This research experimentally analyzed the impacts of various water cement (W/C) ratios of ultrafine cement grout material and normal loads FN applied to fractures on grout nonlinear flow behavior through a rough plexiglass fractured sample. An effective self-made apparatus was designed and manufactured to conduct the stress-dependent grout flow tests on the plexiglass sample containing rough fractures. At each W/C ratio, the grout pressure P increased from 0 to 0.9 MPa, and the normal loads FN ranged from 666.3 to 1467.8 N. The results of the experiments indicate that (1) the Forchheimer’s law can be used to express the results of grout nonlinear flow through rough fractures. Moreover, both nonlinear coefficient a and linear coefficient b in Forchheimer’s law decreased with the increase of the W/C ratio, but increased with the increase of the FN value. (2) For normalized transmissivity, with the increase of Re, the decline of the T/T0−Re curves means that the grout flow behavior throug... [more]

Iron ore was studied as a CO2 absorbent. Carbonation was carried out by mechanochemical and high temperature−high pressure (HTHP) reactions. Kinetics of the carbonation reactions was studied for the two methods. In the mechanochemical process, it was analyzed as a function of the CO2 pressure and the rotation speed of the planetary ball mill, while in the HTHP process, the kinetics was studied as a function of pressure and temperature. The highest CO2 capture capacities achieved were 3.7341 mmol of CO2/g of sorbent in ball milling (30 bar of CO2 pressure, 400 rpm, 20 h) and 5.4392 mmol of CO2/g of absorbent in HTHP (50 bar of CO2 pressure, 100 °C and 4 h). To overcome the kinetics limitations, water was introduced to all carbonation experiments. The calcination reactions were studied in Argon atmosphere using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Siderite can be decomposed at the same temperature range (100 °C to 420 °C) for the samples... [more]

In the search for oils of commercial interest that serve as new sources for the generation of cosmetic, pharmaceutical, or nutraceutical products, the green coffee beans oil (Coffea arabica L.) was studied. This research aimed to evaluate the oxidative stability of microencapsulated green coffee oil (Coffea arabica) by spray drying. The green coffee oil emulsions were produced by microfluidization using mesquite gum and octenyl succinic anhydride modified starches (OSA-starch) as wall-material. The particle size, polydispersity, and zeta potential on the microfluidized emulsions were optimized. The results showed that microfluidization had positive effects on the reduction of the emulsion droplets and the zeta potential, developing stable emulsions for both polymers. Then, the optimal microfluidization conditions were used to evaluate the impact of the spray drying conditions on the microencapsulation efficiency, morphology, and oxidation stability of the green coffee oil microcapsules... [more]

Unit Commitment (UC) requires the optimization of the operation of generation units with varying loads, at every hour, under different technical and environmental constraints. Many solution techniques were developed for the UC problem, and the researchers are still working on improving the efficiency of these techniques. Particle swarm optimization (PSO) is an effective and efficient technique used for solving the UC problems, and it has gotten a considerable amount of attention in recent years. This study provides a state-of-the-art literature review on UC studies utilizing PSO or PSO-variant algorithms, by focusing on research articles published in the last decade. In this study, these algorithms/methods, objectives, constraints are reviewed, with focus on the UC problems that include at least one of the wind and solar technologies, along with thermal unit(s). Although, conventional PSO is one of the most effective techniques used in solving UC problem, other methods were also develo... [more]

This paper proposes an adaptive overall control strategy of the permanent magnet synchronous generator-based wind energy conversion system (WECS) in the whole wind speed range. For the machine side, the maximum power point tracking (MPPT) operation is realized by stator current and mechanical rotation speed control under below-rated wind speeds. Under above-rated wind speeds, the extracted wind power is limited via pitch control. For the grid side, the reactive and active power injected into grid is regulated by DC-Link voltage and grid current control loop. In addition, under grid voltage dips, the pitch control is employed for limiting grid current and maintaining the DC-Link voltage around its rated value. The fault ride-through capability (FRTC) can be enhanced. The overall control strategy is based on perturbation estimation technique. A designed observer is used for estimating the perturbation term including all system nonlinearities, uncertainties and disturbances, so as to comp... [more]

