Abstract: The previous researches focused on the influence of
anthropogenic greenhouse gases exerting global warming, but not
consider whether desert sand may warm the planet, this could be
improved by accounting for sand's physical and geometric properties.
Here we show, sand particles (because of their geometry) at the desert
surface form an extended surface of up to 1 + π/4 times the planar area
of the desert that can contact sunlight, and at shallow depths of the
desert form another extended surface of at least 1 + π times the planar
area that can contact air. Based on this feature, an enhanced heat
exchange system between sunlight, desert sand, and air in the spaces
between sand particles could be built up automatically, which can
increase capture of solar energy, leading to rapid heating of the sand
particles, and then the heating of sand particles will dramatically heat
the air between sand particles. The thermodynamics of deserts may
thus have contributed to global warming, especially significant to
future global warming if the current desertification continues to
expand.
Abstract: Pretreatment is an essential step in the conversion of
lignocellulosic biomass to fermentable sugar that used for biobutanol
production. Among pretreatment processes, microwave is considered
to improve pretreatment efficiency due to its high heating efficiency,
easy operation, and easily to combine with chemical reaction. The
main objectives of this work are to investigate the feasibility of
microwave pretreatment to enhance enzymatic hydrolysis of
corncobs and to determine the optimal conditions using response
surface methodology. Corncobs were pretreated via two-stage
pretreatment in dilute sodium hydroxide (2 %) followed by dilute
sulfuric acid 1 %. Pretreated corncobs were subjected to enzymatic
hydrolysis to produce reducing sugar. Statistical experimental design
was used to optimize pretreatment parameters including temperature,
residence time and solid-to-liquid ratio to achieve the highest amount
of glucose. The results revealed that solid-to-liquid ratio and
temperature had a significant effect on the amount of glucose.
Abstract: This study evaluated the microbiological quality
and the sensory characteristics of carp fillets processed by the
sousvide method when stored at 2 and 10 °C. Four different
combinations of sauced–storage were studied then stored at 2 or 10
°C was evaluate periodically sensory, microbiological and
chemical quality. Batches stored at 2 °C had lower growth rates of
mesophiles and psychrotrophs. Moreover, these counts decreased
by increasing the heating temperature and time. Staphylococcus
aureus, Bacillus cereus, Clostridium perfringens and Listeria
monocytogenes were not found in any of the samples. The heat
treatment of 90 °C for 15 min and sauced was the most effective to
ensure the safety and extend the shelf-life of sousvide carp
preserving its sensory characteristics. This study establishes the
microbiological quality of sous vide carp and emphasizes the
relevance of the raw materials, heat treatment and storage
temperature to ensure the safety of the product.
Abstract: The ability to predict an accurate temperature
distribution requires the knowledge of the losses, the thermal
characteristics of the materials, and the cooling conditions, all of
which are very difficult to quantify. In this paper, the impact of the
effects of iron and copper losses are investigated separately and
their effects on the heating in various points of the stator of an
induction motor, is highlighted by using two simple tests. In addition,
the effect of a defect, such as an open circuit in a phase of the stator,
on the heating is also obtained by a no-load test.
The squirrel cage induction motor is rated at 2.2 kW; 380 V; 5.2
A; Δ connected; 50 Hz; 1420 rpm and the class of insulation F, has
been thermally tested under several load conditions. Several
thermocouples were placed in strategic points of the stator.
Abstract: Viscous heating becomes significant in the high speed
resin coating process of glass fibers for optical fiber manufacturing.
This study focuses on the coating resin flows inside the capillary
coating die of optical fiber coating applicator and they are numerically
simulated to examine the effects of viscous heating and subsequent
temperature increase in coating resin. Resin flows are driven by fast
moving glass fiber and the pressurization at the coating die inlet, while
the temperature dependent viscosity of liquid coating resin plays an
important role in the resin flow. It is found that the severe viscous
heating near the coating die wall profoundly alters the radial velocity
profiles and that the increase of final coating thickness by die
pressurization is amplified if viscous heating is present.
