Experimental Study of the Fluid Drag on a Torus at Low Reynolds Number.

Measurements are presented for the drag on a torus moving along its axis of rotational symmetry at low Reynolds number. If D is the outside diameter of the torus, and d is the thickness in the axial direction, then the measurements cover the range s(,o) = 1 (the closed torus) to s(,o) = 135, where s(,o) (TBOND) (D/d) - 1. The effect of a coaxial cylindrical boundary (diameter H) is taken into account by an empirical correlation. The values of drag obtained by extrapolating to a fluid of infinite extent are in good agreement with the exact solution obtained by Majumdar and O\u27Neill. When (pi)d(s(,o))(\u27 1/2) \u3c\u3c H, the empirical boundary correlation is consistent with the result of Brenner for small particles. Measurements with outer boundaries of square and circular cross-section indicate that the relative effect of the two boundary shapes on the drag is the same for the torus as that found by Happel and Bart for a sphere. Empirical results are presented for the case in which the torus is strongly influenced by a coaxial cylindrical boundary. The combined inertial and boundary effect for the torus has been related to the combined inertial and boundary effect for a sphere by an empirical equation

A Global Challenge: Sustainability of Submicrometer PEO and PVP Fiber Production

The field of submicrometer polymeric production currently has a predominant research focus on morphology and application. In comparison, the sustainability of the manufacture of submicrometer polymeric fibers, specifically the energy efficiency, is less explored. The principles of Green Chemistry and Green Engineering outline frameworks for the manufacture of “greener” products, where the most significant principles in the two frameworks are shown to be centered on energy efficiency, material wastage, and the use of non-hazardous materials. This study examines the power consumption during the production of Polyethylene oxide (PEO) and Polyvinylpyrrolidone (PVP) submicrometer fibers under magnitudes of the key forming parameters to generate fibers via pressure spinning. The energy consumption, along with the fiber diameter, and production rate during the manufacture of fibers is predominantly attributed to the characteristics of polymeric solutions utilized

Environmental Impact of Polymer Fiber Manufacture

This review focuses on the effects on the environment due to the production of polymer-solvent solutions and the manufacture of polymeric fibers of thicknesses from a nanometer up to a millimeter using these solutions. The most common polymeric fiber manufacture methods are reviewed based on their effects on the environment, particularly from the use of hazardous materials and energy consumption. Published literature is utilized to analyze and quantify energy consumption of the manufacturing methods electrospinning, phase separation, self-assembly, template synthesis, drawing and pressurized gyration. The results show that during the manufacturing stage of the lifecycle of polymeric fibers, pressurized gyration is more environmentally efficient primarily due to its mass-producing features and fast processing of polymeric solutions into fibers, it also works best with water-based solutions. Further green alternatives are described such as the use of sustainable polymers and solvents to enhance the environmental benefit. Overall, it is shown that the most effective method of curbing the environmental impact of manufacturing polymeric fibers is the use of nontoxic, water-soluble polymers along with the evasion of toxic solvents

Assessing the impacts of COVID-19 pandemic on agricultural and food systems in Badulla District, Sri Lanka

Peer reviewedPublisher PD

Comparison of some physical and chemical properties of soils under different aged Teak plantations in Kadjuwatte with other sites having healthy growth of Teak in Mahaweli System C, Sri Lanka

