bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Laser Melting of Ti-6Al-4V Lattices: Case Study on a Spinal Cage Prosthesis
Authors: Cantaboni Francesco , Ginestra Paola , Tocci Marialaura , Ceretti Elisabetta , De Sio Giulia , Cao Xue , Carter Luke N. , Villapún Victor M. , Lowther Morgan , Louth Sophie , Cox Sophie C.
Published: July 2022

Biomedical prostheses are artificial devices suitable for the replacement of missing or inefficient parts of the body, implanted to reduce the anatomical or functional deficiency, and sometimes also applied for aesthetic purposes. Despite this type of medical devices represents today a very innovative sector from the medical and engineering point of view, some issues, inherent to the interaction between human body and the external hosts must be considered. It is important that the weight and porosity of the prosthesis respect the patient’s physiological equilibrium which permit an appropriate osseointegration where needed. A typical solution is a lattice structure, which can be manufactured by Additive Manufacturing techniques which, as known, permit to build complex geometries in comparison with other processing routes. Lattice structure are typically characterized by both stiffness and strength significantly lower than the full part of the structure. Generally, for this reason, the lattices are applied to the low-stress areas, leaving a portion of solid sufficient to transmit the loads involved, or in such a way to guarantee the desired flexibility of the part-itself. During the design of lattices some limitations regarding their printability must be considered, such as the minimum printable dimension and the necessary support parts. A Design of Experiment analysis was conducted to identify the optimal parameters to manufacture a spinal cage with negligible porosity via laser powder bed fusion using Ti6Al4V alloy.
Enabling Sustainability in Glass Optics Manufacturing by Wafer Scale Molding
Authors: Strobl Christian , Vogel Paul Alexander , Vu Anh Tuan , Mende Hendrik , Grunwald Tim , Schmitt Robert H. , Bergs Thomas
Published: July 2022

Numerous optical applications have rising demands for ever increasing quantities from lighting and projection optics for modern vehicles to home or street lighting using LED technology. Glass is the material of choice for most of those application fields. It has several advantages over polymers, including heat and scratch resistance as well as longevity and recyclability. Non-isothermal glass molding has become a viable hot forming technology for mass production of optics. The major challenge is enabling a scalable replication process allowing the optical glass elements to be manufactured with high form accuracy and at low-cost production with low reject rates. This work introduces recent developments in glass optics manufacturing that allow the fulfilment of seemingly contradicting criteria: the economic growth and the need for less consumption of resources and energy. While single cavity non-isothermal molding is state-of-the-art, a manufacturing innovation through wafer-scale molding enables an exponentially increasing number of optics to be produced per production shift, allowing a significant reduction of unit costs. In parallel, as multiple optics are produced in one manufacturing cycle, the energy consumption and the consequent CO2 emission can be reduced. In contrast, the technological development arises several challenges that will be discussed in this work. Besides the selection of suitable mold concepts and materials, the challenges also include the temperature control of the mold and the blank up to the optimization of flow and shrinking mechanisms of the glass during rapid forming. Another difficulty in the non-isothermal glass molding is to maintain the low form deviation required for precision optics, repeatability, and low failure rates through process optimization. Finally, detail calculations of cost, energy and CO2 consumption, in comparison with conventional fabrication of glass components using grinding and polishing as well as single cavity molding, will be demonstrated. The non-isothermal wafer-level glass molding is a new technological solution for the sustainable manufacturing of optics at large-scaled production.
Investigation of the Forming Behavior of Copper Wires for the Compaction of Windings for Electric Machines
Authors: Halwas Maximilian , Wirth Felix , Fleischer Jürgen
Published: July 2022

To meet the increasing demand for highly efficient electric traction drives, the compact winding process has been developed at the wbk Institute of Production Science. One key element of the process chain is the compaction of the round wire stator windings. In order to enable an estimation of the sensitivities of the influencing factors, a simplified finite element simulation model was set up in the present work. In the calculations, the number of wire layers, the layer structure and the punch stroke were selected as factors with three levels each. The evaluation was performed by means of false color images and the maximum strains and stresses in the section plane of the slots.
Establishment of Thermal Deformation Constitutive Equation of TA15 Titanium Alloy
Authors: Guo Shuo , Yang Gang , Zhai Yue Wen , Zhou Le Yu , Hao Guo Jian , Qiu De Hua
Published: July 2022

The hot deformation of TA15 titanium alloy was studied by the hot compression test on the Gleeble-3800 thermal simulation equipment. The true stress-strain curves of TA15 titanium alloy at the temperature of 1123-1223K and the strain rate of 0.001-1s-1 were obtained.. The results show that the flow stress increases with decreasing temperature, and increases as the strain rate increases. And the deformation process is accompanied by work hardening and dynamic recovery and dynamic recrystallization. Based on the true stress-strain curves of TA15 titanium alloy, the Arrhenius-typed constitutive equation was established. The thermal deformation activation energy of TA15 titanium alloy with a strain of 0.2 is 746.27kJ/mol.
In Situ Wear Measurement of Hot Forging Dies Using Robot Aided Endoscopic Fringe Projection
Authors: Middendorf Philipp , Rothgänger Marcel , Peddinghaus Julius , Brunotte Kai , Uhe Johanna , Behrens Bernd-Arno , Quentin Lorenz , Kästner Markus , Reithmeier Eduard
Published: July 2022

