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Electroencephalography (EEG) signals are usually affected by presence of missing data because of various reasons. Depending on the percentage of missing data, it affects significantly the classification accuracy which in turn affects the performance of prosthesis. Moreover, it has also been observed that there exists no universal classifier which performs best in all types of data. Therefore, in this paper, we propose a framework to employ tensor-based Canonical/Polyadiac Weighted-optmization (CP-WOPT) and Artificial Neural Network (ANN) to recover missing data and perform classification, respectively. The results of classification have been compared with established methods such as Linear Discriminant Analysis (LDA), Support Vector Machines (SVM), Logistic regression, Boosted trees, Bagged trees and k-nearest neighbor (kNN). The results indicate significant improvement in classification accuracy on complete, missing and recovered data when ANN is employed. Classifiers are applied on complete, missing and recovered data explicitly to test the performance of our framework. Results show that mean classification accuracy on complete data, missing data and recovered data was 88%, 62% and 81% respectively which shows applicability of our framework.

This paper reviews the thermophysical properties of saline water correlations and data. The key parameters that influence the properties are considered, such as multi-component composition, high salinity, temperature, and pressure. Since the thermodynamic properties are reviewed in part I of the paper, this part (# II) focuses on the thermophysical properties involving viscosity, surface tension, electrical conductivity, thermal conductivity, osmotic coefficient, activity coefficient, and thermal expansivity. The properties are comprehensive to include all saline water types, i.e., brackish water, seawater, high saline water from basins, lakes, produced water from oil and gas hydraulic fracturing, and so on. The correlations are summarized in tabular forms and assessed based on their accuracy against available experimental data. Besides, guidelines for choosing some correlations are also discussed. Since the thermal conductivity has no multi-component model, a novel and straightforward model is proposed with excellent accuracy.

The concept of non-uniform heat flux distributions has emerged because of its potential to make the design of thermal systems more flexible. Therefore, the current study highlights the impact of non-uniform heat flux distributions on the thermal characteristics of a high Prandtl number fluid for forced convective laminar flow regime in a horizontal pipe. The steady-state 2-D simulations have been employed using ANSYS Fluent. The variations in heat flux distributions as a wall boundary condition are systematically analyzed while keeping the total heat transfer constant. The results obtained for various distributions are compared in terms of a dimensionless maximum wall temperature (hot spot), local and average Nusselt numbers, and entropy generation rate. The analysis showed that the heat flux distributions significantly affected the heat transfer pattern. It was found that the hot spot temperature was lower for the descending heat flux boundary conditions compared to the ascending type of distributions. However, a higher entropy generation rate was observed for descending distributions as compared to ascending ones. It was also found that the ascending heat flux distributions provided higher average Nusselt number values than the descending cases of heat flux.

Heat exchangers are used to transfer energy from one medium to another and increase contact area for higher efficiency. In case of fluids, higher flow area would lead to high/low flow zones that severely affect the fluid dynamics and thermal performance. Channels are used to distribute the flow uniformly to fully utilize the whole heat exchanger area. The flow uniformity in a flow distribution manifold is dependent on several factors such as flow rate, inlet and exit locations, and the manifold and channel geometrical configuration. In the current work, flow distribution measurements were performed using a particle image velocimetry (PIV) technique in two types of rectangular manifolds. The experimental results are further verified against the results obtained from numerical modeling with similar trends. The flow distribution in U- and Z-type arrangements are evaluated and compared with ten channels incorporated in the design. It was found that the flow is more in the channels near the inlet for U-type design, while more near the outlet for the Z-type. An increase in the inlet flow rate enhances the flow distribution for the U-type while results in more maldistribution for the Z-type. For the U-type, the normalized velocity varies from 1.34 to 0.52 in a wide manifold, and between 2.82 and 0.18 for a narrow manifold. A U-type wider manifold is recommended for all conditions examined in this work since at lower flow rates, both have similar mirrored distribution, while at higher flow rates, U-type manifold has better flow distribution.

