590 research outputs found
Estimation of a Multimass System Using the LWTLS and a Coefficient Diagram for Vibration-Controller Design
Vibration caused by mechanical resonance and time delay caused by signal detection and transmission degrade the control performance of a servo controller for a multimass mechanical system. A precise numerical model that represents resonance characteristics and time delay is necessary to design a desired control system. This paper presents an identification method using the iterative process of the linearized and weighted total least-squares method. The proposed method derives a transfer function without any prior knowledge of resonance characteristics and time delay. The order of the transfer function is determined with a coefficient diagram that shows coefficients of the denominator of the transfer function. Identification results with an experimental setup are shown to demonstrate the performance of the proposed method. A velocity servo controller with vibration-suppression control is designed with the transfer function, and control performance is verified with the experimental setup to validate the transfer function
DDPWM-based power conversion system using three to four phase matrix converter for stand-alone power system
This paper presents a novel stand-alone power system using a three to four phase matrix converter (MC) for use with renewable energy sources such as a micro hydro turbine or a tiny wind turbine with a permanent magnet synchronous generator (PMSG). MCs are able to convert AC power to AC power directly without using DC link capacitors, and AC to DC conversion is also possible because DC is considered to be a type of AC power. Here, two single phase AC outputs with constant frequency and two DC outputs for a battery storage system are described for a fluctuating voltage source. Direct duty ratio pulse width modulation (DDPWM) is used to achieve the desired output because it is easy to expand an ordinary three to three phase MC to produce a three to four phase MC. In addition, fictitious reference iterative tuning (FRIT) is used to design the controller gains. The validity of the proposed method is demonstrated using MATLAB/Simulink simulations
資源の動向に影響される部材企業の事業戦略に関する研究 : 透明電極部材関連企業に焦点を当てて
内容の要約広島大学(Hiroshima University)博士(学術)Doctor of Philosophydoctora
A Study on the Influence of Resource Trends on Material Manufacturers Business Strategies
内容の要約広島大学(Hiroshima University)博士(学術)Doctor of Philosophydoctora
Hemodynamic and autonomic response to acute hemorrhage in streptozotocin-induced diabetic rats
<p>Abstract</p> <p>Background</p> <p>The various autonomic control systems lead to characteristic changes in heart rate (HR) and blood pressure (BP) during acute hemorrhage. However, cardiovascular autonomic neuropathy due to diabetes mellitus may interfere with the normal compensation for hemorrhage.</p> <p>Materials and methods</p> <p>A controlled graded bleeding (6 - 36% loss of estimated total blood volume: ETBV) was performed in streptozotocin-induced diabetic rats (STZ rats) under a conscious state. Hemodynamic and autonomic responses to acute hemorrhage were examined using analysis of BP-HR variability. The effects of dextran treatment after hemorrhage were also examined.</p> <p>Results</p> <p>A significant reduction in mean arterial pressure began at 12% ETBV loss in STZ rats and 18% in the control rats, respectively. When blood loss reached 18% of TEBV, the decrease in HR was prominent in STD rats due to the activation of a parasympathetic drive, as indicated by the increase in high frequency (HF; 0.75~3.0 Hz) power in HR variability, while in the control rats this response was not observed. The administration of dextran prevented the activation of the parasympathetic drive in STZ rats during hemorrhaging. In the control rats, the dextran treatment sustained the initial increase in HR with reduced HF power in HR variability.</p> <p>Conclusion</p> <p>STZ rats showed different hemodynamic and autonomic responses to acute hemorrhage from the control rats. STZ rats were prone to develop bradycardiac hypotension characterized by marked parasympathetic activation during hemorrhaging. This finding suggests enhancement of the Bezold-Jarisch reflex in STZ rats. Dextran treatment to maintain a normovolemic hemorrhage state inhibits this reflex.</p
資源の動向に影響される部材企業の事業戦略に関する研究 : 透明電極部材関連企業に焦点を当てて
内容の要約博士(学術)博士(学術)広島大
Recommended from our members
Study in User Preferred Pen Gestures for Controlling a Virtual Character
Controlling a virtual character with a pen input device is difficult. Pen input
devices require freeform gestures and users are not confined to particular mapping of a
key or a button that is exactly repeatable. This is a problem since an intuitive motion
gesture for one user might not be intuitive for another user. In this paper, we explore user
preferred input gestures for character control through user experiments. Most previous
pen input gesture sets are based on the preference of the developer. Our goal is to try to
find common pen gesture features for common commands through user experiments. For
our experiment, we have chosen navigational motions that are common for controlling a
character in a virtual world. The users were asked to make gestures for a set of
navigational motions according to their intuition. We then analyzed the gesture data and
outlined some gesture design guidelines as well as compared the resulting gestures to
those used in existing applications that use pen devices for character control
Premedication with midazolam in intellectually disabled dental patients: intramuscular or oral administration? A retrospective study
Background: The use of midazolam for dental care in patients with intellectual disability is poorly documented.
