scholarly journals Processing and Structure of Carbon Nanofiber Paper

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Zhongfu Zhao ◽  
Jihua Gou ◽  
Aurangzeb Khan
Keyword(s):  
Carbon Nanofibers ◽  
Acid Treatment ◽  
Carbon Nanofiber ◽  
Essential Element ◽  
Process Conditions ◽  
Processing Conditions ◽  
Different Types ◽  
Design And Manufacture ◽  
Dispersion Quality

A unique concept of making nanocomposites from carbon nanofiber paper was explored in this study. The essential element of this method was to design and manufacture carbon nanofiber paper with well-controlled and optimized network structure of carbon nanofibers. In this study, carbon nanofiber paper was prepared under various processing conditions, including different types of carbon nanofibers, solvents, dispersants, and acid treatment. The morphologies of carbon nanofibers within the nanofiber paper were characterized with scanning electron microscopy (SEM). In addition, the bulk densities of carbon nanofiber papers were measured. It was found that the densities and network structures of carbon nanofiber paper correlated to the dispersion quality of carbon nanofibers within the paper, which was significantly affected by papermaking process conditions.

Use of Graphite Nanofibers as a Novel Catalyst Support Medium for Hydrogenation Reactions

1996 ◽  
Vol 454 ◽  
Author(s):  
C. Park ◽  
N. M. Rodriguez ◽  
R. T. K. Baker
Keyword(s):  
Carbon Nanofibers ◽  
Carbon Nanofiber ◽  
Catalyst Support ◽  
Catalytic Behavior ◽  
Graphite Nanofibers ◽  
Nickel Particles ◽  
Support Medium ◽  
Different Types ◽  
Hydrogenation Reactions ◽  
Novel Catalyst

ABSTRACTIn this investigation we elected to use the hydrogenation of 1-butene as probe reactions in an attempt to monitor any possible changes in catalytic behavior resulting from supporting 5 wt.% nickel on different types of carbon nanofibers compared to the performance of the same metal loading on more traditional carriers, including γ-Al2O3 and active carbon. In all cases the carbon nanofiber supported nickel particles are found to exhibit superior activity and significant changes in selectivity to that found from the same metal supported on traditional carriers.

Experimental Research on Impact Line of Hyperboloid Shallow Shell

2010 ◽  
Vol 139-141 ◽  
pp. 567-570
Author(s):  
Li Hong Zhao ◽  
Zheng Yi Ren ◽  
Shu Yong Jiang ◽  
Nan Yang
Keyword(s):  
Process Conditions ◽  
Forming Process ◽  
Shape Accuracy ◽  
Test Analysis ◽  
Shallow Shells ◽  
Blank Holding Force ◽  
Auto Body ◽  
Design And Manufacture ◽  
The Impact

Impact line is one of important factors to affect the shape accuracy and surface quality of auto body panel design and manufacture. It is difficult to study because of the complexity shape of auto body panels. The system of test analysis on impact line is established by analyzing the shapes and forming processes of auto-body panels, of which based on hyperboloid shallow shells. The criterion and research technique of impact line are introduced. Extensive experiment results, which show the effects of forming process conditions, such as blank holding force, draw bead arrangement, and lubrication on impact line, are achieved. It can be concluded that the draw bead arrangement significantly influence the impact line, the displacement of impact line is different with difference of blank holding force and the friction coefficient.

scholarly journals Quality over Quantity: How Different Dispersion Qualities of Minute Amounts of Nano-Additives Affect Material Properties in Powder Bed Fusion of Polyamide 12

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5322
Author(s):  
Alexander Sommereyns ◽  
Stan Gann ◽  
Jochen Schmidt ◽  
Abootorab Baqerzadeh Chehreh ◽  
Arne Lüddecke ◽  
...  
Keyword(s):  
Material Properties ◽  
Carbon Nanoparticles ◽  
Material Behavior ◽  
Process Conditions ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Polyamide 12 ◽  
Nano Additives ◽  
Dispersion Quality

The great interest, within the fields of research and industry, in enhancing the range and functionality of polymer powders for laser powder bed fusion (LB-PBF-P) increases the need for material modifications. To exploit the full potential of the additivation method of feedstock powders with nanoparticles, the influence of nanoparticles on the LB-PBF process and the material behavior must be understood. In this study, the impact of the quantity and dispersion quality of carbon nanoparticles deposited on polyamide 12 particles is investigated using tensile and cubic specimens manufactured under the same process conditions. The nano-additives are added through dry coating and colloidal deposition. The specimens are analyzed by tensile testing, differential scanning calorimetry, polarized light and electron microscopy, X-ray diffraction, infrared spectroscopy, and micro-computed tomography. The results show that minute amounts (0.005 vol%) of highly dispersed carbon nanoparticles shift the mechanical properties to higher ductility at the expense of tensile strength. Despite changes in crystallinity due to nano-additives, the crystalline phases of polyamide 12 are retained. Layer bonding and part densities strongly depend on the quantity and dispersion quality of the nanoparticles. Nanoparticle loadings for CO2 laser-operated PBF show only minor changes in material properties, while the potential is greater at lower laser wavelengths.

scholarly journals IMPACTS OF WATER POLLUTION ON HUMAN HEALTH: A CASE STUDY OF DELHI

