Abstract: A simple analytical model has been developed to
optimize biasing conditions for obtaining maximum linearity among
lattice-matched, pseudomorphic and metamorphic HEMT types as
well as enhancement and depletion HEMT modes. A nonlinear
current-voltage model has been simulated based on extracted data to
study and select the most appropriate type and mode of HEMT in
terms of a given gate-source biasing voltage within the device so as
to employ the circuit for the highest possible output current or
voltage linear swing. Simulation results can be used as a basis for the
selection of optimum gate-source biasing voltage for a given type
and mode of HEMT with regard to a circuit design. The
consequences can also be a criterion for choosing the optimum type
or mode of HEMT for a predetermined biasing condition.
Abstract: This paper presents a method of reducing the feedback
delay time of DWA(Data Weighted Averaging) used in sigma-delta
modulators. The delay time reduction results from the elimination of
the latch at the quantizer output and also from the falling edge
operation. The designed sigma-delta modulator improves the timing
margin about 16%. The sub-circuits of sigma-delta modulator such as
SC(Switched Capacitor) integrator, 9-level quantizer, comparator, and
DWA are designed with the non-ideal characteristics taken into
account. The sigma-delta modulator has a maximum SNR (Signal to
Noise Ratio) of 84 dB or 13 bit resolution.
Abstract: Accurate demand forecasting is one of the most key
issues in inventory management of spare parts. The problem of
modeling future consumption becomes especially difficult for lumpy
patterns, which characterized by intervals in which there is no
demand and, periods with actual demand occurrences with large
variation in demand levels. However, many of the forecasting
methods may perform poorly when demand for an item is lumpy.
In this study based on the characteristic of lumpy demand patterns
of spare parts a hybrid forecasting approach has been developed,
which use a multi-layered perceptron neural network and a
traditional recursive method for forecasting future demands. In the
described approach the multi-layered perceptron are adapted to
forecast occurrences of non-zero demands, and then a conventional
recursive method is used to estimate the quantity of non-zero
demands. In order to evaluate the performance of the proposed
approach, their forecasts were compared to those obtained by using
Syntetos & Boylan approximation, recently employed multi-layered
perceptron neural network, generalized regression neural network
and elman recurrent neural network in this area. The models were
applied to forecast future demand of spare parts of Arak
Petrochemical Company in Iran, using 30 types of real data sets. The
results indicate that the forecasts obtained by using our proposed
mode are superior to those obtained by using other methods.
Abstract: As various mobile sensing technologies, remote
control and ubiquitous infrastructure are developing and expectations
on quality of life are increasing, a lot of researches and developments
on home network technologies and services are actively on going,
Until now, we have focused on how to provide users with high-level
home network services, while not many researches on home network
security for guaranteeing safety are progressing. So, in this paper, we
propose an access control model specific to home network that
provides various kinds of users with home network services up one-s
characteristics and features, and protects home network systems from
illegal/unnecessary accesses or intrusions.
Abstract: Globin superfamily proteins including myoglobin and
hemoglobin, have welcome new members recently, namely,
cytoglobin, neuroglobin and globin X, though their physiological
functions are still to be addressed. Fish are the excellent models for the
study of these globins, but their characteristics have not yet been
discussed to date. In the present study, attempts have been made to
characterize their structural uniqueness by making use of proteomics
approach. This is the first comparative study on the characterization of
globin superfamily proteins from fish.
Abstract: New advancement of technology and never satisfying demands of the civilization are putting huge pressure on the natural fuel resources and these resources are at a constant threat to its sustainability. To get the best out of the automobile, the optimum balance between performance and fuel economy is important. In the present state of art, either of the above two aspects are taken into mind while designing and development process which puts the other in the loss as increase in fuel economy leads to decrement in performance and vice-versa. In-depth observation of the vehicle dynamics apparently shows that large amount of energy is lost during braking and likewise large amount of fuel is consumed to reclaim the initial state, this leads to lower fuel efficiency to gain the same performance. Current use of Kinetic Energy Recovery System is only limited to sports vehicles only because of the higher cost of this system. They are also temporary in nature as power can be squeezed only during a small time duration and use of superior parts leads to high cost, which results on concentration on performance only and neglecting the fuel economy. In this paper Kinetic Energy Recovery System for storing the power and then using the same while accelerating has been discussed. The major storing element in this system is a Flat Spiral Spring that will store energy by compression and torsion.
