Maps of 3D parameters for worn surfaces of composites PA and glass beads sliding on steel

2017 ◽  
Vol 69 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Catalin Pirvu ◽  
Laura Maftei ◽  
Constantin Georgescu ◽  
Lorena Deleanu
Keyword(s):  
Surface Quality ◽  
Glass Bead ◽  
Three Dimensional ◽  
Glass Beads ◽  
Mean Deviation ◽  
Content Type ◽  
3D Texture ◽  
Texture Parameters ◽  
Before And After ◽  
Worn Surfaces

Purpose This paper aims to present the influence of glass bead concentration in a matrix of polyamide on wear and several three-dimensional (3D) parameters of the surface texture when the composite is sliding on steel in dry contact. Design/methodology/approach There were mold disks with the following concentrations in glass beads: 2.5, 5.0, 10, 20, 30 and 50 per cent. The mix of glass beads has diameters in the range of several microns to 50 microns. Tests were done on a pin-on-disk tribotester, in dry regime, for the following parameters: average pressure (1, 2 and 3 MPa) and sliding speed (0.5, 1.0 and 1.5 m/s). Zones of 500 × 500 μm were investigated from worn tracks generated on the composite disks, and the average values of several 3D texture parameters were analyzed. Findings The authors plotted maps indicating no correlation between the glass bead concentration and the parameters characterizing the surface quality (amplitude parameters and functional parameters). Composites with concentrations of 10[…]30 per cent glass beads generated worn surfaces with better quality as compared to composites with extreme concentrations: low (2.5 and 5 per cent) and high (50 per cent). Practical implications This set of parameters allows for evaluating the influence of regime parameters on the surface quality, by comparing the obtained values before and after sliding, and this evolution of roughness parameters could give recommendations for selecting the friction couple of materials for particular contacts that function with repeated starts and stops. Originality/value The results encourage the researchers to use a set of 3D texture parameters instead of “classical” two-dimensional parameters, the arithmetic mean deviation of the profile, Ra, because this set of parameters better evaluate the surface quality, especially for worn surfaces.

3D texture parameters for wear scars after severe regime

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lorena Deleanu ◽  
Traian Florian Ionescu ◽  
George Catalin Cristea ◽  
Cornel Camil Suciu ◽  
Constantin Georgescu
Keyword(s):  
Rapeseed Oil ◽  
Wear Scar ◽  
Roughness Parameters ◽  
Wear Scar Diameter ◽  
Content Type ◽  
Functional Parameters ◽  
3D Texture ◽  
Texture Parameters ◽  
Practical Implications ◽  
Worn Surfaces

Purpose This paper aims to present an analysis of several 3 D texture parameters for the entire wear scars obtained in severe regime, on a four-ball tester. The aim of this analysis is to correlate the tribological parameter as wear scar diameter to texture parameters. Design/methodology/approach Tested lubricants were rapeseed oil, rapeseed oil additivated with 1% Wt nano TiO2 and rapeseed oil additivated with 1%Wt nano ZnO. The severe regime was applied for 1400 rpm and for loads increasing in steps of 50 N, from 500 to 900 N. Several analyzed roughness parameters (height parameters and functional ones) could be related to the evolution of a wear parameter, the wear scar diameter. Comparing the values for neat rapeseed oil and additivated variants, the texture parameters allow for evaluating if the additives protect or not the worn surfaces. Findings Measurements pointed out two groups of roughness parameters: one that has an evolution depending on wear scar diameter (WSD) and load (Sa, St, functional parameters) and one including Ssk that has shown no dependence on load and WSD. Also, the functional parameters Spk and Svk follow in a similar manner the wear parameter, WSD, but Sk is the least dependent on load. For the highest load, amplitude parameters such as Sa and St are following the tendency of WSD. Each lubricant has its particular correlation between wear parameters and texture quality, expressed by the help of a set of roughness parameters. Research limitations/implications Such studies help tribologists to rank lubricants based on a combined analysis with wear parameters and texture parameters. Practical implications The results allow for evaluating new formulated lubricants. Originality/value The study on the quality on worn surfaces introduces the original idea of analyzing the entire wear scar surface (approximated by an ellipse with the axes as those experimentally measured) by the help of a set of 3 D roughness parameters.

Experimental study on the accuracy and surface quality of printed versus machined holes in PEI Ultem 9085 FDM specimens

2021 ◽  
Vol 27 (11) ◽  
pp. 1-12
Author(s):  
Giovanni Gómez-Gras ◽  
Marco A. Pérez ◽  
Jorge Fábregas-Moreno ◽  
Guillermo Reyes-Pozo
Keyword(s):  
Surface Quality ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Technological Parameters ◽  
Content Type ◽  
Fused Deposition ◽  
Comparison Of The Results ◽  
Through Hole

Purpose This paper aims to investigate the quality of printed surfaces and manufacturing tolerances by comparing the cylindrical cavities machined in parts obtained by fused deposition modeling (FDM) with the holes manufactured during the printing process itself. The comparison focuses on the results of roughness and tolerances, intending to obtain practical references when making assemblies. Design/methodology/approach The experimental approach focuses on the comparison of the results of roughness and tolerances of two manufacturing strategies: geometric volumes with a through-hole and the through-hole machined in volumes that were initially printed without the hole. Throughout the study, both alternates are explained to make appropriate recommendations. Findings The study shows the best combinations of technological parameters, both machining and three-dimensional printing, which have been decisive for obtaining successful results. These conclusive results allow enunciating recommendations for use in the industrial environment. Originality/value This paper fulfills an identified need to study the dimensional accuracy of the geometries obtained by additive manufacturing, as no experimental evidence has been found of studies that directly address the problem of the FDM-printed part with geometric and dimensional tolerances and desirable surface quality for assembly.

