Asymmetric Curves Research Articles

Enhancing Security by Using GIFT and ECC Encryption Method in Multi-Tenant Datacenters

Data security and user privacy have become crucial elements in multi-tenant data centers. Various traffic types in the multi-tenant data center in the cloud environment have their characteristics and requirements. In the data center network (DCN), short and long flows are sensitive to low latency and high throughput, respectively. The traditional security processing approaches, however, neglect these characteristics and requirements. This paper proposes a fine-grained security enhancement mechanism (SEM) to solve the problem of heterogeneous traffic and reduce the traffic completion time (FCT) of short flows while ensuring the security of multi-tenant traffic transmission. Specifically, for short flows in DCN, the lightweight GIFT encryption method is utilized. For Intra-DCN long flows and Inter-DCN traffic, the asymmetric elliptic curve encryption algorithm (ECC) is utilized. The NS-3 simulation results demonstrate that SEM dramatically reduces the FCT of short flows by 70% compared to several conventional encryption techniques, effectively enhancing the security and anti-attack of traffic transmission between DCNs in cloud computing environments. Additionally, SEM performs better than other encryption methods under high load and in large-scale cloud environments.

Probing the effect of nitro-substituents in the modulation of LUMO energies for directional electron transport through 4d6 ruthenium(II)-based metallosurfactants.

Electron-withdrawing nitro-substituents were installed onto terpyridine- and phenanthroline-based metallosurfactants with 4d6 ruthenium(II), which were deposited as Langmuir-Blodgett monolayers aiming to study the feasibility of charge transport in Au|LB|Au junctions. The nitro groups are intended to modulate the energy of the frontier molecular orbitals to near to, or match that of Fermi levels in the gold electrodes. A series of heteroleptic metallosurfactants [RuII(C18OPh-terpy)(X-terpy)](PF6)2 and [RuII(C18OPh-terpy)(X-phen)Cl]PF6 were synthesized, where C18OPh-terpy is the 4'-[4-(octadecyloxy)phenyl]-2,2':6',2''-terpyridine amphiphile common to all species, X-terpy is a terpyridine with-H (1) or-phenyl-NO2 (2) and X-phen is a phenanthroline with-H (3) or-NO2 (4) groups. These metallosurfactants were characterized by experimental and computational methods, and the presence of nitro groups affect more affordable reductions at less negative potentials, as well as slightly more positive oxidations, these changes are less pronounced in species 2 than in 4. Species 1 and 2 showed limited Pockels-Langmuir and Langmuir-Blodgett film formation with lower collapse pressure of 27 mN m-1. In contrast, metallosurfactants 3 and 4 showed enhanced hydrophilicity indicated by higher collapse pressures of ca. 36 mN m-1. The LB monolayers of 3 and 4 were deposited on gold electrodes to form Au|LB|Au junctions and electron transport was measured as I/V curves. The NO2-bearing species 4 showed asymmetric curves associated with directional electron transport with amplitudes up to -2.0 nA and rectification ratios from 5 to 26 between -1 to +1 V and from 3 to 14 between -3 to +3 V.

Overlap classification-based and kinematically coordinated corner rounding using double asymmetrical transitions for five-axis short-segmented tool path

For traditional corner rounding methods that adopt a pair of symmetrical and asymmetrical transition curves to round the corners in tool tip position and tool orientation, there are still two critical issues remain unsolved. One is the overlaps between adjacent transition curves have to be eliminated specifically to avoid the excessive approximation of the transition curves to the corners, the other is the asynchronous motions between tool tip position and tool orientation on the transition curves need to be addressed in addition to achieving smoothness at the junctions between transition curves and linear segments. For solving these two issues, this paper proposes the overlap classification-based and kinematically coordinated double asymmetrical transitions to round the corners. In this method, the overlaps between adjacent transition curves in tool tip position and tool orientation are first classified. Then, parameter synchronization is derived analytically and a targeted overlap elimination strategy is also proposed, so that the transition lengths without forcing the transition curves over-approach the corners are determined. Furthermore, to alleviate the asynchronous motions, the kinematics coordination between tool tip position and tool orientation is introduced, which is utilized to further evaluate the transition lengths to improve the kinematics performance of rotary axes. Finally, the computer simulations and machining experiment both demonstrate that our method can improve the feedrate and achieve the low acceleration and jerk of rotary axes indeed.

