One-dimensional Analytical Method Research Articles

Monitoring oxidation in recombinant monoclonal antibodies at subunit level through two-dimensional liquid chromatography coupled with mass spectrometry

Monoclonal antibodies (mAbs) are highly susceptible to chemical/post-translational modifications (PTMs), a crucial concern for chemical and biological safety during mAb production and development. Modifications in different mAb domains have different consequences on mAb stability and activity. Hence, characterization and monitoring of domain-specific modification in mAbs is of significant interest so as to be able to assure consistency in product quality. Generally, mAb samples are enzymatically digested and analyzed with traditional reversed-phase chromatography for domain-specific characterization. However, conventional analytical methods do not provide complete resolution and identification of mAb modifications. Here, a novel workflow of two-dimensional liquid chromatography with mass spectrometry interfacing has been proposed to overcome the limitations of conventional one-dimensional analytical methods and provide complete information on oxidized mAb domains. The proposed method successfully analysed the oxidized mAb samples and the control sample at the subunit level, simultaneously separating oxidized variants that are otherwise not detected by one-dimensional methods. The proposed 2D WCX-RPC-MS setup uses 2D multiple heart-cut method that identified 10 oxidation variants in mAb A, 6 in the Fab fragment and 4 in the Fc fragment, of which 3 were exclusive and not identified by the conventional 1D analysis. Further the 2D method takes only 7–13 h in sample preparation and analysis to anticipate oxidation in mAb fragments. Hence, the proposed workflow offers a faster and more convenient platform for routine monitoring and domain-specific mAb characterization with mass spectrometry coupling.

Holistic Variability Analysis in Resistive Switching Memories Using a Two-Dimensional Variability Coefficient.

We present a new methodology to quantify the variability of resistive switching memories. Instead of statistically analyzing few data points extracted from current versus voltage (I-V) plots, such as switching voltages or state resistances, we take into account the whole I-V curve measured in each RS cycle. This means going from a one-dimensional data set to a two-dimensional data set, in which every point of each I-V curve measured is included in the variability calculation. We introduce a new coefficient (named two-dimensional variability coefficient, 2DVC) that reveals additional variability information to which traditional one-dimensional analytical methods (such as the coefficient of variation) are blind. This novel approach provides a holistic variability metric for a better understanding of the functioning of resistive switching memories.

Low frequency sound insulation of membrane-type acoustic metamaterials with negative pressure cavity

The membrane-type acoustic metamaterial with negative pressure cavity (MAM-NPC) is designed to achieve low frequency sound insulation and tunable frequency on the duct side wall. A one-dimensional analytical method was used to discuss the sound insulation effect of MAM-NPC on the sidewall of the duct. As the negative pressure increases, the first valley of sound insulation moves to high frequency. High sound insulation can be achieved in the low frequency range. The theoretical and finite element method results are compared. The one-dimensional analysis method basically agrees with the finite element results in the low frequency band. Because only plane waves are considered in the one-dimensional analytical method.

A Beam Finite Element Model Considering the Slip, Shear Lag, and Time-Dependent Effects of Steel–Concrete Composite Box Beams

A beam finite element model considering the slip, shear lag, and time-dependent effects of steel–concrete composite box beams have been proposed in this study. The element is employed to a one-dimensional analytical method that is solved involving an expression of spatial and time-dependent variables. A step-by-step method that does not involve storing the stress and strain histories, which is more accurate than the single-step algebraic method, is employed to solve the time variables. A recursive method was elaborated to determine spatial and time-dependent variables through the above method. The validity of the proposed method in instantaneous analysis is attested by the numerical data of the elaborate finite element model established in a commercial software, ANSYS, and that of the time-dependent analysis is verified by the existing test results on the long-term performance of composite beams. The proposed beam finite element model is applied to predict the time-related behavior of simply supported composite beams after validation. The results show that concrete shrinkage and creep significantly influence the structural responses of the composite box beams. From the initial load on the 28th day to that in the 3rd year, the vertical deflection at the cross-section of the mid-span increased by 47.01%. The interface slip at the end increased by −10.99%. The warping intensity function of the concrete slab and the steel beam at the end caused by shear lag increased by 111.64% and 7.01%, respectively. The maximum compressive stress on the concrete slab and the maximum tensile stress at the steel bottom flange increased by −6.75% and 4.56%, respectively.