Changes in morphology and optical properties of polyvinyl alcohol foils induced by Congo red dye concentration and stretching degree

2014 ◽  
Vol 34 (4) ◽  
pp. 345-351 ◽  
Author(s):  
Carmen Beatrice Zelinschi ◽  
Iuliana Stoica ◽  
Dana Ortansa Dorohoi
Keyword(s):  
Optical Properties ◽  
Polyvinyl Alcohol ◽  
Congo Red ◽  
Order Parameter ◽  
Three Dimensional ◽  
Morphological Properties ◽  
Degree Of Crystallinity ◽  
Texture Parameters ◽  
Before And After ◽  
Red Dye

Abstract To establish correlations between the optical and morphological properties of anisotropic polyvinyl alcohol (PVA) foils containing Congo red (CR) dye in various concentrations, characteristics such as degree of crystallinity, dichroic ratio, order parameter, birefringence, surface morphology, and three-dimensional texture parameters were estimated before and after stretching. An increase in morphological and optical anisotropy with the degree of stretching has been evidenced for both pure and CR-containing PVA foils, this behavior being facilitated by the presence of the dye. The study of these properties lays the foundation for understanding the circumstances in which PVA foils containing CR can be used as polarizing filters.

The dyeability and after-dyeing wearability of TPU-based 3D-printed fabrics

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhaoling Sun ◽  
Jiaguang Meng ◽  
Yanning Yang ◽  
Lingjie Yu ◽  
Chao Zhi
Keyword(s):  
Fused Deposition Modeling ◽  
Orthogonal Experiment ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Bending Rigidity ◽  
Content Type ◽  
Fused Deposition ◽  
Dyeing Process ◽  
Before And After ◽  
Dyeing Method

PurposeThe purpose of the paper is to study the dyeing process of three-dimensional-printed (3DP) fabrics, and then study the wearability of the fabrics before and after dyeing to provide a feasible dyeing method of 3DP clothes.Design/methodology/approachIn this regard, the thermoplastic polyurethane (TPU) was applied during the process of 3DP. Then, the imitation twill weave (ITW) was printed with fused deposition modeling (FDM) technology using TPU and the suspension of Disperse Blue 2BLN (as a dye) was prepared. After that, the single factor analysis and orthogonal experiment of dyeing were combined to obtain the optimized dyeing process. And then, ITW fabrics were dyed through the weak acid-low temperature dyeing method. In the end, in order to discuss the wearability of ITW fabrics, the dyeing experiments, including permeability, wrinkle recovery angle, bending rigidity, crock fastness and washing colorfastness were carried out.FindingsThe surface morphology of TPU before and after spinning was established by field emission scanning electron microscopy (FE-SEM), which was confirmed the surface of TPU getting smoother after spinning. The wearability of the fabric after dyeing was not affected compared with before dyeing. Moreover, both colorfastness grades were above 4–5 with high colorfastness.Originality/valueThe article provides a method for 3DP dyeing, which can solve the problem of a single color. And the wearability demonstrates that 3DP fabrics after dyeing-based TPU have more value for clothing than before dyeing.

A novel adaptive slicing algorithm based on ameliorative area ratio and accurate cusp height for 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yifei Hu ◽  
Xin Jiang ◽  
Guanying Huo ◽  
Cheng Su ◽  
Hexiong Li ◽  
...  
Keyword(s):  
3D Printing ◽  
Surface Quality ◽  
Three Dimensional ◽  
Geometric Error ◽  
Area Ratio ◽  
Adaptive Slicing ◽  
Content Type ◽  
Contour Matching ◽  
Slicing Method ◽  
Cusp Height

Purpose Adaptive slicing is a key step in three-dimensional (3D) printing as it is closely related to the building time and the surface quality. This study aims to develop a novel adaptive slicing method based on ameliorative area ratio and accurate cusp height for 3D printing using stereolithography (STL) models. Design/methodology/approach The proposed method consists of two stages. In the first stage, the STL model is sliced with constant layer thickness, where an improved algorithm for generating active triangular patches, the list is developed to preprocess the model faster. In the second stage, the model is first divided into several blocks according to the number of contours, then an axis-aligned bounding box-based contour matching algorithm and a polygons intersection algorithm are given to compare the geometric information between several successive layers, which will determine whether these layers can be merged to one. Findings Several benchmarks are applied to verify this new method. Developed method has also been compared with the uniform slicing method and two existing adaptive slicing methods to demonstrate its effectiveness in slicing. Originality/value Compared with other methods, the method leads to fewer layers whilst keeping the geometric error within a given threshold. It demonstrates that the proposed slicing method can reach a trade-off between the building time and the surface quality.

