CHARACTERIZATION OF THE SINTERED Nd15Fe77B8 ALLOY

2011 ◽  
Vol 25 (06) ◽  
pp. 877-884
Author(s):  
L. HADJADJ
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Optical Microscope ◽  
The Other ◽  
Average Value ◽  
Nd15fe77b8 Alloy

In this work the purpose is, in addition to the determination of microhardness, to get some information about the effect of heat treatment on the microstructure of the magnetic Nd 15 Fe 77 B 8 alloy. For this study we have used an optical microscope and an electronic microprobe. The results show that the structure of the Nd 2 Fe 14 B phase, which confers good mechanical and magnetic properties on the alloy, is well tetragonal, as mentioned in several works. The morphology, the concentration and the quantity of this phase depend on the temperature of annealing. The microhardness of the phase has an average value between those of the other involved phases.

scholarly journals Ethylene and Lipoxygenase In Relation to Afterripening of Dormant NC-13 Peanut Seeds1,2

1985 ◽  
Vol 12 (1) ◽  
pp. 45-49 ◽  
Author(s):  
D. L. Ketring ◽  
H. E. Pattee
Keyword(s):  
Heat Treatment ◽  
Cold Storage ◽  
Ethylene Production ◽  
Sharp Increase ◽  
Gradual Increase ◽  
The Other ◽  
Immature Seeds ◽  
Positive Correlations ◽  
Mature Seeds

Abstract Following harvest, peanuts are usually subjected to a period of storage. During storage biochemical changes are known to occur. The objectives of this study were to determine the changes and relationship in ethylene production, germination, and lipoxygenase (LG) activity during cold storage of dormant NC-13 peanut seeds. Two seed lots (SL) were used: one grown in Oklahoma (SL80) and the other grown in N. Carolina (SL81). SL80 and SL81 were stored at 2 to 5 C for 193 and 242 days, respectively. Samples were taken at about 28-day intervals for determination of germination, ethylene production, and LG activity. Seeds of two and three maturities were tested for SL80 and SL81, respectively. As afterripening of stored seeds proceeded, ethylene production gradually increased, with the maximum at 48 hours of germination. Germination showed a concomitant gradual increase. Lipoxygenase activity of both seedlots was less for mature than for immature seeds and showed a sharp increase during storage at 2 to 5 C, particularly for immature seeds. After heat-treatment to break dormancy of sublots from SL81, there was a progessive increase in ethylene production and germination, but most notably for mature seeds. In contrast to ethylene production and germination, after heat-treatment LG activity declined. Linear correlation coefficient (r) values between ethylene production and germination were highly significant for mature seeds from SL80 at 48 and 72 hours of germination, but only at 72 hours for immature seeds. For SL81 as for SL80, significant positive correlations were found between ethylene production and germination. However, correlations between LG activity and the other variables were not significant except for mature seeds from SL81. Significant positive correlations for both ethylene production and germination with LG activity also existed for these seeds. But after heat-treatment these correlations no longer occurred. The data indicate that the metabolic processes related to ethylene production and germination are occurring simultaneously with those of LG activity. The possibility that metabolites from LG activity serve as substrates for ethylene production can not be precluded.

Effect of Post Weld Heat Treatment on Al 5052-SS 316 Explosive Cladding with Copper Interlayer

2018 ◽  
Vol 910 ◽  
pp. 35-40
Author(s):  
Eswaran Elango ◽  
Somasundaram Saravanan ◽  
Krishnamorthy Raghukandan
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Intermetallic Compounds ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Post Weld Heat Treatment ◽  
Inclination Angles ◽  
Copper Interlayer ◽  
Weld Heat

This study focuses on effect of post weld heat treatment (PWHT) on interfacial and mechanical properties of Al 5052-SS 316 explosive clad with copper interlayer at varied loading ratios and inclination angles. The use of interlayer is proposed for the control of additional kinetic energy dissipation and to alleviate the formation of intermetallic compounds at the interface. The Al-Steel clads are subjected to PWHT at varied temperatures (300°C-450°C) for 30 minutes and the results are presented. The microstructural characterization of as-clad and PWHT samples is observed by an optical microscope and Scanning Electron Microscope (SEM). Maximum hardness is obtained at the interface of the as-clad and PWHT samples. Increase in PWHT temperature enhances the tensile strength of the composite, whereas, the tensile strength decreases at 300°C due to the diffusion of Al and Cu elements and the formation of detrimental intermetallic compounds.