Abstract: The aim of this study is to develop mathematical
relationships for the performance parameter brake thermal efficiency
(BTE) and emission parameter nitrogen oxides (NOx) for the various
esters of vegetable oils used as CI engine fuel. The BTE is an
important performance parameter defining the ability of engine to
utilize the energy supplied and power developed similarly it is
indication of efficiency of fuels used. The esters of cottonseed oil,
soybean oil, jatropha oil and hingan oil are prepared using
transesterification process and characterized for their physical and
main fuel properties including viscosity, density, flash point and
higher heating value using standard test methods. These esters are
tried as CI engine fuel to analyze the performance and emission
parameters in comparison to diesel. The results of the study indicate
that esters as a fuel does not differ greatly with that of diesel in
properties. The CI engine performance with esters as fuel is in line
with the diesel where as the emission parameters are reduced with the
use of esters.
The correlation developed between BTE and brake power(BP),
gross calorific value(CV), air-fuel ratio(A/F), heat carried away by
cooling water(HCW). Another equation is developed between the
NOx emission and CO, HC, smoke density (SD), exhaust gas
temperature (EGT). The equations are verified by comparing the
observed and calculated values which gives the coefficient of
correlation of 0.99 and 0.96 for the BTE and NOx equations
respectively.
Abstract: Oxide scale thickness measurements are used in assessing the life of different components operating at high temperature environment. Such measurements provide an approximation for the temperature inside components such as reheater and superheater tubes. A number of failures were encountered in one of the boilers in one of Kuwaiti power plants. These failure were mainly in the first row of the primary super heater tubes, therefore, the specialized engineer decide to replace them during the annual shutdown. As a tool for failure analysis, oxide scale thickness measurement were used to investigate the temperature distribution in these tubes. In this paper, the oxide scale thickness of these tubes were measured and used for analysis. The measurements provide an illustration of the distribution of heat transfer of the primary superheater tubes in the boiler system. Remarks and analysis about the design of the boiler are also provided.
Abstract: A numerical study on the influence of forward-facing
cavity length upon forward-facing cavity and opposing jet combined
thermal protection system (TPS) cooling efficiency under hypersonic
flow is conducted, by means of which the flow field parameters, heat
flux distribution along the outer body surface are obtained. The
numerical simulation results are validated by experiments and the
cooling effect of the combined TPS with different cavity length is
analyzed. The numerical results show that the combined configuration
dose well in cooling the nose of the hypersonic vehicle. The deeper the
cavity is, the weaker the heat flux is. The recirculation region plays a
key role for the reduction of the aerodynamic heating.
Abstract: The induction hardening machines are utilized in
the industries which modify machine parts and tools needed to
achieve high ware resistance. This paper describes the model of
induction heating process design of inverter circuit and the results
of induction surface hardening of heating coil. In the design of
heating coil, the shape and the turn numbers of the coil are very
important design factors because they decide the overall operating
performance of induction heater including resonant frequency, Q
factor, efficiency and power factor. The performance will be tested
by experiments in some cases high frequency induction hardening
machine.
Abstract: A simple model for studying convectional lifting
processes in the tropics is described in this paper with some tests of
the model in dry air. The model consists of the density equation, the
wind equation, the vertical velocity equation, and the temperature
equation. The model domain is two-dimensional with length 100 km
and height 17.5 km. Plan for experiments to investigate the effects of
the heating surface, the deep convection approximation and the
treatment of velocities at the boundaries are discussed. Equations for
the simplified treatment of moisture in the atmosphere in future
numerical experiments are also given.
Abstract: A hotel mainly uses its energy on water heating, space
heating, refrigeration, space cooling, cooking, lighting and other
building services. A number of 4-5 stars hotels in Auckland city are
selected for this study. Comparing with the energy used for others,
the energy used for the internal space thermal control (e.g. internal
space heating) is more closely related to the hotel building itself.
This study not only investigates relationship between annual energy
(and winter energy) consumptions and building design data but also
relationships between winter extra energy consumption and building
design data. This study is to identify the major design factors that
significantly impact hotel energy consumption for improving the
future hotel design for energy efficient.
