Photovoltaic powered regulated cathodic protection system

The cathodic protection (CP) system objective is to protect metallic structures against corrosion caused by chemical reaction between metallic structures and surrounding mediums, such as soil or water. To overcome such a problem, a sacrificing anode is connected to the protected structure (which acts as a cathode) through a DC power supply. As a result, a current passes from the sacrificing anode to the protected cathode. This leads to anode corrosion rather than causing the cathode (protected structure) corrosion. To stop the corrosion, the protected structure requires a constant current determined by structure metal, area, and the surrounding medium. The major difficulty in achieving this condition is the variation of surrounding medium resistivity due to climatic condition changes. For example, rains as well as humidity decrease soil resistivity, and as a result the DC current increases and a harmful overprotection may take place. Both corrosion and overprotection are harmful for the metallic structure. Conventional CP systems resolve this problem by manual adjustment of DC voltage periodically to obtain a constant current. Such adjustment depends on the personal experience of the technician and the accuracy of the measuring equipment used. Accordingly, the adjustment is subject to personal and measuring equipment errors. Moreover, if the interval between two successive adjustments is relatively long, structure corrosion becomes significant, which may have drastic consequences. To overcome the aforementioned difficulties associated with the conventional CP system, an automatically regulated CP system is discussed in this article. The proposed system senses the variations of the surrounding medium resistivity and adjusts the DC voltage of the system automatically so that the DC current is kept constant at the required level. The design of a solar photovoltaic system to supply the CP system by the required DC power is also discussed.     

Modification of Exciton Lifetime by the Metal Cathode in Phosphorescent OLEDs,and Implications on Device Efficiency and Efficiency Roll‐off Behavior

Time resolved photoluminescence and electroluminescence measurements are used to study changes in the emission characteristics of materials typically used in phosphorescent organic light emitting devices (PhOLEDs). Studies on archetypical PhOLEDs with phosphorescent material, fac‐tris(2‐phenylpyridine) iridium (Ir(ppy)₃), show that the lifetime of triplet exciton is modified when in close proximity to a metal layer. Interactions with a metal layer ～30–100 nm away, as is typically the case in PhOLEDs, result in an increase in the spontaneous emission decay rate of triplet excitons, and causes the exciton lifetime to become shorter as the distance between the phosphorescent material and the metal becomes smaller. The phenomenon, possibly the result of the confined radiation field by the metal, affects device efficiency and efficiency roll‐off behavior. The results shed the light on phenomena affecting the efficiency behavior of PhOLEDs, and provide new insights for device design that can help enhance efficiency performance.     

A rechargeable battery of the type polyaniline/propylene carbonate-LiClO4/Li-Al

A secondary battery of the type polyaniline/propylene carbonate-LiClO₄/Li–Al is described. The polymer is made by aniline oxidation with ammonium persulphate in NH₄F, 2.3 HF as solvent. The discharge capacity of the polymer is 100 Ah kg^–1 at 25°C and 140 Ah kg^–1 at 40°C for current densities of 0.5 mA cm^–2 and for an amount of material giving a capacity of 10 mAh. The voltage in open circuit for the fully charged battery is 3.6 V. The average usable potential is 2.8–3 V. The energy density for the polymer lies between 280 and 420 Wh kg^–1. The ratio of the amounts of electricity in discharge and charge is one for several hundred deep cycles. The behaviour with regard to self discharge and to constant applied voltage (floating life) is excellent.     

Automated Linear System Parameter Identification Using Successive Differentiation and its Application in Microprocessor Controlled C and Tan ? Measurement

A new algorithm is suggested for linear system parameter identification, which lends itself easily to implementation using microprocessors. The main feature of this algorithm is that it is based on the estimation of the values of the successive derivatives of the input and output variables. This new algorithm was successfully used to measure unknown capacitances and inductances together with their loss angles using the TMS9980A microprocessor.     

Leakage flux saturation effects on the transient performance of wound-rotor induction motors

The prediction of induction machine performance has traditionally been based on the constant parameter models. This approach was later replaced by considering saturation in the main flux paths. However, such models have not been sufficiently accurate for certain transient conditions such as on-line starting and short-circuit. So, an accurate study of their performance should necessarily consider the magnetic saturation effect both in the main and leakage flux paths. In this paper, an experimental procedure to determine the machine parameters and saturation characteristics is adopted. The adopted experimental procedure facilitates the measurement of both stator and rotor leakage reactance saturation characteristics. Two models of saturated induction motors are developed to predict the transient performance of a laboratory wound-rotor induction motor. The results calculated by the proposed models considering and ignoring the leakage flux saturation are compared with the experimental results. The model that considers saturation in the leakage flux paths produces more accurate transient responses.     

Influences of Mn doping on the microstructural,semiconducting, and optoelectronic properties of HgO nanostructure films

Mn-doped HgO nanostructured thin films (Hg_1-xMn_xO) have been prepared using electron beam evaporation technique on Corning glass (1022) substrate at room temperature with different concentrations x = 0, 0.015, 0.05, 0.1, 0.15, and 0.2. The microstructural, morphological, semiconducting, and optoelectronic properties of the films have been investigated. The X-ray diffraction spectra suggest a hexagonal wurtzite type structure with lattice parameters decreased with increasing Mn content. It was found that the average particle size of the films decreases with increasing Mn doping which is confirmed by FE-SEM and AFM micrographs. The optical band gap of the investigated Mn-doped HgO nanocrystalline films is determined from the absorption coefficient and found to increase with the increase of Mn concentration which is attributed to the sp-d exchange interaction and/or the quantum confinement effect. The refractive index and extinction coefficient of the Mn-doped HgO films are also reported. The refractive index dispersion n(λ) is analyzed by single-effective-oscillator dispersion model proposed by the Wemple–DiDomenico (WDD). The oscillator parameters were estimated. The obtained dispersion values are suitable for the design of optoelectronic devices.     

Parameters extraction of PEMFC's model using manta rays foraging optimizer

In this article, a recently developed bio-inspired based manta rays foraging optimizer (MRFO) is attempted for reliable and accurate extraction of the model uncertain parameters of proton exchange membrane fuel cells (PEMFCs). The parameter estimation is formulated as a non-linear optimization problem subject to set of restrictions. The great development and tremendous revolution of computation heuristic-based algorithms are the impetus of the authors to apply the MRFO to solve this constrained optimization problem resulting in a precise PEMFC model. Three case studies of typical field PEMFC stacks namely Ballard type Mark V, NedStack type PS6, and Horizon type H-12. Various I to V datasets are demonstrated to appraise the performance of MRFO among other recent optimizers available in the literature. To be objective and for sake of quantifications, the best scores of minimum fitness values are 0.8533, 2.1360, and 0.0966 for the later said PEMFC stacks, correspondingly. At a later stage, production of various characteristics under varying operating conditions such as changeable cell temperature and regulating pressures are established using the generated best values of PEMFCs model. Further calculations of statistical indices are performed to validate the robustness of obtained results by the MRFO. Through comprehensive performance assessments, it can be confirmed that MRFO is very promising tool for the effective extraction of PEMFCs' model and suggested to be applied for solving other engineering problems.