Experimental Investigation Into the Fabrication of Porous Biodegradable Fe Scaffold by Microwave Sintering of 3D Printed Green Body

2021 ◽  
Author(s):  
Dipesh Kumar Mishra ◽  
Pulak Mohan Pandey
Keyword(s):  
Porous Structure ◽  
Microwave Sintering ◽  
Three Dimensional ◽  
The Body ◽  
Compressive Yield Strength ◽  
Electron Microscopic ◽  
Biodegradable Implant ◽  
Three Dimensional Printing ◽  
Sem Image ◽  
Design Structure

Abstract Iron has appealing biodegradable properties that makes compatible for biodegradable implant tools applications. Although, the slow corrosion rate of Fe made obsolete for biomedical applications. The incorporation of the porous structure may result in an enhanced degradation rate. The main advantage offer by the porous structure is to allow to flow the body transportation fluid through it and ease to proliferate the new tissue. Therefore, the current work focused on the development of a porous Fe structures using micro-extrusion based three-dimensional printing (ME3DP) and pressure less microwave sintering. The metallic-based polymeric ink used to fabricate the intent design structure. Subsequently, samples were heated in the microwave sintering furnace. The experimentations were done to evaluate the outcomes of different Fe concentrations (91–95 wt.%) on density and compressive yield strength of developed porous parts. Experimental observation deduced that fabricated part ≥ 94.wt.% of Fe concentration has strong bonding strength between the printed layers. Moreover, the mechanical property of 94 wt.% has found greater than 95 wt.% of Fe concentration. The scanning electron microscopic (SEM) image illustrated the presence of porous morphology into the fabricated body. Additionally, XRD (X-ray diffraction) plots exhibited the purity of sample without any contamination residue.

Rapid manufacturing of biodegradable pure iron scaffold using amalgamation of three-dimensional printing and pressureless microwave sintering

2018 ◽  
Vol 233 (6) ◽  
pp. 1876-1895 ◽  
Author(s):  
Pawan Sharma ◽  
Pulak M Pandey
Keyword(s):  
Yield Strength ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Compressive Yield Strength ◽  
Soaking Time ◽  
Three Dimensional Printing ◽  
Dimensional Printing

In the present work, a rapid tooling process using three-dimensional printing and pressureless microwave sintering has been developed for the fabrication of biodegradable pure iron. Carbonyl iron particles were used for sample preparation and phosphate-based investment material was used for mould fabrication. Cylindrical samples were fabricated successfully using the developed rapid tooling process. The fabrication experiments were planned based on response surface methodology to evaluate the effect of microwave sintering parameters, namely sintering temperature, heating rate and soaking time on sintered density, shrinkage and compressive yield strength. The results showed that sintered density and compressive yield strength increased with the rise in sintering temperature from α to γ iron transformation temperature and were found to decrease with further rise in temperature. The shrinkage was found to increase with the increase in sintering temperature. Moreover, with the increase in soaking time and decrease in heating rate, sintered density, shrinkage and compressive yield strength were found to increase. Scanning electron microscopy and the X-ray diffraction plot of the fabricated iron samples showed that even without the application of pressure proper bonding of carbonyl iron particles was achieved. Mould material contamination or oxidation was not evidenced in the experiments. A multi-objective optimization using genetic algorithm was performed to obtain optimum microwave sintering parameters for maximum sintered density as well as compressive strength and minimum shrinkage. A case study on the fabrication of scaffold for human skull was performed to test the efficacy of the developed rapid tooling process.

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.

Study on Biodegradable Implant with Poly (l-Lactic Acid) and its Releasing Character In Vitro

2011 ◽  
Vol 236-238 ◽  
pp. 2744-2747
Author(s):  
Wei Dong Huang ◽  
Sheng Fang Li ◽  
Tao Zou ◽  
Xian You Xia
Keyword(s):  
Three Dimensional ◽  
Environmental Scanning ◽  
Biodegradable Implant ◽  
Three Dimensional Printing ◽  
Novel Technique ◽  
Single Form ◽  
Conventional Technology ◽  
Dimensional Printing ◽  
Scanning Electron

To elucidate the effects of implants fabricated by three-dimensional printing (3DP) technologies, a novel technique enables the complex implant release profiles, precise dosage control and rapid formulation in a single form. In this study, a unique implant with polylactic acid-based polymer powders was developed by the process. Test of the morphology and the releasing experiments in vitro of the implants were done to evaluate the implant devices. At about 100-day release of the implants in vitro, the drug concentration was measured and the profiles were made. The morphology of the implants of both technologies was characterized by three dimensional stereoscopy and environmental scanning electron microscope. The release behaviour and the microstructure were detected to compare the effects. 3DP technology allows the design and fabrication of implants with a novel micro- and macro-architecture which cannot be fabricated or may be fabricated with many difficulties in conventional technology.

