Gas Humidity Research Articles

The Hydrates of TEMPO: Water Vibrations Reveal Radical Microsolvation.

An organic radical monohydrate complex is detected in vacuum isolation at low temperature by FTIR supersonic jet spectroscopy for the first time. It is shown to exhibit a rich conformational and vibrational coupling dynamics, which can be drastically reduced by appropriate isotope substitution. Its detection with a new gas recycling infrared spectrometer demonstrates the thermal metastability of the gaseous TEMPO radical even under humid gas conditions. Compared to its almost isoelectronic and isostructural, closed shell ketone analogue, the hydrogen bond of the solvating water is found to be less directional, but stronger and more strongly downshifting the bonded water OH stretch vibration. A second solvent water directs the first one into a metastable hydrogen bond position to solvate the nitrogen center and the first water at the same time.

The Hydrates of TEMPO: Water Vibrations Reveal Radical Microsolvation

AbstractAn organic radical monohydrate complex is detected in vacuum isolation at low temperature by FTIR supersonic jet spectroscopy for the first time. It is shown to exhibit a rich conformational and vibrational coupling dynamics, which can be drastically reduced by appropriate isotope substitution. Its detection with a new gas recycling infrared spectrometer demonstrates the thermal metastability of the gaseous TEMPO radical even under humid gas conditions. Compared to its almost isoelectronic and isostructural, closed shell ketone analogue, the hydrogen bond of the solvating water is found to be less directional, but stronger and more strongly downshifting the bonded water OH stretch vibration. A second solvent water directs the first one into a metastable hydrogen bond position to solvate the nitrogen center and the first water at the same time.

Numerical Study on Biogas Refining System Combined with Proton-Conducting Solid Oxide Electrolyzer

Biogas is one of the most globally distributed carbon-neutral fuels to be used as a local biomass energy source for local society energy demand. However, since the biogas from organic waste is typically a mixture of 60% methane and 40% carbon dioxide, the biogas has a lower energy density compared with coal, oil, LNG, and etc. In this study, biogas refining system including methanation reactor and proton-conducting electrolysis cell has been proposed and investigated based on the numerical calculation including mass and heat balance analysis. Using this system, hydrogen and CO2 derived from electrolysis cell and biogas, respectively, will be converted into methane via methanation reaction. Carbon deposition is a well-known problem to be resolved when carbon-rich gas is supplied to the cell cathode. Based on the calculation results, the gas humidification was found to be necessary to prevent carbon deposition at the cathode inlet. However, carbon deposition was predicted to still occur at the cathode outlet even with the gas humidification when a conventional oxide-ion conducting electrolyte is applied to the electrolysis cell due to the enhanced carbon activity caused by oxide-ion transport from the cathode to the anode. In the case of the proton-conducting electrolyte, proton transport from the anode to the cathode was found to mainly promote reverse water-gas shift reaction and methanation reaction without any carbon deposition. Even though the calculation results should be verified by comparing with experimental results, the numerical study suggested that the biogas refining system combined with p-SOEC is a promising technology for generating carbon-neutral methane with a strongly suppressed risk of carbon deposition.

Promotion of Hydrogen Oxidation and Methane Dry Reforming Over Ni-SDC Anode by Basic Oxide Additives

