Abstract: The abundance and availability of rice husk, an agricultural waste, make them as a good source for precursor of activated carbon. In this work, rice husk-based activated carbons were prepared via base treated chemical activation process prior the carbonization process. The effect of carbonization temperatures (400, 600 and 800oC) on their pore structure was evaluated through morphology analysis using scanning electron microscope (SEM). Sample carbonized at 800oC showed better evolution and development of pores as compared to those carbonized at 400 and 600oC. The potential of rice husk-based activated carbon as an alternative adsorbent was investigated for the removal of Ni(II), Zn(II) and Pb(II) from single metal aqueous solution. The adsorption studies using rice husk-based activated carbon as an adsorbent were carried out as a function of contact time at room temperature and the metal ions were analyzed using atomic absorption spectrophotometer (AAS). The ability to remove metal ion from single metal aqueous solution was found to be improved with the increasing of carbonization temperature. Among the three metal ions tested, Pb(II) ion gave the highest adsorption on rice husk-based activated carbon. The results obtained indicate the potential to utilize rice husk as a promising precursor for the preparation of activated carbon for removal of heavy metals.
Abstract: This paper describes the design of a voltage based maximum power point tracker (MPPT) for photovoltaic (PV) applications. Of the various MPPT methods, the voltage based method is considered to be the simplest and cost effective. The major disadvantage of this method is that the PV array is disconnected from the load for the sampling of its open circuit voltage, which inevitably results in power loss. Another disadvantage, in case of rapid irradiance variation, is that if the duration between two successive samplings, called the sampling period, is too long there is a considerable loss. This is because the output voltage of the PV array follows the unchanged reference during one sampling period. Once a maximum power point (MPP) is tracked and a change in irradiation occurs between two successive samplings, then the new MPP is not tracked until the next sampling of the PV array voltage. This paper proposes an MPPT circuit in which the sampling interval of the PV array voltage, and the sampling period have been shortened. The sample and hold circuit has also been simplified. The proposed circuit does not utilize a microcontroller or a digital signal processor and is thus suitable for low cost and low power applications.
Abstract: Ground-level tropospheric ozone is one of the air
pollutants of most concern. It is mainly produced by photochemical
processes involving nitrogen oxides and volatile organic compounds
in the lower parts of the atmosphere. Ozone levels become
particularly high in regions close to high ozone precursor emissions
and during summer, when stagnant meteorological conditions with
high insolation and high temperatures are common.
In this work, some results of a study about urban ozone
distribution patterns in the city of Badajoz, which is the largest and
most industrialized city in Extremadura region (southwest Spain) are
shown. Fourteen sampling campaigns, at least one per month, were
carried out to measure ambient air ozone concentrations, during
periods that were selected according to favourable conditions to
ozone production, using an automatic portable analyzer.
Later, to evaluate the ozone distribution at the city, the measured
ozone data were analyzed using geostatistical techniques. Thus, first,
during the exploratory analysis of data, it was revealed that they were
distributed normally, which is a desirable property for the subsequent
stages of the geostatistical study. Secondly, during the structural
analysis of data, theoretical spherical models provided the best fit for
all monthly experimental variograms. The parameters of these
variograms (sill, range and nugget) revealed that the maximum
distance of spatial dependence is between 302-790 m and the
variable, air ozone concentration, is not evenly distributed in reduced
distances. Finally, predictive ozone maps were derived for all points
of the experimental study area, by use of geostatistical algorithms
(kriging). High prediction accuracy was obtained in all cases as
cross-validation showed. Useful information for hazard assessment
was also provided when probability maps, based on kriging
interpolation and kriging standard deviation, were produced.
Abstract: In this paper we present a photo mosaic smartphone
application in client-server based large-scale image databases. Photo
mosaic is not a new concept, but there are very few smartphone
applications especially for a huge number of images in the
client-server environment. To support large-scale image databases,
we first propose an overall framework working as a client-server
model. We then present a concept of image-PAA features to efficiently
handle a huge number of images and discuss its lower bounding
property. We also present a best-match algorithm that exploits the
lower bounding property of image-PAA. We finally implement an
efficient Android-based application and demonstrate its feasibility.
