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Mahmoud Y.,Worcester Polytechnic Institute | El-Saadany E.F.,PI | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Energy Conversion | Year: 2017

PV modules operating under partially shaded conditions exhibit multiple peaks in their output power curves, which cause the majority of the maximum power point tracking (MPPT) techniques to become trapped in a local power peak. This unfortunately leads to additional energy losses that could otherwise be harvested if the global maximum power peak (GMPP) were correctly tracked. The available MPPT methods that are able to track the GMPP require periodic scanning of the PV curve, which disturbs the operation of the system and causes energy losses. A new MPPT technique is proposed in this paper that is distinguished by its ability to find the GMPP without the need for periodic curve scanning. The proposed method utilizes the mathematical model of the PV module, as well as the irradiances received by its PV cells, to analytically calculate the location of the GMPP. The required irradiances are innovatively estimated using an image of the PV module captured by an optical camera. The proposed method is also combined with the perturb and observe method to compensate for errors in the model or irradiance estimation. Experimental verifications are conducted to validate the effectiveness of the proposed MPPT method under various shading scenarios. © 2016 IEEE.


News Article | May 4, 2017
Site: www.prweb.com

Precision positioning systems industry leader PI (Physik Instrumente) has released a higher performance model of its successful Mercury Stepper Motion controller. Stepper motors take up discrete positions in a revolution of a constant distance. Typical commercial models provide 200 to 1000 full steps per revolution. Designed to deliver more than 2,000 times the basic motor resolution, the C-663.12 Mercury controller is the newest addition to PI’s suite of motion control solutions. Compact Motion Controller, A Complete Package, Daisy Chain for Multi-Axis Operation PI’s compact C-663.12 motion controller is designed for 2-phase stepper motors, in open-loop or closed-loop operation commanded by USB or RS-232. Up to 16 units can be combined via daisy chain to operate multi-axis motion systems. The Mercury controller includes a 48-V wide-range-input power supply, and all cables required for operation. Programmable digital and analog I/O lines and input lines for limit and reference point switches controlled via TTL signals are also integrated. Data Recorder, Auto-Calibration ID Chip, Quick Start Up, Comprehensive Software Package The C-663.12 is equipped with a data recorder for high speed tracing, ID chip compatibility for quick start-up and on-the-fly parameter changes, and exchange of system components without recalibration. The controllers are delivered with extensive software packages, including drivers for LabVIEW, as well as dynamic libraries for Windows and Linux. Standard and Custom Solutions PI has over 4 decades of experience providing in-house engineered precision motion control solutions, and can quickly modify existing product designs or provide a fully customized OEM part to fit the exact requirements of the customer’s application. About PI PI is a leading manufacturer of precision motion control equipment, air bearing stages, piezoelectric solutions, and hexapod parallel-kinematics for semiconductor applications, photonics, bio-nano-technology and medical engineering. PI has been developing and manufacturing standard & custom precision products with piezoceramic and electromagnetic drives for 4 decades. The company has been ISO 9001 certified since 1994 and provides innovative, high-quality solutions for OEM and research. The PI group employs more than 1,000 people worldwide in 15 subsidiaries and R&D / engineering centers on 3 continents.


Mahmoud S.L.,ADCO | Othman A.A.,Al - Azhar University of Egypt | El Kadi H.H.,Al - Azhar University of Egypt | Berteussen K.,P.I.
Society of Petroleum Engineers - Abu Dhabi International Petroleum Exhibition and Conference 2012, ADIPEC 2012 - Sustainable Energy Growth: People, Responsibility, and Innovation | Year: 2012