Effects of ligation and embolization on Kf and multiple tracer measurements in dog lungs

1990 ◽  
Vol 69 (4) ◽  
pp. 1460-1466 ◽  
Author(s):  
J. D. Bradley ◽  
R. E. Parker ◽  
T. R. Harris ◽  
K. A. Overholser
Keyword(s):  
Surface Area ◽  
Glass Bead ◽  
Glass Beads ◽  
Lung Weight ◽  
Capillary Filtration ◽  
Permeability Surface ◽  
Capillary Filtration Coefficient ◽  
Before And After ◽  
Filtration Area ◽  
Area Product

In isolated blood-perfused dog lungs, the capillary filtration coefficient (Kf) and the permeability-surface area product of urea (PS) were measured to determine their responses to two different methods of altering filtration area: lobe ligation (LL, n = 5) and glass bead embolization (GBE, n = 4) during constant perfusion rates (700 +/- 45 ml/min). When two of three lobes were ligated, Kf decreased (1.36 +/- 0.13 to 0.58 +/- 0.23 g.min-1.cmH2O-1; P less than 0.05), but PS did not change (2.02 +/- 0.4 to 1.71 +/- 0.3 ml/s). Kf per gram of perfused blood-free dry lung weight was unchanged by LL (0.051 +/- 0.17 to 0.052 +/- 0.18 g.min-1.cmH2O-1), indicating that surface area per gram measured by Kf remained the same. However, PS per gram dry lung doubled (0.07 +/- 0.016 to 0.146 +/- 0.06 ml/s; P less than 0.05) after LL, suggesting that recruitment occurred in the remaining lobe. When three lobes were embolized with 200-microns glass beads (0.48 +/- 0.01 g beads/kg body wt), PS decreased (2.1 +/- 0.22 to 0.94 +/- 0.09 ml/s; P less than 0.05), but Kf was not altered (1.01 +/- 0.17 to 1.04 +/- 0.18 g.min-1.cmH2O-1). The constancy of Kf after GBE implies that the vascular pressure increase during the Kf measurement was transmitted to both blocked and flowing vessels and thereby measured the same filtration area before and after GBE. PS decreased significantly after GBE because of a loss of perfused surface area by the beads blocking flow in small arterial vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Guided surgery with 3D printed device: a case report

2020 ◽  
Author(s):  
Michelle Carvalho de Sales ◽  
Rafael Maluza Flores ◽  
Julianny da Silva Guimaraes ◽  
Gustavo Vargas da Silva Salomao ◽  
Tamara Kerber Tedesco ◽  
...  
Keyword(s):  
Operating Time ◽  
Three Dimensional ◽  
Conventional Technique ◽  
Cervical Region ◽  
Mean Deviation ◽  
Apical Region ◽  
Virtual Planning ◽  
Surgical Guide ◽  
Surgical Guides ◽  
High Level

Dental surgeons need in-depth knowledge of the bone tissue status and gingival morphology of atrophic maxillae. The aim of this study is to describe preoperative virtual planning of placement of five implants and to compare the plan with the actual surgical results. Three-dimensional planning of rehabilitation using software programs enables surgical guides to be specially designed for the implant site and manufactured using 3D printing. A patient with five teeth missing was selected for this study. The patient’s maxillary region was scanned with CBCT and a cast model was produced. After virtual planning using ImplantViewer, five implants were placed using a printed surgical guide. Two weeks after the surgical procedure, the patient underwent another CBCT scan of the maxilla. Statistically significant differences were detected between the virtually planned positions and the actual positions of the implants, with a mean deviation of 0.36 mm in the cervical region and 0.7 mm in the apical region. The surgical technique used enables more accurate procedures when compared to the conventional technique. Implants can be better positioned, with a high level of predictability, reducing both operating time and patient discomfort.

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 90-92 ◽  
Author(s):  
Mark E. Linskey
Keyword(s):  
Gamma Knife ◽  
Stereotactic Radiotherapy ◽  
Three Dimensional ◽  
Late Recurrence ◽  
Vestibular Schwannomas ◽  
Tumor Control ◽  
Complication Rates ◽  
Content Type ◽  
Single Fraction ◽  
Fine Print

✓ By definition, the term “radiosurgery” refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed “stereotactic radiotherapy.” There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image—targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS “halo effect.” It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.

Study on the Glass Beads Refractive Index Testing Technology

2012 ◽  
Vol 487 ◽  
pp. 805-809
Author(s):  
Jun Ma ◽  
Dong Hua Guo
Keyword(s):  
Refractive Index ◽  
Glass Bead ◽  
Glass Beads ◽  
Research Trend ◽  
Future Research ◽  
The Future ◽  
Testing Technology ◽  
At Home

this thesis discusses the main testing technologies at home and abroad relating to the glass bead refractive index, analyses the research emphases relating to the glass bead refractive index testing technology at present and point out the future research trend.

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