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Item A Case Study of the Solution of Laminar Convective Boundary Layer Flow around a Vertical Slender Body with Transpirations(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2016-01) Razzak, S. Md. Abdur; Hossain, Prof. Dr. M. M. TouhidIn this thesis, a case of the similarity solution of laminar convective boundary layer flow around a vertical slender body with transpirations has been investigated. Firstly, the governing boundary layer partial differential equations have been made dimensionless and then simplified by using Boussinesq approximation Secondly, similarity transformations are introduced on the basis of detailed analysis in order to transform the simplified coupled partial differential equations into a set of ordinary differential equations. In the present thesis one of the important similarity case, out of four cases has been studied. Under the considered case, the transformed complete similarity equations are solved numerically by using computer software MATLAB. Further the flow phenomena have been characterized with the help of obtained flow controlling parameters such as suction/blowing parameter, buoyancy parameter, Prandtl number, body-radius parameter and other driving parameter. Finally, the effects of these involved parameters on the velocity and temperature fields are presented graphically. It is observed that a small suction or blowing played a significant role on the patterns of' flow and temperature fields.Item A Comparative Study on Fecal Sludge Management in Three Municipalities of Bangladesh(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2016-10) Islam, Md.Sahidul; Hassan, Prof. Dr. Khondoker MahbubThe sanitation needs of 2.7 billion people worldwide are served by onsite sanitation technologies, and that number is expected to grow to 5 billion by 2030. Bangladesh provides a striking example of progress to meet the Millennium Development Goal (MDG) - 7 to halve, by 2015, the “proportion of urban population with access to improved sanitation”. Open defecation has been reduced to only 1%, a milestone change from 42% in 2003. But the increase in fixed-place defecation has created an urgent need for Fecal Sludge Management (FSM) in the cities of Bangladesh, where most human waste is dumped untreated into waterways or onto marginal land, harming the health of the country’s poorest. The draft national regulatory framework identifies municipalities as responsible for FSM. This research was carried out in Khulna City Corporation, Kushtia Municipality and Jhenaidah Municipality. The study involved data collection, field visits, fecal sludge sampling and laboratory analysis, investigation on emptying, treatment and disposal services. Khulna City Corporation (KCC) covers an area of 45.65 km2 with tax-payee holdings of 66,257 of population 15,00,689. Manual sweepers are providing emptying services. KCC is providing both manual (by boggy) and mechanical emptying (vacutug) services since ten years. But there was no designated disposal site and the septage/fecal sludge was disposed here and there specially in drains which ultimately flows to river. 84% of the septic tanks have no soak wells and is connected directly to drains. Besides, City Corporation, Community Development Committee (CDC) have three smaller (1m3) vacutugs and those are much popular in services. Annual fecal sludge generation was estimated to be around 7,10,000 m3. Recently, KCC has started to construct a fecal sludge treatment plant (FTP) with financial assistance from Bill & Melinda Gates Foundation (BMGF). Kushtia Municipality is a class “A” municipality and recently been extended to total land area of 42.79 sq.km with population 3,75,149. In this municipality, 68% septic tanks have no soak well and are connected to drains. Fecal sludge generation was estimated to be around 104,581 m3/year. In this municipality, vacutug services have been launched since ten years. They have a treatment plant with two drying beds and coco-peat filter and compost is being produced here. Recently, the emptying demand has been increased tremendously, but capacity of the treatment plant is less. Thus, another FTP is under planning to meet the additional demands for FSM. Jhenaidah municipality is a small town of 32.42 Sq.km with 1,57,822 population. About 80% of the septic tanks have soak wells. Annual fecal sludge (FS) generation was estimated to be around 58,705 m3. A constructed wetland was built by the Department of Public Health Engineering (DPHE) in 2012 and handed over to the municipality for field operation and maintenance (O & M) using two vacutugs. But the municipality didn’t have any experience for the O & M of those and eventually left unused. Characterization of FS has been done for three municipalities. Experiments have been performed for sixteen wastewater quality parameters for each FS sample such as solids concentration, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), nutrients, pathogens, etc. The Solid contents in Fecal Sludge of these three towns varied between 3% to 6%. The range of COD concentrations were 7600-9600 mg/L. BOD5 concentrations were 819-1662 mg/L while the acceptable limit for disposal into inland water bodies is only 40 mg/L (ECR, 1997). Thus, it’s a big challenge to reduce the BOD5 in fecal sludge treatment plant for its ultimate disposal. Based on the entire value chain of FSM in three municipalities, proposals have been suggested for the overall improvement. There are 38.3%, 46% and 54.5% of pit toilets in Khulna, Kushtia and Jhenaidah, respectively. Placement of water seal, Y-junction of pit toilets and proper maintenance of the toilets can keep the toilets hygienic and improved. In Khulna and Kushtia municipalities, around 84% and 68% of septic tanks, respectively are connected to drains and thus stringent regulatory enforcement seemed imperative for its control and revision following Bangladesh National Building Code (BNBC). Manual emptiers can be registered by Municipal Authority so that only they can provide the services ensuring health and safety. Small devices such as Gulper and Diaphragm-Pump for emptying, Excrevator/Augur for extracting the hard solids from bottom of septic tanks, promotion and encouragement of local manufacturing process of Vacutugs, provision of secondary transfer station (STS), FSM as market based solution, simple treatment technology, raising Social Awareness, addressing Health and Safety issues, etc. have been proposed for the improvement of fecal sludge management in the study areas.Item A Compressive Sensing Approach to Analyze the Performance of wideband Cognitive Radio Networks(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-04) Ahmmed, S. M. Bulbul; Alam, Prof. Dr. Sk. SharifulIn the field of wireless communication systems, Cognitive Radio (CR) technology is the talk of the time for the best utilization of spread spectrum frequency. In the Wideband range, traditional Narrowband Sensing methods are not suitable to apply for performing Spectrum Sensing, as of making a single binary decision (Primary User present or absent) in the entire Wideband signal, thus cannot locate individual spectral opportunities that rely within the Wideband Spectrum. The Compressive Sensing (CS) can recover sparse signals at Sub-Nyquist rates and it depends on this principle of sparsity, so that a brief representation of the signal is possible when expressed in a suitable form. This research work has proposed a model of CR receiver sensing module which can be able to estimate a significant part (which is highly sparse among the segments of the spectrum) of the entire Wideband Spectrum with lower computational complexity. This propose work aims to analyze the compression ratio, i.e. M/N, with different