scholarly journals Rheologycal properties of sodium carboxymethylcellulose in the presence of electrolyte and mixed micelle of surfactants

2003 ◽  
pp. 71-82 ◽  
Author(s):  
Verica Sovilj ◽  
Petar Dokic ◽  
Lidija Petrovic

One of the most significant aspects of polymer-surfactant interaction, from the practical point of view, is that of rheology control and viscosity enhancement. In the oppositely charged polyelectrolyte-surfactant system strong ionic interaction often leads to precipitation of the formed complex yielding serious problems. In this paper the interaction between anionic polyelectrolyte - sodium carboxymethylcellulose (NaCMC) and cationic surfactant - cethyltrimethylammonium bromide (CTMAB) has been investigated by rheological measurements. Addition of electrolyte NaBr and nonionic surfactant - Tween 80 reduced the binding strength, prevented the precipitation of the complex and increased the viscosity of the system. It was found that rheological properties are strong influenced by NaCMC-CTMAB interaction and the system exhibits either pseudoplastic or thixotropic or rheopectic behavior according to the intensity of interaction.

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles

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.


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

2009 ◽  
Vol 624 ◽  
pp. 1-18 ◽  
Author(s):  
Jean Marc Chaix

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…


2005 ◽  
Vol 13 (3) ◽  
pp. 533-563 ◽  
Author(s):  
Fred Phillips

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.


Exchange ◽  
2005 ◽  
Vol 34 (2) ◽  
pp. 149-166 ◽  
Author(s):  
Henri Gooren

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).


Habarshy ◽  
2021 ◽  
pp. 50-60
Author(s):  
A.B. Myrzhiyeva ◽  
M.Zh Suleimenov ◽  
Uslu Ugur ◽  
A.S. Ibazhanova ◽  
L.O Zhanteliyeva L.O

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.


2014 ◽  
Vol 50 (4) ◽  
pp. 931-941 ◽  
Author(s):  
Ana Ochoa Andrade ◽  
María Emma Parente ◽  
Gastón Ares

Rational design of vaginal drug delivery formulations requires special attention to vehicle properties that optimize vaginal coating and retention. The aim of the present work was to perform a screening of mucoadhesive vaginal gels formulated with carbomer or carrageenan in binary combination with a second polymer (carbomer, guar or xanthan gum). The gels were characterised using in vitroadhesion, spreadability and leakage potential studies, as well as rheological measurements (stress and frequency sweep tests) and the effect of dilution with simulated vaginal fluid (SVF) on spreadability. Results were analysed using analysis of variance and multiple factor analysis. The combination of polymers enhanced adhesion of both primary gelling agents, carbomer and carrageenan. From the rheological point of view all formulations presented a similar behaviour, prevalently elastic and characterised by loss tangent values well below 1. No correlation between rheological and adhesion behaviour was found. Carbomer and carrageenan gels containing the highest percentage of xanthan gum displayed good in vitro mucoadhesion and spreadability, minimal leakage potential and high resistance to dilution. The positive results obtained with carrageenan-xanthan gum-based gels can encourage the use of natural biocompatible adjuvants in the composition of vaginal products, a formulation field that is currently under the synthetic domain.


2018 ◽  
Vol 18 (1) ◽  
pp. 110-132
Author(s):  
Lukas Barth ◽  
Andreas Gemsa ◽  
Benjamin Niedermann ◽  
Martin Nöllenburg

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.


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.


1918 ◽  
Vol 12 (1) ◽  
pp. 96-126 ◽  
Author(s):  
Denys P. Myers

The shade of distinction sought to be shown by the title of this paper may require explanation. Imperfect wording involves either carelessness or ignorance; bad faith indicates dishonesty; nonexecution or disregard implies laxness in the government, if not carelessness; adverse or hostile municipal or judicial action connotes lack of coordination between the internal and external affairs of the State. It follows that such adverse action may be considered from a practical point of view as almost a normal kind of violence against international contracts. It is not to be excused on that account, but it may be considered as a frictional incident almost inseparable under some conditions from the existence of a State. Given either a government of definitely separated elements, such as the United States, or a government without much stability, or a State founded on a type of civilization different from the European order, and this sort of violation of treaty may be forecasted with certainty. Fortunately, however, the instances that cause contractual friction of this sort are of the grosser kinds of personal violence, or are commercial; they are not of a political character, cannot be said to involve policy, and only by a stretch of the imagination involve the tweedledum and tweedledee of international relations, “national honor and vital interest.” They are consequently extremely susceptible to simple and orderly solution.


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