The Concentration of Latex by Centrifugal Machines

1941 ◽  
Vol 14 (1) ◽  
pp. 160-175
Author(s):  
J. H. Piddlesden
Keyword(s):  
Research Work ◽  
Raw Material ◽  
New Materials ◽  
Rubber Content ◽  
Rubber Latex ◽  
Commercial Development ◽  
Shipping Cost ◽  
The Subject

Abstract Rubber latex has become a very important raw material and finds many applications, ranging from the proofing of fabrics and impregnation of paper to the manufacture of elastic threads, can-sealing compounds, adhesives, and upholstery. A large amount of research work has been carried out in the East with a view to supplying preserved latex suitable for these processes. The latex as it leaves the tree has an average dry rubber content of about 33 to 35 per cent, and is so unstable that it will coagulate within a few hours unless a preservative is added. Ammonia has been found to be a suitable preservative and, in spite of the continued search for new materials, it remains in general use. The problem of concentrating the latex to avoid the shipment of surplus water arose early. Three methods for carrying out this operation were developed, namely, centrifugal concentration, creaming by the addition of gums and mucilages, and evaporation. A fourth method, utilizing the phenomena of electrodialysis, has recently been the subject of commercial development. The advent of concentrated latex widened the field of latex applications, since the concentrated products found uses for which preserved field latex was not suitable. For many processes the properties and applications of the latex or concentrate are now perhaps more important that the question of shipping cost. Various types of product, described briefly below, are obtained from the different processes of concentration.

The State of Polydispersion of Hevea Latex. I

1946 ◽  
Vol 19 (1) ◽  
pp. 176-186
Author(s):  
J. H. E. Hessels
Keyword(s):  
Protein Content ◽  
Hevea Brasiliensis ◽  
The State ◽  
Rubber Content ◽  
Rubber Latex ◽  
Latex Particles ◽  
Rubber Particles ◽  
The Subject ◽  
Points Of View ◽  
Good Agreement

Abstract The rubber particles in the latex of Hevea brasiliensis are present in the form of a polydispersion, and their diameters lie within the range of 0.1 to 3 microns. The rubber hydrocarbon itself is composed of a mixture of macromolecules of different degrees of polymerization. Rubber latex is, therefore, a system which is at the same time both polydispersed and polymolecular. It is well known that the degree of dispersion of a substance governs to a great extent certain properties of the substance. Moreover, astonishing as it may seem, in the great number of investigations which have been made of the composition and properties of latex and crude rubber, almost no attention has been paid to the part which may be played by the dimensions of the latex particles. However, in an investigation concerned with the centrifugation of latex, Loomis and Stump have called attention to this possibility, and in a study of latex obtained by fractionation, and in which the majority of the latex particles were of large dimensions, McGavack came to the conclusion that the protein content is proportional to the surface area of the globules. This limited knowledge of the subject seemed to warrant a more thorough study of the problem, which is of fundamental importance both from the theoretical and practical points of view. The investigation as a whole divided itself into three essential parts: (1) separation of latex into fractions containing particles of different sizes, and measurement of the state of dispersion in these fractions, (2) a study of the relation of these fractions to the composition of the rubber, i.e., the relation between the content of nonrubber components and the size of the latex particles, and (3) a study of the changes in the properties of the rubber hydrocarbon with change in the size of the latex particles. The latex used in this investigation was ordinary latex, containing 38–40 per cent dry-rubber content and preserved with ammonia. For the most important points, a concentrated latex (creamed latex containing 60 per cent dry-rubber content) was also tested. These two latices were about two years old when the investigation was started, and they gave results which were in good agreement with each other. In the present paper, only the data obtained with the first of the two latices are presented.

