scholarly journals THE INFLUENCE OF EXTERNAL FORCES ON THE CHARACTERISTICS OF HARDENING AND THE CHARACTER OF CONVECTIVE FLOWS DURING THE CURING OF INGOTS

2021 ◽  
pp. 56-62
Author(s):  
A. Ya. Puzikov ◽  
S. B. Gamanuk ◽  
N. A. Zyuban ◽  
D. V. Rutskiy ◽  
K. A. Ivchenko
Keyword(s):  
Solid Phase ◽  
Convective Motion ◽  
Solidification Process ◽  
The Body ◽  
Axial Zone ◽  
Convective Flows ◽  
External Influences ◽  
External Forces ◽  
Structural Zones

The paper describes the influence of external influences on the features and nature of convective flows during the solidification of ingots. It is shown that topping up the profitable part of the ingot with hot portions of the melt changes the nature of the convective motion of the melt in the body of the model ingot. Laminar movement is observed before refilling, after turbulent. The change in the nature of the movement of the liquid in the body of the ingot contributes to an increase in the speed of the front of the solid phase, as evidenced by the results of calculating the rate of solidification throughout the solidification process of the model ingot. The analysis of the structural zones showed an increase in the zone of columnar crystals from 58.6% to 72.3% and the zone of the deposition cone, from 6.5% to 9.1% in refilled ingots compared to the classic ingot. There is also a decrease in the zone of differently oriented crystals from 26.8 to 13.7% and the crustal zone from 5.9% to 2.8%. The length of the axial zone increased from 36 to 54%, with a decrease in its diameter from 6.5 to 5.1%.

The Supersonic Flow Past a Slender Ducted Body of Revolution with an Annular Intake

1950 ◽  
Vol 1 (4) ◽  
pp. 305-318
Author(s):  
G. N. Ward
Keyword(s):  
Supersonic Flow ◽  
Velocity Potential ◽  
Operational Calculus ◽  
The Body ◽  
Body Of Revolution ◽  
Internal Flows ◽  
Flow Past ◽  
External Forces ◽  
Internal Pressures ◽  
Slender Body Of Revolution

SummaryThe approximate supersonic flow past a slender ducted body of revolution having an annular intake is determined by using the Heaviside operational calculus applied to the linearised equation for the velocity potential. It is assumed that the external and internal flows are independent. The pressures on the body are integrated to find the drag, lift and moment coefficients of the external forces. The lift and moment coefficients have the same values as for a slender body of revolution without an intake, but the formula for the drag has extra terms given in equations (32) and (56). Under extra assumptions, the lift force due to the internal pressures is estimated. The results are applicable to propulsive ducts working under the specified condition of no “ spill-over “ at the intake.

scholarly journals Thermal Energy Storage Performance of Tetrabutylammonium Acrylate Hydrate as Phase Change Materials

2021 ◽  
Vol 11 (11) ◽  
pp. 4848
Author(s):  
Hitoshi Kiyokawa ◽  
Hiroki Tokutomi ◽  
Shinichi Ishida ◽  
Hiroaki Nishi ◽  
Ryo Ohmura
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Solid Phase ◽  
Agitation Rate ◽  
Mechanical Agitation ◽  
External Forces

Kinetic characteristics of thermal energy storage (TES) using tetrabutylammonium acrylate (TBAAc) hydrate were experimentally evaluated for practical use as PCMs. Mechanical agitation or ultrasonic vibration was added to detach the hydrate adhesion on the heat exchanger, which could be a thermal resistance. The effect of the external forces also was evaluated by changing their rotation rate and frequency. When the agitation rate was 600 rpm, the system achieved TES density of 140 MJ/m3 in 2.9 hours. This value is comparable to the ideal performance of ice TES when its solid phase fraction is 45%. UA/V (U: thermal transfer coefficient, A: surface area of the heat exchange coil, V: volume of the TES medium) is known as an index of the ease of heat transfer in a heat exchanger. UA/V obtained in this study was comparable to that of other common heat exchangers, which means the equivalent performance would be available by setting the similar UA/V. In this study, we succeeded in obtaining practical data for heat storage by TBAAc hydrate. The data obtained in this study will be a great help for the practical application of hydrate heat storage in the future.

