Optimal parameters of dynamic vibration absorber for linear damped rotary systems subjected to harmonic excitation

Dynamic vibration absorber (DVA) is a simple and effective device for vibration absorption used in many practical applications. Determination of suitable parameters for DVA is of significant importance to achieve high vibration reduction effectiveness. This paper presents a method to find the optimal parameters of a DVA attached to a linear damped rotary system excited by harmonic torque. To this end, a closed-form formula for the optimum tuning parameter is derived using the fixed-point theory based on an assumption that the damped rotary systems are lightly or moderately damped. The optimal damping ratio of DVA is found by solving a set of non-linear equations established by the Chebyshev's min-max criterion. The performance of the proposed optimal DVA is compared with that obtained by existing optimal solution in literature. It is shown that the proposed optimal parameters allow to obtain superior vibration suppression compared to existing optimal formula. Extended simulations are carried out to examine the performance of the optimally designed DVA and the sensitivity of the optimum parameters. The simulation results show that the improvement of the vibration performance on damped rotary system can be as much as 90% by using DVA

Methodology of determining effective porosity and longitudinal dispersivity of aquifer and the application to field tracer injection test in Southern Hanoi, Vietnam

Groundwater field pumping out and tracer injection test had been carried out at Nghiem Xuyen commune, Thuong Tin district, Hanoi where salinized and fresh groundwater boundary exist in the Pleistocene aquifer. The test was executed with pumping out rate of 9l/sec and tracer injection rate of 0.7l/sec of water with the salt concentration of 5g/l. The interpretation and analysis of the groundwater solute transport parameters by the field pumping out and tracer injection test is a rather complicated and delicate task due to the variability of the temporal boundary conditions. The test results have shown that although the tracer injection time is rather long (up to 60 hours), the tracer breakthrough curve of the tracer concentration of the pumped out water has its very specific characteristic shape, however with some variation due to the test invisible variability of conditions. The results of the parameter identification based on the method of least squares have given effective porosity of 0.32 and longitudinal dispersivity of 2.5m (which give the hydrodynamic dispersion of from D=250m2/day right outside the pumping well screen to D=18m2/day right outside the injection well screen). The minimal sum of squares of the differences between the observed and model normalized tracer concentration is 0.00119, which is corresponding to the average absolute difference between observed and model normalized concentrations of 0.0355 (while 1 is the worse and 0 is the best). The results have also shown that the maximal tracer concentration right outside the pumping out well screen is 6.1 times greater than the tracer concentration of the pumped out water. The distortion flow coefficient αW (the ratio between the flow rate through the injection well section without its presence) and the groundwater flow into the tracer injection well is from 18.66 (at the early testing time) to 10.76 (at the later testing time).References Bear J. and Verruijt A., 1987. Modeling groundwater flow and pollution, D. Reidel Publishing Company, Dordrecht, Holand, 414pp. Brouyère S. 2008. Modeling tracer injection and well-aquifer interactions: a new mathematical and numerical approach. Water Resour. Res, 39(3), 1070-1075. Drost, W., D. Klotz, A. Koch, H. Moser, F. Neumaier, and W. Rauert, 1968. Point dilution methods of investigating ground water flow by means of radioisotopes. Water Resour. Res., 4(1), 125-146. Fetter C.W., 2001. Applied Hydrogeology. Prentice Hall Inc. New Jersey 07458, 598pp. Hall, S.H., 1996. Practical single-well tracer methods for aquifer testing, In: Tenth National Outdoor Action Conference and Exposition, National Groundwater Association, Colombus, Ohio, USA, 11pp. Huyakorn P.S., and Pinder G. F., 1983. Computational Methods in Subsurface Flow. Academic Press, New York, 473pp. Nguyen Van Hoang, 2016. Modeling of pollutant transport in water environment. Vietnam Academy of Science and Technology Publishers, 201pp. Nguyen Van Hoang (project head) (2014-2017). Science and Technology Proposal: Study on the finite element modeling software for simulation of groundwater flow and solute transport by groundwater-application to aquifer in Central plain of Vietnam" codded ĐT.NCCB-ĐHƯD.2012-G/04 supported by NAFOSTED-MOST. Nguyen Van Hoang, Dinh Van Thuan, Nguyen Duc Roi, Le Duc Luong, 2012. Study on the impact of the Tri An reservoir on its downstream groundwater level regime. Vietnam Journal of Earth Sciences, 34(4), 465-476. Nguyen Van Hoang, Pham Lan Hoa, Le Thanh Tung, 2014. Study on the accuracy of the numerical modeling of the groundwater movement due to spatial and temporal discretization. Vietnam Journal of Earth Sciences, 36(4), 424-431. Nguyen Van Hoang and Nguyen Duc Roi, 2015. Finite element method in estimation of lag time of rainfall recharge to Holocene groundwater aquifer in Hung Yen province. Vietnam Journal of Earth Sciences, 37(4), 355-362. Nguyen Van Hoang, Nguyen Thanh Cong, Pham Lan Hoa, Le Thanh Tung, 2016. Study on the characteristics of salinity transport in 2D cross-section unconfined aquifer. Vietnam Journal of Earth Sciences, 38(1), 66-78. Novakowski, K.S., 1992. An evaluation of boundary conditions for one-dimensional solute transport, 1, Mathematical development. Water Resour. Res., 28(9), 2399-2410. Polubarinova-Kotrina P. IA., 1977. Theory of Groundwater. Moscow Science Publishers. 664pp. Tong Thanh Tung, 2015. Specialized report: Interpretation and analysis of aquifer parameters for pumping test at group-well test CHN5 in Nghiem Xuyen-Thuong Tin-Hanoi. Project "Groundwater protection in large cities (city: Hanoi)". Vietnam National Center for Water Resources Planning and Investigation-MoNRE, 16pp. Trieu Duc Huy (Project head), 2015. Science and Technology Proposal: Groundwater protection in large cities (city: Hanoi) approved by MoNRE Minister in Decision 1557/QD-BTNMT dated 30th Aug. 2013. Vietnam National Center for Water Resources Planning and Investigation-MoNRE. Vitaly A. Zlotnik and John David Logan, 1996. Boundary Conditions for Convergent Radial Tracer Tests and Effect of Well Bore Mixing Volume. Papers in the Earth and Atmospheric Sciences,  159pp. Zienkiewicz O. C. and Morgan K., 1983. Finite Elements and Approximation. Academic Press, 328p.

