It is found that mixture of 1,2,3 benzo triazole (BTAH) with polyethoxylated sorbitan monooleate, a non-ionic surface-active agent (NIS) effectively improves the properties of the cast concrete as well as significantly reduces the chloride induced corrosion of steel reinforced bars, when added in freshly prepared paste of mortar mixture. The addition of this mixture in the cast mortars is noted to reduce the water absorption in comparison to the control mortars cast using identical materials and under similar cast conditions. Electrochemical impedance spectroscopy and polarization studies of the rebars embedded in mortars and exposed in cement slurry have been performed to study the role of synergistic mixture on kinetics and mechanism of corrosion of rebars. The characterisation of corrosion products formed on the surface of rebars was carried out by X-ray diffraction, Scanning electron microscopy and EDX analysis. It is proposed that the synergistic boosting in protection is caused due to the shielding of NIS around anionic BTA-, thus minimizing their electrostatic repulsion. This facilitates the migration of additional ionic BTA towards the double layer which increases their concentration at the corroding interface leading to reduced susceptibility to corrosion.

X-ray diffraction (XRD), electrochemical tests, scanning electron microscopy and energy-dispersive X-ray analysis (SEM-EDXA) techniques were used to study the kinetics and growth of akageneite in corrosion products of steel exposed in moist soil added with chloride salts of sodium, potassium calcium, magnesium, and barium. The cations significantly affected the kinetics of corrosion and nucleation and growth of the akageneite. Divalent cations catalyze the corrosion and akageneite formation. The volume fraction of akageneite determined by XRD for monovalent cations (Na+ and K+) is observed in the range of 10–12

In this study, the efficacy of the combined effect of borate and silicate alkali metal salts added to mortars for controlling the chloride-induced uniform and localized corrosion of embedded steel rebars is examined. The individually added salts in mortars are found to have insignificant effects in terms of reducing the uniform corrosion rate and localized damage. However, their combination (0.50% sodium tetra borate + 0.10% sodium silicate added with respect to the weight of the binder) provides complete protection to reinforcements tested for long durations under wet/dry treatments with mortars in saline water and laboratory atmospheres. Electrochemical impedance spectroscopy, direct current cyclic polarization, polarization resistance, and visual observations are used for quantitative and qualitative evaluations of the protective effects of the tested additives. X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis of the corrosion products formed on the embedded steel surfaces help explain the possible mechanisms behind the considerable improvement in the inhibitive effects of a mixed composition of borate and silicate. This combination also improves the compressive strength and workability of the mixed concrete. The results reveal that the synergistic protection provided by a mixture of borate and silicate can be attributed to the co-deposition of an iron-boron + ferrosilicate + cortensitite (an iron-silicon phase) film on the rebar surface.

This research article presents a comparative analysis of two different heuristic optimization techniques for controller design of Automatic Generation Control (AGC) application. A conventional PID tunning method Ziegler-Nichols is compared with Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) heuristic optimizer. The output result is evaluated in terms of frequency deviation and tie-line power flow for undesirable load change. The performance of the controller is presented in a numerical format using standard IAE, ISE, ITAE, and ITSE performance indices.

Abstract This article presents a load flow analysis strategy for an operational active distribution feeder network. ETAP is used for load flow calculation while MATLAB is utilized for optimized operation of feeder components. Integration of wind and photovoltaic (PV) distribution generator is considered along with static compensator capacitor banks. The optimal operation of the feeder network is achieved by analyzing the feeder parameters such as total power loss, nodal voltage drop, and reactive power requirement. Static capacitor banks operation is optimized using feeder parameters. Under-load and over-load scenarios are executed and tested to achieve real-life operational scenario of diverse loading. Standard IEEE-33 bus feeder network is used for this study. A wide range of scenarios are performed in the case study and results are presented in both graphical and numerical format.

This communication reports the effect of phosphorus (P) added in micro concentration range in steel on kinetics, mechanism and growth of passive film in contact of chloride contaminated concrete. Electrochemical impedance spectroscopy, direct-current polarization, mass loss and Raman spectroscopic techniques were used to arrive at the findings. The results showed that an intentional addition of P in steel (0.064%) makes it more prone to uniform and localized corrosion (about 1.1 and 1.7 times) than the steel having low phosphorus (< 0.016%, present as tramp element) exposed under wet/dry conditions in simulated pore solution added with chloride and in the absence of this ion. A similar effect is also noted for the rebars embedded in mortars. Identification of corrosion products formed on steel rebars surface by Raman spectroscopy reveals thermodynamically stable maghemite and goethite phases on the surface of low P content steel. Unstable phase of lepidocrocite is recorded on the surface of higher phosphorus steel rebars. The findings are discussed with experimental evidence and taking clues from the published literature to arrive at plausible mechanism for this behaviour.

