Abstract: The material behavior of graphene, a single layer of
carbon lattice, is extremely sensitive to its dielectric environment. We
demonstrate improvement in electronic performance of graphene
nanowire interconnects with full encapsulation by lattice-matching,
chemically inert, 2D layered insulator hexagonal boron nitride (h-
BN). A novel layer-based transfer technique is developed to construct
the h-BN/MLG/h-BN heterostructures. The encapsulated graphene
wires are characterized and compared with that on SiO2 or h-BN
substrate without passivating h-BN layer. Significant improvements
in maximum current-carrying density, breakdown threshold, and
power density in encapsulated graphene wires are observed. These
critical improvements are achieved without compromising the carrier
transport characteristics in graphene. Furthermore, graphene wires
exhibit electrical behavior less insensitive to ambient conditions, as
compared with the non-passivated ones. Overall, h-BN/graphene/h-
BN heterostructure presents a robust material platform towards the
implementation of high-speed carbon-based interconnects.
Abstract: Nanocomposites of isotactic polypropylene (iPP) and
date wood fiber were prepared after modification of the host matrix
by reactive extrusion grafting of maleic anhydride. Chemical and
mechanical treatment of date wood flour (WF) was conducted to
obtain nanocrystalline cellulose. Layered silicates (clay) were
partially intercalated with date wood fiber, and the modified layered
silicate was used as filler in the PP matrix via a melt-blending
process. The tensile strength of composites prepared from wood fiber
modified clay was greater than that of the iPP-clay and iPP-WF
composites at a 6% filler concentration, whereas deterioration of
mechanical properties was observed when clay and WF were used
alone for reinforcement. The dispersion of the filler in the matrix
significantly decreased after clay modification with cellulose at
higher concentrations, as shown by X-ray diffraction (XRD) data.
Abstract: Proper selection of welding parameters for getting
excellent weld is a challenge. HAZ simulation helps in identifying
suitable welding parameters like heating rate, cooling rate, peak
temperature, and energy input. In this study, the influence of weld
thermal cycle of heat affected zone (HAZ) is simulated for
Submerged Arc Welding (SAW) using Gleeble ® 3800 thermomechanical
simulator. A (Micro-alloyed) MA steel plate of thickness
18 mm having yield strength 450MPa is used for making test
specimens. Determination of the mechanical properties of weld
simulated specimens including Charpy V-notch toughness and
hardness is performed. Peak temperatures of 1300°C, 1150°C,
1000°C, 900°C, 800°C, heat energy input of 22KJ/cm and preheat
temperatures of 30°C have been used with Rykalin-3D simulation
model. It is found that the impact toughness (75J) is the best for the
simulated HAZ specimen at the peak temperature 900ºC. For parent
steel, impact toughness value is 26.8J at -50°C in transverse
direction.
Abstract: Here, we have shown the reaction of [Cr(ArN(CH2)3NAr)2Cl2] (1) where (Ar = 2,6-Pri
2C6H3) and in presence of NaCp (2) (Cp= C5H5 = cyclopentadien), with a center
coordination η5 interaction between Cp as co-ligand and chromium
metal center, for optimization we used density functional theory
(DFT), under methods, explicitly including electrons correlations, for
the final calculations as MB3LYP (Becke) (Lee–Yang–Parr) level of
theory we used to obtain more exact results. This complex was
calculated as electronic energy for molecular system, because the
calculation accounting all electrons correlations interactions. The
optimised of [Cr(ArN(CH2)3NAr)2(η5-Cp)] (Ar = 2,6-Pri2C6H3 and Cp = C5H5) was found to be thermally stable. By using Dewar-Chatt-Duncanson model, as a basis of the molecular orbital (MO) analysis
and showed the highest occupied molecular orbital (HOMO) and
lowest occupied molecular orbital LUMO.
Abstract: Corrosion inhibitors are widely used in concrete
industry to reduce the corrosion rate of steel rebar which is present in
contact with aggressive environments. The present work aims to
using Zamzam water from well located within the Masjid al-Haram
in Mecca, Saudi Arabia 20 m (66 ft) east of the Kaaba, the holiest
place in Islam as corrosion inhibitor for steel in rain water and
simulated acid rain. The effect of Zamzam water was investigated by
electrochemical impedance spectroscopy (EIS) and Potentiodynamic
polarization techniques in Department of Civil Engineering - IUT
Saint-Nazaire, Nantes University, France. Zamzam water is
considered to be one of the most important steel corrosion inhibitor
which is frequently used in different industrial applications. Results
showed that zamzam water gave a very good inhibition for steel
corrosion in rain water and simulated acid rain.
Abstract: The manufacturing technology of band cotton is very
delicate and depends to choice of certain parameters such as torsion
of warp yarn.
