Abstract: This study presents an attempt to evaluate the
antioxidant potential and antimicrobial activity of methanolic extract,
and essential oils prepared from the leaves of sage (Salvia officinalis
L.). The content of polyphenol in the methanolic extracts from the
leaves of Salvia officinalis was determined spectrophotometrically,
calculated as gallic acid and catechin equivalent. The essential oils
and methanol extract were also subjected to screenings for the
evaluation of their antioxidant activities using 2, 2-diphenyl-1-
picrylhydrazyl (DPPH) test. While the plant essential oils showed
only weak antioxidant activities, its methanol extract was
considerably active in DPPH (IC50 = 37.29 μg/ml) test. Appreciable
total polyphenol content (31.25 mg/g) was also detected for the plant
methanol extract as gallic acid equivalent in the Folin–Ciocalteu test.
The plant was also screened for its antimicrobial activity and good to
moderate inhibitions were recorded for its essential oils, and
methanol extracts against most of the tested microorganisms.
The present investigation revealed that this plant had rich source
of antioxidant properties. It is for this reason that sage has found
increasing application in food formulations.
Abstract: Monocopter is a single-wing rotary flying vehicle
which has the capability of hovering. This flying vehicle includes two
dynamic parts in which more efficiency can be expected rather than
other Micro UAVs due to the extended area of wing compared to its
fuselage. Low cost and simple mechanism in comparison to other
vehicles such as helicopter are the most important specifications of
this flying vehicle.
In the previous paper we discussed the introduction of the final
system but in this paper, the experimental design process of
Monocopter and its control algorithm has been investigated in
general. Also the editorial bugs in the previous article have been
corrected and some translational ambiguities have been resolved.
Initially by constructing several prototypes and carrying out many
flight tests the main design parameters of this air vehicle were
obtained by experimental measurements. Eventually the required
main monocopter for this project was constructed. After construction
of the monocopter in order to design, implementation and testing of
control algorithms first a simple optic system used for determining
the heading angle. After doing numerous tests on Test Stand, the
control algorithm designed and timing of applying control inputs
adjusted. Then other control parameters of system were tuned in
flight tests. Eventually the final control system designed and
implemented using the AHRS sensor and the final operational tests
performed successfully.
Abstract: We report on the use of strong external optical
feedback to enhance the modulation response of semiconductor lasers
over a frequency passband around modulation frequencies higher
than 60 GHz. We show that this modulation enhancement is a type of
photon-photon resonance (PPR) of oscillating modes in the external
cavity formed between the laser and the external reflector. The study
is based on a time-delay rate equation model that takes into account
both the strong feedback and multiple reflections in the external
cavity. We examine the harmonic and intermodulation distortions
associated with single and two-tone modulations in the mm-wave
band of the resonant modulation. We show that compared with
solitary lasers modulated around the carrier-photon resonance
frequency, the present mm-wave modulated signal has lower
distortions.
Abstract: The electric power supplied by a photovoltaic power
generation systems depends on the solar irradiation and temperature.
The PV system can supply the maximum power to the load at a
particular operating point which is generally called as maximum
power point (MPP), at which the entire PV system operates with
maximum efficiency and produces its maximum power. Hence, a
Maximum power point tracking (MPPT) methods are used to
maximize the PV array output power by tracking continuously the
maximum power point. The proposed MPPT controller is designed
for 10kW solar PV system installed at Cape Institute of Technology.
This paper presents the fuzzy logic based MPPT algorithm. However,
instead of one type of membership function, different structures of
fuzzy membership functions are used in the FLC design. The
proposed controller is combined with the system and the results are
obtained for each membership functions in Matlab/Simulink
environment. Simulation results are decided that which membership
function is more suitable for this system.
Abstract: Due to the determination of the pollution status of
fresh resources in the Egyptian territorial waters is very important for
public health; this study was carried out to reveal the levels of heavy
metals in the shellfish and their environment and its relation to the
highly developed industrial activities in those areas. A total of 100
shellfish samples from the Rosetta, Edku, El-Maadiya, Abo-Kir and
El-Max coasts [10 crustaceans (shrimp) and 10 mollusks (oysters)]
were randomly collected from each coast. Additionally, 10 samples
from both the water and the sediment were collected from each coast.
