interactions of the vortex with the jet flow. Oscillations in a narrow wake region near the jet exit are shown to spread through the jet core near the downstream location of the vortex formation. The effects of jet Richardson number on characteristics of vortex and flow field are investigated and discussed. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Experiments were conducted in Earth gravity and microgravity to acquire quantitative data on near-field flow structure of helium jets injected into air. Microgravity conditions were simulated in the 2.2-s drop tower at NASA John H. Glenn Research Center. The jet flow was observed by quantitative rainbow schlieren deflectometry, a nonintrusive line-of-sight measurement technique suited for the microgravity environment. The flow structure was characterized by distributions of helium mole fraction obtained from color schlieren images taken at 60 Hz. Results show that the jet in microgravity was up to 70% wider than that in Earth gravity. Experiments reveal that the global flow oscillations observed in Earth gravity are absent in microgravity. Quantitative details are provided of flow evolution as the experiment undergoes change in gravity in the drop tower. [ABSTRACT FROM AUTHOR]

Chemotherapeutic efficacy of the amphotericin B (Amp B), which is the drug of choice for treatment of the leishmanial infections (kala-azar) that become resistant to the conventional chemotherapy using antimonials, has been examined in the Leishmania donovani infected hamsters after encapsulating the drug in tuftsin-free as well as tuftsin-bearing liposomes. The activity was significantly increased ( p <0.05) by delivering Amp B in tuftsin-free liposomes. This antileishmanial effect of the liposomized Amp B was further increased ( p <0.05) by grafting the natural macrophage-activator tetrapeptide, tuftsin (Thr-Lys-Pro-Arg), on the liposome's surface. This could possibly be attributed to both the enhanced drug tolerance after liposomization as well as to the increased uptake of tuftsin-bearing Amp B-laden liposomes by the macrophages. In addition to the increased efficacy, encapsulation of Amp B in the tuftsin-bearing liposomes also enhanced the drug accessibility to areas (e.g. bone marrow) that are otherwise inaccessible to the free drug. These results further demonstrate the usefulness of tuftsin-bearing liposomes as drug vehicles in treatment of the macrophage-based infections that have been reviewed recently (Agrawal, A.K. and Gupta, C.M. (2000). Tuftsin-bearing liposomes in treatment of macrophage-based infections, Adv. Drug Deliv. Rev. , 41, 135-146). [ABSTRACT FROM AUTHOR]

• We introduce Peripheral Fuel Injection (PeFI) using multiple injectors to replace Conventional diesel combustion (CDC). • In this study, detailed 3D CFD of reacting flow is used to compare thermal and thermodynamic performance of CDC and PeFI. • PeFI is shown to eliminate detrimental jet-wall and jet-to-jet interactions. • PeFI reduces heat loss to the chamber wall by up to 5 percentage points as compared to CDC. • PeFI allows faster heat release rate and provides greater access to ambient air during the non-premixed combustion mode. • PeFI benefits are expected to increase when differences in the ROI profiles for CDC and PeFI are taken into consideration. A centrally located multi-hole injector supplying fuel towards the chamber wall is the most common fuel injection strategy for conventional diesel combustion (CDC) today. CDC strategy is prone to flame-wall and liquid-wall interactions with adverse effects on heat transfer, combustion and emissions performance. In the present study, peripheral fuel injection (PeFI) supplying fuel inwards from the chamber wall using multiple single-hole injectors is explored to achieve higher performance. The two methods of fuel injection are compared numerically in a constant volume combustion chamber. Simulations use n-dodecane with the same rate of injection profile for both injection schemes to obtain a conservative estimate of differences. Six configurations are trialed including a six-hole central injector and six, single-hole peripheral injectors with layout angles of θ = 0, 15, 22.5, 30 and 37.5 degrees relative to the radius of the chamber. Quantitative analysis shows that a properly configured PeFI eliminates flame-wall interactions, reduces heat loss, and improves heat release rate when compared to an equivalent CDC system. PeFI could also provide thermal efficiency and emissions benefits although these were not addressed explicitly in the present work. [ABSTRACT FROM AUTHOR]

Presents information on a study that described an application of the rainbow schlieren deflectometry (RSD) technique to evaluate computational fluid dynamics (CFD) calculations of nonreacting and reacting flows. Assumed calculations; Outline of RSD; Details on the CFD analysis; Results in comparing predictions with the measurements.

