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Lightweight materials play a vital role in many industries because of their weight reduction, corrosion resistance, and formability. On the other hand, joining this alloy is a very tedious process for everyone in industries due to incompatibility in metallurgical properties. The thick intermetallic formation, porosity, and segregation of alloys in the weld are the possible causes during welding of dissimilar materials by the fusion welding process. Nowadays, these materials have been joined by solid-state welding friction stir welding. AA2024 and high carbon steel (HCS) were used for friction stir spot welding in this investigation. Tool rotational speed, plunge rate, plunge depth, and dwell time were the major influencing process parameters. Design of experiments and response surface methodology were used to optimize the process parameters to attain maximum lap shear strength of AA2024/HCS.

In present study, high pressure CO2 absorption performance of aqueous N-methyldiethanolamine (MDEA) and its hybrid solvents with anhydrous perazine (PZ) and ionic liquid (IL) 1-butyl-3-methylimidazolium trifluoromethanesulfonate [bmim][OTf] were investigated. The absorption performance of hybrid solvents were carried out to investigate CO2 loading capacity (mol of CO2/mol of solvent), and apparent absorption rate (CO2 capture efficiency, overall rate constant). The CO2 loading capacity of aqueous MDEA and its hybrid solvents were experimentally investigated for a wide range of compositions between pressure ranges of 2 to 50 bar and at three different temperatures (303.15, 313.15, and 333.15 K). Furthermore, apparent absorption rate performance of hybrid solvents were determined at 303.15 K temperature and 2 bar pressure. The effect of temperature, CO2 partial pressure, and ionic liquid (IL) concentrations on CO2 loading of aqueous IL-amines hybrid solvents were also investigated. The results indicated that CO2 loading of hybrid solvents were increased with increase in CO2 partial pressure and IL concentration (up to 10 wt%), further increased concentration of IL suppressed CO2 loading capacity. The CO2 loading capacity of hybrid solvents were also reduced with rise in system's temperature. The addition of IL and anhydrous PZ significantly enhanced CO2 capture efficiency (nCO2) and overall absorption rate constant (k) of aqueous MDEA solvent.

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). Because of many unique features, DESs can be a versatile alternative to ionic liquids and traditional solvents. In this work, DESs were prepared namely allyltriphenylphosphonium bromide-diethylene glycol (ATPPB-DEG) and allyltriphenylphosphonium bromide-triethylene glycol (ATPPB-TEG) into three mole ratios 1:4, 1:10, and 1:16 salt to HBDs. The thermal stability was comprehensively analysed under the temperature range of (30–800) °C. The conductivity and pH values were determined within the temperature range of 293.15 K–343.15 K. The results revealed that the amount and type of HBDs have an effect on these properties. Moreover, the effect of temperature was studied on these properties. As the temperature increases, the conductivity values increase while the pH values decrease. Finally, a new empirical equation was applied to correlate the experimental conductivity and pH data. It was found that this equation is powerful and reliable to correlate these properties of DESs.

The scale deposit containing inorganic/organic molecules or ions collected from Finchaa Sugar Factory (FSF) ethanol plant heat transferring units was investigated. Physical observation indicated that the scale on the heat exchanger surface is because of crystallization. The scales were hard with an average thickness of 1.46 ± 0.17 cm, 1.86 ± 0.14 cm, 2.24 ± 0.18 cm and 2.40 ± 0.22 cm for molasses preheater, molasses heater, reboiler and distillation column, respectively. This shows that precipitation fouling is the type of fouling occurs in the plant. The appearance, texture and color of the scale were noted before the samples were characterized using AAS, XRF and XRD to determine compounds present. AAS, XRF and XRD analysis also demonstrated that among scale forming components calcium oxide (CaO) was the major scale forming compound. Investigation of process water indicated that it has insignificant impact on scale formation. FSF molasses contains an average of 2.24% CaO as compared to 1.5% average composition of CaO molasses. Investigation conducted in this work exhibited that thermal and chemical treatment of molasses is the preferred and recommended.

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) was prepared by using three molar ratios of 1:4, 1:10 and 1:16 salt to HBD. The volumetric properties of aqueous DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15 K. A mathematical equation, so-called Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data of aqueous solution of DESs with respect to the concentration and temperature. The results disclosed that this model is an accurate and reliable model for the prediction of aqueous DES properties. The excess properties, such as excess molar volume and excess isobaric thermal expansion were reported and fitted to two different equations. In order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying the Hepler equation, it was found that DESs with molar ratios of 1:4 and 1:10 are as structure-maker solutes, while the DES 1:16 is a structure-breaking solute in aqueous solutions at different temperatures.

