Electrical Research Articles

Cooperative aggregation of gold nanoparticles on phospholipid vesicles is electrostatically driven.

Gold nanoparticles (AuNP) are known to aggregate on the surface of lipid vesicles, yet the molecular mechanism behind this phenomenom remains unclear. In this work, we have investigated the binding behaviour of AuNPs, synthesized with pulsed laser ablation, to phospholipid vesicles under varying conditions of ionic strength (KCl concentration) and NP to vesicle ratios. Our observations reveal a strong influence of electrolyte concentration on AuNP aggregation mediated by vesicles. Notably, cluster formation is observed even at less than one AuNP per vesicle ratio at low enough ionic strengths. These results evidence a binding mechanism governed by electrostatic attraction with a distinct cooperative behaviour at very low salt concentrations, resulting in a significant increase in nanoparticle clustering. This behaviour is quantitatively analysed through a model that incorporates the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, considering the electrical double layer attraction between dissimilar, non-oppositely charged objects. This study not only provides insight into the fundamental understanding of nanoparticle-vesicle interactions but also suggests potential strategies for controlling nanoparticle assembly in biological and synthetic systems by tuning the ionic strength.

Numerical Investigation of the Thermal Performance of Air-Cooling System for a Lithium-Ion Battery Module Combined with Epoxy Resin Boards

Lithium-ion batteries (LIBs) have the lead as the most used power source for electric vehicles and grid storage systems, and a battery thermal management system (BTMS) can ensure the efficient and safe operation of lithium-ion batteries. Epoxy resin board (ERB) offers a wide range of applications in LIBs due to its significant advantages such as high dielectric strength, electrical insulation, good mechanical strength, and stiffness. This study proposes an air-cooled battery module comprised of sixteen prismatic batteries incorporating an ERB layer between the batteries. To compare the performance of the ERB-based air-cooling system, two other air-cooling structures are also assessed in this study. Three-dimensional numerical models for the three cases are established in this paper, and the heat dissipation processes of the battery module under varying discharge rates (1C, 2C, and 5C) are simulated and analyzed to comprehensively evaluate the performance of the different cooling systems. Comparative simulations reveal that incorporating ERB into the battery assembly significantly reduces battery surface temperatures and promotes temperature uniformity across individual batteries and the entire pack at various discharge rates. Notably, under 5C discharge conditions, the ERB-based thermal management system achieves a maximum battery surface temperature increase of 16 °C and a maximum temperature difference of 8 °C between batteries. Additionally, this paper also analyzes the impact of battery arrangement on air-cooling system performance. Therefore, further optimization of the structural design or the integration of supplementary cooling media might be necessary for such demanding conditions.

Bifurcation Diagrams of Nonlinear Oscillatory Dynamical Systems: A Brief Review in 1D, 2D and 3D

We discuss 1D, 2D and 3D bifurcation diagrams of two nonlinear dynamical systems: an electric arc system having both chaotic and periodic steady-state responses and a cytosolic calcium system with both periodic/chaotic and constant steady-state outputs. The diagrams are mostly obtained by using the 0–1 test for chaos, but other types of diagrams are also mentioned; for example, typical 1D diagrams with local maxiumum values of oscillatory responses (periodic and chaotic), the entropy method and the largest Lyapunov exponent approach. Important features and properties of each of the three classes of diagrams with one, two and three varying parameters in the 1D, 2D and 3D cases, respectively, are presented and illustrated via certain diagrams of the K values, −1≤K≤1, from the 0–1 test and the sample entropy values SaEn>0. The K values close to 0 indicate periodic and quasi-periodic responses, while those close to 1 are for chaotic ones. The sample entropy 3D diagrams for an electric arc system are also provided to illustrate the variety of possible bifurcation diagrams available. We also provide a comparative study of the diagrams obtained using different methods with the goal of obtaining diagrams that appear similar (or close to each other) for the same dynamical system. Three examples of such comparisons are provided, each in the 1D, 2D and 3D cases. Additionally, this paper serves as a brief review of the many possible types of diagrams one can employ to identify and classify time-series obtained either as numerical solutions of models of nonlinear dynamical systems or recorded in a laboratory environment when a mathematical model is unknown. In the concluding section, we present a brief overview of the advantages and disadvantages of using the 1D, 2D and 3D diagrams. Several illustrative examples are included.

