Polycarbonate Base Research Articles

Research of the plasticizing binder type and quantity influence on the properties of pressed alumina­zirconia­silica refractories

Comparative research of the plasticizing binder type (technical lignosulfonate sodium aqueous solution, plasticizing additive on polycarbonate base aqueous solution, as well as technical lignosulfonate sodium and orthophosphoric acid (H3PO4) aqueous solutions mixtures in 3:1 and 1:1 ratio) and its quantity influence on the properties indexes of pressed alumina­zirconia­silica (AZS) refractories were carried out.
 If necessary, the possibility of using any of the studied plasticizing binders for pressing AZS refractories was established. Each of the studied plasticizing binders ensures the receiving of AZS refractories with high indexes of properties. There is a slight tendency to improve the properties of unfired and fired samples of some compositions with binders from plasticizing additives on polycarbonate base aqueous solution and technical lignosulfonate sodium with H3PO4 aqueous solutions mixtures, compared to samples in which the binder is technical lignosulfonate sodium aqueous solution is observed. The best, according to the indicated tendency, is a plasticizing binder from technical lignosulfonate sodium and H3PO4 aqueous solutions mixture in 1:1 ratio. Binders from plasticizing additive on polycarbonate base aqueous solution, technical lignosulfonate sodium and H3PO4 aqueous solution mixture in 3:1 ratio, and technical lignosulfonate sodium aqueous solution are then placed. This tendency should be considered when choosing a plasticizing binder for pressing AZS refractories.
 The raw material base for AZS refractories production has been expanded using the research results.

Molecular‐level Designed Polymer Electrolyte for High‐Voltage Lithium–Metal Solid‐State Batteries

AbstractIn solid polymer electrolytes (SPEs) based Li–metal batteries, the inhomogeneous migration of dual‐ion in the cell results in large concentration polarization and reduces interfacial stability during cycling. A special molecular‐level designed polymer electrolyte (MDPE) is proposed by embedding a special functional group (4‐vinylbenzotrifluoride) in the polycarbonate base. In MDPE, the polymer matrix obtained by copolymerization of vinylidene carbonate and 4‐vinylbenzotrifluoride is coupled with the anion of lithium‐salt by hydrogen bonding and the “σ‐hole” effect of the CF bond. This intermolecular interaction limits the migration of the anion and increases the ionic transfer number of MDPE (tLi+ = 0.76). The mechanisms of the enhanced tLi+ of MDPE are profoundly understood by conducting first‐principles density functional theory calculation. Furthermore, MDPE has an electrochemical stability window (4.9 V) and excellent electrochemical stability with Li–metal due to the CO group and trifluoromethylbenzene (ph‐CF3) of the polymer matrix. Benefited from these merits, LiNi0.8Co0.1Mn0.1O2‐based solid‐state cells with the MDPE as both the electrolyte host and electrode binder exhibit good rate and cycling performance. This study demonstrates that polymer electrolytes designed at the molecular level can provide a broader platform for the high‐performance design needs of lithium batteries.

Portable ppb-level carbon dioxide sensor based on flexible hollow waveguide cell and mid-infrared spectroscopy

We demonstrated a mid-infrared (mid-IR) gas sensor based on a hollow waveguide (HWG) cell, which was fabricated with a flexible polycarbonate (PC) base tube. The HWG inner-coated with silver and silver iodide films achieves a low loss property at 4.26 µm wavelength of carbon dioxide fingerprint absorption. The source and detector of the sensor were broad-spectrum light source and pyroelectric detector with Fabry‐Pérot (FP) filter. The HWG cell is butt-coupled with the light source and detector. No other optical elements are required to ensure the stability of the sensor. The performance of the sensor with HWGs at various lengths and inner diameters was tested and optimized. The sensor with a coiled HWG cell has a limit of detection (LOD) as low as 263 ppb. This scheme provided a simple, miniaturized, and cost-effective solution for trace gas sensing.

