Abstract: Addis Ababa is a seat of African Union (AU), United
Nations Economic Commission for Africa (UN-ECA) and hundreds of
embassies and consular representatives. Addis Ababa is one of the
highest capitals in the world with an average 2400 meters above sea
level. It is dichotomous city with a blend of modern high-rise and
deteriorating slum quarters. Water supply and sanitation, waste
management and housing are continuing to be serious problems.
Forest wood based domestic energy use as well as uncontrolled
emissions from mobile and fixed sources has endangered the state of
the urban environment. Analysis based on satellite imagery has
revealed the deteriorating urban environment within the last three
decades. The recently restructured city administration has brought
improvements in the condition of the urban environment. However,
the overwhelming size of the challenges faced by the city dwarfed
their fairly good results.
Abstract: This work concerns the measurements of a Bulk
Acoustic Waves (BAW) emission filter S parameters and compare
with prototypes simulated types. Thanks to HP-ADS, a co-simulation
of filters- characteristics in a digital radio-communication chain is
performed. Four cases of modulation schemes are studied in order to
illustrate the impact of the spectral occupation of the modulated
signal. Results of simulations and co-simulation are given in terms of
Error Vector Measurements to be useful for a general sensibility
analysis of 4th/3rd Generation (G.) emitters (wideband QAM and
OFDM signals)
Abstract: Low-carbon economy means the energy conservation and emission reduction. How to measure and evaluate the regional low-carbon economy is an important problem which should be solved immediately. This paper proposed the eco-efficiency ratio based on the ecological efficiency to evaluate the current situation of the low-carbon economy in Jiangsu province and to analyze the efficiency of the low-carbon economy in Jiangsu and other provinces, compared both advantages and disadvantages. And then this paper put forward some advices for the government to formulate the correct development policy of low-carbon economy, to improve the technology innovation capacity and the efficiency of resource allocation.
Abstract: The concerns about clean environment and high oil
prices driving forces for the research on alternative fuels. The
research efforts directed towards improving the performance of C.I
engines using vegetable oil as fuel. The paper deals results of
performance of a four stroke, single cylinder C.I. engine by preheated
neat Karanja oil is done from 30
o
C to 100
o
C. The performance of the
engine was studied for a speed range between 1500 to 4000 rpm, with
the engine operated under full load conditions. The performance
parameters considered for comparing are brake specific fuel
consumption, thermal efficiency, brake power, Nox emission of the
engine. The engine offers lower thermal efficiency when it is
powered by preheated neat Karanja oil at higher speed. The power
developed and Nox emission increase with the increase in the fuel
inlet temperature and the specific fuel consumption is higher than
diesel fuel operation at all elevated fuel inlet temperature.
Abstract: This paper reports a new application of material accounting techniques to characterise and quantify material stocks and flows at the “neighbourhood" scale. The study area is the main campus of the University of New South Wales in Sydney, Australia. The system boundary is defined by the urban structural unit (USU), a typological construct devised to facilitate assessment of the metabolism of urban systems. A streamlined material flow analysis (MFA) was applied to quantify the stocks and flows of key construction materials within the campus USU over time, drawing on empirical data from a major campus development project. The results are reviewed to assess the efficacy of the method in supporting urban environmental evaluation and design practice, for example to facilitate estimation of significant impacts such as greenhouse gas emissions. It is concluded that linking a service (in this case, teaching students) enabled by a given product (university buildings) to the amount of materials used in creating that product offers a potential way to reduce the environmental impact of that service, through more efficient use of materials.
Abstract: The InAlGaN alloy has only recently began receiving
serious attention into its growth and application. High quality InGaN
films have led to the development of light emitting diodes (LEDs) and
blue laser diodes (LDs). The quaternary InAlGaN however, represents
a more versatile material since the bandgap and lattice constant can be
independently varied. We report an ultraviolet (UV) quaternary
InAlGaN multi-quantum wells (MQWs) LD study by using the
simulation program of Integrated System Engineering (ISE TCAD).
