Static State Research Articles

Intraprocedural computed tomography-guided navigation with ventilatory strategy for atelectasis (ICNVA): a modified electromagnetic navigation bronchoscopy.

Computed tomography (CT)-body divergence limits the accuracy of electromagnetic navigation bronchoscopy (ENB) in peripheral lung lesions diagnosis. We developed intraprocedural CT-guided navigation with ventilatory strategy for atelectasis (ICNVA) ENB for patients with peripheral lung lesions. Retrospective observational study in which ten consecutive patients with pulmonary lesions (without bronchial direct connection) underwent ICNVA-ENB was conducted. During ICNVA-ENB, intraoperative CT data were used for ENB path planning, and a new ventilation strategy were employed to help maintain the pulmonary region in a static and inflation state which reduce CT to body divergence. We collected three sets of CT data: preENB CT, post-anesthesia intubation CT, and postENB CT. To evaluate the accuracy of ICNVA-ENB, we measured the distance between the ENB probe and the actual lesion location, but also recorded the results of rapid on-site evaluation (ROSE), and postoperative pathology. To evaluate the impact of CT-body divergence induced by atelectasis, we calculated the mutual position distance of target lesions in preENB CT, post-anesthesia intubation CT and postENB CT. Furthermore, ENB operation time and operative complications were recorded. Our analysis revealed that the distance between the navigation probe with the actual location of lesion center was 4-10 (5.90±1.73) mm. The ROSE results were consistent with the postoperative pathological diagnosis in 9 out of 10 patients (90%). The ICNVA-ENB atelectasis CT-body divergence was smaller than traditional ENB (12.10±3.67 vs. 6.60±2.59 mm, P<0.01). The ENB operation time was 20-53 (29.30±10.14) minutes and one patient developed slight intrapulmonary hemorrhage. ICNVA-ENB can reduce the CT-body divergence and appears to be safe and accurate for patients with peripheral lung lesions.

Geotechnical justification of the stadium construction on water-saturated soils under seismic loading

One of the main issues in the design of bases and foundations on water-saturated soils in conditions of possible seismic impacts is the geotechnical substantiation of the possibil-ity of construction. Among the main influencing factors, one can single out the assessment of the ability of water-saturated sandy soil to resist vibration liquefaction. The paper presents the re-sults of studying the behavior of sandy soil samples under conditions of triaxial cyclic loading, which is equivalent in strength to seismic action. The urgency of the problem lies in the study of the process of vibration liquefaction with an assessment of the deformability of water-saturated soils under dynamic influences. The tests were carried out in a pneumatic stabilometer. A special technique has been developed that provides for the imposition of dynamic stresses on the static stress state of the samples. The criteria for vibration liquefaction have been determined. A ge-otechnical substantiation of the possibility of building a stadium on water-saturated sandy soils under conditions of seismic loading has been carried out. The parameters of the earthquake, in which the soils will show liquefaction, have been established.

A Contrastive Study of Static and Dynamic State of Expressing in English and Chinese Language Landscapes

A Contrastive Study of Static and Dynamic State of Expressing in English and Chinese Language Landscapes

Assessment on power systems non-deterministic state estimation algorithms

Power systems are operated in a deterministic way. However, the increase in uncertainties (caused by measurement and communication errors or the absence of complete knowledge of the measured quantity) requires algorithms capable of assessing randomness in real-time monitoring and operation of energy management systems. Among them, state estimation is a fundamental element that provides complete and reliable information about the current network state. This paper offers a review of non-deterministic algorithms, used to assess the randomness caused by the uncertainties in power system state estimation. Depending on the uncertainty modeling method, different static and dynamic non-deterministic state estimation algorithms for transmission and distribution systems are reviewed. Also, four of the most relevant algorithms are implemented and results are compared for distribution networks. The relevance of such models, as well as their motivation, are addressed. • This paper offers a review of methods employed for power system uncertainty modeling. • Review of state estimation algorithms based on uncertainty modeling methods. • Non-deterministic state estimation algorithms in transmission and distribution grids. • Non-deterministic state estimators in low voltage networks have been implemented. • Future research lines on non-deterministic state estimation are proposed.

