scholarly journals DENSITY AND WATER ABSORPTION PROPERTIES OF PMMA REINFORCED BY PEANUT AND WALNUT SHELLS POWDERS USED IN DENTAL APPLICATIONS

2021 ◽  
Vol 21 (1) ◽  
pp. 46-53
Author(s):  
Zainab Moaead Abdul Monem ◽  
Qahtan Adnan Hamad ◽  
Jawad Kadhim Oleiwi
Keyword(s):  
Water Absorption ◽  
Average Particle Size ◽  
Base Material ◽  
Average Particle ◽  
Absorption Properties ◽  
Walnut Shells ◽  
Peanut Shells ◽  
The Matrix ◽  
Dental Applications ◽  
Pmma Resin

Poly Methyl Methacrylate resin distinguished by its low impact and fatigue strength, there are many researches that will deal with these situations. In the current study the matrix was heat cured material powder of PMMA was reinforced with peanut and walnut Shells to PMMA base material, which commonly utilize in the applications of denture. these natural powders were added in various weights fraction (4%, 8%, and 12%), and with similar average particle size (53μm) and studied Density and water absorption properties. In this study the method used to prepare the specimens is Hand Lay-Up method. The results showed that the values of density are increased when the weight fractions of both reinforcing natural particles increased and the maximum value was obtained with adding peanut shells powder at (12 wt.%.) (1.206 gm/????????3) for the composite specimens, while the values of water absorption Tests was decreased by increasing the weight fractions of both reinforcing powders peanut and walnut Shells in PMMA resin and The lowest values was obtained by adding peanut shells powder at (12 wt.% P) (0.003 % ).

Toughening of Polypropylene-Ethylene Copolymer with Nanosized CaCO3 and Styrene-Butadiene-Styrene

2007 ◽  
Vol 121-123 ◽  
pp. 1451-1454
Author(s):  
Jian Feng Chen ◽  
Guo Quan Wang ◽  
Xiao Fei Zeng ◽  
Hong Ying Zhao
Keyword(s):  
Average Particle Size ◽  
Average Particle ◽  
Single Screw Extruder ◽  
Roll Mill ◽  
The Matrix ◽  
Ethylene Copolymer ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
The Impact ◽  
Butadiene Styrene

Nanocomposites of nanosized-CaCO3/polypropylene-ethylene copolymer (PPE) and nanosized CaCO3/ PPE/ styrene-butadiene-styrene (SBS) were prepared by using two-roll mill and single screw extruder. The average particle size of nanosized CaCO3 was determined to be about 30 nm. By adding nanosized CaCO3 into PPE matrix, the toughness of the matrix improves significantly. At nanosized CaCO3 content of 12 phr (parts per hundred PPE resin by weight), the impact strength of CaCO3/PPE at room temperature reaches 61.6 KJ/m2, which is 3.02 times that of unfilled PPE matrix. In addition, the synergistic toughening effect of nanosized CaCO3 and SBS particles on PPE matrix was investigated.

Effect of peanut and walnut shells powders on tensile properties and morphological test by using heat cured PMMA as a matrix for prosthetic Denture

2021 ◽  
Vol 39 (2A) ◽  
pp. 196-205
Author(s):  
Zainab M. Abdul Monem ◽  
Jawad K. Oleiwi ◽  
Qahtan A. Hamad
Keyword(s):  
Fracture Surface ◽  
Surface Morphology ◽  
Matrix Material ◽  
Weight Fraction ◽  
Fracture Surface Morphology ◽  
Ductile Materials ◽  
Walnut Shells ◽  
Peanut Shells ◽  
The Matrix ◽  
Material Powder

In the current Research , the heat cured   matrix material powder of PMMA was reinforced with peanut and walnut shells (natural powders) which are chemically treated with 5% (w/v) (NaOH) to improve the matrix bonding (PMMA) before being used as a reinforcing powder and adding to exactly similar averages particle sizes ≤ (53µm), with different weight fractions of (4, 8, and 12 wt.%). The ASTM D638 is used for composite specimens of the tensile test. The results indicated that the Elastic modulus values reached its maximum value at (8 wt.%.) when reinforced with peanut shells particles (1.053Gpa) , while ,the values of tensile strength, elongation percentage at break, decrease as the weight fraction of peanut and walnut shells powder increase and the lowest values is obtained by reinforcing with peanut shells particles to reach their minimum values at (12 wt.%.) where the lowest values of them are (29 MPa, 2.758% ) respectively. The fracture surface morphology of pure PMMA seemed to be homogenous morphology in (SEM) test, whereas the fracture surface morphology of PMMA composite reinforced by (peanut and walnut shells) powders and shows a roughness fracture surface morphology this refer to semi ductile to ductile materials.

