Journal articles on the topic 'Low background sensor'
To see the other types of publications on this topic, follow the link: Low background sensor.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Low background sensor.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Honeycutt, Wesley T., M. Tyler Ley, and Nicholas F. Materer. "Precision and Limits of Detection for Selected Commercially Available, Low-Cost Carbon Dioxide and Methane Gas Sensors." Sensors 19, no. 14 (July 18, 2019): 3157. http://dx.doi.org/10.3390/s19143157.
Full textAbstract:
The performance of a sensor platform for environmental or industrial monitoring is sensitive to the cost and performance of the individual sensor elements. Thus, the detection limits, accuracy, and precision of commercially available, low-cost carbon dioxide and methane gas concentration sensors were evaluated by precise measurements at known gas concentrations. Sensors were selected based on market availability, cost, power consumption, detection range, and accuracy. A specially constructed gas mixing chamber, coupled to a precision bench-top analyzer, was used to characterize each sensor during a controlled exposure to known gas concentrations. For environmental monitoring, the selected carbon dioxide sensors were characterized around 400 ppm. For methane, the sensor response was first monitored at 0 ppm, close to the typical environmental background. The selected sensors were then evaluated at gas concentrations of several thousand ppm. The determined detection limits accuracy, and precision provides a set of matrices that can be used to evaluate and select sensors for integration into a sensor platform for specific applications.
2
Ju, Youngkwan, and Hyung Jin Mun. "The Research on Security Technology for Low-Performance Iot Sensor Node." International Journal of Engineering & Technology 7, no. 3.34 (September 1, 2018): 594. http://dx.doi.org/10.14419/ijet.v7i3.34.19389.
Full textAbstract:
Background/Objectives: IoT developmental background: IoT, which is the key technology in the fourth industrial revolution, utilizes the Internet. Particularly, the growth of convergence products that utilize it has been constant with the demands of IoT services using the network of the Internet.Methods/Statistical analysis: IoT network consists of products equipped with various sensors to communicate; sensor nodes are made up of low volume memory, low performance CPU, and battery when they are used in the network. There has been the demand of secure transmission of information measured by a sensor node to the IoT platform. We conduct a study on how we can improve security in the IoT environment.Findings: Generally, sensor nodes are applied with basic security provided by IoT communication protocol rather than their own encryption. Therefore, sensor nodes are vulnerable in terms of security and the IoT platform that utilizes information collected by them would process distorted information.In order to draw a strategy to prevent security breach, we analyze security threat and the type of attacks.Improvements/Applications: We suggest a countermeasure to deal with security threat of sensor nodes and situations in which sensor nodes are vulnerable in IoT environment. To secure integrity of communication and transaction between a sensor node and an IoT platform in the future, the application of block chain technology into the IoT environment is necessary.
3
Rivilla, Iván, Borja Aparicio, Juan M. Bueno, David Casanova, Claire Tonnelé, Zoraida Freixa, Pablo Herrero, et al. "Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments." Nature 583, no. 7814 (June 22, 2020): 48–54. http://dx.doi.org/10.1038/s41586-020-2431-5.
Full text
4
Wang, Xiaoqing, Zhipeng Liu, Fang Qian, and Weijiang He. "A bezoimidazole-based highly selective and low-background fluorescent sensor for Zn2+." Inorganic Chemistry Communications 15 (January 2012): 176–79. http://dx.doi.org/10.1016/j.inoche.2011.10.018.
Full text
5
Sumanto, Joko. "PEMBACAAN NOMOR SAMPEL DALAM REFURBISHING ALAT LOW BACKGROUND COUNTER-LBC TENNELEC TYPE LB5100 SERIES II." Jurnal Forum Nuklir 3, no. 2 (November 1, 2009): 131. http://dx.doi.org/10.17146/jfn.2009.3.2.3298.
Full textAbstract:
PEMBACAAN NOMOR SAMPLE DALAM REFURBISHING ALAT LBC TENNELEC TYPE LB5100 SERIES II. Telah dirancang dan dibuat interface pembacaan nomor sample secara otomatis dengan komputer melalui komunikasi serial USB dalam rangka refurbishing alat LBC TENNELEC type LB5100. Refurbishing dilakukan dengan cara memanfaatkan bagian mekanik dari instrumen dan mengganti bagian elektronik yang kadaluwarsa dengan berbasis komputer pribadi-PC. Pada alat ini, sample yang diukur cukup banyak sehingga perlu dilakukan secara otomatis. Setiap sample telah ditandai dengan lobang-lobang yang disusun tertentu yang mengindikasikan nomor sample, group, dan send stack reader. Pada bagian mekanik diletakkan beberapa sensor photo transistor sesuai kedudukan sample. Sensor dihubungkan dengan jalur data dan dikirim ke komputer melalui komunikasi serial USB. Alat tersebut mampu mengukur 150 sampel dan 10 group. Hasil pengujian telah sesuai yang diharapkan.
6
Scholz, Michael, Sudharshana Venkataraman Rmasubramanian, Andreas Blank, Sven Kreitlein, and Jörg Franke. "E|Flow II - Infrastructural Sensor Concepts to Digitize the Workspace for Sustainable and Resource Efficient Intralogistics." Applied Mechanics and Materials 871 (October 2017): 97–102. http://dx.doi.org/10.4028/www.scientific.net/amm.871.97.
Full textAbstract:
Nowadays material flow in factories is realized by different concepts of transport. Each of those specific conveyers has pros and cons due to its concept. In general, the state of art of transport systems have a low flexibility of the path planning and are not suitable for dynamic transport requirements, wherefore they are designed for a specific application. Generally, the common systems cover a specific task of transportation and can fulfill a predefined maximum amount of transportation orders. Therefore, it is necessary that the next generations of production lines, especially the intralogistics transportation systems, have to be designed more adaptable and flexible. The object of the research in this paper is a cyber-physical material flow system with flexible, autonomous and collaborative vehicles combined with centralized sensors to digitize the workspace. These sensors are a combination of commonly used USB cameras with a single board computer to realize an embedded senor system. The whole device is mounted to the ceiling of a factory to digitize the workspace. The single board computer proceed the scenario below the camera and provides the results of the code via WLAN to a central device on the one side, on the other side directly to the autonomous vehicles within the scenario. The algorithm separates moving obstacle by calculating an adaptive background picture. The obstacles are marked with a rotatable rectangle which coordinates are submitted to the vehicles. The adaptive background picture is provided by service to the central device, where the background pictures of all sensors are merged together. Here, a morphologic algorithm separates static obstacles and marks the space where the vehicles can operate. This approach leads to a performant and low cost sensor architecture for an infrastructural sensor concept to realize a digital twin of a workspace.
7
Bousiotis, Dimitrios, Ajit Singh, Molly Haugen, David C. S. Beddows, Sebastián Diez, Killian L. Murphy, Pete M. Edwards, Adam Boies, Roy M. Harrison, and Francis D. Pope. "Assessing the sources of particles at an urban background site using both regulatory instruments and low-cost sensors – a comparative study." Atmospheric Measurement Techniques 14, no. 6 (June 7, 2021): 4139–55. http://dx.doi.org/10.5194/amt-14-4139-2021.
Full textAbstract:
Abstract. Measurement and source apportionment of atmospheric pollutants are crucial for the assessment of air quality and the implementation of policies for their improvement. In most cases, such measurements use expensive regulatory-grade instruments, which makes it difficult to achieve wide spatial coverage. Low-cost sensors may provide a more affordable alternative, but their capability and reliability in separating distinct sources of particles have not been tested extensively yet. The present study examines the ability of a low-cost optical particle counter (OPC) to identify the sources of particles and conditions that affect particle concentrations at an urban background site in Birmingham, UK. To help evaluate the results, the same analysis is performed on data from a regulatory-grade instrument (SMPS, scanning mobility particle sizer) and compared to the outcomes from the OPC analysis. The analysis of the low-cost sensor data manages to separate periods and atmospheric conditions according to the level of pollution at the site. It also successfully identifies a number of sources for the observed particles, which were also identified using the regulatory-grade instruments. The low-cost sensor, due to the particle size range measured (0.35 to 40 µm), performed rather well in differentiating sources of particles with sizes greater than 1 µm, though its ability to distinguish their diurnal variation, as well as to separate sources of smaller particles, at the site was limited. The current level of source identification demonstrated makes the technique useful for background site studies, where larger particles with smaller temporal variations are of significant importance. This study highlights the current capability of low-cost sensors in source identification and differentiation using clustering approaches. Future directions towards particulate matter source apportionment using low-cost OPCs are highlighted.
