Physical study of the non-equilibrium development of a turbulent thermal boundary layer

The direct numerical simulation of a non-equilibrium turbulent heat transfer case is performed in a channel flow, where non-equilibrium is induced by a step change in surface temperature. The domain is thus made of two parts in the streamwise direction. Upstream, the flow is turbulent, homogeneous in temperature and the channel walls are adiabatic. The inflow conditions are extracted from a recycling plane located further downstream, so that a fully developed turbulent adiabatic flow reaches the second part. In the domain located downstream, isothermal boundary conditions are prescribed at the walls. The boundary layer, initially at equilibrium, is perturbed by the abrupt change of boundary conditions, and a non-equilibrium transient phase is observed until, further downstream, the flow reaches a new equilibrium state, presenting a fully developed thermal boundary layer. The work aims at identifying the non-equilibrium effects that are expected to be encountered in comparable flows, while providing the means to understand them. In particular, the study allows for the identification of an inner region of the developing boundary layer where several quantities are at equilibrium. Other quantities, instead, exhibit a behaviour of their own, especially in proximity to the leading edge. The analysis is supported by mean and root-mean-square profiles of temperature and velocity, as well as by budgets of first- and second-order moment balance equations for the enthalpy and momentum turbulent fields.

Development of an integrated cooling system for motorcycle helmet by physical study of temperature variations and heat transfer

In Colombia, the most widely used means of transport today are motorcycles, which have become increasingly numerous, bearing in mind that they are subject to laws and regulations imposed by the country’s mobility, transit and transport agencies, the use of helmets is mandatory for drivers and passengers, safety measures are monitored, the hull must be certified and meet the required technical standards; whereas its role is to protect people in the event of accidents, regulations require that the helmet be completely closed to protect the entire head and chin; the design of the helmet allows air entry and there is no concentration of temperature inside, all this is done by implementing air inlet and outlet ducts, which circulate air when the motorcycle is in motion, unfortunately this does not happen due to the accumulation of temperature in the back of the helmet that makes the user feel tired and uncomfortable. This research proposes the development of a prototype portable cooling system for motorcycle helmets by the physical principle of heat transfer, by using Peltier cells, to have low production cost, optimal operation, and low energy consumption thanks to natural air flow.

Experimental and theoretical observations of alkylated EOSIN based “turn-on” superoxide sensor as well as its anti-microbial study

The alkylating as well as alkoxylating behavior of dialkyl sulfites are well presented in the literature. In the present work dialkyl sulphites behavior has been investigated towards EOSIN Y (tetrabrominated fluorescein). The products of the reactions (dialkylated eosin Y) reveal that alkylation takes place at the both active sites (at hydroxyl and carboxyl functionalities) in a single step through sulphur-centred Arbuzov type rearrangement. Density functional theory (DFT) has been used as a tool to analyze the role of the halogen groups present at the periphery of the xanthene moiety in alkylation at hydroxyl and carboxy positions of EOSIN Y. Furthermore, in photo-physical study, it was observed that compound C acts as a superoxide sensor specifically with the detection limit 63μM. Its anti-microbial activity was checked against the E. coli and S-aureus using the agar well diffusion assay and, it was observed that it could be used as better antimicrobial agent.

Numerical and physical study of transitions to unsteady modes of melt flow with the Prandtl number 16 in the Czochralski method

The evolution of the flow structure and heat transfer with an increase in the characteristic temperature drop in the ranges of Grashof and Marangoni numbers 3558 ≤ Gr ≤ 7116 and 2970 ≤ Ma ≤ 5939 are investigated numerically. The boundary of the transition to unsteady flow and heat transfer regimes has been determined.

Lessons Learned Recruiting and Retaining Pregnant and Postpartum Individuals in Digital Trials (Preprint)

UNSTRUCTURED In an increasingly connected world and in the midst of a global pandemic, digital trials offer numerous advantages over traditional trials that rely on physical study sites. Digital trials have the potential to improve access to research and clinical treatments for the most vulnerable and minoritized, including pregnant and postpartum individuals. However, digital trials are underutilized in maternal and child health research, and there is limited evidence to inform the design and conduct of digital trials. Our research collaborative, consisting of five research teams in the U.S. and Australia, aimed to address this gap. We collaborated to share lessons learned from our experiences recruiting and retaining pregnant and postpartum individuals in digital trials of social and behavioral interventions. We first discuss the promise of digital trials in improving participation in research during the perinatal period as well as the unique challenges they pose. Second, we present lessons learned from 12 completed and ongoing digital trials that have used platforms such as Ovia, Facebook, and Instagram to recruitment. Our trials have evaluated interventions for breastfeeding, prenatal and postpartum depression, insomnia, decision-making, and chronic pain. We focus on challenges and lessons learned in three key areas 1) rapid recruitment of large samples with a diversity of minoritized identities; 2) retention of study participants in longitudinal studies; and 3) preventing fraudulent enrollment. We offer concrete strategies that we have pilot tested to address these challenges. Strategies presented in this commentary can be incorporated into as well as formally evaluated in future studies.