According to the current state of the art, wear conditions of forging dies are assessed visually in the dismantled state, as there is no measuring procedure available for inline wear measurement of hot forging dies. This paper introduces a handling concept for automated loading and in-situ tool inspection for a hot forging process. Based on an industrial robot and quickchange systems, the process integration of hightemperature grippers and an endoscopic 3D-measurement sensor for the in-situ inspection of hot forging dies is carried out. By adapting the measuring method of fringe projection to an endoscopic design, the measuring system can be navigated into the difficult-to-access geometry of the die and take high-precision 3D-measurements inside. The ambient air heated by the forming process creates an inhomogeneous refractive index field around the measuring system and the hot die, so that the straight beam path required for optical measuring systems cannot be ensured. This can lead to strong deviations in the reconstructed point clouds and the functional geometries derived from them. By means of a compressed air actuator, the measuring system can be protected from the hot tool and dirt as well as the effect of inhomogeneous refractive index can be reduced. With this approach the in-situ wear measurement at highly stressed regions using the example of the mandrel radius and the flash radius will be demonstrated. These functional elements are of particular relevance, as the thermalstress is high and large material flow takes place. For the wear measurement, the functional elements of the tool are examined in detail by fitting geometrical features into the reconstructed point clouds and determining the deviations from a reference geometry. In addition, the measurement data is validated with the aid of a commercially available state-of-the-art measurement system.
Influence of the Laser Welding Direction of Thin DP600 and the Residual Stresses Relaxation Obtained by Simulation and Neutron Diffraction
Authors: Liu Miao Ran , Kouadri-Henni Afia , Malard Benoît
Published: July 2022

Laser-welded structures are often subjected to dynamic service loads ranging from cyclic fluctuations to completely random ones. The laser-welded lap joints suffer from defects resulting in notch effects, surface cracks, residual strains and stresses. The fatigue strength of the laser-welded lap joints is reduced significantly because of the presence of these defects, and the size of the welded joints is small. Therefore, the mechanical strength of laser-welded structures must be defined in terms of the fatigue strength and residual stress of the obtained joints or assemblies. To analyze the above-discussed effects, this paper proposed two approaches: numerical and experimental methods. The originality of the work is to weld the rolled sheet in three directions (0°, 45°, 90°). The residual stresses before and after low cyclic tensile tests of assemblies obtained from overlapped thin DP600 steel sheets were calculated by ABAQUS. The obtained results were compared to the experimental data by neutron diffraction. The presented results in terms of residual stresses curves, spatial distributions of residual stresses obtained at the end of laser welding and low-cycle fatigue. It showed the relaxation effect of residual stresses and the direction effect of welding. These results have been explained by several factors.
In Silico Finite Element Approach on Mechanical Behavior in Superelastic Nitinol
Authors: Chekotu Josiah Cherian , Brabazon Dermot
Published: July 2022

Over the recent years, Nitinol (Ni-Ti) shape memory alloys have gained popularity in the medical, aerospace and energy sectors, due to their superelasticity, shape memory effect, low stiffness, good biocompatibility and corrosion resistance. Compared to steels and other common metallic materials, it is difficult to model the mechanical behavior of Ni-Ti due to the inherent functional properties caused by the diffusion-less solid-state phase transformations. With the help of Laser Powder Bed Fusion (L-PBF) process, these transformational characteristics can be controlled. This will ultimately lead to controlling the mechanical and thermal properties for specific applications. In this work, Finite Element Analysis (FEA) was conducted to replicate the actual mechanical phenomenon occurring in Nitinol. Models were generated for simulating the superelastic and plastic behaviors, and were validated against actual experimental data. The ability to model the complex mechanical response of Nitinol will enable exploration into the sensitivity of material response to phase volumes, material composition, and strain rate. Robust models of these phenomenal also provide the potential for tailoring in-silico the microstructure required for specified desired macroscopic material properties.
Modelling the Effect of Barrier Layers on the Tensile Properties of Paperboard Materials for Liquid Packaging
Authors: Singh Praveen , Ghiotti Andrea , Simonetto Enrico , Bruschi Stefania
Published: July 2022

Investigations of the mechanical behaviors of the paperboard packaging materials has propelled to the forefront of the packaging industries owing to the anisotropic behavior of the paperboard materials. Paperboard materials undergo tensile forces during the creasing and folding operation. Therefore, the knowledge of the material tensile properties it is undeniably important to perform the operation without tearing the layers. Anisotropic behavior of the paperboard material is required to be addressed for the packaging material to be used effectively and efficiently. Paperboard material being anisotropic in nature have different properties in the Machine Direction (MD) and Cross Direction (CD). The paper focuses on the modelling of double layered paperboards with barrier elements either in aluminum or in Ethylene vinyl alcohol copolymers (EVOH). A numerical model of the packaging material was developed in LS-DYNA environment showing good fitting with the physical tests.
Prediction of Forming Forces for Incremental Micro-Forming Using Finite Element Analysis
Authors: Bansal Ankush , Cheng Randy , Banu Mihaela , Taub Alan , Ni Jun
Published: July 2022

