Abstract: Maturity sensors are used to determine concrete strength by the non-destructive method. The method of placement of the maturity sensors determines their number required for a certain frame of a monolithic building. This paper proposes a cheap prototype of an embedded wireless sensor for monitoring concrete structures, as well as an alternative strategy for placing sensors based on the transitional boundaries of the temperature distribution of concrete curing, which were determined by building a heat map of the temperature distribution, where unknown values are calculated by the method of inverse distance weighing. The developed prototype can simultaneously measure temperature and relative humidity over a smartphone-controlled time interval. It implements a maturity method to assess the in-situ strength of concrete, which is considered an alternative to the traditional shock impulse and compression testing method used in Kazakhstan. The prototype was tested in laboratory and field conditions. The tests were aimed at studying the effect of internal and external temperature and relative humidity on concrete's strength gain. Based on an experimentally poured concrete slab with randomly integrated maturity sensors, it the transition boundaries form elliptical forms were determined. Temperature distribution over the largest diameter of the ellipses was plotted, resulting in correct and inverted parabolas. As a result, the distance between the closest opposite crossing points of the parabolas is accepted as the maximum permissible step for setting the maturity sensors. The proposed placement strategy can be applied to sensors that measure various continuous phenomena such as relative humidity. Prototype testing has also revealed Bluetooth inconvenience due to weak signal and inability to access multiple prototypes simultaneously. For this reason, further prototype upgrades are planned in the future work.
Abstract: In the present paper, a low cost, compact and modular Internet of Things (IoT) platform for air quality monitoring in urban areas is presented. This platform comprises of dedicated low cost, low power hardware and the associated embedded software that enable measurement of particles (PM2.5 and PM10), NO, CO, CO2 and O3 concentration in the air, along with relative temperature and humidity. This integrated platform acts as part of a greater air pollution data collecting wireless network that is able to monitor the air quality in various regions and neighborhoods of an urban area, by providing sensor measurements at a high rate that reaches up to one sample per second. It is therefore suitable for Big Data analysis applications such as air quality forecasts, weather forecasts and traffic prediction. The first real world test for the developed platform took place in Thessaloniki, Greece, where 16 devices were installed in various buildings in the city. In the near future, many more of these devices are going to be installed in the greater Thessaloniki area, giving a detailed air quality map of the city.
Abstract: Nowadays, sustainable development issues have a key role in the planning of the man-made environment. Ensuring this development means limiting the impact of human activity on nature. It is essential to secure healthy places and good living conditions. For these reasons, indoor air quality and building materials play a fundamental role in sustainable architectural projects. These factors significantly affect human health: they can radically change the quality of the internal environment and energy consumption. The use of natural materials such as earth has many beneficial aspects in comfort and indoor air quality. As well as advantages in the environmental impact of the construction, they ensure a low energy consumption. Since they are already present in nature, their production and use do not require a high-energy consumption. Furthermore, they have a high thermo-hygrometric capacity, being able to absorb moisture, contributing positively to indoor conditions. Indoor air quality is closely related to relative humidity. For these reasons, it can be affirmed that the use of earth materials guarantees a sustainable development and at the same time improves the health of the building users. This paper summarizes several researches that demonstrate the importance of indoor air quality for human health and how it strictly depends on the building materials used. Eco-efficient plasters are also considered: earth and ash mortar. The bibliography consulted has the objective of supporting future experimental and laboratory analyzes. It is necessary to carry on with research by the use of simulations and testing to confirm the hygrothermal properties of eco-efficient plasters and therefore their ability to improve indoor air quality.
Abstract: When long-term changes in normal weather patterns happen in a certain area, it generally could be identified as climate change. Concentration of principal's greenhouse gases such as carbon dioxide, nitrous oxide, methane, ozone, and water vapor will cause climate change and perhaps climate variability. Main climate factors are temperature, precipitation, air pressure, and humidity. Extreme events may be the result of the changing of carbon dioxide concentration levels in the atmosphere which cause a change in temperature. Extreme events in some ways will affect the productivity of crop and dairy livestock. In this research, the correlation of milk production and temperature as the main climate factor in ChaharMahal and Bakhtiari province in Iran has been considered. The methodology employed for this study consists, collect reports and published national and provincial data, available recorded data on climate factors and analyzing collected data using statistical software. Milk production in ChaharMahal and Bakhtiari province is in the same pattern as national milk production in Iran. According to the current study results, there is a significant negative correlation between milk production in ChaharMahal and Bakhtiari provinces and temperature as the main climate change factor.
