Abstract: This study was conducted to formulate diclofenac sodium-loaded chitosan nanoparticles and to study the effect of formulation compositions on particle size and zeta potential of chitosan nanoparticles (CSN) containing diclofenac sodium (DC) prepared by ionotropic gelation method. It was found that the formulations containing chitosan, DC and tripolyphosphate (TPP) at a weight ratio of 4:1:1, respectively, with various pH provided various systems. At pH 5.0 and 6.0, the obtained systems were turbid because of precipitation of DC and chitosan, respectively. However, the dispersed system of CSN possessing diameter of 108±1 nm and zeta potential of 19±1 mV could be obtained at pH 5.5. These CSN also showed spherical morphology observed via a transmission scanning electron microscope. Change in weight ratio of chitosan:DC:TPP i.e. 1:1:1, 2:1:1, 3:1:1 and 4:1:1 showed that these ratios led to precipitation of particles except for the ratio of 4:1:1 providing CSN properly. The effect of Tween 80 as a stabilizer was also determined. It suggested that increment of Tween 80 concentration to 0.02% w/v could stabilize CSN at least 48 hours. However, increment of Tween 80 to 0.03% w/v led to quick precipitation of particles. The study of effect of TPP suggested that increment of TPP concentration increased particle size but decreased zeta potential. The excess TPP caused precipitation of CSN. Therefore, the optimized CSN was the CSN containing chitosan, DC and TPP at the ratio of 4:1:1and 0.02% w/v Tween 80 prepared at pH 5.5. Their particle size, zeta potential and entrapment efficiency were 128±1 nm, 15±1 mV and 45.8±2.6%, respectively.
Abstract: Exposure to ambient air pollution has been linked to a
number of health outcomes, starting from modest transient changes in
the respiratory tract and impaired pulmonary function, continuing to
restrict activity/reduce performance and to the increase emergency
rooms visits, hospital admissions or mortality. The increase of
allergenic symptoms has been associated with air contaminants such
as ozone, particulate matter, fungal spores and pollen.
Considering the potential relevance of crossed effects of nonbiological
pollutants and airborne pollens and fungal spores on
allergy worsening, the aim of this work was to evaluate the influence
of non-biological pollutants (O3 and PM10) and meteorological
parameters on the concentrations of pollen and fungal spores using
multiple linear regressions.
The data considered in this study were collected in Oporto which
is the second largest Portuguese city, located in the North. Daily
mean of O3, PM10, pollen and fungal spore concentrations,
temperature, relative humidity, precipitation, wind velocity, pollen
and fungal spore concentrations, for 2003, 2004 and 2005 were
considered. Results showed that the 90th percentile of the adjusted
coefficient of determination, P90 (R2aj), of the multiple regressions
varied from 0.613 to 0.916 for pollen and from 0.275 to 0.512 for
fungal spores. O3 and PM10 showed to have some influence on the
biological pollutants. Among the meteorological parameters
analysed, temperature was the one that most influenced the pollen
and fungal spores airborne concentrations. Relative humidity also
showed to have some influence on the fungal spore dispersion.
Nevertheless, the models for each pollen and fungal spore were
different depending on the analysed period, which means that the
correlations identified as statistically significant can not be, even so,
consistent enough.
Abstract: Microbial-induced calcite precipitation (MICP) is a
relatively green and sustainable soil improvement technique. It
utilizes biochemical process that exists naturally in soil to improve
engineering properties of soils. The calcite precipitation process is
uplifted by the mean of injecting higher concentration of urease
positive bacteria and reagents into the soil. The main objective of this
paper is to provide an overview of the factors affecting the MICP in
soil. Several factors were identified including nutrients, bacteria type,
geometric compatibility of bacteria, bacteria cell concentration,
fixation and distribution of bacteria in soil, temperature, reagents
concentration, pH, and injection method. These factors were found to
be essential for promoting successful MICP soil treatment.