In this study, convergent nozzles of various area ratios (ARs) are used downstream of an annular rotating detonation combustor (RDC) to increase the operating pressure and approach sonic conditions at the nozzle throat. Reactant methane and oxygen-enriched air (67% O2 and 33% N2 by volume) are supplied in counterflow arrangement from two separate plenums located at the base of the RDC annulus. Based on experimentation, a total mass flow rate of 0.32 kg/s was chosen to achieve stable, single-wave mode RDC operation for all test cases, allowing for one-to-one comparisons. The internal performance of the RDC was characterized by ion probes and pressure measurements (wall static and oscillating) in supply plenums and across different axial locations of the combustor. Particle image velocimetry (PIV) at 100 kHz was utilized to measure axial and circumferential velocity components within a two-dimensional region of interest located downstream of the converging nozzle exit. Results show higher internal performance of the RDC with increasing AR of the convergent nozzle. PIV measurement illustrated that the flow oscillation amplitudes decrease with an increasing AR of the converging nozzle. The exit flow contained significant nonuniformity and unsteadiness even with a converging nozzle of AR 2.0, indicating incomplete choking of the flow at the nozzle throat. [ABSTRACT FROM AUTHOR]

Transient, near-field mixing of a supercritical fluid injected into supercritical and subcritical environments is investigated experimentally. Fuel (propane) from a 100 μm diameter Bosch diesel injector is injected into a high-pressure test rig with a steady flow of heated, low-velocity nitrogen to control the ambient pressure and temperature. The fuel supply pressure is approximately 190 bar, allowing short injections lasting 3–4 ms to be performed in quick succession to acquire statistically significant datasets to represent the unsteady fuel–air mixing. Two test cases with the same ambient density and injector inlet pressure and temperature were chosen in an attempt to isolate effects of mixture phase behavior. Microscopic rainbow Schlieren deflectometry (RSD) is used for visualization and quantitative data acquisition. In the case of the supercritical ambient, the injector inlet and exit and ambient conditions are all supercritical. The RSD analysis reveals a mixing process similar to the single phase fluid mixing, though condensation is also observed locally, and can be explained by the adiabatic mixing theory presented in the paper. For the subcritical ambient case, the injector inlet is supercritical, but the injector exit and ambient conditions are both subcritical. The results show a rapid expansion in the near-field promoting mixing between propane and nitrogen. At downstream locations, significant condensation is also observed as predicted by the adiabatic mixing theory. The supercritical ambient case exhibited longer and narrower jet penetration compared to the subcritical ambient case. [ABSTRACT FROM AUTHOR]

Background: The maternal mortality ratio is a significant public health indicator that reflects the quality of health care services. The prevalence is still high in developing countries than in the developed countries. This study aimed to determine the MMR and identify the various risk factors and causes of maternal mortality.Methods: This is a retrospective study conducted in a tertiary care center in Eastern Nepal from 16th July 2015 to 15th July 2020. The maternal mortality ratio was calculated per 100,000 live-births over five year's study period. The causes of death, delays of maternal mortality and, different sociodemographic profiles were analyzed using descriptive statistics.Results: There was a total of 55,667 deliveries conducted during the study period. The calculated maternal mortality ratio is 129.34 per 100,000 live-births in the year 2015 to 2020. The mean age and gestational age of women with maternal deaths were 24.69 ± 5.99 years and 36.15 ± 4.38 weeks of gestation. Obstetric hemorrhage, hypertensive disorder of pregnancy and sepsis were the leading causes of maternal death. The prime contributory factors were delay in seeking health care and reaching health care facility (type I delay:40.9%).Conclusions: Despite the availability of comprehensive emergency obstetric care at our center, maternal mortality is still high and almost 75% of deaths were avoidable. The leading contributory factors of maternal mortality are delay in seeking care and delayed referral from other health facilities. The avoidable causes of maternal mortality are preventable through combined safe motherhood strategies, prompt referral, active management of labor and, puerperium. [ABSTRACT FROM AUTHOR]