Abstract: The rapidly increasing number of population in the limited area creates an effect on the idea of the improvement of the area to suit the environment and the needs of people. Faculty of architecture Chiang Mai University is also expanding in both variety fields of study and quality of education. In 2020, the new department will be introduced in the faculty which is Department of Landscape Architecture. With the limitation of the area in the existing building, the faculty plan to renovate some parts of its school for anticipates the number of students who will join the program in the next two years. As a result, the old wooden workshop area is selected to be renovated as student studio space. With such condition, it is necessary to study the restriction and the distinctive environment of the site prior to the improvement in order to find ways to manage the existing space due to the fact that the primary functions that have been practiced in the site, an old wooden workshop space and the new function, studio space, are too different. 72.9% of the annual times in the room are considered to be out of the thermal comfort condition with high relative humidity. This causes non-comfort condition for occupants which could promote mould growth. This study aims to analyze thermal comfort condition in the Landscape Learning Studio Area for finding the solution to improve indoor air quality and respond to local conditions. The research methodology will be in two parts: 1) field gathering data on the case study 2) analysis and finding the solution of improving indoor air quality. The result of the survey indicated that the room needs to solve non-comfort condition problem. This can be divided into two ways which are raising ventilation and indoor temperature, e.g. improving building design and stack driven ventilation, using fan for enhancing more internal ventilation.
Abstract: Evaporative coolers has a minimum potential to reach the wet-bulb temperature of intake air which is not enough to handle a large cooling load; therefore, it is not a feasible option to overcome cooling requirement of a building. The invention of Maisotsenko (M) cycle has led evaporative cooling technology to reach the sub-wet-bulb temperature of the intake air; therefore, it brings an innovation in evaporative cooling techniques. In this work, we developed a mathematical model of the Maisotsenko based air cooler by applying energy and mass balance laws on different air channels. The governing ordinary differential equations are discretized and simulated on MATLAB. The temperature and the humidity plots are shown in the simulation results. A parametric study is conducted by varying working air inlet conditions (temperature and humidity), inlet air velocity, geometric parameters and water temperature. The influence of these aforementioned parameters on the cooling effectiveness of the HMX is reported. Results have shown that the effectiveness of the M-Cycle is increased by increasing the ambient temperature and decreasing absolute humidity. An air velocity of 0.5 m/sec and a channel height of 6-8mm is recommended.
Abstract: This paper studies the effect of ambient conditions on the performance of a 285 MW gas turbine unit using the exergy concept. Based on the available exergy balance models developed, a computer program has been constructed to investigate the performance of the power plant under varying ambient temperature and relative humidity conditions. The variations of ambient temperature range from zero to 50 ºC and the relative humidity ranges from zero to 100%, while the unit load kept constant at 100% of the design load. The exergy destruction ratio and exergy efficiency are determined for each component and for the entire plant. The results show a moderate increase in the total exergy destruction ratio of the plant from 62.05% to 65.20%, while the overall exergy efficiency decrease from 38.2% to 34.8% as the ambient temperature increases from zero to 50 ºC at all relative humidity values. Furthermore, an increase of 1 ºC in ambient temperature leads to 0.063% increase in the total exergy destruction ratio and 0.07% decrease in the overall exergy efficiency. The relative humidity has a remarkable influence at higher ambient temperature values on the exergy destruction ratio of combustion chamber and on exergy loss ratio of the exhaust gas but almost no effect on the total exergy destruction ratio and overall exergy efficiency. At 50 ºC ambient temperature, the exergy destruction ratio of the combustion chamber increases from 30% to 52% while the exergy loss ratio of the exhaust gas decreases from 28% to 8% as the relative humidity increases from zero to 100%. In addition, exergy analysis reveals that the combustion chamber and exhaust gas are the main source of irreversibility in the gas turbine unit. It is also identified that the exergy efficiency and exergy destruction ratio are considerably dependent on the variations in the ambient air temperature and relative humidity. Therefore, the incorporation of the existing gas turbine plant with inlet air cooling and humidifier technologies should be considered seriously.
