Thin Layer Of Material Research Articles

RETINAL PIGMENT EPITHELIAL DETACHMENTS DEVOID OF RETINAL PIGMENT EPITHELIUM.

To describe two patients with chronic central serous chorioretinopathy showing what appeared to be retinal pigment epithelium detachments lacking imaging findings consistent with retinal pigment epithelium (RPE) over the elevation. The patients underwent comprehensive ophthalmic examination, including multicolor fundus photography, fundus autofluorescence, and spectral-domain optical coherence tomography. A 70-year-old man and a 58-year-old man, diagnosed with chronic central serous chorioretinopathy, showed pigment epithelium detachment-like lesions that were hypoautofluorescent, suggesting an absence of RPE. Spectral-domain optical coherence tomography B scans showed serous, dome-shaped elevations composed of a narrow, mildly hyperreflective band (9-10- µ m thick) that demonstrated hypertransmission of light. The material that constituted the elevation was contiguous with the outer portion of the RPE band at the lesion borders. Based on the multimodal imaging findings, we hypothesize that these pigment epithelial detachments have lost the RPE. A thin layer of material that could represent a residual layer of basal laminar deposit produced by the RPE remains overlying the detachments, possibly accounting for their dome shape and structural stability.

Surface modification of Zr–Nb alloy by nanosecond pulse laser processing

The effect of nanosecond pulse laser processing of the Zr–1% Nb alloy surface of specimens in the annealed state and after their two-stage deformation treatment by abc-pressing and rolling has been investigated. The morphology of the modified surface of specimens is described using optical and scanning microscopy. Furthermore, the microrelief formed as a result of vaporization and melting of a thin layer of material subjected to laser processing is evaluated quantitatively. Durometric measurements were conducted to ascertain the hardness of the near-surface layer and the impact of laser-induced shock waves on its hardness. The electron backscattering diffraction (EBSD) analysis data were employed to describe the structure of the specimens in the near-surface layer. The influence of the initial grain size on the quality of the modified surface, as well as on the depth and hardening of the near-surface layers has been established.

Investigation of thin layer zinc coating on aluminium 6061 substrate using friction stir additive manufacturing process for material development

The thin layer material deposition on aluminum substrate is always an interesting domain of work. The current research work demonstrates the feasibility of thin layer Zn material deposition on Al 6061 substrate material using friction stir additive manufacturing process. The work delivers a detailed investigation on the numerical simulation and experimental work on the friction stir additive manufacturing process for effective coating of Zn layer of thickness 500 μm on aluminum alloy AA 6061. The investigation revealed that the Zn–Al interface temperature reaches to the maximum value of 762 K which is well above the melting point of the Zinc for its effective deposition on the Al substrate. The macrograph shows that the friction stir additive manufacturing process can achieve a consistent distribution of the deposited material across the Zn–Al interface. The study also delivers the analysis of the phase transformation behaviour of the Zn at the joint interface. The results from Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Diffraction (XRD) confirm the presence of zinc in the deposited material. Additionally, tensile testing reveals about the enhancement in mechanical properties of the deposited material. The study can be considered as the preliminary investigation where the feasibility of deposition of a thin layer is established using the friction stir additive manufacturing process for the development of the bimetallic materials.

