Some thoughts on the future of natural science, with illustrations from the growth of X-ray diffraction work in the United States

1954 ◽  
Vol 5 (6) ◽  
pp. 199-204 ◽  
Author(s):  
Ralph W G Wyckoff
Author(s):  
HERMAN SURYADI ◽  
SUTRIYO ◽  
Mira Junnisa ◽  
YULIANITA PRATIWI INDAH LESTARI

Objective: This study aimed to find psychochemical properties of microcrystalline cellulose (MCC) obtained from α-cellulose kapok pericarpium. Methods: The cellulase activity was screened by clear zone and sugar reduction method. The enzym from selected mold was purified by diethylaminoethyl (DEAE) chromatography. α-cellulose of kapok pericarpium was hydrolyzed using the purified cellulase enzymes. Microcrystalline cellulose (MCC) identified by Fourier transform infrared (FTIR) spectrometry, and qualitative analysis test. The samples were characterized for pH test, x-ray diffraction (XRD), and particle size analyzer (PSA). Results: The optimum cellulase activity was shown by Penicillium vermiculatum. It’s clear zone diameter around 3 cm and the cellulase activity was 67.73±0.25 mU/ml. The strongest cellulase activity was detected from 1st fraction (P1) out of 6 column fractions with optimum activity at 1.177±2 mU/ml. The optimal conditions for microcrystalline cellulose (MCC) preparation were at 50 ˚C, for 2 ours, using 20 ml of acetate buffer pH 5 and 2 ml of cellulase enzyme. Microcrystalline cellulose (MCC) obtained at 78% w/w and its FTIR spectrum and x-ray diffractogram similar to reference while the pH of MCC was fulfilled requirements of The United States Pharmacopoeia 2007. Conclusion: The use of purified enzyme of cellulase has succeded in microcrystalline cellulose (MCC) preparation andmicrocrystalline cellulose (MCC) obtained was 78% w/w, with similar characteristics to reference (Avicel PH 101) and the pH of MCC was fulfilled requirements of The United States Pharmacopoeia 2007.


1992 ◽  
Vol 7 (2) ◽  
pp. 71-76 ◽  
Author(s):  
N.J. Elton ◽  
P.D. Salt ◽  
J.M. Adams

AbstractLegislation in the United States and Canada requires labelling of products containing ≥ 0.1 wt.% crystalline silica. Kaolin clays are used in a variety of industries and usually contain low levels of total (i.e., respirable plus non-respirable) quartz, even after beneficiation. X-ray diffraction procedures have been developed here which are suitable for the quantification of total quartz in commercial kaolins with accuracy sufficient to satisfy the legislation. Separation and analysis of the respirable fraction is not addressed in this paper; however, the procedures described would be applicable to such samples if sufficient were available. Use of the 50.1° 2θrather than the 26.6° 26 (CuKα) quartz peak avoids most of the potential problems of overlap with reflections from other accessory minerals. It is shown that profile fitting techniques and optimised experimental procedures allow the determination of quartz in bulk samples to ± 0.03 wt.% (95% confidence) at the 0.1 wt.% level, and ± 0.1 wt.% at the 1.0 wt.% level, with tolerable data collection times.


2017 ◽  
Vol 81 (5) ◽  
pp. 1125-1128 ◽  
Author(s):  
Anthony R. Kampf ◽  
Stuart J. Mills ◽  
Mike S. Rumsey

AbstractGirdite, a mineral described byWilliams in 1979 from the Grand Central mine, Tombstone, Cochise County, Arizona, USA, has been re-examined by powder X-ray diffraction, single-crystal X-ray diffraction and electron microprobe. Type material from The Natural History Museum, London and the United States National Museum of Natural History (Smithsonian Institution) was examined. The original description of girdite is shown to have been based upon data obtained from at least two and possibly three different phases, one corresponding to ottoite and another probably corresponding to oboyerite, although the latter itself appears to be a mixture. The discreditation of girdite as a valid mineral species has been approved by the IMA-CNMNC, Proposal 16-G.


2014 ◽  
Vol 7 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Elisabeth Scheibelhofer

This paper focuses on gendered mobilities of highly skilled researchers working abroad. It is based on an empirical qualitative study that explored the mobility aspirations of Austrian scientists who were working in the United States at the time they were interviewed. Supported by a case study, the paper demonstrates how a qualitative research strategy including graphic drawings sketched by the interviewed persons can help us gain a better understanding of the gendered importance of social relations for the future mobility aspirations of scientists working abroad.


2003 ◽  
Vol 20 (3-4) ◽  
pp. 46-82
Author(s):  
Fathi Malkawi

This paper addresses some of the Muslim community’s concerns regarding its children’s education and reflects upon how education has shaped the position of other communities in American history. It argues that the future of Muslim education will be influenced directly by the present realities and future trends within American education in general, and, more importantly, by the well-calculated and informed short-term and long-term decisions and future plans taken by the Muslim community. The paper identifies some areas in which a wellestablished knowledge base is critical to making decisions, and calls for serious research to be undertaken to furnish this base.


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