8
Fernandez, Marco, Kathy Burns, Beverly Calhoun, Saramma George, Beverly Martin, and Chris Weaver. "Evaluation of a New Pulse Oximeter Sensor." American Journal of Critical Care 16, no. 2 (March 1, 2007): 146–52. http://dx.doi.org/10.4037/ajcc2007.16.2.146.
Full textAbstract:
• Background A new forehead noninvasive oxygen saturation sensor may improve signal quality in patients with low cardiac index. • Objectives To examine agreement between oxygen saturation values obtained by using digit-based and forehead pulse oximeters with arterial oxygen saturation in patients with low cardiac index. • MethodsA method-comparison study was used to examine the agreement between 2 different pulse oximeters and arterial oxygen saturation in patients with low cardiac index. Readings were obtained from a finger and a forehead sensor and by analysis of a blood sample. Bias, precision, and root mean square differences were calculated for the digit and forehead sensors. Differences in bias and precision between the 2 noninvasive devices were evaluated with a t test (level of significance P<.05). • Results Nineteen patients with low cardiac index (calculated as cardiac output in liters per minute divided by body surface area in square meters; mean 1.98, SD 0.34) were studied for a total of 54 sampling periods. Mean (SD) oxygen saturations were 97% (2.4) for blood samples, 96% (3.2) for the finger sensor, and 97% (2.8) for the forehead sensor. By Bland Altman analysis, bias ± precision was −1.16 ± 1.62% for the digit sensor and −0.36 ± 1.74% for the forehead sensor; root mean square differences were 1.93% and 1.70%, respectively. Bias and precision differed significantly between the 2 devices; the forehead sensor differed less from the blood sample. • Conclusions In patients with low cardiac index, the forehead sensor was better than the digit sensor for pulse oximetry.
9
Fu, Hao, ChinYin Chen, Chongchong Wang, MinChiang Chao, Qiang Zhou, Guilin Yang, and Guozhi Wang. "Quartz crystal based sensor head design and analysis for robot torque sensor application." Cobot 1 (April 26, 2022): 11. http://dx.doi.org/10.12688/cobot.17474.1.
Full textAbstract:
Background: In recent years, with the gradual development of robot human-computer interaction, robots need to meet the precise control of more complex motion. Torque sensors play an important role. The traditional strain gauge sensor uses a metal strain gauge as the sensitive element, which means that the sensor has a slow response, low resolution and can easily be affected by external signal noise. Aiming at these deficiencies of strain gauge sensors, a sensor with cutting quartz square sheet as the sensor head is proposed. Methods: In order to study the application of quartz square sensing head in the sensor, firstly, COMSOL (5.6) simulation modeling is used to obtain the stress relationship between square quartz sheet and circular quartz sheet. Then the calculation formula of the force frequency coefficient of the circular quartz sheet is modified to obtain the calculation formula of the force frequency coefficient of the square quartz sheet, and the feasibility of the formula is verified by practical experiments. Next, the theoretical simulation and experimental research on the buckling limit force of quartz wafer are carried out, and the formula of buckling limit force in the process of quartz wafer installation is modified. Finally, the designed sensitive head is installed on the elastomer structure for verification. The frequency signal is collected by SGS-THOMSON Microelectronics 32 with a sampling rate of 1000Hz. Results: The main performances of the sensor are range 150nm, sensitivity 350Hz / nm, linearity 98.14%, hysteresis 0.51%, repeatability 98.44%, resolution 0.02%. Conclusions: As the sensitive unit of the torque sensor, the designed quartz wafer can obtain high response time and high resolution, solve the problems of low resolution and slow response time of the traditional strain gauge torque sensor, and reduce the use cost of the sensor.
10
Fu, Hao, ChinYin Chen, Chongchong Wang, MinChiang Chao, Qiang Zhou, Guilin Yang, and Guozhi Wang. "Quartz crystal based sensor head design and analysis for robot torque sensor application." Cobot 1 (April 26, 2022): 11. http://dx.doi.org/10.12688/cobot.17474.1.
Full textAbstract:
Background: In recent years, with the gradual development of robot human-computer interaction, robots need to meet the precise control of more complex motion. Torque sensors play an important role. The traditional strain gauge sensor uses a metal strain gauge as the sensitive element, which means that the sensor has a slow response, low resolution and can easily be affected by external signal noise. Aiming at these deficiencies of strain gauge sensors, a sensor with cutting quartz square sheet as the sensor head is proposed. Methods: In order to study the application of quartz square sensing head in the sensor, firstly, COMSOL (5.6) simulation modeling is used to obtain the stress relationship between square quartz sheet and circular quartz sheet. Then the calculation formula of the force frequency coefficient of the circular quartz sheet is modified to obtain the calculation formula of the force frequency coefficient of the square quartz sheet, and the feasibility of the formula is verified by practical experiments. Next, the theoretical simulation and experimental research on the buckling limit force of quartz wafer are carried out, and the formula of buckling limit force in the process of quartz wafer installation is modified. Finally, the designed sensitive head is installed on the elastomer structure for verification. The frequency signal is collected by SGS-THOMSON Microelectronics 32 with a sampling rate of 1000Hz. Results: The main performances of the sensor are range 150nm, sensitivity 350Hz / nm, linearity 98.14%, hysteresis 0.51%, repeatability 98.44%, resolution 0.02%. Conclusions: As the sensitive unit of the torque sensor, the designed quartz wafer can obtain high response time and high resolution, solve the problems of low resolution and slow response time of the traditional strain gauge torque sensor, and reduce the use cost of the sensor.
11
Wu, Jianqing, Hao Xu, Yuan Sun, Jianying Zheng, and Rui Yue. "Automatic Background Filtering Method for Roadside LiDAR Data." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 45 (June 17, 2018): 106–14. http://dx.doi.org/10.1177/0361198118775841.
Full textAbstract:
The high-resolution micro traffic data (HRMTD) of all roadway users is important for serving the connected-vehicle system in mixed traffic situations. The roadside LiDAR sensor gives a solution to providing HRMTD from real-time 3D point clouds of its scanned objects. Background filtering is the preprocessing step to obtain the HRMTD of different roadway users from roadside LiDAR data. It can significantly reduce the data processing time and improve the vehicle/pedestrian identification accuracy. An algorithm is proposed in this paper, based on the spatial distribution of laser points, which filters both static and moving background efficiently. Various thresholds of point density are applied in this algorithm to exclude background at different distances from the roadside sensor. The case study shows that the algorithm can filter background LiDAR points in different situations (different road geometries, different traffic demands, day/night time, different speed limits). Vehicle and pedestrian shape can be retained well after background filtering. The low computational load guarantees this method can be applied for real-time data processing such as vehicle monitoring and pedestrian tracking.
12
Agashe, Geeta S., Joseph Coakley, and Paul D. Mannheimer. "Forehead Pulse Oximetry." Anesthesiology 105, no. 6 (December 1, 2006): 1111–16. http://dx.doi.org/10.1097/00000542-200612000-00010.
Full textAbstract:
Background This study investigated whether a tensioning headband that applies up to 20 mmHg pressure over a forehead pulse oximetry sensor could improve arterial hemoglobin oxygen saturation reading accuracy in presence of venous pooling and pulsations at the forehead site. Methods Healthy volunteers were studied breathing room air in supine and various levels of negative incline (Trendelenburg position) using the forehead sensor with the headband adjusted to its maximum and minimum recommended pressure limits. Saturation readings obtained from the forehead sensor with the subjects supine and the headband in place were used as a baseline to compare the effects of negative incline on reading accuracy when using and not using the headband. Occurrences of false low-saturation readings detected by forehead sensors were compared with those from digit sensors. Results No difference was observed between saturation readings obtained from the forehead sensor in supine and negative incline positions when the headband was applied. Forehead sensor readings obtained while subjects were inclined and the headband was not used were significantly lower (P < 0.05) than the supine readings. There was no statistically significant difference between the digit and forehead sensor in reporting false low-saturation readings when the headband was applied, regardless of body incline. Conclusions Application of up to 20 mmHg pressure on the forehead pulse oximetry sensor using an elastic tensioning headband significantly reduced reading errors and provided consistent performance when subjects were placed between supine and up to 15 degrees head-down incline (Trendelenburg position).
13
Yin, Yang, Yang Liu, Shuai Chen, and Quanshun Yang. "UAV Target Detection under Complex Sky Background." Journal of Autonomous Intelligence 5, no. 2 (October 22, 2022): 1. http://dx.doi.org/10.32629/jai.v5i2.514.
