334,924 research outputs found
KAPASITAS LENTUR, TOUGHNESS, DAN STIFFNESS BALOK BETON BERSERAT POLYETHYLENE
Abstract
The common problems of concrete are brittle failure and low of tension. Fiber reinforced plastic concrete is one
of the alternatives to solve the problems. This research aim is to demonstrate a contribution of Polyethylene to
revise the weakness of its properties. An experiment has been conducted to observe compressive strength,
toughness, modulus of rupture and stiffness of fiber-polyethylene-reinforced concrete. The results show that by
adding Polyethylene as a fiber in concrete material, compressive strength increases to 120.36%, moment
capacity of beam increases to 115.79% and toughness increases to 318.6% compared with normal concrete.
Hence, it can be stated that the addition of Polyethylene fiber has a significant contribution to increase the
concrete performances.
Keywords:
concrete, fiber, polyethylene, stiffness, toughness
Superior thermal conductivity and extremely high mechanical strength in polyethylene chains from {\it ab initio} calculation
The upper limit of the thermal conductivity and the mechanical strength are
predicted for the polyethylene chain, by performing the {\it ab initio}
calculation and applying the quantum mechanical non-equilibrium Green's
function approach. Specially, there are two main findings from our calculation:
(1). the thermal conductivity can reach a high value of 310 W/K/m in a 100 nm
polyethylene chain at room temperature; (2). the Young's modulus in the
polyethylene chain is as high as 374.5 GPa, and the polyethylene chain can
sustain (ultimate) strain before undergoing structural phase
transition into gaseous ethylene.Comment: published in J. Appl. Phys. (2012
The Optical Behavior of Polyethylene Spherulites
Polyethylene was crytallized from the molten film under temperature gradient. As a result, the optically positive spherulites were observed, though only the negative spherulites had been observed previOusly in polyethylene. When the radial structure units twisted regulary in a spherulite are formed parallel to the surface of the film, the spberulite is usually optically negative in polyethylene. In this study, the temperature gradient normal to the surface of the film gives so significant tilt of the radial structure units formed to the surface of the film that the radial refractive index becomes larger than
the tangential one under the transmitted polarized light and the spherulites have optically positive behavior. The optical behaviors of the polyethylene spherulites and the crystallizing condition were studied and discussed
Method for casting polyethylene pipe
Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene
FDM preparation of bio-compatible UHMWPE polymer for artificial implant
Due to its properties of high wear, creep resistance, high stiffness and strength, Ultra-High Molecular Weight Polyethylene (UHMWPE) was developed to eliminate most metallic wear in artificial implant, which conventionally found in stainless steel, Cobalt Chromium (Co-Cr) and Titanium (Ti) alloys. UHMWPE has an ultra-high viscosity that renders continuous melt-state processes including one of the additive manufacturing processes, Fused Deposition Modeling (FDM) ineffective for making UHMWPE implant. Attempt to overcome this problem and adapting this material to FDM is by blending UHMWPE with other polyethylene including High Density Polyethylene (HDPE) and Polyethylene-Glycol (PEG) which provide adequate mechanical properties for biomedical application along with the improvement in extrudability. It was demonstrated that the inclusion of 60% HDPE fraction has improved the flowability of UHMWPE in MFI test and showing adequate thermal stability in TGA
Hybrid materials based on polyethylene and MCM-41 microparticles functionalized with silanes: catalytic aspects of in situ polymerization, crystalline features and mechanical properties
New nanocomposites based on polyethylene have been prepared by in situ polymerization of ethylene in
presence of mesoporous MCM-41. The polymerization reactions were performed using a zirconocene
catalyst either under homogenous conditions or supported onto mesoporous MCM-41 particles, which
are synthesized and decorated post-synthesis with two silanes before polymerization in order to promote
an enhanced interfacial adhesion. The existence of polyethylene chains able to crystallize within
the mesoporous channels in the resulting nanocomposites is figured out from the small endothermic
process, located at around 80 C, on heating calorimetric experiments, in addition to the main melting
endotherm. These results indicate that polyethylene macrochains can grow up during polymerization
either outside or inside the MCM-41 channels, these keeping their regular hexagonal arrangements.
Mechanical response is observed to be dependent on the content in mesoporous MCM-41 and on the
crystalline features of polyethylene. Accordingly, stiffness increases and deformability decreases in the
nanocomposites as much as MCM-41 content is enlarged and polyethylene amount within channels is
raised. Ultimate mechanical performance improves with MCM-41 incorporation without varying the
final processing temperature
Penelitian Pengaruh Penggunaan Riklim Politilen Terhadap Sifat Ketahanan Pukul Dan Kekerasan
The aim of this research is to know further about the influence ot polyethylene reclaim to the characteristic of impact resistance and high density polyethylene (HDPE) compound.The research is done by making HDPE compound with the addition of polyethylene reclaim with various procentage of quantity.In fact the addition on of HDPE reclaim into pure HDPE doesn\u27t influence the hardness of the compound produced, but it influence the impact resistance to signification phase P 0,05 by linear aquation Y = 10,26 + 0,0887.The compound hardness is approximately 63,2 – 64,0 shore D, and impact resistance is approximately 10,83 – 18,91 kgcm/cm in various variation
Growing Sweetcorn in Alaska's Cool Environments
Sweet corn can be grown in
Alaska's cool environments by employing
clear polyethylene mulch to
raise soil temperatures.
Rows should be run north and
south, spaced about 5 feet apart for
4-foot wide mulch.
Weeds can be controlled under
clear polyethylene mulch by spraying
with atrazine after seeding and
before mulching
Low temperature thermal expansivities of polyethylene, polypropylene and their mixtures
Low temperature measurements of length- temperature curves of polyethylene, polypropylene, mixtures of polyethylene and polypropylene, and copolymer
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