Introduction: During global Covid-19 pandemic, India fought against the situation by implementing strict lockdown in whole country starting from 25th March 2020. Looking at severity of situation government decided to extend it in 4 phases till 31st May, 2020 which has been applied strictly in all district belonging to "Red Zone". Agra is the worst hit district in Uttar-Pradesh and it remained in the condition of strict Lockdown. Materials and Methods: Record-based comparative cross-sectional study looking for the impact of lockdown on change in pattern and number of medico-legal cases in Agra was done. Data related to name, age, sex, place of residence, type of medico-legal case was collected from records of medicolegal cases admitted in Emergency department of S.N. Medical College, Agra for the period of 25th March to 31 May 2020 (lockdown period) and compared it with data collected from 25th March to 31st May 2019 i.e. data of same corresponding period in last year. Results: On comparison we found out that during lockdown there was a decrease in no. of total admissions by 37.7%, while no. of medico legal cases is decreased by 54.2%. On further analysis of the data maximum decrease is seen in cases of road traffic accident, burns and firearm injuries while there was an increase in number of MLC cases of hanging. On gender wise comparison it was found that during lockdown period male MLC patients are decreased by 62.9% while female MLC patients decreased by 23.5%, which is lesser than decrease in total no. of admission. Interestingly we found out that there is increase in no. of MLC cases of female poisoning and hanging also increased significantly which might be due to increased domestic unrest or financial crisis emerged due to lockdown. Although on comparison of age groups no significant difference is seen during lockdown period. On area-wise comparison there was a decrease from 33% to 18% in total no. of MLC cases coming from districts other than Agra. This may be due to affected referral service or restrictions in inter-district transport. Conclusions: There is overall decrease in medico-legal cases with increased cases of hanging. Cases of female poisoning is also increased probably due to undue raised burden caused due to lockdown. [ABSTRACT FROM AUTHOR]

Rotating detonation combustors (RDCs) have gained increased interest for integration with power-generating gas turbines due to the potential to increase thermal efficiency. The unsteady flow field exiting the RDC is fundamentally different compared to traditional swirl-stabilized combustors. Successful integration of RDC with gas turbines will depend on the ability to properly condition the unsteady flow to achieve performance levels comparable to swirl-stabilized combustors. RDC simulations require significant computational resources due to the small spatial and temporal time scales required to resolve the detonation phenomenon. Furthermore, traditional steady-state computational fluid dynamics (CFD) analyses are not possible for RDC simulations. The present study develops and validates a computationally efficient approach for predicting unsteady flow fields exiting the combustor using 2D, transient reacting CFD with periodic boundary conditions in the combustor and a downstream plenum. Validation is performed by comparing the CFD results to various experimental measurements: (i) wave speed obtained from high-speed ion probe and dynamic pressure data, (ii) average wall static pressure measurements, and (iii) time-resolved particle image velocimetry (PIV) at 100 kHz at the RDC exit. Results indicate good agreement between CFD and experiments with respect to velocity field exiting the RDC, detonation wave speed, and static pressure distribution. [ABSTRACT FROM AUTHOR]

The present study aims to experimentally characterize the performance of a rotating detonation combustion (RDC) system integrated with a pressurized downstream plenum to simulate the high-pressure inlet conditions of power-generating gas turbines. A thorough understanding of the operational behavior including wave mode behavior, static pressure profile along the combustor length, and dynamic features of pressure fluctuations is crucial for successful integration of RDC with the turbine. In this study, two RDC configurations are investigated, RDC with a constant area annulus and RDC with a converging nozzle. In both cases, the RDC flow exited into a plenum chamber kept at pressures varying from 155 kPa to 330 kPa. RDC was operated on methane and oxygen-enriched air to represent reactants used in land-based power generation. Experiments were conducted for the two RDCs configurations operated at three reactant mass flow rates (0.23, 0.32, and 0.46 kg/s). The RDC performance is characterized by time-averaged static pressure measurements, and wave velocity determined by ionization probes. In addition, dynamic pressure measurements were recorded both inside and near the exit of RDC channel to investigate wave interactions between RDC and downstream plenum. Results show that the RDC with the converging nozzle achieved superior performance while minimizing detrimental interactions with the reflected shock and/or acoustic waves from the downstream plenum. [ABSTRACT FROM AUTHOR]

Rainbow schlieren deflectometry (RSD) is applied to acquire quantitative concentration measurements in a turbulent environment for the first time. RSD methodology is developed and validated using Rayleigh scattering data available in the literature. Experiments were performed in an initially laminar, momentum-driven helium jet injected into ambient air. Full-field measurements are acquired that span the laminar, transition, and fully turbulent regions of the jet. The RSD results are shown to provide accurate measurements in each region and also confirm the self-similar nature of the fully turbulent jet. Analysis shows that the transition from laminar to turbulent flow occurs across an axial span that decreases with increasing Reynolds number. Experiments with a long exposure time were conducted to evaluate the limitations of hardware averaging of the RSD signal in comparison with software averaging. [ABSTRACT FROM AUTHOR]

