Side Ratio Research Articles

Numerical investigation on cooling performance of multilayer pyramid thermoelectric module

A three-dimensional study on the cooling performance of thermoelectric module consisting of multilayer pyramid thermoelectric legs is investigated numerically. Two physical models were established for comparison, which are rectangular shaped and multilayer pyramid thermoelectric cooling modules, respectively. This study mainly focuses on the effect of leg height, side ratio and the number of leg layers on the cooling performance of thermoelectric module. Generally, the obtained results showed that the multilayer pyramid module has better cooling performance than that of rectangular shaped module. By increasing the values of side ratio and the number of layers, the maximum reduction of the minimum averaged temperature of cold surface reaches 11.25 K compared to the rectangular shaped module. It is also observed that when the values of side ratio and the number of leg layers are low such as 1.5 and 1, the multilayer pyramid module has not very good cooling performance. Finally, a recommended map on the multilayer pyramid module is presented according to side ratio and the number of leg layers for the different heights of thermoelectric legs to evaluate the cooling performance.

Compound super-oscillation lens for reflective confocal imaging

The super-oscillation lens (SOL) can achieve super-resolution focusing but have to trade-off with weaker hotspots and higher sidebands. We propose a single compound SOL to achieve reflective confocal imaging in principle without additional lenses. The designed SOL consists of an outer lens and an inner lens which play the role of focusing lens and collective lens respectively. As a result, focusing and collecting functions can be simultaneously realized. The improved system can achieve excellent imaging performance with an ultra-high resolution (<0.314λ/NA, NA stands for numerical aperture), and almost negligible side lobe ratio and no side bands, which proved superior to conventional laser scanning confocal microscopy and single SOL. This technology can be attractive for a variety of applications in super-resolution imaging and biomedical sciences.

Triggering of galloping in structures at low Reynolds numbers

The fundamental mechanisms that are important for the triggering of galloping in a flow-induced vibration (FIV) system consisting of the flow past an elastically-mounted body (D-section, isosceles-triangular, rectangular) is investigated in this paper using three key-enabling methodologies: namely, high-fidelity full-order model/computational fluid dynamics simulations, modal analysis based on the determination of an data-driven model using the eigensystem realization algorithm, and use of the Den Hartog stability (galloping) criterion for the assessment of the aerodynamically unstable behavior of the system obtained from classical quasi-steady theory. The synthesis of the results from the application of these three key-enabling technologies is used to study the effect of the Reynolds number Re, the mass ratio m∗, the cross-sectional geometry and the angle of attack of the incident wind direction relative to the orientation of the elastically-mounted body on the suppression or initiation of galloping. In the application of data-driven modal analysis to a FIV system with coupled modes, the importance of identifying correctly which of the coupled modes correspond to the structure mode (SM) possibly taking into account mode switching is stressed, and the failure to do so is shown to lead to a significant underestimation of the value of the reduced velocity Ur associated with the onset of galloping. The range of values of Ur where the SM is positive is related to the flutter lock-in regime for smaller values of Ur (typically for Ur≤7) and to the galloping regime for the larger values of Ur (typically for Ur≥10). The application of data-driven modal analysis to a FIV system shows that increasing Re and decreasing m∗ has two effects: namely, enhancement of the coupling between the structure and wake modes and increases of the range of Ur values where the SM exhibits a positive growth rate. Data-driven modal analysis and the Den Hartog stability criterion is applied to explain the recently observed phenomenon of the collapse of galloping for a rectangular cylinder when the side ratio is decreased below a critical threshold value (between about 0.1 and 0.2). It is shown that galloping appears and disappears when the flat face of a body in directed into (windward of) or away from (leeward of) the incident wind direction. An investigation of the effects of the cross-sectional geometry of the body on the triggering of soft- or hard-galloping is undertaken.

