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pressure sensor

Yedhu Krishna, Sean O'Byrne, Kannan Munuswamy, Gopalan Jagadeesh
Tunable diode laser absorption spectroscopy is being widely used to make sensors for diagnostic purposes in various engineering applications. Since the wavelength of many diode lasers used in such sensors is sensitive to the driving current, even noise as small as a few μArms in the driving current can cause a wavelength fluctuation of ∼±0.5  pm, which is large enough to interfere with sensitive absorption measurements. Although these fluctuations are small, they can cause significant systematic error in measured absorption spectra in applications where the absorption line probed is narrow, as is the case for low-density hypersonic flows...
June 10, 2018: Applied Optics
Dervil Cody, Sabad-E Gul, Tatsiana Mikulchyk, Muhammad Irfan, Anastasia Kharchenko, Kamila Goldyn, Suzanne Martin, Svetlana Mintova, John Cassidy, Izabela Naydenova
The aim of this paper is to discuss the benefits as well as the limitations of utilizing photopolymer materials in the design of holograms that are responsive to changes in their environment, such as changes in the concentration of a specific substance, temperature, and pressure. Three different case studies are presented, including both surface and volume phase holograms, in order to demonstrate the flexibility in the approach of utilizing holographic photopolymers for the design of sensors and interactive optical devices...
August 1, 2018: Applied Optics
Mark Lubinsky
Common human reproductive inefficiencies have multiple etiologies. Going against chance, many effects, such as polycystic ovaries, endometriosis, and folate metabolic issues, have genetic components, while aneuploid losses arise from diverse mitotic and meiotic errors at different stages, some transitory. This can be advantageous, since greater overall survival with fewer offspring can increase reproductive success. Benefits primarily accrue to mothers, who bear most child related costs, and for whom early losses are less costly than late...
August 16, 2018: Journal of Assisted Reproduction and Genetics
Sunit Tolia, Zubair Khan, Gunjan Gholkar, Marcel Zughaib
Background: Routine ambulatory echocardiographic estimates of left ventricular (LV) filling pressures are not cost-effective and are occasionally fraught with anatomic, physiologic as well as logistical limitations. The use of implantable hemodynamic devices such as CardioMEMS Heart Failure (HF) System has been shown to reduce HF-related readmission rates by remote monitoring of LV filling pressures. Little is known about the correlation between CardioMEMS and echocardiography-derived estimates of central hemodynamics...
2018: Cardiology Research and Practice
Andrius Dzedzickis, Vytautas Bucinskas, Darius Viržonis, Nikolaj Sesok, Arturas Ulcinas, Igor Iljin, Ernestas Sutinys, Sigitas Petkevicius, Justinas Gargasas, Inga Morkvenaite-Vilkonciene
Increasing the imaging rate of atomic force microscopy (AFM) without impairing of the imaging quality is a challenging task, since the increase in the scanning speed leads to a number of artifacts related to the limited mechanical bandwidth of the AFM components. One of these artifacts is the loss of contact between the probe tip and the sample. We propose to apply an additional nonlinear force on the upper surface of a cantilever, which will help to keep the tip and surface in contact. In practice, this force can be produced by the precisely regulated airflow...
August 16, 2018: Sensors
Zhao Wang, Guangrui Wen, Zutang Wu, Jun Yang, Liqiang Chen, Wenxiang Liu
Most of fiber-optic pressure sensors used in shock wave measurements are based on deformations of sensing elements. These approaches result in low dynamic pressure ranges for these sensors used in the air. A novel fiber-optic method based on the relationship between pressure and the acceleration of a diaphragm is proposed to obtain peak reflected pressure of shock waves in the air. The optical sensor is designed with a thin circular diaphragm as the sensing element, and the Fabry-Perot optical interferometry is used to detect the acceleration of the diaphragm...
June 11, 2018: Optics Express
Jayaraj Joseph, Nabeel P M, Malay Ilesh Shah, Mohanasankar Sivaprakasam
OBJECTIVE: Assessment of local arterial properties has become increasingly important in cardiovascular research as well as in clinical domains. Vascular wall stiffness indices are related to local pulse pressure (ΔP) level, mechanical and geometrical characteristics of the arterial vessel. Non-invasive evaluation of local ΔP from the central arteries (aorta and carotid) is not straightforward in a non-specialist clinical setting. In this work, we present a method and system for real-time and beat-by-beat evaluation of local ΔP from superficial arteries-a non-invasive, cuffless and calibration-free technique...
