Numerical Study Research Articles

A 2TLNS-based exponential TODIM-EDAS approach for evaluating sustainable development of cross-border e-commerce platforms under uncertainty

In the context of globalization, cross-border e-commerce platforms have become the main way for enterprises to achieve international trade transformation and overseas investment. From this, it can be seen that cross-border e-commerce platforms are of great importance to the development of enterprises, and the development of cross-border e-commerce platforms is also a necessary choice for the development of the times. In the new era, in order to make cross-border e-commerce platforms better serve enterprises and bring economic benefits to their development. The sustainable development capability evaluation of third-party cross-border e-commerce (TPCBEC) platform is a MAGDM. Recently, the Exponential TODIM (ExpTODIM) technique and Evaluation Based on Distance from Average Solution (EDAS) technique has been employed to cope with MAGDM issues. The 2-tuple linguistic neutrosophic sets (2TLNSs) are employed as a tool for portraying uncertain information during the sustainable development capability evaluation of TPCBEC platform. In this paper, the 2-tuple linguistic neutrosophic number Exponential TODIM-EDAS (2TLNN-ExpTODIM-EDAS) technique is implemented to manage the MAGDM under 2TLNSs. Finally, a numerical study for sustainable development capability evaluation of TPCBEC platform is constructed to validate the implemented technique. Thus, the main advantages of the proposed 2TLNN-ExpTODIM-EDAS technique are outlined: (1) the proposed 2TLNN-ExpTODIM-EDAS technique not only handles the distances information from the 2TLNNAS, but also portrays the DMs’ psychological behavior during the sustainable development capability evaluation of TPCBEC platform. (2) the proposed 2TLNN-ExpTODIM-EDAS technique analyze the behavior of the TODIM technique and EDAS technique as MADM techniques when they are hybridized.

Leaching behaviors of dissolved organic matter from face masks revealed by fluorescence EEM combined with FRI and PARAFAC

Despite numerous studies investigating the occurrence and fate of microplastics, no effort has been devoted toward exploring the characteristics of dissolved organic matter (DOM) leached from face masks mainly made of plastics and additives used in large quantities during the COVID-19 pandemic. By using FTIR, UV–vis, fluorescence EEM coupling with FRI and PARAFAC, and kinetic models of leaching experiments, we explored the leaching behaviors of face mask-derived DOM (FM-DOM) from commonly used face masks including N95, KN95, medical surgical masks, etc. The concentration of FM-DOM increased quickly at early 0–48 h and reached equilibrium at about 48 h measured in terms of dissolved organic carbon and fluorescence intensity. The protein-like materials ranged from 80.32 % to 89.40 % of percentage fluorescence response (Pi,n) were dominant in four types of FM-DOM analyzed by fluorescence EEM-FRI during the leaching experiments from 1 to 360 h. Four fluorescent components were identified, which included tryptophan-like components, tyrosine-like components, microbial protein-like components, and fulvic-like components with fluorescence EEM-PARAFAC models. The multi-order kinetic model (Radj2 0.975–0.999) fitted better than the zero-order and first-order kinetic model (Radj2 0.936–0.982) for all PARAFAC components of FM-DOM based on equations derived by pseudo kinetic models. The leaching rate constants (kn) ranged from 0.058 to 30.938 and the half-life times (T1/2) ranged from 2.73 to 24.87 h for four FM-DOM samples, following the solubility order of fulvic-like components (C4) > microbial protein-like components (C3) > tryptophan-like components (C1) > tyrosine-like components (C2) for FM-DOM from four types of face masks during the leaching experiment from 0 to 360 h. These novel findings will contribute to the understanding of the underappreciated environment impact of face masks in aquatic ecosystems.