Advanced physical models of semiconductor properties were used in
order to obtain an optimized structure. The device performance which
is affected by piezoelectric and thermal effects was studied via
drift-diffusion model for carrier transport, optical gain and loss. The
optical performance of the UV LD with different numbers of quantum
wells was numerically investigated. The main peak of the emission
wavelength for double quantum wells (DQWs) was shifted from 358
to 355.8 nm when the forward current was increased. Preliminary
simulated results indicated that better output performance and lower
threshold current could be obtained when the quantum number is four,
with output power of 130 mW and threshold current of 140 mA.
Abstract: This paper contributes to the debate on the proximate
causes of climate change. Also, it discusses the impact of the global
temperature increases since the beginning of the twentieth century
and the effectiveness of climate change models in isolating the
primary cause (anthropogenic influences or natural variability in
temperature) of the observed temperature increases that occurred
within this period. The paper argues that if climate scientist and
policymakers ignore the anthropogenic influence (greenhouse gases)
on global warming on the pretense of lack of agreement among
various climate models and their inability to account for all the
necessary factors of global warming at all levels the current efforts of
greenhouse emissions control and global warming as a whole could
be exacerbated.
Abstract: New regulations and standards for noise emission increasingly compel the automotive firms to make some improvements about decreasing the engine noise. Nowadays, the perforated reactive mufflers which have an effective damping capability are specifically used for this purpose. New designs should be analyzed with respect to both acoustics and back pressure. In this study, a reactive perforated muffler is investigated numerically and experimentally. For an acoustical analysis, the transmission loss which is independent of sound source of the present cross flow, the perforated muffler was analyzed by COMSOL. To be able to validate the numerical results, transmission loss was measured experimentally. Back pressure was obtained based on the flow field analysis and was also compared with experimental results. Numerical results have an approximate error of 20% compared to experimental results.
Abstract: The significance of emissions from the road transport
sector (such as air pollution, noise, etc) has grown considerably in
recent years. In Australia, 14.3% of national greenhouse gas
emissions in 2000 were the transport sector-s share which 12.9% of
net national emissions were related to a road transport alone.
Considering the growing attention to the green house gas(GHG)
emissions, this paper attempts to provide air pollution modeling
aspects of environmental consequences of the road transport by using
one of the best computer based tools including the Geographic
Information System (GIS). In other word, in this study, GIS and its
applications is explained, models which are used to model air
pollution and GHG emissions from vehicles are described and GIS is
applied in real case study that attempts to forecast GHG emission
from people who travel to work by car in 2031 in Melbourne for
analysing results as thematic maps.
Abstract: In the present study, the rate of NOx emission in a
combustion chamber working in conventional combustion and High
Temperature Air Combustion (HiTAC) system are examined using
CFD modeling. The effect of peak temperature, combustion air
temperature and oxygen concentration on NOx emission rate was
undertaken. Results show that in a fixed oxygen concentration,
increasing the preheated air temperature will increase the peak
temperature and NOx emission rate. In addition, it was observed that
the reduction of the oxygen concentration in the fixed preheated air
temperature decreases the peak temperature and NOx emission rate.
On the other hand, the results show that increase of preheated air
temperature at various oxygen concentrations increases the NOx
emission rate. However, the rate of increase in HiTAC conditions is
quite lower than the conventional combustion. The modeling results
show that the NOx emission rate in HiTAC combustion is 133% less
than that of the conventional combustion.
