A Solidification Front Monitor for Metal Casting

1998 ◽  
Vol 120 (3) ◽  
pp. 515-522 ◽  
Author(s):  
M. M. Hytros ◽  
J.-H. Chun ◽  
R. C. Lanza ◽  
N. Saka
Keyword(s):  
Solidification Front ◽  
First Generation ◽  
Metal Casting ◽  
Two Phase ◽  
Front Position ◽  
Solid Phases ◽  
Ct System ◽  
Two Phases ◽  
Future Work ◽  
Liquid And Solid Phases

A feasibility study was performed to assess computed tomography (CT) as a method of detecting the position of the solidification front during metal casting. Since the liquid and solid phases of metals differ in density by 4 to 12 percent, CT has the ability to differentiate the two phases. The motivation for this work is the development of a real-time solidification sensor for the continuous casting of metals. A first-generation CT system for reconstructing two-dimensional images of solidifying tin was developed. The performance of the CT system was evaluated by reconstructing images of objects of known geometries. For the solidification experiment, CT scans were conducted on an actively heated and cooled crucible filled with pure tin. The tin existed in both liquid and solid phases, with the solidification front position tracked by thermocouples. The image of the two-phase tin experiment had poor contrast resolution, but a quantitative analysis of the image does indicate an approximate 7 percent difference between the liquid and the solid portions of the melt. However, the size of the liquid phase was not as large as that determined by thermocouple measurements. This is a result of temperature fluctuations in the melt during data acquisition, as well as the relatively low spatial resolution. Future work to improve system performance will include using a linear accelerator (linac) as the radiation source.

scholarly journals Electromagnetic Field as Agent Moving Bioactive Cations. A New Antimicrobial System in Architecture Technology

2021 ◽  
Vol 11 (18) ◽  
pp. 8320
Author(s):  
Andrzej Chlebicki ◽  
Wojciech Spisak ◽  
Marek W. Lorenc ◽  
Lucyna Śliwa ◽  
Konrad Wołowski
Keyword(s):  
Electromagnetic Field ◽  
Cultural Heritage ◽  
Two Phase ◽  
Galvanic Cells ◽  
Solid Phases ◽  
Cultural Heritage Objects ◽  
Liquid And Solid Phases ◽  
Protection Of Cultural Heritage

There is a new described antifungal system (GALVI) involving the moving of bioactive ions of Zn, Cu and Bi for the protection of cultural heritage objects such as buildings, sculptures and stretchers. There were two kinds of galvanic cells that were used: the first composed of a two-electrodes system, Zn, Cu, and second one composed of a three-electrodes system, Zn, Bi and Cu. Moreover, two-phase media are proposed with various kinds of rocks used in architectonical objects. Microorganisms inhabit the boundaries of two liquid and solid phases. This enables the investigation of the process of rock colonization. Possible applications of the suggested GALVI system are mentioned.

Computational Model of Phase Transformations in Thermo-Chemical Cathodes Using Kinetic Approach

2012 ◽  
Vol 510-511 ◽  
pp. 9-14
Author(s):  
A.A. Kavokin ◽  
I.H. Kazmi ◽  
B. Munir
Keyword(s):  
Heat Equation ◽  
Solid Phase ◽  
State Diagram ◽  
Two Phase ◽  
One Dimensional ◽  
Self Similar Solution ◽  
Self Similar ◽  
Solid Phases ◽  
Kinetics Of ◽  
Liquid And Solid Phases

The paper presents the results of modeling of the processes of phases transformations occurring in cathode of plasmatron with zirconium insertion. Model describes temperature and liquid-solid phase transformation in cathode considering kinetics of transformation in accordance with a state diagram. The comparison between one-dimensional mathematical models was exploited for estimation of the kinetics coefficient. First model is based on well-known heat equation with Stefans condition on the free boundary between liquid and solid phases [. The standard analytical self-similar solution for two-phase case is applied. In the second model, for heat equation instead of Stefans conditions, differential equations of kinetics are used.

