Earth horizon sensor is one of the fundamental instruments in satellite navigation system. This sensor is required to simulate satellite control system and to determine the satellite direction; hence, pyroelectric detectors are employed to achieve this target. In this paper, the physical model of pyroelectric detector and the mathematical model of an earth horizon sensor were presented to simulate a satellite. pyroelectric detectors are applied to calculate the step response and field of view (FOV), which are significant parameters to recognize the earth horizon. To improve the detection of objects in far distances of detector, FOV should be as small as possible. Furthermore, the effect of solar interference has been reduced by the use of narrow FOV for sensors. The evaluation of the device has been performed through the use of test system that allows sensor performance to be determined. The observed results show the optimal value of FOV has decreased to 50° using plastic pipes. The modeling results verified that the pyroelectric detectors are feasible to achieve functional requirements.

Misplacement of tracheal tube in the esophagus remains a significant cause of morbidity and mortality in anesthesia despite decades of effort aimed at prevention or (more importantly) detection of such an event. We have evaluated a cheap, simple and quick device (Esophageal detector Device; EDD) which relies mainly on the relation or otherwise of an evacuated elastic bulb applied to the supposed (tracheal) or (esophageal) tube.Identical tracheal tubes were passed into the trachea and esophagus of 100 patients, the left and right position in the mouth was chosen at random.The test was conducted by a second person, not present at intubations and unaware of the tube placed in the trachea. There were no false negatives (relation of elastic bulb applied to the tracheal tubes) probably due to bronchospasm early after induction of anesthesia. Correct deduction of the tracheal tube position was achieved in 98 patients using the device. We conclude that EDD could be a very sensitive (100%) and reliable method for detection of esophageal intubations however, it is recommended in further studies to test the tubes immediately after intubations (when bronchospasm is most probable) to find the exact specificity and accuracy of the device.

In the last decade, several studies have concluded that elevated concentrations of radon gas in soil or groundwater could be the sign of an imminent earthquake. It is believed that in case of sudden movement of rocks before earthquake, radon is released from the depth of ground and reached the surface. In this way, by measuring Radon concentration change, earthquake prediction is possible. In this study, for the purpose of the feasibility of using microstrip gas detector in monitoring Radon change, initially for the verification of the code, the range of radon alpha particles and its progeny in the air has been obtained in the standard condition, which is consistent with the experimental results. Then detector geometry has been simulated by MCNPX code and after examining the average of detector response to decay, the output code is calibrated considering the information about the radon changes in Jowshan hot spring. The results have shown that the detector response is comparable to the experimental data and can be used as an earthquake pre-indicator.

In this paper, a new algorithm for edge detection based on fuzzy concept is suggested. The proposed approach defines dynamic membership functions for different groups of pixels in a 3 by 3 neighborhood of the central pixel. Then, fuzzy distance and -cut theory are applied to detect the edge map by following a simple heuristic thresholding rule to produce a thin edge image. A large number of experiments are employed to con firm the robustness of the proposed algorithm. In the experiments different cases such as normal images, images corrupted by Gaussian noise, and uneven lightening images are involved. The results obtained are compared with some famous algorithms such as Canny and Sobel operators, a competitive fuzzy edge detector, and a statistical based edge detector. The visual and quantitative comparisons show the effectiveness of the proposed algorithm even for those images that were corrupted by strong noise.

The calibration procedure of silver activation detectors using a mono energetic neutron source with 5MeV beam energy at FRS of JAERI (Japan Atomic Energy Research Institute) is described in this paper. These detectors are fabricated for measuring fusion neutron burst emitted of z-pinch and plasma focus devices in ASRL (the Atomic Science Research Laboratory).

The behavior of an exponentially graded hybrid cylindrical shell subjected to an axisymmetric thermo-electro-mechanical loading placed in a constant magnetic field is investigated. The hybrid shell is consisted of a functionally graded host layer embedded with pyroelectric layers as sensor and/or actuator that can be imperfectly bonded to the inner and the outer surfaces of a shell. The shell is simply supported and could be rested on an elastic foundation. The material properties of the host layer are assumed to be exponentially graded in the radial direction. To solve governing differential equations, the Fourier series expansion method along the longitudinal direction and the differential quadrature method (DQM) across the thickness direction are used. Numerical examples are presented to discuss effective parameters influence on the response of the hybrid shell.

The aim of this paper is to design, manufacture and test the first triple RETGEM detector. Using resistive electrode in RETGEM detectors made them more robust against the electrical discharge with respect to THGEM detectors. However, even these robust detectors are not protected against electrical discharge at gains higher than 105. Studying the role of dimensions of the triple RETGEMS detectors and also the effect of pressure and gas mixtures on the gain level of detectors, we will show, the triple RETGEM detectors can reach the gains up to 106 without worrying about electrical discharge. We also compare the result of all tests for single and triple RETGEM detectors.

We have developed the effective algorithm for detecting digital binary phase-shift keyed signals. This algorithm requires a small number of arithmetic operations over the signal period. It can be relat ively easy implemented based on the modern programmable logic devices. It also provides high interference immunity by identifying signal presence when signal-to-noise ratio is much less that its working value in the receiving path. The introduced detector has int rinsic frequency selectivity and allows us to form the est imate of the noise level to realize the adaptive determination of decision threshold. In order to get confirmation of the detector operability and performance, we suggest the expressions for false alarm and missing probabilities. In addit ion, we have examine, both theoretically and experimentally, the influence of the detector parameters on its characterist ics.