Load frequency control of thermal system under deregulated environment using slime mould algorithm

This paper emphasizes the significance of PID controller parameters using a slime mould algorithm (SMA) to reduce load frequency control (LFC) issues in a thermal system in an open market scenario. The SMA is used to solve the parameterization of the PID controller, which was formulated as an optimization problem.The performance of the PID controller parameters improves the dynamic characteristics of the system as frequency in each area, and also deviations in tie line power after sudden load violation. In order to study the efficiency of the proposed method, the system was tested with different power transactions for a small load disturbance and the comparative results were presented. The optimal value of the controller parameters derived from SMA based PID controller is estimated using a finite nonlinear optimization using a performance index based method.

Energy Savings of Simultaneous Heating and Cooling System According to Indoor Set Temperature Changes in the Comfort Range

This study was conducted to derive the amount of energy savings when applying the method of making the load similar by changing the set temperature of the room in the building to which the simultaneous heating and cooling (SHC) system is applied. Energy savings were derived through theoretical analysis and comparisons through static simulations were performed to verify the proposed method. As a result, the energy savings are proportional to the energy limit that can be additionally input to the SHC and is proportional to the ratio of the coefficient of performance (COP) difference between the SHC and auxiliary heat source and the auxiliary heat source COP. That is, to increase the amount of energy savings, the maximum possible energy should be input for the SHC, or the SHC COP must be greater than the auxiliary heat source COP. In addition, comfort can be achieved stably by varying the set room temperature in a room with a small load. When a heat storage tank is installed or changing the indoor set temperature of both the hot and cold zones in real time by predicting the indoor load is possible, more energy can be saved.

Effect of Different Intensity Outdoor Tennis Training on Cardiac Load

Starting from the outdoor tennis competition, this paper studies the load characteristics of tennis competition through the experimental test of outdoor tennis players. This paper mainly adopts four research methods: literature, experimental test, mathematical statistics and logical analysis. This paper analyzes the load characteristics of outdoor tennis players in singles through experiments on the characteristics of competition time, the changes of center rate in the process of competition and the changes of creatine kinase, blood urea and urinary protein before and after competition. The results showed that the content of creatine kinase in blood increased significantly and the protein in urine increased significantly. This shows that outdoor tennis competition is more intense. The increase of blood urea after competition shows that there is a certain load in outdoor tennis competition, but the load is relatively small. The small load is mainly due to the short time of outdoor tennis competition, so the content of blood urea will not increase significantly.

Design and Stability Analysis of a proposed Microgrid for on Campus Diesel and Photovoltaic Power Sources

Pakistan is currently facing an energy crisis that is detrimental to its growth. Due to persistent load shedding by the National Grid throughout the country, the latest trend is tilting towards generating power at localized level through a mix of renewable and conventional energy sources. Such a mixture is referred to as Distributed Energy Resource (DER). Part of such a DER (i.e. solar energy) is free as naturally and mostly available in Pakistan having no degradation problem while providing benefit to the locality. The idea of using a Microgrid for our local power needs morphed accordingly. In this paper, a Microgrid design for our local campus i.e. University of Engineering & Technology, Peshawar, KPK is proposed. Our campus generators are not interconnected. Consequently, even while servicing small load periods, all of our campus’s diesel generators run at full capacity at the same time. Such a behavior is uneconomical, unacceptable and the generators run at low efficiency during islanding from the main utility grid. It is seen that behavior as such is endemic throughout Pakistan. Through design and analysis, it is proposed that if a Microgrid of such unconnected resources on campus is formed then during islanding, all generators and our Photovoltaic (PV) systems will economically and efficiently feed their common loads through load sharing. Synchronization, load flow analysis, short circuit analysis, harmonic analysis, transient stability, cost and reliability of our proposed Microgrid is analyzed using ETAP (Electrical Transient Analyzer Program) in this paper.