Abstract: Today, the central role of industrial robots in automation in general and in material handling in particular is crystal clear. Based on the current status of Photovoltaics and by focusing on lightweight material handling, PV industry has turned into a potential candidate for introducing a fresh “pick and place" robot technology. Thus, to examine the industry needs in this regard, firstly the best suited applications for such robotic automation,and then the essential prerequisites in PV industry should be identified. The objective of this paper is to present holistic views on the industry trends, general automation status and existing challenges facing lightweight robotic material handling in PV Silicon Wafer and Thin Film technologies. The results of this study show that currently no uniform pick and place solution prevails among PV Silicon Wafer manufacturers and the industry calls for a new robot solution to satisfy its needs in new directions.
Abstract: A compact 1x3 power splitter based on Photonic
Crystal Waveguides (PCW) with flexible power splitting ratio is
presented in this paper. Multimode interference coupler (MMI) is
integrated with PCW. The device size reduction compared with the
conventional MMI power splitter is attributed to the large dispersion
of the PCW. Band Solve tool is used to calculate the band structure of
PCW. Finite Difference Time Domain (FDTD) method is adopted to
simulate the relevant structure at 1550nm wavelength. The device is
polarization insensitive and allows the control of output (o/p) powers
within certain percentage points for both polarizations.
Abstract: Photovoltaic (PV) systems provides a viable means of
power generation for applications like powering residential
appliances, electrification of villages in rural areas, refrigeration and
water pumping. Photovoltaic-power generation is reliable. The
operation and maintenance costs are very low. Since Myanmar is a
land of plentiful sunshine, especially in central and southern regions
of the country, the solar energy could hopefully become the final
solution to its energy supply problem in rural area.
Abstract: This article presents the developments of efficient
algorithms for tablet copies comparison. Image recognition has
specialized use in digital systems such as medical imaging,
computer vision, defense, communication etc. Comparison between
two images that look indistinguishable is a formidable task. Two
images taken from different sources might look identical but due to
different digitizing properties they are not. Whereas small variation
in image information such as cropping, rotation, and slight
photometric alteration are unsuitable for based matching
techniques. In this paper we introduce different matching
algorithms designed to facilitate, for art centers, identifying real
painting images from fake ones. Different vision algorithms for
local image features are implemented using MATLAB. In this
framework a Table Comparison Computer Tool “TCCT" is
designed to facilitate our research. The TCCT is a Graphical Unit
Interface (GUI) tool used to identify images by its shapes and
objects. Parameter of vision system is fully accessible to user
through this graphical unit interface. And then for matching, it
applies different description technique that can identify exact
figures of objects.
Abstract: The photochemical and photo-Fenton oxidation of 1,3-dichloro-2-propanol was performed in a batch reactor, at room temperature, using UV radiation, H2O2 as oxidant, and Fenton-s reagent. The effect of the oxidative agent-s initial concentration was investigated as well as the effect of the initial concentration of Fe(II) by following the target compound degradation, the total organic carbon removal and the chloride ion production. Also, from the kinetic analysis conducted and proposed reaction scheme it was deduced that the addition of Fe(II) significantly increases the production and the further oxidation of the chlorinated intermediates.
Abstract: Photoselective plastic films with thermic properties
are now available so that greenhouses clad with such plastics exhibit
a higher degree of “Greenhouse Effect” with a consequent increase in
night time temperature. In this study, we investigate the potential
benefits of a range of thermic plastic films used as greenhouse cover
materials on the vegetative and reproductive growth and development
of Iceberg lettuce (Lactuca sativa L). Transplants were grown under
thermic films and destructively harvested 4, 5, and 6 weeks after
transplanting. Thermic films can increase night temperatures up to 2
⁰C reducing the wide fluctuation in greenhouse temperature during
winter compared to the standard commercial film and consequently
increased the yield (leaf number, fresh weight, and dry weight) of
lettuce plants. Lettuce plants grown under Clear film respond to cold
stress by the accumulation of secondary products (phenolics, and
flavonoids).
Abstract: In order to increase in chickpea quality and
agroecosystem sustainability, field experiments were carried out in
2007 and 2008 growing seasons. In this research the effects of
different organic, chemical and biological fertilizers were
investigated on grain yield and quality of chickpea. Experimental
units were arranged in split-split plots based on randomized complete
blocks with three replications. The highest amounts of yield and yield
components were obtained in G1×N5 interaction. Significant
increasing of N, P, K, Fe and Mg content in leaves and grains
emphasized on superiority of mentioned treatment because each one
of these nutrients has an approved role in chlorophyll synthesis and
photosynthesis ability of the crop. The combined application of
compost, farmyard manure and chemical phosphorus (N5) had the
best grain quality due to high protein, starch and total sugar contents,
low crude fiber and reduced cooking time.