Micro-Vibration Signal Denoising Algorithm of Spectral Morphology Fitting Based on Variational Mode Decomposition

Environmental micro-vibration has a significant impact on the proper functioning of semiconductor production and testing equipment such as the Czochralski growth furnace, polishing machine, photoetching machine, scanning electron microscope, etc. Low-frequency micro vibration has a significant influence on the normal operation of high-precision machining and testing equipment, and even causes irreversible damage to the equipment. Therefore, the micro-vibration test has important theoretical significance and engineering value for guiding the vibration isolation design of an electronic industrial workshop and ensuring the stable operation of various precision equipment in the workshop. As the observed acceleration signal is affected by noise introduced by the acceleration sensor itself, the signal processing circuit, the external power supply and interference from environmental factors, direct integration operations can lead to problems such as baseline drift and signal distortion in the calculation results. Aiming at the problem of noise interference in the micro-vibration measurement process, this paper proposed a micro-vibration signal denoising algorithm of spectral morphology fitting based on variational mode decomposition. The observed acceleration signal is decomposed into several orders of finite bandwidth intrinsic mode function components. The asymmetric Gaussian mixture model is used to complete the fitting of the spectral curves of each order of intrinsic mode function components. We can obtain the relevant parameters of the asymmetric Gaussian mixture model curves to complete the division of the effective information frequency band and finally achieve the denoising of the observed acceleration signal. Finally, the algorithm of this paper is compared with traditional denoising algorithms through numerical simulation examples and comparative experiments on denoising effects. The results show that the proposed algorithm has higher accuracy and anti-noise ability.

Heat transfer enhancement in the novel wavy shaped heat exchanger channel with cylindrical vortex generators

The enhancement characteristics of heat transfer in conjunction with a low pressure drop were experimentally and numerically investigated for the novel geometry wavy shaped heated channel with cylindrical vortex generators. To visualize the temperature distribution there was used the holographic interferometry method while the Ansys Fluent software was used to evaluate the temperature, velocity, and pressure field in the wavy channel. The study is focused on the analysis of the heat transfer coefficients, Nusselt numbers, thermal performance, Colburn factor, and friction factor for the wavy channel and the wavy channel with cylindrical vortex generators of 15 mm diameter located in five different horizontal positions. Moreover, we have performed a comparison with the smooth channel. The results are presented for the surface temperature Ts = 318.15 K, Reynolds number 778 ≤ Re ≤ 7,930, and channel height 0.04 m ≤ H ≤ 0.06 m. At the wavy channel with position “2” of cylindrical vortex generators for the channel height of 0.04 m and Re = 1,669 was noticed the maximum thermal performance factor TPF́ = 0.8167. For this configuration, the novel asymmetric curve geometry in combination with cylindrical vortex generators at position “2” brought the enhancement of the Colburn factor j by 2.48 and 3.28 times compared to the wavy and smooth channels, respectively. The new correlating equations for all investigated channel height and volumetric flow rate in the range of 10 m3/h to 50 m3/h were created. The results show that inserting cylindrical vortex generators into the investigated channels is significant to achieve more efficient heat transfer and thus reducing energy consumption.

A Robust and Anonymous Three-Factor Authentication Scheme Based ECC for Smart Home Environments

With the rapid development of the Internet of Things (IoT) industry, the smart home is fully integrated with people’s shelter and transportation, which facilitates people’s daily life. A smart home without a security authentication mechanism will inevitably cause a series of security threats. This is essentially a problem of symmetry model worth solving. In fact, researchers have designed various authentication schemes to verify the identity of users and to ensure smart devices can be legally accessed through authorization in the smart home. In 2021, Yu proposed a three-factor anonymous authentication scheme for smart homes using lightweight symmetric encryption primitives and stated that their scheme is resistant to various known security attacks. However, after careful analysis, we found that Yu’s scheme needs further improvement in node capture attack and offline password guessing attack and that forward security cannot be guaranteed. Therefore, we first design a robust three-factor anonymous authentication scheme for smart homes based on asymmetric encryption Elliptic Curve Cryptography (ECC). Then, we perform formal and informal security analysis in which the formal analysis tools include Burrows-Abadi-Needham (BAN) logic and Scyther simulation tool to prove that the proposed scheme can achieve user anonymity, untraceability, and session key forward security. Meanwhile, mutual authentication is performed, and the scheme is resistant to all known attacks described in this article. Finally, a performance comparison is made in terms of efficiency, which shows that our scheme can have certain advantages with those newly designed schemes, achieve a delicate balance in performance and safety, and is more practical for the real smart home environment.