Full textAbstract:
<p class="15">At present, unmanned aerial vehicles (UAVs) are widely used in various fields, and the management of UAVs is very important to solve the problems in the field of low-altitude safety. Due to the low flying height, small radar cross section, and inconspicuous characteristic signals of UAVs, the detection of UAVs based on video frames taken by fixed cameras cannot meet the existing requirements in terms of tracking speed and recognition accuracy. This paper proposes a multi-sensor fusion model. Firstly, the UAV target signal is improved by spatial filtering and improved Sobel operator edge detection algorithm, and then Gaussian filter is used to denoise, and finally the UAV small target is extracted based on the maximum inter-class variance method threshold segmentation algorithm. Experimental results show that this method can effectively enhance the UAV target signal in a complex environment, and the threshold segmentation method also has good adaptability, and can effectively screen UAVs under a complex sky background.</p>
14
Schmitt, Katrin, Mara Sendelbach, Christian Weber, Jürgen Wöllenstein, and Thomas Strahl. "Resonant photoacoustic cells for laser-based methane detection." Journal of Sensors and Sensor Systems 12, no. 1 (January 25, 2023): 37–44. http://dx.doi.org/10.5194/jsss-12-37-2023.
Full textAbstract:
Abstract. Against the background of the steady increase in greenhouse gases in the atmosphere, a fast and inexpensive method for detecting methane is required. This applies to the direct measurement of the background concentration of methane in the atmosphere and also to the detection of leaks in natural gas pipelines. Photoacoustic (PA) sensors offer the possibility of highly sensitive gas detection and cost-effective design at the same time. In this work, we investigated a photoacoustic sensor for methane in low concentrations, focusing on a special cell design, the so-called T-cell. Different cylinder geometries of six T-cells and the influence on the sensor performance were examined. An interband cascade laser (ICL) with a central wavelength of 3270 nm was used for excitation and a micro-electromechanical systems (MEMS) microphone as detector. The detection limits achieved were below the methane background concentration in air of 1.8 ppm.
15
Kim, Byeong, Danish Khan, Ciril Bohak, Wonju Choi, Hyun Lee, and Min Kim. "V-RBNN Based Small Drone Detection in Augmented Datasets for 3D LADAR System." Sensors 18, no. 11 (November 8, 2018): 3825. http://dx.doi.org/10.3390/s18113825.
Full textAbstract:
A common countermeasure to detect threatening drones is the electro-optical infrared (EO/IR) system. However, its performance is drastically reduced in conditions of complex background, saturation and light reflection. 3D laser sensor LiDAR is used to overcome the problems of 2D sensors like EO/IR, but it is not enough to detect small drones at a very long distance because of low laser energy and resolution. To solve this problem, A 3D LADAR sensor is under development. In this work, we study the detection methodology adequate to the LADAR sensor which can detect small drones at up to 2 km. First, a data augmentation method is proposed to generate a virtual target considering the laser beam and scanning characteristics, and to augment it with the actual LADAR sensor data for various kinds of tests before full hardware system developed. Second, a detection algorithm is proposed to detect drones using voxel-based background subtraction and variable radially bounded nearest neighbor (V-RBNN) method. The results show that 0.2 m L2 distance and 60% expected average overlap (EAO) indexes are satisfied for the required specification to detect 0.3 m size of small drones.
16
Chang, Jiang, and Yingying Tan. "Application of GIS Sensor Technology in Digital Management of Urban Gardens under the Background of Big Data." Journal of Sensors 2022 (June 26, 2022): 1–9. http://dx.doi.org/10.1155/2022/6700254.
Full textAbstract:
Since the reform and opening up, China’s urbanization level has been continuously improved, and the national demand for urban greening is also increasing. However, at present, there are many problems in domestic urban gardens, such as low management quality and high management cost, which have a certain negative impact on urban development and residents’ life. In this study, a digital management system of urban garden plant growth state based on sensor client/server structure, GIS (geographic information system) sensor technology and big data technology are designed, and its practicability is tested. The test results show that 52.90% and 40.70% of the people have positive comments on the satisfaction of the system client and the sensor comprehensive application value of the system based on WebGIS sensor technology, respectively. The former is 12.2 percentage points higher than the latter, and the server response speed and CPU (central processing unit) resource consumption of the former are also better. In addition, the robustness of the former is not significantly different from that of the latter. The data show that the digital sensor management system for the growth state of urban garden plants designed in this paper has complete and normal functions and good user experience.
17
Karimi-Maleh, Hassan, Fatemeh Karimi, Morteza Rezapour, Majede Bijad, Mohammad Farsi, Aliasghar Beheshti, and Seyed-Ahmad Shahidi. "Carbon Paste Modified Electrode as Powerful Sensor Approach Determination of Food Contaminants, Drug Ingredients, and Environmental Pollutants: A Review." Current Analytical Chemistry 15, no. 4 (July 3, 2019): 410–22. http://dx.doi.org/10.2174/1573411014666181026100037.
Full textAbstract:
Background: Application of electrochemical sensors for analysis of food, biological and water polluting compounds helps to speed up their analysis in the real samples. Electrochemical sensors with low cost, fast response and portable ability are a better choice compared to traditional methods for analysis of electro-active compounds such as HPLC. Therefore, in recent years, many analytical scientists have suggested this type of analytical method for analysis of food, biological compounds and water pollutants. Objective: Due to low cost, easy modification and low non-faradic current, the carbon paste electrode is a suitable choice as a working electrode in the electrochemical and especially voltammetric analysis. On the other hand, modification of carbon paste electrode can improve the quality of the sensor for the analysis of electroactive compounds at nanomolar level.
18
Liu, Yun-Long, Hai-Ping Wu, Qiang Zhou, Qin-Xin Song, Jian-Zhong Rui, Xiao-Xiang Guan, Guo-Hua Zhou, and Bing-Jie Zou. "Controllable extension of hairpin-structured flaps to allow low-background cascade invasive reaction for a sensitive DNA logic sensor for mutation detection." Chemical Science 9, no. 6 (2018): 1666–73. http://dx.doi.org/10.1039/c7sc04210h.
Full text
19
Sauerwald, Tilman, Tobias Baur, Martin Leidinger, Wolfhard Reimringer, Laurent Spinelle, Michel Gerboles, Gertjan Kok, and Andreas Schütze. "Highly sensitive benzene detection with metal oxide semiconductor gas sensors – an inter-laboratory comparison." Journal of Sensors and Sensor Systems 7, no. 1 (April 5, 2018): 235–43. http://dx.doi.org/10.5194/jsss-7-235-2018.
Full textAbstract:
Abstract. For detection of benzene, a gas sensor system with metal oxide semiconductor (MOS) gas sensors using temperature-cycled operation (TCO) is presented. The system has been tested in two different laboratories at the concentration range from 0.5 up to 10 ppb. The system is equipped with three gas sensors and advanced temperature control and read-out electronics for the extraction of features from the TCO signals. A sensor model is used to describe the sensor response in dependence on the gas concentration. It is based on a linear differential surface reduction (DSR) at a low temperature phase, which is linked to an exponential growth of the sensor conductance. To compensate for cross interference to other gases, the DSR is measured at three different temperatures (200, 250, 300 ∘C) and the calculated features are put into a multilinear regression (partial least square regression – PLSR) for the quantification of benzene at both laboratories. In the tests with the first set-up, benzene was supplied in defined gas profiles in a continuous gas flow with variation of humidity and various interferents, e.g. toluene and carbon monoxide (CO). Depending on the gas background and interferents, the quantification accuracy is between ±0.2 and ±2 ppb. The second gas mixing system is based on a circulation of the carrier gas stream in a closed-loop control for the benzene concentration and other test gases based on continuously available reference measurements for benzene and other organic and inorganic compounds. In this system, a similar accuracy was achieved for low background contaminations and constant humidity; the benzene level could be quantified with an error of less than 0.5 ppb. The transfer of regression models for one laboratory to the other has been tested successfully.
20
Frederickson, Louise Bøge, Shanon Lim, Hugo Savill Russell, Szymon Kwiatkowski, James Bonomaully, Johan Albrecht Schmidt, Ole Hertel, Ian Mudway, Benjamin Barratt, and Matthew Stanley Johnson. "Monitoring Excess Exposure to Air Pollution for Professional Drivers in London Using Low-Cost Sensors." Atmosphere 11, no. 7 (July 15, 2020): 749. http://dx.doi.org/10.3390/atmos11070749.
