Research Papers - Department of Civil Engineering

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Author: search.filters.author.Perera, S. V. THas files: Yes

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Now showing 1 - 10 of 11
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    PublicationOpen Access
    Postharvest ripening and respiration of chili
    (University Of Ruhuna, 2004) Chaturani, G. D. G; Wilson, S; Perera, S. V. T; Hettiarachchi, M. P
    Effect o f exogenous ethylene application on postharvest ripening and respiratory pattern o f chilli (Capsicum annum Var.MI-2) harvested at different stages o f maturity was examined. Chillies harvested at mature green and colour break stages were used fo r the ripening study. Pods were allowed to ripen at ambient conditions (32 ± 2 °C and 37% RH) with 0, 100, 200, 300, and 400ppm ethylene concentrations. Observations were made on colour development and weight o f red ripe pods during storage period. Ethylene treatment had no significant effect on colour development o f chilli harvested at both stages o f maturity. Fruits harvested at different stages o f maturity ranging from light green to fu ll red were usedfor the respiration study at 12.2 °C and 83 % RH in a closed system. Respiration rates o f chilli from light green to fu ll red stage ranged between 12.7-24.2 mgCO/kg/h. The rate o f respiration was low at light green stage and increased with maturity reaching a peak (24.2 mgCO/kg/h) at colour break stage. Respiration rate decreased with fru it ripening and increased with development o f full red colour. The internal ethylene concentration o f pods was ranged between 3.2-4.3 ppm. However, there was no ethylene peak observed with the maturity.
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    PublicationOpen Access
    EFFECT OF PORCELAIN WASTE AS A FINE AGGREGATE ON THE MECHANICAL PROPERTIES OF CONCRETE
    (University of Peradeniya, 2019-08-13) Kobbekaduwa, K. W. D; Perera, S. V. T
    The demand for concrete keeps significantly increasing worldwide throughout the past few years period. The exponential development rate and construction processes on developing infrastructure facilities all over the globe has resulted this situation. As an outcome of that, the excessive production of concrete has led to several environmental impacts all around the world. This study investigated the suitability of crushed porcelain waste as a replacement for fine aggregates by analysing the strength gains and other mechanical properties depending on the replaced proportions. Porcelain Waste Fine Aggregate (PWFA) which is a low water absorbing material was used in replacing conventional fine aggregates in the proportions of 25%, 50%, 75%, 85% and 100% for the concrete of Grade 30. It was found that the most suitable and economical replacement proportion of PWFA is the 75% mix as it comprised a 28-day compressive strength of 54.31 MPa which is 50% greater than the compressive strength of control mixture. Due to the higher strength, the 75% PWFA Grade 30 mix can be implemented as Grade 45 concrete which can save up to 10% of the cost. The partial replacement of sand using PWFA significantly improved the performance of concrete while addressing several environmental and economic issues related to concrete industry.
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    PublicationOpen Access
    Shear Capacity of Reinforced High-Strength Concrete Beams without Web Reinforcement
    (The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), 2013-09-11) Perera, S. V. T; Mutsuyoshi, H
    Three series of reinforced concrete (RC) beams without web reinforcement were tested to determine their diagonal cracking shear strengths and ultimate shear capacities. Within each series, the shear span to depth ratio was held constant at 3.0, 3.5, or 4.0 while the characteristic compressive strength of concrete was varied from 36 to 194 MPa in otherwise identical specimens. Test results indicated that the ratio of uniaxial compressive strength to tensile strength of the concrete was proportional to concrete brittleness. According to the JSCE code and the ACI code, the shear strength of RC beams increases with increasing concrete strength. However, test results showed that, the JSCE code and the ACI code for predicting shear strength were not safe.
