Abstract: The renewable energy has been attracting attention as
a new alternative energy due to the problem of environmental
pollution and resource depletion. In particular, daylighting and PV
system are regarded as the solutions. In this paper, the hybrid
dimming control system supplied by solar cell and daylighting
system was designed. Daylighting system is main source and PV
system is spare source. PV system operates the LED lamp which
supports daylighting system because daylighting system is unstable
due to the variation of irradiance. In addition, PV system has a role
charging batteries. Battery charging has a benefit that PV system
operate LED lamp in the bad weather. However, LED lamp always
can`t turn on that-s why dimming control system was designed. In
particular, the solar charging robot was designed to check the
interior irradiance intensity. These systems and the application of
the solar charging robot are expected to contribute developing
alternative energy in the near future.
Abstract: One of the major problems in liberalized power
markets is loss allocation. In this paper, a different method for
allocating transmission losses to pool market participants is
proposed. The proposed method is fundamentally based on
decomposition of loss function and current projection concept. The
method has been implemented and tested on several networks and
one sample summarized in the paper. The results show that the
method is comprehensive and fair to allocating the energy losses of a
power market to its participants.
Abstract: In the last decade, energy based control theory has undergone a significant breakthrough in dealing with underactated mechanical systems with two successful and similar tools, controlled Lagrangians and controlled Hamiltanians (IDA-PBC). However, because of the complexity of these tools, successful case studies are lacking, in particular, MIMO cases. The seminal theoretical paper of controlled Lagrangians proposed by Bloch and his colleagues presented a benchmark example–a 4 d.o.f underactuated pendulum on a cart but a detailed and completed design is neglected. To compensate this ignorance, the note revisit their design idea by addressing explicit control functions for a similar device motivated by a vector thrust body hovering in the air. To the best of our knowledge, this system is the first MIMO, underactuated example that is stabilized by using energy based tools at the courtesy of the original design idea. Some observations are given based on computer simulation.
Abstract: Rolling element bearings are widely used in industry,
especially where high load capacity is required. The diagnosis of
their conditions is essential matter for downtime reduction and saving
cost of maintenance. Therefore, an intensive analysis of frequency
spectrum of their faults must be carried out in order to determine the
main reason of the fault. This paper focus on a beating phenomena
observed in the waveform (time domain) of a cylindrical rolling
element bearing. The beating frequencies were not related to any
sources nearby the machine nor any other malfunctions (unbalance,
misalignment ...etc). More investigation on the spike energy and the
frequency spectrum indicated a problem with races of the bearing.
Multi-harmonics of the fundamental defects frequencies were
observed. Two of them were close to each other in magnitude those
were the source of the beating phenomena.
Abstract: Wireless sensor networks is an emerging technology
that serves as environment monitors in many applications. Yet
these miniatures suffer from constrained resources in terms of
computation capabilities and energy resources. Limited energy
resource in these nodes demands an efficient consumption of that
resource either by developing the modules itself or by providing
an efficient communication protocols. This paper presents a
comprehensive summarization and a comparative study of the
available MAC protocols proposed for Wireless Sensor Networks
showing their capabilities and efficiency in terms of energy
consumption and delay guarantee.
Abstract: Because nodes are usually battery-powered, the energy
presents a very scarce resource in wireless sensor networks. For this
reason, the design of medium access control had to take energy
efficiency as one of its hottest concerns. Accordingly, in order to
improve the energy performance of MAC schemes in wireless sensor
networks, several ways can be followed. In fact, some researchers try
to limit idle listening while others focus on mitigating overhearing
(i.e. a node can hear a packet which is destined to another node)
or reducing the number of the used control packets. We, in this
paper, propose a new hybrid MAC protocol termed ELE-MAC
(i.e. Energy Latency Efficient MAC). The ELE-MAC major design
goals are energy and latency efficiencies. It adopts less control
packets than SMAC in order to preserve energy. We carried out ns-
2 simulations to evaluate the performance of the proposed protocol.
Thus, our simulation-s results prove the ELE-MAC energy efficiency.
Additionally, our solution performs statistically the same or better
latency characteristic compared to adaptive SMAC.
Abstract: This paper presents a novel method for prediction of
the mechanical behavior of proximal femur using the general
framework of the quantitative computed tomography (QCT)-based
finite element Analysis (FEA). A systematic imaging and modeling
procedure was developed for reliable correspondence between the
QCT-based FEA and the in-vitro mechanical testing. A speciallydesigned
holding frame was used to define and maintain a unique
geometrical reference system during the analysis and testing. The
QCT images were directly converted into voxel-based 3D finite
element models for linear and nonlinear analyses. The equivalent
plastic strain and the strain energy density measures were used to
identify the critical elements and predict the failure patterns. The
samples were destructively tested using a specially-designed gripping
fixture (with five degrees of freedom) mounted within a universal
mechanical testing machine. Very good agreements were found
between the experimental and the predicted failure patterns and the
associated load levels.
