Definite Conditions Research Articles

О корректировке алгоритма расчета высоты сортировочной горки

At present the height of marshalling yards is calculated basing on the determination of the power of resistance to the movement of cars when rolling down a hill on definite conditions. Wherein the calculation norms of the main specific resistance to movement, used until present time, were accepted more than 40 years ago. Therefore, their use for the description of the modern car park driving characteristics may lead to the results of unsuitable current operating conditions, as well as to the increase of the emergency appearance when disbanding. The article suggests the adjustment of the algorithm of a marshalling yard height calculation based on the results of up-to-date researches of the main specific resistance to movement made by the specialists of the Siberian Transport University and JSC «NIIAS» and the correction of the methods of calculation of the height of the marshalling yard.

Optimization Method for Grading Civil Aircraft Cabin Space Under Airworthiness Regulations

In the confined space of civil aircraft cabins with limited length and height, achieving a rational and efficient utilization of cabin space through the reasonable layout of cabin facilities, spatial allocation of seats, and equipment facilities is an important means to enhance the competitiveness of the civil aviation market, drawing significant attention from airlines. This paper proposes a graded optimization method for cabin layout that meets airworthiness regulations. By balancing and optimizing the requirements definition, influencing factors, and design conditions of cabin layout design, the method achieves an optimized arrangement of simulated cabins, ensuring both economic efficiency and improved passenger comfort. It provides valuable guidance for the cabin layout of civil aircraft and the redesign of in-service aircraft cabins.

Establishing definitive conditions for global centers in generalized polynomial Liénard systems

Establishing definitive conditions for global centers in generalized polynomial Liénard systems

Hierarchical stability conditions for linear systems with interval time-varying delay

This paper proposes the hierarchical stability conditions for linear systems with an interval time-varying delay. In the matter of the delay, the upper and lower bounds are restricted, but there is no constraint on its derivative. Firstly, based on the state vectors and multiple integral state vectors involved in the delay-related generalized free-matrix-based integral inequalities (GFIIs), the hierarchical Lyapunov-Krasovskii functional (LKF) candidates are constructed. Then, the GFIIs are applied for the approximation of the integral quadratic terms, which will introduce the delay related nonlinear terms in the LKF differential. Next, the novel adjusted matrix-valued high and odd degree polynomial negative definite conditions (NDCs) are provided to acquire the hierarchical linear matrix inequality (LMI) conditions and cope with the nonlinear terms introduced by the GFIIs. Eventually, the advantages of the obtained stability conditions are checked through some numeric examples.

Application of Proxy Minerals for Evaluation of the Oxygen Isotope Composition of Felsic Melts

The problems associated with the use of quartz and zircon as proxy minerals for the reconstruction of δ18O values in acidic melts are considered. It is shown that the correction values Δ(Qz–R) and Δ(R–Zrn) used for the reconstructions are not strictly constant and depend on the mineral composition of the rock and the closure temperature of the oxygen isotopic system of the proxy mineral (Tq, Tz–closure temperature of quartz and zircon, respectively). The applicability of quartz was estimated using an equation for Δ(Qz–R) calculation, which takes into account Tq and the mineral composition of rocks. Using the leucogranites of the Raumid massif (South Pamirs) as an example, it was shown that this correction can be approximated by constant value only under definite conditions. The value of Δ(R–Zrn) was estimated using approach based on calculating the weighted average fractionation coefficient and independent estimates Tz using a zirconium thermometer. It was shown for leucogranite porphyries of the Omsukchan trough that this correction for identical rocks varies from 1.3 to 1.9 ‰, unlike Δ(R–Zrn) = 2.1 determined by the dependence on the SiO2 content (Lackey et al., 2008). The advantages and limitations on the application of quartz and zircon as proxy minerals have been analyzed.

Improved Stability Analysis Results of Generalized Neural Networks With Time-Varying Delays.