Direct internal reforming of hydrocarbon fuels on the anodes of solid oxide fuel cells (SOFCs) leads to an increase in power generation efficiency, and consequently numerous investigations have been done on this topic. Among hydrocarbon fuels, methane is a primary target fuel because it is a major component of natural gas. Steam and CO2 are adopted as a reforming reagent for a direct internal reforming SOFC. Direct reforming of methane with CO2 (dry reforming of methane, DRM) offers better power generation efficiency [1] and a compact system without a steam generator. In addition, a mixture of CH4 and CO2 is available as biogas, and therefore the applicability of SOFCs is expanded to biomass-derived energy resources. However, DRM will suffer from more severe coking than steam reforming of methane. Recently we reported calcium-modified Ni-SDC cermet anodes for DRM [2]. The addition of Ca to Ni-SDC anodes improved the activity for methane reforming by CO2 and suppressed carbon deposition on the anode, leading to superior durability of the anode in direct DRM operation. In this study, we further investigated the effect of additives such as MgO, BaO, and Cr2O3 on hydrogen oxidation and DRM on the anode.SDC powders were prepared by the co-precipitation method. The desired amount of Ce(NO3)3∙H2O and Sm(NO3)3∙6H2O (Wako Pure Chemical Industries) were mixed with oxalic acid to form co-precipitate, which was successively dried, and then calcined at 1000˚C for 2 h and 1500˚C for 5 h in air. The obtained SDC powder was mixed with NiO at the desired ratio, followed by calcination at 1300˚C for 5 h in air. As a cathode material, La0.6Sr0.4MnO3- d (LSM) was prepared [3]. As for the NiO-SDC anode preparation with additives, the anode was fabricated by infiltrating the pristine NiO-SDC anode with the respective nitrate solutions, followed by calcination at 1200˚C for 2 h in air. As the additives, Mg, Ca, Ba, and Cr were examined. Before power generation tests, the anode was exposed to H2 flow at 1000˚C to reduce NiO to Ni. The power generation performance of the cells was evaluated by current-voltage characteristics at 1000, 900, 800, 700˚C with SP-300 (Bio-Logic SAS, France), by feeding 0.3% humidified H2 or DRM gas on the anode side. Alternative current (AC) impedance spectroscopy in humidified H2 flow was conducted under open circuit condition before and after the power generation tests on direct DRM operation to evaluate the durability of the cells. The outlet gas composition analysis was also carried out in DRM power generation experiments by an on-line micro gas chromatograph (Varian, CP-4900).The power generation characteristics at 900˚C by feeding humidified hydrogen and a mixture of methane and CO2 are shown in Fig. 1(a) and (b), respectively. When humidified hydrogen was used, IV characteristics were improved by adding the basic and amphoteric elements to the Ni-SDC anode. The open circuit voltage (OCV) was identical to that of the pristine Ni-SDC, irrespective of the additives, whereas the current density was increased, especially by the addition of magnesium. Impedance analysis revealed that the polarization resistance of hydrogen oxidation was decreased by the additives. This result indicates that the oxidation reaction of hydrogen on the anode was promoted by the additives. Among the additives, MgO was found to be the most effective at reducing the polarization resistance of hydrogen oxidation. In the case of the power generation with DRM shown in Fig. 1(b), the MgO addition increased the current density from 0.49 A cm-2 on the pristine anode to 0.61 A cm-2 at 0.70 V, while the other additives exhibited almost no effect on IV. Nevertheless, OCV varies depending on the additives, which indicates the difference in the activity for CO2 reforming of methane. Higher conversion of methane and CO2 should lead to a decrease in oxygen partial pressure at the anode side, and consequently to the increase in OCV. The anode outlet gas analysis by GC under open circuit condition exposed that CH4 conversion was raised over the modified anodes; namely, the methane dry reforming reaction was promoted by the additives. It is also noteworthy that the carbon balance over the modified anodes was ±2% while the balance over the pristine anode was at -13%.