Furthermore, a preliminary laboratory test was carried out to
investigate the potential application of the technique in improving the
shear strength and impermeability of a residual soil specimen. The
results showed that both shear strength and impermeability of
residual soil improved significantly upon MICP treatment. The
improvement increased with increasing soil density.
Abstract: Treatment of tar-containing wastewater is necessary
for the successful operation of biomass gasification plants (BGPs). In
the present study, tar-containing wastewater was treated using lime
and alum for the removal of in-organics, followed by adsorption on
powdered activated carbon (PAC) for the removal of organics. Limealum
experiments were performed in a jar apparatus and activated
carbon studies were performed in an orbital shaker. At optimum
concentrations, both lime and alum individually proved to be capable
of removing color, total suspended solids (TSS) and total dissolved
solids (TDS), but in both cases, pH adjustment had to be carried out
after treatment. The combination of lime and alum at the dose ratio
of 0.8:0.8 g/L was found to be optimum for the removal of inorganics.
The removal efficiency achieved at optimum
concentrations were 78.6, 62.0, 62.5 and 52.8% for color, alkalinity,
TSS and TDS, respectively. The major advantages of the lime-alum
combination were observed to be as follows: no requirement of pH
adjustment before and after treatment and good settleability of
sludge. Coagulation-precipitation followed by adsorption on PAC
resulted in 92.3% chemical oxygen demand (COD) removal and
100% phenol removal at equilibrium. Ammonia removal efficiency
was found to be 11.7% during coagulation-flocculation and 36.2%
during adsorption on PAC. Adsorption of organics on PAC in terms
of COD and phenol followed Freundlich isotherm with Kf = 0.55 &
18.47 mg/g and n = 1.01 & 1.45, respectively. This technology may
prove to be one of the fastest and most techno-economically feasible
methods for the treatment of tar-containing wastewater generated
from BGPs.
Abstract: Iron in groundwater is one of the problems that render the water unsuitable for drinking. The concentration above 0.3 mg/L is common in groundwater. The conventional method of removal is by precipitation under oxic condition. In this study, iron removal under anaerobic conditions was examined by batch experiment as a main purpose. The process involved by purging of groundwater samples with H2S to form iron sulfide. Removal up to 83% for 1 mg/L iron solution was achieved. The removal efficiency dropped to 82% and 75% for the higher initial iron concentrations 3.55 and 5.01 mg/L, respectively. The average residual sulfide concentration in water after the process was 25*g/L. The Eh level during the process was -272 mV. The removal process was found to follow the first order reaction with average rate constant of 4.52 x 10-3. The half-life for the concentrations to reduce from initial values was 157 minutes.
Abstract: Flash floods are considered natural disasters that can
cause casualties and demolishing of infra structures. The problem is
that flash floods, particularly in arid and semi arid zones, take place
in very short time. So, it is important to forecast flash floods earlier to
its events with a lead time up to 48 hours to give early warning alert
to avoid or minimize disasters. The flash flood took place over Wadi
Watier - Sinai Peninsula, in October 24th, 2008, has been simulated,
investigated and analyzed using the state of the art regional weather
model. The Weather Research and Forecast (WRF) model, which is a
reliable short term forecasting tool for precipitation events, has been
utilized over the study area. The model results have been calibrated
with the real data, for the same date and time, of the rainfall
measurements recorded at Sorah gauging station. The WRF model
forecasted total rainfall of 11.6 mm while the real measured one was
10.8 mm. The calibration shows significant consistency between
WRF model and real measurements results.
Abstract: Temperature, humidity and precipitation in an area,
are parameters proved influential in the climate of that area, and one
should recognize them so that he can determine the climate of that
area. Climate changes are of primary importance in climatology, and
in recent years, have been of great concern to researchers and even
politicians and organizations, for they can play an important role in
social, political and economic activities. Even though the real cause
of climate changes or their stability is not yet fully recognized, they
are a matter of concern to researchers and their importance for
countries has prompted them to investigate climate changes in
different levels, especially in regional, national and continental level.
