Phenomenological Models and Peculiarities of Evaluating Fatigue Life of Aluminum Alloys Subjected to Dynamic Non-Equilibrium Processes

Physical-mechanical models for predicting the fatigue life of aluminum alloys D16ChATW and 2024-T351 are proposed and tested. Damage accumulation patterns are established for these alloys in the initial state and after dynamic non-equilibrium processes (DNP) of different intensity that occur at maximum cycle stresses σmax from 340 to 440 MPa, cycle asymmetry coefficients R = 0.1 and load frequency f = 110 Hz. The main model parameters are the initial alloy hardness HV and the limiting parameters of scatter of hardness values m. These parameters are evaluated in the process of cyclic loading with fixed maximum stresses of the cycles. Relative values me are also considered. For the alloys in the initial state, the proposed models are shown to be in good agreement with the experimental results. Conversely, structural changes taking place in alloys after DNP complicate the prediction of their fatigue life.

Simulation and Field Campaign Evaluation of an Optical Particle Counter on a Fixed-Wing UAV

Unmanned aerial vehicles (UAVs) have great potential to be utilised as an airborne platform for measurement of atmospheric particulates and droplets. In particular, the spatio-temporal resolution of UAV measurements could be of use for the characterisation of aerosol, cloud, and radiation (ACR) interactions, which contribute to the largest uncertainty in the radiative forcing of climate change throughout the industrial era (Zelinka et al., 2014). Due to the infancy of the technique however, UAV-instrument combinations must be extensively validated to ensure the data is of high accuracy and reliability. This paper presents an evaluation of a particular UAV-instrument combination: the FMI-Talon fixed-wing UAV and the UCASS open-path optical particle counter. The performance of the UCASS was previously evaluated on a multi-rotor airframe by Girdwood et al. (2020). However, fixed-wing measurements present certain advantages—namely endurance, platform stability, and maximum altitude. Airflow simulations were utilised to define limiting parameters on UAV sampling—that is, an angle of attack limit of 10° and a minimum airspeed of 20 ms−1—which were then applied retroactively to field campaign data as rejection criteria. The field campaign involved an inter-comparison with reference instrumentation mounted on a research station, which the UAV flew past through stratus cloud. The effective diameter measured by the UAV largely agreed within 2 μm. The droplet number concentration agreed within 15 % on all but 5 profiles. It was concluded that UCASS would benefit from a mechanical redesign to avoid calibration drifts, and UAV attitude variations during measurement should be kept to a minimum.

Technical and Economic Feasibility Study for Implementing a Novel Mooring-Assisting Methodology in Offloading Operations Using Autonomous Unmanned Aerial Vehicles

Summary As oil and gas exploration goes toward deeper fields in the Brazilian industry scenario, offloading operations emerge as the most viable option to drain production. However, these operations demand expensive resources, such as shuttle tankers and support boats; operational risks, which despite being managed, limited, and mitigated to be as low as reasonably possible, are still present in some stages (i.e., ship’s approximation to the oil rig, mooring, hose connection, and so forth); and environment limiting parameters (i.e., wave height, surface-current direction, wind speed and direction, and so forth). Therefore, in this paper, we propose using unmanned aerial vehicles (UAVs) in an autonomous mode to carry out the messenger line from the shuttle tanker to the floating, production, storage, and offloading (FPSO) unit or the floating storage and offloading unit (FSO) instead of line-handling (LH) boats (for conventional operations that use those resources) or the messenger-cable-launching guns (for dynamic positioning operations). This represents a viable alternative solution to reducing costs and risks in these tasks and a possibility to eliminate some meteorologic and oceanographic limiting conditions to operations, because the UAV will be susceptible only to wind conditions, and not to sea and visibility conditions, like LHs are. We present the simulated results of the proposed methodology using a robotic operating system (ROS) and the economic gain [derived from cash-flow-cost reducing of operations, payoff time of the investment, net present value (NPV), and internal rate of return] of applying this technology, evaluating its use in a realistic scenario based on a real deepwater oil field in Brazil. The developed controller behaves very well, and simulations showed robust results. In addition, the economic study presents the proposal’s attractiveness.