This article studies the stability problem of generalized neural networks (GNNs) with time-varying delay. The delay has two cases: the first case is that the delay's derivative has only upper bound, the other case has no information of its derivative or itself is not differentiable. For both two cases, we provide novel stability criteria based on novel Lyapunov-Krasovskii functionals (LKFs) and new negative definite conditions (NDCs) of matrix-valued cubic polynomials. In contrast with the existing methods, in this article, the proposed criteria do not need to introduce extra state variables, and the positive-definite constraint on the novel LKF is relaxed. Moreover, based on free-matrix-based inequality (FMBI) and new NDCs, the stability conditions are expressed as linear matrix inequalities (LMIs). Eventually, the merits and efficiency of the proposed criteria are checked through some classical numerical examples.

Some Fixed-Point Results in Extended S-Metric Space of Type (α,β)

In this paper, we introduce the notion of extended S-metric space of type (α,β). This extension is a generalization of S-metric space, defined by employing two functions instead of considering a constant in the second condition of the S-metric space definition. Accordingly, we prove some fixed-point results and give some examples to illustrate the validity of our work, along with giving an application of the Fredholm integral equation.

Novel stability criteria of generalized neural networks with time-varying delay based on the same augmented LKF and bounding technique

This paper researches the stability issue of generalized neural networks (GNN) with time-varying delay. For the delay, its derivative has an upper bound or is unknown. Firstly, the augmented Lyapunov-Krasovskii functional (LKF) is constructed based on the state vectors of the third order integral inequalities. Then, by introducing two sets of state vectors, the LKF derivative is presented as the quadratic and quintic polynomials of the delay, respectively. Next, the new quadratic and quintic polynomial negative definite conditions (NDCs) are proposed to set up the linear matrix inequalities (LMIs). In addition, based on the same LKF and third order integral inequalities, this paper proves that the introduction of extra state vectors increases the conservatism of the derived stability conditions. Eventually, the advantages of the provided conditions are illustrated by several numerical examples.

Insights on the mechanism of bleomycin to induce lung injury and associated in vivo models: A review.

Acute lung injury leads to the development of chronic conditions such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), asthma as well as alveolar sarcoma. Various investigations are being performed worldwide to understand the pathophysiology of these diseases, develop novel bioactive compounds and inhibitors to target the ailment. Generally, in vivo models are used to understand the disease outcome and therapeutic suppressing effects for which the animals are chemically or physically induced to mimic the onset of definite disease conditions. Amongst the chemical inducing agents, Bleomycin (BLM) is the most successful inducer. It is reported to target various receptors and activate inflammatory pathways, cellular apoptosis, epithelial mesenchymal transition leading to the release of inflammatory cytokines, and proteases. Mice is one of the most widely used animal model for BLM induced pulmonary associated studies apart from rat, rabbit, sheep, pig, and monkey. Although, there is considerable variation amongst in vivo studies for BLM induction which suggests a detailed study on the same to understand the mechanism of action of BLM at molecular level. Hence, herein we have reviewed various chemical inducers, mechanism of action of BLM in inducing lung injury in vivo, its advantages and disadvantages. Further, we have also discussed the rationale behind various in vivo models and recent development in BLM induction for various animals.

Health Science Research at a Regional Level: Insights From South America Comment on "The Roles of Regional Organisations in Strengthening Health Research Systems in Africa: Activities, Gaps, and Future Perspectives".

The article seeks to shed light on the role of regional organizations in strengthening health research systems in Africa, how they operate and how they work, as well as debts and future challenges. As can be observed also in South America, the continued strengthening of health research requires strategic thinking about the roles, comparative advantages, and capacity of regional organizations to facilitate the flourishing of health research systems. Health research is a strategic field for the transformation of socio-health inequalities on the one hand and the reduction of regional asymmetries on the other. Thus, regional organizations represent key actors in strengthening health research systems and the regional research agenda reinforces its sovereign condition in the autonomous definition of relevant topics and financing. In this process, integration mechanisms face a great challenge, as shown by the recent pandemic, not only in Africa but also in South America.