Cathode-Electrolyte Interphase Engineering toward Fast-Charging LiFePO4 Cathodes by Flash Carbon Coating.

Lithium iron phosphate (LiFePO4, LFP) batteries are widely used in electric vehicles and energy storage systems due to their excellent cycling stability, affordability and safety. However, the rate performance of LFP remains limited due to its low intrinsic electronic and ionic conductivities. In this work, an ex situ flash carbon coating method is developed to enhance the interfacial properties for fast charging. A continuous, amorphous carbon layer is achieved by rapidly decomposing the precursors and depositing carbon species in a confined space within 10 s. Simultaneously, different heteroatoms can be introduced into the surface carbon matrix, which regulates the irregular growth of cathode-electrolyte interphase (CEI) and selectively facilitates the inorganic region formation. The inorganic-rich, hybrid conductive CEI not only promotes electron and ion transport but also restricts parasitic side reactions. Consequently, LFP cathodes with fluorinated carbon coatings exhibited the highest capacity of 151 mAh g-1 at 0.2 C and 96mAhg-1 at 10 C, indicating their excellent rate capability over commercial LFP (58mAh g-1 at 10 C). This solvent-free, versatile surface modification is shown for other electrode materials, providing an efficient platform for electrode-electrolyte interphase engineering through a surface post-treatment.

Sandwich-structured polymer dielectrics exhibiting significantly improved capacitive performance at high temperatures by roll-to-roll physical vapor deposition

Electrostatic capacitors with ultrahigh power density are the key components in modern electrical and electronic systems. Polymers are preferred dielectrics for high-voltage electrostatic capacitors, however, unable to meet the ever-growing high-temperature requirements in emerging applications, such as electric vehicles, and photovoltaic power generation. In this work, sandwich-structured Polyphenylene sulfide (PPS) films with Al2O3 as the coating layer have been prepared by using roll-to-roll magnetron sputtering. The incorporation of Al2O3 coating layers enhances the potential barrier height at the electrode/dielectric interface, thereby impeding charge injection from electrodes and suppressing high-temperature electrical conduction. Consequently, the sandwich-structured PPS films demonstrate significantly improved breakdown strengths and enhanced capacitive performance at elevated temperatures compared to neat PPS films. The roll-to-roll magnetron sputtering process employed in fabricating these sandwich-structured dielectric films is highly compatible with large-scale capacitor film production. Thus, sandwich-structured PPS films hold promise in addressing the challenge of scalable fabrication of high-performance, high-quality polymer films required for high-temperature capacitive energy storage.

Impact of Artificial Intelligence on the Planning and Operation of Distributed Energy Systems in Smart Grids

This review paper thoroughly explores the impact of artificial intelligence on the planning and operation of distributed energy systems in smart grids. With the rapid advancement of artificial intelligence techniques such as machine learning, optimization, and cognitive computing, new opportunities are emerging to enhance the efficiency and reliability of electrical grids. From demand and generation prediction to energy flow optimization and load management, artificial intelligence is playing a pivotal role in the transformation of energy infrastructure. This paper delves deeply into the latest advancements in specific artificial intelligence applications within the context of distributed energy systems, including the coordination of distributed energy resources, the integration of intermittent renewable energies, and the enhancement of demand response. Furthermore, it discusses the technical, economic, and regulatory challenges associated with the implementation of artificial intelligence-based solutions, as well as the ethical considerations related to automation and autonomous decision-making in the energy sector. This comprehensive analysis provides a detailed insight into how artificial intelligence is reshaping the planning and operation of smart grids and highlights future research and development areas that are crucial for achieving a more efficient, sustainable, and resilient electrical system.

Comparative study on the impact of different E-J relations on the performance of resistive superconducting fault current limiters under high and low impedance faults in cryo-electric aircraft

