Passive System Research Articles

Water desalination using PV panels based on boiling and evaporation

The annual share of water in Egypt has decreased to approximately 500 m3 per capita, while the annual water scarcity level is 1000 m3 per capita, which indicates that Egyptians are at a high risk of living. A domestic desalination unit based on solar energy was designed, built, and tested to solve this problem in remote areas that do not have access to fresh water or electricity but have access to salty water. The desalination unit has a new design that depends on boiling salty water using photovoltaic solar cells and then condensing the water vapor through a heat exchanger to obtain freshwater. This new design has not been implemented before and can compete with the solar stills used for domestic applications. The output of the developed unit was compared to those of passive and active solar stills that have been developed and built. The new desalination design produced almost the same amount of daily fresh water, 4 Liter/day, compared to the other solar stills (2–4.75 Liter/day), but the cost per unit volume of the new design, 31 $/m3, is less by 30% compared to the best performing solar still, 44.55 $/m3, which produces only 2 Liter/day. The price of the distilled water produced by the new design was 75% lower than the market price at the time of conducting the experiments. Converting a Solar still from a passive system, that is, operating only during sunlight, to an active system operating day and night improves the water productivity rate. However, this is not feasible because of the added accessories that increase the initial cost, consequently increasing the cost of desalination.

Electronic Properties of F, Cl and H Atoms Adsorbed on CsPbI3(110) Surface

The electronic properties of the CsPbI3 surface are calculated by using first-principles calculations. Through calculating adsorption energy of CsPbI3 passivated by Cl, F and H atoms, it is found that adsorption energy values of CsPbI3 (110) surface passivated by H atoms fluctuate less, they are less sensitive to the adsorption position, and the adsorption is stable. Through calculating surface states of passivation system, it is found that F and H atoms have quite good passivation effect, and the Fermi level of passivation system increases and enters the forbidden band, indicating that the passivation effect is relatively ideal. Passivation effect of Cl atoms are poor, a new shallow acceptor defect states appeared at the bottom of the conduction band. This defect level could trap carriers and weaken the carrier migration ability, which is a disadvantage of Cl passivation system. Through the charge density difference and Bader charges, it is found that the F and H atoms get more electrons from the I atom, which is beneficial to the passivation of the surface states.

Flexible resource optimal allocation strategy for distribution system resilience improvement under failure uncertainty

Extreme disasters have led to huge economical losses to the power system and posed a huge threat to the stable supply of electric energy. Especially for traditional passive distribution network systems, failures of transmission lines, towers, and other equipment will cause large-scale power outages and huge economic losses. In order to improve the ability of the power system to deal with extreme weather disasters, this paper proposes an optimal configuration strategy for the distribution network backup power resource oriented to resilience improvement, considering the uncertainty of equipment failure caused by disasters in the case of a known disaster range. The location and capacity of backup resources can be properly configured to reduce the load shedding of the power distribution network during the disaster process, thereby improving the resilience of the distribution network. The method proposed in this paper is modeled as a two-stage stochastic programming, which includes mix-integer constraints. In the first stage, the optimization problem confirms the capacity and location of the flexible resources. In the second stage, the operational constraints and costs of load shedding are considered. The resilience enhancement method is verified on the improved IEEE-33 node system, and the result shows that the method proposed in this paper can effectively enhance the resilience of the urban power network.

