Electric Energy Delivery Research Articles

A techno-economic framework for optimizing multi-area power dispatch in microgrids with tie-line constraints

Fuel-fired power plants are the primary electricity sources in Saudi Arabia. This investigation aims to reduce the overall costs and emissions of electricity production from thermal units operated by the Shuqaiq Water and Electricity Company. It also considers practical thermoelectric constraints, such as power losses, ramp-rate constraints, and environmental optimization functions, to align with the sustainability goals of Saudi Vision 2030. Optimizing electric energy delivery is crucial within an energy control center. The focus of this work is to develop an advanced computational technique that reduces reliance on fossil fuels and minimizes the production cost of electricity, while also considering environmental emissions as an optimization function. An examination was conducted through two distinct practical case studies with power demand of 850 MW—one involving renewable sources and the other without—to assess the effectiveness of the hybrid crow search and JAYA optimization algorithm in optimizing performance. This system includes a multi-area setup with limitations on the tie-line power flow constraints. Additionally, the study also involved RETScreen modelling to assess the practical financial, emission, and benchmark analysis of a proposed integrated solar plant. This analyses offers a thorough assessment of the facility’s performance and reliability in practical situations. This study serves as a motivating factor for energy operators, stakeholders, governmental organizations, and grid administrators to invest resources in environmentally-friendly initiatives. The simulation results showed that the proposed approach successfully reduced the electricity cost by 2.29% and 3.70% in hybrid energy networks while effectively handling the system constraints. In addition, the analysis revealed that the optimization algorithm effectively decreased toxic emissions from power plants while also supporting the sustainability objectives of United Nations SDG-7 and Saudi Vision 2030 through the successful integration of renewable sources.

Analysis of the pressure drop of sulfur hexafluoride (sf6) gas in a circuit breaker 150 KV Siemens 3AQ1EG

Abstract. The development of technology in the current era is very rapid and has an impact on increasing electrical energy which is a major need for large industries and households. One of the electrical energy delivery equipment in the transmission system is a PMT or High Connection Breaker. This PMT is a mechanical equipment equipped with sulfur hexafluoride (SF6) gas arc extinguishing media. The process of extinguishing the arc occurs due to contact due to work from the movement that causes the contact to cause an arc. This decrease in SF6 gas pressure greatly affects reliability when operating, because the arc extinguishing process is not perfect. This is determined by the age of the equipment and the number of operating breakers. The results showed that SF6 gas which is in accordance with the standard normal pressure of 6.4 bar with an ambient temperature of 34°C can minimize the occurrence of equipment damage because it is able to approach arc pressure with SF6 gas velocity of 58 cm/s.kA, with a contact gap of 3,61224. cm, while the PMT cannot be operated at a pressure of 5.2 bar with an ambient temperature of 34°C because the speed of SF6 gas is 82 cm/s.kA with a contact gap of 5.10696. It is concluded that the higher the pressure affects the speed and distance when extinguishing the arc. several factors that affect the decrease in SF6 gas pressure using the FMEA method based on the highest value of the Risk Priority Number (RPN) of 810. Keywords: fire arc, Breakdown, Voltage breaker, SF6 . gas pressure

Boosting electrochemical energy storage properties of SrGd2O4 through Yb3+ and Tm3+ rare earth ion doping

Electrochemical supercapacitors represent advanced energy storage devices that excel in the swift storage and delivery of electrical energy, effectively bridging the gap between conventional capacitors and batteries. The present work, aimed to investigate charge storage properties of SrGd2O4 and rare earth ions Yb3+ and Tm3+ doped in SrGd2O4. Both materials were prepared via simple sol-gel synthesis and characterized by XRD, XPS, and FE-SEM with EDS. Characterization confirmed the presence of Tm3+ and Yb3+ in the SrGd2O4 matrix with a uniform distribution of elements. The charge storage behavior of pure SrGd2O4 and SrGd2O4:Yb4Tm1 in various electrolytes was thoroughly explored. Large electrochemical potential windows were shown by both electrode materials in aqueous 6 M KOH (1.7 V), which is essential for supercapacitors to achieve high specific energy. Furthermore, SrGd2O4:Yb4Tm1 demonstrated a substantially more pronounced charge storage effect in 6 M KOH electrolyte, with almost double times higher specific capacitance values compared with an un-doped SrGd2O4 sample. The main impact on the electrochemical window had matrix SrGd2O4, while the main impact on specific capacitance had rear earth dopants (Yb3+ and Tm3+). Improved charge storage characteristics of SrGd2O4:Yb4Tm1 were also evident through a notable reduction in overall resistance observed in electrochemical impedance spectroscopy experiments. Concerning the two-electrode GCD measurements, the SrGd2O4:Yb4Tm1 electrode in 6 M KOH showed a specific capacitance of 143 F g−1, with the specific energy of 12.5 Wh kg−1 at 0.6 A g−1. These findings demonstrate the potential of rare earth ion doping in enhancing the energy storage properties of SrGd2O4, offering promising avenues for the development of high-performance supercapacitors.

