Open Profile Research Articles

Effect of creep-fatigue loading condition on crack tip fields of grade 91 steel at crack initiation and growth

In this paper, the effect of creep-fatigue loading condition on crack tip deformation and stress fields of Grade 91 steel at 600 °C at crack initiation and growth is studied. By using finite element debond analysis method, creep-fatigue crack growth tests using C(T) specimens under various load ratios and hold times are simulated, and the effect of creep-fatigue load ratio and hold time on the crack opening profile, equivalent stress, crack-opening stress and triaxiality at crack initiation and growth is presented. It is found that the crack tip deformation and stress fields under tension–compression creep-fatigue loading are overall different from those under tension-tension creep-fatigue and pure creep loading, due to re-sharpening of the crack tip.

Exploring the enhanced performance of Sb2S3/doped‐carbon composites as potential anode materials for sodium‐ion batteries: A density functional theory approach

AbstractThe improvement of performance in sodium ion batteries is a subject of intense research. In this work, a first principle calculations study at the density functional level on the adsorption process of Na adatoms into Sb2S3/carbon (Sb2S3/CM) and Sb2S3/heteroatom doped‐carbon (Sb2S3/S‐CM, Sb2S3/Sb‐CM) is presented. The sulfur and antimony doped‐carbon substrates enhance the adsorption energies, charge transfer, specific capacities and the diffusion properties of Na adatoms into the Sb2S3/S‐CM and Sb2S3/Sb‐CM composite systems. The Na storage capacity trend and the open circuit voltage profile follows the trend observed in previous experimental results. This work explores perspectives through tailoring 2D carbon anodes with doping heteroatoms in the presence of adsorbed Sb2S3 for an outstanding storage capacity and cycling stability architecture.

Agro-Morpho-Pedological Evaluation of Soils under Hevea in Marginal Zones: The Case of the Departments of Man and Toumodi

Among the ecological conditions of the environment allowing profitable rubber cultivation, rainfall and the physico-chemical characteristics of the soil are the most important. With this in mind, a study on the adaptability of rubber trees to new agro-morphopedological zones was conducted in the departments of Man and Toumodi. The methodology used to achieve this objective is the realization of pedological pits coupled with physico-chemical laboratory analyses. The open soil profiles reveal that the soils belong mainly to the Ferralsols class with distinctive characteristics, except for those of Kimoukro which belong to the Cambisols class. The Toumodi soils, with a sandy-clay texture (15-35% clay), have a high content of coarse sand (over 40%) and good internal drainage in the surface horizons. They are less dense (≤ 1 g/cm3), with a high coarse element load (40%). These soils are chemically rich with a slightly acidic pH. For the Man soils, the sandy-clay texture, with more than 50% clay, from surface to depth, was the most representative fraction. The coarse element load (≥ 50%) and bulk density (≥ 1.5 g/cm3) were more important. These strongly acidic soils are rich in nitrogen and carbon. Exchangeable bases and CEC are important, mainly, in the upper horizons. In addition, the soil profiles observed in these two departments revealed two major pedogenetic processes: reworking and rejuvenation. At the agronomic level, vegetative growth and rubber production of rubber trees were better in Man than in Toumodi. The physico-chemical characteristics of the soils indicate that the departments of Man and Toumodi are favorable for rubber cultivation, although the soils in Man department are more suitable for cultivation.

Complete Mesoscopic Parameterization of Single LNA Modifications in DNA Applied to Oncogene Probe Design.