Online optimal tuning of fuzzy PID controller using grey wolf optimizer for quarter car semi-active suspension system

In order to reduce vibration and increase ride comfort, this article utilizes a system of quarter-car suspension integrated with a Fuzzy PID controller. To build and improve the Fuzzy PID controller for the semi-active suspension system used in quarter cars, using a novel meta-heuristic technique known as Grey Wolf Optimizer (GWO). Here the magnetorheological damper (MR) fluid with the Fuzzy PID controller was examined to optimize using the GWO algorithm. With the GWO technique and the integral of time absolute error (IAE) as a fitness function, the three gain parameters of the Fuzzy PID controller – Kp, Ki, and Kd– have been optimally set. The suggested approach has additional advantages for the optimization of functions with three variables, including simplicity in implementation, quick convergence traits, and superior computational capabilities. This work is significant, to the best of the author’s knowledge there is no optimization method using GWO to online tune a Fuzzy PID controller for a semi-active suspension system. The optimal output parameters of the controller can be updated online in real-time by GWO. The performance of the proposed controller was examined by assessing the root mean square (RMS) values and peak-to-peak (PTP) values of body displacement and body acceleration under various road profiles. To ensure that the intelligent controller was of the highest caliber, an online test rig was constructed. Results from simulations and online experiments demonstrated that the Fuzzy GWO PID controller significantly improved ride comfort under a variety of road conditions when compared to the Fuzzy PID controller and passive suspension system.

Rheotaxis of sperm: Hydrodynamics behavior of human sperm in a passive microfluidic system

Rheotaxis of sperm: Hydrodynamics behavior of human sperm in a passive microfluidic system

Design Constraints Generalization for Series-Stacked Buffer-Based Active DC Links

Series-stacked buffer (SSB) based active DC links aim to increase power density by replacing bulky DC link capacitor with series connection of significantly lower valued capacitor and auxiliary bidirectional DC/AC converter. SSB design constraint describing quantitative relation between passive components values and system power rating was established to achieve minimal remaining DC link voltage ripple magnitude. This letter generalizes the above requirement, revealing that allowing non-minimum magnitude of residual DC link voltage ripple releases other design constraints, yielding a more optimal solution in terms of full-rating capacitance utilized and/or auxiliary bidirectional DC/AC converter volt-ampere rating. Experimental results validate the proposed methodology, matching corresponding analytical predictions.

Outcomes from water drop impact on hydrophobic meshes

Understanding water drop impact on meshes is valuable to design passive systems for atmospheric water collection. By investigating water drop impact on hydrophobic and superhydrophobic surfaces, here, we identify the different drop impact outcomes and build outcome maps within the pertinent parameter spaces, based on Weber number and contact angles. Furthermore, we quantitatively evaluate critical factors such as the captured volume and spray characteristics of the penetrating liquid and also measure the drop rebound time, reporting that full rebound occurs on superhydrophobic meshes surfaces even at high We numbers, as the Cassie–Baxter wetting state is maintained.

Evaluasi Sistem Proteksi Kebakaran Pada Bangunan Gedung Rumah Sakit Umum Daerah Pulang Pisau

Fire is an incident that results in loss in the form of material or non-material, there are several factors that cause electrical fires, the element of intent and the lack of preparedness of the surrounding community in facing and dealing with the danger of fire and the lack of fire protection system facilities and infrastructure. Evaluation of the fire protection system refers to the Pd-T-11-2005-C regulation concerning Fire Safety Inspections of Buildings, the method used is interviews, direct observation and measurements at the location. The results of this research are the Reliability Value of Building Safety Systems for Landing Equipment Components 22.60%, Safety Suggestions 18.25%, Active Protection Systems 5.9% and Passive Protection System Components 9.36%. And the overall calculation results from the KSKB obtained a value of 56.11%

Investigation of Heat Exchanger Performance in The Heating Tank Section of Loop FASSIP 03 NT

