Dimensional Changes Research Articles

Can the Dimensional Optimisation of 3D FDM-Manufactured Parts Be a Solution for a Correct Design?

Additive manufacturing technology, also known as 3D printing, has emerged as a viable alternative in modern manufacturing processes. Unlike traditional manufacturing methods, which often involve complex mechanical operations that can lead to errors and inconsistencies in the final product, additive technology offers a new approach that enables precise layer-by-layer production with improved geometric accuracy, reduced material consumption and increased design flexibility. Geometrical accuracy is a critical issue in industries such as aerospace, automotive, medicine and consumer goods, hence the importance of the following question: can the dimensional optimisation of 3D FDM-manufactured parts be a solution for correct design? This paper presents a complex study of model parts printed from four common polymers used in fused deposition modelling (FDM) additive technology, namely ABS (acrylonitrile–butadiene–styrene), PLA (polylactic acid), HIPS (high-impact polystyrene) and PETG (polyethylene terephthalate glycol). The results of the methodology used highlight the dimensional changes that need to be made at the design stage, depending on the direction of printing and the type of geometric elements in the final part.

Highly Deformable Phototunable Viscoelastic Fluid Interface Modulates Cellular Adaptive Wetting Behavior

AbstractEmerging evidence shows that the viscoelastic cues of the e Ixtracellular matrix (ECM) regulate cellular functions and fates. However, as cells are viscoelastic, force dissipation occurs within themselves as well as the ECM side, implying the existence of reciprocal viscous regulation between the two. Here, a fluid‐based scaffold with tunable viscoelasticity has been developed to investigate its impact on the cell adhesion process. The platform is based on the water–perfluorocarbon interface decorated with diacetylene‐based phospholipid membranes (IPLMs), whose viscoelasticity can be systematically manipulated by photocrosslinking. Further introduction of a cell‐adhesive peptide and fluorescent tag allows cell adhesion at the highly deformable fluid interface and confocal observation of dynamic cell–model ECM interactions. The viscoelasticity‐tunability is confirmed by fluorescence recovery after photobleaching, interfacial rheology, and atomic force microscopy nanoindentation. Cells seeded at the IPLM exhibit so‐called adaptive wetting, where the interface first deforms toward the out‐of‐plane direction before cellular dimensional changes, followed by cellular flattening and interfacial restoration. Furthermore, the quantification of these parameters reveals a biphasic response against the crosslinking levels, which indicates that the cell‐ECM viscosity balance determines adaptive wetting phenotypes. The platform may enable the prediction of dynamic adhesion responses in physiological and pathological processes.

Performance Assessment and Failure Mechanisms of Roller Bearings Using Dual Material Comparison

This study presented the performance and failure mechanisms of roller bearings for structural steel and AISI 52100 alloy steel under various operating conditions. It emphasizes how material properties affect stress, deformation, and thermal performance according to simulations carried out in ANSYS Workbench. Results clearly present that AISI 52100 alloy steel exhibits better strength against stress, dimensional stability, and thermal efficiency compared with structural steel. Key factors contributing to the bearing's failure included high tightening axial force, vibration, and temperature, with spalling and wear as the dominant modes of failure. The improvement in performance further came through dimensional changes reducing stress and deformation. The whole research highlights the need for attention to material selection and axial force control while designing roller bearings to be reliable and efficient. Findings of the present study may thus advocate for the use of AISI 52100 alloy steel in applications requiring high performance and durability. Future studies might look at advanced materials and optimized designs to further advance bearing reliability under demanding conditions.

Comparative study on the drying mechanisms and characteristic changes of fabrics according to heat transfer principles

Microwave-convection (MWC) drying was compared with hot air-convection (HAC) drying to elucidate the differences in the drying characteristics of fabrics based on the moisture type and drying performance. For a single fabric, free water removal was more effective with MWC drying, whereas HAC drying was better suited for bound water removal. For stacked fabrics, the moisture leveling effect of MWC drying enabled a uniform drying of the fabric, evaporating both free water and bound water. The dimensional change of MWC was lower than that of HAC, and the toughness and fiber morphology of the fabrics dried using MWC were comparable to those of untreated fabrics. Furthermore, MWC drying exhibited a higher energy efficiency with increasing fabric loads. The lower drying performance of HAC drying was attributed to the convection of hot air and the limitation of heat conduction. The findings of this study are expected to help develop automatic drying algorithms for household dryers.

