100 research outputs found

    A Scenario Approach for Operational Planning with Deep Renewables in Power Systems

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    This work is both enabled by and motivated by the development of new resources and technologies into the power system market operation practice. On one hand, penetration level of uncertain generation resources is constantly increasing and on the other hand, retirement of some of the conventional energy resources like coal power plants makes market operations an attractive topic for both theoretical and state-of-the-art research. In addition, as generation uncertainty increases, it impacts the true cost of energy and causes it to be volatile and on average higher. This work targets flexibility enhancement to the grid to potentially eliminate the impact of uncertainty. Two different viewpoints in two different markets for electricity is targeted. This dissertation looks at the real-time market generation adequacy from the Independent System Operator’s point of view, and the day-ahead scheduling of energy and reserve procurement from the market participant’s point of view. At the real time scale, the emphasis is on developing fast and reliable optimization techniques in solving look-ahead security constrained economic dispatch. The idea is when forecast accuracy gets sharper closer to the real-time and slower power plants retiring in recent years, market participants will spend more and more attention to the real-time market in comparison to the day ahead operation in terms of the energy market. To address it, a data-driven model with rigorous bounds on the risk is proposed. In particular, we formulate the Look-Ahead Security Constrained Economic Dispatch (LAED) problem using the scenario approach techniques. This approach takes historical sample data as input and guarantees a tunable probability of violating the constraints according to the input data size. Scalability of the approach to real power systems was tested on a 2000 bus synthetic grid. The performance of the solution was compared against state-of-the-art deterministic approach as well as a robust approach. Although the real-time market is primarily for energy trading, the day-ahead market is the market for ancillary service trading. In this dissertation, at the day-ahead scale, the focus is on providing ancillary service to the grid by controlling the consumption of millions of privately owned ii pool pumps in the US, while benefiting from energy arbitrage. A conceptual framework, a capacity assessment method, and an operational planning formulation to aggregate flexible loads such as inground swimming pool pumps for a reliable provision of spinning reserve is introduced. Enabled by the Internet of Things (IoT) technologies, many household loads offer tremendous opportunities for aggregated demand response at wholesale level markets. The spinning reserve market is one that fits well in the context of swimming pool pumps in many regions of the U.S. and around the world (e.g. Texas, California, Florida). This work offers rigorous treatment of the collective reliability of many pool pumps as firm generation capacity. Based on the reliability assessment, optimal scheduling of pool pumps is formulated and solved using the deterministic approach and the scenario approach. The case study is performed using empirical data from Electric Reliability Council of Texas (ERCOT). Cost-benefit analysis based on a city suggests the potential business viability of the proposed framework

    A Scenario Approach for Operational Planning with Deep Renewables in Power Systems

    Get PDF
    This work is both enabled by and motivated by the development of new resources and technologies into the power system market operation practice. On one hand, penetration level of uncertain generation resources is constantly increasing and on the other hand, retirement of some of the conventional energy resources like coal power plants makes market operations an attractive topic for both theoretical and state-of-the-art research. In addition, as generation uncertainty increases, it impacts the true cost of energy and causes it to be volatile and on average higher. This work targets flexibility enhancement to the grid to potentially eliminate the impact of uncertainty. Two different viewpoints in two different markets for electricity is targeted. This dissertation looks at the real-time market generation adequacy from the Independent System Operator’s point of view, and the day-ahead scheduling of energy and reserve procurement from the market participant’s point of view. At the real time scale, the emphasis is on developing fast and reliable optimization techniques in solving look-ahead security constrained economic dispatch. The idea is when forecast accuracy gets sharper closer to the real-time and slower power plants retiring in recent years, market participants will spend more and more attention to the real-time market in comparison to the day ahead operation in terms of the energy market. To address it, a data-driven model with rigorous bounds on the risk is proposed. In particular, we formulate the Look-Ahead Security Constrained Economic Dispatch (LAED) problem using the scenario approach techniques. This approach takes historical sample data as input and guarantees a tunable probability of violating the constraints according to the input data size. Scalability of the approach to real power systems was tested on a 2000 bus synthetic grid. The performance of the solution was compared against state-of-the-art deterministic approach as well as a robust approach. Although the real-time market is primarily for energy trading, the day-ahead market is the market for ancillary service trading. In this dissertation, at the day-ahead scale, the focus is on providing ancillary service to the grid by controlling the consumption of millions of privately owned ii pool pumps in the US, while benefiting from energy arbitrage. A conceptual framework, a capacity assessment method, and an operational planning formulation to aggregate flexible loads such as inground swimming pool pumps for a reliable provision of spinning reserve is introduced. Enabled by the Internet of Things (IoT) technologies, many household loads offer tremendous opportunities for aggregated demand response at wholesale level markets. The spinning reserve market is one that fits well in the context of swimming pool pumps in many regions of the U.S. and around the world (e.g. Texas, California, Florida). This work offers rigorous treatment of the collective reliability of many pool pumps as firm generation capacity. Based on the reliability assessment, optimal scheduling of pool pumps is formulated and solved using the deterministic approach and the scenario approach. The case study is performed using empirical data from Electric Reliability Council of Texas (ERCOT). Cost-benefit analysis based on a city suggests the potential business viability of the proposed framework

