Interaction of Long Time Pulses of an Nd3+:YAG Laser Beam with the Heusler AlloyNi45Co5Mn35.5In14.5

In this paper, the laser processing of the surface of bulk and layered samples (of thickness 75 nm) of Ni45Co5Mn35.5In14.5 alloy (NC5MI) was investigated using microsecond laser pulses. A Q-switched pulsed Nd3+:YAG laser, operating in the 1st harmonic (which had a wavelength of 1064 nm) with a pulse duration of 250 µs, was used. NC5MI is a metal resistant to thermal laser processing because its reflection coefficient is close to unity for long wavelengths. The aim of this paper was to learn the forms of laser processing (heating, microprocessing, ablation) for which the above-specified type of laser is useful. The samples were irradiated with various fluences in the interval of 5–32 J·cm−2. The effect of the laser interaction with the surface was explored by SEM microscopy. The threshold fluences for the bulk sample were determined as: the visible damage threshold (Fthd = 2 ± 0.2 J·cm−2), the melting threshold (Fthm = 10 ± 0.5 J·cm−2), and the deep melting threshold (Fthdm = 32 J·cm−2). Unexpectedly, these values wereincreased for the layer sample due to its silicon substrate. We have concluded that this type of laser radiation is advantageous for the annealing and melting of, or drilling holes in, the alloy, but disadvantageousto the ablation of the alloy.

Formation of dense plasma on the surface of a stainless steel conductor in superstrong magnetic fields

In experiments on the GIT-12 megaampere generator, the characteristics of conductors made of AISI 321 stainless steel were investigated in the microsecond regime of increasing superstrong magnetic fields. In this regime, a skin explosion of the conductor material takes place with the formation of a dense plasma and its expansion into the interelectrode gap of the vacuum transmission line. The values of the characteristic magnetic field B0 = 100 T are determined, above which there is the effect of nonlinear diffusion of the magnetic field into the conductor, and the critical magnetic field BCT ≅ 260 T, the excess of which leads to the formation of dense plasma on the surface of the massive conductor. A method is proposed for increasing the critical magnetic field on the surface of a conductor up to 1.5 times by choosing the optimal thickness of the conducting surface, and criteria for its determination are given. The effect of increasing the critical magnetic field on the surface of a two-layer sample and creating a pressure in the Mbar range until the moment of formation and expansion of explosion products of an inner conductor with high conductivity has been tested.

Study on the Penetration Depth of Light into Wheat Flour by Hyperspectral Imaging

The penetration depth of light into wheat flour is the basis for the effective detection of additives in wheat flour using hyperspectral imaging. To determine the effective penetration depth of light into different gluten flours in hyperspectral image collection, the partial least squares-discriminant analysis (PLS-DA) method was used. Double-layer samples were prepared by placing flour layers with different thicknesses on top of the benzoyl peroxide (BPO) layer. PLS-DA classification model was established by using the diffuse reflectance spectra of each pixel in the double-layer sample image, and the classification accuracy was used to evaluate the results. The results show that the average accuracy of 1 and 1.5 mm models after smoothing pretreatment is above 95%. Therefore, a 1.5 mm sample depth for the detection of mixed samples of flour and additives is recommended. The selected sample depth was used for the detection of mixed samples containing different concentrations of BPO in flour, and the percentage of detected BPO pixels was positively correlated with BPO concentration, which could be used for subsequent quantitative analysis. The results lay a foundation for the effective detection additives in wheat flour by using hyperspectral imaging technology.

SINTESIS LAPISAN TIPIS TiO2:(F+In) PADA SUBSTRAT KACA DENGAN METODE SPIN-COATING SEBAGAI BAHAN SEL SURYA

ABSTRAKTelah dilakukan penelitian sintesis lapisan tipis TiO2 dengan doping campuran Fluorin dan Indium. Tujuan penelitian ini untuk menghasilkan lapisan tipis yang baik digunakan sebagai salah satu komponen pada sel surya yaitu lapisan absorben. Sintesis lapisan tipis menggunakan metode spin-coating dengan bantuan alat centrifuge yang dimodifikasi. Penelitian ini dilaksanakan di Laboratorium Kimia Dasar dan Kimia Organik, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Mataram. Jenis penelitian ini adalah penelitian eksperimen murni dengan data dianalisis secara deskriptif. Proses sintesis lapisan tipis terdiri dari beberapa tahapan yaitu 1). Persiapan substrat, 2). Pembuatan larutan sol-gel, 3). Deposisi lapisan tipis, dan 4). Pemanasan sampel lapisan tipis. Sampel lapisan tipis diberikan tiga perlakuan berbeda yang terdiri dari 1). Konsentrasi larutan, 2). Jumlah lapisan, dan 3). Variasi suhu pemanasan sampel. Berdasarkan penelitian yang sudah dilakukan didapatkan bahwa semakin besar konsentrasi doping yang digunakan maka semakin gelap permukaan sampel lapisan tipis yang dihasilkan. Kata kunci: sintesis lapisan tipis; TiO2:(F+In); metode spin-coating; sel surya. ABSTRACTResearch on the synthesis of TiO2 thin films with doping mixture of Fluorine and Indium has been carried out. The aim of this research is to produce a thin film which is suitable for use as a component of solar cells, namely the absorbent layer. Synthesis of thin films using the spin-coating method with the help of a modified centrifuge. This research was conducted at the Laboratory of Basic Chemistry and Organic Chemistry, Faculty of Mathematics and Natural Sciences, Mataram University. This type of research is pure experimental research with data analyzed descriptively. The thin layer synthesis process consists of several stages, namely 1). Substrate preparation, 2). Preparation of sol-gel solution, 3). Thin layer deposition, and 4). Heating the thin layer sample. The thin layer sample was given three different treatments consisting of 1). The concentration of the solution, 2). Number of layers, and 3). Variation in sample heating temperature. Based on the research that has been done, it was found that the greater the doping concentration used, the darker the surface of the resulting thin layer sample. Keywords: synthesis thin film, TiO2:(F+In), spin-coating method, solar cells

