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MELESSE, WONDWOSEN GEBEYAW,TIRUNEH, AWOKE ANDARGIE,DERESE, GETACHEW ADAMU The Korean Society for Computational and Applied M 2020 Journal of applied mathematics & informatics Vol.38 No.1
In this paper, a class of linear second order singularly perturbed delay differential turning point problems containing a small delay (or negative shift) on the reaction term and when the solution of the problem exhibits twin boundary layers are examined. A hybrid finite difference scheme on an appropriate piecewise-uniform Shishkin mesh is constructed to discretize the problem. We proved that the method is almost second order ε-uniformly convergent in the maximum norm. Numerical experiments are considered to illustrate the theoretical results.
Wondwosen Gebeyaw Melesse,Awoke Andargie Tiruneh,Getachew Adamu Derese 한국전산응용수학회 2020 Journal of applied mathematics & informatics Vol.38 No.1
In this paper, a class of linear second order singularly perturbed delay differential turning point problems containing a small delay (or negative shift) on the reaction term and when the solution of the problem exhibits twin boundary layers are examined. A hybrid finite difference scheme on an appropriate piecewise-uniform Shishkin mesh is constructed to discretize the problem. We proved that the method is almost second order ε-uniformly convergent in the maximum norm. Numerical experiments are considered to illustrate the theoretical results.
DIRECT PRODUCT, SUBDIRECT PRODUCT, AND REPRESENTABILITY IN AUTOMETRIZED ALGEBRAS
Gebrie Yeshiwas Tilahun,Radhakrishna Kishore Parimi,Mulugeta Habte Melesse The Kangwon-Kyungki Mathematical Society 2023 한국수학논문집 Vol.31 No.4
The paper introduces the concept of direct product and discusses some basic facts about distant ideals. We also introduce the definition of directly indecomposable in an autometrized algebra. Furthermore, we present the concept of a subdirect product and simple autometrized algebra and its behavior. We also introduce the definition of subdirectly irreducible in an autometrized algebras. In particular, we prove that every subdirectly irreducible monoid autometrized algebra is directly indecomposable. Finally, we discuss different properties of chain autometrized algebras and introduce the representability in the autometrized algebra. We also prove that if a weak chain monoid normal autometrized l-algebra is nilradical, then it is representable.
Saïdou,Shinji Tokonami,Masahiro Hosoda,Augustin Simo,Joseph Victor Hell,Olga German,Esmel Gislere Oscar Meless 대한방사선방어학회 2022 방사선방어학회지 Vol.47 No.4
Background : The current study reports measurements of activity concentrations of radon (222Rn) and thoron (220Rn) in dwellings , followed by inhalation dose assessment of the public , and then by the development of regulation and the national radon action plan (NRAP) in Cameroon . Materials and Methods : Radon , thoron , and thoron progeny measurements were carried out from 2014 to 2017 using radon-thoron discriminative detectors (commercially RADUET) in 450 dwellings and thoron progeny monitors in 350 dwellings . From 2019 to 2020 , radon track detectors (commercially RADTRAK) were deployed in 1 , 400 dwellings . It was found that activ- ity concentrations of radon range in 1 , 850 houses from 10 to 2 , 620 Bq/m3 with a geometric mean of 76 Bq/m3 . Results and Discussion : Activity concentrations of thoron range from 20 to 700 Bq/m3 with a geometric mean of 107 Bq/m3 . Thoron equilibrium factor ranges from 0 . 01 to 0 . 6 , with an arithmetic mean of 0 . 09 that is higher than the default value of 0 . 02 given by UNSCEAR . On average , 49% , 9% , and 2% of all surveyed houses have radon concentrations above 100 , 200 , and 300 Bq/m3 , respectively. The average contribution of thoron to the inhalation dose due to radon and thoron exposure is about 40% . Thus , thoron cannot be neglected in dose assessment to avoid biased results in radio-epidemiological studies . Only radon was considered in the drafted regulation and in the NRAP adopted in October 2020 . Reference levels of 300 Bq/m3 and 1 , 000 Bq/m3 were recommended for dwellings and workplaces . Conclusion : Priority actions for the coming years include the following : radon risk mapping , promotion of a protection policy against radon in buildings , integration of the radon prevention and mitigation into the training of construction specialists , mitigation of dwellings and workplaces with high radon levels , increased public awareness of the health risks associated with radon , and development of programs on the scientific and technical aspects .