Innovative utilization of compact disc for measuring fast neutron generated from a 10 MV medical linear accelerator

Background: High-energy photons produced from a medical linear accelerator (LINAC) have long been used as one of the most effective ways for treating cancers. During the treatment process, some photo neutrons are unavoidably created by [γ,n] reactions, imposing additional and undesirable dose on a patient. This amount of unplanned dose from photo neutrons can potentially harm the patient as well as medical personnel during the treatment. This study is aimed to develop a methodology for measuring fast neutron dose generated from 10 MV LINAC by employing polycarbonate from base material of compact disk (CDs) and a fast neutron converter. Materials and methods: The polycarbonate base layer of CDs has been applied to fast neutron dosimetry with nuclear track method by combining with polymethyl methacrylate (PMMA) converter for fast neutrons. A number of CDs badges were irradiated with high energy photon from 10 MV Elekta Synergy LINAC in the solid water phantom at depth of 0, 2.5, 5, 10, 15 and 20 cm then etched with potassium hydroxide ethanol water (PEW) solution that containing with potassium hydroxide, ethanol and water with ratio of 15:45:40. The optimal condition for the chemical etching were found at 60±2 °C, for 14 hr. Results: Comparison of neutron equivalent doses from measurement of CD track detector and CR-39 track detector has shown that the maximum fast neutron dose equivalent was at depth of 5 cm of phantom. This agreement has confirmed that the CD track detector can be employed to measure fast neutron doses produced from LINAC in an accurate and affordable fashion. Conclusion: It is confirmed that the CD track detector can be employed to measure fast neutron doses produced from LINAC in an accurate and affordable fashion.

Dependence of the structural and rheological properties of a refractory vibrocasting low-cement alumina-chromia castable and the properties of samples from it on the type of dispersant additives

The effect of a new dispersant additive (on a polycarbonate basis) in comparison with a known additive based on polyethylene glycol on the structural and rheological properties of low-cement alumina-chromia castables with a moisture content of 4.5 % (flowability during vibration of freshly prepared castables and the kinetics of changes in the strength of their structure depending on holding time) and on the main properties of castables has been studied.
 Studies of the freshly prepared castables flowability during vibration have established that the additive based on polyethylene glycol has a 1.3 times greater thinning ability compared to the additive on a polycarbonate basis, but the latter is also suitable for the manufacture of vibrocasting aluminachromia castable. It has been shown that the shelf life of the mass with the addition based on polyethylene glycol is 5.5—6.0 hours, and the mass with the addition on the polycarbonate base is 3.0—3.5 hours. During the indicated time, these masses are still mobile and suitable for vibration casting.
 The formation mechanism of a coagulation-condensation-crystallization structure in the mass with the dispersant additive based on polyethylene glycol has been established. The final mechanism of structure formation in the mass with the dispersant additive on a polycarbonate basis is to be studied.
 It was shown that with the introduction of additives studied in this work into the low-cement alumina-chromia castable, castable samples with the additive based on polyethylene glycol were characterized by significantly higher property indices than castable samples with the additive on a polycarbonate base, however, the latter samples also have property indices that meet the specified requirements of the technical specifications. The properties of prepared dried unfired samples with the additive based on polyethylene glycol and on a polycarbonate base, respectively: apparent density — 3.12 and 2.93 g/cm3; cold crushing strength after hydration hardening for 7 days — 64 and 56 N/mm2.
 The properties of samples after firing at a temperature of 1580 °C: apparent density — 3.06 and 2.91 g/cm3; open porosity — 19.8 and 21.9 %; cold crushing strength — 196 and 70 N/mm2, respectively, with the additive based on polyethylene glycol and on a polycarbonate basis. But the properties of samples with the additive on a polycarbonate base are quite high, and it can be used, if necessary, as an alternative additive.
 As a result of the carried out research, the raw material base for the production of coarse-grained alumina-chromia castable and castable products from it has been expanded.

Influence of a new dispersant additive amount on the structural and rheological properties of chamotte concrete and samples from it

The use of dispersing additives in the composition of concrete mixtures helps to reduce water demand, increase flow, increase strength after hardening in air. The effect of a new dispersant additive amount on a polycarbonate base in comparison with the currently used phosphate-containing additive on the structural and rheological properties of chamotte concrete from a mixture of the “SSHBD” grade and samples from it has been investigated. The optimal amount of new dispersant additive on the polycarbonate base has been established and it has been shown that, in its effect on the structural and rheological properties of concrete from a mixture of the “SSHBD” grade and the properties of samples from it, it is similar to the phosphate-containing additive used at present. The change nature of the concrete flowability is practically the same. "Vitality" (i.e. the time period during which the concrete mass is suitable for performing high-quality lining by vibrocasting) of the compared concretes is ~ 4 hours; cold crushing strength of concrete samples with additives after hardening in air for 7 days and heat treatment at a temperature of 110 °C, as well as cold crushing strength of samples after firing at a temperature of 1350 °C are practically the same. The use of new polycarbonate-based dispersant can be recommended for the preparation of chamotte concrete as an alternative phosphate-containing additive.

