Linear Flow Research Articles

Möbius Disjointness for product flows of rigid dynamical systems and affine linear flows

Möbius Disjointness for product flows of rigid dynamical systems and affine linear flows

ВИЗНАЧЕННЯ КУСКОВО-ЛІНІЙНОГО ТРЕНДУ НЕСТАЦІОНАРНОГО ЧАСОВОГО РЯДУ НА ОСНОВІ ІНТЕЛЕКТУАЛЬНОГО АНАЛІЗУ ДАНИХ. II. МАШИННI ЕКСПЕРИМЕНТИ ТА РОЗВ’ЯЗАННЯ ПРАКТИЧНОЇ ЗАДАЧІ

The article describes the results of the approbation of the method of constructing a piecewise-linear trend, which can have breaks at the switching points as well as be continuous at these points, i.e., represent a linear flow. An example of applying the method for constructing a linear regression with switches, which has two independent variables with a trend, is considered. The problem of spline approximation of the time series of logarithms of the number of infected people with COVID-19 in Ukraine is stated and solved. Keywords: trend, regression, switch point, spline, real-time calculation.

ESTIMATING THE PHOTOSYSTEM’S EFFICIENCY, ANTIOXIDANTS ACTIVITY AND PLANT WATER RELATIONS OF TOMATO UNDER WATER DEFICIT CONDITIONS

Due to physiological repercussions, the tomato crop has decreased productivity caused by drought throughout its entire life cycle. The tomato harvest has exceeded expectations due to a worldwide water resource limitation. The objective of subjecting the tomato cultivars Flanto and Sahel, to a self-imposed drought was to investigate the interrelationships among biochemical, physiological, enzymatic, and water-related factors. Five varying levels of moisture strongly impacted all plant attributes: 100%, 80%, 60%, 40%, and 20% when subjected to drought stress. The lack of water resulted in notable improvements in some metrics. Some examples of these traits include linear electron flow (LEF), photosynthetic efficiency (PSE), inward light dissipation ratio (qP), catalase activity (CAT), ascorbate peroxidase activity (APX), and leaf water potential (LEWP). Consider, for example, the intriguing discoveries concerning photosystem II, non-photochemical quenching, chlorophyll levels, leaf osmotic potential, and leaf turgor potential.

Sistem Informasi Kelayakan Berlayar dan Kecelakaan Kapal Berbasis Website

Abstracts - Sea transportation does not only function to connect regions in Indonesia, in this case shipping is actually one of the main veins of the economy and its strategy is to connect the gaps between regions, in this case the software development approach used in making this website is a linear flow and sequential, involving needs analysis, design, implementation, testing, and maintenance. The background explanation above illustrates the need for rapid data collection regarding the seaworthiness of company ships and the causes of ship accidents and the losses they cause. To meet these needs, the idea of making a website-based application is proposed. The computer was chosen as a device that supports the application of the plan, so that the application can facilitate the exchange of information when a ship accident occurs. A linear and sequential software development approach is used, with sequential development phases, including requirements analysis, design, implementation, testing, and maintenance. Various tools, such as XAMPP, Sublime Text Editor 3, PHP, Bootstrap, and MySQL PHPMyadmin, were used in the creation of a seaworthiness information system and shipwreck data. Through this website, related parties, including the Directorate General of the Ministry of Sea Transportation and the National Transportation Safety Commission, can provide information to the public in an efficient and up-to-date manner regarding ship accident incidents.

SUPPLY FLOW OPTIMIZATION IN THE PROCESS OF ACQUISITION OF WORK UNIFORMS: A CASE STUDY IN A NETWORK OF DEPARTMENT STORES IN JOINVILLE

With the growing need to serve customers with greater quality, seeking competitive advantages, it is essential that service employees remain properly uniformed. For this need to be met, the company must deliver these uniforms, maintaining a coherent and well-defined process flow in the logistics of this material. This article aims to optimize the supply flow in the process of acquiring work uniforms in a chain of department stores in Joinville through lean thinking. To meet this objective, it was necessary to analyze the current process flow and apply purchasing management, inventory management and process management tools. These applications resulted in the elimination of waste, increased process quality and a linear flow, without bifurcations, looping’s and low complexity.