To achieve the goal of zero emission in aviation, it is critical to advance electric aircraft technologies, especially in short to medium range flights. Superconducting fault current limiters (SFCLs) have shown promising potential in electric aircraft system as a protection solution to limit the peak of fault current. Many research works focused on the SFCL performance under low impedance faults, where the fault current is much higher than the nominal current and the SFCL will transit to normal (metal) state quickly. However, there are limited reports on investigating the SFCL reacting to high impedance faults for electric aircraft system, where the SFCL does not abruptly transit to normal state. In this paper, we built an electric-thermal coupled model in MATLAB which simulates the behaviour of a resistive type SFCL both under low and high impedance faults. We investigated three mathematical relations of local electric field E and local current density J representing the transition from superconducting state to normal state, both under high and low impedance fault. The three mathematical relations are classic E-J power-law, modified E-J power-law and two- stage E-J power law. The electric-thermal model of the SFCL incorporating all these three types of mathematical relations, respectively, have been used to calculate the SFCL responses under high and low impedance faults, and compared with each other, as well as testing results. The limited fault current, voltage drop, resistance and temperature variations in the SFCL are observed and analysed. The results have shown that the proposed SFCL model is able to accurately characterise a resistive type SFCL under both high impedance and low impedance fault.

Copper and Lithium Industrialization by Major Producing Countries for Mining Sustainability

This research objective is to analyze the prospects of copper and lithium industrialization for the mining sustainability of the world's major producing countries. An expo-facto design was used based on a documentary analysis, considering the world ranking of the top copper-producing countries, where Chile, Peru, China, and the Democratic Republic of Congo stand out, and regarding lithium production, Australia, Chile, China, and Argentina stand out. On a global level, the presence of South American countries with mining resources in exploration and extraction is relevant; in contrast, China, a mining country, not only extracts natural resources but has advanced in the value chain with competitive advantages and consequent economic development; for its part, the DR of Congo (Africa), has ascended in the copper extraction ranking. The motors and electrical systems of electromobility vehicles are manufactured with copper and the batteries with lithium, which contributes to the mitigation of greenhouse gas emissions and thereby to environmental sustainability. Furthermore, the correlation between copper and lithium demand for electric vehicles in a 2050 zero-emission scenario is strong. There are social conflicts, mainly over the use of water; therefore, it is necessary to implement mining policies that lead to sustainable development.

Operation of coupled power-gas networks with hydrogen refueling stations, responsive demands and storage systems: A novel stochastic framework

Because of factors such as low natural gas prices, low greenhouse gas emission and high efficiency has increased the penetration of natural gas-fired generators in electric power systems. Large gas consumption of gas-fired generators has caused intense interdependence of electricity and gas systems. Most often, the operational planning of power and gas systems is conducted through a co-optimisation model in which the total cost of electricity and gas systems is minimised and the constraints of both systems are considered. On the other hand, due to environmental concerns, the usage of fuel cell vehicles (FCVs) is increasing. Hydrogen refueling stations (HRSs) are needed for refueling FCVs. This paper puts forward a stochastic model for co-optimisation of wind-integrated power and gas systems, hosting HRSs, electric storage systems (ESS's) and responsive electricity and gas demands. The effect of ESS's, responsive demands, contingencies, wind uncertainties and demand response on operation of power-gas nexus is scrutinized. An incentive-based demand response program has been used for both electricity and gas demands. The case study is the Belgian gas network connected to the a 24-bus power system. The findings indicate that responsive electric demands reduce electric system cost by 9.4 %, while responsive gas demands reduce the gas network cost and total operation cost by 1 %. The contingency analysis on the power-gas nexus shows that single line outage contingencies in power system does not result in any demand shed and does not increase the operation cost of either electricity network or gas network.

Entropy generated nonlinear mixed convective beyond constant characteristics nanomaterial wedge flow

Background and objectiveNanomaterial flows at present have received much attention of the researchers. Such motivation stems for their utilization in pharmaceutical, industrial, petroleum, manufacturing and engineering applications including regenerative medicine, treatment of cancer, electronic device cooling, solar collector, mineral oil, antimicrobial agents, thermal storage system, transformer cooling and X-imaging etc. Higher thermal energy requirement in several electrical and mechanical systems is desired in recent time due to high advancement of science and technology. For important application here the stagnation point flow due to wedge with nonlinear convection is explored. For porous media, the Darcy-Forchheimer relation is considered. Characteristics of nanofluid is added by utilizing Buongiorno's model. Variable fluid characteristics are under consideration. Applied magnetic field is accounted. Energy expression comprises thermal radiation, Brownian motion, Ohmic heating, thermophoresis and heat generation. First order reaction and entropy rate are considered. MethodologyNonlinear differential expressions are changed into dimensionless ordinary systems through adequate transformations. The resultant nonlinear ordinary systems are solved through optimal homotopy analysis technique (OHAM). ResultsOutcomes for influential variables about temperature, velocity, concentration and entropy rate have been arranged. Here results show that for magnetic field the liquid flow and entropy rate have opposite scenarios. Thermal distribution and concentration have reverse effects for random motion variable while similar effect holds for thermophoresis parameter. Magnetic field and diffusion parameters contribute to augment entropy generation. Higher values of temperature dependent electrical conductivity variable lead to increase entropy rate. Thermal distribution for radiation and Eckert number is similar.

