Iris Publishers Journal Of Engineering Sciences

  Iris Publishers Efficient 2nd Order Taylor Series Expansion Model to Integrate Stiff and Non-Linear ODEs: Comparison to Rk45-Type Integrators Authored   by    Ridha Djebali Abstract A Taylor Series Expansion (TaSE) and three Runge-Kutta RK45 embedded pairs numerical integrators of ordinary differential equations (ODEs) are developed. The TaSE model is designed to solve higher order (>1) ODEs. Validation of TaSE was carried out by help of the RK45 models as well as exact solution for well-chosen stiff test cases. The model implementation and its local and global order of accuracy are investigated. Keywords and Phrases:  Taylor Series Expansion model; RK45 integrators; ODEs; Accuracy; Stiffness; Validation Introduction Historically, it first started with Ludwig Prandtl in 1904 [1] when he gave a seminar at the International Congress of Mathematics in Heidelberg, under the title “Uber Flussigkeitsbewegungen bei sehr kleiner Rei bung”. Prandtl took the fi...

  Iris Publishers DFT study of the Optoelectronic properties of Sn 1 - x A x S  (A= Au and Ag) Solar Cell Applications Authored   by    Zeesham Abbas Abstract Doping effect of transition metal (TM) atoms on the photovoltaic features of Sn1-xAxS (A= Au and Ag) is investigated theoretically. DFT based calculations are used to explore electronic and optical properties by using full potential linearized augmented plane wave (FP-LAPW) method. Furthermore, generalized gradient (GGA) approximation is applied for the treatment of exchange and correlation potential. Ground state properties of these compounds are calculated by using GGA approximation. Our investigation shows that these compounds are metallic in nature. Origin of atomic/orbital electronic states in the energy band dispersion are explored in detail for S, Sn, Au and Ag from the calculated spectra of density of states. Optical parameters like complex dielectric function are also evaluated by using the ...

  Iris Publishers Urban Underground Atlas – Horus Project Authored   by    Stefan Dragos Găitănaru Abstract The urban environment represents a dynamic ecosystem. Most of the economic production for majority of countries is concentrated in the urban areas. The future development is bound to the urban areas capacity to adapt to climate change and social and economic pressures. In the last period more and more scientific and technical papers, projects and committees address the issue of urban climatic resilience and sustainable development. In many cities the demand of space poses significant challenges, as the space needed for developing new functions or relocating and improving existing ones is often not readily available. The understanding of the urban underground represents an ongoing challenge for the scientific community. The Urban Subsurface Atlas it is a new and innovative concept. The innovative aspect of this new atlas comes from the fact that will creat...

  Iris Publishers Directions Developing Quality Management Systems of Mechanical Engineering Enterprises Authored   by    Vavilin Yaroslav Abstract The article deals with the development of the quality management system in the context of changing economic policy and increasing competition. The article considers the main directions of developing integrated management systems in organizations. Keywords:  Quality system; Mechanical engineering; Integration Introduction In conditions of high competition and limited resources (especially financial), the issue of strategy for organizing machinebuilding production to reduce all types of costs and to increase its efficiency, as well as search for competitive advantages becomes relevant [1-5]. Discussion Modern realities of the struggle for the consumer and reduction of all types of costs lead organizations to realize the need not only to create ISM, but also to expand them by introducing various subsystems. The in...