Search results for: vertical earthquake coefficient

Authors: Jeong Hong Kim, Ju Wan Kang

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Objective: Histamine skin prick testing is most commonly used to diagnose immunoglobulin E (IgE)-mediated allergic diseases, and histamine reactivity is used as a standardized positive control in the interpretation of a skin prick test. However, reactivity to histamine differs among individuals for reasons that are poorly understood. The present study aimed to evaluate the potential association between body mass index (BMI) and histamine skin reactivity in children. Methods: A total of 451 children (246 boys, 205 girls) aged 7–8 years were enrolled in this study. The skin prick test was performed with 26 aeroallergens commonly found in Korea. Other information was collected, including sex, age, BMI, parental allergy history, and parental smoking status. Multivariate analysis was used to confirm the association between histamine skin reactivity and BMI. Results: The histamine wheal size was revealed to be associated with BMI (Spearman's Rho 0.161, p < 0.001). This association was confirmed by multivariate analysis, after adjusting for sex, age, parental allergy history, parental smoking status, and allergic sensitization (coefficient B 0.071, 95% confidence interval 0.030–0.112). Conclusions: Skin responses to histamine were primarily correlated with increased BMI. Further studies are needed to understand the clinical implication of BMI when interpreting the results of skin prick test.

Keywords: allergy, body mass index, histamine, skin prick test

Procedia PDF Downloads 361

Authors: Jameson McFarlane, Thorne J. McFarlane, Leon Bernard

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Social network sites (SNS) is an emerging phenomenon that is here to stay. The popularity and the ubiquity of the SNS technology are undeniable. Because most SNS are free and easy to use people from all walks of life and from almost any age are attracted to that technology. College age students are by far the largest segment of the population using SNS. Since most SNS have been adapted for mobile devices, not only do you find students using this technology in their study, while working on labs or on projects, a substantial number of students have been found to use SNS even while listening to lectures. This study found that SNS use has a significant negative impact on the grade point average of college students particularly in the first semester. However, this negative impact is greatly diminished by the end of the third semester partly because the students have adjusted satisfactorily to the challenges of college or because they have learned how to adequately manage their time. It was established that the kinds of activities the students are engaged in during the SNS use are the leading factor affecting academic performance. Of those activities, using SNS during a lecture or while studying is the foremost contributing factor to lower academic performance. This is due to “cognitive” or “information” bottleneck, a condition in which the students find it very difficult to multitask or to switch between resources leading to inefficiency in information retention and thus, educational performance.

Keywords: social network sites, social network analysis, regression coefficient, psychological engagement

Procedia PDF Downloads 179

Authors: Y. K. Leong, J. C. W. Lan, H. S. Loh, P. L. Show

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Being biodegradable, non-toxic, renewable and have similar or better properties as commercial plastics, polyhydroxy alkanoates (PHAs) can be a potential game changer in the polymer industry. PHAs are the biodegradable polymer produced by bacteria, which are in interest as a sustainable alternative to petrochemical-derived plastics; however, its commercial value has significantly limited by high production and recovery cost of PHA. Aqueous two-phase system (ATPS) offers different chemical and physical environments, which contains about 80-90% water delivers an excellent environment for partitioning of cells, cell organelles and biologically active substances. Extractive bioconversion via ATPS allows the integration of PHA upstream fermentation and downstream purification process, which reduces production steps and time, thus lead to cost reduction. The ability of Ralstonia eutropha to grow under different ATPS conditions was investigated for its potential to be used in a bioconversion system. Changes in tie-line length (TLL) and a volume ratio (Vr) were shown to have an effect on PHA partition coefficient. High PHA recovery yield of 65% with a relatively high purity of 73% was obtained in PEG 6000/Sodium sulphate system with 42.6 wt/wt % TLL and 1.25 Vr. Extractive bioconversion via ATPS is an attractive approach for the combination of PHA production and recovery process.

Keywords: aqueous two-phase system, extractive bioconversion, polyhydroxy alkanoates, purification

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Authors: Luqman Afolabi

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This paper measures the impacts of trade and institutions on environmental quality in Sub-Saharan Africa (SSA). To examine the direction and the magnitude of the effects, the study employs the pooled mean group (PMG) estimation technique on the panel data obtained from the World Bank’s World Development and Governance Indicators, between 1996 and 2018. The empirical estimates validate the environmental Kuznets curve hypothesis (EKC) for the region, even though there have been inconclusive results on the environment – growth nexus. Similarly, a positive coefficient is obtained on the impact of trade on the environment, while the impact of the institutional indicators produce mixed results. A significant policy implication is that the governments of the SSA countries pursue policies that tend to increase economic growth, so that pollutants may be reduced. Such policies may include the provision of incentives for sustainable growth-driven industries in the region. In addition, the governance infrastructures should be improved in such a way that appropriate penalties are imposed on the pollutants, while advanced technologies that have the potentials to reduce environmental degradation should be encouraged. Finally, it is imperative from these findings that the governments of the region should promote their trade relations and the competitiveness of their local industries in order to keep pace with the global markets.

