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A new type of shuttle-shaped double-restrained buckling-restrained brace (SDR-BRB) is proposed, which adopts the form of a shuttle-shaped deformation section similar to its bending moment distribution as the external restraining system. The SDR-BRB has the advantages of superlong size, high load-carrying capacity, and lightweight components, and is suitable for use in large-span spatial structures and bridge structures with an exposed BRB. First, the calculation formula of the elastic buckling load of a pin-ended SDR-BRB is derived based on the equilibrium method, which is verified through the eigenvalue buckling analysis method, and the effects of the main geometric parameters on its elastic buckling behavior are evaluated. The effects of multiple key factors on the load-carrying capacity of the SDR-BRB are then studied by parametric analysis. The results show that the restraining ratio, initial imperfection, and gap have significant effects on the ultimate load-carrying capacity and overall stability of the SDR-BRB, while the effect of the diameter–thickness ratio is relatively small. On this basis, the fitting formula of the critical restraining ratio of the SDR-BRB considering the influences of initial imperfection and gap is proposed and verified by finite element analysis. The research lays a foundation for further research into the elastic–plastic hysteretic behavior and design method of an SDR-BRB. [ABSTRACT FROM AUTHOR]

A new type of shuttle-shaped double-restrained buckling-restrained brace (SDR-BRB) is proposed, which adopts the form of a shuttle-shaped deformation section similar to its bending moment distribution as the external restraining system. The SDR-BRB has the advantages of superlong size, high load-carrying capacity, and lightweight components, and is suitable for use in large-span spatial structures and bridge structures with an exposed BRB. First, the calculation formula of the elastic buckling load of a pin-ended SDR-BRB is derived based on the equilibrium method, which is verified through the eigenvalue buckling analysis method, and the effects of the main geometric parameters on its elastic buckling behavior are evaluated. The effects of multiple key factors on the load-carrying capacity of the SDR-BRB are then studied by parametric analysis. The results show that the restraining ratio, initial imperfection, and gap have significant effects on the ultimate load-carrying capacity and overall stability of the SDR-BRB, while the effect of the diameter–thickness ratio is relatively small. On this basis, the fitting formula of the critical restraining ratio of the SDR-BRB considering the influences of initial imperfection and gap is proposed and verified by finite element analysis. The research lays a foundation for further research into the elastic–plastic hysteretic behavior and design method of an SDR-BRB.

The solubility of magnesium sulfate in sulphuric add solution was determined by equilibrium method in the temperature from T = (263.15 to 298. 15 ) K. The results show that the solubility of magnesium sulfate decrease with the decrease of temperature or the increases of sulfuric add concentration. The solubility data was correlated by Apelblat equation, empirical equation. (CNIBS)/ Redlich-Kister equation, and(CNIBS)/Redlich-Kister equation has the best correlation effect, the average relative deviation is 0.41%. The changes of entropy, enthalpy and Gibbs free energy of the dissolving process were obtained by modified Van t-Hoof equation. The results show that the dissolving process of magnesium sulfate was a spontaneous process of endothermic and entropy rincreacing and enthalpy change was the main factor affecting the dissolution process. The experimental results can provide data support for the research of magnesium sulfate removal technology by low temperature crystallization from the waste electrolyte of zinc hydrometallurgy. [ABSTRACT FROM AUTHOR]

The gap acceptance research is an essential research in the estimation of the values of capacity and delay at priority junction. This study was conducted to estimate and compare the value of critical gap using the equilibrium method, maximum likelihood method and Malaysia Highway Capacity Manual (MHCM), conditioned with and without presence of the motorcycles. The two priority junctions with multilane road were targeted and data were recorded using video camera technique. The equilibrium method estimated the critical gap at priority junction with motorcycles approximately 0.17 s shorter than that of priority junction without motorcycles. Similarly, this study has been carried out for maximum likelihood method, and the magnitudes of critical gap with motorcycles were estimated about 0.20 s less than the situation without motorcycles. In the case of MHCM, the results showed a differentiation around 0.04 s between both situations. These close results show that differences of critical gap between both scenarios are very small. However, considering the importance of critical gap for evaluating the operational conditions at priority junctions, we highly recommend the estimation of that gap in some Asian countries such as Malaysia with many motorcycles. [ABSTRACT FROM AUTHOR]