A Study on the Differences in Optimized Inputs of Various Data-Driven Methods for Battery Capacity Prediction

As lithium-ion batteries become increasingly popular worldwide, accurately determining their capacity is crucial for various devices that rely on them. Numerous data-driven methods have been applied to evaluate battery-related parameters. In the application of these methods, input features play a critical role. Most researchers often use the same input features to compare the performance of various neural network models. However, because most models are regarded as black-box models, different methods may show different dependencies on specific features given the inherent differences in their internal structures. And the corresponding optimal inputs of different neural network models should be different. Therefore, comparing the differences in optimized input features for different neural networks is essential. This paper extracts 11 types of lithium battery-related health features, and experiments are conducted on two traditional machine learning networks and three advanced deep learning networks in three aspects of input differences. The experiment aims to systematically evaluate how changes in health feature types, dimensions, and data volume affect the performance of different methods and find the optimal input for each method. The results demonstrate that each network has its own optimal input in the aspects of health feature types, dimensions, and data volume. Moreover, under the premise of obtaining more accurate prediction accuracy, different networks have different requirements for input data. Therefore, in the process of using different types of neural networks for battery capacity prediction, it is very important to determine the type, dimension, and number of input health features according to the structure, category, and actual application requirements of the network. Different inputs will lead to larger differences in results. The optimization degree of mean absolute error (MAE) can be improved by 10–50%, and other indicators can also be optimized to varying degrees. Therefore, it is very important to optimize the network in a targeted manner.

Screen time exposure and executive functions in preschool children

Increased screen time (ST) among preschool children is becoming a matter of concern globally. Although gadgets such as phones, tablets and computers might be of educational use in this population, excessive ST might impair cognitive function among preschoolers. As data on this topic in preschool children are scarce, this study sought to investigate the relationship between ST and executive functions (EFs) in this population. A total of 1016 preschool children aged 5–6 years (M = 70.8 months, SD = 4.5) were tested using the Developmental Neuropsychological Assessment (NEPSY-II) and the Dimensional Change Card Sort tests for cognitive flexibility (CF), visual working memory (WM), verbal WM, inhibition and motor persistence with parental consent, while ST was reported via a questionnaire completed by their mothers. Participants spent approximately 2 h in both active and passive ST per day, with boys spending much more time in active ST than girls. There was a very weak negative correlation between CF and both active and passive ST, and a weak negative correlation between verbal WM and both active and passive ST. Additionally, there was a very weak negative correlation between inhibition and passive ST on weekday. To ensure proper development of EFs in preschool children, ST should be limited to ≤ 1 h per day of high-quality educational/interactive content as previously determined by eminent pediatric institutions worldwide. Proven remedies that enhance EFs in children, such as physical activity and cognitive training, should be practiced regularly.

Impact of vial quality on interactions, particle formation, container closure integrity, and gas permeability for frozen drug product storage.

The frozen storage of biopharmaceuticals brings new challenges to the primary packaging material. Due to an increasing demand and the downsides of standard type I glass vials, such as vial breakage, novel vial types for special applications of parenteral drug products have been introduced to the market in the past years. Mechanical stresses due to dimensional changes experienced during freezing and thawing could change the material properties, hence affecting the interaction with the drug product stored in the vial or functionality such as overall integrity. Therefore, we studied the suitability of different vial qualities related to the thermally induced mechanical stresses experienced during frozen drug product preparation and storage. First, the possible failure modes for each vial type were identified. The interaction between vial surface and drug product were investigated considering surface hydrophobicity, surface free energy and surface roughness as well as microscopically visible changes analyzed by confocal laser scanning microscopy. Differences in surface hydrophobicity, roughness and surface free energy between the vial types did not impact the performance upon freeze-thaw stress and did not change with the stress. Screening the vial content for particles originating from the container using light and electron scanning microscopy combined with energy-dispersive X-ray spectroscopy showed only rare cases of particles in coated glass vials. Under extreme stress conditions, including a drop-test in the frozen state, a low number of particles was also detected in coated polymer vials. No quality issues regarding the functionality were observed upon container closure integrity testing, while the oxygen permeability was slightly increased for uncoated and especially coated polymer vials. Overall, the results show that several vial types are appropriate for the frozen storage of drug products and selection should be based on the formulation and other product requirements.