A robust methodology to develop phase diagrams of binary fluid mixtures at fixed thermodynamic conditions (pressure, temperature, and mole fraction) as well as of two initially separated fluids undergoing mixing near critical conditions are presented for fluids and conditions relevant to rockets, gas turbines, and diesel engine applications. Phase equilibria of mixtures are first examined to provide insight into the continuous-phase mixing behavior (including but not limited to supercritical behavior), and to develop a broadly applicable phase-diagram for binary fluid mixtures at fixed conditions. Next, adiabatic mixing theory and reduced Helmholtz equations of state are used to predict the thermodynamic conditions required to attain continuous-phase binary fluid mixing near critical conditions. Then, a 3D surface diagram (P , T f u e l , T a m b) separating single and two-phase regions is constructed by varying the ambient pressure and the initial temperatures of the two fluids. Polynomial fits of the 3D surfaces for 10 different binary mixtures are tabulated for nitrogen–alkane and methane–oxygen blends relevant to air-breathing and propellant based engines, respectively. • Binary fluid mixture phase diagram is introduced for set thermodynamic conditions • A new phase diagram (3D surface) is developed for binary fluid mixing • Fluid mixing behavior is quantified based solely on inlet conditions • Tabulated polynomials are provided for the 10 different binary mixture phase diagrams [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding of the structure of complex supersonic flows requires high-resolution, nonintrusive measurements across the whole field. The measurement requirements are even more challenging when dealing with small-scale systems. In this study, we apply the miniature rainbow schlieren deflectometry system to measure the density field in underexpanded microjets from an orifice injector of 500 μm diameter. The injector is used to replicate the practical scenario of accidental leakage from a compressed gas storage facility. Experiments were conducted for a range of supply pressures Ps, although the majority of the results are presented for Ps = 860 kPa. Experimental schlieren images were analyzed to determine the density contours in an axisymmetric domain with a field of view of 1.5 mm radius and 7.5 mm length, at a spatial resolution of 25 μm. Pressure, temperature, and Mach number profiles (normalized by the values at the orifice) were also obtained along the jet centerline. Results show features similar to those observed in underexpanded macrojet from a sonic nozzle; multiple shock-cell structures with expansion and compression fans, freejet boundary, incident, normal, and reflected shock waves, subsonic slip strip, and outer shear layer. The miniature rainbow schlieren deflectometry technique is shown to provide high-quality quantitative data to explain the structural details of underexpanded microjets. [ABSTRACT FROM AUTHOR]

This study deals with the computational analysis of the near-field flow structure in an isothermal helium jet injected into quiescent ambient air environment. Laminar, axisymmetric, and unsteady flow conditions were considered for the analysis. The transport equations of helium mass fraction coupled with the conservation equations of mixture mass and momentum were solved using a staggered grid finite-volume method. Jet Richardson numbers encompassing both buoyant and inertial jet flow regimes were considered. Buoyancy effects were isolated by initiating computations in Earth gravity and subsequently, reducing the gravity to simulate microgravity conditions in the 2.2 s drop tower. Computed results concur with experimental observations, i.e., a self-excited buoyant jet with periodic flow oscillations in Earth gravity becomes steady in microgravity. In an inertial jet, the flow oscillations occur at the same frequency regardless of the buoyancy, although the oscillation amplitude decreases in microgravity. [ABSTRACT FROM AUTHOR]

The detonation wave(s) in a rotating detonation combustor (RDC) produce highly unsteady flow with varying supersonic and subsonic segments. The non-homogeneous RDC flow must be conditioned to improve its uniformity, which can increase the performance and operation of the downstream hardware for propulsion and power generation applications. In this study, the RDC channel and converging nozzle are combined into a single flow conditioning device, and Gradual to rapid (GTR), Linear, and Rapid to Gradual (RTG) strategies to profile the cross-sectional area of the combined channel are introduced. An inward flowing disk-RDC (D-RDC) operated on gaseous methane-oxygen is numerically investigated using a quasi-two-dimensional computational fluid dynamic (CFD) simulation with a curvilinear coordinate system. The study focuses on the combined channel to isolate the effects of area profiling and neglects radial to axial turning of the flow necessary to integrate it, for example, with an aerospike nozzle located downstream. Simulations show that the RTG area profile yields a higher performance compared to GTR and Linear cases. The RTG profile is also shown to improve pressure and temperature uniformity of the RDC flow at the throat. Results are analyzed to show that a rapid decrease in the cross-sectional area closer to the detonation for the RTG profile improves the stability of the detonation process and constrains the expansion of product gases behind detonation to orient the flow radially inwards. Therefore, profiling the cross-sectional area of an RDC can be vital in improving the operability and effective integration of the downstream hardware. [ABSTRACT FROM AUTHOR]

