Abstract: The combination of the properties of graphene oxide
(OG) and PVDF homopolymer makes their combined composite
materials as multifunctional systems with great potential. Knowledge
of the molecular structure is essential for better use. In this work, the
degradation of PVDF polymer exposed to gamma irradiation in
oxygen atmosphere in high dose rate has been studied and compared
to degradation of PVDF/OG composites. The samples were irradiated
with a Co-60 source at constant dose rate, with doses ranging from
100 kGy to 1,000 kGy. In FTIR data shown that the formation of
oxidation products was at the both samples with formation of
carbonyl and hydroxyl groups amongst the most prevalent products
in the pure PVDF samples. In the other hand, the composites samples
exhibit less presence of degradation products with predominant
formation of carbonyl groups, these results also seen in the UV-Vis
analysis. The results show that the samples of composites may have
greater resistance to the irradiation process, since they have less
degradation products than pure PVDF samples seen by spectroscopic
techniques.
Abstract: Microstructure and fabric of soils play an important
role on structural properties e.g. stiffness and strength of compacted
earthwork. Traditional quality control monitoring based on moisturedensity
tests neither reflects the variability of soil microstructure nor
provides a direct assessment of structural property, which is the
ultimate objective of the earthwork quality control. Since stiffness
and strength are sensitive to soil microstructure and fabric, any
independent test methods that provide simple, rapid, and direct
measurement of stiffness and strength are anticipated to provide an
effective assessment of compacted earthen materials’ uniformity. In
this study, the soil stiffness gauge (SSG) and the dynamic cone
penetrometer (DCP) were respectively utilized to measure and
monitor the stiffness and strength in companion with traditional
moisture-density measurements of various earthen materials used in
Thailand road construction projects. The practical earthwork quality
control criteria are presented herein in order to assure proper
earthwork quality control and uniform structural property of
compacted earthworks.
Abstract: Solar water heating is a thermodynamic process of
heating water using sunlight with the help of solar water heater. Thus,
solar water heater is a device used to harness solar energy. In this
paper, a modified solar water heating system (MSWHS) has been
proposed over flat plate collector (FPC) and Evacuated tube collector
(ETC). The modifications include selection of materials other than
glass, and glass wool which are conventionally used for fabricating
FPC and ETC. Some modifications in design have also been
proposed. Its collector is made of double layer of semi-cylindrical
acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water
tank is made of double layer of acrylic sheet except base and north
wall. FRP is used in base and north wall of the water tank. A concept
of equivalent thickness has been utilised for calculating the
dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed
and simulation is carried out on MATLAB for the capacity of 200L
MSWHS having collector area of 1.6 m2, length of acrylic tubes of
2m at an inclination angle 25° which is taken nearly equal to the
latitude of the given location. Latitude of Allahabad is 24.45° N. The
results show that the maximum temperature of water in tank and tube
has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr
respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying
number of tubes of collector, the tank capacity and climatic data for
given months of winter and summer.
Abstract: The layered structure LiNi1/3Co1/3Mn1/3-xAlxO2 (x = 0 ~
0.04) series cathode materials were synthesized by a carbonate
co-precipitation method, followed by a high temperature calcination
process. The influence of Al substitution on the microstructure and
electrochemical performances of the prepared materials was
investigated by X-Ray diffraction (XRD), scanning electron
microscopy (SEM), and galvanostatic charge/discharge test. The
results show that the LiNi1/3Co1/3Mn1/3-xAlxO2 has a well-ordered
hexagonal α-NaFeO2 structure. Although the discharge capacity of
Al-doped samples decreases as x increases,
LiNi1/3Co1/3Mn1/3-0.02Al0.02O2 exhibits superior capacity retention at
high voltage (4.6 V). Therefore, LiNi1/3Co1/3Mn1/3-0.02Al0.02O2 is a
promising material for “green” vehicles.
