scholarly journals Self-Limiting Electrospray Deposition for the Surface Modification of Additively Manufactured Parts

2019 ◽  
Author(s):  
Dylan A. Kovacevich ◽  
Lin Lei ◽  
Daehoon Han ◽  
Christianna Kutznetsova ◽  
Howon Lee ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Spray Coating ◽  
The Body ◽  
Line Of Sight ◽  
Electrospray Deposition ◽  
Three Dimensional Objects ◽  
Humidity Response ◽  
Surface Functionality ◽  
Over Time ◽  
Flowing Solution

Electrospray deposition (ESD) is a spray coating process that utilizes a high voltage to atomize a flowing solution into charged microdroplets. These self-repulsive droplets evaporate as they travel to a target substrate, depositing the solution solids. Our previous research investigated the conditions necessary to minimize charge dissipation and deposit a thickness-limited film that grows in area over time through self-limiting electrospray deposition (SLED). Such sprays possess the ability to conformally coat complex three-dimensional objects without changing the location of the spray needle or orientation of the object. This makes them ideally suited for the post-processing of materials fabricated through additive manufacturing (AM), opening a paradigm of independent bulk and surface functionality. Having demonstrated three-dimensional coating with film thickness in the range of 1-50 µm on a variety of conductive objects, in this study we employed model substrates to quantitatively study the technique’s limits with regard to geometry and scale. Specifically, we examined the effectiveness of thickness-limited ESD for coating recessed features with gaps ranging from 50 µm to 1 cm, as well as the ability to coat surfaces hidden from the line-of-sight of the spray needle. This was then extended to the coating of hydrogel structures printed by AM, demonstrating that coating could be conducted even into the body of the structures as a means to create hydrophobic surfaces without affecting the absorption-driven humidity response.

scholarly journals Self-Limiting Electrospray Deposition for the Surface Modification of Additively Manufactured Parts

2019 ◽  
Author(s):  
Dylan A. Kovacevich ◽  
Lin Lei ◽  
Daehoon Han ◽  
Christianna Kutznetsova ◽  
Howon Lee ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Spray Coating ◽  
The Body ◽  
Line Of Sight ◽  
Electrospray Deposition ◽  
Three Dimensional Objects ◽  
Humidity Response ◽  
Surface Functionality ◽  
Over Time ◽  
Flowing Solution

Electrospray deposition (ESD) is a spray coating process that utilizes a high voltage to atomize a flowing solution into charged microdroplets. These self-repulsive droplets evaporate as they travel to a target substrate, depositing the solution solids. Our previous research investigated the conditions necessary to minimize charge dissipation and deposit a thickness-limited film that grows in area over time through self-limiting electrospray deposition (SLED). Such sprays possess the ability to conformally coat complex three-dimensional objects without changing the location of the spray needle or orientation of the object. This makes them ideally suited for the post-processing of materials fabricated through additive manufacturing (AM), opening a paradigm of independent bulk and surface functionality. Having demonstrated three-dimensional coating with film thickness in the range of 1-50 µm on a variety of conductive objects, in this study we employed model substrates to quantitatively study the technique’s limits with regard to geometry and scale. Specifically, we examined the effectiveness of thickness-limited ESD for coating recessed features with gaps ranging from 50 µm to 1 cm, as well as the ability to coat surfaces hidden from the line-of-sight of the spray needle. This was then extended to the coating of hydrogel structures printed by AM, demonstrating that coating could be conducted even into the body of the structures as a means to create hydrophobic surfaces without affecting the absorption-driven humidity response.

scholarly journals A pilot study on the use of 3D printers in veterinary medicine

2021 ◽  
Vol 14 (3) ◽  
pp. 159-164
Author(s):  
Leonardo Leonardi ◽  
◽  
Roberto Marsili ◽  
Enrico Bellezza ◽  
Giovanni Angeli ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Bone Tissue ◽  
Three Dimensional ◽  
The Body ◽  
Porous Scaffolds ◽  
Layer By Layer ◽  
Three Dimensional Objects ◽  
Cellular Attachment

Additive manufacturing (AM) is the process of joining materials to create layer-by-layer three-dimensional objects using a 3D printer from a digital model. The great advantage of Additive Manufacturing is to allow a freer design than traditional processes. The development of additive manufacturing processes has permitted to optimize the production of the customized product through the modeling of the geometry and the knowledge of the morphometric parameters of the body structures. 3D printing has revolutionized the field of Regenerative Medicine because, starting from computerized tomography (CT) images and using traditional materials such as plastic and metals, it can provide customized prostheses for each patient, which adapt perfectly to the needs of the subject and act as structures support. 3D printing allows you to print three-dimensional porous scaffolds with a precise shape and chemical composition suitable for medical and veterinary use. Some of these scaffolds are biodegradable and appear to be ideal for bone tissue engineering. In fact, they are able to simulate extracellular matrix properties that allow mechanical support, favoring mechanical interactions and providing a model for cellular attachment and in vivo stimulation of bone tissue formation.

