270 research outputs found
Solar Cells, Lambert W and the LogWright Functions
Algorithms that calculate the current-voltage (I-V) characteristics of a solar cell play an important role in processes that aim to improve the efficiency of a solar cell. I-V characteristics can be obtained from different models used to represent the solar cell, and the single diode model is a simple yet accurate model for common field implementations. However, the I-V characteristics are obtained by solving implicit equations, which involve repeated iterations and inherent errors associated with numerical methods used. Some methods use the Lambert W function to get an exact explicit formula, but often causes numerical overflow problems. The present work discusses an algorithm to calculate I-V characteristics using the LogWright function, a transformation of the Lambert W function, which addresses the problem of arithmetic overflow that occurs in the Lambert W implementation. An implementation of this algorithm is presented and compared against other algorithms in the literature. It is observed that in addition to addressing the numerical overflow problem, the algorithm based on the LogWright function offers speed benefits while retaining high precision
Transformation of β-Ni(OH)2to NiO nano-sheets via surface nanocrystalline zirconia coating: Shape and size retention
Shape and size of the synthesized NiO nano-sheets were retained during transformation of sheet-like β-Ni(OH)2to NiO at elevated temperatures via nano-sized zirconia coating on the surface of β-Ni(OH)2. The average grain size was 6.42 nm after 600 °C treatment and slightly increased to 10 nm after 1000 °C treatment, showing effective sintering retardation between NiO nano-sheets. The excellent thermal stability revealed potential application at elevated temperatures, especially for high temperature catalysts and solid-state electrochemical devices
Nanomaterial-based Sensors for the Study of DNA Interaction with Drugs
The interaction of drugs with DNA has been searched thoroughly giving rise to an endless number of findings of undoubted importance, such as a prompt alert to harmful substances, ability to explain most of the biological mechanisms, or provision of important clues in targeted development of novel chemotherapeutics. The existence of some drugs that induce oxidative damage is an increasing point of concern as they can cause cellular death, aging, and are closely related to the development of many diseases. Because of a direct correlation between the response, strength/ nature of the interaction and the pharmaceutical action of DNA-targeted drugs, the electrochemical analysis is based on the signals of DNA before and after the interaction with the DNA-targeted drug. Nowadays, nanoscale materials are used extensively for offering fascinating characteristics that can be used in designing new strategies for drug-DNA interaction detection. This work presents a review of nanomaterials (NMs) for the study of drug-nucleic acid interaction. We summarize types of drug-DNA interactions, electroanalytical techniques for evidencing these interactions and quantification of drug and/or DNA monitoring
Cardiac tumours in children
Cardiac tumours are benign or malignant neoplasms arising primarily in the inner lining, muscle layer, or the surrounding pericardium of the heart. They can be primary or metastatic. Primary cardiac tumours are rare in paediatric practice with a prevalence of 0.0017 to 0.28 in autopsy series. In contrast, the incidence of cardiac tumours during foetal life has been reported to be approximately 0.14%. The vast majority of primary cardiac tumours in children are benign, whilst approximately 10% are malignant. Secondary malignant tumours are 10–20 times more prevalent than primary malignant tumours. Rhabdomyoma is the most common cardiac tumour during foetal life and childhood. It accounts for more than 60% of all primary cardiac tumours. The frequency and type of cardiac tumours in adults differ from those in children with 75% being benign and 25% being malignant. Myxomas are the most common primary tumours in adults constituting 40% of benign tumours. Sarcomas make up 75% of malignant cardiac masses. Echocardiography, Computing Tomography (CT) and Magnetic Resonance Imaging (MRI) of the heart are the main non-invasive diagnostic tools. Cardiac catheterisation is seldom necessary. Tumour biopsy with histological assessment remains the gold standard for confirmation of the diagnosis. Surgical resection of primary cardiac tumours should be considered to relieve symptoms and mechanical obstruction to blood flow. The outcome of surgical resection in symptomatic, non-myxomatous benign cardiac tumours is favourable. Patients with primary cardiac malignancies may benefit from palliative surgery but this approach should not be recommended for patients with metastatic cardiac tumours. Surgery, chemotherapy and radiotherapy may prolong survival. The prognosis for malignant primary cardiac tumours is generally extremely poor
Stibnite Nanoparticles as a New Stabilizer for Poly (Methyl Methacrylate) Exposed to Gamma Irradiation
Photobiological synthesis of noble metal nanoparticles using Hydrocotyle asiatica and application as catalyst for the photodegradation of cationic dyes
Simulation and qualitative analysis of glucose variability, mean glucose, and hypoglycemia after subcutaneous insulin therapy for stress hyperglycemia
Synthesis, characterization and studies on optical properties of indium doped ZnO nanoparticles
561-565Indium doped zinc oxide hierarchical
nanostructures have been synthesized using a simple aqueous solution based
method. A change in morphology from hierarchical nanostructures in ZnO to
nanorods after doping with indium has been observed. The optical properties of
nanostructures have been investigated using diffuse reflectance and
photoluminescence spectroscopy. The band gap of zinc oxide nanoparticles
changes after the incorporation of indium and a blue shift of band gap is
observed
Alternating current conductivity and electrical conductivity relaxation in an intercalated polymer electrolyte
Sodium cations solvated by polyethylene oxide have been confined by intercalation in the interlamellar space of an insulating layered solid, CdPS3. The frequency-dependent conductivity and the associated conductivity relaxation in the intercalated polymer electrolyte have beenb investigated. The temperature-dependent conductivity displays a distinct change in behavior at T similar to 225 K. Below 225 K the dc conductivity, sigma(dc), shows an Arrhenius temperature dependence, while for T > 225 K sigma(dc) rises sharply and follows the Vogel-Tamann Fulcher relation, characteristic of ionic motion coupled to polymer relaxation modes. An analysis of the frequency dependent conductivity using the electrical modulus representation showed that the electrical conductivity relaxation may be described in terms of the stretched exponential correlation function in the time domain, phi(t) = exp(-t/tau(sigma))(beta). The absence of any anionic contribution to the electrical response makes these intercalated polymer electrolyte systems attractive for fundamental studies on ionic motion in disordered polymeric media
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