Geometric Coefficient Research Articles

Stability Analysis of Construction Factors for Partially Cable-Stayed Bridges with Multiple Towers and High Piers

Partially cable-stayed bridges have the characteristics of continuous rigid-frame bridges and cable-stayed bridges, making them a novel composite bridge system. This study focuses on the construction project of a multi-tower high-pier curved partially cable-stayed bridge to investigate the bridge’s stability during construction. The Midas/Civil software was used to establish a model for key construction stages of the bridge, considering structural linear elasticity and geometric nonlinearity. The study examines the impact of static wind loads, asymmetric construction of the main girder, closure sequence, and the load and detachment of the hanging basket on the bridge’s stability during construction. The results indicate that static wind loads have a significant impact on structural geometric nonlinearity, with a maximum reduction of 4.99%. Asymmetric construction at both ends of the main girder can cause structural instability and should be avoided. The geometric nonlinearity stability coefficient for the hanging basket load decreased by 10.83% during the maximum no-cable stage and by 7.84% during the cable stage, significantly affecting the stability during construction. A bridge closure sequence of side-span, secondary midspan, and midspan provides the most stable condition during the construction phase. The results of this study can inform the construction of similar partially cable-stayed bridges.

Assessment of twelve echovirus virus-neutralisation assays in Europe: recommendations for harmonisation of non-polio enterovirus sero-surveillance studies

Non-polio enteroviruses (NPEV) cause significant disease worldwide. Population-based sero-surveillance, by measuring antibodies against specific NPEV types, provides additional information on past circulation and the prediction for future upsurges. Virus neutralisation assays (VNA), the current method of choice for measuring NPEV type specific antibodies, are not entirely standardised. Via the European Non-Polio Enterovirus Network, we organised a VNA quality assessment in which twelve laboratories participated. We provided five echovirus (E) types (E1, E18, E30 G2, E30 G6 and E6) and intravenous immunoglobulins (IVIG) as a sample for the NPEV VNA quality assessment. Differences in VNA protocols and neutralising Ab (nAb) titres were found between the participating laboratories with geometric coefficients of variation ranging from 10.3–62.9 %. Mixed-effects regression analysis indicated a small but significant effect of type of cell line used. Harmonisation of cell line passage number, however, did not improve variation between laboratories. Calibration by making use of a reference sample, reduced variation between laboratories but differences in nAb titres remained higher than two log2 dilution steps. In conclusion, sero-surveillance data from different laboratories should be compared with caution and standardised protocols are needed.

Moiré patterns of space-filling curves

It is shown on the examples of Moore and Gosper curves that two spatially shifted or twisted, preasymptotic space-filling curves can produce large-scale superstructures akin to moiré patterns. To study physical phenomena emerging from these patterns, a geometrical coupling coefficient based on the Neumann integral is introduced. It is found that moiré patterns appear most defined at the peaks of those coefficients. A physical interpretation of these coefficients as a measure for inductive coupling between radiofrequency resonators leads to a design principle for strongly overlapping resonators with vanishing mutual inductance, which might be interesting for applications in MRI. These findings are demonstrated in graphical, numerical, and physical experiments. Published by the American Physical Society 2024

Development, Optimization, and Validation of an in vitro Cell-Based Bioassay to Determine the Biological Activity of Teriparatide (PTH1–34)

AbstractThis study aimed to establish an efficient in vitro cell-based assay to measure the activity of teriparatide (PTH1–34). In this study, a rat osteosarcoma cell line (UMR-106) was treated with various concentrations of PTH1–34, and the biological activity of PTH1–34 was determined by quantitatively measuring intracellular cyclic adenosine monophosphate levels using a time-resolved fluoroimmunoassay. A four-parameter fitting analysis was used to calculate the relative potency of the samples. The experimental conditions were optimized. The method's specificity, relative accuracy, precision, and linearity were validated. Our data suggested that this method had good specificity, a relative bias of relative accuracy ranging from −0.8 to 1.4%, a correlation coefficient for the linear regression equation of 0.9953, a geometric coefficient of variation for intermediate precision ranges from 2.0 to 3.5%, and a linear range of 50 to 150%. This method significantly improves the quality control and release inspection efficiency of PTH1–34 and may be further developed and validated as an alternative to the existing United States Pharmacopeia and European Pharmacopoeia inclusion methods. This method also provides a platform for the high-throughput screening of PTH1–34 analogs.

Intracellular islatravir-triphosphate half-life supports extended dosing intervals.

