Analisis Struktur Mikro dan Kekerasan Paduan Aluminium ADC 12 Hasil Proses Pengecoran Semi Solid dengan Proses Perlakuan Panas

This research aims to analyze the effect of providing additional heat treatment and artificial aging with variations in temperature of quenching and variations in aging time of ADC12 semi-solid casting result which include hardness and microstructure values. The Selected quenching temperature variations are 10°C, 30°C and 50°C. While the aging time variations are 0 h, 1 h, 3 h, 5 h, 7 h, 9 h, 11 h and 13 h. The tests carried out are hardness testing as well as microstructure that will be used to calculate the grain size values and structural density. The highest hardness value was at 180°C, 10°C cooling media variation with 5 h aging time is 83.10 HB. While the smallest grain size value was at the temperature of 10°C cooling media with an aging time of 5 h is 42.797 µm. The optimal value lies at a temperature of 10°C with an aging time of 5 h resulting hardness 83.7911 HB, the average of grain size is 13.5995 µm and the grain density value is 0.8892 with desirability reaching 0.920.

A Study on the Adhesion in the Interfacial Transition Zone Between Glass Fibre Reinforced Rebar and the Cement Matrix

This study is aimed at increasing the adhesion of the fibre-reinforced polymer rods to the binder in the cement-based composites in order to eliminate the problem of rod slippage under loading and broaden the application of composite reinforcement in the construction industry. It is assumed that the better adhesion of reinforcement rod to the cement matrix can be provided by increasing the cement stone structural density, and, in particular, by compacting the structure of the hydration products formed on the surface the fibre-reinforced polymer reinforcement rod. Such increase in strength and density can be achieved by adding nanodispersed additives such as metakaolin, the dispersion of carbon black and Peneco Nano Stachema primer into the composition of the cement matrix. Additional adhesion of the cement matrix to the reinforcement is ensured by coating it with the primer, which seals the structure of the cement matrix located in the interfacial transition zone between the reinforcing bar and the cement stone. Experimental study proved that the proposed approach allows the formation of a strong and dense structure in the interfacial transition zone between the cement matrix and the fibre-reinforced polymer reinforcement rod surface. The introduction of metakaolin and a dispersion of technical soot led to an increase in the adhesion strength of fibre-reinforced polymer rod with a cement matrix by 27% and 29%, respectively. The IR spectral analysis and DTA analysis results showed that the mineralogy and morphology of the hydration products was changed due to the addition of the modifying additives, thus improving the adhesion characteristics and corrosion resistance of fibre- reinforced polymer in the cement-based composites.

Analisis Struktur Mikro dan Kekerasan Paduan Aluminium ADC 12 Hasil Proses Pengecoran Semi Solid dengan Proses Perlakuan Panas

This research aims to analyze the effect of providing additional heat treatment and artificial aging with variations in temperature of quenching and variations in aging time of ADC12 semi-solid casting result which include hardness and microstructure values. The Selected quenching temperature variations are 10°C, 30°C and 50°C. While the aging time variations are 0 h, 1 h, 3 h, 5 h, 7 h, 9 h, 11 h and 13 h. The tests carried out are hardness testing as well as microstructure that will be used to calculate the grain size values and structural density. The highest hardness value was at 180°C, 10°C cooling media variation with 5 h aging time is 83.10 HB. While the smallest grain size value was at the temperature of 10°C cooling media with an aging time of 5 h is 42.797 µm. The optimal value lies at a temperature of 10°C with an aging time of 5 h resulting hardness 83.7911 HB, the average of grain size is 13.5995 µm and the grain density value is 0.8892 with desirability reaching 0.920.

