16,114 research outputs found
A study into the effect of concentration process on the yield of rotenone from the extract of local plant species (Derris elliptica)
Bio-pesticides are becoming increasingly important as pest management tools in various cropping systems in the tropics essentially to remedy problems associated with the indiscriminate use of ‘hard’ inorganic pesticide and interest in organic agriculture. In the few decades, many bio-pesticidal products, both microbial-based (bacteria, fungi, microsprodia, entomopathogenic nematodes, viruses) and plant-based botanicals (rotenone and azadiracthin) had been studied for use against insect pests in the tropics. In this paper, the effect of the concentration process towards the yield of rotenone; mg and its concentration; mg/ml are studied extensively. The raw plants were collected from Kota Johor Lama, Johor and sorted to collect the root and stem. Only the root and stem were utilized as a raw material of the extraction process. The root and stem were extracted using the Normal Soaking Extraction (NSE) at 28 0C to 30 0C with 95 % (v/v) of acetone as a solvent and the solvent-to-solid ratio of 10 ml/g). The extraction was carried out for 24 hours. The liquid crude extract was concentrated further (the solvent removed under reduced pressure) using the rotary evaporator at 50 0C and 80 mbar of vacuum pressures. The fractions of the liquid crude extract were collected for each interval time (15 mins/1.0 ml/fraction). Each fractions were diluted 1/100 with acetone and further cleaned up prior to determination of rotenone content; mg and concentration; mg/ml by using the High Performance Liquid Chromatography (HPLC). Significant effect of the concentration process against the yield of rotenone; mg was recorded and shows a significant thermal degradation or dissipation of rotenone content at higher operating temperature. The possibilities for better exploitation and identification of the effective operating parameters will be discussed
Standardization of the bio-active compounds (rotenoids) from the extract of local plant species (derris elliptica) using the internal standard method of high performance liquid chromatography (HPLC)
It is well known now that some plant species represent an efficient factory of chemicals, which are manufactured and used as bio-weapons against pest attacks. Extensive work has been done during the last few decades on these potentially useful compounds. During the last few decades a growing interest has been paid for safe agricultural production i.e free residual toxicity hazards to human beings and to the environment. Plant extracts-based biocides possess a great advantage compared with the chemical ones. Their efficacies are also acceptable. Research carried out was to standardize and determine the bio-active compounds from the extract of local plant species (Derris elliptica) using the internal standard method of the isocratic High Performance Liquid Chromatography (HPLC) analysis system. The raw plants were collected from Kota Johor Lama, Johor and sorted to collect the root and stem. Only the root and stem were utilized as a raw material of the extraction process. The root and stem were extracted by using the Normal Soaking Extraction (NSE) method at 28 0C to 30 0C with 95.0 % (v/v) of acetone as a solvent and the solvent-to-solid ratio of the extraction is (10.0 ml/g). The extraction was carried out for 24 hours and further cleaned up to remove fine debris of root and stem prior to determination of the rotenone and its derivatives content. The rotenone cube resin of SAPHYR S.A.R.L (France) was used to verify the appearances of the compounds in the extract. The employed method of analysis shows significant appearances of the bio-active compounds in the extract compared with the commercial grade of rotenone cube resin
Normal soaking extraction (NSE) of rotenone from Derris elliptica
Derris elliptica or the tuba plant contains rotenone, bio-active compound known that has the potential to be used as bio-pesticide. Bio-pesticide is the best-known alternative bio-pesticide which has the potential to replace the use of conventional pesticides, as it is more environmentally friendly. The main objective of the paper is to obtain the best extraction solvent for optimizing the yield in rotenone extraction. Rotenone was extracted from Derris root using three different parts of roots and three types of solvent in Normal Soaking Extraction (NSE). The types of Derris roots are: (1) Fine root (2) Coarse root (3) Stem. The three types of solvent system are: (1) Acetone 95 % (v/v), (2) Chloroform 99.9 % (v/v) and (3) a mixture of ethanol: H2O (9:1) added with oxalic acid (1mg/ml). The liquid crude extracts were further cleaned up to remove the fine debris of roots. The presence of rotenone was confirmed using qualitative analysis Thin Layer Chromatography (TLC) and thereupon the determination of rotenone content was carried out using High Performance Liquid Chromatography (HPLC). From the results obtained, it was found that the Normal Soaking Extraction (NSE) using acetone 95 % (v/v) was the best method to extract the highest yield of rotenone; 1.14 % (w/w)
Blind image separation based on exponentiated transmuted Weibull distribution
In recent years the processing of blind image separation has been
investigated. As a result, a number of feature extraction algorithms for direct
application of such image structures have been developed. For example,
separation of mixed fingerprints found in any crime scene, in which a mixture
of two or more fingerprints may be obtained, for identification, we have to
separate them. In this paper, we have proposed a new technique for separating a
multiple mixed images based on exponentiated transmuted Weibull distribution.
