Abstract: Optimization of a microwave-assisted extraction of cherry laurel (Prunus laurocerasus) fruit using methanol was studied. The influence of process parameters (microwave power, plant material-to-solvent ratio and the extraction time) on the extraction efficiency were optimized by using response surface methodology. The predicted maximum yield of extractive substances (41.85 g/100 g fresh plant material) was obtained at microwave power of 600 W and plant material to solvent ratio of 0.2 g/cm3 after 26 minutes of extraction, while a mean value of 40.80±0.41 g/100 g fresh plant material was obtained from laboratory experiments. This proves applicability of the model in predicting optimal extraction conditions with minimal laborious and time consuming. The results indicated that all process parameters were effective on the extraction efficiency, while the most important factor was extraction time. In order to rationalize production the optimal economical condition which gave a large total extract yield with minimal energy and solvent consumption was found.
Abstract: Collaborative planning, forecasting and
replenishment (CPFR) coordinates the various supply chain
management activities including production and purchase planning,
demand forecasting and inventory replenishment between supply
chain trading partners. This study proposes a systematic way of
analyzing CPFR supporting factors using fuzzy cognitive map
(FCM) approach. FCMs have proven particularly useful for solving
problems in which a number of decision variables and
uncontrollable variables are causally interrelated. Hence the FCMs
of CPFR are created to show the relationships between the factors
that influence on effective implementation of CPFR in the supply
chain.
Abstract: Web-based systems have become increasingly
important due to the fact that the Internet and the World Wide Web
have become ubiquitous, surpassing all other technological
developments in our history. The Internet and especially companies
websites has rapidly evolved in their scope and extent of use, from
being a little more than fixed advertising material, i.e. a "web
presences", which had no particular influence for the company's
business, to being one of the most essential parts of the company's
core business.
Traditional software engineering approaches with process models
such as, for example, CMM and Waterfall models, do not work very
well since web system development differs from traditional
development. The development differs in several ways, for example,
there is a large gap between traditional software engineering designs
and concepts and the low-level implementation model, many of the
web based system development activities are business oriented (for
example web application are sales-oriented, web application and
intranets are content-oriented) and not engineering-oriented.
This paper aims to introduce Increment Iterative extreme
Programming (IIXP) methodology for developing web based
systems. In difference to the other existence methodologies, this
methodology is combination of different traditional and modern
software engineering and web engineering principles.
Abstract: Pure phase gallosilicate nitrite sodalite has been synthesized in a single step by low temperature (373 oK) hydrothermal technique. The product obtained was characterized using a combination of techniques including X-ray powder diffraction, IR, Raman spectroscopy, SEM, MAS NMR spectroscopy as well as thermogravimetry. Sodalite with an ideal composition was obtained after synthesis at 3730K and seven days duration using alkaline medium. The structural features of the Na8[GaSiO4]6(NO2)2 sodalite were investigated by IR, MAS NMR spectroscopy of 29Si and 23Na nuclei and by Reitveld refinement of X-ray powder diffraction data. The crystal structure of this sodalite has been refined in the space group P 4 3n; with a cell parameter 8.98386Å, V= 726.9 Å, (Rwp= 0.077 and Rp=0.0537) and Si-O-Ga angle is found to be 132.920 . MAS NMR study confirms complete ordering of Si and Ga in the gallosilicate framework. The surface area of single entity with stoichiometry Na8[GaSiO4]6(NO2)2 was found to be 8.083 x10-15 cm2/g.
Abstract: This paper presents a resonant-based read-out circuit for capacitive pressure sensors. The proposed read-out circuit consists of an LC oscillator and a counter. The circuit detects the capacitance changes of a capacitive pressure sensor by means of frequency shifts from its nominal operation frequency. The proposed circuit is designed in 0.18 m CMOS with an estimated power consumption of 43.1mW. Simulation results show that the circuit has a capacitive resolution of 8.06kHz/fF, which enables it for high resolution pressure detection.