number of Primary User (PUs) present in the wideband frequency from the Receiver Operating Characteristics (ROC) curves. Additionally, it is also analyzed that how the compression ratio, M/N characteristics varies with signal-t-noise ratio (SNR) in the wideband frequency from the ROC curves. This work investigates the probability of detection, Pd versus SNR for a fixed M/N and the throughput of a CR network against sensing period for a fixed frame length and vice versa. This proposed work also aims to find the requirement of less computational complexity and physical memory. Eventually, from the wide investigations through our proposed research work, it is found that the proposed method provides better throughput for fixed frame length as well as fixed sensing slot duration as well as frame duration the throughput is greater for shorter sensing time period. It can hopefully state in the final point that the proposed method proves its significance in CR system.Item A Cross-sectional Study of Work-Related Musculoskeletal Disorders among Construction Workers in Bangladesh(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2019-12) Rahman, Md. Sumon; Uddin, Prof. Dr. Md. KutubThe construction activities are closely associated with many occupational injuries. Work-related musculoskeletal disorders (WMSDs) are the most common occupational injuries faced by construction workers. WMSDs refer to a set of painful illnesses of human body muscles, tendons, nerves, ligaments, joints, etc. The construction workers also face injuries from the work site accidents. Most of the accident occurs in the construction site by falling objects on the worker’s body, workers fall from the height, electrocution, etc.. The workers feel pain in different body parts, sometimes become partial or permanent disable due to worksite accidents. There are many factors associated with the occupational injuries. Different researchers from different countries have studied the work-related musculoskeletal disorders of construction workers. As far, I know, no researchers have studied these types of disorders on Bangladeshi construction workers. Keeping this view in mind, the study investigated the work-related musculoskeletal disorders and accidental injuries among the Bangladeshi construction workers. This study also tried to find out the factors associated with Work-related musculoskeletal disorders (WMSDs). For this purpose, a cross-sectional study was conducted through a structured and Modified Nordic Questionnaire. The structured questionnaire contained the socio-demographic characteristics, the physical risk factors, environmental risk factors, and the equipment risk factors. The Modified-Standardized Nordic Questionnaire (MNDQ) is used to identify the musculoskeletal pains on different body parts over the previous year. All the questionnaires were two categories as an open-end and yes/no. In this study, a total of 450 (362 males and 88 females) construction workers aged between 18 to 65 years old were taken from the different construction sites at Jashore, Khulna and Satkhira, Bangladesh. Their main activities were mixing sand and cement, ironwork, lifting and carrying mortar, bricklaying, plastering, concrete laying and tiles fitting. The results found that overall 70.2% of workers reported that they had suffered at least one body part injury over the last 12 months. Among the nine body parts, lower back (49.80%) was the highest suffered body part and a thigh (9.60%) was the lowest suffered part. It is found the occurrences of work-related musculoskeletal disorders (WMSDs) were associated with socio-demographic characteristics such as gender, age, work experiences, working time, and working types. To minimize the work-related musculoskeletal disorders workers suggested to provide safety aid (26.70%), provide proper training and education (19.50%), to design hand tools in ergonomically (24.90%), ensuring good working environment (26.40%), and proper use of the personal protective equipment (21.80%). Most of the workers (32.20%) did not specify how to prevent work-related musculoskeletal disorders. About 60.70% of the participant experienced with accidents during their work in the construction site. Most of the accidents occurred by the falling objects on the worker’s body (19.10%), workers fall from the height (25.30%), electrocution (3.30%) respectively. Based on the data most of the workers (29.80%) injured in different body regions due to the worksite accidents. The workers also identified the causes of accidents such as personal negligence, lack of work experience, improper use of PPE (Personal Protective Equipment), absence of a good working environment, the overload of work, and lack of safety facilities. Above allcauses, the lack of safety facilities (42.80%) reported as the highest reason behind the accidents. It is found from this study that the prevalence of work-related musculoskeletal disorders and accidental injuries among the Bangladeshi construction workers are high. Finally, the author had made some recommendations for both workers and management of the construction sites.Item A Mathematical Meta Model of Academic Attainment Based on Class Attendance and Socio-Economic Changes(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2016-09) Naher, Nazmin; Jamali, Prof. Dr. A. R. M. Jalal UddinThe performance of students depend on many factors such as, attendance, motivation, level of engagement etc. which may be considered as the students attributes towards learning and some other attributes of the teachers on the process. No research is available relating the academic attainment and class attendance of our universities, especially at KUET where a 60% mandatory attendance is imposed to appear in the final examination. Though there exist many factors on student academic attainment, namely Class Test Marks and Final Grade, here we are interested and selected one important factor namely class attendance. There are many departments in this university (KUET) and a lot of subjects are taught. But Mathematics is common to all. Hence Mathematics is chosen for this study. This study is done among the students of first year and second year in several engineering departments regarding mathematics courses during the period 2000 -2013. It is of no doubt that for the existence of many proxy variables (Teacher’s attribute, student’s attribute, subjects, socio-economic environment etc.), it is very difficult to assess the impact of class attendance on academic attainment. Moreover, due to impose of mandatory percentage on class attendance, it becomes much more difficult to find out the impact of attendance on Class Test Marks as well as on Final Grade. In this study we have considered only existing old data (student attendance and academic performance), where the effect of proxy variables are ignored. Moreover, for better comparison as well as for finding some test statistics, all the data are normalized. We have rigorously studied about the correlation between class Attendance and Class Test Marks for each course. We have also investigated thoroughly in each course for the existence of correlation between class Attendance and Final Grade. In spite of 60% mandatory attendance, from the experimental results, it revealed that attendance has a great effect on academic attainments. But the effect is varying department to department as well as semester to semester. Though there exist correlations between Attendance and Class Test Marks but there exist relatively much strong correlation between Attendance and Final Grade in perceptive of all departments. It reveals that class attendance grow some intuitive knowledge to the students which affect on their final Grade. According to the existence of correlations, some Meta regression