The reconfigurable equilibrium circuit can take account of the number of components and the conversion efficiency and can easily balance every single cell in the battery pack, but the voltage of the battery pack will fluctuate when the battery pack is balanced. To solve this problem, a reconfigurable equalization circuit with an additional power supply is proposed. By replacing the cell with the additional power supply, the purpose of stabilizing the voltage of the battery pack is achieved. Aiming at the additional power supply, this paper puts forward a method that the additional power supply participates in the charging (discharging) process when the SOC (state of charge) of the battery pack is not lower (higher) than the additional power supply while the battery pack is charging (discharging), to make the charge and discharge capacity of the additional power supply always better than the battery pack. The experimental results show that the proposed equalization circuit can not only retain the advantages of the traditional reconfigurable equilibrium circuit but also maintain the voltage of the battery pack in the equalization process. [ABSTRACT FROM AUTHOR]

The concept of influence surface has been largely used for the determination of the internal forces of bridge decks. Differently from the load that acts on usual building structures in bridge decks, those loads are in movement; therefore, a more careful evaluation must be conducted for the determination of the maximum efforts. Equilibrium, Müller-Breslau and Adjoint methods are alternative methodologies for the construction of influence surfaces. This manuscript addresses the implementation of such methods through the finite element method and the application of influence surfaces for the obtaining of internal forces. Parameters, as mesh density and shape functions of finite elements are explored through a numerical example. The results show the three procedures provided similar influence coefficients for shear and bending moments, in nodes distant from the reference point and very sensitive values to the mesh density and shape functions of finite elements in the reference point. The convergence values found for the internal forces calculated with the distributed load of the wheel did not show a strong dependency on the parameters under analysis. [ABSTRACT FROM AUTHOR]

This paper investigates the elastic buckling behaviour and load resistance of a double cross-arm pre-tensioned cable stayed buckling-restrained brace (DPCS-BRB) where an extra cross-arm is assigned within a longitudinal cable truss along its length. Naturally, the span and efficiency of the PCS-BRB can be increased and improved by adopting multiple cross-arms. Equilibrium method is utilised to derive the formula of elastic buckling load of a pin-ended DPCS-BRB, and the obtained results have been verified through FE analysis. It is found from theoretical derivations and FE analysis that there exists a single-wave symmetric and double-wave antisymmetric buckling modes in the DPCS-BRB, respectively. In addition, a negative linear correlation exists between the elastic buckling load and the initial pre-tensioning force of the cables in the DPCS-BRB. Furthermore, it has been explored through FE analysis that the optimal location of the cross-arms for achieving higher elastic buckling load as well as higher ultimate compressive load-carrying capacity is found to be a quarter length to each end of the DPCS-BRB. At last, the ultimate compressive load-carrying capacity of the DPCS-BRB is found to be directly proportional to its restraining ratio, and there exists a lower limit of the restraining ratio which ensures the core could reach its full cross-sectional yield load without overall instability of the DPCS-BRB. The investigation of the elastic buckling behaviour and ultimate compressive load-carrying capacity as well as the failure mechanism of the DPCS-BRB provides fundamentals to the further development of a comprehensive design method of the DPCS-BRB subjected to axial cyclic loads. [ABSTRACT FROM AUTHOR]

