Mechanical and Chemical Characterization of Hard Anodized Cooker Grids Made in Al-Si Alloy

2019 ◽  
Vol 813 ◽  
pp. 334-339
Author(s):  
Fabio Scherillo ◽  
Vincenza Marzocchi ◽  
Antonino Squillace ◽  
Eugenio Amendola
Keyword(s):  
Detrimental Effect ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Chemical Characterization ◽  
Commercially Pure ◽  
Alloy Microstructure ◽  
A Current ◽  
Made In

In the present work the performances of hard anodized component in Al-Si alloy, used as cooker grids, are described in details. The components have been anodized in H2SO4 at low temperature (less than 0 °C) with a current of about 2.4/dm2 A for 70 min.The effect of the alloy microstructure on the quality of the anodized layer is evidentiated, particularly the Si rich intermetallics inside the metal have a detrimental effect on the performance of the oxidized layer.The components have been analyzed by means of nano-indentation to evaluate the mechanical behavior of the layer. The chemical performances have been studied using Electrochemical Impedance Spectroscopy in different solutions (0.05 M Na2SO4 and 0.01 M NaOH). The results obtained have been correlated with the microstructure of the alloy, furthermore all test have been done, for comparison, on Commercially Pure Aluminum anodized in the same conditions of the Al-Si components.The results indicate that the mechanical properties of the anodized layer of Al-Si components are lower to respect that of Commercially Pure Aluminum.On the contrary the chemical resistance of Al-Si anodized items result poor compared to Commercially Pure Aluminum, in particular the oxidized layer is subject to degradations due to the presence of Si rich inclusions.

scholarly journals Effects of Processing Parameters on the Corrosion Performance of Plasma Electrolytic Oxidation Grown Oxide on Commercially Pure Aluminum

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 394 ◽  
Author(s):  
Getinet Asrat Mengesha ◽  
Jinn P. Chu ◽  
Bih-Show Lou ◽  
Jyh-Wei Lee
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Surface Engineering ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Corrosion Performance ◽  
Commercially Pure ◽  
Peo Coatings

The plasma electrolyte oxidation (PEO) process has been considered an environmentally friendly surface engineering method for improving the corrosion resistance of light weight metals. In this work, the corrosion resistance of commercially pure Al and PEO treated Al substrates were studied. The PEO layers were grown on commercially pure aluminum substrates using two different alkaline electrolytes with different addition concentrations of Si3N4 nanoparticles (0, 0.5 and 1.5 gL−1) and different duty cycles (25%, 50%, and 80%) at a fixed frequency. The corrosion properties of PEO coatings were investigated by the potentiodynamic polarization and electrochemical impedance spectroscopy test in 3.5 wt.% NaCl solutions. It showed that the weight gains, layer thickness and surface roughness of the PEO grown oxide layer increased with increasing concentrations of Si3N4 nanoparticles. The layer thickness, surface roughness, pore size, and porosity of the PEO oxide layer decreased with decreasing duty cycle. The layer thickness and weight gain of PEO coating followed a linear relationship. The PEO layer grown using the Na2B4O7∙10H2O contained electrolyte showed an excellent corrosion resistance and low surface roughness than other PEO coatings with Si3N4 nanoparticle additives. It is noticed that the corrosion performance of PEO coatings were not improved by the addition of Si3N4 nanoparticle in the electrolytic solutions, possibly due to its detrimental effect to the formation of a dense microstructure.

scholarly journals Narrative medicine in medical diagnosis

2020 ◽  
pp. 1-5
Author(s):  
Raúl Pino Andrade
Keyword(s):  
Interpersonal Relationships ◽  
Teaching And Learning ◽  
Narrative Medicine ◽  
Medical Field ◽  
History Of ◽  
The Relationship ◽  
Historical Periods ◽  
A Current ◽  
Made In