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenylphosphonium bromide- triethylene glycol (ATPPB-TEG) was prepared by using three molar ratios; i.e.,1:4, 1:10, and 1:16 of salt to HBDs. The volumetric properties of aqueous mixture of DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15 K. A mathematical equation, namely Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data. Furthermore, in order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying Hepler equation, it was found that DESs 1:4 and 1:10 are as structure-maker solutes, while DES 1:16 is a structure-breaking solute in aqueous solutions.

Deep eutectic solvents (DESs) are derived from the concomitant reaction of two or more salts i.e. between hydrogen bond acceptor (HBA) and hydrogen bond donors (HBD) components. In this work, DESs were prepared namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) and allyltriphenyl phosphonium bromide-triethylene glycol (ATPPB-TEG) into three molar ratios 1:4, 1:10, and 1:16 salt to HBDs. The carbon dioxide solubility in DESs at temperature of 303.15 K and pressure up to 2 MPa were determined and reported in terms of mole fraction, CO 2 loading and Henry's law constants. Krichevsky–Kasarnovsky equation was used to correlate the solubility data and obtain Henry's law constants at 303.15 K. Finally, the effects of hydrogen bonding within DESs, molar ratio, molar volume, free volume, ether group and alkyl chain length were investigated based on CO 2 solubility in DESs. To the best of our knowledge, this is the first time CO 2 solubility in these DESs was studied.

In this research work, thermophysical properties such as density, refractive index, surface tension, and viscosity of aqueous N-methyldiethanolamine (MDEA) and 1-butyl-3-methylimmidazolium trifluoromethanesulfonate [bmim][OTf], 1-butyl-3-methylimmidazolium acetate [bmim][Ac] hybrid solvents were investigated. All thermophysical properties were investigated at an atmospheric pressure, between the temperature ranges of 298.15 to 343.15 K with an interval of 5 K. In all samples, the concentration of MDEA was kept constant at 30 wt%, while the concentration of the ionic liquids was varied between 5–20 wt%. Experimental investigation demonstrated that the thermophysical properties were mainly dependent on the temperature and the concentration of the ionic liquids. All thermophysical properties were decreased with increase in temperature of the system. An increasing trend was observed in density, refractive index, and viscosity data with the increase in the concentration of the ionic liquids. The surface tension data for all samples under investigated was found to be in decreasing order with the increase in the concentration of the ionic liquids. It was also noticed that the use of two different ionic liquids has a different impact on the thermophysical properties of the hybrid solvents. Empirical correlations were used to correlate the experimental data of all the properties as a function of temperature and concentration of both the components (IL and amine). The correlated data were found to be in good agreement with the experimental data at all concentrations.

In the present study, thermophysical properties such as density, refractive index, surface tension, and viscosity of the concentrated aqueous solution of N-methyldiethanolamine (MDEA), piperazine (PZ), and ionic liquids (ILs) 1-butyl-3-methylimidazolium trifluoromethanesulfonate [bmim][OTf], 1-butyl-3-methylimidazolium acetate [bmim][AC] were investigated. All the properties were measured at atmospheric pressure and temperature ranging from (298.15–343.15) K, with a regular interval of 5 K. The concentrations of N-methyldiethanolamine (MDEA) and piperazine (PZ) were kept constant at 30 and 3 wt%, respectively, while the concentration of ionic liquids [bmim][OTf], [bmim][AC] were varied between 5 and 20 wt%. All the properties under investigation demonstrated their significant dependence on temperature and ionic liquid concentration. Increasing temperature showed decreasing trend of density, viscosity, refractive index, and surface tension of the hybrid solvents. Except for surface tension, density, refractive index, and viscosity were increased by increasing the concentration of ionic liquid in the hybrid solvents. Surface tension data were decreased with an increase in the concentration of ionic liquids at a constant temperature. The thermophysical properties of concentrated aqueous solution of hybrid solvents were correlated using an empirical correlations approach with respect to temperature and concentration. A good agreement was found between the correlated and experimental data at all conditions.