Abstract: Adsorption of proteins onto a solid surface is believed to be the initial and controlling step in biofouling. A better knowledge of the fouling process can be obtained by controlling the formation of the first protein layer at a solid surface. A number of methods have been investigated to inhibit adsorption of proteins. In this study, the adsorption kinetics of
Abstract: This paper used a fuzzy kohonen neural network for medical image segmentation. Image segmentation plays a important role in the many of medical imaging applications by automating or facilitating the diagnostic. The paper analyses the tumor by extraction of the features of (area, entropy, means and standard deviation).These measurements gives a description for a tumor.
Abstract: Heavy metal transfer in soil profiles is a major
environmental concern because even slow transport through the soil
may eventually lead to deterioration of groundwater quality. The use
of sewage sludge and effluents from wastewater treatment plants for
irrigation of agricultural lands is on the rise particularly in peri-urban
area of developing countries. In this study soil samples under sludge
application and wastewater irrigation were studied and soil samples
were collected in the soil profiles from the surface to 100 cm in
depth. For this purpose, three plots were made in a treatment plant in
south of Tehran-Iran. First plot was irrigated just with effluent from
wastewater treatment plant, second plot with simulated heavy metals
concentration equal 50 years irrigation and in third plot sewage
sludge and effluent was used. Trace metals concentration (Cd, Cu)
were determined for soil samples. The results indicate movement of
metals was observed, but the most concentration of metals was found
in topsoil samples. The most of Cadmium concentration was
measured in the topsoil of plot 3, 4.5mg/kg and Maximum cadmium
movement was observed in 0-20 cm. The most concentration of
copper was 27.76mg/kg, and maximum percolation in 0-20 cm.
Metals (Cd, Cu) were measured in leached water. Preferential flow
and metal complexation with soluble organic apparently allow
leaching of heavy metals.
Abstract: In this study, static batch fermentation was used for bacterial cellulose production in date syrup solution (Bx. 10%) at 28°C using Gluconacetobacter. xylinus (PTCC 1734). The physicochemical properties of standard Sigma CMC and the produced carboxymethyl bacterial cellulose (CMBC) were studied using FT-IR spectroscopy, X-ray diffractometry (XRD) and Scanning Electron Microscopy (SEM). According to the FT-IR spectra the bands at 1664 and 1431 cm-1 indicate that carboxylic acid groups and carboxylate groups exist on the surface. The SEM imaging of CMBC and CMC carried out in magnification of 1K. Comparing the SEM imaging obviously showed that the ribbon shape in CMC remained but the length of ribbons became shorter while that shape changed to flake shape for CMBC. Determination of the area under XRD patterns demonstrated that the crystallinity amount of CMC was more than that for CMBC (51.08% and 81.84% for CMBC and CMC, respectively).
Abstract: A statistical optimization was studied to design a media composition to produce optimum cellulolytic enzyme where palm oil mill effluent (POME) as a basal medium and filamentous fungus, Trichoderma reesei RUT-C30 were used in the liquid state bioconversion(LSB). 2% (w/v) total suspended solid, TSS, of the POME supplemented with 1% (w/v) cellulose, 0.5%(w/v) peptone and 0.02% (v/v) Tween 80 was estimated to produce the optimum CMCase activity of 18.53 U/ml through the statistical analysis followed by the faced centered central composite design(FCCCD). The probability values of cellulose (
Abstract: Using ab initio theoretical calculations, we present
analysis of fragmentation process. The analysis is performed in two
steps. The first step is calculation of fragmentation energies by ab
initio calculations. The second step is application of the energies to
kinetic description of process. The energies of fragments are
presented in this paper. The kinetics of fragmentation process can be
described by numerical models. The method for kinetic analysis is
described in this paper. The result - composition of fragmentation
products - will be calculated in future. The results from model can be
compared to the concentrations of fragments from mass spectrum.