ADORNMENTS AND ARMS FROM THE EARLY MEDIEVAL SITES IN SUMY REGION: COMPILING THE CATALOG OF FINDINGS

The paper contains information about Early Medieval jewelry and parts of bladed weapons from the Sumy region, discovered in the sites and assemblages of the Penkivka and Kolochyn cultures. In total, the information on seven points was collected where twenty four finds occurred. The conditions of finding, typological definition and circle of analogies are determined. These materials supplement the information about the Early Medieval hoards of the Martynivka circle from the Sumy region which were given to the storages of the museums.
 Adornments from Kolochyn culture presented by finds from Velyki Budky hillfort and settlement, Bezdryk barrow cemetery, Krasne 4 and Mala Rybytsia settlements. There are also two burials with jewe­lry of «antiquities of the Ants circle» known in Sumy region: Berezivka and Riabivka 3. Decorations from Penkivka culture presented by finds from Riabivka 3. All finds presented by radiate-headed fibulas, bracelets, belt sets and beads.
 Parts of bladed weapons presented by two cross-guards from Kolochyn culture sites — hillfort Velyki Budky and settlement Krasne 4.
 These finds either belong to the early stages of the existence of Early Medieval Slavic antiquities or find analogies among the decorations characteristic of the hoards of the Martynivka circle. Finds from the Krasne 4 settlement (buckle and cross-guard) and cross-guard from the Velyki Budky settlement belong to the early stage of the Kolochyn culture. The burial from Berezivka can be dated to the late 6th century, and the burials from Riabivka 3 to the second half of the 7th century. Most of the individual adornments have analogies among the decorations characteristic of the hoards of the Martynivka circle. Jewelry from these hoards dates from the second half of 6th — the late 7th century. And deposition into the earth occurs in the middle — third quarter of the 7th century.

Alloying bulk-immiscible metals at the nanoscale: An XPS/STM study of bimetallic Ag-Pt/HOPG nanoparticles

The intentional tailoring of surface structure in bimetallic nanoparticles is of high interest for academic research and industry, and many attempts have been made to improve the control over the distribution mode of the constituent elements which ranges from homogeneously mixed nanoalloys to core–shell nanostructures. However, some metal combinations exhibit a wide miscibility gap in the bulk, which nonetheless could be overcome under definite conditions at the nanoscale due to size effects. Here we present the detailed XPS/STM investigation of alloying capability of bulk-immiscible metals on the example of the Ag-Pt/HOPG bimetallic system prepared by thermal vacuum deposition. We found out that partial alloying of Ag and Pt occurs already at the preparation stage, and the following thermal annealing of the Ag-Pt/HOPG samples at 300–400 °C does not help to enhance the alloying degree owing to thermodynamically driven surface segregation of silver. Increasing the annealing temperature ruins the structure of Ag-Pt bimetallic nanoparticles due to silver sublimation, while even longer annealing time leads to partial phase separation. Our results demonstrate a limited alloying capability of Pt and Ag at the nanoscale which will be relevant for further research on the design and functioning of bimetallic catalysts containing bulk-immiscible metals.

Performance evaluation of in situ Fenton-mediated photocatalysis of industrial dye effluent with enhanced TiO2 nanoparticle

Abstract Effluents resulting from the frequent use of industrial azo dyes in textile operations have posed great toxicological impacts on man and the environment. The limitations of conventional treatment infrastructure necessitate the use of rapid Fenton-mediated catalytic systematic process to tackle the attendant treatment limitations. The study applied in situ Fenton-mediation process with constructed low power UV-LED reactor for rapid catalytic treatment of dye-laden effluent using enhanced acid and alkali TiO2-nanoparticles (Nps) (1–5%, i.e. 1–5 M) at definite experimental conditions, respectively. A comprehensive instrumental study was done to access the morphological, functional and elemental constituents of these nanocatalysts. The performance of the respective catalyst was evaluated using methylene blue (MB) dye at definite experimental conditions of pH, dosage, concentration and irradiation time. The results revealed a mesoporous structural nanocatalyst with increasing surface area after enhanced modification. The optimal experimental conditions of pH and concentration were recorded as 5 and 10 mg/L, respectively; while the most efficient nanocatalyst was 3 wt% alkali-modified TiO2 (3% Ak-TiO2) having a degradation efficiency of 89.15% at 90 min of irradiation using 50 mg dosage in contrast to higher irradiation time and catalyst dosage for other catalysts.