Left ventricular assist devices: yesterday, today, and tomorrow.

The shortcomings of expense, power requirements, infection, durability, size, and blood trauma of current durable LVADs have been recognized for many years. The LVADs of tomorrow aspire to be fully implantable, durable, mitigate infectious risk, mimic the pulsatile nature of the native cardiac cycle, as well as minimize bleeding and thrombosis. Power draw, battery cycle lifespan and trans-cutaneous energy transmission remain barriers to completely implantable systems. Potential solutions include decreases in pump electrical draw, improving battery lifecycle technology and better trans-cutaneous energy transmission, potentially from Free-range Resonant Electrical Energy Delivery. In this review, we briefly discuss the history of LVADs and summarize the LVAD devices in the development pipeline seeking to address these issues.

Ecological Robustness-Oriented Grid Network Design for Resilience Against Multiple Hazards

Power systems are critical infrastructure for reliable and secure electric energy delivery. Incidents are increasing, as unexpected multiple hazards ranging from natural disasters to cyberattacks threaten the security and functionality of society. Inspired by resilient ecosystems, this paper presents a resilient network design approach with an ecological robustness (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ECO</sub> )-oriented optimization to improve power systems' ability to maintain a secure operating state throughout unknown hazards. The approach uses R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ECO</sub> , a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">surprisal</i> -based metric that captures key features of an ecosystem's resilient structure, as an objective to strategically design the electrical network. The approach enables solvability and practicality by introducing a stochastic-based candidate branch creation algorithm and a Taylor series expansion for relaxation of the R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ECO</sub> formulation. Finally, studies are conducted on the R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ECO</sub> -oriented approach using the IEEE 24 Bus RTS and the ACTIVSg200 systems. Results demonstrate improvement of the system's reliability under multiple hazards, network properties of robust structure and equally distributed power flows, and survivability against cascading failures. From the analysis, we observe that a more redundant network structure with equally distributed power flows benefits its resilience.

Mitochondrial network: electric cable and more

Mitochondria in a cell can unite and organize complex extended structures that extend over the entire cellular volume, ensuring a uniform supply of energy to cellular compartments with ATP synthesized in the mitochondria. In accordance with the chemiosmotic concept, the energy of oxidation of respiratory substrates is largely stored in the form of an electrical potential difference on the inner membrane of mitochondria. The theory of the functioning of extended mitochondrial structures as intracellular electrical wires suggests that mitochondria provide the fast delivery of electrical energy through the cellular volume, with following use of this energy for ATP synthesis, thereby speeding up the process of ATP delivery compared to the rather slow diffusion of ATP in the cell. The analytical review gives the history of the cable theory, solved and unsolved critical problems, the lability of the mitochondrial network and the role of oxidative stress in this process. In addition to the already proven functioning of extended mitochondrial structures as electrical cables, a few of additional functions are proposed, in particular, the hypothesis is put forward that mitochondrial networks provide a uniform distribution of redox potential throughout the cell, which can change in pathological conditions during fragmentation of the mitochondrial reticulum. A few of pathologies accompanied by a violation of the redox status and the participation of mitochondria in them are considered.

A survey on voltage stability indices for power system transmission and distribution systems

