The first step in the isolation and purification of bioactive compounds from plant material is extraction. Extraction of secondary metabolites such as phenolic acids and flavonoids is difficult due ...to their insoluble nature. While conventional extraction methods such as Soxhlet, heat reflux, and maceration are successful procedures in the extraction of bioactive compounds and the equipment involved in these methods are distinct from each other. An appropriate extraction technique that balances product quality, process efficiency, production costs, and environmentally acceptable methods should be used for the extraction of bioactive compounds from plant tissues. The application of innovative extraction methods in the food industries has been extensively investigated, due to increased consumer expectations for greener options that do not include hazardous chemicals, as well as industry concerns about sustainable, nontoxic extraction techniques. Innovative technologies, such as high hydrostatic pressure (HHP), ultrasound (US), pulsed electric field (PEF), supercritical fluid (SF), and others, are increasingly replacing the conventional methods. The use of novel and combined novel technologies increases extractability, resulting in yields with higher extraction rates. It also yields lower impurities in the final extract and preserves thermo-sensitive compounds, uses different inorganic solvents, and consumes low energy. The purpose of the present review is to evaluate the efficiency of the different conventional, novel, and combined novel technologies involved in the extraction of bioactive compounds from plant materials.
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•The various conventional techniques for extraction of bioactive compounds are reviewed.•The paper also reviewed the various novel technologies for extraction of bioactive compounds.•The focus of the paper is combined novel technologies for extraction of bioactive compounds.•Efficiency of the extraction process can be increased by combining two technologies.
The increasing industrialization and motorization of the world has led to a steep rise for the demand of petroleum-based fuels. Petroleum-based fuels are obtained from limited reserves. These finite ...reserves are highly concentrated in certain regions of the world. Therefore, those countries not having these resources are facing energy/foreign exchange crisis, mainly due to the import of crude petroleum. Hence, it is necessary to look for alternative fuels which can be produced from resources available locally within the country such as alcohol, biodiesel, vegetable oils etc. This paper reviews the production, characterization and current statuses of vegetable oil and biodiesel as well as the experimental research work carried out in various countries. This paper touches upon well-to-wheel greenhouse gas emissions, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, engine performance and emissions, effect on wear, lubricating oil etc.
Ethanol is also an attractive alternative fuel because it is a renewable bio-based resource and it is oxygenated, thereby providing the potential to reduce particulate emissions in compression-ignition engines. In this review, the properties and specifications of ethanol blended with diesel and gasoline fuel are also discussed. Special emphasis is placed on the factors critical to the potential commercial use of these blends. The effect of the fuel on engine performance and emissions (SI as well as compression ignition (CI) engines), and material compatibility is also considered.
Biodiesel is methyl or ethyl ester of fatty acid made from virgin or used vegetable oils (both edible and non-edible) and animal fat. The main resources for biodiesel production can be non-edible oils obtained from plant species such as
Jatropha curcas (Ratanjyot),
Pongamia pinnata (Karanj),
Calophyllum inophyllum (Nagchampa),
Hevca brasiliensis (Rubber) etc. Biodiesel can be blended in any proportion with mineral diesel to create a biodiesel blend or can be used in its pure form. Just like petroleum diesel, biodiesel operates in compression ignition (diesel) engine, and essentially require very little or no engine modifications because biodiesel has properties similar to mineral diesel. It can be stored just like mineral diesel and hence does not require separate infrastructure. The use of biodiesel in conventional diesel engines result in substantial reduction in emission of unburned hydrocarbons, carbon monoxide and particulate. This review focuses on performance and emission of biodiesel in CI engines, combustion analysis, wear performance on long-term engine usage, and economic feasibility.
•Performance, emissions and combustion characteristics of Karanja biodiesel blends.•Lower biodiesel blends produced higher maximum torque than diesel.•At higher loads, higher biodiesel blends produce ...higher BSNOx emissions.•BSHC, BSCO and smoke emissions of KOME blends were lower than diesel.•Combustion duration of lower biodiesel blends was shorter than diesel.