Keywords: environmental quality, institutional quality sustainable development goals, trade

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Authors: Vishal Kumar Singh

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Bioprocess development is a time-constrained activity aimed at harnessing the full potential of culture performance in an ambience that is not natural to cells. Even with the use of chemically defined media and feeds, a significant amount of time is devoted in identifying the apt operating parameters. In addition, the scale-up of these processes is often accompanied by loss of antibody titer and product quality, which further delays the commercialization of the drug product. In such a scenario, the investigation of this disparity of culture performance is done by further experimentation at a smaller scale that is representative of at-scale production bioreactors. These scale-down model developments are also time-intensive. In this study, a computation fluid dynamics-based multi-objective scaling approach has been illustrated to speed up the process transfer. For the implementation of this approach, a transient multiphase water-air system has been studied in Ansys CFX to visualize the air bubble distribution and volumetric mass transfer coefficient (kLa) profiles, followed by the design of experiment based parametric optimization approach to define the operational space. The proposed approach is completely in silico and requires minimum experimentation, thereby rendering a high throughput to the overall process development.

Keywords: bioprocess development, scale up, scale down, computation fluid dynamics, multi-objective, Ansys CFX, design of experiment

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Authors: Birhanu Kassa

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The knowledge of temperature effect on index properties and, thus, the understanding of its behavior may be essential for a complete understanding of the various cases of Geotechnical Engineering problems and for conducting meaningful practical research, analysis, and design in tropical regions, such as the Ethiopian environment. The scarcity of the proper geotechnical information on the subsoil makes foundation and engineering works risk able, difficult, and sometimes hazardous. Seasonal variations, environmental effects, terrain challenges, and temperature effects all affect the quality of soil. Simada is a city which is found in south Gondar and it is developing rapidly both in horizontal and vertical construction. Rapid urbanization in the city area has led to an increased interest in the basic properties of soils that are present within the city area. There has been no previous research that looks into the effect of temperature on the investigation of clay soil index qualities in Simada. This work focuses mainly on investigating the Index and some other properties of soil in Simada Town with varying temperatures. To explore the influence of temperature change, samples were collected from various regions of the city, and routine laboratory tests were performed on the collected samples at various temperatures. Disturbed samples were taken at intervals where an average depth of 1.5-2m depths below natural ground level. The standard laboratory tests performed on all twenty-four soil samples were the water content, gradation analysis, Atterberg limits, specific gravity, and compaction test. All specimens were tested at different temperatures (25°C, 35 °C, 45 °C, 65 °C,75 and 105 °C). The variation of the plasticity characteristics of the soils has been determined based on the temperature variation. From the test result, we can conclude that temperature has a significant effect on the index properties of clay soil, in our case, red clay soil.

Keywords: airdried, oven dried, soils index properties, compaction test

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Authors: Aghamusa Azizov

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This study investigates the correlation between solar activity and sentiment in news media coverage, using a large-scale dataset of solar activity since 1750 and over 15 million articles from "The New York Times" dating from 1851 onwards. Employing Pearson's correlation coefficient and multiple Natural Language Processing (NLP) tools—TextBlob, Vader, and DistillBERT—the research examines the extent to which fluctuations in solar phenomena are reflected in the sentiment of historical news narratives. The findings reveal that the correlation between solar activity and media sentiment is generally negligible, suggesting a weak influence of solar patterns on the portrayal of events in news media. Notably, a moderate positive correlation was observed between the sentiments derived from TextBlob and Vader, indicating consistency across NLP tools. The analysis provides insights into the historical impact of solar activity on human affairs and highlights the importance of using multiple analytical methods to understand complex relationships in large datasets. The study contributes to the broader understanding of how extraterrestrial factors may intersect with media-reported events and underlines the intricate nature of interdisciplinary research in the data science and historical domains.

Keywords: solar activity correlation, media sentiment analysis, natural language processing, historical event patterns

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Authors: Biruk Wolde, Atalay Ayele, Yonatan Garkabo, Trufat Hailmariam, Zemenu Germewu

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A comprehensive three-dimensional (3D) geological modeling and engineering geological characterization of shallow subsurface soils and rocks are essential for a wide range of geotechnical and seismological engineering applications, particularly in urban environments. The spatial distribution and geological variation of the shallow subsurface of Addis Ababa city have not been studied so far in terms of geological and geotechnical modeling. This study aims at the construction of a 3D geological model, as well as provides awareness into the engineering geological characteristics of shallow subsurface soil and rock of Addis Ababa city. The 3D geological model was constructed by using more than 1500 geotechnical boreholes, well-drilling data, and geological maps. A well-known geostatistical kriging 3D interpolation algorithm was applied to visualize the spatial distribution and geological variation of the shallow subsurface. Due to the complex nature of geological formations, vertical and lateral variation of the geological profiles horizons-solid command has been selected via the Groundwater Modelling System (GMS) graphical user interface software. For the engineering geological characterization of typical soils and rocks, both index and engineering laboratory tests have been used. The geotechnical properties of soil and rocks vary from place to place due to the uneven nature of subsurface formations observed in the study areas. The constructed model ascertains the thickness, extent, and 3D distribution of the important geological units of the city. This study is the first comprehensive research work on 3D geological modeling and subsurface characterization of soils and rocks in Addis Ababa city, and the outcomes will be important for further future research on subsurface conditions in the city. Furthermore, these findings provide a reference for developing a geo-database for the city.

