Photovoltaic characteristics of structures with porous silicon obtained by various technological plans

In this work, the influence of technological parameters on the current-voltage characteristics of solar cells with porous silicon is investigated. It is shown that for photosensitive structures with a porous layer, the optimal mode is pore formation by electrochemical etching followed by diffusion. The effect of etching modes affects the character of the photosensitivity curve.

Deposition of a titanium carbonitride coating by magnetron sputtering on a substrate with a potential voltage

Titanium carbonitride (TiCN) is of high relevance in the field of creating wear-resistant protective coatings in order to ensure maximum wear resistance and service life of parts of friction units. Titanium carbonitride coatings were obtained by magnetron sputtering at various bias substrate in the range from 0 to -130 V with a step of 10 V. The effect of the bias substrate on the deposition rate, phase and elemental composition, and the friction coefficient of the obtained coatings was investigated. As a result of the obtained dependences, the most optimal mode of deposition by the method of reactive magnetron sputtering with a negative bias voltage on the substrate was determined.

Feasibility and design of a trial regarding the optimal mode of delivery for preterm birth: the CASSAVA multiple methods study

Background Around 60,000 babies are born preterm (prior to 37 weeks’ gestation) each year in the UK. There is little evidence on the optimal birth mode (vaginal or caesarean section). Objective The overall aim of the CASSAVA project was to determine if a trial to define the optimal mode of preterm birth could be carried out and, if so, determine what sort of trial could be conducted and how it could best be performed. We aimed to determine the specific groups of preterm women and babies for whom there are uncertainties about the best planned mode of birth, and if there would be willingness to recruit to, and participate in, a randomised trial to address some, but not all, of these uncertainties. This project was conducted in response to a Heath Technology Assessment programme commissioning call (17/22 ‘Mode of delivery for preterm infants’). Methods We conducted clinician and patient surveys (n = 224 and n = 379, respectively) to identify current practice and opinion, and a consensus survey and Delphi workshop (n = 76 and n = 22 participants, respectively) to inform the design of a hypothetical clinical trial. The protocol for this clinical trial/vignette was used in telephone interviews with clinicians (n = 24) and in focus groups with potential participants (n = 13). Results Planned sample size and data saturation was achieved for all groups except for focus groups with participants, as this had to be curtailed because of the COVID-19 pandemic and data saturation was not achieved. There was broad agreement from parents and health-care professionals that a trial is needed. The clinician survey demonstrated a variety of practice and opinion. The parent survey suggested that women and their families generally preferred vaginal birth at later gestations and caesarean section for preterm infants. The interactive workshop and Delphi consensus process confirmed the need for more evidence (hence the case for a trial) and provided rich information on what a future trial should entail. It was agreed that any trial should address the areas with most uncertainty, including the management of women at 26–32 weeks’ gestation, with either spontaneous preterm labour (cephalic presentation) or where preterm birth was medically indicated. Clear themes around the challenges inherent in conducting any trial emerged, including the concept of equipoise itself. Specific issues were as follows: different clinicians and participants would be in equipoise for each clinical scenario, effective conduct of the trial would require appropriate resources and expertise within the hospital conducting the trial, potential participants would welcome information on the trial well before the onset of labour and minority ethnic groups would require tailored approaches. Conclusion Given the lack of evidence and the variation of practice and opinion in this area, and having listened to clinicians and potential participants, we conclude that a trial should be conducted and the outlined challenges resolved. Future work The CASSAVA project could be used to inform the design of a randomised trial and indicates how such a trial could be carried out. Any future trial would benefit from a pilot with qualitative input and a study within a trial to inform optimal recruitment. Limitations Certainty that a trial could be conducted can be determined only when it is attempted. Trial registration Current Controlled Trials ISRCTN12295730. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 61. See the NIHR Journals Library website for further project information.

Evaluation of the Effect of Sizing Compositions on the Properties of Hydrated Cellulose Technical Yarn

The influence of sizing compositions on the reinforcing properties of hydrated cellulose technical yarns has been investigated. The optimal mode of modification of hydrated cellulose yarns has been determined. The evaluation of the structural properties of the modified yarns has been carried out. The kinetic features of the modified yarns wetting by an epoxy oligomer have been studied.

Determining the Optimal Mode of the Inconel 718 Alloy Deposition at a Direct Laser Deposition Plant

The paper describes determining the optimal direct laser deposition mode when processing the results of a two-factor experiment by the steep ascent method. The dependence of the ultimate tensile strength on the volumetric energy density and the lateral pitch was chosen as the target function.

Use of Spectroscopy and Computer Simulation to the Study of Surfaces Modified by Ionic Implantation

Using X-ray Photoelectron Spectroscopy (XPS) and energy dispersion spectrometry, the phase and elemental compositions of the nanoscale surface layer of implants are studied. The method of determination of the optimal mode of nanoscale modification of the surfaces of metals and alloys by means of the ionic implantation is presented. The problem of processing the curved surfaces with mathematical calculations and a computer simulation is solved. The proposed technique is tested on synthesized implants. The sample hardness was taken as a criterion.

Choice of the optimal mode of control of the process of emergency landing of an unmanned quadcopter

Peculiarities of the process of emergency landing of an unmanned quadcopter have been studied by mathematical modeling. The method of landing an unmanned quadcopter in case of failure of one of the four pairs of electric motor-propeller is proposed. The basis of this technique is the application of the parachuting effect. Parachuting is achieved by forcibly turning off the power of the motor, which is located at the opposite end of the same traverse as the faulty motor. As a result, the vertical speed of the unmanned quadcopter at the time of landing is significantly reduced and approaches a relatively safe value.

Energy dose of sunflower seed treatment in a magnetic field

Pre-sowing treatment of sunflower seeds in a magnetic field makes it possible to improve the sowing quality of seeds and increase the yield of sunflower without the use of mineral fertilizers and chemical plant protection products. Compared to other electrophysical methods, pre-sowing treatment of seeds in a magnetic field is a highly productive, energy-consuming, safe method for operating personnel and the environment. It has now been established that the yield and biometric indicators of agricultural crops depend on the dose of magnetic treatment. Therefore, the aim of the study was to determine the optimal energy dose for processing sunflower seeds in a magnetic field. An analytical expression has been obtained for determining the energy dose of sunflower seed treatment in a magnetic field. It contains all the operating parameters of seed treatment in a magnetic field. It has been established that the energy dose of sunflower seeds treatment in a magnetic field depends in direct proportion to the square of the magnetic induction and pole division and inversely to the speed of the seeds in the magnetic field. The carried out multifactorial experiment made it possible to determine the sunflower seeds germination energy and germination at various energy doses of treatment. This made it possible to determine the optimal mode of sunflower seeds treatment in a magnetic field. It was found that the optimal mode of pre-sowing treatment of sunflower seeds in a magnetic field is a magnetic induction of 0.065 T, four-fold re-magnetization, pole division 0.23 m, a seed velocity of 0.4 m/s, providing an energy treatment of 3.8 J‧s/kg. With the optimal treatment of sunflower seeds in a magnetic field, the germination energy increased by 28 %, the germination – by 24 %, and the yield – by 26 %. Key words: sunflower, pre-sowing treatment, magnetic field, magnetic induction, pole division, velocity of seed movement, energy dose of treatment