Order-disorder phenomena in α -brass - IV. Nature of order and role of atomic mobility

1961 ◽  
Vol 261 (1307) ◽  
pp. 500-515 ◽  
Keyword(s):  
Room Temperature ◽  
Zinc Content ◽  
Continuous Heating ◽  
Zinc Alloy ◽  
Atomic Mobility ◽  
Zinc Alloys ◽  
Copper Zinc ◽  
Rate Of Heating ◽  
The Difference

On continuous heating of slowly cooled specimens of α -brass containing approximately 30, 25 and 20 at. % zinc there is a marked absorption of energy due to disordering. The range of temperature in which this absorption occurs is sensitive to the rate of heating and the zinc content. Similar characteristics are shown by a silver-zinc alloy containing 27 at. % zinc. On heating specimens of α -brass quenched from 600°C an evolution of energy results from the return of order and the rate of this evolution increases with increasing zinc content. However, for the silver-zinc alloy a constant absorption of energy occurs from approximately room temperature. The degree of disorder retained at room temperature in the quenched specimens of α -brass decreases as the zinc content increases and for the silver-zinc alloy the quenched specimen is more ordered at room temperature than a slowly cooled specimen. The influence of composition on the ΔP curves of both slowly cooled and quenched specimens of α -brass is related to the increase in atomic mobility with increase in zinc content. Similarly the difference between the copper-zinc and silver-zinc alloys is due to the higher atomic mobility in the silver-zinc alloy. It is concluded that the absorption of energy observed in the copper-zinc alloys is due to the destruction of short-range order and that the critical temperature is less than 75°C.

Removal of CU2+, ZN2+ and PB2+ by adsorption onto fly ash and fly ash/lime mixing

1999 ◽  
Vol 39 (10-11) ◽  
pp. 239-247 ◽  
Author(s):  
P. Ricou ◽  
I. Lécuyer ◽  
P. Le Cloirec
Keyword(s):  
Fly Ash ◽  
Metal Content ◽  
Design Methodology ◽  
Power Plants ◽  
Room Temperature ◽  
Removal Mechanism ◽  
Copper Zinc ◽  
Experimental Design Methodology ◽  
Influential Parameters

Disposal of a growing amount of fly ash creates environmental problems due to the leachability of their heavy metal content. Elsewhere, desulfurization treatment in power plants induces pollution by their heavy metals. In this paper, removal of Cu, Zn and Pb by fly ash and fly ash/lime mixing was studied. In the first part of the study, isotherms at different pH were carried out at room temperature. Results show increasing removal with increasing pH. In the second part, experimental design methodology was used. The objectives were to determine the influential parameters among the seven studied for adsorption of copper, zinc and lead, then to study their interactions. Results indicate greater removal by using 100 g.l−1 of adsorbent with 20% mass of lime at pH 5. However, the preparation of the adsorbent must be modified to increase the role of lime in the removal mechanism.

scholarly journals Roofing granules with additive of copper-zinc powder having biocidal properties

Vestnik MGSU ◽  
2019 ◽  
pp. 199-206
Author(s):  
Yuriy V. Chervenko ◽  
Alexey S. Almatov ◽  
Victor N. Sokov
Keyword(s):  
Control Sample ◽  
Zinc Content ◽  
Extended Period ◽  
Selective Dissolution ◽  
Algicidal Activity ◽  
Zinc Alloy ◽  
Culture Solution ◽  
Algae Growth ◽  
Algicidal Effect ◽  
Copper Zinc

Introduction. In the world practice, ceramic coated roofing granules with various biocidal (algicidal) additives are used to prevent discoloration of asphalt roofing shingle. The paper propose the application of the selective dissolution of brass process to accelerate the algicidal effect of surface mineral granules. The authors show that incorporating of brass pigment in the color coat of roofing granules provides the desired degree of algae resistance over an extended period of time. Materials and methods. The brass pigment powder was taken as an algicidal additive. Algae resistant granules with the brass pigment were made in Stroymineral plant. Standard AR granules from North America market were taken as a control sample. Algicidal effect was measured by comparison of control sample and manufactured algae retardant granules performance in the 4 weeks quantitative spectrophotometric chlorophyll test. Measurement of an optical density of the liquid culture solution were made to determine the algae growth rates. The measurement was performed in the laboratory for the development of innovative medicines and biotechnologies in MIPT University. Results. The results show that manufactured algae retardant granules displayed level of the algicidal activity which is equal to control sample during the research. It was found that the highest algicidal activity was shown by products manufactured using finely dispersed copper-zinc alloy powder with a zinc content between 15-30 %. Conclusions. The manufactured granules with brass pigment in the color coating reveal ability to inhibit the algae growth.