This paper presents the impact of distributed generation (DG) integration on the voltage profile of the radial distribution network. The impact with the integration of the DG is analyzed using a modified power flow technique. The power flow analysis of the passive distribution network is done using the backward-forward sweep method. A novel constant power voltage (PV) DG integration technique is used to simulate real-life power by controlled DGs. This technique is added in the backward-forward sweep method and a modified power flow technique is proposed to reflect the DG integration impact. Simulation is carried out on, 15-bus and 85-bus systems to demonstrate the impact of DGs integration. The voltage profiles are obtained with and without DG integration and results are presented in graphical form.

Deterioration of metallic and non-metallic structures and monuments is largely controlled by their surrounding environment. The Taj Mahal, a UNESCO (United Nations Educational, Scientific and Cultural Organization) world heritage situated in Agra of India built in seventeenth century using white marbles, is famous for its aesthetic look. Gradual yellowing and blackening of the monument are matter of great concern, and if not controlled, the heritage structure may lose its glaze and beauty. Extensive studies available on deteriorating effect of the monument miss a vital point related to the pollutants coming from severely polluted River Yamuna which flows very close to the Taj Mahal. To ascertain the possible effects of the pollutants carbon steel, copper and zinc samples were exposed for four years at the premise of Taj Mahal. The surface characterization of the exposed metals with electrochemical impedance spectroscopy, Raman spectroscopy and X-ray diffraction reveals the formation of respective sulphides of the studied metals. The findings suggest that the hydrogen sulphide from the polluted Yamuna River had damaging effect. The wind rose diagram developed at site of exposure further supports the above findings. The corrosion rate of copper was found to be 2.46 µm/year. This observation as well as identification of corrosion products formed on the metal surface (strong peaks of copper sulphide) provided strong evidences that the hydrogen sulphide evolved from the polluted river accelerated the deterioration of the metal.

This paper presents the impact of energy storage on the responses of two-area thermal power systems connected via a tie-line. Improving system parameters such as frequency deviation and tie-line power deviation are key objectives of the analysis. Controller parameters are optimized by genetic algorithm (GA) technique. An enhanced Fuzzy-PID controller is proposed, which delivers better response compared to conventional Integral and PID controllers. In this study energy storage devices such as superconducting magnetic energy storage (SMES) and capacitor energy source (CES) are utilized as tertiary control mechanisms to improve system responses. A detailed comparative analysis is performed for energy storage devices as well as for controllers.

The power system operation needs to keep the harmony among the power generation and demand, failing which will leads to sudden rise and fall of frequency as well as transient tie-line power. AGC is one of the significant control phenomenon in power system, for control of frequency and power in an interconnected system. This paper presents the details of issues related with specific controlling techniques used in AGC at the past and with what control we can rectify those issues in future. This paper also presents a brief review of the controlling methods that has been exercised to automatic generation control (AGC) from the primeval time to the modern day. Review related to literature work of AGC in deregulated environment has been presented.

Corrosion resistance performance of rebars rolled from vanadium micro-alloyed (VMA) steel was evaluated vis-à-vis rebars rolled from steel having similar chemistry to the (VMA) steel without vanadium and subjected to thermomechanical treatment after hot rolling (TMT). Three test environments namely simulated concrete pore solution, mortars, and industrially polluted atmosphere were used to assess the performance of these rebars. Mass loss, electrochemical impedance spectroscopy, DC polarization and potential-time studies were employed to acquire quantitative data and explain the observed results. Raman spectroscopy was used to identify the corrosion products formed on the surface of the exposed rebars in different environments. The corrosion resistance of VMA rebars was better than TMT especially with increased duration of exposure in chloride contaminated concrete environments. However, under the industrially polluted atmosphere, both rebars exhibited comparative corrosion rates. Lesser detrimental effect of chloride present in concrete environment on the VMA steel rebars is attributed to the higher grain boundary per unit area in these rebars than in the TMT rebars. It is suggested that owing to the stronger tendency of the higher-grain-boundary- material to interact with oxygen and moisture, a thicker film of Fe(OH)3 was formed on its surface than on the surface of the TMT rebar, prior to their exposure to the test environments. This hydroxide film dissolved in alkaline environment of concrete, nucleated and grew as a protective FeOOH film on the surface of the rebars.