The purpose of this study was to determine which method of premedication is more effective for these patients,
0.15 mg/kg of intramuscular midazolam or 0.3 mg/kg of oral midazolam.
Material and Methods: This study was designed and implemented as a non-randomized retrospective study. The
study population was composed of patients with intellectual disability who required dental treatment under ambulatory general anesthesia from August 2009 through April 2013. Patients were administered 0.15 mg/kg of
midazolam intramuscularly (Group IM) or 0.3 mg/kg orally (Group PO). The predictor variable was the method
of midazolam administration. The outcome variables measured were Observer’s Assessment of Alertness/ Sedation (OAA/S) Scale scores, the level of cooperation when entering the operation room and for venous cannulation,
post-anesthetic agitation and recovery time.
Results: Midazolam was administered intramuscularly in 23 patients and orally in 21 patients. More patients
were successfully sedated with no resistance behavior during venous cannulation in Group PO than in Group IM
(
p
=0.034). There were no differences in demographic data and other variables between the groups.
Conclusions: The results of this study suggest that oral premedication with 0.3 mg/kg of midazolam is more effective than 0.15 mg/kg of midazolam administered intramuscularly, in terms of patient resistance to venous cannulation. If both oral and intramuscular routes of midazolam are acceptable in intellectually disabled patients, the
oral route is recommended
Scanning Electron Microscopic Observations on the Intracellular Structures of the Ciliated Tracheal Epithelium?Especially on the Morphological Differences between Conventional Rats and Specific Pathogen-Free Rats
The three-dimensional architecture of the intracellular structures of the tracheal ciliated epithelium was studied by scanning electron microscopy, paying particular attention to the morphological difference between conventional rats and specific pathogen-free (SPF) rats. The surface of the trachea was densely covered with cilia in conventional rats, but less in SPF rats. The smooth endoplasmic reticulum (ER) formed a three-dimensional tubular meshwork under the basal bodies in both rats. In conventional rats, the Golgi apparatus was highly developed and many Golgi vesicles were attached to the lateral margin of the Golgi cisternae. In addition, the rough ER spread around the nucleus. In the SPF rats, however, the Golgi appatatus was not so highly developed and the rough ER was scarcely visible. The development of the Golgi apparatus and rough ER observed in the conventional rats indicate the active protein synthesis for the formation of the cilia which plays an important role in antimicrobial defense mechanisms
Power mapping characteristic of double stator permanent magnet generator for electrical harvesting machine
The Malaysia's average of oil palm production have been increasing every year since last two decades. This is due to the increase global demands. Therefore, it is an urgent need to improve the harvesting productivity in the field. For such reasons, a harvesting machine had been developed to overcome this problem. This harvesting machine consists of DC motor and powered by electrical generator. Due to limitation of space and weight, Double Stator Permanent Magnet Generator (DSPMG) topology is being used. DSPMG has an advantage in producing high power density compared to conventional generator due to its large coil area. Sudden changes of current can be seen as the load changes when the harvester operates. Obviously, the generator performance needs to be studied. Therefore, this paper discusses on the performance of DSPMG by evaluating the power mapping characteristic. From the power mapping characteristic, the overall view of generator performance can be presented. The DSPMG shows that the highest output power (180W) can be achieved at load impedance of 10 Ω
- …