Search

Abstract: Ethylenediamine-doped (EDA-doped) polyaniline (PANI) films were deposited via spin coating technique on a glass substrate. The samples were annealed at different times and temperatures. The characterizations of the prepared PANI films were described by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). It is found that the conductivity changes under deep mouth exhaling for 150/1 h sample is 1.65 times faster than the films annealed at 100°C/4 h. The response and recovery time of the 150/1 h EDA-doped PANI film is decreased by order of 0.63 and 1.29 s than those films dried at 100°C for 4 h, respectively. The 150/1 h EDA doped PANI film during deep exhaling its conductivity increased abruptly from 2.2 × 10–7to 0.026 S/cm–1. In a few seconds, following an inhalation, there occurs a complete transition to the dry state conductivity. Furthermore, the increment in conductivity of the EDA-doped PANI films was determined at various RH levels (20, 40, 60, 80, and 90%) with exposure and evacuation of the humid air. The doped PANI sample annealed at 150°C for 1 h exhibit the highest conductivity at 90% RH. The conductivity was increased from 2.16 × 10–7S/cm for the insulating state at the dry state to 0.23 S/cm for the semiconducting state at 90% RH. Consequently, the 150/1 h sample showed an increase in conductivity by order of 106at 90% RH. For all samples, the conductivity progressively rises as the RH value increases till 90% of RH value samples exhibit an abrupt increase in conductivity except the 100°C/4 h sample. The highest conductivity is 0.041 S/cm at 90% RH obtained for the case of 150/30 min sample, whereas the 150/1 min and 100/4 h films show maximum conductivity of 0.027 and 0.007, respectively.

We aimed to study the association of very low serum Lipoprotein(a) [Lp(a)] concentrations with new-onset type 2 diabetes (T2D) and non-alcoholic liver disease (NAFLD) in the context of statin usage in the UK Biobank, a large prospective population cohort.

The study considers issues of elaborating and validating a technique of autonomous vehicle motion planning based on sequential trajectory and speed optimization. This method includes components such as representing sought-for functions by finite elements (FE), vehicle kinematic model, sequential quadratic programming for nonlinear constrained optimization, and Gaussian N-point quadrature integration. The primary novelty consists of using the inverse approach for obtaining vehicle trajectory and speed. The curvature and speed are represented by integrated polynomials to reduce the number of unknowns. For this, piecewise functions with two and three degrees of freedom (DOF) are implemented through FE nodal parameters. The technique ensures higher differentiability compared to the needed in the geometric and kinematic equations. Thus, the generated reference curves are characterized by simple and unambiguous forms. The latter fits best the control accuracy and efficiency during the motion tracking phase. Another advantage is replacing the nodal linear equality constraints with integral nonlinear ones. This ensures the non-violation of boundary limits within each FE and not only in nodes. The optimization technique implies that the spatial and time variables must be found separately and staged. The trajectory search is accomplished in the restricted allowable zone composed by superposing an area inside the external and internal boundaries, based on keeping safe distances, excluding areas for moving obstacles. Thus, this study compares two models that use two and three nodal DOF on optimization quality, stability, and rapidity in real-time applications. The simulation example shows numerous graph results of geometric and kinematic parameters with smoothed curves up to the highest derivatives. Finally, the conclusions are made on the efficiency and quality of prognosis, outlining the similarities and differences between the two applied models.

ABSTRACTSingle and multi-vehicle (SMV) crashes remain a significant issue, causing serious safety and economic concerns, and therefore deserve more attention. Using crash data in the Beijing-Shanghai and Changchun-Shenzhen freeways over the five years (2015–2019), this paper explored the transferability and heterogeneity for crash type (single-vehicle versus multi-vehicle crashes) and spatiotemporal stability of determinants affecting the injury severity. The random parameters logit approach with heterogeneity in means and variances was used to model three possible crash injury severity outcomes (measured by the most severely injured individual in the crash) of no injury, minor injury, and severe injury and identify the determinants in terms of driver, vehicle, roadway, environment, temporal, spatial, traffic, and crash characteristics. Remarkable differences were observed in the SMV crashes, and the contributing factors also reported considerable temporal and (or) spatial instabilities. The insights of this study should be valuable to help freeway designers and decision-makers understand the contributing mechanism of the factors and develop the proper management strategies and enforcement countermeasures.