Biodiesel which comes from pure renewable resources provide an alternative fuel option for future. The rapid growth of the biodiesel industry will result in overproduction of less value glycerol and create a superfluity of this impure by-product. The synthesis of alkaline alumina catalyst for polyglycerol production via solvent free base-catalyzed etherification of low value glycerol is reported. The etherification of biodiesel derived glycerol to polyglycerol was studied in a heterogeneous catalysis under solvent free system, using alkalines over γ – alumina catalysts. All the catalysts were prepared by incipient-wetness impregnation of an aqueous solution of alkaline compounds on γ – alumina as a support. The effects of alkaline compound, reaction temperature, catalyst amount, and reaction time in conversion of glycerol to polyglycerol were investigated. The catalyst with potassium loaded on γ -alumina gave the highest basicity and the best catalytic activity for this reaction. The highest glycerol conversion into polyglycerol production was obtained with high yield 79.5% over prepared catalyst respectively. Industrially, the findings attained in this study might contribute towards promoting the biodiesel industry through utilization of its by-products.

In this study, ionic liquid-amine ([BMIM] [AC]+MEA) hybrid solvent was prepared for CO2 capture and its properties were investigated. The hybrid solvent was prepared at different ratios of ionic liquid-amine concentration. The properties such as density, viscosity and refractive index of aqueous ionic liquid-amine ([BMIM][AC]+MEA) hybrid solvent were investigated at different ionic liquid to amine mass ratios of 0.33, 0.6, 1, 1.33 and 1.67 and ionic liquid-amine hybrid mass fraction(w1+w2) % in the aqueous solution of (0.1+0.3), (0.2+0.3), (0.3+0.3), (0.4+0.3), (0.5+0.3) wt.% respectively. The temperature used for each sample investigation was varied from 298.15-313.15K at the intervals of 5 k. From the investigation conducted, it was demonstrated that increasing the concentration of ionic liquids in the aqueous ionic liquid-amine hybrid solvent increased the density, viscosity as well as refractive index of the hybrid solvent. The temperature has a reverse effect on these properties though the effect of temperature on viscosity at a higher temperature greater than 340 k is less dependent on the concentration of the hybrid solvent. It was also observed that small change in temperature has a negligible effect on the density of hybrid solvent.

In the present work, microwave heat pretreatment of jatropha curcas seed particles and use of phase transfer catalyst (PTC) to enhance in-situ transesterification were utilized together. It was observed that use of alkaline BTMAOH as a PTC and microwave heat pretreatment of jatropha curcas seed particles had substantially increased the reaction rate of in-situ transesterification as compared to the reaction conducted with microwave untreated seeds in the absence of BTMAOH as a PTC. Statistical model equation was developed to investigate the interaction effect of reaction variables and establish optimum reaction condition. At optimum condition, experimentally obtained FAME yield (93.7±1.53% w/w) was in close agreement with statistical model predicted FAME yield (96.75%) at 38°C and 37 minutes of reaction time.

In this study, aqueous hybrid solvents from a mixture of aqueous N-methyldiethanolamine (MDEA) and 1-butyl-3-methylimidazolium acetate, [bmim][Ac] as ionic liquids (ILs) were formulated at different mass ratio. In each aqueous hybrid solvents, the concentrations of MDEA were kept constant at 30 wt%. In the hybrid solvents, the solubility of CO2 was investigated at [bmim][Ac] concentration of 10 wt% and 20 wt%, respectively and results were compared with pure aqueous MDEA solvent. It was observed that the solubility of CO2 is significantly improved in the hybrid solvent as compared to the solubility of CO2 in pure aqueous MDEA solvent. However, increasing the concentration of [bmim][Ac] from 10 wt% to 20 wt% has a negative effect on the solubility of CO2 due to viscosity effect. It was also observed that hybrid solvents with 10 wt% [bmim][Ac] has better CO2 loading capacity. Increasing pressure from 10 bar to 20 bar has demonstrated an increase in CO2 absorption capacity as well as CO2 absorption rate. Hybrid solvents prepared from amine and imidazolium ILs will be a promising solvent in the capturing of CO2.

In this study, the solubility of carbon dioxide (CO2) in the aqueous solution of piperazine (PZ) activated N-methyldiethanolamine (MDEA) was investigated. In the aqueous solution the concentrations of the N-methyldiethanolamine (MDEA) and piperazine (PZ) were kept constant at 30 wt. % and 3 wt. %, respectively. The solubility experiments were carried out between the temperatures ranges of 303.15 to 333.15 K. The pressure range was selected as 2-50 bar for solubility of carbon dioxide in the aqueous solution. The solubility of the CO2 is reported in terms of CO2 loading capacity of the solvent. The loading capacity of the solvent is the ratio between the numbers of moles of CO2 absorbed to the numbers of moles of solvent used. The experimental data showed that the CO2 loading increased with increase in CO2 partial pressure, while it decreased with increase in system’s temperature. It was also observed from the experimental data that the higher pressure favors the absorption process while the increased temperature hinders the absorption process of CO2 capture. The loading capacity of the investigated solvent was compared with the loading capacity of the solvents reported in the literature. The investigated solvent showed better solubility in terms of loading capacity.