Quantum thermodynamics in nonequilibrium reservoirs: Landauer-like bound and its implications

We study quantum thermodynamics in nonequilibrium reservoirs (NERs) that are prepared from initially thermal ones via unitary driving processes. Based on the formulation of entropy production in NERs, we establish a Landauer-like bound and show that the bound can be violated under a definite condition depending on the states of NERs. It is found that the breakdown of this Landauer-like bound implies occurrences of several anomalous phenomena in NERs, namely, the efficiency enhancement of quantum thermal machines beyond the Carnot limit, the extraction of work from a single reservoir, and the spontaneous heat flow from a cold reservoir to a hot one. The results are illustrated through a physical model taking the preparation processes of NERs into account. Our work sheds light on the reason and condition of some unusual phenomena occurring in NERs and is helpful for one to prepare effective NERs that can be used as quantum resources to realize certain thermodynamic tasks.

Mean stress tensor of discrete particle systems in submerged conditions

The mean stress tensor is essential to investigate the dynamics of granular material. In this paper, we use Hamilton’s principle of least action to derive the averaged stress tensor of discrete granular assemblies subjected to hydraulic force fields, as well as rigorous conditions for a proper definition of the Representative Volume Element (RVE). The main goal behind our efforts is to upscale particle physics into a sound stress tensor for systems involving the complex interaction between grains and water. We identify the contributions from the unbalanced forces, hydraulic forces, gravity, external forces, and particle fluctuation to the mean stress tensor. In doing so, it is convenient to separate the influence of different force fields when the granular system is subjected to complex environments, e.g., subaqueous conditions. The obtained formula is then validated by triaxial test simulations of dry and saturated granular systems using the Discrete Element Method (DEM) and the Lattice-Boltzmann Method (LBM). The results show that the deduced formula can accurately calculate the stress tensor of discrete assemblies with various body-force fields. We used validated DEM-LBM simulations of submerged granular column collapses to explore the physics happening at the grain scale with this mathematical formalism and showcase its potential. We provide a new perspective based on the granular assembly scale to pursue the fluid–solid interaction. Due to the importance of stress analysis in the constitutive modeling of granular materials, this work could help to better obtain the stress–strain relationship of saturated or submerged granular systems.

Novel stability analysis methods for generalized neural networks with interval time-varying delay

This paper deals with the stability analysis of generalized neural networks (GNN) with interval time-varying delay, and some novel stability criteria are proposed. For the delay, more specifically, it has the upper and lower bounds but the information of its derivative is unknown (or itself is not differentiable). Firstly, a new Lyapunov-Krasovskii functional (LKF) is constructed to obtain the less conservative stability results. Then, in order to cooperate with the introduced LKF, the free-matrix-based inequality (FMBI) is employed in the estimation of the integral quadratic terms. Next, by utilizing the new negative definite conditions (NDCs) of matrix-valued cubic polynomials, the stability conditions are presented in the form of linear matrix inequalities (LMIs). In addition, in the establishment process of these conditions, no extra state variables are introduced and the positive definite constraint on the LKF is relaxed. Finally, the validity and advantages of the proposed conditions are illustrated with some classical numerical examples.

Potential of Ecological Benefits for the Continuous Flow Intersection

Energy conservation and emission reduction from the transportation sector are of great significance in coping with the global energy and environmental crisis. As the bottleneck of urban road traffic, intersection burdens the urban environment greatly. When the volume of left-turn traffic is large, the continuous flow intersection (CFI) can effectively improve intersection operation efficiency. This paper first put forward the definition and application conditions of CFI. Then its mechanism for energy saving and emission reduction was analysed. CFI transformation was designed taking a typical intersection in Xi’an as an example. Operating efficiency, energy consumption and emissions of the intersection before and after CFI transformation were evaluated using the VISSIM model. The results show that energy consumption and emissions in the intersection are greatly reduced after CFI transformation. Queue length is reduced by more than 41%. Energy consumption and pollutant emission are reduced by about 8%. Through the simulation analysis, the emission reduction benefits most when the volume of left-turn traffic is 80%–85% of the design capacity, and the ratio of leftturntraffic over through traffic is maintained between 50% and 100%. This study suggests that CFI is suitable for large-scale promotion with careful examination.

