bluuebunny/crossref_metadata_2025 huggingface dataset:
THE AUTHORITY OF THE DISTRICT HEAD IN TO MANAGE REGIONAL OWNED ENTERPRISES
Authors: Pradhana Ryan Surya
Published: April 2021

Law Number 23 of 2014 concerning Regional Government divides Regional-Owned Enterprises into Regional Public Companies and Regional Companies. The Regional Government Law divides government affairs into three classifications, namely absolute government affairs, concurrent government affairs, and general government affairs. Furthermore, government authority is the right and obligation of the government in carrying out government actions or actions as regulated in Article 1 point 6 jo. Article 17 through Article 19 jo. Article 1 point 8 of the Government Administration Law. Regional government authority is the implementation of government affairs as regulated in Article 1 point 5 of the Regional Government Law, which states that government affairs are governmental powers which are the authority of the President whose implementation is carried out by state ministries and administrators of Regional Governments to protect, serve, empower and prosper the community, among others through the establishment of Regional owned enterprises. Regional-owned enterprises are established through regional regulations based on regional needs and business field feasibility. Regional needs are assessed through studies covering aspects of public services and community needs. Meanwhile, the feasibility of the business sector of Regional Owned Enterprises is studied through analysis of economic feasibility, market and marketing analysis, financial feasibility analysis, and analysis of other aspects. Analysis of other aspects contains aspects of laws and regulations, availability of technology, and availability of human resources.
PERBANDINGAN KEMAMPUAN AFEKTIF SISWA KELAS XI SMAN 1 SULIKI ANTARA PENGGUNAAN HANDOUT DILENGKAPI PETA KONSEP DAN PETA PIKIRAN DALAM MODEL PEMBELAJARAN KOOPERATIF TIPE STUDENT TEAMS ACHIEVEMENT DIVISION (STAD)
Authors: Asti Asti febrina
Published: April 2021

Based on the observations made at SMAN 1 Suliki on August 20, 2015, the reality is that in the learning process, attention and negative student activities in the classroom are still many such as, drowsiness during learning, and lack of interaction between students and teachers during the teaching and learning process. Students also lack interact with each other, in conducting group discussions. Highly capable students are still unable to work with low-skilled students. The learning resources used by teachers in the field of study are still package books, so that makes students only control package books in learning. The other learning resources provided in schools are LKS, but the delivery of materials in this LKS is still not colored. Every time they start learning, students still forget to bring a package book. Therefore, learning ppenelitian becomes less effective because of the lack of teaching materials used by teachers and learning methods that are still not appropriately used by teachers. Then the creation of mind map handouts and concept maps with STAD learning models is the solution.This type of research is quasi experimental research. The sampling technique used is purposive sampling technique by assigning experiment class I and class II experiment in drawn. So that obtained the selected sample class XI IPA5 and XI IPA6. The research instrument used is the instrument used for the assessment of the affective aspects of students is the assessment sheet of affective aspects. This assessment sheet aims to assess students' attitudes and behaviors during the learning process. The assessment sheet contains the observed aspects of students' attitudes and behaviors. Based on the results of the research conducted showed that in the affective realm by using handouts of mind maps and concept maps in cooperative learning models STAD is 93.16 (class I experiment) category is very good, and 72.25 (experiment II) with good category. In the first class of experiments have better affective competence than the second class of experiments.
PERSEPSI PESERTA DIDIK TERHADAP 10 KETERAMPILAN MENGAJAR GURU BIOLOGI PRAKTEK LAPANGAN (PL) DI SMAN 1 BUKITTINGGI
Authors: Rahmi Ennike Gusti
Published: April 2021

The purpose of this study was to find out students' perception of the teaching skills of field practice biology teachers (PL) at SMAN 1 Bukittinggi. This research is descriptive research. The sampling technique used is Random Sampling, where each class is sampled for 20% of the total number of students. Thus from the population of mipa students in grade X and XI  SMAN 1 Bukittinggi in the 2018/2019 school year amounted to 273 students spread across 8 locally, sampled by 20% of 56 students. The data obtained is processed using percentage technique (%). Based on the analysis of data obtained from the results of the study, it is known that students' perception of the teaching skills of field practice biology teachers in SMAN 1 as a whole is good with a percentage of 82.25%. While reviewed from each sub-variable described as follows: 1) Skills of opening and closing learning with a percentage of 85.14%, good category; 2) Skills managing classes with a percentage of 77,68%, category is quite good; 3) Reinforcement skills with a percentage of 74,25%, the category is quite good; 4) Skills guiding small group discussions with a percentage of 79,51%, a pretty good category; 5) Questioning skills with a percentage of 82.71%, good category; 6) Skill explaining with percentage 81.28, good category; 7) Skills held variasai with a percentage of 79.21%, the category is quite good; 8) Teaching skills of small groups and individuals with a percentage of 78,20%, the category is quite good; 9) Skills to develop and use learning media with a percentage of 82.42%, good category; 10) Esq developing skills with a percentage of 78.42%, the category is quite good.
HUBUNGAN KEHARMONISAN KELUARGA DENGAN KONSEP DIRI SISWA
Authors: Nurhasnah
Published: April 2021