Adaptable Invisibility Management Using Kirigami-Inspired Transformable Metamaterials

Many real-world applications, including adaptive radar scanning and smart stealth, require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic (EM) waves in an on-demand manner. Recently, kirigami technique, affording versatile and unconventional structural transformation, has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner. Here, we report for a kirigami-inspired sparse meta-architecture, with structural density of 1.5% in terms of the occupation space, for adaptive invisibility based on independent operations of frequency, bandwidth, and amplitude. Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures, we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers (A, B, and C) of different geometries characterized by the folding angle β. Our strategy circumvents issues of limited abilities, narrow tuning range, extreme condition, and high cost raised by available reconfigurable metamaterials, providing a new avenue toward multifunctional smart devices.

Using of remote sensing and aeromagnetic data for predicting potential areas of hydrothermal mineral deposits in the Central Eastern Desert of Egypt

This article explored mineral resources and their relation to structural settings in the Central Eastern Desert (CED) of Egypt. Integration of remote sensing (RS) with aeromagnetic (AMG) data was conducted to generate a mineral predictive map. Several image transformation and enhancement techniques were performed to Landsat Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) data. Using band ratios and oriented principal component analysis (PCA) on OLI data allowed delineating hydrothermal alteration zones (HAZs) and highlighted structural discontinuity. Moreover, processing of the AMG using Standard Euler deconvolution and residual magnetic anomalies successfully revealed the subsurface structural features. Zones of hydrothermal alteration and surface/subsurface geologic structural density maps were combined through GIS technique. The results showed a mineral predictive map that ranked from very low to very high probability. Field validation allowed verifying the prepared map and revealed several mineralized sites including talc, talc-schist, gold mines and quartz veins associated with hematite. Overall, integration of RS and AMG data is a powerful technique in revealing areas of potential mineralization involved with hydrothermal processes.

Tutorial on Acoustic Fluid Loading of Structures

Any vibrating structure is loaded by the fluid surrounding it. Whether air, water, or something else, the fluid loading adds a spatially distributed resistance (in phase with the vibration) and reactance (out of phase with the vibration) over the structural surfaces. The resistance absorbs energy, and damps structural vibrations. The reactance is either mass-like, effectively adding to the structural density, reducing resonance frequencies and vibration amplitudes; or stiffness-like, increasing resonance frequencies. Usually, mass-like reactance is caused by fluids external to a structure, and stiffness-like reactance is caused by enclosed volumes of fluids. This tutorial uses analytic methods to compare and contrast external and internal fluid loading on a flat rectangular plate and demonstrates the effects of fluid loading on plate vibration and radiated sound. The well-known stiffening effect of the internal Helmholtz resonance is demonstrated for a thin panel and a shallow entrained cavity. The differences between heavy (water) and light (air) external fluid loading are also demonstrated, with significant reductions in resonance frequencies and peak vibration amplitudes for water loading.

Multi-level characteristics of TiOx transparent non-volatile resistive switching device by embedding SiO2 nanoparticles

TiOx-based resistive switching devices have recently attracted attention as a promising candidate for next-generation non-volatile memory devices. A number of studies have attempted to increase the structural density of resistive switching devices. The fabrication of a multi-level switching device is a feasible method for increasing the density of the memory cell. Herein, we attempt to obtain a non-volatile multi-level switching memory device that is highly transparent by embedding SiO2 nanoparticles (NPs) into the TiOx matrix (TiOx@SiO2 NPs). The fully transparent resistive switching device is fabricated with an ITO/TiOx@SiO2 NPs/ITO structure on glass substrate, and it shows transmittance over 95% in the visible range. The TiOx@SiO2 NPs device shows outstanding switching characteristics, such as a high on/off ratio, long retention time, good endurance, and distinguishable multi-level switching. To understand multi-level switching characteristics by adjusting the set voltages, we analyze the switching mechanism in each resistive state. This method represents a promising approach for high-performance non-volatile multi-level memory applications.

