Department of Civil Engineering (CE)http://hdl.handle.net/20.500.12228/222024-03-29T10:40:24Z2024-03-29T10:40:24ZAnalysis of Heavy Metal Concentration in Soils of a Waste Disposal Site in Khulna using Artificial Intelligence TechniquesSarkar, Shyamol Kumarhttp://hdl.handle.net/20.500.12228/7612020-02-04T21:00:15Z2019-09-01T00:00:00ZAnalysis of Heavy Metal Concentration in Soils of a Waste Disposal Site in Khulna using Artificial Intelligence Techniques
Sarkar, Shyamol Kumar
The collection of soil samples is labored and time consuming as well as the determination of heavy metal concentrations in laboratory was expensive. To these attempts, artificial intelligence techniques (AI) such as adaptive neuro-fuzzy inference system (ANFIS), support vector machine (SVM) and artificial neural networks (ANN) were implemented for the analysis of heavy metal concentrations in soils of a selected waste disposal site at old Rajbandh, Khulna. The aim of this study was to fix the functions, algorithms, optimization methods for AI techniques based on their best performance and then select a best technique for the analysis of heavy metal concentrations in soils. In this study, soil samples were collected from eighty-five locations at a depth 0-30 cm from the existing ground surface from the selected disposal site. In the laboratory, the concentrations of heavy metals of Pb, Cu, Ni, Zn, Co, Cd, As, Sc, Hg, Mn, Cr, Ti, Sb, Sr, V and Ba in soils were measured.
Result reveals the model with SCP, gaussmf, linear and hybrid was the best-fitted model of ANFIS for the prediction of heavy metal concentrations in soils. In addition, in SVM analysis, the model SVM-RBF with 15 folds was selected for the prediction of heavy metal concentrations in soils. In ANN, the model LT (Levenberg-marquardt and Tansig functions) with neuron structure 2-10-1 was selected. The accuracy of the predicted results were checked based on the acceptable limits of prediction parameters like R value, RMSE, MAPE, GRI and percentage recovery. Among all heavy metals analysis in ANFIS, the maximum R-value 0.999 was found with the minimum RMSE 0.12 for Sc indicating the best correlation in prediction of Sc in soils. The others value of prediction parameters (MAPE= 36.00, GRI=1.50, percentage recovery=123.43%) for Sc were found within the acceptable limits. In addition, in SVM analysis, maximum R-value 0.73 with RMSE 2.03 was found for Cu; while, maximum R-value 0.88 with the minimum RMSE 1.01 for As was found in ANN. The results demonstrated that ANFIS model was a reliable technique than that of other counterparts of SVM and ANN to analyse the heavy metal concentrations in soils with the acceptable degree of robustness and accuracy. Therefore, the performance of AI techniques may be expressed by the sequence of ANFIS > SVM > ANN. Here it can be noted that one can easily be computed the concentration of a particular heavy metal in soils by inserting GPS values (latitude and longitude) only in the developed rule viewer of ANFIS. Therefore, this newly developed model will further be helpful for other researchers in this line to analysis heavy metal concentration in soils of selected waste disposal sites.
This thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, September 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 154-160).
2019-09-01T00:00:00ZMicro-Characterization of Indoor Particulate Matter in Selected Areas of Jashore University of Science and TechnologyPatwary, Md. Helal Uddinhttp://hdl.handle.net/20.500.12228/7602020-02-04T21:00:13Z2019-07-01T00:00:00ZMicro-Characterization of Indoor Particulate Matter in Selected Areas of Jashore University of Science and Technology
Patwary, Md. Helal Uddin
Indoor air pollution has drawn considerable attention in recent years. Indoor air quality is very important for human health especially for vulnerable group of people (the asthmatic, the children and the elderly). The indoor environment can be subdivided into different micro-environments such as residents, transport, offices, educational institutions etc. and each may have a different source of indoor pollution. Indoor particulate matter has harmful impact on human health and environment. The finer the size of particles the higher the harmful impact. In this research work an attempt has been made for characterization of indoor particulate matter at three buildings named10-storied residential Tower, Administrative and Academic building of Jashore University of Science and Technology (JUST) campus.