Moving around Objects and Recognizing Them

1998 ◽  
Vol 86 (1) ◽  
pp. 267-276 ◽  
Author(s):  
F. Giusberti ◽  
T. Iachini ◽  
F. Pavani
Keyword(s):  
Mental Rotation ◽  
Spatial Information ◽  
Angular Displacement ◽  
Three Dimensional ◽  
Linear Increase ◽  
The Body ◽  
Experimental Task ◽  
Three Dimensional Objects ◽  
Spatial Properties ◽  
Rotated Objects

This research concerned the use of mental rotation in recognizing rotated objects. Instead of the classic Shepard's paradigm in which subjects were still while observing rotated objects, here subjects had to move (or imagine moving) around stationary three-dimensional objects put in the middle of the trajectory. Thus, depending on the viewing positions, such objects were seen under six different perspectives (from 30° to 180°). The latter task has been thought to be closer to everyday life in which we obtain information regarding objects from their spatial properties. The results do not follow the classic rules of mental rotation of an object predicting a linear increase of the time needed to recognize distorted objects as a function of their angular displacement. They also differ from data in the Literature about spatial imagery showing that access to spatial information is facilitated more when people actually move through a path than when they imagine moving. A probable explanation of this difference from the literature is discussed in relation to the particular involvement of the body in the experimental task.

Visual Rhetoric

2018 ◽  
Author(s):  
Zazil Reyes García
Keyword(s):  
Visual Rhetoric ◽  
Three Dimensional ◽  
The Body ◽  
Visual Images ◽  
Late 20Th Century ◽  
Three Dimensional Objects ◽  
Video Advertising ◽  
The World ◽  
Visual Artifacts ◽  
Written Word

The growing field of visual rhetoric explores the communicative and persuasive power of the visual artifacts that surround us. This relatively new branch of rhetoric emerged in the late 20th century, disrupting a discipline that was traditionally concerned with the spoken and written word. The artifacts studied through the lens of visual rhetoric comprise visual images and objects that are human created and culturally meaningful. They include two-dimensional images, such as political cartoons and video advertising, and three-dimensional objects such as museums and murals. Visual rhetoric can also include the analysis of embodied performance and thus examine the body as argument. Although much of the scholarship focuses on the power of images in shaping people’s understanding of the world, there is also a recognition of the power of looking. Meaning does not reside in the images around us; we participate in its construction. To better understand visual rhetoric, it is important to review its emergence as an area of study, its definitions, and some of the recurring themes in the scholarship.

Plasma and Electrospray Deposition to Improve the Biocompatibility of Stents

2007 ◽  
Vol 539-543 ◽  
pp. 529-534 ◽  
Author(s):  
Michael Tatoulian ◽  
Enrico Gallino ◽  
R. Jafari ◽  
Farzaneh Arefi-Khonsari ◽  
L. Tatoulian ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Three Dimensional ◽  
Film Coating ◽  
Polymer Coatings ◽  
The Body ◽  
Metallic Ions ◽  
Ion Release ◽  
Three Dimensional Objects ◽  
Intravascular Stents ◽  
The Stability

Metallic Intravascular stents are medical devices used to scaffold a biological lumen, mostly diseased arteries, after balloon angioplasty. They are commonly made of 316L stainless steel or Nitinol, two alloys containing Nickel, an element classified as potentially toxic and carcinogenic. Although they are largely implanted, the long-term safety of such metallic elements is still controversial, since the corrosion processes may lead to the release of several metallic ions. In order to avoid the metallic ion release in the body and to improve the biocompatibility of metallic stents with their biological environments, polymer coatings have been deposited by two different technologies, i.e. plasma surface modifications and Electrospraying. The role of the polymer coating is then to encapsulate the stainless steel device, and to favour the chemical grafting of Phosphorylcholine, a molecule known for its hemocompatible properties.1 In this talk, the state of the art on low pressure and atmospheric pressure plasmas for deposition of organic coatings will be given and we will present the advantages and drawbacks of each process. Then, we will present an original technology that combine a Dielectric Barrier Discharge and an electrospraying system to deposit well-defined Polyacrylic acid and Polyallylamine films. The advantage of such system is the possibility to limit the extent of the monomer fragmentation and to give rise to rapid deposition of a highly functionalised plasma polymer layer, and also the possibility to cover three dimensional objects, such as stents. Thus, the theory of EHDA technology will be explained: special attention has been paid to define the Electrospray parameters (Voltage, flow of precursor, nozzle-substrate distance…) which control the size distribution of the charged droplets and as a consequence, the structure of the film coating. The film coatings have been analysed with XPS and by ATR. Moreover, special attention will be paid on the stability of the coating which is related to both spraying conditions as well as to the preliminary plasma treatment. The potentiality and the features of the EHDA process will be then presented.

scholarly journals Water entry of a body which moves in more than six degrees of freedom

