scholarly journals Bacterial Concentration Detection using a PCB-based Contactless Conductivity Sensor

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 55 ◽  
Author(s):  
Xiao-Yan Zhang ◽  
Zhe-Yu Li ◽  
Yu Zhang ◽  
Xiao-Qian Zang ◽  
Kosei Ueno ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Printed Circuit Board ◽  
System Size ◽  
Circuit Board ◽  
Plate Count ◽  
Capacitively Coupled ◽  
Conductivity Sensor ◽  
Relative Standard ◽  
In Situ Detection

Capacitively coupled contactless conductivity detection (C4D) is an improved approach to avoid the problems of labor-intensive, time-consuming and insufficient accuracy of plate count as well as the high-cost apparatus of flow cytometry (FCM) in bacterial counting. This article describes a novel electrode-integrated printed-circuit-board (PCB)-based C4D device, which supports the simple and safe exchange of capillaries and improves the sensitivity and repeatability of the contactless detection. Furthermore, no syringe pump is needed in the detection, it reduces the system size, and, more importantly, avoids the effect on the bacteria due to high pressure. The recovered bacteria after C4D detection at excitation of 25 Vpp and 60–120 kHz were analyzed by flow cytometry, and a survival rate higher than 96% was given. It was verified that C4D detection did not influence the bacterial viability. Moreover, bacteria concentrations from 106 cells/mL to 108 cells/mL were measured in a linear range, and relative standard deviation (RSD) is below 0.2%. In addition, the effects on bacteria and C4D from background solutions were discussed. In contrast to common methods used in most laboratories, this method may provide a simple solution to in situ detection of bacterial cultures.

In-Situ Mechanical Sample Preparation of Selected Sites and Components on Large Modules and Boards

2016 ◽  
Author(s):  
Jim Colvin ◽  
Timothy Hazeldine ◽  
Heenal Patel
Keyword(s):  
Sample Preparation ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Tilt Table ◽  
Standard Requirement ◽  
Open Design ◽  
Bga Packages ◽  
Silicon Thickness ◽  
Board Level

Abstract The standard requirement for FA Engineers needing to remove components from a board, prior to decapsulation or sample preparation, is shown to be greatly reduced, by the methods discussed here. By using a mechanical selected area preparation system with an open-design it is possible to reach all required areas of a large printed circuit board (PCB) or module to prepare a single component ‘in situ’. This makes subsequent optical or electrical testing faster and often more convenient to accomplish. Electronic End-pointing and 3D curvature compensation methods can often be used in parallel with sample prep techniques to further improve the consistency and efficacy of the decapsulation and thinning uniformity and final remaining silicon thickness (RST). Board level prep eliminates the worry of rework removal of BGA packages and the subsequent risk of damage to the device. Since the entire board is mounted, the contamination is restricted to the die surface and can be kept from the underside ball connections unlike current liquid immersion methods of package thinning or delayering. Since the camera is in line with the abrasion interface, imaging is real time during the entire milling and thinning process. Recent advances in automated tilt-table design have meant that a specific component’s angular orientation can be optimized for sample preparation. Improved tilt table technology also allows for improved mounting capability for boards of many types and sizes. The paper describes methods for decapsulation, thinning and backside polishing of a part ‘in situ’ on the polishing machine and allows the system to operate as a probe station for monitoring electrical characteristics while thinning. Considerations for designing board-level workholders are described – for boards that that are populated with components on one or even both sides. Using the techniques described, the quality of sample preparation and control is on a par with the processing of single package-level devices.

scholarly journals Capturing Electrocardiogram Signals from Chairs by Multiple Capacitively Coupled Unipolar Electrodes

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2835 ◽  
Author(s):  
Zhongjie Hou ◽  
Jinxi Xiang ◽  
Yonggui Dong ◽  
Xiaohui Xue ◽  
Hao Xiong ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Experimental Tests ◽  
Circuit Board ◽  
Signal Acquisition ◽  
Ecg Signal ◽  
Capacitively Coupled ◽  
Ecg Signals ◽  
Printed Circuit ◽  
Electrocardiogram Signals ◽  
Electrocardiogram Ecg

