3,991 research outputs found
A Transfer Function Representation of Thermo-Acoustic Dynamics for Combustors
In this paper, we present a transfer function
representation of a general one-dimensional combustor. The input
of the transfer function is a heat rate perturbation of a burner and
the output is a flow velocity perturbation at the burner. This paper
considers a general combustor model composed of multiple cans with
different cross sectional areas, along with a non-zero flow rate
Broadcasting Stabilization for Dynamical Multi-Agent Systems
This paper deals with a stabilization problem for multi-agent systems, when all agents in a multi-agent system receive the same broadcasting control signal and the controller can measure not each agent output but the sum of all agent outputs. It is analytically shown that when the sum of all agent outputs is bounded with a certain broadcasting controller for a given reference, each agent output is separately bounded:stabilization of the sum of agent outputs always results in the stability of every agent output. A numerical example is presented to illustrate our theoretic findings in this paper
Broadcasting Stabilization for Dynamical Multi-Agent Systems
This paper deals with a stabilization problem for multi-agent systems, when all agents in a multi-agent system receive the same broadcasting control signal and the controller can measure not each agent output but the sum of all agent outputs. It is analytically shown that when the sum of all agent outputs is bounded with a certain broadcasting controller for a given reference, each agent output is separately bounded:stabilization of the sum of agent outputs always results in the stability of every agent output. A numerical example is presented to illustrate our theoretic findings in this paper
Microstructure and High Temperature Deformation Behavior of Cast 310S Alloy
High temperature deformation behavior of cast 310S stainless steel has been investigated in this study by performing tensile and compression tests at temperatures from 900 to 1200°C. Rectangular ingots of which the dimensions were 350×350×100 in millimeter were cast using vacuum induction melting. Phase equilibrium was calculated using the FactSage®, thermodynamic software and database. Thermal expansion coefficient was also measured on the ingot in the temperature range from room temperature to 1200°C. Tensile strength of cast 310S stainless steel was 9 MPa at 1200°C, which is a little higher than that of a wrought 310S. With temperature decreased, tensile strength increased rapidly and reached up to 72 MPa at 900°C. Elongation also increased with temperature decreased. Microstructure observation revealed that σ phase was precipitated along the grain boundary and within the matrix over 1200°C, which is detrimental to high temperature elongation
Microstructure and High Temperature Deformation Behavior of Cast 310S Alloy
High temperature deformation behavior of cast 310S stainless steel has been investigated in this study by performing tensile and compression tests at temperatures from 900 to 1200°C. Rectangular ingots of which the dimensions were 350×350×100 in millimeter were cast using vacuum induction melting. Phase equilibrium was calculated using the FactSage®, thermodynamic software and database. Thermal expansion coefficient was also measured on the ingot in the temperature range from room temperature to 1200°C. Tensile strength of cast 310S stainless steel was 9 MPa at 1200°C, which is a little higher than that of a wrought 310S. With temperature decreased, tensile strength increased rapidly and reached up to 72 MPa at 900°C. Elongation also increased with temperature decreased. Microstructure observation revealed that σ phase was precipitated along the grain boundary and within the matrix over 1200°C, which is detrimental to high temperature elongation
Depressed Neuronal Growth Associated Protein (GAP)-43 Expression in the Small Intestines of Mice Experimentally Infected with Neodiplostomum seoulense