ABSTRACT This paper presents a preliminary study of the damping performance (DP) and mechanism of crumb rubber modified (CRM) asphalt. The loss factor (IF) temperature spectra of a dynamic shear [...]

ABSTRACT The objective of this study is to investigate the effect of the steel fiber (STF) contents (0, 0.5%, 1% and 2%) on the tensile basic creep behavior of lightweight [...]

ABSTRACT Based on the specific features of cement-derived materials gained by incorporation of nanomaterials, such as proper workability and accelerated hydration reaction, investigations of nano-modification of cementitious materials are increasingly [...]

Opportunity recognition is an important aspect of entrepreneurship for young entrepreneurs to acquire through networking with different actors. However, little is known about the effect of entrepreneurial networking on the opportunity recognition of young entrepreneurs. Using a moderated mediation model of proactiveness and entrepreneurial self-efficacy, the study examined the effect of entrepreneurial networking on the opportunity recognition of young entrepreneurs. As such, social network and social cognitive theories guided this study, employing a quantitative research design. The study found that entrepreneurial networking has a positive effect on the opportunity recognition of young entrepreneurs. It found that proactiveness has both a significant negative interaction effect and is the contingent factor for the indirect effect of entrepreneurial self-efficacy on entrepreneurial networking and opportunity recognition of young entrepreneurs. The findings have theoretical and managerial implications; entrepreneurial networking impacts opportunity recognition and increases the ability of young entrepreneurs to access more entrepreneurial opportunities.

Pyrimido[4,5-b]quinoline is a vital structural motif. The synthesis of pyrimido[4,5-b]quinolines has been a challenging topic in medicinal chemistry. A wide range of starting materials have been employed to achieve this nucleus such as quinoline derivatives and isatins. Multi-component one-pot synthestic approaches were employed either by using barbituric or thiobarbituric acid, amines and aldehydes or from 6-aminouracils, aldehydes and cyclohexanone derivatives. Recent synthetic strategies and many green chemistry techniques have improved pyrimido[4,5-b]quinolines synthesis over the last twenty years. Among the many reported biological activities of pyrimido[4,5-b]quinolines, anticancer activity attracted research attention over the past couple of decades. Many derivatives have shown promising anticancer activity on different cancer cell lines such as MCF-7, A549, K562 and others. They also demonstrated activity on different enzymes and receptors such as tyrosine kinases, tyrosyl-DNA Phosphodiesterase II and HDM2 ubiquitin ligase (E3) that promote apoptosis, repair DNA damage, and induce cell cycle arrest. This review critically examines the recent synthetic approaches employed for the synthesis of pyrimido[4,5-b]quinolines and explores their reported anticancer activities.

ABSTRACT Sea water curing (SWC, 20 [+ or -]2[degrees]C) has been proposed to obtain economic benefits for green artificial reef concrete (GARC) in coastal areas. This study evaluated the feasibility [...]

Roadside monitoring Lidars (RMLs) will be a crucial part of the future intelligent transportation system. Current approaches for optimizing RMLs’ placement at intersections work in hypothetical environments which do not well reflect real-world situations. This article proposes a new virtual method (VM) for optimizing the deployment of RMLs at as-built intersections. The proposed VM operates in a virtual environment where both static background and dynamic agents are modeled by dense point clouds. The agents are driven by real-world motion data. Using RMLs’ parameters as inputs, a coarse-to-fine subsampling approach is developed to generate laser scans in the virtual world. An objective function is then defined by comparing the agents’ points in the generated laser scan sequences against their original models. Bayesian optimization is applied to maximize the objective function by setting the RMLs’ positions and poses as decision variables. Besides, batch processing strategy and parallel computing are used to accelerate the optimization process. The effectiveness of the proposed VM is demonstrated in a case study. The VM shall help road administrators make decisions on RMLs’ deployment at as-built intersections.

