Temperature and reaction zone imaging in turbulent swirling dual-fuel flames

Gaseous and liquid dual-fuel flames present both a practical approach to emissions reduction and a challenge to current state-of-the-art combustion modelling. This paper uses simultaneously imaged temperature and normalised OH signal fields to investigate flame structure and provide experimental data for model validation across a range of swirl-stabilised n-heptane spray flames. These data are obtained by non-linear excitation regime two-line atomic fluorescence (NTLAF) of indium, and planar laser-induced fluorescence (OH-PLIF), respectively. Swirling gas streams are varied by flowrate (63–88% of blow-off), premixed equivalence ratio (including air-only), and by type of gaseous fuel (natural gas and hydrogen). Results are used to describe how hot combustion products interact with the fuel spray: heating and diluting the region above the apex of the spray cone at low air flowrates but drawing fuel into outer branches of the flame with increasing air flowrates. Adding natural gas to the swirling air stream, at a concentration below the lean flammability limit, gives rise to a temperature increase in the outer branches with little effect on the hot region above the apex of the spray, along the burner centreline. The size of this region is significantly reduced; however, using hydrogen. As the concentration of gaseous fuel increases towards the lean flammability limit, peak temperatures shift towards the outer branch of the flame. Exceeding the lean flammability limit, an additional reaction zone begins to form in the premixed swirling stream, adjacent to the outer branch of the swirl flame. Stable outer branches of the swirl flame, however, become less prevalent and the peak temperatures of the spray flame return to burner centreline. This study provides insight into the complex behaviour of dual-fuel flames, a complementary dataset to related, PLIF-only studies and validation data for the development of numerical modelling tools.M.J.Evans, J.A.M.Sidey, J.Ye, P.R.Medwell, B.B.Dally, E.Mastorako

Fundamental Aspects of Jet Ignition for Natural Gas Engines

© 2017 SAE International. Large-bore natural gas engines may use pre-chamber ignition. Despite extensive research in engine environments, the exact nature of the jet, as it exits the pre-chamber orifice, is not thoroughly understood and this leads to uncertainty in the design of such systems. In this work, a specially-designed rig comprising a quartz pre-chamber fit with an orifice and a turbulent flowing mixture outside the pre-chamber was used to study the pre-chamber flame, the jet, and the subsequent premixed flame initiation mechanism by OH* and CH* chemiluminescence. Ethylene and methane were used. The experimental results are supplemented by LES and 0D modelling, providing insights into the mass flow rate evolution at the orifice and into the nature of the fluid there. Both LES and experiment suggest that for large orifice diameters, the flow that exits the orifice is composed of a column of hot products surrounded by an annulus of unburnt pre-chamber fluid. At the interface between these layers, a cylindrical reaction zone is formed that propagates in the main chamber in the axial direction assisted by convection in the jet, but with limited propagation in the cross-stream direction. For small orifice diameters, this cylinder is too thin, and the stretch rates are too high, for a vigorous reaction zone to escape the pre-chamber, making the subsequent ignition more difficult. The methane jet flame is much weaker than the one from ethylene, consistent with the lower flame speed of methane that suggests curvature-induced quenching at the nozzle and by turbulent stretch further downstream. The velocity of the jet is too high for the ambient turbulence to influence the jet, although the latter will affect the probability of initiating the main premixed flame. The experimental and modelling results are consistent with ongoing Direct Numerical Simulations at ETH Zurich

Intensity of Resistance Exercise Determines Adipokine and Resting Energy Expenditure Responses in Overweight Elderly Individuals

OBJECTIVE - To evaluate the time course of leptin, adiponectin, and testing energy expenditure (REE) responses in overweight elderly mates after acute resistance exercise protocols of various intensity configurations. RESEARCH DESIGN AND METHODS - Forty inactive men (65-82 years) were randomly assigned to one of four groups (n = 10/group): control, low-intensity resistance exercise, moderate-intensity resistance exercise, and high-intensity resistance exercise. Exercise energy cost, REE, leptin, adiponectin, cortisol, insulin, lactate, glucose, nonesterified fatty acids (NEFAs), and glycerol were determined at baseline, immediately after exercise, and during a 72-h recovery period. RESULTS - Exercise energy cost was lower in high-intensity than in low-intensity and moderate-intensity groups (221.6 +/- 8.8 vs. 295.6 +/- 10.7 and 281.6 +/- 9.8 kcal, P < 0.001). Lactate, glucose, NEFAs, and glycerol concentrations increased (P < 0.001) after exercise and returned to baseline thereafter in all groups. REE increased (P < 0.001) in all groups at 12 h in an intensity-dependent manner (P < 0.05). REE reached baseline after 48 h in the low- and mode rate-intensity groups and after 72 h in the high-intensity group. Cortisol peaked in all active groups after exercise (P < 0.001) and remained elevated (P < 0.001) for 12 h. After adjustment for plasma volume shifts, leptin remained unaltered. Adiponectin concentration increased after 12 hand remained elevated for 24 h only in the high-intensity group (P < 0.001). CONCLUSIONS - Resistance exercise does not alter circulating leptin concentration but does increase REE and adiponectin in an intensity-dependent manner for as long as 48 and 24 h, respectively, in overweight elderly individuals. It appears that resistance exercise may represent an effective approach for weight management and metabolic control in overweight elderly individuals