Design of an edge TV Thomson scattering diagnostic system on EAST

The study of the edge plasma has significant effect for the performance improvement of magnetic confinement. However, the Thomson scattering system, which has been used to provide electron temperature and electron density on EAST, do not meet the requirements for the edge plasma measurements in measurement region, spatial and spectral resolution. Herein, a TV Thomson scattering diagnostic system has been constructed for the measurements of edge electron temperature and electron density profiles on EAST. A new laser system, optical collection system and data acquisition system are designed to enable the TV Thomson system operate at the measurement region of 0.65–1.1 ρ (“ρ” is the unitary radius in flux coordinate) with spectral resolution of 5 nm and spatial resolution as low as 2 mm. And the theoretical analysis proves that the system has the measurability at electron temperature of 20–1000 eV and density beyond 0.2 × 1019 m-3, which fulfills research of the pedestal microstructure on EAST. The establishment of the edge TV Thomson system can create the conditions for the edge physical study on EAST.

Development of an electro-pneumatic system for the practical training of pneumatic processes in the university environment

This article describes the implementation of an electro-pneumatic test bench, which allows the availability of a physical environment to promote learning. The aim of the paper is to create a tool that enables practical training and research of pneumatic processes for university students in the field of engineering. The control and automation system of the test bench is made up of wired logic panels, timers, and programmable logic controllers, which are integrated into a control board configured at 24 V (direct current) to guarantee safety. Additionally, ergonomic principles were considered for the construction of the electro-pneumatic bench, thus favoring the accessibility and safety of the users. Based on national and international regulations, working pressure of 9 bar and an approximate pressure drop of 0.07 bar were defined. The construction of the test bench is considered an educational strategy to facilitate and accelerate the learning process of the students. Additionally, the development of the electro-pneumatic bench allowed the dynamic characterization of double-acting actuators by integrating experimental data and numerical models. This allowed the detailed analysis of the displacement, velocity, and acceleration variables in this type of actuator, which contributes to the physical study of pneumatic systems.

Ventajas nutritivas y terapéuticas del agua de mar en el Ecuador durante pandemia

Las poblaciones ante la virulencia del COVID19 mostraron la pérdida de su bienestar y las opciones alimentarse adecuadamente para resistir al confinamiento, o para salvar vida pusieron en ejercicio a los conocimientos científicos de varios grupos de profesionales, que se encontraron ante un virus poco estudiado con una gran letalidad. Para ello se realizó una investigación analítica eligiendo la literatura científica de aplicación del francés Quinton, quien había descubierto las propiedades del agua de mar, y de algunas plantas medicinales. Se realiza una investigación de campo, orientada a establecer los beneficios anticoagulantes del agua de mar en un consumo adecuado de 30 ml en las personas que alejadas de los fármacos acudieron a la misma como un recurso que mineralizó el cuerpo y sin saberlo al inició de la investigación evitó la coagulación de la sangre en personas que venían bebiendo agua de mar debidamente tratada. De esa manera, en forma inconsciente con los minerales que tenían en su cuerpo por la ingesta de agua de mar procesada, permitió que anticoagulantes naturales como el magnesio actuara como una barrera dentro de la cascada de coagulación, evitando que colapsen los pulmones por los componentes de la misma. La investigación tiene como objetivo establecer el aporte científico del conocimiento de la dosificación del agua de mar en el mejoramiento el bienestar y desarrollo de nuestros pueblos entrevistando a aquellos que la utilizaron para recoger información directa sobre sus beneficios orgánicos según su aplicación. Es un estudio cuantitativo y comparativo de las recomendaciones de la OMS se establecen las pautas mediante el proceso del método científico de observación, análisis, hipótesis y conclusiones. El análisis elige como tamaño de la muestra a 100 personas que se recuperaron luego de la administración del mar respaldado por un análisis de las historias clínicas y estudios de laboratorio luego de su aplicación. Entre los resultados está que el agua de mar ozonificada, en el 90% de la población que mostró ahogamiento a partir de la segunda semana de virulencia al administrarse agua de mar, mostró recuperación a las 72 horas y un restablecimiento progresivo. En el estudio físico de la sangre durante y después de la administración del agua de mar, se observaron cambios en la coloración de la sangre y en la capacidad coaguladora. Populations in the face of the virulence of COVID19 showed the loss of their well-being and the options to eat properly to resist confinement, or to save life, put into practice the scientific knowledge of several groups of professionals, who were faced with a little-studied virus with a great lethality. For this, an analytical investigation was carried out choosing the scientific literature of the French Quinton, who had discovered the properties of seawater, and of some medicinal plants. A field investigation is carried out, aimed at establishing the anticoagulant benefits of seawater in an adequate consumption of 30 ml in people who, away from drugs, resorted to it as a resource that mineralized the body and without knowing it at the beginning of the research prevented blood clotting in people who had been drinking properly treated seawater. In this way, unconsciously with the minerals that they had in their body from the intake of processed seawater, it allowed natural anticoagulants such as magnesium to act as a barrier within the coagulation cascade, preventing the lungs from collapsing due to the components Of the same. The objective of the research is to establish the scientific contribution of the knowledge of seawater dosage in improving the well-being and development of our peoples by interviewing those who used it to collect direct information on its organic benefits according to its application. It is a quantitative and comparative study of the WHO recommendations, the guidelines are established through the process of the scientific method of observation, analysis, hypotheses and conclusions. The analysis chooses as the sample size 100 people who recovered after the administration of the sea supported by an analysis of medical records and laboratory studies after its application. Among the results is that ozonated seawater, in 90% of the population that showed drowning from the second week of virulence when seawater was administered, showed recovery at 72 hours and a progressive recovery. In the physical study of the blood during and after the administration of seawater, changes in the color of the blood and in the coagulant capacity were observed.