Abstract: Based on the thermodynamic theory, the dependence of
sublimation energy of metal on temperature and pressure is discussed,
and the results indicate that the sublimation energy decreases linearly
with the increase of temperature and pressure. Combined with this
result, the blow-off impulse of aluminum induced by pulsed X-ray is
simulated by smoothed particle hydrodynamics (SPH) method. The
numerical results show that, while the change of sublimation energy
with temperature and pressure is considered, the blow-off impulse of
aluminum is larger than the case that the sublimation energy is
assumed to be a constant.
Abstract: Cogeneration may be defined as a system which
contains electricity production and regain of the thermo value of
exhaust gases simultaneously. The examination is based on the data-s
of an active cogeneration plant. This study, it is aimed to determine
which component of the system should be revised first to raise the
efficiency and decrease the loss of exergy. For this purpose, second
law analysis of thermodynamics is applied to each component due to
consider the effects of environmental conditions and take the quality
of energy into consideration as well as the quantity of it. The exergy
balance equations are produced and exergy loss is calculated for each
component. 44,44 % loss of exergy in heat exchanger, 29,59 % in
combustion chamber, 18,68 % in steam boiler, 5,25 % in gas turbine
and 2,03 % in compressor is calculated.
Abstract: Combining energy efficiency with renewable energy
sources constitutes a key strategy for a sustainable future. The wind
power sector stands out as a fundamental element for the
achievement of the European renewable objectives and Portugal is no
exception to the increase of the wind energy for the electricity
generation. This work proposes an optimization model for the long
range electricity power planning in a system similar to the
Portuguese one, where the expected impacts of the increasing
installed wind power on the operating performance of thermal power
plants are taken into account. The main results indicate that the
increasing penetration of wind power in the electricity system will
have significant effects on the combined cycle gas power plants
operation and on the theoretically expected cost reduction and
environmental gains. This research demonstrated the need to address
the impact that energy sources with variable output may have, not
only on the short-term operational planning, but especially on the
medium to long range planning activities, in order to meet the
strategic objectives for the energy sector.
Abstract: Plasma plume will be produced and arrive at spacecraft when the electric thruster operates on orbit. It-s important to characterize the thruster plasma parameters because the plume has significant effects or hazards on spacecraft sub-systems and parts. Through the ground test data of the desired parameters, the major characteristics of the thruster plume will be achieved. Also it is very important for optimizing design of Ion thruster. Retarding Potential Analyzer (RPA) is an effective instrument for plasma ion energy per unit charge distribution measurement. Special RPA should be designed according to certain plume plasma parameters range and feature. In this paper, major principles usable for good RPA design are discussed carefully. Conform to these principles, a four-grid planar electrostatic energy analyzer RPA was designed to avoid false data, and details were discussed including construction, materials, aperture diameter and so on. At the same time, it was designed more suitable for credible and long-duration measurements in the laboratory. In the end, RPA measurement results in the laboratory were given and discussed.
Abstract: There has been a growing interest in the oxygenation
by plunging water jets in the last few years due to their inherent
advantages, like energy-efficient, low operation cost, etc. Though a
lot of work has been reported on the oxygen-transfer by single
plunging water jets but very few studies have been carried out using
multiple plunging jets. In this paper, volumetric oxygen-transfer
coefficient and oxygen-transfer efficiency has been studied
experimentally for multiple inclined plunging jets (having jet plunge
angle of 60 0 ) in a pool of water for different configurations, in
terms of varying number of jets and jet diameters. This research
suggests that the volumetric oxygen-transfer coefficient and oxygentransfer
efficiency of the multiple inclined plunging jets for air-water
system are significantly higher than those of a single vertical as well
as inclined plunging jet for same flow area and other similar
conditions. The study also reveals that the oxygen-transfer increase
with increase in number of multiple jets under similar conditions,
which will be most advantageous and energy-efficient in practical
situations when large volumes of wastewaters are to be treated. A
relationship between volumetric oxygen-transfer coefficient and jet
parameters is also proposed. The suggested relationship predicts the
volumetric oxygen-transfer coefficient for multiple inclined plunging
jet(s) within a scatter of ±15 percent. The relationship will be quite
useful in scale-up and in deciding optimum configuration of multiple
inclined plunging jet aeration system.
