7,497 research outputs found
Assessment techniques, database design and software facilities for thermodynamics and diffusion
The purpose of this article is to give a set of recommendations to producers of assessed thermodynamic data, who may be involved in either the critical evaluation of limited chemical systems or the creation and dissemination of larger thermodynamic databases. Also, it is hoped that reviewers and editors of scientific publications in this field will find some of the information useful. Good practice in the assessment process is essential, particularly as datasets from many different sources may be combined together into a single database. With this in mind, we highlight some problems that can arise during the assessment process and we propose a quality assurance procedure. It is worth mentioning at this point, that the provision of reliable assessed thermodynamic data relies heavily on the availability of high quality experimental information. The different software packages for thermodynamics and diffusion are described here only briefly
Workshop on Applications of Phase Diagrams in Metallurgy and Ceramics
A workshop was held to assess the current national and international status of phase diagram determinations and evaluations for alloys, ceramics, and semiconductors; to determine the needs and priorities, especially technological, for phase diagram determinations and evaluations; and to estimate the resources being used and potentially available for phase diagram evaluation. Highlights of the workshop, description of a new poster board design used in the poster sessions, lists of attendees and demonstrations, the program, and descriptions of the presentations are included
Convex hull method for the determination of vapour-liquid equilibria (VLE) phase diagrams for binary and ternary systems
Amieibibama Joseph wishes to thank Petroleum Technology Development Fund (PTDF) for their financial support which has made this research possible.Peer reviewedPostprin
Computational thermodynamics and informational technologies in the field of computer design of materials
Computational thermodynamics and informational technologies in the field of computer desing of materials as well as appliance of CALPHAD method on resolution of thermodynamic problems are presented in this paper
Lead telluride bonding and segmentation study Semiannual phase report, 1 Feb. - 31 Jul. 1969
Thermoelectric system of Cd-Si-Ge, and tungsten diffusion bonded lead tellurid
Experimental study of the Sb-Sn-Zn alloy system
experimental description of the SbSn-Zn system by methods scanning electron microskope and differetial scanning calorimetryexperimentálnà popis ternárnà soustavy Sb-Sn-Zn metodami skenovacà elektronové mikroskopie a diferenčnà skenovacà kalorimetrieexperimental description of the SbSn-Zn system by methods scanning electron microskope and differetial scanning calorimetr
Phenomenology of left-right symmetric dark matter
We present a detailed study of dark matter phenomenology in low-scale
left-right symmetric models. Stability of new fermion or scalar multiplets is
ensured by an accidental matter parity that survives the spontaneous symmetry
breaking of the gauge group by scalar triplets. The relic abundance of these
particles is set by gauge interactions and gives rise to dark matter candidates
with masses above the electroweak scale. Dark matter annihilations are thus
modified by the Sommerfeld effect, not only in the early Universe, but also
today, for instance, in the Center of the Galaxy. Majorana candidates -
triplet, quintuplet, bi-doublet, and bi-triplet - bring only one new parameter
to the model, their mass, and are hence highly testable at colliders and
through astrophysical observations. Scalar candidates - doublet and 7-plet, the
latter being only stable at the renormalizable level - have additional
scalar-scalar interactions that give rise to rich phenomenology. The particles
under discussion share many features with the well-known candidates wino,
Higgsino, inert doublet scalar, sneutrino, and Minimal Dark Matter. In
particular, they all predict a large gamma-ray flux from dark matter
annihilations, which can be searched for with Cherenkov telescopes. We
furthermore discuss models with unequal left-right gauge couplings, , taking the recent experimental hints for a charged gauge boson with 2 TeV
mass as a benchmark point. In this case, the dark matter mass is determined by
the observed relic density.Comment: 32 + 23 pages, 4.5 MB; Minor changes and additional comments. Matches
published versio
Feasibility study to extract iron and chromium from chromium contaminated soils
Chromium contaminated soils, besides being recognized for toxic and hazardous hexavalent chromium, contain high iron concentrations. At some sites, concentrations of iron oxide are higher than 30%. Both iron and chromium in soils have recyclable value provided they can be either concentrated in the oxide form or separated as metal. The concentrated oxide can be used as a substitute for the iron ore. The extracted metal can also be recycled in the steel industry. The objective of this study is to study the feasibility of extracting iron and chromium from soils.
Chromium contaminated soils, can be classified into two groups, one with high iron content having magnetic properties, and the other with low content of iron with no magnetic properties. The extraction of iron and chromium in their oxide forms was conducted using magnetic and gravitational separation techniques. The magnetic separation was found to be better than gravitational separation to concentrate iron and chromium from chromium contaminated soils for the experimental setup. However, the iron content in soil could not be concentrated to as high a level as high grade or processed iron ore, 60-70% iron content.
The reduction of iron oxide to metal can be accomplished at high temperature under the reducing environment. The reduction of iron oxide in soil was quite rapid at temperature higher than 1100°C. The solid carbon was used as a reducing agent for the study of reduction in Thermo-Gravimetric Analyzer. The reduction process was found to be controlled by gasification with the activation energy of 45-55 kcal/mol based on the selected kinetic models. The complete reduction required at least 15% of carbon by weight.
The metal agglomeration and separation occurred when sand was added to soils. The substantial percentage of metal, 15-32 %, was separated from GAR and TPR soils mixed with 15-25% of sand and 15% carbon. The LSP soil mixtures yielded metal separation with sand addition above 20%. Phase and viscosity diagrams were used to explain the metal separation and behavior of the slag. Experimental results demonstrated that iron and chromium can be extracted from chromium contaminated soils found in Hudson County, NJ
Implementation of the Hierarchical Reference Theory for simple one-component fluids
Combining renormalization group theoretical ideas with the integral equation
approach to fluid structure and thermodynamics, the Hierarchical Reference
Theory is known to be successful even in the vicinity of the critical point and
for sub-critical temperatures. We here present a software package independent
of earlier programs for the application of this theory to simple fluids
composed of particles interacting via spherically symmetrical pair potentials,
restricting ourselves to hard sphere reference systems. Using the hard-core
Yukawa potential with z=1.8/sigma for illustration, we discuss our
implementation and the results it yields, paying special attention to the core
condition and emphasizing the decoupling assumption's role.Comment: RevTeX, 16 pages, 2 figures. Minor changes, published versio
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