Facile Fabrication of Nano-sized SiO2 by an Improved Sol–Gel Route: As an Adsorbent for Enhanced Removal of Cd(II) and Pb(II) Ions

Journal of Inorganic and Organometallic Polymers and Materials - We herein report a direct and facil sol–gel method for the preparation of porous silicon dioxide nanoparticles using dissolved...     

Iterative Clustering for Energy-Efficient Large-Scale Tracking Systems

Wireless Personal Communications - A new technique is presented to design energy-efficient large-scale tracking systems based on mobile clustering. The new technique optimizes the formation of...     

Deer Hunting Optimization with Deep Learning Model for Lung Cancer Classification

Lung cancer is the main cause of cancer related death owing to its destructive nature and postponed detection at advanced stages. Early recognition of lung cancer is essential to increase the survival rate of persons and it remains a crucial problem in the healthcare sector. Computer aided diagnosis (CAD) models can be designed to effectually identify and classify the existence of lung cancer using medical images. The recently developed deep learning (DL) models find a way for accurate lung nodule classification process. Therefore, this article presents a deer hunting optimization with deep convolutional neural network for lung cancer detection and classification (DHODCNN-LCC) model. The proposed DHODCNN-LCC technique initially undergoes pre-processing in two stages namely contrast enhancement and noise removal. Besides, the features extraction process on the pre-processed images takes place using the Nadam optimizer with RefineDet model. In addition, denoising stacked autoencoder (DSAE) model is employed for lung nodule classification. Finally, the deer hunting optimization algorithm (DHOA) is utilized for optimal hyper parameter tuning of the DSAE model and thereby results in improved classification performance. The experimental validation of the DHODCNN-LCC technique was implemented against benchmark dataset and the outcomes are assessed under various aspects. The experimental outcomes reported the superior outcomes of the DHODCNN-LCC technique over the recent approaches with respect to distinct measures.     

Effective damping of local low frequency oscillations in power systems integrated with bulk PV generation

High penetration of renewable sources into conventional power systems results in reduction of system inertia and noticeable low-frequency oscillations (LFOs) in the rotor speed of synchronous generators. In this paper, we propose effective damping of LFOs by incorporating a supplementary damping controller with a photovoltaic (PV) generating station, where the parameters of this controller are coordinated optimally with those of a power system stabilizer (PSS). The proposed method is applied to damp local electromechanical modes by studying a system comprising a synchronous generator and a PV station connected to an infinite bus. The PV station is modeled following the instructions of the Western Electricity Coordinating Council. The problem is modeled as an optimization problem, where the damping ratio of the electromechanical modes is designed as the objective function. Constraints including upper and lower limits of decision parameters and damping ratio of other modes are considered by imposing penalties on the objective function. Different optimization algorithms are used to pursue the optimal design, such as political, improved gray wolves and equilibrium optimizers. The results validate the effectiveness of the proposed controller with PSS in damping local modes of oscillations.     

Microwave‐Assisted Synthesis of Magnetic Hydroxyapatite for Removal of Heavy Metals from Groundwater

A simple, fast, and economic methodology to fabricate a highly efficient superparamagnetic Fe₃O₄/hydroxyapatite nanocomposite (MHAP) was successfully developed. Hydroxyapatite was functionalized with magnetite nanoparticles through coprecipitation‐assisted microwave processes to improve the magnetic properties. The synthesized magnetic hybrid adsorbent matrix was investigated by different methods. Transmission electron microscopy demonstrated a good impregnation of Fe₃O₄ on the hydroxyapatite matrix with uniform morphology. Magnetic hysteresis measurement revealed that MHAP nanocomposites exhibit excellent strong, soft‐magnetic properties. The synergistic effect was an evidence for iron and manganese ion removal, enlightening their potentialities in treatment of polluted ground water.     

MoO3—Fe2O3 catalysts: Characterization and activity for isopropyl alcohol decomposition

The vapour-phase dehydration and dehydrogenation of isopropyl alcohol (IPA) have been carried out over pure MoO₃ and Fe₂O₃, produced by calcination of ammonium heptamolybdate and of iron (III) nitrate respectively, as well as MoO₃ mixed with 0·5 and 50 mol% Fe₂O₃, prepared from the same materials. All catalysts were calcined in air, in the temperature range 200–600°C for 5 h, and were characterized by thermal analysis (TG, DTA), XRD, IR and S_BET. Surface areas decreased with increasing calcination temperature, and the catalytic activity of the pure oxides MoO₃ and Fe₂O₃, as well as of MoO₃–0.5 mol % Fe₂O₃, increased with their S_BET. The activity of MoO₃–50 mol % Fe₂O₃, which was independent of its S_BET, could be attributed to the increased intensity of terminal Mo—O bonds as shown by IR spectra. The activation energies for the decomposition of IPA over catalysts calcined at 250 and 500°C are tabulated.     