Wind-Induced Responses and Wind Loads on a Super High-Rise Building with Various Cross-Sections and High Side Ratio—A Case Study

With the development of construction technology and material, more and more super high-rise buildings will be constructed in the future. In a specific metropolitan area, super high-rise building with various cross-section and high side ratio have to been designed and constructed due to the size limitation of construction site. This kind of building is also very prone to wind excitations. In this research, wind tunnel tests for a practical case of this kind of building with surrounding buildings were carried out in atmospheric boundary wind tunnel. Equivalent static wind loads (ESWLs), wind-induced responses and wind load distribution on the building were analyzed. In particular, the base overturning moment along the axis with weak lateral stiffness were investigated for bearing capacity limit state design of the building. The results demonstrate that the maximum value of wind-induced base overturning moments and acceleration responses appears at 60° or 330° wind directions instead of the orthogonal wind direction, and the aerodynamic interference of surrounding buildings affects the wind pressure distribution on facades of the building. These results and conclusion may be helpful to wind-resistant design of super high-rise buildings with high side ratio.

Abstract WP112: Iodine-123-iomazenil Spect Revealed Recovery Of Neuronal Viability In Association With Improvement Of Cognitive Dysfunction After Revascularization In Moyamoya Disease

Background: Recent studies indicate 123I-iomazenil (123I-IMZ) SPECT could demonstrate a neuronal viability. Although cognitive dysfunction has been recognized as an important issue in adult moyamoya disease (MMD), standard neuroradiological methods to define such condition are not established. Aim: Relationship between cognitive function and 123I-IMZ SPECT before and after revascularization in MMD was firstly examined. Method: Fifteen patients whose cerebrovascular reactivities (CVRs) were decreased only on the treatment sides were studied. Cognitive function was examined using mini-mental scale examination (MMSE, cutoff 27) and frontal assessment battery (FAB, cutoff 16) before and 6 months after surgery. 123I-IMZ and 123I-iodoamphetamine SPECT with acetazolamide challenge were performed at the same timings. Radioreactivities of 123I-IMZ SPECT at the regions with decreased CVR were investigated using affected-to-contralateral side ratio (ACR). Results: Eleven patients showed normal cognitive dysfunction before surgery (MMSE 29.5, FAB 18). In their preoperative 123I-IMZ SPECT, there were no regions with decreased uptakes (ACR 0.97). The cognitive functions and 123I-IMZ SPECT were not worsened after surgery (MMSE 29.9, FAB 18, ACR 0.99). By contrast, preoperative images of four patients with cognitive dysfunction (MMSE 23.8, FAB 14) showed decrease of 123I-IMZ uptakes, and the preoperative ACRs (0.82) were significantly lower than those of the normal group. Cognitive functions and 123I-IMZ uptakes of these four patients tended to ameliorate after revascularization (MMSE 27.5, FAB 15.5, ACR 0.92). Conclusion: Cognitive functions of MMD patients were associated with 123I-IMZ uptakes, and could improve after surgery with recoveries of neuronal viabilities.

Эффективность невролиза плечевого сплетения под видеоэндоскопической ассистенцией при лечении брахиоплексопатий у взрослых

