scholarly journals A Defect Study and Classification of Brown Diamonds with Non-Deformation-Related Color

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 914
Author(s):  
Thomas Hainschwang ◽  
Franck Notari ◽  
Gianna Pamies
Keyword(s):  
Low Temperature ◽  
Absorption Band ◽  
Nir Spectroscopy ◽  
Extreme Conditions ◽  
Surprising Result ◽  
New Classification ◽  
The Many ◽  
Nm Range ◽  
Brown Color

While the first part of this study took a detailed look at the properties, defects and classification of brown diamonds with deformation-related (DR) brown color and compared them to pink to purple to red diamonds, this second part covers diamonds with non-deformation-related (referred to as NDR in this study) brown color, including diamonds with treatment-induced brown color and synthetic brown diamonds. It was found that the natural NDR brown diamonds include CO2 and Pseudo CO2 diamonds as well as certain hydrogen-rich diamonds. Based on these, the new classification of NDR brown diamonds has been elaborated, resulting in 5 different classes. The detailed defect study performed has shown and confirmed the complexity of the CO2 and Pseudo CO2 diamonds; the probable link between structurally bound oxygen and some of the spectroscopic features such as the 480 nm absorption band is apparent in these diamonds. One of the most interesting findings was made through the low temperature NIR spectroscopy of some usually hydrogen-rich diamonds, which has defined a defect of great interest, the 1330 nm center; we suggest that this defect, together with the many lines in the 970 to 1000 nm range—referred to as the 990 nm series in this study—are responsible for the complex UV-Vis-NIR spectra seen of these diamonds. The results indicate that both features are nickel-nitrogen-related defects, the 1330 nm defect without involvement of hydrogen and the 990 nm series likely with hydrogen involved. Another surprising result was that during various treatment experiments performed we created dark orangish brown color in originally pale yellow “cape” diamonds by HPHT treatment at 2500 °C. It is suggested that the creation of this brown hue is related to the destruction or transformation of the N3 center at such extreme conditions.

The new classification of the smut fungi, exemplified by Australasian taxa

2001 ◽  
Vol 14 (3) ◽  
pp. 385 ◽  
Author(s):  
Kálmán Vánky
Keyword(s):  
Morphological Characters ◽  
Molecular Data ◽  
Smut Fungi ◽  
Surprising Result ◽  
New Classification ◽  
Close Relationship ◽  
Water Plants ◽  
Classificatory System ◽  
New System

The 150 years old classificatory system for smut fungi was recently replaced by a new one, based on ultrastructural and molecular studies and also on classical morphological characters. The c. 1450 known ‘classical’ smut fungi (those possessing ustilospores) are classified into two classes, eight orders, 18 families and 73 genera. The surprising result in this new system is that the Microbotryales, with 93 species in eight genera, are more closely related to the rust fungi than to the remaining group of smut fungi. This is supported by biochemical, ultrastructural and molecular data. In the new system, some groups of fungi are lacking ustilospores (Microstromatales, Exobasidiales). Through convergent evolution, similar, complex spore ball structures, composed of spores and empty sterile cells, evolved from different ancestors as adaptation to parasitism on water plants (Doassansiopsiaceae and Doassansiaceae). The presence (or absence) of spore balls does not always reflect a close relationship as was previously thought: in the Doassansiaceae, characterised so far mainly by spore balls, Doassinga has single spores. Examples of Australasian taxa and their place in the new classification, presented are Doassansiopsis, Doassingaand Pseudotracya of the ‘Doassansia’ group, Mundkurella, Heterotolyposporium, Websdanea, Restiosporium and within the Microbotryales Microbotryum (Microbotryaceae), Fulvisporium and Bauerago (Ustilentylomataceae).

scholarly journals A Defect Study and Classification of Brown Diamonds with Deformation-Related Color

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 903 ◽  
Author(s):  
Thomas Hainschwang ◽  
Franck Notari ◽  
Gianna Pamies
Keyword(s):  
Low Temperature ◽  
Annealing Temperature ◽  
Negative Charge ◽  
Large Range ◽  
Side Product ◽  
New Classification ◽  
Naturally Occurring ◽  
The One ◽  
Annealing Experiments