The use of mesoscopic models to describe the thermodynamic properties of locked nucleic acid (LNA)-modified nucleotides can provide useful insights into their properties, such as hydrogen-bonding and stacking interactions. In addition, the mesoscopic parameters can be used to optimize LNA insertion in probes, to achieve accurate melting temperature predictions, and to obtain duplex opening profiles at the base-pair level. Here, we applied this type of model to parameterize a large set of melting temperatures for LNA-modified sequences, from published sources, covering all possible nearest-neighbor configurations. We have found a very large increase in Morse potentials, which indicates very strong hydrogen bonding as the main cause of improved LNA thermodynamic stability. LNA-modified adenine-thymine (AT) was found to have similar hydrogen bonding to unmodified cytosine-guanine (CG) base pairs, while for LNA CG, we found exceptionally large hydrogen bonding. In contrast, stacking interactions, which were thought to be behind the stability of LNA, were similar to unmodified DNA in most cases. We applied the new LNA parameters to the design of BRAF, KRAS, and EGFR oncogene variants by testing all possible LNA modifications. Selected sequences were then synthesized and had their hybridization temperatures measured, achieving a prediction accuracy within 1 °C. We performed a detailed base-pair opening analysis to discuss specific aspects of these probe hybridizations that may be relevant for probe design.

Energetics of cracks and defects in soft materials: The role of surface stress

In classical fracture theory, the resistance to fracture is governed by the fracture toughness Gc, which is defined as the energy required to create new crack surfaces. To propagate a crack, the energy released to the crack tip (i.e. the energy release rate J) must overcome the fracture toughness Gc. Previous studies have demonstrated that surface stress can significantly modify the crack opening displacement and the stress field in soft solids and hence alter the energy release rate J, assuming small deformation. In this paper, we present a theoretical work on how surface stress affects fracture of soft solids under large deformation. We provide an expression of a modified J-integral for the energy release rate that accounts for surface stress. The expression is verified using large-deformation finite element analysis (FEA) with surface stress elements. Our results show that when the elastocapillary length, defined as the ratio of surface stress σ to the Young’s modulus of the solid E, is comparable to the relevant material size, surface stress noticeably blunts the crack opening profile and reduces the energy release rate.

Chromatin Landscapes of Human Lung Cells Predict Potentially Functional Chronic Obstructive Pulmonary Disease Genome-Wide Association Study Variants

Genome-wide association studies (GWASs) have identified dozens of loci associated with risk of chronic obstructive pulmonary disease (COPD). However, identifying the causal variants and their functional role in the appropriate cell type remains a major challenge. We aimed to identify putative causal variants in 82 GWAS loci associated with COPD susceptibility and predict the regulatory impact of these variants in lung-cell types. We used an integrated approach featuring statistical fine mapping, open chromatin profiling, and machine learning to identify functional variants. We generated chromatin accessibility data using the Assay for Transposase-Accessible Chromatin with High-Throughput Sequencing (ATAC-seq) for human primary lung-cell types implicated in COPD pathobiology. We then evaluated the enrichment of COPD risk variants in lung-specific open chromatin regions and generated cell type-specific regulatory predictions for >6,500 variants corresponding to 82 COPD GWAS loci. Integration of the fine-mapped variants with lung open chromatin regions helped prioritize 22 variants in putative regulatory elements with potential functional effects. Comparison with functional predictions from 222 Encyclopedia of DNA Elements (ENCODE) cell samples revealed cell type-specific regulatory effects of COPD variants in the lung epithelium, endothelium, and immune cells. We identified potential causal variants for COPD risk by integrating fine mapping in GWAS loci with cell-specific regulatory profiling, highlighting the importance of leveraging the chromatin status in relevant cell types to predict the molecular effects of risk variants in lung disease.

Lateral-torsional buckling of partially protected steel I-beams exposed to fire

This paper proposes a new model for thin-walled open profiles able to predict bending-torsion buckling of thermally restrained steel I beams with bi- and mono-symmetric cross-sections. Refined nonlinear kinematics accounts for the shifts of the centroid and shear centre generated by the thermal gradient. The eigenvalue problem derived from geometrically nonlinear balance equations is solved via power series and Newton-Raphson technique. Several examples are presented; the results are compared with those provided by Abaqus simulation and the literature.

On Natural Oscillations of a Thin Elastic Wavy Shell of an Open Profile

The article touches upon the problem of natural oscillations of a thin elastic wavy shell of an open profile. The proposed method for determining the numerical values of the lowest frequencies and the corresponding forms of natural oscillations of shells of a complicated shape is based on the Rayleigh-Ritz energy method.
 The results of numerical calculation of this thin wavy shell with a hinge-fixed attachment along the lower contour along the generatrix are presented.