In this study, a porous insert is placed at the dump plane of a swirl-stabilized lean premixed combustor to passively suppress thermoacoustic instabilities. The diffuser-shaped annular ring of porous inert material influences the turbulent flow field directly, including recirculation zones and vortical and/or shear layer structures to passively control the acoustic performance of the combustor. The porous inert material is made of silicon carbide-hafnium carbide coated, high-strength, high-temperature-resistant open-cell foam materials. In this study, the porous insert concept is investigated at above-ambient operating pressures to demonstrate its suitability for practical combustion applications. Experiments are conducted in quartz and metal combustors, without and with the porous insert while varying operating pressure, equivalence ratio, and reactant flow rate. Measurements show that the porous insert, and consequent changes in the combustor flow field, decrease the sound pressure levels at the frequency of combustion instability at all operating conditions investigated in this study. The porous insert also decreases the broadband combustion noise, i.e. the measured sound pressure levels over a wide frequency range. [ABSTRACT FROM AUTHOR]

This study examines the incidence of false-positive results in a sample of rapid antigen tests used to serially screen asymptomatic workers throughout Canada. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding a study which examines the life sciences venture capital (VC) activity in emerging markets conducted from January 2000 to August 2012.

Recent increases in fuel costs, concerns for global warming, and limited supplies of fossil fuels have prompted wide spread research on renewable liquid biofuels produced domestically from agricultural feedstock. In this study, two types of biodiesels and vegetable oil (VO) are investigated as potential fuels for gas turbines to generate power. Biodiesels produced from VO and animal fat were considered in this study. The problems of high viscosity and poor volatility of VO (soybean oil) were addressed by using diesel-VO blends with up to 30% VO by volume. Gas chromatography/mass spectrometry, thermogravimetric analysis, and density, kinematic viscosity, surface tension, and water content measurements were used to characterize the fuel properties. The combustion performance of different fuels was compared experimentally in an atmospheric pressure burner with an air-assist injector and swirling primary air around it. For different fuels, the effect of the atomizing airflow rate on Sauter mean diameter was determined from a correlation for air-assist atomizers. Profiles of nitric oxides (NOx) and carbon monoxide (CO) emissions were obtained for different atomizing airflow rates, while the total airflow rate was kept constant. The results show that despite the compositional differences, the physical properties and emissions of the two biodiesel fuels are similar. Diesel-VO fuel blends resulted in slightly higher CO emissions compared with diesel, while the NOx emissions correlated well with the flame temperature. The results show that the CO and NOx emissions are determined mainly by fuel atomization and fuel/air mixing processes, and that the fuel composition effects are of secondary importance for fuels and operating conditions of the present study. [ABSTRACT FROM AUTHOR]

In support of efforts to develop improved models of turbulent spray behavior and combustion in diesel engines, experimental data and analysis must be obtained for guidance and validation. For Reynolds-averaged Navier-Stokes (RANS)-based Computational fluid dynamics (CFD) modeling approaches, representative ensemble average experimental results are important. For high-fidelity models such as large eddy simulations (LES)-based CFD, precise individual experimental results are desirable. However, making comparisons between a given experiment and LES is a challenge since local parameters cannot be directly compared. In this work, an optically accessible constant pressure flow rig (CPFR) is utilized to acquire diesel-like fuel injection and reaction behavior simultaneously with three optical diagnostic techniques: rainbow Schlieren deflectometry (RSD), OH* chemiluminescence (OH*), and two-color pyrometry (2CP). The CPFR allows a large number of repeated injection experiments to be performed for statistical analysis and convergence using ensemble-averaging techniques, while maintaining highly repeatable test conditions. Even for stable test conditions, variations in local turbulent fuel-air mixing introduce variability, which manifests as significant differences in OH* and 2CP results. Experimental measurements of characteristic parameters including liquid and vapor jet penetration, liftoff length, soot temperature and concentration, and turbulent flame speed, along with the shot-to-shot variability of each dataset, are presented and discussed. A statistical method is utilized to analyze the extent of this variability, and to identify superlative injections within the dataset for discussion and analysis of shot-to-shot variations. [ABSTRACT FROM AUTHOR]

