Effect of Standoff on Near-Field Blast Mitigation Provided by Water-Filled Containers

2019 ◽  
Vol 86 (7) ◽  
Author(s):  
Huon Bornstein ◽  
Sam Di Placido ◽  
Shannon Ryan ◽  
Adrian C. Orifici ◽  
Adrian P. Mouritz
Keyword(s):  
Simple Technique ◽  
Experimental Testing ◽  
Low Cost ◽  
Near Field ◽  
Blast Mitigation ◽  
Target Plate ◽  
Blast Protection ◽  
Steel Target ◽  
Blast Effects ◽  
Armored Vehicle

Water-filled containers placed externally on an armored vehicle offer a potentially low cost, light-weight, and simple technique to mitigate near-field explosive blast, although the use of a gap or standoff between the container and target has not been studied. This paper uses experimental testing and numerical simulations to characterize the influence of this container standoff on the mitigation of near-field blast effects. The addition of the container standoff was not found to generally increase the blast mitigation effect provided by water-filled containers on the deformation caused to a steel target plate. While the container standoff was found to enhance the spreading and shadowing blast mitigation mechanisms provided by the water-filled container, this was offset by an increase in blast loading due to the container being closer to the explosive charge. A new mitigation mechanism was identified as the time delay between the initial loading of the steel plate by the blast wave and the subsequent impact of water ejected from the container. The results from this work provide engineers guidance into the design of water-filled containers for near-field blast protection of armored vehicles.

scholarly journals A Lab-Scale Experiment Approach to the Measurement of Wall Pressure from Near-Field under Water Explosions by a Hopkinson Bar

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xiongwei Cui ◽  
Xiongliang Yao ◽  
Yingyu Chen
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Underwater Explosion ◽  
Experimental System ◽  
Hopkinson Bar ◽  
Wall Pressure ◽  
Pressure Loading ◽  
Target Plate ◽  
Wave Pressure ◽  
Shock Wave Pressure

Direct measurement of the wall pressure loading subjected to the near-field underwater explosion is of great difficulty. In this article, an improved methodology and a lab-scale experimental system are proposed and manufactured to assess the wall pressure loading. In the methodology, a Hopkinson bar (HPB), used as the sensing element, is inserted through the hole drilled on the target plate and the bar’s end face lies flush with the loaded face of the target plate to detect and record the pressure loading. Furthermore, two improvements have been made on this methodology to measure the wall pressure loading from a near-field underwater explosion. The first one is some waterproof units added to make it suitable for the underwater environment. The second one is a hard rubber cylinder placed at the distal end, and a pair of ropes taped on the HPB is used to pull the HPB against the cylinder hard to ensure the HPB’s end face flushes with loaded face of the target plate during the bubble collapse. To validate the pressure measurement technique based on the HPB, an underwater explosion between two parallelly mounted circular target plates is used as the validating system. Based on the assumption that the shock wave pressure profiles at the two points on the two plates which are symmetrical to each other about the middle plane of symmetry are the same, it was found that the pressure obtained by the HPB was in excellent agreement with pressure transducer measurements, thus validating the proposed technique. To verify the capability of this improved methodology and experimental system, a series of minicharge underwater explosion experiments are conducted. From the recorded pressure-time profiles coupled with the underwater explosion evolution images captured by the HSV camera, the shock wave pressure loading and bubble-jet pressure loadings are captured in detail at 5  mm, 10  mm, …, 30  mm stand-off distances. Part of the pressure loading of the experiment at 35  mm stand-off distance is recorded, which is still of great help and significance for engineers. Especially, the peak pressure of the shock wave is captured.

Determination of Ultrasonic Welding Optimal Parameters for Thermoplastic Material of Manufacturing Products

2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Rashiqah Rashli ◽  
Elmi Abu Bakar ◽  
Shahrul Kamaruddin
Keyword(s):  
Electronic Device ◽  
Low Cost ◽  
Near Field ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Field Configuration ◽  
Welding Parameters ◽  
Optimal Parameters ◽  
Thermoplastic Material