Introduction The method of endoscopic revision, neurolysis and decompression of the brachial plexus is a current minimally invasive method of treatment. It is able to completely preserve the anatomical structures (skin, fascia, muscles, clavicle, arteries, veins, nerves) and minimize damage to the structures of the brachial plexus, since neurolysis is carried out along the trunks and bundles of the plexus through a low-invasive transaxillary approach. However, the effectiveness of this type of operation has not been studied previously. The aim of the study To evaluate the effectiveness of brachial plexus neurolysis under video endoscopic assistance in the treatment of brachioplexopathies in adults Materials and methods The study involved patients hospitalized in the Tyumen Federal Center for the period from 2017 to 2022 with a diagnosis of brachial plexus palsy, who, for medical reasons, underwent neurolysis of the brachial plexus under video endoscopic assistance. The number of patients gave informed concent was 25 subjects. The results of treatment were assessed with score systems and questionnaires; neurological examination was performed and muscle strength was assessed according to the British scale (M5-M0), the type of sensory disorders and their degree on a scale from 0 to 10, where 10 is the complete preservation of sensitivity, and 0 is its complete absence and were confirmed by the data of functional diagnostics (stimulation ENMG) 3, 6 and 12 months after the operation. Statistical data processing was carried out using the Microsoft Excel (Microsoft Office 365) and Stattech 2.0 software package. For quantitative traits, the arithmetic mean (M) and standard error of the mean (SEM) were calculated. To assess the statistical significance of the results obtained, the parametric t-Student's test was used. Differences were considered significant at p &lt; 0.05. Results The mean age of the patients was 48 ± 15 years, gender ratio (m/f) was 18/7, the affected side (right/left) ratio was 12/13. A positive result was achieved in 75 % of cases (n = 19), the absence of positive dynamics was noted in 25 % of cases (n = 6); there were no cases of poor results. When comparing the indicators in groups with a positive result and its absence, it was revealed that the degree of limb dysfunction and the degree of paresis affect the treatment outcome (p &lt; 0.05). In all patients with a positive result, a positive trend was observed starting from 5.89 ± 0.93 (range 1-15) weeks after surgery. Conclusion The proposed method of neurolysis of the brachial plexus is an effective method for the treatment of patients with brachial plexus palsy of various etiologies. The main factor influencing the outcome of reatment is limb dysfunction, the severity of which is inversely proportional to the function recovery in the postoperative period. Based on the results obtained, neurolysis was not effective in paresis of the affected muscles scoring 0-1 points. If there is no positive effect from the intervention within 3 months after its implementation, further waiting tactics is not advisable. Other treatment options should be considered.

Low-power consumption InP-based optical phase arrays with non-uniformly spaced output waveguides.

Optical Phase Arrays (OPAs) are expected to be an ideal solution to achieve beam shaping, laser radar (LIDAR), free-space optical communications, and spatially resolved optical sensors, etc. We demonstrated a low-power consumption 32-channel OPA with non-uniformly spaced waveguides based on InP substrate. The phase shifters are based on a p-i-n structure which are operated with reverse bias and have a low power consumption. Besides, in order to improve the performance especially to obtain larger steering angle and narrower beam divergence without increasing the number of channels, we have optimized the spacing between the output waveguides. The fabricated OPA achieved a steering angle of 35° with the side lobe suppression ratio more than 8.2 dB across the angle range from -20° to 20° in the far field, which is the largest phase tuning steering angle reported by InP-based OPAs as far as we know. The divergence angle is about 0.46° in the phase steering dimension and the power consumption of the OPA at each steering angle is lower than 7.5 mW.

Multilevel unilateral versus bilateral pedicular percutaneous vertebroplasty for osteoporotic vertebral compression fractures.

Retrospective study. Controversy exists over the need for unilateral vs. bilateral pedicular percutaneous vertebroplasty (PVP) for patients with osteoporotic vertebral compression fractures (OVCFs). Clinical research is scarce comparing two approaches for multi-level PVP. This study aimed at evaluating the clinical and radiographic outcomes of multi-level PVP using two approaches for OVCFs. Seventy-eight patients with OVCFs undergoing multi-level PVP were enrolled including 36 patients undergoing unilateral PVP and 42 undergoing bilateral PVP. The clinical and radiological assessments including the Visual Analogue Scale (VAS), sagittal and coronal segmental Cobb, vertebral compression ratio (VCR), and vertebral sides ratio (VSR) were evaluated preoperatively and postoperatively. All patients achieved a minimum 2-year follow-up. A total of 164 fractured vertebrae were enrolled. Regarding clinical efficacy, the VAS score improved in both groups after surgery, but the two groups did not differ significantly. The changes tendency in Sagittal Segmental Cobb, VSR, and VCR were similar postoperatively, and no statistically significant difference between groups. As for the Coronal Segmental Cobb angle, patients in unilateral and bilateral groups were shown to have 5.0° ± 4.0° and 2.6° ± 2.2° degrees loss of correction at a minimum 2-years follow-up duration, respectively. The loss of correction in the Coronal Segmental Cobb of unilateral group was significantly greater than that of bilateral group. Both multi-level unilateral and bilateral pedicular PVP achieved significant pain reduction and vertebral height restoration. Moreover, the bilateral PVP has shown advantages in stabilizing Coronal Cobb angle in patients with OVCFs.

