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This paper provides deeper insights into the performance of diamond particulate reinforced refractory composites used for cutting tools in the oil and gas industries. In particular, 25Cdiamond–70.5WC–4.5Co composites were enhanced with zirconia additives in proportions of 4 wt.% and 10 wt.% via the spark plasma sintering method. Wear tests were performed, and the analyses of elemental composition, morphology, and microstructure were completed. It was found that the addition of yttria-stabilized zirconia increased the plasticity of the matrix and thus introduced the ductile fracture mechanism, reducing the role of abrasive wear. As a result, the specific wear rate was reduced by 44% after the addition of 4 wt.% of zirconia and by 80% with 10 wt.% of ZrO2. The presence of zirconia contributed to the increase in the retention force between the matrix and diamond grits, which further reduced the intensity of the abrasive mechanism.

The paper is dedicated to the enhancement of Polycrystalline Diamond Bits (PDC) designed for oil and gas industry. A novel diamond-reinforced composite was applied for cutting inserts, with the addition of 4 wt% chromium diboride to the WC-Co matrix. The addition of CrB2 ensured improvement of bending strength and fracture toughness by nearly 30% and 40%, respectively, and enhanced the diamond retention force. The efficiency of PDC bits was further improved by incorporating constructional features in both bottomhole and reaming parts. An analytical relationship between the feeding speed and geometrical parameters was found, including the wings and calibrating inserts numbers, as well as the rotational speed of the cutter. Under the conditions of rock fracture by reaming inserts, the approximate value of the required power was calculated.

The study is devoted to structure and mechanical properties of a diamond composite used for manufacturing of cutting tools applied in a wide range of technological fields. The sample tools were fabricated by cold-pressing technology followed by hot-pressing in vacuum of the 51Fe–32Cu–9Ni–8Sn matrix mixture with diamond bits, both in absence and presence of nano-VN additives. It was demonstrated that without VN addition, the diamond–matrix interface contained voids and discontinuities. Nanodispersed VN added to the matrix resulted in the formation of a more fine-grained structure consisting of solid solutions composed of iron, copper, nickel, vanadium and tin in different ratios and the formation of a tight diamond–matrix zone with no visible voids, discontinuities and other defects. Optimal concentrations of VN in the CDM matrix were found achieving the maximum values of nanohardness H = 7.8 GPa, elastic modulus E = 213 GPa, resistance to elastic deformation expressed by ratio H/E = 0.0366, plastic deformation resistance H3/E2 = 10.46 MPa, ultimate flexural strength Rbm = 1110 MPa, and compressive strength Rcm = 1410 MPa. As-prepared Fe–Cu–Ni–Sn–VN composites with enhanced physical and mechanical properties are suitable for cutting tools of increased durability and improved performance.

This paper presents the results of the experimental research on diamond-reinforced composites with WC–Co matrices enhanced with a ZrO2 additive. The samples were prepared using a modified spark plasma sintering method with a directly applied alternating current. The structure and performance of the basic composite 94 wt.%WC–6 wt.%Co was compared with the ones with ZrO2 added in proportions up to 10 wt.%. It was demonstrated that an increase in zirconia content contributed to the intense refinement of the phase components. The composite 25 wt.%Cdiamond–70.5 wt.%WC–4.5 wt.%Co consisted of a hexagonal WC phase with lattice parameters a = 0.2906 nm and c = 0.2837 nm, a cubic phase (a = 1.1112 nm), hexagonal graphite phase (a = 0.2464 nm, c = 0.6711 nm), as well as diamond grits. After the addition of zirconia nanopowder, the sintered composite contained structural WC and Co3W3C phases, amorphous carbon, tetragonal phase t-ZrO2 (a = 0.36019 nm, c = 0.5174 nm), and diamond grits—these structural changes, after an addition of 6 wt.% ZrO2 contributed to an increase in the fracture toughness by more than 20%, up to KIc = 16.9 ± 0.76 MPa·m0.5, with a negligible decrease in the hardness. Moreover, the composite exhibited an alteration of the destruction mechanism after the addition of zirconia, as well as enhanced forces holding the diamond grits in the matrix.

