Cranial reconstruction using prefabricated direct 3DP porous polyethylene

2019 ◽  
Vol 26 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Pataravit Rukskul ◽  
Waraporn Suvannapruk ◽  
Jintamai Suwanprateeb
Keyword(s):  
Three Dimensional ◽  
Ct Scanning ◽  
Porous Polyethylene ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Long Term Stability ◽  
Aesthetic Results ◽  
Ct Evaluation ◽  
Infection Resistance ◽  
Porous Polyethylene Implants

Purpose The purpose of this study is to evaluate the intra- and post-operative performance and safety of direct three dimensional printing (3DP) porous polyethylene implants in cranial reconstruction. Design/methodology/approach Prefabricated porous polyethylene implants were prepared by direct 3DP, and cranioplasty implantation was performed. Postoperative aesthetics, patient satisfaction, firmness of the implant, reactions to the implant and 3D computed tomography (CT) scanning were assessed after 2, 6, 12 and 24 months postoperatively. Findings No complications after surgery were encountered. Excellent aesthetic results were obtained in all cases, and all the patients were satisfied with the reconstruction outcome. Bone density structure was found to ingrowth into these direct 3DP porous polyethylene implants and the content increased with increasing follow-up times. Research limitations/implications This study was a pilot study conducted in a single group and evaluated in a short-term period. The bone formation and ingrowth were indirectly assessed by 3D CT evaluation. Originality/value This work reported the use and evaluation of direct 3DP porous polyethylene in middle- to large-sized cranial reconstructions. It evidently showed the bonding of implants to surrounding tissues which would result in the long-term stability and infection resistance of the implant.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

2020 ◽  
Vol 16 (8) ◽  
pp. 967-977
Author(s):  
Zhonghua Sun
Keyword(s):  
Cardiovascular Disease ◽  
Cardiac Computed Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Aortic Diseases ◽  
Clinical Value ◽  
Three Dimensional Printing ◽  
Doctor Patient Communication ◽  
Medical Education And Training ◽  
3D Printed

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

Additive manufactured multi-material structure with directional specific mechanical properties based upon classical lamination theory

2018 ◽  
Vol 24 (7) ◽  
pp. 1212-1220 ◽  
Author(s):  
Sugavaneswaran M. ◽  
Arumaikkannu G.
Keyword(s):  
Mechanical Properties ◽  
Three Dimensional ◽  
Additive Manufacture ◽  
Material Structure ◽  
Loading Conditions ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Classical Lamination Theory ◽  
Innovative Methodology ◽  
Lamination Theory

Purpose This paper aims to additive manufacture (AM) the multi-material (MM) structure with directional-specific mechanical properties based on the classical lamination theory of composite materials. Design/methodology/approach The polyjet three-dimensional printing (3DP) process is used to fabricate the MM structure with directional-specific mechanical properties. MMs within a layer are positioned and oriented based on the classical lamination theory to achieve directional-specific properties. Mechanical behavior of the AM structure was examined under various loading conditions to justify the directional-specific properties. Findings With MM processing capabilities of the polyjet 3DP machine, AM MM structures with directional-specific mechanical properties were fabricated. From experimentation, it was observed that the AM MM structure with a quasi-isotropic laminate has superior tensile and flexural strength, and the AM MM structure with an angle ply laminate has superior shear strength. Various mechanical properties determined through testing will be useful for the selection of an appropriate layup arrangement within a structure for appropriate loading conditions. Originality/value This study presents the innovative methodology for the fabrication of AM MM structures with tailor-made mechanical properties. The developed methodology paves way for using the polyjet 3DP MM structure for applications such as the complaint mechanism, snap fits and thin features, which require directional-specific properties.

A three-dimensional shoulder protector based on ergonomics for workers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ran-i Eom ◽  
Yejin Lee
Keyword(s):  
Body Shape ◽  
Three Dimensional ◽  
Health And Safety ◽  
The Body ◽  
Construction Sites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Functional Studies ◽  
Work Posture ◽  
Dimensional Printing