Dimensional Accuracy of Polyether Elastomeric Impression Materials After Using Chitosan as a Disinfectant: A Sustainable Approach to Dental Infection Control

Dimensional Accuracy of Polyether Elastomeric Impression Materials After Using Chitosan as a Disinfectant: A Sustainable Approach to Dental Infection Control

Probing the Neurodynamic Mechanisms of Cognitive Flexibility in Depressed Individuals with Autism Spectrum Disorder.

Introduction: Autism spectrum disorder (ASD) is characterized by deficits in social behavior and executive function (EF), particularly in cognitive flexibility. Whether transcranial magnetic stimulation (TMS) can improve cognitive outcomes in patients with ASD remains an open question. We examined the acute effects of prefrontal TMS on cortical excitability and fluid cognition in individuals with ASD who underwent TMS for refractory major depression. Methods: We analyzed data from an open-label pilot study involving nine participants with ASD and treatment-resistant depression who received 30 sessions of accelerated theta burst stimulation of the dorsolateral prefrontal cortex, either unilaterally or bilaterally. Electroencephalography data were collected at baseline and 1, 4, and 12-weeks posttreatment and analyzed using a mixed-effects linear model to assess changes in regional cortical excitability using three models of spectral parametrization. Fluid cognition was measured using the National Institutes of Health Toolbox Cognitive Battery. Results: Prefrontal TMS led to a decrease in prefrontal cortical excitability and an increase in right temporoparietal excitability, as measured using spectral exponent analysis. This was associated with a significant improvement in the NIH Toolbox Fluid Cognition Composite score and the Dimensional Change Card Sort subtest from baseline to 12 weeks posttreatment (t = 3.79, p = 0.005, n = 9). Improvement in depressive symptomatology was significant (HDRS-17, F (3, 21) = 28.49, p < 0.001) and there was a significant correlation between cognitive improvement at week 4 and improvement in depression at week 12 (r = 0.71, p = 0.05). Conclusion: These findings link reduced prefrontal excitability in patients with ASD and improvements in cognitive flexibility. The degree to which these mechanisms can be generalized to ASD populations without Major Depressive Disorder remains a compelling question for future research.

Evaluation of the Effect of Unilateral Cleft Palate on Piriform Aperture Dimensions.

The aim of the present research was to assess and compare the piriform aperture dimensions of subjects with a unilateral cleft lip and palate (UCLP) and those of a control group using cone-beam computed tomography (CBCT). CBCT data of 40 subjects with a complete UCLP (28 males and 12 females, with a mean age of 17.21 ± 5.75 years) and 40 CBCT images of age- and sex-matched subjects with no cleft, serving as the control group (28 males, 12 females; mean age, 17.25 ± 5.74 years) were included in the study. The maximal height and width of the piriform aperture as well as nasal bone height were measured and statistically compared between the groups. There were no significant differences in the age and sex distributions between the groups. The mean piriform aperture height was significantly lower in the UCLP group than in the control group, while the mean piriform aperture width was significantly higher in the UCLP group compared to the control group (P < .01). Furthermore, the mean bony nasal height was found to be significantly lower in the UCLP group than in the control group (P < .01). According to the present findings, UCLP is associated with changes in the piriform aperture dimensions due to lower height and higher width values. These structural alterations may contribute to the functional and aesthetic nasal challenges in patients with UCLP.