“Channeling” the powers of God’s Word

2010 ◽  
Vol 4 (2) ◽  
pp. 135-156 ◽  
Author(s):  
Dorothea E. Schulz
Keyword(s):  
The Other ◽  
Border Zone ◽  
Focus Attention ◽  
Spiritual Power ◽  
New Materials ◽  
God's Word ◽  
Audio Recordings ◽  
Heated Debate ◽  
The Subject ◽  
The One

Starting with the controversial esoteric employment of audio recordings by followers of the charismatic Muslim preacher Sharif Haidara in Mali, the article explores the dynamics emerging at the interface of different technologies and techniques employed by those engaging the realm of the Divine. I focus attention on the “border zone” between, on the one hand, techniques for appropriating scriptures based on long-standing religious conventions, and, on the other, audio recording technologies, whose adoption not yet established authoritative and standardized forms of practice, thereby generating insecurities and becoming the subject of heated debate. I argue that “recyclage” aptly describes the dynamics of this “border zone” because it captures the ways conventional techniques of accessing the Divine are reassessed and reemployed, by integrating new materials and rituals. Historically, appropriations of the Qur’an for esoteric purposes have been widespread in Muslim West Africa. These esoteric appropriations are at the basis of the considerable continuities, overlaps and crossovers, between scripture-related esoteric practices on one side, and the treatment by Sharif Haidara’s followers of audio taped sermons as vessels of his spiritual power, on the other.

scholarly journals Experimental tests of PVD AlCrN-coated planer knives on planing Scots pine (Pinus sylvestris L.) under industrial conditions

2021 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Wojciech Kapłonek ◽  
Marzena Sutowska ◽  
Paweł Sutowski ◽  
Piotr Myśliński ◽  
...  
Keyword(s):  
Research Work ◽  
Experimental Tests ◽  
Technical Condition ◽  
Cutting Edge ◽  
Raw Material ◽  
Edge Condition ◽  
Wear Area ◽  
Pine Wood ◽  
Wood Processing ◽  
Machining Operations

AbstractRaw pine wood processing and especially its mechanical processing constitute a significant share among technological operations leading to obtaining a finished product. Stable implementation of machining operations, ensuring long-term repeatable processing results depends on many factors, such as quality and invariability of raw material, technical condition of technological equipment, adopted parameters of work, qualifications and experience of operators, as well as preparation and properties of the machining tools used. It seems that the greatest potential in the search for opportunities to increase the efficiency of machining operations has the modification of machining tools used in it. This paper presents the results of research work aimed at determining how the life of cutting tools used in planing operations of wet pine wood is affected by the application of chromium aluminum nitride (AlCrN) coating to planar industrial planing knives in the process of physical vapour deposition. For this purpose operational tests were carried out under production conditions in a medium-sized wood processing company. The study compares the effective working time, rounding radius, the profile along the knife (size of worn edge displacement, wear area of the cutting edge), selected texture parameters of the planar industrial planing knife rake face and visual analyses of cutting edge condition of AlCrN-coated planar knives and unmodified ones. The obtained experimental results showed the possibility of increasing the life of AlCrN-coated knives up to 154% compared to the results obtained with uncoated ones. The proposed modification of the operational features of the knives does not involve any changes in the technological process of planing, does not require any interference with the machining station nor its parameters, therefore enabling rapid and easy implementation into industrial practice.

The Smugglers' Trade: A Neglected Aspect of English Commercial Development

1952 ◽  
Vol 2 ◽  
pp. 131-157 ◽  
Author(s):  
G. D. Ramsay
Keyword(s):  
Eighteenth Century ◽  
Foreign Trade ◽  
Free Trade ◽  
Technical Skill ◽  
The Other ◽  
Raw Material ◽  
Commercial Development ◽  
Illicit Trade ◽  
Modern Times ◽  
Victorian Age