Antiretroviral therapy has substantially reduced morbidity, mortality, and disease transmission in people living with HIV. Islatravir is a nucleoside reverse transcriptase translocation inhibitor that inhibits HIV-1 replication by multiple mechanisms of action, and it is in development for the treatment of HIV-1 infection. In preclinical and clinical studies, islatravir had a long half-life (t½) of 3.0 and 8.7 days (72 and 209 hours, respectively); therefore, islatravir is being investigated as a long-acting oral antiretroviral agent. A study was conducted to definitively elucidate the terminal t½ of islatravir and its active form islatravir-triphosphate (islatravir-TP). A single-site, open-label, non-randomized, single-dose phase 1 study was performed to evaluate the pharmacokinetics and safety of islatravir in plasma and the pharmacokinetics of islatravir-TP in peripheral blood mononuclear cells after administration of a single oral dose of islatravir 30 mg. Eligible participants were healthy adult males without HIV infection between the ages of 18 and 65 years. Fourteen participants were enrolled. The median time to maximum plasma islatravir concentration was 1 hour. Plasma islatravir concentrations decreased in a biphasic manner, with a t½ of 73 hours. The t½ (percentage geometric coefficient of variation) of islatravir-TP in peripheral blood mononuclear cells through 6 weeks (~1008 hours) after dosing was 8.1 days or 195 hours (25.6%). Islatravir was generally well tolerated with no drug-related adverse events observed. Islatravir-TP has a long intracellular t½, supporting further clinical investigation of islatravir administered at an extended dosing interval.

Contrasting nature of aerosols over South Asian cities and its surrounding environment

Cross-country assessment of aerosol loading was made over several South Asian megacities using multiple high-resolution remote-sensing database to assess how aerosols vary within the city and its suburbs. Parameters sensitive to aerosol optical and microphysical properties were processed over city-core and its surrounding, separated by a buffer. Cities across the Indo-Gangetic Plain (IGP; AOD:0.52–0.72) along with Mumbai (0.47) and Bangalore (0.46) denote comparatively high aerosol loading against non-IGP cities. City-core specific AOD was invariably high compared to surrounding, however with varying gradient having robust geographical signature. Exceptions to this general trend were in Kathmandu (ΔAOD: 0.07) and Dhaka (ΔAOD: 0.01) while strong positive AOD gradient was noted in Bangalore (+0.11), Colombo (+0.08) and in Mumbai (+0.07). While all mainland cities exhibited robust intraannual variability, distinction between city-core and its surrounding AOD exhibited varying seasonality. City-specific geometric coefficient of variation indicated insignificant association with mean AOD as opposed to European and American cities. Both pixel-based and city-specific analysis revealed a strong increasing trend in AOD with highest magnitude in Varanasi and Bangalore. Aerosol sub-types based on aerosols’ sensitivity to UV-absorption and particle size denotes higher relative abundance of carbonaceous smoke aerosols within city-core, without having significant distinction for mineral dusts and urban aerosols.

A New Class of Univalent Functions Defined by Differential Operator

In the present work, we submit and study a new class $\mathcal{S}_{\lambda, \alpha, b}^{z, m, t}(\beta, \gamma, \omega, \mu)$ containing analytic univalent functions defined by new differential operator $D_{\lambda, \alpha}^{z, m, t}$ in the open unit disk $E=\{s \in \mathbb{C}:|s|<1\}$. We get some geometric properties, such as, coefficient estimate, growth and distortion theorems, convex set, radii of convexity and starlikeness, weighted mean, arithmetic mean and partial sums for functions belonging to the class $\mathcal{S}_{\lambda, \alpha, b}^{z, m, t}(\beta, \gamma, \omega, \mu)$.

The effect of sparkling water on the systemic pharmacokinetics of paracetamol in older adults

Paracetamol absorption kinetics show considerable variability in older adults, complicating the development of effective dosing regimens in the advanced-age population. In previous research, sparkling water has been shown to influence absorption-related processes. This study aimed to apply these findings to older adults and investigate the impact of sparkling water on absorption-related variability and early exposure. To this end, fourteen volunteers, with a median age of 72.5, were enrolled in a small-scale, randomised, controlled clinical trial with a cross-over design. A single immediate-release 500 mg paracetamol tablet was administered with sparkling or still water. Venous blood samples were collected regularly over 8 hours and analysed using HPLC-UV. Reduced variability of absorption-related parameters and a trend towards higher early exposure were observed in the sparkling water group, as demonstrated by a 1.6-fold increased AUC0-30min, a 2-fold reduced geometric coefficient of variation (GCV) for AUC0-30min, and a reduced median [interquartile range] Tmax of 25.0 [20.0–30.0] min compared to 30.0 [25.0–45.0] min. Based on our findings, sparkling water as a real-life dosing condition might improve paracetamol absorption kinetics and early exposure in the advanced-age population.

