Modelling competition between the siderophore ferrioxamine B and humic like binding sites in seawater v1

Here we archive a protocol that can be used to determine competition between a siderophore (ferrioxamine B) and humic like binding sites that are present in marine DOM. We use the NICA-Donnan model to describe binding by humic like binding sites in DOM. Constants for Fe binding to marine DOM are taken from Zhu et al., (2021). Thermodynamic constants describing binding between major ions, iron and ferrioxamine B are taken from Schijf and Burns, (2016). References Schijf, J., Burns, S.M., 2016. Determination of the Side-Reaction Coefficient of Desferrioxamine B in Trace-Metal-Free Seawater. Front. Mar. Sci. 3, 117. https://doi.org/10.3389/fmars.2016.00117 Zhu, K., Birchill, A.J., Milne, A., Ussher, S.J., Humphreys, M.P., Carr, N., Mahaffey, C., Lohan, M.C., Achterberg, E.P., Gledhill, M., 2021a. Equilbrium calculations of iron speciation and apparent iron solubility in the Celtic Sea at ambient pH using the NICA-Donnan model. Mar. Chem

Numerical Simulation of the Photobleaching Process in Laser-Induced Fluorescence Photobleaching Anemometer

At present, a novel flow diagnostic technique for micro/nanofluidics velocity measurement—laser-induced fluorescence photobleaching anemometer (LIFPA)—has been developed and successfully applied in broad areas, e.g., electrokinetic turbulence in micromixers and AC electroosmotic flow. Nevertheless, in previous investigations, to qualitatively reveal the dynamics of the photobleaching process of LIFPA, an approximation of uniform laser distribution was applied. This is different from the actual condition where the laser power density distribution is normally Gaussian. In this investigation, we numerically studied the photobleaching process of fluorescent dye in the laser focus region, according to the convection–diffusion reaction equation. The profiles of effective dye concentration and fluorescence were elucidated. The relationship between the commonly used photobleaching time constant obtained by experiments and the photochemical reaction coefficient is revealed. With the established model, we further discuss the effective spatial resolution of LIFPA and study the influence of the detection region of fluorescence on the performance of the LIFPA system. It is found that at sufficiently high excitation laser power density, LIFPA can even achieve a super-resolution that breaks the limit of optical diffraction. We hope the current investigation can reveal the photobleaching process of fluorescent dye under high laser power density illumination, to enhance our understanding of fluorescent dynamics and photochemistry and develop more powerful photobleaching-related flow diagnostic techniques.

Estimating an empirical equation connecting subgrade reaction modulus with cone penetration test for sandy soils

In geotechnical engineering, the coefficient of subgrade reaction is regarded as one of the most important parameters used for describing the interaction of soil and structure as well as describing some soil characteristics, subgrade reaction coefficient can be calculated theoretically using many different formulas, laboratory via specific well-known tests, and in site through field plate loading test. On the other hand, the cone penetration test is one of the most frequently used field tests to investigate the soil. The lately carried out researches showed a good relation between the subgrade coefficient and the tip resistance collected from the CPT, but the results obtained from the proposed method are still doubtable. In this paper, fifteen plate load tests and thirty CPTs, already collected for private site investigation project, have been used for finding the best fit equation connecting the subgrade reaction coefficient Ks with the tip resistance qc. The finds of the established equation have been compared extensively with those of other well-known related equations. The results show the ability of the concluded equation to get Ks results in the acceptable range of sandy soils. However, the depth and shape effect on the suggested formula need further investigations since all the plate load tests in this project have been carried out on the soil surface with a 45 cm diameter circular plate.

Vertical Channel Conflict Coordination Strategy of e-Commerce Supply Chain under Platform Brand Empowerment

We develop a game model for a supply chain consisting of one e-commerce platform, one supplier from other channels, and one retailer. The platform has a well-known brand that can influence consumers’ purchase decisions, and it provides good-quality products with high prices, while supplier from other channels provides cheaper products but possibly with low quality, and there may even be some serious quality problems, sometimes leading to serious problems such as “free-riding” behavior by the retailer and reducing the profits of the supply chain members. First, we study the decisions of platform and retailer under centralized decision (CD) scenario, decentralized decision (DD) scenario, cost sharing contract (CS) scenario, and minimum order quantity contract (QC) scenario. Second, we found that channel conflicts have a negative impact on supply chain members under DD scenario; however, CS and QC scenarios can make the optimal empowerment level of platform the same as CD scenario and encourage retailer to order more products from platform. Finally, the improvement effect in QC and CS scenarios is affected by the substitutability of the two products, the coefficient of empowerment cost, and the reaction coefficient of product price on goodwill. Furthermore, we found that under QC scenario, only within an appropriate range can the platform and the retailer achieve a win-win situation.

