An insight on hydrogen fuel injection techniques with SCR system for NOX reduction in a hydrogen–diesel dual fuel engine

Internal combustion engines continue to dominate in many fields like transportation, agriculture and power generation. Among the various alternative fuels, hydrogen is a long-term renewable and less polluting fuel (Produced from renewable energy sources). In the present experimental investigation, the performance and emission characteristics were studied on a direct injection diesel engine in dual fuel mode with hydrogen inducted along with air adopting carburetion, timed port and manifold injection techniques. Results showed that in timed port injection, the specific energy consumption reduces by 15% and smoke level by 18%. The brake thermal efficiency and NO_X increases by 17% and 34% respectively compared to baseline diesel. The variation in performance between port and manifold injection is not significant. The unburnt hydrocarbons and carbon monoxide emissions are lesser in port injection. The oxides of nitrogen are higher in hydrogen operation (both port and manifold injection) compared to diesel engine. In order to reduce the NO_X emissions, a selective catalytic converter was used in hydrogen port fuel injection. The NO_X emission reduced upto a maximum of 74% for ANR (ratio of flow rate of ammonia to the flow rate of NO) of 1.1 with a marginal reduction in efficiency. Selective catalytic reduction technique has been found to be effective in reducing the NO_X emission from hydrogen fueled diesel engines.     

Cathodic electrodeposition of Cu2S thin film for solar energy conversion

Cathodic electrodeposition in the presence of EDTA in aqueous solution was used to prepare Cu₂S thin film deposited on Ti substrate. The effect of deposition potential, concentration and deposition time was studied to determine the optimum condition for electro-deposition process. Cyclic voltammetry was performed to elucidate the electrodic processes that occur while potentials for electrodeposition were applied to determine the optimum potential for electrodeposition. The thin films are characterised by X-ray diffractometry. The photoactivity of the deposited films and their conduction types were evaluated using photoelectrochemical technique. The band gap energy and type of optical transitions were determined from optical absorbance data.     

Hydrogen adsorption properties of Ag decorated TiO2 nanomaterials

In this work, we present the synthesis of Ag doped TiO₂ materials. The products are characterized by powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption, and hydrogen adsorption. The Ag/TiO₂ materials exhibit 3.65 times higher in hydrogen adsorption capability compared with the non-doped TiO₂ materials thank to the existence of Ti³⁺ species, which are Kubas-type hydrogen adsorption centers, and the Ag nanoparticles which provide spillover effects. We believe that this is the first time that both Kubas-type adsorption and spillover are exploited in the design of novel hydrogen storage materials.     

Statistical optimization of conditions for minimum H2 consumption in mixed anaerobic cultures: Effect on homoacetogenesis and methanogenesis

Hydrogen (H₂) production using mixed anaerobic cultures often suffers severe yield reduction due to the syntrophic association between H₂ consumers (methanogens and homoacetogens) and H₂ producers (acidogens). The objective of this study was to uncouple the syntrophic association between H₂ producers and consumers by optimizing conditions for minimum H₂ consumption using a Box–Behnken design approach. The factors investigated in this study include temperature, pH and linoleic acid (LA) concentration. A quadratic response surface model was developed to predict the H₂ consumed by mixed anaerobic cultures and the optimum conditions for minimum H₂ consumption were 38 °C, pH 5.5 and 2 g L⁻¹ LA. Methanogenesis was inhibited in cultures fed 2 g L⁻¹ LA and maintained at pH 6.0 and 53 °C. In comparison, both methanogenesis and homoacetogenesis were inhibited in cultures fed 1–2 g L⁻¹ LA and maintained at a pH of 4.5 (Fig. 2B and 2E and Table 2 Expt. # 1, 2 and 11). Microbial diversity analysis revealed that LA fed cultures was dominated by spore forming Clostridium sp. in addition to Syntrophus aciditrophus. In comparison, control cultures were dominated by Eubacterium sp., Methanocalculus halotolerans and Methanococcoides alaskense. This study described an approach for regulating H₂ consumption in mixed cultures by optimizing process and environmental factors. Understanding the effects of these individual factors and their interaction is important in the full-scale operation of H₂ production facilities.     

Effect of inhibitors on hydrogen consumption and microbial population dynamics in mixed anaerobic cultures

The impact of different chemical microbial stressors (2-bromoethanesulfonate (BES), furfural, fish oil, lauric acid (LUA) and linoleic acid (LA)) on the inhibition of mesophilic hydrogen (H₂) consumption was examined in this study. Hydrogen consumption half-life values were used to compare the extent of inhibition by the different microbial stressing agents. A statistical analysis of the percent H₂ consumed using Tukey's analysis revealed the following trend: Control > fish oil = linoleic acid (LA (C18:2)) = furfural > BES > lauric acid (LUA (C12:0). The terminal restriction fragment length polymorphism (T-RLFP) results indicated that aceticlastic methanogens (Methanosaeta sp., Methanosarcina sp.) and hydrogenotrophic methanogens (Methanococcus sp.) were inhibited by the different chemical stressing agents. Cultures fed LUA and LA had a high abundance of Clostridium sp., Clostridium propionicum and Propionibacterium acnes. In comparison, BES and furfural fed cultures contained large fractions of Clostridium sp., Eubacteria sp. and Bacteroides sp. while in the fish oil fed cultures, the dominant organism detected was Eubacteria sp. This study indicated that H₂ consumption was affected by the chemical stressing agent concentration.     