This issue has less been investigated in our country. However, in
recent years, there have been some researches and conferences on
climate changes. This study is also in line with such researches and
tries to investigate and analyze the trends of climate changes
(temperature and precipitation) in Sefid-roud (the name of a river)
basin. Three parameters of mean annual precipitation, temperature,
and maximum and minimum temperatures in 36 synoptic and
climatology stations in a statistical period of 49 years (1956-2005) in
the stations of Sefid-roud basin were analyzed by Mann-Kendall test.
The results obtained by data analysis show that climate changes are
short term and have a trend. The analysis of mean temperature
revealed that changes have a significantly rising trend, besides the
precipitation has a significantly falling trend.
Abstract: Drought is natural and climate phenomenon and in fact server as a part of climate in an area and also it has significant environmental, social ,and economic consequences .drought differs from the other natural disasters from this viewpoint that it s a creeping phenomenon meaning that it progresses little and its difficult to determine the time of its onset and termination .most of the drought definitions are on based on precipitation shortage and consequently ,the shortage of water some of the activities related to the water such as agriculture In this research ,drought condition in Fars province was evacuated using SPI method within a 37 year – statistical –period(1974-2010)and maps related to the drought were prepared for each of the statistical period years. According to the results obtained from this research, the years 1974, 1976, 1975, 1982 with SPI (-1.03, 0.39, -1.05, -1.49) respectively, were the doughiest years and 1996,1997,2000 with SPI (2.49, 1.49, 1.46, 1.04) respectively, the most humid within the studying time series and the rest are in more normal conditions in the term of drought.
Abstract: Nowadays, precipitation prediction is required for proper planning and management of water resources. Prediction with neural network models has received increasing interest in various research and application domains. However, it is difficult to determine the best neural network architecture for prediction since it is not immediately obvious how many input or hidden nodes are used in the model. In this paper, neural network model is used as a forecasting tool. The major aim is to evaluate a suitable neural network model for monthly precipitation mapping of Myanmar. Using 3-layerd neural network models, 100 cases are tested by changing the number of input and hidden nodes from 1 to 10 nodes, respectively, and only one outputnode used. The optimum model with the suitable number of nodes is selected in accordance with the minimum forecast error. In measuring network performance using Root Mean Square Error (RMSE), experimental results significantly show that 3 inputs-10 hiddens-1 output architecture model gives the best prediction result for monthly precipitation in Myanmar.
Abstract: In this study, we sought to investigate the mercury
removal efficiency of manganese oxides from natural gas. The
fundamental studies on mercury removal with manganese oxides
sorbents were carried out in a laboratory scale fixed bed reactor at 30
°C with a mixture of methane (20%) and nitrogen gas laden with 4.8
ppb of elemental mercury. Manganese oxides with varying surface
area and crystalline phase were prepared by conventional precipitation
method in this study. The effects of surface area, crystallinity and
other metal oxides on mercury removal efficiency were investigated.
Effect of Ag impregnation on mercury removal efficiency was also
investigated. Ag supported on metal oxide such titania and zirconia as
reference materials were also used in this study for comparison. The
characteristics of mercury removal reaction with manganese oxide
was investigated using a temperature programmed desorption (TPD)
technique.
Manganese oxides showed very high Hg removal activity (about
73-93% Hg removal) for first time use. Surface area of the manganese
oxide samples decreased after heat-treatment and resulted in complete
loss of Hg removal ability for repeated use after Hg desorption in the
case of amorphous MnO2, and 75% loss of the initial Hg removal
activity for the crystalline MnO2. Mercury desorption efficiency of
crystalline MnO2 was very low (37%) for first time use and high (98%)
after second time use. Residual potassium content in MnO2 may have
some effect on the thermal stability of the adsorbed Hg species.
Desorption of Hg from manganese oxides occurs at much higher
temperatures (with a peak at 400 °C) than Ag/TiO2 or Ag/ZrO2.
Mercury may be captured on manganese oxides in the form of mercury
manganese oxide.