Stochastic viability in an island model with partial dispersal: Approximation by a diffusion process in the limit of a large number of islands

In this paper, we investigate a finite population undergoing evolution through an island model with partial dispersal and without mutation, where generations are discrete and non-overlapping. The population is structured into D demes, each containing N individuals of two possible types, A and B, whose viability coefficients, sA and sB, respectively, vary randomly from one generation to the next. We assume that the means, variances and covariance of the viability coefficients are inversely proportional to the number of demes D, while higher-order moments are negligible in comparison to 1/D. We use a discrete-time Markov chain with two timescales to model the evolutionary process, and we demonstrate that as the number of demes D approaches infinity, the accelerated Markov chain converges to a diffusion process for any deme size N≥2. This diffusion process allows us to evaluate the fixation probability of type A following its introduction as a single mutant in a population that was fixed for type B. We explore the impact of increasing the variability in the viability coefficients on this fixation probability. At least when N is large enough, it is shown that increasing this variability for type B or decreasing it for type A leads to an increase in the fixation probability of a single A. The effect of the population-scaled variances, σA2 and σB2, can even cancel the effects of the population-scaled means, μA and μB. We also show that the fixation probability of a single A increases as the deme-scaled migration rate increases. Moreover, this probability is higher for type A than for type B if the population-scaled geometric mean viability coefficient is higher for type A than for type B, which means that μA−σA2/2>μB−σB2/2.

Validation of a Pseudovirus Neutralization Assay for Severe Acute Respiratory Syndrome Coronavirus 2: A High-Throughput Method for the Evaluation of Vaccine Immunogenicity.

The evaluation of coronavirus disease 2019 (COVID-19) vaccine immunogenicity remains essential as the severe acute respiratory syncytial virus 2 (SARS-CoV-2) pandemic continues to evolve and as additional variants emerge. Neutralizing antibodies are a known correlate of protection for SARS-CoV-2 vaccines. A pseudovirus neutralization (PNT) assay was developed and validated at Novavax Clinical Immunology Laboratories to allow for the detection of neutralizing antibodies in vaccine clinical trial sera. The PNT assay was precise, accurate, linear, and specific in measuring SARS-CoV-2 neutralization titers in human serum for ancestral strain and the Omicron subvariants BA.5 and XBB.1.5, with an overall geometric coefficient of variation of ≤43.4%, a percent relative bias within the expected range of -60% to 150%, and a linearity value of R2 > 0.98 for all three strains. This pseudovirus assay will be useful for the analysis of vaccine clinical trial samples to assess vaccine immunogenicity. Future work will focus on modifying the assay for emerging variants, including XBB.1.16, EG.5.1, BA.2.86, and any other variants that emerge in the ongoing pandemic.

Analysis of Amplification Effect and Optimal Control of the Toggle-Style Negative Stiffness Viscous Damper

This paper proposes a new toggle-style negative stiffness viscous damper (TNVD), and evaluates the performance of the TNVD with the displacement amplification factor (fd) and the energy dissipation factor (fE). Firstly, the composition and characteristics of the TNVD are introduced. Subsequently, the displacement amplification factor is introduced to evaluate the displacement amplification ability of the TNVD, and it is decomposed into a geometric amplification factor and an effective displacement coefficient. Then, based on the geometric amplification factor and effective displacement coefficient, the correlation between the TNVD’s displacement amplification ability and inter-story deformation is studied, and an improved TNVD is proposed. By the comparison of the finite element calculation results, it is found that the improved TNVD can utilize the assumption of small structural deformation. After that, the impacts of plentiful aspects, such as the length of the lower connecting rod, the horizontal inclination angle of the lower connecting rod, the inter-story deformation limit, the cross-sectional area of the connecting rod, the damping coefficient, and the negative stiffness on the fd and fE of the improved TNVD, are expounded. The research results show that when the length of the TNVD’s lower connecting rod remains unchanged, the fd and fE present a trend of increasing first and then decreasing with the increase in the horizontal inclination angle of the lower connecting rod. When the inter-story deformation is fixed, there exists an optimal lower connecting rod’s length that satisfies a specific relationship to achieve the optimal geometric amplification factor of the TNVD. By adjusting the damping parameters of the TNVD, we can obtain a better effective displacement coefficient greater than 0.95 in the proposed target region. Meanwhile, the fd and fE increase with the decrease in the negative stiffness. An optimization strategy for the improved TNVD has been proposed to ensure that the TNVD has the characteristics of operational safety, ideal displacement amplification capability, and energy dissipation capability. Furthermore, a multi-objective control design method with an additional improved TNVD structure is proposed. The vibration reduction effect of the structure with the improved TNVD and the effectiveness of the optimization strategy are verified through examples.