Keywords: 3d geological modeling, addis ababa, engineering geology, geostatistics, horizons-solid

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Authors: Maryam Jaberi, Siavosh Shayan, Mojtaba Yamani

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Habble-Rud River basin (HR), up to 100 km length, one of the largest watersheds which drain into deserts to the north of Central Iran (Dasht-e Kavir). This stream is oblique with the NE-SW trending, flow in the southern range of central Alborz Mountains and the northern border of Central Iran. The end of the ~17 km suddenly change direction and with the southern trending to have a morphology which meanders passes through the Alborz Mountain ridge and flows into the Garmsar plain where it forms one of the largest alluvial fans in Iran, i.e. the vast Garmsar alluvial fan with an area of 476 km2. This study was carried out through morphometric analyses, longitudinal river profiles, and study of geomorpholic evidence such as fluvial terraces, gypsum-salt domes, seismic data, and satellite images. This study aimed to investigate the changes in the pattern of rivers in the southern part of the HR river basin. The southern part of HR river basin located at the southern foothills of the Central Alborz is characterized the thrust faults (Sorkheh-Kalut and Garmsar faults), folds,diapirs and arid climate. The activity of more than 10 salt domes that belong to the Oligocene-Miocene period has considerably influenced the pattern of streams in this region. Dissolution of these domes has not only reduced the quality of water and soil resources, but also has led to the formation of badlands and gullies.Our results indicated that the pattern of rivers in the southern part of HR river basin was influenced by discharge of the HR river in Quaternary, geological structure, subsidence of Central Iran and vertical uplift of Alborz mountain. These agents caused the formation meanders in the southern part of the HR River and evaluation of the seasonal rivers like Shoor-Darre and Garmabsar.

Keywords: geomorphologic evaluation, rivers pattern, Habble-Rud River basin, seasonal rivers

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Authors: Jacinta Ifeoma Obidile

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The study sought to ascertain from the opinions of the business educators, effective strategies for funding public tertiary institutions in Anambra State Nigeria, for effective functioning and delivery. Funding of tertiary institutions has become so important following the dilapidated state of most of the public tertiary institutions in Nigeria. Tertiary institutions are known for the production of competitive and competent workforce in the nation. Considering the state of public tertiary institutions currently, one wonders if their objectives are achieved. Many scholars have identified funding as one of the major barriers to effective functioning of tertiary institutions. Although federal and state governments have been supporting the tertiary institutions, but their support seems not to be adequate. This study therefore ascertained from the perspective of business educators, other strategies for funding public tertiary institutions in Anambra State Nigeria, for effective functioning and delivery. Survey research design was adopted for the study. A total of 104 business educators from the public tertiary institutions in the State constituted the population. There was no sampling, hence the whole population was used. Structured questionnaire validated by three experts with a reliability coefficient of 0.82 was the instrument for data collection. Data collected were analyzed using mean and standard deviation. Findings from the study revealed that public-private partnership and external aids were among the strategies considered effective for funding public tertiary institutions. It was therefore recommended among others that associations like alumni should be strongly instituted in each of the public tertiary institutions so as to assist in the funding of tertiary institutions for effective functioning and delivery.

Keywords: strategies, funding, tertiary institutions, business educators

Procedia PDF Downloads 155

Authors: Mohammad Karimi, Magnus Heurlin, Lars Samuelson, Magnus Borgstrom, Hakan Pettersson

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Nanowire semiconductors are promising candidates for optoelectronic applications such as solar cells, photodetectors and lasers due to their quasi-1D geometry and large surface to volume ratio. The functional wavelength range of NW-based detectors is typically limited to the visible/near-infrared region. In this work, we present electrical and optical properties of IR photodetectors based on large square millimeter ensembles (>1million) of vertically processed semiconductor heterostructure nanowires (NWs) grown on InP substrates which operate in longer wavelengths. InP NWs comprising single or multiple (20) InAs/InAsP QDics axially embedded in an n-i-n geometry, have been grown on InP substrates using metal organic vapor phase epitaxy (MOVPE). The NWs are contacted in vertical direction by atomic layer deposition (ALD) deposition of 50 nm SiO2 as an insulating layer followed by sputtering of indium tin oxide (ITO) and evaporation of Ti and Au as top contact layer. In order to extend the sensitivity range to the mid-wavelength and long-wavelength regions, the intersubband transition within conduction band of InAsP QDisc is suggested. We present first experimental indications of intersubband photocurrent in NW geometry and discuss important design parameters for realization of intersubband detectors. Key advantages with the proposed design include large degree of freedom in choice of materials compositions, possible enhanced optical resonance effects due to periodically ordered NW arrays and the compatibility with silicon substrates. We believe that the proposed detector design offers the route towards monolithic integration of compact and sensitive III-V NW long wavelength detectors with Si technology.