PurposeThe use of shoulder protectors is strongly recommended when carrying objects on the shoulder to ensure the health and safety of workers. Thus, this study aimed to develop and verify an ergonomic shoulder protector that considers human body shape and carrying posture from an ergonomic perspective. Ultimately, this study will present a shoulder protector with enhanced fit and safety for carrying workers at construction sites.Design/methodology/approachThe shoulder protector was designed and printed using three-dimensional printing technology with variable side neck points and shoulder point heights to reflect the human body's shoulder line shape and to position the carried object stably on the shoulder. The developed shoulder protectors were evaluated in terms of their fit according to the work posture of the carrier, adherence upon motion and durability through structural analysis.FindingsThe design of the shoulder protector for carrying workers followed the shoulder line. It is best placed above the side neck point by 1.0 cm and above the shoulder point by 2.0 cm. Its length is slightly shorter than the human shoulder for superior fit and safety.Originality/valueThe final shoulder protector (FSP) for carrying workers reflects the body curvature while enhancing fit and safety by considering activity and protective factors. As functional studies and evaluations on the need for protectors are scarce, this study provides fundamental data in the evaluation of protective gears.

Rapid manufacturing of copper-graphene composites using a novel rapid tooling technique

2020 ◽  
Vol 26 (4) ◽  
pp. 765-776 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak Mohan Pandey
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Rate Coefficient ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Dimensional Printing

Purpose The purpose of this study is to study the mechanical, tribological and electrical properties of the copper-graphene (Cu-Gn) composites fabricated by a novel rapid tooling technique consist of three-dimensional printing and ultrasonic-assisted pressureless sintering (UAPS). Design/methodology/approach Four different Cu-Gn compositions with 0.25, 0.5, 1 and 1.5 per cent of graphene were fabricated using an amalgamation of three-dimensional printing and UAPS. The polymer 3d printed parts were used to prepare mould cavity and later the UAPS process was used to sinter Cu-Gn powder to acquire free-form shape. The density, hardness, wear rate, coefficient of friction and electrical conductivity were evaluated for the different compositions of graphene and compared with the pure copper. Besides, the comparison was performed with the conventional method. Findings Cu-Gn composites revealed excellent wear properties due to higher hardness, and the lubrication provided by the graphene. The electrical conductivity of the fabricated Cu-Gn composites started increasing initially but decreased afterwards with increasing the content of graphene. The UAPS fabricated composites outperformed the conventional method manufactured samples with better properties such as density, hardness, wear rate, coefficient of friction and electrical conductivity due to homogeneous mixing of metal particles and graphene. Originality/value The fabrication of Cu-Gn composite freeform shapes was found to be difficult using conventional methods. The novel technique using a combination of polymer three-dimensional printing and UAPS as rapid tooling was introduced for the fabrication of freeform shapes of Cu-Gn composites and mechanical, tribological and electrical properties were studied. The method can be used to fabricate optimized complex Cu-Gn structures with improved wear and electrical applications.

Three-dimensional computerized tomography angiography in patients with hyperacute intracerebral hemorrhage

1999 ◽  
Vol 91 (3) ◽  
pp. 424-431 ◽  
Author(s):  
Yasuo Murai ◽  
Ryo Takagi ◽  
Yukio Ikeda ◽  
Yasuhiro Yamamoto ◽  
Akira Teramoto
Keyword(s):  
Intracerebral Hemorrhage ◽  
Ct Angiography ◽  
Computerized Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
3D Ct ◽  
Content Type ◽  
Hematoma Enlargement ◽  
3D Ct Angiography ◽  
Fine Print

Object. The authors confirm the usefulness of extravasation detected on three-dimensional computerized tomography (3D-CT) angiography in the diagnosis of continued hemorrhage and establishment of its cause in patients with acute intracerebral hemorrhage (ICH).Methods. Thirty-one patients with acute ICH in whom noncontrast and 3D-CT angiography had been performed within 12 hours of the onset of hemorrhage and in whom conventional cerebral angiographic studies were obtained during the chronic stage were prospectively studied. Noncontrast CT scanning was repeated within 24 hours of the onset of ICH to evaluate hematoma enlargement.Findings indicating extravasation on 3D-CT angiography, including any abnormal area of high density on helical CT scanning, were observed in five patients; three of these demonstrated hematoma enlargement on follow-up CT studies. Thus, specificity was 60% (three correct predictions among five positives) and sensitivity was 100% (19 correct predictions among 19 negatives). Evidence of extravasation on 3D-CT angiography indicates that there is persistent hemorrhage and correlates with enlargement of the hematoma.Regarding the cause of hemorrhage, five cerebral aneurysms were visualized in four patients, and two diagnoses of moyamoya disease and one of unilateral moyamoya phenomenon were made with the aid of 3D-CT angiography. Emergency surgery was performed without conventional angiography in one patient who had an aneurysm, and it was clipped successfully.Conclusions. Overall, 3D-CT angiography was found to be valuable in the diagnosis of the cause of hemorrhage and in the detection of persistent hemorrhage in patients with acute ICH.