Abstract: The irradiation of polymeric materials has received
much attention because it can produce diverse changes in chemical
structure and physical properties. Thus, studying the chemical and
structural changes of polymers is important in practice to achieve
optimal conditions for the modification of polymers. The effect of
gamma irradiation on the crystalline structure of poly(vinylidene
fluoride) (PVDF) has been investigated using differential scanning
calorimetry (DSC) and X-ray diffraction techniques (XRD). Gamma
irradiation was carried out in atmosphere air with doses between 100
kGy at 3,000 kGy with a Co-60 source. In the melting thermogram of
the samples irradiated can be seen a bimodal melting endotherm is
detected with two melting temperature. The lower melting
temperature is attributed to melting of crystals originally present and
the higher melting peak due to melting of crystals reorganized upon
heat treatment. These results are consistent with those obtained by
XRD technique showing increasing crystallinity with increasing
irradiation dose, although the melting latent heat is decreasing.
Abstract: The combination of multi–walled carbon nanotubes
(MWCNTs) with polymers offers an attractive route to reinforce the
macromolecular compounds as well as the introduction of new
properties based on morphological modifications or electronic
interactions between the two constituents. As they are only a few
nanometers in dimension, it offers ultra-large interfacial area per
volume between the nano-element and polymer matrix. Nevertheless,
the use of MWCNTs as a rough material in different applications has
been largely limited by their poor processability, insolubility, and
infusibility. Studies concerning the nanofiller reinforced polymer
composites are justified in an attempt to overcome these limitations.
This work presents one preliminary study of MWCNTs dispersion
into the PVDF homopolymer. For preparation, the composite
components were diluted in n,n-dimethylacetamide (DMAc) with
mechanical agitation assistance. After complete dilution, followed by
slow evaporation of the solvent at 60°C, the samples were dried.
Films of about 80 μm were obtained. FTIR and UV-Vis
spectroscopic techniques were used to characterize the
nanocomposites. The appearance of absorption bands in the FTIR
spectra of nanofilled samples, when compared to the spectrum of
pristine PVDF samples, are discussed and compared with the UV-Vis
measurements.
Abstract: Nowadays, food safety is a great public concern;
therefore, robust and effective techniques are required for detecting
the safety situation of goods. Hyperspectral Imaging (HSI) is an
attractive material for researchers to inspect food quality and safety
estimation such as meat quality assessment, automated poultry
carcass inspection, quality evaluation of fish, bruise detection of
apples, quality analysis and grading of citrus fruits, bruise detection
of strawberry, visualization of sugar distribution of melons,
measuring ripening of tomatoes, defect detection of pickling
cucumber, and classification of wheat kernels. HSI can be used to
concurrently collect large amounts of spatial and spectral data on the
objects being observed. This technique yields with exceptional
detection skills, which otherwise cannot be achieved with either
imaging or spectroscopy alone. This paper presents a nonlinear
technique based on kernel Fukunaga-Koontz transform (KFKT) for
detection of fat content in ground meat using HSI. The KFKT which
is the nonlinear version of FKT is one of the most effective
techniques for solving problems involving two-pattern nature. The
conventional FKT method has been improved with kernel machines
for increasing the nonlinear discrimination ability and capturing
higher order of statistics of data. The proposed approach in this paper
aims to segment the fat content of the ground meat by regarding the
fat as target class which is tried to be separated from the remaining
classes (as clutter). We have applied the KFKT on visible and nearinfrared
(VNIR) hyperspectral images of ground meat to determine
fat percentage. The experimental studies indicate that the proposed
technique produces high detection performance for fat ratio in ground
meat.
Abstract: Reinforced cement concrete is getting extensively used
for construction of different type of structures for the last one century.
During this period, we have constructed many structures like
buildings, bridges, industrial structures, pavement, water tanks etc.
using this construction material. These structures have been created
with huge investment of resources. It is essential to maintain those
structures in functional condition. Since deterioration in RCC
Structures is a common and natural phenomenon it is required to have
a detailed plan, methodology for structural repair and rehabilitation
shall be in place for dealing such issues. It is important to know exact
reason of distress, type of distress and correct method of repair
concrete structures. The different methods of repair are described in
paper according to distress category which can be refereed for repair.
Major finding of the study is that to protect our structure we need to
have maintenance frequency and correct material to be chosen for
repair. Also workmanship during repair needs to be taken utmost care
for quality repair.