Abstract: This paper focuses on assessment of air pollution in Umm-Alhyman, Kuwait, which is located south to oil refineries, power station, oil field, and highways. The measurements were made over a period of four days in March and July in 2001, 2004, and 2008. The measured pollutants included methanated and nonmethanated hydrocarbons (MHC, NMHC), CO, CO2, SO2, NOX, O3, and PM10. Also, meteorological parameters were measured, which includes temperature, wind speed and direction, and solar radiation. Over the study period, data analysis showed increase in measured SO2, NOX and CO by factors of 1.2, 5.5 and 2, respectively. This is explained in terms of increase in industrial activities, motor vehicle density, and power generation. Predictions of the measured data were made by the ISC-AERMOD software package and by using the ISCST3 model option. Finally, comparison was made between measured data against international standards.
Abstract: In this paper, a Dynamic Economic Dispatch (DED) model is developed for the system consisting of both thermal generators and wind turbines. The inclusion of a significant amount of wind energy into power systems has resulted in additional constraints on DED to accommodate the intermittent nature of the output. The probability of stochastic wind power based on the Weibull probability density function is included in the model as a constraint; A Here-and-Now Approach. The Environmental Protection Agency-s hourly emission target, which gives the maximum emission during the day, is used as a constraint to reduce the atmospheric pollution. A 69-bus test system with non-smooth cost function is used to illustrate the effectiveness of the proposed model compared with static economic dispatch model with including the wind power.
Abstract: In this paper the problems associated with immunity
of embedded systems used in Motor-Drive systems are investigated
and appropriate solutions are presented. Integration of VSD motor
systems (Integral Motor) while partially reducing some of these
effects, adds to immunity problem of their embedded systems. Fail
safe operation of an Integral Motor in arduous industrial
environments is considered. In this paper an integral motor with a
unique design is proposed to overcome critical issues such as heat,
vibration and electromagnetic interference which are damaging to
sensitive electronics without requirement of any additional cooling
system. Advantages of the proposed Integral motor are compactness
of combo motor and drive system with no external cabling/wiring.
This motor provides a perfect shielding for least amount of radiated
emission. It has an inbuilt filter for EMC compliance and has been
designed to provide lower EMC noise for immunity of the internal
electronics as well as the other neighbouring systems.
Abstract: A comprehensive discussion of feasible strategies for sustainable energy supply is urgently needed to achieve a turnaround of the current energy situation. The necessary fundamentals required for the development of a long term energy vision are lacking to a great extent due to the absence of reasonable long term scenarios that fulfill the requirements of climate protection and sustainable energy use. The contribution of the study is based on a search for sustainable energy paths in the long run for Austria. The analysis makes use of secondary data predominantly. The measures developed to avoid CO2 emissions and other ecological risk factors vary to a great extent among all economic sectors. This is shown by the calculation of CO2 cost of abatement curves. In this study it is demonstrated that the most effective technical measures with the lowest CO2 abatement costs yield solutions to the current energy problems. Various scenarios are presented concerning the question how the technological and environmental options for a sustainable energy system for Austria could look like in the long run. It is shown how sustainable energy can be supplied even with today-s technological knowledge and options available. The scenarios developed include an evaluation of the economic costs and ecological impacts. The results are not only applicable to Austria but demonstrate feasible and cost efficient ways towards a sustainable future.
Abstract: This study applied the Gaussian trajectory
transfer-coefficient model (GTx) to simulate the particulate matter
concentrations and the source apportionments at Nanzih Air Quality
Monitoring Station in southern Taiwan from November 2007 to
February 2008. The correlation coefficient between the observed and
the calculated daily PM10 concentrations is 0.5 and the absolute bias of
the PM10 concentrations is 24%. The simulated PM10 concentrations
matched well with the observed data. Although the emission rate of
PM10 was dominated by area sources (58%), the results of source
apportionments indicated that the primary sources for PM10 at Nanzih
Station were point sources (42%), area sources (20%) and then upwind
boundary concentration (14%). The obvious difference of PM10 source
apportionment between episode and non-episode days was upwind
boundary concentrations which contributed to 20% and 11% PM10
sources, respectively. The gas-particle conversion of secondary
aerosol and long range transport played crucial roles on the PM10
contribution to a receptor.
