http://ir.lib.seu.ac.lk/handle/123456789/6907 2023 2026-04-02T09:38:03Z http://ir.lib.seu.ac.lk/handle/123456789/6913 Title: The Impacts of Critical Construction Supervisory Competencies on the Efficiency, Productivity and Sustainability of Road Construction Operations in Sri Lanka Authors: Manoharan, Kesavan; Dissanayake, Pujitha; Pathirana, Chintha; Deegahawature, Dharsana; Silva, Renuka Abstract: Supervision practices play a crucial role in acting as a bridge between labour and organisations in construction. According to sources, the progress of construction projects is negatively impacted by the inadequate competencies of construction supervisors in developing nations like Sri Lanka. This study aims to pinpoint the critical supervisory competencies that affect the efficiency, productivity and sustainability of road construction operations. Qualitative and quantitative methods were applied to determine the essential supervisory competencies of the construction industry. To analyse the necessary actions, industry-expert discussions were held using problem-focused communication approaches. In total, 17 cognitive elements and 25 skills/abilities of construction supervisors were identified as being crucial according to their impact values, with the topranking cognitive domains for construction supervisors being basic concepts of structures and performance evaluation of labour skills, followed by their manual skills/abilities in labour management and communication. A list of anticipated key competency outcomes was presented for assisting the development processes of new productive construction supervisory training components. Pertinent statistical analysis results and the industry consultation outcomes assured the validity and dependability of the overall findings. The results demonstrate how the significant construction supervisory competencies impact the efficiency and sustainability of road construction operations with the necessary quantitative measurements, and these results will be highly useful to the industry sector skill enhancement authorities/boards as they update their training development practices intending to enhance the sustainability and work culture of construction project operations. The study findings have greatly influenced how the industry re-skills and upskills workers in terms of supervision, work culture, efficiency, sustainability and productivity management. While Sri Lankan road construction projects were the study’s primary focus, some of the findings will also be tested in situations similar to those in other developing construction industries worldwide. 2023-06-30T00:00:00Z http://ir.lib.seu.ac.lk/handle/123456789/6912 Title: Optimizations of antioxidants-rich herbal tea formulation from selected medicinal plants for the enhancement of Psidium guajava tea Authors: Lilachjini, S.; Haroon, M. Haniffa Abstract: Herbal teas are simple, effective, inexpensive, drugfree, and caffeine-free ways to enjoy the flavor and benefits of herbs and spices, which are commonly consumed by people since they are natural, harmless, and can assist in treating or controlling various therapeutic illnesses. The purpose of this study was to develop guava leaf-based herbal tea with a combination of supporting and activating herbs such as Cinnamomum zeylanicum (cinnamon) leaf and bark, Senna auriculata (avaram senna) flower, Gymnema sylvestre (gurmar), Ocimum tenuiflorum(holy basil) leaf, and Citrus limon (lemon) leaf in order to improve guava tea. Herbal teas were prepared using nine various combinations of the above-mentioned plant materials along with guava tea for comparative purposes. The extraction of tea was done by infusing tea bags, and phytochemicals were screened with a standard procedure. Total polyphenolic content (TPC) and total flavonoid content (TFC) were determined using the Folin-Ciocalteu approach and the aluminum chloride spectrophotometric method, respectively. Total antioxidant capacity was determined by the ferric reducing antioxidant power (FRAP) assay, while radical scavenging activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The toxicity of developed tea bags was assessed using a brine shrimp micro-well cytotoxicity assay. According to the findings, all of the prepared herbal teas and guava tea are rich in essential phytochemicals. Moreover, the combination of guava leaf, cinnamon bark, cinnamon leaf, avaram senna flower, gurmar leaf, holy basil leaf, and lemon leaf (35:20:1:1:1:1:1) exhibited the highest TPC (2027.12 mg GAE/ml) and antioxidant capacity (82.33 