Effects of Solidification Parameters on Lamellar Microstructures of Near Eutectic Cr-Cr3Si Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
H. Bei ◽  
E. P. George ◽  
G. M. Pharr
Keyword(s):  
Growth Rates ◽  
Solidification Rate ◽  
High Growth ◽  
Lamellar Spacing ◽  
Growth Conditions ◽  
Limited Range ◽  
Lamellar Structures ◽  
Wide Range ◽  
Solidification Parameters ◽  
Very High

ABSTRACTDirectional solidification of Cr-Cr3Si eutectic alloys has been carried out using a high temperature optical floating zone furnace. Uniform and well-aligned lamellar structures were obtained over a fairly wide range of intermediate growth rates but not at very low or very high growth rates where degenerate and cellular structures, respectively, were obtained. The lamellar spacing was found to increase with decreasing solidification rate, in agreement with the Jackson-Hunt theory. In addition, for a fixed growth rate, the lamellar spacing was found to increase with increasing rotation rate. Lamellar structures could also be produced at off-eutectic compositions, but only for a limited range of growth conditions. The Cr-rich lamellae are effective in stopping indention cracks nucleated in the brittle Cr3Si phase.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

How to optimize lichen relative growth rates in growth cabinets

2016 ◽  
Vol 48 (4) ◽  
pp. 305-310 ◽  
Author(s):  
Yngvar GAUSLAA ◽  
Md Azharul ALAM ◽  
Knut Asbjørn SOLHAUG
Keyword(s):  
Surface Water ◽  
Growth Rates ◽  
Filter Paper ◽  
High Growth ◽  
Growth Chamber ◽  
Lobaria Pulmonaria ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Very High

AbstractIn order to improve growth chamber protocols for lichens, we tested the effect of 1) wet filter paper versus self-drained nets as a substratum for lichens, and 2) gradual versus abrupt transitions between dark and light periods. For Lobaria pulmonaria (L.) Hoffm. cultivated on nets, RGR increased by 60% compared to those on wet papers, whereas abrupt on/off transitions between day/night gave as high growth rates as gradual transitions mimicking sunrise/sunset. Because thalli on nets had less surface water than those on papers, the higher RGR on nets likely resulted from less suprasaturation depression of photosynthesis. By supporting very high growth and eliminating any visible damage, the revised growth chamber protocols facilitate new functional lichen studies.

scholarly journals Kinetic Analysis of Growth Rate, ATP, and Pigmentation Suggests an Energy-Spilling Function for the Pigment Prodigiosin of Serratia marcescens

2008 ◽  
Vol 190 (22) ◽  
pp. 7453-7463 ◽  
Author(s):  
Pryce L. Haddix ◽  
Sarah Jones ◽  
Pratik Patel ◽  
Sarah Burnham ◽  
Kaori Knights ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Serratia Marcescens ◽  
Growth Rates ◽  
High Growth ◽  
Atp Synthesis ◽  
Opportunistic Pathogen ◽  
Growth Conditions ◽  
Atp Production ◽  
Concentration Changes ◽  
Energy Spilling

ABSTRACTSerratia marcescensis a gram-negative environmental bacterium and opportunistic pathogen.S. marcescensexpresses prodigiosin, a bright red and cell-associated pigment which has no known biological function for producing cells. We present here a kinetic model relating cell, ATP, and prodigiosin concentration changes forS. marcescensduring cultivation in batch culture. Cells were grown in a variety of complex broth media at temperatures which either promoted or essentially prevented pigmentation. High growth rates were accompanied by large decreases in cellular prodigiosin concentration; low growth rates were associated with rapid pigmentation. Prodigiosin was induced most strongly during limited growth as the population transitioned to stationary phase, suggesting a negative effect of this pigment on biomass production. Mathematically, the combined rate of formation of biomass and bioenergy (as ATP) was shown to be equivalent to the rate of prodigiosin production. Studies with cyanide inhibition of both oxidative phosphorylation and pigment production indicated that rates of biomass and net ATP synthesis were actually higher in the presence of cyanide, further suggesting a negative regulatory role for prodigiosin in cell and energy production under aerobic growth conditions. Considered in the context of the literature, these results suggest that prodigiosin reduces ATP production by a process termed energy spilling. This process may protect the cell by limiting production of reactive oxygen compounds. Other possible functions for prodigiosin as a mediator of cell death at population stationary phase are discussed.

