scholarly journals Refinement of the method for selecting the width of the conductor of printed circuit boards on a metal base, working in the absence of convection

2021 ◽  
Vol 24 (3) ◽  
pp. 80-91
Author(s):  
Aleksey V. Kostin
Keyword(s):  
Printed Circuit Boards ◽  
Sufficient Accuracy ◽  
Logarithmic Scale ◽  
Graphical Methods ◽  
Conductive Heat ◽  
Circuit Boards ◽  
Metal Base ◽  
Printed Circuit ◽  
Refined Method

The article proposes a refined method for calculating the width of the conductors of printed circuit boards on a metal base for the onboard devices of spacecraft, depending on the current flowing. The constructed refined mathematical model of the process of conductive heat exchange between the conductors and the metal base is described. The results of calculations of various, most common, locations of layers of printed circuit boards are presented. An analysis was carried out and a refined methodology was developed based on the results obtained. It allows you to easily (without complicate calculations) calculate the necessary values of the width of conductors. This technique is based on graphical methods, but allows you to perform technical calculations with sufficient accuracy. Accuracy is achieved by using special formulas that simplify the determination of the value of a physical quantity on a logarithmic scale. The disadvantages of the proposed method are indicated.

Development of a versatile analytical protocol for the comprehensive determination of the elemental composition of smartphone compartments on the example of printed circuit boards

2018 ◽  
Vol 10 (31) ◽  
pp. 3864-3871 ◽  
Author(s):  
B. Bookhagen ◽  
W. Obermaier ◽  
C. Opper ◽  
C. Koeberl ◽  
T. Hofmann ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Printed Circuit Boards ◽  
Electronic Devices ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Comprehensive Method ◽  
Analytical Protocol ◽  
Comprehensive Determination

A comprehensive method for the determination of metals in electronic devices was developed and tested on smartphones.

Determination of Elemental Content in Solder Mask Samples Used in Printed Circuit Boards Using Different Spectroanalytical Techniques

2018 ◽  
Vol 72 (8) ◽  
pp. 1205-1214 ◽  
Author(s):  
Marco Aurelio Sperança ◽  
Alex Virgilio ◽  
Edenir Rodrigues Pereira-Filho ◽  
Francisco Wendel Batista de Aquino
Keyword(s):  
Inductively Coupled Plasma ◽  
Printed Circuit Boards ◽  
Hazardous Substances ◽  
Emission Spectrometry ◽  
Elemental Content ◽  
The European Union ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Inductively Coupled

Solder masks are essential materials used in the manufacture of printed circuit boards (PCB). This material protects PCBs against several types of damage and performance failure. In this study, the capabilities of laser-induced breakdown spectroscopy (LIBS) were investigated for the direct analysis of solder masks typically commercialized for homemade PCB production, and inductively coupled plasma–optical emission spectrometry (ICP-OES) was used to obtain a chemical profile for the target analytes Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Sb, Sn, and Zn. Inductively coupled plasma–mass spectrometry (ICP-MS) was also employed for the determination of potentially toxic elements, such as As, Cd, Cr, Pb, and Hg. In addition to the qualitative information that may be useful for obtaining the spectral profile related to the raw materials present in solder masks formulations, LIBS was also applied for major elements (Al, Ba, Cu, Fe, Mg, and Zn) determination, but due to the low sensitivity, the obtained results were only semi-quantitative for Ba. Regarding Cd, Cr, Hg, and Pb, the samples analyzed were following the restriction of hazardous substances (RoHS) directive of the European Union.

scholarly journals Synthesis, characterization, and crystal structure of aquabis(4,4′-dimethoxy-2,2′-bipyridine)[μ-(2R,3R)-tartrato(4−)]dicopper(II) octahydrate