Abstract: A high-linearity and high-speed current-mode sampleand-
hold circuit is designed and simulated using a 0.25μm CMOS
technology. This circuit design is based on low voltage and it utilizes
a fully differential circuit. Due to the use of only two switches the
switch related noise has been reduced. Signal - dependent -error is
completely eliminated by a new zero voltage switching technique.
The circuit has a linearity error equal to ±0.05μa, i.e. 12-bit
accuracy with a ±160 μa differential output - input signal frequency
of 5MHZ, and sampling frequency of 100 MHZ. Third
harmonic is equal to –78dB.
Abstract: A new design approach for three-stage operational
amplifiers (op-amps) is proposed. It allows to actually implement a
symmetrical push-pull class-AB amplifier output stage for wellestablished
three-stage amplifiers using a feedforward
transconductance stage. Compared with the conventional design
practice, the proposed approach leads to a significant
improvement of the symmetry between the positive and the
negative op-amp step response, resulting in similar values of the
positive/negative settling time. The new approach proves to be very
useful in order to fully exploit the potentiality allowed by the op-amp
in terms of speed performances. Design examples in a commercial
0.35-μm CMOS prove the effectiveness of theproposed strategy.
Abstract: Economic models are complex dynamic systems with a lot of uncertainties and fuzzy data. Conventional modeling approaches using well known methods and techniques cannot provide realistic and satisfactory answers to today-s challenging economic problems. Qualitative modeling using fuzzy logic and intelligent system theories can be used to model macroeconomic models. Fuzzy Cognitive maps (FCM) is a new method been used to model the dynamic behavior of complex systems. For the first time FCMs and the Mamdani Model of Intelligent control is used to model macroeconomic models. This new model is referred as the Mamdani Rule-Based Fuzzy Cognitive Map (MBFCM) and provides the academic and research community with a new promising integrated advanced computational model. A new economic model is developed for a qualitative approach to Macroeconomic modeling. Fuzzy Controllers for such models are designed. Simulation results for an economic scenario are provided and extensively discussed
Abstract: In this paper, some experiments of liquid dispersion flow driven by explosion in vertical plane were carried out using a liquid explosive dispersion device with film cylindrical constraints. The separated time series describing the breakup shape and dispersion process of liquid were recorded with high speed CMOS camera. The experimental results were analyzed and some essential characteristics of liquid dispersing flow are presented.
Abstract: Cattle manure and mineral fertilizers are two source
of Nitrogen, which can affect the growth and quantity of potato. In
this research the effects of the use of cattle manure (5, 10, 15 and 20
ton ha-1), Nitrogen fertilizer (50, 100 and 150 kg N ha-1) and their
interaction on potato growth were evaluated during field
experiments in 2008 with the help of Randomized Complete Block
(RCB) with the factorial arrangement of three experimental
replications in Iran. At the 75 th day after emergence, dry weight of
Shoots, leaf area index (LAI) and plant height were recorded. Results
showed that, dry weight of Shoots, LAI and plant height increased
linearly and very significantly in response to the application of
manure and Nitrogen fertilizer. While the interaction between
manure and Nitrogen fertilizer just on the LAI and plant height was
significant, somehow the maximum amount of plant height( 73 cm)
was obtained by using 150 kg Nitrogen + 15 tons of manure per
hectare, and maximum LAI ( 5.36) was obtained by using 150 kg
Nitrogen + 20 tons of manure per hectare. Also in this experiment
maximum tuber yield (36.8 tons ha-1) was obtained by the utilization
of 150 kg Nitrogen per hectare + 20 tons manure.
