Passive Load Research Articles

Harnessing Natural Pollen as Sustained-Release, Mucoadhesive, and Biosafe Drug Microcapsules for Intravesical Instillation in Bladder Cancer Treatment.

Intravesical instillation is essential for bladder cancer treatment, but current therapy suffers from brief drug retention and insufficient contact bladder contact. Nano- and micro-sized capsules-based drug delivery systems are expected to solve these problems, which, however, face challenges such as weak mucoadhesion, low biosafety, and processing complexity, limiting their scalable application. In this study, the power of plant pollen-derived microcapsules, sporopollenin exine capsules (SECs) is harnessed that are produced by sequentially defatting and acidolysis sunflower pollen, to passive load with pirarubicin and achieve biosafe and high-efficiency intravesical chemotherapy. SECs exhibit no significant toxic effects in vitro or in vivo. Taking advantage of its intrinsic microscale core-shell structure and spiny surface topography, convenient encapsulation is achieved with an efficiency of 45.3±1.43% and sustained release of the simulate drug, and strong adhesion to the bladder mucosa even after multiple urination, which reduces the instillation-maintenance time to just 20 min. Drugs encapsulated in SECs maintained higher concentrations in the bladder for up to 5 h compared to those without SECs. In a murine orthotopic bladder cancer model, SECs enhance the intravesical chemotherapy effect of pirorubicin (increased by 38%). The study introduces an innovative, naturally occurring drug carrier for advancing future intravesical instillation therapies.

A Novel Approach to Transient Fourier Analysis for Electrical Engineering Applications

This paper presents a detailed investigation into the application of transient Fourier analysis in select electrical engineering contexts. Two novel approaches for addressing transient analysis are introduced. The first approach combines the Fourier series with the Laplace–Carson (L-C) transform in the complex domain, utilizing complex time vectors to streamline the computation of the original function. The inverse transformation back into the time domain is achieved using the Cauchy-Heaviside (C-H) method. The second approach applies the Fourier transform (F-Τ) for the transient analysis of a power converter circuit with both passive and active loads. The method of complex conjugate amplitudes is employed for steady-state analysis. Both contributions represent innovative approaches within this study. The process begins with Fourier series expansions and the computation of Fourier coefficients, followed by solving the system’s steady-state and transient responses. The transient states are then confirmed using the Fourier transform. To validate these findings, the analytical results are verified through simulations conducted in the Matlab/Simulink R2023b environment.

A new calculation method for the response of active-passive bridge piles considering pile-soil interface friction

The pile foundation of bridges under unregulated surcharge loads experiences a complex force pattern, which is subject to active loads and passive loads. In this paper, a more comprehensive calculation method for the response of active-passive piles was proposed, which considered the effect of pile-soil interface friction and soil stress states on the passive loads. First, the Ito theory was improved by adopting the adhesion c a and external friction angle φ a to characterize the pile-soil interface friction. Then, the soil around the pile in elastic, elastoplastic, and plastic flow states was considered to calculate the variation of the passive load. Finally, a nonlinear p-y curve was introduced to establish the calculation model of active-passive piles, and the finite difference program CPAPP was prepared for the solution. The results show that the pile response calculated by CPAPP is consistent with the field measurement, indicating that the proposed calculation method has high accuracy. When the soil is in an elastic state, the pile-soil interface friction does not affect the passive load. When the soil is in a plastic state, the passive load is closely related to soil strength parameters and pile-soil interface friction parameters.

Improved Interfacial Electron Dynamics with Block Poly(4-vinylpyridine)-Poly(styrene) Polymers for Efficient and Long-Lasting Dye-Sensitized Solar Cells.