This research was motivated by various problems experienced by students to form and develop self-concepts. Family harmony and socioeconomic status are factors that are thought to influence the development of students' concepts. This study aims to describe: (1) family harmony, (2) the self-concept, (3) relationship of family harmony with self concept. This research uses quantitative methods of descriptive type correlational. The research population is 332 students of SMAN 1 Rao Pasaman. A sample of 182 students, selected with Proportional Stratified Random Sampling. The instrument used is model likert scale. The study findings showed that: (1) student family harmony is in a harmonious category with a percentage of 77.55% of the ideal, (2) the self-concept of the student's is in a positive category with a percentage of 68.88% of the ideal, (3) there is a positive and significant relationship between family harmony and self-concept, the contribution of family harmony to the self -concept is 19%. This means that family harmony variables can be used as predictors to predict self-concept.
Experimental Investigation of Damage and Failure Mechanisms of Polymer-Metal Joints assembled by Self-Piercing Riveting
Authors: Amro Elias , Kouadri-Henni Afia
Published: April 2021

The increased use of polymer-based material in the manufacturing of vehicles structures makes critical the management of multi-material interfaces, and hence the issue of polymer-metal joining. It has been demonstrated in the literature that for large-scale manufacturing, self-piercing riveting (SPR) represents a reliable alternative technique to conventional resistance spot welding (RSW). However, the riveting operation induces, by nature, damages to the joint composite layer due to the steel rivet crossing it. In this study, the damage of the SMC thermoset material during SPR process has been experimentally investigated. Moreover, the influence of the riveting velocity as a major SPR process parameter on the composite layer damage has been identified. Eventually, the failure mechanisms of the polymer-metal joint resulting from failure under lap-shear and pure tension loadings were studied with the support of the numerical simulation tool.
Towards numerical prediction of flow-induced fiber displacements during wet compression molding (WCM)
Authors: Poppe Christian , Albrecht Fabian , Krauß Constantin , Kärger Luise
Published: April 2021

Wet compression molding (WCM) provides large-scale production potential for continuous fiber-reinforced structural components due to simultaneous infiltration and draping during molding. Due to thickness-dominated infiltration of the laminate, comparatively low cavity pressures are sufficient – a considerable economic advantage. Experimental and numerical investigations prove strong mutual dependencies between the physical mechanisms, especially between resin flow (mold filling) and textile forming (draping), similar to other liquid molding techniques (LCM). Although these dependencies provide significant benefits such as improved contact, draping and infiltration capabilities, they may also lead to adverse effects such as flow-induced fiber displacement. To support WCM process and part development, process simulation requires a fully coupled approach including the capability to predict critical process effects. This work aims to demonstrate the suitability of a macroscopic, fully coupled, three-dimensional process simulation approach, to predict the process behavior during WCM, including flow-induced fiber displacements. The developed fluid model is superimposed to a suitable 3D forming model, which accounts for the deformation mechanisms including non-linear transverse compaction behavior. A strong Fluid-Structure-Interaction (FSI) enforced by Terzaghi’s law is applied to assess flow-induced fiber displacements during WCM within a porous UD-NCF stack in a homogenized manner. Accordingly, resulting local deformations are considered within the pressure field. All constitutive equations are formulated with respect to fiber deformation under finite strains. Results of a parametric study underline the relevance of contact conditions within the dry and infiltrated stack. The numerically predicted results are benchmarked and verified using both own and available experimental results from literature.
Higher Productivity In Forming High-alloyed Steel By Temperature Insensitive Friction Behavior
Authors: Aha Bernd , Hettich Daniel , Veldhuis Mark , Filzek Jan
Published: April 2021

Like in many other production technologies, a broad process window for metal forming is desired. The goal is always a stable process chain. One of the key aspects for metal forming are stable tribological conditions. Instabilities can be caused by, amongst others, different material batches, change in temperature during the production process, different lubricant amounts and different stroke rates. At the beginning of a production run, the tribological stability suffers from transient temperature effects caused by plastic and frictional work and a viscosity drop of the lubricant. To control the tribology, different strategies are suitable: changing the oil type, the oil amount, the blank holder force or the stroke rate. Within the EU-project ASPECT, control strategies on blank holder forces are developed as well as lubricants with improved stability on their behaviour as a function of temperature. This paper will focus on the latter. In preliminary ball on plate test the friction and wear of lubricant formulations were investigated and compared to a Reference lubricant. Followed by strip drawing and forming tests. Finally, the concept is proven in trials on a demonstrator line, which is close to serial production.
Processability of metal-filament through polymer FDM machine
Authors: Quarto Mariangela , Carminati Mattia , D’Urso Gianluca , Giardini Claudio , Maccarini Giancarlo
Published: April 2021