Circulating Biomarkers for Early Diagnosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, which is also often fatal. An early and accurate diagnosis is a decisive step towards the survival of the patients. Molecular biology improved significantly the prognosis of liver cancers through learned use of tumor markers like proteantigens, cytokines, enzymes, isoenzymes, circulating RNAs, gene mutations and methylations. Nevertheless, much improvement is still achievable and needed in this area, which is crucial in order to make an early diagnosis and monitor the progression of the disease. We present in this review what we believe to be the most relevant data regarding tissue and serum biomarkers related to HCC

ỨNG DỤNG CÔNG NGHỆ VIỄN THÁM VÀ GIS NGHIÊN CỨU QUÁ TRÌNH DỊCH CHUYỂN ĐƯỜNG BỜ VÀ ĐÓNG/MỞ CỬA ĐẦM Ô LOAN (PHÚ YÊN) GIAI ĐOẠN 1965 - 2014

Application of remote sensing and GIS (Geographic Information System) technologies found that: Fluctuation process of shoreline in O Loan lagoon became evident, through which a general picture of the shoreline development in a long time from 1965 - 2014 has been launched. The process of erosion - accretion evolutions occurred time by time. In which, the period from 1965 - 1995 was the process of erosion - accretion and gradual northward movement of O Loan lagoon inlet, with erosion area greater than deposition area. The period after 1995 was the process of erosion and An Hai inlet opening during rainy season, coincident with northeast monsoon and typhoon activity; and the process of accretion and An Hai inlet closing during dry season, coincident with southwest monsoon.Trên cơ sở ứng dụng công nghệ viễn thám và GIS (hệ thông tin địa lý) cho thấy: Quá trình biến động của đường bờ biển khu vực đầm Ô Loan được thể hiện rõ rệt, qua đó đã đưa ra bức tranh tổng quát về quá trình phát triển của đường bờ, trong một thời gian dài từ năm 1965 - 2014. Các quá trình xói lở - bồi tụ diễn biến theo thời gian. Trong đó, thời kỳ từ năm 1965 - 1995 là các quá trình xói lở - bồi tụ và dịch chuyển cửa biển đầm Ô Loan dần lên phía bắc, với diện tích bị xói lở lớn hơn diện tích được bồi tụ. Thời kỳ từ sau năm 1995 đến nay là quá trình xói lở và mở cửa biển An Hải chủ yếu xảy ra vào mùa mưa, trùng với thời kỳ gió mùa Đông Bắc và bão hoạt động, còn bồi lấp cửa biển xảy ra vào mùa khô, trùng với thời kỳ gió mùa Tây Nam

Priorities for primary health care policy implementation:Recommendations from the combined experience of six countries in the Asia-Pacific

Primary health care is essential for equitable, cost-effective and sustainable health care. It is the cornerstone to achieving universal health coverage against a backdrop of rising health expenditure and aging populations. Implementing strong primary health care requires grassroots understanding of health system performance. Comparing successes and barriers between countries may help identify mutual challenges and possible solutions. This paper compares and analyses primary health care policy in Australia, Malaysia, Mongolia, Myanmar, Thailand and Vietnam. Data were collected at the World Organization of National Colleges, Academies and Academic Associations of General Practitioners/Family Physicians (WONCA) Asia-Pacific regional conference in November 2017 using a predetermined framework. The six countries varied in maturity of their primary health care systems, including the extent to which family doctors contribute to care delivery. Challenges included an insufficient trained and competent workforce, particularly in rural and remote communities, and deficits in coordination within primary health care, as well as between primary and secondary care. Asia-Pacific regional policy needs to: (1) focus on better collaboration between public and private sectors; (2) take a structured approach to information sharing by bridging gaps in technology, health literacy and interprofessional working; (3) build systems that can evaluate and improve quality of care; and (4) promote community-based, high-quality training programs

An Introduction to EEG Source Analysis with an illustration of a study on Error-Related Potentials

International audienceOver the last twenty years blind source separation (BSS) has become a fundamental signal processing tool in the study of human electroencephalography (EEG), other biological data, as well as in many other signal processing domains such as speech, images, geophysics and wireless communication (Comon and Jutten, 2010). Without relying on head modeling BSS aims at estimating both the waveform and the scalp spatial pattern of the intracranial dipolar current responsible of the observed EEG, increasing the sensitivity and specificity of the signal received from the electrodes on the scalp. This chapter begins with a short review of brain volume conduction theory, demonstrating that BSS modeling is grounded on current physiological knowledge. We then illustrate a general BSS scheme requiring the estimation of second-order statistics (SOS) only. A simple and efficient implementation based on the approximate joint diagonalization of covariance matrices (AJDC) is described. The method operates in the same way in the time or frequency domain (or both at the same time) and is capable of modeling explicitly physiological and experimental source of variations with remarkable flexibility. Finally, we provide a specific example illustrating the analysis of a new experimental study on error-related potentials

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13