Dye-sensitized solar cells (DSSCs) have recently entered the market for indoor photovoltaics. Fast electron injection from dye to titania, the lifetime of the excited dye, and the suppression of back electron recombination at the photoanode/electrolyte interface are crucial for a high photocurrent conversion efficiency (PCE). This study presents block copolymers of poly(4-vinylpyridine) and poly(styrene)-P4VP67-b-PSt x(x=23;61) as efficient accelerators of electron injection from dye to titania with extended lifetime excited states and long-lasting back electron recombination suppression. P4VP67-b-PSt23 and P4VP67-b-PSt61 rendered devices with PCEs of 10.0 and 9.8%, respectively, under AM 1.5G light; PCEs of 19.4 and 16.4% under 1000 lx LED light were attained. Copolymers provided a stable PCE with the two most popular I3 -/3I- electrolytes based on ACN and 3-methoxypropionitrile solvents; PCE history was tracked in the dark and under 1000 h of continuous light soaking with passive load according to ISOS-D1 and ISOS-L2 aging protocols, respectively. The impact of the polymer molecular structure on electron recombination, charge injection, dye anchoring, light absorption, photocurrent generation, and PCE and the long-term history of photovoltaic metrics are discussed.

The consequence of ignoring load modeling on the circuit breaker selection in densely-meshed sub-transmission systems

In this paper, the selection of circuit breakers for a densely-meshed sub-transmission system with relatively short transmission lines is investigated. The results highlight the significance of modeling the load at the end of lines for accurately calculating the transient recovery voltage (TRV) following the short-circuit current interruption. According to IEEE standards, assuming load modeling at the end of the transmission lines can result in a maximum discrepancy of 20 % in the calculated TRV. Supposing that the load modeling leads to a moderating effect on the calculated TRV, the difference is considered as a safety margin, and load modeling is ignored. Nevertheless, the results presented here illustrate that this assumption strongly depends on characteristics of the studied network and the load type. In a network possessing the characteristics outlined in this paper, even a passive load as small as 15 % of the nominal capacity can significantly moderate the calculated TRV, with impacts reaching up to 38 %. Conversely, modeling an active load may result in a more severe TRV than if it were disregarded. The simulation results indicate that for networks with transmission lines longer than 70 km, neglecting to model passive loads on the transmission lines still yields sufficiently accurate calculations of TRV.

Critical solder joint in insulated gate bipolar transistors (IGBT) power module for improved mechanical reliability

This investigation identifies the critical solder joint in a typical Insulated Gate Bipolar Transistor (IGBT) module and provided new knowledge on how operating thermal loads degrade IGBT-attach, Diode-attach, and Substrate solder joints in the device. SolidWorks software is used to create three realistic 3-D Finite Element (FE) models of the typical IGBT module used in this investigation. In-service operating power and IEC 60068–2-14 thermal cycles are implemented in ANSYS mechanical package to simulate the response of the three solder joints in the FE models to the load cycles. The solder in the joints is lead-free alloy of 96.5% tin, 3% silver, and 0.5% copper (SAC305) composition. The SAC305 material properties are modelled as time and temperature dependent with Anand's visco-plastic model employed as the constitutive model. Results show that the key degradation mechanism of solder joints in IGBT module are stress, plastic strain, and strain energy magnitudes. Accumulated plastic strain in the joints is found the predominant damage factor. Critical solder joint in the module depends on the load cycle the device experiences. IGBT-attach solder joint is critical in active power load cycle. Substrate solder joint degraded most in passive thermal cum combined passive thermal and active power load cycles.

Mild untreated hypercholesterolaemia affects mechanical properties of the Achilles tendon but not gastrocnemius muscle

Tendon xanthoma and altered mechanical properties have been demonstrated in people with familial hypercholesterolaemia. However, it is unclear whether mild, untreated hypercholesterolaemia alters musculotendinous mechanical properties and muscle architecture. We conducted a case-control study of adults aged 50 years and over, without lower limb injury or history of statin medication. Based on fasting low-density lipoprotein (LDL) cholesterol levels, 6 participants had borderline high LDL (>3.33 mmol/L) and 6 had optimal LDL cholesterol (<2.56 mmol/L). Using shear wave elastography, shear wave velocity (SWV) of the Achilles tendon and gastrocnemius medialis muscle (a proxy for stiffness), along with muscle fascicle length and pennation angle were measured under four passive tensile loads (0, 0.5, 1.0, 1.5 kg) applied via a pulley system. Differences between groups were found for tendon SWV but not muscle SWV, fascicle length or pennation angle. Participants with hypercholesterolaemia showed greater SWV (mean difference, 95 % CI: 2.4 m/s, 0.9 to 4.0, P = 0.024) compared to the control group across all loads. These findings suggest that adults with mild hypercholesterolaemia have increased tendon stiffness under low passive loads, while muscle was not affected. Future research is needed to confirm findings in a larger cohort and explore the impact of hypercholesterolaemia on tendon fatigue injury and tendinopathy.