In this work, the ratio contribution of Ra and U in γ spectra with the latest update nuclear data will be revised. The results showed that in the total count rate of the 186 keV peak consists of 57.2% of Ra (186.2 keV) and 42.8% of U (185.7 keV) with the existence of equilibrium. These calculations were used for determining mass activity of U for the direct and fast measurement using only the 186 keV peak and verifying the U-Ra secular equilibrium. An equilibrium method was measured secular equilibrium of decay chain U (by the product daughter Bi-609.3 keV) that was used for this study. The maximum relative deviation was less than 4.0% between both methods proved the direct method was reliable and can be applied to determine the mass activity of U in the radioactive equilibrium samples. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of buckling-restrained braces (BRBs), namely shuttle-shaped buckling-restrained braces (SS-BRBs). The proposed SS-BRB is composed of a circular steel tube as the inner core, and a shuttle-shaped thin-walled steel tube as the external restraining member. The space between them is filled by a steel-plate isolation system. The shuttle-shaped restraining member of the SS-BRB significantly improves load-carrying efficiency and saves material in its strength design. Moreover, the SS-BRB is more aesthetically appealing and can be utilized as an exposed BRB in long-span or spatial structures. In terms of the concept of restraining ratio of a BRB, no design method of an SS-BRB is available currently because it concerns the solution of the elastic buckling load of an SS-BRB. Therefore, the elastic buckling load of a pin-ended SS-BRB is initially studied by adopting the equilibrium method and is further verified through finite element (FE) method. The lateral displacement function of an SS-BRB, and the longitudinal stress at the extreme fiber of the external restraining member are derived by considering an initial geometric imperfection that is consistent with the first order overall buckling shape of the SS-BRB. A correction factor considering shear deformation has been incorporated for a more accurate prediction. The lower limit of the restraining ratio for a load-bearing type of SS-BRBs is further obtained based on yielding of the extreme fiber of the restraining member. Furthermore, the proposed formula has incorporated a strain hardening factor for the SS-BRB that experiences strain hardening of the core after its initial yielding. The proposed formulas have been validated through FE numerical analysis. The findings in this paper provide fundamentals to develop the design method for an energy-dissipation type of SS-BRBs. [ABSTRACT FROM AUTHOR]

The solubility data of l -Theanine in pure water and three kinds of water + organic solvent mxitures were measured in temperature ranges from (278.15 to 13.15) K by using an equilibrium method. The results show that the solubility of l -Theanine increases with the increasing of temperature in all selected solvents. The modified Apelblat equation and the λ-h model were applied to correlate the solubility data in pure water, while the modified Apelblat equation, the λ-h model, the NRTL model and the Jouyban–Acree model were applied to correlate the solubility data in binary solvent mixtures. Furthermore, the mixing thermodynamic properties of l -Theanine in different solvents were also calculated based on the NRTL model and experimental solubility data. [ABSTRACT FROM AUTHOR]

A new computational approach is proposed for determining the elastic field of deep curved beams/rings, which is based on a displacement-function equilibrium method. The displacement function is defined in terms of the radial and circumferential components of displacements, which is governed by a single partial differential equation of equilibrium. Solution of the elastic field is obtained in terms of the displacement function, in which both the uniform and the mixed mode of boundary conditions are treated with equal sophistication. The application of the single function computational method is demonstrated through the numerical solutions of a number of problems of curved beams and rings with mixed boundary conditions. The soundness and accuracy of the investigation are verified through the comparison of results with those obtained by conventional computational and analytical approaches available. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of buckling-restrained braces (BRB), namely a pre-tensioned cable stayed buckling-restrained brace (PCS-BRB) which is formed through introducing an additional structural system of pre-tensioned cables and a number of cross-arms to the outside of a common BRB. This new system significantly improves the BRB’s overall external restraining stiffness, hence increasing the load-carrying efficiency in its structural design. Due to its aesthetically appealing structure, it can be utilised in stadiums and so forth as a laterally resistant brace. Equilibrium method is utilised to deduce formulas of elastic buckling load of pin-ended PCS-BRB. The restraining ratio and the initial pre-tensioning force of cables are investigated to explore the effect on the axial compressive load-carrying capacity of the PCS-BRB through finite element analyses in elastic-plastic range. The findings indicate that two different types of buckling modes may occur in this PCS-BRB, namely single-wave symmetric and double-wave antisymmetric buckling modes. It was found from theoretical and numerical analyses that: a negative linear correlation exists between elastic buckling load and initial pre-tensioning force of the cables; the geometric parameters of the cable stayed system possessed remarkable effect on the elastic buckling load. In addition, the post-yield behaviour and ultimate compressive load-carrying capacity of the PCS-BRB is directly proportional to the restraining ratio, and there exists a lower limit of the restraining ratio which allows the inner core to reach full cross-sectional yielding without overall instability failure of the PCS-BRB. Furthermore, there exists an optimal initial pre-tensioning force of cables to make the load-carrying capacity of the PCS-BRB to reach a maximum value. The investigation of elastic buckling and load resistance of PCS-BRB provides fundamentals to further develop a complete design method of PCS-BRB. [ABSTRACT FROM AUTHOR]