FDM is one of the simplest and cheapest available additive technologies, mostly limited to polymeric materials. Metal-FDM process may overcome this limit using a metal filament bounded with polymer, which is removed through debinding and sintering treatments. Producing metal components using an economic machine would make it possible to produce non-critical components with complex geometry at an industrial level and at low-cost. This work aims to investigate whether a low-cost commercial 3D printer may be able to print a metal filament and what are the achievable density and the shrinkage on the final part. An experimental campaign (24 factorial plan) was performed, considering as variable factors the nozzle temperature, the infill pattern, the print speed and the layer thickness. Statistical tools as the boxplot for determining outliers and the analysis of variance (ANOVA) were used to evaluate the results, identifying which process parameters ad their interactions affect the selected indicators (density and shrinkage). The results show that the conversion of a low-cost FDM machine from polymer to metal filament is possible, generating repeatable and stable results. The process is faster and less expensive than the existing powder-bed-fusion based metal AM technology. The best combination of printing parameters was identified considering as target point the density of the “traditional” AISI 316L steel. Different behaviors in terms of shrinkage were identified: trends are stable and very similar for X and Y directions, independently from the printing parameters, while the interaction between temperature and other parameters causes higher variability along the Z-axis.
Element activation method and non-conformal dynamic remeshing strategy to model additive manufacturing
Authors: Laruelle Cédric , Boman Romain , Papeleux Luc , Ponthot Jean-Philippe
Published: April 2021

Modeling of Additive Manufacturing (AM) at the part scale involves non-linear thermo-mechanical simulations. Such a process also imposes a very fine discretization and requires altering the geometry of the models during the simulations to model the addition of matter, which is a computational challenge by itself. The first focus of this work is the addition of an additive manufacturing module in the fully implicit in-house Finite Element code Metafor [1] which is developed at the University of Liège. The implemented method to activate elements and to activate and deactivate boundary conditions during a simulation is adapted from the element deletion algorithm implemented in Metafor in the scope of crack propagation [2]. This algorithm is modified to allow the activation of elements based on a user-specified criterion (e.g. geometrical criterion, thermal criterion, etc.). The second objective of this work is to improve the efficiency of the AM simulations, in particular by using a dynamic remeshing strategy to reduce the computational cost of the simulations. This remeshing is done using non-conformal meshes, where hanging nodes are handled via the use of Lagrange multiplier constraints. The mesh data transfer used after remeshing is based on projection methods involving finite volumes [3]. The presented model is then compared against a 2D numerical simulation of Direct Energy Deposition of a High-Speed Steel thick deposit from the literature [4].
An Innovative Welding Solution For Polymer Films in Packaging: Effect of Process Parameters
Authors: Tannous Queen , Bereaux Yves , Mousseau Pierre , Barasinski Anaïs , Deterre Rémi , Madec Yannick , Fourmaux Clément
Published: April 2021

In this paper, we present an innovative welding process for packaging applications developed by SEALESTER Company. For polymer films, studies have revealed that the welding interface must reach a specific temperature, known as “sealing initiation temperature”, to obtain a sealed joint. In this paper, we will be studying the effect of the process parameters on the evolution of temperature at the welding interface. For this purpose, thermocouples have been placed between the films at different points of the trajectory to measure the temperature evolution. Process parameters and temperature measurements were recorded in each experiment. Results show that the most influential parameters are the temperature and the linear velocity of the tool. Rotational frequency affects the heat distribution on the sealing surface. A minimum pressure must be applied. In conclusion, this new process can produce sealed polymer packages. Future work will consist of studying the quality of obtained seal in addition to optimization and control of the process.
On the Influence of Manufacturing Strategy of 3D-Printed Polymer Substrates on Cold Spray Deposition
Authors: Viscusi Antonio , Astarita Antonello , Borrelli Domenico , Caraviello Antonio , Carrino Luigi , Gatta Roberta Della , Lopresto Valentina , Papa Ilaria , Perna Alessia Serena , Sansone Raffaele , Squillace Antonino
Published: April 2021

PMCs are anisotropic and heterogeneous structures with excellent performances in terms of mechanical strength and stiffness, coupled with reduced weight, widely used in engineering sectors. The use of PMCs can be further extended by improving their surface properties such as electrical conductivity, erosion, radiation and lightning protection. In this context, the surface metallization seems to be best solution. In particular, the cold spray (CS) technique candidates as a potential method for the manufacturing of a metal coating on PMCs’ surface. However, the design and the manufacturing methods of PMCs can play a crucial role for an effective metallization through CS. The additive manufacturing technologies for composite materials can be used to manufacture customized reinforced polymer-based panels, like PMCs; the most common method for printing them is the Fused Filament Fabrication (FFF) technique which relies on the thermal extrusion of a thermoplastic feedstock from a mobile heated nozzle. Therefore, this research activity aims to manufacture customized PMCs panels by using FFF technology for the substrate and the cold spray technique for the metallization in order to study the influence of the substrate manufacturing strategy on CS deposition process. For this purpose, three kind of 3D-printed PMCs were manufactured through the FFF technology by varying the percentage fill of the Onyx polymeric matrix and aluminum powders were sprayed on the substrates with a low-pressure cold spray (LPCS) system; both FFF and CS process parameters were varied to study the process in its wholeness. Microscope analyses were carried out to analyze the influence of the manufacturing strategy on the coating quality.
Numerical assessment of large hexagonal seamless steel tube extrusion feasibility
Authors: Habans Dylan , Olier Patrick , Sornin Denis , Montmitonnet Pierre , Mocellin Katia
Published: April 2021

