163 research outputs found
Agrobacterium mediated transformation of Tunisian Cucumis melo cv. maazoun
Transgenic Cucumis melo cv. Maazoun containing the neomycin phosphotransferase II (NPT II) chimeric gene conferring resistance to kanamycin were obtained from cotyledons explants inoculatedwith Agrobacterium tumefaciens (GV3101) that contained the binary vector plasmid pADI. Transformed shoots were obtained on Murashige and Skoog medium supplemented with 1.50 mgl-1 IAA, 0.10mgl-1BAP, 0.01 mgl-1 NAA and 6 mgl-1 kinetin. Transformants were selected by using only 100 mgl-1 of kanamycin and 4 days of pre-culture. Putative transformants were confirmed for transgene insertion through polymerase chain reaction (PCR) analysis. From the inoculated explants, 6.66% produced transgenic shoots
An effective control algorithm for dynamic voltage restorer under symmetrical and asymmetrical grid voltage conditions
Introduction. Voltage sag, which is associated to a transitory drop in the root mean square voltage characterizing an electrical source network. During these perturbations, the corresponding electronic customers and devices will suffer from serious operating troubles causing dangerous damages. Purpose. In order to attenuate this disturbance effects, the Controlled Dynamic Voltage Restorer constitutes a very interesting solution among many others that have been proposed. The novelty of the proposed work consists in presenting an enhanced algorithm to control efficiently the dynamic voltage restorer when voltage sag is suddenly occurred. Methods. The proposed algorithm is based on an instantaneous phase locked loop using a multi variable filter to synthesize unitary signals involved in compensation voltages computation relative to the sag apparition. Practical value. A detailed study concerning typical voltage sag, which is consolidated by simulation and experimental results, is conducted to show the used algorithm’s effectiveness to cancel the corresponding voltage sag.Вступ. Провал напруги, який пов’язаний із тимчасовим падінням середньоквадратичної напруги, характеризує мережу джерел електричної енергії. Під час цих збурень відповідні споживачі (електронні прилади та інші пристрої) будуть страждати від серйозних проблем у їхній експлуатації, що спричиняють небезпечні пошкодження. Призначення. Для того, щоб послабити вплив цих збурень, контрольований динамічний відновник напруги видається дуже цікавим рішенням серед багатьох інших, які були запропоновані. Новизна запропонованої роботи полягає у представленні вдосконаленого алгоритму ефективного управління динамічним відновником напруги, коли раптово відбувається провал напруги. Методи. Запропонований алгоритм базується на миттєвому фазовому замкненому контурі з використанням багатоваріантного фільтра для синтезу унітарних сигналів, що беруть участь у обчисленні напруги компенсації стосовно прояву провалу. Практичне значення. Детальне дослідження стосовно типового провалу напруги, яке узагальнено за допомогою моделювання та експериментальних результатів, проведено, щоб показати ефективність використовуваного алгоритму для ліквідації відповідного провалу напруги
Solar cell degradation under open circuit condition in out-doors-in desert region
AbstractThe reliability of solar cells is an important parameter in the design of photovoltaic systems and particularly for cost estimation. Solar cell degradation is the result of various operating conditions; temperature is one of most important factors. Installed PV modules in desert regions are subjected to various temperature changes with significant gradient leading to accelerated degradation. In the present work, we demonstrate the influence of open-circuit condition on the degradation of PV modules. The experiment is carried out in the desert region of ADRAR (southern Algeria) using two modules IJISEL of single-crystal silicon. A continuous monitoring allows analysis of both performances of modules for duration of 330days. The module in open-circuit condition reaches higher temperature means than the module in charging condition; therefore, it undergoes a higher degradation. By simulation, we found that the life of a PV module (whose power output is close to 50%) in a condition of an open-circuit in the desert region could be reduced to 4years, and that has a significant impact on economy
Polarons as stable solitary wave solutions to the Dirac-Coulomb system
We consider solitary wave solutions to the Dirac--Coulomb system both from
physical and mathematical points of view. Fermions interacting with gravity in
the Newtonian limit are described by the model of Dirac fermions with the
Coulomb attraction. This model also appears in certain condensed matter systems
with emergent Dirac fermions interacting via optical phonons. In this model,
the classical soliton solutions of equations of motion describe the physical
objects that may be called polarons, in analogy to the solutions of the
Choquard equation. We develop analytical methods for the Dirac--Coulomb system,
showing that the no-node gap solitons for sufficiently small values of charge
are linearly (spectrally) stable.Comment: Latex, 26 page