The importance of neural network (NN) modelling is evident from its performance benefits in a myriad of applications, where, unlike conventional techniques, NN modeling provides superior performance without relying on complex filtering and/or time-consuming parameter tuning specific to applications and their wider ranges of conditions. In this paper, we employ NN modelling with training data generation based on sensitivity analysis for the prediction of building energy consumption to improve performance and reliability. Unlike our previous work, where insignificant input variables are successively screened out based on their mean impact values (MIVs) during the training process, we use the receiver operating characteristic (ROC) plot to generate reliable data with a conservative or progressive point of view, which overcomes the issue of data insufficiency of the MIV method: By properly setting boundaries for input variables based on the ROC plot and their statistics, instead of complet... [more]

The pressure swing distillation (PSD) with two different energy-saving modes are put forward to separate a binary azeotrope containing lower alcohols: benzene/methanol. A comparison of the economy and controllability for the partial and fully heat integrated pressure swing distillation (HIPSD) is made by detailed simulation analysis. The optimal operating parameters of partial and fully HIPSD processes are obtained by minimizing total annual cost (TAC). These results show that the fully HIPSD mode saves 5.88% TAC compared with the partial HIPSD mode. Meanwhile, this paper proposes that the composition slope profile can help to select the temperature control stage (TCS), when the temperature profile in the column is rising rapidly near the bottom and the maximum of temperature slope value occurs in the bottom of the column. Several control structures are developed to check the rationality of the selection of the TCS and evaluate the industrial application. These results illustrate the c... [more]

In this work, used lube oil was treated using natural acid-free clay. Clay was added at different amounts (5, 10, and 20 g) to 100 mL of waste engine oil at various temperatures (250, 350, 400, and 450 °C) and mixed at a speed of 800 rpm for 30 min. After settling and separation, the treated oil was diluted with kerosene before being examined using a Ultraviolet−visible (UV) spectrophotometer. In order to achieve cost-effective recycling, this process is modeled using the response surface method (RSM). Five regression models (linear, quadratic, Two Factor Interactions (2FI), cubic, and reduced-order quadratic model) were developed, then tested, and examined by calculating the statistical performance indicators (R2, R2adj, Akaike’s Information Criterion corrected (AICc), Bayesian Information Criterion (BIC), and Root Mean Square Error (RMSE)). The results obtained reveal that the modified quadratic model outperforms the rest of the models in terms of the low value of RMSE, the lowest AI... [more]

A high specific speed centrifugal pump is used in the situation of large flow and low head. Centrifugal pump parameters need to be optimized in order to raise its head and efficiency under off-design conditions. In this study, the orthogonal experiment design method is adopted to optimize the performance of centrifugal pump basing on three parameters, namely, blade outlet width b2, blade outlet angle β2 and blade wrap angle φ. First, the three-dimensional model of the centrifugal pump is established by CFturbo and SolidWorks. Then nine different schemes are designed by using orthogonal table, and numerical simulation is carried out in CFX15.0. The final optimized combination of parameters is b2 = 24 mm, β2 = 24°, φ = 112°. Under the design condition, the head and efficiency of the optimized centrifugal pump are appropriately improved, the increments of which are 0.74 m and 0.48%, respectively. However, the efficiency considerably increases at high flow rates, with an increase of 6.9% a... [more]

The integration of drugs into nanocarriers favorably altered their pharmacodynamics and pharmacokinetics compared to free drugs, and increased their therapeutic index. However, selective cellular internalization in diseased tissues rather than normal tissues still presents a formidable challenge. In this chapter I will cover solutions involving environment-responsive cell-penetrating peptides (CPPs). I will discuss properties of CPPs as universal cellular uptake enhancers, and the modifications imparted to CPP-modified nanocarriers to confine CPP activation to diseased tissues.