Abstract: Ultrasonic metal welding has been the subject of ongoing research and development, most recently concentrating on metal joining in miniature devices, for example to allow solder-free wire bonding. As well as at the small scale, there are also opportunities to research the joining of thicker sheet metals and to widen the range of similar and dissimilar materials that can be successfully joined using this technology. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal spot welding device. The ultrasonic metal spot welding horn is modelled using finite element analysis (FEA) and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered effectively to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. The results show how the weld strength is particularly sensitive to the combination of clamping force and ultrasonic vibration amplitude of the welding tip, but there are optimal combinations of these and also limits that must be clearly identified.
Abstract: A composite material with carbon fiber and polymer
matrix has been used as adherent for manufacturing adhesive joints.
In order to evaluate different fiber orientations on joint performance,
the adherents with the 0°, ±15°, ±30°, ±45° fiber orientations were
used in the single lap joint configuration. The joints with an overlap
length of 25 mm were prepared according to the ASTM 1002
specifications and subjected to tensile loadings. The structural
adhesive used was a two-part epoxy to be cured at 70°C for an hour.
First, mechanical behaviors of the adherents were measured using
three point bending test. In the test, considerations were given to
stress to failure and elastic modulus. The results were compared with
theoretical ones using rule of mixture. Then, the joints were
manufactured in a specially prepared jig, after a proper surface
preparation. Experimental results showed that the fiber orientations
of the adherents affected the joint performance considerably; the
joints with ±45° adherents experienced the worst shear strength, half
of those with 0° adherents, and in general, there was a great
relationship between the fiber orientations and failure mechanisms.
Delamination problems were observed for many joints, which were
thought to be due to peel effects at the ends of the overlap. It was
proved that the surface preparation applied to the adherent surface
was adequate. For further explanation of the results, a numerical
work should be carried out using a possible non-linear analysis.
Abstract: This paper investigates the application of metallic
coatings on high fiber volume fraction carbon/epoxy polymer matrix
composites. For the grip of the metallic layer, a method of modifying
the surface of the composite by introducing a mixture of copper and
steel powder (filler powders) which can reduce the impact of thermal
spray particles. The powder was introduced to the surface at the time
of the forming. Arc spray was used to project the zinc coating layer.
The substrate was grit blasted to avoid poor adherence. The porosity, microstructure, and morphology of layers are
characterized by optical microscopy, SEM and image analysis. The
samples were studied also in terms of hardness and erosion resistance.
This investigation did not reveal any visible evidence damage to the
substrates. The hardness of zinc layer was about 25.94 MPa and the
porosity was around (∼6.70%). The erosion test showed that the zinc
coating improves the resistance to erosion. Based on the results
obtained, we can conclude that thermal spraying allows the production
of protective coating on PMC. Zinc coating has been identified as a
compatible material with the substrate. The filler powders layer
protects the substrate from the impact of hot particles and allows
avoiding the rupture of brittle carbon fibers.
Abstract: The present paper examines the impact noise
transmission through some floor building assemblies. The Acoubat
software numerical simulation has been used to simulate the impact
noise transmission through different floor configurations used in
Algerian construction mode. The results are compared with the
available measurements. We have developed two experimental
methods, i) field method, and ii) laboratory method using Brüel and
Kjær equipments. The results show that the different cases of floor
configurations need some improvement to ensure the acoustic
comfort in the receiving apartment. The recommended value of the
impact sound level in the receiving room should not exceed 58 dB.
The important results obtained in this paper can be used as platform
to improve the Algerian building acoustic regulation aimed at the
construction of the multi-storey residential building.
Abstract: The Hall Coefficient (HC) and the Magnetoresistance (MR) have been studied in two-dimensional systems. The HC and the MR in Rectangular Quantum Wire (RQW) subjected to a crossed DC electric field and magnetic field in the presence of a Strong Electromagnetic Wave (EMW) characterized by electric field are studied in this work. Using the quantum kinetic equation for electrons interacting with optical phonons, we obtain the analytic expressions for the HC and the MR with a dependence on magnetic field, EMW frequency, temperatures of systems and the length characteristic parameters of RQW. These expressions are different from those obtained for bulk semiconductors and cylindrical quantum wires. The analytical results are applied to GaAs/GaAs/Al. For this material, MR depends on the ratio of the EMW frequency to the cyclotron frequency. Indeed, MR reaches a minimum at the ratio 5/4, and when this ratio increases, it tends towards a saturation value. The HC can take negative or positive values. Each curve has one maximum and one minimum. When magnetic field increases, the HC is negative, achieves a minimum value and then increases suddenly to a maximum with a positive value. This phenomenon differs from the one observed in cylindrical quantum wire, which does not have maximum and minimum values.
