How carbon vacancies can affect the properties of group IV color centers in diamond: A study of thermodynamics and kinetics

Recently there has been much interest in using Group IV elements from the Periodic Table to fabricate and study X$V$ color centers in diamond where X = Si, Ge, Sn, or Pb and $V$ is a carbon vacancy. These Group IV color centers have a number of interesting spin and optical properties which could potentially make them better candidates than N$V^-$ centers for important applications in quantum computing and quantum information processing. Unfortunately, the very same ion implantation process that is required to create these X$V$ color centers in diamond necessarily also produces many carbon vacancies ($V_{\rm C}$) which can form complexes with these color centers ($V_{\rm C}-$X$V$) that can dramatically affect the properties of the isolated X$V$ color centers. The main focus of this work is to use density-functional theory (DFT) to study the thermodynamics and kinetics of the formation of these $V_{\rm C}-$X$V$ complexes and to suggest experimental ways to impede this process such as varying the Fermi level of the host diamond material through chemical doping or applying an external electrical bias. We also include a discussion of how the simple presence of many $V_{\rm C}$ can negatively impact the spin coherence times ($T_2$) of Group IV color centers through the presence of acoustic phonons.Comment: 19 pages, 7 figure

GLIMPSE IN THE WORLD OF DEAF PEOPLE: DEAFNESS AND DEAF EDUCATION

This paper works on the definition of deafness, and who is considered as deaf. The first part of the work talks about the causes of deafness, distinguishing the congenital causes from the acquired causes. Then, the paper analyses the various impacts of hearing loss in the life of deaf people. The second part of the work discusses the issue of deaf education, emphasising the use of sign language as the key means for the development of deaf children literacy skills. The problem raised in this paper is the lack of appropriate knowledge of the mass population on the notion of special education and the needs of persons living with a handicap, especially deaf people, and the paper ends up discussing the issue of special education for deaf learners

FEM analysis applied to the study of stress diffusion in the base plate of steel structures: case of a steel warehouse at Odza in Yaoundé

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Performance du système de santé camerounais dans la protection financière des ménages

Pour contribuer à la performance du système de santé, l’objectif de l’article est d’analyser sur le long terme sa capacité à protéger les ménages  contre les risques financiers liés à la santé. Les deux principales variables étudiées sont l’incidence de la catastrophe financière et l’appauvrissement  des ménages dus aux dépenses de santé, mesurés à partir des données des trois dernières Enquêtes Camerounaises Auprès des Ménages (2001,  2007 et 2014) et selon plusieurs approches pour assurer la robustesse des estimations. Une nette amélioration de la protection financière s’observe  entre 2001-2007 sous la mise en oeuvre des politiques engageant de fortes dépenses sociales. Tandis qu’entre 2007-2014, la situation s’est plutôt  dégradée sous les politiques de croissance inclusives engagées. L’analyse au Cameroun et ailleurs montre que la meilleure performance en matière  de protection financière en santé est plus liée à la gouvernance et à la structure économique qu’à une politique de financement de la santé. Une  bonne combinaison de politiques de financement ciblées est suggérée. Ainsi que le développement d’une économie peu extravertie devant soutenir  un système de santé autonome, doté d’une offre suffisante et de qualité, et avec un système efficient et transparent de mise en oeuvre et  suivi-évaluation. To contribute to the performance of the health system, the objective of the article is to analyse over the long term its ability to protect households  against financial risks related to health. The two main variables studied are the incidence of the financial catastrophe and the impoverishment of  households due to health expenditure. They are measured from data from the last three Cameroonian Household Surveys (2001, 2007 and 2014)  and according to several approaches to ensure the robustness of the estimates. A marked improvement in financial protection can be observed  between 2001-2007 under the implementation of policies involving high social expenditure. While between 2007-2014, the situation rather  deteriorated under the inclusive growth policies undertaken. Analysis in Cameroon and elsewhere shows that the best performance in health  financial protection is more related to governance and economic structure than to health financing policy. A good combination of targeted financing  policies is suggested.  As well as the development of a less extroverted economy to support an autonomous health system, endowed with sufficient and quality supply. The said health system should also have an efficient and transparent system of implementation and monitoring- evaluation

Application of a Mathematical Model to the Analysis of the Influence of Length and Diameter on Log Drying Rate

A mathematical model based on the water potential concept was used to simulate the effect of length and diameter on the drying rate of aspen logs. The moisture content-water potential relationship and the effective water conductivity were determined during independent experiments. The set of equations describing heat and mass transfer during the drying process were solved by the finite element method. As expected, diameters and lengths had a strong effect on log drying rate. Smaller diameter logs dried faster than larger ones. Shorter logs dried faster than longer ones. Over a critical diameter or length value, however, there was no further marked difference in drying rate for larger or longer logs. For a given length, drying was predominantly radial in smaller diameter logs, whereas in larger logs, longitudinal drying was predominant. For longer logs, drying occurred essentially in the radial direction

Moisture Content-Water Potential Relationship of Sugar Maple and White Spruce Wood From Green to Dry Conditions

The moisture content-water potential relationship was determined at 40°C and 60°C for sugar maple (Acer saccharum Marsh.) sapwood and at 60°C for white spruce (Picea glauca (Moench.) Voss.) heartwood from green to dry conditions. The pressure membrane technique was used for high moisture contents and equilibration over salt solutions for low moisture contents. The results show that at high moisture contents, the equilibrium moisture contents obtained from the green condition are lower than those obtained from full saturation (boundary desorption). It is recommended that the sorption history must be taken into account when modeling wood drying. Water potential at a given moisture content increases with temperature. There is a characteristic plateau in the green moisture content-water potential relationship obtained for sugar maple at water potentials between -2,000 and -6,000 J kg-1, which can be attributed to its heterogeneous capillary structure. The maximum concentration of effective pore radius occurs at 0.02 μm in the case of sugar maple, corresponding to the size of the pit membrane openings