The study assesses feasibility of hot extrusion of a large seamless hexagonal 9%Cr-1%Mo steel tube. The manufacturing chain starts from a pierced cylindrical billet, hot extruded and to be further cold drawn in several passes. Preliminary industrial tests have shown thickness reduction in extrusion limited by a huge initial force peak (+25 %) reaching the press capacity. To understand this force peak, thermomechanical numerical simulation (ForgeNxt®) of the furnace-press transfer and extrusion stages is carried out. Constitutive model at high temperature, high strain and strain rate has been selected from literature. Surface properties, namely Heat Transfer Coefficient (HTC) and friction coefficient, have been made space- and time-dependent to represent glass lubrication. Numerical results are qualitatively compared to industrial experimental values to evaluate the prediction of the model. It suggests that the difficult start of the glass melting and flow along a cooled die affects the force peak. Practical improvements are suggested on this basis, together with possible refinements of the simulation for more precision and insight into extruded tube quality.
Optimisation of chemical composition of high-strength structural steels for achieving mechanical property requirements
Authors: Babachenko Oleksandr , Kononenko Hanna , Snigura Iryna , Togobytska Nataliya
Published: April 2021

In addition to thermomechanical treatment, one of the main factors affecting the mechanical properties of steel is the chemical composition. The chemical composition may vary for a special high-strength low-alloy steel to meet certain mechanical property requirements. This work presents an approach, based on the method of physical-chemical modelling developed at the Z.I. Nekrasov Iron and Steel Institute of the National Academy of Sciences of Ukraine, to optimise the chemical composition of high-strength structural steels. The principle of this method is to describe the chemical composition of a melt by a complex of integral model parameters of interatomic interaction, characterising the chemical and structural state of the melt. The experimental data were analysed to obtain the regression model for mechanical properties based on the parameters of interatomic interaction. Finally, a multi-criteria optimisation method was applied to obtain an optimal set of microalloying elements which ensure the required mechanical properties.
An approach of modelling of the compaction of flax-carbon hybrid stack preforms
Authors: Vivet Alexandre , Tossou Eric , Gehring Florian , Mareschal Olivier
Published: April 2021

A model, based on the Van Wyk model, is developed to predict the compaction behaviour of stack sequence of dry fabric plies, and is used a set of 3 parameters (stiffness k, pressure sensitivity n and initial fibre ratio Vf0) with P = (k(Vf- Vf))n. The method originality is to construct the behaviour law of a complex stack sequence by the assembly of elementary behaviours. Elementary behaviours are identified using initial experimental compaction tests and are linked to the interaction of a fabric ply with its surrounding environment (another fabric ply or the surface of the compressive mould). This proposed modelling approach have been tested on various carbon, flax and carbon/flax hybrid stack sequence, and seems efficient to predict their compaction behaviour. Its validity is limited to the range of stack sequence of a reduced number of plies. With stack sequence made of numerous fabric plies, some new phenomena must be taken into account. In complement we proposed a method to decompose the compaction behavior curve into three stages (rigid body movement of the fabric plies, nesting of the plies, densification). This method is relevant to compare easily some compaction curves and to evaluate the internal strain state of a stack sequence.
Multivariable regression and gradient boosting algorithms for energy prediction in the radial-axial ring rolling (rarr) process
Authors: Mirandola Irene , Berti Guido A. , Caracciolo Roberto , Lee Seungro , Kim Naksoo , Quagliato Luca
Published: April 2021

Energy prediction and starvation have become an essential part of process planning for the XXI century manufacturing industry due to cost-saving policies and environmental regulations. To this aim, the research presented in this paper details how machine learning-based algorithms can be an effective way to predict and minimize the energy consumptions in the widely spread radial-axial ring rolling (RARR) process. To analyze this bulk metal forming process, 380 numerical simulations have been developed using the commercial SW Simufact Forming 15 and considering three largely utilized materials, the 42CrMo4 steel, the IN 718 superalloy, and the AA6082 aluminum alloy. To create the database for both multi-variable regression and machine learning models, ring outer diameters ranging from 650 mm to 2000 mm and various process conditions including different sets of tool speeds and initial temperatures have been considered. For the case of the multi-variable regression model, to account for all the cross-influences between all the parameters, a second-order function including 26 parameters has been developed, resulting in a reasonable average accuracy (94 %) but also in an impractical huge equation. On the other hand, the machine learning model based on the Gradient Boosting (GB) approach allows obtaining a similar accuracy (96 %) but its compact form allows a more practical utilization and its training can be expanded almost indefinitely, by adding more results from both numerical simulations and experiments. The proposed approach allows to quickly and precisely predict the energy consumption in the RARR process and can be extended to other manufacturing processes.
Influence of specimen geometry and strain rate on elongation in tensile testing of packaging steel
Authors: Knieps Fabian , Köhl Manuel , Merklein Marion
Published: April 2021