A detailed experimental investigation of NOxemissions was conducted in order to get more precise combustion data for a Helmholtz resonator valveless pulse combustor. A laboratory-scale model of the combustor was designed and operated with a non-premixed input of air and propane. The effects of fuel flow rate, temperature, and pressure amplitude on NOxemissions through a variety of experimental tests were studied. The tests were carried out for three tailpipe lengths, two inlet pipe lengths, and two combustion chamber volumes. The results revealed that the variations in operational and design parameters have a significant impact on NOxemissions. NOxemissions reach a maximum value near the stoichiometric condition as temperature and pressure, which are related to the fuel flow rate, reach their maximum values. Experiments show inverse relationships between CO and NOxemissions. Furthermore, the findings show that NOxreduction increases with increasing tailpipe and inlet pipe lengths, as well as small volume combustion chambers.

Small newborns are vulnerable to mortality and lifelong loss of human capital. Measures of vulnerability previously focused on liveborn low-birthweight (LBW) babies, yet LBW reduction targets are off-track. There are two pathways to LBW, preterm birth and fetal growth restriction (FGR), with the FGR pathway resulting in the baby being small for gestational age (SGA). Data on LBW babies are available from 158 (81%) of 194 WHO member states and the occupied Palestinian territory, including east Jerusalem, with 113 (58%) having national administrative data, whereas data on preterm births are available from 103 (53%) of 195 countries and areas, with only 64 (33%) providing national administrative data. National administrative data on SGA are available for only eight countries. Global estimates for 2020 suggest 13·4 million livebirths were preterm, with rates over the past decade remaining static, and 23·4 million were SGA. In this Series paper, we estimated prevalence in 2020 for three mutually exclusive types of small vulnerable newborns (SVNs; preterm non-SGA, term SGA, and preterm SGA) using individual-level data (2010–20) from 23 national datasets (∼110 million livebirths) and 31 studies in 18 countries (∼0·4 million livebirths). We found 11·9 million (50% credible interval [Crl] 9·1–12·2 million; 8·8%, 50% Crl 6·8–9·0%) of global livebirths were preterm non-SGA, 21·9 million (50% Crl 20·1–25·5 million; 16·3%, 14·9–18·9%) were term SGA, and 1·5 million (50% Crl 1·2–4·2 million; 1·1%, 50% Crl 0·9–3·1%) were preterm SGA. Over half (55·3%) of the 2·4 million neonatal deaths worldwide in 2020 were attributed to one of the SVN types, of which 73·4% were preterm and the remainder were term SGA. Analyses from 12 of the 23 countries with national data (0·6 million stillbirths at ≥22 weeks gestation) showed around 74% of stillbirths were preterm, including 16·0% preterm SGA and approximately one-fifth of term stillbirths were SGA. There are an estimated 1·9 million stillbirths per year associated with similar vulnerability pathways; hence integrating stillbirths to burden assessments and relevant indicators is crucial. Data can be improved by counting, weighing, and assessing the gestational age of every newborn, whether liveborn or stillborn, and classifying small newborns by the three vulnerability types. The use of these more specific types could accelerate prevention and help target care for the most vulnerable babies.

The pursuit of low-cost manufacturing of newly effective pigments is a pressing economic need. Thus, in this work, low-cost ZnFe2O4spinel nanoparticles (ZF-NPs) with an average diameter of 20 nm were successfully synthesized using a simple sol–gel method, which can be extended for large-scale fabrication of a reddish nano pigment. TGA/DTA, XRD, DRS, HRTEM, and SEM/EDX investigations were used to characterize the as-prepared product. The color of synthesized NPs was studied using CIE L*a*b* colorimetric method with color coordinates of L* = 41.7, a* = 72.2, and b* = 48.8. The newly developed pigment was examined to be superior to the traditional pigment (M6001/Fe2O3: L* = 30.4, a* = 42.16, and b* = 45.7). After that, the synthesized nano pigment was integrated into both ink and paint formulations as a multifunctional coating. The inclusion of synthesized nano pigment in metal coating printing ink formulation was done to produce a good alternative and cost-effective substitute for the commercially available pigment used in the inks industry. Also, the effect of the fabricated nanoparticles on corrosion resistance and thermal stability of epoxy-based paint formulations was evaluated using different standard tests. Therefore, the ZnFe2O4pigment should be applied as a highly efficient inorganic nano pigment.

