a INSTITUTE OF ENVIRONMENTAL ENGINEERING,
NATIONAL CHIAO TUNG UNIVERSITY , HSIN CHU, TAIWAN Published online: 13 Jun 2007.
To cite this article: Hsin-Chung Lu & Chuen-Jinn Tsai (1998) APilot-ScaleStudyoftheDesignandOperationParametersofaPulse-JetBaghouse, Aerosol Science and Technology, 29:6, 510-524, DOI: 10.1080/02786829808965587
I NFLUENCE OF D ESIGN AND O PERATION P ARAMETERS ON
B AG -C LEANING P ERFORMANCE OF P ULSE -J ET B AGHOUSE
By Hsin-Chung Lu 1 and Chuen-Jinn Tsai 2
A BSTRACT : In this study, a filter test system with clean new fabric bags was used to measure thepulse pressure and acceleration ofthe filter bag. Fabric acceleration andpulse pressure were used as an index of bag-cleaning intensity. Thejet pump curves, which relate the flow rate through the venturi to the average developed pressure by the venturi, were determined by the similar system. The intersection ofthejet pump curve andthe bag operating line, which relates the pressure drop to flow rate across the bag during pulse-jet cleaning, is the system operating point that was used to predict the average pulse pressure in the bag during pulse-jet cleaning. Ex- perimental results of this study show that a higher pulse pressure can be achieved without the venturi at the top ofthe bag for bag materials with low resistance coefficient. For bags with higher resistance coefficients, higher pulse pressure is obtained with a venturi installed at the top ofthe bag. The predicted pressure values are in good agreement with experimental data. Dimensional analysis for jet pump performance was developed to reduce the experimental data. The results show that thejet pump curves obtained under different operating conditions can be reduced to the same nondimensional curve, which can be used to facilitate thedesignandoperationofapulse-jet cleaning system.
Influence of Different Cleaning Conditions on Cleaning Performance ofPilot-ScalePulse-JetBaghouse
Hsin-Chung Lu 1 and Chuen-Jinn Tsai 2
Abstract: In this study, apilot-scalepulse-jetbaghouse is utilized to control the particulate emission of an oil-fired boiler. The operating anddesignparameters, such as filtration velocity, initial tank pressure, and nozzle diameter, were varied to evaluate the cleaning effect ofthepulse-jetbaghouse. Two different cleaning types, 共1兲 high initial tank pressure and one bag cleaning; and 共2兲 low initial tank pressure and two consecutive bag cleanings, are used to compare the bag-cleaning performance in this study. It is found that the cleaning effect increases with the initial tank pressure. However, the cleaning intensity 共overpressure兲 does not increase with the nozzle diameter. There exists an optimum nozzle diameter to achieve higher cleaning intensity anda better cleaning effect. This phenomenon results from the small volume ofthebaghouse compartment in this study. If an industrial size baghouse was used, it suggests that a nozzle diameter larger than 13 mm and initial tank pressure greater than 2.5 kg/cm 2 should be adopted to achieve a higher cleaning effect. Between the two cleaning types, type 2 is found to be more effective to clean the bag andthe energy consumption for compressed air is reduced significantly from type 1. Therefore, type 2 bag cleaning is suggested to be a better method to clean thebaghouse.
In this studythe filtration velocity and filtration pressure drop at the beginning of bag cleaning were used as experimental parameters to evaluate the bag-cleaning per- formance ofapulse-jetbaghouse. The effective residual pressure loss was used to in- dicate the cleaning performance after bag cleaning. Two different test dusts, fly ash and limestone, were used. The critical cleaning indices under different operation conditions for bag cleaning were also investigated. A critical average pulse overpressure was found to exist beyond which bag-cleaning performance did not improve much. It was found the filter’s final filtration resistance is an important parameter to decide whether a Venturi is necessary for a good bag-cleaning performance or not. Use ofa Venturi was found to increase the average pulse overpressure for a system with a filter’s final resistance coefficient greater than about 500 Pa ⭈s/cm. However, no Venturi is recom- mended when the filter’s final resistance coefficient is smaller than 500 Pa ⭈s/cm.