Full textAbstract:
In this pilot study, low-cost air pollution sensor nodes were fitted in waste removal trucks, hospital vans and taxis to record drivers’ exposure to air pollution in Central London. Particulate matter (PM 2.5 and PM 10 ), CO 2 , NO 2 , temperature and humidity were recorded in real-time with nodes containing low-cost sensors, an electrochemical gas sensor for NO 2 , an optical particle counter for PM 2.5 and PM 10 and a non-dispersive infrared (NDIR) sensor for CO 2 , temperature and relative humidity. An intervention using a pollution filter to trap PM and NO 2 was also evaluated. The measurements were compared with urban background and roadside monitoring stations at Honor Oak Park and Marylebone Road, respectively. The vehicle records show PM and NO 2 concentrations similar to Marylebone Road and a higher NO 2 -to-PM ratio than at Honor Oak Park. Drivers are exposed to elevated pollution levels relative to Honor Oak Park: 1.72 μ g m − 3 , 1.92 μ g m − 3 and 58.38 ppb for PM 2.5 , PM 10 , and NO 2 , respectively. The CO 2 levels ranged from 410 to over 4000 ppm. There is a significant difference in average concentrations of PM 2.5 and PM 10 between the vehicle types and a non-significant difference in the average concentrations measured with and without the pollution filter within the sectors. In conclusion, drivers face elevated air pollution exposure as part of their jobs.
21
Bousiotis, Dimitrios, David C. S. Beddows, Ajit Singh, Molly Haugen, Sebastián Diez, Pete M. Edwards, Adam Boies, Roy M. Harrison, and Francis D. Pope. "A study on the performance of low-cost sensors for source apportionment at an urban background site." Atmospheric Measurement Techniques 15, no. 13 (July 8, 2022): 4047–61. http://dx.doi.org/10.5194/amt-15-4047-2022.
Full textAbstract:
Abstract. Knowledge of air pollution sources is important in policymaking and air pollution mitigation. Until recently, source apportion analyses were limited and only possible with the use of expensive regulatory-grade instruments. In the present study we applied a two-step positive matrix factorisation (PMF) receptor analysis at a background site in Birmingham, UK using data acquired by low-cost sensors (LCSs). The application of PMF allowed for the identification of the sources that affect the local air quality, clearly separating different sources of particulate matter (PM) pollution. Furthermore, the method allowed for the contribution of different air pollution sources to the overall air quality at the site to be estimated, thereby providing pollution source apportionment. The use of data from regulatory-grade (RG) instruments further confirmed the reliability of the results, as well as further clarifying the particulate matter composition and origin. Compared with the results from a previous analysis, in which a k-means clustering algorithm was used, a good consistency between the k means and PMF results was found in pinpointing and separating the sources of pollution that affect the site. The potential and limitations of each method when used with low-cost sensor data are highlighted. The analysis presented in this study paves the way for more extensive use of LCSs for atmospheric applications, receptor modelling and source apportionment. Here, we present the infrastructure for understanding the factors that affect air quality at a significantly lower cost than previously possible. This should provide new opportunities for regulatory and indicative monitoring for both scientific and industrial applications.
22
Kozlov, Alexander, and Fedor Kapralov. "Angular Misalignment Calibration for Dual-Antenna GNSS/IMU Navigation Sensor." Sensors 23, no. 1 (December 21, 2022): 77. http://dx.doi.org/10.3390/s23010077.
Full textAbstract:
We address the angular misalignment calibration problem, which arises when a multi-antenna GNSS serves as a source of aiding information for inertial sensors in an integrated navigation system. Antennas usually occupy some outside structure of the moving carrier object, whilst an inertial measurement unit typically remains inside. Especially when using low- or mid-grade MEMS gyroscopes and accelerometers, it is either impossible or impractical to physically align IMU-sensitive axes and GNSS antenna baselines within some 1–3 degrees due to the micromechanical nature of the inertial sensors: they are just too small to have any physical reference features to align to. However, in some applications, it is desirable to line up all sensors within a fraction-of-a-degree level of accuracy. One may imagine solving this problem via the long-term averaging of sensor signals in different positions to ensure observability and then using angle differences for analytical compensation. We suggest faster calibration in special rotations using sensor fusion. Apart from quicker convergence, this method also accounts for run-to-run inertial sensor bias instability. In addition, it allows further on-the-fly finer calibration in the background when the navigation system performs its regular operation, and carrier objects may undergo gradual deformations of its structure over the years.
23
Gupta, Vinod Kumar, Njud S. Alharbie, Shilpi Agarwal, and Vladimir A. Grachev. "New Emerging One Dimensional Nanostructure Materials for Gas Sensing Application: A Mini Review." Current Analytical Chemistry 15, no. 2 (February 19, 2019): 131–35. http://dx.doi.org/10.2174/1573411014666180319151407.
Full textAbstract:
Background: Nanomaterials have numerous potential applications in many areas such as electronics, optoelectronics, catalysis and composite materials. Particularly, one dimensional (1D) nanomaterials such as nanobelts, nanorods, and nanotubes can be used as either functional materials or building blocks for hierarchical nanostructures. 1D nanostructure plays a very important role in sensor technology. Objective: In the current review, our efforts are directed toward recent review on the use of 1D nanostructure materials which are used in the literature for developing high-performance gas sensors with fast response, quick recovery time and low detection limit. This mini review also focuses on the methods of synthesis of 1D nanostructural sensor array, sensing mechanisms and its application in sensing of different types of toxic gases which are fatal for human mankind. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of 1D nanostructure sensors will have to address are also discussed.
24
González, Ernesto, Juan Casanova-Chafer, Alfonso Romero, Xavier Vilanova, Jan Mitrovics, and Eduard Llobet. "LoRa Sensor Network Development for Air Quality Monitoring or Detecting Gas Leakage Events." Sensors 20, no. 21 (October 31, 2020): 6225. http://dx.doi.org/10.3390/s20216225.
Full textAbstract:
During the few last years, indoor and outdoor Air Quality Monitoring (AQM) has gained a lot of interest among the scientific community due to its direct relation with human health. The Internet of Things (IoT) and, especially, Wireless Sensor Networks (WSN) have given rise to the development of wireless AQM portable systems. This paper presents the development of a LoRa (short for long-range) based sensor network for AQM and gas leakage events detection. The combination of both a commercial gas sensor and a resistance measurement channel for graphene chemoresistive sensors allows both the calculation of an Air Quality Index based on the concentration of reducing species such as volatile organic compounds (VOCs) and CO, and it also makes possible the detection of NO2, which is an important air pollutant. The graphene sensor tested with the LoRa nodes developed allows the detection of NO2 pollution in just 5 min as well as enables monitoring sudden changes in the background level of this pollutant in the atmosphere. The capability of the system of detecting both reducing and oxidizing pollutant agents, alongside its low-cost, low-power, and real-time monitoring features, makes this a solution suitable to be used in wireless AQM and early warning systems.
25
Chen, Kaixin, Haoling Chen, Songxian Liang, Jindan Wu, Ping Zhou, and Nan Li. "A Background-Free SERS Strategy for Sensitive Detection of Hydrogen Peroxide." Molecules 27, no. 22 (November 16, 2022): 7918. http://dx.doi.org/10.3390/molecules27227918.
Full textAbstract:
The accurate and sensitive detection of biomolecules by surface-enhanced Raman spectroscopy (SERS) is possible, but remains challenging due to the interference from biomolecules in complex samples. Herein, a new SERS sensor is developed for background-free detection of hydrogen peroxide (H2O2) with an ultralow detection limit (1 × 10−10 mol/L), using a Raman-silent strategy. The Au microparticles (Au-RSMPs) resembling rose-stones are devised as SERS substrates with a high enhancement effect, and 4-mercaptophenylboronic acid (4-MPBA) is selected as an H2O2-responsive Raman reporter. Upon the reaction with H2O2, the phenylboronic group of 4-MPBA was converted to a phenol group, which subsequently reacted with 4-diazonium-phenylalkyne (4-DP), an alkyne-carrying molecule via the azo reaction. The formed product exhibits an intense and sharp SERS signal in the Raman-silent region, avoiding interference of impurities and biomolecules. As a proof-of-concept demonstration, we show that this SERS sensor possesses significant merits towards the determination of H2O2 in terms of broad linear range, low limit of detection, and high selectivity, showing promise for the quantitative analysis of H2O2 in complicated biological samples.
26
Zhang, Xi, Na-Yan Xu, Qiong Ruan, Dan-Qing Lu, Yun-Hui Yang, and Rong Hu. "A label-free and sensitive photoluminescence sensing platform based on long persistent luminescence nanoparticles for the determination of antibiotics and 2,4,6-trinitrophenol." RSC Advances 8, no. 11 (2018): 5714–20. http://dx.doi.org/10.1039/c7ra12222e.
Full textAbstract:
A highly sensitive luminescence sensor based on PLNPs for visualized detection of antibiotic and organic explosives was developed, which could eliminate the background interference, allowing low background and therefore high sensitivity.
27
Zhang, Yuxin, Pari Delir Haghighi, Frada Burstein, Lim Wei Yap, Wenlong Cheng, Lina Yao, and Flavia Cicuttini. "Electronic Skin Wearable Sensors for Detecting Lumbar–Pelvic Movements." Sensors 20, no. 5 (March 9, 2020): 1510. http://dx.doi.org/10.3390/s20051510.