The use of spring ensure the permanent storage of energy until used by the driver unlike present mechanical regeneration system in which the energy stored decreases with time and is eventually lost. A combination of internal gears and spur gears will be used in order to make the energy release uniform which will lead to safe usage. The system can be used to improve the fuel efficiency by assisting in overcoming the vehicle’s inertia after braking or to provide instant acceleration whenever required by the driver. The performance characteristics of the system including response time, mechanical efficiency and overall increase in efficiency are demonstrated. This technology makes the KERS (Kinetic Energy Recovery System) more flexible and economical allowing specific application while at the same time increasing the time frame and ease of usage.
Abstract: Curing of paints by exposure to UV radiations is
emerging as one of the best film forming technique as an alternative
to traditional solvent borne oxidative and thermal curing coatings.
The composition and chemistry of UV curable coatings and role of
multifunctional and monofunctional monomers, oligomers, and
photoinitiators have been discussed. The limitations imposed by
thermodynamic equilibrium and tendency for acrylic double bond
polymerizations during synthesis of multifunctional acrylates have
been presented. Aim of present investigation was thus to explore the
reaction variables associated with synthesis of multifunctional
acrylates. Zirconium oxychloride was evaluated as catalyst against
regular acid functional catalyst. The catalyzed synthesis of glyceryl
acrylate and neopentyl glycol acrylate was conducted by variation of
following reaction parameters: two different reactant molar ratios-
1:4 and 1:6; catalyst usage in % by moles on polyol- 2.5, 5.0 and 7.5
and two different reaction temperatures- 45 and 75 0C. The reaction
was monitored by determination of acid value and hydroxy value at
regular intervals, besides TLC, HPLC, and FTIR analysis of
intermediates and products. On the basis of determination of reaction
progress over 1-60 hrs, the esterification reaction was observed to
follow 2nd order kinetics with rate constant varying from 1*10-4 to
7*10-4. The thermal and catalytic components of second order rate
constant and energy of activation were also determined. Uses of
these kinetic and thermodynamic parameters in design of reactor for
manufacture of multifunctional acrylate ester have been presented.
The synthesized multifunctional acrylates were used to formulate and
apply UV curable clear coat followed by determination of curing
characteristics and mechanical properties of cured film. The overall
curing rates less than 05 min. were easily attained indicating
economical viability of radiation curable system due to faster
production schedules
Abstract: SVM ( Support Vector Machine ) is a new method in the artificial neural network ( ANN ). In the steel making, how to use computer to predict the end point of BOF accuracy is a great problem. A lot of method and theory have been claimed, but most of the results is not satisfied. Now the hot topic in the BOF end point predicting is to use optical way the predict the end point in the BOF. And we found that there exist some regular in the characteristic curve of the flame from the mouse of pudding. And we can use SVM to predict end point of the BOF, just single spectrum intensity should be required as the input parameter. Moreover, its compatibility for the input space is better than the BP network.
Abstract: In this work we report on preliminary analysis of a novel optoelectronic gas sensor based on an optical fiber integrated with a tetrakis(4-sulfonatophenyl)porphyrin (TPPS) thin film. The sensitive materials are selectively deposited on the core region of a fiber tip by UV light induced deposition technique. A simple and cheap process which can be easily extended to different porphyrin derivatives. When the TPPS film on the fiber tip is exposed to acid and/or base vapors, dramatic changes occur in the aggregation structure of the dye molecules in the film, from J- to H-type, resulting in a profound modification of their corresponding reflectance spectra. From the achieved experimental results it is evident that the presence of intense and narrow band peaks in the reflected spectra could be monitored to detect hazardous vapors.
Abstract: A numerical solution of the initial boundary value
problem of the suspended string vibrating equation with the
particular nonlinear damping term based on the finite difference
scheme is presented in this paper. The investigation of how the
second and third power terms of the nonlinear term affect the
vibration characteristic. We compare the vibration amplitude as a
result of the third power nonlinear damping with the second power
obtained from previous report provided that the same initial shape
and initial velocities are assumed. The comparison results show that
the vibration amplitude is inversely proportional to the coefficient of
the damping term for the third power nonlinear damping case, while
the vibration amplitude is proportional to the coefficient of the
damping term in the second power nonlinear damping case.