In the present work, non-edible oil source, Jatropha curcas oil was used with base catalyzed methanol and ethanol to produce biodiesel using in situ transesterification assisted by Benzyltrimethylammonium hydroxide (BTMAOH) as a phase transfer catalyst (PTC). Experimental investigation showed that base catalyzed in situ transesterification reaction rate was enhanced with the use of BTMAOH as a PTC. During the experiment fast formation of biodiesel was observed in relatively shorter time for PTC assisted reaction as compared to the reaction in the absence of PTC. The effect of individual reaction parameters was investigated using response surface methodology (RSM). Optimum operating conditions were also found statistically. Weight fractions of 89 +/- 0.7% fatty acid methyl esters (FAME) yield and 99.4 +/- 0.4% fatty acid ethyl esters (FAEE) yield were produced at optimum reaction condition. The fuel quality of FAME and FAEE was investigated against the fuel quality specification set by ASTM D6751 and EN-14214 standards. (C) 2012 Elsevier Ltd. All rights reserved.

Limited solubility of alcohols in vegetable oils hinders transesterification reaction process. Phase transfer catalysis can be of great advantage to enhance the reaction rates. Addition of cetyltrimethylammonium bromide as a phase transfer catalyst on in situ transesterification of Jatropha curcas L. with alkaline ethanol was investigated. Use of cetyltrimethylammonium bromide increased the yield of fatty acid ethyl esters. Optimum operating conditions were experimentally established. Yield of fatty acid ethyl esters increased from 89.2 wt% to 99.5 wt% with reduced requirement of ethanol by 16.7 v%, sodium hydroxide catalyst by 33.3 wt%, at a lower temperature of 30 °C and reduced mixing speed in shorter reaction time. The quality of fatty acid ethyl esters fuel conforms to the standards of ASTM D6751 and EN-14214.

Transcritical carbon dioxide Rankine cycle (TCRC) has a potential to convert low grade heat source into power. Thus, the objective of this paper is to evaluate TCRC performance based on the first and the second law of thermodynamics for wide and different operating conditions. To address this, TCRC thermal efficiency, exergetic efficiency, utilization ratio and the exergy destruction of the components are analyzed parametrically. Engineering Equation Solver (EES) is used to solve the set of equations and to evaluate the working fluid properties at the given conditions. For the analysis compressor efficiency, turbine efficiency and effectiveness of the regenerator are assumed to be 0.9, 0.9 and 0.95, respectively. The pump inlet pressure was assumed to be 6.2 MPa. It is found that at 10 MPa turbine inlet pressure 240°C is the optimal turbine inlet temperature operating condition. The percentage of exergy destructions at 240°C turbine inlet temperature are 0.94, 4.53, 9.55, 41.23, and 43.74 by the pump, turbine, condenser, heater and regenerator, respectively. Hence, the highest and the smallest exergy destructions are in the regenerator and the pump. This study will help to select the potential component for further improvement.

In the present work, in-situ methanolysis of microwave irradiation heat pre-treated Jatropha curcas l oil in the presence of alkaline benzyltrimethylammonium hydroxide (BTMAOH) as a phase transfer catalysis (PTC) was investigated. Combined use of microwave heat pretreatment of Jatropha curcas l seed particles and alkaline BTMAOH as a PTC drastically reduced the reaction time from 240 to 30 min. The yield of fatty acid methyl ester (FAME) was also increased from 49.7 to 93.5 %. Reaction kinetics was investigated to study the extent of reaction rate. Reaction kinetic study demonstrated that the order of the reaction is a first order reaction at all reaction temperature under investigation. Activation energy of the reaction was found to be 21,641 J/mole. Combined use of microwave heat treatment of Jatropha curcas l seed particles and PTC is promising to enhance the reaction rate of in-situ methanolysis.

