Intradialytic hypotension (IDH) is a very common complication during hemodialysis. IDH may lead to nausea, vomiting, or anxiety. In some severe cases, it may cause shock or death. Each hemodialysis treatment generally lasts for four to six hours and must be repeated two or three times a week. Currently, the hemodialysis procedure may lead to dangerously low blood pressure when blood pressure is not frequently assessed by medical staff. Therefore, the purpose of this work is to use the technologies of wireless sensor networks (WSN), global systems for mobile communications (GSM), and a MySQL database to develop a PC-based gateway and an automatic monitoring system to collect physiological data during hemodialysis and continuously monitor the IDH status of patients. The clinical definition of IDH during hemodialysis is a decrease in the systolic pressure of at least 20 mmHg and a decrease in the mean arterial pressure (MAP) of at least 10 mmHg. Our system uses a threshold-based algorithm to monitor and record the systolic and mean arterial blood pressure readings. The GSM module is utilized to send medical staff a warning message, and the message is displayed on the monitor if the readings reach a critical point. The experimental results show that this monitoring system is highly reliable.
In this work, a quantitative study for glucose concentration determination was conducted using ATR-THz spectroscopy. Glucose solutions with different concentrations were prepared and their absorbance spectra between wavenumber 19.285 cm-1 and 451.261 cm-1 were acquired using a terahertz-based Fourier transform spectrometer. The spectra of glucose solutions in different concentrations were compared and discussed. The results showed that increasing glucose concentration caused decreasing absorbance. Calibration models for glucose determination were developed using partial least squares (PLS) regression for original and pre-processing spectra. The calibration model using Savitzky-Golay second derivative spectra gave satisfactory results. The use of ATR-THz spectroscopy combined with an appropriate chemometric method has potential for a rapid determination of glucose concentrations in aqueous solution.
We developed an intuitive tractor navigation system using augmented reality (AR) by superimposing a computer-generated virtual three-dimensional (3D) image on a camera image. The 3D image was generated using the tractor position and direction determined by two real-time kinematic global positioning systems and an inertial measurement unit. The positioning accuracy of the AR navigation system was examined experimentally by changing the roll, pitch, and yaw angles of a tractor at rest on an actual field. The positioning errors in the world coordinate system were less than 3 cm within 3 m from the front of the tractor, and less than 3 pixels in the image coordinate system. The refresh frequency of the AR image was 30 Hz and the time taken from image capturing to displaying was within 10 ms.
The flight of separated straws is thought to affect the cleaning wind of a combine harvester. To comprehend the turbulent flow characteristics of the cleaning wind and its passage through the grains, the cleaning wind velocity is measured by particle image velocimetry and laser Doppler velocimetry. The flow of the cleaning wind is blocked by the grains, and therefore the distribution of wind velocity changes. It is found that the energy loss of the cleaning wind is not a result of turbulent flow. The wall friction and the pressure change observed as a result of the shape and the friction loss in the grains are the main considerations while calculating the energy loss of the cleaning wind in combine harvester.
A method is proposed for soil improvement of salt-affected soils to till down to about 600 mm in depth by a special plough. The goal is to cut off the capillary rise of the groundwater by creating a coarse layer of tilled subsoil. Earlier, a plough configuration to produce soil clods with the proper size in the subsoil was determined in an indoor soil bin. In this paper, we designed and tested prototypical plough bodies in field experiments. A plough blade length less than 130 mm produced large soil clods and a blade length more than 130 mm generated small ones. With any length, deeper operating depth caused larger soil clods to form. The proper specifications of the third and fourth plough bodies of the special plough are as follows: the plough blade length is 130 mm, the operating width is 300 mm, the operating depth is 200 mm and the cutting angle is 20°.
It is necessary to develop a design theory of the knife driving system of combine harvesters in order to derive the control parameters of the balance weights used for vibration reduction. A collision vibration model of the knife driving system that is equipped with a slider-crank mechanism was constructed in order to examine the influence of the interspace that arises at the joint of the drive knife and the end of the link arm. The simulation result revealed that the harmonic frequency components varied with an increase in the width of the interspace although the highest harmonic frequency in the simulation without the interspace was three times the crank wheel rotation frequency. However, the vibration reduction by the balance weight was not dependent on the width of the interspace.