Two Methods of Protection against Oxygen and the Improvement Which Results from Their Combined Use. I. Observations on the Mechanism of Protection

1947 ◽  
Vol 20 (4) ◽  
pp. 949-961 ◽  
Author(s):  
Jean Le Bras
Keyword(s):  
Physical Properties ◽  
Single Case ◽  
Protective Action ◽  
Harmful Effect ◽  
Point Of View ◽  
Theoretical Conclusion ◽  
Free Oxygen ◽  
Practical Point ◽  
Combined Use ◽  
Rate Of Absorption

Abstract The observations which are recorded in the present paper represent an extension of the single case of litharge which has already been described. They show that, when small percentages of certain substances are added to rubber with a view to protecting the rubber from deterioration by oxygen, these substances are capable of directing the combination of oxygen with the rubber in different ways. This is shown by the fact that, as a result, a given percentage of combined oxygen does not lead to the same deterioration in physical properties. This difference in behavior can be explained logically on the basis of the antioxygenic theory by assuming that some agents act, not by retarding the rate of oxidation, but by deactivating the peroxides as soon as they are formed. By what term are these agents to be designated? First of all it should be recalled how an antioxygenic substance is defined. Every substance is an antioxygenic agent when it has the power, in small percentages, of retarding the rate of absorption of free oxygen by an autoxidizable substance. This definition obviously does not apply to a perfect deactivating agent, since the latter has no effect on the rate of absorption of oxygen, in spite of it too protecting rubber against deterioration by oxygen, and therefore being equally worthy, from the practical point of view, of being called an antioxygenic agent. However, this would only lead to confusion between the phenomenon itself and its effects. Furthermore, since commercial antioxygenic substances appear to show, to a greater or less degree, a combination of the two actions, one might consider designating them by some term which would embody both mechanisms. The word “antiaging agent” is not suitable, for it is too general and applies to cases where, in addition to oxygen, other influences such as light and repeated flexing play a part. There is, then, a problem in terminology to be settled, but this will have to be left unanswered provisionally until sufficient facts which have a more direct bearing on the case are available. Finally attention should be called to the useful effect which may be pictured as a possibility when the two types of protective agents which have been described act jointly. In other words, if the two mechanisms in question were to be superimposed, it would appear to be possible to improve considerably the resistance of rubber to deterioration by oxygen, since any oxygen which escapes the protective action of the true antioxygenic agent has its harmful effect reduced by the deactivating agent. To express it figuratively, it might be said that oxygen which has succeeded in overcoming the first obstacle opposing its action finds itself confronted with a new defense which puts the oxygen partially out of action. As shown by experiments carried out on this subject, which are described in the following paper of this series, this theoretical conclusion is actually borne out by the results of the experiments.

Vulcanization of Synthetic Rubbers

1951 ◽  
Vol 24 (3) ◽  
pp. 569-573 ◽  
Author(s):  
A. P. Pisarenko ◽  
P. A. Rebinder
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Plastic Flow ◽  
Point Of View ◽  
Degree Of Saturation ◽  
Spatial Structures ◽  
Practical Point ◽  
Synthetic Rubber ◽  
Physico Chemical ◽  
Vulcanization Process

Abstract Although for a century since the discovery of the vulcanization of rubber by sulfur many investigators have worked in this field, the problem of vulcanization can still not be considered to be well understood, either from the theoretical or the practical point of view. The basis of the most widely accepted theory of vulcanization of rubber is the concept of bridges, according to which the vulcanizing agent, sulfur, unites the macromolecules of rubber into spatial chains by primary valences. The concept that such spatial structures are formed during the vulcanization process explains well the decrease in the degree of saturation of the rubber and the changes in its physical properties, e.g., decreases in solubility and plastic flow, and considerable increases in strength, modulus, and resilience. A number of experimentally established facts, however, can never be reconciled with the bridge theory of vulcanization, especially when the vulcanization of synthetic rubbers is investigated. As a consequence of this, a number of investigators in this country have pointed out the shortcomings of the bridge theory and the necessity of finding a better explanation of the physico-chemical and colloidal reactions which take place during the vulcanization of rubber. More recently Dogadkin and his associates have shown that even when an accelerator is added, which leads to an increase of the bridge sulfur content of the vulcanizate, the total amount remains insignificant, e.g., in the case of natural rubber it amounts to only 7–10 per cent and, in the case of synthetic rubber, to 2–6 per cent of the total bound sulfur.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

scholarly journals On the Design of Outdoor Leader-Follower UAV-Formation Controllers from a Practical Point of View

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Lucas Vago Santana ◽  
Alexandre Santos Brandao ◽  
Mario Sarcinelli-Filho
Keyword(s):  
Point Of View ◽  
Practical Point

