Al-Abbas A.H.,Foundation of Technical Education |
Naser J.,Swinburne University of Technology |
Hussein E.K.,Foundation of Technical Education
Fuel | Year: 2013
In the present paper, a computational fluid dynamics (CFD) modeling study was performed for the combustion of the brown coal in a large-scale tangentially-fired furnace (550 MW) under different operating conditions. The AVL Fire CFD code has been used to model the combustion processes. The mathematical models of coal combustion with the appropriate kinetic parameters were written and incorporated to the code as user defined functions. These models consist of pulverised coal (PC) devolatilization, char burnout, and heat and mass transfer. The simulation of the PC combustion was carried out using multi-step reaction chemistry mechanisms. The level of confidence of this numerical model was based on the previous validations of the lignite combustion in a lab-scale furnace, as well as the validation parameters of the present furnace at the standard existing conditions in terms of temperature values and species concentrations. Performance of the boiler under ten different operating conditions was investigated. The strategy of operation schemes for the first six combustion scenarios were based on the change of the out-of-service (turned off) burners under full load operation, while the rest cases were carried out at 20% lower and 20% higher loads than the standard operating conditions. The validated model was used to perform the following investigation parameters: furnace gas temperatures, species concentrations (O2, CO and CO 2), velocity distributions, and char consumption. The predictions demonstrated that there are good temperature distributions in the furnace when the turned off burners are set in the opposite direction under full load operation. For higher aerodynamic effect, the numerical results showed improvements on the combustion characteristics in terms of species concentrations and char burnout rates in comparison with the standard operating case. The findings of this study provide good information to optimize the operations of the utility tangentially coal-fired boiler with less emission. © 2012 Elsevier Ltd. All rights reserved.
Babakir-Mina M.,University of Rome Tor Vergata |
Babakir-Mina M.,Foundation of Technical Education |
Ciccozzi M.,National Institute of Health |
Perno C.F.,University of Rome Tor Vergata |
Ciotti M.,University of Rome Tor Vergata
APMIS | Year: 2013
In 2007, two novel polyomaviruses KI and WU were uncovered in the respiratory secretions of children with acute respiratory symptoms. Seroepidemiological studies showed that infection by these viruses is widespread in the human population. Following these findings, different biological specimens and body compartments have been screened by real-time PCR in the attempt to establish a pathogenetic role for KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) in human diseases. Although both viruses have been found mainly in respiratory tract samples of immunocompromised patients, a clear causative link with the respiratory disease has not been established. Indeed, the lack of specific clinical or radiological findings, the frequent co-detection with other respiratory pathogens, the detection in subjects without signs or symptoms of respiratory disease, and the variability of the viral loads measured did not allow drawing a definitive conclusion. Prospective studies carried out on a large sample size including both immunocompromised and immunocompetent patients with and without respiratory symptoms are needed. Standardized quantitative real-time PCR methods, definition of a clear clinical cutoff value, timing in the collection of respiratory samples, are also crucial to understand the pathogenic role, if any, of KIPyV and WUPyV in human pathology. © 2013 APMIS.
Yaseen A.A.,Foundation of Technical Education
2012 2nd International Conference on Advances in Computational Tools for Engineering Applications, ACTEA 2012 | Year: 2012
Power factor measuring is an important issue in industrial environment to maintain an acceptable quality of the delivered power. This paper describes a novel and fast response power factor computation technique. It employs microcontroller and two phase-locked loop (PLL) circuits. Only one sample from two signals that formed from the source voltage and the load current are required to execute the power factor computation using microcontroller. The system gives the instantaneous power factor reading during the PLL steady state conditions. The experimentally results of the proposed system has been found to be satisfactory. © 2012 IEEE.
Al-Shamani A.N.,National University of Malaysia |
Al-Shamani A.N.,Foundation of Technical Education |
Yazdi M.H.,National University of Malaysia |
Alghoul M.A.,National University of Malaysia |
And 4 more authors.
Renewable and Sustainable Energy Reviews | Year: 2014
The use of nanofluids for cooling is an attracting considerable attention in various industrial applications. Compared with conventional fluids, nanofluids improve the heat transfer rate, as well as the optical properties, thermal properties, efficiency, and transmission and extinction coefficients of solar systems. The effects of different nanofluids on the cooling rate and hence the efficiency of solar systems can be experimentally investigated. Accordingly, this review paper presents the effects of nanofluids on the performance of solar collectors from the considerations of efficiency and environmental benefits. A review of literature shows that many studies have evaluated the potential of nanofluids for cooling different thermal systems. The second part of this paper presents an overview of the research, performance, and development of photovoltaic/thermal (PV/T) collector systems. Descriptions are made on water PV/T collector types, analytical and numerical models, and simulation and experimental works. The parameters affecting PV/T performance such as covered versus uncovered PV/T collectors, absorber plate parameters, and absorber configuration design types are extensively discussed. Exergy analysis shows that the coverless PV/T collector produces the largest total (electrical+thermal) exergy. Furthermore, PV/T collectors are observed to be very promising devices, and further work should be carried out to improve their efficiency and reduce their cost. Therefore, using nanofluids for cooling PV/T systems may be reasonable. © 2014 Elsevier Ltd.
Fayadh R.A.,Foundation of Technical Education
Advanced Materials Research | Year: 2012
D.C motors have special important uses for human that used in many places needs a specific speed or variable speed, so that we need to control this speed for any purpose. Nowadays, the subject of controlling the electric motor and measuring variable is of important subject. Because of scientific and technical development in this field according to difficulty of teaching control material by using computer. In the traditional way the past studies assumed that the best method to understand the concepts of controlling by the computer are by practical exercises in lab and since the lab doesn't contain such ability. This search was represented to do the first step in teaching general principals of controlling by design a window dealing with computer to control the speed of d.c motor. The work on the program helps to use more than one sense which helps to stable the scientific material in the mind of students . © (2012) Trans Tech Publications, Switzerland.
