Priprava nekoliko novih piridina, tienopiridina i pirido[2,3:4\u27,5\u27]tieno[3\u27,2\u27-d]pirimidin-8-ona iz 2-acetilbenzoimidazola

Reaction of 2-acetylbenzoimidazole 1 with some arylaldehydes under different conditions gave chalcones, 1,5-pentanediones and pyridines. Treatment of chalcones with various types of reagents gave the corresponding new pyridines, thienopyridines, pyrido[2,3:4\u27,5\u27]thieno[3\u27,2\u27-d]- pyrimidin-8-ones via initial addition of active methylene or amino group to the double bond followed by cyclization.Reakcija 2-acetilbenzoimidazola s nekim arilaldehidima pod razli~itim uvjetima daje halkon, 1,5-pentandione i piridine. Obrada halkona s razli~itim reagensima daje nove piridine, tienopiridine i pirido[2,3:4\u27,5\u27]ti -eno[3\u27,2\u27-d]pirimidin-8-one preko po~etne adicije metilena ili amino grupe na dvostruku vezu i nakon toga slijedi ciklizacija

Numerical study of perforated obstacles effects on the performance of solar parabolic trough collector

The current work presents and discusses a numerical analysis of improving heat transmission in the receiver of a parabolic trough solar collector by introducing perforated barriers. While the proposed approach to enhance the collector’s performance is promising, the use of obstacles results in increased pressure loss. The Computational Fluid Dynamics (CFD) model analysis is conducted based on the renormalization-group (RNG) k-ɛ turbulent model associated with standard wall function using thermal oil D12 as working fluid The thermo-hydraulic analysis of the receiver tube with perforated obstacles is taken for various configurations and Reynolds number ranging from 18,860 to 81,728. The results are compared with that of the receiver without perforated obstacles. The receiver tube with three holes (PO3) showed better heat transfer characteristics. In addition, the Nusselt number (Nu) increases about 115% with the increase of friction factor 5–6.5 times and the performance evaluation criteria (PEC) changes from 1.22 to 1.24. The temperature of thermal oil fluid attains its maximum value at the exit, and higher temperatures (462.1 K) are found in the absorber tube with perforated obstacles with three holes (PO3). Accordingly, using perforated obstacles receiver for parabolic trough concentrator is highly recommended where significant enhancement of system’s performance is achieved

Getting It Right the First Time: Defining Regionally Relevant Training Curricula and Provider Core Competencies for Point-of-Care Ultrasound Education on the African Continent

Significant evidence identifies point-of-care ultrasound (PoCUS) as an important diagnostic and therapeutic tool in resource-limited settings. Despite this evidence, local health care providers on the African continent continue to have limited access to and use of ultrasound, even in potentially high-impact fields such as obstetrics and trauma. Dedicated postgraduate emergency medicine residency training programs now exist in 8 countries, yet no current consensus exists in regard to core PoCUS competencies. The current practice of transferring resource-rich PoCUS curricula and delivery methods to resource-limited health systems fails to acknowledge the unique challenges, needs, and disease burdens of recipient systems. As emergency medicine leaders from 8 African countries, we introduce a practical algorithmic approach, based on the local epidemiology and resource constraints, to curriculum development and implementation. We describe an organizational structure composed of nexus learning centers for PoCUS learners and champions on the continent to keep credentialing rigorous and standardized. Finally, we put forth 5 key strategic considerations: to link training programs to hospital systems, to prioritize longitudinal learning models, to share resources to promote health equity, to maximize access, and to develop a regional consensus on training standards and credentialing