Effects of Waste Cooking Oil Biodiesel Use on Engine Fuel Consumption and Emissions: a Study on the Impact on Oxidation Catalyst and Particulate Filter

Abstract The wide use of biodiesel has been driven by its reduction potential on greenhouse emissions from diesel engines without significant technological modifications. In this study a diesel engine for non-road applications has been fuelled with Waste Cooking Oil biodiesel blended with commercial fossil fuel at 6% and 30% v/v. In line with literature trends, experimental results indicate a significant reduction of PM emissions and only a slight increase in NOx emissions. This study has been focused on diesel emissions and in particular on the analysis of PM/NO2 ratio in presence of the Diesel Oxidation Catalyst (DOC). In fact, although the NO2/NOx ratio on raw exhaust is almost unaffected, the use of biodiesel shows a slight reduction of the NO-NO2 light-off temperature. This reduction can ensure more favorable operating conditions for the Diesel Particulate Filter (DPF), and has a positive effect on fuel consumption reduction. In order to deeply analyze these issues, a numerical model of an Aftertreatment system (AS) representing the a DOC and a DPF has been developed and validated with experimental data

Control Strategy Influence on the Efficiency of a Hybrid Photovoltaic-Battery-Fuel Cell System Distributed Generation System for Domestic Applications☆

AbstractThe full exploitation of locally available renewable resources together with the reduction of system installation and management costs are key issues of diffused Distributed Generation (DG). In the given context, hybrid systems are already at an advanced stage of development which typically integrate several sub-systems. In such hybrid systems, Renewable Energy Sources generation systems (e.g. photovoltaic panels) are coupled to energy storage devices (electric batteries) and with programmable generators (a diesel generator or, more recently, with a sub-system based on fuel cells) allowing stable operations under a wide range of conditions. In this paper a solution which uses hydrogen and fuel cells as a programmable source is presented and is studied by means of a mixed experimental and numerical: a Hardware-In-Loop test bench designed and realized at the Department lab, able to reproduce the behavior of a hybrid system for domestic applications. The system is controlled by means of a rule-based control strategy acting on the common DC-bus whose optimization has a significant influence both on system design and on its overall system energy performances. Results show that Rule-Based strategy have a great potential towards cost reduction and components lifetime increase, while energy efficiency mainly depends on correct system sizing

Hybridase activity of human ribonuclease-1 revealed by a real-time fluorometric assay

Human ribonuclease-1 (hRNase-1) is an extracellular enzyme found in exocrine pancreas, blood, milk, saliva, urine and seminal plasma, which has been implicated in digestion of dietary RNA and in antiviral host defense. The enzyme is characterized by a high catalytic activity toward both single-stranded and double-stranded RNA. In this study, we explored the possibility that hRNase-1 may also be provided with a ribonuclease H activity, i.e. be able to digest the RNA component of RNA:DNA hybrids. For this purpose, we developed an accurate and sensitive real-time RNase H assay based on a fluorogenic substrate made of a 12 nt 5′-fluorescein-labeled RNA hybridized to a complementary 3′-quencher-modified DNA. Under physiological-like conditions, hRNase-1 was found to cleave the RNA:DNA hybrid very efficiently, as expressed by a k(cat)/K(m) of 330 000 M(−1) s(−1), a value that is over 180-fold higher than that obtained with the homologous bovine RNase A and only 8-fold lower than that measured with Escherichia coli RNase H. The kinetic characterization of hRNase-1 showed that its hybridase activity is maximal at neutral pH, increases with lowering ionic strength and is fully inhibited by the cytosolic RNase inhibitor. Overall, the reported data widen our knowledge of the enzymatic properties of hRNase-1 and provide new elements for the comprehension of its biological function

Fibronectin-binding protein B (FnBPB) from Staphylococcus aureus protects against the antimicrobial activity of histones

Staphylococcus aureus is a Gram-positive bacterium that can cause both superficial and deep-seated infections. Histones released by neutrophils kill bacteria by binding to the bacterial cell surface and causing membrane damage. We postulated that cell wall–anchored proteins protect S. aureus from the bactericidal effects of histones by binding to and sequestering histones away from the cell envelope. Here, we focused on S. aureus strain LAC and by using an array of biochemical assays, including surface plasmon resonance and ELISA, discovered that fibronectin-binding protein B (FnBPB) is the main histone receptor. FnBPB bound all types of histones, but histone H3 displayed the highest affinity and bactericidal activity and was therefore investigated further. H3 bound specifically to the A domain of recombinant FnBPB with a K D of 86 nM, 20-fold lower than that for fibrinogen. Binding apparently occurred by the same mechanism by which FnBPB binds to fibrinogen, because FnBPB variants defective in fibrinogen binding also did not bind H3. An FnBPB-deletion mutant of S. aureus LAC bound less H3 and was more susceptible to its bactericidal activity and to neutrophil extracellular traps, whereas an FnBPB-overexpressing mutant bound more H3 and was more resistant than the WT. FnBPB bound simultaneously to H3 and plasminogen, which after activation by tissue plasminogen activator cleaved the bound histone. We conclude that FnBPB provides a dual immune-evasion function that captures histones and prevents them from reaching the bacterial membrane and simultaneously binds plasminogen, thereby promoting its conversion to plasmin to destroy the bound histone