Abstract: The elimimation of mefenamic acid has been carried
out by photolysis, ozonation, adsorption onto activated carbon (AC)
and combinations of the previous single systems (O3+AC and
O3+UV). The results obtained indicate that mefenamic acid is not
photo-reactive, showing a relatively low quantum yield of the order
of 6 x 10-4 mol Einstein-1. Application of ozone to mefenamic
aqueous solutions instantaneously eliminates the pharmaceutical,
achieving simultaneously a 40% of mineralization. Addition of AC to
the ozonation process does not enhance the process, moreover,
mineralization is completely inhibited if compared to results obtained
by single ozonation. The combination of ozone and UV radiation led
to the best results in terms of mineralization (60% after 120 min).
Abstract: The photocatalytic activity efficiency of TiO2 for the degradation of Toluene in photoreactor can be enhanced by nano- TiO2/LDPE composite film. Since the amount of TiO2 affected the efficiency of the photocatalytic activity, this work was mainly concentrated on the effort to embed the high amount of TiO2 in the Polyethylene matrix. The developed photocatalyst was characterized by XRD, UV-Vis spectrophotometer and SEM. The SEM images revealed the high homogeneity of the deposition of TiO2 on the polyethylene matrix. The XRD patterns interpreted that TiO2 embedded in the PE matrix exhibited mainly in anatase form. In addition, the photocatalytic results show that the toluene removal efficiencies of 30±5%, 49±4%, 68±5%, 42±6% and 33±5% were obtained when using the catalyst loading at 0%, 10%, 15%, 25% and 50% (wt. cat./wt. film), respectively.
Abstract: The dental composites are preferably used as filling
materials due to their esthetic appearances. Nevertheless one of the
major problems, during the application of the dental composites, is
shape change named as “polymerisation shrinkage" affecting clinical
success of the dental restoration while photo-polymerisation.
Polymerisation shrinkage of composites arises basically from the
formation of a polymer due to the monomer transformation which
composes of an organic matrix phase. It was sought, throughout this
study, to detect and evaluate the structural polymerisation shrinkage
of prepared dental composites in order to optimize the effects of
various fillers included in hydroxyapatite (HA)-reinforced dental
composites and hence to find a means to modify the properties of
these dental composites prepared with defined parameters. As a
result, the shrinkage values of the experimental dental composites
were decreased by increasing the filler content of composites and the
composition of different fillers used had effect on the shrinkage of
the prepared composite systems.
Abstract: This paper presents the applicability of artificial
neural networks for 24 hour ahead solar power generation forecasting
of a 20 kW photovoltaic system, the developed forecasting is suitable
for a reliable Microgrid energy management. In total four neural
networks were proposed, namely: multi-layred perceptron, radial
basis function, recurrent and a neural network ensemble consisting in
ensemble of bagged networks. Forecasting reliability of the proposed
neural networks was carried out in terms forecasting error
performance basing on statistical and graphical methods. The
experimental results showed that all the proposed networks achieved
an acceptable forecasting accuracy. In term of comparison the neural
network ensemble gives the highest precision forecasting comparing
to the conventional networks. In fact, each network of the ensemble
over-fits to some extent and leads to a diversity which enhances the
noise tolerance and the forecasting generalization performance
comparing to the conventional networks.
Abstract: Excilamps are new UV sources with great potential
for application in wastewater treatment. In the present work, a XeBr
excilamp emitting radiation at 283 nm has been used for the
photodegradation of 4-chlorophenol within a range of concentrations
from 50 to 500 mg L-1. Total removal of 4-chlorophenol was
achieved for all concentrations assayed. The two main photoproduct
intermediates formed along the photodegradation process,
benzoquinone and hydroquinone, although not being completely
removed, remain at very low residual concentrations. Such
concentrations are insignificant compared to the 4-chlorophenol
initial ones and non-toxic. In order to simulate the process and scaleup,
a kinetic model has been developed and validated from the
experimental data.