Fuzzy Modelling Algorithms and Parallel Distributed Compensation for Coupled Electromechanical Systems

Modelling and controlling an electrical Power Generation System (PGS), which consists of an Internal Combustion Engine (ICE) linked to an electric generator, poses a significant challenge due to various factors. These include the non-linear characteristics of the system’s components, thermal effects, mechanical vibrations, electrical noise, and the dynamic and transient impacts of electrical loads. In this study, we introduce a fuzzy modelling identification approach utilizing the Takagi–Sugeno (T–S) structure, wherein model and control parameters are optimized. This methodology circumvents the need for deriving a mathematical model through energy balance considerations involving thermodynamics and the non-linear representation of the electric generator. Initially, a non-linear mathematical model for the electrical power system is obtained through the fuzzy c-means algorithm, which handles both premises and consequents in state space, utilizing input–output experimental data. Subsequently, the Particle Swarm Algorithm (PSO) is employed for optimizing the fuzzy parameter m of the c-means algorithm during the modelling phase. Additionally, in the design of the Parallel Distributed Compensation Controller (PDC), the optimization of parameters pertaining to the poles of the closed-loop response is conducted also by using the PSO method. Ultimately, numerical simulations are conducted, adjusting the power consumption of an inductive load.

Studi Aliran Daya pada PT. PLN (Persero) UIWS2JB UP3 Jambi ULP Kotabaru Penyulang Palem dengan Menggunakan Software Electric Transient and Analysis Program (ETAP)

Planning in the use of components in a power system needs to be done correctly. The planning will affect the optimization of the system in distributing power. Suboptimal power distribution will have an impact on the continuity of the power being distributed. The analysis that will be carried out is a power flow analysis. This research was taken using data from ULP Kota Baru Penyulang Palem, the location of this research is located in the distribution system area of Jambi City, Jambi Province, with the connection center at Penyulang Palem which is located in Kota Baru District, Jambi City, Jambi Province. . KVA is used to measure the total power in an electrical system. Total power includes active power and reactive power, so KVA provides a more complete picture of the power requirements of an electrical system. In the KVA measurement, it is assumed that all loads connected on a single line are 85%, 90%, 95%. That the greater the assumed load of the transformer and the farther away from the source, the greater the voltage drop / the smaller the voltage The greater the resistance the smaller the voltage drop, if the smaller the resistance then the drop will be larger. The wider the cross-section, the smaller the strain drop. The highest measurement of all loads is 3918 kv at the base of the source located near the bus in JB1100 assuming all loads of 95%.

Assessment of grid electricity systems using the life-cycle carbon-emission model

The previous study developed a life-cycle carbon emissions (LCCE) algorithm in MS Excel. Despite improvements, a comprehensive approach is needed to conduct LCCE inventory analysis using current methods. This study diverges from existing research by assessing life-cycle carbon emissions inventory data of power generation and transmission systems on studied grids, considering component lifespans, recycling pollutants, and retirement rates. The life-cycle carbon emissions inventory analysis results improve understanding of power system environmental performance, aligning with stakeholders' objectives. This study aims to enhance the environmental performance of electric power systems in Kenya, Rwanda, and Tanzania by evaluating the life-cycle carbon emissions of power generation and transmission within their national grids. The selected grids are the right participants for the study, of non-renewable and renewable grid electricity generation mixes, due to their different environmental features, potential power trade, upcoming grid interconnection, and power transmission practises at various scales. The study applied a life cycle assessment method and simulated the learning patterns using RStudio. The data (emission factors and activity) has been collected from the reports (scientific and technical) and national utility actors. The presented results show that only Kenyan generation and transmission systems have the lifetime decarbonization performance relationship between renewable energy sources dominated power systems and non-renewable energy sources dominated power systems. A major challenge of this study has been the scarcity of primary data, leading to reliance on some secondary and external sources. Therefore, future research should consider the use of more internal and primary data sources, and the use of the most current data, including new technologies adopted from cradle-to-grave of the systems. This study's findings inform better system designs, policies, and plans for improved environmental performance in electrical power systems.