2‐D analytical on‐load electromagnetic model for double‐layer slotted interior permanent magnet synchronous machines

A fast hybrid analytical model is presented to predict the on-load performance of double-layer interior permanent-magnet synchronous machines (IPMSMs) considering both iron bridges saturation and slotting effects. The saturation of the iron bridges is defined by a constant flux in the magnetic equivalent circuit method. The slotting effect is defined by a flux path function and virtual surface currents (VSCs) in one-dimensional (1-D) and two-dimensional (2-D) analytical methods, respectively. For the no-load condition, double-layer IPMSMs are modelled via surface-mounted permanent magnet synchronous machines with two types of the permanent magnet model and the Magnetic Islands method are used to calculate the armature reaction. The effect of the stator slots is considered by using VSCs. To increase the computation speed in the 2-D analytical method, the amount of VSC is calculated by 1-D analysis. The 1-D and 2-D analytical results for a double-layer IPMSM are compared with those of finite element analysis and experimental set-up.

Analytical method for estimating leakage of reservoir basins for pumped storage power stations

Pumped storage power stations are increasingly constructed around cities to provide electric power and ensure grid stability. However, the upper reservoirs are typically located on mountaintops, and the reservoir leakage, which directly affects the economic benefits, is typically difficult to estimate. Therefore, to calculate the leakage within a short period, a one-dimensional simplified analytical method for estimating the leakage of pumped storage power station reservoir basins is proposed based on the stable seepage theory and Darcy’s law. Formulae are derived to calculate the seepage flux of the reservoir basin with different groundwater levels, which can be below or above the bottom of the reservoir basin. The reliability of this analytical method was validated using numerical analysis with regard to a pumped storage power station in China, and the relative errors between the analytical results and the numerical results are less than 5%. The proposed method is beneficial for engineering decision-making and design before the construction of pumped storage power stations.

Reprint of: Surface temperature of a multi-layer thermal barrier coated wall subject to an unsteady heat flux

A one-dimensional analytical method of determining the surface temperature of a thermal barrier coated plane wall subjected to an arbitrarily time-varying heat flux was developed. The method allows fast computation, enabling it to be embedded in combustion simulation software to correctly calculate wall heat transfer, which is important for reciprocating engine applications with thin, low thermal inertia coatings that have large temperature swings. The method relies on superposition of the response to successive step changes in heat flux, obtained by discretizing the heat flux history, to compile the solution. The embedded problem of a step-change in heat flux is addressed using the one-dimensional heat diffusion equation in conjunction with the matrix method in the Laplace domain, assuming the lateral conduction is neglected. For a two-layer wall (one coating layer on top of the metal wall) in the limit where kρc of the coating is small relative to that for the wall material, an analytical inversion to the time domain can be derived. For modest values of this parameter or for more than one coating layer, the residue theorem is invoked to invert to the time domain, with the poles and residues found numerically. The analytical inversion, however, provided the impetus for defining a set of non-dimensional parameters that uniquely characterize the surface temperature swing for arbitrary periodic heat flux to the wall. Non-dimensional results are given for a sinusoidially varying surface heat flux.

Surface temperature of a multi-layer thermal barrier coated wall subject to an unsteady heat flux

A one-dimensional analytical method of determining the surface temperature of a thermal barrier coated plane wall subjected to an arbitrarily time-varying heat flux was developed. The method allows fast computation, enabling it to be embedded in combustion simulation software to correctly calculate wall heat transfer, which is important for reciprocating engine applications with thin, low thermal inertia coatings that have large temperature swings. The method relies on superposition of the response to successive step changes in heat flux, obtained by discretizing the heat flux history, to compile the solution. The embedded problem of a step-change in heat flux is addressed using the one-dimensional heat diffusion equation in conjunction with the matrix method in the Laplace domain, assuming the lateral conduction is neglected. For a two-layer wall (one coating layer on top of the metal wall) in the limit where kρc of the coating is small relative to that for the wall material, an analytical inversion to the time domain can be derived. For modest values of this parameter or for more than one coating layer, the residue theorem is invoked to invert to the time domain, with the poles and residues found numerically. The analytical inversion, however, provided the impetus for defining a set of non-dimensional parameters that uniquely characterize the surface temperature swing for arbitrary periodic heat flux to the wall. Non-dimensional results are given for a sinusoidially varying surface heat flux.