Neodiplostomum seoulense (Digenea: Neodiplostomidae) is an intestinal trematode that can cause severe mucosal pathology in the small intestines of mice and even mortality of the infected mice within 28 days after infection. We observed neuronal growth associated protein-43 (GAP-43) expression in the myenteric plexus of the small intestinal wall of N. seoulense-infected mice until day 35 post-infection (PI). BALB/c mice were infected with 200 or 500 N. seoulense metacercariae isolated from naturally infected snakes and were killed every 7 days for immunohistochemical demonstration of GAP-43 in the small intestines. N. seoulense-infected mice showed remarkable dilatation of intestinal loops compared with control mice through days 7-28 PI. Conversely, GAP-43 expression in the mucosal myenteric plexus was markedly (P<0.05) reduced in the small intestines of N. seoulense-infected mice during days 7-28 PI and was slightly normalized at day 35 PI. From this study, it is evident that neuronal damage occurs in the intestinal mucosa of N. seoulense-infected mice. However, the correlation between intestinal pathology, including the loop dilatation, and depressed GAP-43 expression remains to be elucidated
The Risk of Type 2 Diabetes Mellitus according to Changes in Obesity Status in Late Middle-Aged Adults: A Nationwide Cohort Study of Korea
Background Although obesity is a well-known risk factor of type 2 diabetes mellitus (T2DM), there is scant data on discriminating the contribution of previous obesity and recent weight gain on developing T2DM. Methods We analyzed the Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2015 where Korean residents underwent biennial health checkups. Participants were classified into four groups according to their obesity status (body mass index [BMI] ≥25 kg/m2) before and after turning 50 years old: maintaining normal (MN), becoming obese (BO), becoming normal (BN), and maintaining obese (MO). Cox proportional hazards regression model was used to estimate the risk of T2DM factoring in the covariates age, sex, BMI, presence of impaired fasting glucose or hypertension, family history of diabetes, and smoking status. Results A total of 118,438 participants (mean age, 52.5±1.1 years; men, 45.2%) were prospectively evaluated for incident T2DM. A total of 7,339 (6.2%) participants were diagnosed with T2DM during a follow-up period of 4.8±2.6 years. Incidence rates of T2DM per 1,000 person-year were 9.20 in MN, 14.81 in BO, 14.42 in BN, 21.38 in MO. After factoring in covariates, participants in the groups BN (adjusted hazard ratio [aHR], 1.15; 95% confidence interval [CI], 1.04 to 1.27) and MO (aHR, 1.14; 95% CI, 1.06 to 1.24) were at increased risk of developing T2DM compared to MN, whereas BO (hazard ratio, 1.06; 95% CI, 0.96 to 1.17) was not. Conclusion Having been obese before 50 years old increased the risk of developing T2DM in the future, but becoming obese after 50 did not. Therefore, it is important to maintain normal weight from early adulthood to prevent future metabolic perturbations
Development of a thorium coating on an aluminium substrate by using electrodeposition method and alpha spectroscopy
A thin coating of thorium on aluminium substrates with the areal density of
110 to 130 is developed over a circular area of 22 mm diameter by
using the electrodeposition method. An electrodeposition system is fabricated
to consist of three components; an anode made of a platinum mesh, a
cylindrical-shape vessel to contain the thorium solution, and a cathode in the
form of a circular aluminium plate. The aluminium plate is mounted
horizontally, and the platinum mesh is connected to an axial rod of an electric
motor, mounted vertically and normal to the plane of the aluminium. The
electrolyte solution is prepared by dissolving a known-weight thorium nitrate
powder in 0.8 M HNO3 and isopropanol. The system is operated either in constant
voltage (CV) or constant current (CC) mode. Under the electric field between
the anode and cathode, thorium ions were deposited on the aluminium substrate
mounted on the cathode. In the CV mode at 320, 360, and 400 V and in the CC
mode at 15 mA, thorium films were formed over a circular area of the aluminium
substrate. The areal density of thorium coating was measured by detecting
emitted alpha particles. The areal density of thorium varied from 80 to 130
by changing the deposition time from 10 to 60 min. The results
from the CV mode and CC mode are compared, and the radial dependence in the
measured areal density is discussed for different modes of the electric field.
The developed thorium coatings are to be used in the in-house development of
particle detectors, fast neutron converters, targets for thorium fission
experiments, and other purposes.Comment: 11 pages, 5 figures, 1 tabl
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