    Reserves from Controllable Swimming Pool Pumps: Reliability Assessment and Operational Planning

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    This paper introduces a conceptual framework, a capacity assessment method, and a data-driven optimization algorithm to aggregate flexible loads such as in-ground swimming pool pumps for reliable provision of spinning reserves. Enabled by Internet of Things (IoT) technologies, many household loads offer tremendous opportunities for aggregated demand response at wholesale level markets. The spinning reserve market is one that fits well in the context of swimming pool pumps in many regions of the U.S. and around the world (e.g. Texas, California, Florida). This paper offers rigorous treatment of the collective reliability of many pool pumps as firm generation capacity. Based on the reliability assessment, an optimal scheduling of pool pumps is formulated and solved using scenario-based approach. The case study is performed using empirical data from Electric Reliability Council of Texas (ERCOT). Cost-benefit analysis based on a city suggests the potential business viability of the proposed framework

    Alkaloids: The Potential of Their Antimicrobial Activities of Medicinal Plants

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    Given the potential adverse effects of chemical drugs, utilizing natural products with diverse therapeutic and antimicrobial compounds is advisable. Countries can use indigenous flora from their regions in vegetation for medicinal purposes. Several nations exhibit distinctive indigenous flora owing to their geographic positioning and climatic conditions. These plants have been the subject of our research, which has explored their antimicrobial properties against fungi, parasites, bacteria, and viruses. Studies have investigated the therapeutic and antimicrobial effects of plants and their bioactive compounds, such as alkaloids, flavonoids, and terpenoids. Among them are alkaloids, a diverse class of naturally occurring chemicals, such as tropanes, terpenoids, and steroids. Some of these medicinal plants have been found to possess antioxidant and anti-inflammatory properties in addition to their antimicrobial effects. This chapter explores the antimicrobial potential of alkaloids found in medicinal plants

    Distribution and Prevalence Potato virus Y Isolates Obtained from Potatoes Grown in the Iran by RT-PCR

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    To survey the distribution and prevalence of potato virus Y (PVY) strains in north western Iran, 381 symptomatic infected samples of the main potatoes grown in the said region were collected from the fields between (Hall et al., 1998) 2007 and 2008. The collected samples were first tested for PVY infection via a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) technique. Of the total number of collected samples, 79 (20.73%) tested positive for PVY infection. The highest level of PVY infection was observed in the district of Gilak-Abad in Sarab County, whereas the lowest infection was observed in the district of Oughan in the suburbs of Sarab city. The RT-PCR detection of PVY strains by using specific primers resulted in the amplification of DNA fragments specific to the PVY strains NTN, C, O, and N at 725, 1553, 352, and 616 bp, respectively. The highest strain diversity of PVY was detected in the district of Shirehjin in Sarab city and the lowest in the district of Ghaleh Jugh in Bostan-Abad city. Both single and multiple infection types of the PVY stains were observed in the region. Of the 79 PVY-infected samples, 77.21% were infected with strain O, 62.02% with strain C, 39.24% with strain N, and 8.86% with strain NTN. The highest level of multiple infections was observed in the combinations of the strains C+O (27.84%) and the triple strains O+N+C (15.18%). This paper is the first to report the detection of the PVY strain NTN in Iran. Keywords: RT-PCR, Molecular diagnosis, Potato, ELISA, Potato Virus Y (PVY