A mathematical model has been developed for heat exchange in nucleate boiling at high flux applying an energy balance on a macrolayer. The wall superheat, macrolayer thickness, and time are the parameters considered for predicting the heat flux. The influence of the wall superheat and macrolayer thickness on average heat flux has been predicted. The outcomes of the current model have been compared with Bhat’s constant macrolayer model, and it was found that these models are in close agreement corresponding to the nucleate pool boiling regime. It was concluded that the wall superheat and macrolayer thickness contributed significantly to conduction heat transfer. The average conduction heat fluxes predicted by the current model and by Bhat’s model are in close agreement for a thinner macrolayer of approximately 50 µm. For higher values of the wall superheat, which corresponds to the nucleate pool boiling condition, the predicted results strongly agree with the results of Bhat’s model. Th... [more]

To overcome the difficulty of accurately determining the load state of a wet ball mill during the grinding process, a method of mill load identification based on improved empirical wavelet transform (EWT), multiscale fuzzy entropy (MFE), and adaptive evolution particle swarm optimization probabilistic neural network (AEPSO_PNN) classification is proposed. First, the concept of a sliding frequency window is introduced based on EWT, and the adaptive frequency window EWT algorithm, which is used to decompose the vibration signals recorded under different load states to obtain the intrinsic mode components, is proposed. Second, a correlation coefficient threshold is used to select the sensitive mode components that characterize the state of the original signal for signal reconstruction. Finally, the MFE of the reconstructed signal is used as the characteristic vector to characterize the load state of the mill, and the partial mean value of MFE is calculated. The results show that the mean... [more]

Rotating packed bed (RPB) has been demonstrated as a significant and emerging technology to be applied in natural gas desulfurization. However, droplet characteristics and principle in H2S selective absorption with N-methyldiethanolamine (MDEA) solution have seldom been fully investigated by experimental method. Therefore, a 3D Eulerian−Lagrangian approach has been established to investigate the droplet characteristics. The discrete phase model (DPM) is implemented to track the behavior of droplets, meanwhile the collision model and breakup model are employed to describe the coalescence and breakup of droplets. The simulation results indicate that rotating speed and radial position have a dominant impact on droplet velocity, average residence time and average diameter rather than initial droplet velocity. A short residence time of 0.039−0.085 s is credited in this study for faster mass transfer and reaction rate in RPB. The average droplet diameter decreases when the initial droplet ve... [more]

Limiting global temperature rise to well below 2 °C according to the Paris climate accord will require accelerated development, scale-up, and commercialization of innovative and environmentally friendly reactor concepts. Simulation-based design can play a central role in achieving this goal by decreasing the number of costly and time-consuming experimental scale-up steps. To illustrate this approach, a multiscale computational fluid dynamics (CFD) approach was utilized in this study to simulate a novel internally circulating fluidized bed reactor (ICR) for power production with integrated CO2 capture on an industrial scale. These simulations were made computationally feasible by using closures in a filtered two-fluid model (fTFM) to model the effects of important subgrid multiphase structures. The CFD simulations provided valuable insight regarding ICR behavior, predicting that CO2 capture efficiencies and purities above 95% can be achieved, and proposing a reasonable reactor size. The... [more]

The study of laminar flow of heat and mass transfer over a moving surface in bionanofluid is of considerable interest because of its importance for industrial and technological processes such as fabrication of bio-nano materials and thermally enhanced media for bio-inspired fuel cells. Hence, the present work deals with the unsteady bionanofluid flow, heat and mass transfer past an impermeable stretching/shrinking sheet. The appropriate similarity solutions transform the boundary layer equations with three independent variables to a system of ordinary differential equations with one independent variable. The finite difference coupled with the Richardson extrapolation technique in the Maple software solves the reduced system, numerically. The rate of heat transfer is found to be higher when the flow is decelerated past a stretching sheet. It is understood that the state of shrinking sheet limits the rate of heat transfer and the density of the motile microorganisms in the stagnation reg... [more]