The Passive System Simulation Facility (FASSIP) loop is an experimental test facility for a passive cooling system to recover the residual heat from decay produced by the reactor core during accident conditions. The Heating Tank Section (HTS) is one of the components of the FASSIP 03 NT facility. This component is equipped with a heat exchanger, 3 types of heat exchangers can be applied to HTS. Namely heat exchangers of the Straight Pipe Heat Exchanger (SPHE) type, the Straight Pipe Fins Heat Exchanger (SPFHE) type, and the Helical Pipe Heat Exchanger (HPHE) type. A modification was made to increase the efficiency of HTS, namely replacing the electric heater on the HTS from a ceramic band heater type to an immersion heater type. With this modification, it is necessary to know the performance of the heat exchanger on HTS and its speed in reaching operational temperature. The HPHE-type heat exchanger is more efficient than the SPHE-type and SPFHE-type heat exchangers. The HPHE-type heat exchanger has a much larger length of 5.5 m, so the thermal resistance (Rth) is very small, namely 0.003926 ℃/W. To reach the working fluid temperature in the range of 50 – 90 ℃, the HPHE-type heat exchanger requires 35 – 86 minutes.

35 years of lessons learned designing, building, and monitoring passive treatment systems for mining influenced water (part 1)

35 years of lessons learned designing, building, and monitoring passive treatment systems for mining influenced water (part 1)

Rewetting drained peatlands through subsoil infiltration stabilises redox-dependent soil carbon and nutrient dynamics

Centuries of drainage have stimulated peat decomposition. To counteract the resulting increase in greenhouse gas emission and land subsidence in Dutch agricultural peatlands, passive and active subsurface infiltration (SSI) systems have been developed for peatland rewetting. Here, we studied the effects of SSI systems on groundwater levels, porewater composition and redox potential in four drained peatlands in the Netherlands to determine how soil processes are affected, especially carbon and nutrient dynamics. For three years, groundwater levels were measured continuously, and porewater samples were collected 8–10 times per year in paired SSI (active and passive) and control plots. SSI plots had higher summer groundwater levels and less seasonal fluctuation in groundwater levels than control plots. Redox potential and porewater composition in control plots reflected dominance of oxidation processes during dry periods in the upper soil layers, whereas SSI plots showed dominance of reduction processes in these layers throughout the year. These differences between control and SSI plots were strongest at locations with active SSI systems. Our results show that SSI systems can be effective measures to raise and stabilise groundwater levels in drained peatlands, which results in more stable redox zonation and dominance of anaerobic soil processes, especially during dry periods and when active SSI systems are applied. On the short term, a switch from oxic to anoxic conditions can cause mobilisation of phosphorus and ammonium, while on the longer term the application of SSI can lead to substantial change in carbon and nutrient dynamics. Understanding the full effects of implementing SSI systems and other mitigation measures in drained peatlands is important before they are applied on a large scale.

GREEN ARCHITECTURE AND ENERGY EFFICIENCY: A REVIEW OF INNOVATIVE DESIGN AND CONSTRUCTION TECHNIQUES

Green architecture and energy efficiency have become imperative considerations in contemporary construction practices, driven by the escalating global concern over environmental degradation and energy consumption. This paper provides a comprehensive review of innovative design and construction techniques employed in green architecture to enhance energy efficiency. The study delves into the integration of sustainable design principles, emphasizing the importance of minimizing the ecological footprint of buildings. Various strategies such as passive design, green roofs, and efficient insulation systems are explored to create structures that harness natural resources intelligently. These techniques not only reduce energy consumption but also contribute to a healthier indoor environment. Innovative construction materials play a pivotal role in green architecture, with a focus on utilizing recycled and locally sourced materials. The paper scrutinizes emerging technologies like bio-concrete and self-healing materials, which not only enhance structural resilience but also embody eco-friendly attributes. Furthermore, the utilization of advanced building systems, such as smart grids and energy-efficient HVAC systems, is discussed for optimizing energy performance throughout the lifecycle of a building. The review also highlights the significance of renewable energy sources, with an emphasis on incorporating solar panels, wind turbines, and other sustainable energy solutions into architectural designs. The integration of these technologies not only promotes energy self-sufficiency but also contributes to the overall reduction of greenhouse gas emissions. In conclusion, this paper encapsulates a comprehensive exploration of the symbiotic relationship between green architecture and energy efficiency. By examining cutting-edge design and construction techniques, the study seeks to provide insights that can inform and inspire future practices in the construction industry, fostering a sustainable approach that addresses both environmental concerns and the growing demand for energy-efficient infrastructure.
 Keywords: Energy, Green Architecture, Construction Technique, Innovative Design, Review.