Effect of Karanja biodiesel (Karanja oil methyl ester; KOME) and its blends on engine performance, emissions and combustion characteristics in a direct injection compression ignition (DICI) engine of a medium size utility vehicle with varying engine speed and load has been investigated. Maximum torque attained by 10% and 20% KOME blends were higher than mineral diesel, while higher biodiesel blends produced slightly lower torque. BSFC for lower KOME blends was comparable to mineral diesel however BSFC increased for higher biodiesel blends. BSCO, BSHC and smoke emissions of Karanja biodiesel blends were lower than mineral diesel but BSNOx emissions were slightly higher. Comparative investigation of performance, emissions and combustion characteristics of Karanja biodiesel blends and mineral diesel showed that up to 20% Karanja biodiesel blend can be utilized in an unmodified DICI engine.
Proton pump inhibitors (PPIs) are among the most frequently prescribed medications. Their use is likely even higher than estimated due to an increase in the number of PPIs available without a ...prescription. Appropriate indications for PPI use include
infection, erosive esophagitis, gastric ulcers, and stress ulcer prevention in high-risk critically ill patients. Unfortunately, PPIs are often used off-label for extended periods of time. This increase in PPI usage over the past two decades has called into question the long-term effects of these medications. The association between PPI use and infection, particularly
and pneumonia, has been the subject of several studies. It's proposed that the alteration in gastrointestinal microflora by PPIs produces an environment conducive to development of these types of infections. At least one study has suggested that long-term PPI use increases the risk of dementia. Drug interactions are an important and often overlooked consideration when prescribing any medication. The potential interaction between PPIs and antiplatelet agents has been the subject of multiple studies. One of the more recent concerns with PPI use is their role in the development or progression of chronic kidney disease. There is also some literature suggesting that PPIs contribute to the development of various micronutrient deficiencies. Most of the literature examining the potential adverse effects of PPI use is composed of retrospective, observation studies. There is a need for higher quality studies exploring this relationship.
Vegetables oils are simplest route of biofuel utilization in direct injection compression ignition (DICI) engines however several operational and durability problems are encountered while using ...straight vegetable oils in CI engines due to their high viscosity and low volatility. Reduction of viscosity by blending or exhaust gas heating leads to savings in chemical processing cost incurred on transesterification. In this experimental study, performance, emission and combustion characteristics of Karanja oil blends (K10, K20, K50 and K100) with mineral diesel were investigated in unheated conditions in a direct injection CI engine at different engine loads and constant engine speed (1500 rpm) vis-à-vis baseline data from mineral diesel. Analysis of performance parameters such as brake specific fuel consumption (BSFC), thermal efficiency, and exhaust gas temperature; mass emissions of various gaseous pollutant species; combustion parameters such as in-cylinder pressure rise, instantaneous heat release and cumulative heat release etc. were carried out. Detailed combustion analysis revealed that the combustion duration increased significantly even with smaller concentration of Karanja oil in the fuel blend. HC, CO and Smoke emissions were found to decrease for 20–50% (v/v) Karanja oil content in the fuel blends.
► Finding the feasibility of using minor blends of Karanja oil with diesel in CI engine for decentralized power generation. ► Performance, emission and combustion characteristics of different Karanja oil blends. ► Results show that lower blends (upto 20% v/v) can be readily used as diesel substitute. ► Utilization of higher blends requires modification in the engine hardware.
This paper describes the comparative performance, emissions, combustion characteristics and particulate size-number distribution of 10 and 20% methanol blends ( M10 & M20) with gasoline in a medium ...duty spark ignition transportation engine, typically used in a mid-sized car vis-a-vis baseline gasoline. Brake thermal efficiency of methanol blends was higher than gasoline. Methanol-gasoline blends (gasohol) produced lower CO, NO and smoke emissions than gasoline. The combustion characteristics of gasohol blends were found to be almost identical to gasoline. Minor variations in cylinder pressure were observed for gasohol blends compared to gasoline. Heat release rate for gasoline begins to rise earlier than gasohol at the same engine load and also, peaks of heat release rate for gasohol were wider compared to gasoline. With increasing engine load, combustion duration decreased because at higher engine loads, combustion was relatively faster. Combustion duration of gasohol blends was higher than gasoline, suggesting slower heat release from gasohol. This study indicates that methanol and its blends can be a good replacement of gasoline for transportation engines without any hardware modification as well as any additional serious environmental impact.