A Comprehensive Dataset of the Aerodynamic and Geometric Coefficients of Airfoils in the Public Domain

This study presents an extensive collection of data on the aerodynamic behavior at a low Reynolds number and geometric coefficients for 2900 airfoils obtained through the class shape transformation (CST) method. By employing a verified OpenFOAM-based CFD simulation framework, lift and drag coefficients were determined at a Reynolds number of 105. Considering the limited availability of data on low Reynolds number airfoils, this dataset is invaluable for a wide range of applications, including unmanned aerial vehicles (UAVs) and wind turbines. Additionally, the study offers a method for automating CFD simulations that could be applied to obtain aerodynamic coefficients at higher Reynolds numbers. The breadth of this dataset also supports the enhancement and creation of machine learning (ML) models, further advancing research into the aerodynamics of airfoils and lifting surfaces.

Recovery stress, bond resistance, and stiffness to slip of crimped SMA fibers with considering geometric variation

Bond resistance is critical for reinforcing fibers in cementitious materials. Recently, crimped shape memory alloy fibers (SMA) have been raised as candidates for providing abundant benefits such as improved strength, enhanced durability, and crack closing. This study aimed to examine the influence of wave-depth and wave-length of crimped SMA fibers on their bond behavior. The crimped fibers in this study were categorized in four groups based on the wave-length. Each group had four types of fibers that considered the ratio of wave-depth to wave-length (DLR). Thus, a total of sixteen types of fibers were prepared with variations in wave-length and wave-depth. The tensile test used bare crimped SMA fibers, while the pullout tests used half dog-bone specimens. After the tests, the finite element model was used to evaluate the interaction parameters that were difficult to measure in the experience test. The results showed that the fibers with the smallest wave-length showed the largest maximum bond resistance in the same dept-to-length ratio (DLR) group, and that values decreased with an increasing wave-length. In addition, the smallest wave-length fibers demonstrated the most effective stiffness. Furthermore, the finite element analysis discovered that the geometric friction coefficients of the crimped SMA fibers were affected significantly by the geometric variation. The longer wave-length fiber revealed the larger estimated frictional coefficient.

Optimized design of a gravitational wave telescope system based on pupil aberration.

The telescope is vital for accurate gravitational wave detection in the TianQin project. It must meet criteria like a geometric tilt-to-length (TTL) coupling noise c o e f f i c i e n t≤0.02√2n m/µr a d and wavefront R M S≤λ/30. Analyzing the pupil aberration's impact on geometric TTL noise, we devised an optimization method using the chief ray spot diagram's standard deviation. Implementing this in Zemax with a ZPL macro, we designed an optical system meeting TianQin's requirements. The system has a maximum geometric TTL noise coefficient of 0.0250nm/µrad over the science FOV and a wavefront RMS of 0.0111λ, confirming the method's feasibility.

A new approach to predicting the region of facilitated glass formation in the Sc-Y-Co-Al system

The experimental search for concentration ranges of vitrification in three-component systems requires the study of several thousands of compositions, whereas for four or more alloy's components the task becomes impracticable at all. To reduce material costs, it is vital to develop reliable theoretical methods for predicting glass formation regions in multicomponent metal systems. We have developed a new model for predicting the compositions of quaternary amorphous metallic glasses and applied it to the Sc-Y-Co-Al system. The proposed model parameters Θx−yx,Θx−yy make it possible to predict the location of glass-forming compositions by finding the minimum of the PHSS parameter multiplication by the geometric coefficient Γ1,2(x), Γ1,2y. The alloy with the composition Sc33Y32Co19Al16 was successfully predicted and then cast in the form of a glass rod with a lateral size of 3 mm. According to the results of X-ray diffraction and thermal analysis, the sample Sc33Y32Co19Al16 is an amorphous material with the lowest value of the crystallinity index 4%. The proposed approach can be used as a predictive model for determining glass-forming compositions in various quaternary metal systems.