Soil is one of the most important natural resources for crop production. Plants require soil to obtain water and nutrients for growth and for anchorage and stability. According to published records, among many factors controlling the distribution and growth performance of Teak (Tectona grandis) are edaphic factors including depth, drainage, texture, moisture status and fertility of both surface and subsurface soils. There is a marked relationship between mineral nutrition of soil and growth of Teak.The study was initiated with the objective of finding the contribution of edaphic conditions on the growth performance of Teak grown in Kadjuwatte, an estate located in Dehiattakandiya, Mahaweli System C belonging to Informatics Agrotech Pvt. Ltd. The total extent of the Estate is 1646 acres and the Teak plantations with the ages ranging from 8 to 18 are spread over 200 ha in the entire Estate. Trees in general show suboptimal performance compared with the reported growth for other parts of Sri Lanka and countries with similar climates. Further, it was also observed that the growth of Teak located in the same District shows better performance compared to the Teak in Kadjuwatte.Three soil samples were taken up to a depth of 45 cm from each block in both Kadjuwatte and the Teak Plantations in Polonnaruwa District. These samples were analysed for both physical and chemical parameters such as soil pH, texture, organic matter, cation exchange capacity, nitrate nitrogen, available phosphorus, potassium, calcium and magnesium. Soil profiles were also made in the plantations in Kadjuwatte and other Teak plantations in the Polonnaruwa District.The results revealed that significant differences (p>0.05) were observed in both physical and chemical properties of soil in plantations in Kadjuwatte compared with the other Teak Plantations in the Polonnaruwa District. Soil pH, Phosphorus, nitrate nitrogen was significantly lower in the soil in Kadjuwatte. pH, Organic matter, Phosphorus, Potassium showed variations between ages even in the same plantation. About 25cm thick hard pan has been identified in soil profile of Kadjuwatte plantation which was absent in other healthy plantations of Teak taken for the comparison.Therefore it can be concluded that both physical and chemical parameters as well as the effective soil depth for tree growth had shown significant impact on the growth of Teak. Fertilisation will help to improve the growth of existing Teak plantations in the Kadjuwatte while planting in locations without hard pan will facilitate growth in the future.

Sales and Production Management System and Reporting using Centralized Database System

In the industry, one of the most extensively utilized systems is the Sales and Production management system. Since there were numerous departments inside the company, building up a shared sales and production management system enabled timely and effective control of the company's stocks, order management, and efficient use. If you do the accounting using manual methods for the administration, as mentioned above, chores will also take a lot of paperwork and workforce. This study suggests a system

The Effectiveness of Farmer Field School Extension Approach for Technology Transfer to Tea Smallholders in Sri Lanka

Although tea smallholders play a dominant role in the tea industry in Sri Lanka, they have faced many constraints such as poor adoption of technology, scarcity of skilled labor and inputs, low productivity, high cost of production, etc. In searching for a viable mechanism to address the technology adoption issues, this study designs to assess the effectiveness of the Farmer Field School (FFS) extension approach implemented in Kandy district in Sri Lanka to improve the adoption rate of cultural practices toward increasing productivity and profitability in tea smallholdings. The stratified purposive sampling technique was performed to select 50 tea smallholders who participated in FFS programs and another 50 tea smallholders who have not attended the same programs (NFFS Group) in eight Grama Niladhari Divisions in the Kandy district. A cross-sectional field survey using a pretested and validated survey instrument was administrated to collect primary data. Using the 5-point Likert scale, indices were developed to measure variables, and descriptive analysis and ordered logistic regression analysis were performed to analyze the data. The results show that there was a significant difference in the adoption of agricultural practices between FFS and NFFS tea smallholders (t %253D3.362, p lt%253B 0.001), the productivity of land (t %253D 1.991, p lt%253B 0.05), and cost of production (t %253D -3.976, p lt%253B 0.001). The results of the ordered logistic regression model revealed that the model was fitted significantly (p lt%253B 0.05) and confirmed that the degree of adoption of recommended cultural practices by tea smallholders was positively and significantly correlated with their educational level (p lt%253B 0.05), attitude on field practices (p lt%253B 0.1), knowledge of tea field technologies (p lt%253B 0.01), experience in tea cultivation (p lt%253B 0.1), tea land productivity (P lt%253B 0.05), and group dynamic interaction in the learning process of tea farm field school-extension related learning activities (p lt%253B 0.05). Hence, this study proved that the FFS approach is a useful agricultural innovation and dissemination platform for improving tea smallholders knowledge and changing their attitude toward the adoption of cultivation practices for improving tea smallholdings land productivity and profitability in Sri Lanka