A prototype of an electrocardiogram (ECG) signal acquisition system with multiple unipolar capacitively coupled electrodes is designed and experimentally tested. Capacitively coupled electrodes made of a standard printed circuit board (PCB) are used as the sensing electrodes. Different from the conventional measurement schematics, where one single lead ECG signal is acquired from a pair of sensing electrodes, the sensing electrodes in our approaches operate in a unipolar mode, i.e., the biopotential signals picked up by each sensing electrodes are amplified and sampled separately. Four unipolar electrodes are mounted on the backrest of a regular chair and therefore four channel of signals containing ECG information are sampled and processed. It is found that the qualities of ECG signal contained in the four channel are different from each other. In order to pick up the ECG signal, an index for quality evaluation, as well as for aggregation of multiple signals, is proposed based on phase space reconstruction. Experimental tests are carried out while subjects sitting on the chair and clothed. The results indicate that the ECG signals can be reliably obtained in such a unipolar way.

Kinetic study of mitochondria in erythropoiesis of anemized amphibians, applying rhodamine 123, flow cytometry and in situ detection of oxidation-reduction enzymes

1992 ◽  
Vol 50 (1) ◽  
pp. 926-927
Author(s):  
Aurora Marques Cianciarullo ◽  
Álvaro Luiz Bertho ◽  
Maria de Nazareth ◽  
Leal de Meirellesu
Keyword(s):  
Flow Cytometry ◽  
Kinetic Study ◽  
Beta Globin ◽  
Hormonal Stimulation ◽  
Heme Synthesis ◽  
Globin Chains ◽  
Iron Supply ◽  
Oxidation Reduction ◽  
In Situ Detection

Amphibians erythropoiesis is similar to that of vertebrates in general, comprising: (1) an erythropoietin hormonal stimulation, for differentiation, (2) a lineage of pre cursor maturing cells, (3) alfa and beta globin chains synthesis, (4) an adequate iron supply for heme synthesis, followed by (5) the final hemoglobin (Hb) biosynthesis. Several studies try to establish a correlation between mitochondria and heme synthesis, and the final Hb biosynthesis.

A PCB Technology Moisture Content and Electrical Conductivity Sensor Probe for Agricultural and Horticultural Applications

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 000984-001011
Author(s):  
Robert N. Dean ◽  
Elizabeth Guertal ◽  
Adam Newby ◽  
Glenn Fain
Keyword(s):  
Electrical Conductivity ◽  
Plant Growth ◽  
Moisture Content ◽  
Test Data ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Conductivity Sensor ◽  
Irrigation Volume ◽  
Sensor Probe

Commercial printed circuit board (PCB) technology affords the realization of low-cost sensor probes for agricultural and horticultural applications. Plant growth can be optimized when the soil (in field crop applications) or the substrate (in greenhouse crop applications) properties can be measured and properly adjusted. Two important parameters are moisture content and electrical conductivity. Measuring moisture content allows the grower to better time irrigation for most efficient crop growth. Accurate moisture content measurement also allows the grower to apply sufficient irrigation volume for optimum plant growth while avoiding excessive irrigation volume. Likewise, measuring the electrical conductivity reveals useful information regarding ions in the soil or substrate, which can be used to optimize the application of plant nutrients or manage soil salinity. Commercial soil probes are expensive, which limits their widespread use in commercial applications. PCB probes, on the other hand, can be very inexpensive and can quickly be redesigned to modify the form factor for different applications. These sensors make use of the materials and processes inherent in commercial PCB manufacturing, including the FR4 substrate, patterned Cu cladding and soldermask. The non-conductive E-glass FR4 substrate is used as the rigid backbone of the sensor probe. The patterned Cu cladding is used for electrodes and signal traces. The polymeric soldermask is used as a thin insulating and moisture barrier layer. With these materials, insulated fringing field sensors can be realized on the surface of the PCB to measure moisture content, while exposed metal pads on the surface can be used to measure electrical conductivity. Additionally, the PCB probe is directly compatible with the integration of any desired integrated electronic components. Furthermore, the turnaround time for a new PCB sensor design can be as little as 24 hours at modest cost, making this technology economically superior to traditional sensor technologies, such as silicon based MEMS, where it can take months to realize a new design and be very expensive. A prototype sensor probe has been designed, fabricated and evaluated. Test data is analyzed, compared with test data from traditional sensor probes and presented.