300 ms, andthe maximum duration time is 450, 500, and 600 ms for P tk0 ) 2.0, 2.5, and 3.0 kg/cm 2 , respectively.
Effect of Distance between Nozzle and Bag Opening on Pressure Impulse. Figure 9 shows the effect of different distances between nozzle and bag opening on pressure impulse at point 7. The distances are 5, 10, 20, and 30 cm, respectively. Both experimental data and simulated results show that when the distance increases, the pressure impulse also increases. The increase in pressure impulse for ranging from 5 to 30 cm is about 10% for different initial tank pressures investigated. The experimental data of Rothwell (4) also show similar trend. Increase ofthe pressure impulse with the distance is because a longer distance between the nozzle and bag opening will allow more induced secondary air flow into the bag, which will result in an increase of pressure impulse in the bag. However, if the distance becomes too long, the spreading width ofthe nozzle exit flow at the bag opening may become greater than the bag diameter. Eventually only part ofthe nozzle and induced air flow will be pulsed into the bag, which may result in lower pressure impulse. That is, there is an optimum distance depending on nozzle and bag diameters. Opti- mization of this distance will be discussed in the next section.
Key Words: neural-network, orthogonal arrays, response surface methodology, PEMFC, operationparameters.
This paper presents a method for combining sequential neural-network approximation and orthogonal arrays (SNAOA) in determining the major operationanddesignparameters which affect the performance of proton exchange membrane fuel cells (PEMFC). An orthogonal array was first con- ducted to obtain the initial solution set. The results obtained from the or- thogonal array were then used as the experimental data for response surface methodology (RSM) that could predict theoperationparameters at discrete levels. The set was then treated as the initial training sample anda back- propagation sequential neural network was trained to simulate the feasible domain for seeking optimal operationparametersof PEMFC. With this method, the size ofthe training sample was greatly reduced due to the use ofthe orthogonal array. In addition, a restart strategy was also incorporated into the SNAOA so that the searching process could have a better opportunity to reach a near global optimum with the objective of reaching maximum output power ofthe PEMFC, which has a separate flow field in the cathode. The major parameters harnessed in this study include operating temperature, hu- midification temperature, reactant flow rate, split point, and split flow rate.
The highest scores ofthe isolation burden were those achieved by Scottish male caregivers while the Chinese male caregivers had the lowest scores.
Given the patterns of how care is provided this is not a surprising finding. Caring for patients inevitably limits the caregivers’ social activities. Caregivers will be less able to go anywhere that they might wish or to enjoy their holidays since they would have to make complicated or expensive arrangements to provide continuity of care. There is also the likelihood of their being worried about the patient when they are far away. Besides, they will be less able to invite their friends’ home during the period of caring for the patient. Therefore, this could also increase their sense of isolation as well as their emotional and general burden. The low Chinese scores are interesting because these caregivers are part ofa very close knit community in a foreign country. Therefore, they did not share feelings of isolation, however it might be noted that there were no Chinese sons in the sample and so some ofthe explanations for the sense of isolation experienced by the Scots would not hold true for the Chinese.
The potential gradient ranging from 2 to 5 V/cm were applied to induce the movement of bound water within the sludge specimen elapsed for 2 hr. Results showed that the direction of electroosmosis (EO) flow was from the anode to cathode. Due to the release of H + and OH - through electrolysis of water, the sludge pH was maintained at 5.9 ~ 6.8 near the anode side and 9.8 ~ 10.8 near the cathode after EK treatment. As applied potential gradient of 2~5 V/cm to EK system for 2 hr, the moisture content of sludge decreased further to 47.5 %. The EO permeability andthe power consumption throughout the test period are around 3.04 ~ 4.80 10 -5 cm 2 /V-s and 14.4 ~ 66.8 kWh/m 3 , respectively. Up to 20.8 ~ 27.9% of total disposal cost saving was found with aid of EK technique. It is concluded that the water can be effectively and economically removed from sludge by EK process.