Full textAbstract:
Background: A nanomaterial-based electronic-skin (E-Skin) wearable sensor has been successfully used for detecting and measuring body movements such as finger movement and foot pressure. The ultrathin and highly sensitive characteristics of E-Skin sensor make it a suitable alternative for continuously out-of-hospital lumbar–pelvic movement (LPM) monitoring. Monitoring these movements can help medical experts better understand individuals’ low back pain experience. However, there is a lack of prior studies in this research area. Therefore, this paper explores the potential of E-Skin sensors to detect and measure the anatomical angles of lumbar–pelvic movements by building a linear relationship model to compare its performance to clinically validated inertial measurement unit (IMU)-based sensing system (ViMove). Methods: The paper first presents a review and classification of existing wireless sensing technologies for monitoring of body movements, and then it describes a series of experiments performed with E-Skin sensors for detecting five standard LPMs including flexion, extension, pelvic tilt, lateral flexion, and rotation, and measure their anatomical angles. The outputs of both E-Skin and ViMove sensors were recorded during each experiment and further analysed to build the comparative models to evaluate the performance of detecting and measuring LPMs. Results: E-Skin sensor outputs showed a persistently repeating pattern for each movement. Due to the ability to sense minor skin deformation by E-skin sensor, its reaction time in detecting lumbar–pelvic movement is quicker than ViMove by ~1 s. Conclusions: E-Skin sensors offer new capabilities for detecting and measuring lumbar–pelvic movements. They have lower cost compared to commercially available IMU-based systems and their non-invasive highly stretchable characteristic makes them more comfortable for long-term use. These features make them a suitable sensing technology for developing continuous, out-of-hospital real-time monitoring and management systems for individuals with low back pain.
28
Leal-Junior, Arnaldo G., Anselmo Frizera, and Carlos Marques. "Low-cost Fiberoptic Probe for Ammonia Early Detection in Fish Farms." Remote Sensing 12, no. 9 (May 1, 2020): 1439. http://dx.doi.org/10.3390/rs12091439.
Full textAbstract:
Recirculating aquaculture systems (RAS) are complex systems in which there is an interaction between the fish biomass and water chemistry, where small variations in the environment can lead to major effects in the production. Ammonia is one of the key limiting factors in RAS and its early detection in small concentrations prevents fish mortality and improves the production quality. Aiming at this background, this paper presents a low-cost fiberoptic probe for the early detection of ammonia. The sensor was based on the chemical interaction between the Oxazine 170 perchlorate layer, deposited in an uncladed polymer optical fiber (POF), and the ammonia dissolved in water. In addition, a thin metallic layer (composed by gold and palladium) was deposited in the fiber end facet and acted as a reflector for the optical signals, enabling the use of the proposed sensor in reflection mode. Different configurations of the sensor were tested, where the effects of polydimethylsiloxane (PDMS) protective layer, thermal treatments, and the use on reflection or transmission modes were compared in the assessment of ammonia concentrations in the range of 100 ppb to 900 ppb. Results showed a better performance (as a function of the sensor sensitivity and linearity) of the sensor with the annealing thermal treatment and without the PDMS layer. Then, the proposed fiberoptic probe was applied on the ammonia detection in high-salinity water, where ammonia concentrations as low as 100 ppb were detected.
29
Bigi, Alessandro, Michael Mueller, Stuart K. Grange, Grazia Ghermandi, and Christoph Hueglin. "Performance of NO, NO<sub>2</sub> low cost sensors and three calibration approaches within a real world application." Atmospheric Measurement Techniques 11, no. 6 (June 26, 2018): 3717–35. http://dx.doi.org/10.5194/amt-11-3717-2018.
Full textAbstract:
Abstract. Low cost sensors for measuring atmospheric pollutants are experiencing an increase in popularity worldwide among practitioners, academia and environmental agencies, and a large amount of data by these devices are being delivered to the public. Notwithstanding their behaviour, performance and reliability are not yet fully investigated and understood. In the present study we investigate the medium term performance of a set of NO and NO2 electrochemical sensors in Switzerland using three different regression algorithms within a field calibration approach. In order to mimic a realistic application of these devices, the sensors were initially co-located at a rural regulatory monitoring site for a 4-month calibration period, and subsequently deployed for 4 months at two distant regulatory urban sites in traffic and urban background conditions, where the performance of the calibration algorithms was explored. The applied algorithms were Multivariate Linear Regression, Support Vector Regression and Random Forest; these were tested, along with the sensors, in terms of generalisability, selectivity, drift, uncertainty, bias, noise and suitability for spatial mapping intra-urban pollution gradients with hourly resolution. Results from the deployment at the urban sites show a better performance of the non-linear algorithms (Support Vector Regression and Random Forest) achieving RMSE < 5 ppb, R2 between 0.74 and 0.95 and MAE between 2 and 4 ppb. The combined use of both NO and NO2 sensor output in the estimate of each pollutant showed some contribution by NO sensor to NO2 estimate and vice-versa. All algorithms exhibited a drift ranging between 5 and 10 ppb for Random Forest and 15 ppb for Multivariate Linear Regression at the end of the deployment. The lowest concentration correctly estimated, with a 25 % relative expanded uncertainty, resulted in ca. 15–20 ppb and was provided by the non-linear algorithms. As an assessment for the suitability of the tested sensors for a targeted application, the probability of resolving hourly concentration difference in cities was investigated. It was found that NO concentration differences of 5–10 ppb (8–10 for NO2) can reliably be detected (90 % confidence), depending on the air pollution level. The findings of this study, although derived from a specific sensor type and sensor model, are based on a flexible methodology and have extensive potential for exploring the performance of other low cost sensors, that are different in their target pollutant and sensing technology.
30
Romashkin, Alexey V., Andrey V. Lashkov, Victor V. Sysoev, Nikolay S. Struchkov, Evgeny V. Alexandrov, and Denis D. Levin. "Energy-Efficient Chemiresistive Sensor Array Based on SWCNT Networks, WO3 Nanochannels and SWCNT-Pt Heterojunctions for NH3 Detection against the Background Humidity." Chemosensors 10, no. 11 (November 12, 2022): 476. http://dx.doi.org/10.3390/chemosensors10110476.
Full textAbstract:
Recently, promising results have been achieved in improving the sensitivity to ammonia in gas sensors through the use of structures composed of heterojunctions or nanochannels. However, their sensitivity is highly dependent on the background humidity under air conditions. The sensor structures which could ensure selective ammonia detection with a low detection limit, despite interference from changing background humidity, remain highly demanded. In this work, we consider sensing units containing (i) nanochannels formed by a continuous tungsten oxide nanolayer to appear in contact between single-walled carbon nanotubes (SWCNTs) and a Pt sublayer and (ii) SWCNT-Pt junctions in frames of mass-scale microelectronic technologies. SWCNTs were deposited by spray-coating on a thin WO3/Pt/W sublayer formed by a photolithographic pattern to be accompanied by satellite samples with just SWCNTs for reference purposes. We elucidate the specific differences that appeared in the response of sensors based on SWCNT-Pt junctions and WO3 nanochannels relative to satellite SWCNT samples with a similar SWCNT network density. Particularly, while a similar response to NH3 vapors mixed with dry air is observed for each sensor type, the response to NH3 is reduced significantly in the presence of background humidity, of 45 rel.%, especially in the case of WO3 nanochannel structures even at room temperature. A multisensor array based on the four various sensing structures involving SWCNT-Pt junctions, WO3 nanochannels, and their satellite-only-SWCNT ones allowed us to determine a correct ammonia concentration via utilizing the linear discriminant analysis despite the presence of background air humidity. Thus, such an energy-efficient multisensor system can be used for environmental monitoring of ammonia content, health monitoring, and other applications.
31
Wesseling, Joost, Wouter Hendricx, Henri de Ruiter, Sjoerd van Ratingen, Derko Drukker, Maaike Huitema, Claar Schouwenaar, et al. "Assessment of PM2.5 Exposure during Cycle Trips in The Netherlands Using Low-Cost Sensors." International Journal of Environmental Research and Public Health 18, no. 11 (June 3, 2021): 6007. http://dx.doi.org/10.3390/ijerph18116007.