COMPARISON OF 3D-PRINTED PARTS’ QUALITY USING PRINTERS WITH “COREXY” AND “DELTA” KINEMATICS

Additive manufacturing, or 3D printing, describes technologies that manufacture parts by depositing thin layers of molten material on top of each other and creating the final part layer by layer. Each layer is built on the basis of geometry designed in CAD systems. Additive manufacturing technology opens up new design approaches: "design manufacturing" versus the traditional "design for manufacturing" approach. Geometric freedom allows you to design products as they are visualized, without manufacturing restrictions. Recently, 3D printers with Delta-type kinematics have gained popularity, which is an alternative to standard, cartesian 3D printers. These models use a more complex control system due to differences in the generation of print paths, but may have some advantages over a cartesian configuration. In order to expand the knowledge of additive manufacturing, a comparative study was conducted with cartesian and Delta printers to evaluate the printing performance of the test part. This article examines 3D printers with CoreXY and Delta kinematics, compares their characteristics, and identifies key differences in printing processes. As an example, for quality comparison, arbitrary parts printed in batches of three units from the same material with the same settings inside the slicer program were considered. Parts from both 3D printers were scanned using a LIDAR scanner, and the resulting scan models were transferred to a CAD environment for comparison. The results of the comparison were obtained by the shape and quality of the surface, the production time of one part and batch of parts, mass and dimensional characteristics. Looking at the results, it can be seen that the parts printed by the 3D printer with Delta kinematics have a better surface quality without post-processing, while the parts printed by the 3D printer with kinematics CoreXY correspond as closely as possible to the dimensions specified in the CAD model.

Low-temperature fabrication of amorphous carbon films as a universal template for remote epitaxy

Recently, remote epitaxy has been explored for the fabrication of freestanding semiconductor membranes and substrate re-use. For remote epitaxy a thin 2D material layer is either manually transferred to a substrate or grown directly on a substrate at high temperature, thus limiting the process scalability or the choice of substrates. Here, we report on the low-temperature deposition (300 °C) of ultrathin sp2-hybridized 2D amorphous carbon layers with roughness ≤0.3 nm on III-V semiconductor substrates by plasma-enhanced chemical vapor deposition as a universal template for remote epitaxy. We present growth and detailed characterization of 2D amorphous carbon layers on various host substrates and their subsequent remote epitaxial overgrowth by solid-source molecular beam epitaxy. We observe that a low-temperature nucleation step is favorable for nucleation of III-V material growth on amorphous carbon coated substrates. Under optimized preparation conditions, we obtain high-quality, single-crystalline GaAs, cubic-AlN, cubic-GaN and InxGa1−xAs layers on GaAs, 3C-SiC and InP carbon-coated (001)-oriented substrates. Our results demonstrate a universal template fabrication process for remote epitaxy.

A permutation algorithm for stacking sequence optimization of composite laminates

Structures made of fiber-reinforced composite material are used in many industries, such as automotive, naval, aeronautical, and construction civil. Laminated structures are produced by thin layers of composite material, such as carbon fiber-reinforced laminates, which have high strength and stiffness. These composites are stacked in different orientations in order to provide superior mechanical properties compared to other conventional structures. Due to the number of variables, the conventional design methodology based on trial and error is not attractive, and it is advantageous to use optimization techniques. When designing laminated structures, strength, stiffness, and performance constraints must be satisfied. Using optimization techniques, it is possible to find an optimal lamination scheme that meets the established prerequisites. In this type of structure, the arrangement of the layers and the orientation of the fibers can have a significant impact on the final performance of the structure. The permutation problem in optimization refers to determining the most effective sequence of layers and fiber orientations that meets the design requirements. This work proposes the implementation of a heuristic optimization technique based on design variable permutation. In this specific combinatorial optimization problem, the quantity of layers of each type (i.e. orientation) is known a prior, and the optimal arrangement of these layers is to be evaluated. The algorithm is implemented in Octave language and is demonstrated in optimization of laminated plates.

Investigation of Gamma Ray Shielding Characteristics of Binary Composites Containing Polyester Resin and Lead Oxide.