2015 ◽  
Vol 471 (2177) ◽  
pp. 20150058 ◽  
Author(s):  
Y.-M. Scolan ◽  
A. A. Korobkin
Keyword(s):  
Degrees Of Freedom ◽  
Early Stage ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Oblique Impact ◽  
Water Entry ◽  
The Body ◽  
Body Motion ◽  
Elliptic Paraboloid ◽  
Over Time

The water entry of a three-dimensional smooth body into initially calm water is examined. The body can move freely in its 6 d.f. and may also change its shape over time. During the early stage of penetration, the shape of the body is approximated by a surface of double curvature and the radii of curvature may vary over time. Hydrodynamic loads are calculated by the Wagner theory. It is shown that the water entry problem with arbitrary kinematics of the body motion, can be reduced to the vertical entry problem with a modified vertical displacement of the body and an elliptic region of contact between the liquid and the body surface. Low pressure occurrence is determined; this occurrence can precede the appearance of cavitation effects. Hydrodynamic forces are analysed for a rigid ellipsoid entering the water with 3 d.f. Experimental results with an oblique impact of elliptic paraboloid confirm the theoretical findings. The theoretical developments are detailed in this paper, while an application of the model is described in electronic supplementary materials.

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.

Opponent Center-Surround Contrast: Colour to Grey Conversion

2020 ◽  
Vol 2020 (1) ◽  
pp. 105-108
Author(s):  
Ali Alsam
Keyword(s):  
Evolutionary Algorithms ◽  
Three Dimensional ◽  
The State ◽  
Colour Space ◽  
Vision Science ◽  
State Of Art ◽  
Over Time

Vision is the science that informs us about the biological and evolutionary algorithms that our eyes, opticnerves and brains have chosen over time to see. This article is an attempt to solve the problem of colour to grey conversion, by borrowing ideas from vision science. We introduce an algorithm that measures contrast along the opponent colour directions and use the results to combine a three dimensional colour space into a grey. The results indicate that the proposed algorithm competes with the state of art algorithms.

To the theory analysis of tightness of tank of pressure testing

2019 ◽  
Vol 5 (4) ◽  
pp. 129-142
Author(s):  
Vladislav Sh. Shagapov ◽  
Ismagilyan G. Khusainov ◽  
Emiliya V. Galiakbarova ◽  
Zulfya R. Khakimova
Keyword(s):  
Relaxation Time ◽  
Three Dimensional ◽  
Petroleum Products ◽  
Technical Condition ◽  
Excess Pressure ◽  
Soil Parameters ◽  
Theory Analysis ◽  
Pressure Testing ◽  
Tank Pressure ◽  
Over Time

This article studies the process of relaxation of the pressure in a tank with the damaged area of the wall after pressure-testing. The authors use different methods for the diagnosis of the technical condition of objects of petroleum products storage. Pressure testing is one of nondestructive methods. The rate of pressure decrease is characteristic of the system tightness. This article studies the cases of ground and underground location of the tank. Pressure testing involves excess pressure inside of a tank and observing its decrease. Over time, one can assess the integrity of the system. This has required creating mathematical models to account the filtration of the liquid depending on the location of the tank. The results include the analytical solution of the task and the formulas for describing the dependence of the relaxation time of pressure in the tank from the liquid and soil parameters, geometry of the tank, and the damaged portion of the wall. The two- and three-dimensional cases of liquids filtration for the case of underground location of the tank were considered. The results of some numerical calculations of the dependence of reduction time and the time of half-life pressure from the area of the damaged portion of the wall were shown. The obtained solutions allow assessing the extent of the damaged area by the pressure testing with known values of tank, liquid, and soil.

CALCULATION OF THE DEPENDENCE OF THE DISTANCE TO THE LOCATED OBJECT FROM THE CORNER POSITION OF THE VEHICLE LINE

2018 ◽  
pp. 14-18
Author(s):  
V. V. Artyushenko ◽  
A. V. Nikulin
Keyword(s):  
Real Time ◽  
Statistical Physics ◽  
Angular Position ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Two Dimensional ◽  
Radar Station ◽  
Flight Mode ◽  
Vector Algebra ◽  
Analytical Expressions

To simulate echoes from the earth’s surface in the low flight mode, it is necessary to reproduce reliably the delayed reflected sounding signal of the radar in real time. For this, it is necessary to be able to calculate accurately and quickly the dependence of the distance to the object being measured from the angular position of the line of sight of the radar station. Obviously, the simplest expressions for calculating the range can be obtained for a segment or a plane. In the text of the article, analytical expressions for the calculation of range for two-dimensional and three-dimensional cases are obtained. Methods of statistical physics, vector algebra, and the theory of the radar of extended objects were used. Since the calculation of the dependence of the range of the object to the target from the angular position of the line of sight is carried out on the analytical expressions found in the paper, the result obtained is accurate, and due to the relative simplicity of the expressions obtained, the calculation does not require much time.

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