Semicentralised supply and treatment systems: integrated infrastructure solutions for fast growing urban areas

2010 ◽  
Vol 61 (11) ◽  
pp. 2905-2913 ◽  
Author(s):  
S. Bieker ◽  
P. Cornel ◽  
M. Wagner
Keyword(s):  
Growth Rates ◽  
Urban Areas ◽  
Water Reuse ◽  
High Growth ◽  
World Population ◽  
Private Households ◽  
Water Demands ◽  
Wide Range ◽  
Water Supply And Treatment ◽  
Treatment And Disposal

Currently, the development of the world population is characterised by two trends: absolute population growth and rapid urbanisation. Especially rapid urbanisation, taking place in Asia, Latin America and Africa, poses major pressure on the affected regions. The development of e.g. Asian countries today is stamped by a combination of urbanisation with high economic growth rates. Conventional centralised infrastructure of supply, treatment and disposal of water is not able to cope with the new challenges arising from these, in history incomparable, high growth rates. Therefore new approaches to infrastructure supply and treatment systems are required – for ecological, sociocultural and economic reasons. The semicentralised approach, focusing on integrated water supply and treatment structures for wastewater and waste on the neighbourhood level, offers one possible solution to the challenges imposed by rapid urbanisation and growing resource needs. The change from centralised to semicentralised supply and treatment systems will minimise the grave discrepancy between the rapid urban growth and the provision of supply and treatment infrastructure. Integrated semicentralised supply and treatment systems face the challenge of growing amounts of wastewater and solid waste combined with rising needs of water for private households and industrial use. The semicentralised approach offers a wide range of flexibility in implementation, energy self-sufficient operation, enormous saving potentials in water demands through intra-urban water reuse and further more advantages in comparison to centralised sectored solutions as practised today.

Versatile High Rate Plasma Deposition and Processing with very high Frequency Excitation

1997 ◽  
Vol 467 ◽  
Author(s):  
M. Heintze
Keyword(s):  
Growth Rates ◽  
High Frequency ◽  
Plasma Deposition ◽  
Excitation Frequency ◽  
High Growth ◽  
Surface Reactivity ◽  
High Rate ◽  
Plasma Diagnostic ◽  
Very High Frequency ◽  
Very High

ABSTRACTThe interest in plasma deposition using very high frequency (VHF) excitation arose after the preparation of a-Si:H at high growth rates was demonstrated. Subsequently the improved process flexibility and the control of material properties offered by the variation of the plasma excitation frequency was recognized. The preparation of amorphous and microcrystalline thin films in a VHF-plasma is described. The increased growth rates have been attributed to an enhancement of film precursor formation at VHF, to the decreased sheath thickness as well as to an enhancement of the surface reactivity by positive ions. Plasma diagnostic investigations show that the parameters mainly affected by the excitation frequency are the ion flux to the electrodes as well as the sheaths potentials and widths, rather than the plasma density.

scholarly journals Hydrogenated amorphous silicon deposited at very high growth rates by an expanding Ar–H2–SiH4 plasma

2001 ◽  
Vol 89 (4) ◽  
pp. 2404-2413 ◽  
Author(s):  
W. M. M. Kessels ◽  
R. J. Severens ◽  
A. H. M. Smets ◽  
B. A. Korevaar ◽  
G. J. Adriaenssens ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Growth Rates ◽  
Hydrogenated Amorphous Silicon ◽  
High Growth ◽  
Hydrogenated Amorphous ◽  
Very High

scholarly journals Achieving high mobility ZnO : Al at very high growth rates by dc filtered cathodic arc deposition

2011 ◽  
Vol 44 (23) ◽  
pp. 232003 ◽  
Author(s):  
R J Mendelsberg ◽  
S H N Lim ◽  
Y K Zhu ◽  
J Wallig ◽  
D J Milliron ◽  
...  
Keyword(s):  
Growth Rates ◽  
High Mobility ◽  
High Growth ◽  
Cathodic Arc Deposition ◽  
Cathodic Arc ◽  
Arc Deposition ◽  
Very High

TEM study of boron additions to cobalt aluminide

1988 ◽  
Vol 46 ◽  
pp. 546-547
Author(s):  
Gerald B. Feldewerth
Keyword(s):  
High Temperature ◽  
Turbine Engines ◽  
Major Drawback ◽  
University Of Missouri ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Wide Range ◽  
Ordered Alloys ◽  
The University ◽  
Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

Features of the Christian values ​​system

2004 ◽  
pp. 21-29
Author(s):  
G.V. Pyrog
Keyword(s):  
Public Opinion ◽  
Religious Beliefs ◽  
Religious Values ◽  
Direct Influence ◽  
Moral Norms ◽  
Value System ◽  
Christian Religion ◽  
Mass Consciousness ◽  
Wide Range ◽  
Very High

In domestic scientific and public opinion, interest in religion as a new worldview paradigm is very high. Today's attention to the Christian religion in our society is connected, in our opinion, with the specificity of its value system, which distinguishes it from other forms of consciousness: the idea of ​​God, the absolute, the eternity of moral norms. That is why its historical forms do not receive accurate characteristics and do not matter in the mass consciousness. Modern religious beliefs do not always arise as a result of the direct influence of church preaching. The emerging religious values ​​are absorbed in a wide range of philosophical, artistic, ethical ideas, acting as a compensation for what is generally defined as spirituality. At the same time, the appeal to Christian values ​​became very popular.

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