Numerical Study of a Thermal Plume Developing in a Neutral Environment and in Interaction: Application to Fires Problems

This study focuses on the mathematical and numerical modelling of how different properties, such as channel length and hot source height, affect the flow of thermal plumes and their interaction with the surrounding environment. Studying the behaviour of a directed thermal plume flow can provide a good visualisation of the control parameters for various applications related to fires and pollutants. To determine the control parameters affecting this flow, it is imperative to initially analyse the flow through a natural convection consisting of a disc-shaped heat source at the inlet of a vertical cylinder using mathematical and numerical methods. The flow in this study is characterised by natural convection, turbulent, steady, two-dimensional and incompressible. Numerical results were obtained via computational fluid dynamics analysis, which is based on mathematical flow modelling using the system of Navier–Stokes equations and the finite volume method. The SIMPLE algorithm was used for the velocity–pressure coupling. After introducing the concept of Reynolds averaging and analysis, different RANS turbulence models are presented, particularly two-equation models, using the Ansys Fluent software. Comparison of the different profiles revealed the ideal flow control parameters. An improvement in thermal properties was observed when the height of the heat source was = 1.5 cm and the vertical length of the channel was D = 20cm.

Numerical Study of Pore Water Pressure in Frozen Soils during Moisture Migration

Frost heaving in soils is a primary cause of engineering failures in cold regions. Although extensive experimental and numerical research has focused on the deformation caused by frost heaving, there is a notable lack of numerical investigations into the critical underlying factor: pore water pressure. This study aimed to experimentally determine changes in soil water content over time at various depths during unidirectional freezing and to model this process using a coupled hydrothermal approach. The agreement between experimental water content outcomes and numerical predictions validates the numerical method’s applicability. Furthermore, by applying the Gibbs free energy equation, we derived a novel equation for calculating the pore water pressure in saturated frozen soil. Utilizing this equation, we developed a numerical model to simulate pore water pressure and water movement in frozen soil, accounting for scenarios with and without ice lens formation and quantifying unfrozen water migration from unfrozen to frozen zones over time. Our findings reveal that pore water pressure decreases as freezing depth increases, reaching near zero at the freezing front. Notably, the presence of an ice lens significantly amplifies pore water pressure—approximately tenfold—compared to scenarios without an ice lens, aligning with existing experimental data. The model also indicates that the cold-end temperature sets the maximum pore water pressure value in freezing soil, with superior performance to Konrad’s model at lower temperatures in the absence of ice lenses. Additionally, as freezing progresses, the rate of water flow from the unfrozen region to the freezing fringe exhibits a fluctuating decline. This study successfully establishes a numerical model for pore water pressure and water flow in frozen soil, confirms its validity through experimental comparison, and introduces an improved formula for pore water pressure calculation, offering a more accurate reflection of the real-world phenomena than previous formulations.

Investigation of Drilling Holes in CFRP for Aircraft Using cBN Electroplated Ball End Mill Using Helical Interpolation Motion

Investigation of Drilling Holes in CFRP for Aircraft Using cBN Electroplated Ball End Mill Using Helical Interpolation Motion

Multiportfolio Optimization: A Fairness-Aware Target-Oriented Model

Problem definition: We consider a multiportfolio optimization problem in which nonlinear market impact costs result in a strong dependency of one account’s performance on the trading activities of the other accounts. Methodology/results: We develop a novel target-oriented model that jointly optimizes the rebalancing trades and the split of market impact costs. The key advantages of our proposed model include the consideration of clients’ targets on investment returns and the incorporation of distributional uncertainty. The former helps fund managers to circumvent the difficulty in identifying clients’ utility functions or risk parameters, whereas the latter addresses a practical challenge that the probability distribution of risky asset returns cannot be fully observed. Specifically, to evaluate the quality of multiple portfolios’ investment payoffs in achieving targets, we propose a new class of performance measures, called fairness-aware multiparticipant satisficing (FMS) criteria. These criteria can be extended to encompass distributional uncertainty and have the salient feature of addressing the fairness issue with the collective satisficing level as determined by the least satisfied participant. We find that, structurally, the FMS criteria have a dual connection with a set of risk measures. For multiportfolio optimization, we consider the FMS criterion with conditional value-at-risk being the underlying risk measure to further account for the magnitude of shortfalls against targets. The resulting problem, although nonconvex, can be solved efficiently by solving an equivalent converging sequence of tractable subproblems. Managerial implications: For the multiportfolio optimization problem, the numerical study shows that our approach outperforms utility-based models in achieving targets and in out-of-sample performance. More generally, the proposed FMS criteria provide a new decision framework for operational problems in which the decision makers are target-oriented rather than being utility maximizers and issues of fairness and ambiguity should be considered. Funding: This work was supported by the Hong Kong Research Grants Council [Grants 14210821, 16204521], Leading Talent Program of Guangdong Province [Grant 2016LJ06D703], and the National Natural Science Foundation of China [Grants 71971187, 72171156, 72231002, 72331009]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2021.0363 .

