External Power Requirement Research Articles

Review on heat transfer augmentation in helically coiled tube heat exchanger

In contemporary times, Helical tube heat exchangers (HTHXs) have gained significant prominence in energy-related sectors, frequently finding application in industrial and technical settings. Their impact on overall system efficiency and size is substantial. A comprehensive review addressing passive heat transfer enhancement methods in HTHXs is notably absent. This paper justifies its significance by providing a recent and systematic review of available passive methods. The passive approach offers advantages such as the absence of external power requirements and lower operational costs compared to active methods.This paper differentiates active and passive approaches. Studies collectively indicate a noteworthy progression in heat transfer enhancement in HTHXs. The paper meticulously evaluates passive methods like fins, inserts, geometry modifications, and baffles. Both experimental and numerical studies focus on improving heat transfer in HTHXs. However, further exploration is necessary to understand the negative effects of pressure drop in tube-side flow. Papers covering trends in future research should also prioritize the development of geometric designs for HTHX surfaces, potentially incorporating materials coatings to enhance heat transfer further. The authors present insightful issues and ideas that they estimate deserving of additional investigation in subsequent research endeavors

Experimental study on thermal performance of a novel serpentine-looped flat microchannel heat pipe

The pulsating heat pipe is an efficient heat transfer element widely used in a variety of applications due to the simple wickless structure and no external power requirements. Increasing the number of pipe turns can enhance the pulsation, but reduce the structural compactness. A new type of serpentine-looped flat microchannel heat pipe (SLFMHP) is proposed with numerous turns by series connection of flow channels and good thermal contact by large flat surface. The thermal performance of SLFMHP is experimentally investigated and compared with that of the copper pulsating heat pipe. Results show that the minimum thermal resistance of SLFMHP is 0.036 K/W, 80 % smaller than 0.19 K/W of the copper pulsating heat pipe. The maximum effective thermal conductivity of SLFMHP reaches 37400 W/(m·K), five times of 7233 W/(m·K) of the copper pulsating heat pipe. The sensitivity to inclination angle has also been reduced with thermal resistance at 0° improved by over 90 %. As the inclination angle increases, the thermal resistance decreases first sharply and then slowly, and the turning point is defined as the critical pulsation angle, about 15° and 8° with the filling ratio of 20 % and 40 %, respectively. The SLFMHP can provide a possible solution for the demand of the thermal control systems with miniaturization, light weight and high heat transfer capability.

In vitro hemodynamic performance of a blood pump for self-powered venous assist in univentricular hearts

Univentricular heart anomalies represent a group of severe congenital heart defects necessitating early surgical intervention in infancy. The Fontan procedure, the final stage of single-ventricle palliation, establishes a serial connection between systemic and pulmonary circulation by channeling venous return to the lungs. The absence of the subpulmonary ventricle in this peculiar circulation progressively eventuates in failure, primarily due to chronic elevation in inferior vena cava (IVC) pressure. This study experimentally validates the effectiveness of an intracorporeally-powered venous ejector pump (VEP) in reducing IVC pressure in Fontan patients. The VEP exploits a fraction of aortic flow to create a jet-venturi effect for the IVC, negating the external power requirement and driveline infections. An invitro Fontan mock-up circulation loop is developed and the impact of VEP design parameters and physiological conditions is assessed using both idealized and patient-specific total cavopulmonary connection (TCPC) phantoms. The VEP performance in reducing IVC pressure exhibited an inverse relationship with the cardiac output and extra-cardiac conduit (ECC) size and a proportional relationship with the transpulmonary pressure gradient (TPG) and mean arterial pressure (MAP). The ideal VEP with fail-safe features provided an IVC pressure drop of 1.82 ± 0.49, 2.45 ± 0.54, and 3.12 ± 0.43 mm Hg for TPG values of 6, 8, and 10 mm Hg, respectively, averaged over all ECC sizes and cardiac outputs. Furthermore, the arterial oxygen saturation was consistently maintained above 85% during full-assist mode. These results emphasize the potential utility of the VEP to mitigate elevated venous pressure in Fontan patients.

