Control of electrostatic self-assembly seeding of diamond nanoparticles on carbon nanowalls

Seeding of diamond nanoparticles on vertically-aligned multi-layer graphene, the so-called carbon nanowalls (CNWs), is studied by using deionized water, ethylene glycol, ethanol, and formamide as dispersion mediums. Detonation nanodiamond particles show the smallest mean size and size distribution with a high positive zeta potential when dispersed in ethanol. The contact angle of ethanol on CNWs is almost zero degree, confirming highly wetting behaviour. The diamond nanoparticles dispersed in ethanol are distributed the most uniformly with minimal aggregation on CNWs as opposed to those dispersed in other liquids. The resulting diamond nanoparticle-seeded CNWs, followed by short-term growth in microwave plasma chemical vapor deposition, show a marked decrease in field emission turn-on field down to 1.3 V μm−1 together with a large increase in current density, compared to bare CNWs without diamond seeding. The results provide a way to control the density, size, and uniformity (spacing) of diamond nanoparticles on CNWs and should be applied to fabricate hybrid materials and devices using nanodiamond and nanocarbons.

COMPUTATION OF GRAVITY FIELD FUNCTIONALS WITH A LOCALIZED LEVEL ELLIPSOID

The description of the earth’s gravity field is usually expressed in terms of spherical harmonic coefficients, derived from global geopotential models. These coefficients may be used to evaluate such quantities as geoid undulations, gravity anomalies, gravity disturbances, deflection of the vertical, etc. To accomplish this, a global reference normal ellipsoid, such as WGS84 and GRS80, is required to provide the computing reference surface. These global ellipsoids, however, may not always provide the best fit of the local geoid and may provide results that are aliased. In this study, a regional or localized geocentric level ellipsoid is used alongside the EGM2008 to compute gravity field functionals in the state of Johor. Residual gravity field quantities are then computed using GNSS-levelled and raw gravity data, and the results are compared with both the WGS84 and the GRS80 equipotential surfaces. It is demonstrated that regional level ellipsoids may be used to compute gravity field functionals with a better fit, provided the zero-degree spherical harmonic is considered. The resulting residual quantities are smaller when compared with those obtained with global ellipsoids. It is expected that when the remove-compute-restore method is employed with such residuals, the numerical quadrature of the Stoke’s integral may be evaluated on reduced gravity anomalies that are smoother compared to when global equipotential surfaces are used

A Study on the Mechanical Properties of 3D Printed PLA Specimens According to Infilled Pattern and Printing Direction

This paper intended to measure the material's rigidity according to the orientation of the PLA specimen produced by the FDM method. To measure the change of strength and stiffness according to the direction of stacking of FDM PLA, the specimen was manufactured and tested not only in the direction of stacking but also infill using line pattern and concentric pattern. The intensity of each direction was 38.11MPa with a 0 degree tensile in the line pattern, 3.45 times higher than 11.9MPa with a 90 degree tensile, and 2.15 times higher shear strength with 28.05MPa and 13.88MPa. In concentric pattern, 0 degree tensile was 50.62MPa, 6.25 times higher than 8.46MPa, and 2.23 times higher in shear strength at 13.52MPa compared to 29.56MPa. The biggest difference in zero-degree concentric pattern tensile was the 37% difference in the 0 degree concentric pattern factor. This shows that the difference in intensity according to direction is more pronounced in concentric patterns than line patterns, and the behavior under load will be similar until the breaking point regardless of the direction.

Concept Negation in Kant

Kant distinguishes concept negation from copula negation. While the latter results in a negative judgement, i.e. a judgement denying a property of certain objects, the former gives rise to a negative concept, such as ‘immortal’. Since Kant’s remarks on concept negation are scattered and inconclusive, five interpretations are worked out and put to the test: logical negation, pseudo-negation, attribution of a zero degree, possibility-restricted negation and genus-restricted negation. Whereas the first four interpretations fail for a number of reasons, genus-restricted negation turns out to be tenable.

Human Body Specific Absorption Rate Reduction Employing a Compact Magneto-Dielectric AMC Structure for 5G Massive-MIMO Applications

A compact artificial magnetic conductor (AMC) structure for the application of specific absorption rate (SAR) reduction is presented in this paper. A magneto-dielectric (MD) structure as a host of AMC substrate is used to miniaturize the AMC size. The magneto-dielectric has been designed with a low-profile spiral loop in a way to have a high permittivity and permeability for the desired center frequency of 3.5 GHz. Simulation results confirm the zero-degree reflection phase of the proposed AMC unit cell. Moreover, a 70% reduction has been achieved in comparison to the conventional AMC. To validate the simulation results, a prototype of the board is fabricated and measured with a coplanar waveguide (CPW) antenna for the reflection coefficient. The measurement results display an excellent agreement with the simulation ones. A VOXEL model of a human body is utilized to determine the SAR value of the proposed structure. Considering the maximum SAR value for an average of 10 g human tissue, more than 70% SAR reduction is verified for the CPW antenna with the recommended MD-AMC structure compared to a conventional single CPW antenna.

The Effects of In-Process Cooling during Friction Stir Welding of 7475 Aluminium Alloy

Certain age hardenable alloys such as AA7475 cannot be joined with perfection using fusion welding techniques. This requires non-conventional welding technique such as friction stir welding process to join these ‘difficult to weld’ alloys. In this study, three different cooling conditions i.e. cryogenic, sub-zero, and zero-degree Celsius temperature conditions have been analyzed to understand its impact on the welding process. In-process cooling was found to behave effectively and also enhanced the mechanical properties of the welded joints. A stable microstructure was clearly seen in the images observed under the metallurgical microscope. The weld efficiencies were found to be good in each of the samples which are indicative of a strong metallic joint. The effective cooling conditions employed had an overall positive impact on the joint.

DEGREES OF LATENCY OF ECOLOGICAL DISCOURSE AGENT (A CASE STUDY OF BRITISH ONLINE NEWSPAPERS)

This article proposes a study of degrees of latency of the agent, which is a semantic role performed by a participant of the communicative situation described in a sentence; this role correlates with the instigator of the action. The agent can be expressed explicitly, so that everybody understands who the action is performed by, or in a hidden, latent way. Drawing on Goatly’s (2018) research which demonstrates that degrees of agent’s latency can vary, we modify his scale of latency by taking into consideration non-verbal (visual) means. A great societal concern for environmental issues around the globe nowadays, together with the ecolinguistic vector of this research account for its timeliness. The purpose of this research is to identify the degrees of latency of the agent of environmental discourse. Syntactic constructions, lexical units, and visual images that render the agent were chosen as the object-matter of analysis, while the degrees of latency – as its subject-matter. The methods comprise general scientific methods, such as induction and deduction, synthesis and analysis, observation and contrast, as well as linguistic methods proper: critical discourse analysis, semantic analysis, and multimodal analysis. The sample is selected from online versions of most widely read British newspapers, both broadsheets and tabloids, The Guardian and Metro respectively. A modified scale of degrees of agent’s latency is suggested, where six categories of linguistic means are differentiated according to the degree of their latency. Explicit predication is characterized by a zero degree of latency; its measure increases in grammatical constructions, tropes, nominalizations, ellipsis, and indefinite agent respectively. The prospects of this research lie in comparison and quantitative counts of the agent’s latency in different types of British media.