A review of 3D concrete printing systems and materials properties: current status and future research prospects

2018 ◽  
Vol 24 (4) ◽  
pp. 784-798 ◽  
Author(s):  
Suvash Chandra Paul ◽  
Gideon P.A.G. van Zijl ◽  
Ming Jen Tan ◽  
Ian Gibson
Keyword(s):  
Three Dimensional ◽  
Current Status ◽  
Future Research ◽  
Structural Elements ◽  
Construction Time ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Materials Research ◽  
Printing System ◽  
Dimensional Printing

Purpose Three-dimensional printing of concrete (3DPC) has a potential for the rapid industrialization of the housing sector, with benefits of reduced construction time due to no formwork requirement, ease of construction of complex geometries, potential high construction quality and reduced waste. Required materials adaption for 3DPC is within reach, as concrete materials technology has reached the point where performance-based specification is possible by specialists. This paper aims to present an overview of the current status of 3DPC for construction, including existing printing methods and material properties required for robustness of 3DPC structures or structural elements. Design/methodology/approach This paper has presented an overview of three categories of 3DPC systems, namely, gantry, robotic and crane systems. Material compositions as well as fresh and hardened properties of mixes currently used for 3DPC have been elaborated. Findings This paper presents an overview of the state of the art of 3DPC systems and materials. Research needs, including reinforcement in the form of bars or fibres in the 3D printable cement-based materials, are also addressed. Originality/value The critical analysis of the 3D concrete printing system and materials described in this review paper is original.

Vendor rating system for an Indian start-up: a combined AHP & TOPSIS approach

2018 ◽  
Vol 22 (3) ◽  
pp. 220-241 ◽  
Author(s):  
Rohit Kumar Singh ◽  
Surendra Kansara ◽  
Niraj Kumar Vishwakarma
Keyword(s):  
Relevant Literature ◽  
Three Dimensional ◽  
Pairwise Comparison ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Start Up ◽  
Order Preference ◽  
Topsis Approach ◽  
Rating Model ◽  
Vendor Rating

Purpose The aim of this paper is to identify the criteria that are used for vendor or supplier rating, prioritize these criteria based on the industry inputs and develop a vendor rating model. The data were collected from an Indian start-up working in product development using three-dimensional printing (3DP). Design/methodology/approach Factors of importance for vendor rating were identified through industry visits, and interacting with the industry experts from the start-up under consideration, substantiated by extensive review of relevant literature. A questionnaire-based survey was carried out to further narrow down the factors important to the industry, prioritizing them with a pairwise comparison analysis as envisaged in the analytical hierarchy process (AHP) technique along with the calculation of consistency ratios. Technique for order preference by similarity to ideal solution (TOPSIS) methodology was further used for data aggregation. Findings This research brought forward the criteria that are useful for rating vendors or suppliers with reference to 3DP sector. Originality/value This paper integrates AHP and TOPSIS to solve a multi-criteria vendor rating problem. The attempt was made to make vendor rating process universal so that it can encompass all the vendors of the firm.

Evaluation and treatment of congenital and developmental anomalies of the cervical spine

2004 ◽  
Vol 1 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Arnold H. Menezes
Keyword(s):  
Cervical Spine ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Growth Potential ◽  
Limb Weakness ◽  
Content Type ◽  
Spinal Stabilization ◽  
Vascular Abnormalities ◽  
The Stability ◽  
High Index Of Suspicion

✓ Congenital and developmental osseous abnormalities of the cervical spine can result in neural compression ranging from the medulla oblongata to the cervicothoracic spinal cord junction. These may present in infancy as scoliosis and even limb weakness. A high index of suspicion is essential. Neurodiagnostic imaging relies on high-resolution computerized tomography (CT) scanning and three-dimensional CT reconstructions as well as magnetic resonance imaging and angiography. The anatomical/physiological CT factors considered when developing a surgical approach are: 1) the stability and reducibility of the lesions; 2) direction and manner of encroachment of the lesion on the neural structures; 3) neural and vascular abnormalities; and 4) growth potential of the affected area. Primary stabilization is required for reducible lesions, whereas irreducible lesions are decompressed in the manner in which encroachment has occurred. Instability, whether present before or after operative intervention, required spinal stabilization. Illustrative examples of this approach are presented.