Performance is analyzed for kinetic energy variation in high velocity stream heat exchangers that are subjected to external heat transfer. Analytical solutions are obtained using the method of inverse operators. They are verified against the reported expressions in the appropriate limits for constant kinetic energy system as well as for perfectly insulated conditions. Kinetic energy decay in hot stream enhances performance that exceeds the conventional heat exchanger effectiveness. For kinetic-to-thermal energy ratio and dimensionless characteristic length constant each equaling unity on the hot side, the terminal effectiveness under balanced operation is 136% for counter-flow arrangement and 82% for parallel-flow in the absence of external heat load. On the contrary, decay on the cold side lowers performance. For unbalanced flow, kinetic energy change in the higher heat capacity rate fluid has a lesser impact on the effectiveness. Thermal interaction with the ambient generally has a deleterious effect on the hot stream effectiveness of the cryogenic system. However, the performance improves under certain conditions such that the rise in fluid temperature caused by kinetic energy deterioration promotes heat loss to the surroundings.

This study investigates the performance of a novel humidification dehumidification (HDH) desalination system integrated into a vapor compression (VC) heat pump. The integrated heat pump delivers th...

For non-axisymmetric conditions, the traditional fluid mean (bulk) temperature at a tube cross section, subjected to constant heat flux, can be higher than the temperature of a point on the wall. T...

Fast and effective recommender systems are fundamental to fulfill the growing requirements of the e-commerce industry. The strength of matrix factorization procedure based on stochastic gradient descent (SGD) algorithm is exploited widely to solve the recommender system problem. Modern computing paradigms are designed by utilizing the concept of fractional gradient in standard SGD and outperform the standard counterpart. The performance of fractional SGD improves considerably by adaptively tuning the learning rate parameter. A nonlinear computing paradigm based on normalized version of fractional SGD is developed in this paper to investigate the adaptive behavior of learning rate with novel application to recommender systems. The accuracy of the proposed approach is verified through root mean square error metric by using different latent features, learning rates, fractional orders and datasets. The superiority of the designed method is validated through comparison with the state-of-the-art counterparts.

Shell-and-tube heat exchangers are frequently used in several industrial applications. A model was developed using engineering equations solver software to predict the performance of variou...

This paper introduces a novel humidification-dehumidification (HDH) system coupled with adsorption desalination (AD) system to produce freshwater as well as to obtain chilled water for an air-conditioning purpose. Two hybrid HDH-AD schemes are proposed in which the condenser of the AD system replaces the HDH heater. The difference is that the HDH inlet seawater is precooled in the AD evaporator before feeding the HDH system in Scheme # 1, while in Scheme # 2 the seawater is used to cool the adsorption process. Seawater mass flowrate and temperature, heating source mass flowrate and temperature, cycling time, and HDH mass flowrate ratio are the key parameters investigated to influence the hybrid system performance. The results exhibit that the gained output ratio (GOR) and cost values are higher in Scheme #1 (about 7.8 and 0.64 ¢/Liter, respectively). Scheme # 2 achieves an excellent GOR and cost values (about 7.6 and 0.65 ¢/Liter) with a cooling effect as a by-product (coefficient of performance (COP) is >0.45 under the same conditions of optimal GOR value). For the hybrid HDH-AD system, the HDH contribution in the total performance is vital while AD system can be used to control the HDH operating conditions.

Reverse osmosis is becoming popular for the purification of water resources e.g. sea and brackish water. However, one of the major limitations in efficient operation are the fouling of membranes and relevant technique used to inhibit scaling due to the presence of sparingly soluble salts. The occurrence of this type of fouling results in a significant increase in both operation and maintenance. This review begins by providing a general overview of membrane fouling by minerals usually found in sea and inland water resources. The paper then discusses some important aspects of the phenomena itself: different mechanisms; concentration polarization; the major types of mineral scales including their prevalence and characteristics; and consequences of fouling on membrane performance. This is followed by a discussion of the major strategies currently considered for the control and prevention of scale formation. The penultimate section discusses the drawbacks and deficiencies of current systems in operation and highlights potential future directions that need to be pursued in order to achieve overall process improvements in terms of sustainability. In particular, the need for evaluation under more realistic conditions, studying the interactions between membrane and spacer surface and foulants, and the development of environmentally benign antiscalants are stressed.