Ionizing radiation plays an essential role across various fields but also poses significant health risks, requiring effective shielding solutions. This study focuses on the photon shielding properties of PbO-reinforced composites, specifically PbO-0, PbO-2, PbO-4, PbO-6, PbO-8, and PbO-10, through experimental measurements of photon energies ranging from 59.5 keV to 1408.0 keV. The measurements were taken using an HPGe detector. Experimental results were compared to theoretical calculations. Among the tested composites, PbO-10, which contains the highest concentration of lead oxide (PbO), provided the most effective radiation shielding. This sample demonstrated superior mass and linear attenuation coefficients, offering excellent protection at low photon energies. Furthermore, PbO-10 exhibited the lowest half-value layer (HVL) and tenth-value layer (TVL) values, indicating its efficiency in reducing radiation intensity with thinner material layers. It was determined that the experimental TVL results for PbO-O, PbO-2, PbO-4, PbO-6, PbO-8, and PbO-10 at 59.5 keV photon energy were 9.95, 5.98, 4.77, 3.67, 3.22, and 2.71 cm, respectively. With these outstanding attenuation capabilities, PbO-10 is deemed highly suitable for use in medical, industrial, and radiation-heavy environments. In summary, this research emphasizes the effectiveness of PbO-reinforced composites in gamma-ray shielding, with PbO-10 emerging as the top performer, demonstrating great potential for applications that require durable and efficient radiation protection.

Kinetics and Stability of Sustainable Indium Alkaline Electrodeposition

Indium is widely utilised for the fabrication of CuIn1-xGaxSe2 (CIGS) based solar cells1,2. Such devices are constituted by thin layers of various materials stacked on top of each other, one of which is the CuIn1-xGaxSe2 absorber layer itself. Cu-In-Ga alloys as absorber precursors can be obtained using cathodic electrodeposition of each separate elemental layer from three distinct galvanic baths containing Cu2+, In3+, and Ga3+ ions, respectively.State-of-the-art indium galvanic baths display low faradaic efficiency. Being mostly acidic or neutral, these baths are affected by the hydrogen evolution reaction under highly cathodic potentials. The most known alternative to enhance faradaic efficiency is to employ non-aqueous media 3–5.In this study, we present a sustainable alkaline galvanic bath yielding smooth In electrodeposits. Alkaline conditions naturally hinder hydrogen evolution, but favour strong precipitation of In2O3 and In(OH)3. Here, we solved this conundrum by identifying competitive organic compounds capable of complexing In3+, thus avoiding the formation of such precipitates. Moreover, we carried out potentiometric titration experiments to identify the stoichiometry of the coordination compounds.This galvanic bath was formulated, characterized and stabilized for alkaline pH. The faradaic efficiency was assessed and the deposition kinetics explored using coulometric techniques on rotating disk electrodes (RDEs). We are currently investigating the deposition mechanism in detail and plan to leverage the acquired knowledge to further optimize the deposition process. Acknowledgements This work was supported in part by the Italian Ministry of Foreign Affairs and International Cooperation”, grant number US23GR17. REMAP6 has received funding from the European Commission PathFinder open programme under grant agreement No. 101046909. Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Innovation Council and SME Executive Agency (EISMEA). Neither the European Union nor the granting authority can be held responsible for them. References J. Zhou and C. Li, in E3S Web of Conferences,, vol. 267, EDP Sciences (2021).L. Thouin, S. Massaccesi, S. Sanchez, and J. Vedel, Formation of copper indium diselenide by electrodeposition, p. 81–88, (1994).W. Monnens, C. Deferm, K. Binnemans, and J. Fransaer, Physical Chemistry Chemical Physics, 22, 24526–24534 (2020).R. Piercy and N. A. Hampson, The electrochemistry of indium, p. 1–15, (1975).S. Zein El Abedin et al., Electrochim Acta, 52, 2746–2754 (2007).https://re-map.eu/

Aplikasi Edible Coating Pati Sagu dengan Penguat Selulosa Bakterial Terhadap Karakteristik Buah Apel Potong

Quality and shelf life degradation are problems in minimally processed horticultural products (fresh-cut). Edible coating is one way to protect the product from the quality degradation process. Edible coating is a thin layer of edible material applied to the product's surface. One of the potential materials for forming edible films is sago starch. Sago starch-based edible coating has the disadvantage of low mechanical strength and a barrier to water vapor. The addition of bacterial cellulose (BC) filler functions as a physical barrier to vapor and gas while improving its mechanical strength. The treatments applied to fresh-cut Malang apples were without edible coating, with sago edible coating and sago edible coating plus BC. The application of sago edible coating with the addition of BC was able to reduce changes in weight loss by up to 66.4%, and hardness by up to 32.50%, as well as maintaining the total dissolved solids, color (brightness), and acidity level (pH) of fresh-cut apples until the 8th day of storage. Adding BC to the edible coating formula provided a better protective effect than edible coating without BC.