models are proposed regarding both Class Test Marks and Final grade depending on attendance. Though for the lacking of continuous data, we could not find out socioeconomic effect on academic attainment but it is revealed from the experimental study that introducing any new system effect on Attendance as well as academic performance.Item A Multi-Objective Genetic Algorithm with Fuzzy Relational Clustering for Automatic Data Clustering(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2016-12) Kundu, Animesh; Shill, Dr. Pintu Chandra.A Fuzzy relational clustering algorithm (FRC) based on multi-objective nondominated Sorting genetic algorithm (NSGA-II) called FRC-NSGA-II is proposed for automatic data clustering. A given data set is spontaneously promoted into an optimal number of groups in a precise fuzzy partition through the fuzzy relational clustering algorithm, FRC. FRC operates on a similarity square matrix which is generated by comparing the pair wise similarities between data points. Multi objective NSGA-II is employed to search for appropriate number of partitions for different cluster shapes. Moreover, two well-known cluster validity indices, compactness and separation, are optimized concurrently through multi-objective NSGA-II where compactness indicates variation between data within a cluster and separation means quantifying the separation between different clusters. Real encoding schema is used for variable length NSGA-II chromosomes representing the variable number of clusters. The simulation result on benchmark data sets exhibits that the proposed method gives promising results in the complex, overlapped, high-dimensional non-gene and gene expression data sets and it has better capability of determining well-separated, hyper spherical and overlapping clusters compared with other existing clustering algorithms.Item A New Approach to Design Microstrip Low Pass Filter(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2015-07) Rafiquzzaman, G. M.; Mollah, Prof. Dr. Mohammad NurunnabiWith the emergence of novel wireless technologies, the demands for larger bandwidth, high efficiency and high capacity RF and microwave devices have been growing tremendously. The recent implementations in solid state and semiconductor materials give us hope for future applications. It should be remarked that although many of the ideas could have been proposed much earlier, it is only recently that they were identified or demonstrated due to various technological advances. The electromagnetic bandgap (EBG) is introduced to improve the performances of existing RF active and passive devices. Electromagnetic Band Gap (EBG) structures produced a wide variety of design alternatives for researchers working in the area of microwave and photonics. The focus is now towards on finding real applications combined with detailed modeling. Due to the incredible potential of EBGs, there are huge applications in which they can be used. New companies have also started to exploit the commercial potential of this technology. This thesis describes the planar EBG structures in the forms of conventional circular and rectangular photonic bandgaps (PBGs) and dumbbell shaped defected ground structures (DGSs). Novel PBGs in the form of non-uniform Binomial and Chebyshev distributions of unit PBG cells have been proposed. This novel PBGSs contains fewer ripples with lesser height or ripple free passband and wide stopband properties, which are very useful to suppress higher order harmonics in the lowpass filters (LPF). The dumbbell shaped DGSs study has been described with the gap width and length and the size of dumbbell slots. Some novel designs have been proposed such as; non-uniform dumbbell shaped DGSs with Binomial and Chebyshev distribution, hybrid dumbbell shaped DGS and PBGS and modified hybrid dumbbell shaped DGS and PBGS configurations. The novel designs perform better than the conventional DGSs reported in the literature. The DGSs yield perfect LPF responses with negligible passband ripples and extremely wide stopband. In this thesis, we have investigated on uniform circular, rectangular and dumbbell shaped DGS structures with different filling factor (FF). Therefore, FF is not a single valued parameter. In our study, we have defined the FF as the ratio of central dumbbell shaped DGS element and inter-element spacing. And then for the better performance, we have focused on different Binomially and Chebyshev distributed dumbbell shaped DGSs. This research conveys the performance of low pass filter using those distributions at about 4 GHz cutoff frequency. These distributions remove the unwanted insertion loss in the band rejection region. Sufficient explanations have been provided to validate the total research works in the thesis. Finally, comparing the insertion loss (IL) and return loss (RL) performances of the LPFs with binomially and Chebyshev distributed dumbbell shaped DGSs and hybrid DGSs. Binomially distributed DGSs and hybrid DGSs provide improved performance than conventional PBGSs and Chebyshev distributed dumbbell shaped DGSs in terms of suppression of the ripple in the passband and return and insertion-loss bandwidths.Item A New Approach to Grow High Quality Bulk lnxGa1-xAs Crystal by Multi-component Zone Melting Method(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2005-12) Rahman, Mohammad Shaifur; Islam, Dr. Md. RafiqulAn analytical study has been carried out to grow high-quality bulk InGaAs crystals by the two-step multi-component zone melting (MCZM) method. Characterization of bulk InGaAs crystal grown by the two-step MCZM method has confirmed the existence of large amount of strain of the order of 10 in bulk InGaAs crystal due to approximately exponential variation of composition from 0.06 to 0.29 in the first step growth process of the two-step MCZM technique. From the experimental evidence, it has been confirmed that the composition-dependent strain is associated with the breakage issue in the MCZM grown crystals. Using an axially symmetrical strain model, the quantitative amount of strains and their distributions have been studied for various compositional profiles including the currently used profile. In addition, the spatial variations of strain components for various compositional profiles have been analyzed using the twodimensional strain maps. The strain values and their distributions corresponding to the various compositional profiles have been compared and a suitable compositional profile has been proposed to grow compositionally homogeneous high quality bulk InGaAs crystals using the MCZM method. Further, from the dependency of the strain values with the crystal length and diameter, the possibility of the growth of large-size crystals has been investigated. It has also been studied that the proposed compositional profile allows achieving the growth parameters easily for the two-step MCZM growth process.Item A New Concept in Modern Industry Sector, “Virtual Industry Model”(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-12) Badiuzzaman, Md.; Rafiquzzaman, Dr. Md.Virtual office has become a popular and desired office management system for technologybased low-cost office management system. This virtual management system is a new way of working that enables the virtual worker to work outside the walls of the traditional office. In this system, all the administrative functions of an organization are not necessarily geographically centered in one office. The process of designing and implement a low cost and effective "Virtual office management system" has been introduced in this work. The total system works using software which is named “Virtual Industry Model.” The software contains a secure database system and another computing method as required for industry. It is also