Flexural Strength of RHS Perforated Lean Duplex Stainless Steel Beam at Temperature 24-900ºC

The investigation of stainless steel structures at elevated temperatures is still limited, especially to those focused on the behaviour of perforated beams. Therefore, a numerical study was conducted to investigate the behaviour and strength of cold-formed lean duplex stainless steel (CFLDSS) beams having a single web perforation that failed due to pure bending at temperatures between 24-900oC. In total, 200 square and rectangular hollow sections (RHSs), which had various cross-section sizes, hole diameters, and temperature simulations, were involved in the parametric study. The numerical study was based on the ABAQUS simulation results of the 200 specimens. The numerical model was developed based on the validated existing studies. Numerical evaluations show that the existing codified strength predictions are conservative, but it has inconsistent safety. Hence, this study suggests modifications to the existing strength prediction, which is more conservative and reliable.

Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications.

Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.

Numerical study on unsteady performance of a Wells turbine under irregular wave conditions

The axial-flow Wells turbine is one of the most widely used power take-off unit for oscillating water column wave energy converter. Despite advancements, many converters still encounter challenges such as intermittent power output and difficulty in self-starting for air turbines. The reason behind this could be attributed to the fact that previous studies primarily focused on examining the unsteady performance of air turbines at a fixed rotation speed or under ideal sinusoidal airflow conditions. To predict the unsteady responses under irregular wave conditions, a transient free-running numerical model of a Wells turbine was developed in the present work. Following the validation of experimental results, the mechanism of hysteresis was further investigated by analyzing performance parameters, time-varying details of 3D flow field, and dependence factors. Furthermore, effects of significant wave height and peak spectral period on the ability to self-start were studied.

GSG2 promotes thyroid cancer via stabilizing AURKB and activating AKT pathway.

Thyroid cancer stands out as the most prevalent endocrine cancer, with its incidence on a global rise. While numerous studies have delved into the roles of GSG2 in the progression of various malignancies, its involvement in thyroid cancer remains relatively unexplored. Therefore, this study was initiated to assess the functional importance of GSG2 in human thyroid cancer development. Our findings revealed a notable upregulation of GSG2 in both thyroid cancer tissues and cell lines, demonstrating a significant correlation with the pathological stage and patients' prognosis. Depletion of GSG2 in thyroid cancer cells resulted in suppressed malignant cell development and inhibited tumor outgrowth. Crucially, our investigation identified AURKB as a downstream gene of GSG2. GSG2 exhibited its regulatory role by stabilizing AURKB, countering SMURF1-mediated ubiquitination of AURKB. Furthermore, overexpressing AURKB restored the functional consequences of GSG2 depletion in thyroid cancer cells. Additionally, we proposed the involvement of the AKT pathway in GSG2-mediated regulation of thyroid cancer. Intriguingly, the reversal of cell phenotype alterations in GSG2-depleted cells following an AKT activator underscored the potential link between GSG2 and the AKT pathway. At the molecular level, GSG2 knockdown downregulated p-AKT, an effect partially restored after AKT activator treatment. In summary, our study concluded that GSG2 played a pivotal role in thyroid carcinogenesis, underscoring its potential as a therapeutic target for thyroid cancer.