Keywords: intersubband photodetector, infrared, nanowire, quantum disc

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Authors: M. Abbasi Layegh, S. Haghipour, K. Athari, R. Khosravi, M. Tafkikialamdari

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An approach to find the optimum mel-frequency cepstral coefficients (MFCCs) for the Radif of Mirzâ Ábdollâh, which is the principal emblem and the heart of Persian music, performed by most famous Iranian masters on two Iranian stringed instruments ‘Tar’ and ‘Setar’ is proposed. While investigating the variance of MFCC for each record in themusic database of 1500 gushe of the repertoire belonging to 12 modal systems (dastgâh and âvâz), we have applied the Fuzzy C-Mean clustering algorithm on each of the 12 coefficient and different combinations of those coefficients. We have applied the same experiment while increasing the number of coefficients but the clustering accuracy remained the same. Therefore, we can conclude that the first 7 MFCCs (V-7MFCC) are enough for classification of The Radif of Mirzâ Ábdollâh. Classical machine learning algorithms such as MLP neural networks, K-Nearest Neighbors (KNN), Gaussian Mixture Model (GMM), Hidden Markov Model (HMM) and Support Vector Machine (SVM) have been employed. Finally, it can be realized that SVM shows a better performance in this study.

Keywords: radif of Mirzâ Ábdollâh, Gushe, mel frequency cepstral coefficients, fuzzy c-mean clustering algorithm, k-nearest neighbors (KNN), gaussian mixture model (GMM), hidden markov model (HMM), support vector machine (SVM)

Procedia PDF Downloads 446

Authors: Emmanuel Chinagorom Nwadike, Joseph Tagbo Nwabanne, Matthew Ndubuisi Abonyi, Onyemazu Andrew Azaka

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This research focused on the modeling of the convective drying of aerial yam using finite element methods. The thermo-gravimetric analyzer was used to determine the thermal stability of the sample. An aerial yam sample of size 30 x 20 x 4 mm was cut with a mold designed for the purpose and dried in a convective dryer set at 4m/s fan speed and temperatures of 68.58 and 60.56°C. The volume shrinkage of the resultant dried sample was determined by immersing the sample in a toluene solution. The finite element analysis was done with PDE tools in Matlab 2015. Seven kinetic models were employed to model the drying process. The result obtained revealed three regions in the thermogravimetric analysis (TGA) profile of aerial yam. The maximum thermal degradation rates of the sample occurred at 432.7°C. The effective thermal diffusivity of the sample increased as the temperature increased from 60.56°C to 68.58°C. The finite element prediction of moisture content of aerial yam at an air temperature of 68.58°C and 60.56°C shows R² of 0.9663 and 0.9155, respectively. There was a good agreement between the finite element predicted moisture content and the measured moisture content, which is indicative of a highly reliable finite element model developed. The result also shows that the best kinetic model for the aerial yam under the given drying conditions was the Logarithmic model with a correlation coefficient of 0.9991.

Keywords: aerial yam, finite element, convective, effective, diffusivity

Procedia PDF Downloads 153

Authors: Mohammad Hadi Mahmoodi, Azam Ghonchepoor, Sheilan Sohrabi

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The present study was conducted to investigate the effect of foreign language classroom anxiety and ambiguity tolerance on EFL Learners’ listening proficiency. In so doing, 442 EFL learners were randomly selected form Azad University and some accredited language institutions in Hamaden, and were given the Foreign Language Classroom Anxiety Scale (FLCAS) (1983), and Second Language Tolerance of Ambiguity Scale (SLTAS) (1995). Participants’ listening proficiency level was determined through listening scores gained in standardized exams given by university professors or institutes in which they studied English. The results of two-way ANOVA revealed that listening proficiency was significantly affected by the interaction of anxiety and AT level of the participants. Each of the two variables were categorized in three levels of High, Mid, and Low. The highest mean score of listening belonged to the group with low degree of anxiety and high degree of ambiguity tolerance, and the lowest listening mean score was gained by the group with high level of anxiety and low level of tolerance of ambiguity. Also, the findings of multiple regressions confirmed that anxiety was the stronger predictor of listening comprehension in contrast with tolerance of ambiguity. Furthermore, the result of Pearson correlation coefficient showed that there was a significant negative relationship between the participants’ foreign language classroom anxiety and their ambiguity tolerance level.

Keywords: Foreign Language Classroom Anxiety, Second language tolerance of ambiguity, Listening proficiency

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Authors: Ehsan B. Haghighi, Pavel Makhnatch, Jörgen Rogstam

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The ice rink floor is the largest heat exchanger in an ice rink. The important part of the floor consists of concrete, and the thermophysical properties of this concrete have strong influence on the energy usage of the ice rink. The thermal conductivity of concrete can be increased by using iron ore as ballast. In this study the Transient Plane Source (TPS) method showed an increase up to 58.2% of thermal conductivity comparing the improved concrete to standard concrete. Moreover, two alternative ice rink floor designs are suggested to incorporate the improved concrete. A 2D simulation was developed to investigate the temperature distribution in the conventional and the suggested designs. The results show that the suggested designs reduce the temperature difference between the ice surface and the brine by 1-4 ˚C, when comparing with convectional designs at equal heat flux. This primarily leads to an increased coefficient of performance (COP) in the primary refrigeration cycle and secondly to a decrease in the secondary refrigerant pumping power. The suggested designs have great potential to reduce the energy usage of ice rinks. Depending on the load scenario in the ice rink, the saving potential lies in the range of 3-10% of the refrigeration system energy usage. This calculation is based on steady state conditions and the potential with improved dynamic behavior is expected to increase the potential saving.

Keywords: Concrete, iron ore, ice rink, energy saving

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Authors: Tanwarat Kajsongkram, Saowalux Rotamporn, Sirinat Limbunruang, Sirinan Thubthimthed.

