Combustion Characteristics of Hydrogen/Air Mixtures in a Plasma-Assisted Micro Combustor

This work performs an analysis of plasma-assisted non-premixed H2-air flames in Y-shaped micro combustors in the presence of field emission dielectric barrier discharge (FE-DBD) plasma actuators. The combustion, flow, and heat transfer characteristics are numerically investigated, and the effect of sinusoidal plasma discharges on combustion performance is examined at various equivalence ratios (φ). A coupled plasma and chemical kinetic model is implemented, using a zero-dimensional model based on the solution of the Boltzmann equation and the ZDPlasKin toolbox to compute net charges and radical generation rates. The estimated body forces, radical production rates, and power densities in the plasma regions are then coupled with hydrogen combustion in the microchannel. Plasma-assisted combustion reveals improvements in flame length and maximum gas temperature. The results demonstrate that FE-DBDs can enhance mixing and complete the combustion of unreacted fuel, preventing flame extinction. It is shown that even in cases of radical and thermal quenching, these plasma actuators are essential for stabilizing the flame

Optical Diagnostics for Solid Rocket Plumes Characterization: A Review

In recent decades, solid fuel combustion propulsion of spacecraft has become one of the most popular choices for rocket propulsion systems. The reasons for this success are a wide range of applications, lower production costs, simplicity, and safety. The rocket’s plumes leave the nozzle at high temperatures; hence, the knowledge of produced infrared (IR) emissions is a crucial aspect during the design and tests of the rocket motors. Furthermore, rocket plume composition is given by N2, H2, H2O, CO and CO2, while solid rocket motors (SRM) additionally inject some solid particles, given by metal fuel additives in the propellant grain, i.e., aluminum oxide (Al2O3) particles. The main issue is the detection of the particles remaining in the atmosphere due to the exhaust gas of the solid rocket propulsion system that could have effects on ozone depletion. The experimental characterization of SRM plumes in the presence of alumina particles can be conducted using different optical techniques. The present study aims to review the most promising ones with a description of the optics system and their potential applications for SRM plume measurements. The most common measurement techniques are infrared spectroscopy imaging, IR imaging. UV–VIS measurements, shadowgraph, and Schlieren optical methods. The choice of these techniques among many others is due to the ability to study the plume without influencing the physical conditions existing in and around the study object. This paper presents technical results concerning the study of rocket engines plumes with the above-mentioned methods and reveals the feasibility of the measurement techniques applied

Plasma actuation for lifted flame stabilization in coaxial methane-air flow

The flame stabilization represents a relevant issue in aero-engine design. In fact, the growing demand of pollutant emissions reduction without significant losses of the combustion efficiency has driven the efforts of the scientific community towards lean flames. Lean fuel mixtures, characterized by low temperature flames, could manifest an unstable behaviour which can easily lead to the flame extinction due to the establishment of the blowout condition. This requires the implementation of control systems to avoid flame instability occurrence. The present work shows an investigation of the impact of dielectric barrier discharge (DBD) plasma actuation on lifted flame stabilization in a methane CH4-air Bunsen burner at ambient conditions. Two different plasma actuator configurations, powered with a high voltage (HV)/high frequency sinusoidal signal, have been investigated. Once the best actuator configuration was selected, the efficiency of the plasma actuation has been evaluated in terms of the flame lift-off distance, length and shape. In particular, in order to change the actuator power dissipation, different peak-to-peak voltages Vpp were tested, while the actuation frequency was kept equal to 20 kHz. The application of plasma discharges to flame stabilization leads to plasma-attached flames or plasma-enhanced lifted flames, depending on the air and fuel flow rates. At air flow rate of 1.54 g/s, plasma actuation allowed to decrease the lift-off height until the fuel jet velocity was below about 0.05 m/s thanks to the extension of the flame region upstream, toward the burner exit section. Beyond this value, it had no significant impact on the flame lift-off height, even though the amplitude of the lift-off height oscillations reduced coupled with a more stable behaviour of the lifting flame. The benefit of the plasma actuation increased by reducing the air flow rate to 1.35 g/s. In this condition, plasma-assisted flame reattachment was evident at each fuel velocity, in combination with an increasing flame height proportionally to the fuel jet velocity

Metabolomic profiling of food matrices: Preliminary identification of potential markers of microbial contamination