The performance of photovoltaic modules is adversely affected by an increase in photovoltaic cell temperature. Cooling of panels may lead to temperature non-uniformity in the photovoltaic panel, thus limiting the maximum efficiency of the cooled photovoltaic panel. In the current work, the design of a novel heat exchanger that can be used for uniform cooling of photovoltaic modules is presented. For this purpose, a computational fluid dynamics model has been set up. Using the model, the effects of various heat exchanger design parameters (like channel numbers, manifold width, the location of inlet/exit ports, and tapered channels) on its performance are sequentially analyzed resulting in fourteen designs. The performance is quantified by three parameters: top surface average temperature, temperature non-uniformity for photovoltaic module cooling quality, and the heat transfer per unit pumping power. The resulting optimized design is found to be a novel V-shaped heat exchanger design for the photovoltaic module cooling. It has a lower average temperature and temperature non-uniformity, smaller hotspots, and lower pumping power. The optimal design is further examined using experimental particle image velocimetry measurements.

This paper evaluates an optimal airside thermal-hydraulic performance of compact heat exchangers. Seventy-five airside surfaces have been chosen, i.e. standard reference of Kays and London, to represent louver-fin, strip-fin, wavy-fin, plain-fin, pin-fin, finned circular tubes and finned flat tubes. A robust evaluation method is implemented by an estimation of the heat transfer rate per unit pumping power with and without considering the heat exchanger compactness. Experimental data of Colburn j-factor and Fanning friction factor (f) are used to estimate both the heat transfer rates and the friction power, respectively. The results demonstrate that strip-fin surface 1/10-27.03 shows an optimal heat transfer values per unit friction power when the compactness is taken into consideration. Nonetheless, pin-fin surface PF-4(F) shows an optimal heat transfer rate per pumping power when neglecting the importance of the compactness. The geometries having an optimal thermal-hydraulic performance for each airside type (with or without considering the compactness) are recommended as benchmarks to assess the performance of similar airside surfaces.

The trend of applying mathematical foundations of fractional calculus to solve problems arising in nonlinear sciences, is an emerging area of research with growing interest especially in communication, signal analysis and control. In the present study, normalized fractional adaptive strategies are exploited for automatic tuning of the step size parameter in nonlinear system identification based on Hammerstein model. The brilliance of the methodology is verified by mean of viable estimation of electrically stimulated muscle model used in rehabilitation of paralyzed muscles. The dominance of the schemes is established by comparing the results with standard counterparts in case of different noise levels and fractional order variations. The results of the statistical analyses for sufficient independent runs in terms of Nash-Sutcliffe efficiency, variance account for and mean square error metrics validated the consistent accuracy and reliability of the proposed methods. The proposed exploitation of fractional calculus concepts makes a firm branch of nonlinear investigation in arbitrary order gradient-based optimization schemes.

This work focuses on proposing generalized air-side thermal-hydraulic correlations for wavy-fin compact heat exchangers. The new correlations are modeled from experimental and numerical f- and j-factor data reported in the literature and presented in this paper. We have simulated twenty-one new geometries, using experimentally validated three-dimensional model implemented in ANSYS Fluent program, to obtain heat-transfer and fluid-flow characteristics of unreported geometries. Data of 50 geometries are used to propose new f and j correlations with an rms error of 9.23% and 9.90%, respectively. Testing and comparing the present correlations with those reported in the literature demonstrate that the present air-side f- and j-factor correlations are more accurate and generalized for regular wavy-fin compact heat exchangers.

