scholarly journals Protective properties of mechanochemically fabricated zeolite/phosphate anticorrosion pigments for paint coatings

2021 ◽  
pp. 107-112
Author(s):  
S.А. Korniy ◽  
◽  
I.М. Zin ◽  
M.-O.М. Danyliak ◽  
O.P. Khlopyk ◽  
...  
Keyword(s):  
Calcium Phosphates ◽  
Electrochemical Corrosion ◽  
Environmentally Friendly ◽  
Anodic Process ◽  
Protective Film ◽  
Protective Properties ◽  
Inhibitory Components ◽  
Phosphate Pigments ◽  
Gradual Release

The anticorrosion environmentally friendly pigments based on synthetic zeolite and zinc and calcium phosphates were prepared by mechanochemical method. The surface morphology and chemical composition of the obtained pigments were determined by scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. It was established that the modification of zeolite by phosphates of divalent metals causes a decrease in the particle size and an increase in the specific surface area of the obtained composite pigments. It was shown that the use of zeolite/phosphate pigments increases the corrosion resistance of the aluminium alloy in 0.1% aqueous NaCl solution. The addition of complex zeolite/phosphate pigments to the sodium chloride solution decelerates the anodic process of electrochemical corrosion, which indicates the formation of a protective film on the metal surface. The composite pigment zeolite/Zn(H2PO4)2 exhibited the highest anticorrosive effect. A gradual release of the inhibitory components from these environmentally friendly pigments provides their long-term action to protect metal products.

scholarly journals Engineering Sr-doping for enabling long-term stable FAPb1−xSrxI3 quantum dots with 100% photoluminescence quantum yield

2021 ◽  
Vol 9 (5) ◽  
pp. 1555-1566
Author(s):  
Andrés F. Gualdrón-Reyes ◽  
David F. Macias-Pinilla ◽  
Sofia Masi ◽  
Carlos Echeverría-Arrondo ◽  
Said Agouram ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Toxic Metals ◽  
Environmentally Friendly ◽  
Photoluminescence Quantum Yield ◽  
Improved Performance ◽  
Pb Substitution

The Pb substitution in quantum dots (PQDs) with lesser toxic metals has been widely searched to be environmentally friendly, and be of comparable or improved performance compared to the lead-perovskite.

scholarly journals SYNTHESIS AND PROTECTIVE PROPERTIES OF PECTIN/MONTMORILLONITE COMPOSITES AGAINST ASPIRIN-INDUCED ENTEROCOLITIS

2020 ◽  
Vol 17 (35) ◽  
pp. 897-907
Author(s):  
Assemgul S. AUYEZKHANOVA ◽  
Eldar T. TALGATOV ◽  
Sandugash N. AKHMETOVA ◽  
Unzira N. KAPYSHEVA ◽  
Alima K. ZHARMAGAMBETOVA
Keyword(s):  
Gastrointestinal Tract ◽  
Adverse Effects ◽  
Hybrid Composites ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Swelling Properties ◽  
Protective Properties ◽  
Pectin Content ◽  
Water Ph

Long term use of aspirin for prevention of cardiovascular events is limited by its gastrointestinal adverse effects, and, therefore, patients at high risk should receive gastroprotective agents. However, gastroprotective drugs also have a few adverse effects that require searching for safe and effective alternatives. The composites combining the swelling properties of clays and the biological activity of polysaccharides seem to be promising candidates for gastrointestinal protection. This study aimed to characterize pectin/montmorillonite composites and evaluate their protective effect on the gastrointestinal tract of rats taking aspirin over a long period. A series of composites based on montmorillonite (ММТ) and low esterified pectin (Pec) was synthesized using the adsorption-precipitation method. The polysaccharide to clay weight ratios were 1:19, 1:9, and 1:4. The composites were characterized using Thermogravimetric Analysis (TGA), Infrared Spectroscopy (IR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). Pectin was completely fixed on MMT, and the polysaccharide content in the composites was approximately 5, 10, and 20 wt%, respectively. The shifting of the absorption band of the C=O group of the pectin indicated the interaction of the polysaccharide with the clay, confirming effective immobilization of Pec on MMT. Modification with pectin changed the morphology and structure of the MMT due to the surface coating and intercalation into the interlayer space. The composites swelled in acidified water (pH = 2.0), and their swelling ability was higher to compare with unmodified MMT. The sorption capacity of Pec/MMT composites towards acetylsalicylic acid (ASA) was decreased from 6.8 to 1.0 mg g-1 with increasing of pectin content from 5 to 20 wt%. The hybrid composites promoted the protection of the gastrointestinal tract of rats, which were administered ASA with Pec/MMTs for 16 days. Protective properties of the Pec/MMT have been improved with increasing pectin content from 5 to 20 wt%.