An experimental investigation has been carried out to analyze the performance and emission characteristics of a compression ignition engine fuelled with Karanja oil and its blends (10%, 20%, 50% and ...75%) vis-a-vis mineral diesel. The effect of temperature on the viscosity of Karanja oil has also been investigated. Fuel preheating in the experiments – for reducing viscosity of Karanja oil and blends has been done by a specially designed heat exchanger, which utilizes waste heat from exhaust gases. A series of engine tests, with and without preheating/pre-conditioning have been conducted using each of the above fuel blends for comparative performance evaluation. The performance parameters evaluated include thermal efficiency, brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC), and exhaust gas temperature whereas exhaust emissions include mass emissions of CO, HC, NO and smoke opacity. These parameters were evaluated in a single cylinder compression ignition engine typically used in agriculture sector of developing countries. The results of the experiment in each case were compared with baseline data of mineral diesel. Significant improvements have been observed in the performance parameters of the engine as well as exhaust emissions, when lower blends of Karanja oil were used with preheating and also without preheating. The gaseous emission of oxide of nitrogen from all blends with and with out preheating are lower than mineral diesel at all engine loads. Karanja oil blends with diesel (up to 50% v/v) without preheating as well as with preheating can replace diesel for operating the CI engines giving lower emissions and improved engine performance.
To meet stringent vehicular exhaust emission norms worldwide, several exhaust pre-treatment and post-treatment techniques have been employed in modern engines. Exhaust Gas Recirculation (EGR) is a ...pre-treatment technique, which is being used widely to reduce and control the oxides of nitrogen (NOx) emission from diesel engines. EGR controls the NOx because it lowers oxygen concentration and flame temperature of the working fluid in the combustion chamber. However, the use of EGR leads to a trade-off in terms of soot emissions. Higher soot generated by EGR leads to long-term usage problems inside the engines such as higher carbon deposits, lubricating oil degradation and enhanced engine wear. Present experimental study has been carried out to investigate the effect of EGR on soot deposits, and wear of vital engine parts, especially piston rings, apart from performance and emissions in a two cylinder, air cooled, constant speed direct injection diesel engine, which is typically used in agricultural farm machinery and decentralized captive power generation. Such engines are normally not operated with EGR. The experiments were carried out to experimentally evaluate the performance and emissions for different EGR rates of the engine. Emissions of hydrocarbons (HC), NOx, carbon monoxide (CO), exhaust gas temperature, and smoke opacity of the exhaust gas etc. were measured. Performance parameters such as thermal efficiency, brake specific fuel consumption (BSFC) were calculated. Reduction in NOx and exhaust gas temperature were observed but emissions of particulate matter (PM), HC, and CO were found to have increased with usage of EGR. The engine was operated for 96h in normal running conditions and the deposits on vital engine parts were assessed. The engine was again operated for 96h with EGR and similar observations were recorded. Higher carbon deposits were observed on the engine parts operating with EGR. Higher wear of piston rings was also observed for engine operated with EGR.
The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from ...triglycerides (vegetable oils/animal fats) present promising “greener” substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO
2 emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel.
In the present research, experiments were designed to study the effect of reducing Jatropha oil’s viscosity by increasing the fuel temperature (using waste heat of the exhaust gases) and thereby eliminating its effect on combustion and emission characteristics of the engine. Experiments were also conducted using various blends of Jatropha oil with mineral diesel to study the effect of reduced blend viscosity on emissions and performance of diesel engine. A single cylinder, four stroke, constant speed, water cooled, direct injection diesel engine typically used in agricultural sector was used for the experiments. The acquired data were analyzed for various parameters such as thermal efficiency, brake specific fuel consumption (BSFC), smoke opacity, CO
2, CO and HC emissions. While operating the engine on Jatropha oil (preheated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations. However, for higher blend concentrations, performance and emissions were observed to be marginally inferior.
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