Interpreting ultrasonic pulse velocities and elastic properties of lac du bonnet granite under compression

The measurement of ultrasonic velocities in rock core is a straightforward, non-destructive, economic method to estimate rock material properties conducted by emitting high frequency acoustic waves through the rock core. The velocities of compressional and shear waves (P- and S-waves, respectively) are influenced by the unique microstructural characteristics of the rock. Once wave velocities and bulk density for each sample have been determined, the dynamic elastic material constants such as Young’s modulus, Poisson’s ratio, and shear modulus can be calculated. In theory, it is expected that the dynamic properties would be similar to the static properties calculated in uniaxial compression strength (UCS) tests. In UCS tests, elastic parameters are estimated using stress-strain relationships at approximately 50% of the peak strength. However, dynamic properties from the UPV method often do not match static properties. In this study, dynamic testing of the rock core is completed under two broad stress conditions: no compression and axial compression (UCS). This allows for a direct comparison between dynamic UPV testing data, and static data, and should produce a closer match between the dynamic and static testing data when dynamic UPV testing is conducted under stress conditions similar to the static testing stress state.

Detection of False Data Injection Attacks in Smart Grid Based on Joint Dynamic and Static State Estimation

Power system state estimation is an essential component of the modern power system energy management system (EMS), and accurate state estimation is an indispensable basis for subsequent work. However, the attacker can inject biases into measurements to launch false data injection attacks (FDIAs) in smart grids, which ultimately cause state estimates to deviate from security values. This paper proposed the joint use of static state estimation and dynamic state estimation to detect the FDIA, i.e. the joint use of weighted least squares (WLS) and extended Kalman filter (EKF) with exponential weighting function (WEKF), which improves the robustness of state estimation. Since the WLS estimation considers only the measurements at the current moment, the recursive feature of the WEKF enables the estimation process to involve both historical state and current measurements. Therefore, consistency tests and residual tests were performed using the estimations of WLS and WEKF to effectively detect FDIA. In addition, a cluster partitioning approach with approximate equal redundancy of subsystems is proposed to locate the FDIA. The detection of FDIA triggers the partitioning of the network system, and then the chi-square test is used separately in each sub-network to determine the location of FDIA. Finally, the experimental results in the IEEE-14 bus system and the IEEE-30 bus system demonstrate that the approach can effectively detect and locate FDIAs.

Three Dimensional Coupling between Elastic and Thermal Fields in the Static Analysis of Multilayered Composite Shells

This new work aims to develop a full coupled thermomechanical method including both the temperature profile and displacements as primary unknowns of the model. This generic full coupled 3D exact shell model permits the thermal stress investigation of laminated isotropic, composite and sandwich structures. Cylindrical and spherical panels, cylinders and plates are analyzed in orthogonal mixed curved reference coordinates. The 3D equilibrium relations and the 3D Fourier heat conduction equation for spherical shells are coupled and they trivially can be simplified in those for plates and cylindrical panels. The exponential matrix methodology is used to find the solutions of a full coupled model based on coupled differential relations with respect to the thickness coordinate. The analytical solution is based on theories of simply supported edges and harmonic relations for displacement components and sovra-temperature. The sovra-temperature magnitudes are directly applied at the outer faces through static state hypotheses. As a consequence, the sovra-temperature description is assumed to be an unknown variable of the model and it is calculated in the same way as the three displacements. The final system is based on a set of coupled homogeneous differential relations of second order in the thickness coordinate. This system is reduced in a first order differential relation system by redoubling the number of unknowns. Therefore, the exponential matrix methodology is applied to calculate the solution. The temperature field effects are evaluated in the static investigation of shells and plates in terms of displacement and stress components. After an appropriate preliminary validation, new benchmarks are discussed for several thickness ratios, geometrical data, lamination sequences, materials and sovra-temperature values imposed at the outer faces. Results make evident the accordance between the uncoupled thermo-mechanical model and this new full coupled thermo-mechanical model without the need to separately solve the Fourier heat conduction relation. Both effects connected with the thickness layer and the related embedded materials are included in the conducted thermal stress analysis.

Robust Optimal Output-Tracking Control of Constrained Mechanical Systems With Application to Autonomous Rovers

This article presents a robust optimal output-tracking control strategy for underactuated mechanical systems whose motion is restricted by mixed holonomic and nonholonomic constraints. Autonomous rovers/cars and unmanned underwater/aerial vehicles are a few examples of such systems that must often operate in harsh environments and under uncertain conditions. We present a comprehensive control analysis of this large class of nonlinear systems, including the existing studies on local reachability and static state feedback linearization. We also propose a local observability analysis of the feedback transformed input–output linearized systems. Based on the input–output linearization of the holonomically restricted nominal system, we develop a sliding mode control strategy that is robust against the projected effects of uncertainties and disturbances on the system’s output. Asymptotic stability of the output toward a bounded desired trajectory is proven using Lyapunov’s direct method, while the system’s internal stability (in the sense of boundedness) is investigated based on the notion of tracking-error zero dynamics. Time-dependent bounded matched uncertainties in the inertia parameters and disturbance forces arising in the unrestricted system are considered in this study. We propose an optimal sliding manifold according to the finite-horizon linear-quadratic regulator design problem with split boundary value conditions. The developed control strategy is implemented on a six-wheel autonomous Lunar rover in a simulation environment and its performance is compared with that of an optimal proportional–integral–derivative feedback, feedforward controller. The optimal sliding mode controller shows superior performance in trajectory tracking with acceptable control actions.