Full textAbstract:
Air pollution, especially fine particulate matter (PM2.5), is a major environmental risk factor for human health in Europe. Monitoring of air quality takes place using expensive reference stations. Low-cost sensors are a promising addition to this official monitoring network as they add spatial and temporal resolution at low cost. Moreover, low-cost sensors might allow for better characterization of personal exposure to PM2.5. In this study, we use 500 dust (PM2.5) sensors mounted on bicycles to estimate typical PM2.5 levels to which cyclists are exposed in the province of Utrecht, the Netherlands, in the year 2020. We use co-located sensors at reference stations to calibrate and validate the mobile sensor data. We estimate that the average exposure to traffic related PM2.5, on top of background concentrations, is approximately 2 μg/m3. Our results suggest that cyclists close to major roads have a small, but consistently higher exposure to PM2.5 compared to routes with less traffic. The results allow for a detailed spatial representation of PM2.5 concentrations and show that choosing a different cycle route might lead to a lower exposure to PM2.5. Finally, we conclude that the use of mobile, low-cost sensors is a promising method to estimate exposure to air pollution.
32
Kulkarni, A. S., M. Suchetha, and N. Kumaravel. "IoT based Low Power Wearable ECG Monitoring System." Current Signal Transduction Therapy 14, no. 1 (March 11, 2019): 68–74. http://dx.doi.org/10.2174/1574362413666180622105447.
Full textAbstract:
Background: An electrocardiogram device monitors the cardiac status of a patient by recording the heart’s electrical potential vs time. Such devices play a very important role to save the life of patients who survive a heart attack or suffer from these patients. An early detection of conditions that lead to the onset of cardiac arrest allows doctors to provide proper treatment on time and prevents death or disability from cardiac arrest. Most developing countries have very poor information about these health care issues. Methods: An actual deployment of the system was used to evaluate key aspects of the system architecture, in particular, the possibility to monitor the ECG signal of single patients in a large area and for a long time the possibility to access ECG data through the web interface. The test deployment consisted of ECG sensor AD8232, wi-fi module and IoT server. The IoT server was installed on a Linux/ windows machine. The wifi has been configured to connect to the server, through an ADSL router. Conclusion: We have proposed a wireless wearable ECG monitoring system enabled with an IoT platform that integrates heterogeneous nodes of ECG sensor and applications, has a long battery life and provides a high-quality ECG signal. The system allows monitoring single/multiple patients on a relatively large indoor area (home, building, nursing home, etc). As observed, this result is obtained through a careful set of choices at the level of components, circuit solutions, and algorithms. We would like to stress the fact that a dedicated overall output is not enough to achieve an advantage in terms of overall sensor performance. The latter depends on the optimization of the whole sensor. Indeed, this proposed ECG sensor, based on a high-performance ADC and an arm processor, provides much better performance, in terms of power consumption and noise, than many proposed system based on a purposely designed front-end chip.
33
Zhou, Ying, Xiao-Jing Xing, Dai-Wen Pang, and Hong-Wu Tang. "An exonuclease III-aided “turn-on” fluorescence assay for mercury ions based on graphene oxide and metal-mediated “molecular beacon”." RSC Advances 5, no. 17 (2015): 12994–99. http://dx.doi.org/10.1039/c4ra14024a.
Full text
34
Goswami, Manash Protim, Sudipta Hazarika, Durlove Bora, and Utpal Sarma. "WSN Based Embedded System for Field Parameter Monitoring Inside a Low-Cost Polyhouse." International Journal of Sensors, Wireless Communications and Control 10, no. 3 (November 2, 2020): 354–67. http://dx.doi.org/10.2174/2210327909666190409114420.
Full textAbstract:
Background & Objective:: This paper presents a wireless sensor network for monitoring field parameters inside a low-cost polyhouse. The micro climate inside a polyhouse differs from that on the outside, which provides a favorable condition for unseasonal crops. Methods: The physical parameters associated with the polyhouse’s microclimate were monitored by a reliable low-cost wireless sensor network, which in turn helps to take decisions for enhancing yield quality and quantity. Sensor network development, signal conditioning, calibration of the soil temperature measurement system and field experience of the installed system are discussed in this paper. The field parameters for the growing period of cucumber (Cucumis sativus) inside the polyhouse are provided in the paper. Results & Conclusion: It showed significant variations in temperature, relative humidity and wind speed inside the polyhouse to that of the outside. It was also observed that soil temperature, soil moisture in mulched soil differed from that of the open condition. Enhancement of the crop yield was found for mulched soil.
35
Murshudov, R., J. M. Watson, C. W. Liang, J. Sexton, and M. Missous. "Optimising sensor pitch for magnetic flux leakage imaging systems." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 7 (July 1, 2021): 416–21. http://dx.doi.org/10.1784/insi.2021.63.7.416.
Full textAbstract:
Sensor arrays can significantly increase the speed at which inspections and subsequent imaging of flaws is performed[1]. This work focuses on developing a software approach for optimising the spacing between quantum well Hall-effect (QWHE) magnetic sensors used for magnetic flux leakage (MFL) imaging, where this approach could be adapted for any non-destructive evaluation (NDE) technique in which imaging is obtained. A ground mild steel weld sample containing two surface-breaking flaws prepared by Sonaspection was scanned using an XYZ MFL imaging system developed at the University of Manchester[2,3,13,14]. The scan was taken with an autonomously controlled lift-off height of 0.75 mm, with an x-y measurement step of 100 μm and an applied magnetic field of 30 mT root mean square (RMS) at a frequency of 400 Hz. This data (ie magnetic image) was then processed to simulate different measurement step sizes, to determine any relationship between step size and flaw detectability (flaw signal to weld background response). This work effectively simulates different sensor pitches (separation between sensors) of integrated QWHE sensor arrays from 100 μm to 5 mm, with the goal of determining both the minimum number of sensors required in the array and the optimal spacing to maximise scan speeds and help determine optimum inspection parameters to develop the technology of low-power MFL imaging. This optimisation process could be applied to any NDE imaging system (electromagnetic or other) currently used, with results dependent on the inspection parameters.
36
Gilavdary, I. Z., S. N. Mekid, and N. N. Riznookaya. "PARAMETRIC AMPLIFICATION OF THE SIGNALS IN THE ELECTROSTATIC GRAVIINERTIAL SENSOR." Devices and Methods of Measurements 8, no. 2 (June 9, 2017): 108–21. http://dx.doi.org/10.21122/2220-9506-2017-8-2-108-121.
Full textAbstract:
The challenges of designing simple, reliable, and high sensitivity graviinertial sensors are investigated. The sensor comprises a proof mass (PM) and is fixed with the housing by the elastic torsion suspension. PM makes small rotations under the action of gravitational forces or inertial forces.The distinctive features of the sensor are that the differential electrostatic system provides simultaneous reading of the desired signal and a control the torsional rigidity of suspension. In addition, the PM's rotational angular velocity transforms in the alternating current flowing through the capacitors. The presence of аlternating current (AC) voltage sources allows to get the parametric amplification of AC and significantly to improve the sensitivity of the sensor. In the simplest case, the sensor does not contain any feedback circuits.As an example, calculations of the micromechanical linear accelerations confirm that the periodic modulation of the coefficient of elastic stiffness of the suspension can significantly increase the sensitivity in the low frequency range, even in the absence of parametric resonance.Conditions for suppressions of background current participating in the output signal from a parametric pumping due to the asymmetry of the differential circuits are set. The frequency characteristics calculations of the sensor were carried out. It is expected, that the proposed sensor design ensures minimum noise level, which can be achievable in the graviinertial sensors. This design and the constructed theory can serve as a basis for creating a wide range of graviinertial devices operating on a movable base, for example, linear and angular accelerometer, gravity gradiometer, gravimeters, and inclinometers, which can be realized in the hybrid and in the micromechanical versions.
37
Joddrell, Phil, Stephen Potter, Luc P. de Witte, and Mark S. Hawley. "Continuous in-home walking speed monitoring in older people with a low-cost ambient sensor: Results of a feasibility study." Technology and Disability 33, no. 2 (May 13, 2021): 77–85. http://dx.doi.org/10.3233/tad-200316.
Full textAbstract:
BACKGROUND: Walking speed predicts important clinical outcomes in older adults and is one of the most significant indicators of frailty. OBJECTIVE: To test whether it is feasible to measure walking speed frequently and unobtrusively in the home. METHODS: A longitudinal feasibility study was conducted comprising the installation and monitoring of continuous measurement walking speed sensors in twenty frail older adults’ homes for a period of twelve weeks (eighteen participants completed the study). Manual walking speed, frailty level and health status were measured at four-weekly intervals. Qualitative interviews were conducted at the end of the study to assess participants’ attitudes to the sensors and to the concept of continuous in-home walking speed measurement. RESULTS: There was a high degree of variance to the number of walking speed measurements recorded by each participant’s sensor (median 1942.39, range 2-3617). Participants indicated acceptability of both the sensor within the home and the concept of in-home walking speed measurement. CONCLUSIONS: Where regular measurement was achieved, the results indicate that walking speed might be better viewed as a distribution rather than a single figure, taking into account the natural variation to walking speed in daily life. This study demonstrates the feasibility of continuous ambient in-home walking speed monitoring of older adults with a low-cost, easily deployed device.