Numerical Modeling and Parametric Study of the Melting Behavior of Ice Crystal Particles

Ice crystal icing has been identified as a risk to flight safety, due to its ability to reduce engine performance and its potential to cause engine damage and flameout. A critical factor in the sticking efficiency of ice crystals is the melting behavior of ice crystals. This paper presents an ice melting model integrated with surface blowing and porosity. A parametric study is performed to understand the effects of flow conditions (total pressure, humidity, total temperature, Mach number, and slip velocity) and particle properties (particle size, aspect ratio, and porosity factor) on ice melting behavior. The model is compared against the melting time of single ice particles in an acoustic levitator. The results show that employing sphericity and porosity could improve prediction performance. Surface blowing from evaporation increases melting time, and its effect is larger with a higher gas temperature. Ice melting time increases with pressure at high humidity, whereas an opposite trend is observed at low humidity. Increasing gas temperature, humidity, slip velocity, aspect ratio, and particle temperature can decrease ice melting time, whereas increasing Mach number, particle size, and porosity factor can increase ice melting time. Although wet bulb temperature can be used to evaluate ice melting potential when only one flow parameter is varied, it appears insufficient alone under scenarios where multiple flow parameters are changing simultaneously.

High-Flow Nasal Cannula for Patients with Acute Respiratory Failure Treated in a General Medical Ward: A Prospective Cohort Study

Background: Hypoxemia and the need for oxygen administration are frequent causes of hospital admission. High-flow nasal cannula (HFNC) delivers heated humidified high-flow gas at an adjustable inspired oxygen fraction via a large-bore nasal cannula and provide specific physiological benefits. The efficacy of HFNC has been investigated in the intensive care unit but data in other care settings are scarce, especially in low- and middle-income countries. Objective: To describe the safety and associated clinical outcomes of HFNC used in patients admitted to general medical wards. Materials and Methods: The present study was a prospective cohort study that enrolled adult patients with acute respiratory failure and no other major organ failures admitted to the general medical wards at Siriraj Hospital in Bangkok and treated with HFNC. Enrolled subjects were managed by a multidisciplinary care team trained in HFNC usage. The primary outcome was to determine the rate of HFNC failure, defined as the subsequent need for endotracheal intubation, non-invasive ventilation (NIV), reintubation, or death within 48 hours. Secondary outcomes included determining the in-hospital mortality, 28-day mortality, and the factors associated with HFNC failure. Results: Seventy-one subjects were enrolled. In these patients, acute de novo hypoxemic respiratory failure was the most common indication for HFNC (42.3%), followed by prophylaxis after extubation (38.0%), and cardiogenic pulmonary edema (19.7%). The overall rate of HFNC failure was 25.4%. The overall in-hospital and 28-day mortality rates were 14.1% and 21.1%, respectively. The only factor associated with HFNC failure was the respiratory rate at day 1. Conclusion: The use of HFNC in general medical wards is feasible, but a 25% rate of failure within 48 hours can be expected. A higher respiratory rate at day 1 is associated with the failure of HFNC. Keywords: Acute respiratory failure; General medical ward; High-flow oxygen therapy; Outcomes; Safety

Development of integrated technology for waste heat recovery from humid flue gas of hot water boiler

For coal-fired hot water boilers, we developed a comprehensive waste heat recovery system coupled with a packed tower, industrial steam turbine, and absorption heat pump, which can directly reduce the auxiliary power consumption, realize energy cascade utilization, and waste heat recovery. The ASPEN Plus software was used to simulate the packed tower, absorption heat pump, and industrial steam turbine system. The design parameters of the system were obtained and the operation characteristics of the system under load rates of 25%, 50%, 75%, and 100% were investigated, the feasibility of steam subsystem transformation was also analyzed. Taking a 140 MW coal-fired boiler as an example, in the range of 25%~100% load rate, the direct energy saving can reach 118 to 523 kW∙h, the waste heat recovery power is 2.7 to 11.4 MW, and the coal saving can reach 374 to 1605 kg/h, resulting in energy and resource consumption reduction effect, the system also has CO2 and pollutant emission reduction effect. The RadFrac model can be used in packed tower design, the system can work well under variable load conditions.