Advances in Algorithms for Power System Static State Estimators: An Improved Solution for Bad Data Management and State Estimator Convergence

More than 50 years have passed since the first state estimator was introduced to power system operations, by Fred Schweppe, in 1969. Today, state estimation is the most important function in the energy management system (EMS) because the solution of the state estimator is the basis of other functions, including contingency analysis, security assessment, dynamitic security analysis, optimal power flow, and so on. Numerous research papers and reports have been published about trying to improve the performance of the power system state estimator since 1969. After the efforts of several decades by researchers and power engineers, today’s state estimator can be found in almost every power system control center worldwide. Power system state estimation was considered a mature area until the occurrence of a 14 August 2003 blackout in the northeastern United States. The state estimator at the control center crashed due to a single topology error in the system model, and the system operator could not take appropriate actions to avoid the occurrence of the blackout.

A Comparison Study of Dynamic State of English and Static State of Chinese and their Conversion in Translation

A Comparison Study of Dynamic State of English and Static State of Chinese and their Conversion in Translation

ЛИРИЧЕСКАЯ СИТУАЦИЯ В ЛИРИЧЕСКОМ СЮЖЕТЕ

The article aims mostly to define terminologically the lyrical situation as one of the main components of the lyrical plot. To achieve the intent, the article addresses the following objectives. First, analyzing the earlier writings on the subject, from “Aesthetics” by Hegel to modern works on the plotology and poetics of lyricism (B.V. Tomashevsky, V.M. Zhirmunsky, L.Ya. Ginzburg, T.I. Silman, Yu. Lotman, V. Grechnev, V.I. Tiupa, N.D. Tamarchenko and others). Secondly, formulating our own definition of the lyrical situation as a static state of the inner world of a lyric verse. Third, showing the relationship of the situation with other important components of the lyrical plot. It is a spatiotemporal structure, which largely determines the lyrical situation, as well as the category of event, which is connected (or opposed) to the situation on the principle of dynamics / statics. Fourth, proving the correlation between the lyrical situation and the title of the poem. Finally, conclusions are drawn about the place of the lyrical situation in the lyrical plot of the poem, understood as a system of event-situational elements of the lyrical work, given from the position of the lyrical subject in the process of his reflection deployment.

Input-output Feedback Linearization Control for SM-PMSM

This paper introduces a velocity control strategy for Surface-Mounted Permanent Magnet Synchronous Motors SM-PMSM using exact linearization and input-output decoupling techniques, which are rooted in the principles of differential geometry. The primary aim of this control approach is to establish a static state feedback mechanism and to convert the nonlinear PMSM model into a linear, decoupled, and controllable system. Initially, the state model that represents the PMSM dynamics within the d-q reference frame is defined. Subsequently, the process of designing the control through linearization and input-output decoupling is outlined. Lastly, the synthesis of the compensator is grounded in the pole placement method, aiming to drive the direct current towards zero and ensure optimal torque operation. Simulation outcomes conducted on Matlab/Simulink demonstrate the efficacy of the speed control strategy, which is facilitated by a straightforward algorithm for practical implementation. However, it is inadequate against variations in machine parameters and load torque disturbances.

ACCESS TO THE RURAL ELECTRIFICATION INITIATIVE AND LIVELIHOOD IMPROVEMENT IN RURAL SANGA SUB COUNTY AND SANGA TOWN COUNCIL, UGANDA

Electricity is such an important utility that has transformed communities by empowering them financially through different activities that generate income (World Bank, 2015). Without electricity, many communities struggle to obtain the resources necessary to lift themselves out of a static state which greatly impacts people’s lives. Rural communities have a genuine and justifiable need for electricity (World Bank, 2016). These communities want to use electricity in relatively small quantities in order to: pump water, transport commodities, engage in income generating activities, practice modernized healthcare, and increase available light to extend work and leisure hours. Unfortunately, the road to achieving electrification is complex and costly. Currently, Uganda’s electricity sector is in flux: after the passage of the 1999 Electricity Act private enterprise was introduced into all aspects of the sector. Since that time, problems with power theft, insufficient supply, geographic isolation, and high infrastructure costs have inhibited rural communities from gaining access to electricity (RESP, 2013). This paper attempts to uncover some of the major challenges of making electricity accessible in Uganda, a developing country with a large rural population. Information was obtained through site visits, area appraisals, interviews with key informants, and general observation. The subsequent sections provide a reasonably extensive overview of the electricity sector in Uganda; foundational information that is necessary if one is to truly understand the electricity situation. Two case studies were covered in this study and these were; Rural Sanga Sub County and Sanga Town Council with their challenges as far as electrification is concerned. The final section contains recommendations for making electricity more accessible to rural Ugandans, based on the information gathered during the research period.