Ultrasonic welding had been widely used in various manufacturing industries such as aviation, medical, electronic device and many more. It offers a continued safe operation, faster and also low cost as it able to join weld part less than one second and also simple to maintain the tooling devices. Though ultrasonic welding brings a lot of advantages in assembly especially in thermoplastic material of manufacturing product, it also has a dominant problem to be deal with. The problem in ultrasonic welding is poor weld quality due to improper selection of ultrasonic welding parameters especially in near field configuration. Thus, an optimal combination of parameters is crucial in order to produce good quality weld assembly for this configuration. In this paper, ultrasonic welding process, ultrasonic weld joint defects and determination of optimal parameters for thermoplastic material had been discussed thoroughly. 

scholarly journals A Survey of NFC Sensors Based on Energy Harvesting for IoT Applications

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3746 ◽  
Author(s):  
Antonio Lazaro ◽  
Ramon Villarino ◽  
David Girbau
Keyword(s):  
Energy Harvesting ◽  
Integrated Circuits ◽  
Radio Frequency Identification ◽  
Low Cost ◽  
Near Field ◽  
Wearable Sensors ◽  
Cold Chain ◽  
Iot Applications ◽  
Wide Range ◽  
Frequency Identification

In this article, an overview of recent advances in the field of battery-less near-field communication (NFC) sensors is provided, along with a brief comparison of other short-range radio-frequency identification (RFID) technologies. After reviewing power transfer using NFC, recommendations are made for the practical design of NFC-based tags and NFC readers. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. Finally, a survey of the state of the art in NFC-based sensors is presented, which demonstrates that a wide range of sensors (both chemical and physical) can be used with this technology. Particular interest arose in wearable sensors and cold-chain traceability applications. The availability of low-cost devices and the incorporation of NFC readers into most current mobile phones make NFC technology key to the development of green Internet of Things (IoT) applications.

Fabrication of Low Cost 1D CdSe Nanowires using Near-field Electrospinning

2011 ◽  
Vol 1302 ◽  
Author(s):  
Leroy Magwood ◽  
Binil Starly
Keyword(s):  
Quantum Dots ◽  
Fluorescence Microscopy ◽  
Fiber Diameter ◽  
Low Cost ◽  
Near Field ◽  
Light Attenuation ◽  
Dimethyl Formamide ◽  
Cdse Quantum Dot ◽  
The Matrix ◽  
Cdse Nanowires

ABSTRACTWell-aligned, 1D CdSe quantum dot (QD) fibers (0.3μm to 2.5μm) containing up to 20wt% fluorescent quantum dots (QDs) were prepared by near-field electrospinning (NFES) process. Electrospun solutions were prepared using PVAc as the matrix polymer, dimethyl formamide (DMF) solvent and colloidal QDs in chloroform (CHCl3). The diameter of the fibers decreased as the ratio of DMF/CHCl3 is varied. QDs showed good dispersion and a linear relationship between QD loading and fiber diameter, as determined by the morphology measurements taken using TEM and SEM, respectively. Fluorescence microscopy shows that there is light attenuation throughout the fibers. Results also show that the NFES process may be used as a method to create aligned, 1D fibers of QDs and potentially other nanofibers.

Unraveling near-field and far-field relationships for 3D SERS substrates – a combined experimental and theoretical analysis

The Analyst ◽  
2016 ◽  
Vol 141 (5) ◽  
pp. 1779-1788 ◽  
Author(s):  
Dmitry Kurouski ◽  
Nicolas Large ◽  
Naihao Chiang ◽  
Nathan Greeneltch ◽  
Keith T. Carron ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Low Cost ◽  
Near Field ◽  
Far Field ◽  
Sers Substrates

Simplicity and low cost has positioned inkjet 3D substrates as the most commonly used SERS platforms for the detection and the identification of analytes down to the nanogram and femtogram levels.

Numerical Analysis of Shockwave Propagation in Urban Underpass

2012 ◽  
Vol 13 (2) ◽  
pp. 201-207
Author(s):  
Xin Li ◽  
Zhihua Wang ◽  
Guiying Wu
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Traffic Congestion ◽  
Traffic Accidents ◽  
Peak Pressure ◽  
Near Field ◽  
Horizontal Direction ◽  
Pressure Distributions ◽  
Blast Effects ◽  
Potential Damage