A Self-Powered UV Photodetector With Ultrahigh Responsivity Based on 2D Perovskite Ferroelectric Films With Mixed Spacer Cations.

Self-powered photodetectors (PDs) have the advantages of no external power requirement, wireless operation, and long life. Spontaneous ferroelectric polarizations can significantly increase built-in electric field intensity, showing great potential in self-powered photodetection. Moreover, ferroelectrics possess pyroelectric and piezoelectric properties, beneficial for enhancing self-powered PDs. 2D metal halide perovskites (MHPs), which have ferroelectric properties, are suitable for fabricating high-performance self-powered PDs. However, the research on 2D metal halide perovskites ferroelectrics focuses on growing bulk crystals. Herein, 2D ferroelectric perovskite films with mixed spacer cations for self-powered PDs are demonstrated by mixing Ruddlesden-Popper (RP)-type and Dion-Jacobson (DJ)-type perovskite. The (BDA0.7 (BA2 )0.3 )(EA)2 Pb3 Br10 film possesses, overall, the best film qualities with the best crystalline quality, lowest trap density, good phase purity, and obvious ferroelectricity. Based on the ferro-pyro-phototronic effect, the PD at 360nm exhibits excellent photoelectric properties, with an ultrahigh peak responsivity greater than 93 A W-1 and a detectivity of 2.5 × 1015 Jones, together with excellent reproducibility and stability. The maximum responsivities can be modulated by piezo-phototronic effect with an effective enhancement ratio of 480%. This work will open up a new route of designing MHP ferroelectric films for high-performance PDs and offers the opportunity to utilize it for various optoelectronics applications.

The effects of crank power and cadence on muscle fascicle shortening velocities, muscle activations and joint-powers during cycling.

Whilst people typically chose to locomote in most economical fashion, during bicycling they will, unusually, chose cadences that are higher than metabolically optimal. Empirical measurements of the intrinsic contractile properties of the vastus lateralis (VL) muscle during submaximal cycling suggest that the cadences that people self-selected (SSC) might allow for optimal muscle fascicle shortening velocity for the production of knee extensor muscle power. It remains unclear, however, whether this is consistent across different power outputs where the SSC varies. We examined the effect of cadence and external power requirements on muscle neuromechanics and joint powers during cycling. VL fascicle shortening velocities, muscle activations and joint-specific powers were measured during cycling between 60 and 120rpm (including SSC), while participants produced 10%, 30%, and 50% of peak maximal power. VL shortening velocity increased as cadence increased but was similar across the different power outputs. Although no differences were found in the distribution of joint powers across cadence conditions, the absolute knee joint power increased with increasing crank power output. Muscle fascicle shortening velocities increased in VL at the SSC as pedal power demands increased from submaximal towards maximal cycling. A secondary analysis of muscle activation patterns showed minimized activation of VL and other muscles near the SSC at the 10% and 30% power conditions. Minimization of activation with progressively increasing fascicle shortening velocities at the SSC may be consistent with the theory that the optimum shortening velocity for maximizing power increases with intensity of exercise and recruitment of fast twitch fibers.

RetroV2X: A new vehicle-to-everything (V2X) paradigm with visible light backscatter networking