Photon-Induced X-ray Fluorescence Analysis of Plain Brasses

1976 ◽  
Vol 30 (1) ◽  
pp. 31-33 ◽  
Author(s):  
S. Pandian ◽  
J. J. Labrecque ◽  
I. L. Preiss
Keyword(s):  
Fluorescence Analysis ◽  
Absorption Spectrometry ◽  
Spectrometric Method ◽  
Time Loss ◽  
Fluorescent Intensity ◽  
Zinc Alloys ◽  
X Ray ◽  
Copper Zinc ◽  
The Difference ◽  
Certified Values

An x-ray spectrometric method, using a radioisotopic radiation source, for analyzing plain brasses (binary copper-zinc alloys) has been developed. The alloys are analyzed as such without dissolving them in any solvent. Methods to correct the contribution due to CuKβ to the Kβ intensity, the difference in fluorescent intensity of the two elements under consideration, and the dead time loss are discussed. The configuration of the system is given. The results obtained by the above method are compared with those obtained using atomic absorption spectrometry and with the certified values.

'The Role of the Grain Boundary on the Resistivity of Pb(Fe1/2Nb1/2)O3 at Room Temperature

2002 ◽  
Vol 718 ◽  
Author(s):  
Sang-Bop Lee ◽  
Kwang-Ho Lee ◽  
Hwan Kim
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Sintered Specimen ◽  
Room Temperature Resistivity ◽  
Boundary Properties ◽  
Order Of Magnitude ◽  
The Difference ◽  
Fe Reduction ◽  
Temperature Resistivity

AbstractThe effect of changing sintering temperature on the grain boundary properties and the room temperature resistivity (ρRT) of Pb(Fe1/2Nb1/2)O3 (PFN) was investigated. Monitering the temperature dependence of resistivity showed that the ρRT's of 1050°C and 1150°C-sintered specimen were 1011ΩEcm and 104ΩEcm respectively, but the resistivity above 300°C became nearly identical. The previous model, that the low resistivity of PFN is due to the electron hopping between Fe2+ and Fe3+ driven by the reduction of PFN, couldn't explain this phenomenon, and the reconsideration of the Fe reduction revealed that the difference of electron concentration between the 1050°C and 1150°C-sintered specimen couldn't exceed one order of magnitude. The role of the grain boundary was introduced in order to account for this phenomenon.

Photoreaction of tyrosin-iodinated bacteriorhodopsin at low temperature

1982 ◽  
Vol 2 (11) ◽  
pp. 949-958 ◽  
Author(s):  
Tatsuo Iwasa ◽  
Kazuo Takeda ◽  
Fumio Tokunaga ◽  
Peter S. Scherrer ◽  
Lester Packer
Keyword(s):  
Low Temperature ◽  
Proton Pump ◽  
Photochemical Reaction ◽  
Room Temperature ◽  
Green Light ◽  
Glycerol Solution ◽  
Difference Spectra ◽  
Tyrosine Residues ◽  
The Difference

To elucidate the role of tyrosine residues in the shift of λmax and the light-driven proton pump of bacteriorhodopsin, the photochemical reaction of tyrosine-iodinated bacteriorhodopsin (tyr-mod-bR) was investigated by low-temperature spectrophotometry. After 4–5 of 11 tyrosine residues of bacteriorhodopsin were iodinated, the meta-intermediate of tyr-mod-bR in 75% glycerol solution became so stable that its decay could be observed even at room temperature and it was stable in the dark for several hours at −65°C. Four batho-intermediates were formed by irradiation with green light (500 nm) at −170°C. Like native bacteriorhodopsin, these batho-intermediates were photoreversible at −170°C. Four corresponding meta-intermediates were also formed by irradiation at −60°C. Using the difference spectra between meta-intermediates and tyr-mod-bR, the absorption spectra of four kinds of tyr-mod-bRs, batho-intermediates, and meta-intermediates were estimated. Each was at shorter wavelengths than that of its corresponding type in native bacteriorhodopsin. The results indicate that two or more tyrosine residues have some role in determining color in native bacteriorhodopsin.