scholarly journals Patient education on back care

2009 ◽  
Vol 65 (1) ◽  
Author(s):  
C. Van Eck
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Patient Education ◽  
Study Design ◽  
Significant Role ◽  
The Body ◽  
Low Back ◽  
Clinical Perspective ◽  
Back Care ◽  
External Forces

Study Design: Clinical PerspectiveObjective: To provide back care education for patients with low back pain. Background:  Understanding the internal and external forces the body issubjected to, as well as the spine’s response to these forces, can better equipphysiotherapists in educating patients with low back pain. Methods and Measures: The focus of the clinical perspective is to providephysiotherapists with clinically sound reasoning when educating patients. Results: Providing a patient handout, educating them in how to incorporate back care knowledge into their dailyactivities.Conclusion: Physiotherapists can play a significant role in empowering patients through education to take responsi-bility for their disability.

The Role of Facial Expressions in the Art of Musical Conducting

2021 ◽  
Vol 66 (2) ◽  
pp. 247-253
Author(s):  
Aurel Muraru
Keyword(s):  
Nonverbal Communication ◽  
Facial Expressions ◽  
The Body ◽  
Large Array ◽  
Level Of Education ◽  
External Influences ◽  
Unitary System ◽  
Accurate Reflection ◽  
Entire Array

"Facial expressions can be regarded as an accurate reflection of the inner emotions people manifest towards the surrounding reality, filtered through their own emotional „strainer”. The source of these feelings lies not only in external influences, but also in a man's own thoughts, experiences, level of education and culture, as well as the degree of development of their own volitional and emotional capacities, in which muscle movements are merely just a simple mechanical means of rendering. The entire array of facial expressions acts as a unitary system which does nothing but complete the movements of the conductor's hands, filling them with meaning. We can say that this type of communication represents a way of combining the most delicate, vibrant, profound, and subtle feelings. It would be impossible to imagine that the movement of the arms, unsupported by the expression of the eyes and face or by the position of the body, were able to express a large array of emotions (joy, pain, sadness, rage, fear, surprise, or confidence) accurately and unequivocally. Keywords: facial expressions, mimicry, nonverbal communication, conductor, performance. "

Tibetan Longevity Meditation

2016 ◽  
Author(s):  
Geoffrey Samuel
Keyword(s):  
World View ◽  
Tibetan Buddhism ◽  
Good Health ◽  
The Body ◽  
Breathing Techniques ◽  
Long Life ◽  
External Forces ◽  
Tantric Practice

The central aim of Tantric practice in Tibetan Buddhism is enlightenment, but the same techniques are also used to attain good health and a long life. The image of the Tantric deity and the surrounding mandala enables the imaginative recreation of a universe in which body-mind and wider environment are connected. Along with mantra recitation, secret breathing techniques, sometimes sexualized visualizations, and various movements and postures, this is understood to help the person reabsorb various kinds of life-essence that have been lost to the environment. Technique and culture are intertwined, since the practices are based on a ‘shamanic’ world-view in which life-essence may be lost to external forces, and the body-mind complex restored to good health and functioning through their recovery.

scholarly journals Physiological Responses of Jurkat Lymphocytes to Simulated Microgravity Conditions

2019 ◽  
Vol 20 (8) ◽  
pp. 1892 ◽  
Author(s):  
Caterina Morabito ◽  
Paola Lanuti ◽  
Giusy A. Caprara ◽  
Marco Marchisio ◽  
Mariano Bizzarri ◽  
...  
Keyword(s):  
Simulated Microgravity ◽  
Immune Cell ◽  
Cellular Level ◽  
The Body ◽  
Jurkat Cells ◽  
Cell Phenotype ◽  
Environmental Condition ◽  
Mitochondria Membrane Potential ◽  
Microgravity Conditions ◽  
External Forces