Quantitative Analysis of Microstructure and Modeling of Sintering

2009 ◽  
Vol 624 ◽  
pp. 1-18 ◽  
Author(s):  
Jean Marc Chaix
Keyword(s):  
Image Analysis ◽  
Input Data ◽  
3D Imaging ◽  
Point Of View ◽  
Size Distributions ◽  
Practical Point ◽  
The Past ◽  
Modeling Techniques ◽  
Mean Size ◽  
Sintering Mechanisms

Microstructure is the key scale to understand and describe sintering mechanisms and their consequences at the macroscopic level. As modeling techniques are continuously developing, the need for input data and comparison with more and more accurate descriptions of the evolution is expected to create a growing demand for quantitative microstructure data. Image analysis is the classic way to get these data. This paper reviews the practical use and progresses of this old technique in the sintering literature during the past and recent years. The place of basic tools and more recent ones, such as 3D imaging, are discussed from a practical point of view accounting from sintering models needs: mean size and size distributions in pores and grains, homogeneity, sintering trajectories…

Technology and the management imagination

2005 ◽  
Vol 13 (3) ◽  
pp. 533-563 ◽  
Author(s):  
Fred Phillips
Keyword(s):  
Corporate Culture ◽  
Point Of View ◽  
Local Culture ◽  
Social Consensus ◽  
Practical Point ◽  
Research Questions ◽  
Crisis Managers

This paper explores the evolution of the techno-management imagination (TMI). This is the process by which, in times of crisis, managers think not just out of the box, but out of the very reality in which the box resides. Tacit social consensus, also known as corporate culture, can lead to a shared, implicit, and incorrect view that certain actions are impossible. TMI transcends local culture, accessing technological solutions that are unknown and/or unimagined. Members of the organization tend to call such solutions “magic”. The paper looks at social, perceptual, and managerial aspects of magic from a practical point of view that is grounded in research. It examines the risks of TMI, and concludes with suggested perspectives and research questions for management scientists and cognitive scientists.

Towards a New Model of Conversion Careers: the Impact of Personality and Contingency Factors

Exchange ◽  
2005 ◽  
Vol 34 (2) ◽  
pp. 149-166 ◽  
Author(s):  
Henri Gooren
Keyword(s):  
Religious Conversion ◽  
Religious Affiliation ◽  
Point Of View ◽  
Small Scale ◽  
Central Question ◽  
Roman Catholicism ◽  
Guatemala City ◽  
Practical Point ◽  
The Poor ◽  
The Impact

AbstractThe central question of this article — why people may change their religious affiliation or become disaffiliated — is relevant from both an academic and a practical point of view. The article makes first an inventory of existing literature on religious conversion. Next I sketch the contours of the new conversion careers approach I am currently working on. I make some comparisons with a region that is not usually mentioned in the literature on conversion: Latin America. These comparisons are based on my earlier fieldwork on Roman Catholicism, Pentecostalism, and Mormonism in Costa Rica and Guatemala (H. Gooren, Rich among the Poor: Church, Firm, and Household among Small-scale Entrepreneurs in Guatemala City, Amsterdam: Thela Thesis 1999).

DURATION OF ACARICIDAL ACTION OF THE DRUG «KENEM» AND ECONOMIC JUSTIFICATION FOR THE PROTECTION OF CATTLE FROM IXODIC MITES

Habarshy ◽  
2021 ◽  
pp. 50-60
Author(s):  
A.B. Myrzhiyeva ◽  
M.Zh Suleimenov ◽  
Uslu Ugur ◽  
A.S. Ibazhanova ◽  
L.O Zhanteliyeva L.O
Keyword(s):  
Economic Feasibility ◽  
Point Of View ◽  
Scientific Article ◽  
Special Equipment ◽  
Practical Point ◽  
Acaricidal Efficacy ◽  
Economic Justification ◽  
Long Duration ◽  
Similar Drug ◽  
The Cost

The scientific article presents the duration of acaricidal effect of «Kenem» drug, and its economic feasibility for protecting cattle against ixodic ticks. As a result of the study, the acaricidal efficacy and the duration of the residual acaricidal effect of drugs are important components in the planning of anti-tick measures. From a practical point of view, the economic feasibility of treating cattle against ixodic ticks in the presented conditions of acaricides in the southern regions is considered important. Despite the fact that the cost of the drug per 100 head exceeds the cost of a similar drug by 1 788.15 tenge, the frequency of its use is less, and additional installations are not required. This is due to the long duration of residual acaricidal effect of Kenem, which is 30 days, which allows to reduce the number of therapeutic measures.When calculating the economic feasibility for the use of acaricides to protect cattle against ixodic ticks, the most convenient way to prevent the sucking of ixodic ticks to animals is the local application of Kenem, which does not require special equipment and special skills of technical staff. Drug duration is 30 days, therefore the cost of its use for the entire season of active ticks per 1 animal is 44% cheaper, compared to veteran, i.e. 1,421.4 tenge.