For this study, the properties of a large sample of various types of brown diamonds with a deformation-related (referred to as “DR” in this work) color were studied to properly characterize and classify such diamonds, and to compare them to pink to purple to red diamonds. The acquisition of low temperature NIR spectra for a large range of brown diamonds and photoexcitation studies combined with various treatment experiments have opened new windows into certain defect characteristics of brown diamonds, such as the amber centers and naturally occurring H1b and H1c centers. It was determined that the amber centers (referred to as “AC” in this work) exhibit rather variable behaviors to annealing and photoexcitation; the annealing temperature of these defects were determined to range from 1150 to >1850 °C and it was found that the 4063 cm−1 AC was the precursor defect of many other ACs. It is suggested that the amber centers in diamonds that contain at least some C centers are essentially identical to the ones seen in diamonds without C centers, but that they likely have a negative charge. The study of the naturally occurring H1b and H1c link them to the amber centers, specifically to the one at 4063 cm−1. Annealing experiments have shown that the H1b and H1c defects and the 4063 cm−1 AC were in line with each other. The obvious links between these defects points towards our suggestion that the H1b and H1c defects are standalone defects that consist of multiple vacancies and nitrogen and that they are—in the case of brown diamonds—a side product of the AC formation. A new classification of DR brown diamonds was elaborated that separates the diamonds in six different classes, depending on type and AC. This classification had been completed recently with the classification of brown diamonds with a non-deformation-related color (referred to as “NDR”), giving a total of 11 classes of brown diamonds.

scholarly journals Raman Spectrum of Rubidium Thiocyanate at 37 K and Room Temperature

1989 ◽  
Vol 42 (4) ◽  
pp. 389 ◽  
Author(s):  
MJ Joyce ◽  
F Ninio
Keyword(s):  
Raman Spectrum ◽  
Low Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Temperature Data ◽  
Phonon Modes ◽  
New Classification ◽  
External Mode ◽  
Recent Interpretation

The single crystal Raman spectrum of RbSCN from 0 to 2200 cm-l was studied between 37 K and room temperature. A new eak was observed in the B2g polarisation and is believed to be an external mode. The low temperature data indicate that previous interpretations of the external modes are in error. A new classification of these modes is given. Further, whereas the internal modes are in agreement with previous studies, some multi phonon modes are not. The assumed isomorphism between bSCN and KSCN suggests a correction to the most recent interpretation of the spectrum

New Classification of Gemstone Colours

1971 ◽  
Vol 12 (7) ◽  
pp. 262-266
Author(s):  
K. F. Chudoba
Keyword(s):  
New Classification

Reductionism and holism in the philosophy of medicine

2020 ◽  
pp. 66-74
Author(s):  
E. Zakablukovskiy
Keyword(s):  
Philosophy Of Medicine ◽  
Point Of View ◽  
Social Model ◽  
Macro Level ◽  
New Classification

The article highlights certain aspects of the discussion on the topic of reductionism vs. holism in the philosophy of medicine. Classic radical reductionism is defeated by the concept of emergence. The s.c. bio-medical point of view on a malady, despite its relevance and clear benefit, is not recognized as universal as its adherents may claim, and it yields to an integral psycho-bio-social model. The author introduces a new classification of holism (vitalistic, social and individualistic) and makes appropriate recommendations to clinicians. It is social holism at the macro level that has proven effective in combating the spread of COVID-19.

Effectiveness of Supervised Classification Models for Hate Speech on Twitter

2020 ◽  
Author(s):  
Kunal Srivastava ◽  
Ryan Tabrizi ◽  
Ayaan Rahim ◽  
Lauryn Nakamitsu
Keyword(s):  
Supervised Classification ◽  
Hate Speech ◽  
The Internet ◽  
Classification Models ◽  
Personal Attack ◽  
Political Beliefs ◽  
The Many ◽  
Primary Medium ◽  
Offensive Speech

<div> <div> <div> <p>Abstract </p> <p>The ceaseless connectivity imposed by the internet has made many vulnerable to offensive comments, be it their physical appearance, political beliefs, or religion. Some define hate speech as any kind of personal attack on one’s identity or beliefs. Of the many sites that grant the ability to spread such offensive speech, Twitter has arguably become the primary medium for individuals and groups to spread these hurtful comments. Such comments typically fail to be detected by Twitter’s anti-hate system and can linger online for hours before finally being taken down. Through sentiment analysis, this algorithm is able to distinguish hate speech effectively through the classification of sentiment. </p> </div> </div> </div>

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