While representing a class of signals in term of sparsifying transform, it is better to use a adapted learned dictionary instead of using a predefined dictionary as proposed in the recent literature. With this improved method, one can represent the sparsest representation for the given set of signals. In order to ease the approximation, atoms of the learned dictionary can further be grouped together to make blocks inside the dictionary that act as a union of small number of subspaces. The block structure of a dictionary can be learned by exploiting the latent structure of the desired signals. Such type of block dictionary leads to block sparse representation of the given signals which can be good for reconstruction of the medical images. In this article, we suggest a framework for MRI reconstruction based upon block sparsifying transform (dictionary). Our technique develops automatic detection of underlying block structure of MR images given maximum block sizes. This is done by iteratively alternating between updating the block structure of the sparsifying transform (dictionary) and block-sparse representation of the MR images. Empirically it is shown that block-sparse representation performs better for recovery of the given MR image with minimum errors.

In this work, the fabrication and characterization of a dual-purpose membrane is reported: (i) oil-water separation with high efficiency, and (ii) effective and rapid photocatalytic degradation of hazardous environmental pollutants. Nanoparticles of a rare-earth oxide, cerium (IV) oxide, synthesized by a simple co-precipitation technique, were spray-coated onto stainless steel membranes to obtain a uniform coating with superwetting characteristics. The as-synthesized cerium (IV) oxide nanoparticles and its spray-coated stainless steel membrane were characterized by advanced analytical techniques. X-ray diffraction, selected area electron diffraction, and electron microscopy results of the cerium oxide particles showed a high degree of crystallinity and uniform particle size of ∼50 nm. Elemental surface analysis using X-ray photoelectron spectroscopy showed the characteristic peaks for Ce4+, thereby confirming the presence of cerium oxide nanoparticles. Contact angle measurements showed the coated membranes to be superhydrophobic (∼150°) and superoleophilic (∼0°). When used in a simple laboratory setup, the membranes were able to separate oil and water with a high efficiency (∼99%). Furthermore, the coated membrane showed enhanced photocatalytic activity under UV light irradiation resulting in the rapid degradation of organic persistent pollutants like MB dye in water. To summarize, this work presents an innovative approach in the application of multifunctional membranes for effective water treatment.

An optimal assessment of heat transfer and friction power performance is investigated to address a robust method for facilitating performance evaluation of different wavy-fin arrangements. Two benchmark geometries are presented to compare the performance of all the reported wavy-fin arrangements with and without considering heat exchanger compactness. New 21 wavy-fin geometries are numerically studied to represent the unreported arrangements in the literature. The performance results of 105 geometries showed that the reference standard geometries of Kays and London could be used as benchmarks to evaluate the airside arrangements, with and without considering the compactness effect, respectively. Heat transfers versus friction power plots are found to be a useful approach for performance evaluation purpose. The surface GK2 is found to have the optimal thermal-hydraulic performance when comparing the heat exchanger compactness, whereas GI1 and GK1 might represent the geometries having optimal performances when neglecting the compactness importance.

In this work, we report the preparation of superhydrophobic and superoleophilic surfaces on stainless steel meshes by spray-coating of Cerium(IV) oxide (CeO2) nanoparticles obtained by a co-precipitation method. The synthesized particles and the coated meshes were characterized using advanced techniques. Scanning electron microscopy images showed the particles to be present in distinct lumps; merged with each other on calcination to give a homogeneous structure. Transmission electron microscopy analyses showed the agglomeration of individual particles to form the clusters. Contact angle measurements revealed the superhydrophobic and superoleophilic nature of the modified mesh surface in air. Fourier transform infra-red analyses of the synthesized particles showed the characteristics peaks of CeO2 found in commercial samples. X-ray photoelectron spectroscopy of the glass coated with ceria confirmed the predominant presence of Ce4+ that also explained the wetting behavior. Oil-water separation studies using a simple gravity-driven setup showed high separation efficiency of an oil water mixture. An analytical model is discussed in detail to account for the wetting behavior and efficacy of the prepared surfaces in separating the two fluids. To summarize, this work presents a very simple and effective route for oil-water separation with high efficiency.

