Rubber as it is Revealed by X-Rays

1929 ◽  
Vol 2 (2) ◽  
pp. 225-236
Author(s):  
George L. Clark
Keyword(s):  
Photographic Film ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Past ◽  
Logical Time ◽  
The Status ◽  
History Of ◽  
Clear Thinking ◽  
Pass Through

Abstract THE beginning of the year of 1929 seems to be a logical time for considering critically the status of knowledge concerning the fundamental structure of rubber. Of all the contributions by various methods to the problem, those which have come as a result of the application of X-ray diffraction methods may be considered the most unique and perhaps most important in the past few years. It was known previous to 1925 that when rubber is strongly stretched it becomes warm, its specific gravity increases and it becomes doubly refracting. The name of J. R. Katz has become renowned throughout the world as a result of the experiment which he performed of causing a fine beam of X-rays to pass through a specimen of stretched rubber behind which was placed a photographic film. This experiment was one of those fortunate accidents which appear frequently in the history of science, but on the other hand, it was the result of clear thinking, rational deduction, and a keen appreciation of the possibilities of application of X-rays to the examination of the ultimate structure of materials.

The Discovery of X-Rays: a Probable Case of Second Order Observation

2018 ◽  
Vol 19 (4) ◽  
pp. 403
Author(s):  
Marco Aurélio Clemente Gonçalves ◽  
Mariele Regina Pinheiro Gonçalves ◽  
Pablo Eduardo Ortiz
Keyword(s):  
History Of Science ◽  
Second Order ◽  
Point Of View ◽  
X Rays ◽  
Historical Reconstruction ◽  
X Ray ◽  
Probable Case ◽  
The Status ◽  
History Of

The discovery of x-rays, one of the most beautiful experiments ever carried out, generates numerous controversies and these, in turn, can trigger a series of counterproductive information regarding not only the History of Science but also the teaching  activity. The aim of this article is to resolve these controversies concerning what ocurred and highlight the important role of the German physicist Wilhelm Conrad Röntgen, highlighting not only his genius but, especially in this case in particular, his condition of second-order observer. It is not uncommon to find information in various media refering to this discovery under the claim that it was the result of a fortuitous event, and this denotes a profound lack of knowledge about the facts or a disrespect for the renowned discoverer. Such allegations about the event depreciate the extraordinary discovery that impacts humanity, from the deed  to the present. Thus, through a brief historical reconstruction, it was tried to present here what had happened judiciously. With this respect, the brilliant scientist is given the status of a second-rate observer, from the philosophical point of view. This condition resonates with the diachronic aspect of the History of Science, according to the perspective presented here, and it is also supported by the time taken by the discoverer from the beginning of his research until the end of it. Keywords: X-Ray. Second-Order Observer. History of Science. ResumoO descobrimento dos raios-x, um dos mais belos experimentos já realizados, gera inúmeras controvérsias e essas, por sua vez, podem desencadear uma série de informações contraproducentes no tangente não só a História da Ciência como também à atividade de ensino. O presente artigo tem como objetivo dirimir tais polêmicas com respeito ao ocorrido e destacar o importante papel do físico alemão Wilhelm Conrad Röntgen, destacando não só sua genialidade, mas sobretudo, neste caso em particular, a sua condição de observador de segunda ordem. Não é raro encontrar em diversos meios de comunicação informações com respeito a referida descoberta sob a alegação de que a mesma fora fruto de um caso fortuito e isso denota profundo desconhecimento sobre os fatos, ou então, desrespeito com o renomado descobridor. Tais alegações sobre o sucedido depreciam a descoberta extraordinária que impacta a humanidade, desde o feito até a atualidade. Assim, através de breve reconstrução histórica, buscou-se aqui apresentar o ocorrido criteriosamente. Com este respeito passa-se a atribuir ao brilhante cientista a condição de observador de segunda ordem, do ponto de vista filosófico. Tal condição encontra ressonância no aspecto diacrônico da História da Ciência, segundo a perspectiva aqui apresentada e está amparada, também, pelo tempo empreendido pelo descobridor desde o início de sua pesquisa até a finalização da mesma. Palavras-chave: Raios-x. Observador de Segunda Ordem. História da Ciência.

X-Ray Diffraction – The Magic Wand

2020 ◽  
Vol 42 (3) ◽  
pp. 317-317
Author(s):  
Iqra Zubair Awan Iqra Zubair Awan
Keyword(s):  
Materials Science ◽  
Review Paper ◽  
Medical Community ◽  
X Rays ◽  
X Ray Diffraction ◽  
Medical Sciences ◽  
X Ray ◽  
Magic Wand ◽  
History Of ◽  
Engineering Materials

This review paper covers one of the most important discoveries of the last century, viz. X-ray diffraction. It has made enormous contribution to chemistry, physics, engineering, materials science, crystallography and above all medical sciences. The review covers the history of X-rays detection and production, its uses/ applications. The scientific and medical community will forever be indebted to Rand#246;ntgen for this invaluable discovery and to those who perfected its application.

X-Ray Diffraction as a Probe for Elastic Strain: Micro- and Nanoscale Investigation of Thin Metal Films

2004 ◽  
Vol 840 ◽  
Author(s):  
R. Spolenak
Keyword(s):  
Local Strain ◽  
Metal Films ◽  
X Rays ◽  
X Ray Diffraction ◽  
Large Area ◽  
Strain Measurements ◽  
X Ray ◽  
The Past ◽  
Time Space ◽  
Peak Broadening

ABSTRACTIn the past years the concept of measuring strain by x-rays has changed significantly. The combination of 3rd generation synchrotron sources, advanced focusing techniques and large area detectors has made it possible to probe volumes smaller than a cubic micron. This devolopment has made it possible to probe microstrains directly without having to rely on highly sophisticated models to evaluate peak broadening effects. This paper will provide a review of the state of art of local strain measurements by x-rays, discuss their limitations, provide an outlook of where the field may be going within the next years and address the most important issues to be solved. Examples will be given for the current limits in terms of resolution in time, space, strain and intensity.