Grouped rubber-sleeved studs–UHPC pocket connections in prefabricated steel–UHPC composite beams: Shear performance under monotonic and cyclic loadings

Prefabricated steel–ultra-high-performance concrete (UHPC) composite beams (PSUCBs) with grouped stud–UHPC pocket connections (GSUPCs) are a successful attempt of UHPC in bridge engineering, which offers significant advantages in accelerating on-site construction, enhancing structural performance, and improving environmental benefits. However, the uneven steel–concrete interfacial shear stresses distribution caused by the insufficient deformability of ordinary studs (OSs) in UHPC may result in the premature stud failure in large interfacial slippage regions. To address this issue, rubber-sleeved studs (RSSs) that wrapped rubber-sleeves around the stud roots were introduced to improve ductility and reduce the stiffness of connectors. However, the shear performance of grouped RSSs embedded in UHPC remains unclear, which hinders their application in practices. Against this background, systematic experimental and numerical studies were conducted to investigate the monotonic and cyclic shear performance of grouped RSSs–UHPC pocket connections. The results indicated that wrapping rubber-sleeve could increase the ultimate slip capacity and remained sufficient shear resistance, demonstrating great potentials of grouped RSSs–UHPC pocket connections in PSUCBs. Increasing the rubber-sleeve thicknesses and height effectively improved the ultimate slip capacity and deformation recovery, but led to the significant plastic deformation accumulation and cyclic stiffness degradation. Finally, design recommendation on rubber-sleeve configuration rationalization, ultimate shear resistance and load–slip relationship predictive models were provided.

Evaluation of metal ions and DNA recovery from the surface of fired and unfired brass ammunition to improve STR profiling.

Interest in recovering DNA from the surface of ammunition evidence for genotyping has increased over the past few years. Numerous studies have examined a variety of methods to maximize DNA recovery from these types of challenging samples, but successful DNA profiling has been inconsistent. Low amounts of DNA and PCR inhibition due to metal ions have been suggested as the leading causes of poor results; however, no study quantitatively examined the presence of metal ions at various stages of the DNA analysis workflow from DNA collection through to amplification. In this study, the effectiveness of six different DNA collection and purification methods commonly used by forensic laboratories to process brass ammunition for DNA evidence was investigated. The amount of copper, zinc, and other metals co-recovered from fired and unfired brass casings during DNA collection (using numerous soaking, swabbing, and direct PCR protocols) was quantified via Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). This same panel of metals was subsequently quantified after DNA lysis and purification steps. Results demonstrated that low amounts of DNA, DNA damage, and degradation are more detrimental to STR typing results than PCR inhibition, as metal ions were successfully removed by all DNA purification methods tested. Furthermore, the use of metal ion chelators increased the amount of DNA recovered and number of reportable STR alleles. This research informs the forensic community on the most effective way to collect and process trace amounts of biological material from brass ammunition and similar evidence.

Equine Asthma Does Not Affect Circulating Myostatin Concentrations in Horses.

(1) Background: The number of horses suffering from chronic respiratory diseases, resembling human asthma, is increasing but there is still a lack of reliable and accurate methods to detect these disorders. Numerous studies have found elevated plasma concentrations of one of the myokines, namely, myostatin (MSTN), in people suffering from severe asthma. MSTN normally inhibits myoblast proliferation and differentiation through autocrine or paracrine signals. Therefore, given the pathogenesis of asthma, we hypothesize that MSTN could be a useful biomarker of equine asthma. Thus, this study aimed to compare the concentration of MSTN in the blood plasma of fully healthy and asthmatic horses. (2) Methods: A total of 61 horses were clinically examined to confirm or exclude the occurrence of equine asthma, including bronchoalveolar lavage (BAL) fluid cytology performed on 49 horses. This study included three groups of horses, two of which were clinically healthy, and one of which was asthmatic. (3) Results: The mean circulatory MSTN concentration determined using the ELISA method in asthmatic horses was significantly higher than that in clinically healthy young Thoroughbred racehorses (p < 0.05), but it did not differ as compared to the group of healthy, adult leisure horses. (4) Conclusions: The obtained results did not unambiguously support our original hypothesis that MSTM may be a reliable marker for the early diagnosis of equine asthma. To the best of the authors' knowledge, this is the first study to analyze the plasma MSTN concentration in equine asthma patients, and therefore further studies are needed to confirm our novel findings.

