University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Damage model for cyclic loading of concrete

Abstract: A damage model for monotonic and cyclic behavior of concrete is developed. The model recognizes the tortuous nature of cracks in compression, which affects the flexibility of the material in a direction coinciding with the average plane of the cracks. An elastic potential is introduced in terms of the principal stresses and a compliance tensor dependent on the accumulated damage. Damage evolution is obtained using a loading surface and bounding surface, defined in terms of the thermodynamic force conjugates of the damage variables. The damage growth during a series of unaxial compression and cyclic tests is inferred from the amplitude attenuation of ultrasonic waveforms transmitted laterally through the specimen while the tests are in progress. The behavior of concrete under compression, tension, biaxial loading and cycling, and damage growth under both monotonic and cyclic loading are found to be predicted well by the proposed theory.

Tsunami on 26 december 2004: spatial distribution of tsunami height and the extent of inundation in sri lanka

Abstract: This paper examines the impact of the massive tsunami of 26 December 2004 on Sri Lanka by tracing the tsunami height, the extent of inundation and the level of damage along the affected coastal belt. The results of an extensive field survey that was carried out in the east, south and west coasts to record the evidence of water levels left behind by the tsunami clearly indicate nonuniform spatial distribution of inundation along the affected coastline of the country. The tsunami inundation had been significantly greater for most parts of the east and the south-east coastal areas than the south, south-west and the west coasts of Sri Lanka. The results also indicate the possible influence of the coastal geomorphology on the extent of inundation. On the other hand, the measurements suggest maximum tsunami heights of 3 m – 7 m along the east coast, 3 m – 11 m on the south coast, and 1.5 m – 6 m on the west coast.

Clinicopathological analysis of osteosarcoma of jaw bones.

Abstract: Objectives: To identify clinicopathological characteristics and prognosis of osteosarcoma of the jaw bones (JOS) and to compare the data with results of similar studies. To study the effectiveness of different treatment modalities currently available for this malignancy. Subjects and methods: Nineteen cases of JOS diagnosed from 1993 to 2003 were retrieved from the departmental archives. These were categorized into histopathological subtypes and graded according to the severity of the malignancies and the data analyzed. Fourteen cases were followed up and the success rate with different treatment modalities assessed. Results: The mean age for JOS was 34.1 years. There were 11 mandibular lesions and eight maxillary lesions. Osteoblastic variant (53%) was the commonest histopathological subtype. High grade (grades III and IV) was more prevalent. All 14 followed up patients underwent surgical excision – five with adjuvant radiotherapy and six with adjuvant chemotherapy. Local recurrence was the commonest complication. Nine of the 14 were surviving with a survival rate of 64.2% for a median follow-up period of 5.25 years. Conclusions: JOS is a distinct group of lesions with a better prognosis if diagnosed and treated early. It does not show any ethnic variability. Existing histopathological typing and grading may not indicate the prognosis of JOS. Adjuvant chemotherapy is a better treatment modality than adjuvant radiotherapy.

Geographical distribution of chronic kidney disease of unknown origin in North Central Region of Sri Lanka

Abstract: Objectives In early nineties investigators noticed an alarmingly high incidence of an apparently new form of chronic kidney disease of unknown aetiology (CKD-U) in some parts of Sri Lanka. The aim of the study was to investigate the geographical distribution of CKD-U using GIS and GPS mapping. Methods Community based information was collected from 11,630 patients for GIS mapping using ARC 9.2 software. Based on GIS mapping, two locations were selected for GPS mapping to locate the households of 863 CKD-U patients with reference to reservoirs, irrigation canals and the topography of the areas. Results GIS mapping indicated five high prevalence areas of CKD-U. Communities who consumed water from natural springs showed a low prevalence of the disease. GPS mapping showed that most of the affected villages were located below the reservoirs and canals with stagnant irrigated water. Conclusion Epidemiological data on geographical distribution infers that while older foci of CKD-U are persisting, there is an emergence of new foci with time. The location of the affected villages below the level of the reservoirs/canals may indicate the possibility of draining of irrigated water to the shallow wells of the households, which is the source of drinking water. DOI: http://dx.doi.org/10.4038/cmj.v58i1.5356 Ceylon Medical Journal 2013; 58 : 6-10