A Review of Buckling Restrained Braces

One of the problems of common bracing system is their buckling against compressive loads, which reduces the amount of energy loss of the structure. Buckling Restrained Brace (BRB) have solved the problem of conventional braces by eliminating the overall buckling of the brace under pressure. Buckling Restrained Braced Frame (BRBF) is a new type of bracing system that has been widely used in recent years. Nowadays the use of buckling restrained braces, due to having more advantages compared to conventional steel braces, have received the attention of researchers and engineers that these advantages include: high ductility, more energy loss, no overall and local buckling, and also having a symmetrical cyclic curve. This type of bracing is considered as one of the effective systems for dealing with lateral loads caused by the earthquake. Disadvantages in the seismic behavior of conventional braces, such as ductility and low energy loss, general and local buckling, as well as having an asymmetric cyclic curve, have provided grounds for its modification or exclusion from the seismic design process. Buckling restrained braces are a type of energy loss system that, in addition to providing high lateral stiffness, increase the formability and energy loss of the structure. The use of this type of braces is allowed in the regulations of some countries. But in some other countries, including Iran, it has not been mentioned. According to the seismicity of the country and the increasing use of these structures in the world, the use and localization of this type of bracing system in Iran is inevitable, and the entry of this lateral bearing system into the design regulations, especially the earthquake regulations of Iran, is mandatory. The results of the analysis show that the energy loss capacity of the buckling restrained brace is about 5 times the energy loss capacity of the normal brace.

Re-parameterization of the asymmetric model for fungal spore germination

The asymmetric model (Dantigny et al., 2011, A new model for germination of fungi, International Journal of Food Microbiology, 146, 176–181) is capable to fit both symmetric and asymmetric curves of fungal spore germination. However, the shape parameter in the asymmetric model must be derived from a regression of the model with experimental data of fungal spore germination, thus the asymmetric model can fit spore germination under tested conditions only. In this paper, to solve this limitation, the previously proposed shape parameter-based asymmetric model has been replaced by using the pure biological parameter-based asymmetric model as: P=Pmax·1–11+tτ4τ·μPmax, where P is the percentage of germinated spores at time t, Pmax is the maximum percentage of germinated spores, τ is the germination time (the time that P = 0.5Pmax), and μ is the slope of fungal spore germination at t = τ, representing the rate of fungal spore germination. The modified asymmetric model was validated against the germination data of six fungal species collected from the literature. The results showed that the modified asymmetric model described the spore germination of all fungi studied well. Moreover, the τ and μ in the modified asymmetric model at various environmental conditions were estimated properly via the Cardinal Model with Inflection. This solved the limitation of the previous asymmetric model. So, it can be concluded that the modified asymmetric model is an improvement over the previous asymmetric model for predicting fungal spore germination.

Application of general unit hydrograph model for marathon finish time distributions

The marathon finish time distribution is the probability distribution of the time a group of runners completes a marathon race. The knowledge of this distribution is required to optimize a running process when planning and operating a marathon; it is also required to compare different marathons and evaluate individual running performance. This research demonstrated that the marathon finish time distribution can be described by the general unit hydrograph model from applied hydrology. Specifically, we found that marathon finish time data, in terms of distribution density, often show a positively skewed distribution, which implies that a few runners are superfast, many runners are very slow, and most runners are between the two extremes. This asymmetrical feature is similar to a unit hydrograph that describes rainfall-runoff processes in watersheds. We thus hypothesized that the marathon finish time distribution follows Guo’s three-parameter general unit hydrograph model. To test this hypothesis, we fit the general unit hydrograph model to the 2013–2021 New York City (NYC) Marathon finish time distribution data, resulting in determination coefficients r2≥0.9997. We next validated the proposed model with the world marathon database including 35 million results in 2000–2021 from more than 28,000 long-distance foot races, which was then compared with the NYC marathon data. According to the two inflection times of the finish time density function (asymmetrical bell curve) of the world marathons, we classified all marathoners into three categories: super runners who finish before the left inflection time; endurable runners who finish after the right inflection time; and fast runners who finish between the two inflection times. Finally, we compared the general unit hydrograph model and two typical asymmetrical distribution functions with the world marathon data and found that the proposed model describes the data better.