DEVELOPMENT OF A NON-CONTINUOUS MICRO-FLOW OPTO-WETTING DROPLET MANIPULATION TECHNOLOGY

2005 ◽  
Vol 17 (06) ◽  
pp. 293-299 ◽  
Author(s):  
MING-YIH LEE ◽  
HUNG-CHIA LIN ◽  
HUNG-WEI CHIANG ◽  
WEI-XUN LEE ◽  
XIAN-DONG HUANG
Keyword(s):  
Surface Tension ◽  
Uv Light ◽  
Liquid Droplet ◽  
Average Particle Size ◽  
Base Material ◽  
Material Surface ◽  
Average Particle ◽  
Hydrophilic Property ◽  
Manipulation System ◽  
Droplet Manipulation

The aim of this study is to develop a non-continuous droplet manipulation technology in contrast to conventional continuous flow micro-fluidic systems. The droplets were manipulated based on the proposed opto-wetting effect. In addition, an experimental ultraviolet (UV) light actuated droplet manipulation system was developed for verifying the opto-wetting droplet manipulation. The proposed opto-wetting effect was achieved by utilizing ultraviolet to activate oxidation-reduction mechanism of nano-TiO2 photo catalyst coated base material. The water-affinity of the base material will changed due to the decreased free-energy of the material surface. Therefore, the contact angle between the liquid droplet and base material will also be changed which facilitates droplet manipulability. The main components of the proposed ultraviolet (UV) light actuated droplet manipulation system include ultraviolet masking device, moving platform and main frame structure. System software and user interface were designed by using Microsoft Visual Basic 6.0 toolkit. Upon completion of the proposed system, experiments were carried out to verify system functionalities. Follow by the controlled variable optimization using Taguchi method and liquid droplet manipulation experiments. The experiment results indicate that by exposure to 6.8mW UV light, the surface tension and hydrophilic property of nano-TiO2 (anatase type, 3.5% concentration, PH 1.5, and with average particle size of 69 nm) coated base material will changed. The change of surface tension and hydrophilic property were critical for droplet manipulation. The moving speed of the liquid droplet was measured as 3.33mm/sec. The results suggest that the opto-wetting system may be effective to overcome the shortcoming of traditional opto-electrowetting technique. The proposed opto-wetting droplet manipulation system could potentially applied for manipulating biomedical or pathological test specimens in the future.

scholarly journals From Ni–P Metastable Alloy Nanoparticles to Bulk Submicrometer Grain-Sized MMCs with Tunable Mechanical and Magnetic Properties

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 112
Author(s):  
Mohamed Ali Bousnina ◽  
Frédéric Schoenstein ◽  
Silvana Mercone ◽  
Noureddine Jouini
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Magnetic Properties ◽  
Average Particle Size ◽  
Polyol Process ◽  
Magnetic Composite ◽  
Average Particle ◽  
Conventional Heat Treatment ◽  
The Matrix ◽  
Metastable Alloy

In this study, submicrometer grain-sized metal matrix composites (MMCs) based on nickel were elaborated via a bottom-up strategy combining the polyol process and a non-conventional heat treatment route. First, four sets of nano-sized Ni–P metastable alloy nanopowders with an average particle size centered at 50, 100, 130, and 220 nm were prepared by the polyol process modified by the addition of hypophosphite (strong reducing agent) and heterogeneous nucleation using silver nitrate and platinum salt (nucleating agents). The heat treatment step was realized by reactive spark plasma sintering (R-SPS) at identical heat treatment conditions (600 °C, 53 MPa, and 10 min as holding time). R-SPS transformed the Ni–P metastable alloys into bulk submicrometer grain-sized MMCs with Ni as the matrix and Ni3P as the reinforcement. Mechanical and magnetic properties of the four MMC samples were found to be closely related to the grain size of the Ni matrix, which varied from 247 to 638 nm. Yield stress, maximum stress, and coercive field increased when the grain size decreased, while plastic strain and magnetization saturation decreased. The reinforcement Ni3P phase enhanced the mechanical characteristics of the composite. Crossover behavior was observed at around 350 nm Ni grain size, where a ductile and soft magnetic composite was tuned into a hard mechanical and semi-hard magnetic one.

Synthesis and Characterization of Peptidomimetic Self-Assembled Biodegradable Nanoparticles

2009 ◽  
Vol 1238 ◽  
Author(s):  
Àngel E. Mercado-Pagán ◽  
Esmaiel Jabbari
Keyword(s):  
Particle Size ◽  
Degradation Kinetics ◽  
Average Particle Size ◽  
Active Agent ◽  
Polymer Chains ◽  
Peptide Sequence ◽  
Aqueous Environment ◽  
Average Particle ◽  
Self Assembling ◽  
The Matrix