Data-driven semianalytical method for predicting equivalent thickness of flexible pipeline carcass

The carcass layer inside a flexible marine pipeline is a large-angle spiral structure with a complex cross-section. A carcass resists radial loads and prevents flexible pipelines from collapsing under extreme hydrostatic pressures. The accurate evaluation of the critical collapse pressure of a carcass under external pressure is crucial for the safe design of flexible pipelines. Because of the complex cross-section of the carcass, the internal surface of the carcass slides and contacts adjacent layers under external loads, which complicates the analysis. Therefore, the complex cross-section of the carcass is often simplified into a uniform section with a fixed thickness during analysis. In this study, parametric models of the carcass with different cross-sectional parameters were established, and the radial stiffness of the carcass under symmetric radial compression was calculated numerically. Next, the calculated equivalent radial stiffness was introduced into the analytical model to obtain geometric coefficients with different cross-sectional parameters. Finally, symbolic regression was used to derive a mathematical equation relating the equivalent thickness and critical cross-sectional parameters of the carcass. The results showed that the Minimum error in the buckling eigenvalue between the equivalent models and full carcass layer model was 6.2 %, the error in the critical collapse pressure was 14.5 %. Meanwhile, the influence of different parameters on the critical collapse pressure of the carcass was discussed.

Hybrid ANN-GA optimization method for minimizing the coupling in MIMO antennas

In this paper, we propose a novel approach to address the challenge posed by large datasets in the context of antenna optimization through machine learning (ML). The approach involves a modified artificial neural network (ANN) technique. To tackle the issue of training with limited data, we introduce a method that leverages prior knowledge to create initial small datasets. Throughout the training process, these datasets are iteratively enhanced by incorporating new simulation data obtained from optimization results. In the applications presented here, ANN is used to establish a relationship model between antenna geometric variables and transmission coefficients (S21). Subsequently, a genetic algorithm (GA) is used to optimize the decoupling of the antenna array. By implementing wideband and narrowband optimization of the S21 between two antennas, the accuracy and efficiency of this method are verified. The initial design and optimized antennas were fabricated and measured. In summary, this proposed method not only can effectively mitigate the expenses associated with design but also generates antenna optimization solutions of high quality.

Research on the integration management innovation path of tea culture and rural tourism industry under the background of information technology

Abstract This paper analyzes the development of the integration of tea culture and the rural tourism industry by using the coupling coordination model with the goal of promoting rural economic development. The entropy value method is used to calculate the evaluation index of the development level between tea culture and rural tourism industries. Combined with the geometric coefficient of deviation method to calculate the coupling coordination between tea culture and the rural tourism industry. The development index of tea culture and rural tourism industry is built using the index construction principle. By exploring the positive indicators of both tea culture and the rural tourism industry, the problems in the integration of tea culture and the rural tourism industry are analyzed, and the corresponding solution paths are proposed. The results show that the comprehensive development level of tea culture has been on a growing trend from 2018 to 2022.2021 the coupled coordination type of tea culture and rural tourism has reached the state of synchronous development, with a coupled coordination degree of 0.715, which is in the intermediate level of coordination. The development of the rural tourism industry has risen from 0.516 to 0.784. This study improves a new perspective on the integration of tea culture and the rural tourism industry and promotes the integration of the two.

Dynamics of Phytoplankton Species Structure in the Kurile Lake (Kamchatka Peninsula)

The species structure of the dominant community of unicellular algae inhabiting the spawning and feeding salmon lake was studied in the Kurile Lake (southern Kamchatka peninsula). It has been shown that this structure is well described by the Motomura model. The geometric progression coefficient does not differ significantly from the value prescribed by the model, which is based on the stochastic remainder hypothesis. Several integral indicators characterizing the species structure have been calculated. The study has revealed some typical and unusual correlations between these integral indices. Inter-annual and intra-annual cyclical fluctuations in the value of indicators have been found.

SIMULATION OF THE AUTOMATIC CONTROL SYSTEM OF A HORIZONTAL-AXIAL WIND POWER PLANT

We considered the results of modelling the operating modes of an electric power generation system of a horizontal-axial wind turbine. The system consist of an aerodynamic blades of a wind wheel connected by an elastic shaft to a generator through a multiplier. Engineering part of the automatic control system (ACS) is the mechanism of rotation of the blades relative to the angle of wind flow. A method for optimizing the main parameters: geometric, dynamic and ACS coefficients is proposed. The method allows a comprehensive assessment of the operation of wind turbines. The value of the average annual electricity generation was used as an optimization criterion. As a result, a deep optimization of the adjustment depth coefficient was carried out. Secondly, we investigated the system in dynamics. A stochastic wind model was used as a disturbing effect. We constructed the system by mathematic simulation methods. As a reference control algorithm, a direct linear dependence of the angular velocity of the turbine rotation on the wind speed with restrictions on the minimum and maximum values was used. Also we described the mathematical model of system and the initial results of the theoretical calculations of algorithms for controlling. The versatility of the calculation system makes it possible to use any aerodynamic profiles of the blades in its composition. The characteristics of aerodynamic moments for the calculation of force moments are obtained by converting Lilienthal curves as initial data for the considered aerodynamic profiles.