Numerical and Experimental Analysis of the Effect of Acoustic Loads on the Source Characterization for an Internal Combustion Engine Exhaust System

The identification of source characteristics, commonly characterized as the source strength and source impedance, is essential for predicting the acoustic performance of an internal combustion (IC) engine exhaust system. This study contributes to a theoretical analysis of the effect of the acoustic parameters of loads (i.e., four-pole parameters, load impedance, and radiation impedance of the tailpipe) on the identification error of the source characteristics for an IC engine. A model based on the linear time-invariant hypothesis was constructed. A dispersion estimation function of the source strength and a deviation estimation function of the source impedance were established as indicators to test the identification accuracy. A three-dimensional (3D) multifield coupling numerical simulation method, which can thoroughly consider the influences of airflow and temperature, was applied to obtain the acoustic parameters of loads and compare them with those obtained by a one-dimensional (1D) analytical method. Then, the acoustic parameters of loads and the radiated sound pressure level of the tailpipe obtained in the measurement were substituted into the source characteristics identification model. Based on the analysis and calculation, the estimated error of the source characteristics acquired by using the 3D numerical simulation method is significantly lower than that by using the 1D analytical method. Moreover, the experiment and the 3D multifield coupling numerical simulation method were used to verify the identification results of the engine source characteristics. The results show that the far-field sound pressure level of the tailpipe predicted via the 3D numerical simulation method agrees well with the experimental results, indicating that accurate acoustic parameters of loads can effectively improve the source identification accuracy for an IC engine.

Low-Frequency Noise Reduction of Rocket Fairings Using Horn-Shaped-Neck Helmholtz Resonators

The low-frequency noise attenuation technology inside rocket fairings using Helmholtz resonators with horn-shaped neck is constructed. The acoustic performance of a Helmholtz resonator with horn-shaped neck is investigated by methods combining theory, simulation, and experiment. A one-dimensional analytical method is developed to determine the resonance frequency under rigid-wall assumption, whereas an electroacoustic analogy approach is applied to consider the effect of compliant wall, and the theoretical analysis is verified by three-dimensional finite element method. Moreover, the influence of different neck types and wall thickness on the resonance frequency is compared. The main mechanism of sound absorption of a Helmholtz resonator is also studied, and experimental verification on this is carried out in an impedance tube. Results indicate that the resonant frequency can be controlled by neck shape and wall thickness, and the viscous damping at the neck is the main noise-reduction mechanism of this kind of Helmholtz resonator. The finite element model of a rocket fairing is established, and the response characteristic of a fairing cavity is obtained, based on which the certain size horn-shaped-neck Helmholtz resonators are designed and made out. The availability of Horn-shaped-neck Helmholtz resonators on low-frequency noise reduction is demonstrated by test and simulation.

Buckling Analysis of Laminated Composite Plate on Tensionless Elastic Foundations Under Uniaxial Compression

This paper addresses the compressive local buckling behavior of an infinitely long laminated composite plate resting on a tensionless elastic foundation (Winkler foundation). The analytical solution to the contact buckling coefficient of a laminated composite plate is derived using a one-dimensional analytical method. Numerical examples are considered to investigate the influence of the ply angle and foundation stiffness on the contact buckling coefficients of laminated composite plates under uniaxial compression. The lateral boundary conditions including clamped and simply-supported edges are treated. Finally, finite element (FE) analysis is conducted to provide an independent check on the analytical solutions.