Previous studies of diesel spray flames have focused on details of the sooting behavior mainly during the quasi-steady period, but few have considered the spatially-resolved transient evolution in combination with injection-to-injection variations. In this study, a 500-injection data set is utilized to investigate the temporal evolution of a spray flame during auto-ignition, the premixed burn phase, and the quasi-steady period. Spatially-resolved OH* chemiluminescence data provide ignition delay times and reaction zone locations. Two-color pyrometry with a vastly improved optical system is used to quantify spatially-resolved soot evolution and its statistical variations. The ambient thermodynamic conditions are slightly below those in modern diesel engines, resulting in longer lift-off lengths and lower overall soot production. Spatially, soot formation in the lift-off region is small, but appreciable soot forms in the jet core and jet head regions, while it oxidizes gradually on the jet periphery. Total soot mass profiles indicate that regions with larger local soot mass take longer to form, but are the first to oxidize. Probability distributions of soot mass in localized regions indicate that a few injections with high soot mass bias the average soot mass data towards higher values. Overall, results show good agreement with previous studies employing different diagnostic techniques while providing statistical details of transient and localized soot behavior in high pressure diesel spray flames in support of the related modeling efforts. Novelty and Significance Statement This work utilizes a newly developed two-color pyrometry system to study spatially-resolved transient evolution of soot in high-pressure diesel-like fuel sprays. Soot size distributions and probability distributions are analyzed in localized regions of the reacting jet. Discussions of soot formation, transport, and oxidation align with others work in the literature while offering new quantitative insights. The large dataset of 500 repeated injections can be leveraged by the modelers to predict the range of behavior expected under otherwise stable conditions. [ABSTRACT FROM AUTHOR]

Pressure gain combustion (PGC) has been conceived to convert fuel's chemical energy into thermal energy and mechanical energy, thereby reducing the entropy production in the process. Recent research has shown that the rotating detonation combustor (RDC) can provide excellent specific thrust, specific impulse, and pressure gain within a small volume through rapid energy release by continuous detonation in the circumferential direction. The RDC as a PGC system for power generating gas turbines in combined cycle power plants could provide significant efficiency gains. However, few past studies have employed fuels that are relevant to power generation turbines, since RDC research has focused mainly on propulsion applications. In this study, we present experimental results from RDC operated on methane and oxygen-enriched air to represent reactants used in land-based power generation. The RDC is operated at a high pressure by placing a back-pressure plate downstream of the annular combustor. Past studies have focused mainly on probe measurements inside the combustor, and thus, little information is known about the nature of the products exiting the RDC. In particular, it is unknown if chemical reactions persist outside the RDC annulus, especially if methane is used as the fuel. In this study, we apply two time-resolved optical techniques to simultaneously image the RDC products at framing rate of 30 kHz: (1) direct visual-imaging to identify the overall size and extent of the plume, and (2) OH* chemiluminescence imaging to detect the reaction zones if any. Results show dynamic features of the combustion products that are consistent with the probe measurements inside the rotating detonation engine (RDE). Moreover, presence of OH* in the products suggests that the oblique shock wave and reactions persist downstream of the detonation zone in the RDC. [ABSTRACT FROM AUTHOR]

Fundamental understanding of in-cylinder processes in diesel engines is important to screen emerging biofuels and advanced combustion modes that can reduce greenhouse gas emissions and regulated pollutants including soot. In this study, the role of fuel properties on spray development and combustion is investigated by systematically isolating chemical and thermophysical effects. Three different fuels are considered, two with similar chemical properties and two with similar thermophysical properties with one fuel common to both groups. Experiments are performed in a constant-pressure flow chamber designed to provide stable test conditions and facilitate acquisition of at least 150 injections in quick succession for each fuel under reacting high-pressure, high-temperature ambient conditions using a modified conventional diesel engine injector. High speed optical diagnostics including rainbow schlieren deflectometry, OH* chemiluminescence, and a two-color pyrometry system are employed to simultaneously image the transient spray and reacting jets. Image analysis is performed to determine liquid length, vapor penetration length, timing and location of first stage and main ignition events, lift-off location, total soot mass, and more. Results show that fuels with similar chemical properties or cetane number (CN) exhibit similar delay times for first stage and main ignition events as may be expected, but very different liquid length, first stage and main ignition locations, lift-off length, apparent turbulent flame speed, and soot formation. As such, the ability to characterize candidate biofuels with CN or other parameters derived from simple flame configurations is called into question. In this study, thermophysical properties controlling the liquid length are identified as the main contributing factor for the observed differences. [ABSTRACT FROM AUTHOR]