Bayesian Optimization of Hubbard U’s for Investigating InGaN Superlattices

In this study, we undertake a Bayesian optimization of the Hubbard U parameters of wurtzite GaN and InN. The optimized Us are then tested within the Hubbard-corrected local density approximation (LDA+U) approach against standard density functional theory, as well as a hybrid functional (HSE06). We present the electronic band structures of wurtzite GaN, InN, and (1:1) InGaN superlattice. In addition, we demonstrate the outstanding performance of the new parametrization, when computing the internal electric-fields in a series of [InN]1–[GaN]n superlattices (n = 2–5) stacked up along the c-axis.

ANALYZING THE EFFECT OF DENSITY VALUE DEVIATION ON PRINT QUALITY

The quality control activities, in particular the measurement of density values, are part of the quality control parameters carried out by each company. Companies sometimes forget about the quality parameters of the name, even though the quality can give the printed products a good guarantee in the eyes of consumers. To achieve the quality level, of course, the business does not stand idle, there are several things that need to be done or provided by the business to support the quality, namely man (human), machine (machine), material (material), and method (method). In the development of technology in an increasingly advanced digital world, companies want to continue to compete with a digital world by making inroads, this of course gives the products produced by the company a good or a good level of quality. In this discussion, there is an identification of problematic aspects arising from the deviation of density values as well as ways to obtain standard density values and factors that affect the quality of prints on book cover prints using a Heidelberg machine.Keywords—Quality Control, Density, Standart, Product, Deviation

Intercalated architecture of MA2Z4 family layered van der Waals materials with emerging topological, magnetic and superconducting properties

The search for new two-dimensional monolayers with diverse electronic properties has attracted growing interest in recent years. Here, we present an approach to construct MA2Z4 monolayers with a septuple-atomic-layer structure, that is, intercalating a MoS2-type monolayer MZ2 into an InSe-type monolayer A2Z2. We illustrate this unique strategy by means of first-principles calculations, which not only reproduce the structures of MoSi2N4 and MnBi2Te4 that were already experimentally synthesized, but also predict 72 compounds that are thermodynamically and dynamically stable. Such an intercalated architecture significantly reconstructs the band structures of the constituents MZ2 and A2Z2, leading to diverse electronic properties for MA2Z4, which can be classified according to the total number of valence electrons. The systems with 32 and 34 valence electrons are mostly semiconductors. Whereas, those with 33 valence electrons can be nonmagnetic metals or ferromagnetic semiconductors. In particular, we find that, among the predicted compounds, (Ca,Sr)Ga2Te4 are topologically nontrivial by both the standard density functional theory and hybrid functional calculations. While VSi2P4 is a ferromagnetic semiconductor and TaSi2N4 is a type-I Ising superconductor. Moreover, WSi2P4 is a direct gap semiconductor with peculiar spin-valley properties, which are robust against interlayer interactions. Our study thus provides an effective way of designing septuple-atomic-layer MA2Z4 with unusual electronic properties to draw immediate experimental interest.

Kajian pemalsuan bekatul dan tepung ikan di Wilayah Jawa Tengah

<p class="MDPI17abstract"><strong>Objective: </strong>The research aimed examine the quality adulteration of bran and fish meal in the Central Java region.</p><p class="MDPI17abstract"><strong>Methods: </strong>The materials used are rice bran and fish meal originating from 17 regions in Central Java which include Rembang, Jepara, Batang, Solo, Boyolali, Pekalongan, Kendal, Temanggung, Magelang, Ungaran, Pati, Purwodadi, Demak, Salatiga, Kudus, Klaten and Semarang. The research method uses descriptive method. Sampling was carried out by purposive random sample to represent the area of the area used as the research site (10 shops in 1 region with different districts and / or villages). Measurement of the parameters of adulteration on bran used Phloroglucinol test, buoyancy test and specific gravity test, while fish meal used urea test.<strong></strong></p><p class="MDPI17abstract"><strong>Results: </strong>The results showed that the bran which was tested for Phloroglucinol and positive buoyancy was faked by adding husks, and was found in the Pati and Demak areas. Density test describes rice bran with non-standard density in Purwodadi, Kendal, Temanggung, Demak and Semarang. Fish meal adulteration occurred in the Boyolali and Pati regions with positive urea content.<strong></strong></p><p><strong>Conclusions: </strong>The conclusion of this research is that good quality of rice bran based on phloroglucinol test, husk floating test and bulk density test were found in Rembang, Jepara, Solo, Boyolali, Magelang, Ungaran, Salatiga and Kudus areas, the quality of fish meal indicated for adulteration based on the urea test was Pekalongan and Purwodadi areas.</p>