Postconstruction Settlement Prediction of High Embankment of Silty Clay at Chengde Airport Based on One-Dimensional Creep Analytical Method: Case Study

Postconstruction Settlement Prediction of High Embankment of Silty Clay at Chengde Airport Based on One-Dimensional Creep Analytical Method: Case Study

Spatial Variability Pattern of Hyporheic Exchange in a braided River

The streambed flux is variable in space; the spatial variability results in part from bedforms, but few works on streambed fluxes in channels with strongly abrupt varying bedforms are carried out. Heat as a tracer to delineate the streambed flux pattern has been widely adopted in numerous fields. In this paper, a braided channel with complicated topography was selected as study site, where the temperature was monitored. One-dimensional (1-D) analytical method based on the amplitude attenuation (Ar) and 1-D numerical method were used to interpret the temperature. As a result, streambed fluxes of a total of 50 sites in the braided channel are obtained. From the results we can know the magnitude and direction of streamed flow velocity are spatially variable, even within a 1-m distance. Then, this study summarizes five bedform-driven flux patterns: ① downward flow driven by the head difference between groundwater and stream, ② downward flow related to a meter-scale pool, ③ a transition from upward to downward flow associated with a centimeter-scale riffle, ④ horizontal flow in braided bars and ⑤ upward flow driven by vegetation roots. Overall, multiple physical mechanisms together contributed to the complex streambed flow system, which reflected great challenges for the scaling up of point-in-space seepage flux.

Differences in methods of quantifying the vertical hyporheic flow for streambank flow field

One-dimensional analytical methods are generally used to estimate the vertical hyporheic velocity, and inevitably yield values that differ from the true values when assumptions are not satisfied. In this study, numerical simulations were used to determine the amount of errors in the vertical hyporheic flow from several 1D analytical methods, including the solutions from amplitude ratio, phase shift of temperature, and hydraulic gradient with depth, under gaining and losing conditions. Results demonstrate that the velocity at the shallow layer is generally higher than the velocity at the deeper layer. Horizontal flow dominates the hyporheic exchange in the streambank-aquifer continuum at distances further away from the central channel. The amplitude ratio method and gradient method estimate the vertical velocity well when the vertical flow dominates the hyporheic flow and the flow is upwelling; otherwise, these two methods yield very inaccurate results. The amplitude ratio method and phase shift method yield better results compared with the gradient method for the streambank area. Our simulations indicate that two or more 1D analytical methods should be used in conjunction, and that the multi-dimensional hydraulic heads should be measured via an appropriate monitoring network to more accurately understand the hyporheic flow of a streambank.

A new method for rapid shock loss evaluation and reduction for the optimization design of a supersonic compressor cascade

A one-dimensional analytical shock loss prediction method was proposed to tailor the shock system, i.e. the strength of the first and second passage shock, and reduce the shock loss in a supersonic cascade. To develop the one-dimensional analytical model, the shock system in a supersonic cascade was divided into four processes which can be seen in most supersonic compressor cascade, i.e. the flow upstream the extending-external shock, the flow between the extending-external shock and the first passage shock, the accelerating flow from the first passage shock to the second passage shock, and the flow downstream of the second passage shock. Based on some flow assumptions and experimental empirical correlations, the complex flows, containing the shock system, in the blade passage of a supersonic compressor cascade could be described with one-dimensional relationships, which can be used to predict shock losses along the flow passage rapidly and determine the shock system improving direction for achieving lower shock loss while keeping the same cascade static pressure ratio. In order to validate the one-dimensional analytical method, the shock system of two supersonic cascades ARL-SL19 and DLR-PAV-1.5 are modified based on the analysis of the model. The modified cascades achieved about 29% and 25% reduction of shock loss at redesign point compared with baseline cascades, respectively.

