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Summary: Hydrogen technologies are rapidly penetrating all aspects of life, forming the basis of the Hydrogen Civilization of the future. Hydrogenated amorphous silicon (a-Si:H) thin films are widely used in solar cells due to their advantageous optical properties. Here are some key points about their optical characteristics: 1. Optical Band Gap: The optical band gap of a-Si:H can be tuned by adjusting the hydrogen content during deposition. This allows for better absorption of sunlight and improved efficiency in solar cells. 2. Refractive Index: The refractive index of these films is crucial for designing anti-reflective coatings, which enhance the amount of light entering the solar cell. 3. Urbach Energy: This parameter indicates the width of the tail of localized states in the band gap. Lower Urbach energy values are desirable as they signify fewer defects and better electronic properties. 4. Absorption Coefficient: High absorption coefficients in the visible spectrum are essential for thinfilm solar cells to absorb maximum sunlight with minimal material. 5. Hydrogen’s Role: Hydrogenation helps in passivating dangling bonds in the silicon network, reducing defects and improving the material’s optical and electronic properties. These properties make hydrogenated amorphous silicon thin films a popular choice for cost-effective and efficient solar cells. Infrared (IR) absorption spectra are investigated hydrogenated amorphous solid solution films a-Si1-xGex: H (x = 0 ÷ 1) plasma chemical vapor deposition at different partial pressures of hydrogen PH2. Defined force, oscillator, which essentially depended on PH2. It is shown that the hydrogen contained in films mostly in the forms of GeH, SiH. Using integrated acquisitions JW, determined the amount of hydrogen in the films. Film properties depend on the composition and level of hydrogenation. The number of hydrogen atoms in films, varied by changing the composition of the gas mixture. In the work measured IR absorption for films a-Si1-xGex: H, a-Ge:H and a-Si0,88Ge0, 12: H based on films and a-Si: H and a-Si0,88Ge0, 12: H fabricated three-layer solar cells with an area of item 1.3 cm2 and efficiency equal to ~9.5%.

Summary: Parcel delivery networks have grown rapidly during the last few years due to the intensive evolution of online marketplaces. We address the issue of managing the operation of a network’s pick-up point, including the selection of the warehouse’s capacity and the policy for accepting orders for delivery. The existence of the time lag between order placing and delivery to the pick-up point is accounted for via modeling the order’s processing as the service in the dual tandem queueing system. Distinguishing features of this tandem queue are the account of possible irregularity in order generation via consideration of the versatile Markov arrival process and the possibilities of batch transfer of the orders to the pick-up point, group withdrawal of orders there, and client no-show. To reduce the probability of an order rejection at the pick-up point due to the overflow of the warehouse, a threshold strategy of order admission at the first stage on a tandem is proposed. Under the fixed value of the threshold, tandem operation is described by the continuous-time multidimensional Markov chain with a block lower Hessenberg structure for the generator. Stationary performance measures of the tandem system are calculated. Numerical results highlight the dependence of these measures on the capacity of the warehouse and the admission threshold. The possibility of the use of the results for managerial goals is demonstrated. In particular, the results can be used for the optimal selection of the capacity of a warehouse and the policy of suspending order admission.

Summary: Exactly 50 years have passed since the beginning of the active phase of hydrogen energy (since 1974). The start of hydrogen energy in the 20th century was given by the efforts of the Patriarch of hydrogen energy, Professor T. N. Veziroglu. In the early works of Professor T.N. Veziroglu, the direction of solar-hydrogen energy already appears as the cleanest energy for improving the quality of life on the planet. The development of solar energy is carried out fantastically quickly. In 2023, 428 GW of solar energy were added, which is 76% more than the same period last year, as a result of which the total installed solar capacity worldwide reached 1.6 TW. An important direction of the solar-hydrogen system is the work to increase the efficiency of solar photovoltaic panels. In this work, various parameters of films of amorphous and nanocrystalline silicon-carbon alloy (a-nc-Si1-xCx:H (x = 0–1)) doped with phosphorus (PH3) and boron (B2H6) are investigated. The properties of these films obtained on various substrates of quartz, glass and silicon with a coating of Fe, Al, Pd, Ni, Ti, Ag, are studied. The morphology of the obtained nanotubes is studied using transmission electron microscopy (TEM). The structural properties of the films are also studied using infrared spectroscopy and X-ray diffraction. Cascade solar cells with an area of S = 1.0 cm2 and an efficiency of 14.09% are created. Solar photocells made of amorphous and nanocrystalline silicon-carbon alloy currently have the highest warranty resource - up to 35 years. This allows for long-term investments in the use of land that has a low cost with high benefit. At the same time, a good basis is created for the intensive development of solar-hydrogen energy.