    The Relationship between Zinc Deficiency and Febrile Convulsion in Isfahan,Iran

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    Objective  Febrile convulsion (FC) is a common cause of seizure in young children, with an excellent prognosis. In addition to genetic predisposition and infections,FCs are generally thought to be induced by metabolic and elemental changes during fever such as Zinc (Zn) deficiency. Regarding the high prevalence of febrile convulsions and the role of Zn deficiency, we investigated the role of Zn in FC patients in Isfahan, Iran.  Materials and Methods  In a controlled cross sectional study, 90 patients aged 9 months to 5 years were studied in a period of 12 months. They were assigned to three groups. Thirty patients were included in the Febrile Seizure group, thirty febrile children without convulsion or previous history of convulsion were included in the febrile group and thirty afebrile healthy ones were enrolled as controls. Venous blood was obtained and Zn concentration in serum was measured using Graphite Furnance Atomic Absorbance Spectrophotometering (GF-AAS).  Results  Patients and the control groups had no difference in either mean age or sex distribution. No significant relationship was observed between serum Zn level and age or sex among patients in the FC group and two other control groups.   Conclusion  Our findings showed that Zinc level was significantly lower in the febrile seizure group compared to two other groups. We tried to categorize various conditions in a more practical form. Also, Zinc is in close relationship with socioeconomic level of the individuals which was well considered in the current survey.  Keywords: Zinc; Zinc deficiency; Febrile Convulsion

    Knockdown of BACE1-AS Nonprotein-Coding Transcript Modulates Beta-Amyloid-Related Hippocampal Neurogenesis

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    Background. Alzheimer's disease (AD) is a devastating neurological disorder and the main cause of dementia in the elderly population worldwide. Adult neurogenesis appears to be upregulated very early in AD pathogenesis in response to some specific aggregates of beta-amyloid (Aβ) peptides, exhausting the neuronal stem cell pools in the brain. Previously, we characterized a conserved nonprotein-coding antisense transcript for β-secretase-1 (BACE1), a critical enzyme in AD pathophysiology. We showed that the BACE1-antisense transcript (BACE1-AS) is markedly upregulated in brain samples from AD patients and promotes the stability of the (sense) BACE1 transcript. In the current paper, we examine the relationship between BACE1, BACE1-AS, adult neurogenesis markers, and amyloid plaque formation in amyloid precursor protein (APP) transgenic mice (Tg-19959) of various ages. Results. Consistent with previous publications in other APP overexpressing mouse models, we found adult neurogenesis markers to be noticeably upregulated in Tg-19959 mice very early in the development of the disease. Knockdown of either one of BACE1 or BACE1-AS transcripts by continuous infusion of locked nucleic acid- (LNA-) modified siRNAs into the third ventricle over the period of two weeks caused concordant downregulation of both transcripts in Tg-19959 mice. Downregulation of BACE1 mRNA was followed by reduction of BACE1 protein and insoluble Aβ. Modulation of BACE1 and BACE1-AS transcripts also altered oligomeric Aβ aggregation pattern, which was in turn associated with an increase in neurogenesis markers at the RNA and protein level. Conclusion. We found alterations in the RNA and protein concentrations of several adult neurogenesis markers, as well as non-protein-coding BACE1-AS transcripts, in parallel with the course of β-amyloid synthesis and aggregation in the brain of Tg15999 mice. In addition, by knocking down BACE1 or BACE1-AS (thereby reducing Aβ production and plaque deposition), we were able to modulate expression of these neurogenesis markers. Our findings suggest a distortion of adult neurogenesis that is associated with Aβ production very early in amyloid pathogenesis. We believe that these alterations, at the molecular level, could prove useful as novel therapeutic targets and/or as early biomarkers of AD

    Experimental and Numerical Study of Pile-to-Pile Interaction Factor in Sandy Soil

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    AbstractIn structures to support large vertical and horizontal loads, piles are usually used in the form of closely spaced group. The piles in a group are not only affected by their individual loads transmitted from the pile cap, but also by additional loads transferred through the soil from the interference of neighboring piles. This group interaction influences the group stiffness, load-transfer mechanism and group settlement. In order to predict the response characteristics of pile groups, the interaction factors calculated using Mindlin's solution based on the theory of elasticity has been widely applied. The pile-to-pile interaction factor is defined as the ratio of displacements or rotations of an unloaded receiver pile to those of neighboring loaded source pile due to soil deformation. In this paper, a series of centrifuge model tests were carried out to examine the effect of soil relative density and pile spacing and pile tip condition on the interaction factor between two adjacent piles. Based on the results, soil relative density has a significant effect on the interaction between piles and thus it must be considered in the calculation of interaction factor. For this purpose, a correction to the Randolph and Wroth equation based on the test results was proposed in which the effect of soil relative density is contemplated. With an increase in the pile spacing, the value of interaction factor for all cases decreased. Compared to the effect of pile shaft, pile tip condition has a little effect on the interaction factor. The obtained results were also compared with those from a three-dimensional finite element analysis and a good agreement between the measured and the calculated results was observed