The selection of the main axis and the forming plane in automatic profiling and stamping lines

The article defines the main axis and the profiling plane in automatic profiling and stamping lines. Specific recommendations are given for choosing the position of the main axis and the profiling plane, depending on the configuration of the manufactured parts of the roll-formed section. Under the general name of profiling in the practice of stamping works, it is meant to obtain rigid and light profiles of large length and various configurations from sheet blanks. Profiling is carried out in four ways: in dies on crank presses, in dies on special bending presses, on universal bending machines (edging machines), on profiling roller machines. The first method, profiling on crank presses, is used for complex semi-closed and open profiles of relatively small length, if there are no special bending presses or profiling machines. The second method, profiling on special bending presses, is used for open and semiclosed profiles up to 5 mm long. The advantage of such presses is the possibility of using simple, and therefore cheap, tools in the manufacture. The third method, profiling on universal bending machines (edging machines), is used for bending parts (profiles of a simple shape in straight lines with different coupling radii determined by the radius of the machine ruler, for which the latter has a set of rulers). Bending machines allow bending materials of small thickness. Low productivity and the need for physical labor costs limit the use of these machines. The fourth method, profiling on roller machines, is used for open, semi-closed and closed profiles. The essence of the profiling process is to gradually change the profile drawing of a flat belt to a given profile when it is moved sequentially through several pairs of shaped rollers arranged sequentially one after the other in the same plane and rotating at the same speed. The article describes in detail the fourth method; the advantages and disadvantages are noted.

New sheet metal forming process for springback reduction by continuous stress superposition

The use of ultra-high-strength steels (UHSS) enables a lightweight and resistant design of sheet metal parts in modern car body structures. In terms of manufacturing such dedicated materials, intense springback phenomena reduce the process stability and dimensional quality. In this context, new developments in springback compensation show promising results when superimposing stresses. Therefore, this paper deals with a new approach, which modifies conventional deep drawing of open profiles by substituting the blankholder by L-shaped sliders. This allows an additional application of horizontally acting forces along the edge of the flange and leads to advantageous free buckling and rolling of the material onto lateral punch surfaces. A numerical feasibility study of this new forming method was performed in this work, showing that compressive stresses and alternate bending through buckling in fact does reduce the amount of springback remarkably compared to conventional deep drawing.

Beam energy metrics for the acceptance and quality assurance of Halcyon linear accelerator.

PurposeEstablish and compare two metrics for monitoring beam energy changes in the Halcyon platform and evaluate the accuracy of these metrics across multiple Halcyon linacs.MethodThe first energy metric is derived from the diagonal normalized flatness (FDN), which is defined as the ratio of the average measurements at a fixed off‐axis equal distance along the open profiles in two diagonals to the measurement at the central axis with an ionization chamber array (ICA). The second energy metric comes from the area ratio (AR) of the quad wedge (QW) profiles measured with the QW on the top of the ICA. Beam energy is changed by adjusting the magnetron current in a non‐clinical Halcyon. With D10cm measured in water at each beam energy, the relationships between FDN or AR energy metrics to D10cm in water is established with linear regression across six energy settings. The coefficients from these regressions allow D10cm(FDN) calculation from FDN using open profiles and D10cm(QW) calculation from AR using QW profiles.ResultsFive Halcyon linacs from five institutions were used to evaluate the accuracy of the D10cm(FDN) and the D10cm(QW) energy metrics by comparing to the D10cm values computed from the treatment planning system (TPS) and D10cm measured in water. For the five linacs, the D10cm(FDN) reported by the ICA based on FDN from open profiles agreed with that calculated by TPS within –0.29 ± 0.23% and 0.61% maximum discrepancy; the D10cm(QW) reported by the QW profiles agreed with that calculated by TPS within –0.82 ± 1.27% and –2.43% maximum discrepancy.ConclusionThe FDN‐based energy metric D10cm(FDN) can be used for acceptance testing of beam energy, and also for the verification of energy in periodic quality assurance (QA) processes.

