105 results match your criteria: "National Institute for Research and Development in Microtechnologies-IMT[Affiliation]"

Plasma-enhanced chemical vapor deposition (PECVD) was used to obtain several graphite nanowall (GNW)-type films at different deposition times on silicon and copper to achieve various thicknesses of carbonic films for the development of electrochemical sensors for the detection of anthracene. The PECVD growth time varied from 15 min to 30 min to 45 min, while scanning electron microscopy (SEM) confirmed the changes in the thickness of the GNW films, revealing a continuous increase in the series. X-ray diffraction (XRD) analysis revealed that the crystallinity of the GNW film samples increased with increasing crystallite size and decreasing dislocation density as the deposition time increased.

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Article Synopsis
  • All-oxide ferroelectric tunnel junctions made from SrRuO/BaTiO/SrTiO perovskites are gaining attention for their potential in high density, low power applications due to their tunable transport properties.
  • Research using first principles calculations reveals that the direction of polarization influences the type of contacts (Schottky or Ohmic) based on the thickness of the SrTiO layer in these junctions.
  • The study finds that while the most responsive interfaces occur in the 2-unit cell thick structures, the magnetoelectric coupling is inadequate to enable polarization switching to control tunnel magnetoresistance, despite the strong ferromagnetism of SrRuO.
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The primary aim of this study was to synthesize and characterize polyurethane (PUR) foams derived from the depolymerization products of poly(ethylene terephthalate) (PET) and MXenes (NbAlC). The depolymerized PET products were produced through a zinc acetate-catalyzed glycolysis process using diethylene glycol (DEG) as solvent. These glycolysis products were then reacted with 4,4'-diphenylmethane diisocyanate (MDI), commercial polyols, and MXenes to produce the PUR foams.

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In the transition to zero waste and sustainable development, it becomes essential to use phase change materials and recycled cement in construction projects to improve energy efficiency and encourage sustainable building practices. The primary goal of this study is to determine how the properties of expanded perlite mortars are affected when Portland cement is partially replaced with recycled cement, produced by thermally treating concrete waste at 550 °C. Recycled cement substituted Portland cement in various percentages (10 %, 30 %, and 50 %).

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Phycocyanin-Loaded Alginate-Based Hydrogel Synthesis and Characterization.

Mar Drugs

September 2024

Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology POLITEHNICA Bucharest, 1-7 Gheorghe Polizu St., 1st District, 011061 Bucharest, Romania.

Phycocyanin was extracted from using conventional extraction (CE), direct ultrasonic-assisted extraction (direct UAE), indirect ultrasonic-assisted extraction (indirect UAE), and microwave-assisted extraction (MAE) methods at different temperatures, extraction intervals, stirring rate, and power intensities while maintaining the same algae to solvent ratio (1:15 ). The optimization of the extraction parameters indicated that the direct UAE yielded the highest phycocyanin concentration (29.31 ± 0.

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This study presents for the first time the polymerization of methyl methacrylate (MMA) in the presence of poly(vinyl chloride) (PVC) that takes place by both SARA-ATRP and SET-LRP mechanisms. The two types of polymerizations that occur in the system are PMMA grafting to the PVC backbone and the formation of a new PMMA polymer, both occurring in the presence of a Cuwire. The polymerizations were controlled as confirmed by the molecular weight evolution, polymerization kinetics, and variations in the dispersity value.

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Article Synopsis
  • * Extensive measurements on a single chip help to evaluate the electrical properties of these nanomesh structures, which are crucial for energy harvesting applications.
  • * The triangle nanomesh structure outperforms the others with excellent characteristics, including a 420 Ω differential resistance, responsivity over 10 V/W, and a low noise equivalent power of 847 pW/√Hz at 0 V.
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An understanding of the mechanical behavior of polymeric materials is crucial for making advancements in the applications and efficiency of nanocomposites, and encompasses their service life, load resistance, and overall reliability. The present study focused on the prediction of the mechanical behavior of biopolymeric nanocomposites with nano-clays as the nanoadditives, using a new modeling and simulation method based on Comsol Multiphysics software 6.1.

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The current study highlights the synthesis and characterization of some nanocomposite materials formed by polymer particles and liquid crystals. The liquid crystals used were cholesteryl benzoate (CLB), and the particles were synthesized by emulsion polymerization in the absence of the emulsifier. Through SEM and DLS analysis, the synthesis of particles of the same size was emphasized, and the amount of CLB showed no influence on these parameters.