Packaging steel is characterized by low thickness (0.1 mm – 0.5 mm) and ferritic microstructure resulting from low carbon contents. In combination with continuous annealing processes and temper rolling, this results in only little elongation observed in tensile tests. However, as in real forming processes much higher deformation occurs, it is important to receive true stress-true strain data up to a highest possible level e.g. to characterize material for finite element analysis. Therefore, tensile tests with three different measuring lengths (80 mm, 50 mm, 20 mm) were conducted for the packaging steel TH415. Likewise, the testing speed was reduced to investigate the possibility to receive more elongation under the condition of a constant stress level. The results revealed a significant increase in elongation when using smaller tensile test geometries. As well, the reduction in testing speed leads to much higher elongation while showing only little strain rate influence. While for the 80 mm geometry and standard speed no homogenous forming condition could be reached due to early failure before Lüders strain, this could be improved by using smaller testing specimens and a lower strain rate. Combining the influence of strain rate and geometry a significant increase of more than ten percentage points in elongation was reached.
Considerations on the Influence of the Tool/Sheet Contact Conditions for Incremental Forming of Niobium Sheets
Authors: Formisano Antonio , Astarita Antonello , Boccarusso Luca , Durante Massimo , Garlasché Marco , Langella Antonio
Published: April 2021

Niobium is a ductile transition metal of growing interest for several technological applications, thanks to its intriguing characteristics, among them high melting point, moderate density, good ductility, high corrosion resistance and superconductivity. By contrast, its use is limited by some weaknesses lied to the mechanical properties, which can undermine the quality of the surfaces worked by metal forming processes. Sheets of pure Niobium can be used for the manufacture of extremely customized components and a flexible process like the incremental sheet forming fits well with this manufacturing philosophy; in fact, this technique does not require complicated tools and/or dedicated equipment and is capable to respond quickly to the market demands. The scope of this paper is to investigate the influence of the tool/sheet contact conditions on different features like the forming loads, the surface quality and the occurrence of failures, when pure Niobium rolled sheets are formed incrementally. To this aim, the simplest variant of incremental sheet forming, namely single point incremental forming, was considered by using a common fixed end forming tool with hemispherical head. The process was carried out under dry and lubricated tool/sheet contact conditions, following the indications from a preliminary campaign of wear tests conducted by a pin-on-disk apparatus. The experimental campaign highlights the strong influence of the tool/sheet contact conditions and the importance of a correct choice of them on the features investigated, in order to limit the forming forces and the risk of failure, as well as to preserve the surface quality of the components made by incremental sheet forming of Niobium.
A Cost-Effective Method for Bulge Prediction in Two Point Incremental Forming
Authors: Shin Jaekwang , Bansal Ankush , Cheng Randy , Taub Alan , Banu Mihaela
Published: April 2021

Accurate prediction of the defects occurring in incrementally formed parts has been gaining attention in recent years. This interest is because accurate predictions can overcome the limitation in the advancement of incremental forming in industrial-scale implementation, which has been held back by the increase in the cost and development time due to trial and error methods. The finite element method has been widely utilized to predict the defects in the formed part, e.g., bulge. However, the computation time of running these models and their mesh-size dependency in predicting the forming defects represent barriers in adopting these models as part of CAD-FEM-CAE platforms. Thus, robust analytical and data-driven algorithms must be developed for a cost-effective design of complex parts. In this paper, a new analytical model is proposed to predict the bulge location and geometry in two point incremental forming of an aerospace aluminum alloy AA7075-O for a 67° truncated cone. First, the algorithm calculates the region of interest based on the part geometry. A novel shape function and weighted summation method are then utilized to calculate the amplitude of the instability produced by material accumulation during forming, leading to a bulge on the unformed portion of the sample. It was found that the geometric profile of the part influences the shape function, which is a function created to incorporate the effects of process parameter and boundary condition. The calculated profile in each direction is finalized into one 3-dimensional profile, compared with the experimental results for validation. The proposed model has proven to predict an accurate bulge profile with 95% accuracy comparing with experiments with less than 5% computational cost of FEM modeling.
Finite element simulation of tool wear in machining of nickel-chromiumbased superalloy
Authors: Abeni Andrea , Cappellini Cristian , Attanasio Aldo
Published: April 2021

