Hydrogen Diffusivity and Solubility in Pd Alloys Containing Nanometric Oxides

2009 ◽  
Vol 7 ◽  
pp. 81-86
Author(s):  
Viviane M. Azambuja ◽  
Dílson S. dos Santos ◽  
Daniel Fruchart
Keyword(s):  
Internal Oxidation ◽  
Cold Working ◽  
Hydrogen Permeation ◽  
The Other ◽  
Hydrogen Solubility ◽  
Hydrogen Diffusivity ◽  
Other Hand ◽  
Heat Treated ◽  
Cold Worked

. The Pd0.97Zr0.03, Pd0.97Ce0.03 and Pd0.97Ce0.015 Zr0.015 alloys were produced and studied in the present paper with respect to the hydrogen diffusivity and solubility. These alloys in the conditions as melted and cold worked, heat treated and also internally oxidized were submitted to hydrogen permeation tests. It was observed that the hydrogen diffusivity is strongly affected by the internal oxidation due to nano-oxides formation in the samples. On the other hand, the hydrogen solubility increases with introduction of defects as dislocations and vacancies introduced by cold working as well as the precipitates due to the internal oxidation. The nature, size and distribution of the precipitates and their influence on the hydrogen permeation parameters are discussed in this work.

scholarly journals Propagation of Selected Pear and Quince Rootstocks By Hardwood Cuttings

2016 ◽  
Vol 64 (4) ◽  
pp. 1211-1217 ◽  
Author(s):  
Tomáš Nečas ◽  
Luděk Laňar ◽  
Ivo Ondrášek ◽  
Jan Náměstek ◽  
Jakub Láčík ◽  
...  
Keyword(s):  
Ethanol Solution ◽  
The Other ◽  
Naphthalene Acetic Acid ◽  
Rooted Cuttings ◽  
Beneficial Effects ◽  
Heat Stimulation ◽  
Other Hand ◽  
Heat Treated ◽  
The Difference ◽  
Made In

As long as new rootstocks continue to be developed, there will always the need for new genotypes to be controlled and evaluated. This study involves verification of selected rootstocks with reference to growth, propagation ability and other characteristics. Different rootstocks, different growth stimulators and different kinds of cuttings techniques were adopted for these experiments. Stimulators used for evaluations included: 1 % Racine (2.5 % naphthalene acetic acid - NAA), 0.5 % Rhizopon AA (2.5 % indole-3-butyric acid - IBA) and 0.25 % IBA in 50 % ethanol solution. There were three sets of experiments in all. In Experiment 1, the bases of cuttings were treated with the stimulators and part of them was also treated with heat before planting. Results from Experiment 1 indicated that cuttings treated with Rhizopon AA produced the best effect after heat treatment (with an overall average of 36.9 % of rooted cuttings). Pyrodwarf (78.7 %), Cydomalus (73.9 %) and Pyroplus (60.6 %) were the best performing rootstocks among the evaluated ones. In Experiment 2, we evaluated the influence of the date of harvesting the cuttings on rooting (comparisons were made between cuttings prepared in December [early] and March [late]). For BA29 rootstock cuttings, the best performance was attained by cuttings taken in March. The difference in rooting between March and December was 43.9 %. On the other hand, early harvested rootstocks (cuttings taken in December) for Cydomalus showed the best performance, with an 18.7 % difference between cuttings made in December and in March. Results from other evaluated rootstocks were not significant enough. In Experiment 3, the effect of chemical (phytohormone) stimulation and heat stimulations was compared. The best result was obtained by combinations of treatments without heat stimulations, when the cuttings were stored at 5°C and later treated with 0.25 % IBA in 50 % ethanol solution. The least rooting results, on the other hand, were observed in heat treated cuttings, in cuttings stimulated with IBA and subsequently with heat and in cuttings treated with a 3 cm radial cut at the base. Based on our findings we cannot prove clearly that heat stimulation and the phytohormones used have beneficial effects on rooting of especially new rootstock genotypes with an unknown propagation coefficient. This means that propagation using cuttings still remains an interesting topic to be further researched.