Characterization of Gas Absorption Modules Based on Flexible Mid-Infrared Hollow Waveguides.

A new gas absorption module, the substrate-embedded hollow waveguide (eHWG) model, is proposed. It consists of a substrate with a curved channel and a hollow waveguide. The hollow waveguide is curved into the channel and works as a gas absorption cell as well as a transmission medium for mid-infrared light. Owing to the low loss property of the hollow waveguide, the signal-to-noise ratio (SNR) was improved for the sensing system. A polycarbonate (PC) base tube was used to obtain flexibility in the fabrication of the hollow waveguide. A silver (Ag) layer and a silver iodide (AgI) layer were inner-coated to ensure a low loss property at the fingerprint wavelength of methane gas. A sensing system was established using a Fourier transform infrared spectrometer (FTIR), an external detector, and an eHWG. Experimental investigations were carried on the sensing performance of eHWGs with various channel shapes. Comparison studies were made on eHWGs embedded with Ag-coated or Ag- and AgI-coated hollow waveguides. The Ag- and AgI-coated hollow waveguides with inner diameters of 0.7, 1.4, and 2.0 mm were used in the eHWGs. The large bore waveguide had low loss but high bending additional loss. The large bore waveguide had a low detection limit due to high coupling efficiency with the light source. A limit of detection (LOD) as low as 2.7 ppm was attained for the system using the eHWG with the long and large bore waveguide.

Multi‐layer archimedean spiral antenna fabricated using polymer extrusion 3D printing

This work describes the design, fabrication, and testing of an Archimedean spiral or spiral antenna using polymer extrusion 3D printing of polycarbonate base material. The spiral antenna design was simulated using CST Microwave Studio®, and the resulting 3D printed antenna characterized in terms of return loss, directivity, and polarization. The antenna design was embedded into a 3D printed structure using a unique ultrasonic method while a ground plane was inserted through a thermal embedding process. These fabrication methods provide process flexibility, which allows multiple conductive antenna layers to be additively constructed in a single build sequence. The method described can be used to create unique electromagnetic structures such as waveguides directly in a 3D printed dielectric part. The spiral antenna was tested with three variations of microstrip feed line used to match 50Ω impedance and introduce a 180° phase shift between the two arms of the spiral. These include a Duroid balun attached to feed of the antenna after fabrication, a Duroid balun embedded into the polycarbonate during fabrication, and the same microstrip design fabricated out of copper mesh and embedded into the structure using the polycarbonate as a dielectric substrate. The results of these three approaches will be discussed. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1662–1666, 2016

An Impact Velocity Device Design for Blood Spatter Pattern Generation with Considerations for High-Speed Video Analysis.

A mechanical device that uses gravitational and spring compression forces to create spatter patterns of known impact velocities is presented and discussed. The custom-made device uses either two or four springs (k1 = 267.8 N/m, k2 = 535.5 N/m) in parallel to create seventeen reproducible impact velocities between 2.1 and 4.0 m/s. The impactor is held at several known spring extensions using an electromagnet. Trigger inputs to the high-speed video camera allow the user to control the magnet's release while capturing video footage simultaneously. A polycarbonate base is used to allow for simultaneous monitoring of the side and bottom views of the impact event. Twenty-four patterns were created across the impact velocity range and analyzed using HemoSpat. Area of origin estimations fell within an acceptable range (ΔXav = -5.5 ± 1.9 cm, ΔYav = -2.6 ± 2.8 cm, ΔZav = +5.5 ± 3.8 cm), supporting distribution analysis for the use in research or bloodstain pattern training. This work provides a framework for those interested in developing a robust impact device.

On-site chip-based colorimetric quantitation of organophosphorus pesticides using an office scanner

Herein we report a scanner-readable plastic microchip for the colorimetric quantitation of organophosphorus (OP) pesticides in food products. The detection principle relies on the irreversible activity inhibition of acetylcholinesterase (AChE) by OP pesticides; AChE catalytically hydrolyzes acetylthiocholine (ATCh) to thiocholine, which in-turn reacts with dithiobis-nitrobenzoic acid (DTNB) to produce a yellow colored product (deprotonated 5-thio-2-nitrobenzoic acid, TNB). The yellow color diminishes upon increasing the concentration of the OP pesticides. In particular, we have fabricated a simple plastic microchip consisting of a transparent polydimethylsiloxane (PDMS) plate with embedded micro-channels (for the colorimetric reaction) attached to a polycarbonate (PC) base plate. A standard flatbed office scanner was used to image the colorimetric reaction at real time, and a commercial photo editing software to read the yellow intensity of the captured images. The detection limit for malathion (one of the most popularly used OP pesticides nowadays) was determined to be 100 ppb, which is below the food safety limits and comparable with conventional spectroscopic detection. The simplicity of the device fabrication and operation of this colorimetric protocol augments its potential for on-site food safety analysis in place of rather expensive and complex spectrometer-based methods.