As incremental forming is a relatively new sheet metal forming process, very limited analytical and finite element prediction models are available in literature to study the process mechanics and improve its performance. Thus, most studies involve many trial-and-error iterations to optimize the processing conditions in order to take advantage of high process flexibility and material formability. However, reducing efforts of trial-and-error iterations is of utmost importance to make a process financially viable. Therefore, an FE model is developed and experimentally validated to predict the forming forces involved in incremental micro-forming process. Different mass scaling factors and element-types are used to optimize and develop the model for accurate prediction in the least possible computation time.
Numerical and Experimental Investigations on the Mechanical Properties of Milled Specimens from an AA7020 Tube
Authors: Reblitz Jonas , Reuther Franz , Trân Ricardo , Kräusel Verena , Merklein Marion
Published: July 2022

The reduction of weight is crucial in the automotive sector to reach a lower energy consumption and an increased range, especially for electrically powered vehicles. In this regard, body-in-white parts offer a high potential for the application of lightweight construction. The required weight savings can be achieved by implementing parts with a high strength-to-weight ratio. A promising approach is the combination of lightweight materials and lightweight design, which can be realized by tubular components made of high strength aluminum. Due to their structural stiffness and high crashworthiness, those structures are often used as safety-relevant car body components. However, the material characterization of tube profiles is a major challenge, which in turn impedes an accurate numerical simulation and precise process design. In contrast to flat semi-finished parts, various effects of the production process and the geometry, regarding the stress state under load, must be taken into account. For this purpose, adapted testing methods considering the geometrical and mechanical properties of the tubular parts have to be investigated, in order to generate an accurate material model and process design. Within this research work, tubular components made out of AA7020 in W-temper condition were used to analyze the mechanical properties. In this regard, several tensile specimens are milled from a tube, so they also have a curvature profile. The experimental tensile tests have been performed at different strain rates by using an universal testing machine from type Gleeble 3500. To ensure a proper measurement of the mechanical properties, the clamping jaws of the testing machine are adjusted to the curved samples. The investigated material parameters are subsequently transferred to an FE-Model with curved specimen to enable an accurate prediction of the forming behavior. In addition, an FE model of a flat tensile specimen was also created for comparison, in order to gain a profound knowledge regarding the influence of the geometric and mechanical properties of tubular components.
Modeling Friction in HyperXtrude for Hot Forward Extrusion Simulation of EN AW 6060 and EN AW 6082 Alloys
Authors: Hoque Sheikh Enamul , Hovden Sindre , Culic Stefan , Nietsch Jürgen A. , Kronsteiner Johannes , Horwatitsch Dieter
Published: July 2022

In this work, different friction models available in HyperXtrude had been investigated in the context of hot forward extrusion simulation of aluminum alloys. Extrusion trials were carried out for EN AW 6060 and EN AW 6082 at different temperatures and ram speeds. The extrusion forces as well as material temperatures near the exit of the die were recorded and used for the validation of the simulations. FE-simulations of each extrusion trial were carried out in HyperXtrude. Initially, friction models were calibrated for only two extrusion trials. Then, these calibrated friction models were used to simulate the extrusion trials with different process parameters. Reasonably good agreements were observed between experiments and simulations in terms of extrusion forces. However, the simulations overpredicted the material temperature by almost up to 40 °C for extrusion trials with high ram speed.
Comprehending the Bending: A Comparison of Different Test Setups for Measuring the Out-of-Plane Flexural Rigidity of a UD Fabric
Authors: Krogh Christian , Broberg Peter Hede , Kepler Jørgen , Jakobsen Johnny
Published: July 2022

To simulate the forming process of a unidirectional (UD) glass fiber non-crimp fabric (NCF) for wind turbine blades, the fabric material needs to be characterized. In this way, input to the material model of the simulation can be generated. One important deformation to characterize is the out-of-plane bending. A number of test setups have been described in the literature but it is not clear which setup is more appropriate for the UD NCF under consideration. Therefore, five different out-of-plane bending test setups are compared and discussed, namely Peirce's cantilever test (with an inclined plane), the free-hanging cantilever test, a vertical cantilever test, a rotary rheometer bending test and a buckling test. For the latter an inverse modeling approach is developed. The test results shows that similar flexural rigidities can be computed from the different test setups but that some values are sensitive to the parameters used in the data processing techniques.
Numerical Investigations on Stresses and Temperature Development of Tool Dies during Hot Forging
Authors: Behrens Bernd-Arno , Rosenbusch Daniel , Wester Hendrik , Siring Janina
Published: July 2022

