Transmission Expansion Planning : computational challenges toward real-size networks

The importance of the transmission network for supplying electricity demand is undeniable, and Transmission Expansion Planning (TEP) studies is key for a reliable power system. Due to increasing sources of uncertainty such as more intermittent energy resources, mobile and controllable demands, and fast technology improvements for PVs and energy storage devices, the need for using systematic ways for solving this complex problem is increased. One of the main barriers for deploying optimization-based TEP studies is computationally intractability, which is the main motivation for this research. The aim of this work is to investigate the computational challenges associated with systematic TEP studies for large-scale problems, and develop algorithms to improve computational performance. In the first step, we investigate the impact of adding security constraints (as NERC standard requirement) into TEP optimization problem, and develop the Variable Contingency List (VCL) algorithm to pre-screen security constraints to only add those that may affect the feasible region. It significantly decreases the size of the problem compared to considering all security constraints. Then, we evaluate the impact of the size of candidate lines list (number of binary variables) on TEP, and developed a heuristic algorithm to decrease the size of this list. In the next step, we integrate uncertainties into the TEP optimization problem and formulate the problem as a two-stage stochastic program. Adding uncertainties increases the size of the problem significantly. It leads us to develop a three-level filter that introduces important scenario identification index (ISII) and similar scenario elimination (SSE) technique to decrease the number of security constraints in stochastic TEP in a systematic and tractable way. We then investigate the scalability of the stochastic TEP formulation. We develop a configurable decomposition framework that allows us to decompose the original problem into subproblems that can be solved independently and in parallel. This framework can benefit from using both progressive hedging (PH) and Benders decomposition (BD) algorithms to decompose and parallelize a large-scale problem both vertically and horizontally. We have also developed a bundling algorithm that improves the performance of PH algorithm and the overall performance of the framework. We have implemented our work on a reduced ERCOT network with more than 3000 buses to demonstrate the practicality of the proposed method in this work for large-scale problems.Electrical and Computer Engineerin

Investigating the Importance and Goals of Economic Fish Farming in Faryab Province

This research is about the importance and goals of fish farming in Faryab province, considering the world\u27s population which is constantly increasing and its growth will not stop at any time, there is no doubt that the world\u27s current food industry will not meet the needs and humans must Think about food sources for new protein sources. Fish is one of the most important resources for humans, especially food sources: major fishermen and people who catch fish only for a living catch these animals from the wild. The importance of this current research on the importance of fish farming in our Faryab, regardless of the fact that it provides part of the food rich in protein needed by our country. It is an important source of employment for unemployed people in the rural areas of Faryab province. On the other hand, Faryab Province, with its diverse climatic conditions, and abundant natural facilities, has a good background for breeding activities of freshwater and warm water fish. It can be seen that different districts of Faryab Province have a blessed sea that has prepared a colorful table for thousands of living creatures. The main purpose of conducting research is to obtain information about the importance and objectives of fish farming in Faryab province, and with the increase in population, the demand for aquatic products, especially fish meat, is increasing. At present, fish meat food is promoted in many restaurants in Faryab province and fish meat has a good market in this province, so in this regard, every day tens of kilos of high-quality raw fish enter Faryab province from the provinces and districts of Afghanistan. This is proof of having a good domestic market for fish meat in Faryab province. Fish resources are renewable resources. A large number of people in developed and developing countries are busy working in this sector. Fish breeding and hunting are one of the most beneficial jobs for the people of the world, Afghanistan, and especially the people of Faryab province. Fish meat provides approximately 14 percent of the animal protein needed by the world\u27s population. In a number of developing countries, fish is a supplementary food component of the people\u27s diet. Fish farming and fishing are a source of employment and foreign currency income in developed and developing countries. The necessary information about the background of this research was collected from books, articles, and authentic scientific journals, and in the findings section, the necessary information was collected using a questionnaire, and the results after analysis were included in the findings section

Adaptive Finite-Element-Ausgleichsformulierungen für parabolische Anfangs-Randwertaufgaben