Effects of wheat protein on hot-extrusion 3D-printing performance and the release behaviours of caffeic acid-loaded wheat starch

In this study, the effects of wheat protein (WP) on the hot-extrusion 3D-printing (HE-3DP) performance of wheat starch (WS) gels, as well as effects of such gels on the encapsulation of caffeic acid, were investigated for the first time. The HE-3DP results show that the addition of WP can reduce print-line width and improve printing accuracy and fidelity, and the best printing results were achieved when using gels with 10 % WP. The rheological results show that WP reduced the gels' linear viscoelastic region (LVR), yield stress (τy), flow stress (τf) and consistency factor (K) but increased their structural recovery rate, which facilitated smooth extrusion during 3D printing and, thus, improved printing accuracy. The analysis of X-ray diffraction and small-angle X-ray scattering indicates that adding WP to WS could increase the mass fractal dimension and lead to denser gel network structures. The results regarding release kinetics demonstrate that the maximum release of caffeic acid from gels decreased by 28 % with the addition of WP, indicating slow-release behaviour. This study provided valuable information about processing wheat products via 3D printing.

Impact of Implementing Circular Waste Management System and Energy Recovery in a City with 100,000 Inhabitants on Nitrogen Emissions by 2035

Recent years have observed a reconstruction of the waste management system from a linear resource flow economy to a circular economy. This approach is reflected in the provisions of the Waste Framework Directive (2018), which introduces, among others, new recycling targets for municipal waste which require, by 2025, 55% of the municipal waste to be recycled, in 2030—60%, and in 2035—65%. The ambitious targets adopted for preparing for the reuse and recycling of municipal waste will not be achieved without a high level of the recycling of bio-waste. This paper studies the quantification of municipal waste and nitrogen in a circular municipal waste management system (MWM) implemented for a city of 100,000. It was assumed that MWM would meet the requirements in terms of EU and Polish circular waste management goal legislation for the years 2025, 2030 and 2035. The research results showed that the development of a separate waste collection will reduce the waste delivered to MBT. The required MBT capacity will decrease by almost 2.4 times. Moreover, it has been shown that the introduction of a closed-loop MWM will result in an almost two-fold reduction in the amount of nitrogen going to the landfill and an increase in the mass of nitrogen that can be used to fertilize the soil (by approximately 22%). Furthermore, it has been shown that the most favorable option for an organic waste treatment is the anaerobic–aerobic process. This solution provides the highest biogas production and the lowest nitrogen gas emissions to air.

Flutter and divergence zones of perovskite solar cell-based panels of aircraft wings in subsonic airflow

Solar-powered aircraft have advantages such as quite long flight time and resource conservation. In recent years, with the improvements in solar cell efficiency, lightweight structural design, microelectronics, and automation control technology, more and more countries and organizations have conducted research on solar-powered aircraft. Solar cells are an important component of solar-powered aircraft systems. Perovskite solar cells have the advantages of high flexibility, lightweight, and high specific power, making them the ideal material for solar-powered aircraft wings. To receive as much sunlight radiation as possible and improve the lift-to-drag ratio of the entire aircraft, solar-powered aircraft have a high aspect ratio, making them more sensitive to changes in airflow. Therefore, the stability zones and vibration of perovskite solar cell (PSC) panels in subsonic airflow were studied for the first time. Additionally, to enhance the novelty of the paper and present more comprehensive results, the effect of the nanomaterial properties of one-layered perovskite solar cell substrates reinforced by carbon nanotubes and graphene platelets on the flutter and divergence phenomenon was investigated. To accurately simulate the displacement field after the composite perovskite panel is bent, Reddy's high-order shear deformation theory was adopted. The PSC panel's aerodynamic-elastic coupling motion equations were established by combining Hamilton's principle with the linear potential flow theory and the Bernoulli equation. The dynamic equations were discretized using a meshless numerical method to obtain the generalized multi-parameter characteristic equations. The obtained natural frequencies and critical divergence speeds were compared with published literature to validate the correctness of the aerodynamic model and laminated board model. The divergence instability and flutter instability of the PSC nanocomposite panel were investigated for changing the thickness, nano-fillers, porosity, laying angle, and aspect ratio of the substrate. We showed, that the PSC panel has a divergence instability state first, and then flutter instability appears. Additionally, the substrate nanomaterial parameters of the PSC panel significantly affect shifting divergence and flutter zones. Interestingly, the corresponding natural frequency increases when flutter occurs with an increase in the porosity volume.