Fixed bed adsorption of water and air contaminants: analysis of breakthrough curves using probability distribution functions

Simple fixed bed models such as the Bohart–Adams and Thomas equations are often used to describe the breakthrough characteristics of water and air contaminant adsorption in fixed bed adsorbers. However, these popular models are confined to correlating highly symmetric breakthrough curves. The present study explores the feasibility of using two probability distributions (normal and log-normal) to track asymmetric breakthrough curves for water and air contaminant adsorption in fixed bed columns (ciprofloxacin, ammonium, hydrogen chloride, and hydrogen sulfide). The normal and log-normal probability distributions provided accurate fits to the slightly asymmetric ciprofloxacin breakthrough curve. They also provided a good representation of the overall shape of the ammonium breakthrough curve, but failed to describe the leakage of ammonium during the initial period of column operation. The log-normal distribution was able to match the asymmetric HCI and H2S breakthrough curves. The normal distribution, by comparison, failed to describe these two asymmetric breakthrough curves. Because the log-normal distribution has a floating inflection point, it was very effective in describing the asymmetric HCI and H2S breakthrough curves that were sharp initially and then broadened significantly as the column approached saturation. The ability of the normal distribution to track such asymmetric breakthrough data was impeded by its invariant inflection point.

Approaching to the stable transportation based on motion profile phases for material handling system

Transportation is a critical part of logistics in any economy. In the context of industrialization and modernization, a solution to enable utilization of autonomous vehicles that work with uncertain factors, high speed, and continuous motion is urgent. The anti-vibration control of this system plays a vital role in avoiding accidents, especially when sharing space with humans. Therefore, in this paper, non-vibration control strategies, such as the linear motion profile (LMP), symmetric motion curve (SMC), and asymmetric motion curve (ASMC), based on the phases of motion profiles, are investigated for a lifting type of carrier. Firstly, the system modelling of both the vehicle and cargo is conducted. Secondly, by analysing the dynamic characteristics, the motion performance in both the acceleration phase and deceleration phase is achieved. Several constraints are validated in order to maintain the stable motion. In the experiments, four cases including a test without the algorithm and with the algorithm with LMP, SMC, and ASMC are examined. From these results, the peak acceleration of these schemes, LMP, SMC, and ASMC, respectively, decrease by 28.5%, 20.3%, and 10.1% compared with the case without the algorithm. The contributions of this research are (i) to analyse the poles and zeros for a load–vehicle system with respect to its dynamic characteristics, (ii) to propose a vibration attenuation control scheme based on the classification of the motion phases, and (iii) to employ various smoothing profiles to demonstrate the comparative performance. These results can be widely applied to the sustainability of not only the logistics field but also digital trade.

Temporal variation and influencing factors of albedo in a deciduous broad-leaved forest

In situ measurement of albedo is important for estimating ecosystem energy budget and its remote sensing application. However, the measurement method of albedo on sloping land is limited and the difference in temporal variation in albedo between visible and near-infrared bands remains unclear. Taking a deciduous broad-leaved forest at the Maoershan Forest Ecological Station in Northeast China as an example, we explored the temporal variation and influencing factors of albedo for three bands: incident and reflected solar radiation (SR, 300-2800 nm), photosynthetically active radiation (PAR, 400-700 nm), and near infrared radiation (NIR, 700-2800 nm). The temporal difference in albedo measurements between the two installation methods of radiometers was analyzed. The results showed that, in sunny days, the diurnal variation in SR and NIR albedo had an asymmetric U-shaped curve around the local noon, while PAR increased from sunrise to sunset. In cloudy days, the albedo decreased sharply and then tended to be stable. The measurement with parallel sensors to the slope increased the daily mean value of albedo, but reduced the daily asymmetry of SR and NIR. For the whole growing season, the maximum albedos of SR, NIR and PAR in horizontal measurement were 0.16, 0.27 and 0.11, respectively, and the minimums were 0.07, 0.11 and 0.03, respectively. Albedo in the SR and NIR wavebands increased first and then decreased (the peak value was in July), while PAR showed a contrasting pattern. SR albedo was mainly controlled by NIR rather than PAR. The contribution of the influencing factors was ranked in the order of normalized difference vegetation index (61.7%-78.5%, representing leaf area index) > solar altitude angle (15.4%-36.9%) > clearness index (0.4%-36.9%).