Numerical Study on Biogas Refining System Combined with Proton-Conducting Solid Oxide Electrolyzer

Biogas refining system including methanation reactor and proton-conducting electrolysis cell has been proposed and investigated based on the simulation including mass and heat balance analysis. Based on the calculation results, carbon deposition was predicted to still occur at the cathode outlet even with the gas humidification when a conventional oxide-ion conducting electrolyte is applied to the electrolysis cell due to the enhanced carbon activity caused by oxide-ion transport from the cathode to the anode. In the case of the proton-conducting electrolyte applied solid oxide electrolysis cell, proton transport from the anode to the cathode was found to mainly promote reverse water-gas shift reaction and methanation reaction without any carbon deposition. Even though the calculation results should be verified by comparing with experimental results, the numerical study suggested that the biogas refining system combined with p-SOEC is a promising technology for generating carbon-neutral methane with a strongly suppressed risk of carbon deposition.

IoT-powered system for environmental conditions monitoring in poultry house: A case of Tanzania

Poultry health is imperative for the continued growth of poultry and increased production. Environmental conditions such as temperature, humidity, and ammonia gas have an impact on poultry health. They affect the respiratory system and eventually cause death. In Tanzania, most smallholder farmers use charcoal and kerosene stoves to control the environmental parameters since they have limited access to low-cost, secure, and user-friendly poultry house monitoring systems. However, these traditional methods are unreliable, difficult to manage, not environmentally friendly, and inaccurate. Data were collected from 120 poultry farmers in Arusha and Kilimanjaro regions using convenience and snowball sampling techniques. Of the respondents, 43% revealed that smallholder farmers do not adopt automated systems despite being available because they are expensive. In this study, a system based on the Internet of Things (IoT) was developed for environmental conditions monitoring in poultry houses for low-resourced smallholder farmers in Tanzania. The system saves time (84%) and labour costs (66.7%) compared to the traditional system, as the farmer can monitor and control the conditions securely, reliably, and remotely. The study also proposes an algorithm for the system to work online and offline (i.e.,, synchronizing with the cloud server when internet access is available).

Mechanisms of gas temperature variation of the atmospheric microwave plasma torch

The gas temperature is a key parameter that affects the process of microwave plasma chemistry in industrial applications. Based on the molecular emission spectrometry of the A2Σ+→X2Πr electronic system of OH radicals, the gas temperature of the atmospheric air microwave plasma core at different absorbed microwave power levels, gas flow rates, gas humidities, and volume fractions of CO2 in air was analyzed. In the experiment, the absorbed microwave power, gas flow rate, gas humidity, and volume ratio of CO2 in air was varied from 560 to 1750 W, 10 to 24 l min−1, 30% to 95%, and 0% to 40%, respectively. Moreover, the axial gas temperature distribution of the plasma torch was measured. The experimental results showed that (i) the plasma gas temperature mainly ranged from 4000 to 7000 K, (ii) the plasma gas temperature rose with increasing absorbed microwave power but was hardly affected by the feeding gas flow rate, (iii) the plasma gas temperature decreased by ∼400 K for every 20% increase in the fraction of CO2 in air and decreased with increasing gas humidity, and (iv) the plasma torch gas temperature decreased along the axial direction. Due to the lack of a prevailing microwave discharge theory, an in-depth analysis of the mechanisms of gas temperature variation was performed based on the heat balance equation.

The Effect of Pollutant Gases on Surfactant Migration in Acrylic Emulsion Films: A Comparative Study and Preliminary Evaluation of Surface Cleaning.

From their first employment in the 1950s, acrylic emulsions have remained widely used as art material today. Although under certain deteriorating conditions they are very stable, if exposed to high humidity and atmospheric pollutant gases, their structural and chemical conformation is strongly affected. Dealing with the resulting surfactant migration, various cleaning treatments were considered over the years. However, their choice remains difficult as they easily alter the acrylic component, especially if in contact with aqueous solutions. The present study focuses on investigating the stability of acrylic emulsion films exposed to accelerated aging by various pollutant gases. Firstly, a comparative analytical study was carried out in order to morphologically (by 3D optical and Atomic Force Microscopy) and chemically (by Raman and Infrared spectroscopy) characterize the reactions and degradation products. Subsequently, two water-based cleaning treatments were tested, and a preliminary evaluation of their cleaning effectiveness was performed. The results show that the reaction of atmospheric gas pollutants with water molecules in moisture leads to acidic reaction products that attack the acrylic matrix and favor the migration of the surfactant to the surface. The effectiveness of cleaning treatments depends on the aging conditions applied, which further lead to different surface morphological changes.

