Orientational order parameters of a de Vries–type ferroelectric liquid crystal obtained by polarized Raman spectroscopy and x-ray diffraction

The orientational order parameters 〈P2〉 and 〈P4〉 of the ferroelectric, de Vries–type liquid crystal 9HL have been determined in the SmA* and SmC* phases by means of polarized Raman spectroscopy, and in the SmA* phase using x-ray diffraction. Quantum density functional theory predicts Raman spectra for 9HL that are in good agreement with the observations and indicates that the strong Raman band probed in the experiment corresponds to the uniaxial, coupled vibration of the three phenyl rings along the molecular long axis. The magnitudes of the orientational order parameters obtained in the Raman and x-ray experiments differ dramatically from each other, a discrepancy that is resolved by considering that the two techniques probe the orientational distributions of different molecular axes. We have developed a systematic procedure in which we calculate the angle between these axes and rescale the orientational order parameters obtained from x-ray scattering with results that are then in good agreement with the Raman data. At least in the case of 9HL, the results obtained by both techniques support a “sugar loaf” orientational distribution in the SmA* phase with no qualitative difference to conventional smectics A. The role of individual molecular fragments in promoting de Vries–type behavior is considered

Advanced Manifolds for Improved Solid Oxide Electrolyzer Performance

An investigation was conducted to see if additive manufacturing could be used to fabricate more efficient manifold designs for improved flow, reduced stresses, and decreased number of joints to be sealed for a solid oxide electrolyzer used to convert carbon dioxide to oxygen. Computational flow and mechanical modeling were conducted on a NASA Glenn Research Center patented cell and stack design with the potential to achieve a 3-4 times mass reduction. Various manifold designs were modeled, and two were downselected to be fabricated and tested. Some benefit was seen in a baffled manifold design, which directed incoming flow more effectively into the flow channels, compared to the original design, where the flow spent more time within the manifold itself. Flow measurements indicated some non-uniformity of flow across the channels at higher flow rates, which were not predicted by the model. Some possible explanations for the differences are discussed

Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows

The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions

Designing a Free Academic Early Alert System

This manuscript describes the development and implementation of a cloud-based, academic early alert system using Google Sheets. It was written for a non-computer savvy person to be able to develop the early alert system. By creating a Master Sheet and using the syntax from the share function of Google Sheets, a unique sheet can be created for each advisor that limits information sharing of their specific advisees. By adding a Google Form to the sheet, advisor interventions can be captured that reflect interventions made as a result of the early alert sheet. Approximately 52% of students were identified on the early alert sheet by having at least one non-passing score on an exam. There were 35-50% of faculty advisors who documented their interventions in the sheet. The template and coding used to develop this academic early alert sheet may be applied to other central documentation needs, such as professionalism early alert. Conflict of Interest Dr. Welch reports owning stock in Alphabet, Inc, however, was not involved in the selection of Google as the preferred platform at this institution.   Type: Not

Designing a Free Academic Early Alert System

This manuscript describes the development and implementation of a cloud-based, academic early alert system using Google Sheets. It was written for a non-computer savvy person to be able to develop the early alert system. By creating a Master Sheet and using the syntax from the share function of Google Sheets, a unique sheet can be created for each advisor that limits information sharing of their specific advisees. By adding a Google Form to the sheet, advisor interventions can be captured that reflect interventions made as a result of the early alert sheet. Approximately 52% of students were identified on the early alert sheet by having at least one non-passing score on an exam. There were 35-50% of faculty advisors who documented their interventions in the sheet. The template and coding used to develop this academic early alert sheet may be applied to other central documentation needs, such as professionalism early alert. Conflict of Interest Dr. Welch reports owning stock in Alphabet, Inc, however, was not involved in the selection of Google as the preferred platform at this institution.   Type: Not