interesting that using software and the total process will be automated and computerized what is a big deal in the industrial process. Finally, the system was applied to manufacturing, production and service operations. The results show that from the viewpoint of decision making, product design, production planning, production control to marketing, they were able to save their, time, their money and found the operation management easier.Item A Novel Sensor for Simultaneous Detection of Dihydroxybenzene Isomers(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2016-08) Tonu, Nusrat Tazeen; Yousuf, Prof. Dr. Mohammad AbuA novel, facile and low-cost electrochemical technique for the detection of dihydroxybenzene isomers (DHBIs), catechol (CC), hydroquinone (HQ) and resorcinol (RS), in aqueous system was developed. An attempt was made for the analyses of HQ, CC and RS in the same aqueous system by UV-Vis spectroscopy. UV-Vis spectrum of CC, HQ and RS exhibited absorbance maxima in PBS supported aqueous solution at 275.4, 288.6 and 273.2 nm respectively. But in the possible binary and ternary mixture of CC, HQ and RS, UV-Vis spectra showed single absorption peak instead of two and three separate peaks respectively. So, simultaneous detection of DHBIs was impossible by UV-Vis spectroscopy. Three electrodes electrochemical system was employed which was controlled by computer supported auto potentiostat. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were adopted as detection techniques. 2B pencil collected from the local stationary shop was used for fabricating working electrode termed as pencil graphite electrode (PGE) in the experiment. PGE electrode was characterized by Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDX). From the SEM it was seen that surface morphology of PGE was not smooth as conventional glassy carbon electrode (GCE) instead contained huge grooves as well. It indicates that the graphite rod of the pencil was not pure crystalline. From EDX it was seen that PGE surface are impure as propped up by SEM. Results showed that it is composed of 79.39% carbon, 10.03% Si, 3.06% O2, 3.49% Al, 2.68% Fe and trace amount of Mg and Ca. So a lot of defects and few foreign materials were present in the surface of PGE confirmed by both SEM and EDX. PGE was first modified electrochemically by ionic liquid (IL), [1-Hexylpyridinium hexafluorophosphate (HIL) or 1-Butyl-3-Methylimidazolium hexafluorophosphate (BIL)] and then used in detection analyte by CV and DPV. Modified electrodes were termed as HIL-PGE and BIL-PGE in total working process. Modified electrodes showed excellent electroanalytical activity effect on the redox reaction of DHBIs. Total analyses and detection processes were performed in phosphate buffer solution (PBS) at pH 7.0 which was used as supporting electrolyte. The influences of scan rate and concentration on the redox behavior of HQ, CC and RS in both HIL-PGE and BIL-PGE were discussed. The anodic peak current versus the concentration of HQ, CC and RS showed a linear relationship. The variation of peak current was also plotted with Square root of scan rate. The electrochemical processes were diffusion controlled. Variation of peak potential separation was plotted with scan rate. The anodic peak potential shift was positive, which was due to IR drop. HIL-PGE showed splendid selectivity and strong anti-interference for detection of HQ, CC and RS simultaneously in aqueous media with excellent results. The limit of detection (LOD) was calculated by signal-to-noise ratio (S/N = 3). In simultaneous detection, the LOD for HQ, CC and RS at HIL-PGE were 6.38 μML-1, 4.56 μML-1 and 19.6 μML-1 respectively and those were 9.09 μML-1, 8.15 μML-1 and 26.78 μML-1 respectively at BIL-PGE. The sensitivity for HQ, CC and RS is 448.49 μA/mM/cm2, 627.35 μA/mM/cm2 and 146.10 μA/mM/cm2 respectively at HIL-PGE and 525.21 μA/mM/cm2, 585.68 μA/mM/cm2 and 178.0 μA/mM/cm2 respectively at BILPGE in simultaneous detection.Item A Precise Evolutionary Approach to Solve Multivariable Functional Optimization(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-06) Islam, Md. Robiul; Akhand, Dr. Muhammad Aminul Haque.Mankind has been facing optimization problems throughout history and making the great efforts to solve them. Optimization problems, in simple terms, are to find the best or close to the best solutions to the problems. The task of optimization in solving engineering problems is also crucial and the biologically motivated computing techniques have waxed and waned over the period of time. Evolutionary approach is a common technique that uses natural phenomena like biological genes, population, mating etc., to solve optimization problems. In an evolutionary approach a population of solution is maintained and tries to improve the solutions for better performance as better fitted species survive. Among several different methods of evolutionary approach Genetic Algorithm (GA) is the most popular due to its simplicity. Genetic Algorithm is a stochastic search and optimization method imitating the metaphor of natural biological evolution. It works on the population of individuals instead of single solution. Although GA draws attention for functional optimization, it may search same point again due to its probabilistic operations that hinder its performance. Generally, GAs are time-consuming in computing due to the large number of fitness function evaluations required and the implementation of many operators and parameters, but sometimes they cannot produce the desired results. it is always challenging for GA for functional optimization to achieve optimal solution in acceptable time. In this thesis, we make a novel approach of standard Genetic Algorithm (sGA) that minimizes the shortcomings of sGA. The proposed method is called Precise Genetic Algorithm (PGA). The primary motivation for the proposed PGA is to ensure the successive convergence in optimization problems to reach optimal solution with a minimal time. PGA searches the target space efficiently and it shows several potential advantages over the conventional GA for solving both single and multivariable functional problems. We have shown that the proposed method reveals the good performance in the context of the quality and the time needed to reach the optimal solutions compared to sGA.Item A Scalable Storage System For Structured Data(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2017-12) Omar, Mehnuma Tabassum; Hasan, Dr. K. M. AzharulArray based storage system is a key choice of many featured applications such as Scientific, engineering, and financial computing applications; for their easy maintenance. However, the lack of scalability of the conventional approaches degrades with the Dynamic size of data sets as they entail reallocation in order to preserve expanded data Velocity. To maintain the velocity of data, the storage system must be scalable enough by Allowing subjective expansion on the boundary of array dimension. Again, for an array based storage system, if the number of dimension and length of each dimension of the Array is very high then the required address space overflows and hence it is impossible to Allocate such a big array. We demonstrate a dynamic scalable array storage scheme Namely Scalable Array Indexing (SAl) that can be an efficient choice of large volume Dynamic data management by removing the problems of the existing ones. The SAl converts an n dimensional array to 2 dimensions. Traditionally, the dynamic array models need indices for each dimensions. Since, SAl is a 2 dimensional dynamic model it reduces the index overhead significantly and compromises relatively faster data accessing. We also propose another scalable structure based on the SAl scheme to increase storage utilization. We named the