Synthesis and Characterization of Polythiophene and Polypyrrole

Polythiophene and polypyrrole are two well-known conducting polymers with diverse properties and several potential applications in sectors such as electronics, sensors, and energy storage. This paper delves further into the synthesis and analysis of polythiophene and polypyrrole. Polypyrrole and polythiophene were synthesized using chemical oxidative polymerization with suitable oxidizing agents. The methods employed to analyze these polymers included spectroscopy (UV-Vis, FTIR), thermal analysis (TGA, DSC), microscopy (SEM, TEM), and electrochemical analysis (cyclic voltammetry). Several features of polypyrrole and polythiophene production were investigated and linked to their electrochemical, thermal, morphological, and structural properties. We also discuss how these conducting polymers may be employed in electrical devices, sensors, and energy storage systems due to the unique properties revealed by their characterization. Polythiophene and polypyrrole may now be employed in a wide range of high-tech applications since their synthesis and properties are better known.

Dual-layer multi-mode energy management optimization strategy for electric vehicle hybrid energy storage systems

Dual-layer multi-mode energy management optimization strategy for electric vehicle hybrid energy storage systems

Predictive Modeling and Forecasting of Solar Power Generation Using Machine Learning Techniques

The purpose of this research study is to investigate the predictive modelling and forecasting of solar power generation by utilising a variety of machine learning approaches. The paper addresses the significant obstacle that is presented by the variable production of solar energy, which is a barrier to the effective incorporation of solar power into the network of electrical power distribution systems. This research investigates the application of machine learning models such as Bayesian Ridge Regression, Gradient Boosting, and Linear Regression. The research makes use of historical meteorological data and solar power output to investigate the application of these models. The effectiveness of these models in estimating the amount of solar energy that will be produced under a variety of different weather situations is being investigated. Based on the findings, it is evident that the application of machine learning techniques has the potential to considerably improve the accuracy of solar power projections. This, in turn, will facilitate better grid integration and promote wider adoption of solar energy products. Through the demonstration of the potential of advanced machine learning approaches in enhancing the reliability and efficiency of solar power generation, this study makes a contribution to the expanding body of literature on the forecasting of renewable energy sources.

Reversionary Control Modes for the Mitigation of Failures in a Partially Turboelectric Aircraft Propulsion System

Abstract In support of emission and fuel burn reduction goals, the aviation industry is actively pursuing the advancement of electrified aircraft propulsion (EAP) technology. This includes turboelectric and hybrid electric propulsion designs that combine gas turbine engine and electrical system hardware. Such architectures exhibit a high degree of coupling between subsystems. This drives the need for system-level control strategies to ensure the safe, coordinated, and efficient operation of all subsystems. The design and certification of any aircraft propulsion system requires that all potential subsystem failures are identified, and the hazards posed by these failures are appropriately mitigated. This requirement is particularly challenging for EAP systems due to their integrated nature. One approach to assist in EAP failure mitigation is the inclusion of automated reconfiguration capabilities within the propulsion control system. Such control modes, referred to as reversionary control modes, are designed to automatically detect failures and activate backup control modes upon failure detection. This paper covers the design and evaluation of reversionary control mode logic developed for a partially turboelectric propulsion concept. Test results from a real-time hardware-in-the-loop evaluation of the concept are also presented and discussed. The results show that the developed reversionary control logic can successfully detect and mitigate subsystem failures in a representative environment that includes actual electrical system hardware.