Each collected sample was analyzed for cadmium, chromium,
copper, lead and zinc residues using a Perkin Elmer atomic
absorption spectrophotometer (AAS). The results showed that the
levels of heavy metals were higher in the water and sediment from
Abo-Kir. The heavy metal levels decreased successively for the
Rosetta, Edku, El-Maadiya, and El-Max coasts, and the
concentrations of heavy metals, except copper and zinc, in shellfish
exhibited the same pattern. For the concentration of heavy metals in
shellfish tissue, the highest was zinc and the concentrations decreased
successively for copper, lead, chromium and cadmium for all coasts,
except the Abo-Kir coast, where the chromium level was highest and
the other metals decreased successively for zinc, copper, lead and
cadmium. In Rosetta, chromium was higher only in the mollusks,
while the level of this metal was lower in the crustaceans; this trend
was observed at the Edku, El-Maadiya and El-Max coasts as well.
Herein, we discuss the importance of such contamination for public
health and the sources of shellfish contamination with heavy metals.
We suggest measures to minimize and prevent these pollutants in the
aquatic environment and, furthermore, how to protect humans from
excessive intake.
Abstract: Nitrogen-doped graphene quantum dots (N-GQDs)
were fabricated by microwave-assisted hydrothermal technique. The
optical properties of the N-GQDs were studied. The luminescence of
the N-GQDs can be tuned by varying the excitation wavelength.
Furthermore, two-photon luminescence of the N-GQDs excited by
near-infrared laser can be obtained. It is shown that N-doping play a
key role on two-photon luminescence. The N-GQDs are expected to
find application in biological applications including bioimaging and
sensing.
Abstract: This paper presents a study on Proportional Resonant
(PR) current control with additional PR harmonic compensators for
Grid Connected Photovoltaic (PV) Inverters. Both simulation and
experimental results will be presented. Testing was carried out on a
3kW Grid-Connected PV Inverter which was designed and
constructed for this research.
Abstract: Hydrogenated amorphous carbon (a-C:H) films have
been synthesized by a radio frequency plasma enhanced chemical
vapor deposition (rf-PECVD) technique with different bias voltage
from 0.0 to -0.5 kV. The Raman spectra displayed the polymer-like
hydrogenated amorphous carbon (PLCH) film with 0.0 to -0.1 and
a-C:H films with -0.2 to -0.5 kV of bias voltages. The surface chemical
information of all films were studied by X-ray photoelectron
spectroscopy (XPS) technique, presented to C-C (sp2 and sp3) and C-O
bonds, and relative carbon (C) and oxygen (O) atomics contents. The
O contamination had affected on structure and optical properties. The
true density of PLCH and a-C:H films were characterized by X-ray
refractivity (XRR) method, showed the result as in the range of
1.16-1.73 g/cm3 that depending on an increasing of bias voltage. The
hardness was proportional to the true density of films. In addition, the
optical properties i.e. refractive index (n) and extinction coefficient (k)
of these films were determined by a spectroscopic ellipsometry (SE)
method that give formation to in 1.62-2.10 (n) and 0.04-0.15 (k)
respectively. These results indicated that the optical properties
confirmed the Raman results as presenting the structure changed with
applied bias voltage increased.
Abstract: Renewable energy is derived from natural processes
that are replenished constantly. Included in the definition is
electricity and heat generated from solar, wind, ocean, hydropower,
biomass, geothermal resources, and bio-fuels and hydrogen derived
from renewable resources. Each of these sources has unique
characteristics which influence how and where they are used. This
paper presents the modeling the simulation of solar and hydro hybrid
energy sources in MATLAB/SIMULINK environment. It simulates
all quantities of Hybrid Electrical Power system (HEPS) such as AC
output current of the inverter that injected to the load/grid, load
current, grid current. It also simulates power output from PV and
Hydraulic Turbine Generator (HTG), power delivered to or from grid
and finally power factor of the inverter for PV, HTG and grid. The
proposed circuit uses instantaneous p-q (real-imaginary) power
theory.