This paper focuses on thermodynamic balancing of the regeneration process in a hybrid liquid desiccant cooling/desalination system. The thermal balancing technique is investigated by adding a single extraction between the system regenerator and condenser. This technique is considered as a potential method to reduce energy consumption and increase the hybrid system performance, dramatically. The mathematical procedure to model the proposed system using enthalpy pinch is outlined to study the effect of extraction on the hybrid system performance. The hybrid system, with a single extraction and without extraction (zero extraction), is analyzed in terms of the normalized entropy generation, local enthalpy losses, the coefficient of performance, and proper extraction location. The results show that at enthalpy pinch of 20 kJ per kg of dry air, single extraction system performance is 85.7% better than zero extraction. In addition, the single extraction produces 103.2 kg of fresh water per hour as a by-product compared to 94.2 kg per hour for the zero extraction system.

In a conventional HDH system, a constant feed of seawater is required to run the system. As a result of extracting freshwater from the saline water, it is rejected at higher salinity, thus it cannot be recirculated as a feed again. The aim of this study is to come up with a zero-brine discharge system that eliminates the continuous need for the supply of source and sink in the conventional system. Based on the fact that earth's atmosphere holds a vast amount of water that can be considered as a reliable freshwater resource, especially in coastal areas. A water-from-air system is proposed in this study. The proposed system configuration comprises of two parts, a basic HDH system that uses a liquid desiccant solution instead of saline water and a desiccant-based air dryer. The liquid desiccant leaves the HDH part at a higher concentration due to the extraction of freshwater. It then enters the air dryer where it is diluted by absorbing water vapor from the ambient air. This diluted desiccant is directed to the HDH part to close the desiccant loop. In this study, Lithium chloride is used as the working fluid of the proposed system. Mathematical modeling of heat and mass transfer processes between the air and desiccant in the humidifier and dehumidifier is developed to predict the performance of the desalination system. The proposed system produces about 8 kg of freshwater per hour.

Sulfate reducing bacteria (SRB) wreaks havoc in the oil industry by being an agent for oil souring and building corrosion in pipelines and thereby degrade the quality of crude oil. Palladium nanoparticles decorated silicon carbide nanomaterial (Pd-SiC) was synthesized by a facile single step synthesis process and this nanomaterial as a photo-catalyst, as compared to pure silicon carbide (SiC) nanoparticles showed a significant enhancement in the photo-catalytic efficiency in the process of the photo-catalytic deactivation of hazardous SRB. The morphological characterization studies such as Field emission scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy unambiguously revealed that SiC surface was successfully decorated with palladium (Pd) nanoparticles. Also the Pd nanoparticles decorated on the SiC surface was further substantiated by EDX and elemental mapping analysis, which clearly revealed the presence of Pd along with Si and O. The band gap energy estimated using Diffuse reflectance spectra (DRS) showed the reduction of band gap energy from 2.82 eV to 2.72 eV. The observed enhancement in the efficiency of photo-catalytic deactivation of SRB with Pd-SiC can be attributed to the significant reduction in the recombination of photo-generated charge carriers, characteristically resulting from the metal (Pd) semiconductor (SiC) junction established by this synthesis process.

This review focuses on the thermal-hydraulic performance correlations for the air-side of compact and microchannel heat exchangers. These correlations are presented in tables, mainly in terms of Colburn j-factor and fanning friction factor (f), based on each type of fin arrangements with appropriate constraints including Reynolds number ranges, geometrical parameter limits, and fitting uncertainties. The correlations used for air-side arrangements of mini/micro channels, which are constructed in slabs, are the same as those used for the compact heat exchangers. In particular, these correlations are used for louver-fin, wavy-fin, offset strip-fin, and extended surfaces (plain fins and pin fins) arrangements. However, the correlations proposed for fin-and-tube (round) are only valid for the compact heat exchangers. We have also compared some correlations with the experimental data of Kays and London standard reference. Some performance correlations are generalized (as one correlation for each j- and f-factor) to represent all louver-fin types. However, other fin arrangements have distinct correlations based on their specific geometry. The most reported correlations are valid for dry fin conditions, whereas there are limited correlations devoted to wet or frost surfaces. A guideline based on this study is provided to facilitate the use of correlations for various configurations.