Three-dimensional angiography for radiosurgical treatment planning for arteriovenous malformations

2003 ◽  
Vol 98 (3) ◽  
pp. 536-543 ◽  
Author(s):  
Federico Colombo ◽  
Carlo Cavedon ◽  
Paolo Francescon ◽  
Leopoldo Casentini ◽  
Umberto Fornezza ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Imaging Modality ◽  
Treatment Plan ◽  
Three Dimensional ◽  
Ct Scanning ◽  
New Method ◽  
Rotational Angiography ◽  
Content Type ◽  
3D Rotational Angiography ◽  
Fine Print

Object. Radiosurgical treatment of a cerebral arteriovenous malformation (AVM) requires the precise definition of the nidus of the lesion in stereotactic space. This cannot be accomplished using simple stereotactic angiography, but requires a combination of stereotactic biplanar angiographic images and stereotactic contrast-enhanced computerized tomography (CT) scans. In the present study the authors describe a method in which three-dimensional (3D) rotational angiography is integrated into stereotactic space to aid treatment planning for radiosurgery. Methods. Twenty patients harboring AVMs underwent treatment planning prior to linear accelerator radiosurgery. Planning involved the acquisition of two different data sets, one of which was obtained using the standard method (a combination of biplanar stereotactic angiography with stereotactic CT scanning), and the other, which was procured using a new technique (nonstereotactic 3D rotational angiography combined with stereotactic CT scanning by a procedure of image fusion). The treatment plan that was developed using the new method was compared with that developed using the standard one. For each patient the number of isocenters and the dimension of selected collimators were the same, based on the information supplied in both methods. Target coordinates were modified in only five cases and by a limited amount (mean 0.7 mm, range 0.3–1 mm). Conclusions. The new imaging modality offers an easier and more immediate interpretation of 3D data, while maintaining the same accuracy in target definition as that provided by the standard technique. Moreover, the new method has the advantage of using nonstereotactic 3D angiography, which can be performed at a different site and a different time with respect to the irradiation procedure.

scholarly journals Remanufacturing of end-of-life glass-fiber reinforced composites via UV-assisted 3D printing

2019 ◽  
Vol 26 (6) ◽  
pp. 981-992
Author(s):  
Andrea Mantelli ◽  
Marinella Levi ◽  
Stefano Turri ◽  
Raffaella Suriano
Keyword(s):  
Mechanical Properties ◽  
Circular Economy ◽  
Three Dimensional ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Glass Fiber Reinforced ◽  
Complex Shapes ◽  
Dimensional Printing

Purpose The purpose of this study is to demonstrate the potential of three-dimensional printing technology for the remanufacturing of end-of-life (EoL) composites. This technology will enable the rapid fabrication of environmentally sustainable structures with complex shapes and good mechanical properties. These three-dimensional printed objects will have several application fields, such as street furniture and urban renewal, thus promoting a circular economy model. Design/methodology/approach For this purpose, a low-cost liquid deposition modeling technology was used to extrude photo-curable and thermally curable composite inks, composed of an acrylate-based resin loaded with different amounts of mechanically recycled glass fiber reinforced composites (GFRCs). Rheological properties of the extruded inks and their printability window and the conversion of cured composites after an ultraviolet light (UV) assisted extrusion were investigated. In addition, tensile properties of composites remanufactured by this UV-assisted technology were studied. Findings A printability window was found for the three-dimensional printable GFRCs inks. The formulation of the composite printable inks was optimized to obtain high quality printed objects with a high content of recycled GFRCs. Tensile tests also showed promising mechanical properties for printed GFRCs obtained with this approach. Originality/value The novelty of this paper consists in the remanufacturing of GFRCs by the three-dimensional printing technology to promote the implementation of a circular economy. This study shows the feasibility of this approach, using mechanically recycled EoL GFRCs, composed of a thermoset polymer matrix, which cannot be melted as in case of thermoplastic-based composites. Objects with complex shapes were three-dimensional printed and presented here as a proof-of-concept.

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