Role of alloying of lead in hot dip galvanized coating deposited on mild steel wire on their corrosion characteristics are studied exposing them in industrial, coastal urban environments and laboratory simulated electrolytes. Various corrosion evaluation techniques namely mass loss, electrochemical impedance spectroscopy and direct current polarization methods are used to assess corrosion characteristics of the wires. Corrosion products formed on the exposed samples and cross section of the coatings are analyzed by X-Ray Diffraction, Raman Spectroscope and Scanning Electron Microscope. Lead is observed to change the corrosion characteristics of the coatings with change in constituents of the environments. In saline electrolytes, alloying of lead is found to accelerate the corrosion rate. This metal deposits as cluster on top layer of the galvanized coatings and acts as strong cathodes with respect to the zinc and accelerates the corrosion rate. In sulfurous environments, a stifling effect on rate of corrosion is noted which is attributed to the formation of stable and moisture insoluble sulfate compounds of lead on the surface of the coating.

In this investigation zinc was alloyed with aluminum in order to improve the corrosion resistance of hot-dip galvanized coated steel rebars in contact with chloride-contaminated concrete. To rapidly assess the role of aluminum alloying in zinc, test panels in sheet form containing 10%, 15%, 20%, and 30% aluminum in zinc were prepared and evaluated in terms of their corrosion resistance via salt spray exposure tests. It was found that 10%Al-90%Zn (10AZ) provided the best results. Mild steel rebars were galvanized in 90% Zn-10%Al and 100%Zn (100Z) baths and their corrosion resistance performances when they were exposed to simulated concrete pore solution and embedded in mortars were examined. The10AZ-coated rebar showed superior corrosion resistance performance to the 100Z-coated rebar. Electrochemical impedance spectroscopy, DC polarization, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques were used to study the kinetics and corrosion mechanism of the coated rebars. (C) 2020 Elsevier Ltd. All rights reserved.

No single metaheuristic search algorithm can be adjudged universally best general-purpose optimizer. The performance of search algorithms mainly depends upon the weightage assigned to global and local search strategies. This paper proposed an improved directional bat optimizer to minimize the operating cost of the electric power dispatch (EPD) problem that establishes a balance between global and local search strategies. Improved directional bat algorithm exploits directional echolocation bat behavior, directional exploration, neighborhood search and opposition based learning for generation jumping. The directional bat algorithm acts as a global search tool whereas exploration in each direction and neighborhood search performs local search. Opposition learning improves convergence with diversity. An effect of valve-point loading introduces a discontinuity in cost characteristics. The EPD problem addresses energy balance, generator capacity, ramp-rate limits and prohibited operating zones (POZ) avoidance constraints. An iterative technique handles energy balance constraint. The generation is adjusted to avoid the violation of generation capacity, ramp-rate limit and POZ constraints. The proposed algorithm is verified on various electric power systems. The results verify that the proposed algorithm is a potential algorithm to solve EPD problems as it competes with recent existing algorithms undertaken for comparison

Owing to no free lunch theorem, meta-heuristic search algorithms, behaviour and performance are different for solving specific class of optimization problems than another. Further, search algorithms are conceptualized of exploration and exploitation aspects. Ameliorated grey wolf optimization algorithm is proposed to solve economic power load dispatch problem that synergizes between exploration and exploitation aspects. Ameliorated grey wolf optimization procedure coordinates the behaviour of grey wolves, random exploratory search, local random search and opposition learning heuristics. Grey wolf optimization algorithm is considered to perform global search and random exploratory search applied to perform a search in the neighbourhood of already visited search locations. To maintain good solutions and diversity among solutions, opposition based learning has been implemented. The practical aspects i.e. value-point loading effect, avoidance of prohibited operating zones and ramp rate limits, generation limits of generators and satisfaction of power demand constraint are undertaken to solve economic power load dispatch problem. Heuristic search is exploited to handle equality constraints. The proposed algorithm is validated on standard benchmark functions and medium to large electric power systems. Results reveal that proposed technique is a potential method to solve economic load dispatch problems as it competes with recent algorithms undertaken for comparison.