A new approach to analyzing wellbore pressure dynamically in well-killing

Casing pressure during well-killing is both an unknown variable that must be addressed and a time-dependent function. Therefore, the calculation of the dynamic reaction of wellbore pressure during well-killing is a dynamic indeterminate boundary problem. Due to the intricacy of the analytical solution technique, finding an analytical solution for the dynamic issue of uncertain boundaries is nearly impossible. Current numerical simulation software is only capable of resolving problems with defined bounds (such as flow or pressure) and is incapable of continuously calculating the wellbore pressure, which varies dynamically with well-killing time. Developing a dynamic reaction computation method for wellbore pressure during well-killing can solve this issue. Based on the mathematical model and definite solution conditions of the wellbore pressure dynamic response under well-killing conditions, this paper applies the finite difference principle and constructs the calculation method of choke and kill wellbore pressure dynamic response through reasonable mesh division of wellbore and gradual iteration of the calculation process. The resultsdemonstrate that the maximum wellhead casing pressure value and the time node of peak value are both highly congruent with the measured data, indicating the method’s high reliability and highlighting its significance for the progress of oil and gas well control safety.

Channel Prediction Using Ordinary Differential Equations for MIMO Systems

Channel state information (CSI) estimation is part of the most fundamental problems in 5G wireless communication systems. In mobile scenarios, outdated CSI will have a serious negative impact on various adaptive transmission systems, resulting in system performance degradation. To obtain accurate CSI, it is crucial to predict CSI at future moments. In this paper, we propose an efficient channel prediction method in multiple-input multiple-output (MIMO) systems, which combines genetic programming (GP) with higher-order differential equation (HODE) modeling for prediction, named GPODE. In the first place, the variation of one-dimensional data is depicted by using higher-order differential, and the higher-order differential data is modeled by GP to obtain an explicit model. Then, a definite order condition is given for the modeling of HODE, and an effective prediction interval is given. In order to accommodate to the rapidly changing channel, the proposed method is improved by taking the rough prediction results of Autoregression (AR) model as a priori, i.e., Im-GPODE channel prediction method. Given the effective interval, an online framework is proposed for the prediction. To verify the validity of the proposed methods, We use the data generated by the Cluster Delay Line (CDL) channel model for validation. The results show that the proposed methods has higher accuracy than other traditional prediction methods.

Decoding the role of immune T cells: A new territory for improvement of metabolic-associated fatty liver disease.

Metabolic-associated fatty liver disease (MAFLD) is a new emerging concept and is associated with metabolic dysfunction, generally replacing the name of nonalcoholic fatty liver disease (NAFLD) due to heterogeneous liver condition and inaccuracies in definition. The prevalence of MAFLD is rising by yeardue to dietary changes, metabolic disorders, and no approved therapy, affecting a quarter of the global population and representing amajor economic problem that burdens healthcare systems. Currently, in addition to the common causative factors like insulin resistance, oxidative stress, and lipotoxicity, the role of immune cells, especially T cells, played in MAFLD is increasingly being emphasized by global scholars. Based on the diverse classification and pathophysiological effects of immune T cells, we comprehensively analyzed their bidirectional regulatory effects on the hepatic inflammatory microenvironment and MAFLD progression. This interaction between MAFLD and T cells was also associated with hepatic-intestinal immune crosstalk and gut microbiota homeostasis. Moreover, we pointed out several T-cell-based therapeutic approaches including but not limited to adoptive transfer of T cells, fecal microbiota transplantation, and drug therapy, especially for natural products and Chinese herbal prescriptions. Overall, this study contributes to a better understanding of the important role of T cells played in MAFLD progression and corresponding therapeutic options and provides a potential reference for further drug development.