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: Taking the provincial capital, labor and energy as
inputs, regional GDP as output from 1995 to 2007, the paper
quantifies the vertical and lateral energy saving potential by
introducing the radial adjustment and slack adjustment of DEA. The
results show that by the vertical, the achievement of energy saving in
2007 is better than their respective historical performances. By
horizontal, in 2007 it can be found that Tianjin, Liaoning, Shanghai
and Yunnan do better in energy saving than other provinces. In
national wide, the higher of energy efficiency, the larger of per capita
GDP and the proportion of the tertiary industry in the national
economy, the more open to the outside, the lower the energy saving
potential demonstrates, while the energy endowment has negative
effect on energy saving potential.
Abstract: A pilot plant for continuous flow microwave-assisted
chemical reaction combined with microreactors was developed and
water heating tests were conducted for evaluation of the developed
plant. We developed a microwave apparatus having a single
microwave generator that can heat reaction solutions in four reaction
fields simultaneously in order to increase throughput. We also
designed a four-branch waveguide using electromagnetic simulation,
and found that the transmission efficiency at 99%. Finally, we
developed the pilot plant using the developed microwave apparatus
and conducted water heating tests. The temperatures in the respective
reaction fields were controlled within ±1.1 K at 353.2 K. Moreover,
the energy absorption rates by the water were about 90% in the
respective reaction fields, whereas the energy absorption rate was
about 40% when 100 cm3 of water was heated by a commercially
available multimode microwave chemical reactor.
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 knee bracing steel frame (KBF) is a new kind of energy dissipating frame, which combines excellent ductility and lateral stiffness. In this framing system, a special form of diagonal brace connected to a knee element instead of beam-column joint, is investigated. Recently, a similar system was proposed and named as chevron knee bracing system (CKB) which in comparison with the former system has a better energy absorption characteristic and at the same time retains the elastic nature of the structures. Knee bracing can provide a stiffer bracing system but reduces the ductility of the steel frame. Chevron knee bracing can be employed to provide the desired ductility level for a design. In this article, relation between seismic performance and structural parameters of the two above mentioned systems are investigated and compared. Frames with similar dimensions but various heights in both systems are designed according to Iranian code of practice for seismic resistant design of building, and then based on a non-linear push over static analysis; the seismic parameters such as behavior factor and performance levels are compared.
Abstract: Anaerobic digestion process is one of the alternative
methods to convert organic waste into methane gas which is a fuel
and energy source. Activities of various kinds of microorganisms are
the main factor for anaerobic digestion which produces methane gas.
Therefore, in this study a modified Anaerobic Baffled Reactor (ABR)
with working volume of 50 liters was designed to identify the
microorganisms through biogas production. The mixture of 75%
kitchen waste and 25% sewage sludge was used as substrate.
Observations on microorganisms in the ABR showed that there exists
a small amount of protozoa (5%) and fungi (2%) in the system, but
almost 93% of the microorganism population consists of bacteria. It
is definitely clear that bacteria are responsible for anaerobic
biodegradation of kitchen waste. Results show that in the
acidification zone of the ABR (front compartments of reactor) fast
growing bacteria capable of growth at high substrate levels and
reduced pH was dominant. A shift to slower growing scavenging
bacteria that grow better at higher pH was occurring towards the end
of the reactor. Due to the ability of activity in acetate environment the
percentages of Methanococcus, Methanosarcina and Methanotrix
were higher than other kinds of methane former in the system.
Abstract: Emphasis on the advancement of new materials and technology has been there for the past few decades. The global development towards using cheap and durable materials from renewable resources contributes to sustainable development. An experimental investigation of mechanical behaviour of sisal fibre-reinforced concrete is reported for making a suitable building material in terms of reinforcement. Fibre reinforced Composite is one such material, which has reformed the concept of high strength. Sisal fibres are abundantly available in the hot areas. Sisal fibre has emerged as a reinforcing material for concretes, used in civil structures. In this work, properties such as hardness and tensile strength of sisal fibre reinforced cement composites with 6, 12, 18 and 24% by weight of sisal fibres were assessed. Sisal fibre reinforced cement composite slabs with long sisal fibres were manufactured using a cast hand lay up technique. Mechanical response was measured under tension. The high energy absorption capacity of the developed composite system was reflected in high toughness values under tension respectively.
Abstract: The economic and stable operation was affected
seriously by coal quality disturbance for power plants. Based on model
analysis, influence of the disturbance can be considered as gain change
of control system. Power capability coefficient of coal was
constructed to inhibit it. Accuracy of the coefficient was verified by
operating data. Then coal quality disturbance free system based on
gain scheduling was designed for coordinated control system.
Simulation showed that, the strategy improved control quality
obviously, and inhibited the coal quality disturbance.