Nutraceutical applications of garlic and the intervention of biotechnology

Garlic (Allium sativum L.) is an important and widely cultivated plant with both culinary and medicinal uses stemming from its biological activities, which include antibiotic, anticancer, anti-thrombotic, and lipid-lowering cardiovascular effects. Though such medicinal use of garlic existed for centuries, there was little scientific support for its therapeutic and pharmacological properties. However, there has been a recent upsurge of research on garlic aiming to understand its exact mechanism of action in each case so that garlic and its products may have more judicious future applications. Since garlic is vegetatively propagated, its improvement for desired traits through conventional means is difficult. The intervention of biotechnological methods such as tissue culture and gene transfer protocols developed recently hold great promise for improving this crop. Due to new innovations in instrumentation and processing technologies coupled with more judicious experimental models, better products are foreseen in the market. The objective of this article was to review the recent developments made towards understanding the mechanism by which garlic imparts different therapeutic effects as well as to review what biotechnology can offer to improve this crop and its products.     

Experimental investigation on a DI diesel engine fuelled with Madhuca Indica ester and diesel blend

Biodiesel is a fatty acid alkyl ester, which is renewable, biodegradable and non-toxic fuel which can be derived from any vegetable oil by transesterification. One of the popularly used biodiesel in India is Mahua oil (Madhuca Indica). In the present investigation Mahua oil was transesterified using methanol in the presence of alkali catalyst and was used to study the performance and emission characteristics. The biodiesel was tested on a single cylinder, four stroke compression ignition engine. Engine performance tests showed that power loss was around 13% combined with 20% increase in fuel consumption with Mahua oil methyl ester at full load. Emissions such as carbon monoxide, hydrocarbon were lesser for Mahua ester compared to diesel by 26% and 20% respectively. Oxides of nitrogen were lesser by 4% for the ester compared to diesel.     

Performance and exhaust emission of turpentine oil powered direct injection diesel engine

This paper presents the results of experimental work carried out to evaluate the combustion performance and exhaust emission characteristics of turpentine oil fuel (TPOF) blended with conventional diesel fuel (DF) fueled in a diesel engine. Turpentine oil derived from pyrolysis mechanism or resin obtained from pine tree dissolved in a volatile liquid can be used as a bio-fuel due to its properties. The test engine was fully instrumented to provide all the required measurements for determination of the needed combustion, performance and exhaust emission variables. The physical and chemical properties of the test fuels were earlier determined in accordance to the ASTM standards.ResultsIndicated that the engine operating on turpentine oil fuel at manufacture's injection pressure – time setting (20.5 MPa and 23° BTDC) had lower carbon monoxide (CO), unburned hydrocarbons (HC), oxides of nitrogen (NO_x), smoke level and particulate matter. Further the results showed that the addition of 30% TPOF with DF produced higher brake power and net heat release rate with a net reduction in exhaust emissions such as CO, HC, NO_x, smoke and particulate matter. Above 30% TPOF blends, such as 40% and 50% TPOF blends, developed lower brake power and net heat release rate were noted due to the fuels lower calorific value; nevertheless, reduced emissions were still noted.     

Cesium tungsten bronze nanostructures and their highly enhanced hydrogen gas sensing properties at room temperature

In this study, cesium tungsten bronze (Cs_xWO₃) a well-known metal oxide semiconductor and excellent photocatalyst and active photothermal material was used as a sensing material toward hydrogen for the first time. The Cs_xWO₃ nanorods were synthesized using a new hydrothermal method and examined through systematic material investigations. The synthesized Cs_xWO₃ nanorods were coated on SiO₂/Si substrates and subsequently fabricated laterally with multi-finger platinum (Pt)-based electrodes to test their gas detecting properties. The gas detecting property of the prepared material was studied toward very toxic hydrogen gas (10–500 ppm concentration). The gas sensing results demonstrate that the synthesized Cs_xWO₃ material has excellent gas sensing properties toward hydrogen (31.3%), which is overwhelmingly superior to as-prepared WO₃ (4.7%) due to its suitable electrical and optical properties at room temperature (RT). The selectivity results also indicate that the material has outstanding selectivity toward hydrogen compared with different gases such as ammonia and carbon dioxide. The critical features of this material are its high reliability, simple synthesis method, low humidity susceptibility, and high selectivity, making it viable for use in hydrogen sensors. Compared with the as-prepared WO₃, the adsorption capability and conductance of the Cs_xWO₃ surface induces active O₂ functional groups, significantly enhancing the gas sensing properties.     

Val bean (Lablab purpureus L.) proteins: composition and biochemical properties

Val bean (Lablab purpureus L.) proteins were fractionated using the Osborne protein fractionation scheme and biochemically characterized. The seed flour contained 302 g kg^?1 protein (micro‐Kjeldahl N × 6.25) on a dry weight basis. Albumin, globulin, prolamin, and glutelin accounted for 22.8%, 45.1%, 1.8% and 30.3%, respectively, of the total soluble seed proteins. Among the solvents tested, 0.1 mol L^?1 aqueous NaOH was the most effective protein solubilizer. Isoelectric focusing indicated the seed proteins to be predominantly acidic (pI range was ～4–7). Val globulin is a glycoprotein composed of at least three polypeptides in the molecular mass range 51–64 kDa. Albumin fraction had the highest trypsin inhibitory activity, while the globulin fraction registered the highest hemagglutinating activity. Sulfur amino acids were the first limiting amino acids in the total seed proteins. The proportion of essential to total [E/T(%)] amino acids for the bean flour was 36.97%. Among the protein fractions, glutelin fraction had the highest E/T (42.86%) followed by albumin (41.57%), globulin (39.87%), and prolamin (39.15%). Native globulin, although resistant to pepsin, was effectively digested in vitro upon moist heat (100 °C, 30 min) denaturation. Copyright © 2007 Society of Chemical Industry