Abstract: The paper is included within the framework of a
complex research program, which was initiated from the hypothesis
arguing on the existence of a correlation between pineal indolic and
peptide hormones and the somatic development rhythm, including
thus the epithalamium-epiphysis complex involvement. At birds,
pineal gland contains a circadian oscillator, playing a main role in the
temporal organization of the cerebral functions. The secretion of
pineal indolic hormones is characterized by a high endogenous
rhythmic alternation, modulated by the light/darkness (L/D)
succession and by temperature as well. The research has been carried
out using 100 chicken broilers - “Ross" commercial hybrid,
randomly allocated in two experimental batches: Lc batch, reared
under a 12L/12D lighting schedule and Lexp batch, which was photic
pinealectomised through continuous exposition to light (150 lux, 24
hours, 56 days). Chemical and physical features of the meat issued
from breast fillet and thighs muscles have been studied, determining
the dry matter, proteins, fat, collagen, salt content and pH value, as
well. Besides the variations of meat chemical composition in relation
with lighting schedule, other parameters have been studied: live
weight dynamics, feed intake and somatic development degree. The
achieved results became significant since chickens have 7 days of
age, some variations of the studied parameters being registered,
revealing that the pineal gland physiologic activity, in relation with
the lighting schedule, could be interpreted through the monitoring of
the somatic development technological parameters, usually studied
within the chicken broilers rearing aviculture practice.
Abstract: A modified Saleh-Valenzuela channel model has been
adapted for Ultra Wideband (UWB) system. The suggested realistic
channel is assessed by its distribution of fading amplitude and time of
arrivals. Furthermore, the propagation characteristic has been distinct
into four channel models, namely CM 1 to 4. Each are differentiate in
terms of cluster arrival rates, rays arrival rate within each cluster and
its respective constant decay rates. This paper described the
multiband OFDM system performance simulates under these
multipath conditions. Simulation work described in this paper is
based on WiMedia ECMA-368 standard, which has been deployed
for practical implementation of low cost and low power UWB
devices.
Abstract: Due to the Rapid Urbanization in China, the influence of metropolises to surrounding areas grows by a tremendous speed in developed region. One of the most obvious influences is the expansion of the urban built-up areas which covers the land belongs to small towns. Around metropolitan fringe, the boundary between city and village becomes more and more obscure. So being the most sensitive area, the small towns on the fringe of metropolises have the special meaning on the research into the small towns- development. This paper chooses Sandun Town in Hangzhou of Zhejiang Province as an example, emphatically focus on aspects such as the central area proliferation, the industrial shift, the position effect, the subway effect and the commercial development, reviews a few problems of small towns in the future and the important problems in their planning by the analysis of the characteristics of the present conditions and the developing motive mechanism, so that guides small towns to develop properly by liking with these small towns and center metropolises.
Abstract: Porcine production in China represents approximately
the 50% of the worldwide pig production. Information about pig
husbandry characteristics in China and manure properties from sows
to fatteners in intensive pig farms are not broadly available for
scientific studies as it is a time consuming, expensive task and highly
inaccessible. This study provides a report about solid pig manures
(28% dry matter) in a commercial pig farm located in the peri-urban
area of Beijing as well as a general overview of the current pig
husbandry techniques including pig breeds, feeds, diseases, housing as
well as pig manure and wastewater disposal. The main results are
intended to serve as a literature source for young scientists in order to
understand the main composition of pig manures as well as to identify
the husbandry techniques applied in an intensive pig farm in Beijing.
Abstract: As a result of the high cost of housing, the increasing population is forced to live in substandard housing and unhealthy conditions giving rise to poor residential neighborhoods. The paper examines the causes and characteristics of poor residential neighborhood. The paper finds the problems that have influence poor neighborhoods to; poverty, growth of informal sector and housing shortage. The paper asserts that poor residential neighborhoods have adverse effects on the people.
The secondary data was obtained from books, journals and seminar papers while primary data relating to building and environmental quality from structured questionnaire administered on sample of 500 household heads, from sampling frame of 5000 housing units.
