NEW APPROACHES TO OBTAIN PESTICIDES FROM BIOMASS PYROLYSIS

Biomass can be converted into fuel and value-added products (e.g., biopesticides) by thermochemical processes (e.g., pyrolysis). Lignin, cellulose, and hemicelluloses are the principal components o f plant biomass. All three biomass components were individually, as well as in mixture, pyrolyzed at 550°C in a 0.078 m diameter, 0.52 m high fluidized bed reactor with nitrogen as the fluidizing gas and silica sand as the bed material. The first objective ofthis study was to determine which biomass fractions are responsible for the insecticide activity of biomass bio-oil, by testing the individual toxicity (LC50) of lignin, cellulose and hemicellulose bio-oils, toxicities o f mixtures o f lignin, cellulose and hemicellulose bio-oils as well as toxicities of lignin bio-oil fractions to the Colorado potato beetles (CPB) {Leptinotarsa decemlineata (Say)). The cellulose-hemicellulose bio­ oils combination showed synergism, whereas lignin-cellulose-hemicellulose bio-oils combination had an antagonistic effect. The combination of lignin bio-oil fractions of condenser aqueous phase, condenser organic phase and electrostatic precipitator (ESP) produced additive toxicity. The second objective was to investigate the pesticidal activity o f the bio-oil produced from lignin, cellulose, and hemicellulose individually pyrolyzed at two temperatures, 450 and 550°C, in a bubbling fluidized bed reactor. Three species of insects, the CPB, the cabbage looper (CL) (Trichoplusia ni (Hubner)), and the pea aphid (PA) (Acyrthosiphon pisum (Harris)) were used to assess the range of insecticidal effects of the different bio-oils. Bio-oil from lignin pyrolyzed at 550°C collected by an electrostatic precipitator, was the most active against the CPB at 30 mg/mL, while 3 mg/mL reduced aphid reproduction. The bio-oil did not produce any toxicity for the CL in the same concentration range. The lignin ESP bio-oil at 550°C was further separated iii into polar and non-polar .phases by liquid-liquid extraction using water and dichloromethane (DCM). The ESP-DCM phase retained the activity in the CPB bioassay, and was further ffactioned by semi-preparative high pressure liquid chromatography (HPLC). None o f the individual fractions was active, but a range o f fractions at the end o f HPLC collection when re-combined were found to be active. The recombined oil was analyzed by gas chromatography-mass spectrometry (GC-MS) to identify the active component(s). Six of the ten most abundant peaks from GC-MS chromatogram are polycyclic aromatic hydrocarbons (PAHs). Anthracene was confirmed by standard, while the other possible PAHs are pyrene, phenanthrene, fluoranthene, methyl substituted fluoranthene, and fluoranthene. Stearic and palmitic acid were also confirmed. The PAHs, stearic and palmitic acid are known to be toxic to insects, however none of these compounds is effective individually at the concentrations detected in the bio-oil fractions. Therefore, synergy between these compounds is likely providing the observed activity. From the perspective ofpesticidal action, this will make it harder for an insect such as the CPB to develop resistance to multiple compounds. V Objective three was the optimization of pesticide production using a novel reactor technology that can separate the bio-oil at specific temperature ranges. Lignin was pyrolyzed within a temperature range of ambient-600°C in a 0.13 m diameter, using a 0.15 m high mechanically fluidized reactor (MFR). The toxicity of the different temperature cuts was tested using the CPB bioassay. Bio-oil from the 250-300°C cut was the most active against the CPB, and when analyzed by GC-MS and compared to other temperature cuts, three of the ten most abundant peaks were confirmed as guaiacol, catechol, and stearic acid by standard. However, no CPB mortality was observed for the standard mixture which is the same as their concentration in the bio-oil indicating that other compounds are involved in the overall activity. Although tlie same amount of lignin biomass produces approximately four times more toxic bio-oil when it is pyrolyzed by bubbling bed reactor instead of MFR, the bio-oil production by MFR is more efficient because the expensive liquid-liquid extraction and HPLC separation can be eliminated to retain the pesticidal components o f the bio-oil