Abstract: This paper is to formulate a mathematical model to predict the amounts of the emissions produced from the combustion process of the gas turbine unit of the jet engine. These emissions have bad impacts on the environment if they are out of standards, which cause real threats to all type of life on the earth. The amounts of the emissions from the gas turbine engine are functions to many operational and design factors. In landing-takeoff (LTO) these amounts are not the same as in taxi or cruise of the plane using jet engines, because of the difference in the activity period during these operating modes. These emissions can be affected by several physical and chemical variables, such as fuel type, fuel to air ratio or equivalence ratio, flame temperature, combustion pressure, in addition to some inlet conditions such as ambient temperature and air humidity. To study the influence of these variables on the amounts of these emissions during the combustion process in the gas turbine unit, a computer program has been developed by using the visual basic 6 software. Here, the analysis of the combustion process is carried out by considering it as a chemical reaction with shifting equilibrium to find the products of the combustion of the octane fuel, at different equivalence ratios, compressor pressure ratios (CPR) and combustion temperatures. The results obtained have shown that there is noticeable influence of the equivalence ratio, CPR, and the combustion temperature on the amounts of the main emissions which are considered pollutants, such as CO, CO2 and NO.
Abstract: This article presents gate-voltage controlled humidity sensing performance of vanadium dioxide nanoparticles prepared from NH4VO3 precursor using microwave irradiation technique. The X-ray diffraction, transmission electron diffraction, and Raman analyses reveal the formation of VO2 (B) with V2O5 and an amorphous phase. The BET surface area is found to be 67.67 m2/g. The humidity sensing measurements using the patented lateral-gate MOSFET configuration was carried out. The results show the optimum response at 5 V up to 8 V of gate voltages for 10 to 80% of relative humidity. The dose-response equation reveals the enhanced resilience of the gated VO2 sensor which may saturate above 272% humidity. The response and recovery times are remarkably much faster (about 60 s) than in non-gated VO2 sensors which normally show response and recovery times of the order of 5 minutes (300 s).
Abstract: Agriculture is the major occupation in India and forms the backbone of Indian economy in which irrigation plays a crucial role for increasing the quality and quantity of crop yield. In spite of many revolutionary advancements in agriculture, there has not been a dramatic increase in agricultural performance. Lack of irrigation infrastructure and agricultural knowledge are the critical factors influencing agricultural performance. However, by using advanced agricultural equipment, the effect of these factors can be curtailed. The presented system aims at increasing the yield of crops by using an intelligent irrigation controller that makes use of wireless sensors. Sensors are used to monitor primary parameters such as soil moisture, soil pH, temperature and humidity. Irrigation decisions are taken based on the sensed data and the type of crop being grown. The system provides a mobile application in which farmers can remotely monitor and control the irrigation system. Also, the water pump is protected against damages due to voltage variations and dry running.
Abstract: The United Arab Emirates (UAE) is significantly dependent on desalinated water and groundwater resource, which is expensive and highly energy intensive. Despite the scarce water resource, stagnates only 54% of the recycled water was reused in 2012, and due to the lack of infrastructure to reuse the recycled water, the portion is expected to decrease with growing water usage. In this study, an “Oasis” complex comprised of Sustainable Farming Compartments (SFC) was proposed for reusing treated wastewater. The wastewater is used to decrease the ambient temperature of the SFC via an evaporative cooler. The SFC prototype was designed, built, and tested in an environmentally controlled laboratory and field site to evaluate the feasibility and effectiveness of the SFC subjected to various climatic conditions in Abu Dhabi. Based on the experimental results, the temperature drop achieved in the SFC in the laboratory and field site were5 ̊C from 22 ̊C and 7- 15 ̊C (from 33-45 ̊C to average 28 ̊C at relative humidity < 50%), respectively. An energy simulation using TRNSYS was performed to extend and validate the results obtained from the experiment. The results from the energy simulation and experiments show statistically close agreement. The total power consumption of the SFC system was approximately three and a half times lower than that of an electrical air conditioner. Therefore, by using treated wastewater, the SFC has a promising prospect to solve Abu Dhabi’s ecological concern related to desertification and wind erosion.
