Total Fatigue Life Estimation Of Aircraft Structural Components Using Strain Energy Density Method

This paper is aimed at developing a suitable computation method for estimating the fatigue life of structural elements exposed to the load spectrum. The total fatigue life can be divided into two parts, until the appearance of the initial damage and the other part represents the remaining life, i.e. until the effective fracture. The conventional approach to estimating the total life requires that low-cycle fatigue characteristics of the material be used until the initial damage occurs, and dynamic characteristics of the material for the remaining life. In order to obtain a more efficient method, the Strain Energy Density (SED) method was used in this paper. The essence of this approach is to use the same low - cycle fatigue characteristics of the material to estimate the life expectancy and the remaining life. This work is focused to developing efficient computation method and software for total fatigue life of metal aircraft structural components. To obtain efficient computation method, here the same fatigue low cyclic material properties for crack initiation and crack growth are used together with finite element method (FEM) for stress analyzes. To validate quality computation methods and in-house software for fatigue life estimations computation results are compared with experiments. The results show that the predicted results agree well with the test dat

Some aspects of design ventilation system in road tunnels

In the base, working of ventilation system can be analyzed in regular and incidental modes of operation. This paper concerns the specification of the longitudinal ventilation necessary to prevent upstream movement of combustion products in a tunnel fire. In this work the objective of the study is to analyze the road way tunnel ventilation system using CFD software to create comfort ventilation system in the tunnel. The comfort ventilation concept refers to the situation when air quality within the tunnel is reduced due to presence of polluted air in the tunnel. This paper is focused on ventilation system in a road traffic tunnel in moment of accident situation as fire. In this investigation numerical simulation of fire was carried out and determination of a critical air velocity depending on the power of the fire was conducted. The output results of the software developed for this purpose, which is also used in the realization of practical projects, are shown

Anticancer Potential of Xanthohumol and Isoxanthohumol Loaded into SBA-15 Mesoporous Silica Particles against B16F10 Melanoma Cells

Xanthohumol (XN) and isoxanthohumol (IXN), prenylated flavonoids from Humulus lupulus, have been shown to possess antitumor/cancerprotective, antioxidant, antiinflammatory, and antiangiogenic properties. In this study, mesoporous silica (SBA-15) was loaded with different amounts of xanthohumol and isoxanthohumol and characterized by standard analytical methods. The anticancer potential of XN and IXN loaded into SBA-15 has been evaluated against malignant mouse melanoma B16F10 cells. When these cells were treated with SBA-15 containing xanthohumol, an increase of the activity correlated with a higher immobilization rate of XN was observed. Considering the amount of XN loaded into SBA-15 (calculated from TGA), an improved antitumor potential of XN was observed (IC50 = 10.8 ± 0.4 and 11.8 ± 0.5 µM for SBA-15|XN2 and SBA-15|XN3, respectively; vs. IC50 = 18.5 ± 1.5 µM for free XN). The main mechanism against tumor cells of immobilized XN includes inhibition of proliferation and autophagic cell death. The MC50 values for SBA-15 loaded with isoxanthohumol were over 300 µg/mL in all cases investigated. © 2022 by the authors

Ambipolar Electric Field and Potential in the Solar Wind Estimated from Electron Velocity Distribution Functions

The solar wind escapes from the solar corona and is accelerated, over a short distance, to its terminal velocity. The energy balance associated with this acceleration remains poorly understood. To quantify the global electrostatic contribution to the solar wind dynamics, we empirically estimate the ambipolar electric field (E∥) and potential (Φr,∞). We analyze electron velocity distribution functions (VDFs) measured in the near-Sun solar wind between 20.3 RS and 85.3 RS by the Parker Solar Probe. We test the predictions of two different solar wind models. Close to the Sun, the VDFs exhibit a suprathermal electron deficit in the sunward, magnetic-field-aligned part of phase space. We argue that the sunward deficit is a remnant of the electron cutoff predicted by collisionless exospheric models. This cutoff energy is directly linked to Φr,∞. Competing effects of E∥ and Coulomb collisions in the solar wind are addressed by the Steady Electron Runaway Model (SERM). In this model, electron phase space is separated into collisionally overdamped and underdamped regions. We assume that this boundary velocity at small pitch angles coincides with the strahl break-point energy, which allows us to calculate E∥. The obtained Φr,∞ and E∥ agree well with theoretical expectations. They decrease with radial distance as power-law functions with indices αΦ = −0.66 and αE = −1.69. We finally estimate the velocity gained by protons from electrostatic acceleration, which equals 77% calculated from the exospheric models, and 44% from the SERM model