On the large amplitude vibration of shallow sandwich shells with FG-GNPRP core considering initial geometric imperfections

The present study investigates the influence of initial geometric imperfections on large amplitude vibration of shallow sandwich shells with functionally graded graphene nanoplatelets reinforced porous (FG-GNPRP) core embedded between two aluminium facets. The aluminium core is reinforced with graphene nano-platelets (GNP) and the effective properties such as elastic modulus, and mass density, etc. are estimated using Halpin-Tsai and Voigt models, respectively. The continuous functions are adopted to accomplish micro-structural gradation while creating pores which imparts the variation in material properties along thickness direction. The nonlinear governing equations based on higher order shear deformation theory and Sander’s approximation are derived using variational approach. The nonlinearity is introduced in von-Kármán sense and various imperfection modes such as sine, global and local types are considered in transverse direction. The nonlinear results are accessed using finite element method in conjunction with direct iterative technique. The influence of porosity, GNP weight fraction, imperfection amplitude, thickness, side, and radius ratios on the vibration response of the sandwich shells is explored in detail.

Comparison of Bayesian Estimation and SVD Methods for CT Perfusion in Patients with Acute Stroke

There are various analysis methods for CT perfusion (CTP). Although the advantages of Bayesian estimation algorithms have been newly suggested, comparisons with other analysis methods on clinical data are still limited. In this study, we compared the Bayesian estimation method with the singular value decomposition (SVD) method in the evaluation of patients with acute cerebral infarction and examined its usefulness. CTP data from 13 patients with acute stroke were analyzed using the SVD and Bayesian estimation methods implemented in Vitrea. Evaluation of visual clarity of the ischemic area and quantitative values of the healthy side-affected side ratio using the mean values of the left and right region of interest (ROI) on the images were compared using the SVD and Bayesian estimation methods. In visual evaluation, there were significant differences in CBV in four cases, and in CBF, MTT, and TTP in many cases. The healthy side-affected side ratio of the SVD and Bayesian estimation methods were as follows: CBF 1.19, 1.84; CBV 1.09, 1.02; MTT 1.12, 1.79; and TTP 1.48, 1.19. For CBF and MTT, the Bayesian estimation method had a larger ratio of the healthy side to the affected side, and for TTP, the SVD method had a larger ratio of the test side to the affected side. We suggest that the Bayesian estimation method is more useful than the SVD method for assessing CBF and MTT in CTP analysis of patients with acute stroke.

Automatic Detection of CFRP Subsurface Defects via Thermal Signals in Long Pulse and Lock-In Thermography

Thermography is widely used to detect delamination defects in carbon fiber reinforced plastics (CFRP). This paper proposes a model to detect defects automatically by extracting the thermal signal characteristics of CFRP materials. An optically excited thermography system is constructed for pulsed and lock-in thermography experiments to compare thermal signal data sets in different excitation modes. A multi-task joint loss function is defined to train the model for defect detection and depth prediction. The effects of different attention modules (AM) are analyzed to improve the model performance. By comparing the effects of traditional thermography processing methods and methods based on Convolutional Neural Network (CNN), it is found that the proposed model can detect defects with minimum aspect ratio (ratio of short side to depth) of 2.5, and the relative error percentage in depth prediction is below 10%.

Effect of organic solvents on calcium minodronate crystal morphology in aqueous solution: an experimental and theoretical study.

The influence of nine organic solvents on the crystal morphology of calcium minodronate (Ca(Min)2) was investigated by experimental investigations and molecular simulations. Hirshfeld analysis was used to reveal the intermolecular interactions, and the modified attachment energy (AE) model was applied to constructing the Ca(Min)2-organic-water model in different organic-water solvents. The surface structure and the mass density profile were demonstrated and analyzed. The results showed that there were different adsorption conditions in different organic-water solvents. Furthermore, it was found that the (2 0 0)/(1 1 0) side ratio of Ca(Min)2 crystal had a linear relationship with the volume of organic solvent and had a certain correlation with some solvent properties. It is believed that the research developed in this work could have a promising application in prediction of Ca(Min)2 crystal morphology and could give guidance in the selection of organic solvents to control the desirable crystal morphology.