Development of new reference materials for the determination of cadmium, chromium, mercury and lead in polycarbonate

Reference materials for quantitative determination of Cd, Cr, Hg and Pb in polycarbonate were developed. Reference materials with two concentration level of elements were prepared by adding appropriate amounts of chemicals to a blank polycarbonate base material. It was shown that ten bottles with triplicate analysis are enough to demonstrate the homogeneity of these candidate reference materials. The statistical results also showed no significant trends in both short-term stability test for four weeks and long-term stability test for twelve months. The certification of the four elements was carried out by isotope-dilution-inductively coupled plasma mass spectrometry (ID-ICP-MS) with microwave-assisted digestion. Certification of candidate reference materials in a single laboratory was confirmed with interlaboratory comparison participated by a certain number of well-recognized testing laboratories in Korea. The certified values and expanded uncertainties (k=2) for the candidate reference material with low level and the one with high level were (51.7±2.1)mgkg−1 Cd, (103.8±2.9)mgkg−1 Cd, (98.8±4.5)mgkg−1 Cr, (1004±49.8)mgkg−1 Cr, (107.4±4.6)mgkg−1 Hg, (1133±50.7)mgkg−1 Hg, (94.8±3.7)mgkg−1 Pb and (988.4±53.6)mgkg−1 Pb, respectively. The reference materials developed in this study demonstrated their suitability for the quality assurance in Cd, Cr, Hg and Pb analysis for the implementation of RoHS Directive.

Reading Disc-Based Bioassays with Standard Computer Drives

Traditional methods of disease diagnosis are both time-consuming and labor-intensive, and many tests require expensive instrumentation and trained professionals, which restricts their use to biomedical laboratories. Because patients can wait several days (even weeks) for the results, the consequences of delayed treatment could be disastrous. Therefore, affordable and simple point-of-care (POC) biosensor devices could fill a diagnostic niche in the clinic or even at home, as personal glucose meters do for diabetics. These devices would allow patients to check their own health conditions and enable physicians to make prompt treatment decisions, which could improve the chances for rapid recovery and cure. Compact discs (CDs) provide inexpensive substrate materials for the preparation of microarray biochips, and conventional computer drives/disc players can be adapted as precise optical reading devices for signal processing. Researchers can employ the polycarbonate (PC) base of a CD as an alternative substrate to glass slides or silicon wafers for the preparation of microanalytical devices. Using the characteristic optical phenomena occurring on the metal layer of a CD, researchers can develop biosensors based on advanced spectroscopic readout (interferometry or surface plasmon resonance). If researchers integrate microfluidic functions with CD mechanics, they can control fluid transfer through the spinning motion of the disc, leading to "lab-on-a-CD" devices. Over the last decade, our laboratory has focused on the construction of POC biosensor devices from off-the-shelf CDs or DVDs and standard computer drives. Besides the initial studies of the suitability of CDs for surface and materials chemistry research (fabrication of self-assembled monolayers and oxide nanostructures), we have demonstrated that an ordinary optical drive, without modification of either the hardware or the software driver, can function as the signal transducing element for reading disc-based bioassays quantitatively. In this Account, we first provide a brief introduction to CD-related materials chemistry and microfluidics research. Then we describe the mild chemistry developed in our laboratory for the preparation of computer-readable biomolecular screening assays: photochemical activation of the polycarbonate (PC) disc surface and immobilization and delivery of probe and target biomolecules. We thoroughly discuss the analysis of the molecular recognition events: researchers can "read" these devices quantitatively with an unmodified optical drive of any personal computer. Finally, and critically, we illustrate our digitized molecular diagnosis approach with three trial systems: DNA hybridization, antibody-antigen binding, and ultrasensitive lead detection with a DNAzyme assay. These examples demonstrate the broad potential of this new analytical/diagnostic tool for medical screening, on-site food/water safety testing, and remote environmental monitoring.