The feasibility of using electromagnetic waves in determining membrane failure through concrete

Concrete flat roof defects such as water leakage present a significant and common problem in large buildings, particularly in tropical countries, where rainfall is high. To monitor this condition, effective non-destructive test methods are required to detect problems at an early stage, especially hidden defects within the concrete roof, which are critical. This paper presents the potential use of electromagnetic (EM) waves for determining possible leakage of the concrete flat roof as a result of failure of the waterproof membrane layer. This study was assessed, experimentally by investigation of the propagation of EM waves through the roof and their interaction with water. Novel Microwave sensors described in the paper operate in the 6 GHz to 12 GHz frequency range using a Marconi 6200A microwave test set. A range of existing methods was reviewed and analysed. Results of experimental tests confirmed that microwaves could be used as an alternative non-destructive method for identifying water ingress caused by membrane failure into the concrete roof surface

Magnetic field spectral evolution in the inner heliosphere

Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between $0.06 ~ \lesssim R ~\lesssim 1$ au. The spectrum is studied as a function of scale, normalized to the ion inertial scale $d_{i}$. In the vicinity of the Sun, the inertial range is limited to a narrow range of scales and exhibits a power-law exponent of, $\alpha_{B} = -3/2$, independent of plasma parameters. The inertial range grows with distance, progressively extending to larger spatial scales, while steepening towards a $\alpha_{B} =-5/3$ scaling. It is observed that spectra for intervals with large magnetic energy excesses and low Alfv\'enic content steepen significantly with distance, in contrast to highly Alfv\'enic intervals that retain their near-Sun scaling. The occurrence of steeper spectra in slower wind streams may be attributed to the observed positive correlation between solar wind speed and Alfv\'enicity.Comment: Accepted to APJ letters with minor revision

Potential use of deodorised water extracts: polyphenol-rich extract of Thymus pannonicus All. as a chemopreventive agent

Deodorised water extracts of aromatic plants are obtained as by-products of essential oil isolation and usually discarded as waste. However, phytochemical composition of these extracts encourages their further utilization as food additives or functional food ingredients. In this study we investigated phytochemical composition, antioxidant and in vivo antiproliferative activity of deodorised water extract of Thymus pannonicus All. (DWE). HPLC analysis revealed rosmarinic acid (RA) (71.11 +/- 1.54 mg/g) as the most abundant constituent of the extract, followed by salvianolic acid H (14.83 +/- 0.79 mg/g, calculated as RA). DWE exhibited pronounced antioxidant activity in vitro, in FRAP and DPPH tests (FRAP value: 7.41 mmol Fe/g and SC50: 3.80 mu g/g, respectively). Using the model of Ehrlich carcinoma cells in mice that were treated with DWE prior, at the time, and after tumour cells implantation, the tumour growth suppression and redox status of malignant cells (i.e., activities of antioxidant enzymes, level of glutathione and intensity of lipid peroxidation) were followed. DWE applied as pretreatment caused disturbance of antioxidant equilibrium as well as apoptosis/necrosis of up to 90% EAC cells. Results obtained in the present study revealed chemopreventive potential and possibility of T. pannonicus DWE usage. High content of RA and other phenolic compounds explains, at least in part, the observed effects

A Survey on the Security and the Evolution of Osmotic and Catalytic Computing for 5G Networks

The 5G networks have the capability to provide high compatibility for the new applications, industries, and business models. These networks can tremendously improve the quality of life by enabling various use cases that require high data-rate, low latency, and continuous connectivity for applications pertaining to eHealth, automatic vehicles, smart cities, smart grid, and the Internet of Things (IoT). However, these applications need secure servicing as well as resource policing for effective network formations. There have been a lot of studies, which emphasized the security aspects of 5G networks while focusing only on the adaptability features of these networks. However, there is a gap in the literature which particularly needs to follow recent computing paradigms as alternative mechanisms for the enhancement of security. To cover this, a detailed description of the security for the 5G networks is presented in this article along with the discussions on the evolution of osmotic and catalytic computing-based security modules. The taxonomy on the basis of security requirements is presented, which also includes the comparison of the existing state-of-the-art solutions. This article also provides a security model, "CATMOSIS", which idealizes the incorporation of security features on the basis of catalytic and osmotic computing in the 5G networks. Finally, various security challenges and open issues are discussed to emphasize the works to follow in this direction of research.Comment: 34 pages, 7 tables, 7 figures, Published In 5G Enabled Secure Wireless Networks, pp. 69-102. Springer, Cham, 201