In the dust sample, presence of heavy metals (Ti,Fe,Cu,Zn,As,Pb,Zr) and criteria air pollutant(Pb)was found. The concentration of PM10 (μg/m3) and PM2.5 (μg/m3) measured by Tactical Air Sampler (TAS) was found highest value (PM10, 170μg/m3 and PM2.5,103μg/m3) in Academic building among the three buildings. The reason is that this building is situated near road side and construction work is going on adjacent the building. Again concentration of PM2.5 is found higher inside than outside the building in all cases. Concentration of PM10 (130μg/m3) is found higher inside than outside (76μg/m3) in Administrative Building. Concentration of PM10 and PM2.5 in all cases exceeds WHO guideline limit (WHO guideline for PM10 in 24 hour- 50μg/m3 and 1 year is 20μg/m3; For PM2.5 in 24 hour- 25μg/m3 and 1 year is 10μg/m3 ) and in academic building exceeds Bangladesh standard both in outdoor and indoor(Bangladesh standard for PM10 in 24 hour- 150μg/m3 and 1 year is 50μg/m3). Concentration of PM10 in administrative building both in outdoor and indoor and 10-storied residential tower building in outdoor is within Bangladesh 24 hour standard but exceeds Bangladesh 1 year standard. In academic building exceeds Bangladesh standard both in outdoor and indoor (Bangladesh standard for PM2.5 in 24 hour- 65μg/m3 and 1 year is 15μg/m3). Concentration of PM2.5 in administrative building exceeds Bangladesh standard in indoor but in outdoor within 24 hour standard but exceeds 1 year standard. Concentration in 10-storied residential tower in outdoor within the 24 hour standard but exceeds 1 year standard.
In XRF analysis presence of Pb (667±0.19,ppm) and Ca (61340±919,ppm) was found highest in academic building PM. Inter elemental correlation was calculated. Strong correlation (R2 >0.90) was found Pb with Zr; Sr with Ca, Ti, Zn and As; Rb with K and Cu; As with Ca, Fe and Zn; Zn with Ti and Fe; Cu with K; Fe with Ca and Ti. Strongly correlated elements originated from same source such as re-suspended road dust, trace element of earth crust, cement, paint and other construction materials. Adequate control, management, housekeeping can minimize the exposure of indoor dust to occupants.
This thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, July 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 81-86).
2019-07-01T00:00:00ZRehabilitation and Flexural Strengthening of Reinforced Concrete Beams using External Steel ReinforcementMondal, Md. Omar Alihttp://hdl.handle.net/20.500.12228/5452019-10-03T21:00:13Z2019-01-01T00:00:00ZRehabilitation and Flexural Strengthening of Reinforced Concrete Beams using External Steel Reinforcement
Mondal, Md. Omar Ali
Rehabilitation of existing structures in the form of structural strengthening may be required due to decrease of load carrying capacity with aging, improper design or to accommodate with increased load requirements with time or codal change. Structural demolition can be reduced by applying strengthening technique to improve the capacity. This research investigated the flexural behavior of reinforced concrete (RC) beams rehabilitated with different strengthening techniques involving external steel reinforcement. The main focus of the study was to apply those strengthening techniques under service load condition. Twelve half-scaled beams were prepared and divided into six groups. The first group was used as control specimens while the other five groups were strengthened with different strengthening techniques. The control specimens were tested by 3rd point loading to find the ultimate load carrying capacity in flexure. Then all other beams from each of the five groups were preloaded with 65%-75% of the ultimate load to simulate the service load condition. Some initial cracks were formed in each beam due to preload before strengthening. After observation of the crack patterns, the preloading was released and the beams were ready for strengthening. Two groups were strengthened with 3mm thick external steel plate bonded with epoxy adhesive, of which the steel plate in one group was anchored by steel bolts in addition to the adhesive. Two different types of epoxy adhesive were used in two separate beams of each group. The 4th and 5th groups were strengthened with near surface mounted (NSM) external steel bars. The NSM bars in the 4th group were attached by epoxy adhesives while those in the 6th group were welded with the original bottom stirrups after removing the bottom concrete cover. The remaining group was strengthened by using external steel angle welded with the bottom stirrups after removal of the required concrete cover. Finally, the bottom concrete cover was cast again.