The mathematical modelling of the branched automotive drivetrain is mainly based on various configurations of differential mechanisms (DM). This paper proposes variant math approaches for modelling DM's dynamics. The symmetric (open) DM is considered first. Two mathematical methods based on ordinary differential equation (ODE) and differential-algebraic equation (DEA) problems are applied. The asymmetric self-locking inter-axle differential with proportional friction moments is then considered. Three variants of the mathematical models for this DM type are represented. The linearised model uses the shortest description based on a previous step solution. Two other nonlinear models are formed by mixing with ODE and DAE approaches. The Simulink blocks for implementing developments were composed. The models were validated by comparing the results under the same conditions to prove their math coherence. The analysis of the proposed variants was carried out regarding structural complexity, usability, computational speed, and relative accuracy. Conclusions about their usability in drivetrain dynamics and active control were made.

In order to improve the water disinfection (waste and drinking water) by photosensitization, thyme (Thymus vulgaris) essential oils were investigated in this study. A synthetic water samples including bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Salmonella typhi) were irradiated by an artificial ultraviolet lamp of brand UVA at 365 nm in the presence and in the absence of added concentration of thyme (Thymus vulgaris) essential oils (at nearly 5% w/v). After irradiation of an hour, samples were taken for bacteriological analyses. The exploitation of the results shows an enhancement of bacterial inactivation for irradiated samples containing a volume of thyme essential oil (TEO). This result could be interesting in further application for water treatment by photosensitization. In addition, the added volume of thyme essential oils affects distinctly the expression of virulence factors expressed by tested bacteria namely P. aeruginosa such as motility, enzyme production and biofilms formation. For instance, results reveal biofilm inhibitor effects of TEO despite the low added concentration compared to the irradiated bacteria without any addition. This fact could used to enhance water treatment without chemical addition and, also to overcome the disadvantages of water disinfection process such the non-remnant effect of UV irradiation and the post-treated bacterial resuscitation.

Graphical abstract:

In this work, a three-dimensional study is conducted for silicon ingot irradiation facility in a typical MTR reactor. The silicon ingot heat generation is allowed to change around its nominal value in the range of 0.25, 0.5, 0.75, 1.0, and 1.25 W/g. The dimensionless clearance ratio ζbetween the ingot and the outer casing is changed for values of 0.01, 0.05, 0.1, 0.15, and 0.2. The computational fluid dynamics code ANSYS FLUENT is employed to carry out these calculations. The temperature profile inside the silicon ingot during irradiation is of significant importance for uniform doping. Therefore, the impact of Rayleigh number and dimensionless clearance ratio ζon the radial and axial temperature profiles through the ingot is reported. A best estimate correlation for the silicon irradiation facility global Nusselt number in terms of Rayleigh and dimensionless clearance ratio is presented. The dimensionless clearance ratio ζvalue of 0.05 gives the best thermal hydraulic performance. Comparison with the available experimental correlations in the literature shows good agreement.

Abstract: This study deals with a repairable system with N failure modes and K standby unit. Using separation of variable method by solving linear ordinary differential equation for system equations [...]

Prevention of allograft rejection often requires lifelong immune suppression, risking broad impairment of host immunity. Nonselective inhibition of host T cell function increases recipient risk of opportunistic infections and secondary malignancies. Here we demonstrate that AJI‐100, a dual inhibitor of JAK2 and Aurora kinase A, ameliorates skin graft rejection by human T cells and provides durable allo‐inactivation. AJI‐100 significantly reduces the frequency of skin‐homing CLA+donor T cells, limiting allograft invasion and tissue destruction by T effectors. AJI‐100 also suppresses pathogenic Th1 and Th17 cells in the spleen yet spares beneficial regulatory T cells. We show dual JAK2/Aurora kinase A blockade enhances human type 2 innate lymphoid cell (ILC2) responses, which are capable of tissue repair. ILC2 differentiation mediated by GATA3 requires STAT5 phosphorylation (pSTAT5) but is opposed by STAT3. Further, we demonstrate that Aurora kinase A activation correlates with low pSTAT5 in ILC2s. Importantly, AJI‐100 maintains pSTAT5 levels in ILC2s by blocking Aurora kinase A and reduces interference by STAT3. Therefore, combined JAK2/Aurora kinase A inhibition is an innovative strategy to merge immune suppression with tissue repair after transplantation. Targeting JAK2 and Aurora kinase A with a small molecule inhibitor aligns selective immune suppression and tissue repair after transplantation by supporting human regulatory T cells and type 2 innate lymphoid cells.