The fabric elasticity is achieved without the use of any elastic
material, chemical expansion, artificial or synthetic and it’s capable
of creating pressures useful for therapeutic treatments.
Before use, the band is subjected to treatments of specific
preparation for obtaining certain elasticity, however, during its
treatment, there are some regression parameters. The dependence of
manufacturing parameters on the quality of the chemical treatment
was confirmed.
The aim of this work is to improve the properties of the fabric
through the development of manufacturing technology appropriately.
Finally for the treatment of the strip pancake 100% cotton, a
treatment method is recommended.
Abstract: The discarded clam shell waste, fossil and edible oil
as biolubricant feedstocks create environmental impacts and food
chain dilemma, thus this work aims to circumvent these issues by
using activated saltwater clam shell waste (SCSW) as solid catalyst
for conversion of Jatropha curcas oil as non-edible sources to ester
biolubricant. The characterization of solid catalyst was done by
Differential Thermal Analysis-Thermo Gravimetric Analysis (DTATGA),
X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD),
Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron
Microscopy (FESEM) and Fourier Transformed Infrared
Spectroscopy (FTIR) analysis. The calcined catalyst was used in the
transesterification of Jatropha oil to methyl ester as the first step, and
the second stage was involved the reaction of Jatropha methyl ester
(JME) with trimethylolpropane (TMP) based on the various process
parameters. The formated biolubricant was analyzed using the
capillary column (DB-5HT) equipped Gas Chromatography (GC).
The conversion results of Jatropha oil to ester biolubricant can be
found nearly 96.66%, and the maximum distribution composition
mainly contains 72.3% of triester (TE).
Abstract: Three dimensional non-Interlaced carbon fibre
reinforced silicon carbide (3-D-Cf/SiC) composites with pyrocarbon
interphase were fabricated using isothermal chemical vapor
infiltration (ICVI) combined with polymer impregnation pyrolysis
(PIP) process. Polysilazane (PSZ) is used as a preceramic polymer to
obtain silicon carbide matrix. Thermo gravimetric analysis (TGA),
Infrared spectroscopic analysis (IR) and X-ray diffraction (XRD)
analysis were carried out on PSZ pyrolysed at different temperatures
to understand the pyrolysis and obtaining the optimum pyrolysing
condition to yield β-SiC phase. The density of the composites was
1.94 g cm-3 after the 3-D carbon preform was SiC infiltrated for 280 h
with one intermediate polysilazane pre-ceramic PIP process.
Mechanical properties of the composite materials were investigated
under tensile, flexural, shear and impact loading. The values of
tensile strength were 200 MPa at room temperature (RT) and 195
MPa at 500°C in air. The average RT flexural strength was 243 MPa.
The lower flexural strength of these composites is because of the
porosity. The fracture toughness obtained from single edge notched
beam (SENB) technique was 39 MPa.m1/2. The work of fracture
obtained from the load-displacement curve of SENB test was 22.8
kJ.m-2. The composites exhibited excellent impact resistance and the
dynamic fracture toughness of 44.8 kJ.m-2 is achieved as determined
from instrumented Charpy impact test. The shear strength of the
composite was 93 MPa, which is significantly higher compared 2-D
Cf/SiC composites. Microstructure evaluation of fracture surfaces
revealed the signatures of fracture processes and showed good
support for the higher toughness obtained.
Abstract: Strontium hexaferrite (SrFe12O19; Sr-ferrite) is one of
the well-known materials for permanent magnets. In this study, Mtype
strontium ferrite was prepared by following the conventional
ceramic method from steelmaking by-product. Initial materials;
SrCO3 and by-product, were mixed together in the composition of
SrFe12O19 in different Sr/Fe ratios. The mixtures of these raw
materials were dry-milled for 6h. The blended powder was presintered
(i.e. calcination) at 1000°C for different times periods, then
cooled down to room temperature. These pre-sintered samples were
re-milled in a dry atmosphere for 1h and then fired at different
temperatures in atmospheric conditions, and cooled down to room
temperature. The produced magnetic powder has a dense hexagonal
grain shape structure. The calculated energy product values for the
produced samples ranged from 0.3 to 2.4 MGOe.
Abstract: A phase diagram of the Ag2SO4 - CaSO4 (Silver sulphate – Calcium Sulphate) binaries system using conductivity, XRD (X-Ray Diffraction Technique) and DTA (Differential Thermal Analysis) data is constructed. The eutectic reaction (liquid -» a-Ag2SO4 + CaSO4) is observed at 10 mole% CaSO4 and 645°C. Room temperature solid solubility limit up to 5.27 mole % of Ca 2+ in Ag2SO4 is set using X-ray powder diffraction and scanning electron microscopy results. All compositions beyond this limit are two-phase mixtures below and above the transition temperature (≈ 416°C). The bulk conductivity, obtained following complex impedance spectroscopy, is found decreasing with increase in CaSO4 content. Amongst other binary compositions, the 80AgSO4-20CaSO4 gave improved sinterability/packing density.
