295 research outputs found

    An optimal day-ahead load scheduling approach based on the flexibility of aggregate demands

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    The increasing trends of energy demand and renewable integration call for new and advanced approaches to energy management and energy balancing in power networks. Utilities and network system operators require more assistance and flexibility shown from consumers in order to manage their power plants and network resources. Demand response techniques allow customers to participate and contribute to the system balancing and improve power quality. Traditionally, only energy-intensive industrial users and large customers actively participated in demand response programs by intentionally modifying their consumption patterns. In contrast, small consumers were not considered in these programs due to their low individual impact on power networks, grid infrastructure and energy balancing. This paper studies the flexibility of aggregated demands of buildings with different characteristics such as shopping malls, offices, hotels and dwellings. By using the aggregated demand profile and the market price predictions, an aggregator participates directly in the day-ahead market to determine the load scheduling that maximizes its economic benefits. The optimization problem takes into account constraints on the demand imposed by the individual customers related to the building occupant comfort. A case study representing a small geographic area was used to assess the performance of the proposed method. The obtained results emphasize the potential of demand aggregation of different customers in order to increase flexibility and, consequently, aggregator profits in the day-ahead market.The authors kindly acknowledge the support of the Spanish Ministry of Economy and Competitiveness project RESmart (ENE2013-48690-C2-2-R)

    Organic Pollutants, Heavy Metals and Toxicity in Oil Spill impacted Salt Marsh Sediment Cores, Staten Island, New York City, USA

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    Sediment cores from Staten Island's salt marsh contain multiple historical oil spill events that impact ecological health. Microtox solid phase bioassay indicated moderate to high toxicity. Multiple spikes of TPH (6524 to 9586 mg/kg) and Σ16 PAH (15.5 to 18.9 mg/kg) were co-incident with known oil spills. A high TPH background of 400–700 mg/kg was attributed to diffuse sources. Depth-profiled metals Cu (1243 mg/kg), Zn (1814 mg/kg), Pb (1140 mg/kg), Ni (109 mg/kg), Hg (7 mg/kg), Cd 15 (mg/kg) exceeded sediment quality guidelines confirming adverse biological effects. Changes in Pb206/207 suggested three metal contaminant sources and diatom assemblages responded to two contamination events. Organic and metal contamination in Saw Mill Creek Marsh may harm sensitive biota, we recommend caution in the management of the 20–50 cm sediment interval because disturbance could lead to remobilisation of pre-existing legacy contamination into the waterway

    The role of manufacturing and market managers in strategy development:lessons from three companies

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    According to researchers and managers, there is a lack of agreement between marketing and manufacturing managers on critical strategic issues. However, most of the literature on the subject is anecdotal and little formal empirical research has been done. Three companies are investigated to study the extent of agreement/disagreement between manufacturing and marketing managers on strategy content and process. A novel method permits the study of agreement between the two different functional managers on the process of developing strategy. The findings consistently show that manufacturing managers operate under a wider range of strategic priorities than marketing managers, and that manufacturing managers participate less than marketing managers in the strategy development process. Further, both marketing and manufacturing managers show higher involvement in the strategy development process in the latter stages of the Hayes and Wheelwright four-stage model of manufacturing’s strategic role

    Remote practicals in the time of coronavirus, a multidisciplinary approach

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    Due to the COVID-19 pandemic, universities across the world have curtailed face to face teaching. Associated with this is the halt to the delivery of the practical experience required of engineering students. The Multidisciplinary Engineering Education (MEE) team at The University of Sheffield have responded to this problem in an efficient and effective way by recording laboratory experiences and putting videos, quizzes and data online for students to engage with. The focus of this work was on ensuring all Learning Outcomes (LOs) for modules and courses were preserved. Naturally, practical skills cannot be easily provided using this approach, but it is an effective way of getting students to interact with real data, uncertainty and equipment which they cannot access directly. A number of short case studies from across the range of engineering disciplines are provided to inspire and guide other educators in how they can move experiments on line in an efficient and effective manner. No student feedback is available at the time of writing, but anecdotal evidence is that this approach is at least acceptable for students and a way of collecting future feedback is suggested. The effort expended on this approach and the artefacts produced will support student learning after the initial disruption of the lockdown has passed

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Sub-shell closure and shape coexistence in the transitional nucleus Zr 98

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    In the rapid shape change from spherical to deformed nuclei in the Z=40 Zr isotopic chain, recent work has identified shape coexistence in Zr96. Between Zr96 and the strongly deformed Zr100, Zr98 is expected to also exhibit coexistence of nuclear shapes. The degree of mixing between different configurations is mainly determined by the nucleon-nucleon interactions. For nuclear model predictions, experimental constraints are needed, but they are barely available for Zr98. To study low-lying transitions in Zr98, a Coulomb excitation experiment was conducted at the Argonne Tandem-Linac Accelerator System (ATLAS) facility using a Zr98 beam extracted from the Californium Rare Ion Breeder Upgrade (CARIBU) ion source and Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) for γ-ray spectroscopy coupled to the compact heavy ion counter (CHICO2) for ion detection. This paper reports on the first decisive deduction of the B(E2;21+→01+) transition strength in Zr98 and on its interpretation

    First direct observation of enhanced octupole collectivity in 146Ba

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    The octupole strength present in the neutron-rich, radiocative nucleus 146Ba has been experimentally determined for the first time using Coulomb excitation. To achieve this, A=146 fission fragments from CARIBU were post-accelerated by the Argonne Tandem Linac Accelerator System (ATLAS) and impinged on a thin 208Pb target. Using the GRETINA γ-ray spectrometer and the CHICO2 heavy-ion counter, the reduced transition probability B(E3; 3-→0+) was determined as 48(+21-29) W.u. The new result provides further experimental evidence for the presence of a region of octupole deformation surrounding the neutron-rich barium isotopes

    Shape coexistence and the role of axial asymmetry in 72Ge

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    The quadrupole collectivity of low-lying states and the anomalous behavior of the 02+ and 23+ levels in 72Ge are investigated via projectile multi-step Coulomb excitation with GRETINA and CHICO-2. A total of forty six E2 and M1 matrix elements connecting fourteen low-lying levels were determined using the least-squares search code, gosia. Evidence for triaxiality and shape coexistence, based on the model-independent shape invariants deduced from the Kumar-Cline sum rule, is presented. These are interpreted using a simple two-state mixing model as well as multi-state mixing calculations carried out within the framework of the triaxial rotor model. The results represent a significant milestone towards the understanding of the unusual structure of this nucleus
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