Hot-forming tools are subjected to high thermal and mechanical stresses during their application. Therefore, a suitable design of the tool die is important to ensure a long tool life. For this purpose, numerical simulations can be used to calculate the occurring stresses and the temperature development in the tools during the course of a stroke or over several forging cycles. The aim of this research is to investigate the effect of different radii on the resulting stresses in the lower die of the forming tools. Furthermore, the temperature evolution over several cycles is analysed to determine their effect on the temperature. When investigating the stress, it was found that a larger radius leads to a reduction in stresses. In addition, it could be numerically proven that the base temperature of the die levels off after a certain number of cycles. These findings will be used in further research dealing with the service life calculation of dies subjected to thermo-mechanical alternating stresses.
Numerical Analyses of Deformation Mechanisms in a Novel Dimensional Calibration Technique for Thin-Walled, Open Extrusions
Authors: Zhou Xian Yan , Ma Jun , Welo Togeir
Published: July 2022

High dimensional accuracy is of crucial importance in digital manufacturing to guarantee production capability and product performance. For manufacturing of thin-walled complex extrusions, it is often challenging to meet the tight dimensional tolerance requirements for automated mass production, due to dimensional imperfections and variations accumulated from the thermo-mechanical processing history. Recently, a new calibration technique, called Transverse Stretch and Local Bending, was developed, enabling significant improvement of the dimensional accuracy of thin-walled open profiles at a low cost. However, the deformation mechanisms have not been well understood, which in turn affect the process design for achieving high-precision products. In this study, a through-process finite element model was established and experimentally verified, which is used as a tool to investigate the mechanisms in the calibration process. It is found that the gap opening is mainly reduced in the inserting stage, but the calibration stage plays a key role in achieving high-precision products after unloading. The critical factor to achieve high dimensional accuracy is reducing the through-thickness gradients on both the profile bottom and sidewall. By controlling the total vertical displacement in the transverse stretch and local bending, the stress gradients can be effectively reduced, and the dimensional deviation caused by springback after unloading can be well mitigated. This fundamental study will benefit the industry to obtain high-precision extrusions.
Determination of Forming Limit Curves - Strain Path and Failure Analysis
Authors: Kohl Doris , Merklein Marion
Published: July 2022

With the goal to define a cost-effective and efficient process to identify adequate materials for sheet metal forming processes, it is crucial to evaluate the formability of materials. Forming limit curves (FLC) are used to analyze the forming and failure limits of sheet metals and dependence of the major (φ1) and minor strain (φ2) from the uniaxial stress-strain area through the plane-strain point to the biaxial strain area. According to ISO 12004-2, the FLC is performed by Nakajima or Marciniak tests. Due to the experimental setup and the preconditions, pre-stretching occurs in the specimens and bending and friction effect are the result. The determination of the onset of necking (FLC) results mathematically from a “best-fit inverse parabola” on section lines. In addition, the failure point, i.e. the maximum strain value one frame before failure, is also analyzed. In contrast, tensile, notched tensile and hydraulic bulge tests, which together have a potential to map an alternative FLC, exhibits a linear strain path evolution. The behavior of the various strain paths of Nakajima and the alternative methods are examined for necking and cracking. Furthermore, the fracture surfaces are investigated by confocal laser scanning microscopy to identify influences of the different FLC methods on the fracture mechanics. FLCs were conducted with the Nakajima and the alternative FLC characterization method for a ductile steel (DX54D). To ensure transferability, the tensile tests are also performed with a high-strength steel (DP800). The FLC of the ductile steel, generated through the alternative method, exhibits a similar shape to the Nakajima generated FLC with the advantage of a constant strain rate leading to linear strain paths and a lower number of tests. The same results are achieved for the uniaxial strain tests with DP800.
Nitrogen Supersaturation into AISI420 Mold for Precise Machining
Authors: Aizawa Tatsuhiko , Morita Hiroshi , Fukuda Tatsuya
Published: July 2022

The plasma nitriding conditions and processing parameters were controlled to attain the high-density nitrogen ion and NH-radical populations and to form the nitrogen supersaturated layer into AISI420 type martensitic stainless steel mold substrate at 673 K for 14.4 ks and 28.8 ks. Thicker nitrided layer than 80 mm was attained for fine machining of the optical diffraction elements onto this nitrided AISI420 mold surface. The average hardness in this nitrogen supersaturated layer reached 1400 HV. After this hardness testing and microstructure analysis, the machinability test was performed to describe the ductile mode cutting behavior of nitrogen-supersaturated work by using the PCD (Poly-Crystalline Diamond)-chip tool. Higher average nitrogen solute content than 4 mass% was responsible for fine turning by PCD-chip and CVD (Chemical Vapor Deposition)-diamond coated cutting tools without any damages and for precisely finishing the mold surface with the lower maximum surface roughness than 10 nm on the machined mold surface. The low roughness and homogeneous machined surface profile proved that the nitrogen supersaturated AISI420 series stainless steel was adaptive as a stamping mold of chalcogenide glasses with high dimensional accuracy and demolding capacity.
A Novel Method for the Determination of High Temperature FLCs of ECAP-Processed Aluminum AA5083 Sheet Metal
Authors: Gruber Maximilian , Leitner Philipp , Auer Matthias , Illgen Christian , Frint Philipp , Wagner Martin F.X. , Volk Wolfram
Published: July 2022