Isolation and Characterization of a Chlorogenic Acid Esterase from Aspergillus niger

1980 ◽  
Vol 35 (3-4) ◽  
pp. 209-212 ◽  
Author(s):  
B. Schöbel ◽  
W. Pollmann
Keyword(s):  
Enzyme Activity ◽  
Chlorogenic Acid ◽  
Divalent Cations ◽  
Hydrolysis Product ◽  
The Other ◽  
Temperature Optimum ◽  
Pig Liver ◽  
Isolation And Characterization

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split chloro­genic acid. The isoelectric focusing reveals several isoenzymes of chlorogenase within a pI-range of 4.0-4.5.

Characterization of Phthalate Plasticizer from Bottled Beverages by GC-MS

2013 ◽  
Vol 401-403 ◽  
pp. 590-593 ◽  
Author(s):  
Qiu Ju Sun ◽  
Lin Li ◽  
Zhong Li Jiang ◽  
Shi Gang Xin ◽  
Shi Wei Wu ◽  
...  
Keyword(s):  
Correlation Coefficients ◽  
The Other ◽  
Calibration Curves ◽  
Phthalate Plasticizer ◽  
Testing Data

A GC/MS method was established for the determination of phthalates plasticizers in bottled beverages. The calibration curves are all linear in the range of 0.01 to 5μg/L with correlation coefficients greater than 0.997. The recoveries are in the range between 97.27% and 105.05% under two levels. The testing data of the samples showed that the five bottled beverages all contained DBP, DIBP and DEHP plasticizers, and DIBP content was obviously higher than the other two.

scholarly journals The crystal structure of the heusler alloys

1934 ◽  
Vol 144 (852) ◽  
pp. 340-359 ◽  
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Heusler Alloys ◽  
The Other ◽  
X Rays ◽  
Ferromagnetic Alloys ◽  
Suitable Heat Treatment ◽  
Copper Manganese ◽  
Ferro Magnetic

Beginning in the year 1898 Heusler discovered as a series of ferromagnetic alloys, the most important containing copper, manganese, and aluminium. They are characterized by remarkable magnetic properties, because although composed only of paramagnetic or diamagnetic elements, they become ferro-magnetic after suitable heat treatment. Various explanations of this property have been advanced, but it was usually considered to be due to the formation of a series of solid solutions of the type (CuMn) 3 Al, in which the proportions of copper and manganese may be varied within fairly wide limits. The Heusler alloys have been repeatedly investigated by means of X-rays. Young, using molybdenum radiation examined alloys of two different compositions. He found that one was face-centred cubic, while the other was a mixture of face-centred and body-centred cubic structures. The mixed alloy was the more magnetic.

scholarly journals Pengaruh Perlakuan Panas Karburisasi Austemper pada Baja Laterit Paduan Cr-Mo terhadap Sifat Mekanik dan Struktur Mikro

2020 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Satrio Herbirowo ◽  
Vinda Puspasari ◽  
M. Iqbal Primatama ◽  
Hendrik Hendrik ◽  
I Nyoman Gede Putrayasa Astawa ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Surface ◽  
Surface Characterization ◽  
Impact Test ◽  
Optical Microscope ◽  
Air Blowing ◽  
Sample Characterization ◽  
Cooling Media ◽  
Steel Heat