Simple mathematical modelling approaches to assessing the transmission risk of SARS-CoV-2 at gatherings

Background: Gatherings may contribute significantly to the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this reason, public health interventions have sought to constrain unrepeated or recurrent gatherings to curb the coronavirus disease 2019 (COVID-19) pandemic. Unfortunately, the range of different types of gatherings hinders specific guidance from setting limiting parameters (e.g. total size, number of cohorts, the extent of physical distancing). Methods: We used a generic modelling framework, based on fundamental probability principles, to derive simple formulas to assess introduction and transmission risks associated with gatherings, as well as the potential efficiency of some testing strategies to mitigate these risks. Results: Introduction risk can be broadly assessed with the population prevalence and the size of the gathering, while transmission risk at a gathering is mainly driven by the gathering size. For recurrent gatherings, the cohort structure does not have a significant impact on transmission between cohorts. Testing strategies can mitigate risk, but frequency of testing and test performance are factors in finding a balance between detection and false positives. Conclusion: The generality of the modelling framework used here helps to disentangle the various factors affecting transmission risk at gatherings and may be useful for public health decision-making.

Calculating of dumps stability laying on weak gently dipping interface

Relevance of the research. Stable parameters of dumps are critical in mining operations ensuring their safety and economic efficiency. This problem is particularly acute for mining enterprises engaged in surface mining and for coal open pit mines, in particular. One of the main problems of this issue is related to the substantiation of rigorous methods for assessing stability and determining the limiting parameters of external and internal dumps filling an embankment on weak gently dipping interface. In the technical and regulatory literature, this issue has been considered for a long time. However, there are no specific recommendations for finding the most dangerous sliding surfaces on slopes, as well as methods for calculating shearing and restraining forces along these surfaces. All the signs are that the reason for the stability loss of operated dumps is the absence of theoretically substantiated design schemes, respectively, there are errors in the design of dumping. Purpose of the work is to develop reliable methods for calculating the limiting parameters of dumps on weak gently dipping interface. The main idea of the work is to apply a new, not previously used scheme for calculating the stability of dumps on weak gently dipping interface. Research methods. The work deals with the apparatus of flow mechanics and more specifically, the rigid-plastic model (the method of limit equilibrium), and the variational, integral and differential branches of calculus act as a mathematical apparatus. Results and conclusions. Based on the results of previous studies, a new scheme for calculating the stability of the dump during its destruction along weak interface was proposed, which implies the absence of a curved section of the sliding surface under the slope and the convex shape of the sliding surface under the berm. In contrast to the existing calculation schemes, such a calculation scheme predicts significantly lower values of the critical parameters of dumps. It means that the use of the proposed scheme will prevent the destruction of dumps by landslides along the dumpbasement interface and increase the economic efficiency of enterprises. Because a sufficiently large overestimation of the critical parameters of dumps at weak interface limited by current regulatory documents has been determined, it is recommended to revise these parameters for the designed and operated dumps using the proposed schemes for calculating their stability.

Intensification the Features of Interaction Between Components of Pollutants of Industrial Waste Waters with Modified Zeolites Based on the Results of Integrated Physical and Chemical Researches

The results of a study on the adsorption of oil products and heavy metal ions by modified zeolites from industrial wastewater are presented. As a modifier of zeolites of the Holinsky deposit, a sulfur polymer is proposed that is obtained from waste during the production of epichlorohydrin, the main components of which is 1,2,3-trichloropropane. The mechanisms of adsorption and the results of investigations by the methods of infra-red pectroscopy and energy differential X-ray spectroscopy of the initial samples of materials are described in detail. On the Irspectres new absorption bands are considered. These bands reflect the nature of fixation of modifier on the surface of sorbent. Also the results of original investigations of the thermodynamic laws of sorption extraction of Ni2+, Zn2+, Cu2+ from wastewater are presented. The limiting parameters of the adsorption process are described by the Langmuir equation. The graphical method the limiting value of adsorption, the adsorption equilibrium constant, the differential heat of adsorption, the adsorption rate constant, the activation energy, the Gibbs energy was founded. It is proved that the investigated processes obey the laws of physical adsorption and are spontaneous.

Classification of parameters of innovative projects in the framework of digital transformation programs for sustainable development of industrial enterprises

The task of determining the parameters of an innovative project, their composition and structure is a crucial stage in the design and development of an innovative project within the framework of digital transformation. A refined classification of the parameters of an innovative project, considering the specifics of projects aimed at digital transformation of the enterprises, operating in the manufacturing sector, is proposed. The classification separates the parameters of innovative projects into 2 key categories: target parameters and controlled or limiting parameters. When applied to innovative project parameters in digital transformation, target parameters are further divided into gradual and optional types; controlled or limiting parameters constitute basic structure of innovative projects and include road-map and time allocation, costs, market parameters, human resources, technological readiness, regulatory norms. The presented approach leaves room for further research based on additional real case data and risk evaluation, standard and accepted deviations of the project results analysis.