In natural gas treatment, the removal of CO2 and H2S in acid gases is a critical concern. There are various purification technologies that can be used for the removal of acid gas impurities. Absorption of acid gas into amines is one preferred method in gas industries. In the past, single amines was used, but recently in order to improve absorption performance, mixed amines with different solubility and reaction rates have been used. In this study, artificial neural network ANN is used as a method to model the absorption tower when uses mixed amines. A specified model which is simple in calculation and good in accuracy was developed. In this model back propagation learning is used and the corresponding parameters have been optimized. Finally, the new method has been compared with conventional mass transfer and equilibrium methods. The obtained results confirmed the simplicity and accuracy of the developed method.

• Energy-based investigation of settlements induced internal stresses in masonry structures. • Continuous Airy-based Stress-Singularities (CASS) method is introduced and investigated. • CASS is benchmarked against analytical and numerical solutions. • CASS describes singular internal stress states as concentrated on narrow bands. • CASS is mesh independent and captures stress singularities crossing the elements. Unreinforced masonry buildings represent a large part of the world's architectural heritage. Despite their significant diffusion, their mechanical behaviour is still subjected to increasing scientific investigations as modelling difficulties arise from the negligible tensile strength in tension. Because of this unilateral response, masonry constructions can flexibly accommodate different loading and displacement-like boundary conditions in a new deformed configuration through the formation of crack patterns. The internal stress state changes accordingly and can be represented through stress singularities. Defining the internal stress states compatible with general boundary conditions is primarily essential from an engineering perspective. This paper presents the Continuous Airy-based for Stress-Singularities (CASS) method, a new numerical strategy to model the internal stress state in unilateral materials, whose main peculiarity is the ability in describing singular stress fields independently of the discretisation. The internal equilibrium is guaranteed using the Airy stress potential discretising the domain with plate-type finite elements. The compatibility with boundary displacements is satisfied through a variational formulation based on the minimum of the Total Complementary Energy. The boundary value problem is then reduced to a second-order cone programming where the linear objective function represents the work of the emerging stress for the boundary displacements, and the constraints enforce the boundary equilibrium and the material compatibility. The CASS method is benchmarked against analytical solutions and other numerical strategies on several 2D problems, also used to illustrate and discuss its main features. Lastly, a real masonry façade is considered to show the method's effectiveness clearly. [ABSTRACT FROM AUTHOR]

The optimization design of the open pit slope can ensure safety in production at the same time bring considerable economic benefits, so it is necessary to evaluate the stability of the initial excavation scheme of the high slope in an open-pit mine and optimize the initial slope angle according to the evaluation results. In this paper, an exhaustive study of Anyi open-pit mine in mouding County Yunnan province China has been made, and the following results have been achieved: (1)Confirmed the geological factors which affected the slope stability of open-pit mine; (2)Quantified the stability of the open-pit mine slope; (3) Under the premise of safety, the angle of the open pit high slope has been optimized on the base of the calculations of the open-pit mine high slope stability so as to ensure the maximum economic benefit. In this paper, the study area was divided into six zones. Firstly, qualitative analysis of slope stability was made by analogy method of engineering geology and stereographic projection method according to the orebody location, the properties of rock and soil in slope, the height of slope, and so on. The analysis shows that the preliminary design of slope angle is so large to ensure safety. Secondly, the stability of different slopes of a high slope is the quantitative analysis of different zones in high slope was made by two-dimensional limit equilibrium method and the finite difference method. In this paper, the mechanical parameters of rock are obtained by a laboratory test, and the stability of the high slope is quantitatively analyzed by two-dimensional limit equilibrium and three-dimensional numerical simulation. • Confirmed the geological factors which affected the slope stability. • Quantified the stability of the open-pit mine slope. • Under the premise of safety, the angle of the open pit high slope. • The preliminary design of slope angle is so large to ensure safety. [ABSTRACT FROM AUTHOR]