Abstract: Liners are made to protect the groundwater table from
the infiltration of leachate which normally carries different kinds of
toxic materials from landfills. Although these liners are engineered to
last for long period of time; unfortunately these liners fail; therefore,
toxic materials pass to groundwater. This paper focuses on the
changes of the hydraulic conductivity of a sand-bentonite liner due to
the infiltration of biofuel and ethanol fuel. Series of laboratory tests
were conducted in 20-cm-high PVC columns. Several compositions
of sand-bentonite liners were tested: 95% sand: 5% bentonite; 90%
sand: 10% bentonite; and 100% sand (passed mesh #40). The
columns were subjected to extreme pressures of 40 kPa, and 100 kPa
to evaluate the transport of alternative fuels (biofuel and ethanol
fuel). For comparative studies, similar tests were carried out using
water. Results showed that hydraulic conductivity increased due to
the infiltration of alternative fuels through the liners. Accordingly,
the increase in the hydraulic conductivity showed significant
dependency on the type of liner mixture and the characteristics of the
liquid. The hydraulic conductivity of a liner (subjected to biofuel
infiltration) consisting of 5% bentonite: 95% sand under pressure of
40 kPa and 100 kPa had increased by one fold. In addition, the
hydraulic conductivity of a liner consisting of 10% bentonite: 90%
sand under pressure of 40 kPa and 100 kPa and infiltrated by biofuel
had increased by three folds. On the other hand, the results obtained
by water infiltration under 40 kPa showed lower hydraulic
conductivities of 1.50×10-5 and 1.37×10-9 cm/s for 5% bentonite:
95% sand, and 10% bentonite: 90% sand, respectively. Similarly,
under 100 kPa, the hydraulic conductivities were 2.30×10-5 and
1.90×10-9 cm/s for 5% bentonite: 95% sand, and 10% bentonite: 90%
sand, respectively.
Abstract: This paper presents the design and layout of a two stage, high speed operational amplifiers using standard 0.35um CMOS technology. The design procedure involves designing the bias circuit, the differential input pair, and the gain stage using CAD tools. Both schematic and layout of the operational amplifier along with the comparison in the results of the two has been presented. The operational amplifier designed, has a gain of 93.51db at low frequencies. It has a gain bandwidth product of 55.07MHz, phase margin of 51.9º and a slew rate of 22v/us for a load of capacitor of 10pF.
Abstract: In this work we present a solution for DAGC (Digital
Automatic Gain Control) in WLAN receivers compatible to IEEE 802.11a/g standard. Those standards define communication in 5/2.4
GHz band using Orthogonal Frequency Division Multiplexing OFDM modulation scheme. WLAN Transceiver that we have used
enables gain control over Low Noise Amplifier (LNA) and a
Variable Gain Amplifier (VGA). The control over those signals is
performed in our digital baseband processor using dedicated hardware block DAGC. DAGC in this process is used to automatically control the VGA and LNA in order to achieve better
signal-to-noise ratio, decrease FER (Frame Error Rate) and hold the
average power of the baseband signal close to the desired set point.
DAGC function in baseband processor is done in few steps: measuring power levels of baseband samples of an RF signal,accumulating the differences between the measured power level and
actual gain setting, adjusting a gain factor of the accumulation, and
applying the adjusted gain factor the baseband values. Based on the measurement results of RSSI signal dependence to input power we have concluded that this digital AGC can be implemented applying
the simple linearization of the RSSI. This solution is very simple but also effective and reduces complexity and power consumption of the
DAGC. This DAGC is implemented and tested both in FPGA and in ASIC as a part of our WLAN baseband processor. Finally, we have integrated this circuit in a compact WLAN PCMCIA board based on MAC and baseband ASIC chips designed from us.
Abstract: To help overcome limits to the density of conventional SRAMs and leakage current of SRAM cell in nanoscaled CMOS technology, we have developed a four-transistor SRAM cell. The newly developed CMOS four-transistor SRAM cell uses one word-line and one bit-line during read/write operation. This cell retains its data with leakage current and positive feedback without refresh cycle. The new cell size is 19% smaller than a conventional six-transistor cell using same design rules. Also the leakage current of new cell is 60% smaller than a conventional sixtransistor SRAM cell. Simulation result in 65nm CMOS technology shows new cell has correct operation during read/write operation and idle mode.