Comprehensive Assessment of the Seismic Performance of an Innovative Hybrid Semiactive and Passive State Control System for a Low-Degree-of-Freedom Structure Using Real-Time Hybrid Simulation

The dynamic performance of base isolation systems provides an effective means to reduce the seismic vulnerability of buildings. However, large displacements in the base isolation during seismic events pose a major challenge for this control system. Recently, novel control systems have been implemented to control and reduce the excessive displacements. This study presents an evaluation of the seismic performance of unconnected-fiber-reinforced elastomeric isolators (U-FREI) and variable orifice damper (VOD) devices used together as a hybrid control system for a low-degree-of-freedom reference structure by employing real-time hybrid simulation (RTHS) testing technique. This physical cybernetic testing methodology allows a dynamic system of interest to be substructured into two components: numerical and experimental. In this study, the numerical substructure corresponds to a 2-degree of freedom model, representing a reference structure, and an experimental substructure was formed using the hybrid control system described. To develop an interface between the two substructures, a horizontal transfer system (HTS) was implemented and coupled with a vertical transfer system (VTS). Using RTHS, the performance of the reference structure and the hybrid control system was evaluated under six seismic events: CAM, CAT, El Centro, Loma Prieta, Pizarro, and Chihuahua, at a maximum acceleration of 0.10 g (0.981 m·s−2). The experimental behavior of the hybrid control system allows the reference structure to reduce its maximum drift by more than 24% compared to the fixed structure. Finally, the performance and accuracy of the RTHS tests were calculated.

Self-Powered Passive Adaptive Control of Pitch Angle and Betz-Shaped Wind Tunnel

Owing to both the high cost and the complexity, for small turbines, the control of pitch angle is usually not a option though it could keep turbine working in high efficiency zone while wind speed changes. In order to solve this problem, a self-powered passive adaptive control system (SPACS) for pitch angle adjustment has been developed. Together with this SPACS idea, a Betz-shaped wind tunnel has also been developed which can reduce the size and running cost significantly if compared with conventional wind tunnels. In this paper the main technical principles will be presented together with some conceptual sketches and initial results.

Analysis of irreversibility on nanofluid flow through porous medium considering shape, dispersion and melting effects

This study is conducted to explore the impact of thermal dispersion and melting on the natural convective nanofluid (nickel zinc ferrite + SAE 20W-40 motor oil) flow over a stretching sheet in a Darcy porous medium. An irreversibility analysis has also been performed using the second law of thermodynamics. The fundamental nonlinear partial differential equations (PDEs) are converted into a system of dimensionless nonlinear ordinary differential equations (ODEs) through Lie group similarity transformations and then solved by employing the spectral local linearization method implemented in MATLAB software. It is noteworthy to highlight that the validation results indicate a strong concurrence with existing findings in previously published literature. After simulation, it is specified that the thermal dispersion disrupts the entropy (by 63.7%) and enhances the surface friction. Likewise, the heat transfer rate improves by 1.5% with the melting effect and 58.7% with the Darcy number. The results indicate that the brick-shaped particles exhibit a higher rate of heat transfer and lower entropy production. Further, this work has many uses such as, core, microwave, and biomedical applications like tumor treatments, bone plate surgeries, EMI (electromagnetic interfaces), electronics cooling, and aerodynamic extrusion processes, in the design of passive ventilation systems.