The phenomenon of tool wear strongly affects the efficiency of machining and the quality of machined products. The experimental approach to investigate tool wear requires several time consuming tests. Finite Element Methods (FEM) can be utilized to predict tool wear and tool life as function of process parameters and tool geometry. The commercial software for Finite Element Analysis (FEA) are limited by the impossibility to update the geometry of the worn tool. This research utilizes a self-released subroutine in order to modify the tool geometry in DEFORM 3D simulations by considering the volume reduction of the tool. The model was validated with experimental data obtained by drilling tests on Inconel 718 using conventional metal working fluids (MWF). The correct profile of the simulated worn tool was individuated by comparing the prediction of the simulation with the real tool geometry. The FEM simulation allowed to predict how torque changes during the tool life. In a predictive maintenance perspective, the model can be implemented to optimize the tools replacement.
Electromagnetic Embossing of Optical Microstructures with High Aspect Ratios in Thin Aluminum Sheets
Authors: Heidhoff Julian , Beckschwarte Björn , Riemer Oltmann , Schönemann Lars , Herrmann Marius , Schenck Christian , Kuhfuss Bernd
Published: April 2021

Electromagnetic embossing enables the transfer of surface structures from forming dies to metal sheets at high forming speeds. For this purpose, the contactless forming force is provided by means of a magnetic field of a tool coil which interacts with an eddy current in the workpiece. In thin sheets which are completely penetrated by the magnetic field, the resulting Lorentz forces act as body forces that accelerate the workpiece onto the forming die. In addition to the body forces, also high strain rates can support the embossing of thin sheets. This investigation deals with the embossing of pyramidal structures in the submillimeter range and an aspect ratio of about 1 into thin aluminum sheets (3.0255 / Al99,5). In order to quantify the reproduced microstructures, their extent is determined by means of a lateral analysis. From this, the replicated height is derived. Up to now it has been possible to partially reproduce microstructures with a large aspect ratio in thin sheets. In addition, the changing surface roughness of the sheets is taken into account. Before embossing, the sheets exhibit a relatively rough surface with a rolled texture, which is smoothed by the impulse forming with an optical forming die. This study reveals basic approaches for the electromagnetic embossing of optical microstructures.
Macro-meso scale simulations of 3D woven composite reinforcements during the forming process
Authors: Wang Jie , Wang Peng , Hamila Nahiène , Boisse Philippe
Published: April 2021

During the forming stage in the RTM process, deformations and orientations of yarns at the mesoscopic scale are essential to evaluate mechanical behaviors of final composite products and calculate the permeability of the reinforcement. However, due to the high computational cost, it is very difficult to carry out a mesoscopic draping simulation for the entire reinforcement. In this paper, a macro-meso scale simulation of composite reinforcements is presented in order to predict mesoscopic deformations of the fabric in a reasonable calculation time. The proposed multi-scale method allows linking the macroscopic simulation of the reinforcement with the mesoscopic modelling of the RVE through a macromeso embedded analysis. On the base of macroscopic simulations using a hyperelastic constitutive law of the reinforcement, an embedded mesoscopic geometry is first deduced from the macroscopic simulation of the draping. To overcome the inconvenience of the macro-meso embedded solution which leads to unreal excessive yarn extensions, local mesoscopic simulations based on the embedded analysis are carried out on a single RVE by defining specific boundary conditions. Finally, the multi-scale forming simulations are investigated in comparison with the experimental results, illustrating the efficiency of the proposed approach, in terms of accuracy and CPU time.
An Imagined Diaspora: The making of Shi'i Muslim ethnicity in Sri Lanka
Authors: Rasiah Harun
Published: April 2021

The contemporary formation of a community of Shi’i Muslims provides a window into the making and unmaking of ethnicity in Sri Lanka. Originating in solidarity with the Islamic revolution of Iran, Sunni activists formed a political network which has evolved into an autonomous Shi’i religious community. Members studied the traditional Islamic disciplines in the institution of learning (hawza ‘ilmiyya) in Qom alongside students who had undergone a similar transformation, fortifying an internationalist outlook. With associates in the Indian Ocean region, particularly the Gulf states, the transregional community is bound by the common thread of Shi’ism and focuses on Iran and the ‘Atabat of Iraq as spiritual homeland. Exploring the “diasporic consciousness” of the community, this article focuses on the transmission of ideas in time and space. Temporally, it emphasizes claims to local Muslim heritage in variant readings of the Sri Lankan past. Spatially, their cartography provides an alternative account of the sacred landscape based on scholarly practice, devotional activity and political contestation. By recounting the history and mapping the geography of the Shi’i Muslim community, this article investigates how Shi’ism influences the configuration of a diasporic field.
Proteomics characterisation of the L929 cell supernatant and its role in BMDM differentiation
Authors: Heap Rachel E , Marín-Rubio José Luis , Peltier Julien , Heunis Tiaan , Dannoura Abeer , Moore Adam , Trost Matthias
Published: April 2021

