Service Limit Criteria for Deflection and Cracking in Partially Prestressed Beams

This thesis has been concerned with the primary objective of studying the serviceability behavior of partially prestressed concrete beams. Seven simply supported rectangular beams were tested on an effective span of 2.745 m subjected to two third point loadings. The variables were the amount of prestressing wires and ordinary reinforcement steel. The effect of bond was also investigated. Four beams were fully bonded by using pressurised grouting while three other beams were tested unbonded. Crack widths and deflections were recorded at various loadings, and crack propagations observed. The results obtained were compared with theoretical values proposed by various authors. Results were also compared with the service limit criteria for cracking and deflection according to the British Standards code of practice, CP 110:1972. It was observed that the service limit criteria for cracking and deflection as set out by the code are too conservative for rectangular beams tested. It was found that the existing theory greatly underestimates the ultimate as well as service load carrying capacity and overestimates crack widths of partially prestressed concrete beams. It was also found that the nature of bonding has a great influence on crack widths and deflections. Bonded beams greatly improve on serviceability by having increased load carrying capacity and reduced crack width

The application of remote sensing in open moorland soil erosion studies: a case study of Glaisdale moor, northern England

The potential of remote sensing in upland soil erosion studies has been examined on Glaisdale Moor, North Yorkshire Moors. The study considers four different remote sensing sources, viz. sequential air photographs, ground radiometry, Landsat Thematic Mapper (TM) and SPOT simulation. Sequential air photographs have been interpreted in order to elucidate the land use/land cover changes and the drainage development and associated erosion problems in the region. A series of statistical analyses were employed in an effort to establish the relationships between the different spectral variables and the soil/ground variables. Attempts have also been made to evaluate the spectral separability performance of the Ground radiometer, the Landsat TM and the SPOT simulation wave bands. The Landsat TM and the SPOT simulation imagery have been further analysed in order to gather information about the best band and band combinations that would be required to optimize the discrimination of moorland surface types including eroded areas. Digital image processing of the Landsat TM and the SPOT simulation subscene for Glaisdale Moor was performed using the DIAD image processing system. The land use/land cover classification information derived from the air photographs, the Landsat TM and the SPOT simulation, has been used as an input into a soil loss prediction model (USLE) to predict the soil erosion rate of the study area. Of the various remote sensing systems used, air photographs and TM data proved the most useful in this area

Conduction of reparative dentin: A pulp protecting approach by indirect pulp capping in deep carious lesion with biodentine

This case report represents, the treatment of deep carious lesion in a male was done by using indirect pulp capping with biodentine. The clinical and radiological outcomes were evaluated. The patient was presented with mild to moderate sensitivity on thermal (cold) stimulation and discomfort associated with eating in the left mandibular first molar. The clinicoradiographical examination revealed a distoocclusal carious lesion, very close to the pulp, absence of radiolucencies in the periapical region and no periodontal space widening. Pulp sensitivity was confirmed by thermal pulp vitality test. Indirect pulp capping treatment was performed with biodentine. Following 6 months of the treatment, the clinical symptoms were resolved and a calcific bridge was found at the dentin over the pulp and biodentine interface that was indicative the evidence of reparative dentin formation

Palato-gingival groove: An innocuous culprit for endo-perio lesion

This case report represents the clinical management of tooth with palato-gingival groove in a right maxillary lateral incisor with endo-perio lesion leading to dento-alveolar abscess and sinus tract. The right maxillary lateral incisor was examined clinico-radiographically. On clinical examination, the offending tooth revealed localized swelling and an intraoral draining sinus pointing on the labial gingiva without any evidence of caries, discoloration and trauma. The palatal surface of lateral incisor showed a groove with mild calculus embedded in it. The radiographic examination revealed periapical radiolucency. This case provides an evidence of morphological defect of tooth. Complete clinical and radiological examination and adequate knowledge of such morphological/ developmental defects of teeth are necessary for recognition and identification especially because of their diagnostic complexity and further consequences.

Five Root Canals for a Maxillary First Molar Tooth A Case Report

This case report represents assessment and management of a maxillary left first molar tooth containing five root canals by endodontic treatment. In this case Mesiobuccal 2 (MB2), Mesiopalatal (MP) and Distobuccal (DB) canals were missed as well as very poor obturation at palatal and mesiobuccal1(MB1) canal during previous treatment history. Three mesiobuccal (MB1, MB2, and MP), DB and palatal canals were identified and endodontic retreatment was done followed by final restoration. This case provides an evidence of variations in the root canals of the mesiobuccal root of maxillary first molar tooth. Complete clinical and radiographic examination and adequate knowledge of the morphology of this kind of teeth is necessary for successful clinical outcome.DOI: http://dx.doi.org/10.3329/bsmmuj.v5i1.11026 BSMMU J 2012; 5(1):61-64

Access to broadband internet and labour force outcomes: a case study of the Western Downs Region, Queensland

