modified surface
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2022 ◽  
Vol 12 (3) ◽  
pp. 489-493
Author(s):  
Yung-Sheng Yen ◽  
Han-Yi Cheng ◽  
Hung-Ta Lin

The aim of the present study was to investigate the effect of nano-etched surface and diamond-like carbon (DLC) surface acupuncture needles on human pain perception, by finite element method (FEM). Skin models were reconstructed by 3D computer programs. The stress is an important role in acupuncture needle applications for clinical treatment. Many studies have investigated finite element researches for acupuncture; however, few have evaluated a model for acupuncture with and without\ modified surface. The results revealed that abnormal focusing stress was found when acupuncture with nano-etched surface. Moreover, the unbalance stress was found on the top of the skin model in the nano-etched group, the highest stress also appeared in the top region. Acupuncture with nano-etched surface would be an effective means for stimulating skin. These results indicate subtle but significant effects of acupuncture stimulation with nano-etched surface needles, compared to acupuncture with untreated needles in healthy participants.


BIOCELL ◽  
2022 ◽  
Vol 46 (3) ◽  
pp. 829-836
Author(s):  
MAR虯 G. FLORES-S罭CHEZ ◽  
ROBERTO OLAYO ◽  
J. MORALES-CORONA ◽  
ATL罭TIDA M. RAYA-RIVERA ◽  
DIEGO R. ESQUILIANO-REND覰

2022 ◽  
Vol 92 (1) ◽  
pp. 84
Author(s):  
В.И. Проскуряков ◽  
И.В. Родионов

The results of an experimental study of laser pulsed modification of the surface of stainless steel 12CR18NI10T in a layer of alloying compound made of graphite paste and nanodispersed titanium dioxide powder (anatase) and without coating are presented. A comparative analysis of the effect of the coating on the elemental and phase compositions, morphological characteristics and microhardness of the modified surface is carried out. It was found that as a result of the treatment, the processes of cementation and oxidation of the surface occur, which made it possible to obtain a mixture of iron carbide and high-strength oxides in the surface layer of steel. In the samples that underwent laser treatment in the coating layer, an increase in the intensity of the diffraction peaks of the graphite phase and the formation of iron oxides Fe3O4 and chromium Cr2O3 with the presence of titanium dioxide TiO2 were revealed, which created a mixed heterophase metal oxide structure with increased mechanical strength. An increase in the microhardness of the modified surface after laser pulsed scanning in the layer of the experimental alloying compound is established.


2021 ◽  
Author(s):  
Mustafa Mohammed Jabbar ◽  

In current study ,92Nb and 92Mo isotopes have been determined for calculating energy levels and electric quadrupole transition probabilities. Two interaction have been applied in this study are surface delta and modified surface delta interactions. The calculations have been achieved by using appropriate effective charges for proton and neutron as well as parameter length of harmonic potential. Computed results have been compared with the experimental values. After this comparison, energy and the transition probability values have a good agreement with the experimental values, also there are values of the total angular momentum and parity are determined and confirmed for some of the experimental energies, undetermined and unconfirmed experimentally. Theoretically, new values of quadrupole electric transition probabilities have been explored which have not been known in the experimental data.


Author(s):  
A. S. Panasyugin ◽  
N. D. Pavlovskiy ◽  
N. P. Masherova ◽  
A. R. Tsyganov ◽  
I. I. Kurilo

The purpose of this work is to study the process of neutralization of vapors of a mixed solvent of the brand 650 by the adsorption‑catalytic method. The essence of the method consists in the concentration of solvent components on the sorbent, thermal desorption followed by periodic flameless catalytic oxidation of accumulated organic substances to carbon dioxide and water. Synthetic zeolite of the NaX brand was used as a sorbent, and a porous material based on foam ceramics of the Al2O3/SiO2 composition with a highly developed modified surface with an active catalytic phase was used as a catalyst. The mixed solvent contains, xylenes, ethylcellosol, n‑butanol. It is shown that the value of the sorption volume of zeolite for each class of the considered compounds is influenced by certain factors: the length and structure of the carbon skeleton, the position of the hydroxyl group (for alcohols and esters), the number of methyl groups in the composition of molecules (for the production of benzene). The conversion rate of the mixed solvent components was 65.4–90.1 %.


2021 ◽  
Author(s):  
Abdulmalek Shamsan ◽  
Alejandro De la Cruz ◽  
Walmy Jimenez

Abstract This study describes the approach used for enhancing the well integrity that was compromised with gas flow through a casing-casing annulus (CCA). Extremely tight injectivity at a CCA demands a solid free solution which not only can be injected but also resist high differential pressures to provide a long-term barrier in CCA. In this paper a successful leak remediation using an epoxy resin system helped the operator save a well and restart its production. Several pressure tests were conducted for identifying an extremely tight casing leak which was causing formation gas travelling to surface through the annulus. This issue required the customer to look for an efficient remedial solution to seal off the gas leakage and regain productivity. Due to the extremely low injectivity, a conventional cement squeeze or any solid laden particle-based squeeze approach was prone to fail. Alternatively, a tailored solid free epoxy resin system was placed in the annulus using an unconventional placement technique resulted in barrier enhancement and helped the operator place the well back into production. For a mature well flowing through 7 × 9 5/8‑in. and 9 5/8 × 13 3/8‑in., a tailored epoxy-based resin system formulation was placed in the well bore with modified surface operations procedures which helped in eliminating current annular pressure to regain well integrity and production. Remedial operations were performed from the surface by squeezing to seal off the gas coming from the annulus. A Tailored design derived from rigorous lab testing and perfect field execution resulted in CCA pressure remediation in a single attempt of the treatment injection, proving that the concept of using a solids-free resin to enhance existing deteriorated barriers is a reliable method. This epoxy resin system helped the operator to regain the well integrity and production in the shortest time without expensive well intervention operations. Epoxy resin based systems have been identified as a novel solution to remediate barrier integrity for well construction and workover operations, hence such case histories with enhanced operations procedures are helpful in increasing awareness of the benefits that can be attained in challenging high-pressure, low-injectivity environments, and can improve well economics.