The presence of microgravity conditions deeply affects the human body functions at the systemic, organ and cellular levels. This study aimed to investigate the effects induced by simulated-microgravity on non-stimulated Jurkat lymphocytes, an immune cell phenotype considered as a biosensor of the body responses, in order to depict at the cellular level the effects of such a peculiar condition. Jurkat cells were grown at 1 g or on random positioning machine simulating microgravity. On these cells we performed: morphological, cell cycle and proliferation analyses using cytofluorimetric and staining protocols—intracellular Ca2+, reactive oxygen species (ROS), mitochondria membrane potential and O2− measurements using fluorescent probes—aconitase and mitochondria activity, glucose and lactate content using colorimetric assays. After the first exposure days, the cells showed a more homogeneous roundish shape, an increased proliferation rate, metabolic and detoxifying activity resulted in decreased intracellular Ca2+ and ROS. In the late exposure time, the cells adapted to the new environmental condition. Our non-activated proliferating Jurkat cells, even if responsive to altered external forces, adapted to the new environmental condition showing a healthy status. In order to define the cellular mechanism(s) triggered by microgravity, developing standardized experimental approaches and controlled cell culture and simulator conditions is strongly recommended.

Lower Bounds to the Critical Rayleigh Number in Completely Confined Regions

1967 ◽  
Vol 34 (2) ◽  
pp. 308-312 ◽  
Author(s):  
M. Sherman ◽  
S. Ostrach
Keyword(s):  
Rayleigh Number ◽  
Lower Bounds ◽  
Body Force ◽  
Critical Rayleigh Number ◽  
Convective Motion ◽  
The Body ◽  
Maximum Dimension ◽  
Fixed Temperature ◽  
Boussinesq Fluid ◽  
The Given

A method is presented for estimating lower bounds to the minimum Rayleigh number that will induce a state of convective motion in a quasi-incompressible (Boussinesq) fluid where the temperature gradient is in the direction of the body force. The fluid is completely confined by fixed-temperature, rigid bounding walls. For any arbitrary region, the critical Rayleigh number is greater than 1558(h/D)4 where h is the maximum dimension of the given region in the direction of the body force and D is the diameter of an equal volume sphere. In certain simple geometrical configurations, improved lower-bound estimates are calculated.

Thermally Responsive Structures for Gastric Pacing and Other Applications

2010 ◽  
Author(s):  
Naga S. Korivi ◽  
Charles Halliburton ◽  
Pratul K. Ajmera
Keyword(s):  
Body Temperature ◽  
Solid Phase ◽  
Polymer Structure ◽  
Important Application ◽  
The Body ◽  
Channel Network ◽  
Gastric Pacing ◽  
Thermally Responsive ◽  
Responsive Polymer ◽  
Polymeric Layer

We report on the development of a polymeric layer consisting of an embedded channel network. The channels are filled with a thermally responsive polymer. The embedded thermally responsive polymer is in solid phase in room ambient, but changes to liquid at physiological body temperature (∼37 °C). This phase change results in the polymer structure changing to a more flexible state. An important application of this polymer layer is its use as a thermally regulated support structure for a gastric pacing electrode, to give some rigidity to the electrode body preferable during implantation surgery, while changing to a more flexible state inside the body as the embedded polymer subsequently melts at physiological temperature. The latter is expected to reduce complications caused by a rigid device.