Abstract: A vacuum fractionation technique was introduced to remove ethanol from fermentation broth. The effect of initial glucose and ethanol concentrations were investigated for specific productivity. The inhibitory ethanol concentration was observed at 100 g/L. In order to increase the fermentation performance, the ethanol product was removed as soon as it is produced. The broth was boiled at 35oC by reducing the pressure to 65 mBar. The ethanol/water vapor was fractionated for up to 90 wt% before leaving the column. Ethanol concentration in the broth was kept lower than 25 g/L, thus minimized the product inhibition effect to the yeast cells. For batch extractive fermentation, a high substrate utilization rate was obtained at 26.6 g/L.h and most of glucose was consumed within 21 h. For repeated-batch extractive fermentation, addition of glucose was carried out up to 9 times and ethanol was produced more than 8-fold higher than batch fermentation.
Abstract: This research aimed to produce offset printing inks from Samut Songkram’s coconut oil and to test properties of the printing inks comparing with commercial offset printing inks. One of the ingredients in the process of mixing varnish is coconut oil – used to produce black offset printing inks which were the subject of testing issues in order to compare with commercial offset printing inks. Based on the results of research, the best formula for mixing varnish was 50% of coconut oil, 36% of phenolic resin, and 14% of solvent oil. At the same time, the best formula in producing black offset inks was mixing varnish with 20% of coconut oil 20%. Consequently, the result of testing of properties of coconut oil based solvent offset printing inks regarding viscosity, tack and ink flow, showed that offset printing inks with oil based solvent had the properties less than commercial offset printing ink. Additionally, the result of testing also indicate that the rate of properties in aspects of ink spread and setting time of coconut oil based solvent offset printing were higher than that of commercial offset printing inks.
Abstract: Transesterification reactions free of catalyst between
roasted chicken fat with methanol were carried out in a batch reactor
in order to produce biodiesel to temperatures from 120°C to 140°C.
Parameters related to the transesterification reactions, including
temperature, time and the molar ratio of chicken fat to methanol also
investigated. The maximum yield of the reaction was of 98% under
conditions of 140°C, 4 h of reaction time and a molar ratio of chicken
fat to methanol of 1:31. The biodiesel thus obtained exhibited a
viscosity of 6.3 mm2/s and a density of 895.9 kg/m3. The results
showed this process can be right choice to produce biodiesel since
this process does not use any catalyst. Therefore, the steps of
neutralization and washing are avoided, indispensables in the case of
the alkaline catalysis.
Abstract: In the present work the internal sulfate attack on
pastes made from pure clinker phases was studied. Two binders were
produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a
binder with 10% C3A and C4AF content each. Gypsum was used as
the sulfate bearing compound, while calcium carbonate added to
differentiate the binders produced. The phases formed were identified
by XRD analysis. The results showed that ettringite was the
deterioration phase detected in the case of the low C3A content
binder. Carbonation occurred in the specimen without calcium
carbonate addition, while portlandite was observed in the one
containing calcium carbonate. In the case of the high C3A content
binder, traces of thaumasite were detected when calcium carbonate
was not incorporated in the binder. A solid solution of thaumasite and
ettringite was found when calcium carbonate was added. The amount
of C3A had not fully reacted with sulfates, since its corresponding
peaks were detected.
Abstract: Gas flaring is one of the most GHG emitting sources in the oil and gas industries. It is also a major way for wasting such an energy that could be better utilized and even generates revenue. Minimize flaring is an effective approach for reducing GHG emissions and also conserving energy in flaring systems. Integrating waste and flared gases into the fuel gas networks (FGN) of refineries is an efficient tool. A fuel gas network collects fuel gases from various source streams and mixes them in an optimal manner, and supplies them to different fuel sinks such as furnaces, boilers, turbines, etc. In this article we use fuel gas network model proposed by Hasan et al. as a base model and modify some of its features and add constraints on emission pollution by gas flaring to reduce GHG emissions as possible. Results for a refinery case study showed that integration of flare gas stream with waste and natural gas streams to construct an optimal FGN can significantly reduce total annualized cost and flaring emissions.
Abstract: This research project aims to investigate difference in
relative rates concerning phosphoryl transfer relevant to biological
catalysis of DNA and RNA in the pH-independent reactions.