The oscillating flow field of the double nozzle flapper servo valve pre-stage is numerically analyzed through Large Eddy Simulation (LES) turbulent modeling with the previous grid independence verification. The vortex street flow phenomenon can be observed when the flow passes through the nozzle flapper channel, the vortex alternating in each side produces the periodical flow oscillation. The structural and flow parameter effects on the oscillating flow are emphasized, and it could be determined that the pressure on the flapper is nearly proportional to the flow velocity and inversely proportional to the actual distance between the flapper and the nozzle. On the other hand, the main frequency of oscillation decreases with the velocity and increases with the distance between the nozzle flapper. The main stage movement is further considered with a User Defined Function (UDF), and it could be determined that the influences of the structural and flow parameters on the flow oscillation are... [more]

In metallurgical and chemical engineering processes, the gas−liquid−liquid multiphase flow phenomenon is often encountered. The movement of bubbles in the liquid, and the influence of bubbles on the liquid−liquid interface, have been the focus of extensive research. In the present work, an air−water−oil system was used to explore the movement of bubbles and the phenomenon that occurs when bubbles pass through an interface with various oil viscosities at various gas flow rates. The results show that bubble movement is greatly influenced by the viscosity of the oil at low gas flow rates. The type of phase entrainment and the jet height was changed when increasing the gas flow rate. The stability of the water−oil interface was enhanced with increasing viscosity of the oil phase.

Conventional indoor climate design and control approaches are based on static thermal comfort/sensation models that view the building occupants as passive recipients of their thermal environment. Recent advances in wearable sensing technologies and their generated streaming data are providing a unique opportunity to understand the user’s behaviour and to predict future needs. Estimation of thermal comfort is a challenging task given the subjectivity of human perception; this subjectivity is reflected in the statistical nature of comfort models, as well as the plethora of comfort models available. Additionally, such models are using not-easily or invasively measured variables (e.g., core temperatures and metabolic rate), which are often not practical and undesirable measurements. The main goal of this paper was to develop dynamic model-based monitoring system of the occupant’s thermal state and their thermoregulation responses under two different activity levels. In total, 25 participan... [more]

As the core control system of a rolling mill, the hydraulic automatic gauge control (HAGC) system is key to ensuring a rolling process with high speed, high precision and high reliability. However, a HAGC system is typically a mechanical-electric-hydraulic coupling system with nonlinear characteristics. The vertical vibration of the load easily occurs during the working process, which seriously affects the stability of the system and the causes are difficult to determine. In this work, the theory and method of nonlinear dynamics were employed. The load vertical vibration model of the HAGC system was established. Then, the multi-scale method was utilized to solve the obtained model, and the singularity theory was further applied to derive the transition set. Moreover, the research object of this article focused on some nonlinear factors such as excitation force, elastic force and damping force. The effects of the above feature parameters on bifurcation behavior were emphatically explore... [more]

In a biological treatment process, hydraulic retention time (HRT) has a certain effect on the operation of the reactor. This study investigated the effect of HRT on carbon sequestration in a two-stage anaerobic ammonium oxidation (anammox) process using a partial nitrification reactor and anammox reactor to determine the optimal carbon sequestration operating conditions. Molecular biotechnology was used to analyze the sludge in the reactor in order to explore the denitrification performance and to determine the carbon sequestration pathway of the microorganisms. The results show that the partial nitrification stage had the highest carbon sequestration rate (0.319 mg/mg·N) when the nitrogen loading rate (NLR) was 0.44 kg·N/m3/d. The NLR of the anammox stage was 0.13 kg·N/m3/d. When the HRT was 33.4 h, the carbon sequestration of the anammox reaction was at its highest, reaching 0.183 mg/mg·N. The results of microbial analysis show that the carbon-fixing gene cbbLR1 was present in the sl... [more]

