An ingenious technique for functional palatal reservoir construction in complete dentures

The retention, stability and comfort of wearing denture is greatly influenced by the flow, quantity and consistency of saliva. Insufficient salivary output results especially in old-aged edentulous patients may result in denture sores because of lack of lubrication by saliva, thus, reducing patient’s ability to retain the prosthesis. Various approaches have been concernes with the use of reservoir with holes have been described in the literature. However the flow of salivary substitute is very difficult to control. Moreover the frequent cleaning of the denture required to maintain the patency of the reservoir holes poses various challenges to the patient. This article explains a novel technique for the incorporation of a reservoir with controlled salivary flow in complete denture to enhance the retention of the prosthesis and thus, improving the comfort of wearing denture and the speech of patient.

Brazilian position in the international fresh fruit trade network

The fruit growing activity is of great importance for Brazilian agribusiness as the country is the third largest fruit producer in the world. Despite this notability, the fruit market presents obstacles especially related to international trade. Thus, the present study sought to determine the positioning and evolution of Brazil in the international fresh fruit market. Data used in the research were obtained from the Food and Agriculture Organization of the United Nations (FAO) (1986 to 2017) and the World Bank (2018), using metrics of export flow, quantity and income of countries related to the main fruits exported by Brazil in the first quarter of 2020. Data were manipulated, transformed into figures and graphs for better visualization of information. The Brazilian position in the in the ranking of fresh fruit exports was not very dynamic during the evaluation period, being dependent on the demand from high-income European countries.

Spatial Flow-Field Approximation Using Few Thermodynamic Measurements—Part I: Formulation and Area Averaging

Our investigation raises an important question that is of relevance to the wider turbomachinery community: how do we estimate the spatial average of a flow quantity given finite (and sparse) measurements? This paper seeks to advance efforts to answer this question rigorously. In this paper, we develop a regularized multivariate linear regression framework for studying engine temperature measurements. As part of this investigation, we study the temperature measurements obtained from the same axial plane across five different engines yielding a total of 82 datasets. The five different engines have similar architectures and therefore similar temperature spatial harmonics are expected. Our problem is to estimate the spatial field in engine temperature given a few measurements obtained from thermocouples positioned on a set of rakes. Our motivation for doing so is to understand key engine temperature modes that cannot be captured in a rig or in computational simulations, as the cause of these modes may not be replicated in these simpler environments. To this end, we develop a multivariate linear least-squares model with Tikhonov regularization to estimate the 2D temperature spatial field. Our model uses a Fourier expansion in the circumferential direction and a quadratic polynomial expansion in the radial direction. One important component of our modeling framework is the selection of model parameters, i.e., the harmonics in the circumferential direction. A training-testing paradigm is proposed and applied to quantify the harmonics.

HEMODYNAMIC INVESTIGATION OF SUBCLAVIAN-CORONARY STEAL SYNDROME IN DIALYSIS PATIENTS WITH CORONARY ARTERY OCCLUSION AND DIFFERENT STENOSIS PERCENTAGES IN SUBCLAVIAN ARTERY

Purpose: Diseases of the coronary arteries represent critical cardiovascular bleakness and mortality around the world. The main focus of this study is to simulate hemodialysis patients undergoing Coronary Artery Bypass Graft (CABG) surgery by the left internal mammary artery. The survey is to investigate whether subclavian-coronary steal syndrome will occur in patients with stenosis in their left subclavian. Methods: A three-dimensional model of Brachial—Radial—Ulnar tree arterial system and dialysis graft are constructed and then simulated by the implementation of fluid–structure interaction (FSI) and non-FSI models. After consent was obtained, data attributed to dialysis patients who had undergone coronary bypass surgery at the Tehran Heart Center (THD) was collected. Results: Stenosis in the subclavian artery causes the left internal mammary artery (LIMA) graft to lack flow that, in CABG cases, is supplying the heart muscle. With the increase of stenosis from zero to 54%, the flow results show a negative flow indicating reversed flow in the artery. Meanwhile, the comparison between flow quantity of a normal Left Anterior Descending (LAD) and LIMA in case of 38% stenosis in subclavian shows that the amount of flow reaching the heart is less than standard. The threshold stenosis in the subclavian artery for which subclavian-coronary steal phenomena occurs is simulated to be around 54%. Furthermore, investigation of the effect of flow quantity in cases of hemodialysis versus nonhemodialysis shows that the flow is lessened in case of hemodialysis. Conclusions: In hemodialysis patients with more than 38% stenosis in left subclavian, it is well advised that LIMA bypass graft is not the preferred graft choice, and at 54% of subclavian stenosis, the steal phenomenon occurs.