This research was aimed to do heat treatment of austemper carburization and investigate the effect of various cooling media on mechanical properties and microstructure of Cr-Mo alloy lateritic steel. Heat treatment was conducted to austenisation temperature at 950o C for 1 hour and austemper carburization at 400o C for 1 hour. Variation of cooling media included air blowing for 1 hour, water, and furnace cooling for 24 hours. Hardness and impact test were done using Hardness Rockwell and Charpy methods. Microstructure was observed using optical microscope. Fracture surface characterization was using SEM-EDX. The results showed the highest hardness of 65.48 HRC in sample that cooled by air blowing for 1 hour. The microstructure of this sample showed phases of ferrite, pearlite and martensite which causing higher hardness. The highest impact strength of 20 Joule took place in the furnace cooled sample. Characterization of the fracture surface using SEM-EDX showed dimple of ductile fractures.Penelitian ini bertujuan untuk melakukan proses perlakukan panas karburisasi austemper dan mempelajari pengaruh media pendinginan terhadap sifat mekanik dan struktur mikro baja laterit paduan Cr-Mo. Perlakuan panas yang dilakukan yaitu pemanasan sampel pada temperatur austenisasi (950o C) selama 1 jam dan proses karburisasi austemper dengan media serbuk arang halus pada temperatur 400o C selama 1 jam. Variasi pendinginan yang digunakan yaitu air blowing (semburan udara) selama 1 jam, air dan tungku selama 24 jam. Pengujian kekerasan dilakukan dengan metode Rockwell Hardness dan pengujian impak dilakukan dengan metode charpy. Karakterisasi struktur mikro dilakukan dengan proses metalografi dan mikroskop optik. Karakterisasi permukaan patahan pengujian impak dilakukan dengan SEM-EDX. Hasil penelitian ini menunjukkan nilai kekerasan tertinggi yaitu 65,48 HRC terjadi pada sampel dengan air blowing selama 1 jam. Struktur mikro sampel tersebut menunjukkan adanya fasa ferit, perlit dan martensit yang membuat sampel menjadi keras. Nilai kekuatan impak tertinggi sebesar 20 Joule terjadi pada sampel dengan pendinginan di dalam tungku selama 24 jam. Karakterisasi permukaan patahannya menggunakan SEM-EDX menunjukkan adanya dimple dari patah ulet.

A Rapid Quantitative Assay of Factor VIII (AHG) Without the Use of Haemophilia A Plasma

1960 ◽  
Vol 04 (03) ◽  
pp. 323-330 ◽  
Author(s):  
Ernst G. Jung
Keyword(s):  
Quantitative Determination ◽  
Factor Viii ◽  
Vitamin K ◽  
The Other ◽  
Haemophilia A ◽  
Clotting Factors ◽  
Normal Range ◽  
Average Value ◽  
Good Concordance

SummaryA new method for the quantitative determination of factor VIII (AHG) without using haemophilia A plasma as test substrate has been described. The comparison to Geiger et al. shows a good concordance. The normal range of factor VIII in adults is 50—150% (normal plasma taken as 100%) and the average value of healthy newborns is 78%. This is compared to the average values of the other clotting factors in newborns. Factor VIII is not affected by deficient vitamin K resorption.

Determination of Superoxide Free Radical Ion and Hydrogen Peroxide as Products of Photosynthetic Oxygen Reduction

1975 ◽  
Vol 30 (1-2) ◽  
pp. 53-57 ◽  
Author(s):  
Erich Elstner ◽  
Claus Stoffer ◽  
Adelheid Heupel
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
The Other ◽  
Keto Acids ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen

Abstract Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H2O2 is responsible for the oxidation of hydroxylamine. Decarboxylation of α-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of α-keto acids can be used, therefor, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H2O2 and O2·-. The addition of an oxygen reducing factor (ORF, solubilized by heat - treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H2O2 , while O2·- - formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H2O2 not only by dismutation of O2·-, but also by a separate mechanism involving ORF.

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