Some share—fluctuating and uncertain, but assuredly significant—of English foreign trade in modern times is to be credited to smugglers, who were ever busy in evading customs regulations and prohibitions. Mere administrative watchfulness and thoroughness could never do more than damp their activities; it was only the triumph of free trade in the early Victorian age that deprived them of their livelihood, and until then they were able to match by increase of cunning and of organization the ever more elaborate network of the customs system—its spies, its coastguards and its cutters as well as its routine officials at the ports. The smuggler flourished right down to the end of the period of protection, despite sporadic seizures by the revenue officers. In the first half of the nineteenth century, French wines, brandies and luxury textiles were being punctually shipped across the Channel in the teeth of prohibitions. In the other direction, we know, for instance, of the existence in the same period of so remarkable á phenomenon as the muslin manufacture of Tarare, near Lyons, which relied for its raw material upon the assured supply of English yarn owled abroad. But it was probably the eighteenth century, when customs regulations were at their most burdensome and complicated, that marked the classic epoch of illicit trade, the period in which the technical skill of both breakers and defenders of the law might earn the highest rewards.

Possible Causes in Breaking of Dental Implants Research

2017 ◽  
Vol 907 ◽  
pp. 104-118
Author(s):  
Maria Stoicănescu ◽  
Eliza Buzamet ◽  
Dragos Vladimir Budei ◽  
Valentin Craciun ◽  
Roxana Budei ◽  
...  
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Scientific Literature ◽  
Surface Characteristics ◽  
Raw Material ◽  
New Materials ◽  
Materials Used ◽  
Type Of Failure ◽  
First Time ◽  
Consequent Increase

Dental implants are becoming increasingly used in current dental practice. This increased demand has motivated manufacturers to develop varieties of product through design, but also looking for new materials used to improve surface characteristics in order to obtain a better osseointegration. But the increase in the use of implants goes to a consequent increase in the number of failures. These failures are caused either by treatment complications (peri-implantitis), by fatigue breakage under mechanical over-stress, by defective raw material, or due to errors during the insertion procedures. Although they are rare, these complications are serious in dentistry. Before to market a dental implant to clinical practitioners, the product is validated among other determinations in number of biocompatibility research. Raw material issues, details about its structure and properties are less published by the scientific literature, but all this are subject of a carefully analysis of the producers. Breaking of dental implants during surgical procedures, during the prosthetic procedures or during use (chewing, bruxism, accidents, etc.), is the second most common cause of loss of an implant after consecutive peri-implantitis rejection. Although the frequency of this type of failure for a dental implant is much smaller than those caused by the peri-implantitis, a detailed study of broken implants can explain possible causes. The use of scanning electron microscopy (SEM) in the study of the cleave areas explain the production mechanism of cleavages, starting from micro-fissures in the alloy used for the production of dental implants. These micro-fissures in weak areas of the implant (anti-rotational corners of the polygons, etc.) could generate a serious risk of cleavage first time when a higher force is applied.

Material Properties and Design Aspects of Folding Bicycle Frame

2011 ◽  
Vol 264-265 ◽  
pp. 777-782 ◽  
Author(s):  
M.A. Maleque ◽  
M.S. Hossain ◽  
S. Dyuti
Keyword(s):  
Material Properties ◽  
Raw Material ◽  
New Materials ◽  
Materials Properties ◽  
Advantages And Disadvantages ◽  
Bicycle Frame ◽  
Successful Design ◽  
Future Direction ◽  
The Relationship ◽  
Comprehensive Study

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.

Agglomeration Technologies of Processing Powder Wastes

2015 ◽  
Vol 244 ◽  
pp. 121-129
Author(s):  
Marian Peciar ◽  
Roman Fekete ◽  
Peter Peciar
Keyword(s):  
Research Work ◽  
Operating Conditions ◽  
Airborne Particles ◽  
Raw Material ◽  
Production Cycle ◽  
Shear Forces ◽  
Material Resources ◽  
New Type ◽  
Two Phases ◽  
High Technologies

