scholarly journals Modification of surface hydrophilicity of dental materials by ozone

2019 ◽  
Vol 31 (2) ◽  
pp. 117
Author(s):  
Ira Artilia
Keyword(s):  
Mechanical Property ◽  
Cement Paste ◽  
Dental Materials ◽  
Reducing Agent ◽  
Cement Industry ◽  
Gas Treatment ◽  
New Approach ◽  
Cement Powder ◽  
Long Time ◽  
Apatite Cement

Introduction: Gypsum, Portland, and apatite cement, and gypsum have been developed as dental materials for a long time. Similarity of the three materials leads to some relevant approaches to improve the characteristic of dental materials. Water reducing agent is commonly used in detergent or soap and also used as a conventional method in the cement industry to increase the handling and mechanical property. Cement paste mixed with water reducing agent is more flowable (ease handling), and the set mass is harder (mechanical property increased). However, it has a problem with biomaterial cement due to the biocompatibility. This water reducing agent is harmful to living tissue. Therefore, a new approach will be demonstrated in this research. Methods: In this study, the hydrophilicity of cement powder was modified by ozone gas treatment. Ozone gas treatment will be applied to modify the hydrophilicity of cement particles; therefore, it can act similar to the water reducing agent. Results: The hydrophilicity of gypsum, Portland, and apatite cement powder was significantly increased after ozone gas treatment. The hydrophilicity improvement of cement powder increased the ability of water to interact with the cement powder. The benefit is the flowability improvement of cement paste. Therefore, the manipulation index would also be increased. The mechanical property would be increased because the water added for manipulation was decreasing. Conclusion: Ozone gas treatment could improve the hydrophilicity of gypsum, Portland, and apatite cement powder.Keywords: Gypsum, Portland, apatite cement, hydrophilic, ozone

Inter-country inequality as a dynamic process and the problem of post-industrial development

2018 ◽  
pp. 5-29 ◽  
Author(s):  
L. M. Grigoryev ◽  
V. A. Pavlyushina
Keyword(s):  
Economic Growth ◽  
Political Institutions ◽  
Industrial Development ◽  
Modern World ◽  
New Approach ◽  
Development Level ◽  
The World ◽  
Long Time ◽  
The Difference ◽  
Post Industrial

The phenomenon of economic growth is studied by economists and statisticians in various aspects for a long time. Economic theory is devoted to assessing factors of growth in the tradition of R. Solow, R. Barrow, W. Easterly and others. During the last quarter of the century, however, the institutionalists, namely D. North, D. Wallis, B. Weingast as well as D. Acemoglu and J. Robinson, have shown the complexity of the problem of development on the part of socioeconomic and political institutions. As a result, solving the problem of how economic growth affects inequality between countries has proved extremely difficult. The modern world is very diverse in terms of development level, and the article offers a new approach to the formation of the idea of stylized facts using cluster analysis. The existing statistics allows to estimate on a unified basis the level of GDP production by 174 countries of the world for 1992—2016. The article presents a structured picture of the world: the distribution of countries in seven clusters, different in levels of development. During the period under review, there was a strong per capita GDP growth in PPP in the middle of the distribution, poverty in various countries declined markedly. At the same time, in 1992—2016, the difference increased not only between rich and poor groups of countries, but also between clusters.

scholarly journals Online Social Gambling and Its Implications for the Study of Marketing Communications

2015 ◽  
Vol 4 (3) ◽  
pp. 22-50 ◽  
Author(s):  
Wilson Ozuem ◽  
Jason Prasad
Keyword(s):  
Single Case ◽  
Internet Technology ◽  
Marketing Communication ◽  
Single Case Study ◽  
New Approach ◽  
Real Money ◽  
Long Time ◽  
Ancient Times ◽  
Communication Practices

Gambling has been a part of humanity for a long time, and references to it have been found in some of the earliest dated records. Literature on the topic has been accumulating since ancient times. The advent of Internet technology along with its typical subsets provides a new approach to how gambling is conducted in postmodern times. Drawing on qualitative research and utilising a single case study strategy, this study examines online social gambling and real money gambling marketing communication practices as well as offers some insights into the development and implementation of effective marketing communication programmes. In contrast to existing studies, the paper, in part, proposes integrative and higher levels of marketing communication programmes between online social gambling and real money gambling environments.

scholarly journals IMPLEMENTASI CONTEXT AWARE PADA SISTEM TRAVEL PLANNER BERBASIS MOBILE

2021 ◽  
Vol 5 (1) ◽  
pp. 23-27
Author(s):  
Viery Darmawan ◽  
◽  
Rengga Asmara ◽  
Ira Prasetyaningrum
Keyword(s):  
Contextual Information ◽  
The Internet ◽  
Context Aware ◽  
New Approach ◽  
Tourist Attractions ◽  
Technological Advances ◽  
Long Time ◽  
Travel Efficiency ◽  
Opening And Closing