An assessment of thermosetting infiltrate in powder-based composites made by additive manufacturing

2018 ◽  
Vol 53 (7) ◽  
pp. 873-882 ◽  
Author(s):  
Breno Ferreira Lizardo ◽  
Luciano Machado Gomes Vieira ◽  
Juan Carlos Campos Rubio ◽  
Tulio Hallak Panzera ◽  
João Paulo Davim
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Porous Structure ◽  
Epoxy Polymer ◽  
Complex Geometry ◽  
Microstructural Analysis ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Small Series ◽  
Dimensional Printing

Rapid prototyping for material deposition or additive manufacturing has been widely used for short time production of parts with complex geometry in small series. The three-dimensional printing process needs post-processing to improve the strength, stiffness and/or surface finish of the parts. Printed parts in pristine condition are generally very brittle with a porous structure, so infiltrates have been introduced to improve their mechanical and physical characteristics. This work investigates the effect of two infiltrates, epoxy polymer and cyanoacrylate, under a vacuum pressure system on the mechanical properties of powder-based composites made by three-dimensional printing. Samples printed under pristine and infiltrated conditions were tested under tensile, flexural, compressive and impact loadings. The infiltrated samples achieved superior mechanical properties, especially when the epoxy polymer was applied via a vacuum system. The microstructural analysis showed that the infiltrates were not able to penetrate the entire sample, revealing a porous structure in the centre, mainly when the cyanoacrylate was used. The epoxy polymer infiltrate was able to substantially increase the mechanical performance of three-dimensional samples, being a promising material when higher structural requirements are required.

The three-dimensional fine structure of the human heart: a scanning electron microscopic atlas for research and education

Biologia ◽  
2017 ◽  
Vol 72 (12) ◽  
Author(s):  
Paulína Gálfiová ◽  
Štefan Polák ◽  
Renáta Mikušová ◽  
Andrea Gažová ◽  
Daniel Kosnáč ◽  
...  
Keyword(s):  
Fine Structure ◽  
Human Heart ◽  
Three Dimensional ◽  
Phosphate Buffer Solution ◽  
Heart Tissue ◽  
The Body ◽  
Buffer Solution ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Research And Education

AbstractKnowledge about the three-dimensional fine structure of human heart, as a crucial vital organ of the body, is not only fascinating from the scientific or educational points of view, but has a very important clinical impact. Therefore, we decided to create a three-dimensional atlas of fine structure of the human heart. Tissue samples from ten human hearts were rinsed in phosphate-buffer solution, fixed by glutaraldehyde buffered solution, and post-fixed in osmium tetroxide solution. A gentle dehydration with ethanol in different concentration and drying at the critical point of CO

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

Scanning electron microscopy of freeze-fractured prescapular lymph node of caprine

1984 ◽  
Vol 42 ◽  
pp. 244-245
Author(s):  
O. Faroon ◽  
F. Al-Bagdadi ◽  
T. G. Snider ◽  
C. Titkemeyer
Keyword(s):  
Lymph Node ◽  
Lymph Nodes ◽  
Lymphatic System ◽  
Three Dimensional ◽  
Meat Products ◽  
The Body ◽  
Morphological Data ◽  
The World ◽  
Cellular Constituent ◽  
Scanning Electron

The lymphatic system is very important in the immunological activities of the body. Clinicians confirm the diagnosis of infectious diseases by palpating the involved cutaneous lymph node for changes in size, heat, and consistency. Clinical pathologists diagnose systemic diseases through biopsies of superficial lymph nodes. In many parts of the world the goat is considered as an important source of milk and meat products.The lymphatic system has been studied extensively. These studies lack precise information on the natural morphology of the lymph nodes and their vascular and cellular constituent. This is due to using improper technique for such studies. A few studies used the SEM, conducted by cutting the lymph node with a blade. The morphological data collected by this method are artificial and do not reflect the normal three dimensional surface of the examined area of the lymph node. SEM has been used to study the lymph vessels and lymph nodes of different animals. No information on the cutaneous lymph nodes of the goat has ever been collected using the scanning electron microscope.

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

EMCAT: An automatic image-processing system for electron-microscopic tomography

1994 ◽  
Vol 52 ◽  
pp. 418-419
Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Image Processing ◽  
Structural Information ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Processing System ◽  
Electron Microscopic ◽  
Data Set ◽  
Ordered Structures ◽  
Automatic Image Processing ◽  
Em Tomography

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.

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