Plastic substrate with gas barrier layer and transparent conductive oxide thin film for flexible displays

A novel plastic substrate for flexible displays was developed. The substrate consisted of a polycarbonate (PC) base film coated with a gas barrier layer and a transparent conductive thin film. PC with ultra-low intrinsic birefringence and high temperature dimensional stability was developed for the base film. The retardation of the PC base film was less than 1 nm at a wavelength of 550 nm (film thickness, 120 µm). Even at 180 °C, the elastic modulus was 2 GPa, and thermal shrinkage was less than 0.01%. The surface roughness of the PC base film was less than 0.5 nm. A silicon oxide (SiO x ) gas barrier layer was deposited on the PC base film by a roll-to-roll DC magnetron reactive sputtering method. The water vapor transmission rate of the SiO x film was less than 0.05 g/m 2/day at 40 °C and 100% relative humidity (RH), and the permeation of oxygen was less than 0.5 cc/m 2 day atm at 40 °C and 90% RH. As the transparent conductive thin film, amorphous indium zinc oxide was deposited on the SiO x by sputtering. The transmittance was 87% and the resistivity was 3.5 × 10 − 4 ohm cm.

Construction and characterisation of a modular microfluidic system: coupling magnetic capture and electrochemical detection

This work presents the fabrication and characterisation of a versatile lab-on-a-chip system that combines magnetic capture and electrochemical detection. The system comprises a silicon chip featuring a series of microband electrodes, a PDMS gasket that incorporates the microfluidic channels, and a polycarbonate base where permanent magnets are hosted; these parts are designed to fit so that wire bonding and encapsulation are avoided. This system can perform bioassays over the surface of magnetic beads and uses only 50 μL of bead suspension per assay. Following detection, captured beads are released simply by sliding a thin iron plate between the magnets and the chip. Particles are captured upstream from the detector and we demonstrate how to take further advantage of the system fluidics to determine enzyme activities or concentrations, as flow velocity can be adjusted to the rate of the reactions under study. We used magnetic particles containing β-galactosidase and monitored the enzyme activity amperometrically by the oxidation of 4-aminophenol, enzymatically produced from 4-aminophenyl-β-d-galactopyranoside. The system is able to detect the presence of enzyme down to approximately 50 ng mL−1.

Computed Tomography-based Modeling of Structured Polymers

A hybrid numerical-experimental approach is proposed to characterize the macroscopic mechanical behavior of structured polymers. The method is based on capturing the details of the material's microstructure using 3D X-ray Computed Tomography (CT). By employing segmentation and voxel-conversion, the reconstructed volume is automatically converted into a finite element model that is subsequently used for mechanical analyses. The approach is demonstrated on a 2D polycarbonate (PC) honeycomb. An ideal representative volume element (RVE), with a volume equivalent to the volume of the real X-ray CT-based model, is used to determine the dependence of the macroscopic response of the structure on intrinsic material behavior, strain rate, and cell wall thickness. A nonlinear elasto-viscoplastic constitutive model is used to describe the intrinsic behavior of the PC base material and a comparison with a hyperelastic material model reveals that local plastic deformation significantly influences the macroscopic behavior. A cubic relation between the stiffness of the structure and cell wall thickness is found, whereas the strain rate has a minor influence. The ideal RVE shows a different response compared to the real X-ray CT-based model due to local variations of the cell wall thickness in the latter, causing nonhomogeneous deformations. In addition to the geometric imperfections, jagged edges, as a consequence of voxel conversion, contribute to this local variation in cell wall thickness.

Role of indenter material and size in veneer failure of brittle layer structures

The roles of indenter material and size in the failure of brittle veneer layers in all-ceramic crown-like structures are studied. Glass veneer layers 1 mm thick bonded to alumina layers 0.5 mm thick on polycarbonate bases (representative of porcelain/ceramic-core/dentin) are subject to cyclic contact loading with spherical indenters in water (representative of occlusal biting environment). Two indenter materials-glass and tungsten carbide-and three indenter radii-1.6, 5.0, and 12.5 mm-are investigated in the tests. A video camera is used to follow the near-contact initiation and subsequent downward propagation of cone cracks through the veneer layer to the core interface, at which point the specimen is considered to have failed. Both indenter material and indenter radius have some effect on the critical loads to initiate cracks within the local Hertzian contact field, but the influence of modulus is weaker. The critical loads to take the veneer to failure are relatively insensitive to either of these indenter variables, since the bulk of the cone crack propagation takes place in the contact far field. Clinical implications of the results are considered, including the issue of single-cycle overload versus low-load cyclic fatigue and changes in fracture mode with loading conditions.