Some aspects of consideration of initial imperfections in the calculations of stability of thin-walled elements of open profile

Performed analysis of the initial geometric imperfections influence on the stability of the open C-shaped bars. Test tasks were solved in MSC Nastran, which is based on the finite element method. Imperfections are given in different formulations: the general stability loss of an ideal bar, of wavy bulging of walls and shelves, of deplanation of a bar. To model imperfections, has been developed a program which for the formation of new coordinates of the nodes of the "deformed" model, the components of a vector similar to the form of stability loss are added to the corresponding coordinates of the middle surface of the bar. In this way, you can set initial imperfections in the forms of stability loss of the bar with different amplitude. Researches made with different values of the imperfection amplitude and eccentricity of applied efforts. All tasks are performed in linear and nonlinear staging. The conclusion is made regarding the influence of initial imperfections form and imperfection amplitude on the critical force in nonlinear calculations. It was found that the most affected are imperfections, which are given in the form of total loss of stability. It was revealed the influence of the imperfection amplitude on the magnitude of the critical force for such imperfections. The influence of imperfections amplitude given in the form of wavy bulging walls and in the form of deplanations is not affected on the value of the critical force.

Формирование образовательной инфраструктуры в целях обеспечения занятости на предпринимательском рынке

Presented is the mechanism of formation an educational-communication digital-interactive regional infrastructure for supporting the labor market and promoting employment. The main task of the mechanism is to form one of the new elements of educational infrastructure that meets population’s needs in education and employment, by introduction and development information technologies, scientific models, and organization on-line interaction with the potential participants in the entrepreneurial market. The mechanism had been created by the authors can function taking into account the existing state programs, containing elements of digitalization, strategies for the development of entrepreneurship and social support for population. On the one hand the main advantage of the proposed mechanism will allow to build a new element of the educational infrastructure using the digital environment, and on the other hand it will help to form a labor market for qualified employees, who will provide a constant supply of the modern specialists to the entrepreneurial market. This goal is possible to achieve by the implementation of such models as the model of the ideal employee, the ideal job and the ideal place of education. Modeling of socio-economic information will help to identify the needs of employers for qualified personnel, form proposals for the entrepreneurial market development, open new training profiles, and predict the demand of future professionals in the interactive labor market. The authors conducted a pilot survey for mechanism evaluation that confirmed future applicants’ goal is to get higher education with the using of information technologies.

Finite Element Analysis of Stretch Forming of an Open Profile Made of Ultra-High Strength Martensitic MS1500 Steel

Stretch forming process is primarily used for generating curved structures from sheet metals such as car body panels or aircraft fuselage panels. Although there are large number of studies about stretch forming, these investigations focus mainly on flat sheet metals. However, various parts especially in the automotive industry, such as passenger car fenders are first preformed to a profile and afterwards stretch formed to generate desired final geometry. Moreover, as a consequence of weight reduction activities, these fender parts are usually made of ultra-high strength steels (UHSS) in the last two years. In the current study, stretch forming characteristics of an open profile made of martensitic UHSS (MS1500) are investigated using finite elements method (FEM). Used geometry was an asymmetrical hat profile which was preformed using roll forming prior to stretch forming. Mechanical properties of the material used is characterized using tensile test and modeled using Swift isotropic strain hardening rule. Strain and stress distribution along the bend section, geometry and springback in the final part as well as forming force have been investigated using finite element (FE) simulations. A twist has been observed in the final product along its longitudinal axis. To validate the FE results, experiments have been conducted. Twist problem is also detected in the manufactured samples. The amount of springback in produced part was similar to the experiments. It is found that FE simulations can model stretch forming process of open profiles accurately.