Parameter-Dependent Feedback Compensator Design for a Time-Fractional Reaction-Diffusion Equation

This paper presents a parameter-dependent design of feedback compensator with space-varying gains for Mittag-Leffler stabilization of linear time fractional parabolic MIMO partial differential equations subject to space-varying diffusion and reaction coefficients. In the proposed design method, under a boundedness assumption, the reaction coefficient is written in a parametric form. By using the parametric form for the reaction coefficient and multiple non-collocated observation outputs, an observer-based state feedback compensator with space-varying gains is then constructed such that the resulting closed-loop coupled equations are Mittag-Leffler stable. By applying the Lyapunov technique with Caputo fractional derivative and variants of Poincaré–Wirtinger’s inequality, a sufficient condition for the existence of such feedback compensator is presented in terms of standard linear matrix inequalities. Finally, simulation results are presented to support the proposed design method.

A Simplified Analysis Method for the Deformation Response of an Existing Tunnel to Ground Surcharge Based on the Pasternak Model

Surface surcharge changes the existing equilibrium stress field of the stratum and adversely affects the existing tunnel. This paper presents a simplified analytical solution for calculating the longitudinal displacement of existing tunnels that are subjected to adjacent surcharge loading. Based on the Boussinesq solution, the distribution of the additional load matrix caused by the surface surcharge on the existing tunnel was obtained. A Euler–Bernoulli beam with a Pasternak foundation was used as a simplified model for tunnel stress analysis. Using the corrected reaction coefficient of the foundation bed, the differential equation of tunnel deformation was established, and the solution matrix of the longitudinal displacement of the tunnel was obtained by using the finite difference method. The reliability and applicability of the proposed method were verified by comparing the results with finite element simulation results, field test data, and the calculation results of three simplified elastic analysis methods with different foundation bed coefficients. On this basis, the parameters of the load–tunnel model were analyzed, and the effects of the buried depth, the size of the load, the relative positions of the load and the tunnel, and the relative stiffness of the tunnel soil on the maximum displacement of the existing tunnel were calculated. An empirical formula is proposed for calculating the maximum longitudinal displacement of the existing tunnel subjected to surface surcharge. The findings of this research can provide a basis for the theoretical verification of the deformation response of an existing tunnel subjected to adjacent surface surcharge.

Studi Perbandingan Pengajaran Reaksi Reduksi Oksidasi Antara Cara Perubahan Bilangan Oksidasi dengan Cara Setengah Reaksi terhadap Hasil Belajar Siswa Kelas XII IPA 1 dan XII IPA 2

Oxidation-Reduction Reactions (Redox) are one of the hardest reactions to equalize, this means that it is hard to determine the suitable Reaction Coefficient. An easier and more logical train of thought is to remember that a Reduction and an Oxidation reaction happens simultaneously. A Redox Reaction has two methods in order to equalize, that which is by using the “Change in Oxidation Number” method or the “Half-Reaction (Ion-Electron)” method. The students’ skills in completing a Redox Reaction can be observed in the grades that they have achieved. This observation is intended to find out if there is a difference in students’ grades if you were to teach them about the equalization of Redox Reactions using either of these two methods (the “Change in Oxidation Number” method and the “Half-Reaction” method). The population in this observation consists of the students of Class XII IPA 1 and Class XII IPA 2 of SMAS PERTIWI Jambi that are studying Oxidation-Reduction Reactions. Sample members consist of the students of Class XII IPA 1 and the students of Class XII IPA 3 of SMAS Pertiwi Jambi. The measuring instrument used is a test that has fulfilled standards. Normality tests and Homogeneity tests of the sample in question has been done before the Hypothetical test was implemented. The average grades of students using the “Change in Oxidation Number” method and the “Half-Reaction” method is 11.75 and 10.8 respectively. The T-value of calculations is approximately 1.81 while the T-value of tables is approximately 2.00. With the Level of Significance being 0.05. From the data provided above, it can be concluded that there is no difference in student grades whether the “Change in Oxidation Numbers” method or the “Half-Reaction” method is used to equalize Redox Reactions in applicative aspects.