Abstract: With 40% of total world energy consumption,
building systems are developing into technically complex large
energy consumers suitable for application of sophisticated power
management approaches to largely increase the energy efficiency
and even make them active energy market participants. Centralized
control system of building heating and cooling managed by
economically-optimal model predictive control shows promising
results with estimated 30% of energy efficiency increase. The research
is focused on implementation of such a method on a case study
performed on two floors of our faculty building with corresponding
sensors wireless data acquisition, remote heating/cooling units and
central climate controller. Building walls are mathematically modeled
with corresponding material types, surface shapes and sizes. Models
are then exploited to predict thermal characteristics and changes in
different building zones. Exterior influences such as environmental
conditions and weather forecast, people behavior and comfort
demands are all taken into account for deriving price-optimal climate
control. Finally, a DC microgrid with photovoltaics, wind turbine,
supercapacitor, batteries and fuel cell stacks is added to make the
building a unit capable of active participation in a price-varying
energy market. Computational burden of applying model predictive
control on such a complex system is relaxed through a hierarchical
decomposition of the microgrid and climate control, where the
former is designed as higher hierarchical level with pre-calculated
price-optimal power flows control, and latter is designed as lower
level control responsible to ensure thermal comfort and exploit
the optimal supply conditions enabled by microgrid energy flows
management. Such an approach is expected to enable the inclusion
of more complex building subsystems into consideration in order to
further increase the energy efficiency.
Abstract: The application of recycle waste tires into civil
engineering practices, namely asphalt paving mixtures and cementbased
materials has been gaining ground across the world. This
review summarizes and compares the recent achievements in the area
of plain rubberized concrete (PRC), in details. Different treatment
methods have been discussed to improve the performance of
rubberized Portland cement concrete. The review also includes the
effects of size and amount of tire rubbers on mechanical and
durability properties of PRC. The microstructure behaviour of the
rubberized concrete was detailed.
Abstract: With the strengthened regulation on the mandatory use
of recycled aggregate, development of construction materials using
recycled aggregate has recently increased. This study aimed to secure
the performance of asphalt concrete mixture by developing
recycled-modified asphalt using recycled basalt aggregate from the
Jeju area. The strength of the basalt aggregate from the Jeju area used
in this study was similar to that of general aggregate, while the specific
surface area was larger due to the development of pores. Modified
asphalt was developed using a general aggregate-recycled aggregate
ratio of 7:3, and the results indicated that the Marshall stability
increased by 27% compared to that of asphalt concrete mixture using
only general aggregate, and the flow values showed similar levels.
Also, the indirect tensile strength increased by 79%, and the toughness
increased by more than 100%. In addition, the TSR for examining
moisture resistance was 0.95 indicating that the reduction in the
indirect tensile strength due to moisture was very low (5% level), and
the developed recycled-modified asphalt could satisfy all the quality
standards of asphalt concrete mixture.
Abstract: Medicinal and aromatic plants are promising and are characterized by the biosynthesis of odorous molecules that make up the so-called essential oils (EO), which have long been known for their antiseptic and therapeutic activity in folk medicine. Essential oils have many therapeutic properties. In herbal medicine, they are used for their antiseptic properties against infectious diseases of fungal origin, against dermatophytes, those of bacterial origin. The objective of this study was to evaluate the influence of drying in the shade on the water content and on the content of essential oils extracted from leaves of Eucalyptus camendulensis for better quality control of medicinal and aromatic plants. The water content of the Eucalyptus camendulensis plant material decreases during the drying process. It decreased from 100% to 0.006% for the drying in the shade after ten days. The moisture content is practically constant at the end of the drying period. The drying in the shade increases the concentration of essential oils of Eucalyptus camendulensis. When the leaves of Eucalyptus camendulensis plant are in the shade, the maximum of the essential oil content was obtained on the eighth day, the recorded value was 1.43% ± 0.01%. Beyond these periods, the content continuously drop in before stabilizing. The optimum drying time is between 6 and 9 days.