Interdisciplinary data-constrained 3-D potential field modelling with IGMAS+

<p>We introduce a modelling concept for the construction of 3-D data-constrained subsurface structural density models at different spatial scales: from large-scale models (thousands of square km) to regional (hundreds of square km) and small-scale (tens of square km) models used in applied geophysics. These models are important for understanding the drivers of geohazards, for efficient and sustainable extraction of resources from sedimentary basins such as groundwater, hydrocarbons or deep geothermal energy, as well as for investigation of capabilities of long-term underground storage of gas and radioactive materials.</p><p>The modelling concept involves interactive fitting of potential fields (gravity and magnetics) and their derivatives within IGMAS+ (Interactive Gravity and Magnetic Application System), a well-known software tool with almost 40 years of development behind it. The core of IGMAS+ is the analytical solution of the volume integral for gravity and magnetic effects of homogeneous bodies, bounded by polyhedrons of triangulated model interfaces. The backbone model is constrained by interdisciplinary data, e.g. geological maps, seismic reflection and refraction profiles, structural signatures obtained from seismic receiver functions, local surveys etc. The software supports spherical geometries to resolve the first-order effects related to the curvature of the Earth, which is especially important for large-scale models.</p><p>Currently being developed and maintained at the Helmholtz Centre Potsdam – GFZ German Research Centre, IGMAS+ has a cross-platform implementation with parallelization of computations and optimized storage. The powerful graphical interface makes the interactive modelling and geometry modification process user-friendly and robust. Historically IGMAS+ is free for research and education purposes and has a long-term plan to remain so.</p><p>IGMAS+ has been used in various tectonic settings and we demonstrate its flexibility and usability on several lithospheric-scale case studies in South America and Europe.</p><p>Both science and industry are close to the goal of treating all available geoscientific data and geophysical methods inside a single subsurface model that aims to integrate most of the interdisciplinary measurement-based constraints and essential structural trends coming from geology. This approach presents challenges for both its implementation within the modelling software and the usability and plausibility of generated results, requiring a modelling concept that integrates the data methods in a feasible way together with recent advances in data science methods. As such, we present the future outlook of our modelling concept in regards to these challenges.</p>

Multilevel characteristics of TiOx transparent non-volatile resistive switching device by embedding SiO2 nanoparticles

TiOx-bsed resistive switching devices have recently attracted attention as a promising candidate for next-generation non-volatile memory devices. A number of studies have attempted to increase the structural density of resistive switching devices. The fabrication of a multi-level switching device is a feasible method for increasing the density of the memory cell. Herein, we attempt to obtain a non-volatile multi-level switching memory device that is highly transparent by embedding SiO2 nanoparticles (NPs) into the TiOx matrix (TiOx@SiO2 NPs). The fully transparent resistive switching device is fabricated with an ITO/TiOx@SiO2 NPs/ITO structure on glass substrate, and it shows transmittance over 95 % in the visible range. The TiOx@SiO2 NPs device shows outstanding switching characteristics, such as a high on/off ratio, long retention time, good endurance, and distinguishable multi-level switching. To understand multi-level switching characteristics by adjusting the set voltages, we analyze the switching mechanism in each resistive state. This method represents a promising approach for high-performance non-volatile multi-level memory applications.

Comparison of the Technical Performance of Leather, Artificial Leather, and Trendy Alternatives

The market for biogenic and synthetic alternatives to leather is increasing aiming to replace animal-based materials with vegan alternatives. In parallel, bio-based raw materials should be used instead of fossil-based synthetic raw materials. In this study, a shoe upper leather and an artificial leather, and nine alternative materials (Desserto®, Kombucha, Pinatex®, Noani®, Appleskin®, Vegea®, SnapPap®, Teak Leaf®, and Muskin®) were investigated. We aimed to compare the structure and technical performance of the materials, which allows an estimation of possible application areas. Structure and composition were characterized by microscopy and FTIR spectroscopy, the surface properties, mechanical performance, water vapor permeability, and water absorption by standardized physical tests. None of the leather alternatives showed the universal performance of leather. Nevertheless, some materials achieved high values in selected properties. It is speculated that the grown multilayer structure of leather with a very tight surface and a gradient of the structural density over the cross-section causes this universal performance. To date, this structure could neither be achieved with synthetic nor with bio-based materials.