In this study, exergo-economic analysis of two layouts of humidification-dehumidification (HDH) desalination systems driven by a vapor compression heat pump (HP) is presented and discussed. The systems are closed-air open-water water-heated cycle coupled with a heat pump (HP-HDH-WH), and modified air-heated cycles integrated with a heat pump (HP-HDH-AH). For the purpose of comparison, a conventional closed-air open-water (CAOW) electric water heated HDH system (E-HDH-WH) is also presented. Exergy destruction, exergetic efficiency and product cost are evaluated for these systems. The influence of input parameters such as mass flowrate ratio, dehumidifier effectiveness, compressor isentropic efficiency, and feed water temperature on second-law efficiency and exergy destruction associated with the major components of the systems are analyzed. The impact of input cost parameters is investigated using two different approaches. The analysis shows that evaporator and compressor are the components with the largest exergy destruction. The exergy efficiency for the HP-HDH air-heated unit, HP-HDH water-heated unit, and E-HDH water-heated unit is found to be 1.097%, 0.06965% and 0.05795%, respectively. The cost of desalinated water evaluated by current analysis for HP-HDH air-heated system, HP-HDH water-heated cycle, and E-HDH water-heated unit is found to vary from 4.61$/m3 to 5.49$/m3, 6.00$/m3 to 7.14$/m3, and 4.44$/m3 to 14.95$/m3, respectively. The results generally reveal that HP-HDH air-heated cycle shows better performance both from energetic and exergetic viewpoints.

Electrodialysis desalination (ED) is an efficient process to desalinate brackish water and to minimize brine salinities to the level of seawater salinity. From the many models reported in the literature, some are simple but have a limited accuracy while others are complicated with a good accuracy. In this context, we explore the improvement of a fundamentally ‘lumped’ model by considering the voltage drop at the interfaces between membranes and solutions (which is the so-called Donnan potential) while conserving the model simplicity. The present model is developed by accounting for an electrical resistance of the Donnan potential in the total cell pair resistance. The results are presented in terms of total membrane area, flow path length, number of stacks and specific energy consumption. The results show that the improvement resulting from involving the Donnan potential was substantial for a high difference between the feed and product salinities as well as for low salinities (

The differential equations of momentum and heat transfer are similar to each other based on some assumptions, leading to exact analogous equations. These analogies have since been the focus of attention and their applicability is explored in many fields and flow types. In some cases, these analogies hold valid even if the theoretical foundation is not available for such conditions. The Reynolds and Chilton-Colburn analogy are the focus of the current work, with four types of flow situations including, Couette flow, tube flow, parallel plate and flow over a flat surface. The numerical results show the best match for parallel flow and flat plate, while Couette flow resulted in large differences (by a factor up to 3.3).

Humidification dehumidification (HDH) systems are robust and known to withstand a wide range of saline water without the need of complex maintenance. In this study, the closed-air open-water (CAOW) HDH arrangement is examined, which can easily be integrated with solar or other renewable resources. Also, this system is modified by incorporating heat recovery options for low performing units. The heat recovery process is executed through two approaches, (i) a mixing chamber and, (ii) by a heat exchanger. Thermal balancing through air extraction is evaluated for the basic as well as the modified cycles, particularly for high performing units. Zero, single and double extractions models are evaluated for the conventional CAOW water heated cycle. The performance of the systems is characterized into three operating regions (high, moderate and low) based on the effectiveness of the components. Based on the results of this evaluation, an operating scheme is then developed to decide where to use the conventional or the modified systems with or without extraction.