Abstract: To evaluate the vigor of wheat seeds and stress of
premature aging effects on germination percentage, root length and
shoot length of five wheat cultivars that include Vynak, Karkheh,
Chamran, Star and Kavir which underwent a period of zero, two,
three, four days in terms of premature aging with 41°C temperature
and 100% relative humidity. Seed germination percentage, root
length and shoot length in these conditions were measured. This
experiment was conducted as a factorial completely randomized
design with four replications in laboratory conditions. The results
showed that each of aging treatments used in this experiment can be
used to detect differences in vigor of wheat varieties. Wheat cultivars
illustrated significant differences in germination percentage, root
length and shoot length in terms of premature aging. The wheat
cultivars; Astar and Vynak had maximum germination percentage
and Karkheh, respectively Kavir and Chamran had lowest percentage
of seed germination. Reactions of root and shoot length of wheat
cultivars was also different. The results showed that the seeds with a
stronger vigor affected less in premature aging condition and the
difference between the percentage of seed germination under normal
conditions and stress was significant and the seeds with the weaker
vigor were more sensitive to the premature aging stress and the
premature aging had more severe negative impact on seed vigor.
Abstract: Understanding the behavior of airflow in a room is essential for building designers to provide the most efficient design of ventilation system, and having acceptable indoor air quality. This trend is the motive to solve the relationship between airflow parameters and thermal comfort. This paper investigates airflow characteristics, indoor air quality (IAQ), and the thermal comfort (TC) in a ventilated room with a displacement ventilation system using three dimensional CFD code [AirPak 2.0.6]. After validation of the code, a numerical study is executed for a typical room with dimensions of 5m by 3m by 3m height according to a variety of supply air velocities, supply air temperature and supply air relative humidity. The finite volume method and the indoor zero equation turbulence models are employed for solving the governing equations numerically. The temperature field and the mean age of air (MAA) in the modeled room for a displacement ventilation system are determined according to a variety of the above parameters. The variable air volume (VAV) systems with different supply air velocity are applicable to control room air temperature for a displacement ventilation system.
Abstract: A numerical study has been conducted to investigate the influence of fin pitch and relative humidity on the heat transfer performance of the fin-and-tube heat exchangers having plain fin geometry under dehumidifying conditions. The analysis is done using the ratio between the heat transfer coefficients in totally wet conditions and those in totally dry conditions using the appropriate correlations for both dry and wet conditions. For a constant relative humidity, it is found that the heat transfer coefficient increases with the increase of the air frontal velocity. By contrast, the fin efficiency decreases when the face velocity is increased. Apparently, this phenomenon is attributed to the path of condensate drainage. For the influence of relative humidity, the results showed an increase in heat transfer performance and a decrease in wet fin efficiency when relative humidity increases. This is due to the higher amount of mass transfer encountered at higher relative humidity. However, it is found that the effect of fin pitch on the heat transfer performance depends strongly on the face velocity. At lower frontal velocity the heat transfer increases with fin pitch. Conversely, an increase in fin pitch gives lower heat transfer coefficients when air velocity is increased.
Abstract: Quality control in ceramic tile manufacturing is hard, labor intensive and it is performed in a harsh industrial environment with noise, extreme temperature and humidity. It can be divided into color analysis, dimension verification, and surface defect detection, which is the main purpose of our work. Defects detection is still based on the judgment of human operators while most of the other manufacturing activities are automated so, our work is a quality control enhancement by integrating a visual control stage using image processing and morphological operation techniques before the packing operation to improve the homogeneity of batches received by final users.
Abstract: The determination of sugars in foods is very
significant. Their relation in fact, can affect the chemical and
sensorial quality of the matrix (e.g., sweetness, pH, total acidity,
microbial stability, global acceptability) and can provide information
on food to optimize several selected technological processes. Three
stages of ripeness (green, yellow and red) of tomatoes (Lycopersicon
Esculentum cv. Elegance) at different harvest dates were evaluated.
Fruit from all harvests were exposed to different of ozone doses
(0.25, 0.50 and 1 mg O3/g tomatoes) and clean air for 5 day at 15
°C±2 and 90-95 % relative humidity. Then, fruits were submitted for
extraction and analysis after a day from the finish of exposure of each
stage. The concentrations of the glucose and fructose increased in the
tomatoes which were subjected to ozone treatments.