The Vehicle-to-Everything (V2X) technology has become essential with the increasing interest in intelligent transportation systems. It connects multiple vehicles and infrastructure by digitizing road traffic signs, signals, and other facilities and arranging sensing devices. However, conventional V2X solutions, such as Celluar Vehicle-to-Everything (C-V2X), have been slow to deploy due to their high cost, external power requirement, and dependence on Internet backhaul connectivity. Recently, Visible Light Backscatter Communication (VLBC) technology has emerged as a promising solution to overcome the practical issues of conventional V2X technologies. This paper presents RetroV2X, a protocol designed to support a networked VLBC-based V2X system that facilitates the transmission of road sensory data between vehicles and road infrastructure. We have designed several mechanisms, including backoff, virtual ID assignment, and excitatory carrier sensing, to handle different types of collisions, namely downlink, synchronous uplink, and asynchronous uplink collisions. Overhear and relay mechanisms are also designed to improve the performance at high vehicle densities. Our evaluation demonstrates that RetroV2X is capable of meeting the needs of V2X applications in typical rural road, town road, and highway scenarios with varying road sign densities, vehicle densities, and velocities.

Experimental and analytical study on the stability of a low aspect ratio single-phase natural circulation loop coupled to a parabolic trough collector

Use of passive heat transport systems in renewable energy eliminates operator and external power requirements, thereby reducing the cost. Hence, a horizontal heater and horizontal cooler rectangular natural circulation loop (NCL) of low L/D (110) and aspect ratio (0.54) is coupled to a parabolic trough in the present work. Experimental investigations of the loop's steady state and stability characteristics were carried out at various powers corresponding to the solar irradiances using water as the heat transfer fluid. SolTrace was used to determine the heat loads at different direct normal irradiance (DNI) for the selected loop and trough dimensions. The upper threshold for stability was experimentally observed for the first time and reported here. Stability analysis carried out for different loop diameters revealed that the power at which the upper threshold of instability occurs reduces significantly with increase in loop diameter, enabling its observation in the low-pressure low temperature loop employed in the present study. Stabilizing techniques like orifice insertion and loop inclinations were also studied in detail. The results showed stability at higher heat loads (> 350 DNI), while the instability at lower heat loads can be curbed using an orifice (β = 0.5) or a loop inclination (> 4°). The small inclination can eliminate multiple steady state solutions and hence stabilizes the loop. Besides, the reduction in natural circulation flow rate with inclination is much smaller compared to the orifice making its heat transport capability higher. Additionally, the steady state results were validated with 1-D analytical model giving a good match.

A novel post-combustion CO2 capture design integrated with an Organic Rankine Cycle (ORC)

Fossil fuel-based power plants are the significant sources of CO2 emitted into the atmosphere that significantly affect global warming. While these power plants provide the robustness of the grids, even with the fast development of renewable electricity, utilization of CO2 Capture and Storage (CCS) technologies is one of the best solutions to reduce their emissions and environmental risks. However, one of the most significant drawbacks of these technologies is their highest costs related to their energy consumption as well as the specific requirements of the solvents, which prevalently impact their adaptation. Among these technologies, Post-Combustion CO2 Capture (PCC) processes are widely used in the case of the power plant. This research develops an onshore Aqueous Post-Combustion CO2 Capture (APCC) process with water as a physical solvent to achieve a high CO 2 capture ratio with low energy consumption. The flue gas stream from a power plant flows into APCC, which can capture 72 kton/year of CO2. About 97.4% of CO2 was captured in the process with a 49.5% electricity production to consumption ratio (22.74 MWh/ton CO2) The captured CO2 is then delivered into a CO2 injection well to be used for Enhanced Oil Recovery (EOR) purpose with 15Mpa, 30 °C, and 80 mol% purity. Two scenarios were considered to decrease the external power requirements (1) the electricity production to consumption ratio is increased to 58.2% by adding a Hydro-Pump to the process; (2) coupling an Organic Rankine Cycle (ORC) with R125 working fluid to the process and using sensitivity analysis to gain the best thermodynamic conditions to increase the power production to consumption ratio to 80%. By considering both scenarios, the parasitic power is decreased by 52.78–28.44% and the net power production from the NGCC power plant is increased to 18.604 MW. Finally, Pinch Design Method (PDM) is used to reduce the Operating Cost of the process by the best utility selection from 2.48 M$/year to 0.945 M$/year, and the best Heat Exchanger Network (HEN) design in terms of the lowest Capital Cost at 4.71 M$/year was designed.