Hamed H.H.,Foundation of Technical Education
International Journal of Applied Engineering Research | Year: 2014
Two - Tubes columns pressure swing adsorption (PSA) unit, (6cm diameter and 70cm bed length) and a dryer part(12cm diameter and 27cm) filling with activated alumina(Al2O3) have been constructed to study the separation of oxygen from air using commercial 5A zeolite under the effect of adsorption pressure (1 to 6 bar), adsorption time(20s), product flow rate (1 liter/min) on the product oxygen purity. For the case of2-column, 4-step operation, the results show that an optimum concentration product of oxygen was 76. 9%purity, at the adsorption pressure 4bar, Temp 17. 4°C, total operation time 46 min(30min to reach steady state and starting Production). © Research India Publications.
Salih M.A.,University Putra Malaysia |
Salih M.A.,Foundation of Technical Education |
Abang Ali A.A.,University Putra Malaysia |
Farzadnia N.,University Putra Malaysia
Construction and Building Materials | Year: 2014
This study delineates activation of palm oil fuel ash (POFA) by a combination of sodium silicate and sodium hydroxide at 60 °C to be used as a geopolymer binder. Qualitative observations as well as compressive strength were recorded to assess the viability of POFA utilization. Also, XRD, SEM/EDX, DSC, FTIR tests were conducted to investigate underlying mechanisms of geopolymerization. The post-test observations revealed that activation of POFA is applicable and compressive strength of up to 32.48 MPa at the age of 28 days was achieved. Chemical tests indicated that formation of calcium silicate hydrate was the dominant cause of geopolymerization. © 2014 Elsevier Ltd. All rights reserved.
Yaseen A.A.,Foundation of Technical Education
Advanced Materials Research | Year: 2012
The trend in industrial control has been to reduce the communications wiring across a plant. Eliminating the cabled connection between a sensors and a host computer enhances the performances and the manageability of a data acquisition system. Through the use of Bluetooth technology the data acquisition components can be paired with a wide variety of pre-existing devices. This makes the host computer portable, cheaper and versatile. Data is collected from the sensors by a microcontroller with an attached Bluetooth module, which transmits the data to a host computer for processing. Costs are reduced by making use of pre-existing processing power and display on the host computer. Depending on the application the data can be processed in any way required on the host computer. This paper describes the practical design of Bluetooth based 12-Channel temperatures acquisition system which contains remote temperature sensors connected to a microcontroller which controls also the Bluetooth module transmission, and a computer connected to a Bluetooth adapter. In this way, the sensors data are collected and processed by the microcontroller, transmitted via Bluetooth to a host computer which monitoring and recording the temperatures measurements. © (2012) Trans Tech Publications, Switzerland.
Ali H.M.,Foundation of Technical Education |
Iqbal A.,Eastern Mediterranean University |
Hashemipour M.,Eastern Mediterranean University
Indian Journal of Engineering and Materials Sciences | Year: 2014
The dimensional accuracy and strength of a part is of critical importance in the manufacturing industry, especially for precision assembly operation. In the manufacturing process, the designed part will be presented in a drawing with all dimensions normally given within a certain range of tolerances. The tolerance defines the limits of induced deviation for which allowance should be made in the design, and within which actual size is acceptable. In laser and abrasive water jet cutting, dimensional accuracy is one of the important parameters to define the quality of produced part. The aim of the present work is to compare experimentally the influence of cutting parameters on dimensional accuracy and strength of hole making in GFRP by using laser beam and abrasive water jet cutting technologies. Full factorial design is used as a statistical method to study the effects of predictor variables on the response variables. The results show that abrasive water jet cutting gives a less out of roundness in cutting hole diameter, less reduction in strength and large difference between upper and lower diameter compared to the laser cutting technology of hole making in the type of the glass fiber reinforced plastic composite material used in the present work.
Bdnoiu A.I.,Polytechnic University of Bucharest |
Abood Al-Saadi T.H.,Polytechnic University of Bucharest |
Abood Al-Saadi T.H.,Foundation of Technical Education |
Voicu G.,Polytechnic University of Bucharest
International Journal of Mineral Processing | Year: 2015
This study presents data regarding the synthesis of binding materials through the alkaline activation of waste glass (bottle glass cullet) with NaOH solution. As addition was used red mud, a residue resulted in bauxite processing, due to its high alkalinity and aluminum content. This paper presents the influence of processing parameters (composition of solid component, curing time and temperature) on the compressive strength and hydrolytic stability of this type of alkali activated cements. The effect of red mud addition on the hardening processes, reaction products and material's microstructure was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (TG & DTA). The main reaction products are sodium silicate or/and sodium silicate aluminates hydrates with amorphous to crystalline morphologies. The amount of reaction products increases with the increase of the initial curing time at 60°C and consequently it was achieved an increase of the compressive strength values. As a negative side effect the hydrolytic stability of these materials is affected by the increase of the initial curing time at 60°C. Despite the fact that addition of aluminum to sodium silicate hydrates improve their hydrolytic stability, the expected positive influence of red mud addition to the studied binding systems was not observed. This can be due to the low amount of supplementary aluminum brought in the activator solution by the red mud as well as the high amount of iron phases present also in this waste. © 2014 Elsevier B.V. All rights reserved.