Can Viewing Modality Affect Frontal Mandibular Bone Height Measurement? A Comparison Between 3D Digital Imaging and Communications in Medicine Viewer and Printed Portable Document Format Cone Beam Computer Tomography Reports

Objectives: Buccal cortical bone dimensions are crucial in dental radiology, as they impact orthodontic treatment outcomes. Changes in alveolar bone dimensions can result in malocclusion and require interdisciplinary approaches for correction. The accurate quantification of buccal bone dimensions is crucial for appropriate treatment planning and avoiding medico-legal issues. This study aimed to compare buccal bone height measurements between three-dimensional (3D) digital imaging and communications in medicine (DICOM) data and portable document format (PDF) cone beam computer topography reports for mandibular frontal teeth, testing the hypothesis of no difference in values between the two modalities. Methods: Each of the five observers performed a total of 720 height measurements (360 by DICOM and 360 by PDF), yielding a total of 3600 measurements overall. Results: Compared with the DICOM format, using PDF files was associated with a significantly greater rate of inability to carry out the measurements (8.8% vs. 3%, respectively, p &lt; 0.001, chi-square). The average buccal bone height measured in the DICOM was 11.51 mm, which was significantly greater than the 10.35 mm measured in the PDF (p &lt; 0.001). The mean height measured by the DICOM was consistently greater than that measured by the PDF, with highly significant differences in the findings of four of the examiners (p &lt; 0.001). Conclusions: Viewing modality significantly affected the height of the buccal bone in the frontal mandibular area. Compared with the generated PDF reports, the 3D DICOM viewer performed better than the printed PDF and enabled more measurements in the target area.

Cephalometric evaluation of sagittal and vertical dimension changes after mini-screws assisted rapid palatal expansion: A case series study

Cephalometric evaluation of sagittal and vertical dimension changes after mini-screws assisted rapid palatal expansion: A case series study

Study on the scale effect and mechanical properties of gravel materials in riverbed cover layers

To address the challenges of performing in-situ tests on riverbed overburden gravel, this study employs three scaling methods—equal mass substitution, similar gradation, and the mixed method—to investigate the original gradation of the gravel. Large-scale triaxial consolidated drained shear tests were conducted to evaluate the effects of the maximum particle size reduction ratio (M) and confining pressure on the stress–strain behavior, fractal dimension, particle breakage, and the parameters of the Duncan-Chang model (an elastic model describing nonlinear stress-strain relationships). The study explores how scaling, based on fractal dimension and particle breakage rate, impacts the strength and deformation characteristics of gravel materials. The results show that increasing confining pressure typically leads to higher material strength. As confining pressure increases, particle breakage becomes more pronounced across the various scaling methods. Gravel processed using the similar gradation method exhibited the highest strength, the smallest change in fractal dimension, and the lowest breakage rate, followed by the mixed method. Furthermore, as the M value increases, peak stress also rises, with the modulus coefficient (k) and bulk modulus coefficient (Kb) in the Duncan-Chang model increasing by 4.5 times and 3.3 times, respectively, for M = 15 compared to M = 0. A clear relationship was observed between the change in fractal dimension before and after testing and the breakage index (Bg). As the M value increases, both the difference in fractal dimension and the breakage rate decrease, suggesting that larger M values lead to reduced particle breakage and improved mechanical stability.

Применение цифровых и настольных игр в целях когнитивного развития дошкольников: рекомендации педагогам и родителям

&lt;p&gt;&lt;strong&gt;Introduction.&lt;/strong&gt; The article presents the results of the project &amp;laquo;The Influence of Digital Activity on the Development of Cognitive Functions in Preschool Age&amp;raquo;. &lt;strong&gt;Sample and methods.&lt;/strong&gt; The study was conducted from February to May 2024 with the participation of 88 children from preparatory groups of kinder gardens in Moscow. The following methods were used: the &amp;laquo;Dimensional Change Card Sort&amp;raquo; method (P.D. Zelazo), the &amp;laquo;Memorizing 10 Words&amp;raquo; method (A.R. Luria), and the &amp;laquo;Raven's Coloured Progressive Matrices&amp;raquo;. &lt;strong&gt;Results.&lt;/strong&gt; It was proven that the digital versions of the games &amp;laquo;Dobble&amp;raquo; and &amp;laquo;Tangram&amp;raquo; have a greater positive impact on the development of auditory short-term and long-term memory than the traditional board versions. Girls demonstrated better reproduction scores on the auditory memory test compared to boys. Additionally, a direct link was found between abstract intelligence and the level of cognitive flexibility development. The obtained data are of interest to psychologists, educators, and parents when planning and conducting educational and play activities.&lt;/p&gt;