ESTUDIO DE DIFERENTES ALTERNATIVAS DE FUNCIONAMIENTO DE LOS GRUPOS EN LAS CENTRALES ELÉCTRICAS DE CANARIAS

Island electricity systems aim to adapt to the environmental expectations established by the European framework. For this reason, it is necessary to increase efforts to increase the penetration of renewables and optimize energy production. An extensive preliminary research study has been carried out on the current production system, its variables and its conditioning factors, with which a series of operating alternatives have been obtained that will optimize the energy production system through combustion technology (non-renewables) and combine them with the production of energy through renewable sources. renewables, complying both in dynamic response, security, scaling and integration with such systems, in terms of efficiency and power. The reduction of greenhouse gas emissions and the penetration of these renewable energies in the island's electricity systems will be increased. As has been proven in the research background, the usually established combination of power producing equipment is not the best to reduce pollution, and there are other possible combinations with better results. The study methodology followed leads to take measures based on: a) changing the type of fuel in the equipment that allows it, b) using the combination of less pollutant producing equipment with response capacity and c) considering the integration and incorporation of the pumped hydroelectric electric storage plant (PHES) "Chira-Soria" into Gran Canaria's electrical system. The different measures contribute to the improvement in the reduction of greenhouse gases (GHG) in a convincing way. Keywords: Isolated power system, Generation expansion planning, Energy transition, Insular electrical systems (IES), Energy policy, Canary Islands, Renewable energy, Pumped hydroelectric storage plant (PHES).

Coupling coordination between electricity and economy: China as an example

The benign coupling coordination between electricity (EL) and economy (EC) contributes to a better environment and sustainability. This study explores whether EL and EC can coordinate theoretically, how to evaluate their coordination, what the statuses are, and how to enhance coupling coordination levels (CCL). Specifically, we select the data from 2011 to 2020 of the 31 provincial regions of China, use information entropy weight and the technique for order preference by similarity to an ideal solution method, establish the theoretical coupling coordination mechanism and the evaluation index system to measure CCL temporally-spatially and propose policy implications based on prediction tendencies. We find that most regions' CCLs fluctuate temporally with mild upward trends, indicating the much more benign coupling coordination status; the spatial distributions are uneven with narrowing gaps. However, future CCL gaps may increase; therefore, differentiated policy implications are needed, such as encouraging balanced-coordination policies, innovating for higher-quality coordination, and cooperating for intelligence and wealth transfer. This study is conducive to theoretically describing the coupling coordination mechanism between EL and EC, providing new insights for CCL evaluation and the coordination practice for different regions.

234. EFFECTS OF TRANSCUTANEOUS ELECTRICAL STIMULATION SYSTEM ON HEARTBURN, REGURGITATION AND ESOPHAGEAL ACID EXPOSURE IN GERD PATIENTS

Abstract Background Chronic PPI treatment in GERD is associated with high failure rate and concerns regarding PPI's side effects. In a previously published proof of concept study, a non-pharmacological, non-invasive transcutaneous, electrical stimulation system, reduced esophageal acid exposure in GERD patients unresponsive to standard dose PPI. However, in that study, a symptomatic response to electrical stimulation was not assessed. Aim To determine the effect of a transcutaneous electrical stimulation system (TESS) on symptoms (heartburn and regurgitation) and the percentage of esophageal acid exposure time in GERD patients. Methods Patients suffering from heartburn and regurgitation were recruited into this multicenter study. The first phase of this study was a one week, run-in period, off-PPI's, during which, patients completed symptoms diaries and demographic questionnaires. Thereafter, all patients underwent upper endoscopy with subsequently wireless esophageal pH capsule placement (off PPI). Based on pH analysis in the first 24-hours, (day 0) only those with increased acid exposure time (percent total time pH <4 above 6%) continued to the next phase. During phase two of the study, patients were treated for two weeks with TESS and documented their symptoms. Primary end points included the reduction of baseline (pretreatment) number of heartburn and regurgitation episodes as well as 24-hour percent total time pH <4 and/or DeMeester score by at least 50%. Results 26 GERD patients (16 male, aged 47±15 years, mean BMI 25±3 kg/m2) completed the study. At baseline, mean number of daily heartburn and regurgitation events was 2.41±0.36 and 1.38±0.35, respectively. Following TESS, mean number of daily heartburn and regurgitation events dropped to 0.69±0.16 and 0.31±0.19, respectively (p=0.01). At baseline, mean percent total time pH < 4 was 11.8±0.9. Following TESS, mean percent total time pH < 4 dropped to 7.3±0.8, 7.8±1.0, 6.7±1.1 and 5.0±0.7 for day 1, 2, 3 and 4, respectively (p=0.01). At baseline, mean DeMeester score was 31.4±2.1. Following TESS, mean DeMeester score dropped to 20.1±2.0, 20.4±2.5, 17.3±2.6 and 14.3±2.0 for day 1, 2, 3 and 4, respectively (p=0.01). Conclusions TESS is effective in reducing both symptoms (heartburn and regurgitation) and esophageal acid exposure time in GERD patients.