2019 ◽  
Vol 75 (7) ◽  
pp. 972-975
Author(s):  
Dennis Wiedemann ◽  
Roman-David Kulko ◽  
Andreas Grohmann
Keyword(s):  
Crystal Structure ◽  
Printed Circuit Boards ◽  
Ex Situ ◽  
Complexing Agent ◽  
Circuit Boards ◽  
Complex Molecules ◽  
Synthesis And Crystal Structure ◽  
Printed Circuit ◽  
Absolute Structure

Typical electroless copper baths (ECBs), which are used to chemically deposit copper on printed circuit boards, consist of an aqueous alkali hydroxide solution, a copper(II) salt, formaldehyde as reducing agent, an L-(+)-tartrate as complexing agent, and a 2,2′-bipyridine derivative as stabilizer. Actual speciation and reactivity are, however, largely unknown. Herein, we report on the synthesis and crystal structure of aqua-1κO-bis(4,4′-dimethoxy-2,2′-bipyridine)-1κ2 N,N′;2κ2 N,N′-[μ-(2R,3R)-2,3-dioxidosuccinato-1κ2 O 1,O 2:2κ2 O 3,O 4]dicopper(II) octahydrate, [Cu2(C12H12N2O2)2(C4H2O6)(H2O)]·8H2O, from an ECB mock-up. The title compound crystallizes in the Sohncke group P21 with one chiral dinuclear complex and eight molecules of hydrate water in the asymmetric unit. The expected retention of the tartrato ligand's absolute configuration was confirmed via determination of the absolute structure. The complex molecules exhibit an ansa-like structure with two planar, nearly parallel bipyridine ligands, each bound to a copper atom that is connected to the other by a bridging tartrato `handle'. The complex and water molecules give rise to a layered supramolecular structure dominated by alternating π stacks and hydrogen bonds. The understanding of structures ex situ is a first step on the way to prolonged stability and improved coating behavior of ECBs.

Determination of Time-Sharing Efficiency in an Industrial Visual Inspection Task

1986 ◽  
Vol 30 (5) ◽  
pp. 461-465
Author(s):  
David C. Gibson ◽  
Joseph H. Goldberg
Keyword(s):  
Secondary Task ◽  
Visual Inspection ◽  
Printed Circuit Boards ◽  
Mental Workload ◽  
Time Sharing ◽  
Circuit Boards ◽  
Pilot Experiment ◽  
Printed Circuit ◽  
Inspection Task

This pilot experiment examined two variations of a secondary task used in determining the time-sharing ability of an inspector searching for defects on printed circuit boards. The methodology incorporated mathematical PRF and POC models, revealing that greater efficiencies were achieved with the easier secondary task. The inspection task was determined to be data-limited. Results will be used in the design of a mental workload study in visual inspection.

scholarly journals Determination of Metals’ Content in Components Mounted on Printed Circuit Boards from End-of-Life Mobile Phones

Recycling ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 20
Author(s):  
Tadeusz Gorewoda ◽  
Marcus Eschen ◽  
Jadwiga Charasińska ◽  
Magdalena Knapik ◽  
Sylwia Kozłowicz ◽  
...  
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Raw Materials ◽  
Absorption Spectrometry ◽  
Atomic Emission ◽  
Emission Spectrometry ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Valuable Metals

The electronic components mounted on the printed circuit boards (PCBs) of mobile phones represent a resource that is rich in metals, and after separation from the boards, these components could be considered secondary raw materials. The concentrations of the valuable metals are insignificant when compared with those of complete PCBs; however, they could be significantly higher in a fraction formed from the separated components. This study focused on the analysis of Ag, Au, Cu, Nd, Nb, Ni, Pb, Pd, Sn, and Ta in fractions produced by the separation of all the components mounted on PCBs from several types of mobile phones. Atomic absorption spectrometry, atomic emission spectrometry, and mass spectrometry techniques were utilized, and a comparison of five older models of “brick” phones and five modern smartphones was conducted. Additionally, 50 kg of PCBs from the current recycling market were analyzed in the same way to create a summary of the current recycling stream.

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