MULTIPHASE FLOWS IN MAGMATISM

1993 ◽  
Vol 07 (09n10) ◽  
pp. 1997-2023
Author(s):  
TAKEHIRO KOYAGUCHI
Keyword(s):  
Multiphase Flows ◽  
Volcanic Eruptions ◽  
Two Phase ◽  
Porous Flow ◽  
Wide Range ◽  
The Matrix ◽  
Two Phases ◽  
Complex Features ◽  
Matrix Rock ◽  
Liquid And Solid Phases

Diversity of volcanic activities reflects various styles of magma flows. One of the most important characters of the magma flows is that they are composed of gas, liquid and solid phases (multiphase flow). Macroscopic behaviours of multiphase flows are affected by their internal microstructures including the distribution of each phase and the shape of the boundaries between the two phases. Magma segregation from partially molten rock occurs by porous flow being accompanied with compaction of the matrix rock, the macroscopic behaviours of which are governed by microscopic flows of the melt at grain boundaries and deformation of each crystal. The fluctuation of magma effusion at volcanic eruptions is explained by instability of gas-liquid two-phase flow, which depends on motion of each bubble and the ability of bubbles to coalesce. Complex features of pyroclastic flow result from a wide range of grain-size, and hence, variable settling velocities of volcanic fragments within the flow. Physical processes of these multiphase flows in magmatism are reviewed.

A Lightweight Formalism for Reference Lifetimes and Borrowing in Rust

2021 ◽  
Vol 43 (1) ◽  
pp. 1-73
Author(s):  
David J. Pearce
Keyword(s):  
Memory Management ◽  
Programming Model ◽  
Type System ◽  
Control Flow ◽  
Two Phase ◽  
Type Checking ◽  
Strong Focus ◽  
Reference Implementation ◽  
Two Phases ◽  
Complex Features

Rust is a relatively new programming language that has gained significant traction since its v1.0 release in 2015. Rust aims to be a systems language that competes with C/C++. A claimed advantage of Rust is a strong focus on memory safety without garbage collection. This is primarily achieved through two concepts, namely, reference lifetimes and borrowing . Both of these are well-known ideas stemming from the literature on region-based memory management and linearity / uniqueness . Rust brings both of these ideas together to form a coherent programming model. Furthermore, Rust has a strong focus on stack-allocated data and, like C/C++ but unlike Java, permits references to local variables. Type checking in Rust can be viewed as a two-phase process: First, a traditional type checker operates in a flow-insensitive fashion; second, a borrow checker enforces an ownership invariant using a flow-sensitive analysis. In this article, we present a lightweight formalism that captures these two phases using a flow-sensitive type system that enforces “ type and borrow safety .” In particular, programs that are type and borrow safe will not attempt to dereference dangling pointers. Our calculus core captures many aspects of Rust, including copy- and move-semantics, mutable borrowing, reborrowing, partial moves, and lifetimes. In particular, it remains sufficiently lightweight to be easily digested and understood and, we argue, still captures the salient aspects of reference lifetimes and borrowing. Furthermore, extensions to the core can easily add more complex features (e.g., control-flow, tuples, method invocation). We provide a soundness proof to verify our key claims of the calculus. We also provide a reference implementation in Java with which we have model checked our calculus using over 500B input programs. We have also fuzz tested the Rust compiler using our calculus against 2B programs and, to date, found one confirmed compiler bug and several other possible issues.

scholarly journals XCOVNet: Chest X-ray Image Classification for COVID-19 Early Detection Using Convolutional Neural Networks

2021 ◽  
Author(s):  
Vishu Madaan ◽  
Aditya Roy ◽  
Charu Gupta ◽  
Prateek Agrawal ◽  
Anand Sharma ◽  
...  
Keyword(s):  
Image Classification ◽  
Second Phase ◽  
Two Phase ◽  
X Ray ◽  
The Neural Network ◽  
Rapid Spread ◽  
Chest X Ray ◽  
Polymerase Chain ◽  
Two Phases ◽  
Active Patients

AbstractCOVID-19 (also known as SARS-COV-2) pandemic has spread in the entire world. It is a contagious disease that easily spreads from one person in direct contact to another, classified by experts in five categories: asymptomatic, mild, moderate, severe, and critical. Already more than 66 million people got infected worldwide with more than 22 million active patients as of 5 December 2020 and the rate is accelerating. More than 1.5 million patients (approximately 2.5% of total reported cases) across the world lost their life. In many places, the COVID-19 detection takes place through reverse transcription polymerase chain reaction (RT-PCR) tests which may take longer than 48 h. This is one major reason of its severity and rapid spread. We propose in this paper a two-phase X-ray image classification called XCOVNet for early COVID-19 detection using convolutional neural Networks model. XCOVNet detects COVID-19 infections in chest X-ray patient images in two phases. The first phase pre-processes a dataset of 392 chest X-ray images of which half are COVID-19 positive and half are negative. The second phase trains and tunes the neural network model to achieve a 98.44% accuracy in patient classification.