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High-Performance Liquid Chromatography (HPLC) method was developed and validated for simultaneous estimation of 6-Gingerol(6G) and 6-Shogaol(6S) in joint pain relief gel containing ginger extract. The chromatographic separation was achieved by using C18 column, 150 x 4.6mm i.d., 5μ Luna, mobile phase containing acetonitrile and water (gradient elution). The flow rate was 1.0 ml/min and the absorbance was monitored at 282 nm. The proposed method was validated in terms of the analytical parameters such as specificity, accuracy, precision, linearity, range, limit of detection (LOD), limit of quantification (LOQ), and determined based on the International Conference on Harmonization (ICH) guidelines. The linearity ranges of 6G and 6S were obtained over 20-60 and 6-18 µg/ml respectively. Good linearity was observed over the above-mentioned range with linear regression equation Y= 11016x- 23778 for 6G and Y = 19276x-19604 for 6S (x is concentration of analytes in μg/ml and Y is peak area). The value of correlation coefficient was found to be 0.9994 for both markers. The limit of detection (LOD) and limit of quantification (LOQ) for 6G were 0.8567 and 2.8555 µg/ml and for 6S were 0.3672 and 1.2238 µg/ml respectively. The recovery range for 6G and 6S were found to be 91.57 to 102.36 % and 84.73 to 92.85 % for all three spiked levels. The RSD values from repeated extractions for 6G and 6S were 3.43 and 3.09% respectively. The validation of developed method on precision, accuracy, specificity, linearity, and range were also performed with well-accepted results.

Keywords: ginger, 6-gingerol, HPLC, 6-shogaol

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Authors: Dalhatu, Musa Yusha’u, Shuaibu Sidi Safiyanu, Haliru Musa Hussaini

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This study examined budget and performance of public enterprises in Nasarawa State, Nigeria in a period of 2009-2013. The study utilized secondary sources of data obtained from four selected parastatals’ budget allocation and revenue generation for the period under review. The simple correlation coefficient was used to analyze the extent of the relationship between budget allocation and revenue generation of the parastatals. Findings revealed varying results. There was positive (0.21) and weak correlation between expenditure and revenue of Nasarawa Investment and Property Development Company (NIPDC). However, the study further revealed that there was strong and weak negative relationship in the revenue and expenditure of the following parastatals over the period under review. Viz: Nasarawa State Water Board, -0.27 (weak), Nasarawa State Broadcasting Service, -0.52 (Strong) and Nasarawa State College of Agriculture, -0.36 (weak). The study therefore, recommends that government should increase its investments in NIPDC to enhance efficiency and profitability. It also recommends that government should strengthen its fiscal responsibility, accountability and transparency in public parastatals.

Keywords: budget, public enterprises, revenue, enterprise

Procedia PDF Downloads 259

Authors: Ivanova B. Natalia, Djambova Т. Svetlana, Hristev S. Ivailo

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The acoustic properties of recycled felt panels have been investigated using various methods. Experimentally, the sound insulation of the panels has been evaluated for frequencies in the range of 600 Hz to 4000 Hz, utilizing a small-sized acoustic chamber. Additionally, the sound absorption coefficient for the frequency range of 63 Hz to 4000 Hz was measured according to the EN ISO 354 standard in a laboratory reverberation room. This research was deemed necessary after conducting reverberation time measurements of a university classroom following the EN ISO 3382-2 standard. The measurements indicated values of 2.86 s at 500 Hz, 3.23 s at 1000 Hz, and 2.53 s at 2000 Hz, which significantly exceeded the requirements set by the national regulatory framework (0.6s) for such premises. For this reason, recycled felt panels have been investigated in the laboratory, showing very good acoustic properties at high frequencies. To enhance performance in the low frequencies, the influence of the distance of the panel spacing was examined. Furthermore, the sound insulation of the panels was studied to expand the possibilities of their application, both for the acoustic treatment of educational and multifunctional halls and for sound insulation purposes (e.g., a suspended ceiling with an air gap passing from room to room). As a conclusion, a theoretical acoustic design of the classroom has been carried out with suggestions for improvements to achieve the necessary acoustic and aesthetic parameters for such rooms.

Keywords: acoustic panels, recycled felt, sound absorption, sound insulation, classroom acoustics

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Authors: Changyeop Lee, Sewon Kim, Jongho Lee

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Reburning technology has been developed to adopt various commercial combustion systems. Fuel lean reburning is an advanced reburning method to reduce NOx economically without using burnout air, however it is not easy to get high NOx reduction efficiency. In the fuel lean reburning system, the localized fuel rich eddies are used to establish partial fuel rich regions so that the NOx can react with hydrocarbon radical restrictively. In this paper, a new advanced reburning method which supplies reburn fuel with oscillatory motion is introduced to increase NOx reduction rate effectively. To clarify whether forced oscillating injection of reburn fuel can effectively reduce NOx emission, experimental tests were conducted in vertical combustion furnace. Experiments were performed in flames stabilized by a gas burner, which was mounted at the bottom of the furnace. The natural gas is used as both main and reburn fuel and total thermal input is about 40kW. The forced oscillating injection of reburn fuel is realized by electronic solenoid valve, so that fuel rich region and fuel lean region is established alternately. In the fuel rich region, NOx is converted to N2 by reburning reaction, however unburned hydrocarbon and CO is oxidized in fuel lean zone and mixing zone at downstream where slightly fuel lean region is formed by mixing of two regions. This paper reports data on flue gas emissions and temperature distribution in the furnace for a wide range of experimental conditions. All experimental data has been measured at steady state. The NOx reduction rate increases up to 41% by forced oscillating reburn motion. The CO emissions were shown to be kept at very low level. And this paper makes clear that in order to decrease NOx concentration in the exhaust when oscillating reburn fuel injection system is adopted, the control of factors such as frequency and duty ratio is very important.