Comparison of minimal-flow sevoflurane versus desflurane anesthesia: randomized clinical trial

Background and objectivesMinimal-flow anesthesia provides various advantages, such as reduced environmental pollution, proper humidification and warming of anesthetic gases, and reduced costs. The aim of this study was to compare the cost-effectiveness of minimal-flow sevoflurane and desflurane anesthesia and their effects on hemodynamics, postoperative recovery, respiratory parameters, and liver and kidney functions. MethodsA total of 60 ASA I–II patients aged 18–70 years who underwent posterior spinal instrumentation were included in the study. The patients were divided into Group S (sevoflurane) and Group D (desflurane). After anesthesia induction, the gas flow was initiated at a rate of 4 L.min-1 using a concentration of 8% in Group D and 3.5% in Group S, and the time to reach 0.8 MAC was recorded. The gas flow was then switched to minimal flow. Patient hemodynamic and respiratory parameters, body temperatures and arterial blood gas levels were recorded. The integrated pulmonary index (IPI) was monitored postoperatively. Biochemical findings were recorded 12 hours after the operation. The amount of bleeding and blood transfused, and the costs involved were calculated. ResultsThe patients’ demographic characteristics, duration of surgery, hemodynamic parameters, IPI values, body temperatures, and arterial blood gas levels were similar at all time points. Biochemical findings, amount of bleeding and amount of blood transfused were similar between the two groups. The mean cost was lower in Group S than in Group D (p = 0.007). ConclusionThe study found no significant difference in terms of reliability between minimal-flow sevoflurane and desflurane anesthesia. Furthermore, the procedure was found to be more cost-effective for Group S than for Group D.

Experimental study on the removal of PM2.5 using modified carbon steel collectors with hydrophilic properties in wet ESPs

Along with the increasingly stringent dust emission concentration standards for the thermal power plants and the challenge of market competition, wet electrostatic precipitators (ESPs) have been widely used as terminal equipment for the flue gas treatment. The wet ESPs pilot test platform using the modified carbon steel collectors with hydrophilic properties was established in this paper and the experimental research on PM2.5 removal characteristics were carried out. The mechanism of the particles removal efficiency enhancement by water film on the surface of modified collectors was studied. The effect of gas temperature, residence time, working voltage, inlet concentration and flushing water flowrate on the particles removal efficiency was investigated. The results indicated that the fibrous layer over the surface of the modified collectors could reduce the effect of the airflow recoil and the electromigration resistance of particles. The surface of the modified collectors could also maintain a uniform and stable water film with a lower amount of water consumption. The water film could restrain the back corona and the re-entrainment of dust. And the evaporation of water film increased the humidity of the flue gas, meanwhile, the particles charge capacity and electromigration velocity increased. Those all could improve the particles removal efficiency. The particles removal efficiency increased with the increase of the flue gas residence time and the applied voltage, but the particles removal efficiency improved less with the increase of the particles inlet concentration and flushing water flow rate after maintaining uniform and stable water film. The modified rigid collector provided high removal efficiency for particles with diameters of 0.04～0.48 μm under lower energy and water consumption. Implications: The wet electrostatic precipitators (ESPs) have been widely used as terminal equipment of the flue gas treatment to purify the flue gas deeply. The surface of the modified carbon steel collectors with hydrophilic properties could maintain a uniform and stable water film with a lower amount of water consumption. The evaporation of water film improved the particle charge capacity and electromigration velocity. The wet ESPs using the modified rigid collector exhibited significantly higher removal efficiency of particles than using the conventional rigid collector especially to the particles with diameter of 0.04～0.48 μm.