Abstract As an indispensable part of transportation system, urban underpass can alleviate traffic congestion and reduce traffic accidents effectively. In order to acquaint the hydrodynamics of shockwave in underpass and assess the potential damage and risk of bombing accidents, a numerical simulation was established to calculate the blast effects originating from the 13Kg TNT. Based on the location of detonation point, the shape of corridor section and the exit's cover, peak pressure distributions were predicted. The results indicate that the propagation of shockwave in horizontal direction switches to the inclined top of ground in a near-field due to the ground reflection and the set of exit's cover increases the risk of explosion to the structure and the users.

scholarly journals Near-Field Communication Sensors

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3947 ◽  
Author(s):  
Zhonglin Cao ◽  
Ping Chen ◽  
Zhong Ma ◽  
Sheng Li ◽  
Xingxun Gao ◽  
...  
Keyword(s):  
Communication Technology ◽  
Low Cost ◽  
Near Field ◽  
Near Field Communication ◽  
Daily Life Activities ◽  
Quality Detection ◽  
Communication Device ◽  
Real World Applications ◽  
Wireless Signal ◽  
Communication Devices

Near-field communication is a new kind of low-cost wireless communication technology developed in recent years, which brings great convenience to daily life activities such as medical care, food quality detection, and commerce. The integration of near-field communication devices and sensors exhibits great potential for these real-world applications by endowing sensors with new features of powerless and wireless signal transferring and conferring near field communication device with sensing function. In this review, we summarize recent progress in near field communication sensors, including the development of materials and device design and their applications in wearable personal healthcare devices. The opportunities and challenges in near-field communication sensors are discussed in the end.

Integrated Bidirectional Inductive-Array Design for Power Transfer in Implantable BioMEMS

Proceedings ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 10 ◽  
Author(s):  
Natiely Hernández-Sebastián ◽  
Francisco Javier Renero-Carrillo ◽  
Daniela Díaz-Alonso ◽  
Wilfrido Calleja-Arriaga
Keyword(s):  
Continuous Monitoring ◽  
Electromagnetic Coupling ◽  
Low Cost ◽  
Near Field ◽  
Power Transfer ◽  
Inductive Power Transfer ◽  
Thin Film Fabrication ◽  
Novel Approach ◽  
Power Transfer Efficiency ◽  
Novel Design

This work presents a novel design of a bidirectional Inductive Power Transfer (IPT) system capable of continuous monitoring of cardiac pressure. The proposed system results from a robust electromagnetic coupling between an external reading coil and an implanted two-level (3D approach) inductor array. In this design, each coupling module follows a 13.56 MHz operating frequency, where both passive RCL networks are near field tuned. Among our main results, we obtained a Power Transfer Efficiency (PTE) of 94.1% across the 3.5 cm-thick composed biological tissue whereas the implanted coil array is about 50% of its conventional size. Since the resulting PTE efficiency is 40% higher, based on the optimized L and Q parameters, this novel approach could be used in other medical applications. This IPT system design is based on a low-cost thin film fabrication technology.

scholarly journals Color Measurement and Analysis of Fruit with a Battery-Less NFC Sensor

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1741 ◽  
Author(s):  
Antonio Lazaro ◽  
Marti Boada ◽  
Ramon Villarino ◽  
David Girbau
Keyword(s):  
Low Cost ◽  
Near Field ◽  
Color Space ◽  
Cloud Service ◽  
Color Measurement ◽  
Classification Algorithms ◽  
Measurement And Analysis ◽  
Hue Angle ◽  
Color Data ◽  
The Magnetic Field

This paper presents a color-based classification system for grading the ripeness of fruit using a battery-less Near Field Communication (NFC) tag. The tag consists of a color sensor connected to a low-power microcontroller that is connected to an NFC chip. The tag is powered by the energy harvested from the magnetic field generated by a commercial smartphone used as a reader. The raw RGB color data measured by the colorimeter is converted to HSV (hue, saturation, value) color space. The hue angle and saturation are used as features for classification. Different classification algorithms are compared for classifying the ripeness of different fruits in order to show the robustness of the system. The low cost of NFC chips means that tags with sensing capability can be manufactured economically. In addition, nowadays, most commercial smartphones have NFC capability and thus a specific reader is not necessary. The measurement of different samples obtained on different days is used to train the classification algorithms. The results of training the classifiers have been saved to the cloud. A mobile application has been developed for the prediction based on a table-based method, where the boundary decision is downloaded from a cloud service for each product. High accuracy, between 80 and 93%, is obtained depending on the kind of fruit and the algorithm used.

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