An azimuthal seismic study for fault and fracture identification was carried out on a giant onshore carbonate oil reservoir in the U.A.E., Middle East. The seismic reflectivity analysis was performed using advanced independently processed azimuthal sectors from compressional waves. The seismic attributes demonstrated superior capability of defining accurately the detailed reservoir faults and the fracture networks. Although the full azimuthal study achieved excellent results, the azimuthal stacks were observed to sharpen the reservoir subtle structural features. Beside the traditional land seismic data processing, additional challenges were to properly process the seismic data due to the surface topography and the lateral variations in subsurface rock properties. Azimuthal processing successfully demonstrated: a) Improved fault imaging relative to the available conventionally processed seismic data. b) Additional information about the seismic anisotropy in the reservoir zones. The analysis showed encouraging results and a relatively good match to known fault/fracture locations. The successful results of the study suggest that high quality 3D wide azimuthal seismic data with relative true amplitude preservation can be used to identify the fracture permeability pathways in carbonate reservoirs. The azimuthal sectors study and results facilitated the quantification of the presence of faults, and suggest that fractured zones can be identified. Another important procedure in this study is the use of the integrated approach during processing and interpretation. Overall, the results of this Azimuthal Study for fractured carbonate reservoir characterization revealed encouraging outputs and valuable guidelines for similar studies in the future. Copyright 2012, Society of Petroleum Engineers.


El Wazir Z.,ADCO | Steuber T.,PI | Duan R.,PI | Muller K.,ADCO
Society of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014: Unlocking Energy Through Innovation, Technology and Capability | Year: 2014

The stratigraphy of Barremian - Aptian carbonate platforms of the Middle East and their complex architecture are relatively well constrained since they host several large reservoirs and have therefore attracted substantial research activity. Nevertheless, regionaland local correlation of sedimentary sequences can be difficult. Carbonate platforms with their complex internal architecture provide an excellent opportunity to investigate the response of carbonate sedimentary systems to sea-level change. We have used a combination of carbon and Sr-isotope chemostratigraphy to test regional sequence-stratigraphic models, improve local correlation of sedimentary sequences, and place them in a global context of environmental change by using numerical ages derived from Sr-isotope stratigraphy. Examples are provided how to derive precise numerical ages using Sr-isotope stratigraphy. Most importantly, diagenetic alteration of the original seawater Sr-isotopic composition must be excluded by careful selection of sample material and geochemical screening. Precision of age-dating is +/- 0.7 my in the case study presented, and factors affecting the reliability of numerical ages are discussed. Once the numerical ages of sequence boundaries and other correlative surfaces are established, the validity of problematic correlations can be easily tested. Fifteen cored wells have been sampled for isotopes analysis and used for providing examples of age-dating of sedimentary sequences along and across the Aptian platform margin in the subsurface of the UAE, including the Late Aptian prograding units that are particularly difficult to correlate. Chemostratigraphy, and particularly numerical ages, allow for the correlation with global environmental change (oceanic anoxic events, extinctionevents of carbonate producers, sea-level change), that ultimately leads to an improved understanding of the evolution of the regional Aptian carbonate depositional systems and the distribution of their characteristic reservoir facies. Copyright 2014, International Petroleum Technology Conference.


Marygold S.J.,University of Cambridge | Leyland P.C.,University of Cambridge | Leyland P.C.,Brnikat Ltd. | Seal R.L.,University of Cambridge | And 43 more authors.
Nucleic Acids Research | Year: 2013

An accurate, comprehensive, non-redundant and up-to-date bibliography is a crucial component of any Model Organism Database (MOD). Principally, the bibliography provides a set of references that are specific to the field served by the MOD. Moreover, it serves as a backbone to which all curated biological data can be attributed. Here, we describe the organization and main features of the bibliography in FlyBase (flybase.org), the MOD for Drosophila melanogaster. We present an overview of the current content of the bibliography, the pipeline for identifying and adding new references, the presentation of data within Reference Reports and effective methods for searching and retrieving bibliographic data. We highlight recent improvements in these areas and describe the advantages of using the FlyBase bibliography over alternative literature resources. Although this article is focused on bibliographic data, many of the features and tools described are applicable to browsing and querying other datasets in FlyBase. © The Author(s) 2012.

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