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The objective of the study is to investigate the influence of Polyethylene Terephthalate (PET) recycled plastic bottle fibers on the compressive strength and cracking of concrete. In this study, two types of fiber are used: straight and zigzag fibers whose length and aspect ratio are 40 mm and 40 respectively. 0, 0.75, and 1.25% volume fractions of fibers replacing the volume of coarse aggregates are used in this investigation. According to ACI 211.1-91, design mixing ratio 1:2:3 for M20 concrete and water-cement ratio 0.58 are used. Curing is done in field condition and weathering action is allowed in curing time. The destructive compressive strength test shows that the compressive strength of plain concrete is 19.84 MPa, at 0.75 and 1.25% replacement for concrete with straight fibers are 19.54 and 18.84 MPa, and at 0.75 and 1.25% replacement for concrete with zigzag fibers are 18.49 and 15.69 MPa. The non-destructive compressive strength test shows that the compressive strength of plain concrete is 13.58 MPa, at 0.75 and 1.25% replacement for concrete with straight fibers are 10.36 and 8.82 MPa, and at 0.75 and 1.25% replacement for concrete with zigzag fibers are 8.21 and 8.10 MPa. The use of fibers changes the failure mode. The addition of fibers decreases the workability and cracking of concrete. Zigzag fiber slightly shows interlocking property with concrete. The addition of PET plastic fibers increases the ductility of concrete. Doi: 10.28991/cej-2021-03091684 Full Text: PDF

Disposal of plastic bottles made from Poly-Ethylene Terephthalate (PET) is a worldwide problem. Green concrete, made with one or more recycled items, is also a trendy concept in the sustainable construction sector. The current study is to investigate the possibility of using recycled PET waste bottles as a partial replacement of natural coarse aggregate in green concrete to get marginal effective compressive strength and workability. Two different sizes of PET fiber such as 10mm*10mm and 19mm*19mm are used. Four different replacement percentages such as 0% (control), 1%, 5%, and 10% of coarse aggregate are adopted with a fixed water-cement ratio of 0.42. A total of 42 cylindrical specimens are prepared and conventional water curing is done for 7 days and 28 days. Compressive strength for control specimen (0%) after 7 days and 28 days curing is found as 39.96 MPa and 53.42 MPa respectively. On the other hand, the compressive strength of specimens with 10mm*10mm plastic fiber is found to be 22.40 MPa, 16.14 MPa & 11.83 MPa after 7 days curing and 38.48 MPa, 25.81 MPa & 20.08 MPa after 28 days of curing for 1%, 5%, and 10% replacement of coarse aggregate respectively. For 19mm*19mm plastic fibers, these values are 21.22 MPa, 7.99 MPa & 4.29 MPa after 7 days of curing and 35.82 MPa, 11.36 MPa & 7.03 MPa after 28 days of curing for the same percentages. The findings of the study may serve as a guideline for deciding the replacement percentage and fiber size for preparing PET-based green concrete.

Background:Ravenia spectabilis is a medium tall shrub found widespread in South America. It also found in India, Pakistan, Bangladesh etc. Few alkaloid and steroid compounds were reported from the plant previously.Materials and Methods:Methanol extract from the stems of Ravenia spectabilis were partitioned into n-hexane, carbon tetrachloride, chloroform and aqueous soluble fractions, respectively. The crude methanol extract, carbon tetrachloride fraction and chloroform fraction were fractionated by column chromatography of Silica gel and Sephadex LH-20 for isolation and purification of compounds. The structures of the isolated compounds were determined by extensive NMR spectral analysis, including 2D NMR, mass spectroscopy etc.Results:Ten compounds, γ-fagarine (1), ravenoline (2), N-methyl atanine (3),2,3,3,5-tetramethyl-2,3,4,5- tetrahydrofurano [3,2-c] quinolin-4-one (4), arborinine (5), 3-geranyl indole (6), atanine (7), steroids sitosta-4-en- 3-one (8), stigmasterol (9) and 3-methoxy-4-hydroxy cinnamic acid (10) were isolated from the stems of Ravenia spectabilis.Conclusion:Compounds N-methyl atanine (3), 2,3,3,5-tetramethyl-2,3,4,5-tetrahydrofurano [3,2-c] quinolin-4-one (4), 3-geranyl indole (6), sitosta-4-en-3-one (8) and 3-methoxy-4-hydroxy cinnamic acid (10) were isolated from this plant for the first time. 3-geranyl indole (6) was also isolated second time from natural sources.

Introduction: The comprehensive research on the chemical composition of citronella grass led to various advantages, including the development of analytical tools for quality evaluation, which is the primary reason the plant is cultivated. Attacks by pests such as stink bugs, brown planthoppers, grasshoppers, ladybugs, and aphids are the most significant threat to crop productivity. Other problems include grasshoppers. This assault slows the development of the rice plants, resulting in a decrease in productivity or possibly preventing harvesting altogether. Applying chemical pesticides may help minimize the number of illnesses and pests. Using chemical pesticides over an extended period, on the other hand, may wreak havoc on the environment. Objective: This review aims to examine the biological & insecticidal effectiveness of citronella oil, which can help to understand to use of this oil to control insects and mosquitos. Method: Multiple computerized databases, such as PubMed, Google Scholar, ScienceDirect, etc., were used to write the paper. Result. The medicinal benefits of Citronella oil have been extensively documented, and the oil's components have been well studied. Citronella oil has been used as an antifungal, antiparasitic, effective insect repellent, and antibacterial, thanks to extensive research into its medicinal potential. Conclusion: Oil of citronella contains citronellol, citronellal, and geraniol. If they enter the environment, some will vaporize. In water, they evaporate slowly. Once vapours are airborne, their half-lives range from 38 minutes to 3.2 hours. Instead, microbes degrade citronellol and geraniol.