Refined prediction of crosswind forces on rectangular tall buildings with different side ratios

The crosswind responses of tall buildings are complicated due to numerous influencing factors. However, the relevant codes for estimating the crosswind responses have a limited application scope and the corresponding empirical formulas may cause inaccurate assessment of structural responses due to the fitting errors. This study aims to achieve more accurate and flexible predictions of the crosswind forces and wind-induced responses of rectangular tall buildings in comparison with using the conventional empirical formulas. A series of high-frequency force balance (HFFB) tests was conducted on rectangular tall buildings with side ratios from 0.2 to 5 to investigate the crosswind force spectra and the root mean square (RMS) base moment coefficients in two terrain categories. The crosswind force spectra and the crosswind responses of the structure were predicted by using the new proposed formulas and genetic algorithm-backpropagation (GA-BP) neural network, respectively. The results showed that the RMS crosswind base moment coefficients of rectangular tall buildings generally increase with the increase in the side ratio, and can be expressed as piecewise functions related to the side ratio. The proposed formulas can effectively predict the crosswind force spectra of rectangular tall buildings with different side ratios. Compared with the traditional nonlinear fitting method, the GA-BP neural network has higher fitting accuracy and stronger ability for extrapolation prediction. Combined with the random vibration theory, the GA-BP neural network can accurately predict the crosswind responses of rectangular tall buildings. By comparing with the relevant codes, it shows that the crosswind responses of rectangular tall buildings under different side ratios are overestimated to different degrees by GB 50009-2012.

Further predictive value of lymphovascular invasion explored via supervised deep learning for lymph node metastases in breast cancer

Lymphovascular invasion, specifically lymph-blood vessel invasion (LBVI), is a risk factor for metastases in breast invasive ductal carcinoma (IDC) and is routinely screened using hematoxylin-eosin histopathological images. However, routine reports only describe whether LBVI is present and does not provide other potential prognostic information of LBVI. This study aims to evaluate the clinical significance of LBVI in 685 IDC cases and explore the added predictive value of LBVI on lymph node metastases (LNM) via supervised deep learning (DL), an expert-experience embedded knowledge transfer learning (EEKT) model in 40 LBVI-positive cases signed by the routine report. Multivariate logistic regression and propensity score matching analysis demonstrated that LBVI (OR 4.203, 95% CI 2.809-6.290, P<0.001) was a significant risk factor for LNM. Then, the EEKT model trained on 5780 image patches automatically segmented LBVI with a patch-wise Dice similarity coefficient of 0.930 in the test set and output counts, location, and morphometric features of the LBVIs. Some morphometric features were beneficial for further stratification within the 40 LBVI-positive cases. The results showed that LBVI in cases with LNM had a higher short-to-long side ratio of the minimum rectangle (MR) (0.686 vs. 0.480, P=0.001), LBVI-to-MR area ratio (0.774 vs. 0.702, P=0.002), and solidity (0.983 vs. 0.934, P=0.029) compared to LBVI in cases without LNM. The results highlight the potential of DL to assist pathologists in quantifying LBVI and, more importantly, in exploring added prognostic information from LBVI.

Proton-Exchange Membrane Fuel Cell Balance of Plant and Performance Simulation for Vehicle Applications

In this study, a newly developed zero-dimensional electrochemical model was used for modeling and controlling proton-exchange membrane fuel cell (PEMFC) performance. Calibration of the model was performed with measurements from the fuel cell stack. Subsequently, a compressor and a humidifier on the cathode side were sized and added to the existing model. The aim of this work was to model the PEMFC stack and balance of plant (BoP) components in detail to show the influence of operating parameters such as cathode pressure, stack temperature and cathode stoichiometric ratio on the performance and efficiency of the overall system compared to the original model using a newly developed real-time model. The model managed to predict the profile of essential parameters, such as temperature, pressure, power, voltage, etc. The most important conclusions from this particular case are: the cell power output is only slightly changed with the variations in stoichiometric ratio of the cathode side and adding an external compressor is valid only for high current applications, but in those cases, there is 10–22% power gain. Stack temperature is a very influential parameter. Optimal temperatures were determined through design of experiments (DoE) and for this case are in the 40–60 °C range, where for low current applications lower temperatures are better due lower activation loss (8% difference between 80 °C and 40 °C at 20 A current). For high current applications, due to lower ohmic losses, higher temperatures are desirable.