In the era of technological advances, tourists will first seek information about the tourist object to be addressed, even tourists often don't have a destination, so they have to search one by one via the internet. In determining travel plans, it is often to see one by one the review of tourist attractions and conclude the results will take a long time, while tourists need actual and fast information to determine the travel plans. In this study, the authors take a new approach, namely by creating a mobile-based travel planner system that compiles travel plans automatically by considering contextual information related to tourist location points, whether of tourist locations during travel days, travel opening and closing hours, so that it will increase travel efficiency without having to do the research manually which takes a long time. The system can also provide travel recommendations based on visitor comments sentiment on Google Places and is equipped with a trip route that will be generated automatically. This research is useful for helping tourists plan their trip actually because of the consideration of contextual information so that it will make it easier and save tourists time.

scholarly journals Date canning: a new approach for the long time preservation of date

2014 ◽  
Vol 52 (4) ◽  
pp. 1872-1880 ◽  
Author(s):  
Aziz Homayouni ◽  
Aslan Azizi ◽  
Ata Khodavirdivand Keshtiban ◽  
Amir Amini ◽  
Ahad Eslami
Keyword(s):  
New Approach ◽  
Long Time

Long-time monitoring of the microstructural change in hardening cement paste by SANS

1997 ◽  
Vol 9 (36) ◽  
pp. 139-147 ◽  
Author(s):  
F. Häussler ◽  
M. Hempel ◽  
H. Baumbach
Keyword(s):  
Cement Paste ◽  
Microstructural Change ◽  
Long Time

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

2018 ◽  
Vol 34 ◽  
pp. 48-58 ◽  
Author(s):  
Karima Arroudj ◽  
Saida Dorbani ◽  
Mohamed Nadjib Oudjit ◽  
Arezki Tagnit-Hamou
Keyword(s):  
Mechanical Strength ◽  
Calcium Hydroxide ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Heat Of Hydration ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Natural Mineral ◽  
Different Ages

Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.

RENORMALIZATION AND ASYMPTOTICS

2000 ◽  
Vol 14 (12n13) ◽  
pp. 1327-1361 ◽  
Author(s):  
Y. OONO
Keyword(s):  
Renormalization Group ◽  
Differential Equations ◽  
Perturbation Methods ◽  
Explicit Calculation ◽  
Group Approach ◽  
New Approach ◽  
Asymptotic Behaviors ◽  
Singular Perturbation Methods ◽  
Renormalization Group Approach ◽  
Long Time

After a gentle introduction to the Stückelberg–Petermann style (i.e. field-theoretical) renormalization group (RG) theory, its application to the study of asymptotic behaviors of differential equations is explained through simple examples. The essence of singular perturbation methods to study asymptotic behaviors of differential equations is to reduce it to equations governing long time scale behaviors (i.e. the so-called reductive perturbation). The RG approach gives the reduced equation as an RG equation (this is called the reductive renormalization group approach). Once the RG equation is written down, the asymptotic behavior can be obtained by solving it. The RG equation also facilitates the error analysis of the asymptotic solutions. A new approach via "proto-RG equation" explained in this article further simplifies the reductive use of RG. For example, to the lowest nontrivial order the approach does not require any explicit calculation of perturbative results.

Effect of Naphthalene Compounded Superplasticizer on Strength and Shrinkage of Ready-Mixed Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 488-495
Author(s):  
Yu Fei Wang ◽  
Han Dong Yan
Keyword(s):  
Cement Paste ◽  
Test Data ◽  
Concrete Strength ◽  
Reducing Agent ◽  
The Other ◽  
General Rules ◽  
Early Strength ◽  
Ready Mixed Concrete ◽  
Mixed Concrete

Superplasticizer is widespread applied in the ready-mixed concrete in China. In the specific engineering, it is not only has the requirement of water-reducing ratio for superplasticizer, but also the superplasticizer has to meet the demand such as early-strength, air-entraining, retarding and so on. In current, the naphthalene compounded superplasticizer is conducted on the basis of the FDN modification. This paper selects two kinds of representative naphthalene compounded superplasticizers, one is the setretarder superplasticizer (WRA1), and the other one is the early strength-air entraining-retarding superplasticizer (WRA2). The effect of performance on neat cement paste, mortar and concrete which mixed with the two admixtures are compared with the benchmarks (not mixed with water reducing agent) and mixed with FDN. Through the analysis and comparison of the test data, the general rules of the naphthalene compounded superplasticizer to concrete strength and shrinkage are put forward in this paper. Also, according to those rules, it poses the concrete problems to be noted in the production. This may have guidance for reducing the early cracks of ready-mixed concrete.

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