Abstract: In the present study, we have synthesized Cr and Fe
doped zinc oxide (ZnO) nanostructures (Zn1-δCraFebO; where δ = a +
b = 20%, a = 5, 6, 8 & 10% and b = 15, 14, 12 & 10%) via sol-gel
method at different doping concentrations. The synthesized samples
were characterized for structural properties by X-ray diffractrometer
and field emission scanning electron microscope and the optical
properties were carried out through photoluminescence and UVvisible
spectroscopy. The particle size calculated through field
emission scanning electron microscope varies from 41 to 96 nm for
the samples synthesized at different doping concentrations. The
optical band gaps calculated through UV-visible spectroscopy are
found to be decreasing from 3.27 to 3.02 eV as the doping
concentration of Cr increases and Fe decreases.
Abstract: Ongoing landscape transformation is one of the major
causes behind disappearance of traditional landscapes, and lead to
species and resource loss. Tree in paddy fields in the northeast of
Thailand is one of those traditional landscapes. Using three different
historical time layers, we acknowledged the severe deforestation and
rapid urbanization happened in the region. Despite the general
thinking of decline in tree density as consequences, the heterogeneous
trend of changes in total tree density in three studied landscapes denied
the hypothesis that number of trees in paddy field depend on the length
of land use practice. On the other hand, due to selection of planting
new trees on levees, existence of trees in paddy field now relies on
their values for human use. Besides, changes in land use and landscape
structure had a significant impact on decision of which tree density
level is considered as suitable for the landscape.
Abstract: This paper presents a model predictive control (MPC)
of a utility interactive (UI) single phase inverter (SPI) for a
photovoltaic (PV) system at residential/distribution level. The
proposed model uses single-phase phase locked loop (PLL) to
synchronize SPI with the grid and performs MPC control in a dq
reference frame. SPI model consists of boost converter (BC),
maximum power point tracking (MPPT) control, and a full bridge
(FB) voltage source inverter (VSI). No PI regulators to tune and
carrier and modulating waves are required to produce switching
sequence. Instead, the operational model of VSI is used to synthesize
sinusoidal current and track the reference. Model is validated using a
three kW PV system at the input of UI-SPI in Matlab/Simulink.
Implementation and results demonstrate simplicity and accuracy, as
well as reliability of the model.
Abstract: Advances technology in the field of photogrammetry
replaces analog cameras with reflection on aircraft GPS/IMU system
with a digital aerial camera. In this system, when determining the
position of the camera with the GPS, camera rotations are also
determined by the IMU systems. All around the world, digital aerial
cameras have been used for the photogrammetry applications in the
last ten years. In this way, in terms of the work done in
photogrammetry it is possible to use time effectively, costs to be
reduced to a minimum level, the opportunity to make fast and
accurate.
Geo-referencing techniques that are the cornerstone of the GPS /
INS systems, photogrammetric triangulation of images required for
balancing (interior and exterior orientation) brings flexibility to the
process. Also geo-referencing process; needed in the application of
photogrammetry targets to help to reduce the number of ground
control points. In this study, the use of direct and indirect georeferencing
techniques on the accuracy of the points was investigated
in the production of photogrammetric mapping.
Abstract: Metal-enhanced Luminescence of silicon nanocrystals
(SiNCs) was determined using two different particle sizes of silver
nanoparticles (AgNPs). SiNCs have been characterized by scanning
electron microscopy (SEM), high resolution transmission electron
microscopy (HRTEM), Fourier transform infrared spectroscopy
(FTIR) and X-ray photoelectron spectroscopy (XPS). It is found that
the SiNCs are crystalline with an average diameter of 65 nm and FCC
lattice. AgNPs were synthesized using photochemical reduction of
AgNO3 with sodium dodecyl sulphate (SDS). The enhanced
luminescence of SiNCs by AgNPs was evaluated by confocal Raman
microspectroscopy. Enhancement up to x9 and x3 times were
observed for SiNCs that mixed with AgNPs which have an average
particle size of 100 nm and 30 nm, respectively. Silver NPs-enhanced
luminescence of SiNCs occurs as a result of the coupling between the
excitation laser light and the plasmon bands of AgNPs; thus this
intense field at AgNPs surface couples strongly to SiNCs.
Abstract: The mathematical analysis on radiation obtained and
the development of the solar photovoltaic (PV) array groundwater
pumping is needed in the rural areas of Thohoyandou for sizing and
power performance subject to the climate conditions within the area.
A simple methodology approach is developed for the directed
coupled solar, controller and submersible ground water pump system.