Even though publications on discussed cash flow inventory problem are steadily growing, modelling the manager's characteristics and their effect on his/her decisions and planning outcome has not attracted in the text. In order to fill this gap and model authenticity more precisely. This research work develops a new economic order quantity (EOQ) model using discounted cash flow (DCF) approach under multiple suppliers' trade credits with stock-linked demand for failing commodities. This paper is a generalisation of an offered inventory model with trade credits in which both demand and deterioration are stable. Here the assumption of constant demand relaxed by incorporating the idea of learning in stock-dependent demand using DCF approach. The projected inventory control model using DCF approach and learning in multiple suppliers' trade credit has most excellent presentation in competence. Mathematical formulation is provided for three different situations for finding optimal cycle time and all future cash flows. On the basis of optimal solution some useful results are also discussed. Numerical examples are provided to demonstrate the models proposed in this study. Sensitivity analysis is also presented dissimilar parameters.

Use of thermomechanically treated (TMT) reinforcing bars has become popular in the concrete construction industry after their introduction in the 1980s. This can be attributed to the fact that thermomechanical treatment enhances the strength and ductility of reinforcing bars remarkably. However; limited research is available on the corrosion behavior of TMT reinforcing bars after they are embedded in concrete. To enhance knowledge and insights into this area, the authors investigated the protective properties of two types of steel reinforcement bars (reinforcing bars)-namely tempered martensite (TM) and pearlite-ferrite (PF)-after exposing them to concrete pore solution. The microstructures of both types of reinforcing bars were investigated, and their kinetics of growth and mechanism of nucleation were recorded by employing electrochemical impedance spectroscopy and polarization. Studies reveal that protective film on the surface of steel with TM microstructure develops at a significantly higher rate and is more stable compared to that on steel with PF microstructure. This superior protective nature is attributed to the development of a compact and adherent oxide film on TM steel. A model is proposed to explain the results obtained during the study. Raman spectroscopy of passive films formed on the surface of reinforcing bars exposed to concrete pore solution supports the proposed model.

The protective properties of a newly developed phosphoric acid based rust converter are investigated for reinforcement corrosion under chloride-contaminated concrete environment. The electrochemical evaluation of specimens after 6 years (2 years of wet-dry exposure in 3.5% sodium chloride solution and 4 years in dry laboratory environment) demonstrated that treating the reinforcing bar with the newly developed product significantly reduced the corrosion rate compared to the control reinforcing bar. Based on the results of Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy, a new mechanism is described for the transformation of unstable rust phases into stable phases. It is observed that iron phosphate remains entrapped with corrosion products formed on the surface of the treated steel reinforcing bar, even after 6 years of exposure.

Rationale: Fractures of femoral head associated with a hip dislocation are relatively rare and often associated with a poor functional outcome. Fractures are characterised by a high risk of avascular necrosis of femoral head, is extremely rare. It is more difficult to treat and has a worse prognosis. Patient concerns: A 18 year old male with history of sustained injury over his left hip due to jump from running tractor that turned turtle. Pelvic radiograph and 3-D reconstruction computed tomography revealed characteristics of fracture dislocation of femoral head before the elective operation.Diagnosis: Pipkin type II fracture dislocation of femur head. Interventions: Firstly, dislocation was corrected by closed manual reduction under anesthesia. Secondly we used lateral approach to fix the femoral head fracture. Then we completed anatomical reduction of fractures with countersunk head screw. Outcomes: At 4 months follow up the patient could walk and perform activities of daily living without pain, limp, signs of necrosis of femoral head and heterotopic ossification. Conclusion: Treatment aim should always be the anatomical reduction of fragments with minimal soft tissue injury. Sometimes closed reduction is enough, but in the presence of large fragments, the fracture-dislocation is better treated by ORIF. We should not forget that half of these patients will have good outcomes no matter the treatment strategy. This result depends upon general health of the patient, the severity of the injury, associated cartilage injury, and timing of admission to hospital. Lessons: Although there are serious complications in Pipkin II fractures early surgical treatment with appropriate approach and fixation could get satisfactory results.

Fracture dislocations of the proximal humerus are extremely rare and have poor functional and radiological outcome regardless of many available surgical interventions. We present two such cases where a post traumatic complex fracture dislocations managed by contrasting surgical interventions. Two cases presenting to our institution aged 32 and 58 years managed surgically are reported in this study. The surgical intervention and the implant chosen was with respect to their age and socio-economic status of the patients, which has resulted in a cost effective radiological outcome.