A precision translation stage for reproducing measured target volume motions

The development of four‐dimensional (4D) imaging, treatment planning, and treatment delivery methods for radiation therapy requires a quality assurance device that can reproduce clinical motions. Here, we present a high‐precision translation stage for testing and validating 4D techniques. These techniques may require spatial resolutions of 1 mm and temporal resolutions of 2 – 30 Hz for computed tomography imaging, electromagnetic tracking, and fluoroscopic imaging. A one‐dimensional programmable translation stage capable of reproducing idealized and measured anatomic motions common to the thorax and providing support for phantoms weighing up to 27 kg was designed and built to meet the foregoing spatial and temporal resolution requirements. The stage consists of a polycarbonate base and table, driven by an ac servo motor with encoder feedback by means of a belt‐coupled precision screw. Complex motions are made possible by a programmable motion controller that can run multiple independent control and monitoring programs concurrently on independent motion axes. Programmable input and output ports allow motion to be synchronized with beam delivery and other imaging and treatment delivery devices to within 2.0 ms. Average deviations from the programmed positions are typically 0.2 mm or less, and the average maximum positional errors are typically 0.5 mm for an indefinite number of parameterized breathing motion cycles during reproduction of measured target volume motions for several minutes.PACS number: 87.66.Xa

Development of a Microfluidic Device for Detection of Pathogens in Oral Samples Using Upconverting Phosphor Technology (UPT)

Confirmatory detection of diseases, such as HIV and HIV-associated pathogens in a rapid point-of-care (POC) diagnostic remains a goal for disease control, prevention, and therapy. If a sample could be analyzed onsite with a verified result, the individual could be counseled immediately and appropriate therapy initiated. Our group is focused on developing a microfluidic "lab-on-a-chip" that will simultaneously identify antigens, antibodies, RNA, and DNA using a single oral sample. The approach has been to design individual modules for each assay that uses similar components (e.g., valves, heaters, metering chambers, mixers) installed on a polycarbonate base with a common reporter system. Assay miniaturization reduces the overall analysis time, increases accuracy by simultaneously identifying multiple targets, and enhances detector sensitivity by upconverting phosphor technology (UPT). Our microfluidic approach employs four interrelated components: (1) sample acquisition-OraSure UPlink collectors that pick-up and release bacteria, soluble analytes, and viruses from an oral sample; (2) microfluidic processing-movement of microliter volumes of analyte, target analyte extraction and amplification; (3) detection of analytes using UPT particles in a lateral flow system; and (4) software for processing the results. Ultimately, the oral-based microscale diagnostic system will detect viruses and bacteria, associated pathogen antigens and nucleic acids, and antibodies to these pathogens.

Design maps for failure of all-ceramic layer structures in concentrated cyclic loading

A study is made of the competition between failure modes in ceramic-based bilayer structures joined to polymer-based substrates, in simulation of dental crown-like structures with a functional but weak “veneer” layer bonded onto a strong “core” layer. Cyclic contact fatigue tests are conducted in water on model flat systems consisting of glass plates joined to glass, sapphire, alumina or zirconia support layers glued onto polycarbonate bases. Critical numbers of cycles to take each crack mode to failure are plotted as a function of peak contact load on failure maps showing regions in which each fracture mode dominates. In low-cycle conditions, radial and outer cone cracks are competitive in specimens with alumina cores, whereas outer cone cracks prevail in specimens with zirconia cores; in high-cycle conditions, inner cone cracks prevail in all cases. The roles of other factors, e.g. substrate modulus, layer thickness, indenter radius and residual stresses from specimen preparation, are briefly considered.

Shielding Effectiveness Data on Commercial Thermoplastic Materials

Ten different commercially available conductive thermoplastic materials have been tested for near- and far-field shielding effectiveness (SE). Far-field SE was tested using a modified standard measurement technique to provide results comparable with the company-provided data. Further, housings of different thermoplastic materials were constructed and equipped with an electromagnetic interference (EMI) source to model a realistic near-field SE situation. The SE data up to 1 GHz is presented. Conductive thermoplastic materials with fillings of stainless steel fibers and nickel-coated carbon fibers were the two materials that offer the best far-field shielding performance. For the near-field shielding, two materials with filling of stainless steel fibers were the best performing ones. A thermoplastic with polycarbonate (PC) base and stainless steel content of 1.5 vol% showed the best combined far- and near-field shielding results