In this study, investigations into the deformation behavior of aluminum AA5083 at elevated temperatures were carried out on a newly developed test rig. The test rig was developed jointly with ZwickRoell GmbH & Co. KG (Germany) and is based on a Nakajima test carried out with heated dies. In this way, statements can be made about the lightweight potential of the alloy. Additionally, equal-channel angular pressing (ECAP) was performed to process the aluminum sheet metal. The conventional ECAP process is mainly used for bulk material in laboratory use and therefore is often not suitable for many industrial applications, especially for large series. The use of sheet metal allows a significant increase in the areas of application. It is documented in conventional ECAP that grain refinement is achieved by the severe plastic deformation. At room temperature this primarily increases the mechanical strength. Formability is improved in fine-grained materials, especially at elevated temperatures, which is related to diffusion-controlled deformation mechanisms and grain boundary sliding. The advantages of ECAP for sheet materials are thus also in lightweight construction and can even optimize the use of the AA5083 alloy. ECAP-route C was used for the process to provide the most homogeneous microstructure possible (180° rotation around the ECAP-axis after the first pass). Nakajima specimens were taken from the processed sheet materials to determine the Forming Limit Curve (FLC) compared to the reference material (four different specimen geometries). FLCs under elevated temperatures (250 °C, 375 °C) were performed on the novel Nakajima test bench. A special feature of the test rig is the rapid heating to avoid microstructural changes. Microscopic examinations were performed after the deformation to study the deformation mechanisms. Differences of the forming and fracture mechanisms between the reference alloy and the ECAP material were found.
Functionality Study of an Optical Measurement Concept for Local Force Signal Determination in High Strain Rate Tensile Tests
Authors: Böhnke Max , Unruh Eduard , Sell Stanislaw , Bobbert Mathias , Hein David , Meschut Gerson
Published: July 2022

Many mechanical material properties show a dependence on the strain rate, e.g. yield stress or elongation at fracture. The quantitative description of the material behavior under dynamic loading is of major importance for the evaluation of crash safety. This is carried out using numerical methods and requires characteristic values for the materials used. For the standardized determination of dynamic characteristic values in sheet metal materials, tensile tests performed according to the guideline from [1]. A particular challenge in dynamic tensile tests is the force measurement during the test. For this purpose, strain gauges are attached on each specimen, wired to the measuring equipment and calibrated. This is a common way to determine a force signal that is as low in vibration and as free of bending moments as possible. The preparation effort for the used strain gauges are enormous. For these reasons, an optical method to determine the force by strain measurement using DIC is presented. The experiments are carried out on a high speed tensile testing system. In combioantion with a 3D DIC high speed system for optical strain measurement. The elastic deformation of the specimen in the dynamometric section is measured using strain gauges and the optical method. The measured signals are then compared to validate the presented method. The investigations are conducted using the dual phase steel material HCT590X and the aluminum material EN AW-6014 T4. Strain rates of up to 240 s-1 are investigated.
Application of Calcium Carbonate as Green Lubricant Additive in Sheet Metal Forming
Authors: Arinbjarnar Úlfar , Moghadam Marcel , Nielsen Chris Valentin
Published: July 2022

The application of calcium carbonate particles as a green lubricant additive for sheet metal forming processes has been evaluated. Different particle sizes were tested, along with different concentrations of particles in a lubricant that typically does not perform well by itself. The lubricant mixtures were tested under pin-on-disc, four-ball, and bending-under-tension test conditions. The results of the different tribological tests were compared to determine whether standard tests, such as the four-ball test, could predict lubricant performance under sheet metal forming conditions. The application of any concentration of particles was shown to be beneficial to the lubricant performance in terms of wear resistance even though friction increased when calcium carbonate particles were added to the base paraffin oil. Small particles (40 nm) exhibited better performance than large particles (2 μm).
Tribocorrosion Behavior of Ti6Al4V Machined and Burnished Components for Biomedical Application
Authors: Rotella Giovanna , Saffioti Maria Rosaria , Sanguedolce Michela , Umbrello Domenico , Filice Luigino
Published: July 2022