The research aimed to generate an early warning system highlighting in real-time bacterial contamination of meat matrices and providing information which could support companies in accepting or rejecting batches. Current microorganisms’ detection methods rely on techniques (plate counting), which provide retrospective values for microbial contamination. The purpose of this research was to evaluate the ability of the headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) methodologies to detect volatile organic carbons (VOCs), which may be associated to a peculiar microbiological contamination of food. The disposal of fast headspace gas chromatography-mass spectrometry (HS-SPME-GC/MS) able to accurately and rapidly (30 min per sample) detect pathogens in raw meat could replace the traditional and time-consuming (3 to 4 days) standardized microbiological analysis required by regulations. Experiments focused on qualitative and quantitative evaluations of VOCs produced by Salmonella Typhimurium, Campylobacter jejuni, and Staphylococcus aureus in different types of raw meat (beef, pork, chicken). HS-SPME-GC/MS allowed to use smaller sample volumes compared to traditional methods with no sample processing and the potentiality for its application on various food matrices for the detection of a wide variety of pathogens. Data analysis showed the identification of unique VOCs’ profiles being possible markers of meat contamination due to their association to specific pathogens. The identification of VOCs markers in association to selected bacterial pathogens and their metabolites could support the rapid determination of specific meat samples contamination. Further research is required to outline-specific metabolic profiles for each microorganism responsible of meat contamination and prevent false positives

Quantitative determination of free D-Asp, L-Asp and N-methyl-D-aspartate in mouse brain tissues by chiral separation and Multiple Reaction Monitoring tandem mass spectrometry

Several studies have suggested that free D-Asp has a crucial role in N-methyl D-Asp receptor-mediated neurotransmission playing very important functions in physiological and pathological processes. This paper describes the development of an analytical procedure for the direct and simultaneous determination of free D-Asp, L-Asp and N-methyl D-Asp in specimens of different mouse brain tissues using chiral LC-MS/MS in Multiple Reaction Monitoring scan mode. After comparing three procedures and different buffers and extraction solvents, a simple preparation procedure was selected the analytes of extraction. The method was validated by analyzing L-Asp, D-Asp and N-methyl D-Asp recovery at different spiked concentrations (50, 100 and 200 pg/μl) yielding satisfactory recoveries (75-110%), and good repeatability. Limits of detection (LOD) resulted to be 0.52 pg/μl for D-Asp, 0.46 pg/μl for L-Asp and 0.54 pg/μl for NMDA, respectively. Limits of quantification (LOQ) were 1.57 pg/μl for D-Asp, 1.41 pg/μl for L-Asp and 1.64 pg/μl for NMDA, respectively. Different concentration levels were used for constructing the calibration curves which showed good linearity. The validated method was then successfully applied to the simultaneous detection of D-Asp, L-Asp and NMDA in mouse brain tissues. The concurrent, sensitive, fast, and reproducible measurement of these metabolites in brain tissues will be useful to correlate the amount of free D-Asp with relevant neurological processes, making the LC-MS/MS MRM method well suited, not only for research work but also for clinical analyses

PD-0283: 4D dose accumulation for dose painting by numbers for lung cancer

In conventional radiotherapy of locally advanced lung cancer (LALC) doses levels are homogeneously delivered to the entire PTV, whereat dose escalation is restricted by normal tissue toxicity. Several studies have shown the geometrical correlation between high FDG uptake in a PET scan and tumour recurrence. This is the rationale for FDG-based local dose escalation, e.g. by dose prescription on the voxel values of a PET scan – dose painting by numbers (DPBN). The aim of this study is to investigate the robustness of the DPBN plans against tumour motio

Editors, Publishers, Impact Factors, and Reprint Income

Harvey Marcovitch discusses new research findings from Andreas Lundh and colleagues that examined the effect of publishing industry-funded clinical trials on journal citations and reprint income at six major medical journals

Divergent behavior of hydrogen sulfide pools and of the sulfur metabolite lanthionine, a novel uremic toxin, in dialysis patients.