Abstract: Combustion, emission and performance
characterization of a single cylinder diesel engine using methanol
diesel blends was carried out. The blends were 5% (v/v) methanol in
diesel (MD05) and 10% (v/v) methanol in diesel (MD10). The
problem of solubility of methanol and diesel was addressed by an
agitator placed inside the fuel tank to prevent phase separation. The
results indicated that total combustion duration was reduced by15.8%
for MD05 and 31.27% for MD10compared to the baseline data.
Ignition delay was increased with increasing methanol volume
fraction in the test fuel. Total cyclic heat release was reduced by
1.5% for MD05 and 6.7% for MD10 as compared to diesel baseline.
Emissions of carbon monoxide, hydrocarbons along with smoke were
reduced and that of nitrogen oxides were increased with rising
methanol contents in the test fuel. Full load brake thermal efficiency
was marginally reduced with increased methanol composition in the
blend.
Abstract: Municipal solid waste (MSW) comprises of a wide
range of heterogeneous materials generated by individual, household
or organization and may include food waste, garden wastes, papers,
textiles, rubbers, plastics, glass, ceramics, metals, wood wastes,
construction wastes but it is not limited to the above mentioned
fractions. The most common Municipal Solid Waste pretreatment
method in use is thermal pretreatment (incineration) and Mechanical
Biological pretreatment. This paper presents an overview of these
two pretreatment methods describing their benefits and laboratory
scale reactors that simulate landfill conditions were constructed in
order to compare emissions in terms of biogas production and
leachate contamination between untreated Municipal Solid Waste and
Mechanical Biological Pretreated waste. The findings of this study
showed that Mechanical Biological pretreatment of waste reduces the
emission level of waste and the benefit over the landfilling of
untreated waste is significant.
Abstract: This research studied recycled waste by the Recyclable Material Bank Project of 4 universities in the central region of Thailand for the evaluation of reducing greenhouse gas emissions compared with landfilling activity during July 2012 to June 2013. The results showed that the projects collected total amount of recyclable wastes of about 911,984.80 kilograms. Office paper had the largest amount among these recycled wastes (50.68% of total recycled waste). Groups of recycled waste can be prioritized from high to low according to their amount as paper, plastic, glass, mixed recyclables, and metal, respectively. The project reduced greenhouse gas emissions equivalent to about 2814.969 metric tons of carbon dioxide. The most significant recycled waste that affects the reduction of greenhouse gas emissions is office paper which is 70.16% of total reduced greenhouse gasses emission. According to amount of reduced greenhouse gasses emission, groups of recycled waste can be prioritized from high to low significances as paper, plastic, metals, mixed recyclables, and glass, respectively.
Abstract: This paper presents an experimental investigation using Acoustic Emission (AE) technology to monitor sand transportation in multiphase flow. The investigations were undertaken on three-phase (air-water-sand) flow in a horizontal pipe where the superficial gas velocity (VSG) had a range of between 0.2msˉ¹ to 2.0msˉ¹ and superficial liquid velocity (VSL) had a range of between 0.2msˉ¹ to 1.0msˉ¹. The experimental findings clearly show a correlation exists between AE energy levels, sand concentration, superficial gas velocity (VSG), and superficial liquid velocity (VSL).
Abstract: One promising way to achieve low temperature
combustion regime is the use of a large amount of cooled EGR. In
this paper, the effect of injection timing on low temperature
combustion process and emissions were investigated via three
dimensional computational fluid dynamics (CFD) procedures in a DI
diesel engine using high EGR rates. The results show when
increasing EGR from low levels to levels corresponding to reduced
temperature combustion, soot emission after first increasing, is
decreased beyond 40% EGR and get the lowest value at 58% EGR
rate. Soot and NOx emissions are simultaneously decreased at
advanced injection timing before 20.5 ºCA BTDC in conjunction
with 58% cooled EGR rate in compared to baseline case.