Triboelectric separation is a promising technology to separate fine powders. To enable triboelectric separation for its application in industry, the impact of the process and product parameters must be examined. In this study, with regards to different wall materials in the charging step (PTFE, POM, PE, PVC, and PMMA), the influence of the powder composition of a binary starch-protein mixture with a protein content of 15 wt.%, 30 wt.% and 45 wt.% was studied. By increasing the protein content in the feed, the separation selectivity increased. No dependency of the empirical triboelectric series was determined for all powder compositions. The variation in the protein content of the initial powder and turbulent flow profiles results in a variation in the contact number of particles calculated. An increase in the contact number of particles leads to an increase in the protein content separated on the cathode, whereas the protein content on the anode is only slightly affected. These finding... [more]

This study aimed to observe the potential of solid bioethanol as an alternative fuel with high caloric value. The solid bioethanol was produced from liquid bioethanol, which was obtained from the synthesis of oil palm empty fruit bunches (PEFBs) through the delignification process by using organosolv pretreatment and enzymatic hydrolysis. Enzymatic hydrolysis was conducted using enzyme (60 FPUg−1 of cellulose) at a variety of temperatures (35 °C, 70 °C, and 90 °C) and reaction times (2, 6, 12, 18, and 24 h) in order to obtain a high sugar yield. The highest sugars were yielded at the temperature of 90 °C for 48 h (152.51 mg/L). Furthermore, fermentation was conducted using Saccharomyces cerevisiae. The bioethanol yield after fermentation was 62.29 mg/L. Bioethanol was extracted by distillation process to obtain solid bioethanol. The solid bioethanol was produced by using stearic acid as the additive. In order to get high-quality solid bioethanol, the calorific value was optimized using... [more]

Neodymium (Nd)-substituted cobalt ferrite nanoparticles (NPs), i.e., CoNdxFe2−xO4 (0.0 ≤ x ≤ 0.2) NPs, were synthesized by the sonochemical method. The compositional characterization was done by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Antistaphylococcal activity was found to be enhanced, i.e., survival rate was 50%, 45%, 40%, and 30% with the increase in the ratio of Nd (0.0 ≤ x ≤ 0.2), whereas anticandidal activity was found efficient, i.e., 9%, 20%, 22%, and 40% survival rate at all the four ratios. The morphogenesis studies indicated that the synthesized metal−ligand, improves the antimicrobial capacity by binding them strongly to the microbial walls. To the best of our knowledge, this is the first report which demonstrates the series of CoNdxFe2−xO4 (0.0 ≤ x ≤ 0.2) NPs being active towards Staphylococcus aureus and Candida albicans and encourages its potential candidature for pharmaceuti... [more]

The maximum sensitivity function as the conventional robustness index is often used to test the robustness and cannot be used to tune the controller parameters directly. To reduce analytical difficulties in dealing with the maximum sensitivity function and improve the control performance of the proportional-integral-derivative controller, the relative delay margin as a good alternative is proposed to offer a simple robust analysis for the proportional-integral-derivative controller and the first-order plus dead-time systems. The relationship between the parameters of the proportional-integral-derivative controller and the new pair, e.g., the phase margin and the corresponding gain crossover frequency, is derived. Based on this work, the stability regions of the proportional-integral-derivative controller parameters, the proportional gain and the integral gain with a given derivative gain, are obtained in a simple way. The tuning of the proportional-integral-derivative controller with c... [more]

Sugarcane juice is a perishable food with a good nutritional profile. Thus, there is a need to increase its shelf life by reducing water content which facilitates storage and transportation. In this study, process conditions were optimized to concentrate the sugarcane juice at various microwave powers (30, 50, 80, 100 W). A central composite design was applied to optimize the process conditions (power and time). The overall evaporation time depends on microwave powers; increase in power reduced the processing time. The results showed that at 100 W sugarcane juice was concentrated to 75° brix for 15 min which reduced the energy consumption to 1.3 times compared to other powers. Moreover, microwave processing better retained the sensory properties of concentrate and preserved its antioxidant activity. Thus, 100 W was most energy efficient in concentrating sugarcane juice. In general, microwave processing reduced the processing time and cost making it a sustainable approach to concentrate... [more]