Eco-friendly castor oil-based UV-curable urethane acrylate zinc oxide nanocomposites: Synthesis and viscoelastic behavior

2019 ◽  
Vol 54 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Abbas Madhi ◽  
Behzad S Hadavand
Keyword(s):  
Zinc Oxide ◽  
Castor Oil ◽  
Zinc Oxide Nanoparticles ◽  
Viscoelastic Behavior ◽  
Environmentally Friendly ◽  
Urethane Acrylate ◽  
Nano Zno ◽  
Uv Curable ◽  
Maximum Value

Attention to environmental problems and the importance of maintaining it have caused the researchers to pay more attention in this regard. The production of polymers and resins has increased in recent years and has affected by environmental pollution due to their long-term degradation. An appropriate solution to this problem is the synthesis of degradable and environmentally friendly polymers and resins. Using natural materials in the synthesis of polymers and resins can help them to be environmentally friendly. The purpose of this research is to synthesize urethane acrylate resins using natural resources. For this purpose, the urethane acrylate pre-polymer was synthesized with castor oil. Then, using modified zinc oxide nanoparticles with 1, 3 and 5 wt% urethane acrylate zinc oxide nanocomposites were produced. The use of castor oil as a degradable part and lack of organic solvent in radiation systems led to the creation of an environmentally friendly resin. Subsequently, the viscoelastic behavior of the prepared nanocomposite was evaluated. Spectrometry results confirm the synthesized resin structure. The morphology of nanocomposites confirmed the proper particle size distribution in a 3 wt.% sample. The results of the dynamic mechanical thermal analysis test showed that increasing the amount of modified nano ZnO could increase the glass transition temperature, and the maximum value was observed in 5 wt.% modified nano ZnO (69.7℃).

Electrochemical Corrosion Behaviour of ZrN Film in Various Corrosive Fluid

2015 ◽  
Vol 3 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Vishnu R. ◽  
Jiten Das ◽  
S. B. Arya ◽  
Manish Roy
Keyword(s):  
Sea Water ◽  
Corrosion Behaviour ◽  
Water Solution ◽  
Electrochemical Corrosion ◽  
High Hardness ◽  
Corrosion Current ◽  
Plain Carbon Steel ◽  
Open Circuit ◽  
Protective Film ◽  
Hank’S Solution

Recently, ZrN has been attracting interest for its excellent corrosion resistance, biocompatibility, high hardness, good lubricity and ductility. Although tribological study of ZrN coating has been carried out extensively, investigation related to corrosion of ZrN film is limited. In view of this and in view of possible applications of ZrN film in several engineering components, the present investigation has been undertaken to evaluate the corrosion response of ZrN film in seawater solution, Hank's solution, 0.5M H2SO4solution and 0.5M HCl solutions. Towards that purpose, potentiostatic, open circuit potential and potentiodynamic study of ZrN film deposited on plain carbon steel has been carried out in all these solutions. Results indicate that stable protective film is formed on the surface of ZrN coating in all these solution except 0.5M H2SO4 solution. The formation of protective film on ZrN coating is fastest in sea water solution and it is slowest in the Cl¯ ions containing media, 0.5 M HCl. The corrosion current is highest for 0.5M H2SO4 acid solution and least for Hank's solution.

Long-Term Depression of Temporoammonic-CA1 Hippocampal Synaptic Transmission

1999 ◽  
Vol 81 (3) ◽  
pp. 1036-1044 ◽  
Author(s):  
Hannah Dvorak-Carbone ◽  
Erin M. Schuman
Keyword(s):  
Synaptic Transmission ◽  
Calcium Influx ◽  
Hippocampal Slices ◽  
Low Frequency ◽  
Nmda Receptor Antagonist ◽  
Long Term Depression ◽  
Field Recordings ◽  
Old Rats ◽  
Inhibitory Components

Long-term depression of temporoammonic-CA1 hippocampal synaptic transmission. The temporoammonic pathway, the direct projection from layer III of the entorhinal cortex to area CA1 of the hippocampus, includes both excitatory and inhibitory components that are positioned to be an important source of modulation of the hippocampal output. However, little is known about synaptic plasticity in this pathway. We used field recordings in hippocampal slices prepared from mature (6- to 8-wk old) rats to study long-term depression (LTD) in the temporoammonic pathway. Low-frequency (1 Hz) stimulation (LFS) for 10 min resulted in a depression of the field response that lasted for ≥1 h. This depression was saturable by multiple applications of LFS. LTD induction was unaffected by the blockade of either fast (GABAA) or slow (GABAB) inhibition. Temporoammonic LTD was inhibited by the presence of the N-methyl-d-aspartate (NMDA) receptor antagonist AP5, suggesting a dependence on calcium influx. Full recovery from depression could be induced by high-frequency (100 Hz) stimulation (HFS); in the presence of the GABAA antagonist bicuculline, HFS induced recovery above the original baseline level. Similarly, HFS or θ-burst stimulation (TBS) applied to naive slices caused little potentiation, whereas HFS or TBS applied in the presence of bicuculline resulted in significant potentiation of the temporoammonic response. Our results show that, unlike the Schaffer collateral input to CA1, the temporoammonic input in mature animals is easy to depress but difficult to potentiate.