Nowadays, the increased average age of patients and the decreased age at which arthroplasty is carried out represents a reason for the necessity of higher quality standards for prostheses. In particular, tribocorrosion generates an irreversible transformation of the materials and the release of particles and metal ions in toxic concentrations in the biological environment in which the systems are implanted. One of the most used materials for prosthetic implants is the Ti6Al4V alloy but its tribological behavior is still challenging for the application. Employing and optimizing severe plastic deformation processes represents a way to obtain prostheses with superior performance improving patients’ quality of life and reducing the burden on National Health Cares. Ti6Al4V bars have undergone machining with semi-finishing parameters and burnishing processes. Tribocorrosion tests have been performed in a custom-made cylinder-on-disk configuration employing Al2O3 counterparts and phosphate buffer solution with the addition of albumin as simulated body fluid. The effects of sole machining and its combination with burnishing on surface quality and specific wear rate (SWR) have been assessed with respect to as received surface conditions. Optical microscopy, stylus profilometry and sample weighing before tests and at specific intervals during the tests have been employed for characterization. As a main result, it has been found that burnishing process is able to improve SWR of Ti6Al4V samples with respect to both as received and machined samples. Furthermore, the overall behavior of tribological system is gradually improved first employing sole machining and then combining machining and burnishing, reducing SWR of counterparts as well.
Numerical Study to Promote the Residual Stresses Development during ISF Process with Improvement in Two Point Incremental Die Forming
Authors: Afzal Muhammad Junaid , Buhl Johannes
Published: July 2022

Metastable austenitic stainless steel (MASS) has been the material of choice for the fabrication of disc springs employing incremental sheet forming (ISF) processes due to its high creep, fatigue, and chemical resistance, as well as its good surface quality. Previous research has shown that the presence of martensite enhances the formation of beneficial compressive residual stresses. However, if the ISF is accelerated to improve efficiency, the rise in temperature during ISF operation suppresses the deformation that causes martensite transition (DIMT). In essence, the cooling channel shapes are developed with numerical assistance such that its impact on residual stress induction is low. Variation in ISF process parameters, such as tool diameter, tool step-down, and contact force, as well as variation in cooling channel size, are used to construct the computational analysis. To analyze the finally produced residual stresses in the disc spring, the non-linear isotropic/kinematic hardening combined with the TRIP formulation is simulated. According to the comparison, the channel size must be between 0.8 and 1.2 mm in radius to minimize residual stress fluctuation. Additionally, when moving across the die with cooling channels, the force-controlled ISF produces more consistent results. Based on the numerical findings, it is conceivable to greatly enhance the ISF process speed and dissipate process heat by cooling the sheet on sides, allowing residual stresses and martensite content to be adjusted in a stable manner. As a result, the ISF process may be greatly expedited, making it more appealing for industrial applications.
Management of postkidney transplant anemia – is it feasible to maintain patient and allograft survival?
Authors: Abbas Fedaey , El Kossi Mohsen , Shaheen Ihab S. , Sharma Ajay , Halawa Ahmed
Published: July 2022

Background

Kidney transplantation has been established as the best therapy for end-stage renal disease. After transplantation and to provide a prolonged and safe patient and allograft survival, early and prompt diagnosis of posttransplant sequelae, for example, posttransplant anemia (PTA) in particular, is currently crucial. Timing of presentation of this disease has its effect on PTA development. The ‘early’ presented PTA (before 6 months) may differ clinically from the ‘late’ one (after 6 months) with respect to the underlying background. Although early PTA is multifactorial, allograft dysfunction is usually the underlying mechanism in the ‘late’ one. Furthermore, PTA is currently considered as an independent risk factor for the evolution of cardiovascular system events; the latter has been proved to be the first leading cause of death in this cohort of patients. The aims and objectives of this review is to evaluate critically the risk factors responsible for PTA development, its epidemiology, diagnostic criteria, etiology for both ‘early’ and ‘late’ PTA, the available therapeutic approaches for PTA, as well as the effect of PTA in allograft and patient survival.

Methods

Current available literature and analysis of various trials concerned with PTA.

Results

The impact of anemia on patients as well as allograft outcomes cannot be simply overlooked. Management of the early as well as late PTA is crucial. However, a variety of hazards of its therapeutic options should be thoroughly considered.

Conclusions

A lowered threshold of post-transplant anemia (PTA) awareness and its early management has its crucial impact on allograft as well as patient survival. Benefits of PTA correction is not only reflected on patients’ and allograft longevity but also on upgrading KTRs’ quality of life.
Frameworks de Gamificação enquadrados numa Visão Sistémica: Uma Revisão
Authors: Bacelar Saraiva Fernando
Published: July 2022

O presente artigo faz uma revisão focada sobre frameworks de Gamificação que podem ser enquadradas numa visão sistémica, no âmbito dos sistemas de informação. Gamificação é o uso de elementos derivados dos jogos em contextos que não são jogos. Nesse sentido, foi proposta uma terminologia que possa ser usada em várias implementações e cenários. É discutida a forma como a terminologia proposta está alinhada com os frameworks dos artigos revistos e a pertinência de usar uma visão sistémica única para futuras intervenções de Gamificação.