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Max-Min Fairness Based on Cooperative-NOMA Clustering for Ultra-Reliable and Low-Latency Communications

In this paper, the performance of a cooperative relaying technique in a non-orthogonal multiple access (NOMA) system, briefly named cooperative NOMA (C-NOMA), is considered in short packet communications with finite blocklength (FBL) codes. We examine the performance of a decode-and-forward (DF) relaying along with selection combining (SC) and maximum ratio combining (MRC) strategies at the receiver. Our goal is user clustering based on C-NOMA to maximize fair throughput in a DL-NOMA scenario. In each cluster, the user with a stronger channel (strong user) acts as a relay for the other one (weak user), and optimal power and blocklength are allocated to achieve max-min throughput.Comment: 11 pages, 6 figures, This paper has been submitted for IEEE systems journa

Hierarchical Flexibility Offering Strategy for Integrated Hybrid Resources in Real-time Energy Markets

This paper proposes a hierarchical model for determining the energy flexibility offering strategy of integrated hybrid resources (IHRs) in power distribution systems to participate in real-time energy markets. The proposed model utilizes the scalability, fast response time, and uncertainty observation of deep reinforcement learning (DRL) to overcome the scalability issue of operating numerous flexible resources and deliverability of energy flexibility to the real-time markets in the presence of the network constraints. To that end, the power distribution system is divided into multiple IHRs, where different types of flexible loads, energy storage systems, and solar plants with controllable inverters are operated through local IHR controllers, trained by deep deterministic policy gradient (DDPG) algorithm. Active power request and reactive power capacity of IHRs are then transmitted to a central flexibility controller, where a quadratic optimization model ensures the deliverability of the energy flexibility to the real-time energy market by satisfying the distribution network constraints. The proposed model is implemented on the 123-bus test power distribution system, demonstrating the capability of DRL-based hierarchical model for scalable operation of IHRs in order to offer deliverable energy flexibility to the real-time energy market

Isolamento de Cryptococcus neoformans de excrementos de andorinhas (Hirundo rustica) do Irã

Cryptococcus neoformans is an encapsulated yeast that can cause cryptococcosis, a life-threatening infection that mainly occurs in immunocompromised patients. The major environmental sources of C. neoformans have been shown to be soil contaminated with avian droppings. In the present study, we evaluated the isolation of C. neoformans from swallow (Hirundo rustica) excreta in two northern cities of Iran. Ninety-seven swallow droppings were evaluated and 498 yeast-like colonies were isolated and identified as Rhodotorula spp. (62.8%), Candida spp. (28.5%)and C. neoformans (8.7%). Cryptococcus neoformans was isolated from 5/97 (5.2%) of collected samples. Min-Max colony forming units (CFU) per one gram for the positive samples were 3-10 C. neoformans colonies. The total mean CFU per one gram for the positive samples was 4.8. The results of this study demonstrate that excreta of swallow may harbor different species of potentially pathogenic yeasts, mainly C. neoformans, and may be capable of disseminating these fungi in the environment.Cryptococcus neoformans é levedura encapsulada que pode causar criptococose, infecção potencialmente mortal que ocorre principalmente em pacientes imunocomprometidos. As principais fontes ambientais de C. neoformans são o solo contaminado com fezes de aves. No presente estudo, avaliamos o isolamento de C. neoformans de excreta de andorinhas (Hirundo rustica) em duas cidades do norte do Irã. Noventa e sete amostras de fezes de andorinhas foram avaliadas e 498 colonias semelhantes à levedura foram isoladas e identificadas como Rhodotorula spp. (62,8%), Candida spp. (28,5%), C. neoformans (8,7%). Cryptococcus neoformans foi isolado a partir de 5/97 (5,2%) das amostras coletadas. Unidades Min-Max formadoras de colonias (CFU) por 1 grama das amostras positivas foram 3-10 coloniasde C. neoformans. A média total de CFU por 1 grama das amostras positivas foi de 4,8. Os resultados deste estudo demonstram que excrementos de andorinhas podem abrigar diferentes espécies de leveduras potencialmente patógenas, principalmente C. neoformans, e podem ser capazes de disseminar estes fungos no meio ambiente