Protective potential of high-contrast mineral-bonded layers on reinforced concrete slabs subjected to uniform shock waves

This study compares the blast performance of reinforced concrete (RC) slabs with and without strengthening on the impact-facing side. The strengthening strategy employed the application of two thin layers of materials with a high mutual stiffness offset, i.e., high-contrast layers. The first is a low-strength, low-modulus damping layer made of infra-lightweight concrete, followed by a second layer of high-ductility fiber-reinforced concrete. The plain RC slabs under investigation vary in thickness of either 40mm or 100mm. The layered specimens consist of a 40mm thick RC slab strengthened with a 40mm damping layer and a 20mm cover SHLC3 layer. This configuration enables a comparison of its behavior with the unstrengthened specimen (a plain 40mm thick RC slab) and a specimen with a similar eigenfrequency (the plain 100mm thick RC slab). The employed shock tube subjects the specimens to two rapidly rising areal pressures: a low-pressure wave reaching approximately 0.4MPa and a high-pressure wave peaking at around 1.2MPa. The study assesses the specimens’ response in terms of accelerations, velocities, and deformations. Additionally, it evaluates damage by analyzing crack patterns, Ultrasonic Pulse Velocity (UPV) measurements, and damping analysis. Overall, the layered specimens exhibited performance nearly equivalent to the 100mm thick specimens, displaying similar deformations and velocities despite having lower mass and bending stiffness. The high-pressure shock wave hardly damaged the layered specimens, unlike the 40mm thick slabs.

Two-dimensional Ruddlesden-Popper perovskite solar cells with an efficiency exceeding 19 % by inserting a self-assembled monolayer

Two-dimensional Ruddlesden-Popper (2DRP) phase perovskites have excellent long-term environmental and structure stability. However, the efficiency of 2DRP perovskite solar cells (PSCs) still lags seriously behind 3D counterparts due to the large exciton binding energy between the large-volume organic spacer and the inorganic plate compared to their 3D analogs. Here, a thin layer of self-assembled monolayer material (2-(3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz-Br) is employed between poly (3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) and β-guanidinopropanoic acid (β-GUA)-based perovskite film (β-GUA)2(FA)4Pb5I16 for efficient and stable 2DRP-based PSCs. The 2PACz-Br-based 2DRP perovskite films show superior crystallinity and quality compared with the control perovskite films. The defect density in 2PACz-Br-based perovskite films is reduced, and the non-radiative recombination is further suppressed. The experimental results show that introducing 2PACz-Br can effectively promote the matched energy levels between the perovskite thin film and the charge-carrier transport layer. Benefiting from the conducive collection and transmission of charge carriers, (β-GUA)2(FA)4Pb5I16 (n = 5)-based PSCs can realize an outstanding power conversion efficiency of 19.13 %, much higher than that of devices without 2PACz-Br modification (17.70 %). Moreover, 2PACz-Br-based 2DRP PSCs show better stability than the control devices. Our work paves the way to efficient and stable 2DRP-based PSCs by inserting a multifunctional self-assembled monolayer.