Humidification dehumidification (HDH) desalination system is a thermal-based desalination technology that is suitable for small-scale water desalination applications. In this paper, we present an experimental and thermodynamic analysis of the energetic performance of two HDH cycles. The HDH cycles considered are the basic open-air open-water (OAOW) cycle and the modified closed-water open-air (CWOA) cycle with the options of brine recirculation. An experimental investigation is performed on the modified cycle to validate the theoretical model that is used to assess the energetic performance of both the basic and modified cycles. The theoretical model is found to be in a good agreement with the experimental data with a maximum percentage deviation of 5% from the experimental data. Furthermore, limiting cases of the system are explored. Within the limiting cases, the modified cycle recorded about 100% improvement in the energy performance over the basic cycle due to heat recovery process associated with the modified cycle. Additionally, a cost analysis was performed to determine the cost of freshwater production by the presented desalination cycles. Results show that the freshwater price varied from 4.10 to 6.55 $/m3 and 0.79 to 2.25 $/m3 for the basic OAOW HDH cycle and the modified CWOA HDH cycle, respectively.

Recently, recommender systems are getting popular in the e-commerce industry for retrieving and recommending most relevant information about items for users from large amounts of data. Different stochastic gradient descent (SGD) based adaptive strategies have been proposed to make recommendations more precise and efficient. In this paper, we propose a fractional variant of the standard SGD, named as fractional stochastic gradient descent (FSGD), for recommender systems. We compare its convergence and estimated accuracy with standard SGD against a number of features with different learning rates and fractional orders. The performance of our proposed method is evaluated using the root mean square error (RMSE) as a quantitative evaluation measure. We examine that the proposed strategy is more accurate in terms of RMSE than the standard SGD for all values of fractional orders and different numbers of features. The contribution of fractional calculus has not been explored yet to solve the recommender systems problem; therefore, we exploit FSGD for solving this problem. The results show that our proposed method performs significantly well in terms of estimated accuracy and convergence as compared to the standard SGD.

Humidification-dehumidification is a carrier gas based thermal technique that is ideal for small-scale water desalination applications. One advantage of humidification-dehumidification systems is the ability to utilize low grade and renewable energies as heat source to drive the system. This work presents theoretical investigation of humidification-dehumidification desalination system operated by a heat pump. The model is based on the first law of thermodynamics, describing heat and mass transfer in the combined humidification-dehumidification-heat pump cycle. The model predicts the performance of closed-air open-water water-heated, and modified air-heated cycle coupled with a heat pump. To improve the Gain output ratio and energy recovery of the system, a heat pump is used as the source of heating and cooling for the humidification-dehumidification desalination system. Energy rejected in the condenser is used as a source of heat in the humidifier whereas the cooling effect of the evaporator is used to cool incoming seawater for effective condensation of humid air in the dehumidifier. A parametric study is conducted to investigate the influence of system operating parameters, including water and air flowrate, seawater temperature, and refrigerant flow rate on the system performance. Results indicate a maximum Gain output ratio of 8.88 and 7.63 obtained at 80% components effectiveness and mass flow rate ratio of 0.63 and 1.3 for modified air heated and water heated cycle, respectively. A maximum gain output ratio greater than 10 can be achieved for humidifier and dehumidifier effectiveness of 100% leading to more energy efficient systems. The cost of desalinated water production is calculated and the effect of major parameters on its variation is also presented.

The analysis for fin thermal performance under dehumidifying conditions is conducted using a numerical approach. Finite-Element method is used to account for the non-linear effects due to temperature dependent parameters and humidity-temperature relationship. The temperature profiles, as well as the overall fin efficiency, are studied. The fin efficiency is found to be highly dependent on the operating conditions and the degree to which the heat transfer coefficient is a function of temperature. It is found that the effect of temperature-dependent thermal conductivity on fin performance is less as compared to heat transfer coefficient over the considered range of operating conditions.

In this paper, strength of fractional adaptive signal processing is exploited for parameter identification of control autoregressive autoregressive (CARAR) systems using normalized version of fractional least mean square (FLMS) and its recently introduced modification of type 1 and 2. The adaptation performance of the proposed normalized FLMS methods is compared with standard counterparts for CARAR identification model by taking different noise levels as well as fractional orders. The results of the statistical analyses are used to validate the consistency of the proposed normalized fractional adaptive methodologies in terms of convergence, accuracy and robustness. The reliability and effectiveness of the design schemes is further validated through consistently approaching the desired identification parameters based on performance metrics of mean square error, variance account for and Nash–Sutcliffe efficiency.