Abstract: Air conditioning systems of houses consume large
quantity of electricity. To reducing energy consumption for air
conditioning purposes it is becoming attractive the use of evaporative
cooling air conditioning which is less energy consuming compared to
air chillers. But, it is obvious that higher energy efficiency of
evaporative cooling is not enough to judge whether evaporative
cooling economically is competitive with other types of cooling
systems. To proving the higher energy efficiency and cost
effectiveness of the evaporative cooling competitive analysis of
various types of cooling system should be accomplished. For noted
purpose optimization mathematical model for each system should be
composed based on system approach analysis. In this paper different
types of evaporative cooling-heating systems are discussed and
methods for increasing their energy efficiency and as well as
determining of their design parameters are developed. The
optimization mathematical models for each of them are composed
with help of which least specific costs for each of them are reviled.
The comparison of specific costs proved that the most efficient and
cost effective is considered the “direct evaporating" system if it is
applicable for given climatic conditions. Next more universal and
applicable for many climatic conditions system providing least cost
of heating and cooling is considered the “direct evaporating" system.
Abstract: In this research a mathematical model for direct
oxidization of hydrogen sulfide into elemental sulfur in a fluidized
bed reactor with external circulation was developed. As the catalyst
is deactivated in the fluidized bed, it might be placed in a reduction
tank in order to remove sulfur through heating above its dew point.
The reactor model demonstrated via MATLAB software. It was
shown that variations of H2S conversion as well as; products formed
were reasonable in comparison with corresponding results of a fixed
bed reactor. Through analyzing results of this model, it became
possible to propose the main optimized operating conditions for the
process considered. These conditions included; the temperature range
of 100-130ºC and utilizing the catalyst as much as possible providing
the highest bed density respect to dimensions of bed, economical
aspects that the bed ever remained in fluidized mode. A high active
and stable catalyst under the optimum conditions exhibited 100%
conversion in a fluidized bed reactor.
Abstract: Today, building automation is advancing from simple
monitoring and control tasks of lightning and heating towards more
and more complex applications that require a dynamic perception
and interpretation of different scenes occurring in a building. Current
approaches cannot handle these newly upcoming demands. In this
article, a bionically inspired approach for multimodal, dynamic scene
perception and interpretation is presented, which is based on neuroscientific
and neuro-psychological research findings about the perceptual
system of the human brain. This approach bases on data from diverse
sensory modalities being processed in a so-called neuro-symbolic
network. With its parallel structure and with its basic elements being
information processing and storing units at the same time, a very
efficient method for scene perception is provided overcoming the
problems and bottlenecks of classical dynamic scene interpretation
systems.
Abstract: Air conditioning is mainly to be used as human
comfort medium. It has been use more often in country in which the
daily temperatures are high. In scientific, air conditioning is defined
as a process of controlling the moisture, cooling, heating and cleaning
air. Without proper estimation of cooling load, big amount of waste
energy been used because of unsuitable of air conditioning system are
not considering to overcoming heat gains from surrounding. This is
due to the size of the room is too big and the air conditioning has to
use more energy to cool the room and the air conditioning is too
small for the room. The studies are basically to develop a program to
calculate cooling load. Through this study it is easy to calculate
cooling load estimation. Furthermore it-s help to compare the cooling
load estimation by hourly and yearly. Base on the last study that been
done, the developed software are not user-friendly. For individual
without proper knowledge of calculating cooling load estimation
might be problem. Easy excess and user-friendly should be the main
objective to design something. This program will allow cooling load
able be estimate by any users rather than estimation by using rule of
thumb. Several of limitation of case study is judged to sure it-s
meeting to Malaysia building specification. Finally validation is done
by comparison manual calculation and by developed program.
Abstract: The tubes in an Ammonia primary reformer furnace
operate close to the limits of materials technology in terms of the
stress induced as a result of very high temperatures, combined with
large differential pressures across the tube wall. Operation at tube
wall temperatures significantly above design can result in a rapid
increase in the number of tube failures, since tube life is very
sensitive to the absolute operating temperature of the tube. Clearly it
is important to measure tube wall temperatures accurately in order to
prevent premature tube failure by overheating.. In the present study,
the catalyst tubes in an Ammonia primary reformer has been modeled
taking into consideration heat, mass and momentum transfer as well
as reformer characteristics.. The investigations concern the effects of
tube characteristics and superficial tube wall temperatures on of the
percentage of heat flux, unconverted methane and production of
Hydrogen for various values of steam to carbon ratios. The results
show the impact of catalyst tubes length and diameters on the
performance of operating parameters in ammonia primary reformers.