2020 ◽  
Author(s):  
Zeba Zarin Ansari ◽  
◽  
S.V. Akhmatov ◽  
Keyword(s):  
Water Pollution ◽  
Essential Element ◽  
Research Area ◽  
Polluted Water ◽  
Human Beings ◽  
The Earth ◽  
Different Types ◽  
The Given

Water is an essential element for all the existing living beings. About 70% of the Earth is covered by water. All human beings need fresh drinking water. Without water no life is ever imagined on this blue planet. But life becomes difficult when many lives have to live on polluted water. According to WHO, 80% diseases are waterborne. In Delhi, different types of toxic chemical discharge have different effects on humans causing diseases like bacterial, viral or parasitic. Therefore, it is recommended to focus daily on the water quality of Delhi from destructive events. So, the present paper defines condition of water pollution and their solutions in the given research area.

Cytocompatibility of Carbon Nanofiber Materials for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Carbon Fiber ◽  
Surface Energy ◽  
Carbon Nanofibers ◽  
Carbon Fibers ◽  
Carbon Nanofiber ◽  
Fiber Composite ◽  
Scar Tissue ◽  
Pc 12 Cells ◽  
Low Surface Energy ◽  
Poly Carbonate

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.

Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Material Properties ◽  
Carbon Nanofiber ◽  
Scar Tissue ◽  
Tissue Response ◽  
Positive Interactions ◽  
Weight Percentage ◽  
Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

Network analysis models – the secret for success

2004 ◽  
Vol 4 (5-6) ◽  
pp. 383-388
Author(s):  
D.M. Rogers
Keyword(s):  
Mathematical Model ◽  
Field Data ◽  
Essential Element ◽  
Distribution Networks ◽  
Automatic Calibration ◽  
Supply And Distribution ◽  
The World ◽  
Optimum Approach ◽  
Analysis Models

Water is a fundamental necessity of life. Yet water supply and distribution networks the world over are old and lacking in adequate maintenance. Consequently they often leak as much water as they deliver and provide an unacceptable quality of service to the customer. In certain parts of the world, water is available only for a few hours of the day. The solution is to build a mathematical model to simulate the operation of the real network in all of its key elements and apply it to optimise its operation. To be of value, the results of the model must be compared with field data. This process is known as calibration and is an essential element in the construction of an accurate model. This paper outlines the optimum approach to building and calibrating a mathematical model and how it can be applied to automatic calibration systems.

Enumeration of Cryptosporidium oocysts from surface water concentrates by laser-scanning cytometry

2000 ◽  
Vol 41 (7) ◽  
pp. 197-202 ◽  
Author(s):  
F. Zanelli ◽  
B. Compagnon ◽  
J. C. Joret ◽  
M. R. de Roubin
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Laser Scanning ◽  
Immunomagnetic Separation ◽  
Entire Surface ◽  
Cryptosporidium Oocysts ◽  
Different Types ◽  
Laser Scanning Cytometry ◽  
Direct Microscopic Observation

The utilization of the ChemScan® RDI was tested for different types of water concentrates. Concentrates were prepared by cartridge filtration or flocculation, and analysed either without purification, or after Immunomagnetic separation (IMS) or flotation on percoll-sucrose gradients. Theenumeration of the oocysts was subsequently performed using the ChemScan® RDI Cryptosporidium application. Enumeration by direct microscopic observation of the entire surface of the membrane was carried out as a control, and recoveries were calculated as a ratio between the ChemScan® RDI result and the result obtained with direct microscopic enumeration. The Chemscan enumeration technique proved reliable, with recoveries yielding close to 100% in most cases (average 125%, range from 86 to 467%) for all the concentration/purification techniques tested. The quality of the antibodies was shown to be critical, with antibodies from some suppliers yielding recoveries a low as 10% in some cases. This difficulty could, however, be overcome by the utilization of the antibody provided by Chemunex. These data conclusively prove that laser scanning cytometry, which greatly facilitates the microscopic enumeration of Cryptosporidium oocysts from water samples and decreases the time of observation by four to six times, can be successfully applied to water concentrates prepared from a variety of concentration/purification techniques.

FACTOR OF QUALITY FOR PASSIVE NON-TUNABLE BAND-STOP FILTERS

2019 ◽  
pp. 71-74
Author(s):  
N. I. Unru ◽  
E. I. Ashcherbagin
Keyword(s):  
Quality Criterion ◽  
Physical Structure ◽  
Electrical Characteristics ◽  
Central Frequency ◽  
Analytical Expression ◽  
Notch Band ◽  
Attenuation Level ◽  
Calculation Results ◽  
Design And Manufacture

The notion of a quality criterion for non-tunable band-stop filters is introduced, and on the basis of it a comparison of filters with different designs is performed. The quality criterion takes into account the electrical characteristics of the filter and its dimensions, including the volume, the central frequency of the notch band, the level of total losses in the passbands, the width of the notch band by the level of total losses, the width of the notch band by attenuation level. Thus, it allows you to compare the quality of design and manufacture of passive notch filters of various types. The necessary analytical expression is presented, and for a number of variants of filter execution, the corresponding calculation results are given. The stated materials allow us to estimate and optimize the system of interrelated parameters of filters of an arbitrary physical structure.

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