Multifractal Features of Particle-Size Distribution and Their Relationships With Soil Erosion Resistance Under Different Vegetation Types in Debris Flow Basin

Understanding the influence of vegetation types on soil particle-size distribution (PSD) is essential to evaluate the effects of sediment control by vegetation restoration. In this work, we studied the effects of different vegetation types, including bare land, meadow, shrub and forest on soil PSD in Jiangjiagou gully, Yunnan province, China. A total of 60 soil samples were collected and analyzed for soil particle size distribution using the laser diffraction method. Fractal theory was used to calculate multifractal parameters. The volume fraction of silt particles in shrub and forest is significantly higher than that in bare land, meadow, whereas the total volume fraction of sand particles in bare land and meadow exceed that in shrub and forest. The soil particle size distribution along soil layers has no significant difference in each vegetation type. The volumetric fractal dimension is significantly higher in forest and shrub than in bare land and grassland, but there is no significant difference between forest and shrub. In addition, soil erosion resistance exhibits significant differences of forest > shrub > grassland > bare land. Multifractal parameters are highest in bare land except for multifractal spectrum values (f (αmax) and f (αmin)) and the maximum value of singularity index (αmin). All generalized dimensions spectra curves of the PSD are sigmoidal, whereas the singular spectrum function shows an asymmetric upward convex curve. Furthermore, soil erosion resistance has significant relationships with multifractal parameters. Our results suggest that multifractal parameters of the soil PSD can predict its anti-ability to erosion. This study also provides an important insight for the evaluation of soil structure improvement and the effects of erosion control by vegetation restoration in dry-hot valley areas.

Flexible Bayesian modelling in dichotomous item response theory using mixtures of skewed item curves.

Most item response theory (IRT) models for dichotomous responses are based on probit or logit link functions which assume a symmetric relationship between the probability of a correct response and the latent traits of individuals taking a test. This assumption restricts the use of those models to the case in which all items behave symmetrically. On the other hand, asymmetric models proposed in the literature impose that all the items in a test behave asymmetrically. This assumption is inappropriate for great majority of tests which are, in general, composed of both symmetric and asymmetric items. Furthermore, a straightforward extension of the existing models in the literature would require a prior selection of the items' symmetry/asymmetry status. This paper proposes a Bayesian IRT model that accounts for symmetric and asymmetric items in a flexible but parsimonious way. That is achieved by assigning a finite mixture prior to the skewness parameter, with one of the mixture components being a point mass at zero. This allows for analyses under both model selection and model averaging approaches. Asymmetric item curves are designed through the centred skew normal distribution, which has a particularly appealing parametrization in terms of parameter interpretation and computational efficiency. An efficient Markov chain Monte Carlo algorithm is proposed to perform Bayesian inference and its performance is investigated in some simulated examples. Finally, the proposed methodology is applied to a data set from a large-scale educational exam in Brazil.

The Modified Brière Equation and Its Applications.

The Brière equation (BE) is widely used to describe the effect of temperature on the development rate of insects, and it can produce both symmetrical and asymmetrical bell-shaped curves. Because of its elasticity in curve fitting, the integrated form of BE has been recommended for use as a sigmoid growth equation to describe the increase in plant biomass with time. However, the start time of growth predicted by the sigmoid growth equation based on the BE is not completely comparable to empirical crop growth data. In the present study, we modified the BE by adding an additional parameter to further increase its elasticity for data fitting. We termed this new equation the modified Brière equation (MBE). Data for the actual height and biomass of 15 species of plants (with two cultivars for one species) were fit with the sigmoid growth equations based on both the BE and MBE assuming that the growth start time was zero for both. The goodness of fit of the BE and MBE sigmoid growth equations were compared based on their root-mean-square errors and the corresponding absolute percentage error between them when fit to these data. For most species, we found that the MBE sigmoid growth equation achieved a better goodness of fit than the BE sigmoid growth equation. This work provides a useful tool for quantifying the ontogenetic or population growth of plants.