Stable directions for small nonlinear Dirac standing waves
We prove that for a Dirac operator with no resonance at thresholds nor
eigenvalue at thresholds the propagator satisfies propagation and dispersive
estimates. When this linear operator has only two simple eigenvalues close
enough, we study an associated class of nonlinear Dirac equations which have
stationary solutions. As an application of our decay estimates, we show that
these solutions have stable directions which are tangent to the subspaces
associated with the continuous spectrum of the Dirac operator. This result is
the analogue, in the Dirac case, of a theorem by Tsai and Yau about the
Schr\"{o}dinger equation. To our knowledge, the present work is the first
mathematical study of the stability problem for a nonlinear Dirac equation.Comment: 62 page
Automatic annotation of coral reefs using deep learning
Healthy coral reefs play a vital role in maintaining biodiversity in tropical marine ecosystems. Deep sea exploration and imaging have provided us with a great opportunity to look into the vast and complex marine ecosystems. Data acquisition from the coral reefs has facilitated the scientific investigation of these intricate ecosystems. Millions of digital images of the sea floor have been collected with the help of Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs). Automated technology to monitor the health of the oceans allows for transformational ecological outcomes by standardizing methods for detecting and identifying species. Manual annotation is a tediously repetitive and a time consuming task for marine experts. It takes 10-30 minutes for a marine expert to meticulously annotate a single image. This paper aims to automate the analysis of large available AUV imagery by developing advanced deep learning tools for rapid and large-scale automatic annotation of marine coral species. Such an automated technology would greatly benefit marine ecological studies in terms of cost, speed, accuracy and thus in better quantifying the level of environmental change marine ecosystems can tolerate. We propose a deep learning based classification method for coral reefs. We also report the application of the proposed technique towards the automatic annotation of unlabelled mosaics of the coral reef in the Abrolhos Islands, Western Australia. Our proposed method automatically quantifies the coral coverage in this region and detects a decreasing trend in coral population which is in line with conclusions by marine ecologists
Coral classification with hybrid feature representations
© 2016 IEEE. Coral reefs exhibit significant within-class variations, complex between-class boundaries and inconsistent image clarity. This makes coral classification a challenging task. In this paper, we report the application of generic CNN representations combined with hand-crafted features for coral reef classification to take advantage of the complementary strengths of these representation types. We extract CNN based features from patches centred at labelled pixels at multiple scales. We use texture and color based hand-crafted features extracted from the same patches to complement the CNN features. Our proposed method achieves a classification accuracy that is higher than the state-of-art methods on the MLC benchmark dataset for corals
A High Resolution Color Image Restoration Algorithm for Thin TOMBO Imaging Systems
In this paper, we present a blind image restoration algorithm to reconstruct a high resolution (HR) color image from multiple, low resolution (LR), degraded and noisy images captured by thin (< 1mm) TOMBO imaging systems. The proposed algorithm is an extension of our grayscale algorithm reported in [1] to the case of color images. In this color extension, each Point Spread Function (PSF) of each captured image is assumed to be different from one color component to another and from one imaging unit to the other. For the task of image restoration, we use all spectral information in each captured image to restore each output pixel in the reconstructed HR image, i.e., we use the most efficient global category of point operations. First, the composite RGB color components of each captured image are extracted. A blind estimation technique is then applied to estimate the spectra of each color component and its associated blurring PSF. The estimation process is formed in a way that minimizes significantly the interchannel cross-correlations and additive noise. The estimated PSFs together with advanced interpolation techniques are then combined to compensate for blur and reconstruct a HR color image of the original scene. Finally, a histogram normalization process adjusts the balance between image color components, brightness and contrast. Simulated and experimental results reveal that the proposed algorithm is capable of restoring HR color images from degraded, LR and noisy observations even at low Signal-to-Noise Energy ratios (SNERs). The proposed algorithm uses FFT and only two fundamental image restoration constraints, making it suitable for silicon integration with the TOMBO imager
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