Modernity has brought with it a series of scientific advances that, in the medical field, have improved not only the diagnosis and treatment of diseases, but also the quality of life of patients. This is undeniable. It is enough to carry out an exercise of imagination and place our life in two different historical settings: first the Renaissance, and second the XXI century or contemporary era. Leaving cultural or historical affinities aside, to the question: In which of these historical periods would you like to live? The most prudent answer is very likely: now, in this century. The advances of medicine can be traced historically, we cannot think about it without thinking in Vesalius, or Paré, and many others; however, it is true that the history of medicine accelerated markedly in the 20th century. Although it is true that in just over a hundred years the greatest scientific discoveries have been made in all fields of knowledge, modernity has also meant a change in time itself. Everything unfolds at previously unimaginable speeds: material and knowledge production, teaching and learning, communication and interpersonal relationships. The latter point should be highlighted, and the changes due to the acceleration of the relationship between doctors and their patients should be pointed out on time. It is as if life should climb the assembly line and obey a Fordist logic. It must be recognized that the acceleration of certain aspects is significant, such as the expansion of diagnostic tests, creation of procedures and medications, immediate response to emergencies, among others. But all these advantages seem to carry with them, as a current, all areas of life including what must necessarily be paused.

scholarly journals Ultra-thin films for plasmonics: a technology overview

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Radu Malureanu ◽  
Andrei Lavrinenko
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Support Surface ◽  
New Materials ◽  
Infra Red ◽  
Plasmon Polaritons ◽  
Plasmon Propagation ◽  
Made In

AbstractUltra-thin films with low surface roughness that support surface plasmon-polaritons in the infra-red and visible ranges are needed in order to improve the performance of devices based on the manipulation of plasmon propagation. Increasing amount of efforts is made in order not only to improve the quality of the deposited layers but also to diminish their thickness and to find new materials that could be used in this field. In this review, we consider various thin films used in the field of plasmonics and metamaterials in the visible and IR range. We focus our presentation on technological issues of their deposition and reported characterization of film plasmonic performance.

scholarly journals The Corrosion Performance of Galvanized Steel in Closed Rusty Seawater

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shuan Liu ◽  
Huyuan Sun ◽  
Ning Zhang ◽  
Lijuan Sun
Keyword(s):  
Hydrostatic Pressure ◽  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Chemical Characterization ◽  
Galvanized Steel ◽  
Corrosion Performance ◽  
Rust Layer ◽  
Tafel Polarization ◽  
Effects Of Temperature

The corrosion performance of galvanized steel in closed rusty seawater (CRS) was investigated using weight loss, Tafel polarization curve, and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were carried out for morphological and chemical characterization of the rust layer absorbed on the zinc coating. Effects of temperature and hydrostatic pressure on corrosion resistance of galvanized steel were studied. Results indicated that rust layer could induce pitting corrosion on the zinc coating under the Cl−erosion; high temperature accelerated the corrosion rate of zinc coating and inhibited the absorption of rust layer; the polarization resistance (Rp) of galvanized steel increased with the increase of hydrostatic pressure in CRS.

scholarly journals Hypericum perforatum: Synthesis of Active Principles during Flowering and Fruitification—Novel Aspects of Biological Potential

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Nebojša Kladar ◽  
Jasminka Mrđanović ◽  
Goran Anačkov ◽  
Slavica Šolajić ◽  
Neda Gavarić ◽  
...  
Keyword(s):  
Hypericum Perforatum ◽  
Chemical Characterization ◽  
Maximum Level ◽  
Malignant Cell ◽  
Antioxidant Potential ◽  
Biological Potential ◽  
Full Flowering ◽  
Close Time

St. John’s wort is a widely used medicinal plant. The quality of herbal drug, which is in most of the cases collected from nature, varies. Therefore, the aim of the present study was detailed chemical characterization of Hypericum perforatum subsp. perforatum samples collected in close time intervals during flowering and fruitification with the purpose to state the phenological stage characterized by maximum levels of active principles. The antioxidant potential and potential to inhibit biologically important enzymes, as well as the cytotoxicity and genotoxicity of the sample collected during the full flowering period, were evaluated. Data showed that the optimal period for the achieving of maximum level of active principles is the phenophase between floral budding and flowering stage. Significant antioxidant potential and the ability to inhibit biologically important enzymes (especially α-glucosidase) were recorded. The extract exhibited no genotoxicity in subcytotoxic concentrations, while increased cytotoxicity recorded in cotreatment with bleomycin on malignant cell lines was especially significant.