Interaction between inclined pile groups subjected to harmonic vibrations

Vertical and inclined piles are used in seismic areas where they could be subjected to oblique harmonic vibration loads. The effect of closely spaced battered piles on the pile–soil–pile interaction has not yet been fully recognized. A simple analytical method, based on the elasto-dynamic theory by Novak and his associates, is used in the present study to characterize vertical and inclined isolated cylindrical piles subjected to inclined harmonic vibrations. The free field movement of the ground in the vicinity of the piles is determined using an approximate approach based on the interference of the cylindrical wave field originating along each pile shaft and spreading radially outward. In calculating the interaction factor between two battered piles, an analysis has been carried out to demonstrate the effect of the presence of a neighboring pile (receiver) while the first pile (source) is loaded. In this situation, it has been found that the movement of the source pile head is decreased when a receiver pile is present. Also, the effects of the pile–pile distance, the group geometry, the length of the piles, and the inclined angle for each or all of the piles have been studied and the corresponding results will be presented.     

Experimental analysis of energy recovery for humidity control in split A/C system

This study presents a proposed idea about making use of the thermal energy rejected by the condenser in a water-cooled split-air-conditioning systems to decrease the relative humidity of the cold air supplied by such air conditioners. Most of split air-conditioner systems cool air without controlling its humidity. An amount of heat is rejected from the air conditioner, through the condenser, into the surrounding in order to allow the refrigerant to cool down and condense, thus, part of the lost energy can be exploited to decrease the relative humidity of the sub-cooled air that leaves the evaporator as saturated humid air. Four variables, viz. the coil type (single or double), the amount of flowing water, water, temperature, and the cooled air velocity were studied to find out the optimum conditions required for this purpose. The requisite amount of heat that may adjust the relative humidity of the conditioned air was also determined. The experimental results suggest an optimum design of a heat exchanger for performing the use of the heat rejected from the condenser to achieve the aim. As a result, the proposed heat recovery concept can be worthily adopted to achieve economic results in large-scale systems.     

Hyperphosphatemia among end‐stage renal disease patients in developing countries: A forgotten issue?

The prevalence of hyperphosphatemia and increased calcium-phosphorus product has never been evaluated in a large multicenter study in a developing country. Our aim is to study the prevalence of hyperphosphatemia in 38 HD centers in Egypt (as an example of a developing country) and to correlate it with different co-morbid conditions and the patient's demographic data. This is a cross-sectional study conducted on 1005 chronic kidney disease stage 5 patients (CKD-stage 5) on HD for a period of more than 1 year in 38 dialysis centers in Egypt. All patients were receiving calcium-based salts as a phosphate binder. Hyperphosphatemia and increased calcium-phosphorus product were evaluated and correlated with different parameters including age, sex, knowledge by diet parameters, HD session duration, the frequency of HD per week, the type of dialysis membrane, the surface area of the dialyzer, dialyzer phosphorus clearance (phosphorus KoA), and the type of dialysate. Other co-morbid medical conditions and evidence of IHD were also investigated. Hyperphosphatemia was present in 69.1% of cases and a high calcium-phosphorus product was present in 30.2%. A higher calcium-phosphorus product was found among males. 83.2% of those with a poor knowledge by diet parameters had hyperphosphatemia compared with 67.6% in patients with a satisfactory knowledge by diet parameters. 72.3% of patients using a membrane with low-to-medium clearance had hyperphosphatemia, compared with 67.2% using a membrane with a high clearance. Seventy-two percent of patients with IHD were hyperphosphatemic compared with 67.6% of the non-ischemic patients. Hyperphosphatemia is a major problem in dialysis patients in developing countries, reflecting differences from developed countries regarding dietary habits, ethnic factors, dialysis quality, types of dialysis membranes, as well as economic factors hampering the use of the more expensive phosphate binders. Extended dialysis hours may be a good alternative solution in developing countries.     

Constitutive Model for Time-Dependent Behavior of FRP–Concrete Interface

A fundamental understanding of fiber-reinforced polymer (FRP) laminate bonding behavior, including bond strength and effective bonding length, is of primary importance for the development of design guidelines and codes for concrete structures strengthened with externally bonded FRP reinforcement as a bond-critical application. However, the long-term serviceability of such FRP-strengthened structures is still a concern due to a lack of both long-term performance data and a suitable model to represent these performances. This study aims at presenting a viscoelastic model describing the time-dependent behavior of the FRP–concrete interface. The proposed model has been calibrated using strain measurements of the designed specimen for the experimental investigation of the time-dependent behavior of the FRP–concrete interface, including the development of the effective bonding length. Afterward, the proposed model satisfactorily predicts the time-dependent bonding length of the FRP sheet in comparison with the experimental results. The effects, both of creep of the adhesive layer and of creep and shrinkage of the concrete, on the changes in the effective bonding length of the PFRP sheet are also discussed.