Display omitted
•12.5% and 20% FA-added SCCs emit radon gas above the limit levels.•SF reduced the radon gas emanation of the concretes.•The use of GGBFS in concrete requires sensitivity in terms of ...radioactivity.•FA-added SCCs had the highest annual effective equivalent dose values.•SF against radon gas emanation has presented a preventive and reducing effect.
This study was conducted to investigate the hypothesis that radon gas emanation which is harmful to human health may occur more than standard values in Self-Compacting Concrete (SCC) which has a higher amount of dust material than conventional concretes. The SCCs with 5 %, 12.5 %, and 20 % fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBFS) as well as control concretes without mineral additives were placed closed glass environments with dimensions of 150×150×150 mm; average radon activity concentrations (ARACs) were measured passive method by CR-39 nuclear trace detectors after 7–14-21–28-56–90 and 120 days. Radioactivity analyses including annual effective equivalent dose (AEED) calculation of the concretes were also done. The ARAC values of SCCs increased significantly along with the increase of FA and decreased significantly with the increase of SF. So that the ARAC value (131.56 Bq/m3) of SCC with 20 % FA increased 2.40-fold when compared to the control concrete; however, the ARAC value (14.22 Bq/m3) of SCCs containing 20 % SF was found 4.5-fold lower than the control concrete. 5 % of the concretes containing GGBFS reduced the radon gas emanation; however, the rates of 12.5 % and 20 % increased the emanation. The highest AEEDs for each mineral additive type were 7-day samples including 20 % of FA (8.00 mSv/year), 5 % of GGBFS (3.17 mSv/year) and 5 % of SF (2.16 mSv/year). 12.5 % and 20 % FA-added SCCs emit radon gas above the limit levels. The results have confirmed the hypotheses of the present research depending on the mineral additive type and rate.
The aim of this study is to determine the age and most common reasons of the first dental visit among preschool children, taking into account family income and parental education in Turkey.
This ...cross-sectional study was conducted in a state dental hospital on 519 children aged 0-5 years who had their first dental visit with no previous dental experience. Data on age and reasons for the first dental visit of the children and parent relevant data on family income, educational level, dental visit frequency, and satisfaction about the oral health care information was collected by means of a questionnaire.
Of the 519 children of the study, 47.4% were males and 52.6% were females. The mean age of first dental visit was 3.62±1.32 and 2.9% of the children had been visited under the age of 1 year. Pain (36.4%) was the main reason for the visit followed mostly by check-up (23.1%), other reasons (21.4%), and decay noted by parents (15.6%). There was no referral from paediatricians. Parental educational level was not found as an impact factor for the reasons and the age of the visit (p=0.394; p=0.245). Children of low-income-family were more likely to have dental visit due to pain (p=0.002). The frequency of parents' dental visits was not a determinant factor for the reason and the age of the child's visit (p>0.05; p>0.05). All the parents were satisfied with the oral health information.
It is necessary to raise awareness about early dental visits and oral health care among parents and paediatricians.
The studies of the dynamic behaviors of nonlinear models arising in ocean engineering play a significant role in our daily activities. In this study, we investigate the coupled Boussinesq equation ...which arises in the shallow water waves for two-layered fluid flow. The modified exp
(
-
φ
(
ζ
)
)
-expansion function method is utilized in reaching the solutions to this equation such as the topological kink-type soliton and singular soliton solutions. The interesting 2D and 3D graphics of the obtained analytical solutions in this study are presented. Via one of the reported analytical solutions, the finite forward difference method is used in obtaining the approximate numerical and exact solutions to this equation. The Fourier–Von Neumann analysis is used in checking the stability of the used numerical method with the studied model. The
L
2
and
L
∞
error norms are computed. We finally present a comprehensive conclusion to this study.
This study investigates the Gilson–Pickering equation by using the sine-Gordon expansion method. Sine-Gordon expansion method is one of the most powerful methods for solving the nonlinear partial ...differential equations. We successfully construct various exact solitary wave solutions to the governing equation, such as shock wave, topological, non-topological, compound topological, and non-topological soliton wave solutions. In addition, the stability of the studied nonlinear equation is analyzed via the linear stability analysis. The 2D, 3D, and contour surfaces are also plotted for all obtained solutions.