Activated Models of DNA and RNA for alkyl-aryl phosphate diesters
(with 4-nitrophenyl as a good leaving group) have successfully been
prepared to gather kinetic parameters. Eyring plots for the pH–
independent hydrolysis of 1 and 2 were established at different
temperatures in the range 100–160 °C. These measurements have
been used to provide a better estimate for the difference in relative
rates between the reactivity of DNA and RNA cleavage. Eyring plot
gave an extrapolated rate of kH2O = 1 × 10-10 s -1 for 1 (RNA model)
and 2 (DNA model) at 25°C. Comparing the reactivity of RNA
model and DNA model shows that the difference in relative rates in
the pH-independent reactions is surprisingly very similar at 25°. This
allows us to obtain chemical insights into how biological catalysts
such as enzymes may have evolved to perform their current
functions.
Abstract: In the present study, the incorporation of graphene
into blends of acrylonitrile-butadiene-styrene terpolymer with
polypropylene (ABS/PP) was investigated focusing on the
improvement of their thermomechanical characteristics and the effect
on their rheological behavior. The blends were prepared by melt
mixing in a twin-screw extruder and were characterized by measuring
the MFI as well as by performing DSC, TGA and mechanical tests.
The addition of graphene to ABS/PP blends tends to increase their
melt viscosity, due to the confinement of polymer chains motion.
Also, graphene causes an increment of the crystallization temperature
(Tc), especially in blends with higher PP content, because of the
reduction of surface energy of PP nucleation, which is a consequence
of the attachment of PP chains to the surface of graphene through the
intermolecular CH-π interaction. Moreover, the above nanofiller
improves the thermal stability of PP and increases the residue of
thermal degradation at all the investigated compositions of blends,
due to the thermal isolation effect and the mass transport barrier
effect. Regarding the mechanical properties, the addition of graphene
improves the elastic modulus, because of its intrinsic mechanical
characteristics and its rigidity, and this effect is particularly strong in
the case of pure PP.
Abstract: A techno-economic evaluation for efficient use of
energy in a large scale industrial plant of methanol is carried out.
This assessment is based on integration of a gas turbine with an
existing plant of methanol in which the outlet gas products of
exothermic reactor is expanded to power generation. Also, it is
decided that methanol production rate is constant through addition of
power generation system to the existing methanol plant. Having
incorporated a gas turbine with the existing plant, the economic
results showed total investment of MUSD 16.9, energy saving of 3.6
MUSD/yr with payback period of approximately 4.7 years.
Abstract: Li1.5Al0.5Ti1.5 (PO4)3(LATP) has received much
attention as a solid electrolyte for lithium batteries. In this study, the
LATP solid electrolyte is prepared by the co-precipitation method
using Li3PO4 as a Li source. The LATP is successfully prepared and
the Li ion conductivities of bulk (inner crystal) and total (inner crystal
and grain boundary) are 1.1 × 10-3 and 1.1 × 10-4 S cm-1, respectively.
These values are comparable to the reported values, in which Li2C2O4
is used as the Li source. It is conclude that the LATP solid electrolyte
can be prepared by the co-precipitation method using Li3PO4 as the Li
source and this procedure has an advantage in mass production over
previous procedure using Li2C2O4 because Li3PO4 is lower price
reagent compared with Li2C2O4.
Abstract: In this research work, poly (acrylonitrile-butadienestyrene)/
polypropylene (ABS/PP) blends were processed by melt
compounding in a twin-screw extruder. Upgrading of the thermal
characteristics of the obtained materials was attempted by the
incorporation of organically modified montmorillonite (OMMT), as
well as, by the addition of two types of compatibilizers;
polypropylene grafted with maleic anhydride (PP-g-MAH) and ABS
grafted with maleic anhydride (ABS-g-MAH). The effect of the
above treatments was investigated separately and in combination.
Increasing the PP content in ABS matrix seems to increase the
thermal stability of their blend and the glass transition temperature
(Tg) of SAN phase of ABS. From the other part, the addition of ABS
to PP promotes the formation of its β-phase, which is maximum at 30
wt% ABS concentration, and increases the crystallization temperature
(Tc) of PP. In addition, it increases the crystallization rate of PP.The
β-phase of PP in ABS/PP blends is reduced by the addition of
compatibilizers or/and organoclay reinforcement. The incorporation
of compatibilizers increases the thermal stability of PP and reduces
its melting (ΔΗm) and crystallization (ΔΗc) enthalpies. Furthermore it
decreases slightly the Tgs of PP and SAN phases of ABS/PP blends.
Regarding the storage modulus of the ABS/PP blends, it presents a
change in their behavior at about 10°C and return to their initial
behavior at ~110°C. The incorporation of OMMT to no compatibilized
and compatibilized ABS/PP blends enhances their storage modulus.