scholarly journals Laser-Induced Silver Seeding on Filter Paper for Selective Electroless Copper Plating

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1348 ◽  
Author(s):  
Chang-Chun Liu ◽  
Jin Cheng ◽  
Xiao-Qiang Li ◽  
Zhi-Jie Gu ◽  
Kenji Ogino
Keyword(s):  
Composite Film ◽  
Filter Paper ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Silver Particles ◽  
Electroless Copper Plating ◽  
Ag Particles ◽  
Flexible Printed Circuit ◽  
Irradiation Technology

The generation of a flexible printed circuit board on polymer fabrics has been a challenge over the last decade. In this work, a copper pattern was obtained on a soft substrate of filter paper/polyacrylonitrile (FP/PAN) film, where the filter paper was commercially available. The pattern of Ag particles was first produced on an Ag+-doped FP/PAN composite film, followed by electroless plating of copper using the metal silver particles as seeds. The in situ reduction of silver particles and the formation of the silver agglomeration pattern were induced by laser irradiation technology on the FP/PAN/AgNO3 composite film. A variety of characterizations indicated that the resultant copper deposition was uniform, with good conductivity properties.

Validation of Electronic Package Reliability Using Speckle Interferometry

2002 ◽  
Vol 124 (3) ◽  
pp. 277-280 ◽  
Author(s):  
H.-Y. Yeh ◽  
K. Cote
Keyword(s):  
Thermal Loading ◽  
Printed Circuit Board ◽  
Coefficient Of Thermal Expansion ◽  
Speckle Interferometry ◽  
Circuit Board ◽  
Half Cycle ◽  
Electronic Packages ◽  
Snpb Solder ◽  
Shear Strains

In-situ measurements were performed on organic based substrates under mechanical loading as well as land grid array electronic packages under thermal cycling. Whole field displacement measurements obtained from this analysis were compared with results obtained from similar finite element models. The experimental flexibility and results obtained from speckle interferometry indicate that this method has several substantial benefits over moire´ interferometry. Due to coefficient of thermal expansion mismatches between the package and printed circuit board, creep shear strains developed in the 63/37 SnPb solder. When thermally loaded, these creep shear strains develop cracks in the joint leading to Mode II failure. A single thermal half cycle from 25°C to 125°C was applied to a specimen to simulate the fatigue life of the solder joints undergoing thermal loading and the resulting strains were entered into the Engelmaier reliability prediction model for 63/37 SnPb solder. The experimental results yielded 0.59% strain per cycle with 7485 cycles to failure.

In situ Decapsulation of Plastic Encapsulated Devices Mounted to a Printed Circuit Board

2002 ◽  
Author(s):  
Ronald R. Hylton
Keyword(s):  
Printed Circuit Board ◽  
Failure Mechanisms ◽  
Circuit Board ◽  
Printed Circuit ◽  
Board Material

Abstract In situ decapsulation of plastic devices can be used to avoid the removal or alteration of failure mechanisms caused by exposure to desoldering temperatures. This paper describes techniques to decapsulate devices mounted to a printed circuit board using materials that are readily available and easily customized to specific applications. The techniques are extended to the decapsulation of other packaging technologies, such as SBGA packages and chip-on-board assemblies. Finally, post decapsulation cleaning techniques that will not harm the printed circuit board material are presented.

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