Gamification Frameworks in a Systemic Approach: A Review

This article is a review focused on Gamification frameworks that can be framed in a systemic approach, within the scope of information systems. Gamification is the use of game-derived elements in nongame contexts. In this sense, a terminology that can be used in various implementations and scenarios is proposed. It discusses how the proposed terminology is aligned with the frameworks of the reviewed articles and the relevance of using a unique systemic approach for future Gamification interventions.
Lectura, Aprendizajes y Subdesarrollo
Authors: Sánchez Quezada María de los Ángeles
Published: July 2022

Hay dos aspectos centrales en la educación de las personas que marcan su futuro. Uno, es sin duda su comportamiento habitual y sistemático para la lectura. El otro, es la producción textual. En uno y otro caso se requieren no solo interés y novedad, sino también perseverancia. Lamentablemente los rankings internacionales en las últimas décadas ubican a nuestro país con bajos niveles de comprensión lectora en la educación básica regular y educación universitaria.
Los Cañones de Navarone
Authors: Azabache Zelada Ramón Daniel
Published: July 2022

Trata sobre el eficaz sistema de defensa que tenían los alemanes, en la segunda guerra mundial, en las aguas del mar Mediterráneo, difícil de ser traspasado por las tropas aliadas. Este poderío lo constituía el fortín de Navarone, que gracias a sus gigantescos cañones cerraban el paso a la navegación por el mar Egeo. En la isla de Keros se encontraban más de 2 mil soldados aliados a los que no se les podía rescatar por la amenaza de los cañones de Navarone. Ante esta imposibilidad se reúnen seis hombres para intentar romper el cerco, y lo logran.
Telerehabilitation and Covid-19: An Emerging Approach for Health Care System in India
Authors: Jadhav Dr. Priyanka , Anap Dr. Deepak
Published: July 2022

Telerehabilitation is termed as habilitation or rehabilitation services that are provided by a rehabilitation professional remotely, which is useful for assessment, monitoring, prevention, intervention,supervision, education, consultation, and counseling. It comprises the use of videoconferencing via the internet,phone calls, and virtual reality systems, where remoteinteraction with patients can either be real-time or prerecorded. It is cost saving, easy accessibility and gives a quality health services. In modern India, technology is connecting people over different areas. This also helps in health sector to get connected with their health facility by being at home.
Relationship Between Duration of Stroke and Hand Function Recovery in Patient with Stroke
Authors: Zawar Pranoti , Harishchandre Dr. Maheshwari , Ganvir Dr. Suvarna
Published: July 2022

Background- Stroke is sudden loss of neurological function caused by an interruption of the blood flow to the brain. The fine motor activities are also affected which leads to difficulty in writing, prehension and precision are also affected so patient is also not able to hold the or any object in the hand which required to performed in daily activities. Methods - This is an Observational study with a study duration was of 1 year. A total of 30 participants were recruited using the purposive sampling method from the Department of neuroscience, Vikhe Patil Memorial Hospital, Ahmednagar; Puntamba stroke center, Puntamba and Rahuri stroke center. Result - The study shows in jebson taylor hand function test, the most affected component is writing which requires more time followed by moving heavy objects and stimulated feeding, in addition requires less time for card turning, followed by small common object and checkers stacking and the least time required for performing moving light object in stroke patients. Conclusion- The study concludes that there is no relationship between duration of stroke and hand function recovery in patients with stroke. The jebson taylor hand function test shows that the most time required is for small dexterity movement like writing, stimulated feeding. The patients find difficulty in moving heavy objects. The less difficulty task is card turning, checkers stacking, moving light objects, which requires use of all the fingers.
Consequences of COVID-19 in the Status of Physical Fitness in Post COVID Patients: A Cross Sectional Study.
Authors: Patare Srushti , Harishchandre Dr. Maheshwari , Ganvir Dr. Suvarna
Published: July 2022

Introduction- The COVID-19 pandemic caused by the highly infectious SARS-CoV-2 has affected over 15.9 million people across 200 countries and caused more than 643,000 deaths. The coronavirus is a highly infectious virus and spreads through droplets generated during coughing, sneezing, talking, and even breathing. .[1] As the main symptoms reported after COVID-19 are fatigue and dyspnoea, the need of the study is to find out consequences of COVID 19 in status of Physical Fitness with respect to Functional status, endurance and Lung capacity in Post COVID- 19 subjects
 
Aim – To analyse the consequences of covid-19 in the status on physical fitness in post COVID patients.
 
Objectives- 1. To find out effect of COVID on lung function capacity assessing PEFR in post COVID patients.

To find out effect of COVID on functional status in post COVID patients.

 3.To know the effect of COVID on endurance using Figure of 8 walk test in post COVID patients.
 
Methods- The research was carried out in the Physiotherapy OPD at Vikhe Patil Memorial Hospital. A cross-sectional study was designed. Purposive sampling was used in the sampling process. The sample size for this study was 50. Consent form for a six-month study was made. Peak flow metre, Sterilium, Cotton wool, Weighing machine and Measuring tape, Post COVID-19 Functional status scale, 2 cones, stop watch, Pedometer, tape measure were among the materials utilised. Patients with COVID 19 infection who were recovered and willing to participate, both genders, ages 20 to 55, and able to walk without assistance met the inclusion criteria. Patients who were not cooperative or who had additional systemic illnesses, such as diabetes, were excluded.
 