AbstractNanoparticles (NPs) are being used extensively for tumor drug delivery. These devices offer the advantage of their size, protection of the encapsulated species, and biodegradability to prevent accumulation in the interstitium. Our laboratory has synthesized polylactide fumarate (PLAF, PLGF) macromers capable of self-assembling into biodegradable and biocompatible NPs with average particle size of 280 nm. To assess the possibility of further decreasing the particle size and distribution of PLGF NPs, the polymers were conjugated with the peptide sequence Cys-Val-Val-Val-Val-Val-Val-Lys-Lys (CV6K2), which is known to self-assemble in aqueous solution into vesicles of about 50-60 nm in size. The results indicate that the PLGF-CV6K2 conjugates are capable of self-assembling into NPs of 100 nm in diameter. The NPs are proposed as having a bilayer structure, with peptide chains facing the aqueous environment and the polymer chains compacted in an internal hydrophobic layer. Degradation kinetics and release profiles show that the NPs could effectively retain and release Paclitaxel up to 30 days until completely degraded. The NPs act as reservoirs for sustained release of the active agent by diffusion and degradation of the matrix when taken up by tumor cells.

scholarly journals Solidification characteristics of atomized AlCu4Mg1-SiC composite powders

2012 ◽  
Vol 48 (1) ◽  
pp. 73-79 ◽  
Author(s):  
R. Yamanoglu ◽  
M. Zeren ◽  
Randall German
Keyword(s):  
Particle Size ◽  
Matrix Material ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Average Particle ◽  
Composite Powders ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
The Matrix ◽  
Rapidly Solidified

In this study, rapidly solidified metal matrix composite powders have been produced by PREP (Plasma rotating electrode process) atomization. AlCu4Mg1 alloy is used as the matrix material while SiC particles, with about 650 nm average particle size, are used as the reinforcement phase. The microstructural and solidification characteristics of composite particles are studied using optical and scanning electron microscope (SEM). The relationship between secondary dendrite arm spacing (SDAS) and particle diameter was examined, and these composite powders were found to have dendritic and equiaxed solidification with a fine eutectic phase. SDAS measurements using various sized particles show that secondary dendrite arm spacing slightly decreases with the decrease in particle size.

The tribological performance of brucite lubricant at high temperature

2017 ◽  
Vol 69 (5) ◽  
pp. 621-626
Author(s):  
Xueping Hu ◽  
Pengfei Tang ◽  
Yanfei Wang ◽  
Jing Liu
Keyword(s):  
High Temperature ◽  
Tap Water ◽  
Average Particle Size ◽  
Base Material ◽  
Tribological Performance ◽  
Working Fluid ◽  
Average Particle ◽  
Content Type ◽  
Water Based ◽  
Treatment Agent

Purpose Water-based graphite lubricants have good lubricity in the process of metal forming, especially for hot-rolling seamless pipe. Although the use of water as a working fluid system instead of conventional mineral oil has many advantages for the fuel consumption, post cleaning and a new type of lubricant, the graphite contaminated the machine and workers for its physical properties. From the global environmental protection viewpoint, it is urgent to develop a kind of benign material. Design/methodology/approach Magnesium hydroxide which has the average particle size of 10 μm was chosen as a base material without further modification and pretreatments. On the HT-1000 high-temperature tribometer, the influence of temperature and lubricant materials on the friction coefficient was studied. The tribological performance at 900°C provided evidence under high temperature for exploring a new lubricant material. Findings Tap water-based brucite lubricant will open a new chapter in the industrial lubrication, effectively avoiding many unfavorable factors caused by graphite lubrication, such as conductivity, pollution and energy loss. Meanwhile, it expanded the application of brucite as flame-retardant agent, catalyst, water treatment agent and so on. Originality/value It is a new and environmental lubricant to tap water-based brucite lubricant. And specially, the preparation process of lubricant is simple and economical.

Preparation and Properties of Magnesium-Aluminum Matrix Composites Reinforced with Silicon Carbon Particles

2012 ◽  
Vol 583 ◽  
pp. 3-8 ◽  
Author(s):  
Tan Wei Zhou ◽  
Xiang Rong Liu ◽  
Run Lan Zhang ◽  
Zhuang Zhuang Su
Keyword(s):  
Average Particle Size ◽  
Aluminum Matrix ◽  
Optical Microscope ◽  
Aluminum Matrix Composites ◽  
Al Alloy ◽  
Average Particle ◽  
Carbon Particles ◽  
Sic Particles ◽  
Silicon Carbon ◽  
The Matrix

Mg-5wt.%Al alloy based composites reinforced with 0wt.%, 1wt.%, 2wt.% silicon carbon (SiC) particles (average particle size about 3.5µm) were prepared under flux protection conditions. The microstructures, textures, components and hardness of the above composites were investigated through optical microscope, scanning electron microscope, X-ray diffraction and sclerometer. The results indicate that SiC particles are distributed along grain boundaries, limiting grain growth and conducing to the refinement of the matrix. The hardness of composites increases with the increase of SiC particles addition amount. The presences of Mg2Si and the binary carbide Al4C3 were observed in the composites. The Al4C3 phase has a crystal structure closer to that of Mg than to that of SiC, which can be act as a potential nucleant for Mg-5wt.%Al alloy.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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