Hydrocarbon Accounting Verification for Reasonable Assurance on EJGP Open Access Pipe System

<p>The East Java Gas Pipeline (EJGP) pipeline network system is an open access for transporting almost ± 310 MMSCFD of Natural Gas from fields in East Java offshore to the onshore Power Plant consumers. The deviation between the calculated and mass balance of gas stock is called the Discrepancy in which BPHMIGAS set up a maximum value of ± 0.85%. The objective of the study is to develop a verification methodology to support hydrocarbon accounting in the EJGP Pipeline Network System. The methodology will be assisted by Flow Quantity Assurance software. After obtaining sufficient data, a new baseline can be taken empirically which can be used as a reference for the maximum allowable discrepancy in the EJGP Pipeline Network System. The data used in this simulation are taken from September - October 2013 such as pipes dimension of the entire network piping system, flowrate, pressure, temperature, and the composition of natural gas. The results of verification are compared with the calculations carried out by Pertamina Gas as operators. The calculation of Discrepancy from the Operators with different tools is around 0.12%, meaning that operator calculations are acceptable. The maximum <br />allowable discrepancy ± 0.85%, can be reviewed to be reduced according to the history of the average system discrepancy in 2017-2018 (around 0.54%). The New Shipper from Sirasun Batur Field is still more economics by using the existing pipeline network even though it bears Discrepancy / Losses up to 1% compared to building new pipes to consumers. It is found that the discrepancy is getting smaller (reducing the error) if there is a gas balance, meaning that the end consumers will take the gas according to the agreed nomination.</p>

Experimental Research of High-Temperature and High-Pressure Water Jet Characteristics in ICRC Engine Relevant Conditions

The internal combustion Rankine cycle (ICRC) concept provides a potential solution for future high thermal efficiency and low emission powertrains, and direct water injection (DWI) proved to be the key parameter for ICRC optimization. This paper was dedicated to investigating the fundamental mechanisms of water spray characteristics under different water injection control parameters. In order to do so, an experimental test system was carefully designed and built based on the Bosch and Schlieren methods: the Bosch method is utilized to measure the effect of injection and ambient pressure on water injection characteristics, and the Schlieren method is utilized to investigate the impact of water injection and ambient temperature on water spray and evaporation processes. The experimental results indicate that both control parameters show important effects on water injection and spray characteristics. The water injection and ambient pressure show significant impacts on steady-state flow quantity and cyclic water injection quantity, and the water injection and ambient pressure affect the evaporation ability of water vapor within the spray which leads to a different variation trend during the initial, developing, and developed water spray stages. The results of this work can be used as fundamental supplements for ICRC, steam assistant technology (SAT), and DWI-related ICEs experimental and numerical researches, and provide extra information to understand the DWI process within engine-relevant conditions.

Estudio aerodinámico del avión de entrenamiento de vuelo “KUNTUR”