structure as Segment based Scalable Array Indexing (SSAI). Using our SSAI structure, we also offer an efficient encoding with good comparison ratio and range of usability. All the operations are presented with sufficient theoretical analysis and experimental resultsItem A Study into the Use of the Dysfunction Mode and Effects Critical Analysis (DMECA) in a Power Plant(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2009-01) Rahman, Azizur; Uddin, Prof. Dr. Md. KutubDysfunction Mode and Effect Critical Analysis (DMECA) is a well-established tool for assessing dysfunctions regarding the quality of maintenance and production processes. It is conceptually same as the Total Quality Management (TQM) tool of Failure Mode and Effect Critical Analysis (FMECA). It helps to focus on core challenges while still including a wide range of dysfunctions. Since the nature of dysfunctions and quality issues are very similar, the general idea and framework of a DMECA may be adapted successfully to remove dysfunctions in management process. The DMECA approach, to determine and analyze possible dysfunctions in complex management processes, was developed by Massimo Bertolini, et.al. [2]. They recommended that this method can be applied to various fields such as manufacturing industry, power plant, gas generating plant even where the measure of management process efficiency is more difficult. The analytical tool DMECA works according to the new ISO 9000:2000 standards and the Total Quality Management (TQM) principle concerning the 'process approach'. In this study, DMECA method is applied to determine and analyze the possible dysfunctions in complex management process of a power plant. According to the literature reviewed, probably this is the first to use the DMECA in a large power plant. DMECA is used to analyze each potential dysfunction mode for each elementary activity constituting the plant processes, to identify the subsequent effects. A list of priority interventions of the dysfunction modes then decided. The evaluation of the priorities are utilized to create a classification of the potential dysfunction modes according to a criticality parameter obtained by the combination of severity of the consequences, probability that the dysfunction occurs and chances that it can be detected. The process break-down structure defined during the process identification phase (reported in Figure 4.4 for the firms' processes) 09 sub-processes and 57 activities of job management process were identified. For each activity, possible dysfunctions had established and 175 potential causes have been identified for the whole process of 'job management'. A code number was assigned to each dysfunction with the same criteria as used to map the processes. In order to conduct a criticality analysis of dysfunction, the judgment criteria is defined, by which the unwanted event was assessed. The conversion tables (Table 4.2, 4.3, 4.4 & 4.5) were suggested to translate linguistic judgments into numerical values to obtain a Risk Priority Number (RPN). Thus, it will be possible to judge and evaluate the criticality of the dysfunction causes. Data for this study were collected from the respondents of the study area by using the questionnaire prepared (Appendix A). The interviews were made group wise in the power plant during their work and leisure time with the permission of interviewee as well as management. Each personnel completed the questionnaire independently, with the support of Table 4.5. Mean values (from all questionnaires) of the three parameters; occurrence dysfunctions (OD), Detectability dysfunctions (DD) and severity dysfunctions (SD) for each dysfunction were calculated. Finally, the respective RPNs were obtained as RPN = ODx DD x SD. The calculated RPN values are provided in table 4.6. These products may be viewed as a relative measure of the management dysfunctions. The RPN values can range from 1 to 1000, with 1 being the smallest management dysfunction possible and 1000 being the biggest management dysfunction possible. These values were then used to rank the various causes in the dysfunctions. In case of process with a relatively high RPN, the engineering team must make efforts to take corrective action to reduce the RPN. Likewise, because of a certain dysfunction has a relatively low RPN, the engineering teams should not overlook the causes and should not neglect an effort to reduce the RPN. This is especially true, when the severity of a cause is high. In this case, a low RPN may be extremely misleading, not placing enough importance on a cause where the level of severity may be disastrous. In general, the purpose of the RPN was to rank the various causes documented. The smaller the RPN the better - and - the larger the worse. Dysfunction causes and their relative weights were investigated for each activity in order to determine the most critical and to decide improvement actions. There are only 25 causes of dysfunctions those are critical amongst 175 cusses. The beauty of DMECA method is that it permits to identify and eliminate particular Dysfunctions and simultaneously it will correct or eliminate other problems or inefficiencies indirectly. Therefore, at the end of the DMECA structured process analysis, we obtained schemes where relatively few corrective actions can solve multiple dysfunctions (Table 5.2). This was possible because there were a strong interrelationship between management processes and activities. The main advantage of the methodology is its applicability to the managerial processes of each organization (i.e., firms, public services, local agency or government). In particular, DMECA is a valid technique to evaluate processes efficiency and effectiveness in the field of service sector where measuring, monitoring and correcting the possible dysfunctions in managerial processes are critical to improve the performances of production and maintenance. To analyze the managerial dysfunctions in any organization the DMECA approach is very effective and it involves low cost as it is found in this research work. So, it is a cost effective and can be applied to identify management personnel deficiencies which in turn will be helpful for uninterrupted production and/or maintenance. It identifies, access and ranks dysfunctions that are challenging to eliminate. Thus, the method prevents the consumption of time and cost of production and/or maintenance. In this study an application of the DMECA technique applied in an important power plant (maintenance and production for electricity) to analyze, to evaluate and to improve job management process efficiency. Finally a number of recommendations are made to the management to implement the research findings to the plants. At last but not least some recommendations are also made for further study.Item A Study of Sectionally Pseudocomplemented Lattice & Boolean Algebra(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-02) Hasan, Md. Nazmul; Azad, Prof. Dr. Md. Abul KalamThis thesis studies the nature of a sectionally pesudocomplemented lattice and Boolean Algebra. Lattice theory is a part of Mathematics. Boolean algebra and Boolean function is an important of lattice theory. A nonempty set P together with a binary relation R is said to form a partially order set or a poset if the following conditiois hold: (i) Reflexivity (ii) Anti-symmetry (iii) Transitivity. A poset (L, ≤) is said to form a lattice if for every a, b ε L if a˅b and a ˄ b exist in L. A lattice is said to be complemented lattice if every element has a complement. Let L be a bounded distributive lattice, let a ε L an element a* ε L is called a pseudocomplement of a in L if the following conditions holds: (i) a ˄ a* = 0 (ii) ∀ x ε L, a ˄ x =0 implies that x ≤ a* . A complement distributive lattice