The average ultimate load carrying capacity of control beams in flexure was found to be 49.1kN. The ultimate capacity of strengthened beams with steel plate was observed to be 92.4kN for a specific adhesive type, which was as much as 88% higher than the control beams. The capacity was greatly influenced by the type of adhesives and the bond strength between steel plate and concrete. Anchoring the steel plate by steel bolts at both ends in addition to the epoxy adhesive further increased the capacity to 104% higher than the control beams and mode of failure switched from a brittle to a ductile nature. The capacity of beams strengthened with NSM bars varied from 101.9kN to 115.0kN depending on the type of the adhesives. Flexural failure occurred either by the separation of NSM steel bars by bond failure or by pure bending. The beams strengthened with external steel angles welded with bottom stirrups showed an ultimate flexural load capacity of 124.4kN and 116.8kN, which were 153% and 138% higher, respectively than the control beams. A ductile behavior was obtained when the welded connections in this type of strengthening did not fail. The ultimate capacity was 127.5kN and 134kN for the beams strengthened with external steel bars welded with bottom stirrups which were 160% and 173% higher than the control beams and 95% and 100% of their designed strength. The initial flexural failure pattern in the unstrengthened beams was transformed to an obvious shear failure pattern in that case. After normalizing the experimental results with respect to external steel ratio and grade, it could be concluded that the NSM method of flexural strengthening was more effective in comparison to the other methods. On the other hand, strengthening with external steel plate was more convenient and easier to apply although its capacity is slightly lower than the NSM method.
This thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, January 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 92-99).
2019-01-01T00:00:00ZFlow Characteristics and Environmental Flow Requirement of Gorai River in BangladeshHasan, Md. Mahmudulhttp://hdl.handle.net/20.500.12228/5332021-09-08T21:00:16Z2019-07-01T00:00:00ZFlow Characteristics and Environmental Flow Requirement of Gorai River in Bangladesh
Hasan, Md. Mahmudul
Environmental flow requirement certifies natural condition prominence of a river. Due to terrestrial location, rivers in Bangladesh have faces precise high flow in wet season and low flow in dry season. Since the current condition of a river flow characteristics has proven on historic flow data, so estimation of environmental flow requirements for the rivers are censoriously important for Bangladesh. The purpose of the research is to assess environmental flow requirement of Gorai River and to evaluate flow characteristics of the river through the comparison between past and recent time. Two stations are selected to assess the environmental flow circumstance for Gorai River system. The selected stations are Gorai Railway Bridge and Kamarkhali Transit station. There are several methods for calculating the environmental flow requirements of a river system. Three popular methods are used here for estimation of the environmental flow on the selected stations. The three methods are Mean Annual Flow (MAF) method, Flow Duration Curve (FDC) method and Constant Yield (CY) method. These methods are appropriate for hydrological attitude and in use of chronological flow data.