Analysis of the Thermo-Structural Behavior of Polyethylene Using Simultaneous DSC/XRD

1985 ◽  
Vol 29 ◽  
pp. 315-322 ◽  
Author(s):  
C. E. Crowder ◽  
S. Wood ◽  
B. G. Landes ◽  
R. A. Newman ◽  
J. A. Blazy ◽  
...  
Keyword(s):  
Thermal Conditions ◽  
Atmospheric Environment ◽  
Structural Behavior ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Past ◽  
Polymer Properties ◽  
History Of

Over the past 25 years, numerous studies of polymers utilizing both X-ray diffraction (XRD) and differential scanning calorimetry (DSC) have been reported in the literature. These studies have suffered because the two techniques must be performed on separate samples and under conditions that are often dissimilar. By combining the two techniques into one instrument, typical problems encountered with variations in sample preparation and thermal and atmospheric environment are eliminated. This is quite important in the study of polymers since one must match not only temperatures between the two techniques, but also heating rates as well. Matched thermal conditions are necessary because polymer properties such as crystallinity and crystallite size depend on both the temperature and thermal history of the sample under study.

Identification of Crystalline Materials: Classification and Use of X-Ray Diffraction Patterns

1986 ◽  
Vol 1 (1) ◽  
pp. 2-6 ◽  
Author(s):  
J. D. Hanawalt ◽  
H. W. Rinn
Keyword(s):  
Theoretical Basis ◽  
X Rays ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Chemical Company ◽  
The Past ◽  
Different Types ◽  
Diffraction Patterns ◽  
Or Applications

In the course of the past few years, X-ray and spectroscopic methods of analysis have found an increasing usefulness at the Dow Chemical Company. There are a large number of different types of problems on which information can be obtained by the variations of apparatus and technic which are possible in these two fields. It is not the purpose of this paper, however, to discuss these methods or applications in general, but to describe in some detail a scheme of classifying and using X-ray diffraction patterns which has been found very helpful in one particular application of X-rays — namely, that of identifying unknown substances by means of their Hull powder diffraction patterns.The inherent power of X-ray diffraction as a practical means of chemical analysis was pointed out a good many years ago. Having a different theoretical basis and depending upon an entirely different technic than other methods, it would be expected to supplement the information to be obtained from other methods and, at times, to be applicable where other methods are not suitable. It appears, however, that the use of this method has not increased at a rate commensurate with its unique and valuable features, and that it is used by relatively few academic and industrial laboratories.

A cell for X-ray diffraction in liquids under moderate hydrostatic pressure

1989 ◽  
Vol 22 (6) ◽  
pp. 572-577 ◽  
Author(s):  
M. Geeves ◽  
P. Knight
Keyword(s):  
Hydrostatic Pressure ◽  
High Performance ◽  
X Rays ◽  
X Ray Diffraction ◽  
Plastic Sheet ◽  
X Ray ◽  
Oil Pump ◽  
Sample Chamber ◽  
A Cell ◽  
Pass Through

A portable cell is described which allows X-ray diffraction data to be collected from suspensions or mounted specimens in liquid under hydrostatic pressure. Pressure is applied via either an oil pump or a high-performance liquid chromatography pump. The temperature of the cell is controlled by a thermostatted baseplate. X-rays pass through the stainless steel block via windows of Kapton V plastic sheet which will withstand a pressure difference of at least 15 MPa. Distortion of the plastic under pressure increases the liquid path of the X-rays. This distortion can be reduced by stretching over dome-shaped supports. Under these conditions 10 MPa causes a reduction of intensity of between 10 and 50%, depending on window geometry. Specimens can be mounted on a removeable frame, and the solution in the sample chamber can be changed without disassembling the cell. The apparatus has been used successfully to study the low-angle diffraction from muscle.

scholarly journals Radiation damage in protein crystals examined under various conditions by different methods

2009 ◽  
Vol 16 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Elspeth F. Garman ◽  
Colin Nave
Keyword(s):  
Radiation Damage ◽  
Electronic State ◽  
Room Temperature ◽  
Protein Crystal ◽  
Protein Crystals ◽  
X Rays ◽  
X Ray Diffraction ◽  
Radiation Physics ◽  
X Ray ◽  
The Past

Investigation of radiation damage in protein crystals has progressed in several directions over the past couple of years. There have been improvements in the basic procedures such as calibration of the incident X-ray intensity and calculation of the dose likely to be deposited in a crystal of known size and composition with this intensity. There has been increased emphasis on using additional techniques such as optical, Raman or X-ray spectroscopy to complement X-ray diffraction. Apparent discrepancies between the results of different techniques can be explained by the fact that they are sensitive to different length scales or to changes in the electronic state rather than to movement of atoms. Investigations have been carried out at room temperature as well as cryo-temperatures and, in both cases, with the introduction of potential scavenger molecules. These and other studies are leading to an overall description of the changes which can occur when a protein crystal is irradiated with X-rays at both cryo- and room temperatures. Results from crystallographic and spectroscopic radiation-damage experiments can be reconciled with other studies in the field of radiation physics and chemistry.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

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