New sustainable mortars for stone restoration in the context of climate change

2021 ◽  
Author(s):  
Jose Diaz-Basteris
Keyword(s):  
Physical Properties ◽  
Moisture Absorption ◽  
Raw Materials ◽  
Point Of View ◽  
Salt Crystallization ◽  
Glass Waste ◽  
Vapour Permeability ◽  
James Bond ◽  
S Waves ◽  
Environmental Agents

<p>Restoration mortars are a designated group of products made to repair damaged masonry. They must be compatible with the former support of stones and bricks, and protect original materials from environmental agents; aesthetical and historic aspects must not be neglected. </p><p>To improve the ecological footprint of the restoration mortars while keeping their efficiency, we have tested several combinations of lime with aggregates and additives. Recycled and natural materials were used as additives such as pinecone resin, semi-milled cones of pine, milled glass waste, brick production residue.</p><p>For research purposes different physical properties have been measured in prepared mortars: porosity, density, capillarity absorption, moisture absorption, water vapour permeability. We have also tested the mechanical properties and the P and S waves velocities (from which dynamic Young's modulus and Poisson’s ratio were inferred). The durability of mortars has been estimated by salt crystallization and frost/thaw cycles.</p><p>The life cycle analysis (LCA) of such mortars allows us to understand the carbon footprint of each manufacturing process. Considering this we selected the raw materials, from an environmental and commercial point of view, to produce mortars fulfilling sustainability requirements. As a result, the developed mortars are compatible with aged stones, minimize environmental impact, and use minimum natural resources.</p><p> Twenty mortar formulations with three different types of limes (NHL5, NHL3.5, CL90) and two different aggregates (siliceous and calcareous) have been studied using the LCA. Currently, five new formulations are being selected to be tested on Euville limestone. Adhesive strength (James Bond test), and physical properties will be measured on these mortars. </p>

On the readability of leaders in boundary labeling

2018 ◽  
Vol 18 (1) ◽  
pp. 110-132
Author(s):  
Lukas Barth ◽  
Andreas Gemsa ◽  
Benjamin Niedermann ◽  
Martin Nöllenburg
Keyword(s):  
Detailed Analysis ◽  
Task Performance ◽  
User Study ◽  
Point Of View ◽  
Practical Point ◽  
Subjective Preference ◽  
Two Measures ◽  
Preference Ratings ◽  
Boundary Labeling

External labeling deals with annotating features in images with labels that are placed outside of the image and are connected by curves (so-called leaders) to the corresponding features. While external labeling has been extensively investigated from a perspective of automatization, the research on its readability has been neglected. In this article, we present the first formal user study on the readability of leader types in boundary labeling, a special variant of external labeling that considers rectangular image contours. We consider the four most studied leader types (straight, L-shaped, diagonal, and S-shaped) with respect to their performance, that is, whether and how fast a viewer can assign a feature to its label and vice versa. We give a detailed analysis of the results regarding the readability of the four models and discuss their aesthetic qualities based on the users’ preference judgments and interviews. As a consequence of our experiment, we can generally recommend L-shaped leaders as the best compromise between measured task performance and subjective preference ratings, while straight and diagonal leaders received mixed ratings in the two measures. S-shaped leaders are generally not recommended from a practical point of view.

scholarly journals The theory of photographic processes, part II: On the chemical dynamics of development, including the microscopy of the image

1905 ◽  
Vol 76 (509) ◽  
pp. 217-234 ◽  
Keyword(s):  
Heterogeneous Systems ◽  
Point Of View ◽  
The Other ◽  
Chemical Dynamics ◽  
Practical Point ◽  
Previous Communication ◽  
The One

The investigation of development described in a previous communication was extended by the application of microscopic methods. The fact that both the silver haloid and the resulting silver are distributed through the film in the form of particles of minute but measurable size, allows us in this way to detect finer qualitative differences in, and to draw independent deductions on the processes of exposure and development. The size of the grain is important, both from the practical point of view and from the theoretical: in the one case as bearing on spectroscopical and astronomical photography, in the other on account of the great importance of the degree of surface-extension for heterogeneous systems. The method has been used previously by Abney, Abegg, Kaiserling, Ebert, and others, but by far the most systematic and important inquiry is that of K. Schaum and V. Bellach.

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