DEFORMED STATE’S SIMULATION OF THE FIRST-GRADE TITANIUM FOIL OF THE ACCELERATOR OUTPUT WINDOW

The output accelerator windows, particularly the used metal foils are studied. The work was carried out to assess the strength of the first-strength grade titanium foil and the choice of variable parameters of the thickness of the foil. Depending on the latter, the simulation was performed by the finite element analysis in the ABAQUS automated software environment. The distributions of displacements, plastic strains of concavity caused by pressure differences, and radial and circumferential stresses have been studied in the foil's static state for 10 metal foils with a thickness of 50…500 microns. The basic dimensions of the titanium metal film are introduced: thickness and diameter. Atmospheric pressure was applied as an external force of influence, and the vacuum pressure was assumed to be zero. The metal shells were divided into a large number of nodes, which ensured higher accuracy for simulations. As a result of simulation, curves of the displacements of the selected points of the metal foil in the direction of the Y axis, depending on the values of the radiuses, and the curves of the strains intensities distributions of the metal foil were built, which were also analyzed. The metal foil of the output window was investigated so that simulation results could be applied to both output windows: mechanical connection and diffusion connection.

Analysis of Targeted Coordinated Attacks on Decomposition-Based Robust State Estimation

The impact of false data injection (FDI) attacks on static state estimation of power systems has been actively studied in the past decade. In this paper, we consider an estimation method that first decomposes the system into islands and then implements robust regression estimators at the island level as well as the system level. We carry out an analysis to establish its advantages in terms of state estimation accuracy and attack detections. In particular, we focus on highly adversarial cases where the attacker can attack both the measurement vector and the regressor matrix and attempts to manipulate the states to targeted values. Our estimation approach employs a system decomposition method capable to generate islands small in their sizes and applies the robust estimation method of least trimmed squares. We make comparisons with methods using other decompositions and other robust estimators. To this end, we analyze the structure of the system topology and measurements and perform extensive simulations using the IEEE 14- and 118-bus systems. Furthermore, we investigate robustness improvement when phasor measurement units (PMUs) are available and hybrid state estimation can be employed.

Effect of MWCNTs nano-additive on a dual-fuel engine characteristics utilizing dairy scum oil methyl ester and producer gas

Alternative fuels are renewable sustainable and address socio-economic and environmental concerns. In this circumstance, this work is conducted in two stages. The first stage of the work involves, the preparation of nanoparticle (NP) blended fuels by adding 20, 40 and 60 ppm of multi-walled carbon nanotube (MWCNT) particles in dairy scum oil methyl ester (DiSOME) biodiesel using a mechanical homogenizer and ultrasonicator. Then, the steadiness characteristics of nanoparticle–mixed biodiesel fuels were studied under static state. In the next stage of the work, the effect of nanofluids on the attributes of combustion and emissions of aengine with 1-cylinder 4-stroke DI-direct injection),CI-compression ignition)which is run on DF-dual-fuel mode using DiSOME and PG-producer gas, has been examined. Investigation results indicated that at 80% load, DiSOME-PG combustion with 40 ppm of MWCNT nanoparticles provided 5.7% increased BTE, 23.5% decreased smoke opacity, 21.8% decreased HC, 22.4% decreased CO and 20.1% amplified NOx emissions related to the same fuel mixer but not with NPs. Adding NPs increased HRR - heat release rate and CP - cylinder pressure.

Role of Environmental Dynamic Polarizability in Static Excited State Properties of Embedded Molecular Systems: Application to Disordered Fluorographene Systems

We present an extension of the standard polarizable quantum mechanic/molecular mechanics (QM/MM) approach for treating environmental effects on excited state properties of embedded systems. A quantum polarizable atom model is derived from a full quantum description of the environment using perturbation theory for the system-environment coupling. Our model provides a more general description of the environment, including frequency-dependent atomic polarizabilities, without the loss of computational simplicity of the QM/MM approach. The classical polarizable atom description, used in the polarizable QM/MM approach, can be obtained as a limiting case of the present model. This result enables us to pinpoint approximations and assumptions about the system inherent to a classical polarizable atom description of the environment. We apply our method to fluorographene (FG)-based systems to investigate the effects of the FG sheet on excited state properties of impurities on the FG surface. The comparison to full quantum chemistry calculations and to the standard polarizable QM/MM approach on disordered fluorographene clusters reveals the importance of the frequency dependence of atomic polarizabilities for a proper treatment of the effects of the environment on both the transition energy shifts and the interaction energies.