Electrochemical Impedance Characterization of Porous Aluminum Oxide after Different Stages of Two-Step Anodization

2014 ◽  
Vol 953-954 ◽  
pp. 1282-1285 ◽  
Author(s):  
Jing Zhe Wang ◽  
Chun Hua Xu ◽  
Wei Cao ◽  
Yan He
Keyword(s):  
Aluminum Oxide ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Aluminum Film ◽  
Equivalent Circuits ◽  
Anodized Aluminum ◽  
Porous Aluminum ◽  
Experimental Parameters ◽  
Impedance Characterization

In this paper, porous anodic aluminum oxide (AAO) membrane was prepared with highly pure aluminum film in 0.3M oxalic acid under dc voltage of 40V at about 8°C by two-step anodization. The morphology of the specimens processed in different stages of two-step anodization was observed with a scanning electron microscope (SEM). The electrochemical behavior of the anodized aluminum after different stages of two-step anodization was studied by electrochemical impedance spectroscopy (EIS). Different equivalent circuits were established to fit EIS experiment data, based on morphologies and structures of AAO during processing. The electrical elements in the equivalent circuits were used to explain experimental parameters.

scholarly journals Antimicrobial activity and chemical characterization of the bark decoction of cumaru stem

2020 ◽  
Vol 50 (3) ◽  
Author(s):  
Maria Jaiana Gomes Ferreira ◽  
Patrícia Coelho do Nascimento Nogueira ◽  
Flayanna Gouveia Braga Dias ◽  
Larissa Morais Ribeiro da Silva ◽  
Edilberto Rocha Silveira ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Salmonella Enteritidis ◽  
Chemical Characterization ◽  
Chemical Compounds ◽  
Stem Bark ◽  
Liquid Chromatography Mass Spectrometry ◽  
1H And 13C Nmr ◽  
Gram Positive Bacteria

ABSTRACT: The plant, Amburana cearensis A. C. Smith (Fabaceae), commonly called cumaru, is widespread in the Caatinga cearense, a less known ecosystem in Brazil. A. cearensis is rich in several compounds like protocatechuic acid, tannins, coumarin, flavonoids and phenolic heterosides, such as amburosides A and B, that have been isolated. The aim of this study was to determine the antimicrobial potential and draw the chemical profile of the distinct characteristics of A. cearensis stem bark decoction, for its possible potential as a food conservation agent. The chemical compounds were characterized by one- and two-dimensional 1H and 13C NMR analyses and Liquid Chromatography-Mass Spectrometry (LCMS). The compounds of coumarin, amburosides A and B, and glycosylated (Z)-o-coumaric acid. Using the plaque microdilution technique, the antimicrobial action was tested on Escherichia coli, Salmonella Enteritidis, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. The decoction demonstrated antimicrobial activity on Gram-positive bacteria. This was encouraging because natural antimicrobials are beneficial for food production, as they can inhibit the pathogenic microorganisms and boost the quality of hygiene and cleanliness.

scholarly journals Analisis Sifat Mekanik Hasil Pengelasan SMAW dengan Akar Las Tig dan Las SMAW pada Pipa API 5L

2019 ◽  
Vol 17 (1) ◽  
pp. 37
Author(s):  
Muas M ◽  
Muhammad Arsyad Suyuti ◽  
Rasul Rasul ◽  
Patta Hajji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bending Strength ◽  
Mechanical Tests ◽  
Current Variation ◽  
Root Face ◽  
A Current ◽  
Root Methods ◽  
Made In