Summary: The asymmetric unit of the title compound, C9H20N+Br^- * C6F4I2, contains one 2,2,6,6-tetramethylpiperidine-1-ium cation, one 1,2,3,4-tetrafluoro-5,6-diiodobenzene molecule, and one uncoordinated bromide anion. In the crystal, the bromide anions link the 2,2,6,6-tetramethylpiperidine molecules by intermolecular C-H...Br and N-H...Br hydrogen bonds, leading to dimers, with the coplanar 1,2,3,4-tetrafluoro-5,6-diiodobenzene molecules filling the space between them. There is a pi-pi interaction between the almost parallel benzene rings [dihedral angle = 10.5 (2) deg] with a centroid-to-centroid distance of 3.838 (3) A and a slippage of 1.468 A. No C-H...pi(ring) interactions are observed. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H...F/F...H (23.8%), H...H (22.6%), H...Br/Br...H (17.3%), and H...I/I...H (13.8%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing.

Summary: The electrical resistance of undeformed samples hardened in water gradually increases to 300-400 °C due to the positive temperature coefficient of resistance. The progression of the curve from 400 to 700 °C indicates the development of the K-state. In the temperature range 700- 925 °C, the solid solution decomposes with the formation of particles of a strengthening phase, which leads to a decrease in electrical resistance. The rise of the curve above 950 °C is associated with the dissolution of previously released particles of the second phase. The heating curve indicates the occurrence of the mentioned processes in reverse order. In deformed samples, the formation of the K-state during heating occurs in a wider temperature range (from 100 to 700 °C) and is much more intense than in undeformed samples. The course of the cooling curve is similar to the cooling curve of samples quenched in water [1]. The cooling curve in the temperature range 775-500 °C is slightly higher than the heating curve, which is associated with different degrees of formation of the K-state due to different “initial” structures [2]. After cooling, the electrical resistance of undeformed samples cooled in a furnace returns to its original value. In deformed samples it is 5% higher than before heating, which indicates a stable influence of deformation on subsequent transformations. The magnitude of the change in electrical resistance after cooling depends on the previous treatment. For samples quenched only in water, it is 3.5% higher, for samples with a reduction of 50% - by 8.7%, for samples with a reduction of 75% - by 10.5%. This increase in electrical resistance is determined by the occurrence of the K-state during cooling, and the different magnitude of the increase is associated with the influence of the deformation energy (preserved even after high heating) on the development of the process of formation of the K-state during cooling. An increase in the electrical resistance of samples cooled with the furnace from the quenching temperature is observed only up to 550 0C, regardless of whether the samples were subjected to work hardening or not, and this increase is significantly less than that of the same samples, but quenched in water [1, 3]. When cooling with the furnace from the quenching temperature, some development of the K-state already occurs in the samples, which is probably not completely destroyed even with a reduction of 50%. This determines a smaller increase in electrical resistance during subsequent heating and shifts the maximum to a temperature of 550 °C [2, 5]. In addition, a distinctive feature of the heating curves of the samples is a two-stage drop in electrical resistance in the temperature range of 550-950 °C.