A comparative study on the effect of simulated EGR environment on spray characteristics under engine-like conditions

Abstract Increasing concern over air quality and security of energy supply poses challenges to engine research and manufacturing. Despite improvements in conventional engine design, many alternatives are winning their place in order to further reduce engine-out emissions. Sophisticated operating modes, such as homogeneous charge compression ignition (HCCI) and Partially premixed Charge Compression Ignition (PCCI), often coupled with exhaust gas recirculation and/or aftertreatment are employed for regulating nitric oxide (NO x ) and soot emission levels. However, a totally homogeneous mixture is unachievable in practical engines. Inherent inhomogeneities in fuel concentration and temperature may significantly affect the ignition and combustion processes, hence various control strategies attract research interest. The present work demonstrates the potential of emission reduction in Diesel engines operating under high boost conditions through a combination of multi-injection strategies and high EGR schemes

Intratumoral CRH modulates immuno-escape of ovarian cancer cells through FasL regulation

Although corticotropin-releasing hormone (CRH) and Fas ligand (FasL) have been documented in ovarian carcinoma, a clear association with tumour progression and immuno-escape has not been established. FasL plays an important role in promoting tumour cells' ability to counterattack immune cells. Here, we examined immunohistochemically the expression of CRH, CRHR1, CRHR2 and FasL in 47 human ovarian cancer cases. The ovarian cancer cell lines OvCa3 and A2780 were further used to test the hypothesis that CRH might contribute to the immune privilege of ovarian tumours, by modulating FasL expression on the cancer cells. We found that CRH, CRHR1, CRHR2 and FasL were expressed in 68.1, 70.2, 63.8 and 63.8% of the cases respectively. Positivity for CRH or FasL expression was associated with higher tumour stage. Finally, CRH increased the expression of FasL in OvCa3 and A2780 cells through CRHR1 thereby potentiated their ability to induce apoptosis of activated peripheral blood lymphocytes. Corticotropin-releasing hormone produced by human ovarian cancer might favour survival and progression of the tumour by promoting its immune privilege. These findings support the hypothesis that CRHR1 antagonists could potentially be used against ovarian cancer

McCune-Albright syndrome

McCune-Albright syndrome (MAS) is classically defined by the clinical triad of fibrous dysplasia of bone (FD), café-au-lait skin spots, and precocious puberty (PP). It is a rare disease with estimated prevalence between 1/100,000 and 1/1,000,000. FD can involve a single or multiple skeletal sites and presents with a limp and/or pain, and, occasionally, a pathologic fracture. Scoliosis is common and may be progressive. In addition to PP (vaginal bleeding or spotting and development of breast tissue in girls, testicular and penile enlargement and precocious sexual behavior in boys), other hyperfunctioning endocrinopathies may be involved including hyperthyroidism, growth hormone excess, Cushing syndrome, and renal phosphate wasting. Café-au-lait spots usually appear in the neonatal period, but it is most often PP or FD that brings the child to medical attention. Renal involvement is seen in approximately 50% of the patients with MAS. The disease results from somatic mutations of the GNAS gene, specifically mutations in the cAMP regulating protein, Gs alpha. The extent of the disease is determined by the proliferation, migration and survival of the cell in which the mutation spontaneously occurs during embryonic development. Diagnosis of MAS is usually established on clinical grounds. Plain radiographs are often sufficient to make the diagnosis of FD and biopsy of FD lesions can confirm the diagnosis. The evaluation of patients with MAS should be guided by knowledge of the spectrum of tissues that may be involved, with specific testing for each. Genetic testing is possible, but is not routinely available. Genetic counseling, however, should be offered. Differential diagnoses include neurofibromatosis, osteofibrous dysplasia, non-ossifying fibromas, idiopathic central precocious puberty, and ovarian neoplasm. Treatment is dictated by the tissues affected, and the extent to which they are affected. Generally, some form of surgical intervention is recommended. Bisphosphonates are frequently used in the treatment of FD. Strengthening exercises are recommended to help maintaining the musculature around the FD bone and minimize the risk for fracture. Treatment of all endocrinopathies is required. Malignancies associated with MAS are distinctly rare occurrences. Malignant transformation of FD lesions occurs in probably less than 1% of the cases of MAS