Abstract: Nano-MgO was successfully deposited on titania using deposition-precipitation method. The catalyst produced was characterised using FTIR, XRD, BET and XRF and its activity was tested on the transesterification reaction of soybean oil to biodiesel. The catalyst activity improved when the reaction temperature was increasedfrom 150 and 225 OC. It was also observed that increasing the reaction time above 1h had no significant benefit on conversion. The stability fixed MgO on TiO2 was investigated using XRF and ICP-OES. It was observed that MgO loss during the reaction was between 0.5-2.3 percent and that there was no correlation between the reaction temperature and the MgO loss.
Abstract: As the material used for fuselage structure must
possess low density, high strength to weight ratio, the selection of
appropriate materials for fuselage structure is one of the most
important tasks. Aluminum metal itself is soft and low in strength. It
can be made stronger by giving proper combination of suitable alloy
addition, mechanical treatment and thermal treatment. The usual
thermal treatment given to aluminum alloys is called age-hardening
or precipitation hardening. In this paper, the studies are carried out on
7075 aluminum alloy which is how to improve strength level for
fuselage structure. The marked effect of the strength on the ternary
alloy is clearly demonstrated at several ageing times and
temperatures. It is concluded that aluminum-zinc-magnesium alloy
can get the highest strength level in natural ageing.
Abstract: This work presents the first results from the long-term experiment, which is focused on the impact of intensive rainfall and long period of drought on microbial activities in soil. Fifteen lysimeters were prepared in the area of our interest. This area is a protection zone of underground source of drinking water. These lysimeters were filed with topsoil and subsoil collected in this area and divided into two groups. These groups differ in fertilization and amount of water received during the growing season. Amount of microbial biomass and leaching of mineral nitrogen and phosphates were chosen as main indicators of microbial activities in soil. Content of mineral nitrogen and phosphates was measured in soil solution, which was collected from each lysimeters. Amount of microbial biomass was determined in soil samples that were taken from the lysimeters before and after the long period of drought and intensive rainfall.
Abstract: Drought is one of the most damaging climate-related
hazards, it is generally considered as a prolonged absence of
precipitation. This normal and recurring climate phenomenon had
plagued civilization throughout history because of the negative
impacts on economical, environmental and social sectors. Drought
characteristics are thus recognized as important factors in water
resources planning and management. The purpose of this study is to
detect the changes in drought frequency, persistence and severity
in the Ruhr river basin. The frequency of drought events was
calculated using the Standardized Precipitation Index (SPI). Used
data are daily precipitation records from seven meteorological
stations covering the period 1961-2007. The main benefit of the
application of this index is its versatility, only rainfall data is required
to deliver five major dimensions of a drought : duration, intensity,
severity, magnitude, and frequency. Furthermore, drought can be
calculated in different time steps. In this study SPI was calculated for
1, 3, 6, 9, 12, and 24 months. Several drought events were detected
in the covered period, these events contain mild, moderate and severe
droughts. Also positive and negative trends in the SPI values were
observed.
Abstract: Iran has diverse climates and each have established distinct properties in their area. The extent and intensity of climatic factors effects on the lives of people living in various regions of Iran is so great that it cannot be simply ignored. In a large part of Iran known as the Central Plateau there is no precipitation for more than half of the year and dry weather and scarcity of fresh water pose an ever present problem for the people of these regions while in north of Iran upon the southern shores of the Caspian Sea the people face 80% humidity caused by the sea and 2 meters of annual precipitation. This article tries to review the past experiences of local architecture of Iran-s various regions so that they can be used to reshape and redirect the urban areas and structure of Iran-s current cities to provide environmental comfort by minimum use of fossil fuels.