Arm Back Support Suit (Abs-Suit) for Parcel Delivery With a Passive Load Redistribution Mechanism

Arm Back Support Suit (Abs-Suit) for Parcel Delivery With a Passive Load Redistribution Mechanism

Voltage margin control for offshore multi-use platform integration

This paper discusses a multiterminal direct current (MTDC) connection proposed for integration of offshore multi-use platforms into continental grids. Voltage source converters (VSC) were selected for their suitability for multiterminal dc systems and for their flexibility in control. A five terminal VSC-MTDC which includes offshore generation, storage, loads and ac connection, was modeled and simulated in DigSILENT Power Factory software. Voltage margin method has been used for reliable operation of the MTDC system without the need of fast communication. Simulation results show that the proposed system was able to maintain constant dc voltage operation during fluctuations in the generation and changes in the demand. Moreover, it was able to secure power supply to passive loads during loss of a dc voltage regulating terminal and to perform a dispatch scheme where it is possible to buy, sell or store energy attending to the price in the electricity market

Multistability of synchronous modes in a multimachine power grid with a common load and their global and non-local stability

The purpose of this work is studying the dynamics of the power grid consisting of an arbitrary number of synchronous generators supplying a common passive linear load. We focus on searching the conditions for the existence and stability of synchronous modes, i.e. the main operating modes of a power grid. The possibility of the existence of non-synchronous (quasi-synchronous and asynchronous) modes is investigated. Methods. To study the dynamics of a power grid we use the effective network model in the form of an ensemble of globally coupled nodes-generators. The state of every node is described by the swing equation. The approach for reducing the effective network to the network with a hub topology (star topology) is proposed. We use numerical methods to construct a partition of the parameter space into areas with different operating modes of the power grid. Results. The conditions for the existence, stability and multistability of synchronous modes are obtained. The main characteristics of these modes are considered, such as the power supplied by generators to the grid and the distribution of currents along transmission lines. We constructed the partition of the power gird parameter space into areas with different dynamics. Conclusion. The power grid consisting of an arbitrary number of synchronous generators supplying a common passive linear load has been studied. We shown the presence of two types of synchronous modes: homogeneous and inhomogeneous. The first is characterized by equal powers and currents flowing through all load supply paths except one. The second provides another additional path, which differs from the others in current and transmitted power. Moreover, the currents flowing along the same path, but in various modes, differ. The presence of high multistability of inhomogeneous synchronous modes has been established. The possibility of coexistence of homogeneous and inhomogeneous synchronous modes, as well as quasi-synchronous and asynchronous modes, is shown. In the power grid parameters space we found areas corresponding both the existence of only synchronous modes and their coexistence with quasi-synchronous and/or asynchronous modes.

IOT based Energy Monitoring for Practical Loads using NodeMCU

Electrical energy monitoring is increasingly important nowadays for residential and commercial usage. The energy meters are installed in consumer’s houses to track their energy usage. There are many chances of human mistakes for every electricity consumer while recording the manual energy meter reading in their houses. Also, the consumer does not have updated information about current electricity usage in each hour, day, and month. To overcome the above problems, the system is developed to remotely monitor from any world location using the NodeMCU and Arduino IDE. The energy monitoring is carried out by using the Node MCU, Arduino IDE, and PZEM-004T sensor. The PZEM-004T module is coupled to the Arduino controller. The sensor module receives a signal from the CT coil which is connected to load. The load parameters such as voltage current power etc., are measured and transferred to the Arduino. A NodeMCU ESP8266 is utilized as a Wi-Fi chip system. By using a Wi-Fi connection and the internet, the acquired data is sent to Thing Speak to save in the cloud to monitor the measured parameters remotely. The power analyzer instrument is also used to measure the real-time parameters consumed by the load which is used to cross verification and compare with the sensor measuring parameters. The passive load resistance, inductance, and 100-watt lamp loads are experimentally connected and tested. The load consumed electrical parameters such as current, voltage, power, power factor, real power, and frequency are monitored in online. Energy monitoring online may reduce the consumer's mistakes by recording the parameters and consumers can know each hour, day, and month's energy consumption up to date according to their usage.

