Analysis and study of two‐dimensional parameter bifurcation of wind power farms and composite loads

This study focuses on the stability of power system based on codimension‐two bifurcation theory. In this paper, we investigate the impact of load modeling on permissible wind power generation margins in distribution networks. The study considers codimension‐two bifurcations of equilibria and limit cycles in wind power systems depending on varying two parameters simultaneously. The principle parameter is the wind power generation, and the other parameter depends on the different types of loads. The types of loads are ZIP, exponential recovery, dynamic induction loads, and composite load models. To study the effects of the induction motor loads, the proportion of the static component in the motor load is changed and assessed with respect to their mechanical loads. Wind generation margin boundaries are traced, and saddle‐node, Hopf, and limit‐induced bifurcation branches are obtained, delimiting the stable and unstable operating regions in the parameter space. The analysis presented in this paper can pave the way for determining methods for improving and monitoring these margins with consideration to the system parameters and load composition.     

Heat transfer due to electroosmotic flow of viscoelastic fluids in a slit microchannel

The bio-microfluidic systems are usually encountered with non-Newtonian behaviors of working fluids. The rheological behavior of some bio-fluids can be described by differential viscoelastic constitutive equations that are related to PTT and FENE-P models. In the present work, thermal transport characteristics of the steady fully developed electroosmotic flow of these fluids in a slit microchannel with constant wall heat fluxes have been investigated. The Debye–Huckel linearization is adopted and the effects of viscous dissipation and Joule heating are taken into account. Analytical solutions are obtained for the transverse distributions of velocity and temperature and finally for Nusselt number. Two different behaviors are observed for the Nusselt number variations due to increasing ?_geWe² which are an increasing trend for positive wall heat flux and a decreasing one for negative wall heat flux. However, the influence of ?_geWe² on Nusselt number vanishes at higher values of the dimensionless Debye–Huckel parameter. It is also realized that the effect of viscous heating is more important at small values of both ?_geWe² and the dimensionless Debye–Huckel parameter. Furthermore, the results show a singularity in Nusselt number at higher negative values of the dimensionless Joule heating parameter.     

Ventricular tachycardia during repair of gastroschisis

This questionnaire survey of 71 patients with ankylosing spondylitis (members of the National Ankylosing Spondylitis Society of the UK) revealed that a substantial proportion of patients were apparently not told of several aspects of their illness by their doctors such as likely cause(s), familial clustering, role of HLA tissue typing and diet (appropriately). Only a small percentage (4.2%) were counselled to actively seek screening for close family members. As HLA B27 presence is not diagnostic of ankylosing spondylitis, and it cannot be prevented or arrested even if diagnosed at onset or early stages, routine screening of close family members cannot be justified at present.     

Comparison of sonography, sonohysterography, and hysteroscopy for evaluation of abnormal uterine bleeding

We compared transvaginal sonography, sonohysterography, and diagnostic hysteroscopy in the evaluation of abnormal uterine bleeding, Sixty-eight women 40 or older with abnormal uterine bleeding were assigned to undergo either transvaginal sonography or sonohysterography. All subjects then had diagnostic hysteroscopy and endometrial biopsy. Patients with abnormal findings underwent operative hysteroscopy or definitive therapy. Transvaginal sonography, sonohysterography, and diagnostic hysteroscopy revealed a sensitivity of 95%, 90%, and 78%, and a specificity of 65%, 83%, and 54%, respectively. The average cost for transvaginal sonography of sonohysterography was $195 and the cost for diagnostic hysteroscopy was $675. Transvaginal sonography and sonohysterography are cost-effective alternatives and more sensitive diagnostic tests than office diagnostic hysteroscopy.     

Preparation of composite polymer electrolytes by electron beam-induced grafting: Proton- and lithium ion-conducting membranes

Two classes of composite polymer electrolyte membranes, one conducting lithium ions (Li⁺) and the other conducting protons (H⁺) were prepared using simultaneous electron beam-induced grafting. Porous poly(vinylidene fluoride) (PVDF) films were impregnated with styrene and subjected to electron beam (EB) irradiation to obtain polystyrene (PS) filled PVDF precursor films that were subsequently treated with either chlorosulfonic acid/1,1,2,2-tetrachloroethane mixture to obtain H⁺-conducting composite membranes or LiPH₆/EC/DEC liquid electrolyte to obtain Li⁺-conducting composite membranes. The properties of the obtained membranes were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and AC impedance measurements. The obtained membranes were found to achieve grafting content up to 46% with superior Li⁺-conductivity of 1.91 × 10⁻³ S/cm and H⁺-conductivity of 5.95 × 10⁻² S/cm. The results of this work show that simultaneous radiation-induced grafting with EB is a promising method to prepare high quality ion-conducting membranes for possible use in fuel cells and lithium batteries.     