Abstract: Continuous measurements and multivariate methods are applied in researching the effects of energy consumption on indoor air quality (IAQ) in a Finnish one-family house. Measured data used in this study was collected continuously in a house in Kuopio, Eastern Finland, during fourteen months long period. Consumption parameters measured were the consumptions of district heat, electricity and water. Indoor parameters gathered were temperature, relative humidity (RH), the concentrations of carbon dioxide (CO2) and carbon monoxide (CO) and differential air pressure. In this study, self-organizing map (SOM) and Sammon's mapping were applied to resolve the effects of energy consumption on indoor air quality. Namely, the SOM was qualified as a suitable method having a property to summarize the multivariable dependencies into easily observable two-dimensional map. Accompanying that, the Sammon's mapping method was used to cluster pre-processed data to find similarities of the variables, expressing distances and groups in the data. The methods used were able to distinguish 7 different clusters characterizing indoor air quality and energy efficiency in the study house. The results indicate, that the cost implications in euros of heating and electricity energy vary according to the differential pressure, concentration of carbon dioxide, temperature and season.
Abstract: To calculate the temperature distribution of the slab in
a hot rolled reheating furnace a mathematical model has been
developed by considering the thermal radiation in the furnace and
transient conduction in the slab. The furnace is modeled as radiating
medium with spatially varying temperature. Radiative heat flux within
the furnace including the effect of furnace walls, combustion gases,
skid beams and buttons is calculated using the FVM and is applied as
the boundary condition of the transient conduction equation of the
slab. After determining the slab emissivity by comparison between
simulation and experimental work, variation of heating characteristics
in the slab is investigated in the case of changing furnace temperature
with various time and the slab residence time is optimized with this
evaluation.
Abstract: The daily increase of organic waste materials resulting
from different activities in the country is one of the main factors for
the pollution of environment. Today, with regard to the low level of
the output of using traditional methods, the high cost of disposal
waste materials and environmental pollutions, the use of modern
methods such as anaerobic digestion for the production of biogas has
been prevailing. The collected biogas from the process of anaerobic
digestion, as a renewable energy source similar to natural gas but
with a less methane and heating value is usable. Today, with the help
of technologies of filtration and proper preparation, access to biogas
with features fully similar to natural gas has become possible. At
present biogas is one of the main sources of supplying electrical and
thermal energy and also an appropriate option to be used in four
stroke engine, diesel engine, sterling engine, gas turbine, gas micro
turbine and fuel cell to produce electricity. The use of biogas for
different reasons which returns to socio-economic and environmental
advantages has been noticed in CHP for the production of energy in
the world. The production of biogas from the technology of anaerobic
digestion and its application in CHP power plants in Iran can not only
supply part of the energy demands in the country, but it can
materialize moving in line with the sustainable development. In this
article, the necessity of the development of CHP plants with biogas
fuels in the country will be dealt based on studies performed from the
economic, environmental and social aspects. Also to prove the
importance of the establishment of these kinds of power plants from
the economic point of view, necessary calculations has been done as
a case study for a CHP power plant with a biogas fuel.
Abstract: Temperature is one of the most principle factors affects aquaculture system. It can cause stress and mortality or superior environment for growth and reproduction. This paper presents the control of pond water temperature using artificial intelligence technique. The water temperature is very important parameter for shrimp growth. The required temperature for optimal growth is 34oC, if temperature increase up to 38oC it cause death of the shrimp, so it is important to control water temperature. Solar thermal water heating system is designed to supply an aquaculture pond with the required hot water in Mersa Matruh in Egypt. Neural networks are massively parallel processors that have the ability to learn patterns through a training experience. Because of this feature, they are often well suited for modeling complex and non-linear processes such as those commonly found in the heating system. Artificial neural network is proposed to control water temperature due to Artificial intelligence (AI) techniques are becoming useful as alternate approaches to conventional techniques. They have been used to solve complicated practical problems. Moreover this paper introduces a complete mathematical modeling and MATLAB SIMULINK model for the aquaculture system. The simulation results indicate that, the control unit success in keeping water temperature constant at the desired temperature by controlling the hot water flow rate.