Rapid detection of the irinotecan-related UGT1A1*28 polymorphism by asymmetric PCR melting curve analysis using one fluorescent probe.

BackgroundDetermination of UGT1A1 (TA)n polymorphism prior to irinotecan therapy is necessary to avoid severe adverse drug effects. Thus, accurate and reliable genotyping methods for (TA)n polymorphism are highly desired. Here, we present a new method for polymerase chain reaction (PCR) melting curve analysis using one fluorescent probe to discriminate the UGT1A1*1 [(TA)6] and *28 [(TA)7] genotypes.MethodsAfter protocol optimization, this technique was applied for genotyping of 64 patients (including 23 with UGT1A1*1/*1, 22 with *1/*28, and 19 with *28/*28) recruited between 2016 and 2021 in China‐Japan Friendship Hospital. The accuracy of the method was evaluated by comparing the results with those of direct sequencing and fragment analysis. The intra‐ and inter‐run precision of the melting temperatures (Tms) were calculated to assess the reliability, and the limit of detection was examined to assess the sensitivity.ResultsAll genotypes were correctly identified with the new method, and its accuracy was higher than that of fragment analysis. The intra‐ and inter‐run coefficients of variation for the Tms were both ≤0.27%, with standard deviations ≤0.14°C. The limit of detection was 0.2 ng of input genomic DNA.ConclusionThe developed PCR melting curve analysis using one fluorescent probe can provide accurate, reliable, rapid, simple, and low‐cost detection of UGT1A1 (TA)n polymorphism, and its use can be easily generalized in clinical laboratories with a fluorescent PCR platform.

Transport and targeted binding of Pluronic-coated nanoparticles in unsaturated porous media

The effectiveness of most in situ remedial technologies, including nanoremediation, lies on successful delivery of reagents to a subsurface target treatment zone. Targeted delivery of engineered nanoparticles (NPs) to treat petroleum hydrocarbons present in the unsaturated zone requires an understanding of their transport behaviour in these systems. A series of column experiments explored the effect of initial water saturation, flowrate, input dosage, and porous medium texture on the transport of iron oxide or cobalt ferrite NPs coated with an amphiphilic co-polymer, as well as their targeted attachment to a crude oil zone. As the initial water content increased with a concomitant reduction in air saturation, the degree of tailing present in the NP breakthrough curves (BTCs) reduced, and the mass of NPs recovered increased. Air saturation is positively correlated with the magnitude of air-water interfaces, which provide additional NP retention sites. At a lower injection flow rate, NP retention increased due to a longer residence time and comparatively high air saturation. NP transport behaviour was not sensitive to NP injection dose over the range tested. Increased retention and retardation of the NP BTC was observed in sediments with a higher clay and silt content. NPs coated with a lower concentration of a Pluronic block co-polymer to promote binding were preferentially retained within the crude oil zone. To simulate the asymmetrical NP breakthrough curves observed from the unsaturated systems required the use of a model that accounted for both mobile and immobile flow regions as well as NP attachment and detachment with nonlinear Langmuirian blocking. This model allowed examination of attachment and detachment rate coefficients which captured NP interaction with the porous medium and/or crude oil. It was found that the initial water saturation and flow rate did not have an appreciable impact on the NP attachment rate coefficient, while it increased by ~10× with increasing clay and silt content, and by ~100× in the presence of crude oil, indicating preferential NP attachment within the crude oil zone. As a result of the lower NP polymer concentration coating used to promote increased attachment to crude oil, higher retention was observed near the column inlet and was captured quantitatively by adding a depth-dependent straining term to the model. This retention behaviour represents a combination of irreversible attachment at the air-water interfaces and straining near the column inlet enhanced by the formation of NP aggregates. The detachment rate coefficient decreased with a lower initial water saturation and flowrate, but increased with higher clay and silt content. The findings from this study contribute to our understanding of the transport and binding behaviour of Pluronic-coated NPs in unsaturated conditions and, in particular, the role of initial water content, flowrate and porous medium texture. Demonstrated delivery of NPs to a target zone is an important step towards expanding the utility of NPs as treatment reagents.