Non-thermal plasma in honeycomb catalyst for the high-throughput removal of dilute styrene from air

This study focused on the removal of styrene using a metal-coated monolith (MCM) catalyst integrated with non-thermal plasma. The MCM catalyst was prepared by depositing a ZSM-5 support impregnated with a combination of three metals (Co, Pd, La) on a practical-scale honeycomb monolith. A comparative study with a commercial metal-coated monolith (CMCM) of the same dimensions was conducted to evaluate the effectiveness of the MCM with respect to styrene removal. The plasma discharge in the monolith was characterized by measuring the voltage and current waveforms and optical emission spectroscopy (OES). The electric power of the plasma discharge largely depended on the metal loading, flow rate, and humidity of the feed gas. The removal efficiency of styrene (inlet concentration: 20 parts per million, volumetric (ppm)) was examined using both plasma catalytic oxidation (PCO) and thermal catalytic oxidation (TCO), to enable the effect of plasma to be clearly assessed. PCO with the MCM catalyst achieved styrene removal efficiency of nearly 100% at a specific energy input (SEI) of 40 J/L, whereas the CMCM catalyst achieved 92% removal for identical SEI. In comparison, TCO with the MCM and CMCM catalysts required high temperatures of 420 °C and 480 °C, respectively, for the complete removal of styrene. In addition, the CO2 selectivity of the MCM catalyst was higher at 83% compared with 75% for the CMCM at SEI of 40 J/L. The optimal silica binder content for the deposition of a robust washcoat layer was found to be approximately 5%.

(Invited) Electrochemical Detection of Gases in Ionic Liquids in Different Humidity Environments

Amperometric gas sensors (AGSs) are widely used due to their many advantages, such as low-cost, portability, durability, wide linear range, high sensitivity and high selectivity [1]. They are available commercially from a number of companies [2], and can detect a range of redox-active gases. The sensor devices typically employ a water/sulfuric acid mixture as the electrolyte in contact with three electrodes, covered by a gas-permeable membrane. Room temperature ionic liquids (RTILs) have strong potential for use as alternative ‘designer solvents’ in membrane-free AGSs [3], which would solve the existing technological problems of commercial AGSs, including the slow diffusion through the membrane and solvent evaporation. Their non-volatility would enable the membrane to be dispensed with, and the entire sensor to be miniaturised to provide optimal functionality over a much wider range of ambient conditions and with a longer lifespan. This allows and encourages innovative designs, with the potential for gas sensors to move from single, finite devices to more sophisticated systems that exploit recent advances in portable electronics and computing.In this talk, I will discuss some of the challenges facing ionic-liquid based sensors, such as solvent leakage, sensitivity to moisture and accumulation of electrogenerated products, and how we can innovatively design electrode materials and electrolytes to overcome these challenges. In particular, I will show that the choice of ionic liquid is crucial in high humidity gas environments, due to the structuring and layering of the ions in the electrical double layer [4]. Overall, it is clear that RTILs show tremendous promise as electrolytes in sensors, but more understanding of their long-term operation and utility in real environments is still needed.

A hybrid electrochemical flow reactor to couple H2 oxidation to NADH regeneration for biochemical reactions