Bioinspired shark skin-based liquid metal triboelectric nanogenerator for self-powered gait analysis and long-term rehabilitation monitoring

Real-time gait monitoring is crucial for neuromuscular diagnosis and rehabilitation of neuromuscular ailments. However, the existing wearable sensors for gait analysis suffer from several drawbacks, such as external power requirement, poor sensitivity, short-term stability, and professional operator requirement, which restrict their applicability outside clinical settings. Here, a next-generation self-powered solid-liquid triboelectric nanogenerator-based flexible wearable sensor is developed. The proposed sensor is composed of a highly resilient liquid metal encapsulated within an innovative bio-mimicked shark skin-like microstructure embedded on the Ecoflex surface. The unique surface morphology imparts hydrophobicity to the solid triboelectric layer, which prevents the liquid metal adhesion during sensing and facilitates highly sensitive real-time monitoring of signals and long-term stability. The as-designed low-cost, highly scalable self-powered sensor, which is also compatible with diverse detection strategies, provides an on-demand user-friendly point-of-care gait detection and rehabilitation monitoring system with significant applications in personalized health care and sports science.

ℏω versus ℏk: dispersion and energy constraints on time-varying photonic materials and time crystals [Invited

Photonic time-varying systems have attracted significant attention owing to their rich physics and potential opportunities for new and enhanced functionalities. In this context, the duality of space and time in wave physics has been particularly fruitful to uncover interesting physical effects in the temporal domain, such as reflection/refraction at temporal interfaces and momentum-bandgaps in time crystals. However, the characteristics of the temporal/frequency dimension, particularly its relation to causality and energy conservation ( ℏ ω is energy, whereas ℏ k is momentum), create challenges and constraints that are unique to time-varying systems and are not present in their spatially varying counterparts. Here, we overview two key physical aspects of time-varying photonics that have only received marginal attention so far, namely temporal dispersion and external power requirements, and explore their implications. We discuss how temporal dispersion, an inherent property of any physical causal material, makes the fields evolve continuously at sharp temporal interfaces and may limit the strength of fast temporal modulations and of various resulting effects. Furthermore, we show that changing the refractive index in time always involves large amounts of energy. We derive power requirements to observe a time-crystal response in one of the most popular material platforms in time-varying photonics, i.e., transparent conducting oxides, and we argue that these effects are almost always obscured by less exotic nonlinear phenomena. These observations and findings shed light on the physics and constraints of time-varying photonics, and may guide the design and implementation of future time-modulated photonic systems.

Highly Sensitive Self‐Powered H2 Sensor Based on Nanostructured Thermoelectric Silicon Fabrics

AbstractSelf‐powered sensors running on small differences of temperature are considered promising candidates to cover the increasing demand of sustainable and maintenance‐free wireless sensor networks for the Internet of Things (IoT). Under this context, a cost‐effective and self‐powered hydrogen thermoelectric sensor is presented here as a proof of concept for battery‐less IoT nodes. The device is based on low‐density paper‐like fabrics made of functionalized thermoelectric silicon nanotubes able to harvest energy from the heat released by exothermic reactions, such as the hydrogen catalytic oxidation. This gives an accurate value of the reacting gas concentration without any external power requirement. Experimental results confirm that this self‐powered sensor can autonomously measure concentrations as low as 250 ppm of hydrogen in air while generating power densities up to 0.5 μW cm−2 for 3% H2 at room temperature that can be eventually used to store or send the reading. Due to the universality of the concept, this new class of devices will positively contribute toward the development of other advanced self‐powered sensor nodes in the advent of the Internet of things to be used in different safety scenarios.