Electrocoagulation Technique for Treating Swine Slaughterhouse Wastewater from Batch to Semicontinuous Operation Mode

In this study, industrial swine slaughterhouse wastewater was treated by electrocoagulation process using batch and semicontinuous operation systems. Electrochemical technique was carried out in batch operation mode during 2.5 h applying different current densities in sulfate and chloride media. After finding the best operating parameters in batch mode (lab-scale), the process was transferred to a semicontinuous pre-pilot scale process using a filter-press FM01-LC type electrochemical reactor fitted with flat plate aluminum electrodes. In this stage, distinct current densities and mean linear flow rates were assessed.Total organic carbon, chemical oxygen demand, total phosphorus, total nitrogen, and potassium among other parameters were analyzed during both treatments. The industrial swine slaughterhouse wastewater contained TOC 333 mg L–1, COD 1765 mg L–1, TP 13.55 mg L–1, TN 327 mg L–1, K 45 mg L–1, turbidity 102 NTU, color –absorbance 0.90 A.U. at 415 nm–, conductivity 1.9 mS cm–1, and pH 6.9. The highest TOC removal efficiency (72.7%), in semicontinuous process, was found at j = 25 mA cm-2 and ur = 0.64 cm s-1 with an energy consumption of 19.80 kW h m-3. Residual COD and TP concentrations met the international standard limits. Moreover, complete discoloration and disinfection were achieved. EDXRF, SEM, EDAX, XRD, and FTIR analyzes indicate pollutants were removed by adsorption on aluminum/iron hydroxides/oxyhydroxides.

Piecewise Linear Power Flow Algorithm of DC Distribution Networks Considering Automatic Adjustment of VSC Control Strategy

Voltage source converter (VSC)-based DC distribution networks (DCDNs) can automatically adjust the control strategy of overloaded VSCs to adapt to the variation in renewable energy power, but it brings difficulties to the steady-state performance analysis of DCDNs. This paper presents a piecewise linear power flow (PLPF) algorithm to estimate the joint effect of power disturbance and VSC control strategy adjustment on steady-state performance. Firstly, according to the VSC power balance, the critical point of the VSC hitting the capacity limit is directly determined, and the power variations in each node before VSC control strategy adjustment are obtained. Then, the linear power flow is revised considering the VSC control strategy adjustment. Inversion of the block Jacobian matrix is used to improve the calculation speed of linear power flow revision. Finally, linear power flow calculation is performed in each stage, and the steady-state performance is obtained by using the superposition method. Simulation results show that the proposed PLPF model can estimate the steady-state performance faster and more simply.