Bayesian inversion of laboratory experiments of transport through limestone fractures

In this study, a novel experimental setup is proposed for which a column filled with glass beads and parallelepiped-shaped limestone beams is used to reconstruct a multiple fracture limestone media. The proposed setup produces asymmetric breakthrough curves (BTCs) that are consistent with the shape expected from the past field and lab-scale studies. Three transport experiments have been conducted under fast, medium, and slow flow velocity conditions.The research focuses on parameter and state estimation using Bayesian inference via Markov Chain Monte Carlo (MCMC) sampler, investigating the degree to which three models of transport through fractured media can reproduce the experimental results under the three flow conditions. The first transport model, named ADE, is based on the equivalent porous medium (EPM) approach and corresponds to the linear advection dispersion equation (ADE). The second model, named FOMIM (first-order mobile immobile), is based on the mobile/immobile approach and uses the dual porosity model with a linear first-order transfer between mobile and immobile regions. The third model, named NLMIM (non-linear mobile-immobile), uses a nonlinear transfer function between these two regions.The results of the three models show that almost all the unknown model input parameters can be well-estimated with narrow confidence intervals using the MCMC method. With respect to state estimation, the ADE model fails to reproduce correctly the tail of the BTCs observed under slow and medium flow conditions. The FOMIM model improves the tailing of the BTCs, but significant discrepancies remain between simulated and measured concentrations. The NLMIM model with velocity-dependent parameters is the only model that captures BTCs under all three conditions of slow, medium, and fast flow velocities.

Design and Performance Analysis of a Dynamic Magnetic Resonance Imaging-Compatible Device for Triangular Fibrocartilage Complex Injury Diagnosis.

Pain and injury of the triangular fibrocartilage complex (TFCC) due to overuse or trauma are commonly diagnosed through static MRI scanning, while TFCC is always involved in radial and ulnar deviation of the wrist. To the best of our knowledge, a dynamic MRI diagnostic method and auxiliary tool have not been applied or fully developed in the literature. As such, this study presents the design and evaluation of a dynamic magnetic resonance imaging (MRI) auxiliary tool for TFCC injury diagnosis. First, 3D scanning and Python are used to measure and fit the radial and ulnar deviation trajectories of healthy participants and patients. 3D printing is then used to manufacture the auxiliary tool for dynamic MRI, and dynamic MRI diagnosis is then conducted to explore the clinical effect. The radial and ulnar deviation trajectory is presented as an asymmetric curve without an obvious circular centre, and the results indicate that the designed auxiliary device meets the requirements of the ulnar and radial movements of the human wrist. According to the MRI contrast test results, the image quality score of patients wearing the auxiliary device is higher than for those without. Such devices could assist clinicians in the diagnosis of TFCC damage, and our method could not only serve as the reference standard for clinical noninvasive diagnosis but also help in understanding the disease and improving the accuracy of TFCC diagnosis.

New Polarimetric Data for the Galilean Satellites: Europa Observations and Modeling

This paper is dedicated to a long-standing problem of the shape of the negative branch of polarization (NBP) for Jupiter's moon Europa, determination of which is crucial for the characterization of the icy regolith on this satellite and similar objects, as well as for further progress in understanding light scattering by particulate surfaces. To establish the shape of Europa's NBP, in 2018–2021 we accomplished high-precision disk-integrated polarimetry of Europa in the UBVR I bands using the identical two-channel photoelectric polarimeters mounted on the 2.6 m Shajn reflector of the Crimean Astrophysical Observatory and the 2 m telescope of the Peak Terskol Observatory. We found that the polarization dependence on the phase angle in each filter is an asymmetric curve with a sharp polarization minimum at phase angle , after which the polarization degree gradually increases to positive values, passing the inversion angle at α inv ≈ 6° − 7°. Within the error limits, the parameters P min, , and α inv of the NPB are independent of the wavelength in the visible spectrum. The polarization curve clearly demonstrates the so-called polarization opposition effect (POE). Our analysis of the previous and new polarimetric observations of Europa allows us to conclude that the POE is caused by coherent backscattering of sunlight on microscopic icy grains covering Europa’s surface. Computer modeling with the numerical radiative transfer coherent backscattering method demonstrates that the best fit to the polarimetric observations and geometric albedo of Europa is provided by a regolith layer of elementary single-scattering albedo ∼0.985 and extinction mean free path length 2π l/λ eff ≈ 150, λ eff representing the effective wavelength in the UBVR I spectral bands.