Spanwise correlation and coherent structures of separated flow around rectangular 5:1 cylinder

Spanwise correlation and coherent structure of separated flow around a rectangular cylinder with a side ratio of B/D = 5 (B: breadth; D: depth of cylinder) are numerically investigated by Large Eddy Simulation (LES) at Reynolds number Re = 22,000. The investigation utilizes one series of three-dimensional simulations with various spanwise lengths up to 10D at a grid resolution of D/16 and another series of simulations with various spanwise grid resolutions as small as D/40 at a spanwise length of 5D, in addition to a two-dimensional simulation. The results show that a spanwise coherent flow structure with a wavelength of roughly 1.4D, associated with longitudinal vortices, exists in the separated flow. A spanwise length of 3D seems long enough to eliminate the influence of spanwise coherent flow structure on the global aerodynamic parameters and leads to convergent simulation results. The spanwise correlations of sectional forces and surface pressures decay with the spanwise distance. A finer spanwise resolution results in decreased spanwise correlations in the investigated spanwise resolution region. The results also imply that it is necessary to consider the combined effects of multiple interacting factors such as numerical method, three-dimensional grid discretization and turbulence model when selecting the spanwise resolution.

Vortex-induced vibrations of a rectangular cylinder

Vortex-induced vibrations (VIV) of an elastically mounted rectangular cylinder with one degree of freedom immersed into viscous incompressible uniform flows have been researched via the lattice Boltzmann method. The Reynolds number is fixed at 100, the mechanical damping is set to zero and the reduced velocity is varied between 1 and 16. Results demonstrate that both side ratio and mass ratio have significant influences on the behaviours of fluids and structures. Resonance can be excited extensively and its region extends with decreasing side ratio and mass ratio. In the region of low side ratio and mass ratio, a phenomenon of vibration frequency shift usually happens and even though the structure leaves the resonance region, the cylinder still undergoes a large-amplitude oscillation. A total of three distinct vortex wake modes are observed. Mechanistic analysis indicates that the shift of oscillation frequency is induced by the competition between wake mode and structure mode and large-amplitude vibrations in the resonance region will be caused by the power transfer between fluids and structures. The excitation of wake mode is associated with the cylinder shape and response amplitude. Meanwhile, the process of vortex formation has significant influences on the cylinder motion.

Two nomograms based on radiomics models using triphasic CT for differentiation of adrenal lipid-poor benign lesions and metastases in a cancer population: an exploratory study.

To investigate the effectiveness of CT-based radiomics nomograms in differentiating adrenal lipid-poor benign lesions and metastases in a cancer population. This retrospective study enrolled 178 patients with cancer history from three medical centres categorised as those with adrenal lipid-poor benign lesions or metastases. Patients were divided into training, validation, and external testing cohorts. Radiomics features were extracted from triphasic CT images (unenhanced, arterial, and venous) to establish three single-phase models and one triphasic radiomics model using logistic regression. Unenhanced and triphasic nomograms were established by incorporating significant clinico-radiological factors and radscores. The models were evaluated by the receiver operating characteristic curve, Delong's test, calibration curve, and decision curve. Lesion side, diameter, and enhancement ratio resulted as independent factors and were selected into nomograms. The areas under the curves (AUCs) of unenhanced and triphasic radiomics models in validation (0.878, 0.914, p = 0.381) and external testing cohorts (0.900, 0.893, p = 0.882) were similar and higher than arterial and venous models (validation: 0.842, 0.765; testing: 0.814, 0.806). Unenhanced and triphasic nomograms yielded similar AUCs in validation (0.903, 0.906, p = 0.955) and testing cohorts (0.928, 0.946, p = 0.528). The calibration curves showed good agreement and decision curves indicated satisfactory clinical benefits. Unenhanced and triphasic CT-based radiomics nomograms resulted as a useful tool to differentiate adrenal lipid-poor benign lesions from metastases in a cancer population. They exhibited similar predictive efficacies, indicating that enhanced examinations could be avoided in special populations. • All four radiomics models and two nomograms using triphasic CT images exhibited favourable performances in three cohorts to characterise the cancer population's adrenal benign lesions and metastases. • Unenhanced and triphasic radiomics models had similar predictive performances, outperforming arterial and venous models. • Unenhanced and triphasic nomograms also exhibited similar efficacies and good clinical benefits, indicating that contrast-enhanced examinations could be avoided when identifying adrenal benign lesions and metastases.