The purpose of this research is to know the mechanical properties of the welds due to the current variation of welding joint API 5L using TIG and SMAW welding root methods. Preparation of specimens of pipe API 5L PSL1 grade X56 (Ø 177.8 mm, length 200 mm, width 7 mm), then specimens preparation were made in a single V 600, root gap 2mm, root face 2mm. Filling the welding roots with TIG welding and SMAW using electrodes E7018 with a current variation 70A, 80A, 90A. Mechanical tests consist of tensile, bending and hard test. The results showed that the quality of a good TIG root weld at 70A, the highest tensile strength of the weld joint 52.27 kgf/mm2 (70A), the highest hardnest 164,217 HRB (90A), the bending strength 1.123,061 N/mm2 (70A) using face bend method and 1,172,959 N/mm2 with root bend. In SMAW root welding, the highest tensile strength 54.27 kgf/mm2 (70 A) , the highest hardnest  158.717 HRB (70 A), the highest bending strength 1.115,611 N/mm2 (70 A) using face bend method, and 1.161,748 N/ mm2 with root bend. 

scholarly journals Chromatographic characterization of pyroligneous liquid obtained from carbonization of peach stone

2019 ◽  
Vol 10 (3) ◽  
pp. 207-218
Author(s):  
Lidiane Schmalfuss Valadão ◽  
Caroline Dos Santos Duarte ◽  
Pedro José Sanches Filho
Keyword(s):  
Industrial Process ◽  
Chemical Characterization ◽  
Raw Material ◽  
Added Value ◽  
Process Conditions ◽  
Physico Chemical ◽  
Color Density ◽  
Agroindustrial Residue

The peach stone is considered an agroindustrial residue originating from the industrial process of peach in halves in syrup. It does not have an adequate destination, its final disposal is incorrect and may cause contamination in the environmental compartments. In this way, the burning of this raw material as biomass enables its reuse, besides adding value to the residue. Among the processes used for the application of this residue is the carbonization process, which allows to obtain co-products with higher added value, such as pyroligneous liquid, which represents a fraction of organic compounds condensed from the smoke emitted during carbonization. The quality of the liquid depends on the process conditions and the biomass used. Therefore, the objective of this study was to characterize the sample of pyrolignous liquid obtained from the carbonization of the peach stone, on an industrial scale, qualitative and semi quantitative. Preliminary characterization (pH, conductivity, color, density and contents of tar, organic matter and acidity) and a chemical characterization by gas chromatography coupled to mass spectrometry (GC-MS) were performed. The liquid presented satisfactory results for the physico-chemical evaluations. Regarding the qualitative determination, it was possible to identify 49 compounds. Highlighting the phenols, with 44.90% of the number of compounds, mainly methoxyphenols. These are compounds with significant added value and industrial importance, indicating their use as raw material in the production of polymer resins, among other purposes.

scholarly journals Rapid Profiling of Soybean Aromatic Compounds Using Electronic Nose

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 66 ◽  
Author(s):  
Ramasamy Ravi ◽  
Ali Taheri ◽  
Durga Khandekar ◽  
Reneth Millas
Keyword(s):  
Volatile Compounds ◽  
Electronic Nose ◽  
Chemical Characterization ◽  
Fast Gas Chromatography ◽  
Off Flavors ◽  
Glycine Max L ◽  
Livestock Feeding ◽  
Identification And Characterization

Soybean (Glycine max (L.)) is the world’s most important seed legume, which contributes to 25% of global edible oil, and about two-thirds of the world’s protein concentrate for livestock feeding. One of the factors that limit soybean’s utilization as a major source of protein for humans is its characteristic soy flavor. This off-flavor can be attributed to the presence of various chemicals such as phenols, aldehydes, ketones, furans, alcohols, and amines. In addition, these flavor compounds interact with protein and cause the formation of new off-flavors. Hence, studying the chemical profile of soybean seeds is an important step in understanding how different chemical classes interact and contribute to the overall flavor profile of the crop. In our study, we utilized the HERCALES Fast Gas Chromatography (GC) electronic nose for identification and characterization of different volatile compounds in five high-yielding soybean varieties, and studied their association with off-flavors. With aroma profiling and chemical characterization, we aim to determine the quantity and quality of volatile compounds in these soybean varieties and understand their effect on the flavor profiles. The study could help to understand soybean flavor characteristics, which in turn could increase soybean use and enhance profitability.

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