Inverted T-shaped precast ribbed panels are used as single-span simply supported bottom plates in concrete composite slabs. The panels have regularly distributed holes in the ribs; therefore they are not only convenient for pipeline layout, but also work well with cast-in-situ concrete layer. An experiment of precast ribbed panels was carried out under out-plane vertical static loading; it was found that the panels were damaged due to concrete shear failure between rib holes near supports. This is different from mid-span bending failure observed in similar experiment by other scholars. The main reason is related to size effect of concrete shear plane. Then, finite element simulation was performed by using commercial software ABAQUS to model the failure mode and bearing capacity of the panel under out-plane vertical static loading, the numerical results are in good agreement with the experimental results. Furthermore, an equilibrium method was proposed to estimate the ultimate bearing capacity for mid-span bending failure and concrete shear failure, respectively. Finally, parametric analysis with the equilibrium method was done to investigate influences of concrete strength and cross sectional dimension on the mechanical behavior of the precast ribbed panels. Compared with the test data and the finite element results, it is concluded that the proposed equilibrium method can predict the failure mode and ultimate bearing capacity of precast ribbed panels. [ABSTRACT FROM AUTHOR]

Abstract: We propose a method, Temperature Integration, which allows an efficient calculation of free energy differences between two systems of interest, with the same degrees of freedom, which may have rough energy landscapes. The method is based on calculating, for each single system, the difference between the values of at two temperatures, using a Parallel Tempering procedure. If our two systems of interest have the same phase space volume, they have the same values of at high- , and we can obtain the free energy difference between them, using the two single-system calculations described above. If the phase space volume of a system is known, our method can be used to calculate its absolute (versus relative) free energy as well. We apply our method and demonstrate its efficiency on a “toy model” of hard rods on a 1-dimensional ring. [Copyright &y& Elsevier]

Highlights: [•] An equilibrium method is developed for computing critical equilibrium states. [•] Non-linearly elastic linkages are studied considering large displacements. [•] Statically indeterminate structures and general loadings are dealt with. [•] A global, robust numerical procedure is utilised. [•] Snapping phenomena and structurally unstable equilibrium states are revealed. [ABSTRACT FROM AUTHOR]

Abstract: A new PET ligand, 3-fluoro-5-(2-(2-18F-(fluoromethyl)-thiazol-4-yl)ethynyl)benzonitrile (18F-SP203) can quantify metabotropic glutamate subtype 5 receptors (mGluR5) in human brain by a bolus injection and kinetic modeling. As an alternative approach to a bolus injection, binding can simply be measured as a ratio of tissue to metabolite-corrected plasma at a single time point under equilibrium conditions achieved by administering the radioligand with a bolus injection followed by a constant infusion. The purpose of this study was to validate the equilibrium method as an alternative to the standard kinetic method for measuring 18F-SP203 binding in the brain. Nine healthy subjects were injected with 18F-SP203 using a bolus plus constant infusion for 300min. A single ratio of bolus-to-constant infusion (the activity of bolus equaled to that of infusion over 219min) was applied to all subjects to achieve equilibrium in approximately 120min. As a measure of ligand binding, we compared total distribution volume (V T) calculated by the equilibrium and kinetic methods in each scan. The equilibrium method calculated V T by the ratio of radioactivity in the brain to the concentration of 18F-SP203 in arterial plasma at 120min, and the kinetic method calculated V T by a two-tissue compartment model using brain and plasma dynamic data from 0 to 120min. V T obtained via the equilibrium method was highly correlated with V T obtained via kinetic modeling. Inter-subject variability of V T obtained via the equilibrium method was slightly smaller than V T obtained via the kinetic method. V T obtained via the equilibrium method was ~10% higher than V T obtained via the kinetic method, indicating a small difference between the measurements. Taken together, the results of this study show that using the equilibrium method is an acceptable alternative to the standard kinetic method when using 18F-SP203 to measure mGluR5. Although small differences in the measurements obtained via the equilibrium and kinetic methods exist, both methods consistently measured mGluR5 as indicated by the highly correlated V T values; the equilibrium method was slightly more precise, as indirectly measured by the smaller coefficient of variability across subjects. In addition, when using 18F-SP203, the equilibrium method is more efficient because it requires much less data. [Copyright &y& Elsevier]