Voltage stability is a critical aspect of power system operation, ensuring the reliable and efficient delivery of electrical energy to consumers. Recently, voltage stability in the power system has received much attention. The primary cause of voltage instability is the lack of real and reactive power generation to cope with the continuous demand increment. Maintaining voltage stability while planning, controlling, and assessing the system’s security is a difficult task for power system engineers. From knowledge of past incidents, a lack of reactive power is identified as the primary cause of voltage instability, which may further lead to the total collapse of the system. The importance of voltage stability assessment is essential to maintain the integrity of power systems. It helps prevent voltage instability, which can lead to cascading failures and widespread outages. This paper uses various parameters, including load demand, generator capacity, and system impedance, to develop voltage stability indices (VSIs). The paper mainly focuses on the idea of VSIs that have been developed in order to monitor and control the criticality of the power system. The voltage stability indices for transmission and distributed systems, as well as their subclasses, are thoroughly reviewed in this study. Furthermore, traditional voltage stability methods, as well as various software tools for monitoring the voltage stability problems, are also discussed. In addition, the development of VSIs and its related concepts are clearly described in this paper. This comprehensive survey provides a decent groundwork for future work in this area, and assists professionals in selecting the optimal VSI for various applications. Moreover, it provides a concise overview of methods and the importance of voltage stability assessment in both transmission and distribution systems.

Optimal Integration of Distribution Network Reconfiguration and Conductor Selection in Power Distribution Systems via MILP

Power distribution systems (PDS) comprise essential electrical components and infrastructure that facilitate the delivery of electrical energy from a power transmission system to end users. Typically, the topology of distribution systems is radial, so that power goes from the substations to end users through main lines or feeders. However, the expansion of new feeders to accommodate new users and ever-growing energy demand have led to higher energy losses and deterioration of the voltage profile. To address these challenges, several solutions have been proposed, including the selection of optimal conductors, allocation of voltage regulators, utilization of capacitor banks, implementation of distributed generation, and optimal reconfiguration. Although reconfiguring the network is the most cost-effective approach, this solution might not be sufficient to completely minimize technical losses and improve system performance. This paper presents a novel approach that combines optimal distribution network reconfiguration (ODNR) with optimal conductor selection (OCS) to minimize power losses and enhance the voltage profiles of PDS. The key contribution lies in the integration of the ODNR and OCS into a single MILP problem, ensuring the attainment of globally optimal solutions. The proposed model was tested with benchmark 33-, 69-, and 85-bus test systems. The results allowed us to conclude that the combined effect of ODNR and OCS presents better results than when any of these approaches are applied either separately or sequentially.

Mitochondrial Network: Electric Cable and More.

Mitochondria in a cell can unite and organize complex, extended structures that occupy the entire cellular volume, providing an equal supply with energy in the form of ATP synthesized in mitochondria. In accordance with the chemiosmotic concept, the oxidation energy of respiratory substrates is largely stored in the form of an electrical potential difference on the inner membrane of mitochondria. The theory of the functioning of extended mitochondrial structures as intracellular electrical wires suggests that mitochondria provide the fastest delivery of electrical energy through the cellular volume, followed by the use of this energy for the synthesis of ATP, thereby accelerating the process of ATP delivery compared to the rather slow diffusion of ATP in the cell. This analytical review gives the history of the cable theory, lists unsolved critical problems, describes the restructuring of the mitochondrial network and the role of oxidative stress in this process. In addition to the already proven functioning of extended mitochondrial structures as electrical cables, a number of additional functions are proposed, in particular, the hypothesis is put forth that mitochondrial networks maintain the redox potential in the cellular volume, which may vary depending on the physiological state, as a result of changes in the three-dimensional organization of the mitochondrial network (fragmentation/fission-fusion). A number of pathologies accompanied by a violation of the redox status and the participation of mitochondria in them are considered.

Zinc/ Manganese Oxide Aqueous Electrolyte Batteries: Electrochemical Reaction Mechanisms Beyond Ion Insertion

The consistent delivery of clean electrical energy is a global challenge where the current electric grid infrastructure distributes electrical energy from the generation source to the end user. Widespread integration of inherently intermittent renewable energy sources such as wind and solar into the electric grid electrical energy storage into the electric grid demands incorporation of energy storage. Further, energy storage would enable control over when the electrical energy is used improving grid reliability and resiliency. Thus, stationary energy storage for the electric grid is a critical and timely application for batteries.Rechargeable aqueous zinc/ manganese oxide (Zn/MnO2) batteries are an appealing target for scalable stationary energy storage applications due to their low cost, safety, and environmentally benign components. Notably, manganese oxide is a versatile material where several polymorphs are viable cathode materials in aqueous zinc ion batteries. However, there is need for more complete understanding of the electrochemical reaction mechanisms, to continue to advance the system. This presentation will feature investigations of the reaction mechanisms with a focus on operando methods. X-ray diffraction, Mn K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements supported by ex situ transmission electron microscopy (TEM) will be presented. The findings provide a foundation for advancing the battery systems based on aqueous electrolyte zinc anode chemistries suitable for scalable stationary energy storage.