Modeling and simulation of photovoltaic powered battery-supercapacitor hybrid energy storage system for electric vehicles

Energy storage is crucial for the powertrain of electric vehicles (EVs). Battery is a key energy storage device for EVs. However, higher cost and limited lifespan of batteries are their significant drawbacks. Therefore, to overcome these drawbacks and to meet the energy demands effectively, batteries and supercapacitors (SCs) are simultaneously employed in EVs. A solar photovoltaic (PV) powered battery-supercapacitor (SC) hybrid energy storage system has been proposed for the electric vehicles and its modeling and numerical simulation has been carried out in MATLAB Simulink. The SC is used to supply the peak power demand and to withstand strong charging or discharging current peaks. It also improved the battery pack's durability and extended its life. Different topologies of battery and SC have been explored and their capacity to manage the battery stress is assessed. The passive topology is found to be the most suitable for the proposed model due to its ease of implementation and absence of control scheme. A hybrid topology is used to share the power across batteries, supercapacitors and the PV system. In the proposed hybrid energy storage system, a sudden load on the battery is shifted towards the capacitor and thus, the battery heating is reduced, that ultimately improved the vehicle performance and reduced the charging time. In addition, the supercapacitor stored a lot of energy in a short period of time and delivered more power to the load without experiencing any life-span deterioration. The results indicated that employing a passive DC-DC converter and hybrid energy storage system (HESS) reduced the battery power by 52 %, while the passive HESS system reduced the motor current by 94 %. The supercapacitor also recovered 51 % more energy while starting and can offer peak power more efficiently than a battery.

Movement patterns during gait initiation in older adults with various stages of frailty: a biomechanical analysis

BackgroundGait initiation is challenging for older individuals with poor physical function, particularly for those with frailty. Frailty is a geriatric syndrome associated with increased risk of illness, falls, and functional decline. This study examines whether spatial and temporal parameters of gait initiation differ between groups of older adults with different levels of frailty, and whether fear of falling, and balance ability are correlated with the height of lifting the food during gait initiation.MethodsSixty-one individuals aged > 65 years, classified by Fried frailty phenotype, performed five self-paced gait initiation trials. Data was collected using a three-dimensional passive optical motion capture system, consisting of 10 cameras with the ability to perceive reflective markers, and two force plates. The total duration of gait initiation and the duration of its four sub-phases, the first step length, and the maximum foot clearance during the first step were derived, and compared statistically between groups. Additionally, an association analysis was conducted between foot clearance and fear of falling, and confidence in balance in older individuals.ResultsFrail individuals had significantly longer unloading durations, and total durations of gait initiation compared to non-frail older adults. Additionally, they had shorter first step lengths compared to non-frail older adults. Pre-frail older adults also showed shorter steps compared to the non-frail group. However, there were no significant differences between groups for the maximum foot clearance during the first step. Nevertheless, the maximum foot clearance of older individuals correlated significantly with their fear of falling and confidence in balance.ConclusionOlder adults with reduced physical function and signs of frailty mainly display longer duration of gait initiation and decreased first step length compared to non-frail older adults. The release phase is decreased as the double support phase is prolonged in frail patients. This information can guide the development of specialized exercise programs to improve mobility in this challenging motion between static and dynamic balance.

Investigation of the Enhancement of Heat Transfer in a Flat Plate Solar Collector With a Corrugated Tube Under Thermosiphon Effect

Abstract The development of new technologies for energy generation and use has been increasing significantly. In this projection, the use of flat solar collectors to convert solar energy into thermal energy through water heating for residential and commercial purposes has grown due to the potential reduction of up to 40% in electrical energy consumption promoted by these devices. A promising but underexplored area in engineering is the study of the intensification of heat transfer in these devices by changing the dimensional and constructive characteristics of the elevation tubes, especially through a numerical approach by passive systems that operate under the thermosiphon effect. Thus, this work aims to investigate, by using computational fluid dynamics (CFD), the heat transfer process in a flat plate solar collector with a concentric plate to the elevation tube, evaluating different diameters, angles of inclination, and slope corrugation profiles subjected to a constant heat flux. The numerical modeling considers a single-phase, incompressible, permanent, three-dimensional, and laminar flow, in addition to the Boussinesq approximation. The results showed that significant increases in the heat transfer rate can be achieved with absorber plates in comparison to those configurations without absorber plates. Moreover, the increase in the tube diameter allowed gains of up to 5.1% in the heat transfer rate, while the increase in the angle of inclination did not promote significant improvements. The triangular profile R10 P20 configuration increased the Nusselt number by 8%, while the R5 P20 configuration promoted a 25% gain in thermo-hydraulic performance.