is called a Boolean lattice. Since complements are unique in a Boolean lattice as an algebra with two binary operations A and v and one unary operation '.Boolean lattices so considered are called Boolean algebra. Moreover we can discuss on relatively pseudocomplemented Lattices. In this thesis, we have given several results on seetionnally (relatively) pseudocomplemented lattices which certainly extended and generalized many results in lattice theory. In chapter one is to outline and fix the notation for some of the concepts of lattices which are basic to this thesis. Some more definitions and formulate results on a orbitrary lattices for later use. We have considered this section as the base and background for the study of subsequent sections. For the background material in Lattice theory we have refered the readers to the of G. Birkoff [14] G. Gratzer [15] and V.K. Khanna [24] and several authors. In chapter two, we have given a description of difference classes of lattices. We have also studied normal lattices and distributive quasi-complemented lattices. Generalized stone lattices have been studied by H. Lakser [16,17], K.B Lee [20] and many other authors. We have given a characterization of minimal prime ideals of a sectionally pseudocomplemented lattices. Then we have shown that a distributive Lattice L with 0 is generalized stone if and only if it is both normal and sectionally quasi-complemented. In chapter three introduces the concept of relative annihilators in lattices. Relative annihilators in lattices were studied by several authors including Mandelker [21] and Verlet [22]. B.A. Davey [1] has used the annihiiators in studying relatively normal lattices. Here we have studied the relative annihilators in lattices. In terms of relative annihilators, we have characterized modular and distributive lattices. Relatively stone lattices have been studied by several authors including Mandelker [26], T.P. Speed [23] Gratzer and Schmidt [15]. Here we use given several characterizations of relatively stone lattices, which are certainly the generalization of above authors work. We have also shown for a distributive lattice L in which every closed interval in pseudocomplemented is relatively stone if and only if any two incomparable prime ideals of L are comaximal. In chapter four, we have studied lattices with the greatest element 1 where on each interval [a,1] an antitone bijection is defined. We have characterized these lattices by means of two induced binary operations proving that the resulting algebras form a variety. The congruence properties of this variety and the properties of the underlying lattices are investigated. We have shown that this variety contains a single minimal subquasi variety join-lattices, whose principal filters are Boolean lattices, were used by J.C. Abbott [13]. We have introduced a further generalization of this concept, defining the notion of a lattice with sectionally antitone bijection. We have also introduced Residuated Lattices studied by Ward and Diworth [26] and several authors. Two mono graph contain a compendium on residuated lattices. They are that by Blyth and Janowitz [2]. In this paper we will compare a certain modification of a residuated Lattice. In chapter five, It is shown that every directoid equipped with sectionally switching mappings can be represented as a certain implication algebra. The concept of directoid was introduced by J. Jezek and R. Quackenbush [19] in the sake to axiomatize algebraic structures defined by on upward directed ordered set. In certain sense, directoids generalize semilattices. In chapter six. We have studied switching Mapping introduced by Chajda and Emanovsky [3]. A mapping f of [a, 1] onto itself is called switching mapping if f(a) =1 and for x ε [a,1], a ≠x ≠1 in the section[q,1] is determined by that of [p,l], we say that the compatibility condition for antitony switching mappings and connection with complemention in sections have been shown.Item A Study of Single and Multi Step Methods To Solve Differential Equations(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-04) Khanam, Mary; Hossain, Prof. Dr. Mohammad ArifHere the task was to study single and multi step methods to solve differential equations. As Rungc-Kutta method. a single step method has some property to represent a larnily so attention has been given to that method. It was found that to establish the method of any order the number of unknowns are more than the number of available equations. Thus there are options to choose certain values as someone wants (keeping in mind about the conditions). The opportunity has been taken and FIVE formulas of different orders, two fifth, two sixth and one seventh, has been proposed. Problems are solved to verify their capability and strength and it is found that the percentage errors with respect to the exact values are comparable in magnitude with respect to some available same order methods. In case of multi step methods, extensions in both explicit and implicit methods in terms of order are done. It is done keeping in mind that the extension in order will reduce the error. Extensions in Adams- Bash forth and Adams-Moulton formulas up to TENth order are done and with eighth order of both of them a problem is solved to demonstrate the strength of the extension of these predictor-corrector methods.Item A Study of Structural and Magnetic Properties of Mg-Cu Mixed Spinel Ferrites(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2016-04) Podder, Apurba; Sikder, Prof. Dr. S. S.Mg-Cu ferrites are well-known technological magnetic materials finding applications in various electrical devices. The present work is focused on the influence of substitutions and sintering temperature on structural and magnetic properties of Mg-Cu ferrites. Mg1- xCuxFe2O4 where x=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 samples have been prepared by conventional ceramic method, sintered at 1100°C, 1200°C and 1200°C (quenched). Some physical properties such as lattice parameters, density, porosity, magnetic properties such specific magnetization and hyperfine magnetic field. The structural phase identification was carried out by X-ray diffraction (XRD), microstructure analysis of the samples following scanning electron microscope (SEM), specific magnetization measurement by vibrating sample magnetometer (VSM) and Mössbauer spectroscopy analysis. The X-ray diffraction analysis revealed that all the samples are crystallize in single phase cubic spinel structure. It was found that lattice parameter and porosity decreases with the Cucontent. It was observed from the microstructure study that the grain size increase with the increasing Cu-content. Thoughout the investigation it has also been found that grain size increases with increasing sintering temperature. Magnetization measurements have been accomplished by VSM. It was found that saturation magnetization increases with Cu-content with high value of 36.77 emu/gm for x = 0.5 at sintered temperature 1200°C (quenched), as well as microstructure grain size increases and grain growth clear visible. Interesting experimental results on magnetization at different sintering temperature have been found. Other structural and magnetic properties such as chemical isomer shift, quadruple splitting and hyperfine field were determined by Mössbauer spectroscopy. The velocity scale of a thin 57Fe sample and the isomer shifts are given relative to the centroid of the spectrum. The shifts of Fe atoms in all Mg-Cu ferrites sample behave trivalent ions. The spectrum for the Mg1-xCuxFe2O4 ferrites consists of six lines which are broad as compared with Mössbauer spectrum of a pure 57Fe samples. One of the magnetic signals is a sextet typical of those associated with a good ferromagnetic at room