scholarly journals Asymmetry of the latent heat signature in b-axis oriented single crystal Gd5Si2Ge2

2011 ◽  
Vol 1310 ◽  
Author(s):  
K. Morrison ◽  
V.K. Pecharsky ◽  
K.A. Gschneidner ◽  
L.F. Cohen
Keyword(s):  
Single Crystal ◽  
Latent Heat ◽  
Entropy Change ◽  
Second Phase ◽  
Hall Probe ◽  
Field Sweep ◽  
Sweep Direction ◽  
The Difference ◽  
Nucleation Size ◽  
Oriented Single Crystal

ABSTRACTA 100 micron fragment of a b-axis oriented single crystal Gd5Si2Ge2 has been studied using microcalorimetry, enabling the separate measurement of the heat capacity and the latent heat. The sample was taken from the same crystal previously studied with Hall probe imaging, which showed that the phase transition is seeded by a second phase of Gd5Si1.5Ge1.5 nanoplatelets on the increasing field sweep direction only. The multiple transition features observed in the latent heat signature suggests a nucleation size of approximately 20 μm, consistent with the lengthscale suggested by Hall imaging. The difference in nucleation and growth process with field sweep direction is clearly identified in the latent heat. We show that the latent heat contribution to the entropy change is of the order of 50% of the total entropy change and unlike other systems studied, the transition does not broaden (and the latent heat contribution does not diminish significantly) as magnetic field and temperature are increased within the parameter range explored in these experiments.

scholarly journals Generalization of intrinsic ductile-to-brittle criteria by Pugh and Pettifor for materials with a cubic crystal structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
O. N. Senkov ◽  
D. B. Miracle
Keyword(s):  
Crystal Structure ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Single Crystal ◽  
Elastic Constants ◽  
Mechanical Analysis ◽  
Quantum Mechanical ◽  
Modulus Ratio ◽  
Cubic Crystal ◽  
The Difference

AbstractTwo classical criteria, by Pugh and Pettifor, have been widely used by metallurgists to predict whether a material will be brittle or ductile. A phenomenological correlation by Pugh between metal brittleness and its shear modulus to bulk modulus ratio was established more than 60 years ago. Nearly four decades later Pettifor conducted a quantum mechanical analysis of bond hybridization in a series of intermetallics and derived a separate ductility criterion based on the difference between two single-crystal elastic constants, C12–C44. In this paper, we discover the link between these two criteria and show that they are identical for materials with cubic crystal structures.

Effect of grain boundaries in La0.84Sr0.16CoO3−δ on oxygen diffusivity and surface exchange kinetics

2021 ◽  
Author(s):  
Natalia Porotnikova ◽  
Andrei Farlenkov ◽  
Sergey Naumov ◽  
Maxim Vlasov ◽  
Anna Khodimchuk ◽  
...  
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Gas Phase ◽  
Oxygen Exchange ◽  
Polycrystalline Specimen ◽  
Surface Exchange ◽  
Oxygen Diffusivity ◽  
Exchange Kinetics ◽  
Oriented Single Crystal

The 16O/18O oxygen exchange kinetics between the gas phase and the oriented single crystal and polycrystalline specimen has been studied; the rates of individual stages of oxygen exchange have been calculated and discussed.

Electronic irradiation of TlInSxSe2−x (x = 1): Morphology, structure and raman scattering

2021 ◽  
Author(s):  
M. Yu. Tashmetov ◽  
F. K. Khallokov ◽  
N. B. Ismatov ◽  
I. I. Yuldashova ◽  
S. Kh. Umarov
Keyword(s):  
Surface Morphology ◽  
Single Crystal ◽  
Single Phase ◽  
Phase State ◽  
Monoclinic Structure ◽  
Average Value ◽  
Single Phase State ◽  
Before And After ◽  
Electronic Irradiation ◽  
The Difference

It is shown that the replacement of a part of sulfur atoms with selenium atoms in a TlInS2 single crystal stimulates the formation of a single-phase state with a monoclinic structure (space group [Formula: see text]/[Formula: see text] in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation with 2 MeV electrons and a fluence of [Formula: see text] electron/cm2 of powder TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) leads to an increase in the crystallite size from 56.5 nm to 65 nm, which is most likely associated with a decrease in the interface. The difference between the surface morphology of the synthesized TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal and the surface morphology of the TlInS2 single crystal is established, which consists in a decrease in the height and width of the roughness in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation of a TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal with electrons with a fluence of [Formula: see text] electron/cm2 does not lead to a change in the height of the tubercle on its surface, and the average value of its width increases more than ten-fold. The identity of the peaks in the Raman spectra of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal before and after its irradiation with electrons with an energy of 2 MeV and upto a fluence of [Formula: see text] electron/cm2, along with the absence of a shift of the peaks, indicates the radiation resistance of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal.

scholarly journals The effect of soybean formula and formula 100 supplementation on the growth of preschool children

2016 ◽  
Vol 45 (6) ◽  
pp. 256
Author(s):  
M Mexitalia ◽  
Yohanes Tri Nugroho ◽  
J C Susanto
Keyword(s):  
Preschool Children ◽  
Body Height ◽  
High Energy ◽  
Second Phase ◽  
Z Score ◽  
Health Food ◽  
Alternative Health ◽  
Second Phases ◽  
The Difference ◽  
Weight For Age