2021 ◽  
Vol 28 ◽  
Author(s):  
Shokoufeh Hassani ◽  
Armin Salek Maghsoudi ◽  
Milad Rezaei Akmal ◽  
Shahram Shoeibi ◽  
Fatemeh Ghadipasha ◽  
...  

Background: Zearalenone is a well-known estrogenic mycotoxin produced by Fusarium species, a serious threat to the agricultural and food industries worldwide. Zearalenone, with its known metabolites, are biomarkers of exposure to certain fungi, primarily through food. It has considerable toxic effects on biological systems due to its carcinogenicity, mutagenicity, renal toxicity, teratogenicity, and immunotoxicity. Introduction: This study aims to design a simple, quick, precise, and cost-effective method on a biosensor platform to evaluate the low levels of this toxin in foodstuffs and agricultural products. Methods: An aptamer-based electrochemical biosensor was introduced that utilizes screen-printed gold electrodes instead of conventional electrodes. The electrode position process was employed to develop a gold nanoparticle-modified surface to enhance the electroactive surface area. Thiolated aptamers were immobilized on the surface of gold nanoparticles, and subsequently, the blocker and analyte were added to the modified surface. In the presence of a redox probe, electrochemical characterization of differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy were used to investigate the various stages of aptasensor fabrication. Results: The proposed aptasensor for zearalenone concentration had a wide linear dynamic range covering the 0.5 pg/mL to 100 ng/mL with a 0.14 pg/mL detection limit. Moreover, this aptasensor had high specificity so that a non-specific analyte cannot negatively affect the selectivity of the aptasensor. Conclusion: Overall, due to its simple design, high sensitivity, and fast performance, this aptasensor showed a high potential for assessing zearalenone in real samples, providing a clear perspective for designing a portable and cost-effective device.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7513
Author(s):  
Albena Daskalova ◽  
Emil Filipov ◽  
Liliya Angelova ◽  
Radostin Stefanov ◽  
Dragomir Tatchev ◽  
...  

The use of laser processing for the creation of diverse morphological patterns onto the surface of polymer scaffolds represents a method for overcoming bacterial biofilm formation and inducing enhanced cellular dynamics. We have investigated the influence of ultra-short laser parameters on 3D-printed poly-ε-caprolactone (PCL) and poly-ε-caprolactone/hydroxyapatite (PCL/HA) scaffolds with the aim of creating submicron geometrical features to improve the matrix biocompatibility properties. Specifically, the present research was focused on monitoring the effect of the laser fluence (F) and the number of applied pulses (N) on the morphological, chemical and mechanical properties of the scaffolds. SEM analysis revealed that the femtosecond laser treatment of the scaffolds led to the formation of two distinct surface geometrical patterns, microchannels and single microprotrusions, without triggering collateral damage to the surrounding zones. We found that the microchannel structures favor the hydrophilicity properties. As demonstrated by the computer tomography results, surface roughness of the modified zones increases compared to the non-modified surface, without influencing the mechanical stability of the 3D matrices. The X-ray diffraction analysis confirmed that the laser structuring of the matrices did not lead to a change in the semi-crystalline phase of the PCL. The combinations of two types of geometrical designs—wood pile and snowflake—with laser-induced morphologies in the form of channels and columns are considered for optimizing the conditions for establishing an ideal scaffold, namely, precise dimensional form, mechanical stability, improved cytocompatibility and antibacterial behavior.


2021 ◽  
Vol 2086 (1) ◽  
pp. 012036
Author(s):  
N A Shandyba ◽  
N E Chernenko ◽  
J Y Zhityaeva ◽  
O I Osotova ◽  
M M Eremenko ◽  
...  

Abstract We present the results of studies of the effect of wet chemical treatment on the properties of a GaAs surface modified by a gallium focused ion beam. Our studies based on results of AFM, KpAFM and Raman spectroscopy measurements have shown that, during wet chemical treatment, the damaged areas disappear completely in the case of low accelerating voltages and small doses of ions. At the same time, large accelerating voltages lead to the formation of extended damaged regions, the complete removal of which requires a longer treatment or additional processing.


2021 ◽  
Vol 2144 (1) ◽  
pp. 012031
Author(s):  
T L Mukhacheva ◽  
T M Kalinina ◽  
S A Kusmanov

Abstract The article considers the study of the effect of plasma electrolytic processing on the tribotechnical characteristics of medium-carbon steel. Friction tests were carried out in dry friction mode. Electron microscope and profilometer were used to study the friction tracks. For a comprehensive assessment of the quality of the modified surface layer, the Kragelsky-Kombalov complex parameter was calculated. It was found that plasma electrolytic treatment leads to a decrease in the coefficient of friction and weight wear in comparison with hardened and untreated steel. It has been determined that the mechanism of wear of samples after plasma electrolytic treatment is fatigue wear at boundary friction and plastic contact.


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