@misc{ThompsonZelnerNhuetal., author = {Thompson, Corinne N. and Zelner, Jonathan L. and Nhu, Tran Do Hoang and Phan, Vu Tra My and Phuc, Hoang Le and Hung, Nguyen Thanh and Duong, Vu Thuy and Ngoc, Minh Nguyen and Tuan, Ha Manh and Tu, Van Hoang Minh and Vi, Lu Lan and Chau, Nguyen Van Vinh and Hien, Tran Tinh and Clemm, Emmiliese von and Storch, Harry and Thwaites, Guy and Grenfell, Bryan T. and Baker, Stephen}, title = {The impact of environmental and climatic variation on the spatiotemporal trends of hospitalized pediatric diarrhea in Ho Chi Minh City, Vietnam}, series = {Health \& Place}, journal = {Health \& Place}, number = {35}, issn = {1353-8292}, doi = {10.1016/j.healthplace.2015.08.001}, pages = {147 -- 154}, abstract = {It is predicted that the integration of climate-based early warning systems into existing action plans will facilitate the timely provision of interventions to diarrheal disease epidemics in resource-poor settings. Diarrhea remains a considerable public health problem in Ho Chi Minh City (HCMC), Vietnam and we aimed to quantify variation in the impact of environmental conditions on diarrheal disease risk across the city. Using all inpatient diarrheal admissions data from three large hospitals within HCMC, we developed a mixed effects regression model to differentiate district-level variation in risk due to environmental conditions from the overarching seasonality of diarrheal disease hospitalization in HCMC. We identified considerable spatial heterogeneity in the risk of all-cause diarrhea across districts of HCMC with low elevation and differential responses to flooding, air temperature, and humidity driving further spatial heterogeneity in diarrheal disease risk. The incorporation of these results into predictive forecasting algorithms will provide a powerful resource to aid diarrheal disease prevention and control practices in HCMC and other similar settings.}, language = {en} } @misc{RepetckiiVinhBeirow, author = {Repetckii, Oleg V. and Vinh, Nguyen Van and Beirow, Bernd}, title = {Sensitivity Analysis Regarding the Impact of Intentional Mistuning on Blisk Vibrations}, series = {Mechanisms and Machine Science}, volume = {125}, journal = {Mechanisms and Machine Science}, publisher = {Springer}, address = {Cham}, issn = {2211-0992}, doi = {10.1007/978-3-031-15758-5_41}, pages = {408 -- 415}, abstract = {The effect of different intentional mistuning (IM) patterns is investigated with respect to the forced response of an academic axial blisk. It could be shown in numerical analyses that a preliminary use of sensitivity algorithms helps to understand the feasibility and efficiency of introducing geometric changes of the blades. The implementation of IM patterns requires conducting intensive sensitivity studies based on FE simulations in order to identify the consequences of slight geometrical blade modifications on natural frequencies. Typical changes might be a modification of fillet radii or partial modifications of blade thickness, which are most suitable to adjust a target natural frequency without a severe loss of aerodynamic performance. A software tool developed at Irkutsk SAU is employed to evaluate the impact of mass and stiffness contributions, and with that, geometric deviations on blade natural frequencies. Intensive blade vibration due to aerodynamic excitation of blisks is known as major source of high cycle fatigue, which may cause severe failures of turbine and compressor wheels during operation. The problem is relevant for several sectors of industry such as power generation, aviation or vehicle manufacturing. In consequence, there is a broad request of preventing any inadmissible vibration at any time. The application of IM can be regarded as powerful tool to avoid both, large forced responses and self-excited vibration. However, there is a lack of knowledge about how to implement mistuning without strong distortions of the flow passage. The main objective of this work is to close this gap based on comprehensive numerical analyses with regard to the effects of intended geometric modifications of blades on modal quantities. Using FE models, the effectiveness of the proposed block models of mistuning is analyzed with and without taking into account the operational speed of the axial impeller. In conclusion, the consequences of different IM implementations on the forced response of an academic blisk are discussed. In particular, the most promising IM patterns are identified yielding the least forced response.}, language = {en} }