Battery-free short-range self-powered wireless sensor network (SS-WSN) using TENG based direct sensory transmission (TDST) mechanism

Wireless Sensor Networks (WSNs) bring the basis that the development of the Internet of Things (IoTs) relies on. However, external power requirement restricts the widespread applications of WSNs. Triboelectric nanogenerator (TENG) has been a promising candidate for energy harvesting and self-powered sensing, but most of the reported TENG-based WSNs need to store energy in a capacitor first and then power the wireless modules without a continuous sensing capability simultaneously. In this work, a battery-free short-range self-powered wireless sensor network (SS-WSN) is proposed by using TENG-based direct sensory transmission (TDST). By leveraging a mechanical switch or diode-switch combination, enhanced output and boosted frequency of TENG signal have been achieved by instantaneous discharging in a short period, initiating the potential for direct signal transmission without additional wireless modules and external power suppliers. Different from others' works, the stable resonant frequency is used to realize the force-sensing function with high sensitivity (434.7 Hz.N−1), in which case a wireless real-time electronic scale is demonstrated. Additionally, by varying the connections of the textile TENGs or the capacitance of an external capacitor for distinguishable resonant frequencies generation, the multiple-freedom-degree 2D toy car control, and 3D VR drone control are demonstrated with a single coil.

The use of super-critical carbon dioxide as the working fluid in enhanced geothermal systems (EGSs): A review study

Naturally-occurring high-temperature geothermal energy resources contribute significantly to the world’s emerging energy demand by allowing renewable and clean power generation, and the technology of enhanced geothermal systems (EGSs) continues to progress at deeper levels, providing the ability to extract heat stored in deep underground at 2–5 km depths, which would have previously been considered impractical. Water-based EGSs are fairly well established, and a number of research studies have been carried out on the performance of water as the working fluid in geothermal reservoirs. Besides, the applicability of super-critical carbon dioxide (ScCO2) as the working fluid in EGSs by replacing water was recently investigated by research studies due to a number of advantages accompanied in CO2 as the working fluid in EGSs. The aim of this review study is to comprehensively investigate the applicability of ScCO2 as a working fluid in EGSs by summarising the recent research studies conducted on the operation of CO2-based geothermal systems. The study is further intended to highlight the advantages of ScCO2 in the EGS environment compared to conventional water-based methods. Of the advantages, a reduction of the external power requirement for the pumping of ScCO2 due to enhanced injectivity and flowability is the most attractive. In terms of heat extraction, higher mass flowrates can be achieved using ScCO2 as a working fluid, depending on the density-to-viscosity ratio, and the ratio is doubled with ScCO2 compared to water in the temperature range of 200–250 °C. Moreover, an accelerated energy recovery can be achieved through the higher thermal extraction rates of ScCO2, which are 50% greater than for water. Importantly, ScCO2 has the ability of inducing an interconnected fracture network with multiple secondary branches under comparatively low breakdown pressures compared to water. ScCO2 being a linear molecule with lower viscosity has the percolation ability into microcracks of the rock matrix, and thereby, the pressurisation of these microcracks induce multiple flow paths long the rock matrix by interconnecting the microcracks. In addition, the use of ScCO2 eliminates the problems associated with silica dissolution followed by precipitation, takes place in surface piping, heat exchangers and other surface equipment, because dry ScCO2 is less reactive in hot-dry reservoirs. However, in water-based EGSs, enhanced reactivity of water with the increase of pH accelerates the dissolution and precipitation of minerals, and is a critical issue in water-based EGSs. The enhanced reactivity of ScCO2 in the presence of pore fluid may also affect the long-term integrity of EGSs, because it alters the internal pore structure, due to the dissolution and precipitation of primary and secondary rock minerals, resulting in altered porosity and permeability, which ultimately affect the energy extraction process.