Background Preschool children are vulnerable in growth. Soy-bean formula (SF) and formula-100 (F100) are supplementary foodswhich contain of high energy and are available at low price; how-ever, they are not widely used for preschool children.Objectives To investigate the effect of SF compared to F100 onthe growth of preschool children.Methods A cross-over trial was conducted on 96 preschool chil-dren aged 4-7 years. Subjects were randomly divided into 2 groupswhich received 200 ml soybean formula (n=49) or F100 (n=47) for1 month and crossed-over after a six-week wash-out period. Bodyweight was measured weekly. Body height and food analysis by 3-day food recall were measured at the beginning and the end of thestudy. The criteria of the acceptability of the formula was eithergood or poor.Results Supplementation with SF as well as F100 induced catchup growth as shown by the increase of Δz-score. There were nosignificant difference of Δ weight for age z-score, Δ height for agez-score, and Δ weight for height z score between groups duringthe first and second phases of the trial. The acceptability of F100was significantly better than that of SF at the beginning; neverthe-less, the difference was not significant at the second phase trial.Conclusions Soybean formula and F100 given for a one monthperiod can induce catch-up growth in preschool children. Soybeanformula as an alternative health food can be accepted by preschoolchildren

Effect of Reinforcement of the Negative Discriminandum in Differential Conditioning

1964 ◽  
Vol 14 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Peter J. Donovick ◽  
Leonard E. Ross
Keyword(s):  
Phase I ◽  
Discrimination Learning ◽  
Differential Conditioning ◽  
Discrimination Problem ◽  
Single Stimulus ◽  
Female Rats ◽  
Second Phase ◽  
Learning Situation ◽  
Learning Conditions ◽  
The Difference

The present investigation was concerned with the reduction of inhibition associated with the negative discriminandum in a single stimulus discrimination learning situation. In Phase I 33 female rats were trained on a black-white discrimination problem. In the second phase Ss were divided into three groups which received: (a) 100% reinforcement to both the old positive and negative discriminanda; (b) four trials per day to the old negative, 100% reward; (c) eight trials per day to the old negative, 100% reward. As in previous studies, which employed simultaneous discrimination learning conditions, speed to the old negative remained significantly below speed to the old positive in the second phase. However, unlike the previous results, the difference decreased over trials. No differences were found between the groups that had trials to the old negative cue only, or between these groups and either speed to the old positive or the old negative in the case of the group receiving reward on both cues.

scholarly journals A Nelder–Mead algorithm-based inverse transient analysis for leak detection and sizing in a single pipe

2021 ◽  
Author(s):  
Oussama Choura ◽  
Caterina Capponi ◽  
Silvia Meniconi ◽  
Sami Elaoud ◽  
Bruno Brunone
Keyword(s):  
Transient Analysis ◽  
Experimental Tests ◽  
Leak Detection ◽  
Calibration Procedure ◽  
Second Phase ◽  
Viscoelastic Parameters ◽  
The Difference ◽  
Single Pipe ◽  
The University ◽  
Nelder Mead Algorithm

Abstract In this paper the results of an experimental validation of a technique for leak detection in polymeric pipes based on the inverse transient analysis (ITA) are presented. In the proposed ITA the Nelder–Mead algorithm is used as a calibration tool. Experimental tests have been carried out in an intact and leaky high-density polyethylene (HDPE) single pipe installed at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy. Transients have been generated by the fast and complete closure of a valve placed at the downstream end section of the pipe. In the first phase of the calibration procedure, the proposed algorithm has been used to estimate both the viscoelastic parameters of a generalized Kelvin–Voigt model and the unsteady-state friction coefficient, by minimizing the difference between the numerical and experimental results. In the second phase of the procedure, the calibrated model allowed the evaluation of leak size and location with an acceptable accuracy. Precisely, in terms of leak location the relative error was smaller than 5%.

scholarly journals Biphasic pattern in the effect of severe measles infection; the difference between additive and multiplicative scale

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nhat Thanh Hoang Le ◽  
Nhan Thi Ho ◽  
Bryan Grenfell ◽  
Stephen Baker ◽  
Ronald B. Geskus
Keyword(s):  
Infectious Diseases ◽  
Hospital Admission ◽  
Measles Virus ◽  
Hospital Admissions ◽  
Admission Rate ◽  
Second Phase ◽  
Before And After ◽  
The Difference ◽  
Two Phases ◽  
Additive Scale

Abstract Background Infection with measles virus (MeV) causes immunosuppression and increased susceptibility to other infectious diseases. Only few studies reported a duration of immunosuppression, with varying results. We investigated the effect of immunosuppression on the incidence of hospital admissions for infectious diseases in Vietnamese children. Methods We used retrospective data (2005 to 2015; N = 4419) from the two pediatric hospitals in Ho Chi Minh City, Vietnam. We compared the age-specific incidence of hospital admission for infectious diseases before and after hospitalization for measles. We fitted a Poisson regression model that included gender, current age, and time since measles to obtain a multiplicative effect measure. Estimates were transformed to the additive scale. Results We observed two phases in the incidence of hospital admission after measles. The first phase started with a fourfold increased rate of admissions during the first month after measles, dropping to a level quite comparable to children of the same age before measles. In the second phase, lasting until at least 6 years after measles, the admission rate decreased further, with values up to 20 times lower than in children of the same age before measles. However, on the additive scale the effect size in the second phase was much smaller than in the first phase. Conclusion The first phase highlights the public health benefits of measles vaccination by preventing measles and immune amnesia. The beneficial second phase is interesting, but its strength strongly depends on the scale. It suggests a complicated interaction between MeV infection and the host immunity.

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