Investigation of Passive Pile Groups’ Responses Induced by Combined Surcharge-Induced and Excavation-Induced Horizontal Soil Loading

Excessive lateral forces and the deformation of pile groups caused by adjacent surcharge loading and excavation can potentially lead to the failure or collapse of nearby pile foundations. This paper presents a simplified analytical method to investigate the lateral displacement of passive pile groups caused by combined surcharge-induced and excavation-induced horizontal soil loading and validates it by utilizing two published centrifuge tests and numerical modeling. Firstly, the passive load resulting from surcharge-induced horizontal soil loading is determined using the improved formula of Boussinesq and the theory of local plastic deformation. The additional horizontal force exerted on the pile axis subjected to excavation-induced horizontal soil loading is also taken into account using the Mindlin solution. Furthermore, the shielding effect between pile groups is also proposed to analyze the response of a laterally loaded pile group due to excavation unloading. Secondly, according to the Pasternak foundation model of soil–pile interaction, the equilibrium differential equations are solved by the finite difference method. Finally, parametric analyses are undertaken to evaluate the behavior of different constraints on the pile head and surcharge procedure. The results demonstrate that the capped-head pile groups can provide greater restraint compared to the free-head groups for the lateral displacement of pile groups. The front pile experiences greater forces than the rear one in passive pile groups as a result of the smaller soil pressure on the rear pile. Additionally, increasing the horizontal stiffness of the capped head with fully fixed ends can significantly decrease the horizontal deformation of the pile groups.

Super-twisting based sliding mode control of hydraulic actuator without velocity state

This paper provides a novel surface design and experimental evaluation of a super-twisting algorithm (STA) based control for hydraulic cylinder actuators. The proposed integral sliding surface allows to track a sufficiently smooth reference without using the velocity state which is hardly accessible in the noisy hydraulic systems. A design methodology based on LMI’s is given, and the STA gains are designed to be adjusted by only one free parameter. The feasibility and effectiveness of the proposed control method are shown on a standard hydraulic test bench with one linear degree of freedom and passive load, where a typical motion profile is tracked with a bounded average error below 1% from the total drive effective output.

Aero-structural rapid screening of new design concepts for offshore wind turbines

The development of large-scale wind turbines is challenged by loads, mass, and cost growth, and more flexible blades that impact power and tower clearance. Further, the long-duration design iterations with standard-sequential-multidisciplinary processes challenge the development of new timely and robust designs. To overcome these limitations and answer open questions of large-scale wind turbines, we develop and demonstrate an aero-structural rapid screening (ASRS) design approach. ASRS uses optimization techniques, emulates a baseline controller, produces detailed blade, tower, and monopile models, and provides fast aerodynamic, structural, and economic results. Blade deflection is introduced as a design variable to achieve load-aligned designs as a function of wind speed for passive load alleviation. To illustrate the approach, a large set of 25 MW rotors for offshore and fixed-bottom wind turbines are studied for variations in blade pre-cone, load alignment via blade deflection, and upwind vs. downwind configurations. These designs vary in number of blades, blade length, axial induction factor, and airfoil family. We demonstrate that blade deflection can be designed to maximize energy capture and minimize turbine mass. ASRS is demonstrated to identify trends and trade-offs that are useful to down-select to options to be studied further using aero-servo-elastic simulations with high-fidelity control design.