A novel state estimation method for distribution networks with low observability based on linear AC optimal power flow model

The state estimation (SE) problem is one of the key functions in real-time control and management of modern electrical distribution networks. However, due to the complex network configuration and the limited number of measuring devices in these networks, the SE problem faces many challenges. In this manuscript, a new state estimation methodology is proposed based on the AC optimal power flow (ACOPF) model for distribution networks with a small number of real-time measurements. The proposed method is formulated in the form of a mixed integer linear programming problem (MILP), where the estimated states are regarded as the decision variables in the optimization problem. The load consumption values are also assumed as the decision variables where the estimation limits of these variables are determined by pseudo-measurements taken from the historical data. The main objective function is to maximize the state estimation accuracy, while the power flow equations are defined as the problem constraints. The efficiency of the proposed methodology is evaluated by implementing on the test networks and comparing the estimation results accuracy with the conventional weighted least squares (WLS) method. The obtained numerical results show the superior performance of OPF-based SE model to WLS method. Moreover, linearizing the formulation demonstrates an acceptable precision while ensuring convergence and optimum solution in low observability conditions.

Towards an optimal frequency and time response of singe-tube pressure measurement systems under continuum-flow conditions

The pressure transmission tube, as part of a pressure measurement system, generally has a considerable influence on its dynamic characteristics. The paper deals with the mathematical modelling of the dynamic behaviour of pressure transmission tubes with the aim of providing guidelines for the optimal design of such systems in the frequency and time domains. The mathematical models used are based on linear wave theory and continuum flow mechanics with no-slip and isothermal boundary conditions. The frequency responses were evaluated in terms of frequency bandwidth and the transient step responses in terms of settling and rise times. Following a systematic analysis of these characteristic parameters, we derived an analytically formulated optimisation objective function defining the transition between the low-wavenumber and high-wavenumber pressure waves in the pressure transmission tubes. The demanded dynamic behaviour in the frequency and time domains can be achieved through an appropriate ratio between the actual tube radius and the so-called transition tube radius, which was derived as a function of the tube length, end volume and fluid properties.

A linear Distflow model considering line shunts for fast calculation and voltage control of power distribution systems

The line shunts are usually ignored by various linear power flow (PF) models in power distribution system analysis, planning and optimization. However, “charging effects” from line shunts of underground/submarine power cables would cause non-negligible model errors for these commonly used PF models. In this paper, we propose a modified Linear Distflow model (LinDist) with line shunts, i.e., LinDistS. We also further propose its extensions considering the ZIP load, weakly-meshed topology and unbalanced three-phase systems. Moreover, the linearization error of voltage component is theoretically analyzed. Case studies show that compared with other models, the proposed LinDistS achieves the descent calculation accuracy and efficiency. We also show the application scope of LinDistS by a Volt/VAr control (VVC) framework with distributed generators, mainly photovoltaic (PV), and the non-negligible “charging effect”. Simulation exhibits that with LinDistS, the VVC can optimally dispatch the shunt capacitors and also optimize the real-time reactive power output of PV. Moreover, with LinDistS, the VVC shows better solutions’ consistency and higher computing efficiency compared to traditional VVC methods.

Linear hydrodynamic model of rotating lift-based wave energy converters

A linear potential flow model of a rotating lift-based wave energy converter is developed by assuming that the lift is generated by a pair of equal and opposite circulations and that the amplitude of motion is small. The linearisation of the hydrodynamics means that the forces can decomposed and expressions for the wave excitation force and radiation damping force are derived independently and shown to be related to each other through the Haskind Relations. The expressions for the forces are used to show that there is an optimum phase and product of circulation and radius of rotation to maximise the wave power extracted, which is equivalent to the optimum phase and amplitude of motion from ‘conventional’ wave energy converter theory. It is also shown that at this optimum condition 100% of the incident wave energy can be extracted. It is shown that the forces are directly proportional to the velocities due to the motion of the vortices, the water particle velocities due to the incident wave, and the water particle velocities induced by the vortices. The effect of the vortex-induced water particle velocities is considered and the importance of including these velocities on the passive generation of circulation, e.g. by hydrofoils, is highlighted. The impact of a sub-optimum product of circulation and radius of rotation is also investigated and shown that the power capture is not highly sensitive to the optimal conditions in the same way as ‘conventional’ wave energy converters