The system consists of a PV array, pump controller and submerged
pump, battery backup and charger controller. For this reason, the
theoretical solar radiation is obtained for optimal predictions and
system performance in order to achieve different design and
operating parameters. Here the examination of the PV schematic
module in a Direct Current (DC) application is used for obtainable
maximum solar power energy for water pumping. In this paper, a
simple efficient photovoltaic water pumping system is presented with
its theoretical studies and mathematical modeling of photovoltaics
(PV) system.
Abstract: This study focuses on the cooling of a photovoltaic
panel (PV). Indeed, the cooling improves the conversion capacity of
this one and maintains, under extreme conditions of air temperature,
the panel temperature at an appreciable level which avoids the
altering. To do this, a fan provides forced circulation of air. Because
the fan is supplied by the panel, it is necessary to determine the
optimum operating point that unites efficiency of the PV with the
consumption of the fan. For this matter, numerical simulations are
performed at varying mass flow rates of air, under two extreme air
temperatures (50°C, 25°C) and a fixed solar radiation (1000W.m2) in
a case of no wind.
Abstract: Pollution of the Klip River has caused
microorganisms inhabiting it to develop protective survival
mechanisms. This study isolated and characterized the heavy metal
resistant bacteria in the Klip River. Water and sediment samples were
collected from six sites along the course of the river. The pH,
turbidity, salinity, temperature and dissolved oxygen were measured
in-situ. The concentrations of six heavy metals (Cd, Cu, Fe, Ni, Pb
and Zn) of the water samples were determined by atomic absorption
spectroscopy. Biochemical and antibiotic profiles of the isolates were
assessed using the API 20E® and Kirby Bauer Method. Growth
studies were carried out using spectrophotometric methods. The
isolates were identified using 16SrDNA sequencing. The uppermost
part of the Klip River with the lowest pH had the highest levels of
heavy metals. Turbidity, salinity and specific conductivity increased
measurably at Site 4 (Henley on Klip Weir). MIC tests showed that
16 isolates exhibited high iron and lead resistance. Antibiotic
susceptibility tests revealed that the isolates exhibited multitolerances
to drugs such as Tetracycline, Ampicillin, and
Amoxicillin.
Abstract: A simple, accurate and precise direct spectrophotometric method has been developed for the determination of cefixime in tablets and capsules. The method is based on the reaction of cefixime with a mixture of potassium iodide and potassium iodate to form yellow coloured product in ethanol-distilled water medium at room temperature which absorbed maximally at 352 nm. The factors affecting the reaction product were carefully studied and optimized. The validation parameters based on International Conference on Harmonisation (ICH, USA) guidelines were followed. The effect of common excipients used as additives has been tested and the tolerance limit was calculated for the determination of cefixime. Beer’s law is obeyed in the concentration range of 4 – 24 ug mL-1 with apparent molar absorptivity of 1.52 × 104 L mol-1cm-1 and Sandell’s sensitivity of 0.033 ug/cm2/ 0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.32 and 1.06 ug mL-1, respectively. The proposed method has been successfully applied for the determination of cefixime in pharmaceutical formulations. The results obtained by the proposed method were statistically compared with the reference method using t- and F- values and found no significant difference between the two methods. The proposed method can be used as an alternate method for routine quality control analysis of cefixime in pharmaceutical formulations.
Abstract: In development of floating photovoltaic generation
system, finding a suitable place of installation is as important as
development of economically feasible and stable structure. Especially
since floating photovoltaic system has its facility floating on water
surface, it is extremely important to review the effects of weather
conditions such as wind, water flow and floating matters, various
factors (such as fogs) that can reduce generation efficiency, possibility
of connection with power system, and legal restrictions. The method of
investigating suitable area and resource for development of
tracking-type floating photovoltaic generation system was proposed in
this paper, which can be used for development of floating and ocean
photovoltaic system in the future.
Abstract: This research proposes a novel reconstruction protocol
for restoring missing surfaces and low-quality edges and shapes in
photos of artifacts at historical sites. The protocol starts with the
extraction of a cloud of points. This extraction process is based on
four subordinate algorithms, which differ in the robustness and
amount of resultant. Moreover, they use different -but
complementary- accuracy to some related features and to the way
they build a quality mesh. The performance of our proposed protocol
is compared with other state-of-the-art algorithms and toolkits. The
statistical analysis shows that our algorithm significantly outperforms
its rivals in the resultant quality of its object files used to reconstruct
the desired model.