A comprehensive evaluation of the results obtained according to the measurement of radon gas in buildings and concrete, which is the most consumed material in the world after water, in accessible ...studies carried out in the last 40 years is the main objective of this study. The paper additionally aims to address the gap in the literature by comparatively determining which parameters affect radon–concrete and radon–building relationships. The scientific knowledge compiled within the scope of this article was presented under the main headings of radon and radon gas measurements in concrete and buildings. Radon gas, also known as the “invisible killer”, is considered the second most important cause of lung cancer after smoking (the gas is responsible for 3–14% of lung cancer cases in the world). The results determined that radon concentration limits have been applied in the range of 100–400 Bqm−3 in houses and 100–3700 Bqm−3 in workplaces. Studies conducted on the exhalation rate of radon showed that the radon exhalation rate of concrete may be in the range of 0.23–510 Bqm−2 h−1. The results of indoor radon concentration measurements revealed that values between 4.6 Bqm−3 and 583 Bqm−3 were obtained. Despite the existing literature, some researchers state that there is an urgent need for an improved and widely accepted protocol based on reliable measurement techniques to standardize measurements of the radon exhalation rate of construction materials and the indoor radon concentration of buildings.
In this study, the extended sinh-Gordon equation expansion method is used in constructing various exact solitary wave solutions to the Klein–Gordon–Zakharov equations. The Klein–Gordon–Zakharov ...equations is a nonlinear model describing the interaction between the Langmuir wave and the ion acoustic wave in a high-frequency plasma. We successfully construct some topological, non-topological, compound topological and non-topological, singular, compound singular solitons and singular periodic wave solutions. Under the choice of suitable values of the parameters, the 2D, 3D and contour graphs to some of the reported solutions are also plotted.
Our work aims to investigate the vcBLMPE in
(
3
+
1
)
-dimensions (3D-vcBLMPE) that characterizes wave propagation in incompressible fluids. In real-world issues, nonlinear partial differential ...equations containing time-dependent coefficients are more relevant than those with constant coefficients owing to inhomogeneities of media and nonuniformities of boundaries. In shallow water, linearization of the wave formation needs more critical wave capacity criteria than in water depths, and the strongly nonlinear aspects are readily visible. By using symbolic computation, several nonautonomous wave solutions with different geometric structures are obtained. Each of the gained solutions is presented graphically based on various arbitrary coefficients to demonstrate and better comprehend their dynamical properties. As a comparison between the new results and the results previously reported, we have presented several completely new findings in this study.
Providing oral health care to children from infant to toddler age can be achieved by educating and informing parents about their children's oral health. The aims of this study were to determine the ...basic knowledge of oral health and to evaluate the efficacy of an infant oral health education programme among parents in Turkey.
Study Design: One hundred and fifty parents of infants between 3 and 12 months of age attending the well-baby clinic, Dr. Behcet Uz Children's Hospital (Izmir, Turkey), participated in the study. A pre-test questionnaire was administered to each parent to assess their infant oral health knowledge. The educational intervention was in the form of a 30-minute interactive explanation of a PowerPoint presentation. The parents completed a post-test after the education in the same session (a questionnaire was administered).
The range of correct answers on the pre-test was 7-20 of 26 with a mean of 13.7 (SD=2.76). The range of correct answers on the post-test was 12-26 of 26 with a mean of 21.2 (SD=3.34). The difference of correct responses between before and after education was found to be statistically significant (p<0.01).
Under the conditions of this study, educational presentation improved parents' knowledge on infant oral health care and provided anticipatory guidance.
In this study, the numerical solutions to the KdV equation with dual power nonlinearity by using the finite difference method are obtained. Discretize equation is presented in the form of finite ...difference operators. The numerical solutions are secured via the analytical solution to the KdV equation with dual power nonlinearity which is present in the literature. Through the Fourier–Von Neumann technique and linear stable, we have seen that the FDM is stable. Accuracy of the method is analyzed via the
L
2
and
L
∞
norm errors. The numerical, exact approximations and absolute error are presented in tables. We compare the numerical solutions with the exact solutions and this comparison is supported with the graphic plots. Under the choice of suitable values of parameters, the 2D and 3D surfaces for the used analytical solution are plotted.
.
Couette flows of an incompressible Maxwell fluid with non-integer order derivative without singular kernel due to the motion of a bottom flat plate are analyzed under the slip boundary condition. ...An analytical transform approach is used to obtain the exact expressions for both velocity field and shear stress. Three particular cases from the general results with slip at the wall are obtained. These solutions, which are organized in simple forms in terms of exponential and trigonometric functions, can be conveniently engaged to obtain known solutions from the literature. The control of the new non-integer order derivative on the velocity and shear stress of the fluid is analyzed for some flows with practical applications. The non-integer order derivative with non-singular kernel is more appropriate for handling mathematical calculations of the obtained solutions.