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    PublicationOpen Access
    Development of a Formula to Quantity Emlsslons Generated from Dlesel Vehicles in Sri Lanka
    (ACEPS-2017, 2017) Konara, K. M. T. N; Samarasekara, G. N; Chaminda, G. G. T; Dissanayaka, A. W; Perera, S. V. T
    Using the combination of optical properties of diesel exhaust and Beer Lambart law, particulate concentration was derved. Major component of the particulate matter of diesel exhaust was elė carbon which was derived from the optical properties of diesel exhaust. Characteriza emission composition was done through literature. According to the Spaciate 4.0 databa state environmental agency, characterization of diesel emission was finalized. Spaciate 4 the diesel exhaust is a primary combination of Organic carbon (31.80%), Elemental ca Sulphate (0, 67%), Nitrate (0.19%) and others including metallic components and etc.(6 that, a balanced chemical equation was formed for the incomplete combustion of the di air. Calculation of CO2, CO and PM was derived based on the stoichiometric ratio of the bäjä chemical equation.
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    PublicationOpen Access
    Development of GFRP and UHF composite girders
    (The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), 2013-09-13) Wijayawardane, I. S. K; Mutsuyoshi, H; Perera, S. V. T; KANAYA, Y
    In this paper, the development of a composite girder using glass fiber reinforced polymer (GFRP), ultra high strength fiber reinforced concrete (UHF) and fiber reinforced polymer (FRP) bolts is illustrated. Experiments were carried out previously with steel bolts which connect the UHF blocks to the GFRP beam. Because of the corrosion of the steel bolts, the life span of the composite girder is reduced. Therefore, in this test series FRP bolts were used. Four point bending tests were conducted for a number of I-beams of same cross-sectional dimensions having epoxy bonded and FRP bolted UHF blocks at the top flange. In order to check the performance of the FRP bolt connections between FRP beam and UHF blocks, different bolt diameters and bolt spacing were considered. Behavior of the strain variation of top flange was compared in order to check the utilization of the ultimate tensile strain of GFRP. In fact, the experiment results show that the failure load of the composite I-beam has reduced compared to similar steel bolt connection. However, failure load similar to steel bolt connection can be achieved with many FRP bolts. Therefore, the FRP bolts can be used in UHF and GFRP composite girder which increase the durability of the girder.
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    PublicationOpen Access
    Impact of change in head and neck position on ultrasound localisation of the cricothyroid membrane: an observational study
    (http://www.anaesthesiacorrespondence.com, 2019-01) Dixit, A; Ramaswamy, K. K; Perera, S. V. T; Sukumar, V; Frerk, C
    The ideal position for performing surgical cricothyroidotomy is with full neck extension. Some authors have recommended marking the cricothyroid membrane before general anaesthesia, typically with the patient's head and neck in a neutral position. The primary aim of this observational study was to determine whether skin marks made over the centre of the cricothyroid membrane with the head and neck in the neutral position moved outside the boundaries of the membrane when the neck was subsequently extended. The secondary aim was to assess changes in the height of the cricothyroid membrane between the neutral and extended positions. Twenty-two volunteers completed the study. With the head and neck in the neutral position, the distance between the upper and lower borders (‘height’) of the cricothyroid membrane was measured by a radiologist using ultrasound. The skin was marked over the mid-point of the membrane. The subject then maximally extended the neck, and the measurements and marking were repeated. The skin marking over the centre point of the cricothyroid membrane moved by median (IQR [range]) 5 (4–6 [0–10]) mm when the head and neck were moved from a neutral to a fully extended position. The initial skin mark moved to lie outside the boundary of the cricothyroid membrane in 12 of 22 subjects after extending the neck. The height of the cricothyroid membrane increased by 30% with the neck extended. We recommend that marking the skin in preparation for cricothyroidotomy should be performed with the neck extended, not with the head and neck in the neutral position as previously suggested.