Recovery of Valuable Chemicals from Agricultural Waste Through Pyrolysis

Agricultural crop residues are a source of inexpensive biomass to convert into bioproducts. The recovery of valuable chemicals from plant waste would partly solve the disposal issue and offer a more environmentally friendly alternative to synthetic chemical production. One approach to separate and concentrate valuable chemicals from biomass is pyrolysis using a batch reactor process. A mechanically fluidized reactor (MFR) was developed to pyrolyze biomass from ambient to temperatures near 600 °C, forming gases that are then condensed in an ice-chilled condenser to form a bio-oil. The bio-oil produced by the MFR can be separated within temperature ranges, termed one-dimensional or 1-D pyrolysis. Further separation of bio-oil can be achieved by two condensers, one set at a high and one at a low temperature, to isolate the gases by boiling point, termed two-dimensional or 2-D pyrolysis. Char is a by-product of pyrolysis and can be converted into a value-added product, activated carbon, by heating using a jiggled bed reactor (JBR). The biomass investigated, tobacco leaf, tomato plant, spent coffee ground, and hydrolysis and organosolv lignin, were chosen based on availability and the valuable products previously identified in the bio-oil. The thesis objectives were: 1) optimize the 1-D and 2-D MFR for chemical recovery; 2) to isolate bio-oil fractions containing pesticide and antioxidant activity with the 2-D MFR and 3) to compare the activated carbon produced by the JBR from char. After 2-D MFR pyrolysis, a total nicotine recovery of 90% from tobacco bio-oil compared to solvent extraction was obtained when the nicotine concentration was 20%. Both the tobacco and tomato bio-oils could be separated through the 2-D MFR to isolate fractions with high insecticide activity, and the antioxidant concentration in the tomato and organosolv lignin bio-oil was 97 and 91%, respectively. The tomato char produced the activated carbon with the highest adsorption capacity, comparable to commercial coconut shell. In summary, valuable products including pesticides, antioxidants and activated carbon can be recovered from crop waste by MFR pyrolysis demonstrating a successful example of a biorefinery, a sustainable process for converting biomass into a range of bio-based products

FHBC, a Hexa‐\u3cem\u3eperi\u3c/em\u3e‐hexabenzocoronene–Fluorene Hybrid: A Platform for Highly Soluble, Easily Functionalizable HBCs with an Expanded Graphitic Core

Materials based upon hexa‐peri‐hexabenzocoronenes (HBCs) show significant promise in a variety of photovoltaic applications. There remains the need, however, for a soluble, versatile, HBC‐based platform, which can be tailored by incorporation of electroactive groups or groups that can prompt self‐assembly. The synthesis of a HBC–fluorene hybrid is presented that contains an expanded graphitic core that is highly soluble, resists aggregation, and can be readily functionalized at its vertices. This new HBC platform can be tailored to incorporate six electroactive groups at its vertices, as exemplified by a facile synthesis of a representative hexaaryl derivative of FHBC. Synthesis of new FHBC derivatives, containing electroactive functional groups that can allow controlled self‐assembly, may serve as potential long‐range charge‐transfer materials for photovoltaic applications

A Search for Blues Brothers: X-ray Crystallographic/Spectroscopic Characterization of the Tetraarylbenzidine Cation Radical as a Product of Aging of Solid Magic Blue