Keywords: NOx, CO, reburning, pollutant

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Authors: M. Moody, R. Mahmoodi, A. R. Zolfaghari, A. Aminottojari

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In this study, flow inside the shell side of a shell-and-tube heat exchanger is simulated numerically for laminar and turbulent flows in both steady state and transient mode. Governing equations of fluid flow are discrete using finite volume method and central difference scheme and solved with simple algorithm which is staggered grid by using MATLAB programming language. The heat transfer coefficient is obtained using velocity field from equation Dittus-Bolter. In comparison with, heat exchanger is simulated with ANSYS CFX software and experimental data measured in the THTL test loop. Numerical results obtained from the study show good agreement with experimental data and ANSYS CFX results. In addition, by deliberation the effect of the baffle spacing and the baffle cut on the heat transfer rate for turbulent flow, it is illustrated that the heat transfer rate depends on the baffle spacing and the baffle cut directly. In other word in spied of large turbulence, if these two parameters are not selected properly in the heat exchanger, the heat transfer rate can reduce.

Keywords: shell-and-tube heat exchanger, flow and heat transfer, laminar and turbulence flow, turbulence model, baffle spacing, baffle cut

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Authors: H. Higashiyama, M. Sappakittipakorn, M. Mizukoshi, O. Takahashi

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Ceramic waste aggregates (CWAs) were made from electric porcelain insulator wastes supplied from an electric power company, which were crushed and ground to fine aggregate sizes. In this study, to develop the CWA mortar as an eco–efficient, ground granulated blast–furnace slag (GGBS) as a supplementary cementitious material (SCM) was incorporated. The water–to–binder ratio (W/B) of the CWA mortars was varied at 0.4, 0.5, and 0.6. The cement of the CWA mortar was replaced by GGBS at 20 and 40% by volume (at about 18 and 37% by weight). Mechanical properties of compressive and splitting tensile strengths, and elastic modulus were evaluated at the age of 7, 28, and 91 days. Moreover, the chloride ingress test was carried out on the CWA mortars in a 5.0% NaCl solution for 48 weeks. The chloride diffusion was assessed by using an electron probe microanalysis (EPMA). To consider the relation of the apparent chloride diffusion coefficient and the pore size, the pore size distribution test was also performed using a mercury intrusion porosimetry at the same time with the EPMA. The compressive strength of the CWA mortars with the GGBS was higher than that without the GGBS at the age of 28 and 91 days. The resistance to the chloride ingress of the CWA mortar was effective in proportion to the GGBS replacement level.

Keywords: ceramic waste aggregate, chloride diffusion, GGBS, pore size distribution

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Authors: Ziyad Abunada, Abir Al-tabbaa

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The current work is investigating the effectiveness of combined mixed materials mainly modified bentonites and organoclay in treating contaminated groundwater. Sodium bentonite was manufactured with a quaternary amine surfactant, dimethyl ammonium chloride to produce organoclay (OC). Inorgano-organo bentonite (IOB) was produced by intercalating alkylbenzyd-methyl-ammonium chloride surfactant into sodium bentonite and pillared with chlorohydrol pillaring agent. The materials efficiency was tested for both TEX compounds from model-contaminated water and a mixture of organic contaminants found in groundwater samples collected from a contaminated site in the United Kingdom. The sorption data was fitted well to both Langmuir and Freundlich adsorption models reflecting the double sorption model where the correlation coefficient was greater than 0.89 for all materials. The mixed materials showed higher sorptive capacity than individual material with a preference order of X> E> T and a maximum sorptive capacity of 21.8 mg/g was reported for IOB-OC materials for o-xylene. The mixed materials showed at least two times higher affinity towards a mixture of organic contaminants in groundwater samples. Other experimental parameters such as pH and contact time were also investigated. The pseudo-second-order rate equation was able to provide the best description of adsorption kinetics.

Keywords: modified bentobite, groundwater, adsorption, contaminats

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Authors: T. Sakamoto, S. Kainuma

Abstract:

Firstly, in order to examine the influence of the remaining amount of the rust on the coating film durability, the accelerated deterioration tests were carried out. In order to prepare test specimens, uncoated steel plates were corroded by the Salt Spray Test (SST) prior to the accelerated deterioration tests, and then the prepared test specimens were coated by epoxy resin and phthalic acid resin each of which has different gas-barrier performance. As the result, it was confirmed that the under-film corrosion occurred in the area and the adjacency to great quantities of salt exists in the rust, and did not occurred in the specimen which was applied the epoxy resin paint after the surface preparation by the power tool. Secondly, in order to clarify the influence of the corrosive factors on the coating film durability, outdoor exposure tests were conducted for one year on actual steel bridge located at a coastal area. The tests specimens consist of coated corroded plates and the uncoated steel plates, and they were installed on the different structural members of the bridge for one year. From the test results, the uncoated steel plates which were installed on the underside of the member are easily corrosive and had highly correlation with the amount of salt in the rust. On the other hand, the most corrosive under-film steel was the vertical surface of the web plate. Thus, it was confirmed that under-film corrosion rate was not match with corrosion rate of the uncoated steel. Consequently, it is estimated that the main factors of under-film corrosion are gas-barrier property of coating film and corrosive factors such as water vapor and temperature. The salt which significantly corrodes the uncoated steel plate is not directly related to the under-film corrosion.