Ever-Growing supply chain challenges and disruptions directly or indirectly impact all industries. The global pandemic and war situations have caused a significant imbalance in the demand and supply of goods and services worldwide. These horrendous situations elevated the need for more effective supply chain management strategies. Intelligent systems and tech-led solutions are noticeably transforming almost every industry worldwide, and the supply chain and logistics sectors are facing the most significant impact. Many companies worldwide are investing heavily in intelligent supply chain management solutions to address modern global challenges.

Maternal morbidity and mortality continue to rise, and pre-eclampsia is a major driver of this burden1. Yet the ability to assess underlying pathophysiology before clinical presentation to enable identification of pregnancies at risk remains elusive. Here we demonstrate the ability of plasma cell-free RNA (cfRNA) to reveal patterns of normal pregnancy progression and determine the risk of developing pre-eclampsia months before clinical presentation. Our results centre on comprehensive transcriptome data from eight independent prospectively collected cohorts comprising 1,840 racially diverse pregnancies and retrospective analysis of 2,539 banked plasma samples. The pre-eclampsia data include 524 samples (72 cases and 452 non-cases) from two diverse independent cohorts collected 14.5 weeks (s.d., 4.5 weeks) before delivery. We show that cfRNA signatures from a single blood draw can track pregnancy progression at the placental, maternal and fetal levels and can robustly predict pre-eclampsia, with a sensitivity of 75% and a positive predictive value of 32.3% (s.d., 3%), which is superior to the state-of-the-art method2. cfRNA signatures of normal pregnancy progression and pre-eclampsia are independent of clinical factors, such as maternal age, body mass index and race, which cumulatively account for less than 1% of model variance. Further, the cfRNA signature for pre-eclampsia contains gene features linked to biological processes implicated in the underlying pathophysiology of pre-eclampsia.

The main objective of the geometric design consistency is to minimize the emergence of unforeseen events when road users drive along a road segment. A consistent highway design ensures that successive geometric elements act in a coordinated way. In India, vehicles with diverse static and dynamic characteristics interact with each other leading to a significant difference in traffic flow operations compared to highways in developed countries. Due to the heterogeneity in traffic flow, geometric consistency would vary significantly by vehicle category for similar curve characteristics. The present study analyzes geometric design consistency by vehicle and develops vehicle category-based design consistency models for mixed traffic environments on two-lane rural highways in hilly terrain in India. A total of 30 curves with varying geometric characteristics located along the National Highway (NH-953) connecting Netrang and Rajpipla, Gujarat, India, were selected. Speed data were collected using radar gun for three vehicles category: motorized two-wheelers (MTW), cars, and heavy commercial vehicles (HCV). Geometric design consistency was evaluated using operating speed as a surrogate safety measure. The results showed that 38% and 10% of the curves (for cars), 51% and 20% of the curves (for MTW), and 32% and 51% of the curves (for HCV) have ratings of fair and poor consistency, respectively. Design consistency models for different vehicle categories were developed using the generalized linear regression modelling (GzLM) technique. The results showed that the deflection angle is positively correlated, whereas curve and tangent lengths are negatively correlated with highway alignment design consistency.

This paper introduces realistic acceleration profiles for light-duty vehicles departing from rest at two-way stop-controlled (TWSC) intersections where minor roads (controlled by stop signs) intersect with uncontrolled major roads. The new profiles are based on current vehicle characteristics and driver behavior patterns. They are established based on actual field data collected using global positioning system data loggers that recorded the positional and speed data of various experimental vehicles starting from rest at TWSC intersections. Acceleration profiles are established in this paper and are used to develop a revised method for calculating the departure sight distance at TWSC intersections. Design tables were created to provide realistic sight distance values at TWSC intersections for different design speeds and number of lanes on the major road. It was found that the current values of intersection sight distance suggested by the design guides may be inadequate. Such values may force some approaching drivers on the major road to reduce their speeds or move to different traffic lanes to avoid conflicting with the departing vehicles. These maneuvers may have negative impacts on traffic safety. Therefore, implementing the revised method for calculating intersection sight distance, as presented in this paper, may ultimately reduce traffic collisions at TWSC intersections.