Einstein material balance and modeling of the flow of compressible fluid near the boundary

We consider sewing machinery between nite difference and analytical solutions de ned at different scales: far away and near the source of the perturbation of the flow. One of the essences of the approach is that the coarse problem and the boundary-value problem in the proxy of the source model two different flows. In his remarkable paper, Peaceman proposes a framework for dealing with solutions de ned on different scales for linear time independent problems by introducing the famous Peaceman well block radius. In this article, we consider a novel problem: how to solve this issue for transient flow generated by the compressibility of the fluid. We are proposing a method to glue solution via total fluxes, which are prede ned on coarse grid, and changes in pressure, due to compressibility, in the block containing production (injection) well. It is important to mention that the coarse solution “does not see” the boundary. From an industrial point of view, our report provides a mathematical tool for the analytical interpretation of simulated data for compressible fluid flow around a well in a porous medium. It can be considered a mathematical “shirt” on the Peaceman well-block radius formula for linear (Darcy) transient flow but can be applied in much more general scenarios. In the article, we use the Einstein approach to derive the material balance equation, a key instrument to de ne R0. We will expand the Einstein approach for three regimes of Darcy and non-Darcy flows for compressible fluids (time-dependent): 1. stationary; 2. pseudostationary; 3. boundary dominated. Note that in all known authors literature, the rate of production on the well is time-independent.

The State of Hemodynamics of Retinal Vessels in Primary Open-angle Glaucoma in Patients With Type 2 Diabetes Mellitus

Objective: to study the features of linear blood flow rate with central artery and retinal vein calibration in patients with POGC and type 2 diabetes. Examined 220 eyes (110 patients) with type 2 diabetes and 40 eyes (20 patients) with PAH without diabetes. The average age — 58 years old — 0,35. In addition to the common methods of research were: ophthalmoscopy with Goldman lens, binocular ophthalmoscope (Schepevsa), and lens Volk-90,0D (USA), gonioscopy with lenses (Krasnova, Goldman), tonometry by Maccov, NIidek (Japan) pneumototometry NT-2000, simplified tonography for Nesterov, OCT optical nerve disc and yellow spot Carl Zeiss Cirrus, HD OCT Model 4000/5000 Germany), OCT retinal vessels with calibre meter (Cirrus HD-Octiss Ultrasonic), Carl Ultrasonic (ISS) Central artery vessels and retinal veins (UZ — expert class system Sono Scapesq), ultrasound of the eyes. The data are processed statistically. In patients with PSA with SD 2 type of LSC reduction in the CAC at the initial and advanced stages up to 12.5 0.66 cm/s and 11 0.46 cm/s, with blood flow slowing in the CNS-LCC vessels 8.0.5 cm/s and 9.0 0.52 cm/s. In addition, the vascular calibre of the CAC increased to 91.5 0.67 μm and 93.5 0.65 μm at the initial and advanced stages of glaucoma, and the vascular size of the CAC was reduced to -97.6 0.19 μm at 75% and 93.5 0.9 μm at 50%, respectively, and expanded to 141.5 0.7%,7%. Revealed microcirculatory disorders in retinal vessels at POGC with type 2 diabetes allow recommending patients to conduct adequate therapy.

Unraveling the functioning of the vadose zone in alpine karst aquifers: New insights from a tracer test in the Migovec cave system (Julian alps, NW Slovenia)