Abstract: This study investigated the use of modified
atmosphere packaging (MAP) and different packaging to extend the
shelf life of Barbari flat bread. Three atmospheres including 70%CO2
and 30%N2, 50% CO2 and 50%N2 and a normal air as control were
used. The bread samples were packaged in three type pouches. The
shelf life was determined by appearance of mold and yeast (M +Y) in
Barbari bread samples stored at 25 ± 1°C and 38 ± 2% relative
humidity. The results showed that it is possible to prolong the shelf
life of Barbari bread from four days to about 21 days by using
modified atmosphere packaging with high carbon dioxide
concentration and high-barrier laminated and vacuum bags packages.
However, the hardness of samples kept in MAP increase significantly
by increase of carbon dioxide concentration. The correlation
coefficient (r) between headspace CO2 concentration and hardness
was 0.997, 0.997 and 0.599 for A, B and C packaging respectively.
High negative correlation coefficients were found between the crumb
moisture and the hardness values in various packaging. There were
significant negative correlation coefficients between sensory
parameters and hardness of texture.
Abstract: Adhesion strength of exterior or interior coating of
steel pipes is too important. Increasing of coating adhesion on
surfaces can increase the life time of coating, safety factor of
transmitting line pipe and decreasing the rate of corrosion and costs.
Preparation of steel pipe surfaces before doing the coating process is
done by shot and grit blasting. This is a mechanical way to do it.
Some effective parameters on that process, are particle size of
abrasives, distance to surface, rate of abrasive flow, abrasive physical
properties, shapes, selection of abrasive, kind of machine and its
power, standard of surface cleanness degree, roughness, time of
blasting and weather humidity. This search intended to find some
better conditions which improve the surface preparation, adhesion
strength and corrosion resistance of coating. So, this paper has
studied the effect of varying abrasive flow rate, changing the
abrasive particle size, time of surface blasting on steel surface
roughness and over blasting on it by using the centrifugal blasting
machine. After preparation of numbers of steel samples (according to
API 5L X52) and applying epoxy powder coating on them, to
compare strength adhesion of coating by Pull-Off test. The results
have shown that, increasing the abrasive particles size and flow rate,
can increase the steel surface roughness and coating adhesion
strength but increasing the blasting time can do surface over blasting
and increasing surface temperature and hardness too, change,
decreasing steel surface roughness and coating adhesion strength.
Abstract: In the present work an investigation of the effects of
the air frontal velocity, relative humidity and dry air temperature on
the heat transfer characteristics of plain finned tube evaporator has
been conducted. Using an appropriate correlation for the air side heat
transfer coefficient the temperature distribution along the fin surface
was calculated using a dimensionless temperature distribution. For a
constant relative humidity and bulb temperature, it is found that the
temperature distribution decreases with increasing air frontal
velocity. Apparently, it is attributed to the condensate water film
flowing over the fin surface. When dry air temperature and face
velocity are being kept constant, the temperature distribution
decreases with the increase of inlet relative humidity. An increase in
the inlet relative humidity is accompanied by a higher amount of
moisture on the fin surface. This results in a higher amount of latent
heat transfer which involves higher fin surface temperature. For the
influence of dry air temperature, the results here show an increase in
the dimensionless temperature parameter with a decrease in bulb
temperature. Increasing bulb temperature leads to higher amount of
sensible and latent heat transfer when other conditions remain
constant.
Abstract: Thirty three re-wetting tests were conducted at
different combinations of temperatures (5.7- 46.30C) and relative
humidites (48.2-88.6%) with barley. Two most commonly used thinlayer
drying and rewetting models i.e. Page and Diffusion were
compared for their ability to the fit the experimental re-wetting data
based on the standard error of estimate (SEE) of the measured and
simulated moisture contents. The comparison shows both the Page
and Diffusion models fit the re-wetting experimental data of barley
well. The average SEE values for the Page and Diffusion models
were 0.176 % d.b. and 0.199 % d.b., respectively. The Page and
Diffusion models were found to be most suitable equations, to
describe the thin-layer re-wetting characteristics of barley over a
typically five day re-wetting. These two models can be used for the
simulation of deep-bed re-wetting of barley occurring during
ventilated storage and deep bed drying.