FTIR INVESTIGATION OF PIGMENTS AND BINDER OF PAINTED WALLS IN HERITAGE MONUMENTS

Studies of materials used for works of art and cultural monuments throughout the history contribute to the comprehensive understanding of particular cultures, their technological achievements and customs over time. Investigations of the authenticity of objects and the interventions they may have endured over time keep an important role for their successful restoration and preservation. A three-layer sample of the colored wall decoration from Ottoman Ćejvan Ćehaja mosque from Mostar, Bosnia and Herzegovina was investigated by FTIR spectroscopy. The plaster was identified as gypsum-lime binder. Inorganic pigments were found in two layers, reddish-brown mixture of Fe2O3 and MnO2 and green pigment recognized as viridian, Cr2O3 ∙ 2H2O. The upper layer of "golden color" is found to be a physically compact piece of gold foil or leaf whose fixation method meets both the Ottoman and "west" mode of binding. The mode of adhesion by animal glue could be the result of decoration immanent to Islamic culture, but also to reconstruction from the late 19th century during the Austro-Hungarian rule in Bosnia.

Engineered Layer-Stacked Interfaces Inside Aurivillius-Type Layered Oxides Enables Superior Ferroelectric Property

Layer engineering with different layer numbers inside Aurivillius-type layered structure, similar to interface engineering in heterojunctions or superlattices, can give rise to excellent physical properties due to the correlated layer-stacked interfaces of two different layer phases with different strain states. In this work, using the solid-state reactions from Aurivillius-type Bi3TiNbO9 (2-layer) and Bi4Ti3O12 (3-layer) ferroelectric powder mixtures, single-phase compound of Bi7Ti4NbO21 with an intergrowth structure of 2-layer and 3-layer perovskite slabs sandwiched between the Bi-O layers was synthesized and the effects of this layer-engineered strategy on the structure, Raman-vibration and ferroelectric properties were systematically investigated. The mostly-ordered intergrowth phase was observed clearly by utilizing X-ray diffraction and advanced electron micro-techniques. Uniformly dispersions and collaborative vibrations of Ti and Nb ions in the layer-engineered Bi7Ti4NbO21 were demonstrated. Remarkably, dielectric and ferroelectric properties were also recorded and an enhanced ferroelectric response was found in the layer-engineered mixed-layer sample with high ferroelectric Curie temperature, compared with the homogeneous 2-layer and 3-layer samples. Analyses of the Raman spectra and atomic structures confirmed that the performance improvement of the layer-engineered sample is intrinsic to the correlated layer-stacked interfaces inside the Aurivillius-type layered oxides, arising from strain-induced lattice distortions at the interfaces.

THE INFLUENCE OF POLYPROPYLENE LAMINATED PAPER ON THE BREAKDOWN STRENGTH OF INSULATION FOR HIGH TEMPERATURE SUPERCONDUCTING CABLE

Polypropylene Laminated Paper (PPLP) and Kraft paper has been used as ac power insulation for conventional cable as well as high temperature superconducting (HTS) cable because of its prominent insulating characteristics. However, research on the use of PPLP/Kraft insulation for HTS cables are thinly scattered. In this paper, the effect of PPLP on the breakdown strength of PPLP/Kraft multi-layer sample impregnated with liquid nitrogen (LN2) under ac and impulse applied voltage was studied. In addition, the breakdown strength characteristics of PPLP and Kraft samples were also investigated in order to determine breakdown strength characteristics of PPLP/Kraft insulation directly. It was found from the experimental data that the breakdown strength increases as the component ratio of PPLP in the PPLP/Kraft sample increases and is slightly affected by the inserting position of PPLP but in impulse case, the breakdown strength strongly depends on the number of PPLP and the relative position of PPLP.

On the influence of lateral cells and local perforation of resonance liner samples on the accuracy of determining their acoustic characteristics in experimental studies

When determining the acoustic characteristics of a single-layer sample of a honeycomb liner by experiments in interferometers with normal wave incidence, a significant effect of incomplete lateral cells of the sample on acoustic characteristics was revealed. The experiments were carried out on two interferometers with channel diameters of 30 and 50 mm in the frequency range 500-3500 Hz at sound pressure levels of 120-155 dB. Based on the results of the experiments, an assessment was made of the effect on the acoustic characteristics of the percentage of perforation, which is the same both for one honeycomb cell and for the entire SAS sample. Based on the results of the research, recommendations were made to improve the accuracy of obtaining the acoustic characteristics of samples of honeycomb liner when testing them in interferometers of normal wave incidence.