mg ascorbic acid eq/ml). During sensory evaluation, this composition was most preferred to guava tea by the semi-trained panel, and it showed nontoxicity to brine shrimp (LC50 values higher than 1000 mg/L). In conclusion, even though guava tea has already been developed and proven to have anti-diabetic and antioxidant properties, the herbal tea formulation from seven medicinal plants showed the greatest preference due to the highest TPC and highest antioxidant capacity. Further studies are needed to determine the antidiabetic properties of developed herbal teas and compare the anti-diabetic properties of guava tea. 2023-06-30T00:00:00Z http://ir.lib.seu.ac.lk/handle/123456789/6911 Title: Exploring the potential use of Moringa olifera Lam and Azadirachta indica additives in Orchid tissue culture Authors: Rathnayaka, R. M. C. U; Herath, H. M. I; Mubarak, A. N. M; Nashath, M. N. F Abstract: This study was conducted in the Floriculture Research and Development Unit at the Royal Botanical Gardens, Peradeniya to explore the potential of Moringa olifera Lam. (Moringa) and Azadiracta indica (Neem) organic supplements for promoting Orchid invitro culture of Dendrobium spp . The Knudson C (KnC) basal media was prepared by additionally supplemented with either 5g/l, 10g/l and 15g/l of moringa powder, moringa leaf extract and neem leaf extract separately. The experiment was laid out in completely randomized design with 10 treatments having 10 replicates. One month after explant incubation, the number of leaves, shoots and roots per plantlets and shoot length were recorded. According to the results, different treatments had significantly affected the tested parameters (p<0.05). Both moringa and neem leaf extracts gave improved responses compared to moringa powder. ¼ KnC+15g/l of moringa leaf extract performed well in terms of producing increased number of leaves and roots per plantlet, whereas full KnC+5g/l of moringa leaf extract resulted the highest number of shoots per plantlet (3.5). On the contrary, neem leaf extracts (5g/l, 10g/l and 15g/l) increased the shoot length of orchid explants and produced significantly higher number of roots per plantlet. Hence, moringa and neem leaf extracts can be used to develop a simple and cost effective culture media for promoting orchid tissue culture. 2023-06-30T00:00:00Z http://ir.lib.seu.ac.lk/handle/123456789/6910 Title: Effect of Yaramila complex fertilizer on growth and yield of Cucumber (Cucumis sativus L.) Authors: B. Wasala, W. M. A. Namal; H. Seran, Thayamini; Lakmali, K. N. D. Abstract: This study was conducted to evaluate the effect of Yaramila complex fertilizer on the growth and yield of cucumber (Cucumis sativus L.). The experiment was laid out in Randomized Complete Block Design (RCBD) with six treatments (T1-T6) in nine replications. The Yaramila complex fertilizer (12:11:18 NPK + 3MgO + 8S) was applied at different rates as basal (0-4 g per plant) and top dressing (4-8 g per plant), whereas treatments were T1 (0,4), T2 (0,8), T3 (2,4), T4 (2,8), T5 (4,4) and T6 (4,8). The results revealed that the application of Yaramila fertilizer had a significant influence on the vine length, number of leaves, the total number of fruits, and fresh weight of fruits per plant, as well as the dry weight of crop residue among the treatments. At 5% significant level, the vine length in T4 (2 g basal and 8 g top dressing) (37.12 cm) was significantly longer than that (27.75 cm) in T5 (4 g basal and 4 g top dressing), which had a shorter vine length compared to other treatments at 4th WAP. The number of leaves was high (7.3) in T6 (4 g basal and 8 g top dressing), whereas the number of leaves was low (4.9) in T2 (0 g basal and 8 g top dressing) at 2 nd WAP. Yaramila fertilizer application significantly (P=0.0001) influenced the total number of harvested fruits per plant. There were no remarkable differences in fruit diameter and fruit length between the treatments at P=0.05. Fruit length ranged from 14.06 cm (T1 as a control: 0 g basal and 4 g top dressing) to 17.33 cm (T4: 2 g basal and 8 g top dressing). There was a significant difference (P=0.0012) in harvested fruit weight per plant among the treatments. The highest mean value of cumulative fruit yield was obtained in T5 (14,968.89 kg/ha), and the least value was observed in T3 (7,857.78 kg/ha). Yaramila fertilizer 4 g per plant as basal application and 4 g per plant as a top dressing (2 g at 2 weeks and 2 g at 4 weeks) [T5 treatment] could be used in cucumber cultivation to obtain high fruit yield. 2023-06-30T00:00:00Z