This paper examines the causal effect of household access to broadband Internet on individuals’ labour market outcomes in an Australian rural and regional context. This study uses the survey data of 391 households randomly selected from the Western Downs Region of Queensland, Australia, and employs the propensity score matching technique to make causal inferences. This study also controls selection bias issues – an aspect which has been overlooked in previous studies. This study found that the causal effect of household access to broadband Internet on individuals’ labour force outcomes is not statistically significant. This finding can add value to our knowledge of the causal relationship between broadband access and labour force participation. As the rollout of a high-speed broadband network in rural and regional Australia is currently underway, the finding can be considered a benchmark for subsequent assessment of the effects of such infrastructure development on socio-economic outcomes

Management of Tooth Resorption by Using Calcium Hydroxide: A Case Report

In this case report, the treatment of internal root resorption in a 24 years-old male was done by using nonsurgical root canal therapy and the clinical outcome was evaluated. Both the maxillary central incisors were examined clinico-radiographically. On clinical examination, the maxillary incisors were found discolored. Radiographic examination revealed a punched-out radiolucent lesion on the cervical area of pulpal canal of both of the teeth and periradicular radiolucency was also evident. Conservative non-surgical root canal treatment was performed with long term calcium-hydroxide therapy. Following eight months of the treatment, the resorption process was stopped and a calcific bridge was formed at the apex of the roots indicated the evidence of recalcification. Conventional root canal obturation method was implied followed by clinical and radiological evaluation for next two years.DOI: http://dx.doi.org/10.3329/bsmmuj.v5i1.11029 BSMMU J 2012; 5(1):72-75

Price Behaviour of Major Cereal Crops in Bangladesh

The key concern of this research is to analyse the extent of the seasonal price fluctuation and spatial price relationship of major cereal crops viz., Boro paddy and wheat in different markets in Bangladesh. This study was entirely based on secondary data from the period of 1986-87 to 2009-10 from different sources. In estimating seasonal price fluctuation of selected crops it was found that crops prices fluctuated in different months within the year. The difference between peak and trough prices was higher for Boro paddy than wheat. Coefficient of variation was also higher for Boro paddy than wheat but these figures are decreasing gradually. The results of empirical evaluation of spatial price linkage through Engle-Granger co-integration method among regional selected markets of Bangladesh using harvest price of Boro paddy and wheat indicate that these markets were well integrated. That means, information about price changes are fully and instantaneously delivered to the other markets in Bangladesh. Price analysis and formation of policy at the aggregate level will be pertinent for policy implementation. Keywords: Price behaviour, Cereal crops, Market integration, Unit root, Engle-Grange

Input switched closed-loop single phase SEPIC controlled rectifier with improved performances

DC power supply has become the driving source for some essential modern applications. Thereby, DC power conditioning has become a significant issue for engineers. Typically used rectifiers associated with a bridge structure is nonlinear in nature. Thereby, the current at input side of the rectifier contains harmonics, which also flow through the power line. The presence of harmonics causes several interruptions and reduce power quality. In this regard, a new close loop SEPIC controlled rectifier is proposed in this paper. The conventional scheme is arranged with a rectifier connected to a DC-DC converter, which is an open loop system. Consequently, such system cannot regulate voltage at load varying condition. The proposed SEPIC controlled rectifier can regulate voltage under load varying condition for a wide range. Additionally, the performance in terms of total harmonic distortion (THD) of input current and power factor at AC side are also within satisfactory range for the closed loop configuration. The controlled rectifier has four operating phases associated with switching states and input voltage polarity. The close loop configuration also incorporates a current and a voltage loop at the feedback path. The comparative studies have been performed among the proposed closed loop construction, the open-loop structure as well as the conventional construction. The effectiveness of the proposed controlled rectifier is verified in terms of THD and input power factor considering the results obtained from simulation

Evaluation of clinical and radiological outcomes of mineral trioxide aggregate and calcium hydroxide as indirect pulp capping agents in the treatment of deep carious lesion of permanent teeth

The maintenance of pulp vitality and conduction of reparative dentin can be possible by indirect pulp capping with mineral trioxide aggregate (MTA) and calcium hydroxide as pulp capping agents. The objective of the study is to assess the clinical and radiological outcomes of MTA and calcium hydroxide as indirect pulp capping agents in deep carious lesions of permanent teeth. The present study included 50 permanent teeth having deep carious lesions with reversible pulp status were selected and then randomly divided into two groups of 25 teeth in a group. Standard indirect pulp capping procedures were followed. Patients were recalled at 3, 6 and 12 months interval to assess postoperative pain, the vitality of the pulp and formation of reparative dentin. In all observation periods, MTA showed more capable of reducing pain and maintain pulp vitality which was statistically significant than that of calcium hydroxide. At 12 months observation period, 24 teeth (96%) of MTA and 19 teeth (76%) of calcium hydroxide showed reparative dentin formation. It can be concluded that MTA is more effective than that of calcium hydroxide.