Jamming Transitions in Astrocytes and Glioblastoma Are Induced by Cell Density and Tension

Collective behavior of cells emerges from coordination of cell-cell-interactions and is important to wound healing, embryonic and tumor development. Depending on cell density and cell-cell interactions, a transition from a migratory, fluid-like unjammed state to a more static and solid-like jammed state or vice versa can occur. Here, we analyze collective migration dynamics of astrocytes and glioblastoma cells using live cell imaging. Furthermore, atomic force microscopy, traction force microscopy and spheroid generation assays were used to study cell adhesion, traction and mechanics. Perturbations of traction and adhesion were induced via ROCK or myosin II inhibition. Whereas astrocytes resided within a non-migratory, jammed state, glioblastoma were migratory and unjammed. Furthermore, we demonstrated that a switch from an unjammed to a jammed state was induced upon alteration of the equilibrium between cell-cell-adhesion and tension from adhesion to tension dominated, via inhibition of ROCK or myosin II. Such behavior has implications for understanding the infiltration of the brain by glioblastoma cells and may help to identify new strategies to develop anti-migratory drugs and strategies for glioblastoma-treatment.

Medial meniscus posterior root tears and partial meniscectomy significantly increase stress in the knee joint during dynamic gait.

As a simple and invasive treatment, arthroscopic medial meniscal posterior horn resections (MMPHRs) can relieve the obstructive symptoms of medial meniscus posterior root tears (MMPRTs) but with the risk of aggravating biomechanical changes of the joint. The aim of this study was to analyze dynamic simulation of the knee joint after medial meniscus posterior root tear and posterior horn resection. This study established static and dynamic models of MMPRTs and MMPHRs on the basis of the intact medial meniscus model (IMM). In the finite element analysis, the three models were subjected to 1000N axial static load and the human walking gait load defined by the ISO14243-1 standard to evaluate the influence of MMPRTs and MMPHRs on knee joint mechanics during static standing and dynamic walking. In the static state, the load ratio of the medial and lateral compartments remained nearly constant (2:1), while in the dynamic state, the load ratio varied with the gait cycle. After MMPHRs, at 30% of the gait cycle, compared with the MMPRTs condition, the maximum von Mises stress of the lateral meniscus (LM) and the lateral tibial cartilage (LTC) were increased by 166.0% and 50.0%, respectively, while they changed by less than 5% during static analysis. The maximum von Mises stress of the medial meniscus (MM) decreased by 55.7%, and that of the medial femoral cartilage (MFC) increased by 53.5%. After MMPHRs, compared with MMPRTs, there was no significant stress increase in articular cartilage in static analysis, but there was a stress increase and concentration in both medial and lateral compartments in dynamic analysis, which may aggravate joint degeneration. Therefore, in clinical treatments, restoring the natural structure of MMPRTs is first recommended, especially for physically active patients.

Empirical Validation of Free Vibration of Sagging Cables

Sagging cables lack unique natural state, but possess unique equilibrium state under sustained loads. However, for the purpose of predicting their dynamic response, the static equilibrium state of heavy cables under self-weight is assumed to be their initial state. The theory of sagging elastic cables presented earlier by the Authors pertains to weightless cables carrying nodal masses apart from static and inertial forces. For applying the proposed theory for sagging heavy cables, the cable is divided into ten segments of equal length. The initial equilibrium configuration of the cable fixed at both the ends is determined by the weights of these lumped nodal masses applied at ten nodes with one end fixed. The stiffness matrix of the cable is determined from tangent configurational flexibility matrix and tangent elastic flexibility matrix of twenty degree of freedom system. The cable tied at both the ends in an equilibrium state is set into motion by releasing it at one end. The theoretically predicted response of the cable is compared with the experimental data from the two investigations. The first experimental investigation by Fried pertains to the planar undamped vibrations of a sagging elastic cable, in which cable is released from its right end and its configurations are plotted at regular time intervals of 0.001s. In the second investigation by Koh, Zhang and Quek, the configurations of a different cable at regular time intervals of 0.125s during half the vibration cycle is measured. The dynamic tensile force at the fixed end has also been predicted in the latter case. The theoretical prediction of the evolving cable configuration have been found to be compatible with experimental data.