Electrochemical grafting of diazonium salts on silica-terminated versus H-terminated silicon

Diazonium salts are one of the most widely used molecules for functionalising electrode surfaces, due to their high reactivity toward a range of different electrodes but have mostly been studied on carbon and gold. Recent work has demonstrated that diazonium salts can be reduced on silica-terminated silicon (Si/SiOx) despite silica (SiOx) being an electrically insulating material, but this interesting phenomenon was only demonstrated on one specific crystal orientation, Si(111) using specific diazonium salts molecules – a more complete understanding of the electrochemical properties of these silica-terminated silicon electrodes remains unclear. In this work, we develop a thorough understanding of the reduction of diazonium compounds on silica-terminated silicon using silicon with different crystal orientation and using nano-structured silicon surfaces that are chemically etched to simultaneously expose different crystal orientations. A comparison between the reduction process on oxide free silicon (Si–H) and silica-terminated Si is then made to reveal the effect of the crystal orientation (amorphous vs crystalline) and the insulating nature of the distal surface (Si‒H vs SiOx) on the reduction process. Results show that diazonium salts form, well-packed thin films on silica-terminated silicon regardless of the crystal orientation of the silicon. The rate of diazonium reduction was found to be sensitive to the crystal orientation of Si only when the diazonium salts are in direct contact with the crystal plane (i.e. in contact with Si–H) as opposed to when there is a thin layer of native amorphous oxide material in between. The reduction rate is sufficiently slow on silica-terminated silicon that at slow scan rates, the system reaches a steady state current and become diffusion controlled. This is not observed on oxide-free silicon electrodes which are observed to be governed by a kinetically driven mechanism. These findings deepen our understanding of the electrochemical activity of silica-terminated silicon surfaces which are widely used in solar cells, electronics, chemical and biosensors.

Slicing on the Tessellated Model for the 3D Printing Process based on the Variable Thickness Layers

Additive Manufacturing (AM) is a modern technology that enhances manufacturing by building thin layers of material from digitized (3D) designs, entirely constructed using advanced CAD software. This method facilitates the creation of new types of objects with unique material properties. However, while AM is often hailed as the next industrial revolution, significant challenges remain for its successful commercialization. This project focuses on the microstructural aspects and the dimensional accuracy of the product. Additionally, the paper discusses the slicing algorithm and the material extrusion process in detail.

Characterization of a conductive hydrogel@Carbon fibers electrode as a novel intraneural interface

Peripheral neural interfaces facilitate bidirectional communication between the nervous system and external devices, enabling precise control for prosthetic limbs, sensory feedback systems, and therapeutic interventions in the field of Bioelectronic Medicine. Intraneural interfaces hold great promise since they ensure high selectivity in communicating only with the desired nerve fascicles. Despite significant advancements, challenges such as chronic immune response, signal degradation over time, and lack of long-term biocompatibility remain critical considerations in the development of such devices. Here we report on the development and benchtop characterization of a novel design of an intraneural interface based on carbon fiber bundles. Carbon fibers possess low impedance, enabling enhanced signal detection and stimulation efficacy compared to traditional metal electrodes. We provided a 3D-stabilizing structure for the carbon fiber bundles made of PEDOT:PSS hydrogel, to enhance the biocompatibility between the carbon fibers and the nervous tissue. We further coated the overall bundles with a thin layer of elastomeric material to provide electrical insulation. Taken together, our results demonstrated that our electrode possesses adequate structural and electrochemical properties to ensure proper stimulation and recording of peripheral nerve fibers and a biocompatible interface with the nervous tissue.

Effects of silver diammine fluoride with/without potassium iodide on enamel and dentin carious lesions in primary teeth.