Self-Expandable Electrode Based on Chemically Polished Nickel-Titanium Alloy Wire for Treating Endoluminal Tumors Using Bipolar Irreversible Electroporation.

The application of irreversible electroporation (IRE) to endoluminal organs is being investigated; however, the current preclinical evidence and optimized electrodes are insufficient for clinical translation. Here, a novel self-expandable electrode (SE) made of chemically polished nickel-titanium (Ni-Ti) alloy wire for endoluminal IRE is developed in this study. Chemically polished heat-treated Ni-Ti alloy wires demonstrate increased electrical conductivity, reduced carbon and oxygen levels, and good mechanical and self-expanding properties. Bipolar IRE using chemically polished Ni-Ti wires successfully induces cancer cell death. IRE-treated potato tissue shows irreversibly and reversibly electroporated areas containing dead cells in an electrical strength-dependent manner. In vivo study using an optimized electric field strength demonstrates that endobiliary IRE using the SE evenly induces well-distributed mucosal injuries in the common bile duct (CBD) with the overexpression of the TUNEL, HSP70, and inflammatory cells without ductal perforation or stricture formation. This study demonstrates the basic concept of the endobiliary IRE procedure, which is technically feasible and safe in a porcine CBD as a novel therapeutic strategy for malignant biliary obstruction. The SE is a promising electrical energy delivery platform for effectively treating endoluminal organs.

Fabrication of tricarboxylate-neodymium metal organic frameworks and its nanocomposite with graphene oxide by hydrothermal synthesis for a symmetric supercapacitor electrode material

Efficient energy storage and delivery of electrical energy is necessary for the use of advanced electrode materials in super-capacitors, rendering their development pivotal. We employed simple and economical hydrothermal technique to synthesize Nd-metal organic frameworks (MOFs) and Nd-MOFs/GO composite and evaluated their suitability as electrode materials through comprehensive investigation. Characterizations of the synthesized materials were done by various techniques, including XRD, FTIR (using ATR method) and SEM. Based on the results obtained, it was found that the Nd-MOFs/GO composite-based electrode had a specific capacitance of 633.5 Fg−1 when tested at a current density of 0.3 Ag−1, which is significantly higher than that of Nd-MOFs electrode (11.3 Fg−1). Additionally, electrochemical impedance spectroscopy (EIS) analysis demonstrated the lowest equivalent series resistance (ESR) of 0.8 Ω for the Nd-MOFs/GO electrode. The Nd-MOFs/GO composite electrode exhibited a cyclic stability of 88.76 % after 4000 cycles and coulombic efficiency of 95.1%, when subjected to a current density of 3 Ag−1. Moreover XRD showed that the synthesized hybrid exhibited an improved crystallinity of the hexagonal phase. The FTIR analysis using ATR method confirmed the presence of organic ligands and functional groups in the synthesized materials. The results of our study indicate that the Nd-MOFs/GO hybrid nanocomposite-based electrode material holds potential as a highly efficient candidate for super-capacitor applications. The reported method of synthesizing MOFs provides an effective approach to fabricate new electrode materials with excellent electrochemical characteristics.

Impact of Quantum Movement Theory on Energy Policy

The Federal Energy Regulatory Commission (FERC) has been tasked with ensuring that the United States of America maintains a reliable electric grid that provides its citizens with affordable power and energy security. This responsibility of regulating electric energy delivery comes with the ability to charge and collect Interstate Commerce Tax. In this ability, is the separation of state and federal regulatory of electricity transactions, which is a contested topic in the U.S. Supreme Court. The reason for this is that FERC is trying to enforce Interstate Commerce Tax control over any equipment that poses the potential to generate electricity. They’re utilizing the 1880’s understanding of direct current (DC) electricity which moves through the “flow of electrons”, and therefore this gives them direct authority over all generators interconnected to the grid. Using the Quantum Movement Theory of Alternating Current established in 2023, this notion of a flow of electrons does not occur on the grid, and therefore restricts the jurisdiction and the taxing ability of FERC (Wade et al., 2023). This change would increase the implementation of Distributed Energy Resources (DERs) and save transmission operators, electric utilities, and ultimately consumers up to $500 million per year over the next several decades.