Magic blue (MB+˙ SbCl6− salt), i.e. tris-4-bromophenylamminium cation radical, is a routinely employed one-electron oxidant that slowly decomposes in the solid state upon storage to form so called ‘blues brothers’, which often complicate the quantitative analyses of the oxidation processes. Herein, we disclose the identity of the main ‘blues brother’ as the cation radical and dication of tetrakis-(4-bromophenyl)benzidine (TAB) by a combined DFT and experimental approach, including isolation of TAB+˙ SbCl6− and its X-ray crystallography characterization. The formation of TAB in aged magic blue samples occurs by a Scholl-type coupling of a pair of MB followed by a loss of molecular bromine. The recognition of this fact led us to the rational design and synthesis of tris(2-bromo-4-tert-butylphenyl)amine, referred to as ‘blues cousin’ (BC: Eox1 = 0.78 V vs. Fc/Fc+, λmax(BC+˙) = 805 nm, εmax = 9930 cm−1 M−1), whose oxidative dimerization is significantly hampered by positioning the sterically demanding tert-butyl groups at the para-positions of the aryl rings. A ready two-step synthesis of BC from triphenylamine and the high stability of its cation radical (BC+˙) promise that BC will serve as a ready replacement for MB and an oxidant of choice for mechanistic investigations of one-electron transfer processes in organic, inorganic, and organometallic transformations

REMITTANCE & DEVELOPMENT: A SENSITIVITY ANALYSIS OF BANGLADESH

Remittances enhance savings and investment and thus help augment capital formation and overall economic development. There is a definite correlation between macro-economic policies operational in the remittance-receiving state and its flow. Here the hypothesis testing of this study indicates that the sensitivity of the GNP or available foreign reserve total to the yearly remittance flow volatile in the case of Bangladesh. Yearly flow of remittance and GNP in Bangladesh are not independent. Very limited empirical works had been done in relation to the actual impact of remittances on incomes. This paper has used to explore the actual impacts of remittance on GNP through scientific analysis. As inflation and exchange rates affect the flow of remittance so it is an important consideration for migrants with the ability and proclivity to save. However, the paper tries to summarize the empirical verification as well as the results and potentiality of such flows of remittance on GNP and the economic growth of Bangladesh

Factors Affecting the Effectiveness of Social Media for Recruitment: An Exploratory Factor Analysis Approach on Private Universities in Bangladesh

Social media are crucial weapons which are used as online recruitment tool at present time.  The study is designed to explore the most crucial factors which affect the effectiveness of social media for recruitment. This paper is basically prepared based on 50 respondents from 10 private universities of Bangladesh to understand the cost and time effectiveness of social media for recruitment. Data used for this study have been collected by using a structured questionnaire of 5 point Likert scale which consists of 15 specific questions. The study is conducted by factor analysis and attained 4 factors including Information Quality, Privacy & Security, Cost & Time and User Friendly that influence the effectiveness of social media for recruitment.  Another statistical tool t-test has been also used to prove the hypothesis. The study also reveals that these four factors are in satisfactory level. From the study concerned people in this arena can get a specific view about the factors that directly influence the effectiveness of social media for recruitment and take corrective actions to improve the present situation. Keywords: Social Media, Social Media Recruitment, Benefits of Social Media Recruitment, Factor Analysis and T-test

Effects of Hard Real-Time Constraints in Implementing the Myopic Scheduling Algorithm

Myopic is a hard real-time process scheduling algorithm that selects a suitable process based on a heuristic function from a subset (Window) of all ready processes instead of choosing from all available processes, like original heuristic scheduling algorithm. Performance of the algorithm significantly depends on the chosen heuristic function that assigns weight to different parameters like deadline, earliest starting time, processing time etc. and the size of the Window since it considers only processes from processes (where, knnk≤). This research evaluates the performance of the Myopic algorithm for different parameters to demonstrate the merits and constraints of the algorithm. A comparative performance of the impact of window size in implementing the Myopic algorithm is presented and discussed through a set of experiments

Correction to: Impact of Continuous Professional Education on Leadership for Rehabilitation Professionals in Bangladesh: A Pilot Study

In the publication of this article, the abstract, full-text of the article and the author's affiliations had some mistakes with regards to the writing/language. The abstract, full-text and the affiliations of the authors has now been updated in the original article. The authors declare that the correction does not change the results or conclusion of this paper