Abstract: Some of the main causes for degradation of polymeric materials are thermal aging, hydrolysis, oxidation or chemical degradation by acids, alkalis or water. The first part of this paper provides a brief summary of advances in technology, methods and specification of composite materials for relining as a rehabilitation technique for sewage systems. The second part summarizes an investigation on frequently used composite materials for relining in Sweden, the rubber filled epoxy composite and reinforced polyester composite when they were immersed in deionized water or in dry conditions, and elevated temperatures up to 80°C in the laboratory. The tests were conducted by visual inspection, microscopy, Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) as well as mechanical testing, three point bending and tensile testing.
Abstract: The present study investigates the effectiveness of
newly designed clayey pellets (fired clay pellets diameter sizes of 5
and 8 mm, and unfired clay pellets with the diameter size of 15 mm)
as the beds in the column adsorption process. The adsorption
experiments in the batch mode were performed before the column
experiment with the purpose to determine the order of adsorbent
package in the column which was to be designed in the investigation.
The column experiment was performed by using a known mass of the
clayey beds and the volume of the waste printing developer, which
was purified. The column was filled in the following order: fired clay
pellets of the diameter size of 5 mm, fired clay pellets of the diameter
size of 8 mm, and unfired clay pellets of the diameter size of 15 mm.
The selected order of the adsorbents showed a high removal
efficiency for zinc (97.8%) and copper (81.5%) ions. These
efficiencies were better than those in the case of the already existing
mode adsorption. The obtained experimental data present a good
basis for the selection of an appropriate column fill, but further
testing is necessary in order to obtain more accurate results.
Abstract: Landfill waste is a common problem as it has an
economic and environmental impact even if it is closed. Landfill
waste contains a high density of various persistent compounds such
as heavy metals, organic and inorganic materials. As persistent
compounds are slowly-degradable or even non-degradable in the
environment, they often produce sublethal or even lethal effects on
aquatic organisms. The aims of the present study were to estimate
sublethal effects of the Kairiai landfill (WGS: 55°55‘46.74“,
23°23‘28.4“) leachate on the locomotor activity of rainbow trout
Oncorhynchus mykiss juveniles using the original system package
developed in our laboratory for automated monitoring, recording and
analysis of aquatic organisms’ activity, and to determine patterns of
fish behavioral response to sublethal effects of leachate. Four
different concentrations of leachate were chosen: 0.125; 0.25; 0.5 and
1.0 mL/L (0.0025; 0.005; 0.01 and 0.002 as part of 96-hour LC50,
respectively). Locomotor activity was measured after 5, 10 and 30
minutes of exposure during 1-minute test-periods of each fish (7 fish
per treatment). The threshold-effect-concentration amounted to 0.18
mL/L (0.0036 parts of 96-hour LC50). This concentration was found
to be even 2.8-fold lower than the concentration generally assumed to
be “safe” for fish. At higher concentrations, the landfill leachate
solution elicited behavioral response of test fish to sublethal levels of
pollutants. The ability of the rainbow trout to detect and avoid
contaminants occurred after 5 minutes of exposure. The intensity of
locomotor activity reached a peak within 10 minutes, evidently
decreasing after 30 minutes. This could be explained by the
physiological and biochemical adaptation of fish to altered
environmental conditions. It has been established that the locomotor
activity of juvenile trout depends on leachate concentration and
exposure duration. Modeling of these parameters showed that the
activity of juveniles increased at higher leachate concentrations, but
slightly decreased with the increasing exposure duration. Experiment
results confirm that the behavior of rainbow trout juveniles is a
sensitive and rapid biomarker that can be used in combination with
the system for fish behavior monitoring, registration and analysis to
determine sublethal concentrations of pollutants in ambient water.
Further research should be focused on software improvement aimed
to include more parameters of aquatic organisms’ behavior and to
investigate the most rapid and appropriate behavioral responses in
different species. In practice, this study could be the basis for the
development and creation of biological early-warning systems
(BEWS).