A one-dimensional analytical calculation method for obtaining normal shock losses in supersonic real gas flows

The calculation of isentropic flow and normal shock waves of real gases are important, especially in the preliminary design of turbo-machinery and test rigs. In an ideal gas, the relations for one-dimensional isentropic flow and normal shock waves are well known and can be found in standard textbooks. However, for fluids exhibiting strong deviations from the ideal gas assumption universal relations do not exist due to complex equations of state. This paper presents a analytical method for the prediction of isentropic real gas flows and normal shock waves, based on the Redlich-Kwong (RK) equation of state. Explicit expressions based on a series expansion for describing isentropic flow of Novec™ 649 are compared to Refprop data and ideal gas equations. For moderate pressures the RK method is in very good agreement with the Refprop data, while the ideal gas equations fail to predict the real gas behaviour. The same observations are made for normal shock calculations, where both real gas methods yield very close results. Especially the predicted stagnation pressure losses across a shock wave are in excellent agreement.

Application of Discriminant Analysis in Monitoring the Wear Particles in the Engine Oil

Multi-dimensional analysis does not include the conventional statistical techniques used in the operating reliability of the machine, where it is much more appropriate than the one-dimensional analytical method. The article deals with monitoring the wear particles in the tractor Zetor 8641 Forterra to pherograph creating pherographical footprint, in which the engine is in critical condition. The experimental part focuses on the trend curve fitting wear evaluated from individual particle analysis tests conducted to permit the monitoring of internal combustion engines (especially diesel). Theoretical assumptions about the relationships between selected parameters of motor oils and knowledge of individual material components allow to reliably determine the accrued failure due to the increase of wear metals in the oil and signal the increased engine wear in a timely manner and to draw attention to the approaching critical condition of the machine. By applying multi-dimensional statistical data in the measurement of wear metals enabled uncovering the links and structure of the tribodiagnostic parameters and sampling the oil, which also helps to determine deeper conclusions depending on the material identification impurities.

헬름홀쯔 공명기에서 외부로의 누출

The effect of external leakage on the acoustic performance of Helmholtz resonators is experimentally and numerically investigated. The transmission loss of the Helmholtz resonator with a circular perforated hole is measured by using an impedance tube setup. The experimental results are then compared with one-dimensional analytical and three-dimensional numerical results. As the size of the hole increases, the peak of the transmission loss shifts to higher frequency, especially for the holes on the cavity. While the transmission loss is almost independent of the location of the hole on the cavity, the impact of the hole location on the neck on the transmission loss is not negligible. The results show that one-dimensional analytical method can predict the overall trends, whereas three-dimensional numerical method is necessary for more accurate predictions.

Electro-thermo-mechanical behaviors of FGPM spheres using analytical method and ANSYS software

A hollow sphere made from functionally graded piezoelectric material (FGPM) such as PZT_4 has been considered. One-dimensional analytical method for electro-thermo-mechanical response of symmetrical spheres is used. For asymmetric three-dimensional analysis, ANSYS finite element software is employed in this study. Loading is combination of internal and external pressures, a distributed temperature field due to steady state heat conduction and a constant electric potential difference between its inner and outer surfaces for analytical solution. In three-dimensional solutions closed and open spheres with different boundary conditions subjected to an internal pressure and a uniform temperature field are studied. All mechanical, thermal and piezoelectric properties except the Poisson’s ratio are assumed to be power functions of radius. It has been found from analytical solution that the induced radial and circumferential stresses of an imposed electric potential is similar to the residual stresses locked in the homogeneous sphere during the autofrettage process of these vessels. It has been concluded from the three-dimensional analysis that the magnitudes of effective stresses at all node points are higher for the clamped–clamped boundary condition and are lower for the simply–simply supported condition.

Correcting lateral heat conduction effect in image-based heat flux measurements as an inverse problem

The image deconvolution method is developed, which is coupled with the one-dimensional (1D) analytical inverse method to calculate more accurate heat flux fields by correcting the lateral heat conduction effect in image-based surface temperature measurements. The theoretical foundation is a convolution-type integral equation with a Gaussian filter (kernel) that relates a heat flux field obtained by using the 1D inverse method on a surface to the true heat flux field. The accuracy of this method is evaluated and the standard deviation in the Gaussian filter is determined for different materials through simulations. This method is used to calculate heat flux fields in temperature-sensitive-paint measurements on a 7°-half-angle circular cone at Mach 6 in a short-duration hypersonic wind tunnel. In addition, a simple method is proposed to solve a projection problem associated with image deconvolution for a highly curved developable surface.