Hyponatremia in visceral leishmaniasis

There are few reports linking hyponatremia and visceral leishmaniasis (kala-azar). This is a study of 55 consecutive kala-azar patients and 20 normal individuals as a control group. Hyponatremia and serum hypo-osmolality were detected in 100% of kala-azar patients. High first morning urine osmolality (750.0 ± 52.0 vs. 894.5 ± 30.0mOsm/kg H2O, p Existem poucos relatos relacionando hiponatremia com a leshmaniose visceral (calazar). Este é um estudo de 55 pacientes portadores de calazar e um grupo controle de 20 indivíduos normais. Hiponatremia e hipo-osmolalidade sérica foram detectados em 100% dos pacientes portadores de calazar. A presença de alta osmolalidade da primeira urina da manhã (750,0 ± 52,0 vs. 894,5 ± 30 mOsm/Kg H2O, p < 0,05) e da urina de 24h (426,0 ± 167,0 vs. 514,6 ± 132,0 mOsm/Kg H2O, p < 0,05), demonstraram a presença de persistente secreção de hormônio antidiurético. A concentração de sódio urinário foi elevada (82,3 ± 44,2 vs. 110,3 ± 34,7 mEq/L, p < 0,05). Hipouricemia ocorreu em 61,8% dos pacientes e aumento da fração de excreção urinária de ácido úrico foi detectada em 74,5% dos casos. Aumento da velocidade de filtração glomerular estava presente em 25,4% dos pacientes. Não havia evidência clínica de depleção de volume extracelular. Valores normais de ADH plasmático foram observados nos pacientes com calazar. Não foi detectada disfunção renal ou endócrina. É provável, que a maioria dos pacientes com calazar apresente uma síndrome de secreção inapropriada de hormônio antidiurético

Potential plasma markers of type 1 and type 2 leprosy reactions: a preliminary report

<p>Abstract</p> <p>Background</p> <p>The clinical management of leprosy Type 1 (T1R) and Type 2 (T2R) reactions pose challenges mainly because they can cause severe nerve injury and disability. No laboratory test or marker is available for the diagnosis or prognosis of leprosy reactions. This study simultaneously screened plasma factors to identify circulating biomarkers associated with leprosy T1R and T2R among patients recruited in Goiania, Central Brazil.</p> <p>Methods</p> <p>A nested case-control study evaluated T1R (n = 10) and TR2 (n = 10) compared to leprosy patients without reactions (n = 29), matched by sex and age-group (+/- 5 years) and histopathological classification. Multiplex bead based technique provided profiles of 27 plasma factors including 16 pro inflammatory cytokines: tumor necrosis factor-α (TNF-α), Interferon-γ (IFN-γ), interleukin (IL)- IL12p70, IL2, IL17, IL1 β, IL6, IL15, IL5, IL8, macrophage inflammatory protein (MIP)-1 alpha (MIP1α), 1 beta (MIP1β), regulated upon activation normal T-cell expressed and secreted (RANTES), monocyte chemoattractrant protein 1 (MCP1), CC-chemokine 11 (CCL11/Eotaxin), CXC-chemokine 10 (CXCL10/IP10); 4 anti inflammatory interleukins: IL4, IL10, IL13, IL1Rα and 7 growth factors: IL7, IL9, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), platelet-derived growth factor BB (PDGF BB), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF).</p> <p>Results</p> <p>Elevations of plasma CXCL10 (P = 0.004) and IL6 (p = 0.013) were observed in T1R patients compared to controls without reaction. IL6 (p = 0.05), IL7 (p = 0.039), and PDGF-BB (p = 0.041) were elevated in T2R. RANTES and GMCSF were excluded due to values above and below detection limit respectively in all samples.</p> <p>Conclusion</p> <p>Potential biomarkers of T1R identified were CXCL10 and IL6 whereas IL7, PDGF-BB and IL6, may be laboratory markers of TR2. Additional studies on these biomarkers may help understand the immunopathologic mechanisms of leprosy reactions and indicate their usefulness for the diagnosis and for the clinical management of these events.</p