Investigation of Structure and Physical-Mechanical Properties of Metal in Different Zones of Welded Trunk Pipelines Made of X80 Strength Grade Steel

The development of trunk pipelines network, taking into accont their operation in difficult climatic conditions, leads to the creation and the development of non-destructive testing methods to control the stress-strain state of the pipe itself, as well as welded joints. This work presents the results of studies of the microstructure, as well as the mechanical and magnetic characteristics of the metal cut from different zones of the welded joint of X80 strength class pipe steel.

Adsorption of cisplatin by the surface of the magnetic sensitive nanocomposite Fe3O4/Al2O3/С

One of the most widely used antitumor chemotherapeutic drugs is “Cisplatin” (active substance - cis-diaminodichloroplatinum), the side effects of which are the cumulative ototoxic, nephrotoxic and neurotoxic effects. The use of drug carrier systems for targeted delivery and adsorbents for extraction, in particular magnetite-carbon nanocomposites, will minimize unwanted toxic effects without reducing the therapeutic effect of cisplatin. For this purpose, a nanocomposite (NCs) of Fe3O4/Al2O3/С with a carbon surface was synthesized, where a layer of alumina protects magnetite during the pyrolysis of carbohydrates. The synthesized samples were characterized by TEM, XRD, mass spectrometry methods, magnetic properties and specific surface area were studied. It has been found that the used heat treatment mode (T = 500 °С, argon medium) is sufficient for complete carbonization of sucrose and preserves the phase of magnetite which does not lead to deterioration of magnetic characteristics. The results of TEM studies and magnetic measurements indicate the formation of the Fe3O4/Al2O3/С nanocomposite of the core-shell type. The adsorption of Cisplatin on the surface of NCs Fe3O4/Al2O3/С was performed and the adsorption process dependent on the contact time, pH of the solution and cisplatin concentration was studied. The experimental results of kinetic studies were analyzed for compliance with the theoretical models of Boyd and Morris-Weber, models of pseudo-first and pseudo-second orders. Langmuir and Freundlich isotherm models were used to model adsorption processes. The limiting factor of adsorption is the external diffusion mass transfer processes, which correlates with the calculated parameters of the pseudo-first-order model (r2 = 0.985). The correlation of theoretical and practically obtained values of adsorption capacity indicates the possibility of using the Freundlich model to describe the adsorption of Cisplatin on the surface of Fe3O4/Al2O3/C.

Camptothecin-Carrying Cuco2s4 Nanoparticles: Sustained Drug Release And Anticancer Activity

Nanocarriers of anticancer drugs are delicately designed with precision addition at every attempt. In this paper, we report CuCo2S4 nanoparticles that show light-absorption in the NIR-II wavelength range and possess magnetic characteristics. The synthesized nanoparticles are characterized employing XRD, SEM, DLS, TGA, and XPS methods. The nanoparticles form a composite with biocompatible polymeric β-cyclodextrin. The nanoparticles possess a band gap energy of 2.25 eV. The magnetic property arises due to the cobalt-incorporation in the nanoparticles. The anticancer drug, camptothecin, is loaded in the nanocarrier with an 89% adsorption efficiency. The in vitro release of the drug occurs in a sustained fashion. Further, the in vitro anticancer potential of the nanocarrier is examined on breast cancer (MDA=MB-231) cell lines and the activities of the free- and the drug-loaded nanocarrier are compared. The cobalt-containing copper sulfide nanoparticle-poly-β-cyclodextrin composite works as a promising nanocarrier of camptothecin.

OPTIMIZATION OF TECHNOLOGY FOR PRODUCING A COMPOSITE BASED ON BARIUM FERRITE AND BARIUM TITANATE

В работе показано, что в результате спекания образцов композита титанат бария (80 объемных %) - феррит бария (20 объемных %) в фарфоровом тигле при температуре 1300 °С возникает эвтектика. В результате сравнения свойств образцов, полученных при различных температурах спекания, установлено, что оптимальные свойства имеют образцы, спеченные при 1250 °С. Проведено сравнение структуры и диэлектрических свойств образцов керамики титаната бария и композита титанат бария (80 объемных %) - феррит бария (20 объемных %), спеченных при температуре 1250°С. Показано, что добавление в состав титаната бария 20% феррита бария повышает значение диэлектрической проницаемости, пироэлектрического коэффициента и пьезоэлектрического модуля d композита в 1,5 - 2 раза по сравнению с керамикой титаната бария, тогда как значение пьезоэлектрического модуля d остается без изменения. Введение в состав керамики титаната бария 20 % феррита бария достаточно для того, чтобы полученный композит имел магнитные характеристики, соответствующий чистому ферриту бария. It is shown in the work that as a result of sintering of composite samples of barium titanate (80 vol. %) - barium ferrite (20 vol. %) in a porcelain crucible at a temperature of 1300 °C, a eutectic appears. As a result of comparing the properties of the samples obtained at different sintering temperatures, it was found that the samples sintered at 1250 °C have optimal properties. The structure and dielectric properties of barium titanate ceramic samples and barium titanate (80 vol. %) - barium ferrite (20 vol. %) composite sintered at a temperature of 1250 °C are compared. It has been shown that the addition of 20% barium ferrite to the composition of barium titanate increases the dielectric constant, pyroelectric coefficient, and piezoelectric modulus d of the composite of 1,5 - 2 times compared to barium titanate ceramics, while the value of the piezoelectric modulus d remains unchanged. The introduction of 20 % barium ferrite into the barium titanate ceramics is sufficient for the resulting composite to have magnetic characteristics corresponding to pure barium ferrite.

Селективный магнитный контроль толщины и степени упрочнения поверхностных слоев на стальных объектах

The dependences of measured locally magnetic characteristics of surface-hardened steel objects on the thickness and physical properties of their surface layers are studied. It is shown theoretically and experimentally that a change in the thickness of the hardened layer on the surface of steel objects affects on the magnitude of the tangential field component on the surface of the object in the interpolar space significantly , as well as the change in the strength properties of the layer affects the magnitude of the magnetic flux in the "transducer-object" circuit. It is proposed to use this difference in magnetic parameters for selective testing of the surface hardening quality. It is shown that the coercive force measured locally by the internal field and the maximum value of the magnetic flux, which can be measured using a single transducer in single measuring cycle, can be used as diagnostic parameters.