Development of a Raman spectrometer for the Characterization of Gaseous Hydrocarbons at High Temperatures

AbstractIntroduction:The tropical plant amylases involved in the fruit ripening stage is outstanding for their high activities in converting starch to sugars within a short period at high temperatures over 40°C.Methods:The α amylase iso-enzymes from Ok-Rong mango (Results:The enzyme was purified 105-fold with a final specific activity of 59.27 U mgConclusion:Two α amylase iso-enzymes were classified as members of the low-pI group of amylases with identical structure, properties and functions. They are mesophilic with high possibilities for application for many purposes.

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Non-Invasive Characterization of Single-, Double- and Triple-Viral Diseases of Wheat With a Hand-Held Raman Spectrometer

Frontiers in Plant Science ◽

10.3389/fpls.2020.01300 ◽

2020 ◽

Vol 11 ◽

Author(s):

Charles Farber ◽

Rebecca Bryan ◽

Li Paetzold ◽

Charles Rush ◽

Dmitry Kurouski

Keyword(s):

Viral Diseases ◽

Raman Spectrometer ◽

Non Invasive

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Characterization of Boron Nitride Coated Silicon Carbide Fibers and Composites

Microscopy and Microanalysis ◽

10.1017/s1431927600010552 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 733-734

Author(s):

Mani Gopal

Keyword(s):

Silicon Carbide ◽

Boron Nitride ◽

High Temperatures ◽

Specimen Preparation ◽

Ion Milling ◽

Sic Fibers ◽

Silicon Carbide Fibers ◽

Pull Out ◽

Sic Composites

Silicon carbide (SiC) composites are receiving much attention for structural use at high temperatures. One class of composites are those reinforced with SiC fibers. The SiC fibers are coated with boron nitride (BN) which is weakly bonded to the fiber. During fracture, the coating deflects cracks causing pull-out of the fibers (Fig. 1). This process of fiber pull-out consumes energy and increases the toughness of the composite. Although much work has been done on characterizing these materials by SEM, not much has been done using TEM due to difficulties in specimen preparation. The purpose of this study is to characterize these fibers and composites using conventional and analytical TEM.In this study, TEM specimens were prepared by dimpling and ion milling. Careful control of the preparation was needed to ensure the integrity of the SiC-BN interface. Figure 2a is a TEM image of the fiber showing delamination at the SiC-BN interface.

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Experimental analysis of the spalling phenomenon in precast reinforced concrete columns exposed to high temperatures

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952018000400011 ◽

2018 ◽

Vol 11 (4) ◽

pp. 856-875 ◽

Cited By ~ 1

Author(s):

A. M. GIL ◽

B. FERNANDES ◽

F. L. BOLINA ◽

B. F. TUTIKIAN

Keyword(s):

High Temperatures ◽

Concrete Columns ◽

Concrete Cover ◽

Concrete Compressive Strength ◽

Concrete Mixtures ◽

Strength Tests ◽

Fire Curve ◽

Cover Thickness ◽

Real Scale

Abstract Among the processes that involve the degradation of concrete structures subject to the high temperatures of a fire there is the spalling phenomenon. Its mechanisms are related to the thermal stress of the materials dilatations and pore pressure the process of vaporization of water during heating. The factors that influences in its occurrence are related to concrete properties, structural member characteristics or the exposure conditions, and their parameters are not clearly known yet. This paper aimed to study the influence of three concrete mixtures, four coating thicknesses and two bars diameters of longitudinal reinforcement in the spalling phenomena exposed to ISO 834 fire curve. The characterization of concrete were performed either of the axial compression strength tests, water absorption by capillary and mercury intrusion porosimetry, besides the fire resistance tests in real-scale specimens. It was concluded that the diameter of the bar does not have influence, while the mixture and the concrete cover thickness does. More spalling was recorded for the columns with thicker concrete cover and concrete compressive strength at 61,9 MPa, and although higher strength concrete have less permeability, this characteristic can be balanced with the higher tensile strength of this type of concrete.

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Synthesis and Physical Properties of Skutterudite Superlattices

MRS Proceedings ◽

10.1557/proc-626-z2.3 ◽

2000 ◽

Vol 626 ◽

Author(s):

Joshua R. Williams ◽

David C. Johnson ◽

Michael Kaeser ◽

Terry Tritt ◽

George Nolas ◽

...

Keyword(s):

Thermal Conductivity ◽

Physical Properties ◽

High Temperatures ◽

Synthesis And Characterization ◽

Superlattice Structure

ABSTRACTPredicted and observed reductions in thermal conductivity of materials with superlattice structure have prompted interesting research into the possibility of using these materials as higher efficiency thermoelectrics. Synthesis of superlattice materials is challenging however, as the structure itself is generally not very stable at high temperatures as it is prone to interdiffusion. Presented here is the successful synthesis and characterization of a superlattice composed of two materials with the skutterudite structure, IrSb3 and CoSb3.

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On the Characterization of the Putative S20-Thx Operon of Thermus thermophilus

Biological Chemistry ◽

10.1515/bc.2001.126 ◽

2001 ◽

Vol 382 (7) ◽

pp. 1001-1006 ◽

Cited By ~ 5

Author(s):

Fotini Leontiadou ◽

Dimitra Triantafillidou ◽

Theodora Choli-Papadopoulou

Keyword(s):

High Temperatures ◽

Genomic Dna ◽

Ribosomal Proteins ◽

Positive Charge ◽

Thermus Thermophilus ◽

Promoter Sequence ◽

30S Subunit ◽

Feature Characteristic ◽

Putative Operon

Abstract A putative operon of the ribosomal proteins S20 and Thx has been determined in a 1.4 kb sequenced region of T. thermophilus genomic DNA. Both genes have a promoter sequence 29 nt upstream of ORF1, possess their own ShineDalgarno motifs (GGAG) and are separated by only 9 nucleotides, a feature characteristic of the compact Thermus thermophilus genome. This is a novel arrangement, since Thx is unique to the Thermus bacteria and in all other prokaryotes the S20 gene is monocistronic. Our results, in conjunction with the recent finding that Thx is located on the top of the head of the 30S subunit in a cavity between multiple RNA elements stabilizing them with its positive charge, corroborate the observation that thermophilic ribosomes require constituents with special features for their stabilization at high temperatures.

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