2018: PloS One
Zengtao Hou, Zhaolan Yang, Dazhong Xu, Qinli Zhang, Peng Shang
In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments in vitro . The domestic research started late, and the corresponding testing methods were lacking. There is still no unified standard. In this paper, a complete hardware test system was designed and built around the existing mechanical testing machine, including:binocular vision catcher, torque bearing clamp, film pressure sensor and so on...
July 30, 2018: Zhongguo Yi Liao Qi Xie za Zhi, Chinese Journal of Medical Instrumentation
Otavio Andre Chase, Mailson Borges Teles, Marinaldo de Jesus Dos Santos Rodrigues, José Felipe Souza de Almeida, Wilson Negrão Macêdo, Carlos Tavares da Costa Junior
In this paper, we present a low-cost, stand-alone sensory platform developed for in situ monitoring of environmental parameters, for use in the Amazon region in the north of Brazil. The mission of the platform is to perform monitoring and identification of overirradiance (solar irradiance > 1000 W/m²) and extreme overirradiance events (solar irradiance > 1300 W/m²) using a photovoltaic based irradiance sensor. The sensory platform was built using the ESP8266 microcontroller, an open embedded computer capable of Wi-Fi communication using the IEEE 802...
August 15, 2018: Sensors
Chen Li, Boshan Sun, Yanan Xue, Jijun Xiong
Alumina ceramic is a highly promising material for fabricating high-temperature pressure sensors. In this paper, a direct bonding method for fabricating a sensitive cavity with alumina ceramic is presented. Alumina ceramic substrates were bonded together to form a sensitive cavity for high-temperature pressure environments. The device can sense pressure parameters at high temperatures. To verify the sensitivity performance of the fabrication method in high-temperature environments, an inductor and capacitor were integrated on the ceramic substrate with the fabricated sensitive cavity to form a wireless passive LC pressure sensor with thick-film integrated technology...
August 14, 2018: Sensors
Jae Woong Yoon, Jin Tae Kim, Bong Je Park, Sungryul Yun, Seongcheol Mun, Seung Koo Park, Suntak Park
We propose an elastomer thin-film pressure sensor enabled by pressure-sensitive optical signals through vertical photonic tunnel-junction couplers. We provide the operation principle, design, fabrication, and test results from a 50 μm thick polydimethylsiloxane sheet accommodating embedded vertical photonic tunnel-junction couplers. The result with a 5 mm long device shows a differential optical power change that is ∼140% of the incident power under moderate external pressure of ∼40  kPa, thereby clearly demonstrating a robust pressure-sensing capability realized in a highly flexible, lightweight, transferrable, optically transparent, and bio-compatible thin-film material...
August 15, 2018: Optics Letters
Wenbo Li, Jiangjiang Duan, Junwen Zhong, Nan Wu, Shizhe Lin, Zisheng Xu, Shuwen Chen, Yuan Pan, Liang Huang, Bin Hu, Jun Zhou
Flexible pressure sensors possess promising applications in artificial electronic skin (e-skin), intelligence robot, wearable health monitoring, flexible physiological signal sensing, etc. Herein, we design a flexible pressure sensor with robust stability, high sensitivity and large linear pressure region based on tetrafluoroethylene-hexafluoropropylene-vinylide (THV) / cyclic olefin copolymer (COC) piezoelectret nanogenerator. According to the theoretical analysis for piezoelectret nanogenerators with imbalanced charge distribution, THV and COC are utilized to promote the electric field inside the piezoelectret for output voltage enhancement...
August 14, 2018: ACS Applied Materials & Interfaces
Jie Liu, Teh Lin, Jiajin Fan, Lili Chen, Robert Price, C-M Charlie Ma
PURPOSE: Two different respiratory monitoring systems (Varian's Real-Time Position Management (RPM) System and Siemens' ANZAI belt Respiratory Gating System) are compared in the context of respiratory signals and 4D CT images that are accordingly reconstructed. This study aims to evaluate the feasibility of combined use of RPM and ANZAI systems for 4DCT simulation and gated radiotherapy treatment, respectively. METHODS: The RPM infrared reflecting marker and the ANZAI belt pressure sensor were both placed on the patient's abdomen during 4DCT scans...