Passive aeroelastic study of large and flexible wind turbine blades for load reduction

In this paper, passive aeroelastic coupling of wind turbine blades for load reduction is realized by introducing bending-twist coupling (BTC) and geometric sweep coupling (GSC). The BTC is implemented by composite fiber off-axis of the blade spar cap, and the GSC is achieved by defining sweep curves of the blade reference axis. To investigate the passive coupling effect and load reduction of the large and flexible blades, the IEA 15 MW blades are considered. BTC are introduced into the three-dimensional finite element (FE) models and the residual stiffness coefficient is obtained. Meanwhile, geometrically exact beam theory (GEBT) is used to build the flexible blade. Both BTC and GSC are introduced into the beam model, and the effect elastic deformation on blade load is also considered. Multi-objective optimization (MOO) process of rotating blades for load reduction is proposed under steady-state rated conditions. The results show that the highest coupling efficiency can be obtained when the fiber off-axis angle is between 12° and 15°. The BTC of the blade can reduce the load of blade root with a small fiber off-axis angle. Meanwhile, the GSC can further reduce the axis torque. Compared with the initial design of IEA 15 MW steady-state rotating blade, the maximum thrust, flapwise moment and axis torque of the blade can be reduced by 8.8 %, 13.4 % and 22.9 % respectively.

КОМБІНОВАНЕ РЕГУЛЮВАННЯ КОМУТОВАНИМИ КОНДЕНСАТОРАМИ Й ВЕНТИЛЬНИМ ПЕРЕТВОРЮВАЧЕМ НАПРУГИ АСИНХРОННОГО ГЕНЕРАТОРА АВТОНОМНО ПРАЦЮЮЧОЇ МІНІ-ГЕС

The principles of operation and a static simulation model of the power-generating equipment of the autonomous power supply source based on a hydroelectric unit with a 275 kVA induction generator and a combined capacitor-inverter excitation system supplying a symmetrical passive load have been developed. The initial excitation of the generator is carried out by a bank of capacitors of the initial excitation. During low power demand the generator voltage is kept constant by adjusting the reactive power of the semiconductor converter, and at high loads, the voltage is adjusted as a result of the switching of additional capacitor banks. The developed methodology for performance analysis the pro-posed power supply source is based on the IG equivalent circuit. Computations of the static characteristics of the gen-erator operating with a constant rotor speed were carried out and the obtained static characteristics were analyzed for two set values of the load power factor. Ref. 5, fig. 4, table.

Functional Characterization of the A414G Loss-of-Function Mutation in HCN4 Associated with Sinus Bradycardia

Patients carrying the heterozygous A414G mutation in the HCN4 gene, which encodes the HCN4 protein, demonstrate moderate to severe bradycardia of the heart. Tetramers of HCN4 subunits compose the ion channels in the sinus node that carry the hyperpolarization-activated ‘funny’ current (If), also named the ‘pacemaker current’. If plays an essential modulating role in sinus node pacemaker activity. To assess the mechanism by which the A414G mutation results in sinus bradycardia, we first performed voltage clamp measurements on wild-type (WT) and heterozygous mutant HCN4 channels expressed in Chinese hamster ovary (CHO) cells. These experiments were performed at physiological temperature using the amphotericin-perforated patch-clamp technique. Next, we applied the experimentally observed mutation-induced changes in the HCN4 current of the CHO cells to If of the single human sinus node cell model developed by Fabbri and coworkers. The half-maximal activation voltage V1/2 of the heterozygous mutant HCN4 current was 19.9 mV more negative than that of the WT HCN4 current (p &lt; 0.001). In addition, the voltage dependence of the heterozygous mutant HCN4 current (de)activation time constant showed a −11.9 mV shift (p &lt; 0.001) compared to the WT HCN4 current. The fully-activated current density, the slope factor of the activation curve, and the reversal potential were not significantly affected by the heterozygous A414G mutation. In the human sinus node computer model, the cycle length was substantially increased, almost entirely due to the shift in the voltage dependence of steady-state activation, and this increase was more prominent under vagal tone. The introduction of a passive atrial load into the model sinus node cell further reduced the beating rate, demonstrating that the bradycardia of the sinus node was even more pronounced by interactions between the sinus node and atria. In conclusion, the experimentally identified A414G-induced changes in If can explain the clinically observed sinus bradycardia in patients carrying the A414G HCN4 gene mutation.