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    PublicationOpen Access
    Visibility of pharyngeal structures as a predictor of difficult intubation
    (Blackwell Publishing Ltd, 1987-10) Charters, P; Perera, S. V. T; Horton, W. A
    Visibility of pharyngeal structures as a predictor of difficult intubation Page 1 Correspondence 1115 Visibility of pharyngeal structures as a predictor of difficult intubation We would like to comment on the study by Samsoon and Young (Anuesihesh 1987; 42: 487-90) since we also have experience with the test which forms the basis of their report. Mallampati’s test scores the visibility of pharyngcal structures (faucial pillars, soft palate and uvula) in an attempt to predict difficult tracheal intubation. Three of us used this test as part of a pre-operative asscssmcnt in a study about tracheal intubation. Sainsoon and Young did not make it clear in their paper hut thcy did not make the assessment in the way described by Mallampati. We also chosc to examine our patients with ‘the head in the neutral position’ and the observer sitting ‘opposite at eye level’. We graded paticiits class 1 to 3 as originally described because Mallampati …
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    PublicationEmbargo
    Shear Behavior of Reinforced High-Strength Concrete Beams
    (Institute publication policies, 2013-01-01) Perera, S. V. T; Mutsuyoshi, H
    This paper describes the shear behavior of reinforced high-strength concrete (RHSC) beams (fc′ > 100 MPa [14,500 psi]) without web reinforcement. The use of high-strength concrete (HSC) has led to some concerns about its shear strength because of its brittleness, smooth fracture surface, and high early-age shrinkage. Test results indicated that the ratio of uniaxial compressive strength to tensile strength (the ductility number) of the concrete relative to that of the aggregate governs the shear strength of HSC. When the ductility number of the concrete coincided with that of the aggregate, the shear strength remained constant, irrespective of concrete strength. When the ductility number of the concrete was higher than that of the aggregate, however, shear strength started to decrease due to the smooth fracture surface and brittleness. By introducing earlyage shrinkage and a suitable aggregate size, the modified compression field theory (MCFT) was found to accurately predict the shear strength of RHSC beams.
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    PublicationOpen Access
    Impact of change in head and neck position on ultrasound localisation of the cricothyroid membrane: an observational study
    (Wiley Online Library, 2019-01) Dixit, A; Ramaswamy, K. K; Perera, S. V. T; Sukumar, V; Frerk, C
    The ideal position for performing surgical cricothyroidotomy is with full neck extension. Some authors haverecommended marking the cricothyroid membrane before general anaesthesia, typically with the patient’shead and neck in a neutral position. The primary aim of this observational study was to determine whether skinmarks made over the centre of the cricothyroid membrane with the head and neck in the neutral position movedoutside the boundaries of the membrane when the neck was subsequently extended. The secondary aim was toassess changes in the height of the cricothyroid membrane between the neutral and extended positions.Twenty-two volunteers completed the study. With the head and neck in the neutral position, the distancebetween the upper and lower borders (‘height’) of the cricothyroid membrane was measured by a radiologistusing ultrasound. The skin was marked over the mid-point of the membrane. The subject then maximallyextended the neck, and the measurements and marking were repeated. The skin marking over the centre pointof the cricothyroid membrane moved by median (IQR [range]) 5 (4–6[0–10]) mm when the head and neck weremoved from a neutral to a fully extended position. The initial skin mark moved to lie outside the boundary of thecricothyroid membrane in 12 of 22 subjects after extending the neck. The height of the cricothyroid membraneincreased by 30% with the neck extended. We recommend that marking the skin in preparation forcricothyroidotomy should be performed with the neck extended, not with the head and neck in the neutralposition as previously suggested.
  • Thumbnail Image
    PublicationOpen Access
    Visibility of pharyngeal structures as a predictor of difficult intubation
    (Blackwell Publishing Ltd, 1987-10) Charters, P; Perera, S. V. T; Horton, W. A
    Visibility of pharyngeal structures as a predictor of difficult intubation Page 1 Correspondence 1115 Visibility of pharyngeal structures as a predictor of difficult intubation We would like to comment on the study by Samsoon and Young (Anuesihesh 1987; 42: 487-90) since we also have experience with the test which forms the basis of their report. Mallampati’s test scores the visibility of pharyngcal structures (faucial pillars, soft palate and uvula) in an attempt to predict difficult tracheal intubation. Three of us used this test as part of a pre-operative asscssmcnt in a study about tracheal intubation. Sainsoon and Young did not make it clear in their paper hut thcy did not make the assessment in the way described by Mallampati. We also chosc to examine our patients with ‘the head in the neutral position’ and the observer sitting ‘opposite at eye level’. We graded paticiits class 1 to 3 as originally described because Mallampati