ORCID-linked labeled data for evaluating author name disambiguation at scale

How can we evaluate the performance of a disambiguation method implemented on big bibliographic data? This study suggests that the open researcher profile system, ORCID, can be used as an authority source to label name instances at scale. This study demonstrates the potential by evaluating the disambiguation performances of Author-ity2009 (which algorithmically disambiguates author names in MEDLINE) using 3 million name instances that are automatically labeled through linkage to 5 million ORCID researcher profiles. Results show that although ORCID-linked labeled data do not effectively represent the population of name instances in Author-ity2009, they do effectively capture the ‘high precision over high recall’ performances of Author-ity2009. In addition, ORCID-linked labeled data can provide nuanced details about the Author-ity2009’s performance when name instances are evaluated within and across ethnicity categories. As ORCID continues to be expanded to include more researchers, labeled data via ORCID-linkage can be improved in representing the population of a whole disambiguated data and updated on a regular basis. This can benefit author name disambiguation researchers and practitioners who need large-scale labeled data but lack resources for manual labeling or access to other authority sources for linkage-based labeling. The ORCID-linked labeled data for Author-ity2009 are publicly available for validation and reuse.

Initial Geometric Imperfections: A Robust, Closed-Section Cold-Formed Box Profile Application Subject to Local Buckling

Initial geometric imperfections are important for simulating local buckling in numerical models. References are found in the technical literature regarding open-section cold formed profiles. This work presents new procedures applied to a robust and closed-section cold formed profile subject to local buckling, and the use of procedures described in the technical literature already successfully used for open section profiles. The difference of this work in relation to the research already carried out is in the type of profile studied, in the mode of failure of the same and in the form of determination of the initial imperfections. The object of study of this work is a closed-section cold formed box profile with a short length when compared with its cross section and with local buckling failure mode. The strategies used in the present work to consider the initial geometric imperfections were to perform the linear stability analysis using the finite element method to obtain the local buckling mode that represents the deformed box profile geometry, to apply a multiplication factor in the displacements, replace the new geometry node coordinates for all profile nodes to induce the local buckling deformation mode, with model validation through experimental testing and the Effective Width Method (MLE) (ABNT NBR 14762 [1]). Finally, using the results of the collapse load of the experimental trial as a basis, it was possible to compare the results obtained by MLE and MEF. Thus, the presentation of this work used a methodology that describes the local buckling behavior and verified the precepts of the existing norms on the subject, combining theoretical and experimental methods, as they bring a better understanding of the structural problem in question.

Chromatin Accessibility of Human Mitral Valves and Functional Assessment of MVP Risk Loci.

Mitral valve prolapse (MVP) is a common valvopathy that leads to mitral insufficiency, heart failure, and sudden death. Functional genomic studies in mitral valves are needed to better characterize MVP-associated variants and target genes. To establish the chromatin accessibility profiles and assess functionality of variants and narrow down target genes at MVP loci. We mapped the open chromatin regions in nuclei from 11 human pathogenic and 7 nonpathogenic mitral valves by an assay for transposase-accessible chromatin with high-throughput sequencing. Open chromatin peaks were globally similar between pathogenic and nonpathogenic valves. Compared with the heart tissue and cardiac fibroblasts, we found that MV-specific assay for transposase-accessible chromatin with high-throughput sequencing peaks are enriched near genes involved in extracellular matrix organization, chondrocyte differentiation, and connective tissue development. One of the most enriched motifs in MV-specific open chromatin peaks was for the nuclear factor of activated T cells family of TFs (transcription factors) involved in valve endocardial and interstitial cell formation. We also found that MVP-associated variants were significantly enriched (P<0.05) in mitral valve open chromatin peaks. Integration of the assay for transposase-accessible chromatin with high-throughput sequencing data with risk loci, extensive functional annotation, and gene reporter assay suggest plausible causal variants for rs2641440 at the SMG6/SRR locus and rs6723013 at the IGFBP2/IGFBP5/TNS1 locus. CRISPR-Cas9 deletion of the sequence including rs6723013 in human fibroblasts correlated with increased expression only for TNS1. Circular chromatin conformation capture followed by high-throughput sequencing experiments provided evidence for several target genes, including SRR, HIC1, and DPH1 at the SMG6/SRR locus and further supported TNS1 as the most likely target gene on chromosome 2. Here, we describe unprecedented genome-wide open chromatin profiles from human pathogenic and nonpathogenic MVs and report specific gene regulation profiles, compared with the heart. We also report in vitro functional evidence for potential causal variants and target genes at MVP risk loci involving established and new biological mechanisms. Graphic Abstract: A graphic abstract is available for this article.