Keywords: accelerated deterioration test, coating durability, environmental factor, under-film corrosion

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Authors: S. M. Dash, K. B. Lua, T. T. Lim

Abstract:

This paper presents results of numerical and experimental studies on a two-dimensional (2D) flapping elliptic airfoil in a forward flight condition at Reynolds number of 5000. The study is motivated from an earlier investigation which shows that the deterioration in thrust performance of a sinusoidal heaving and pitching 2D (NACA0012) airfoil at high flapping frequency can be recovered by changing the effective angle of attack profile to square wave, sawtooth, or cosine wave shape. To better understand why such modifications lead to superior thrust performance, we take a closer look at the transient aerodynamic force behavior of an airfoil when the effective angle of attack profile changes gradually from a generic smooth trapezoidal profile to a sinusoid shape by modifying the base length of the trapezoid. The choice of using a smooth trapezoidal profile is to avoid the infinite acceleration condition encountered in the square wave profile. Our results show that the enhancement in the time-averaged thrust performance at high flapping frequency can be attributed to the delay and reduction in the drag producing valley region in the transient thrust force coefficient when the effective angle of attack profile changes from sinusoidal to trapezoidal.

Keywords: two-dimensional flapping airfoil, thrust performance, effective angle of attack, CFD, experiments

Procedia PDF Downloads 358

Authors: Agoston Restas

Abstract:

Introduction: This paper describes many initiatives and shows also practical examples which happened recently using Unmanned Aerial Systems (UAS) to support disaster management. Since the operation of manned aircraft at disasters is usually not only expensive but often impossible to use as well, in many cases managers fail to use the aerial activity. UAS can be an alternative moreover cost-effective solution for supporting disaster management. Methods: This article uses thematic division of UAS applications; it is based on two key elements, one of them is the time flow of managing disasters, other is its tactical requirements. Logically UAS can be used like pre-disaster activity, activity immediately after the occurrence of a disaster and the activity after the primary disaster elimination. Paper faces different disasters, like dangerous material releases, floods, earthquakes, forest fires and human-induced disasters. Research used function analysis, practical experiments, mathematical formulas, economic analysis and also expert estimation. Author gathered international examples and used own experiences in this field as well. Results and discussion: An earthquake is a rapid escalating disaster, where, many times, there is no other way for a rapid damage assessment than aerial reconnaissance. For special rescue teams, the UAS application can help much in a rapid location selection, where enough place remained to survive for victims. Floods are typical for a slow onset disaster. In contrast, managing floods is a very complex and difficult task. It requires continuous monitoring of dykes, flooded and threatened areas. UAS can help managers largely keeping an area under observation. Forest fires are disasters, where the tactical application of UAS is already well developed. It can be used for fire detection, intervention monitoring and also for post-fire monitoring. In case of nuclear accident or hazardous material leakage, UAS is also a very effective or can be the only one tool for supporting disaster management. Paper shows some efforts using UAS to avoid human-induced disasters in low-income countries as part of health cooperation.

Keywords: disaster management, floods, forest fires, Unmanned Aerial Systems

Procedia PDF Downloads 237

Authors: Haj Najafi Leila, Tehranizadeh Mohsen

Abstract:

Dependencies between diverse factors involved in probabilistic seismic loss evaluation are recognized to be an imperative issue in acquiring accurate loss estimates. Dependencies among component damage costs could be taken into account considering two partial distinct states of independent or perfectly-dependent for component damage states; however, in our best knowledge, there is no available procedure to take account of loss dependencies in story level. This paper attempts to present a method called "modal cost superposition method" for decoupling story damage costs subjected to earthquake ground motions dealt with closed form differential equations between damage cost and engineering demand parameters which should be solved in complex system considering all stories' cost equations by the means of the introduced "substituted matrixes of mass and stiffness". Costs are treated as probabilistic variables with definite statistic factors of median and standard deviation amounts and a presumed probability distribution. To supplement the proposed procedure and also to display straightforwardness of its application, one benchmark study has been conducted. Acceptable compatibility has been proven for the estimated damage costs evaluated by the new proposed modal and also frequently used stochastic approaches for entire building; however, in story level, insufficiency of employing modification factor for incorporating occurrence probability dependencies between stories has been revealed due to discrepant amounts of dependency between damage costs of different stories. Also, more dependency contribution in occurrence probability of loss could be concluded regarding more compatibility of loss results in higher stories than the lower ones, whereas reduction in incorporation portion of cost modes provides acceptable level of accuracy and gets away from time consuming calculations including some limited number of cost modes in high mode situation.