RATIONALE FOR THE TECHNOLOGICAL PROCESS OF RESTORATION OF WORKING SURFACES OF JOININGS OF ROLLING BEARINGS

The article examines the processes that occur during the operation of the mating surfaces of machine parts, and analyzes the factors that influence their operational characteristics. Zokrema, the specificity of the vicorization of polymer materials in the process of updating the seating shafts and housings under the forging rollers was observed. The completeness of the separation of technological processes aimed at increasing the wear resistance of the working surfaces of these parts has been demonstrated. Theoretical dimensions are presented that allow one to determine the basic parameters of the repeated bending of shafts, housings and rollers by rolling ways to compensate for changes in geometric dimensions of the surface after operation. It is indicated that the durability of the work depends to a large extent on ensuring the inviolability of the roller rings, which includes their checking. For this purpose, the necessary tensions at the landings, plastic deformation of micro-irregularities on the surface of the parts have been ensured, and methods of wear compensation have been introduced. The advantages of the use of polymer materials, which are characterized by high physical and mechanical strength, in technological processes of folding and updating parts have been analyzed. The use of polymer compositions makes it possible to reduce the wear on the surface of parts and their surfaces, such as reducing rubbing, as well as increasing the development of fretting corrosion. Protective, polymer coatings perform the function of microshock absorbers, reducing stress in contact areas and increasing the durability of working surfaces. The problem of choosing the optimal type of polymer materials and the maximum permissible gap and tension in the couplings, which will ensure the unbreakability of the rings and durability before they are tested, is carefully examined. The robot has identified the main directions of further investigations, regardless of the importance of the power of polymer materials, which will ensure the greatest durability of the device during different types of use. The research results indicate the promise of high-quality polymer materials for increasing the wear resistance of working surfaces and extending the service life of robotic machines and equipment.

Poly-Ether-Ether-Ketone (PEEK) Removable Partial Dentures: A Scoping Review

This scoping review aims to comprehensively assess the existing evidence from both clinical and in vitro studies concerning removable partial dentures (RPD) made from poly-ether-ether-ketone (PEEK) to identify current research gaps and enhance the understanding of PEEK’s viability as a material for RPD. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews was applied. A search was made using PubMed, Web of Science, Elsevier’s Scopus, ProQuest and Springer Link databases for articles in the English language up to November 2023, focusing on case reports, clinical, and in vitro studies. A total of 33 studies were included in the analysis, which consisted of 4 case reports, 6 clinical studies, and 23 in vitro studies. Clinical studies predominantly examined patient satisfaction post-PEEK RPD insertion, framework accuracy, dimensional changes in residual ridges, and fungal/bacterial adhesion to PEEK. In vitro studies emphasised retentive force clasps (12 studies), accuracy and fitness (5 studies), material staining effects (3 studies), and diverse surface treatments (3 studies). The current body of evidence reveals a scarcity of clinical studies investigating PEEK as an RPD framework. In vitro studies primarily focused on assessing material retentive forces, with limited attention given to accuracy, surface treatment, and staining of denture base materials. Future research should address these gaps, exploring aspects such as adhesion and biofilm formation (e.g. Candida albicans) on RPD surfaces. Rigorous, well-designed clinical trials and expanded in vitro investigations are essential to establish PEEK RPD as definitive prostheses for partially edentulous patients.

Pre-straining effect on ferrite/pearlite anisotropic transformation strain in steels

The effect of pre-straining on ferrite/pearlite phase transformation in high strength steels is investigated. Two steels differing mainly in their Nb content (0.03C 0.68Si 1.82Mn 0.00 or 0.04Nb in mass%) are either pre-tensioned or pre-compressed and the same-directional transformation strain is measured. A crystal plasticity fast Fourier transform numerical model with back stress effect is used for further investigation and the results are compared. Experimentally, it was found that 30% pre-tension reduces the transformation strain in the same direction by 0.09% (0.00Nb) and 0.13% (0.04Nb), while 30% pre-compression increases it by 0.16% (0.00Nb) and 0.02% (0.04Nb). The numerical simulation estimates the experimentally observed anisotropic transformation strain. In the numerical simulation, even though the anisotropy in transformation plasticity has been qualitatively reproduced, a larger anisotropy effect was observed. The quantitative discrepancies found in between experimental results and numerical results are due to the annihilation of dislocations during the interval between the pre-straining and the onset of phase transformation. The anisotropy in transformation strain found in the experiments is large enough to cause an unacceptable dimensional change in e.g. heat treated steel sheet products.