Estudio aerodinámico del avión de entrenamiento de vuelo “KUNTUR” Aerodynamic study of the plane of training flight “KUNTUR” Jhonatan Paín, Gabriel Cárdenas, José Luna y Luis Romero Escuela de Oficiales de la Fuerza Aérea del Perú. Av. Jorge Chávez S/N, Surco Facultad de Ingeniería Ambiental, Universidad Alas Peruanas. Av. P. Ruíz Gallo 251, Pueblo Libre. Facultad de Ingeniería, Universidad Privada Norbert Wiener. Jr. Larrabure y Unanue 110, Lima. DOI: https://doi.org/10.33017/RevECIPeru2011.0004/ RESUMEN El presente trabajo se realizó en las instalaciones de la Escuela de Oficiales y del Servicio de Mantenimiento de la Fuerza Aérea del Perú, ubicadas en la Base Aérea “Las Palmas” - Surco, con el objetivo de determinar la respuesta aerodinámica del avión de entrenamiento BD-4BP, conocido como “Kuntur”, a la velocidad de crucero de 174 MPH [1,2]. El Kuntur, es un avión diseñado y construido en el Perú y cuenta con tecnología hibrida, es por ello la importancia de desarrollar este trabajo. Para el desarrollo de la presente investigación se aplicó la metodología deductiva, con lo cual se pudieron determinar los vectores de velocidad y presión en torno al avión, para ello se empleó el software computacional en dinámica de fluidos - CFD “Fluent”, el cual realiza un cálculo basado en el método de volúmenes finitos [3,4]. Los materiales que se utilizaron fueron, una computadora personal Pentium IV con alta velocidad de procesamiento de datos, el software CDF Fluent v6.2, modelos a escala y un túnel de viento subsónico. La simulación es realizada en 2D y primeramente se malla el avión, para lo cual se definen las estructuras y posteriormente se colocan los parámetros aerodinámicos (velocidad de avión, presión atmosférica, viscosidad del fluido, número de Reynolds, tipo de flujo, cantidad de interacciones), obteniéndose con ello valores que luego de realizar el tratamiento estadístico son presentados en tablas y gráficas. Los resultados presentados en este trabajo corresponden a la simulación y muestran los perfiles de velocidad y de presión en los diferentes puntos de la aeronave; así también, las evaluaciones son realizadas a diferentes ángulos de ataque de la aeronave observándose la turbulencia en torno al perfil, concluyéndose que el ángulo de ataque no sobrepase los 18º porque entra en perdida. Se recomienda continuar con la investigación en 3 dimensiones, para que complemente el diseño y performance del avión de entrenamiento Kuntur. Descriptores: Aerodinámica, Kuntur, velocidad de crucero, simulación, CFD Fluent, volúmenes finitos. ABSTRACT The present work realized in the facilities of the School of Officials and of the Service of Maintenance of the Air Force of Peru, located in the Air Base "Las Palmas" - Rut, with the aim to determine the aerodynamic response of the plane of training BD-4BP, known as "Kuntur", to the cruising speed of 174 MPH [1,2]. The Kuntur, it is a plane designed and constructed in Peru and possesses hybrid technology, there is for it the importance of developing this work. For the development of the present investigation the deductive methodology was applied, with which they could determine the vectors of speed and pressure concerning the plane, for it there used the computational software in dynamics of fluids - CFD "Fluent", which realizes a calculation based on the method of finite volumes [3,4]. Materials that were in use were, a personal computer Pentium IV with high speed of processing of information, the software CDF Fluent v6.2, models to scale and a tunnel of subsonic wind. The simulation is realized in 2D and first mesh the plane, for which the structures are defined and later there are placed the aerodynamic parameters (speed of plane, atmospheric pressure, viscosity of the fluid, number of Reynolds, type of flow, quantity of interactions), there being obtained by it values that after realizing the statistical treatment are presented in tables and graphs. The results presented in this work correspond to the simulation and show the profiles of speed and of pressure in the different points of the aircraft; this way also, the evaluations are realized to different angles of assault of the aircraft the turbulence being observed concerning the profile, concluding that the angle of assault does not exceed the 18 º that it enters loss. It is recommended to continue by the investigation in 3 dimensions, in order that it complements the design and performance of the plane of training Kuntur. Keywords: Aerodynamics, Kuntur, cruising speed, simulation, CFD Fluent, finite volumes.

ON THE MONITORING OF THE GAS-SOLID FLOWS IN INDUSTRIAL FLUIDIZED BEDS BY USING ELECTRICAL CHARGE SENSORS

The fluidized bed technology has been used in many industrial processes. It promotes good rates of heat, mass transfer and chemical reaction by generating high level of gas-solid mixture. However, the assurance of quality and efficiency of these processes requires the monitoring of the gas-solid flow. For this propose, there are some sensing techniques that allows generating dynamic signals from cold or hot fluidized beds. They are based on pressure fluctuations, acoustic and mechanical vibrations, electrical capacitance and on electrical charges. Electrical charge sensors were proposed originally for measuring the flow velocity in pneumatic conveying. They are composed of one or more metallic electrodes that detect electrical charges in the gas-solid flow, which are generated by particle-particle and particle-wall interaction due to triboelectric effect. In this work, such sensors are explored as a robust and inexpensive solution for the monitoring of industrial fluidized beds. However, since research investments are requested specially on the design of the sensor, concerning the flow quantity of interest and the electrification processes acting on the sensor, in this work different configurations were classified from information in literature, and other were proposed in this work concerning their use with industrial fluidized beds. Although the relation between magnitude of the detected charges and some physical quantities of the flow, such as concentration, is still not clear, other important information can be obtained by analyzing dynamic signals, as velocity or bubbles frequency, or even for identifying of the fluidization regime. It was stated that each configuration, with its own shape and arrangement, can promote or not one or other electrification process by contact, friction or induction and, therefore, each one has a different perception of the flow.

A comparative study of manhole hydraulics using stereoscopic PIV and different RANS models

Flows in manholes are complex and may include swirling and recirculation flow with significant turbulence and vorticity. However, how these complex 3D flow patterns could generate different energy losses and so affect flow quantity in the wider sewer network is unknown. In this work, 2D3C stereo Particle Image Velocimetry measurements are made in a surcharged scaled circular manhole. A computational fluid dynamics (CFD) model in OpenFOAM® with four different Reynolds Averaged Navier Stokes (RANS) turbulence model is constructed using a volume of fluid model, to represent flows in this manhole. Velocity profiles and pressure distributions from the models are compared with the experimental data in view of finding the best modelling approach. It was found among four different RANS models that the re-normalization group (RNG) k-ɛ and k-ω shear stress transport (SST) gave a better approximation for velocity and pressure.