Analyzing and supporting mental representations and strategies in solving Bayesian problems.

Solving Bayesian problems poses many challenges, such as identifying relevant numerical information, classifying, and translating it into mathematical formula language, and forming a mental representation. This triggers research on how to support the solving of Bayesian problems. The facilitating effect of using numerical data in frequency format instead of probabilities is well documented, as is the facilitating effect of given visualizations of statistical data. The present study not only compares the visualizations of the 2 × 2 table and the unit square, but also focuses on the results obtained from the self-creation of these visualizations by the participants. Since it has not yet been investigated whether the better correspondence between external and internal visualization also has an effect on cognitive load when solving Bayesian tasks, passive and active cognitive load are additionally measured. Due to the analog character and the proportional representation of the numerical information by the unit square, it is assumed that the passive cognitive load is lower when using the unit square as visualization than when using the 2 × 2 table. The opposite is true for active cognitive load.

Fuel sloshing-induced effects on the dynamic response of a scaled research wing demonstrator

Fuel sloshing inside aircraft wing tanks is not currently considered as a means of passive loads alleviation due to the lack of maturity of modelling tools and overall understanding of vertical sloshing. In this work, a scaled research wing demonstrator is presented, designed for the study of fuel sloshing inside an aircraft wing-representative model. An experimental campaign was conducted to examine the impact of fuel sloshing on the vertical dynamics of a scaled aircraft wing demonstrator, investigating the influence of excitation amplitude, filling level, baffle geometry, spanwise liquid position, and dihedral angle. It was found that the sloshing of the liquid in the fuel tank causes significant energy dissipation following step release excitation, maximized in the 40-60% filling range depending on the dihedral angle. The sloshing-induced damping also varies with the amplitude of excitation, with maximum added damping ratio of 0.038 achieved earlier in the motion at larger excitation amplitudes. The spanwise distribution of the liquid was found to have the strongest effect on the sloshing-induced damping, with the baffles' main impact being through the compartmentalization of the tank. Solid baffles that maintain favorable liquid distribution can increase the damping effect, while perforated baffles are not as effective. This work indicates that by considering the fuel dynamics rather than the fuel equivalent dry mass during the aircraft wing design, the net damping may be increased, leading to lighter wing structure designs.

Give a little to get a little: A DER Bill of Rights and Responsibilities provides the social license for participation and control in DER-dominated grids - an Australian example

When distributed solar photovoltaic systems (PV) provide the majority of supply in electricity grids, system operators and network service providers require increased control of customer-owned assets to maintain system security, reliability and equity. Several programs of reform for distributed energy resources (DER) in Australia, USA and Europe have emphasised the importance of placing customers at the centre of any energy transition, but this has occurred against a haphazard backdrop of proposed solar export taxes, decreasing feed-in tariffs, time-varying export incentives and updated inverter standards. Absent is a conversation of how the social contract of connecting to the electricity grid is evolving beyond the passive expectation of electricity supply of the 19th and 20th centuries to a two-way engagement that must support fairness for both DER-owners and non-owners in grids that are at times dominated by DER. This paper proposes a first attempt at a ‘DER Bill of Rights and Responsibilities’ to provide a template for this required social-license, distinguishing between passive grid participation (passive loads, traditional use, PV self-consumption) and active grid participation (grid interaction for remuneration). Guiding principles of fairness are presented with practical definitions for implementation, referencing existing instruments including inverter standards, network connection agreements, reliability standards, and central ancillary service markets. The intent is that clarity on rights to self-consumption and passive participation will support customer trust in the responsibilities for active DER integration and control. We highlight how proposed rights are already being breached regularly in Australia, as an example jurisdiction, before outlining a pathway to enshrine them for a DER-dominated future with broad sector endorsement. These questions are critical for Australia to address now; other jurisdictions will likely be required to do so in the near future.