Result- A total of 50 patients entered the study who were in the age group of 20-55 yrs. We compare PEFR values among symptomatic and asymptomatic patients. The study shows that comparison of PEFR values between symptomatic and asymptomatic patients was not significant (p value 0.2265) and PEFR values of symptomatic patients were less than that of asymptomatic patients. The patients who were symptomatically ill were affected more and show symptom of pain, anxiety, depression rather than asymptomatic patients and there was no sign of functional limitation. There is no effect on endurance of the patients as such
after recovery from COVID-19 infection.
Conclusion- This study shows that there is effect of COVID on physical fitness of post COVID patients after recovery with respect to lung function capacity. Symptomatic patients were more affected than asymptomatic patients. The functional status of the post COVID patients is not affected, few of them suffered from pain, depression and anxiety after recovery. There is no effect on endurance in post COVID patients after recovery.
Sealant Penetration into Occlusal Fissures: An In-Vitro Optical Coherence Tomography Study
Authors: Sukumaran Prema
Published: July 2022

Objective: This study was designed to use Optical Coherence Tomography (OCT) to quantify depth of occlusal fissures on premolar teeth and to quantitatively evaluate the penetration of pit and fissures sealants relative to fissure depth. The study aimed to evaluate the penetrability of Pit and Fissure Sealant (PFS) in covering the full-depth of different occlusal fissure depths using Swept-Source Optical Coherence Tomography (SS-OCT).

Methods: Ninety-seven investigation sites on f occlusal fissures of fifteen premolar teeth with International Caries Detection and Assessment System (ICDAS) scores of 01 or 02 were categorized using SS-OCT into four groups (smooth, shallow, intermediate, and deep fissures). After PFS placement, cross-sectional images of these fissures were observed again with SS-OCT.

Results: The result of this study shows that PFS can fully penetrate the smooth fissures (100%) followed by shallow fissures (94.2%) and intermediate fissures (47.6%). Incomplete full depth PFS penetration can be seen in all deep fissures (100%).

Conclusion: The depth of the fissure will largely affect the penetrability of PFS into the fissure.
Singapore Cancer Network (SCAN) Guidelines for Systemic Therapy of Pancreatic Adenocarcinoma
Authors:   The Singapore Cancer Network (SCAN) Pancreatic Cancer Workgroup
Published: July 2022

Introduction: The SCAN pancreatic cancer workgroup aimed to develop Singapore Cancer Network (SCAN) clinical practice guidelines for systemic therapy for pancreatic adenocarcinoma in Singapore. Materials and Methods: The workgroup utilised a modified ADAPTE process to calibrate high quality international evidence-based clinical practice guidelines to our local setting. Results: Five international guidelines were evaluated—those developed by the National Cancer Comprehensive Network (2014), the European Society of Medical Oncology (2012), Cancer Care Ontario (2013), the Japan Pancreas Society (2013) and the British Society of Gastroenterology, Pancreatic Society of Great Britain and Ireland, and the Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland (2005). Recommendations on the management of resected, borderline resectable, locally advanced and metastatic pancreatic adenocarcinoma were developed. Conclusion: These adapted guidelines form the SCAN Guidelines for systemic therapy for pancreatic adenocarcinoma in Singapore.

Key words: Singapore context, Treatment recommendation
Fetal Non-invasive Electrocardiography Contributes to Better Diagnostics of Fetal Distress: A Cross-sectional Study Among Patients with Pre-eclampsia
Authors: Lakhno Igor
Published: July 2022

Introduction: Fetal distress is a result of acute or chronic disturbances in the system of “mother-placenta-fetus” in pre-eclampsia (PE). The aim of the investigation was to compare the accuracy of antenatal fetal distress diagnostics in cases of traditional cardiotocography (CTG) waveform evaluation and analysis of morphological non-invasive electrocardiogram (ECG) parameters in anterpartum patients with PE. Materials and Methods: Fetal non-invasive ECG antenatal recordings of 122 pregnant patients at 34 to 40 weeks of gestation were examined. In Group I, there were 32 women with physiological gestation and normal fetal condition according to haemodynamic Doppler values. Group II involved 48 patients with mild and moderate PE whom were performed Doppler investigation. In Group III, 42 patients with severe PE were monitored with haemodynamic Doppler. Results: Fetal autonomic tone was lower with the relative increase of low frequency (LF) branch in the patients of pre-eclamptic group. The increased value of the amplitude of mode (AMo) and stress index (SI) was associated with adrenergic overactivity. It has induced pQ and QT shortening, increased T/QRS ratio and decelerations appearance. The rate of antenatal fetal distress retrospectively was 31.1 % in PE. The traditional analysis of CTG parameters has showed sensitivity (72.7%) and specificity (87.1%). In addition to the conventional CTG analysis, evaluation of ECG parameters has contributed to better diagnostics of fetal distress. Sensitivity and specificity of non-invasive fetal ECG were absolutely equal in this study (100%). Conclusion: The results suggest that fetal non-invasive ECG monitoring is more objective than conventional CTG. Key words: Fetal heart rate variability, Fetal monitoring, Hypertensive disorders of pregnancy