Length-Weight, Length-Length Relationships and Condition Factor of &lt;i&gt;Crossocheilus diplochilus&lt;/i&gt; (Heckel) from Dal Lake of Kashmir Himalayas

Length-Length Relationships (LLRs) and Length-Weight Relationships (LWRs) are vital tools in the management of fisheries to facilitate a proper understanding of the condition of fish species and the growth pattern from different environments. Despite numerous studies on LWRs and LLRs of fish species, the majority of those have focused on the food fish creating a lacuna in the biometric assessment studies of forage fish. Against this backdrop, the current work was undertaken to estimate the LLRs, LWRs and condition factor of Crossocheilus diplochilus, a forage fish from Dal Lake of Kashmir Himalayas. The fish was reported to show negative allometric growth, attaining a maximum length of 14.8 cm and a maximum weight of 17.19 g. The overall condition factor was reported to be 0.86 ± 0.10, reflecting a poor condition of growth. The fish forms a vital trophic link of the lake, as such timely biometric studies could help in managing its stock properly.

Energy analysis and environmental impact assessment for self-sufficient non-interconnected islands: The case of Nisyros island

The European continent is surrounded by islands, which even though geographically and socially diverse, share common energy burdens regarding heavy fossil fuels reliance. More specifically, the non-interconnected islands (NII) encounter unique challenges in the decarbonization processes, rendering them particularly vulnerable to the impacts of such transitions. Numerous studies have been conducted to address such emerging issues. However, a research gap exists, as most of the proposed RES-related grid interventions neglect actual historical data in favor of a more theoretical, but possibly misleading, approach. In addition, potential grid stability concerns arising from high levels of RES penetration remain unaddressed. To this end, the objective of the present study focuses on addressing mainly electrical grid stability and resiliency considerations (e.g. imbalances, frequency fluctuations, voltage unbalance rate, for the case of energy islands, as in the case of the NII Greek island of Nisyros). Two sustainable scenarios including novel technologies (e.g. flywheel instead of conventional BESS, a hybrid transformer, vehicle-to-grid chargers) are examined from an energetic and environmental perspective, for short- (2030) and mid-term (2050) implementation horizons, reaching electrical and energy self-sufficiency targets up to 50% and 95%, respectively. For the energy analysis, capacity-investment optimization problems, power flow simulations and specialized transient simulations were conducted, while for the environmental impact assessment a novel in-house developed tool was utilized. As a result, the proposed interventions can result in significant fossil fuel cost savings of about 88%, reduced CO2 emissions up to 38% and overall remarkable financial and environmental benefits. In conclusion, this study demonstrates that a NII can realistically abolish thermal energy to a bare minimum and enhance its self-sufficiency by harnessing local renewable energy potential, while at the same time ensuring grid stability.

Determination of Critical Dimensions of Microchannels to Ensure the Electrokinetic Biomolecule Preconcentration: Analytical and Numerical Studies.

Preconcentration of biomolecules based on ion concentration polarization (ICP) has been splendidly applied to various biomedical and chemical processes. However, in many circumstances, biomolecule preconcentration could not occur due to the lack of full studies on the preconcentration mechanism, especially on the effect of microchannel dimensions. In this work, we provide analytical studies on the critical dimensions (minimum and maximum) of microchannels for the preconcentration of biomolecules. These formulas are verified with the numerical results by fully solving the coupled governing equations: Poisson-Nernst-Planck and Navier-Stokes experiments with appropriate boundary conditions and assumptions. In addition, we examine the impact of operational parameters, such as electric potentials and critical external pressures, on the formation of the preconcentration. Moreover, two important results are provided for the first time, including the position of the preconcentrated biomolecule region and the concentration enhancement factor of the biomolecules. These analytical and numerical results are consistent with experimental observations and, therefore, could provide sharp insight into the mechanism of biomolecule preconcentration and give useful guidelines to better design and optimize ICP-based microfluidic preconcentration devices.