The alkaline catalyst derived from the duck-bones was used for conversion of glycerol to polyglycerol via solvent free etherification process. The physicochemical properties of prepared materials were duck–bones were systematically investigated as a catalyst by latest techniques of Thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface properties. TGA showed different trends of duck–bones decomposition from room temperature to 1000C. XRD pattern showed a clear and sharp peaks of a crystalline phase of CaO. The activity of the catalysts was in line with the basic amount of the strong base sites, surface area, and crystalline phase in the catalysts. The prepared catalyst derived from duck–bones provided high activity (99 %) for glycerol conversion and around 68 % yield for polyglycerol production. These ample wastes of duck–bones have good potential to be used as polyglycerol production catalysts due to have high quantity of Ca compare to other types of bones like cow, chicken and fish bones.

Transesterification is a very slow reaction due to limited solubility of alcohol in vegetable oils that strongly affect the reaction rate. Application of phase transfer catalyst (PTC) can be advantageous to improve the solubility of alcohol in oils and increase the rate of reaction. Use of cetyltrimethylammonium bromide (CTMAB) as a PTC on in-situ transesterification of J. curcas l. with alkaline methanol was investigated. Response surface methodology (RSM) was used to statistically evaluate and optimize the in situ transesterification method of biodiesel production. The effects of process variables were investigated using 25 factorial and central composite design (CCD) technique. Mathematical model was developed to predict the yield of fatty acid methyl esters (FAME). After optimizing the process variables using the model equation, FAME yield (88.25wt %) was predicted and compared with the experimental yield (89.3 ± 0.7wt %) obtained at optimal condition. There is a good agreement between the predicted value and the experimental result.

In situ transesterification of Jatropha curcas l. seed with base catalysed alcohol in the presence of cetyltrimethylammonium bromide (CTMAB) as phase transfer catalyst (PTC) was investigated. The yield of fatty acid methyl esters (FAME) increased from 49.7 w% to 89.2 w% in the presence of CTMAB as PTC at 240 minutes of reaction time. Similarly, the yield of fatty acid ethyl esters (FAEE) increased from 84.7 w% to 99.5 w% in the presence of CTMAB as PTC at 150 minutes of reaction time. The quality of biodiesel fuel conforms to the standards of ASTM D6751 and EN-14214.

The rate of transesterification reaction is very slow as oil is sparingly soluble in methanol. In the present work, castor oil as non-edible oil source was investigated for the synthesis of fatty acid methyl ester (FAME). To enhance transesterification reaction, purified castor oil was treated with microwave energy prior to alkaline transesterification reaction. The experimentally observed FAME yield was compared with FAME yield achieved with microwave energy untreated castor oil at the same reaction condition. 95.6 wt. % FAME yield was exhibited with oils treated with microwave energy as compared to 84.034 wt. % FAME yield untreated with microwave energy while the reaction time was reduced from 60 min to 30 min. Central composite Design (CCD) technique of response surface methodology (RSM) was used to investigate the interaction effect of reaction variables and optimize these variables for maximum FAME yield. At optimal condition 96.12 wt. % FAME yield was predicted from model equation while 95.4 ± 0.3 wt. % FAME yield was demonstrated by the experiments conducted twice at optimal condition.

Biodiesel that mostly comes from pure renewable resources provide an alternative fuel option for future because of limited fossil fuel resources as well as environmental concerns. The transesterification of non-edible oils for biodiesel production is one of the promising process for biodiesel production to overcome this future crises of energy. The utilization of waste frying oil into biodiesel have great worth for economization of biodiesel cost as well as the conversion of waste into value added product with environmental protection. The purpose of the present work is to optimize the process of biodiesel production over a heterogeneous clay based catalyst. Particularly, the transesterification of waste frying palm oil with methanol was studied in the presence of montmorillonite clay K-30 as solid base catalyst that have both of acid and basic nature. The observed date was then optimized with the help of Design of Experiments software. The Response Surface Methodology (RSM) based on four-variable central composite design (CCD) with α (alpha) = 2 was used for this purpose. The transesterification process variables were reaction temperature, x1 (40-140oC), reaction period, x2 (60-300 min), methanol/oil ratio, x3 (6:1- 18:1 mol/ mol) and amount of catalyst, x4 (1-5% wt). The results showed that waste frying oil is a good feedstock for biodiesel production and high yield of 78.4% was obtained during optimization of this biodiesel process that was noted after 180 min at temperature 90°C, with a 12:1molar ratio of methanol to waste frying oil and using 3%wt of montmorillonite clay K-30 catalyst.