temperature. In a ferromagnetic order all Fe with antiparallel behavior is consistent with a diluted exchange coupling between magnetic Fe-ions on the tetrahedral site to octahedral site.Item A study on 0-distributive nearlattice(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2014-11) Rahman, Md. Zaidur; Rahman, Prof. Dr. Md. BazlarIn this thesis study of the nature of the 0-distributive nearlattices is presented. By a nearlattice S we will always mean a meet semilattice together with the property that any two elements possessing a common upper bound, have a supremum. Cornish and Hickman [14] referred this property as the upper bound property and a semilattice of this nature as a semilattice with the upperbound property. Cornish and Noor [15] preferred to call these semilattices as nearlattices, as the behaviour of such a semilattice is close to that of a lattice than an ordinary semilattice. Of course a nearlattice with a largest element is a lattice. Since any semilattice satisf'ing the descending chain condition has the upper bound property, so all finite sernilattices are nearlattices. In lattice theory, it is always very difficult to study the non-distributive and non-modular lattices. Gratzer [20] studied the non-distributive lattices by introducing the concept of distributive, standard and neutral elements in lattices. Cornish and Noor [15] extended those concepts for nearlattices to study non-distributive nearlattices. On the other hand, J.0 Varlet [66] studied another class of non-distributive lattices with 0 by introducing the concept of 0-distributivity. In fact this concept also generalizes the idea of pseudocomplement in a general lattice. This thesis extend the concept of 0-distributivity in a nearlattice to study a larger class of non-distributive nearlattices. A nearlattice S with 0 is called 0-distributive if for all x,y,z ε S with x˄y=0=X˄Z and y˅z; exists imply x˄ (y˅z) = 0. Chapter 1 gives a detailed description of nearlattices. Here we discuss ideals, congruenees, SemiBoolean algebra and many other results on nearlattice which are basic to this thesis. In Chapter 2 we introduce the concept of modular element in a nearlattice. Gratzer and Schmidt [23] introduced the notion of some special elements, e.g. distributive, standard and neutral elements, to study a larger class of non-distributive lattices. Then Cornish and Noor [15] used these concepts to nearlattices. Again Talukder and Noor [64] introduced the notion of modular elements in a join semilattice directed below. The notion of modular element is also applicable for general lattices. In this chapter, we have introduced the concept of modular and strongly distributive elements for nearlattices. i-Iere we have given several characterizations of modular and strongly distributive elements. By studying these elements and ideals we obtained many information on a class of non-distributive nearlattices. Chapter 3 and 4 are the key chapters of this thesis. In Chapter 3 we introduce the 0-distributivity in a nearlattice with 0. We include several characterizations of distributive nearlattices. We prove that a nearlattice S with 0 is 0-distributive if and only if all maximal filter of S are prime. We also show that S is 0-distributive if and only if i(s),the lattice of all ideals of S is pseudocomplemented. Then we include some prime separation properties. In this chapter we also include the notion of semi-prime ideals by extending the notion of 0-distributivity. In lattices, the notion of semi-prime ideals was given by Y. Ray [52]. By using these semi-prime ideals, we generalize the prime separation theorem of nearlattices in terms of annihilator ideals. Finally, we extend the concept of Glivenko congruence for 0-distributive nearlattices as well as for semi-prime ideals to establish a generalized version of prime separation theorem. In chapter 4 we discuss different properties of 0-distributive nearlattices and included several characterizations of these nearlattices Annulets and u-ideals in a distributive lattice have been studied extensively by Cornish [13]. Recently Ayub Ali, Noor and Islam [4], Noor, Ayub Ali and Islam [41] extended this concept for distributive nearlattices. In this chapter we study the annulets and a-ideals in a 0-distributive nearlattice. We give several characterizations of a -ideals. We also include a prime separation theorem for α -ideals. Finally we show that a 0-distributive nearlattice is quasicomplemented if and only if A0(S) (the dual nearlattice of annulets) is a Boolean subalgebra of A(S), where A(S) is the set of all annihilator ideals of S. Moreover, S is sectionally quasicomplemented if and only if A0(S) is relatively complemented. Chapter 5 brings the notions of 0-modular nearlattices. Ayub Ali, Hafizur Rahman and Noor [5], Jayaram [30], Noor, Ayub Ali and Islam [41] and Varlet [65] have studied different properties of 0-distributivity and 0-modularity in lattices and in semilattices. In this chapter we extend their work and include several characterizations of 0-modular nearlattices. Many mathematician including Cornish [Ii] have studied the normal lattices and p-algebras in presence of distributivity. Recently Nag, Begurn and Talukder[38] studied them in presence of 0-dirtributivity. They have generalized many results of S -algebras and D -algebras. Since the idea of pseudocomplementation is not appropriate for a nearlattice, we study the sectional pseudocomplernentation for a nearlattice. In chapter 6 we extend and generalize some results of Nag, Begum and Talukder [38] on D –algebras and S -algebras. We prove that every [0, x] , x ε S is an S -algebra if and only if it is a D -algebra where the nearlattice S is sectionally p-algebra with the condition that [o, x] for each x ε S is 1-distributive and S is 0-modular. We conclude the thesis by giving a characterization of sectionaly S-algebra whenever [0,x} for each x ε S is 1-distributive.Item A Study on Big Data Management Strategy Using Fog Computing(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-11) Islam, Tajul; Hashem, Prof. Dr. M.M.A.In modern ages, data is increasing day by day using internet of things for various purposes. Data intensive analysis is the major challenge because of the ubiquitous deployment of various kinds of sensors. Traditional cloud computing infrastructure is not enough for processing these large amount, variety or velocity of data that means big data. Traditional cloud computing structure is geographically centralized. Balancing load for big data is a crucial issue. A preprocessing stage is necessary to handle these big data for real time service oriented application. In this thesis, a big data management strategy is proposed using a preprocessing stage that is fog computing. Providing real time services from cloud is too many time consuming for big data. Here, Fog Computing plays a vital role. The maximum functions of processing data are implemented outside of cloud in the case of Fog Computing and one thing considered in Fog Computing is that here memory of fog devices is very little. So, a well-organized communication system is needed for data processing. Here, in this work an affordable, robust and secure power supply or third party memory management has been suggested which is Smart Grid and Smart Local Grid. The smart grid and smart local grid or third party memory management support the customer's real time services using fog infrastructure. In this work a hierarchical architecture has been proposed for creating well-organized communication system for data processing in the case of smart grid and smart local grid or third party memory management using fog infrastructure or nodes. For task scheduling of nodes in case of fog infrastructure queue based scheduling technique is used. In