Technical Feasibility of Recycling Waste Cooking Oils (WCO) Produced in Qom to Biodiesel

Background: The aim of this research was to study the technical feasibility of recycling waste cooking oils (WCO) produced in Qom to biodiesel. Methods: This cross-sectional study was performed in Qom in the first half of 2013. In this study, 147 domestic, commercial, and industrial sources producing WCO were identified, selected, and asked to collect and deliver the WCO produced by them within a week. The samples obtained from the sources were mixed separately at a ratio of one to one, and finally, a WCO sample was obtained from each source. Then, some characteristics of samples such as chemical profiles were analyzed and the esterification and transesterification process were used to convert WCO into biodiesel. Finally, some of the technical characteristics of produced biodiesel such as flash point, viscosity, density, moisture, and acidic number were determined and compared with the standard. Results: In terms of basic properties, domestic WCO had the best quality for conversion to biodiesel. Also, in terms of viscosity, density, acidic number and flash point, biodiesel produced from domestic WCO had more favorable conditions. In terms of the percentage of humidity, biodiesel produced from industrial WCO was the best one. Conclusion: WCO produced from domestic and commercial sources has the potential to be converted into biodiesel with standard features but WCO produced from industrial sources due to their very poor quality needs more pre-treatment processes

Drag coefficient of a rising bubble in a shear-thinning fluid using the power-law scheme coupled with a Cahn-Hilliard equation with a variable mobility: A lattice Boltzmann study and comparison with experiment

This study aims to investigate the behavior of multicomponent fluid flows consisting of Newtonian and non-Newtonian components, especially terminal velocity of a rising bubble in a power-law fluid. A recent lattice Boltzmann (LB) model is extended using power-law scheme to be able to simulate both Newtonian and non-Newtonian fluid flows at high density and viscosity ratios. Also, a variable mobility is introduced in this study to minimize the unphysical error around small bubbles in the domain. A three-component fluid flow system is examined using a constant and variable mobility. It is shown that each component has more stability using variable mobility while constant mobility causes interface dissipation, leading to mass loss gradually. In addition, two test cases including power-law fluid flows driven between two parallel plates are conducted to show the accuracy and capability of the model. To find a grid-independent computational domain, a grid independency test is carried out to show that a 200*400 domain size is suitable for our computations. Then, terminal velocity of a rising bubble is compared to an existing correlation in the literature, indicating that the results are in good agreement with existing study so that average relative error in six different cases is 5.66 %. Also, the simulated examples show good conformity to experimental results over a range of the Reynolds and Eotvos numbers

The effect of melatonin on in vitro maturation fertilization and early embryo development of mouse oocytes and expression of HMGB1 gene in blastocysts

Antioxidants are commonly used for maturation, fertilization and early development of embryos. Melatonin as an antioxidant have been recently proven to be useful for the assisted reproductive technology. In the present study, we evaluated the roles of melatonin in the in vitro maturation, fertilization, development and also the gene expression of high mobility group box-1 (HMGB1) in the blastocysts. The immature oocytes of BDF1 mice were transferred to the media containing different doses of melatonin (10-6, 10-9, 10-12 M). The blastocysts that developed under in vitro fertilizationfrom each group were stained to determine the cell number of embryos and analyzed to determine the expression level of HMGB1 by real-time PCR. The most effective doses of melatonin for maturation of oocytes were 10-6 and 10-12M (P<0.05). Fertilization rate, early development and the cell number of blastocysts were significantly higher in the group that treated with 10-12 M of melatonin comparing to the other groups. The HMGB1 expression decreased in groups that treated with 10-6M and 10-9M of melatonin and increased in the group that treated with 10-12 M of melatonin, but did not show a significant difference (p˃0.05). From the results, it may be concluded that the melatonin could be effective when the embryos undergo maturation, fertilization and early developmental processes. The HMGB1 expression, as a marker of early development in mice embryos, increased in the groups that treated with low doses of melatonin