This article deals with the presentation of modern applications for processing powdered, primarily hazardous, waste to an agglomeration form appropriate for subsequent processing by classical methods, for example in the construction, automotive and consumer goods industries. The aim of the research work was to set appropriate operating conditions in order to appreciate currently non-processable wastes resulting from the intensive production of often extremely expensive materials. Technologies which enable returning powder waste back into the primary production cycle were developed and experimentally tested, thus saving raw material resources. When necessary for the fixing of fine airborne particles with a problematic compacting curve (hard to compress, repulsive due to the surface charge) extrusion processes using a patented technology enabling controlled modification of shear forces in the extrusion zone were successfully applied. A new type of axial extruder allows the elimination of the liquid phase and as a result prevents the clogging of the extrusion chamber. In the case of need for granulation of sensitive materials (for example pharmaceuticals not allowing the addition of any kind of agglomerating fluid or reacting strongly in the contact of the two phases), a process of compaction between rolls with different profiled surface was successfully applied. The developed high technologies and the resulting products thus represent a major contribution to environmental protection in the context of not only the work but also the communal environment.

Studies Concerning the Corrosion Behaviour of the Cast Stainless Steel Used for Chemical Industry

2013 ◽  
Vol 371 ◽  
pp. 338-342
Author(s):  
Gheorghe Simionescu ◽  
Mirela Gheorghian
Keyword(s):  
Chemical Industry ◽  
Room Temperature ◽  
Corrosion Behaviour ◽  
Research Work ◽  
Experimental Tests ◽  
Hot Environment ◽  
Chemical Agents ◽  
The Subject ◽  
Materials Used ◽  
Cast Stainless Steel

The current work deals with experimental tests concerning the behaviour of different materials used in chemical industry when are exposed to diverse corrosions environments. During the research work four different metals have been tested, namely T15NiCr180, T15MoNiCr180, W4027 and W4059. The presented work is trying to classify the tested materials function to different chemical environment, different concentration of the environment, different temperature of the environment, and different expose time. Some of the substances which were considered as corrosion environment are: HNO3, H3PO4, NaCl, NH4Cl, C2H5OH, Petrol, NH4NO3, KNO3, K2CO3, Na2CO3, KMnO4, KOH and Ca (OH)2. The concentration of the corrosion solutions varies between 1% and 96%. Tests have been done at room temperature and hot environment of 100°C. Time is playing an important role on evolution of the corrosion. For this reason the samples have been analyzed after 48, 336, 720 and 2160 hours of exposes to chemical agents. To understand the comportment of the subject metals when are used in industry, samples have been tested for longer period of time, respectively 1, 3, 6 and 12 months. After each selected period of time the metallic samples were analyzed and measured to quantify the effect of the environment on the corrosion speed.

scholarly journals The Kodak research laboratories

1948 ◽  
Vol 135 (879) ◽  
pp. 133-147
Keyword(s):  
New York ◽  
Research Laboratory ◽  
New Materials ◽  
General Electric Company ◽  
Electric Company ◽  
Light Filters ◽  
University College London ◽  
The Subject ◽  
Work Done ◽  
Dark Room

In 1880 George Eastman commenced the manufacture and sale of gelatin photographic dry plates in Rochester, New York. From that undertaking, the Eastman Kodak Company, incorporated as an American company in 1902, has developed. In 1912 Mr Eastman decided to organize a laboratory, independent of the factory laboratories, which should carry out work on both the science and practice of photography. He was influenced by his observation of the success of industrial research under Dr Whitney’s direction at the research laboratory of the General Electric Company in Schenectady, New York, U. S. A. and of the laboratories of the great German dye works. He had been particularly impressed by the work done by the Bayer Company at Elberfeld. In 1906 I had completed my thesis for the doctorate of science at University College, London, the subject being the theory of the photographic process, and had joined the old-established but very small firm of Wratten and Wainwright, Ltd., of Croydon as joint managing director. At Croydon both the conduct of research on photography and its application to the manufacture of photographic materials were continued actively, so that by 1912 many new materials had been introduced, especially panchromatic plates and the light filters and dark-room safe-lights required for their use; and the little firm was flourishing.

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