Appendix AA Sample Article and Tasks in thePilotStudy
姓名 座號 Laugh Your Way to Health and Happiness
Do you ever feel depressed, tired, sick or just burned out? When you feel this way, maybe all that you need to feel better is a good dose of laughter. Laughing can instantly lift your spirits when you’re feeling down. But laughing does more than just make you feel better. Doctors have discovered that adding laughter to your life can make you healthier, too.
Methodology: Breastfeeding is the foundation of infant nutrition and lifetime healthExclusive breastfeeding for the first six months of life for optimum growth and health. In Hangzhou, China 500 mothers were recruited at birth for a randomised control ofthe influence ofthe type of growth chart on breastfeeding rates. The two growth charts used represented the CDC 2000 andthe WHO 2006 references. A total of 537 mothers were included in thepilotstudy, 273 in the first group (heavier growth chart) and 264 in the second (lighter) group.
The Power of Statistics in theDesignofaStudy
Jung-Chang Tang Shu-Hui Lee
National Chiayi University Gonchen Elementary School
An analysis ofthe power ofthe statistical methods used is very important in designing any research project or investigation. The major concepts regarding statistical power include the sample size ofthestudy, the desired detectable effect size, the specified Type I error rate, andthe sensitivities of statistical testing. The purpose of this article is then to explain the procedures a researcher should employ in order to make such statistical power explicit in thedesignof his or her study. Two empirical investigations are described in order to illustrate Type I and Type II error by examining sample size, statistical tests, measures, treatment effects, and variability within the subject groups of these two studies. Finally, some procedures for the consideration of statistical power in experimental design are suggested.
0.74282, 0.70246 and 0.74621, respectively, when the y-axis was CO 2 removal efficiency andthe x-axis was outlet biogas flow rate.
The purpose of developing the PDR was intended to desulphurize livestock biogas under ambient conditions and applied with the various biogas applications such as power generation, absorption chillers, or kitchen stoves. The higher the heat value, the more efficient the biogas applications. For onsite application, the load- ing volume of biogas must be increased with the enlargement ofthe size ofthe biogas desulphurization facility andthe hollow fibre CO 2 adsorption module. Thus, nitrogen gas adsorption cartridges might be needed and installed next to the hollow fibre CO 2
Pains are common symptoms among the elderly, especially those occurring at joints owing to
musculoskeletal disorders. Negligence upon them for a period of time would most likely result in further aggravation on all fronts surrounding the sufferers, for example, the activity level would drop, life quality be jeopardized, and in some cases, patients even become disabled. At a very high rate, these pains are further associated with degenerative types of diseases, and thus are persistent and even harder to cope with. Therefore, it is essential to alleviate the pain suffering and at the same time to oppose such
process using DEFORM software, and compared their results with experiments. Cho et al.  also used DEFORM software to studythedesign process ofthe cold forging ofa billet by forward and backward extrusion.
In the traditional hole-flanging process, a metal sheet must first be processed into washers. Next, the pressure plate must be fixed to the mould surface, and finally the punch pin must perform the extrusion on the billet hole edge. However, in this process, the low material utilization, transmission, andthe processing speed are very time-consuming, and it is impossible to achieve economic benefits from mass production. In order to enhance and improve the hole-flanging process. This study employs the auto-loading andthe forging mechanical characteristics ofa multi-stage former to studya hollow fastener with a thin flange during the cold forging process using steel wire as the raw material. The production speed is ten times higher than that ofthe traditional forming process.