The study reveals that majority of the respondents are poor and employed in informal sector. The paper suggests urban renewal and slum upgrading programs as methods in dealing with the situation and an improvement in the socio-economic circumstances of the inhabitants.
Abstract: A SnO2/CdS/CdTe heterojunction was fabricated by
thermal evaporation technique. The fabricated cells were annealed at
573K for periods of 60, 120 and 180 minutes. The structural
properties of the solar cells have been studied by using X-ray
diffraction. Capacitance- voltage measurements were studied for the
as-prepared and annealed cells at a frequency of 102 Hz. The
capacitance- voltage measurements indicated that these cells are
abrupt. The capacitance decreases with increasing annealing time.
The zero bias depletion region width and the carrier concentration
increased with increasing annealing time. The carrier transport
mechanism for the CdS/CdTe heterojunction in dark is tunneling
recombination. The ideality factor is 1.56 and the reverse bias
saturation current is 9.6×10-10A. The energy band lineup for the n-
CdS/p-CdTe heterojunction was investigated using current - voltage
and capacitance - voltage characteristics.
Abstract: This study analyzes characteristics determining
member’s willingness to invest in cooperatives using ordered logit
model. The data were collected in a field survey among 122
cooperative members in north-central China. The descriptive analysis
of survey evidence suggests that cooperatives in China generally
having poor ability to deliver the processing services related to
product package, grading, and storage, performing worse in
profitability, inability of providing returns to capital and obtaining
agricultural loan. The regression results demonstrate that members’
farm size, their satisfaction with cooperative price preferential
services, attitudes toward cooperative operational scale and
development potential have statistically significant impact on
willingness to invest.
Abstract: A numerical study on the turbulent flow and heat
transfer characteristics in the rectangular channel with different types
of baffles is carried out. The inclined baffles have the width of 19.8
cm, the square diamond type hole having one side length of 2.55 cm,
and the inclination angle of 5o. Reynolds number is varied between
23,000 and 57,000. The SST turbulence model is applied in the
calculation. The validity of the numerical results is examined by the
experimental data. The numerical results of the flow field depict that
the flow patterns around the different baffle type are entirely different
and these significantly affect the local heat transfer characteristics.
The heat transfer and friction factor characteristics are significantly
affected by the perforation density of the baffle plate. It is found that
the heat transfer enhancement of baffle type II (3 hole baffle) has the
best values.
Abstract: This paper investigates vortex shedding processes
occurring at the end of a stack of parallel plates, due to an oscillating
flow induced by an acoustic standing wave within an acoustic
resonator. Here, Particle Image Velocimetry (PIV) is used to quantify
the vortex shedding processes within an acoustic cycle
phase-by-phase, in particular during the “ejection" of the fluid out of
the stack. Standard hot-wire anemometry measurement is also applied
to detect the velocity fluctuations near the end of the stack.
Combination of these two measurement techniques allowed a detailed
analysis of the vortex shedding phenomena. The results obtained show
that, as the Reynolds number varies (by varying the plate thickness
and drive ratio), different flow patterns of vortex shedding are
observed by the PIV measurement. On the other hand, the
time-dependent hot-wire measurements allow obtaining detailed
frequency spectra of the velocity signal, used for calculating
characteristic Strouhal numbers. The impact of the plate thickness and
the Reynolds number on the vortex shedding pattern has been
discussed. Furthermore, a detailed map of the relationship between the
Strouhal number and Reynolds number has been obtained and
discussed.
Abstract: Vortex-shedding phenomenon of the flow
around combined two bodies having various geometries and sizes has been investigated experimentally in the Reynolds
number range between 4.1x103 and 1.75x104. To see the effect
of the rotation of the bodies on the vortex shedding, the
combined bodies were rotated from 0° to 180°. The combined models have a cross section composing of a main circular cylinder and an attached circular or square cylinder. Results
have shown that Strouhal numbers for two cases were
changed considerably with the angle of incidence, while it was found to be largely independent of Reynolds number at 150. Characteristics of the vortex formation region and
location of flow attachments, reattachments, and separations
were observed by means of the flow visualizations.
Depending on the inclination angle the effects of flow
attachment, separation and reattachment on vortex-shedding phenomenon have been discussed.