Abstract: Vernonia divergens Benth., commonly known as
“Insulin Plant” (Fam: Asteraceae) is a potent sugar killer. Locally the
leaves of the plant, boiled in water are successfully administered to a
large number of diabetic patients. The present study evaluates the
putative anti-diabetic ingredients, isolated from the in vivo and in
vitro grown plantlets of V. divergens for their antimicrobial and
anticancer activities. Sterilized explants of nodal segments were
cultured on MS (Musashige and Skoog, 1962) medium in presence of
different combinations of hormones. Multiple shoots along with
bunch of roots were regenerated at 1mg l-1 BAP and 0.5 mg l-1 NAA.
Micro-plantlets were separated and sub-cultured on the double
strength (2X) of the above combination of hormones leading to
increased length of roots and shoots. These plantlets were
successfully transferred to soil and survived well in nature. The
ethanol extract of plantlets from both in vivo & in vitro sources were
prepared in soxhlet extractor and then concentrated to dryness under
reduced pressure in rotary evaporator. Thus obtainedconcentrated
extracts showed significant inhibitory activity against gram
negative bacteria like Escherichia coli and Pseudomonas
aeruginosa but no inhibition was found against gram positive
bacteria. Further, these ethanol extracts were screened for in vitro
percentage cytotoxicity at different time periods (24 h, 48 h and 72 h)
of different dilutions. The in vivo plant extract inhibited the growth of
EAC mouse cell lines in the range of 65, 66, 78, and 88% at 100, 50,
25 & 12.5μg mL-1 but at 72 h of treatment. In case of the extract of in
vitro origin, the inhibition was found against EAC cell lines even at
48h. During spectrophotometric scanning, the extracts exhibited
different maxima (ʎ) - four peaks in in vitro extracts as against single
in in vivo preparation suggesting the possible change in the nature of
ingredients during micropropagation through tissue culture
techniques.
Abstract: We present the results of a case study aiming to assess the reflection of the tourism community in the Web and its usability to propose new ways to communicate visually. The wealth of information contained in the Web and the clear facilities to communicate personals points of view makes of the social web a new space of exploration. In this way, social web allow the sharing of information between communities with similar interests. However, the tourism community remains unexplored as is the case of the information covered in travel stories. Along the Web, we find multiples sites allowing the users to communicate their experiences and personal points of view of a particular place of the world. This cultural heritage is found in multiple documents, usually very little supplemented with photos, so they are difficult to explore due to the lack of visual information. This paper explores the possibility of analyzing travel stories to display them visually on maps and generate new knowledge such as patterns of travel routes. This way, travel narratives published in electronic formats can be very important especially to the tourism community because of the great amount of knowledge that can be extracted. Our approach is based on the use of a Geoparsing Web Service to extract geographic coordinates from travel narratives in order to draw the geo-positions and link the documents into a map image.
Abstract: This paper presents a new color face image database
for benchmarking of automatic face detection algorithms and human
skin segmentation techniques. It is named the VT-AAST image
database, and is divided into four parts. Part one is a set of 286 color
photographs that include a total of 1027 faces in the original format
given by our digital cameras, offering a wide range of difference in
orientation, pose, environment, illumination, facial expression and
race. Part two contains the same set in a different file format. The
third part is a set of corresponding image files that contain human
colored skin regions resulting from a manual segmentation
procedure. The fourth part of the database has the same regions
converted into grayscale. The database is available on-line for
noncommercial use. In this paper, descriptions of the database
development, organization, format as well as information needed for
benchmarking of algorithms are depicted in detail.
Abstract: Various solar energy technologies exist and they have
different application techniques in the generation of electrical power.
The widespread use of photovoltaic (PV) modules in such
technologies has been limited by relatively high costs and low
efficiencies. The efficiency of PV panels decreases as the operating
temperatures increase. This is due to the affect of solar intensity and
ambient temperature. In this work, Computational Fluid Dynamics
(CFD) was used to model the heat transfer from a standard PV panel
and thus determine the rate of dissipation of heat. To accurately
model the specific climatic conditions of the United Arab Emirates
(UAE), a case study of a new build green building in Dubai was
used. A finned heat pipe arrangement is proposed and analyzed to
determine the improved heat dissipation and thus improved
performance efficiency of the PV panel. A prototype of the
arrangement is built for experimental testing to validate the CFD
modeling and proof of concept.