Optimization research on round-trip efficiency of a CHP system based on 10 kW-grade unitized regenerative fuel cell

The unitized regenerative fuel cell (URFC) integrates fuel cell and water electrolyzer into the same device, and the round-trip efficiency (RTE) is considered as an important criterion for evaluating its comprehensive performance. A model of URFC-based combined heat and power (CHP) system is developed, which takes into account the energy consumption of the components, and conducts orthogonal matrix analysis in three dimensions, including operating current density, temperature and pressure, to quantitatively evaluate the RTE of the CHP system based on URFC. The results show that the RTE of the system exceeds 75 % when the operating current density in FC mode lower than 0.6 A/cm2, and the operating current density in WE mode is between 1.4 A/cm2 and 3 A/cm2. The RTE of the system increases at lower FC temperatures, although the electrical output efficiency is lower. Compared to the working pressure of 1 atm in FC mode, the RTE of the system increases by 0.6 % at the working pressure of 3 atm. In addition, an adaptive optimization strategy is proposed, by adjusting the working current density in the two operating modes and controlling the temperature in the FC mode, which enables a proportional delivery of thermal and electrical energy according to demand and ensures high system efficiency.

An Advanced Artificial Neural Network Energy Management in Standalone PV Systems

With the ever-increasing prevalent power crisis and pollution of the environment, solar power, has attracted greater attention as a new and clean energy source. It provides an alternative solution for isolated sites with an unavailable grid connection. However, it is not without any drawbacks, mainly its intermittent nature, related primarily owing to its reliance on meteorological variables such as the temperature outside and the amount of sunlight. In effect, the PV systems that produced electrical energy could well display an electricity excess or deficit at the loads level, likely to result in system service discontinuity. In this respect, the present paper is designed to provide an intelligent management strategy to PV station owners with a dump load. It can involve serving two customers simultaneously according to the following scenarios: the PV production installation of the customer1 is greater than their required load; however, the customer2's neighboring station does not have enough power to cover its electrical load. This case brings electrical energy from the initial station to make up for the shortfall, and vice versa. Lithium-ion batteries step in the case when the essential electrical power cannot be delivered either by the local station or the neighboring one or to keep the accumulated power excess. If one of the stations (1 or 2) detects a power surplus and the batteries are completely charged, the generated power excess must be redirected to a secondary load, commonly known as the dump load. Relying on the artificial neural network controller, the suggested exchange control is used for two independent PV-battery stations with dump load. The MATLAB/Simulink attained simulation turns out to demonstrate the advanced controller’s noticeable performance and effectiveness in managing the standalone PV system’s operability in terms of continuous electrical energy delivery flow to the resistive load while reducing power waste and increasing the lithium-ion battery lifespan.

Connecting Smart Cities and Smart Villages: Providing Safe, Reliable Energy Delivery [In My View

As this issue of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IEEE Power &amp; Energy Magazine</i> addresses smart cities and smart villages, let us first address the connection between them. One lies in the history of electrical energy delivery. The first electrical systems were distributed, with electric power plants delivering power to local loads. Thomas Edison opened his first commercial electric power plant in 1882 on Pearl Street in New York, serving emerging city lighting. Within a decade, electric power had spread across the globe with many new applications. This expansion was accomplished by the construction of a reliable power pool or interconnected power system that focused on generating power from central generating stations.

The Importance of Power Generation Plants with Blackstart on Power System Restoration after Blackout

Güç sistemleri, elektrik enerjisinin kesintisiz bir şekilde tüketiciye ulaştırılmasını sağlayan ve birbiriyle koordineli çalıştırılan ekipmanların toplamı şeklinde ifade edilen kompleks yapılardır. Ancak bazı durumlarda güç sisteminde tam ya da kısmi olarak sistem çökmesi meydana gelebilmektedir. Bu sistem çökmesi bazen hemen giderilebilirken bazen de giderilmesi uzun sürmektedir. Uzun süren kesintiler sonrasında toplumsal yaşam, gündelik faaliyetler ve üretim faaliyetleri sekteye uğramakta; bu durum maddi olarak büyük bir kayba yol açmaktadır. Güç sisteminin tamamında meydana gelen bir sistem çökmesi sonrasında özenilerek hazırlanmış olan güç sistem restorasyonu planları hemen uygulanmaya başlanmalıdır. Güç sisteminin restorasyonunda kritik bir rol oynayan yeniden toparlanma özellikli güç üretim ünitelerinin konumu ve kapasitesi, sistem çökmesi sonrasında uygulanacak olan restorasyon stratejisine karar vermede büyük bir öneme sahiptir. Yapılan bu çalışmada güç sisteminin tam çökmesi sonrasında yeniden toparlanma özellikli güç üretim santrallerinin sistem restorasyonunda önemini anlamak için gerçek veriler kullanılarak simülasyon çalışması yapılmıştır. Yapılan çalışmada sistem çökmesi ve sistem restorasyonunun uygulama safhalarında güç üretim birimlerinin davranışları incelenmiştir. Güç sistem restorasyon planları hazırlanırken dikkat edilmesi gereken hususlar ile ilgili bilgi verilmiştir.