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Cancer remains one of the leading causes for death worldwide. Palliative chemotherapy is vital for certain cancer patients, highlighting the critical need for treatment monitoring tools to prevent drug accumulation and mitigate the risk of high toxicity. Therefore, our aim was to evaluate the potential of screen-printed electrodes for the development of sensitive and accurate biosensors for the detection/quantification of antineoplastic drugs.

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The rapid advancement of the Internet of Things (IoT) serves as a significant driving force behind the development of innovative sensors and actuators. This technological progression has created a substantial demand for new flexible pressure sensors, essential for a variety of applications ranging from wearable devices to smart home systems. In response to this growing need, our laboratory has developed a novel flexible pressure sensor, designed to offer an improved performance and adaptability.

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The present communication reports on the effect of the sprayed solution volume variation (as a thickness variation element) on the detailed Raman spectroscopy for WO thin films with different thicknesses grown from precursor solutions with two different concentrations. Walls-like structured monoclinic WO thin films were obtained by the spray deposition method for further integration in gas sensors. A detailed analysis of the two series of samples shows that the increase in thickness strongly affects the films' morphology, while their crystalline structure is only slightly affected.

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Adhesive joints are widely used for structural bonding in various industrial sectors. The performance of bonded joints is commonly attributed to the cleanliness of the substrate and the pre-treatment of the surfaces to be bonded. In this study, the Matrix Assisted Pulsed Laser Evaporation (MAPLE) deposition technique was used for surface modification of aluminum (Al) plates by the deposition of poly(propylene glycol) bis(2-aminopropyl ether) (PPG-NH) of different number average molecular weights (Mn) of 400 g mol, 2000 g mol, and 4000 g mol, respectively.

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We present here the fabrication at the wafer level and the electrical performance of two types of graphene diodes: ballistic trapezoidal-shaped graphene diodes and lateral tunneling graphene diodes. In the case of the ballistic trapezoidal-shaped graphene diode, we observe a large DC current of 200 µA at a DC bias voltage of ±2 V and a large voltage responsivity of 2000 /, while in the case of the lateral tunneling graphene diodes, we obtain a DC current of 1.5 mA at a DC bias voltage of ±2 V, with a voltage responsivity of 3000 .

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Marine waste derived carbon materials for use as sulfur hosts for Lithium-Sulfur batteries.

Bioresour Technol

August 2024

Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland. Electronic address:

Lithium-sulfur batteries are a promising alternative to lithium-ion batteries as they can potentially offer significantly increased capacities and energy densities. The ever-increasing global battery market demonstrates that there will be an ongoing demand for cost effective battery electrode materials. Materials derived from waste products can simultaneously address two of the greatest challenges of today, i.

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Article Synopsis
  • The study emphasizes the importance of on-site detection of glyphosate (Gly) in water using electrochemical sensors to enhance environmental and agricultural monitoring.
  • Two sensor approaches were tested: one modified with gold nanoparticles and graphene for improved conductivity, and another using molecularly imprinted polymers for superior sensitivity, with the latter achieving detection limits as low as 5 ng/L.
  • The research shows promising recovery rates in real water samples, indicating the methods' effectiveness, and suggests future studies on Glyphosate's long-term effects on water quality and ecosystem health.
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Bilayer graphene (Bl-Gr) and sulphur-doped graphene (S-Gr) have been integrated with LiTaOsurface acustic wave (SAW) sensors to enhance the performance of NO detection at room temperature. The sensitivity of the Bl-Gr SAW sensors toward NO, measured at room temperature, was 0.29º/ppm, with a limit of detection of 0.

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Binary Mixtures of Meloxicam and L-Tartaric Acid for Oral Bioavailability Modulation of Pharmaceutical Dosage Forms.

J Funct Biomater

April 2024

Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Bd., 030018 Bucharest, Romania.

Binary mixtures of active pharmaceutical ingredients (API) are researched to improve the oral bioavailability of pharmaceutical dosage forms. The purpose of this study was to obtain mixtures of meloxicam and L-tartaric acid because tartaric acid improves intestinal absorption and meloxicam is more soluble in a weakly basic environment. The mixtures in the 0-1 molar fraction range, obtained from solvent-assisted mechanosynthesis, were investigated by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Fourier Transform Raman spectroscopy (FT-Raman), X-ray powder diffraction (XRD) and solubility tests.