To adaptively estimate the parameters of such score functions, an efficient
method based on maximum likelihood and genetic algorithm will be used. We also
calculate the accuracy of this proposed distribution and compare the
algorithmic performance using the efficient approach with other previous
generalized distributions. We find from the numerical results that the proposed
distribution has flexibility and an efficient resultComment: 14 pages, 12 figures, 4 tables. International Journal of Computer
Science and Information Security (IJCSIS),Vol. 14, No. 3, March 2016 (pp.
423-433
Structural response of SSME turbine blade airfoils
Reusable space propulsion hot gas-path components are required to operate under severe thermal and mechanical loading conditions. These operating conditions produce elevated temperature and thermal transients which results in significant thermally induced inelastic strains, particularly, in the turbopump turbine blades. An inelastic analysis for this component may therefore be necessary. Anisotropic alloys such as MAR M-247 or PWA-1480 are being considered to meet the safety and durability requirements of this component. An anisotropic inelastic structural analysis for an SSME fuel turbopump turbine blade was performed. The thermal loads used resulted from a transient heat transfer analysis of a turbine blade. A comparison of preliminary results from the elastic and inelastic analyses is presented
Alat Pendingin dan Pemanas Portable Menggunakan Modul Termoelektrik Tegangan Input 6 Volt dengan Tambahan Heat Pipe sebagai Media Pemindah Panas
Portable coolers and heaters use thermoelectric modules with an additional heat pipe as a heat transfer median. This research is to know the cooling temperature that can be achieved by the utilization of thermoelectric heat exhaust as heater with 6 volt input voltage. The effect of heat pipe USAge on cooling and heating temperatures is also observed. In this study the use of heat pipe provides a better cooling effect where the temperature is lower than the test without heat pipes for 50 minutes. Achievement of cooling and heating chamber under non-heat-free heat pipe 23.41 oC and 32.36 oC, whereas by using heat pipe the achievement of cooling and heating chamber reaches 22.83 oC and 30.52 oC. Tests by using an additional heat pipe as a heat transfer achievement of cooling chamber and heating chamber become lower compared with testing without heat pipe
Size versus truthfulness in the house allocation problem
We study the House Allocation problem (also known as the Assignment problem), i.e., the problem of allocating a set of objects among a set of agents, where each agent has ordinal preferences (possibly involving ties) over a subset of the objects. We focus on truthful mechanisms without monetary transfers for finding large Pareto optimal matchings. It is straightforward to show that no deterministic truthful mechanism can approximate a maximum cardinality Pareto optimal matching with ratio better than 2. We thus consider randomized mechanisms. We give a natural and explicit extension of the classical Random Serial Dictatorship Mechanism (RSDM) specifically for the House Allocation problem where preference lists can include ties. We thus obtain a universally truthful randomized mechanism for finding a Pareto optimal matching and show that it achieves an approximation ratio of eovere-1. The same bound holds even when agents have priorities (weights) and our goal is to find a maximum weight (as opposed to maximum cardinality) Pareto optimal matching. On the other hand we give a lower bound of 18 over 13 on the approximation ratio of any universally truthful Pareto optimal mechanism in settings with strict preferences. In the case that the mechanism must additionally be non-bossy, an improved lower bound of eovere-1 holds. This lower bound is tight given that RSDM for strict preference lists is non-bossy. We moreover interpret our problem in terms of the classical secretary problem and prove that our mechanism provides the best randomized strategy of the administrator who interviews the applicants
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