To assess the effects of SDF and SDF+KI treatment on enamel and dentin carious lesions in primary teeth using x-ray Microtomography (XMT) and back scattered scanning electron microscopy (BSE-SEM). Artificial enamel caries of 3 caries free primary teeth were created by immersion of the samples in 50 ml demineralization solution for 72 h. Three other teeth with natural dentin caries were selected. Both groups were divided into 3 subgroups: EC-Enamel Control; ES-Enamel with SDF application; ESK-Enamel with SDF followed by KI application; DC-Dentin Control; DS-Dentin with SDF application; DSK-Dentin with SDF followed by KI application. Each tooth was imaged using XMT at 3 time points: (1) Pretreatment; (2) after immersion in remineralization solution for 120 h, with or without SDF or SDF+KI; (3) after subsequent immersion in demineralization solution for 72 h. The change of radiopacities of the lesions in these time points were assessed from the XMT images. After the XMT scans, all teeth were investigated microscopically using BSE-SEM. In EC, no change in linear attenuation coefficient (LAC) was observed after remineralization, but LAC reduction was observed after subsequent demineralization. For ES, thin layer of high LAC material was deposited on the enamel surface after remineralization, and further reduction of LAC was observed after demineralization. In ESK, the surface layer was lost after SDF+KI, and small reduction of LAC was observed after demineralization. In DC, no LAC change was observed after remineralization, but reduction of LAC was detected after demineralization. In DS, high LAC material was formed on the carious dentin surface and randomly inside the lesion. No further LAC change was found after demineralization. In DSK, thick layer of high LAC material was deposited on the carious surface and inside the dentinal tubules. No further LAC reduction was found after subsequent demineralization. SDF and SDF+KI did not protect artificial enamel under acid attack even though Ag products were deposited in the porous enamel. However, SDF and SDF+KI shows protective properties against acid challenges and Ag products are deposited in carious dentin lesion without tubular structure randomly; and within dentinal tubules when these structures are retained.

Simulation and analysis of solar cells based on InN/p-Si: influence on thickness, doping concentration, and temperature dependence

ABSTRACT The current research project intends to enhance solar cells' power and conversion efficiency based on InN/p-Si utilizing the PC1D simulator. A broad direct bandgap of Indium nitride (0.65 eV) makes it suitable for various applications. The InN-based solar cells show an excellent candidate for generating a higher efficiency device, incorporating well-established silicon substrate technology. The open-source PC1D is well-known software for simulating future solar devices without the need to fabricate real devices. The simulated area was adjusted to 10 cm2. The Si substrate and InN layer thicknesses were designed to be 350 μm and 1×10-3 μm, respectively. The n- and p-regions have doping concentrations of 1×1021 cm-3 and 1×1017 cm-3, respectively. This work analyses the influence of geometrical and technological aspects such as both n-p regions thickness, doping concentrations, and temperature dependency to enhance the conversion efficiency of these structures under the AM1.5G solar spectrum with intensity 0.1 W/cm2. It has been demonstrated that the growth of high-quality InN layers and p-type doping persists to be problematic. It appears challenging to find the most suitable material substrate for InN solar. To produce compatible solar cells with simple structures and cost-effective, however, extremely thin layers of n-layer material are required due to the high absorption coefficient of type III-nitrides. The results illustrate that by adjusting the optimized parameter at room temperature to the lowest temperature (200 K), the solar efficiency may increase up from 19.18% to 27.67%.

Novel Approach for the Preparation of a Highly Hydrophobic Coating Material Exhibiting Self-Healing Properties.

A concept to prepare a highly hydrophobic composite with self-healing properties has been designed and verified. The new material is based on a composite of a crystalline hydrophobic fluoro wax, synthesized from montan waxes and perfluoroethylene alcohols, combined with spherical silica nanoparticles equipped with a hydrophobic shell. Highly repellent layers were prepared using this combination of a hydrophobic crystalline wax and silica nanoparticles. The novel aspect of our concept was to prepare a ladder-like structure of the hydrophobic shell allowing the inclusion of a certain share of wax molecules. Wax molecules trapped in the hydrophobic structure during mixing are hindered from crystallizing; therefore, these molecules maintain a higher mobility compared to crystallized molecules. When a thin layer of the composite material is mechanically damaged, the mobile wax molecules can migrate and heal the defects to a certain extent. The general preparation of the composite is described and XRD analysis demonstrated that a certain share of wax molecules in the composite are hindered to crystallize. Furthermore, we show that the resulting material can recovery its repellent properties after surface damage.