It has been established that one of the main problems in the technology of the production of loose food products is the sticking of vegetables or fruits into one block. It has been proven that one of the steps to solve this problem is the use of berries, fruits, or vegetables during freezing in the form of a fluidized bed in air. However, a significant part of the energy is spent precisely when creating a fluidized bed with the help of fans. By improving the separation efficiency of small products in the freezing process, it would be possible to significantly reduce the energy costs of freezing worldwide. The purpose of this work was to determine ways to increase the efficiency of devices for freezing small products. The goal was achieved through the use of a modified method for studying energy costs, taking into account energy costs for fluidization and mechanical shaking. For comparison, two options for the efficient separation of small products during freezing were considered. Namely the separation of small products in the process of freezing with the help of fluidization, and with the help of mechanical shaking. Comparison of these variants showed that it was advisable to separate small products during freezing by mechanical shaking. It was established that their energy parameters, as well as fractional properties, are significantly different. The product temperature was determined for the case of a constant temperature of the cooling air and equipment elements. The results obtained confirmed the possibility of achieving significant energy savings of 1.5–3.5 times by using the mechanized device we proposed for freezing fruits and vegetables. The main result of this paper is the proposed method, or algorithm, for calculating energy costs for fluidization and mechanical shaking, which could be used in the design of devices for the freezing of small products; as well as the obtained data confirming the correspondence of the theoretical calculations to reality. The novelty of the research consists in presenting a model or algorithm for calculating the energy costs for fluidization and mechanical shaking. The importance of the results of the work lies in the possibility of using this technique to assess the energy effectiveness of devices for the freezing of small products.

In this single-center analysis, we evaluated the trends in 5185 hematopoietic cell transplantations performed between 1990 and 2022. The study group comprised 3237 allogeneic (alloHCT) and 1948 autologous (autoHCT) hematopoietic cell transplantations. In the multivariate analysis, there was an improvement in event-free-survival (EFS) after autoHCT (HR 0.6, 95% CI 0.4–0.7, p < 0.0001) due to reduced cumulative incidence of relapse in the last five years (56% in 2010–2014 vs. 38% in 2015–2022). An improvement in EFS after alloHCT over time was observed (HR 0.33, 95% CI 0.23–0.48, p < 0.0001), which was due to reduced non-relapse mortality. No difference in cumulative relapse incidence was observed over the last decade for allografted patients. Survival after autoHCT improved in Hodgkin’s disease (HR 0.1, 95% CI 0.1–0.3), multiple myeloma (HR 0.4, 95% CI 0.2–0.7) and solid tumors (HR 0.2, 95% CI 0.2–0.4), while after alloHCT, improvement was observed in acute myeloid leukemia (HR 0.3, 95% CI 0.1–0.5), acute lymphoblastic leukemia (HR 0.2, 95% CI 0.1–0.5), Hodgkin’s disease (HR 0.1, 95% CI 0.0–0.4), non-Hodgkin’s lymphomas and chronic lymphocytic leukemia (HR 0.2, 95% CI 0.0–0.6), inborn diseases (HR 0.2, 95% CI 0.2–0.4) and acquired aplastic anemia with matched related donors and matched unrelated donors (HR 0.3, 95% CI 0.2–0.8).

The article analyzes practical approaches to managing a portfolio of financial assets through operations with financial vehicles that allow implementing strategies with a guarantee of preserving the capital value. Development of the theory of financial assets portfolio formation in historical retrospect is analyzed, and ways of portfolio formation using scientific theories of such economists as Harry Markowitz and William Sharpe are reviewed. Classification of investment portfolios is provided, and structured instruments allowing simultaneously minimizing the risk of capital loss and increasing the potential yield of financial assets portfolio are offered on their basis. The developed recommendations on improving the management of the financial assets portfolio using structured instruments based on the conducted analysis allowed to select and adapt several real market structured instruments that made it possible both to implement the function of capital protection and form the portfolio yield at the same time.

The article analyzes practical approaches to managing a portfolio of financial assets through operations with financial vehicles that allow implementing strategies with a guarantee of preserving the capital value. Development of the theory of financial assets portfolio formation in historical retrospect is analyzed, and ways of portfolio formation using scientific theories of such economists as Harry Markowitz and William Sharpe are reviewed. Classification of investment portfolios is provided, and structured instruments allowing simultaneously minimizing the risk of capital loss and increasing the potential yield of financial assets portfolio are offered on their basis. The developed recommendations on improving the management of the financial assets portfolio using structured instruments based on the conducted analysis allowed to select and adapt several real market structured instruments that made it possible both to implement the function of capital protection and form the portfolio yield at the same time.