scholarly journals Impact of a Model Used to Simulate Chronic Socio-Environmental Stressors Encountered during Spaceflight on Murine Intestinal Microbiota

2020 ◽  
Vol 21 (21) ◽  
pp. 7863
Author(s):  
Corentine Alauzet ◽  
Lisiane Cunat ◽  
Maxime Wack ◽  
Laurence Lanfumey ◽  
Christine Legrand-Frossi ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Intestinal Microbiota ◽  
Space Mission ◽  
Psychosocial Stressors ◽  
Mild Stress ◽  
Protective Properties ◽  
Β Diversity ◽  
Intestinal Dysbiosis ◽  
The Impact

During deep-space travels, crewmembers face various physical and psychosocial stressors that could alter gut microbiota composition. Since it is well known that intestinal dysbiosis is involved in the onset or exacerbation of several disorders, the aim of this study was to evaluate changes in intestinal microbiota in a murine model used to mimic chronic psychosocial stressors encountered during a long-term space mission. We demonstrate that 3 weeks of exposure to this model (called CUMS for Chronic Unpredictable Mild Stress) induce significant change in intracaecal β-diversity characterized by an important increase of the Firmicutes/Bacteroidetes ratio. These alterations are associated with a decrease of Porphyromonadaceae, particularly of the genus Barnesiella, a major member of gut microbiota in mice and humans where it is described as having protective properties. These results raise the question of the impact of stress-induced decrease of beneficial taxa, support recent data deduced from in-flight experimentations and other ground-based models, and emphasize the critical need for further studies exploring the impact of spaceflight on intestinal microbiota in order to propose strategies to countermeasure spaceflight-associated dysbiosis and its consequences on health.

scholarly journals A new environmentally-friendly route to in situ form a high-corrosion-resistant nesquehonite film on pure magnesium

RSC Advances ◽  
2020 ◽  
Vol 10 (58) ◽  
pp. 35480-35489 ◽  
Author(s):  
Xianlong Cao ◽  
Quanyou Ren ◽  
Youkun Yang ◽  
Xianglong Hou ◽  
Yongbo Yan ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Environmentally Friendly ◽  
Pure Magnesium ◽  
Protective Film ◽  
High Corrosion Resistance ◽  
Corrosion Resistant ◽  
High Corrosion

A nesquehonite protective film with high corrosion resistance was prepared on pure Mg via a new environmentally-friendly in situ carbonation route.

The Preparation and Evaluation of the Combined Artificial Bone

2011 ◽  
Vol 140 ◽  
pp. 1-6 ◽  
Author(s):  
Ke Ya Mao ◽  
Fei Hu Zhou ◽  
Fu Zai Cui ◽  
Jiang Tao Li ◽  
Zi Shen Cheng ◽  
...  
Keyword(s):  
Bone Graft ◽  
Calcium Phosphates ◽  
Bone Transplantation ◽  
Artificial Bone ◽  
Synthetic Materials ◽  
Extraction Site ◽  
Bone Graft Substitutes ◽  
Long Term Performance ◽  
Term Performance

Every year, roughly two million patients worldwide sustain a bone grafting procedure to repair bone defects stemming from tumor, the wound, the infection, as well as other reasons [1, 2]. The bone transplantation is one of main methods to treat bone damages [3]. The gold standard is to use autologous bone or autograft [4]. However, both the need of the second surgery and morbidity at the extraction site [5-7] has been an incentive to search for alternative treatment. One of them is to form bone graft bone. Many materials have been widely chosen to form bone graft substitutes: metals, polymers, ceramics, dehydrate, and calcium phosphates [8-13]. Although these synthetic materials provide an immediate solution for many patients, their long-term performance is generally not satisfactory. This is often due to a mechanical property mismatch between the implant failure and tissue damage [14, 15]. The development of combined artificial bone with improved mechanical properties and enhanced biocompatibility calls for a biomimetic approach using natural bone as a guide.

scholarly journals The high temperature oxidation of metals

1926 ◽  
Vol 111 (757) ◽  
pp. 203-209 ◽  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperature Oxidation ◽  
Protective Action ◽  
Protective Film ◽  
Parent Metal ◽  
Compact Structure ◽  
Temperature Oxidation ◽  
Protective Properties ◽  
Porous Oxide

The oxidation of metals at high temperatures has been investigated with some thoroughness by Pilling and Bedworth. They found that the metals could be divided into two great classes according to the nature of the oxide produced. If the volume of the oxide is greater than that of the metal from which it was produced an oxide film of compact structure and protective properties will be produced. If the volume of the oxide is less than that of its parent metal a porous oxide is produced which has no protective action whatever. The oxidation of the metals of the first class is controlled by the diffusion of oxygen through the protective film of oxide and the application of the diffusion laws to this process lead us to expect that the oxidation law will be W 2 = K t W 2 = amount of oxygen absorbed t = time K is a constant.

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