Plant Identification based on Fractal Refinement Technique (FRT)

AbstractWe propose here a new algorithm for plant classification and identification based on fractal dimension. It is a simple and efficient technique for identifying plants using three levels of fractal refinement on leaf images. Contour, Contour-Nervure and Nervure fractal dimensions are computed and are used in the first, second and third level of refinement respectively. A 50 set species with each set containing 10 samples are used for training the algorithm. The performance of the algorithm was examined with a test set of 500 leaves arbitrarily selected from different groups of species. The fault acceptance rate (FAR), the fault rejection rate (FRR) and the classification accuracy of the algorithm were analyzed experimentally and demonstrated that the proposed method has an accuracy rate of 84%

Vortex shedding patterns, their competition, and chaos in flow past inline oscillating rectangular cylinders

The flow past inline oscillating rectangular cylinders is studied numerically at a Reynolds number representative of two-dimensional flow. A symmetric mode, known as S-II, consisting of a pair of oppositely-signed vortices on each side, observed recently in experiments, is obtained computationally. A new symmetric mode, named here as S-III, is also found. At low oscillation amplitudes, the vortex shedding pattern transitions from antisymmetric to symmetric smoothly via a regime of intermediate phase. At higher amplitudes, this intermediate regime is chaotic. The finding of chaos extends and complements the recent work of Perdikaris et al. [1]. Moreover it shows that the chaos results from a competition between antisymmetric and symmetric shedding modes. Rectangular cylinders rather than square are seen to facilitate these observations. A global, and very reliable, measure is used to establish the existence of chaos.Comment: Submitted to the Physics of Fluid

Temperature dependence of dark current properties of InGaAs/GaAs quantum dot solar cells

Self-assembledIn₀.₅Ga₀.₅As/GaAsquantum dotsolar cell (QDSC) was grown by metal organic chemical vapor deposition. Systematic measurements of dark current versus voltage (I-V) characteristics were carried out from 30 to 310 K. Compared with the reference GaAssolar cell, the QDSC exhibits larger dark current however its ideality factor (n) was smaller, which cannot be straightly interpreted by the conventional diode models. These results are important for the fundamental understanding of QDSC properties and further implementation of new solar cell designs for improved efficiency.The authors would like to acknowledge financial support from the Australian Research Council and facility support from the Australian National Fabrication Facility ACT node

Omnidirectional Current Enhancement From Laminated Moth-Eye Textured Polymer Packaging for Large-Area, Flexible III-V Solar Modules

Epitaxial lift-off (ELO) processes have allowed for cheaper development of mechanically flexible, ultra-thin, and high- efficiency III-V solar cells. ELO solar cells are natural candidates for applications where solar cells must conform to curved surfaces and provide high efficiency and high specific power generation (W/kg). Such examples include power generation for unmanned aerial vehicles, electric vehicles, and portable electrical power. However, when considering these mobile solar applications, large variations in angle of incidence (AOI) that inevitably occur can greatly decrease overall system efficiency due to significant Fresnel reflections. In this article, we demonstrate the integration of moth- eye antireflection nanostructures on the polymer packaging layer of ELO solar cell arrays using a low-cost, colloidal self-assembly process. The moth-eye structures mitigate Fresnel reflections and increase photocurrent generation over all measured angles of inci- dence relative to ELO solar cell arrays with traditional untextured polymer packaging. The nanostructures survive a commercial lam- ination procedure, an important criterion that must be met to ensure the feasibility of integration into commercial processing. Outdoor solar characterization measurements are performed and, under direct optical illumination, moth-eye textured solar cell ar- rays show a maximum Isc enhancement of ∼58% at 79° AOI rela- tive to traditional untextured polymer packaged solar cell arrays, and when exposed to both direct and diffuse optical illumination a maximum Isc enhancement of ∼23% at 79° AOI is observed.Center for Dynamics and Control of Material

Influence of Organic Acids on Diltiazem HCl Release Kinetics from Hydroxypropyl Methyl Cellulose Matrix Tablets

The matrix tablets of diltiazem hydrochloride were prepared by direct compression using hydroxypropyl methyl cellulose (HPMC) and various amounts (2.5%, 5.0%, 10% and 20%) of citric acid, malic acid and succinic acid. The characterization of physical mixture of drug and organic acids was performed by Infra-red spectroscopy. An organic acid was incorporated to set up a system bringing about gradual release of this drug. The influence of organic acids on the release rate were described by the Peppas equation: M t /M∞ = Kt n and Higuchi’s equation: Q t = K1t1/2. The addition of organic acids and the pH value of medium could notably influence the dissolution behavior and mechanism of drug-release from matrices. Increasing amounts of organic acid produced an increase in drug release rate, which showed a good linear relationship between contents of organic acid and drug accumulate release (%) in phosphate buffer, pH 7.4. The drug release increased significantly (P < 0.05) with use of succinic acid in tablet formulation. Increasing amounts of succinic acid above 10% produced decreasing values of n and increasing values of k, in a linear relationship, which indicated there was a burst release of drug from the matrix. Optimized formulations are found to be stable upon 3-month study

Photonic system for real-time detection, discrimination, and quantification of microbes in air

We report the results of the non-invasive photonic system AUM for remote detection and characterization of different pathogenic bacterial strains and mixtures. AUM applies the concepts of elastic light scattering, statistical mechanics, artificial intelligence, and machine learning to identify, classify and quantify various microbes in the scattering volume in real-time and, therefore, can become a potential tool in controlling and managing diseases caused by pathogenic microbes

Novi kopolimerni zwitterionski matriksi za polagano oslobađanje verapamil hidroklorida

Stable co-polymer [vinyl acetate-co-3-dimethyl(methacryloyloxyethyl)ammonium propane sulfоnate, p(VA-co-DMAPS)] latex of different compositions has been synthesized for the first time by emulsifier-free emulsion copolymerization. The unusual “overshooting” behavior of the co-polymer tablets has been explained by the formation of specific clusters from the opposite oriented dipoles zwitterionic species. The change of their concentration with the DMAPS unit fraction (mDMAPS), pH and ionic strength has been considered responsible for the differences observed in the swelling kinetics. The results obtained prove that mDMAPS and ionic strength could be used to control the swelling degree of the p(VA-co-DMAPS) matrices. In this way, p(VA-co-DMAPS) matrices could be effectively used to control the sustained release of drugs with basic properties like verapamil hydrochloride from model tablets.Metodom emulzijske polimerizacije sintetiziran je novi stabilni kopolimer [vinil acetat-ko-3-dimetil(metakriloiloksietill)amonijev propan sulfоnat, p(VA-co-DMAPS)] lateks promjenjivog sastava. Neobično “overshooting” ponašanje tableta pripravljenih iz tog kopolimera objašnjava se stvaranjem specifičnih klastera suprotno rijentiranih dipola zwitterionskih specija. Proučavan je utjecaj udjela DMAPS jedinica (mDMAPS), pH i ionske jakosti na kinetiku bubrenja. Dobiveni rezultati dokazuju da se promjenom mDMAPS i ionske jakosti može kontrolirati stupanj bubrenja p(VA-co-DMAPS) matriksa i oslobađanje verapamil hidroklorida iz tableta pa se ti matriksi mogu upotrijebiti za polagano oslobađanje bazičnih lijekova srodnih verapamilu