this work, an effective result for big data management and providing real time services has been found. Here, different parameters such as network latency, throughput have been used for measuring performance in real time services. The overall network latency is minimized and throughput is increased in case of fog computing.Item A Study on Complemented Lattices and Boolean Function(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2010-06) Das, Kishore Kumar; Rahman, Prof. Dr. Md. BazlarIn this thesis the nature of Complemented lattice and Boolean function is studied. Lattice theory is a part of Mathematics. In Modern algebra, Abstract algebra and Boolean function are Lattice theory play important role. A non empty set P together with a binary relation R is said to form a partially ordered set or a posel if the following conditions hold: Reflexivity Anti-symmetry Transitivity A poset (L≤) is said to form a lattice if for every a, b ϵ L if Sup {a,b} and Inf { a,b}exist in L. A lattice is said to be complemented lattice if every element has complement. In this thesis we give several results on complemented lattice, Boolean function and Boolean algebra which will certainly extend and generalize many results in lattice theory. The thesis contains four chapters. Chapter one: We have discussed the basic definition of set, partially order set, relations, functions etc. Chapter two: We have discussed lattice, sublattice, convex sublattice, complemented lattice, ideal, Filter, Prime ideal, Principle ideal and Principle Dual ideal. We have proved that two bounded lattices A and B are complemented if and only if A x B is complemented. In this chapter we have also discussed the definition of upper bound, least upper bound, lower bound, greatest lower bound and relatively complemented lattice, and established relation among them. We also studied some other properties of these concepts and we have showed that two lattices A and B are relatively complemented if and only if the cross product of two lattices A and B is relatively complemented. Chapter three: We have discussed Boolean algebra, Boolean lattice and Boolean function. Let (A, ˄, ˅, ', 0, 1) be a Boolean algebra. Expressions involving members of A and the operations ˄, ˅ and complementation are called Boolean expressions or Boolean polynomials. For example, x ˅ y', x, x ˄ 0 are etc. all Boolean expressions. Any function specifying these Boolean expressions is called a Boolean function. Thus if/(x,y) =X ˄ y then f is the Boolean function and x ˄ y is the Boolean expressions (or value of the function f). Since it is normally the functional value (and not the function) that we are interested in, we call these expressions the Boolean function. We will denote least and greatest elements of a Boolean algebra by 0 and 1 respectively. In fact, most of the times we will confine ourselves to Boolean algebras that contain only these two elements. We also discus in this chapter Disjunctive Normal form (DN form), Conjunctive Normal form (CN form), Length and Cover. A Boolean function is said to be in DN form in n variables x1, x2, …… xn if it can be written as join of terms of the type f1(x1) ˄ f2 (x2)A ........ ˄ fn (xn ) where fi(xi ) = xi, or x’i for all i =1,2,3,…… ,n and no two terms are same. Also 1 and 0 are said to be in DN form. We also prove them theorem: 'Every Boolean function can be put in DN form'. Here we give several results on DN form, CN form, Homomorphisom, Iso-morphisom and Indomorphisom. Chapter four : In this chapter we have studied series combination, parallel combination, don't care condition and Bridge circuits. By a switch we mean a contact or a device in an electric circuit which lets the current to flow through the circuit. The switch can assume two states 'closed 'or 'open '(ON or OFF). In the first case the current flows and in the second the current does not flow. We will use a,b,c, . . ..... .....x,y,z........etc. to denote switches in a circuit. Two switches a,b are said to be connected 'in series' if the current can pass only when both are in closed state and current does not flow if any one or both are open. Two switches a, b, are said to be connected 'in parallel' if current flows when any one or both are closed and current does not pass when both are open. In this chapter we also solve some circuit problems.Item A Study on Distributive Nearlattices(Rajshahi University, Rajshahi, Bangladesh, 1994-08) Rahman, Md. Bazlar; Noor, Prof. Dr. A.S.A.This thesis studies the nature of distributive nearlattices. By a nearlattice S we will always mean a (lower) semilattice which has the property that any two elements possessing a common upper bound, have a supremum, Cornish and Hickman in their paper [14], referred this property as the upper bound property, and a semilattice of this nature as a semilattice with the upper bound property. Cornish and Noor in [15] preferred to call these semilattices as nearlattices as the behaviour of such a semilattice is closer to that of a lattice than an ordiary semilattice. In this thesis we give several results on nearlattices which certainly extend and generalize many results in lattice theory. In chapter 1 we discuss ideals, congruences and other results which are basic to this thesis. We include some characterizations of distributive and modular nearlattices. We generalize the separation properties given by M. H. Stone for distributive lattices. We also show that the set of prime ideals of a nearlattice S is unordered if and only if S is semiboolean. Chapter 2 discusses the skeletal congruences of a distributive nearlattice. Skeletal congruences on distributive lattices have been studied extensively by Cornish in [11]. Here we extend several results of Cornish for nearlattices. We also introduce the notion of disjutive nearlattices. A distributive nearlattice S with 0 is called disjunctive if for 0 ≤ a < b there is an element x ϵ S such that x ˄ a = 0 and 0 < x ≤ b. Then we give several characterizations of disjunctive nearlattices and semiboolean algebras using skeletal congruences. Finally we show that a distributive naerlattice is semiboolean if and only if θ -----> ker θ is lattice isomorphism of Sc(S) onto KSc(S) whose inverse is the map J´ ---> θ (J). In chapter 3, we discuss on normal and n-normal nearlattices. Normal lattices have been studied by several authors including Cornish [8] and Monteiro [34]; while n-normal lattices have been studied by Cornish [9] and Davey [16]. In proving some of the results we have used Principle of Localization, which is an extension of lecture note of Dr. Noor on localization. This technique is very interesting and quite different from those of the previous authors. Chapter 4 studies the multiplier extension (meet translation) of a distributive nearlattjce. Previously multipliers on semilattices and lattices have been studied by several authors e.g, Szasz and Szendrje [54,55,56] Kolibiar [29],Cornjsh [101 and Niemenen [37] on a latice. In a more recent paper, Noor and Cornjsh in [39] studied them on nearlatticee. Here we extend some of their work. We also give a categorjcai result, where we see that the multiplier extension has a functorial character which is entirely different from that of the Lattice Theory, c.f. Cornish [10, theorem 2.41. In section 2 of this chapter we discuss multipliers on sectionally pseudocomplemented distributive nearlattices which are sectionally in B՛n, -1 ≤ n ≤ Ꞷ and generalize a number of results of [10]. We show that S is sectionally in Bn if and only if M(S), the lattice of multipliers is in Bn. Finally we show that for 1 ≤ n < Ꞷ, above conditions are also equivalent to the condition that S is sectionally pseudocomplemented and for any n+1 minimal prime ideals P1,P2,. ........... ,Pn+1, P1 V P2 V ........... V Pn+1 = S.