OPTIMAL SUPPORT POSITIONING OF A RECTANGULAR PLATE IN A STABILITY PROBLEM UNDER TEMPERATURE FIELD EXPOSURE

Introduction . Thin plates are widely used structural elements in modern civil, mechanical, aeronautical, and marine engineering design. Alongside the temperature field, the middle plain of plates is subjected to uniformly distributed normal mechanical forces, with σφ intensity, which raises the stability problem of thin plates. The strength and stability of rectangular plates have been investigated by S.P. Timoshenko [1], S.A. Ambartsumyan [2] and others. In the field of design of thin structure elements, the optimal positioning of plate supports has been studied in the works of V.Ts. Gnuni [3], M.V. Belubekyan [4], and A.V. Eloyan [5, 6]. However, the problem of optimal support positioning has not been sufficiently studied, particularly regarding the thermoelastic stability of thin plates. The simultaneous exposure of mechanical forces and temperature field on a rectangular plate poses the issue of an efficient parameter с that determines the positions of transverse supports along the length of a plate thus ensuring the maximum buckling load. Aim . To calculate the optimal values of a parameter α = c/a in accordance with σ̅, h̅, values for different side ratios λ=a/b of a plate for specified temperature values. Materials and methods . Elastic isotropic plates were used, the maximum buckling load was determined. Results and conclusions . According to the results, the optimal location of plate supports for values λ = a/b–1/2,1 is determined by σ̅ = 3 β depending on the plate temperature. The maximum buckling load is determined when σ̅ = 3 β , h̅ = 0,01, w* = 1,772, α = 0,37, Т = 300 °С.

Fetal Cardiac Inflow Characteristics in Response to Fetal Anemia: Based on Fetal Hemoglobin Bart's Disease at Mid-Pregnancy.

To identify the inflow (filling time fraction [FTF] and E/A ratio) characteristics of fetuses with anemia, and to evaluate the performance of the inflow markers in predicting the affected fetuses. Fetuses at risk of hemoglobin (Hb) Bart's disease at 17-22 weeks were prospectively recruited to undergo echocardiography before diagnostic cordocentesis. Cardiac Doppler images were digitally stored for off-line blinded measurements of FTF and E/A ratio. A total of 428 fetuses at risk of Hb Bart's disease were analyzed, including 88 affected fetuses (20.6%). The mean gestational age at the time of diagnosis was 19.43 ± 1.5 weeks. The FTFs in both sides were significantly lower in the affected fetuses, whereas the E/A ratios of both sides were significantly higher in the affected group. According to the receiver operating characteristic curves, the performance of the FTF of the right side in predicting affected fetuses was slightly better than that of the left side (area under curve: 0.707 versus 0.680, P < .001). Likewise, the performance of the E/A ratio of the tricuspid valve was slightly better than that of the mitral valve. Also, FTF was superior to E/A ratio in predicting the affected fetuses. New insights leading to a better understanding of the fetal cardiac response to anemia are: 1) the FTFs in both sides were significantly decreased, suggesting some degree of diastolic ventricular dysfunction; 2) the E/A ratios of both sides were significantly increased, indicating volume load; and 3) The inflow parameters may be useful as a new predictor of fetal anemia, especially among pregnancies at risk.