Dialysis patients display a high cardiovascular mortality, the causes of which are still not completely explained, but are related to uremic toxicity. Among uremic toxins, homocysteine and cysteine are both substrates of cystathionine β-synthase and cystathionine γ-lyase in hydrogen sulfide biosynthesis, leading to the formation of two sulfur metabolites, lanthionine and homolanthionine, considered stable indirect biomarkers of its production. Hydrogen sulfide is involved in the modulation of multiple pathophysiological responses. In uremia, we have demonstrated low plasma total hydrogen sulfide levels, due to reduced cystathionine γ-lyase expression. Plasma hydrogen sulfide levels were measured in hemodialysis patients and healthy controls with three different techniques in comparison, allowing to discern the different pools of this gas. The protein-bound (the one thought to be the most active) and acid-labile forms are significantly decreased, while homolanthionine, but especially lanthionine, accumulate in the blood of uremic patients. The hemodialysis regimen plays a role in determining sulfur compounds levels, and lanthionine is partially removed by a single dialysis session. Lanthionine inhibits hydrogen sulfide production in cell cultures under conditions comparable to in vivo ones. We therefore propose that lanthionine is a novel uremic toxin. The possible role of high lanthionine as a contributor to the genesis of hyperhomocysteinemia in uremia is discusse

Mild Endurance Exercise during Fasting Increases Gastrocnemius Muscle and Prefrontal Cortex Thyroid Hormone Levels through Differential BHB and BCAA-Mediated BDNF-mTOR Signaling in Rats

Mild endurance exercise has been shown to compensate for declined muscle quality and may positively affect the brain under conditions of energy restriction. Whether this involves brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) activation in relation to central and peripheral tissue levels of associated factors such as beta hydroxy butyrate (BHB), branched-chain amino acids (BCAA) and thyroid hormone (T3) has not been studied. Thus, a subset of male Wistar rats housed at thermoneutrality that were fed or fasted was submitted to 30-min-mild treadmill exercise bouts (five in total, twice daily, 15 m/min, 0◦ inclination) over a period of 66 h. Prefrontal cortex and gastrocnemius muscle BHB, BCAA, and thyroid hormone were measured by LC-MS/MS analysis and were related to BDNF and mammalian target of rapamycin (mTOR) signaling. In gastrocnemius muscle, mild endurance exercise during fasting maintained the fasting-induced elevated BHB levels and BDNF-CREB activity and unlocked the downstream Akt-mTORC1 pathway associated with increased tissue BCAA. Consequently, deiodinase 3 mRNA levels decreased whereas increased phosphorylation of the mTORC2 target FOXO1 was associated with increased deiodinase 2 mRNA levels, accounting for the increased T3 tissue levels. These events were related to increased expression of CREB and T3 target genes beneficial for muscle quality previously observed in this condition. In rat L6 myoblasts, BHB directly induced BDNF transcription and maturation. Mild endurance exercise during fasting did not increase prefrontal cortex BHB levels nor was BDNF activated, whereas increased leucine levels were associated with Akt-independent increased phosphorylation of the mTORC1 target P70S6K. The associated increased T3 levels modulated the expression of known T3-target genes involved in brain tissue maintenance. Our observation that mild endurance exercise modulates BDNF, mTOR and T3 during fasting provides molecular clues to explain the observed beneficial effects of mild endurance exercise in settings of energy restriction

Gestione sostenibile delle foreste Mediterranee e uso energetico delle biomasse forestali residuali

he book describes the reasons that led the Regional Department of Rural and Territorial Development to take part in the PROFORBIOMED Project. They can be summarized by the need to dispose of a tool for the sustainable management of all the state-owned forests of the Region. As a matter of fact, the Project aims at developing a model of sustainable forest management, through the recovery and reuse of wood scraps from ordinary silvicultural operations, to be used for the production of power and heat inside of a process adopting natural renewable energy sources. The main actions taken and the methodologies adopted are described, as well as the principles and instruments required for the setting up and execution of the work. Some of the most relevant are: the drafting of “Forest Management Plans”, the “Short Supply Chain” and the “Biomass Traceability Protocol”, together with the application of “Best Practices” of Management and the “Monitoring of impacts” caused by the woody biomass extraction procedures. The “forest – wood – energy” chain developed and proposed is exclusively related to the territory pertaining to one municipality, and with CHP plants fed with biomass exclusively produced within the territory of each municipality, in strict compliance with the “sustainable forest management” principles, as well as with the fundamental principle of “short supply chain”. For these reasons the CHP plans proposed shall be sized according to the biomass available in each municipality, with the possibility of integrating residual forest biomass with other waste wood resources potentially available in the territory and coming from prunings in agricultural activities. Therefore, the replicable model prepared and proposed by PROFORBIOMED aims at appraising from the economic point of view a waste product, such is currently considered the residual forest biomass from the forests of Sicily, and at the same time significantly improving the natural environment, thanks to the reduction in oil consumption