38
Gunache (Roșca), Ramona Oana, Alexandra Virginia Bounegru, and Constantin Apetrei. "Determination of Atorvastatin with Voltammetric Sensors Based on Nanomaterials." Inventions 6, no. 3 (August 12, 2021): 57. http://dx.doi.org/10.3390/inventions6030057.
Full textAbstract:
This paper presents an accurate and fast electrochemical method for atorvastatin determination in pharmaceutical products. Two screen-printed sensors, one—carbon based (SPCE) and one based on carbon nanotubes and gold nanoparticles (AuNP-CNT/SPCE) were used during the electrochemical analyses. At all experimental stages, cyclic voltammetry was employed, both for the characterization of the sensors and their electrochemical behavior, and for quantitative determinations. AuNP-CNT/SPCE has showed an extended active area, higher intensity peaks, better reversibility and lower background current than the unmodified sensor. For atorvastatin quantification, a calibration curve has been developed within the 1.2–606.25 µM concentration range. A linearity relation between the current of the anodic peak and concentration has been obtained in the range 1.2–53.33 µMfor both sensors. With the AuNP-CNT/SPCE sensor, low values of limit of detection, LOD (1.92 × 10−7 M) and limit of quantification, LOQ (6.39 × 10−7 M) have been obtained, which demonstrates the feasibility of the method of determining atorvastatin from real samples. Atorvastatin amount has been successfully determined from pharmaceutical products using AuNP-CNT/SPCE. The results were similar to the manufacturer’s specifications regarding the dosage per tablet and to the concentrations obtained by applying the FTIR spectrometric method.
39
Wang, Li, Zhen Li, Ming Li, Shao Li, Yingchun Lu, Ning Qi, Jian Zhang, Chao Xie, Chunyan Wu, and Lin-Bao Luo. "Self-Powered Filterless Narrow-Band p–n Heterojunction Photodetector for Low Background Limited Near-Infrared Image Sensor Application." ACS Applied Materials & Interfaces 12, no. 19 (April 22, 2020): 21845–53. http://dx.doi.org/10.1021/acsami.0c02827.
Full text
40
Oladayo, Olakanmi, and Abbas Ashraf. "A Secure and Energy-Aware Routing Protocol for Optimal Routing in Mobile Wireless Sensor Networks (MWSNs)." International Journal of Sensors, Wireless Communications and Control 9, no. 4 (September 17, 2019): 507–20. http://dx.doi.org/10.2174/2210327909666181217105028.
Full textAbstract:
Background and Objective: Mobile Wireless Sensor Network (MWSN) is a specialized wireless network made up of large number of mobile sensors, where each sensor is capable of changing its location, relaying data to either the base station or neighbouring nodes. MWSN has emerged as a useful integral part of modern communication systems; however, its major performance challenges are lack of data delivery assurance due to mobility of its sensors, low computational power of its nodes, and some security related issues. Methods: Most of the existing WSN routing protocols are for non-mobile sensors and require considerably high computational power. Thus, not suitable for energy-constraint WSN with mobile sensors. Therefore, there is need for a secure protocol for MWSN with mechanisms that take into account the limited resources of the nodes and dynamism of its nodes’ locations. Results: In this paper, an efficient routing protocol for MWSN is proposed, not to only improve data delivery but to ensure reliability. This protocol is capable of selecting optimal multi-hop route among available routes for the source node and securely hops the data to the destination nodes through intermediary nodes. Formal and informal security analysis of the routing protocol is done to ascertain the required security level of the protocol. In addition, computational cost analysis is done to evaluate the computational cost of the protocol. Conclusion: The analysis results showed that the proposed protocol was secure and required low computational cost.
41
SEELEY, JULIETTE A., MATTHEW ANGEL, ROSHAN L. AGGARWAL, THOMAS H. JEYS, ANTONIO SANCHEZ-RUBIO, WILLIAM DINATALE, and JONATHAN M. RICHARDSON. "INEXPENSIVE CHEMICAL DEFENSE NETWORK FOR A FIXED SITE." International Journal of High Speed Electronics and Systems 18, no. 03 (September 2008): 593–600. http://dx.doi.org/10.1142/s012915640800559x.
Full textAbstract:
The Inexpensive Chemical Agent Detection System (ICADS) consists of a network of affordable line-of-sight sensors, each designed to detect chemical threats passing between two points with high sensitivity and a low false-alarm rate. Each leg of the ICADS system is composed of two devices, a broadband IR transmitter, and a receiver containing a long-wave-IR spectrometer. The spectrometer continually measures the spectrum of the radiation emitted by the transmitter, which is separated from the receiver by up to several hundred meters, forming a line of protection. A chemical vapor or aerosol plume with sufficient long-wave-IR absorption causes a characteristic change in the spectrum of light collected by the receiver as the plume crosses the protected line, signaling a threat. Background measurements were conducted to determine background-limited performance. Additionally, a sensor composed of a long-wave-IR fixed-grating spectrometer and a hot-filament transmitter was designed and built. Measurements of the signal-to-noise ratio (SNR) and resolution agree with our analytical model and meet sensor requirements.
42
Ye, Qing, Si Meng Yu, and Yi Sun. "Design and Implementation of the Security Subsystem in the Smart Home System." Applied Mechanics and Materials 644-650 (September 2014): 3906–10. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.3906.
Full textAbstract:
The current mainstream security systems are independent existence. They are too complex to achieve for the average families.The networking technology and smart home technology has been developed mature.And the home automation and intelligent basically achieved.It's low-cost and low-hanging to integrate Home security into smart home. Scheme of Adding the home system based on the current smart security module was proposed.The MCU is CC430F5137 produced by TI,and the monitored is finished by the temperature sensor MAX6662,humidity sensor HS1101, smoke sensor MQ-2 detector and camera and other hardware equipments. And complete the interaction with the server through the RF433MHz wireless communication mode, the server finish background analysis and notify the user by the client software.
43
Yola, Mehmet Lütfi. "Development of Novel Nanocomposites Based on Graphene/Graphene Oxide and Electrochemical Sensor Applications." Current Analytical Chemistry 15, no. 2 (February 19, 2019): 159–65. http://dx.doi.org/10.2174/1573411014666180320111246.
Full textAbstract:
Background: Until now, several methods such as spectroscopic methods and chromatographic techniques have been developed for the determination of biomolecules, drug or heavy metals. Nevertheless, the crucial interference problems are present in these methods. Due to these reasons, more sensitive, favorable portability, low-cost, simple and selective sensors based on nanocomposites are needed in terms of health safety. In the development of electrochemical nanosensor, the nanomaterials such as graphene/graphene oxide, carbon and carbon nitride nanotubes are utilized to improve the sensitivity. Objective: The nanomaterials such as graphene/graphene oxide, carbon and carbon nitride nanotubes have important advantages such as high surface area, electrical conductivity, thermal and mechanical stability. Hence, we presented the highly selective methods for sensitive sensor applications by molecular imprinting technology in literature. This technology is a polymerization method around target molecule. This method provides the specific cavities to analyte molecule on the polymer surface. Hence, the selective sensor is easily created for biomedical and other applications. Novel electrochemical sensors based on nanocomposite whose surface is coated with Molecular Imprinting Polymer (MIP) are developed and then applied to the selective and sensitive detection in this study. Until now, we have presented several reports about nanocomposite based sensor with MIP.
44
Mirzaei, Ali, Jae-Hun Kim, Hyoun Woo Kim, and Sang Sub Kim. "Gasochromic WO3 Nanostructures for the Detection of Hydrogen Gas: An Overview." Applied Sciences 9, no. 9 (April 29, 2019): 1775. http://dx.doi.org/10.3390/app9091775.
Full textAbstract:
Hydrogen is one of the most important gases that can potentially replace fossil fuels in the future. Nevertheless, it is highly explosive, and its leakage should be detected by reliable gas sensors for safe operation during storage and usage. Most hydrogen gas sensors operate at high temperatures, which introduces the risk of hydrogen explosion. Gasochromic WO3 sensors work based on changes in their optical properties and color variation when exposed to hydrogen gas. They can work at low or room temperatures and, therefore, are good candidates for the detection of hydrogen leakage with low risk of explosion. Once their morphology and chemical composition are carefully designed, they can be used for the realization of sensitive, selective, low-cost, and flexible hydrogen sensors. In this review, for the first time, we discuss different aspects of gasochromic WO3 gas sensor-based hydrogen detection. Pristine, heterojunction, and noble metal-decorated WO3 nanostructures are discussed for the detection of hydrogen gas in terms of changes in their optical properties or visible color. This review is expected to provide a good background for research work in the field of gas sensors.