Mobility, safety, and environmental sustainability are priorities in the geometric design of roundabouts. This paper presents a multi-objective optimization model that determines the geometric design elements of single-lane roundabouts using all three objectives. The user can specify weights for the objectives, or the model can determine the optimal weights. Mobility is defined in terms of roundabout delay and modeled using the United Kingdom empirical model. Safety is modeled in terms of collision frequency based on the methodology of the Highway Safety Manual. Environmental sustainability is represented by vehicle emissions (nitrogen oxides, hydrocarbons, carbon dioxide, and carbon monoxide) and is modeled using the vehicle-specific power methodology. The proposed model directly identifies the optimal geometric dimensions (decision variables) of the roundabout, including entry width, exit width, approach half-width, circulatory width, effective flare length, entry radius, entry angle, and inscribed circle diameter. The input data to the model include traffic data, site conditions, and limitations based on design guidelines. Application of the proposed model is illustrated using two actual roundabouts. The comparison results show that the proposed model provides substantial improvements in safety, mobility, and environmental sustainability compared with existing conditions. In addition, the model requires much less effort to apply compared with the traditional iterative method, and as such should be of interest to highway designers.

Myocardial function was assessed by stress echocardiography in 28 patients before and after successful elective coronary angioplasty. Dobutamine stress echocardiography was performed using up to 40 [mu]g/kg/min, followed by the addition of atropine in 20 patients to achieve 85% of the predicted maximal exercise heart rate. The initial studies were performed 1 day before and the second ones within 3 days (mean 1.3) after angioplasty. Peak heart rates and systolic blood pressures were the same for the 2 studies. The frequency of dobutamine-induced new wall motion abnormalities decreased from 20 (71%) before to 4 (14%) after angioplasty (p

The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na2O - (90 - x) QZ – xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 °C. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV–Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV–1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

A microgrid has emerged for the transformation from centralized into localized electricity generation, which increases the opportunity for renewable-based distributed generators (DGs) applications such as photovoltaic (PV) and wind as well as small-scale conventional generation units. PV and wind integration provides environmental, technical, and economic benefits. However, the low inertia of the PV system and decoupling due to the presence of the power electronics converter in the wind generation system led to a significant declination in the microgrid's inertia, which causes an excessive frequency nadir and a high rate of change of frequency (ROCOF) in the presence of disturbances. The microgrid's inertia can be enhanced by storing or releasing energy within the microgrid. The wind generation system has intrinsic kinetic energy stored in the rotating parts, while the PV system's sorted energy is improved by introducing an external supercapacitor on the DC link. The aforementioned energy storage elements provide limited energy resources, which should be employed in a proper manner. This article proposes a control scheme to boost the cooperation of wind and PV generation systems for the enhancement of inertia and frequency support. Therefore, the proposed scheme prevents excessive stress on individual generators and improves the utilization of available energy resources. For example, at load increase by 0.5 MW, with frequency support using PV only or wind only, the frequency deviation is enhanced by 44.4 % and 29.5 %, respectively. While for both PV and wind support the frequency simultaneously, the frequency deviation is enhanced by 53.3 %. In addition, with the cooperation of PV and wind, the required energy from PV and wind is reduced by 29.5 % and 13.7 % respectively and the rate of change of frequency is enhanced by 61.9 %. The energy share among PV and wind generation systems is investigated and verified by simulations; tuning formulas are also developed to attain predefined energy support with equal energy sharing among different resources. For instance, with a non-equal energy share strategy and load increases by 0.5 MW, the wind delivers almost 1.6 times the energy delivered from the PV. Hence, more stress occurs on the wind generation compared to PV. While, using equal energy share strategy, the required energy from wind is about 1.03 times the energy delivered from the PV. The proposed control scheme is applied to an AC microgrid that comprises a thermal generation plant, a PV generation system, and a doubly-feed induction generator-based wind generation system. To verify the effectiveness of the proposed scheme, different simulation cases considering load change, wind speed variation, irradiance variations, and weak grid integration are implemented. When compared to individual frequency support, the proposed scheme provides a superior response.