V Flow Measurements of Pulsatile Flow in Femoral-Popliteal Bypass Proximal Anastomosis Compared with CFD Simulation

This paper presents the experience of using the V Flow high-frame-rate ultrasound vector imaging method to study the pulsatile velocity fields in the area of the proximal anastomosis for femoral popliteal bypass surgery in vitro and in vivo. A representative (average) anastomosis model and the experimental setup designed for in vitro studies covering forward and reverse flow phases throughout the cycle are described. The results of the measurements are presented for areas with a relatively uniform velocity distribution and for areas with pronounced spatial inhomogeneities due to the jet or recirculating nature of the flow. The results of ultrasonic studies of the velocity field of the three-dimensional pulsatile flow in vitro and in vivo are compared with the data of numerical simulations carried out for the average and personalized models based on the Navier–Stokes equations. Acceptable consistency between the results of experimental and numerical studies is demonstrated.

Numerical and experimental study on cavitation enhancement of ultrasonic coupled abrasive jet polishing

Numerical and experimental study on cavitation enhancement of ultrasonic coupled abrasive jet polishing

Experiments on fire-protected and hot-dip galvanised steel bolted connections

Connections are of high significance in the stability and integrity of steel structures. Connections play a key role in structures exposed to fire because they are supposed to support the entire elements against a variety of loads. In steel beams, a connection is generally implemented to join (at least) two perpendicular members. A thorough understanding of the heat transfer in structural members is a prerequisite to a reliable design. In the case of R30 requirements, a large number of members can be left unprotected if they are hot-dip galvanised. If hot-dip galvanising of a structure is not sufficient to provide required fire resistance, one part of the structure could be hot-dip galvanised while another part to be protected with a reactive fire protection system. When connecting a protected beam to an unprotected hot-dip galvanised beam, information regarding the heat transfer between these beams is required.Additional heating in a connection due to hot dip galvanisation needs to be taken into account when verifying the load-bearing capacity of the component protected by reactive fire protection according to EN 1993-1-2. This study investigates the effect of heat development and transfer in full-scale steel I-beams from a hot-dip galvanised secondary beam to an intumescent-coated main beam through various bolted connections such as fin plates, double angles, and stiffeners with lugs. Fire protection was applied to the main beams, while the secondary beams were hot-dip galvanised. A thorough experimental, numerical and theoretical study was implemented as presented in this paper, the results of which are deemed to provide significant input into improving safety, hence mitigating the risk of steel beams.

Ni-based bimetallic catalysts for hydrogen production via (sorption-enhanced) steam methane reforming

The catalytic performance of a monometallic Ni/Al2O3 and three bimetallic catalysts (Ni3M1/Al2O3, with M = Cu, Fe, and Ge) for the (sorption-enhanced) steam methane reforming reaction was evaluated. Ni3Cu1/Al2O3 was found to be the optimal catalyst in terms of methane conversion, hydrogen yield, and purity. Ge also has a promoting effect on the monometallic Ni catalyst, whereas the addition of Fe negatively influenced its performance. Physico-chemical characterization of the materials indicated the formation of alloys upon activation of the materials with hydrogen. The addition of Cu increased the surface area and metal dispersion, and improved the overall morphology of the catalyst. The experimental observations were also supported by a numerical study combining Density Functional Theory-based calculations and Microkinetic modelling of the SMR process. Ni3Cu1 and Ni3Ge1 were calculated to have a similar level of catalytic activity as Ni, whereas Ni3Fe1 was unsuitable for the reaction. The SMR reaction was further improved by adding calcium oxide as the CO2 sorbent, which increased methane conversion, CO selectivity, hydrogen yield, and hydrogen purity. The highest methane conversion of 97 % was achieved by Ni/Al2O3 and Ni3Cu1/Al2O3 at 700 °C.