Reversible Wettability Changes in Colloidal TiO2 Nanorod Thin-Film Coatings under Selective UV Laser Irradiation

We demonstrate the light-induced, reversible wettability of homogeneous nanocrystal-based, thin-film coatings composed of closely packed arrays of surfactant-capped anatase TiO2 nanorods laterally oriented on various substrates. Under selective pulsed UV laser excitation, the oxide films exhibit a surface transition from a highly hydrophobic and superoleophilic state (water and oil contact angles of 110° and less than 8°, respectively) to a highly amphiphilic condition (water and oil contact angles of 20° and 3°, respectively). A mechanism is identified according to which the UV-induced hydrophilicity correlates with a progressive increase in the degree of surface hydroxylation of TiO2. The observed wettability changes are not accompanied by any noticeable photocatalytic degradation of the surfactants on the nanorods, which has been explained by the combined effects of the intense and pulsed irradiation regime and of the rodlike nanocrystal morphology. The organic ligands on the oxide are instead assumed to rearrange conformationally in response to the lightdriven surface reconstruction. The amphiphilic state of the UV-irradiated TiO2 films is then considered as the macroscopic wetting result of alternating hydrophilic and oleophilic surface domains of nanoscale extension. Upon prolonged storage in the dark, ambient oxygen removes the newly implanted hydroxyl groups from the TiO2 surfaces and consequently affects again the conformations of ligands such that the films are allowed to recover their native hydrophobic/superoleophilic properties

Bacterial Expression of Mouse Argonaute 2 for Functional and Mutational Studies

RNA interference (RNAi) is a post-transcriptional gene-silencing process that occurs in many eukaryotic organisms upon intracellular exposure to double-stranded RNA. Argonaute 2 (Ago2) protein is the catalytic engine of mammalian RNAi. It contains a PIWI domain that is structurally related to RNases H and possibly shares with them a two-metal-ion catalysis mechanism. Here we describe the expression in E. coli of mouse Ago2 and testing of its enzymatic activity in a RISC assay, i.e., for the ability to cleave a target RNA in a single position specified by a complementary small interfering RNA (siRNA). The results show that the enzyme can load the siRNA and cleave the complementary RNA in absence of other cellular factors, as described for human Ago2. It was also found that mutation of Arg669, a residue previously proposed to be involved in substrate and/or B metal ion binding, doesn’t affect the enzymatic activity, suggesting that this residue doesn’t belong to the active site

Processing and characterization of durum wheat bread enriched with antioxidant from yellow pepper flour

The effect of the addition of yellow pepper flour on bread physico-chemical and sensorial properties was addressed in this study. In particular, vegetable flour concentration was set at 25%; in order to optimize the bread sensorial properties, yellow pepper flour was separately hydrated at three different water content levels. Texture analysis were carried out on both dough and bread samples to evaluate their firmness. Furthermore, tomographic analysis was performed on the same samples in order to provide a more detailed view of their texture. Estimation of the glycemic response, determination of the carotenoids content and sensory analysis of the fortified bread were also determined. Results highlighted that the highest glycemic index was achieved in bread sample having the highest water content and that showed the worst results in terms of texture. Among the studied samples, bread with medium hydration level showed good structural characteristic, double anti-oxidant content compared to the control bread (CTRL S) and the highest sensorial quality

In-plane Aligned Colloidal 2D WS2 Nanoflakes for Solution- Processable Thin Films with High Planar Conductivity

Two-dimensional transition-metal dichalcolgenides (2D-TMDs) are among the most intriguing materials for next-generation electronic and optoelectronic devices. Albeit still at the embryonic stage, building thin films by manipulating and stacking preformed 2D nanosheets is now emerging as a practical and cost-effective bottom-up paradigm to obtain excellent electrical properties over large areas. Herein, we exploit the ultrathin morphology and outstanding solution stability of 2D WS2 colloidal nanocrystals to make thin films of TMDs assembled on a millimetre scale by a layer-by-layer deposition approach. We found that a room-temperature surface treatment with a superacid, performed with the precise scope of removing the native insulating surfactants, promotes in-plane assembly of the colloidal WS2 nanoflakes into stacks parallel to the substrate, along with healing of sulphur vacancies in the lattice that are detrimental to electrical conductivity. The as-obtained 2D WS2 thin films, characterized by a smooth and compact morphology, feature a high planar conductivity of up to 1 μS, comparable to the values reported for epitaxially grown WS2 monolayers, and enable photocurrent generation upon light irradiation over a wide range of visible to near-infrared frequencie