Abstract: A model based on the limit equilibrium method is developed for the analysis of shallow instabilities in soil slopes reinforced with nailed steel wire meshes. Shallow instabilities are associated to ground weathering or shallow water flow affecting a moderate depth, about 10–20% of the slope height. These effects are considered in the analysis as a reduction of the soil strength. The reinforcing mesh is assumed to act as a distributed pressure on the slope surface. The aim is to determine the value of the normal pressure needed to reach a given safety factor against shallow instability. The proposed method is presented first for an infinite slope, leading to a closed form solution. If the height of the slope has to be considered as finite, a second analysis is developed dividing the unstable layer of soil in finite blocks. The result is given as a correction factor to be applied to the infinite slope solution. An application example is used to illustrate the design of practical cases. The results of the limit analysis are compared with finite element calculations. The stabilization effect achieved by the wire mesh is evaluated as the increase of the possible reduction of the soil strength before the slope failure. [Copyright &y& Elsevier]

Abstract: Gas phase basicity of three homologuous bidentate bases: 1,3-propanediamine, 1, 1,3-propanolamine, 2, and 1,3-propanediol, 3, has been determined by Fourier transform ion cyclotron resonance mass spectrometry. Both, the equilibrium and the thermokinetic methods were used and the results were compared with previous experimental and theoretical determinations. An excellent agreement is generally found between the gas phase basicities given by all the methods if corrections due to entropy variations are taken into account. In particular it is shown that a correction given by the term , where T is an “effective temperature” and Δp S° the protonation entropy of the considered species, should be applied to the thermokinetic determination. [Copyright &y& Elsevier]

Insulin's action to stimulate glucose utilization is determined by the insulin concentration in interstitial fluid (ISF) of insulin-sensitive tissues. The concentration of interstitial insulin has been measured in human subcutaneous adipose tissue and skeletal muscle, however, never in parallel. The aim of this study was to compare interstitial insulin levels between both tissue beds by simultaneous measurements and to verify and quantify low peripheral ISF insulin fractions as found during moderato hyperinsulinemia. Nine healthy subjects (27.2 ± 0.8 yr) were investigated. A euglycemic-hyperinsulinemic clamp was started with a primed-constant intravenous insulin infusion of 1 mU·kg-1,min-1. For direct access to ISF, macroscopically perforated open-flow microperfusion catheters were inserted in both tissues. During steady-state conditions (9.5 h), interstitial effluents were collected in 30-min fractions using five different insulin concentrations in the inflowing perfusates (‘no net flux’ protocol). Regression analysis of insulin concentrations in perfusates and effluents yielded the relative recovery and the perfusate insulin concentration, which was in equilibrium with the surrounding tissue. Thus, in subcutaneous adipose tissue and skeletal muscle, the mean ISF-to-serum insulin level was calculated as 21.0% [95% confidence interval (CI) 17.5–24.5] and 26.0% (95% CI 19.1–32.8; P = 0.14), respectively. Recoveries for insulin averaged 51 and 64%, respectively. The data suggest that the concentrations of insulin arising in healthy subjects at the level of ISF per se are comparable between subcutaneous adipose and skeletal muscle tissue. The low interstitial insulin fractions seem to confirm reports of low peripheral insulin levels during moderate insulin clamps. [ABSTRACT FROM AUTHOR]

Given a P1 conforming or nonconforming Galerkin finite element method (GFEM) solution ph, which approximates the exact solution p of the diffusion-reaction equation - ∇·Κ ∇+ αp = f with full tensor variable coefficient Κ, we evaluate the approximate flux uh to the exact flux u = -Κ ∇p by a simple but physically intuitive formula over each finite element. The flux is sought in the continuous (in normal component) or the discontinuous Raviart­Thomas space. A systematic way of deriving such a formula is introduced. This direct method retains local conservation property at the element level, typical of mixed methods (finite element or finite volume type), but avoids solving an indefinite linear system. In short, the present method retains the best of the GFEM and the mixed method but without their shortcomings. Thus we view our method as a conservative GFEM and demonstrate its equivalence to a certain mixed finite volume box method. The equivalence theorems explain how the pressure can decouple basically cost free from the mixed formulation. The accuracy in the flux is of first order in the H(div;Ω) norm. Numerical results are provided to support the theory. [ABSTRACT FROM AUTHOR]