Daily discharge data of selected stations recorded by Bangladesh Water Development Board (BWDB) has been collected and analyzed for two periods i.e. G1 period (for the year 1984 to 1999) and G2 period (for the year 2000 to 2016), and IHA software (version 7.1) has been exercised. The analysis has been done according to MAF, FDC and CY methods. It is observed from the analysis that, the Mean annual flow of Gorai Railway bridge station is 1012 Cumec during 1984 to 2016, and Mean annual flow of Kamarkhali transit station is 795.1 Cumec during 1984 to 2016. As low flow season is the main concern, about 202.4 Cumec flow is required to maintain good condition for Gorai Railway bridge station and 159 Cumec flow is required for Kamarkhali transit station in MAF method. The relationship between the magnitude and duration of stream flows is presented by flow duration curve (FDC). FDCs are used mainly to set environmental flow purposes. Flow duration intervals are stated as percentage of exceedance, with zero corresponding to the highest stream discharge in the record (i.e. flood conditions) and 100 to the lowest (i.e. drought conditions). As low flow season is the main concern, the environmental flow requirement based on FDC in LFS is found as 290 Cumec for Gorai Railway bridge station and 167 Cumec flow is required for Kamarkhali transit station in FDC method. During the low flow season the minimum requirement based on FDC method is retained during both intermediate and high flow seasons but not for low flow season which is the main concern. Environmental flow considering CY method for Gorai Railway bridge station is found as 221.4 Cumec and for Kamarkhali transit station it is found as 162.85 Cumec. The flow found in CY method is close enough to environmental flow requirement obtained from MAF and FDC methods.
It is found that the estimated environmental flows of Gorai River at Gorai Railway Bridge station are 202.4 Cumec, 290 Cumec and 221.4 Cumec for MAF, FDC & CY method, respectively. By averaging these values, the environmental flow is estimated as 237.93 Cumec. In the Kamarkhali transit station of Gorai River the environmental flows are estimated as 159 Cumec, 167 Cumec and 162.85 Cumec for MAF, FDC & CY method, respectively. Thus the average value of environmental flow is estimated as 162.95 Cumec. It shows that insufficient flow condition remains from December to May in both of the stations according to the estimated environmental flow requirement. August and March are the highest and lowest flowing months respectively for both of the stations.
It is observed that, the river condition is good at the high flow season but when the flow comes in low flow season it becomes lower than the environmental flows required for good habitat quality. The flows in the month of January to May are less than the EFR required. The flows of these months are less than the severe degradation flow. It shows severe problems for both the stations. For the Gorai river, it is necessary to maintain the flow values more than the severe degradation throughout the year to sustain the habitat quality for the river. The three methods show different values for environmental flow requirement. The flow requirements in the low flow season for three methods are found lower than the required flow in both stations. It shows that the river is endangered for habitat quality in low flow seasons. In every method it proved that, the Gorai River has flow scarcity because of the low flows from upstream.
The chloride concentration is generally found higher in the month of November to June. These are the low flow season that includes post-monsoon and pre-monsoon period. It shows a higher value of chloride concentration. The highest individual one day chloride concentration is found as 511 ppm, and the average monthly highest chloride concentration is found as 152.8 ppm in the month of February. At high flow season the flows are higher in the month of July to October. It shows a lower value of chloride concentration. The lowest individual one day chloride concentration is found as 20 ppm, and the average monthly lowest chloride concentration is found as 37.5 ppm in the month of October. The chloride concentration at low tide and high tide shows no significant difference for the same day.
The chloride concentration in high flow season is not much less than the concentration of the low flow season for the exceedance 0% to 30%. For the exceedance probability 30% to 100%, it shows a big difference of chloride concentration among the seasons. The salinity for less than 100 Cumec discharge is higher and the salinity decreases with increase in the fresh water discharge up to 500 Cumec. The salinity shows lower value with high discharge upto 60% of probability of exceedance. After that from 60% to 100% probability of exceedance freshwater discharge value did not shows significant effect on salinity change. Small increase in fresh water discharge cause large change in salinity concentration from 5% to 60% probability of exceedance.
The environmental flow highlights the basic need of a river to sustain the assortment of natural status of hydrologic systems in order to defend native biodiversity. Indicators are anticipated to assess the complete ecological health of the river and the degree of hydrologic alteration triggered by a particular functioning policy. The condition of a river systems eventually rest on environmental flow constituents, which may change seasonally.
This thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, July 2019.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 82-84).
2019-07-01T00:00:00Z