Large sales 6,229,248 23,776
Small sales 101,895 1998
Combined totals 7,803,184 18,848
process in parallel. Experts provided qualitative assessment ofthe cases that were selected by the data mining based approach before auditors performed actual field audits, as the column data mining predicted suggests. The results from actual field audits were in the last column. The detailed assessment results are not reported here since they are protected by law. Results in dollars for different categories are reported in Table 9. As described earlier, auditors would concentrate their attention on Use tax, Sales tax, or both once they decided to conduct field audits. Therefore, there are different categories shown in Table 9. These results clearly show that the data mining based approach generated more revenue for the DOR. For example, in Table 9, the DOR assessed Sales tax of $23,776 in average for relatively large businesses. Please recall that the threshold for being a profitable audit was set to $1500 per case (for a 3-year audit period). The result achieved by the data mining based approach clearly proved that it was able to not only save costs and efforts but also generate more revenue. What is more, the manual audit selection process (used at the time ofthepilot project) was struggling with relatively small businesses and usually most cases generated less than $1500. Nevertheless, the average amount of assessed Sales and Use taxes achieved by the data mining based approach was $2504. Furthermore, if auditors decided to concentrate on Sales tax, the average assessed amount for relatively large businesses was $23,776 while that for relatively small businesses was $1998. Considering the threshold was set to $1500 per case, andthe average assessed amount of dollars was $18,848, revenue generated by the data mining based approach was over 12 times ofthe threshold that was associated with the average collection cost. These results demonstrated that data mining had the potential to efficiently and effectively perform more sophisticated tax audit selection.
Note to Practitioners—This paper was motivated by the problem of finding optimal process parameters for the TiO thin film but it also ap- plies to other different processes that need to get better process parameters by experiments. Existing approaches have trial-and-error or experimental design methods. The two methods are time- and cost-consuming, and could not guarantee to find the good process parameters. This paper suggests a procedure by combining both modeling and optimization methods to solve this problem. We employ the Taguchi method, the ANN, andthe GA to search for the optimal process parameters for a TiO thin film in the vacuum sputtering process. The result is quite promising. In future research, we will improve the adopted methods and apply the approach to other problems for optimal process parametersdesign. Please feel free to contact us, if you have any questions about this approach. We will do our best to help you.
Fig. 8 An illustration for MySQL database 6. Data processing ofthe medical monitoring system The data processing ofthe designed medical monitoring system consists of three sub procedures. The first part is that nurses deliver waking commands to WSN modules through the PC-based gateway in the ward. A waking command is written as ‘NodeWake, NodeID-PName’. If the sensor node receives a waking command, the corresponding sensor node and its equipped medical meters will be awaken from a sleeping mode. All the sensor nodes send a packet to the PCP when they received the waking commands. The PCP transmits the detecting commands to the awaked WSN modules. A detecting command is written as ‘VitalDetect, NodeID-PName’. After detecting vital signs, the data that includes various items (Node ID, Name, Systolic Pressure, Diastolic Pressure, Pulse, Oxygen Concentration, Body Temperature, and Time) is transmitted back to the PCP through wireless communication.
Sediment Bypass Tunnels (SBTs) are a sediment routing technique. During floods, sediment-laden water is conveyed through the tunnel to the dam tailwater. SBTs feature several advantages over other measures against reservoir sedimentation. First of all, SBTs have demonstrated to be quite effective with sediment bypass efficiencies of up to more than 90%, thus considerably extending the reservoir life, i.e. the theoretical duration until the reservoir is completely filled with sediment. Secondly, they have positive effects on downstream eco-morphology, because sediment conveyance may significantly decelerate or even stop riverbed incision and increase the habitat quality and morphological variability below a dam reservoir. Mainly sediments provided from upstream river reaches are conveyed through SBTs since remobilization of accumulated sediments in the reservoir hardly occurs. An SBT can thus greatly improve the sediment continuity despite river impoundment by dams. In this paper the main design features, operational aspects and eco-morphological effects of SBTs are presented.