Role of the wrist cuff in forearm plethysmography

1991 ◽  
Vol 80 (5) ◽  
pp. 413-417 ◽  
Author(s):  
Jacques Lenders ◽  
Geert-Jan Janssen ◽  
Paul Smits ◽  
Theo Thien
Keyword(s):  
Blood Flow ◽  
Room Temperature ◽  
Forearm Blood Flow ◽  
Large Range ◽  
Cuff Pressure ◽  
Venous Pressure ◽  
Systolic Pressure ◽  
Ambient Temperatures ◽  
The Difference

1. To determine whether a wrist cuff is necessary to measure the forearm blood flow correctly, we studied the effects of wrist cuff inflation to supra-venous and supra-systolic pressure values over a large range of forearm blood flow values: in the basal state, during post-occlusive hyperaemia of the hand, and during heating of the hand with warm air. Eleven healthy men participated, and the study was carried out at two different ambient temperatures of 20 and 25°C. 2. In the basal state, the measured forearm blood flow was lowest with the wrist cuff at supra-systolic pressure. With the wrist cuff at supra-venous pressure the forearm blood flow was also lower than with an uninflated cuff, but only significantly so when the basal forearm blood flow was higher (at a room temperature of 25°C). 3. During post-occlusive hyperaemia, inflating the wrist cuff to supra-systolic pressure produced the lowest forearm blood flow value at both room temperatures. In addition, with the wrist cuff at supra-venous pressure, forearm blood flow values were lower than with the uninflated cuff, but the supra-venous cuff pressure was clearly less efficient in excluding the hand blood flow than the supra-systolic cuff pressure. 4. During heating of the hand, both supra-systolic and supra-venous cuff pressures were effective in excluding the hand blood flow at both room temperatures. The forearm blood flow measured with the wrist cuff at supra-systolic pressure was lower than that measured with the wrist cuff at supra-venous pressure, but the difference was only significant at a room temperature of 20°C. 5. In conclusion, we have demonstrated that a wrist cuff at supra-systolic pressure is most appropriate for the exclusion of the hand circulation in order to measure the forearm blood flow correctly.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

On the Role of Transferrin in 67Ga Uptake by Tumor Cells

1988 ◽  
Vol 27 (04) ◽  
pp. 151-153
Author(s):  
P. Thouvenot ◽  
F. Brunotte ◽  
J. Robert ◽  
L. J. Anghileri
Keyword(s):  
Specific Binding ◽  
Subcellular Fractionation ◽  
Animal Blood ◽  
Tumor Bearing ◽  
Cell Structures ◽  
The Difference ◽  
Sarcoma Cells ◽  
In Vitro Uptake

In vitro uptake of 67Ga-citrate and 59Fe-citrate by DS sarcoma cells in the presence of tumor-bearing animal blood plasma showed a dramatic inhibition of both 67Ga and 59Fe uptakes: about ii/io of 67Ga and 1/5o of the 59Fe are taken up by the cells. Subcellular fractionation appears to indicate no specific binding to cell structures, and the difference of binding seems to be related to the transferrin chelation and transmembrane transport differences

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Speculative Realism and Science Fiction

2017 ◽  
Author(s):  
Brian Willems
Keyword(s):  
Science Fiction ◽  
Identity Formation ◽  
Cormac Mccarthy ◽  
Doris Lessing ◽  
Speculative Realism ◽  
Neil Gaiman ◽  
The World ◽  
The Difference ◽  
Quentin Meillassoux

A human-centred approach to the environment is leading to ecological collapse. One of the ways that speculative realism challenges anthropomorphism is by taking non-human things to be as valid objects of investivation as humans, allowing a more responsible and truthful view of the world to take place. Brian Willems uses a range of science fiction literature that questions anthropomorphism both to develop and challenge this philosophical position. He looks at how nonsense and sense exist together in science fiction, the way in which language is not a guarantee of personhood, the role of vision in relation to identity formation, the difference between metamorphosis and modulation, representations of non-human deaths and the function of plasticity within the Anthropocene. Willems considers the works of Cormac McCarthy, Paolo Bacigalupi, Neil Gaiman, China Miéville, Doris Lessing and Kim Stanley Robinson are considered alongside some of the main figures of speculative materialism including Graham Harman, Quentin Meillassoux and Jane Bennett.

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