Improvement of Grain-Growth and Surface Roughness in Laser-Crystallized Polycrystalline Silicon Films

1997 ◽  
Vol 472 ◽  
Author(s):  
H.-S. Choi ◽  
C.-M. Park ◽  
J.-H. Jeon ◽  
B.-H. Min ◽  
M.-K. Han
Keyword(s):  
Surface Roughness ◽  
Grain Growth ◽  
Polycrystalline Silicon ◽  
Treatment Time ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solidification Process ◽  
Laser Crystallization ◽  
Sem Images ◽  
Radical Treatment

ABSTRACTThe effects of nitrogen-radical treated amorphous silicon (a-Si) films on laser-crystallization behavior have been studied for the improvement of the grain-growth and the surface roughness. The radical treatments were performed by the rf (13.56 MHz) plasma-enhanced-chemical-vapor-deposition (PECVD) system with N2 gas before the laser-crystallization. The grain-size of the laser-crystallized polycrystalline silicon (poly-Si) film with 600 seconds of radical-treatment time was remarkably increased by the relaxation of solidification process caused by the possible evolution of solid phase SiNx compounds which shows the low thermal conductivity. The electrical conductivity at 30 °C was rather lager value of 3×10-5 Ω-1cm-1 than 1×10-5 Ω-1cm-1 of poly-Si without radical treatment, while the highly resistive SiNx compounds were formed. From the SEM images, the surface roughness was also improved by the selective etching of the 5%-water-diluted hydrofluoric (HF) acid on the grain boundaries which the SiNx compounds were well segregated into during the laser-crystallization.

High P-T experimental metasomatism of a fluorapatite with significant britholite and fluorellestadite components: implications for LREE mobility during granulite-facies metamorphism

2003 ◽  
Vol 67 (1) ◽  
pp. 61-72 ◽  
Author(s):  
D. E. Harlov ◽  
H.-J. Förster ◽  
C. Schmidt
Keyword(s):  
Solid Phase ◽  
Granulite Facies ◽  
The Body ◽  
High Contrast ◽  
Substitution Reactions ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
Coupled Substitution ◽  
Local Dissolution ◽  
Strong Depletion

AbstractA LREE-, Si-, S-enriched fluorapatite with ∼7.7 wt.% LREE2O3, 5.3 wt.% SiO2 and 3.5 wt.% SO3 from the Mushugai-Khuduk REE deposit, southern Mongolia, has been experimentally metasomatized in pure H2O at 900°C and 1000 MPa. Despite the high LREE content, inclusions or rim grains of monazite did not form during fluid-induced metasomatism. Under high-contrast BSE imaging, the reacted fluorapatite presents a mottled appearance with light, moderate and dark areas and hosts large fluid inclusions containing anhydrite as the solid phase. Dark areas show moderate depletion in all the LREE. Measurable HREE such as Gd and Y remain unchanged. In the areas of intermediate brightness, Ce and, to a lesser extent, La are moderately enriched relative to the original fluorapatite. In the light areas, Ce and La display strong enrichment, whereas the other LREE, Gd and Y remain little changed. In the dark areas, depletion in LREE is matched by depletion in Si and Na, satisfying the coupled substitution reactions Si4+; + (LREE)3+ = P5+ + Ca2+ and Na+ + (LREE)3+ = 2Ca2+. In the light areas, enrichment in LREE and P is accompanied by depletion in Si, Na and S, implying operation of two different coupled substitution reactions, namely: 2P5+ = Si4+ + S6+ and 2P5+ + LREE3+ = 2S6+ + Na+. In all areas, strong enrichment in F is accompanied by strong depletion in Cl and OH. The formation of large, fluid and anhydrite-filled inclusions associated with the LREE-enriched light areas is evidence of a negative volume change, combined with additional local dissolution of the fluorapatite. This occurred during the metasomatism of the original Cl- and OH-bearing fluorapatite to a nearly pure end-member fluorapatite. Local dissolution of fluorapatite in the space now occupied by the voids, combined with element remobilization from the body of the fluorapatite as a whole, provided the Ca and S needed for the formation of anhydrite as well as the P and LREE required for the enrichment of the bright areas.

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