Underwater Robotic Welding of Lap Joints with Sandwiched Reactive Multilayers: Thermal, Mechanical and Material Analysis

ABSTRACTUnderwater welding using reactive materials pre-deposited at the junction surfaces as a self-contained, in-situ ignitable heat source mitigates external power and gas supply requirements. Consequently, lending itself to robotic implementation eliminating the cost along with health and safety hazards of human welder-divers. This project reports on lap joining of aluminum sheets with sandwiched commercial reactive Ni-Al multilayers that are perforated to allow for melt fusion under compression upon ignition, in saline and deionized water as well as air for comparison. Finite-element thermal simulations are employed to study the resulting welding temperature field and melt conditions. Infrared pyrometry and thermocouple measurements during welding were used to validate the computational simulations. The lap joints are subjected to standard shear testing, and comparable compliance, strength and toughness values of the welds are assessed for underwater and dry joints. Scanning electron (SEM) of the weld sections reveal rapidly melting and solidifying microstructures of the parent metal, with minimal melt flow and perfusion of nickel aluminide aggregates from the reacted multilayers, and no signs of cavitation.

Mathematical analysis and coordinated current allocation control in battery power module systems

As the major energy storage device and power supply source in numerous energy applications, such as solar panels, wind plants, and electric vehicles, battery systems often face the issue of charge imbalance among battery cells/modules, which can accelerate battery degradation, cause more energy loss, and even incur fire hazard. To tackle this issue, various circuit designs have been developed to enable charge equalization among battery cells/modules. Recently, the battery power module (BPM) design has emerged to be one of the promising solutions for its capability of independent control of individual battery cells/modules. In this paper, we propose a new current allocation method based on charging/discharging space (CDS) for performance control in BPM systems. Based on the proposed method, the properties of CDS-based current allocation with constant parameters are analyzed. Then, real-time external total power requirement is taken into account and an algorithm is developed for coordinated system performance control. By choosing appropriate control parameters, the desired system performance can be achieved by coordinating the module charge balance and total power efficiency. Besides, the proposed algorithm has complete analytical solutions, and thus is very computationally efficient. Finally, the efficacy of the proposed algorithm is demonstrated using simulations.

MEMS-Based acoustic sensors for fluid mechanics and aeroacoustics

This talk presents the development of several microelectromechanical systems (MEMS)-based acoustic transducer technologies for fluid mechanics and aeroacoustics applications. Specifically, this presentation will focus on several aluminum nitride piezoelectric MEMS dynamic pressure sensors and microphones. These devices offer the promise of reducing cost, improving performance, and increasing mounting flexibility over existing conventional microphone technologies. Specifically, a transducer with no external power requirement has a key advantage for a large-channel count, widespread deployment. The modeling and design aspects of these devices are reviewed. First, the electroacoustic transduction is predicted via piezoelectric composite plate theory. Lumped element models are then synthesized to describe the dynamic characteristics of the transducer diaphragm and the cavity/vent structure. Constrained nonlinear design optimization using a sequential quadratic programming scheme is then performed to determine the design parameters. Representative results for several applications will then be presented. Finally, unresolved technical issues are summarized for future sensor development.

Technology-derived storage solutions for stabilizing insulin in extreme weather conditions I: the ViViCap-1 device

ABSTRACTBackground: Injectable life-saving drugs should not be exposed to temperatures <4°C/39°F or >30°C/86°F. Frequently, weather conditions exceed these temperature thresholds in many countries. Insulin is to be kept at 4–8°C/~ 39–47°F until use and once opened, is supposed to be stable for up to 31 days at room temperature (exception: 42 days for insulin levemir). Extremely hot or cold external temperature can lead to insulin degradation in a very short time with loss of its glucose-lowering efficacy.Methods: Combined chemical and engineering solutions for heat protection are employed in ViViCap-1 for disposable insulin pens. The device works based on vacuum insulation and heat consumption by phase-change material. Laboratory studies with exposure of ViViCap-1 to hot outside conditions were performed to evaluate the device performance.Results: ViViCap-1 keeps insulin at an internal temperature < 29°C/84.2°F for a minimum of 12 h without external power requirement, even when constantly exposed to an outside temperature of 37.8°C/100°F. Bringing the device into an ambient temperature < 26°C/78.8°F reverses the phase-change process and ‘recharges’ the device for further use.Conclusions: ViViCap-1 performed within its specifications. The small and convenient device maintains the efficacy and safety of using insulin even when carried under hot weather conditions.