Supplemental Digital Content is available in the text.

This article proposes a rotor position observer based on a reactive power model reference adaptive system (MRAS) for sensorless direct voltage control (DVC) strategy of the stand-alone brushless doubly fed induction generators (BDFIGs). The proposed MRAS observer is based on the control winding (CW) reactive power and the power winding (PW) field orientation. The suggested new sensorless control method does not require flux computation, which can ensure the simplicity and efficacy of the proposed method. The stability analysis of the new observer is investigated and confirmed with the concept of hyperstability and using Popov’s criterion methodology. The robustness of the new control method is analyzed under parameter uncertainties. Furthermore, comprehensive simulation and experimental results are obtained with a prototype wound-rotor BDFIG. The corresponding results confirm the capability and effectiveness of the proposed sensorless DVC strategy with a good transient behavior under different operating conditions for the stand-alone BDFIG system. Moreover, these results assure that the presented rotor position observer is robust via any machine parameter change.

This paper addresses the manipulation of structural, morphology, optical and magnetic properties of LiCo0.25Zn0.25Fe2O4ferrite via incorporation of different proportions of La3+at the expense of iron ions using a sol-gel method. The samples were characterized using the X-ray diffraction technique (XRD), Fourier transform infrared (FT-IR) spectroscopy, the energy dispersive X-ray spectra (EDX), inductively coupled plasma optical emission spectroscopy (ICP-OES), high resolution scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, ultraviolet-diffuse reflectance spectroscopy (UV-DRS), and vibrating sample magnetometer (VSM) technique. The Rietveld refinements of the samples indicate that at higher concentrations of La3+, nanostructures with dual phase, i.e. cubic spinel and orthorhombic LaFeO3perovskite with space group (Pbnm) appear. Optical studies show that the energy band gap (Eg) of the bare LiCo0.25Zn0.25Fe2O4ferrite sample (2.18 eV) reaches up to 2.47 eV at x = 0.06 and above this concentration, it drops sharply to 2.00 eV. Although the saturation magnetization and the coercivity of LiCo0.25Zn0.25LaxFe2–xO4are lower than that of LiCo0.25Zn0.25Fe2O4NPs. Overall, the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo0.25Zn0.25LaxFe2-xO4NPs are suitable to be applied in transformers core.

Supplemental Digital Content is available in the text.

La autoeficacia y expectativa de resultados son constructos teóricos que explican muchos cambios de conductas en salud, como la práctica de ejercicios de suelo pélvico (ESP) y son predictores de adherencia. Las mujeres en tratamiento por cáncer ginecológico presentan distintos grados de disfunción de suelo pélvico que pueden prevenirse con la práctica de ejercicios. El éxito de este tipo de intervenciones depende de la adherencia a ellos. Hay escasez de instrumentos de autoeficacia en idioma español desarrollados en el contexto de intervenciones preventivas.

ABSTRACTIntegrating renewable energy sources (RES) with energy storage systems (ESSs) has become an efficient solution to supply sustained electrical power to isolated loads with better quality. An improvement verification of a standalone wind-driven generator system (WDGS) integrated with a battery storage system (BSS) is presented in this paper. An enhanced maximum power point tracking technique (MPPTT) used for WPGS is presented first. Then, operation of the battery is moderated using a battery control unit which supervises the different modes of operation and ensures a constant dc-bus voltage under different circumstances such as variable wind speed and loading events. Thirdly, a variable modulation index technique is suggested for load voltage regulation in terms of both rms and frequency. Finally, a control strategy for managing the power flow is suggested with an examination based on both generated and consumed powers and the BSS state-of-charge (SOC). An experimental setup has been established to investigate the effectiveness of the proposed control approach during several circumstances. Comprehensive simulation and experimental proofs have demonstrated the competence of developed management strategy to extract the maximum power along with a steady load voltage and frequency (V&f).