Diet or exercise, or both, for weight reduction in women after childbirth

Background: Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated. Objectives: The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes. Search methods: We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (31 January 2012) and LILACS (31 January 2012). We scanned secondary references and contacted experts in the field. We updated the search of the Cochrane Pregnancy and Childbirth Group’s Trials Register on 30 April 2013 and added the results to the awaiting classification section of the review. Selection criteria: All published and unpublished randomised controlled trials (RCTs) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period. Data collection and analysis Both review authors independently assessed trial quality and extracted data. Results are presented using risk ratio (RR) for categorical data and mean difference (MD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity. Main results: Fourteen trials were included, but only 12 trials involving 910 women contributed data to outcome analysis. Women who exercised did not lose significantly more weight than women in the usual care group (two trials; n = 53; MD -0.10 kg; 95% confidence interval (CI) -1.90 to 1.71). Women who took part in a diet (one trial; n = 45; MD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (seven trials; n = 573; MD -1.93 kg; 95% CI -2.96 to -0.89; random-effects, T² = 1.09, I² = 71%), lost significantly more weight than women in the usual care group. There was no difference in the magnitude of weight loss between diet alone and diet plus exercise group (one trial; n = 43; MD 0.30 kg; 95% CI -0.06 to 0.66). The interventions seemed not to affect breastfeeding performance adversely. Authors’ conclusions: Evidence from this review suggests that both diet and exercise together and diet alone help women to lose weight after childbirth. Nevertheless, it may be preferable to lose weight through a combination of diet and exercise as this improves maternal cardiorespiratory fitness and preserves fat-free mass, while diet alone reduces fat-free mass. This needs confirmation in large trials of high methodological quality. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby

Dieta o ejercicio, o ambos, para la reducción de peso en mujeres después del parto

Antecedentes: La retención de peso después del embarazo puede contribuir a la obesidad. Se conoce que la dieta y el ejercicio son los componentes recomendados de cualquier programa de pérdida de peso para la población en general. Sin embargo, no se han evaluado adecuadamente las estrategias para lograr un peso corporal posparto saludable entre las mujeres. Objetivos: Los objetivos de esta revisión fueron evaluar el efecto de la dieta, el ejercicio o ambos para la reducción de peso en las mujeres después del parto y evaluar la repercusión de estas intervenciones sobre la composición corporal materna, el estado físico cardiorrespiratorio, el rendimiento de la lactancia y otros resultados maternoinfantiles. Estrategia de búsqueda: Se realizaron búsquedas en el registro de ensayos del Grupo Cochrane de Embarazo y Parto (Cochrane Pregnancy and Childbirth Group) (septiembre 2006) y LILACS. Se revisaron las referencias secundarias y se estableció contacto con expertos en el campo. Criterios de selección: Todos los ensayos controlados aleatorios (ECA) publicados y no publicados y los ensayos cuasialeatorios de dieta o ejercicio o ambos, entre las mujeres durante el período posparto. Recopilación y análisis de datos: Tres revisores evaluaron de forma independiente la calidad de los ensayos y extrajeron los datos. Para presentar los resultados se utilizó el riesgo relativo para los datos categóricos y la diferencia de medias ponderada (DMP) para los datos continuos. Los datos se analizaron con un modelo de efectos fijos. Cuando hubo heterogeneidad se utilizó un modelo de efectos aleatorios. Resultados principals: Se incluyeron seis ensayos con 245 mujeres. Las mujeres que hicieron ejercicio no perdieron significativamente más peso que las mujeres del grupo de atención habitual (un ensayo; n = 33; DMP 0,00 kg; intervalo de confianza [IC] del 95%: -8,63 a 8,63). Las mujeres que siguieron una dieta (un ensayo; n = 45; DMP -1,70 kg; IC del 95%: -2,08 a -1,32) o una dieta más un programa de ejercicio (cuatro ensayos; n = 169; DMP -2,89 kg; IC del 95%: -4,83 a -0,95), perdieron significativamente más peso que las mujeres que recibieron atención habitual. No hubo diferencias en la magnitud de la pérdida de peso entre el grupo de dieta y el de dieta más ejercicio (un ensayo; n = 43; DMP 0,30 kg; IC del 95%: -0,60 a 0,66). Las intervenciones no parecieron afectar negativamente el rendimiento de la lactancia materna. Conclusiones de los autores: Las pruebas preliminares de esta revisión indican que seguir una dieta junto con ejercicio parece ser más efectivo que la dieta sola para ayudar a las mujeres a perder peso después del parto, porque la primera opción mejora el nivel del estado físico cardiorrespiratorio materno y preserva la masa magra, mientras que la dieta sola reduce la masa magra. En el caso de las mujeres que lactan, se necesitan más pruebas para confirmar si la dieta o el ejercicio, o ambos, no son perjudiciales para la madre o el neonato. Debido a los insuficientes datos disponibles, se necesitan investigaciones adicionales con un tamaño de la muestra más grande para confirmar los resultados