The aquifers of alpine karst and high karst plateaus are abundant water resources. They are difficult to characterise due to their complex, partly glaciokarstic, evolution in active tectonic environments, and an unsaturated zone up to two kilometres thick. We present and discuss the results of a tracing test in the alpine karst of the Julian Alps (Slovenia), more precisely in the Migovec System, the longest cave system in Slovenia (length = 43 km, depth = 972 m). The cave extends below a mountain ridge that separates the Soča and Sava Valleys, thus forming a topographic divide between the Adriatic and Black Sea basins, which gives the test greater regional significance. In early September 2019, three kilograms of uranine were injected into a perched lake in a remote part of the system, approximately 900 metres below the plateau and 100 metres above the low water table. All known springs in the valleys on either side of the mountain were monitored by manual or instrumental sampling and a field fluorometer. Due to the unexpectedly dry season, no tracer was detected at any site for two months until a heavy rainfall event in early November. Subsequently, about 60-65 % of the tracer mass appeared within 60 hours in the Tolminka River. No tracer was detected at other sites, either becauseit was not present or because it was highly diluted. The study suggests that the lake containing the tracer is bypassed by the vadose flow and that the tracer was only mobilised during large events when the lake became part of the epihreatic flow. The linear peak flow velocity from the injection site to the Tolminka Spring was only about 1.7 m/h. However, assuming that the tracer was only mobilised by the large rain event, the velocity would be 70 m/h. The study highlights the challenges and pitfalls of water tracing in alpine karst systems and suggests ways to avoid them.

Efficient contingency analysis of power systems using linear power flow with generalized warm-start compensation

Contingency analysis (CA) is fundamental to power system planning and operation. The compensation method and linear power flow (LPF) models are frequently used in CA to boost efficiency. However, the conventional compensation scheme fails to adapt to modern LPF models with novel structures. To bridge this gap, this paper proposes a generalized warm-start compensation algorithm (GWSCA) for LPFs. To efficiently calculate the inversion of a perturbed coefficient matrix in LPF models, a generalized decomposition method is devised based on the matrix inverse lemma and full rank decomposition. A warm-start strategy is developed to improve the computational accuracy by using the precontingency operating point of a power grid. The proposed GWSCA is incorporated with an LPF model based on logarithmic transformation of voltage magnitudes to implement fast and accurate CA. Simulation results show that GWSCA outperforms the conventional algorithms in terms of computational efficiency and accuracy.

Utilizing Craft Techniques in Zero Waste Fashion Design Clothing

The role of research in design is to develop the potential that drives the creation of novel value in design. In the research process for design, the majority of designer-students have difficulties in determining the starting point or initial idea of a design, so they have the potential not to have a train of thought regarding what needs to be done in realizing the design and do not know the next process. One aspect that can enrich design ideas and novelty in fashion products is the application of craft techniques. With the application of craft techniques, the data and facts obtained become increasingly massive. So that the series of ideas-research-design requires a clear mapping of the flow of thinking in the creative process. Today's student-designers cannot be limited to just one research method, knowing that conceptual ideas can start from anywhere, such as design concept ideas that start from craft techniques in a linear mapping flow. This can be a reference regarding the linear flow of ideas-research-design that is carried out in zero waste fashion design to find out its potential, especially in the application of craft techniques. This research was conducted qualitatively by reviewing literature data and looking at examples of case studies from the student-designer work process using the linear method. Observations are made periodically for students who have designed the application of craft techniques to zero waste fashion design, to become research subjects and find out their creative process. The result of this study is an analysis of fashion product design methods with the application of craft techniques that have been carried out in a linear way of thinking as a reference for designers in producing innovative works.

Coupling analysis of liquid sloshing and box sway motion under irregular wave actions

The coupling effect between the internal fluid sloshing and the box sway motion under irregular wave action is studied in this work. For describing external wave and internal sloshing actions, a hybrid numerical method combining linear potential flow and viscous flow is adopted. Numerical simulations show that coupling sloshing action plays an important role around sloshing natural frequencies. The significant resistant and enhanced actions can be observed at the frequencies around sloshing natural frequencies in regular waves. However, the above coupling effect approaches weak under irregular wave actions. The phase relation between the internal sloshing forces and external wave forces in regular waves cannot be found under irregular wave actions, which is the main reason for the decreased coupling sloshing effect. In all, the sway motion responses between irregular and regular wave actions show evident different behaviors from each other.