OTX2 regulates CFTR expression during endoderm differentiation and occupies 3' cis-regulatory elements.

Cell-specific and developmental mechanisms contribute to expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene; however, its developmental regulation is poorly understood. Here we use human induced pluripotent stem cells differentiated into pseudostratified airway epithelial cells to study these mechanisms. Changes in gene expression and open chromatin profiles were investigated by RNA-seq and ATAC-seq, and revealed that alterations in CFTR expression are associated with differences in stage-specific open chromatin. Additionally, two novel open chromatin regions, at +19.6 kb and +22.6 kb 3' to the CFTR translational stop signal, were observed in definitive endoderm (DE) cells, prior to an increase in CFTR expression in anterior foregut endoderm (AFE) cells. Chromatin studies in DE and AFE cells revealed enrichment of active enhancer marks and occupancy of OTX2 at these sites in DE cells. Loss of OTX2 in DE cells alters histone modifications across the CFTR locus and results in a 2.5-fold to 5-fold increase in CFTR expression. However, deletion of the +22.6 kb site alone does not affect CFTR expression in DE or AFE cells. These results suggest that a network of interacting cis-regulatory elements recruit OTX2 to the locus to impact CFTR expression during early endoderm differentiation.

Single Dose Study Assessing the Pharmacokinetic and Metabolic Profile of Alverine Citrate in Healthy Volunteers.

Alverine citrate is a spasmolytic commonly prescribed in conditions such as irritable bowel syndrome, painful diverticular disease of the colon, and primary dysmenorrhea. While clinical efficacy data on alverine alone or in combination with simethicone is freely available, surprisingly little information regarding the pharmacokinetics and metabolism of alverine can be found in literature. The first HPLC-MS/MS analytical protocol for determination of alverine parent, 4-hydroxy alverine, N-desethyl alverine and 4-hydroxy alverine glucuronide in human plasma was developed and validated. The two validated methods were used for analyzing plasma samples collected during an open label, non-comparative, single dose, one-period, one-treatment, pharmacokinetic and metabolic profile study of Spasmonal® Forte 120 mg hard capsule, conducted in 12 fasting healthy male and female volunteers of Caucasian descent. The study confirmed previous suspicions that parent alverine is subject to high pharmacokinetic variability and also revealed that the metabolic process most susceptible to outlying performance in Caucasians is hydroxylation to the active metabolite 4-hydroxy alverine. Another interesting observation made is that alverine parent accounts for only 3%, whereas total 4-hydroxy alverine (free and conjugated) accounts for 94% of alverine-related moieties in circulation (based on comparisons of total exposure).

Numerical analysis of hydraulic fracturing processes for multi-layered fractured reservoirs

Accurate simulation of Hydraulic fracturing in naturally fractured reservoirs significantly impacts the prediction of the fracturing treatment process. The objective of this study is to numerically analyze the hydraulic fracturing processes in a multi-layered fractured reservoir. Therefore, mechanical mass balance equations for fluids, solids, and their interactions with produced fractures were simultaneously solved in ABAQUS software based on the finite element method. According to the result of this study, by increasing the layers’ depth from layer A to Layer C, the fluid leakage rate has been increased due to the more volumes of fluid loss in higher depths. By plotting linear equations, it can be concluded that linear equations can be derived approximately for other layers without modeling all the layers by deriving one linear equation for one layer. Moreover, the maximum opening pressure for fracturing for Layer A–C is 60, 73, and 78 Mpa, respectively. It is concluded that there is higher pressure needed to opening or creating the new fractures in the formation at higher depths. On the other hand, by deriving polynomial equations for each layer, it is concluded that there is an approximate relationship for each layer, which can be expanded for other layers Moreover, by this approach, it is possible to predict the pressure difference behavior through the fracture propagation length without any unnecessary field application. Consequently, the fracture opening profile is approximately 9.5 for the deepest layer as it has the best junction with the fracture tips and the middle points of the wellbore.