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Effect of Deposition Working Power on Physical Properties of RF-Sputtered CdTe Thin Films for Photovoltaic Applications.

Nanomaterials (Basel)

March 2024

R&D Center for Materials and Electronic & Optoelectronic Devices (MDEO), Faculty of Physics, University of Bucharest, Atomiștilor Street 405, 077125 Măgurele, Ilfov, Romania.

The main objective of this study was to determine the variation in the properties of cadmium telluride (CdTe) thin films deposited on a p-type Si substrate by the radio frequency magnetron sputtering technique at four different working powers (70 W, 80 W, 90 W, and 100 W). The substrate temperature, working pressure, and deposition time during the deposition process were kept constant at 220 °C, 0.46 Pa, and 30 min, respectively.

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Sn-Cu-Ni lead-free solder alloy electrodeposited on copper substrate from a deep eutectic solvent (DES)-based electrolyte under direct current (DC) and pulsed current (PC) was subjected to a reflowing process at the industrial company MIBATRON S.R.L.

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This review presents polyurea (PU) synthesis, the structure-properties relationship, and characterization aspects for ballistic protection applications. The synthesis of polyurea entails step-growth polymerization through the reaction of an isocyanate monomer/prepolymer and a polyamine, each component possessing a functionality of at least two. A wide range of excellent properties such as durability and high resistance against atmospheric, chemical, and biological factors has made this polymer an outstanding option for ballistic applications.

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Dual-Responsive Hydrogels for Mercury Ion Detection and Removal from Wastewater.

Gels

February 2024

Military Technical Academy "Ferdinand I", 39-49 G. Cosbuc Blvd., 050141 Bucharest, Romania.

This study describes the development of a fast and cost-effective method for the detection and removal of Hg ions from aqueous media, consisting of hydrogels incorporating chelating agents and a rhodamine derivative (to afford a qualitative evaluation of the heavy metal entrapment inside the 3D polymeric matrix). These hydrogels, designed for the simultaneous detection and entrapment of mercury, were obtained through the photopolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and N-vinyl-2-pyrrolidone (NVP), utilizing N,N'-methylenebisacrylamide (MBA) as crosslinker, in the presence of polyvinyl alcohol (PVA), a rhodamine B derivative, and one of the following chelating agents: phytic acid, 1,3-diamino-2-hydroxypropane-tetraacetic acid, triethylenetetramine-hexaacetic acid, or ethylenediaminetetraacetic acid disodium salt. The rhodamine derivative had a dual purpose in this study: firstly, it was incorporated into the hydrogel to allow the qualitative evaluation of mercury entrapment through its fluorogenic switch-off abilities when sensing Hg ions; secondly, it was used to quantitatively evaluate the level of residual mercury from the decontaminated aqueous solutions, via the UV-Vis technique.

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Thorough Wide-Temperature-Range Analysis of Pt/SiC and Cr/SiC Schottky Contact Non-Uniformity.

Materials (Basel)

January 2024

Department of Informatics, Mathematics and Electronics, Faculty of Exact Sciences and Engineering, University "1 Decembrie 1918" of Alba Iulia, No. 5 Gabriel Bethlen Street, 510009 Alba Iulia, Romania.

This paper evaluates the non-uniformity degree of platinum and chromium Schottky contacts on silicon carbide. The forward characteristics of experimental samples were acquired in a wide, 60-500 K, temperature range. Microstructural and conventional electrical characterizations were performed, revealing the presence of inhomogeneities on the contact surface.

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The aim of this study involved the synthesis and characterization of polyurethane (PUR) foams obtained from poly(ethylene terephthalate) (PET) depolymerization products and two types of filling agents, namely fly ash and glass waste. The depolymerized PET-based products were obtained by zinc acetate-catalyzed glycolysis process in diethylene glycol (DEG) as a co-reactant. The resulting glycolysis products were contacted with methylene diphenyl diisocyanate, castor oil, and reinforcing agents.

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Red grapes are rich in phytochemicals such as phenolics and flavonoids, which are strongly correlated with their antioxidant activity. Thus, grapes as-harvested and grape extracts, especially those obtained from their seeds and pulp, have been reported to have health benefits, and accordingly, grapes and their derivatives are considered potential functional food ingredients. The total phenolic content, total flavonoid content, and the antioxidant activity of skin, pulp, and seeds of four grape varieties grown both in conventional and organic vineyards were examined in this study.

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