Mathematical Modeling Reveals Quantitative Properties of KEAP1-NRF2 Signaling

In response to oxidative and electrophilic stresses, cells launch an NRF2-mediated transcriptional antioxidant program. The activation of NRF2 depends on a redox sensor, KEAP1, which acts as an E3-ligase adaptor to promote the ubiquitination and degradation of NRF2. While a great deal has been learned about the molecular details of KEAP1, NRF2, and their interactions, the quantitative aspects of signal transfer conveyed by this redox duo are still largely unexplored. In the present study, we examined the signaling properties including response time, half-life, maximal activation, and response steepness (ultrasensitivity) of NRF2, through a suite of mathematical models. The models describe, with increasing complexity, the reversible binding of KEAP1 dimer and NRF2 via the ETGE and DLG motifs, NRF2 production, KEAP1-dependent and independent NRF2 degradation, and perturbations by different classes of NRF2 activators. Our simulations revealed that at the basal condition, NRF2 molecules are largely sequestered by KEAP1, with the KEAP1-NRF2 complex comparably distributed in either an ETGE-bound only (open) state or an ETGE and DLG dual-bound (closed) state, corresponding to the unlatched and latched configurations of the conceptual hinge-latch model. With two-step ETGE binding, the open and closed states operate in cycle mode at the basal condition and transition to equilibrium mode at stressed conditions. Class I-V, electrophilic NRF2 activators, which modify redox-sensing cysteine residues of KEAP1, shift the balance to a closed state that is unable to degrade NRF2 effectively. Total NRF2 has to accumulate to a level that nearly saturates existing KEAP1 to make sufficient free NRF2, therefore introducing a signaling delay. At the juncture of KEAP1 saturation, ultrasensitive NRF2 activation, i.e., a steep rise in the free NRF2 level, can occur through two simultaneous mechanisms, zero-order degradation mediated by DLG binding and protein sequestration (molecular titration) mediated by ETGE binding. These response characteristics of class I-V activators do not require disruption of DLG binding to unlatch the KEAP1-NRF2 complex. In comparison, class VI NRF2 activators, which directly compete with NRF2 for KEAP1 binding, can unlatch or even unhinge the KEAP1-NRF2 complex. This causes a shift to the open state of KEAP1-NRF2 complex and ultimately its complete dissociation, resulting in a fast release of free NRF2 followed by stabilization. Although class VI activators may induce free NRF2 to higher levels, ultrasensitivity is lost due to lower free KEAP1 and thus its NRF2-sequestering effect. Stress-induced NRF2 nuclear accumulation is enhanced when basal nuclear NRF2 turnover constitutes a small load to NRF2 production. Our simulation further demonstrated that optimal abundances of cytosolic and nuclear KEAP1 exist to maximize ultrasensitivity. In summary, by simulating the dual role of KEAP1 in repressing NRF2, i.e., sequestration and promoting degradation, our mathematical modeling provides key novel quantitative insights into the signaling properties of the crucial KEAP1-NRF2 module of the cellular antioxidant response pathway.

Analisis Tren Konsumsi Energi Listrik pada Penyulang Singkarak

Electrical energy use is an interesting topic because it is related to the operational planning of the distribution system, maintenance of medium voltage networks, and prediction of electricity consumption, especially in the short term. Trends are created based on historical data represented in the load curves. This research aims to determine the characteristics of the load by making load groups according to the type of day and calculate the load factor based on secondary data from PT. PLN (Persero) Borang substation. The research uses comparative techniques in the load groups and calculates the load factor which is the benchmark for generation capacity. The results of the study showed that the load trendon Singkarak feeders in overall is the same on weekdays as on weekends, namely that minimum load occurs in the morning at 07.00, the load starts to increase but is not significant in relation to the activities of the population after 08.00-16.00. The load trend increases significantly from 16.00 to the peak load that occurs at 19.00-21.00 and after that, the load goes down to the minimum load. The trend for higher than average peak loads on Mondays is more common and weekend loads on Saturdays and Sundays only relatively small load fluctuationsoccur.. The load group for religious holidays and national holidays received good load factor scores, with a relatively small range of loads throughout the day.

Short-Term Load Forecasting Using an Attended Sequential Encoder-Stacked Decoder Model with Online Training

The paper presents a new approach for the prediction of load active power 24 h ahead using an attended sequential encoder and stacked decoder model with Long Short-Term Memory cells. The load data are owned by the New York Independent System Operator (NYISO) and is dated from the years 2014–2017. Due to dynamics in the load patterns, multiple short pieces of training on pre-filtered data are executed in combination with the transfer learning concept. The evaluation is done by direct comparison with the results of the NYISO forecast and additionally under consideration of several benchmark methods. The results in terms of the Mean Absolute Percentage Error range from 1.5% for the highly loaded New York City zone to 3% for the Mohawk Valley zone with rather small load consumption. The execution time of a day ahead forecast including the training on a personal computer without GPU accounts to 10 s on average.

Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM)

The response of the quartz crystal microbalance (QCM, also: QCM-D for “QCM with Dissipation monitoring”) to loading with a diverse set of samples is reviewed in a consistent frame. After a brief introduction to the advanced QCMs, the governing equation (the small-load approximation) is derived. Planar films and adsorbates are modeled based on the acoustic multilayer formalism. In liquid environments, viscoelastic spectroscopy and high-frequency rheology are possible, even on layers with a thickness in the monolayer range. For particulate samples, the contact stiffness can be derived. Because the stress at the contact is large, the force is not always proportional to the displacement. Nonlinear effects are observed, leading to a dependence of the resonance frequency and the resonance bandwidth on the amplitude of oscillation. Partial slip, in particular, can be studied in detail. Advanced topics include structured samples and the extension of the small-load approximation to its tensorial version.

Effect of Underload Cycles on Oxide-Induced Crack Closure Development in Cr-Mo Low-Alloy Steel

Underload cycles with small load amplitudes below the fatigue crack growth threshold are dominantly considered as insignificant cycles without any influence on fatigue lifespan of engineering structural components. However, this paper shows that in some cases these underload cycles can retard the consequent crack propagation quite significantly. This phenomenon is a consequence of oxide-induced crack closure development during cyclic loading below the threshold. The experimentally described effect of fatigue crack growth retardation was supported by measurement of the width and the thickness of the oxide debris layer using the EDS technique and localized FIB cuts, respectively. Both the retardation effect and the amount of oxide debris were larger for higher number and larger amplitudes of the applied underload cycles. Crack closure measurement revealed a gradual increase of the closure level during underload cycling. Specimens tested in low air humidity, as well as specimens left with the crack open for the same time as that needed for application of the underload cycles, revealed no retardation effect. The results can improve our understanding of environmental effects on fatigue crack propagation and understanding the differences between the results of laboratory testing and the fatigue lives of components in service.