45
Xu, Qichang. "Using Sensor Network in Motion Detection Based on Deep Full Convolutional Network Model." Complexity 2021 (May 20, 2021): 1–11. http://dx.doi.org/10.1155/2021/3909522.
Full textAbstract:
Aiming at the shortcomings of traditional moving target detection methods in complex scenes such as low detection accuracy and high complexity, and not considering the overall structure information of the video frame image, this paper proposes a moving-target detection based on sensor network. First, a low-power motion detection wireless sensor network node is designed to obtain motion detection information in real time. Secondly, the background of the video scene is quickly extracted by the time domain averaging method, and the video sequence and the background image are channel-merged to construct a deep full convolutional network model. Finally, the network model is used to learn the deep features of the video scene and output the pixel-level classification results to achieve moving target detection. This method not only can adapt to complex video scenes of different sizes but also has a simple background extraction method, which effectively improves the detection speed.
46
Tawfik, Mohamed W., Abdelhameed Sharaf, and Mohamed Serry. "Monolayer Graphene Radiation Sensor with Backend RF Ring Oscillator Transducer." Nanomaterials 12, no. 3 (January 18, 2022): 305. http://dx.doi.org/10.3390/nano12030305.
Full textAbstract:
This paper proposes a new graphene gamma- and beta-radiation sensor with a backend RF ring oscillator transducer employed to convert the change in the graphene resistivity due to ionizing irradiation into a frequency output. The sensor consists of a CVD monolayer of graphene grown on a copper substrate, with an RF ring oscillator readout circuit in which the percentage change in frequency is captured versus the change in radiation dose. The novel integration of the RF oscillator transducer with the graphene monolayer results in high average sensitivity to gamma irradiation up to 3.82 kΩ/kGy, which corresponds to a percentage change in frequency of 7.86% kGy−1 in response to cumulative gamma irradiation ranging from 0 to 1 kGy. The new approach helps to minimize background environmental effects (e.g., due to light and temperature), leading to an insignificant error in the output change in frequency of the order of 0.46% when operated in light versus dark conditions. The uncertainty in readings due to background light was analyzed, and the error in the resistance was found to be of the order of 1.34 Ω, which confirms the high stability and selectivity of the proposed sensor under different background effects. Furthermore, the evolution of the graphene’s lattice defect density due to radiation was observed using Raman spectroscopy and SEM, indicating a lattice defect density of up to 1.780 × 1011/cm2 at 1 kGy gamma radiation, confirming the increase in the graphene resistance and proving the graphene’s sensitivity. In contrast, the graphene’s defect density in response to beta radiation was 0.683 × 1011/cm2 at 3 kGy beta radiation, which is significantly lower than the gamma effects. This can be attributed to the lower p-doping effect caused by beta irradiation in ambient conditions, compared with that caused by gamma irradiation. Morphological analysis was used to verify the evolution of the microstructural defects caused by ionizing irradiation. The proposed sensor monitors the low-to-medium cumulative range of ionizing radiations ranging from 0 to 1 kGy for gamma radiation and 0 to 9 kGy for beta radiation, with high resolution and selectivity, filling the research gap in the study of graphene-based radiation sensors at low-to-medium ionizing radiation doses. This range is essential for the pharmaceutical and food industries, as it spans the minimum range for affecting human health, causing cancer and DNA damage.
47
Demars, Casey, Michael Roggemann, Adam Webb, and Timothy Havens. "Target Localization and Tracking by Fusing Doppler Differentials from Cellular Emanations with a Multi-Spectral Video Tracker." Sensors 18, no. 11 (October 30, 2018): 3687. http://dx.doi.org/10.3390/s18113687.
Full textAbstract:
We present an algorithm for fusing data from a constellation of RF sensors detecting cellular emanations with the output of a multi-spectral video tracker to localize and track a target with a specific cell phone. The RF sensors measure the Doppler shift caused by the moving cellular emanation and then Doppler differentials between all sensor pairs are calculated. The multi-spectral video tracker uses a Gaussian mixture model to detect foreground targets and SIFT features to track targets through the video sequence. The data is fused by associating the Doppler differential from the RF sensors with the theoretical Doppler differential computed from the multi-spectral tracker output. The absolute difference and the root-mean-square difference are computed to associate the Doppler differentials from the two sensor systems. Performance of the algorithm was evaluated using synthetically generated datasets of an urban scene with multiple moving vehicles. The presented fusion algorithm correctly associates the cellular emanation with the corresponding video target for low measurement uncertainty and in the presence of favorable motion patterns. For nearly all objects the fusion algorithm has high confidence in associating the emanation with the correct multi-spectral target from the most probable background target.
48
Beer, Maik, Jan Haase, Jennifer Ruskowski, and Rainer Kokozinski. "Background Light Rejection in SPAD-Based LiDAR Sensors by Adaptive Photon Coincidence Detection." Sensors 18, no. 12 (December 8, 2018): 4338. http://dx.doi.org/10.3390/s18124338.
Full textAbstract:
Light detection and ranging (LiDAR) systems based on silicon single-photon avalanche diodes (SPAD) offer several advantages, like the fabrication of system-on-chips with a co-integrated detector and dedicated electronics, as well as low cost and high durability due to well-established CMOS technology. On the other hand, silicon-based detectors suffer from high background light in outdoor applications, like advanced driver assistance systems or autonomous driving, due to the limited wavelength range in the infrared spectrum. In this paper we present a novel method based on the adaptive adjustment of photon coincidence detection to suppress the background light and simultaneously improve the dynamic range. A major disadvantage of fixed parameter coincidence detection is the increased dynamic range of the resulting event rate, allowing good measurement performance only at a specific target reflectance. To overcome this limitation we have implemented adaptive photon coincidence detection. In this technique the parameters of the photon coincidence detection are adjusted to the actual measured background light intensity, giving a reduction of the event rate dynamic range and allowing the perception of high dynamic scenes. We present a 192 × 2 pixel CMOS SPAD-based LiDAR sensor utilizing this technique and accompanying outdoor measurements showing the capability of it. In this sensor adaptive photon coincidence detection improves the dynamic range of the measureable target reflectance by over 40 dB.
49
Lang, Jianjun, and Qigang Jiang. "An Energy-Efficient and Low-Latency MAC Protocol Based on Adaptive Coordination Contention Window for Wireless Sensor Networks." Open Electrical & Electronic Engineering Journal 8, no. 1 (December 31, 2014): 658–63. http://dx.doi.org/10.2174/1874129001408010658.
Full textAbstract:
Wireless sensor network (WSN) consists of massive small sensor nodes which are located in monitoring region, the target of which is to cooperatively sense, collect and process the information of objects in the coverage area, then send the information to the observer through wireless communication. It can be widely used in military applications, medical treatment, traffic, environment monitoring and so on. Medium Access Control (MAC) Protocol, which decides how to share the wireless channel, allocates the limited communication resource among nodes and a good MAC protocol can save lots of energy and reduce collision. Firstly the thesis analyzed the research background and the current situation at home and abroad, and then discussed the structural characteristics of wireless sensor networks and other content, in which indicating the energy consumption of the wireless sensor network; Then, the thesis compared and analyzed the MAC protocols of the wireless sensor Network, focusing on competition-based MAC protocol S-MAC protocol in detail. From the shortcomings of the thesis proposed a new study of the improved protocol basing on the random work sleep scheduling mechanism; Finally, the thesis simulated the improving the MAC protocol, showing that the performances of the improved protocol are better than the original in improving energy efficiency, delay, throughput and so on from the analysis of simulation results.
50
Al-Shorman, Mohammad Y., Majd M. Al-Kofahi, and Osameh M. Al-Kofahi. "A practical microwatt-meter for electrical energy measurement in programmable devices." Measurement and Control 51, no. 9-10 (August 20, 2018): 383–95. http://dx.doi.org/10.1177/0020294018794350.
Full textAbstract:
Background: In this work, an accurate low-cost power microwatt-meter is designed, built, and tested. This microwatt-meter is found to be capable of measuring power consumption in a wide range of devices and sensors, such as nodes in wireless sensor networks, microcontrollers in Internet of Things devices, and Field Programmable Gate Arrays. Methods: The paper examines the usage of the microwatt-meter for the measurement of power consumption in digital devices as they execute program instructions, ranging from a low-level single step (instruction) in an assembly program to a high-level sophisticated program or system. Results: The results obtained showed that the microwatt-meter is highly accurate. It can measure the energy consumed by any of the devices/programs/instructions in a digital system with accuracy levels ranging between 0.5% and 2.5% (depending on the application). Conclusion: The accuracy of the microwatt-meter is validated using the fundamental conservation of energy law and a comparison with multimeter current measurements is presented.