August 13, 2018: Journal of Applied Clinical Medical Physics
Sangmin An, Bongsu Kim, Soyoung Kwon, Geol Moon, Manhee Lee, Wonho Jhe
Mechanical sensors provide core keys for high-end research in quantitative understanding of fundamental phenomena and practical applications such as the force or pressure sensor, accelerometer and gyroscope. In particular, in situ sensitive and reliable detection is essential for measurements of the mechanical vibration and displacement forces in inertial sensors or seismometers. However, enhancing sensitivity, reducing response time and equipping sensors with a measurement capability of bidirectional mechanical perturbations remains challenging...
August 11, 2018: Sensors
Victoire M C Rérolle, Eric P Achterberg, Mariana Ribas-Ribas, Vassilis Kitidis, Ian Brown, Dorothee C E Bakker, Gareth A Lee, Matthew C Mowlem
Increasing atmospheric CO₂ concentrations are resulting in a reduction in seawater pH, with potential detrimental consequences for marine organisms. Improved efforts are required to monitor the anthropogenically driven pH decrease in the context of natural pH variations. We present here a high resolution surface water pH data set obtained in summer 2011 in North West European Shelf Seas. The aim of our paper is to demonstrate the successful deployment of the pH sensor, and discuss the carbonate chemistry dynamics of surface waters of Northwest European Shelf Seas using pH and ancillary data...
August 10, 2018: Sensors
Xiaoxiong Wang, Wei-Zhi Song, Ming-Hao You, Jun Zhang, Miao Yu, Zhiyong Fan, Seeram Ramakrishna, Yun-Ze Long
Moravec's paradox shows that low-level sensorimotor skills are more difficult than high-level reasoning in artificial intelligence and robotics area. So simplifying every sensing unit on electronic skin is critical for endowing intelligent robots with tactile and temperature sense. The human nervous system is characterized by efficient single-electrode signal transmission, ensuring the efficiency and reliability of information transmission under big data conditions. In this work, we report a sensor based on single-electrode piezoelectric nanogenerator (SPENG) by electrospun polyvinylidene fluoride(PVDF) nanofibers that can realize steady state sensing of pressure integrating cold/heat sensing on a single unit...
August 13, 2018: ACS Nano
Andreas Lorek, Jacek Majewski
In experimental chambers for simulating the atmospheric near-surface conditions of Mars, or in situ measurements on Mars, the measurement of the humidity in carbon dioxide gas at low temperature and under low pressure is needed. For this purpose, polymer-based capacitive humidity sensors are used; however, these sensors are designed for measuring the humidity in the air on the Earth. The manufacturers provide only the generic calibration equation for standard environmental conditions in air, and temperature corrections of humidity signal...
August 9, 2018: Sensors
Sang Eon Lee, Peipei Liu, Young Woo Ko, Hoon Sohn, Byeongjin Park, Jung-Wuk Hong
In this paper, the effect of ablation on the shape of elastic waves generated by laser excitation is studied numerically and experimentally. Laser-induced ultrasound has been widely used in the nondestructive testing (NDT) field because it has the advantage that the sensor does not have to be directly attached to the target structure. In the safety assessment process, low energy excitation is used, and thus the structure is not damaged. Most studies related to laser ultrasound have focused on the method of detecting cracks within the elastic range, and there have been few studies on the effect of ablation...
July 29, 2018: Ultrasonics
N Khalili, X Shen, H E Naguib
The development of flexible pressure sensors with human-like sensing capabilities is an emerging field due to their wide range of applications from human robot interactions to wearable electronics. Piezoresistive sensors respond to externally induced mechanical stimuli through changes in their electrical resistance. The current state-of-the-art piezoresistive sensors are mainly constructed via dispersion of conductive nanofillers in an elastomer matrix making their performance strongly reliable on the degree of dispersion...
August 10, 2018: Soft Matter
Wenlang Li, Qiuyi Huang, Zhu Mao, Qi Li, Long Jiang, Zongliang Xie, Rui Xu, Zhiyong Yang, Juan Zhao, Tao Yu, Yi Zhang, Matthew P Aldred, Zhenguo Chi
Mechanoluminescence (ML) materials are environmentally friendly and emit light by utilizing mechanical energy, which have been utilized in light source, display, bioimaging and advanced sensors. Organic ML materials have attracted much attention because of convenient synthesis and various ML properties. However, they are strongly limited to application by in-situ unrepeatable ML. Here, a novel strategy of in-situ solar-renewable organic ML materials was shown, by introducing "soft" alkyl chain into an ML unit...
August 9, 2018: Angewandte Chemie
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