Transformations in the Ti-6Al-4V Alloy Studied Using Dilatometry Supported by Acoustic Emission.

This paper presents the results of research on the kinetics of transformations in the two-phase (α + β) Ti-6Al-4V alloy. The transformation start and end temperatures during heating at different rates were determined using a dilatometer. A modified dilatometer was employed, equipped with an acoustic emission measurement apparatus and software enabling the assessment of sample dimensional changes during heating and cooling. The results were obtained in the form of dilatometric curves. Additionally, the occurrence of the transformation was confirmed by acoustic emission signals. In the study of the Ti-6Al-4V alloy, acoustic emission refers to the application of this non-destructive technique to monitor the alloy's behavior during thermal processes. As the temperature increased, regardless of the heating rate, the α→β transformation was observed to occur after exceeding 900 °C. Within the transformation range, acoustic emission signals were recorded. Moreover, it was found that the applied research methods enabled the identification of signal components originating from the transformation. The application of acoustic methods in the analysis of phase transformations opens new possibilities for their use in industry.

Analysis of lower-body dimensions and their implementation in compression garment development

This experimental study aims to develop an approach to quantify dimensional changes in the lower body of female football players, with the intention of demonstrating how the results can be used to inform the development of lower body sports compression garments. A framework was established in order to analyse 3D body scans in functional postures using Rhinoceros 3D® and Grasshopper as a response to the limitations of current scanner software. The outcome provides an alternative methodology to locate landmarks on the body and extract dimensions in various sporting postures. Suggestions have been made as to how this information can aid pattern making, sizing, and grading of sports compression leggings, that can provide the wearer with optimal clothing fit, pressure delivery and comfort.

Jaw Growth and Development in Class II Division I Malocclusion Children Using the Myobrace® Muscle Function Appliance.

Class II Division I malocclusion is common in pediatric orthodontics, and is often associated with malocclusion and poor muscle functionality. However, research on post-treatment changes in maxillomandibular dimensions, excluding normal development influences, is limited. Therefore, this study aimed to investigate the effects of Myobrace® appliance and targeted muscle functional training on maxillomandibular dimensions in children with Class II Division I malocclusion, compared to directed oral muscle training alone. This retrospective study included 96 children with Class II Division I malocclusion. Based on the treatment method, the patients were divided into two groups: the treatment group (patients who underwent treatment with the Myobrace® muscle function appliance combined with directed muscle functional training for one year) and the control group (patients who received only directive oral muscle training for one year). The growth changes in jaws in both groups were assessed through X-ray cephalometry and plaster casting. The Sella-Nasion to A point angle (SNA) had increased (p > 0.05), and the maxilla length increased, with significant differences between the two groups (p < 0.05). Furthermore, after intervention, there was a significant increase in mandibular length (p < 0.05). There was a slight decrease in the S-Co value indicating the position of the mandibula. However, this change was not significant, indicating that the mandibula didn't move forward after treatment. The angle between the Frankfort Horizontal Plane and mandibular planes (MP-FH) increased after treatment (p > 0.05), and there were increasing trends on the Y axis, posterior heights, and anterior heights, and these changes were statistically significant (p < 0.05). Additionally, we observed a significant increase in the dental arch (p < 0.05) in the treatment group compared to the control group. This finding suggested that the Myobrace® appliance can promote dental arch growth. Myobrace® appliance effectively boosts dental arch growth while correcting Class II Division I malocclusion. However, it may be limited in cases of Class II Division I with high-angle, maxillary protrusion, or severe mandibular retrusion, emphasizing the significance of assessing patient characteristics to ensure optimal improvement.