Keywords: dependency, story-cost, cost modes, engineering demand parameter

Procedia PDF Downloads 180

Authors: Li Guoyou, Zhang Tao, Ji Wenzhan, Huo Liang, Lin Xiqiang, Zhang Nan

Abstract:

The three dimensional (3D) printing technology has undergone rapid development in the last few years and it is possible to print engineering structures. 3D printing buildings use wastes from constructions, industries and mine tailings as “ink”, and mix it with property improved materials, such as cement, fiber etc. This paper presents a study of the Thermodynamic performance of 3D printed walls using cement and steel slag powder. Analyses the thermal simulation regarding 3D printed walls and solid brick wall by the way of the hot-box methods and the infrared technology, and the results were contrasted with theoretical calculation. The results show that the excellent thermodynamic performance of 3D printed concrete wall made it suitable as the partial materials for self-thermal insulation walls in residential buildings. The thermodynamic performance of 3D printed concrete walls depended on the density of materials, distribution of holes, and the filling materials. Decreasing the density of materials, increasing the number of holes or replacing the filling materials with foamed concrete could improve its thermodynamic performance significantly. The average of heat transfer coefficient and thermal inertia index of 3D printed steel slag powder concrete wall all better than the traditional solid brick wall with a thickness of 240mm.

Keywords: concrete, 3D printed walls, thermodynamic performance, steel slag powder

Procedia PDF Downloads 183

Authors: F. Rashno Seydari, M. Nikafrooz

Abstract:

This paper intends to study needs analysis of hearing-impaired students’ teachers in elementary schools all over Iran. The subjects of this study were 275 teachers who were teaching hearing-impaired students in elementary schools. The participants were selected by a quota sampling method. To collect the data, questionnaires of training needs consisting of 41 knowledge items and 31 performance items were used. The collected data were analyzed by using SPSS software in the form of descriptive analyses (frequency and mean) and inferential analyses (one sample t-test, paired t-test, independent t-test, and Pearson correlation coefficient). The findings of the study indicated that teachers generally have considerable needs in knowledge and performance domains. In 32 items out of the total 41 knowledge domain items and in the 27 items out of the total 31 performance domain items, the teachers had considerable needs. From the quantitative point of view, the needs of the performance domain were more than those of the knowledge domain, so they have to be considered as the first priority in training these teachers. There was no difference between the level of the needs of male and female teachers. There was a significant difference between the knowledge and performance domain needs and the teachers’ teaching experience, 0.354 and 0.322 respectively. The teachers who had been trained in working with hearing-impaired students expressed more training needs (both knowledge and performance).

Keywords: educational needs analysis, teachers of hearing impaired students, knowledge domain, function domain

Procedia PDF Downloads 96

Authors: Irnie Zakaria, W. A. N. W. Mohamed, W. H. Azmi

Abstract:

Thermal enhancement of a single mini channel in Proton Exchange Membrane Fuel Cell (PEMFC) cooling plate is numerically investigated. In this study, low concentration of Al2O3 in Water - Ethylene Glycol mixtures is used as coolant in mini channel of carbon graphite plate to mimic the PEMFC cooling plate. A steady and incompressible flow with constant heat flux is assumed in the channel of 1mm x 5mm x 100mm. Nano particle of Al2O3 used ranges from 0.1, 0.3 and 0.5 vol % concentration and then dispersed in 60:40 (water: Ethylene Glycol) mixture. The effect of different flow rates to fluid flow and heat transfer enhancement in Re number range of 20 to 140 was observed. The result showed that heat transfer coefficient was improved by 18.11%, 9.86% and 5.37% for 0.5, 0.3 and 0.1 vol % Al2O3 in 60:40 (water: EG) as compared to base fluid of 60:40 (water: EG). It is also showed that the higher vol % concentration of Al2O3 performed better in term of thermal enhancement but at the expense of higher pumping power required due to increase in pressure drop experienced. Maximum additional pumping power of 0.0012W was required for 0.5 vol % Al2O3 in 60:40 (water: EG) at Re number 140.

Keywords: heat transfer, mini channel, nanofluid, PEMFC

Procedia PDF Downloads 339

Authors: Bharat Kumar, Deepak Kumar, Vijay Chaudhry

Abstract:

Zirconium alloys exhibit low neutron absorption cross-section and excellent mechanical properties. Due to these unique characteristics, these materials are widely used in designing core components of pressurized heavy water reactors (PHWRs). Another material that is widely used in the design of reactor core is stainless steel. Under operating conditions of the reactor, there are possibilities for mechanical and tribological interaction between the components made of zirconium alloy (Zr-2.5 Nb) and stainless steel (SS-410). This may result in wear of the material. To study the tribological characteristics of Zr-2.5 Nb and SS-410, low amplitude reciprocating wear tests are conducted at room temperature and at high temperatures (260 degrees Celsius). The tests are conducted at frequencies ranging from 5 Hz to 25 Hz. The displacement amplitude is varied from 200 µm to 600 µm. The responses are recorded, analyzed and correlated with damage observed using scanning electron microscopy (SEM) and an optical profilometer. Energy dispersive spectroscopy (EDS) is used to study the damage mechanism prevailing at the contact interface. A higher coefficient of friction (COF) is observed at higher temperatures as compared to the one at room temperature. Tests carried out at high temperature reveals adhesive wear as the dominant mechanism resulting in significant material transfer.

Keywords: PHWRs, Zr-2.5Nb, SS-410, wear

Procedia PDF Downloads 92