Implementation and Design of FREEDM System Differential Protection Method Based on Internet of Things

This paper introduces an enhancement of the protection and operation of the Future Renewable Electric Energy Delivery and Management (FREEDM) system. It uses the solid-state transformers to connect the residential A.C. and D.C. microgrids to the distribution system and fault isolation devices for faulty line isolation. In this paper, a current differential protection scheme has been proposed to detect faults in the FREEDM-based microgrid network. This method is based on the current measurement at the two-line terminals using phasor measurement units to ensure data synchronization and minimize the measuring error. Also, a communication scheme that is based on the Internet of things technology and Wi-Fi is constructed for data monitoring and interlinking between the relays, transducers, and the fault isolation devices in the two-terminals lines. A hypothetical FREEDM system has been used for the verification and testing of the proposed method. Different fault types at different locations and fault resistances have been applied to prove the effectiveness of the proposed protection method in detecting the fault condition. The performance of the proposed method is investigated using the security, dependability, and accuracy indices. A prototype of the FREEDM system is designed, implemented, and tested using the Proteus software simulator and in the laboratory. The results prove the efficiency of the proposed protection method in detecting and isolating the fault conditions in a fast, reliable, and accurate manner. Moreover, the protection scheme achieved high accuracy for all faults, equal to 98.825%.

A Nanoconfined Four-Enzyme Cascade Simultaneously Driven by Electrical and Chemical Energy, with Built-in Rapid, Confocal Recycling of NADP(H) and ATP.

The importance of energized nanoconfinement for facilitating the study and execution of enzyme cascades that feature multiple exchangeable cofactors is demonstrated by experiments with carboxylic acid reductase (CAR), an enzyme that requires both NADPH and ATP during a single catalytic cycle. Conversion of cinnamic acid to cinnamaldehyde by a package of four enzymes loaded into and trapped in the random nanopores of an indium tin oxide (ITO) electrode is driven and monitored through the simultaneous delivery of electrical and chemical energy. The electrical energy is transduced by ferredoxin NADP+ reductase, which undergoes rapid, direct electron exchange with ITO and regenerates NADP(H). The chemical energy provided by phosphoenolpyruvate, a fuel contained in the bulk solution, is cotransduced by adenylate kinase and pyruvate kinase, which efficiently convert the AMP product back into ATP that is required for the next cycle. The use of the two-kinase system allows the recycling process to be dissected to evaluate the separate roles of AMP removal and ATP supply during presteady-state and steady-state catalysis.

Mapping Heat Wave Hazard in Urban Areas: A Novel Multi-Criteria Decision Making Approach

Global population is experiencing more frequent, longer, and more severe heat waves due to global warming and urbanization. Episodic heat waves increase mortality and morbidity rates and demands for water and energy. Urban managers typically assess heat wave risk based on heat wave hazard, population exposure, and vulnerability, with a general assumption of spatial uniformity of heat wave hazard. We present a novel analysis that demonstrates an approach to determine the spatial distribution of a set of heat wave properties and hazard. The analysis is based on the Livneh dataset at a 1/16-degree resolution from 1950 to 2009 in Maricopa County, Arizona, USA. We then focused on neighborhoods with the most frequent, severe, earlier, and extended periods of heat wave occurrences. On average, the first heat wave occurs 40 days earlier in the eastern part of the county; the northeast part of this region experiences 12 days further extreme hot days and 30 days longer heat wave season than other regions of the area. Then, we applied a multi-criteria decision-making (MCDM) tool (TOPSIS) to evaluate the total hazard posed by heat wave components. We found that the northern and central parts of the metropolitan area are subject to the greatest heat wave hazard and that individual heat wave hazard components did not necessarily indicate heat hazard. This approach is intended to support local government planning for heat wave adaptation and mitigation strategies, where cooling centers, heat emergency water distribution networks, and electrical energy delivery can be targeted based on current and projected local heat wave characteristics.