Direct synthesis of controllable ultrathin heteroatoms-intercalated 2D layered materials

Two-dimensional (2D) layered materials have been studied in depth during the past two decades due to their unique structure and properties. Transition metal (TM) intercalation of layered materials have been proven as an effective way to introduce new physical properties, such as tunable 2D magnetism, but the direct growth of atomically thin heteroatoms-intercalated layered materials remains untapped. Herein, we directly synthesize various ultrathin heteroatoms-intercalated 2D layered materials (UHI-2DMs) through flux-assisted growth (FAG) approach. Eight UHI-2DMs (V1/3NbS2, Cr1/3NbS2, Mn1/3NbS2, Fe1/3NbS2, Co1/3NbS2, Co1/3NbSe2, Fe1/3TaS2, Fe1/4TaS2) were successfully synthesized. Their thickness can be reduced to the thinnest limit (bilayer 2D material with monolayer intercalated TM), and magnetic ordering can be induced in the synthesized structures. Interestingly, due to the possible anisotropy-stabilized long-range ferromagnetism in Fe1/3TaS2 with weak interlayer coupling, the layer-independent magnetic ordering temperature of Fe1/3TaS2 was revealed by magneto-transport properties. This work establishes a general method for direct synthesis of heteroatom-intercalated ultrathin 2D materials with tunable chemical and physical properties.

Evaluation of lignin and dip coating for elemental analysis by thin film microextraction followed by laser-induced breakdown spectroscopy

Separation and preconcentration procedures are often necessary to eliminate interferents, enhance sensitivity, and improve detection limits. Conventional solid-phase extraction (batch) finds extensive applications in the determination of various analytes, particularly in low concentrations and complex matrices such as environmental, food, and biological samples. However, drawbacks include high reagent consumption, time-consuming sample processing and low analytical throughput. To address these issues and promote Green Analytical Chemistry (GAC), novel methods have emerged, with solid-phase and liquid-phase microextraction being notable examples. Thin Film Microextraction (TFME) represents an innovative approach involving a solid support coated with a thin layer of adsorbent material, attached to a rod and immersed in the sample solution. Extracted analytes can be quantified either after desorption (elution) or directly on the thin film. This article aims to explore TFME's potential when combined with Laser-Induced Breakdown Spectroscopy (LIBS) for Cd, Cr and Ni determination using lignin as adsorbent material deposited on a solid substrate by dip coating. Under optimized conditions, limits of detection obtained were 1.76 μg kg−1 (Cd), 5.72 μg kg−1 (Cr), and 3.27 μg kg−1 (Ni). The accuracy of the proposed method was evaluated through the analysis of a certified reference material (ERM® CA713), drinking and tap water.

Seismic vulnerability distribution of the earthquake prone area in Central Aceh

Abstract Central Aceh is known as an earthquake-prone area due to the presence of the Sumatra Fault and secondary fault crossing the area resulting the M 6.1 earthquake in 2013. The objective of the research is to investigate seismic vulnerability of Central Aceh. Microtremor observations were conducted at 25 locations in Central Aceh analysed using the Horizontal to Vertical Spectral Ratio (HVSR). Seismic amplification is represented by the maximum values of H/V. The dominant frequency f0 representing the sediment thickness was obtained when the H/V curve is maximum. The frequency values ranged from 14.9 to 25.9 Hz, and the seismic vulnerability values varied from 0.02 to 3.1. The top soil consists of thin layers of sedimentary material dominated by tertiary rocks. The rocks are classified as Type IV and Class I based on the dominant frequency values. This result is consistent with the geology, consisting of sedimentary and volcanic rocks. Areas with a seismic vulnerability value > 1.0 is considered to have a high risk of earthquake damage because they are likely to experience earthquake amplification. Areas with seismic vulnerability value > 1.0 are found in West Aceh and the Geureudong volcano area.