Leveraging COVID-19 Vaccine Safety Monitoring in Ethiopia and Pakistan to Enhance System-Wide Safety Surveillance.

The rapid development, introduction, and global uptake of COVID-19 vaccines required countries to have strong pharmacovigilance systems in place to monitor and address adverse events following immunization (AEFIs). These systems provide timely data on vaccine safety that support decisions about the potential risks of vaccine adverse events relative to the benefit of disease prevention. In Ethiopia, the monitoring system was limited by the lack of data being submitted through its passive surveillance system, delays in investigating serious adverse events and conducting causality assessments, and the lack of reporting to the World Health Organization (WHO) global database, VigiBase. In Pakistan, the pharmacovigilance system lacked reporting requirements and guidance documentation, regulatory policies were insufficient, and staff lacked the capacity to evaluate AEFI reports. Several interventions were implemented in both countries to improve pharmacovigilance systems and processes necessary to collect, analyze, and report AEFIs from health care facilities to the national level and facilitate the use of global and national electronic reporting tools. In addition, Pakistan improved the regulatory policy environment and engaged vaccine manufacturers and private sector health facilities in AEFI reporting for the first time in the country. Outcomes include an increased number of COVID-19 vaccine-related AEFIs reported and causality assessments completed, which means that potential safety issues were being analyzed more quickly, comprehensively, and accurately. The number of AEFI reports submitted to VigiBase by Pakistan's regulatory authority more than quintupled from approximately 5,000/quarter in 2021 to 28,555/quarter in 2022. In Ethiopia, by October 2022, 44,000 AEFI reports had been received, and 40 causality assessments completed. In both countries, timely AEFI data review and analysis led to prompt recommendations and regulatory actions, highlighting the far-reaching implications of strengthening the country-level pharmacovigilance systems. These strengthened systems are now in place for use with all vaccines.

Data-Driven Modeling of the Nonlinear Dynamics of Passive Lower-Limb Prosthetic Systems

Abstract Modeling the nonlinear dynamics of prosthetic feet is an important tool for linking prosthesis mechanical properties to end-user outcomes. There has been a renewed interest in data-driven modeling of dynamical systems, with the development of the Extended Dynamic Mode Decomposition with control (eDMDc) and the Sparse Identification of Nonlinear Dynamics with Control (SINDYc). These algorithms do not require prior information about the system, including mechanical configuration, and are data-driven. The aim of this study was to assess the feasibility and accuracy of applying these data-driven algorithms to model prosthesis nonlinear load response dynamics. Different combinations of a dynamic response foot, a hydraulic ankle unit, and three shock-absorbing pylons of varying resistance were tested loaded and unloaded at three orientations reflecting critical positions during the stance phase of walking. We tested two different data-driven algorithms, the eDMDc, with two different kernels, and the SINDYc, which regresses the coefficients for a nonlinear ordinary differential equation. Each algorithm was able to model the nonlinear prosthesis dynamics, but the SINDYc outperformed the eDMDc methods with a root mean square error across orientations < 1.50 mm and a maximum error in peak displacement of 1.28 mm or 4% relative error. From the estimated SINDYc governing equation of the system dynamics, we were able to simulate different mechanical behavior by systematically varying parameter values, which offers a novel foundation for designing, controlling, and classifying prosthetic systems ultimately aimed at improving prosthesis user outcomes.