    Iron limitation enhances acyl homoserine lactone (AHL) production and biofilm formation in clinical isolates of Acinetobacter baumannii

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    Acinetobacter baumannii is an important source of infections in intensive care units (ICUs) of our hospitals in Kerman, Iran and the most frequently isolated strains produce biofilm. There is a little information about role of iron (Fe) levels on acyl homoserine lactone (AHL) production and biofilm formation in this microorganism. In the present study, we investigated the influence of iron-III limitation on AHL, siderophore, catechol and virulence factors in the biofilm forming clinical strains of A. baumannii. A total of 65 non-duplicated multidrug resistance (MDR) strains of A. baumannii were isolated from patients in ICUs of 2 hospitals in Kerman, Iran. Antibiotic susceptibility, siderophore and other iron chelators, hemolysis, cell twitching motility, capsule, gelatinase and DNase were studied. Presence of quorum sensing, LuxI and LuxR genes was detected by multiplex-PCR. AHL activity quantified by colorimetric method and the functional groups were determined by Fourier Transform Infra-Red Spectroscopy (FT-IR). Biofilm formation was detected by microtiter plate technique. All of the isolates were resistant to third generation of cephalosporins, ciprofloxacin, levofloxacin, tetracycline, whereas, 78% and 81% were resistant to amikacin and carbapenems, respectively. The siderophore activity was highest at 20 mM Fe3C (70%); however, it decreased to 45% as concentration of Fe3C increased to 80 mM. Furthermore, screening of the isolates for LuxI and LuxR genes showed that presence of both genes required in the isolates with high AHL activity. FT-IR analysis indicated CDO bond of the lactone ring and primary amides. Significantly, a higher amount of AHL (70%) was detected in the presence of low concentration of iron-III (20 mM); as iron concentration increased to 80 mM, the AHL activity was reduced to 40% (P � 0.05). All the isolates exhibited twitching motility and had a capsule. No any gelatinase or DNase activity was detected. Quantification of the biofilm formation introduced 23 isolates with efficient attachment to microplate wells and strong biofilm. We found that both the AHL production and biofilm formation were regulated by iron concentration in a dose dependent manner. These findings provide evidence that iron limitation plays an important regulatory role in AHL and siderophore production resulting in strong or weak biofilm, thereby helping the organism to persist in less available micronutrient environment

    Molecular Analysis and Expression of bap Gene in Biofilm-Forming Multi-Drug-Resistant Acinetobacter baumannii

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    Background: Acinetobacter baumanniiis commonly resistant to nearly all antibiotics due to presence of antibiotic resistance genes and biofilm formation. In this study we determined the presence of certain antibiotic-resistance genes associated with biofilm production and the influence of low iron concentration on expression of the biofilmassociated protein gene (bap) in development of biofilm among multi-drug-resistant A. baumannii (MDRAB). Methods: Sixty-five MDRAB isolates from clinical samples were collected. Molecular typing was carried out by random amplified polymorphism DNA polymerase chain reaction (RAPD-PCR). Biofilm formation was assayed by the microtiter method. Results: The sequence of bap was determined and deposited in the GenBank database (accession no. KR080550.1). Expression of bap in the presence of low iron was analyzed by relative quantitative real time PCR (rqRT-PCR). Nearly half of the isolates belonged to RAPD-types A and B remaining were either small clusters or singleton. The results of biofilm formation revealed that 23 (35.4%), 18 (27.7%), 13 (20%), and 11 (16.9%) of the isolates had strong, moderate, weak, and no biofilm activities, respectively. ompA and csuE genes were detected in all, while bap and blaPER-1 were detected in 43 (66%) and 42 (64%) of the isolates that showed strong and moderate biofilm activities (p ≤ 0.05), respectively. Analysis ofbapexpression by rqRT-PCR revealed five isolates with fourfold bap overexpression in the presence of low iron concentration (20 µM). Conclusion: The results suggest thatbapoverexpression may influence biofilm formation in presence of low iron concentration
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