Summary: The presented paper is devoted to the solution of cylindrical free oscillation problems of a rectangular plate, taking into account the resistance of the external environment. In the title of the article, accepting a cylindrical oscillation is not chosen randomly and it is a rare issue in the theory of plates and coatings, therefore, the solution of the considered problem is new and relevant. In this paper, the influence of the external environment is considered viscoelastic according to the Voigt model, the plate is assumed to be rectangular, thin-walled, and orthotropic, being heterogeneous along its length (i.e., in the direction of the large side). The conditions for fixing the contours of the plate are chosen in such a way that a heterogeneous boundary condition is obtained, otherwise the shape of the free oscillation cannot be cylindrical. Under the required conditions, the oscillation equation of the plate is formulated, and as a result, the fourth order partial differential equation with a variable coefficient is obtained. The obtained equation is a complicated enough equation modified from the Sophie-Germain equation written for the deflection of the plates according to the condition of the problem, and it is hard to be solved. Such equations do not have an analytical solution, and for now the most rational method for its solution is considered to be Bunov Galerkin's method of orthogonalization and separation of variables. In order to calculate the value of the frequency of the oscillation, the relationship equations were obtained, the calculations were carried out for cases where the characteristic functions change with a linear law, and the material of the plate is homogeneous and heterogeneous. Equations of dependence between dimensionless frequency and characteristic functions and parameters characterizing a heterogeneous viscoelastic base were obtained. An error function was constructed for the obtained equation and the orthogonalization condition was checked with the help of the error function. In order to compare the solution of the problem, the frequency analysis of the plate was carried out using the finite element method, for which the frequency analysis was carried out in 6 frequency cases on plates with different length dimensions. Solidworks software was used here. The results were presented in form of graphs and tables.

Summary: The test research facility, in which the properties of warm water “Khachmaz” (p,ρ,T) in Khachmaz area, Examined was Azerbaijan which has air conditioning and a constant temperature of T=293.15 K.Data from various sources were compared with the results obtained for the watery arrangement of water, toluene, and NaCl (m=2.96661 mol·kg-1). The gotten comes about are displayed graphically within the figures. In article, the reliance of the thickness of Khachmaz warm water of the Khachmaz locale of Azerbaijan on the temperature of ρ/(kg ∙ m-3) was measured within the high-precision temperature extend T = (278.15-468.15) in a tubular densimeter 5000M Anton-Paar DSA. Utilizing exploratory values at chosen temperatures, expository connections of warm water were set up. The gotten values are depicted by numerical conditions.

Summary: Friction brakes generate braking torque through the friction force between rotating (disk, drum) and non-rotating (pad, band) components. Drum-type brakes are primarily used in heavy-duty vehicles. To initiate braking, the shoe is pressed against the drum, creating contact pressure between the pressed surfaces. Tangential stresses arising from drum rotation produce the braking torque. The braking torque in the brake mechanism depends on the contact pressure and the coefficient of friction between the compressed surfaces. With a large compressive force, the deformations of the drum and shoe differ, altering the drum's round cross-section and causing variations in braking force at different moments. Therefore, accurately determining contact pressure is crucial for drum brakes. This article focuses on calculating braking torque by determining the deformations of the mold as close to real-world conditions as possible.

Summary: The article provides information on the creation and study of energy systems based on the power of air flows with maximum use of advantages in processes associated with nature. An analysis of available data in this area is carried out, the advantages and disadvantages of energy installations are indicated. Based on the analysis and theoretical considerations, the indicators of the model for improving the energy system using the power of the air flow, including economic efficiency, are analyzed. Changes in influencing parameters to improve the efficiency of using the design of the energy installation are described, a comparative analysis is given.

Summary: Thermomechanical processing is a combination of the operations of deformation by heating and cooling (in different sequences), as a result of which the formation of the final structure of a metal alloy, and consequently its properties, occurs under conditions of increased density and the corresponding distribution of structural imperfections created by plastic deformation. Therefore, firstly, research in the field of thermomechanical processing is reduced to studying the effect of plastic deformation on transformations in heat-treated alloys and on the structure in properties after these transformations. Secondly, thermomechanical processing is advisable in all cases where heat treatment of metal alloys is effective. Phase transitions during heat treatment and plastic flow occur as a result of the restructuring of the same atoms, connected not only by general regular structures, but also by certain, also to a certain extent regular, deviations from these structures, the main ones of which are dislocations.