Kinematic and Dynamic Parameters of a Liquid-Solid Pipe Flow Using DPIV∕Accelerometry

2007 ◽  
Vol 129 (11) ◽  
pp. 1415-1421 ◽  
Author(s):  
Joseph Borowsky ◽  
Timothy Wei
Keyword(s):  
Pipe Flow ◽  
Solid Phase ◽  
Fluid Phase ◽  
Central Moment ◽  
Steady Flows ◽  
Dynamic Parameters ◽  
Two Phase ◽  
Turbulence Structures ◽  
Two Phases ◽  
Flat Profile

An experimental investigation of a two-phase pipe flow was undertaken to study kinematic and dynamic parameters of the fluid and solid phases. To accomplish this, a two-color digital particle image velocimetry and accelerometry (DPIV∕DPIA) methodology was used to measure velocity and acceleration fields of the fluid phase and solid phase simultaneously. The simultaneous, two-color DPIV∕DPIA measurements provided information on the changing characteristics of two-phase flow kinematic and dynamic quantities. Analysis of kinematic terms indicated that turbulence was suppressed due to the presence of the solid phase. Dynamic considerations focused on the second and third central moments of temporal acceleration for both phases. For the condition studied, the distribution across the tube of the second central moment of acceleration indicated a higher value for the solid phase than the fluid phase; both phases had increased values near the wall. The third central moment statistic of acceleration showed a variation between the two phases with the fluid phase having an oscillatory-type profile across the tube and the solid phase having a fairly flat profile. The differences in second and third central moment profiles between the two phases are attributed to the inertia of each particle type and its response to turbulence structures. Analysis of acceleration statistics provides another approach to characterize flow fields and gives some insight into the flow structures, even for steady flows.

Complex investigation of the thermal and electrophysical properties of refractory oxides in the liquid and solid phases

1980 ◽  
Vol 38 (4) ◽  
pp. 333-337
Author(s):  
�. �. Shpil'rain ◽  
D. N. Kagan ◽  
L. S. Barkhatov ◽  
L. I. Zhmakin ◽  
V. V. Koroleva
Keyword(s):  
Electrophysical Properties ◽  
Complex Investigation ◽  
Refractory Oxides ◽  
Solid Phases ◽  
Liquid And Solid Phases

Prediction of Pump Performance Under Air-Water Two-Phase Flow Based on a Bubbly Flow Model

1993 ◽  
Vol 115 (4) ◽  
pp. 781-783 ◽  
Author(s):  
Kiyoshi Minemura ◽  
Tomomi Uchiyama
Keyword(s):  
Two Phase Flow ◽  
Bubbly Flow ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Flow Conditions ◽  
Two Phase ◽  
Performance Change ◽  
Void Fractions ◽  
Two Phases

This paper is concerned with the determination of the performance change in centrifugal pumps operating under two-phase flow conditions using the velocities and void fractions calculated under the assumption of an inviscid bubbly flow with slippage between the two phases. The estimated changes in the theoretical head are confirmed with experiments within the range of bubbly flow regime.

Embedded Two-Phase Cooling of High Flux Electronics via Micro-Enabled Surfaces and Fluid Delivery Systems (FEEDS)

2015 ◽  
Author(s):  
Raphael Mandel ◽  
Serguei Dessiatoun ◽  
Patrick McCluskey ◽  
Michael Ohadi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Saturation Temperature ◽  
Absolute Pressure ◽  
High Flux ◽  
Vapor Quality ◽  
Two Phase ◽  
Fluid Delivery ◽  
Future Work

This work presents the experimental design and testing of a two-phase, embedded manifold-microchannel cooler for cooling of high flux electronics. The ultimate goal of this work is to achieve 0.025 cm2-K/W thermal resistance at 1 kW/cm2 heat flux and evaporator exit vapor qualities at or exceeding 90% at less than 10% absolute pressure drop. While the ultimate goal is to obtain a working two-phase embedded cooler, the system was first tested in single-phase mode to validate system performance via comparison of experimentally measured heat transfer coefficient and pressure drop to the values predicted by CFD simulations. Upon validation, the system was tested in two phase mode using R245fa at 30°C saturation temperature and achieved in excess of 1 kW/cm2 heat flux at 45% vapor quality. Future work will focus on increasing the exit vapor quality as well as use of SiC for the heat transfer surface upon completion of current experiments with Si.

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