Magnetically Actuated Microfluidic Transistors: Miniaturized Micro-Valves Using Magnetorheological Fluids Integrated With Elastomeric Membranes

We present a magnetically actuated microfluidic transistor (valve), an on-chip micro-valve that uses magnetorheological fluids micropatterned onto an elastomeric membrane to develop an ultra-compact solution for digital control of microfluidic circuits. We simulated the micro-valves theoretically and also characterized micro-fabricated devices experimentally. We simulated the effects of channel and valve geometry on the deformability of the valve. We experimentally characterized the effects of channel and valve geometry on the ability to reversibly close channels fully. We characterized the microfabricated valves in the flow rate range of 0.02–1 $\mu \text{l}$ /min. Among the various kinds of valves examined, for lower flow rates, circular valves with a 700 $\mu \text{m}$ diameter in 300 $\mu \text{m}$ width channel, and in higher flow rates, rectangular valves 700 $\mu \text{m}$ wide in the same channel show the best ability in terms of valve closure and response time. The fabrication and the integration of the proposed valve are compatible with a range of polymer microfabrication technologies having the advantage of simple fabrication, small size, and no external power requirement. These valve structures can be promising solutions for pumping and active flow control for portable analytical instrumentation, point-of-care diagnostic devices, and even wearable microfluidic devices. [2015-0296]

On the Design of a Solar-Panel Receiver for Optical Wireless Communications With Simultaneous Energy Harvesting

This paper proposes a novel design of an optical wireless communications (OWC) receiver using a solar panel as a photodetector. The proposed system is capable of simultaneous data transmission and energy harvesting. The solar panel can convert a modulated light signal into an electrical signal without any external power requirements. Furthermore, the direct current (DC) component of the modulated light can be harvested in the proposed receiver. The generated energy can potentially be used to power a user terminal or at least to prolong its operation time. The current work discusses the various parameters which need to be considered in the design of a system using a solar panel for simultaneous communication and energy harvesting. The presented theory is supported with an experimental implementation of orthogonal frequency division multiplexing (OFDM), thus, proving the validity of the analysis and demonstrating the feasibility of the proposed receiver. Using the propounded system, a communication link with a data rate of 11.84 Mbps is established for a received optical signal with a peak-to-peak amplitude of 0.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Evaluation of a Numerical Methodology to Estimate Pedestrians’ Energy Consumption and PM Inhalation

The aim of this research work is to define and evaluate a new methodology for pedestrians, in order to evaluate the total PM potential inhaled dose (PPID) and the energy consumption for different trips, according to PM concentration levels, pedestrian activity (external power requirements) and minute ventilation, considering street topography (slope), walking speed and pedestrian characteristics (weight, age, gender).This work introduces the Pedestrian Specific Effort (PSE) modal analysis. It is based on real-world measurements of urban trips to discretize VE and VO2 according to external power requirements due to speed and slope. Trip segmentations is also introduced. Each segment has similar attributes for pedestrian speed, traffic characterization or road grade and also similar power requirements which enables the establishment of a relationship between external power and minute ventilation.This methodology was applied to a case study in Lisbon and the results were validated with experimental data. A portable laboratory was used to acquire the necessary information to characterize pedestrian trips (instant speed, PM concentration, GPS coordinates, etc.).Results show, as far as this methodology is concerned, good estimates of PM potential inhaled dose and energy consumption, when compared to in situ measurements, on a second by second basis, varying between -6 to 6% in PPID and -9% to 8% regarding energy consumption. These results indicate that the discretization performed (using PSE and segments) constitutes a good approach to translate real-world trips.