Abstract: The purpose of this paper primarily intends to develop GIS interface for estimating sequences of stream-flows at ungauged stations based on known flows at gauged stations. The integrated GIS interface is composed of three major steps. The first, precipitation characteristics using statistical analysis is the procedure for making multiple linear regression equation to get the long term mean daily flow at ungauged stations. The independent variables in regression equation are mean daily flow and drainage area. Traditionally, mean flow data are generated by using Thissen polygon method. However, method for obtaining mean flow data can be selected by user such as Kriging, IDW (Inverse Distance Weighted), Spline methods as well as other traditional methods. At the second, flow duration curve (FDC) is computing at unguaged station by FDCs in gauged stations. Finally, the mean annual daily flow is computed by spatial interpolation algorithm. The third step is to obtain watershed/topographic characteristics. They are the most important factors which govern stream-flows. In summary, the simulated daily flow time series are compared with observed times series. The results using integrated GIS interface are closely similar and are well fitted each other. Also, the relationship between the topographic/watershed characteristics and stream flow time series is highly correlated.
Abstract: Based on the field investigation and long term remote
sensing data, the dynamics of the alpine wetland in the river basin and
their response to climate change were studied. Results showed the
alpine wetlands accounted for 3.73% of total basin in 2010. Lake and
river appeared an increasing trend in the past 30 years, with an
increase of 34.36 % and 24.57%. However, swamp exhibited a
tendency of decreasing with 233.74 km2. Annual average temperature,
maximum temperature, minimum temperature and precipitation in the
river basin all exhibited an increasing trend, whereas relative humidity
exhibited a decreasing trend. Ice and snow melting are main reasons of
lake and river area enhancement and swamp area descend. There
existed 91.78%-97.86% of reduced swamp converted into lakes on the
basis of remote sensing image interpretation. China-s government
policy of implementing development in the river basin is the major
driving force of artificial wetland growth.
Abstract: This study investigated possible ways to improve the
efficiency of the platinum precipitation process using ammonium
chloride by reducing the platinum content reporting to the effluent.
The ore treated consist of five platinum group metals namely,
ruthenium, rhodium, iridium, platinum, palladium and a precious
metal gold. Gold, ruthenium, rhodium and iridium were extracted
prior the platinum precipitation process. Temperature, reducing
agent, flow rate and potential difference were the variables controlled
to determine the operation conditions for optimum platinum
precipitation efficiency. Hydrogen peroxide was added as the
oxidizing agent at the temperature of 85-90oC and potential
difference of 700-850mV was the variable used to check the
oxidizing state of platinum. The platinum was further purified at
temperature between 60-65oC, potential difference above 700 mV,
ammonium chloride of 200 l, and at these conditions the platinum
content reporting to the effluent was reduced to less than 300ppm,
resulting in optimum platinum precipitation efficiency and purity of
99.9%.
Abstract: The gel-supported precipitation (GSP) process can be
used to make spherical particles (spherules) of nuclear fuel,
particularly for very high temperature reactors (VHTR) and even for
implementing the process called SPHEREPAC. In these different
cases, the main characteristics are the sphericity of the particles to be
manufactured and the control over their grain size. Nonetheless,
depending on the specifications defined for these spherical particles,
the GSP process has intrinsic limits, particularly when fabricating
very small particles. This paper describes the use of secondary
fragmentation (water, water/PVA and uranyl nitrate) on solid
surfaces under varying temperature and vibration conditions to assess
the relevance of using this new technique to manufacture very small
spherical particles by means of a modified GSP process. The
fragmentation mechanisms are monitored and analysed, before the
trends for its subsequent optimised application are described.
Abstract: Permeability reduction induced by asphaltene
precipitation during gas injection is one of the serious problems in
the oil industry. This problem can lead to formation damage and
decrease the oil production rate. In this work, Malaysian light oil
sample has been used to investigate the effect CO2 injection and
Water Alternating Gas (WAG) injection on permeability reduction.
In this work, dynamic core flooding experiments were conducted to
study the effect of CO2 and WAG injection on the amount of
asphaltene precipitated. Core properties after displacement were
inspected for any permeability reduction to study the effect of
asphaltene precipitation on rock properties.
The results showed that WAG injection gave less asphaltene
precipitation and formation damage compared to CO2 injection. The
study suggested that WAG injection can be one of the important
factors of managing asphaltene precipitation.