A Feasibility Study on Advanced Methodology to Produce High-Performance Nano WC-Co Granule Feedstock for Thermal Spraying

2005 ◽  
Vol 475-479 ◽  
pp. 2891-2894
Author(s):  
H.W. Jun ◽  
Hyun Kwang Seok ◽  
Joo Sun Kim ◽  
Hai Won Lee
Keyword(s):  
Spray Drying ◽  
Feasibility Study ◽  
High Performance ◽  
Thermal Spraying ◽  
The Other ◽  
Other Hand ◽  
Heat Treated ◽  
Morphological Defects ◽  
Spraying Process

A feasibility study was conducted, in order to fabricate WC-Co powder granule as high-performance feedstock for thermal spraying process, by spray drying weakly flocculated nano-particulate slurries under various conditions. The defects were evaluated with respect to the amount of additives to prepare spherical WC-Co feedstock powders with few morphological defects and homogeneous microstructures. The characteristics of feedstock powders heat-treated at 850~ 1200ı were analyzed using SEM, EPMA, and Hg-porosimetry. The microstructure investigation revealed that the relative portion of larger pores around 10 µm increased with increasing heattreatment temperature. On the other hand, the relative portion of smaller pores of 1 µm decreased due to the coalescence of WC particles, leading to dense feedstock powders with less defects such as hollow or craters. The hardness of thermal-sprayed coat developed with the feedstock in this study, which had exceptionally high feedstock strength, was superior to that of any other sprayed coat obtained with commercial feedstock powders.

Effect of Titanium on Microstructure of Al2014 Alloy Prepared by SIMA Process

2013 ◽  
Vol 553 ◽  
pp. 93-98 ◽  
Author(s):  
M. Amuei ◽  
M. Emamy ◽  
R. Khorshidi
Keyword(s):  
Grain Size ◽  
Cold Working ◽  
Titanium Content ◽  
Optimum Amount ◽  
Globular Structure ◽  
Globular Microstructure ◽  
Heat Treated ◽  
Sima Process ◽  
Cold Worked ◽  
Semi Solid

Forming in semi-solid state to achieve globular microstructure has an effective influence on mechanical properties of aluminum alloys. In this research, the Al2014 alloy was prepared by a semi-solid strain-induced melt activated (SIMA) process. In order to analyze the effect of titanium content on the macrostructure of Al2014, the optimum amount of titanium according to its efficiency on reducing the grain size was obtained. Then, specimens with optimum titanium content were prepared by the SIMA process. Cold working was applied on specimens by an upsetting technique. Cold worked specimens were heat treated at 595, 605, 615, 625 and 635°C and were kept at these temperatures for 30 min to achieve a globular structure. Observations through optical and scanning electron microscopy (SEM) revealed that by increasing the temperature, an increase in sphericity and grain size occurs. According to the results, optimum condition in order to achieve a fine and globular microstructure is keeping specimens at 625°C for 30 min.

Improvement of Mechanical Properties by Two-Step Aging in Ultrafine Grained Al-Ag-Sc Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 857-863
Author(s):  
Daisuke Terada ◽  
Yan Zeng ◽  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Tensile Elongation ◽  
The Other ◽  
Al Alloy ◽  
Other Hand ◽  
Heat Treated ◽  
Ultrafine Grained ◽  
The Matrix ◽  
The Difference

In order to improve limited ductility of ultrafine grained (UFG) Al alloys, mechanical properties of an UFG Al alloy having fine precipitates within grains were investigated. An Al-0.2wt%Sc-4.2wt%Ag alloy was severely deformed by the ARB process at room temperature and subsequently heat-treated by a two-step aging. After the first aging in the two-step aging, fine Al3Sc precipitates were formed. In the specimen ARB processed by 4cycles, the fine Al3Sc precipitates were homogeneously dispersed within the grains. On the other hand, in the specimen ARB processed by 8 cycles, Al3Sc precipitates were linearly-aligned on the grain boundaries that had moved during the heat treatment. After the second aging, fine G.P. zones of Ag as well as Ag2Al precipitates were observed within the grains in the specimen ARB processed by 4 cycles. Coarse precipitates of Ag2Al at grain boundaries were observed in the specimen ARB processed by 8 cycles. The difference in the distribution of precipitates was considered to be due to the difference in fraction of high angle grain boundaries in the matrix microstructures. The strength of the solution treated specimen increased by the two-step aging while the tensile elongation decreased. On the other hand, both of the strength and elongation of the specimen ARB processed by 4 cycles increased after the two-step aging. In case of the specimen ARB processed by 8 cycles, the strength decreased slightly and the elongation increased by the two-step aging, and the aged specimen exhibited a good balance between strength and elongation.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

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