Comparative Analysis of DFTU, ACBN0, and Hybrid Functionals on the Spin Density of YTiO3 and SrRuO3+

We present a quantitative analysis of the theoretical spin density map of two ferromagnetic perovskites, YTiO3 and SrRuO3. We calculated the spin density using the standard density functional theory (DFT)+U method, where the Hubbard U correction is applied to the Ti and Ru ions, and with the pseudo-hybrid ACBN0 method, where the Hubbard U parameters are determined self-consistently. The ACBN0 calculations yielded a large value of the Hubbard U of the oxygen 2p orbitals. We also used the screened hybrid HSE06 functional, which is widely used to describe the electronic structure of oxides. We used the Quantum Theory of Atoms in Molecules (QTAIM) theory and integrated the spin density in the atomic basins instead of projecting on atomic orbitals. This way, our results can be compared to experimental reports as well as to other DFT calculations.

Prominent nonequilibrium effects beyond the standard first-principles approach in nanoscale electronic devices

The standard density functional theory (DFT) based first-principles approach has been widely used for modeling nanoscale electronic devices. A recent experiment, however, reported surprising transport properties of thiol-terminated silanes junctions...

Topology optimization accounting for surface layer effects

Metal AM (additive manufacturing) components are generally inhomogeneous and have different microstructure in the bulk compared with (contour) regions near the surface. This, as well as rough as-built surfaces, affects mechanical properties. In this paper, we develop a topology optimization method that considers such inhomogeneities. The method is a direct extension of standard density-based methods using linear filtering for regularization, and a second filtering of the design variables is used to identify a surface layer, the thickness of which is given by the filter radius. Domain extension is used in order to properly identify such layers at the boundary of the design domain. The method is generally applicable but is demonstrated for stiffness optimization. Both two- and three-dimensional problems are treated. A general property of the method is that the topological complexity is reduced, i.e. the optimized designs get fewer and thicker structural members as the width of the surface layer is increased.

Non-equilibrium neutron stars

Neutron stars contain superdense matter in their interiors. Characteristic densities in their cores are several times higher than the standard density of nuclear matter. This matter is so dense that it would be natural to assume that frequent particle collisions produce immediate equilibration. However, because of the slowness of some reactions, the equilibration with respect to them can be greatly delayed. Then one should deal with non-equilibrium stars which contain extra energy to be released. Deviations from equilibrium can affect neutrino emission of neutron stars, warm up their interiors and influence their thermal evolution. The effects of equilibration can be important for pulsating, rotating, accreting neutron stars, as well as for merging binary neutron stars.

Modeling and thermal calculation of a pipeline insulation system

Energy efficiency of heating networks depends on the costs of the manufacture of insulation materials and components, its installation and exploitation of insulating jacket. As insulation materials for insulation of heating networks, products based on rock wool, polyurethane foam extruded polystyrene foam, foam rubber and polyethylene foam. In this contribution introduced basic principles of calculating the thickness of the thermal insulation of a pipeline by the value of the standard density of the heat flow are given using an example of the use of products based on polyethylene foam. Calculation of the heat flux from the surface of the heat-insulating structure is carried out at a given thickness of the heat-insulating layer if there is a need to determine heat loss (or cold loss). The basis for the calculation is a mathematical model of heat transfer, a developed calculation algorithm and a computer program. The method of installation of thermal insulation depends on the diameter of the pipeline and the selected type of product. Insulating cylinders or cylinders in combination with heat-insulating mats are used for pipelines of small diameters. Roll materials are used to isolate large diameters. Products are fixed on pipelines using mechanical fasteners.