Effect of physical activity intervention based on a pedometer on physical activity level and anthropometric measures after childbirth: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Pregnancy and childbirth are associated with weight gain in women, and retention of weight gained during pregnancy can lead to obesity in later life. Diet and physical activity are factors that can influence the loss of retained pregnancy weight after birth. Exercise guidelines exist for pregnancy, but recommendations for exercise after childbirth are virtually nonexistent. The aim of this study was to evaluate the effect of physical activity intervention based on pedometer on physical activity level and anthropometric measures of women after childbirth.</p> <p>Methods</p> <p>We conducted a randomized controlled trial in which 66 women who had given birth 6 weeks to 6 months prior were randomly assigned to receive either a 12 week tailored program encouraging increased walking using a pedometer (intervention group, n = 32) or routine postpartum care (control group, n = 34). During the 12-week study period, each woman in the intervention group wore a pedometer and recorded her daily step count. The women were advised to increase their steps by 500 per week until they achieved the first target of 5000 steps per day and then continued to increase it to minimum of 10,000 steps per day by the end of 12^thweek. Assessed outcomes included anthropometric measures, physical activity level, and energy expenditure per week. Data were analyzed using the paired t-test, independent t-test, Mann-Whitney, chi-square, Wilcoxon, covariance analysis, and the general linear model repeated measures procedure as appropriate.</p> <p>Results</p> <p>After 12 weeks, women in the intervention group had significantly increased their physical activity and energy expenditure per week (4394 vs. 1651 calorie, <it>p </it>< 0.001). Significant differences between-group in weight (<it>P </it>= 0.001), Body Mass Index (<it>P </it>= 0.001), waist circumference (<it>P </it>= 0.001), hip circumference (<it>P </it>= 0.032) and waist-hip ratio (<it>P </it>= 0.02) were presented after the intervention. The intervention group significantly increased their mean daily step count over the study period (from 3249 before, to 9960 after the intervention, <it>p </it>< 0.001).</p> <p>Conclusion</p> <p>A physical activity intervention based on pedometer is an effective means to increase physical activity; reducing retention of weight gained during pregnancy and can improve anthropometric measures in postpartum women.</p> <p>Trial registration</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/IRCT201105026362N1">IRCT201105026362N1</a></p

Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation

[EN] In this paper, a research aimed at quantifying mass and momentum transfer in the near-nozzle field of diesel sprays injected into stagnant ambient air is reported. The study combines X-ray measurements for two different nozzles and axial positions, which provide mass distributions in the spray, with a theoretical model based on momentum flux conservation, which was previously validated. This investigation has allowed the validation of Gaussian profiles for local fuel concentration and velocity near the nozzle exit, as well as the determination of Schmidt number at realistic diesel spray conditions. This information could be very useful for those who are interested in spray modeling, especially at high-pressure injection conditions. © 2010 Springer-Verlag.This work was partly sponsored by "Vicerrectorado de Investigacion, Desarrollo e Innovacion'' of the "Universidad Politecnica de Valencia'' in the frame of the project "Estudio del flujo en el interior de toberas de inyeccion Diesel'', reference no. 3150 and by "Generalitat Valenciana'' in the frame of the project with the same title and reference GV/2009/031. This support is gratefully acknowledged by the authors.Desantes, J.; Salvador Rubio, FJ.; López, JJ.; De La Morena, J. (2011). Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation. Experiments in Fluids. 50(2):233-246. https://doi.org/10.1007/s00348-010-0919-8S233246502Abramovich GN (1963) The theory of turbulent jets. 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