Nickel(II) ion-intercalated MXene membranes for enhanced H2/CO2 separation

Hydrogen fuel has been embraced as a potential long-term solution to the growing demand for clean energy. A membrane-assisted separation is promising in producing high-purity H₂. Molecular sieving membranes (MSMs) are endowed with high gas selectivity and permeability because their well-defined micropores can facilitate molecular exclusion, diffusion, and adsorption. In this work, MXene nanosheets intercalated with Ni²⁺ were assembled to form an MSM supported on Al₂O₃ hollow fiber via a vacuum-assisted filtration and drying process. The prepared membranes showed excellent H₂/CO₂ mixture separation performance at room temperature. Separation factor reached 615 with a hydrogen permeance of 8.35 × 10⁻⁸ mol·m⁻²·s⁻¹·Pa⁻¹. Compared with the original Ti₃C₂T_x/Al₂O₃ hollow fiber membranes, the permeation of hydrogen through the Ni²⁺-Ti₃C₂T_x/Al₂O₃ membrane was considerably increased, stemming from the strong interaction between the negatively charged MXene nanosheets and Ni²⁺. The interlayer spacing of MSMs was tuned by Ni²⁺. During 200-hour testing, the resultant membrane maintained an excellent gas separation without any substantial performance decline. Our results indicate that the Ni²⁺ tailored Ti₃C₂T_x/Al₂O₃ hollow fiber membranes can inspire promising industrial applications.     

Adaptation of the strain measurement in textile reinforced cementitious matrix composites by distributed optical fibre and 2D digital image correlation

The study presented in this paper aims to adapt and calibrate two strain measurement techniques used for textile reinforced cementitious matrix composites (TRCMCs): distributed optical fibres and 2D digital image correlation (DIC). These composites exhibit tensile behaviour characterised by a succession of transverse cracks along specimens. During the tensile test, out-of-plane parasitic displacements may occur due to the geometry of specimens and possible imperfections of the test method. These phenomena interfere with the measurement of the strain sensors, leading to loss of results and parasitic strain. In order to eliminate them and to finely analyse the complex behaviour of TRCMCs, a test methodology and experimental approach are proposed for optical fibres, and a practical and simple solution is proposed to quantify the parasitic strains of the 2D DIC. For optical fibres, Rayleigh backscatter is used, allowing a millimetric spatial resolution and a high recording frequency. For the DIC, required equipment is used, and the results are processed through existing commercial software.     

Buckling behavior of standing laminated Mindlin plates subjected to body force and vertical loading

In this article, an exact analytical solution for stability analysis of vertical moderately thick laminated rectangular plates subjected to selfweight and top load on the basis of the first-order shear deformation plate theory is presented. It is assumed that the symmetric laminated rectangular plate is composed of transversely isotropic layers. Employing an analytical approach, the coupled governing stability equations of the laminated plate are converted into two uncoupled partial differential equations in terms of transverse displacement and an auxiliary function. It is considered that the vertical sides of the laminated plate are simply supported. Using Levy-type solution, the decoupled equations are reduced to two ordinary differential equations. One of these equations has variable coefficients, for which an exact analytical solution is obtained in the form of power series method of Frobenius. After appropriate convergence study, the present analysis is validated by comparing the results with the existing data reported in the literature. Furthermore, the effects of aspect ratio, plate thickness, boundary conditions, weight of plate and top load on the stability of laminated rectangular plates are investigated and discussed in details. The presented formulations and results can be used as benchmark for future research studies.     

Radiolabeling,quality control,and biodistribution of <Superscript>99m</Superscript>Tc-sulfadiazine as an infection imaging agent

Abstract—Sulfadiazine (antibiotic used for treating bacterial infections) was labeled with ^99mTc with the aim of the development of a new radiopharmaceutical for infection imaging. The influence of the reaction parameters such as the substrate and SnCl₂·2H₂O concentrations, pH of the reaction mixture, and reaction time on the labeling yield was examined, and the labeling conditions were optimized. The maximum radiochemical yield of ^99mTc-sulfadiazine (94.7%) was obtained by using 50 µg of SnCl₂·2H₂O and 1 mg of sulfadiazine at pH 5. The radiochemical purity of the labeled compound was evaluated by ITLC and HPLC. The biological distribution of ^99mTc-sulfadiazine in mice with experimentally induced Staphylococcus aureus infection in the right thigh was studied, and the bacterial infected thigh/normal thigh (target-to-nontarget, T/NT) ratio was evaluated. The T/NT ratio for ^99mTc-sulfadiazine was found to be 3.6, which is comparable to the commercially available ^99mTc-ciprofloxacin (3.8), indicating that ^99mTc-sulfadiazine can be used for infection imaging.