A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

Isolation and Diagnosis of Fungi from Samples of Spices in the City of Nasiriya

2020 ◽  
pp. 7-9
Keyword(s):  
Chronic Diseases ◽  
Dilution Method ◽  
Local Markets ◽  
White Pepper ◽  
Black And White ◽  
Different Types ◽  
Potential Risks ◽  
The City ◽  
Isolated Species

Examination of (35) samples of spices obtained from local markets for the purposes of isolating and diagnosing fungi growing on them. Anine isolates belonging to 13 different types of fungi were diagnosed by the standard dilution method with three replications, and it has been observed that the most samples from which the fungi were isolated is ginger. It was found that the most isolated species of fungi are Penicillium, Aspergillus, and Rizupes spp. A rare colony of fungi was observed, which indicates contamination of the spices under study with the fungus. The present study aims to identify the potential risks of the presence of fungi in spices and what may result from mycotoxins that may be the cause of many chronic diseases as a result of using these spices in large quantities. The study recommends limiting the use of contaminated spices, especially ginger, in preparing food and its uses, in addition to other types such as cloves, black and white pepper, and other types of spices found in the local markets, especially the expired ones.

Masks and racial stereotypes in a pandemic: the case for surgical masks

2021 ◽  
pp. 1-18
Author(s):  
Leah Christiani ◽  
Christopher J. Clark ◽  
Steven Greene ◽  
Marc J. Hetherington ◽  
Emily M. Wager
Keyword(s):  
Black People ◽  
Racial Bias ◽  
White Male ◽  
Elevated Risk ◽  
Racial Stereotypes ◽  
Black And White ◽  
Surgical Masks ◽  
Racial Resentment ◽  
Different Types ◽  
Male Model

Abstract To contain the spread of COVID-19, experts emphasize the importance of wearing masks. Unfortunately, this practice may put black people at elevated risk for being seen as potential threats by some Americans. In this study, we evaluate whether and how different types of masks affect perceptions of black and white male models. We find that non-black respondents perceive a black male model as more threatening and less trustworthy when he is wearing a bandana or a cloth mask than when he is not wearing his face covering—especially those respondents who score above average in racial resentment, a common measure of racial bias. When he is wearing a surgical mask, however, they do not perceive him as more threatening or less trustworthy. Further, it is not that non-black respondents find bandana and cloth masks problematic in general. In fact, the white model in our study is perceived more positively when he is wearing all types of face coverings. Although mandated mask wearing is an ostensibly race-neutral policy, our findings demonstrate the potential implications are not.

Formation and Characterization of CuPt-A type Ordered Structure in Cadmium Zinc Telluride Single Crystals

CrystEngComm ◽  
2022 ◽  
Author(s):  
Wanzhong Li ◽  
Jian Sun ◽  
Chong Deng
Keyword(s):  
Solar Cells ◽  
Single Crystals ◽  
Cadmium Zinc Telluride ◽  
Zinc Telluride ◽  
Radiation Detectors ◽  
Ordered Structure ◽  
Ordered Phases ◽  
Different Types ◽  
Cadmium Zinc

Cadmium Zinc Telluride (CdZnTe) single crystals have been widely ultilized in various photoelectron devices such as radiation detectors and solar cells. Different types of ordered phases have also been investigated...

scholarly journals Novel cloaking lamellar structures for a screw dislocation dipole, a circular Eshelby inclusion and a concentrated couple

2020 ◽  
Vol 476 (2241) ◽  
pp. 20200095
Author(s):  
Xu Wang ◽  
Peter Schiavone
Keyword(s):  
Conformal Mapping ◽  
Screw Dislocation ◽  
Lamellar Structure ◽  
Stress Fields ◽  
Uniform Stress ◽  
Dislocation Dipole ◽  
Lamellar Structures ◽  
Eshelby Inclusion ◽  
Mapping Techniques ◽  
Concentrated Couple

Using conformal mapping techniques, we design novel lamellar structures which cloak the influence of any one of a screw dislocation dipole, a circular Eshelby inclusion or a concentrated couple. The lamellar structure is composed of two half-planes bonded through a middle coating with a variable thickness within which is located either the dislocation dipole, the circular Eshelby inclusion or the concentrated couple. The Eshelby inclusion undergoes either uniform anti-plane eigenstrains or uniform in-plane volumetric eigenstrains. As a result, the influence of any one of the dislocation dipole, the circular Eshelby inclusion or the concentrated couple is cloaked in that their presence will not disturb the prescribed uniform stress fields in both surrounding half-planes.

Effect of Color Coding on Visually and Verbally Oriented Tests with Students of Different Field Dependence Levels

1992 ◽  
Vol 20 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Francis M. Dwyer ◽  
David M. Moore
Keyword(s):  
Field Dependence ◽  
Information Acquisition ◽  
Color Coding ◽  
Treatment Groups ◽  
Black And White ◽  
Field Dependent ◽  
Different Types ◽  
Respective Treatment ◽  
The Impact ◽  
Instructional Variable

To assess the impact of instructional color coding on visually and verbally oriented tests and on field-dependent-independent subjects, undergraduate college students (119) were randomly assigned to two treatment groups (color—black and white). These subjects received their respective treatment and received four dependent measures measuring four different types of educational objectives. Results indicated that the subject's level of field dependence is an important instructional variable and that color coding is an effective variable for maximizing information acquisition levels for field dependent over oriented subjects.

Lumineszenzuntersuchungen zum Problem der Energieübertragung in organischen Molekülkristallen

1970 ◽  
Vol 25 (6) ◽  
pp. 955-966 ◽  
Author(s):  
F. Belitz
Keyword(s):  
Energy Transfer ◽  
Single Crystals ◽  
Fluorescence Spectra ◽  
Dipole Interaction ◽  
Main Process ◽  
Transfer Processes ◽  
Decay Times ◽  
Different Types ◽  
The Mean ◽  
Host Lattices

Abstract From fluorescence spectra and decay times of single crystals of 2.3-dimethylnaphthalene, phenanthrene and p-terphenyl doped with one or two different types of fluorescence molecules (anthracene and, or tetracene) informations about the energy transfer processes are obtained. For doping concentrations smaller than 4·10-4 Mol/Mol the transfer by excitons is the main process. The dipole-dipole interaction over distances more than 80 Å (14 mean molecular distances) can be excluded. The mean travelling distance of the excitons in the three host lattices was found to be 250 - 300 mean molecular distances.

Sign in / Sign up

Export Citation Format

Share Document