Optical Fiber Multipoint Light Measurement System for the Investigation of Plant Cultivation Light Environment

Author(s):  
Takumi Kondo ◽  
Tadao Matsunaga ◽  
Ei Endo ◽  
Kotoku Ohmi ◽  
Sang-Seok Lee
Author(s):  
Hideaki Murayama ◽  
Kazuro Kageyama ◽  
Kohei Ohara ◽  
Kiyoshi Uzawa ◽  
Makoto Kanai ◽  
...  

Defects and damage in a structural joint can trigger a critical degradation or collapse of the structure. Among joints, welded joints have many uncertainties, such as remaining stress, initial defects, and heat-affected zone. Such uncertainties in a welded joint can also induce a strain fluctuation, when they are subjected to a load. Conversely, the strain fluctuation along the weld line may represent the presence of uncertainties in the welded joint. This means that monitoring strain distribution along the weld line can be good way to assess their integrity and improve reliability of the structure. We have developed a novel distributed strain measurement technique which can measure strain distributions along fiber Bragg gratings (FBG) in an optical fiber and has the high spatial resolution and we applied it to strain monitoring of a welded tubular joint. The spatial resolution o is less than 1 mm and it was confirmed by measurement simulations and experiments. Then, we measured the strain distributions along the weld line of the tubular joint of a steel pipe subjected to a tensile load by the developed measurement system. We could successfully measure the development of the strain distribution along the weld line, where the sharply fluctuating strain distributions resulting from some defects were observed. In this paper, we describe the measurement principle and performance of the optical fiber sensor, and then show the results of strain monitoring in the welded joint.


2019 ◽  
Vol 46 (9) ◽  
pp. 0904007
Author(s):  
王韵致 Yunzhi Wang ◽  
谢芳 Fang Xie ◽  
陈龙辉 Longhui Chen ◽  
徐海波 Haibo Xu ◽  
李明佳 Mingjia Li

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
A. Arifin ◽  
Nelly Agustina ◽  
Syamsir Dewang ◽  
Irfan Idris ◽  
Dahlang Tahir

This research discusses the polymer optical fiber sensor for respiratory measurements. The infrared LED that produces light will propagate along the polymer optical fiber which will be received by the phototransistor and the differential amplifier. The output voltage in the form of an analog signal will be converted to a digital signal by the Arduino Uno microcontroller and displayed on the computer. The polymer optical fiber sensor is installed on the corset using a variety of configuration (straight, sinusoidal, and spiral), placed in the abdomen, and a variety of positions (abdomen, chest, and back) using only a spiral configuration. While doing the inspiration, the stomach will be enlarged so that the optical fiber sensor will have strain. The strain will cause loss of power, the resulting light intensities received by the phototransistor are reduced, and the output voltage on the computer decreases. The result shows that the highest voltage amplitudes were in the spiral configuration placed in the abdominal position for slow respiration measurements with the highest range, sensitivity, and resolution which are 0.119 V, 0.238 V/s, and 0.004 s, respectively. The advantages of our work are emphasized on measurement system simplicity, low cost, easy fabrication, and handy operation and can be connected with the Arduino Uno microcontroller and computer.


2020 ◽  
Vol 31 (7) ◽  
pp. 075902 ◽  
Author(s):  
Hiroshi Murakami ◽  
Akio Katsuki ◽  
Takao Sajima ◽  
Kosuke Uchiyama ◽  
Ichiro Yoshida ◽  
...  

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