BMDMs are a key model system to study macrophage biology in vitro. Commonly used methods to differentiate macrophages from BM are treatment with either recombinant M-CSF or the supernatant of L929 cells, which secrete M-CSF. However, little is known about the composition of L929 cell-conditioned media (LCCM) and how it affects the BMDM phenotype. Here, we used quantitative mass spectrometry to characterise the kinetics of protein secretion from L929 cells over a 2-wk period, identifying 2,193 proteins. Whereas M-CSF is very abundant in LCCM, we identified several other immune-regulatory proteins such as macrophage migration inhibitory factor (MIF), osteopontin, and chemokines such as Ccl2 and Ccl7 at surprisingly high abundance levels. We therefore further characterised the proteomes of BMDMs after differentiation with M-CSF, M-CSF + MIF, or LCCM, respectively. Interestingly, macrophages differentiated with LCCM induced a stronger anti-inflammatory M1 phenotype that those differentiated with M-CSF. This resource will be valuable to all researchers using LCCM for the differentiation of BMDMs.
Eklem patolojilerinde MR artrografinin tanıya katkısı
Authors: CEREN Murat , TEN Barış , YILDIZ Altan
Published: April 2021

Amaç: Özellikle el-ayak bileği olmak üzere omuz ve kalça eklemlerinde Magnetik Rezonans Artrografi (MRArt) tetkikinin eklem içi patolojiler ile eklem yüzeyine bakan tendon-ligaman patolojilerinde tanıda Magnetik Rezonans Görüntüleme (MRG) tetkikine ne kadar ek yarar sağladığı ortaya konulmaya çalışılacaktır. Yöntem: Ocak 2018 ile Haziran 2019 tarihleri arasında Ortopedi ve Travmatoloji Ana bilim dalına başvuran farklı şikayet ve ön tanıları olan 25 olguda el bileğine, 12 olguda ayak bileğine, beş olguda omuz eklemine, yedi olguda kalça eklemine MRG ve MRArt tetkiki yapıldı. Konvansiyonel MRG ve MRArt görüntüleri ayrı ayrı hem hasta bazında hem de toplu olarak değerlendirildi. Yöntemler arası uyum değerlendirilmesinde Kappa hesaplaması kullanıldı. Bulgular: MRArt tetkiki; el bileği ekleminde %68, ayak bileği ekleminde %50, omuz ekleminde %80, kalça ekleminde %28 oranında MRG tetkikine ek bulgu vermiştir. Tüm eklemler beraber değerlendirildiğinde %57 oranında MRArt tetkiki ek bulgu sağlamıştır. Sonuç: Omuz ekleminde özellikle labral patolojilerde ve ligaman yırtıklarında, kalça ekleminde labral patolojilerde, el bileği ekleminde özellikle ligaman yırtıklarında, ayak bileği ekleminde osteokondral defekt (OCD) kontrolünde ve ligaman yırtıklarında MRArt tetkikinin MRG tetkiki ile birlikte değerlendirildiğinde anlamlı katkısı bulunmaktadır.
Influence of cardiopulmonary bypass on the erythrocyte membranes and the method of its protection
Authors: Cherniy V.І. , Sobanska L.O. , Topolov P.O. , Сherniy T.V.
Published: April 2021

The damage to erythrocytes during cardiopulmonary bypass (CPB) remains a recent problem. The aim of this research was to study the effect of fructose-1,6-diphosphate on the state of the erythrocyte membrane during CPB and the level of phosphorus in blood as a marker of the energy potential in the cell. Patients were divided into two groups. The control group 1 (Gr 1) consisted of 75 individuals. The group 2 (Gr 2) included patients to whom fructose-1,6-diphosphate (FDP) was administrated according to the developed scheme as follows 10 g of the drug was diluted in 50 ml of a solvent, 5 g of the drug was injected intravenously with the use of perfusor immediately before initiation of CPB at a rate of 10 ml/min and 5 g at the 30th minute of CPB (before the stage of warming) the same way. When comparing two groups the best results in hemolysis (p<0.01), mechanical (p<0.01). osmotic resistance of erythrocytes (p<0.01), the time of acid hemolysis (p<0.01) and the permeability of the erythrocyte membrane in postperfusion period were in Gr 2. Вefore cardiac surgery hypophosphatemia was detected in 18% out of 150 and in 32% out of 150 patients – a lower limit of normal phosphorus content in the blood. After CPB in Gr 1 phosphorus content in blood was 0.85±0.32 mmol/l and hypophosphatemia was in 53% out of 75 patients. This indicates a pronounced energy deficit in this group. In Gr 2 phosphorus level was 1.7±0.31 mmol/l and there was no hypophosphatemia. As a result, FDP as an endogenous high-energy intermediate metabolite of the glycolytic pathway leads to resistance to hemolysis, protects the erythrocyte membrane from damage and increases the energy potential of the cell during CPB.
Comparison of the efficacy and tolerability of inhaled hypertonic salines of sodium chloride in pediatric practice
Authors: Ilchenko S.I. , Fialkovska A.O. , Cherhinets V.I. , Skriabina K.V.
Published: April 2021

In modern pediatric practice, inhalated hypertonic saline (IHS) is often used for therapeutic and diagnostic purposes. However, the potential development of serious side effects in children is not predicted. The aim of the study was to determine the efficacy and tolerability of IHS of various concentrations in children with cystic fibrosis (CF). The study involved 34 children with CF aged 6 to 18 years (middle age is 13.0±4.4 years). The comparison group consisted of 27 children (middle age is 7.8±2.3 years) without chronic respiratory diseases. The study included three consecutive inhalations. Sterile 0.9% NaCl solution was used for the first inhalation, 3 % NaCl solution – for the second one and 7% NaCl solution – for the third inhalation. For children under 7 years of age, a patented method of obtaining sputum without forced coughing was used. Spirometry was performed before and after each inhalation, and clinical changes were analyzed. It was noted that after inhalation of IHS, the cough in patients became more productive, moist rales were more often heard over the entire surface of the lungs. The activity of induced sputum secretion after inhalation of 3% and 7% NaCl solution did not differ significantly. However, after inhalation of 7% NaCl solution, side effects, such as sore throat, shortness of breath, spastic cough, auscultatory symptoms of bronchospasm were recorded significantly more often compared with lower concentrations of the solution. The decrease in FEV1 was observed in 5.8% of patients after inhalation of 3% NaCl solution and in 11.8% of patients after inhalation of 7% NaCl solution, which was significantly associated with the clinical symptoms of bronchospasm. Inhalation of IHS has an effective mucolytic effect in patients with CF, however, it is necessary to determine the individual sensitivity of the patient to predict a positive therapeutic effect.
Effect of ibuprofen for hemodynamically significant patent ductus arteriosus closure on the development of acute kidney injury in preterm infants
Authors: Borysova T.P. , Obolonska O.Yu.
Published: April 2021

Premature infants with hemodynamically significant patent ductus arteriosus (HSPDA) have a high risk of developing acute kidney injury (AKI) due to renal hypoperfusion and use of ibuprofen for duct closure. The aim of the study was to evaluate the effect of ibuprofen for the closure of HSPDA on the development of AKI in preterm infants depending on high dose of the drug on the first day of life. 40 preterm infants with HSPDA who were admitted for observation on the first day of life were examined. To close the ductus arteriosus, infants received restrictive therapy. In addition, 32 (80,0%) preterm infants on the first day of life were prescribed ibuprofen: 19 infants – in high dose (20 mg/kg), 13 infants – in standard dose (10 mg/kg). Clinical examination and treatment of preterm infants was carried out according to the generally accepted methods. Echocardiography with Doppler was performed at 5-11 hours of life and then daily to determine the size and hemodynamic significance of patent ductus arteriosus. Diagnosis and stratification of the severity of AKI were performed according to the criteria of neonatal modification of KDIGO, for which the concentration of serum creatinine and diuresis were studied. According to the results of the study, it was established that the frequency of AKI on the third and fifth days of life in preterm infants with HSPDA, who received ibuprofen in a high dose (20 mg/kg) on the first day, was 73.7% and 84.2%, respectively, which is 2.2 (OR=5.6; CI: 1,43-21,95; р<0.02) and 2.5 (OR=10.67; CI: 2.31-49.31; р<0.002) times, more often than in infants without such therapy. High dose of ibuprofen on the first day of life in preterm infants with HSPDA are most often associated with the development of stage I AKI on the third or fifth day of life, which was temporary in one third of patients. The use of a high-dose ibuprofen for HSPDA closure on the first day of life in preterm infants was significantly more often associated with foci of infection in the mother, large duct size and furosemide use.
The effect of continuous care model on sleep quality in patients with multiple sclerosis
Authors: Alamdari Maedeh Pourhossein , Ahmadi Fazlollah , Abedini Mahmoud
Published: April 2021

Multiple sclerosis is a chronic and unpredictable disease and is a growing trend and, like other chronic diseases, affects one's quality of life and since sleep quality is one of the dimensions of quality of life, this study aimed to investigate the effect of applying continuous care model on sleep quality of patients with MS in 2013. This clinical trial study was performed on 80 patients with multiple sclerosis who were randomly assigned to experimental and control groups. Data collection tools included demographic information questionnaire, PSQI questionnaire and model implementation in four stages (familiarization, sensitization, control, evaluation). Model stages were performed individually and in groups for three weeks according to patients' educational needs (sleep, activity, medication and nutrition) and after two months follow up, control and evaluation were performed. Data were analyzed using Chi-square test, independent t-test and repeated measures ANOVA and spss16 software. Statistical analysis of variance (ANOVA) with repeated measures showed a significant difference between the mean of total score and the scores of sleep quality dimensions in three times between the two groups (p<0.05). It can be concluded that the implementation of continuous care model causes a significant difference in the sleep quality of patients with MS.