AbstractBeta‐nicotinamide adenine dinucleotide (NAD+/NADH) is an important enzymatic co‐factor that can be efficiently regenerated using a rhodium‐based catalyst as electron transfer mediator (ie, [Cp*Rh(bpy)Cl]+, where Cp* = pentamethylcyclopentadienyl and bpy = 2,2‐bipyridine). Here, the above mediated regeneration of NADH is implemented in a redox flow bioreactor hybridized with a gas diffusion electrode for hydrogen oxidation. The reactor was initially optimized with respect to rhodium complex and NAD+ concentrations, humidification of the hydrogen gas, flow rates of both H2 gas and electrolytic solution, and solution pH. The integration of an enzymatic reaction consuming the generated NADH was then investigated in a flow process, combining in series the electrochemical reactor to a biochemical cell with immobilized l‐lactic dehydrogenase for the conversion of pyruvate to lactate. A high activity was achieved with a turnover number up to 370 h−1 for NADH regeneration. Coupled electrochemical regeneration to enzymatic reaction led to total turnover number values of 2000 and 6.3 × 106 for NADH electrochemical regeneration and bioconversion, respectively.

The IDEAL household energy dataset, electricity, gas, contextual sensor data and survey data for 255 UK homes

The IDEAL household energy dataset described here comprises electricity, gas and contextual data from 255 UK homes over a 23-month period ending in June 2018, with a mean participation duration of 286 days. Sensors gathered 1-second electricity data, pulse-level gas data, 12-second temperature, humidity and light data for each room, and 12-second temperature data from boiler pipes for central heating and hot water. 39 homes also included plug-level monitoring of selected electrical appliances, real-power measurement of mains electricity and key sub-circuits, and more detailed temperature monitoring of gas- and heat-using equipment, including radiators and taps. Survey data included occupant demographics, values, attitudes and self-reported energy awareness, household income, energy tariffs, and building, room and appliance characteristics. Linked secondary data comprises weather and level of urbanisation. The data is provided in comma-separated format with a custom-built API to facilitate usage, and has been cleaned and documented. The data has a wide range of applications, including investigating energy demand patterns and drivers, modelling building performance, and undertaking Non-Intrusive Load Monitoring research.

Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements

Water management is a key factor affecting the efficiency of proton exchange membrane fuel cells (PEMFCs). The currently used monitoring methods of PEMFCs provide limited information about which processes or components that humidity has a significant impact upon. Herein, we propose the use of a novel approach of impedance measurements using a multi-sinusoidal perturbation signal, which enables impedance measurements under dynamic operating conditions. The manuscript presents the effect of the relative humidity (RH) of the reactants on the instantaneous impedance of the middle cell in the PEMFC stack as a function of the current load. Analysis of changes in the values of equivalent circuit elements was carried out to determine which process determines the stack’s performance depending on the load range of the fuel cell during operation. Comprehensive impedance analysis showed that to ensure optimal cell operation, the humidity of the reactants should be adjusted depending on the load level. The results showed that at low-current loads, the humidity of gases should be at least 50%, while at high-current loads, the cell should operate optimally at a gas humidity of 30% or lower. The presented methodology provides an important tool for optimizing and monitoring the operation of fuel cells.

Delivery Room Interventions for Hypothermia in Preterm Neonates

Prevention of hypothermia in the delivery room is a cost-effective, high-impact intervention to reduce neonatal mortality, especially in preterm neonates. Several interventions for preventing hypothermia in the delivery room exist, of which the most beneficial is currently unknown. To identify the delivery room thermal care intervention that can best reduce neonatal hypothermia and improve clinical outcomes for preterm neonates born at 36 weeks' gestation or less. MEDLINE, the Cochrane Central Register of Controlled Trials, Embase, and CINAHL databases were searched from inception to November 5, 2020. Randomized and quasi-randomized clinical trials of thermal care interventions in the delivery room for preterm neonates were included. Peer-reviewed abstracts and studies published in non-English language were also included. Data from the included trials were extracted in duplicate using a structured proforma. A network meta-analysis with bayesian random-effects model was used for data synthesis. Primary outcomes were core body temperature and incidence of moderate to severe hypothermia on admission or within the first 2 hours of life. Secondary outcomes were incidence of hyperthermia, major brain injury, and mortality before discharge. The 9 thermal interventions evaluated were (1) plastic bag or plastic wrap covering the torso and limbs with the head uncovered or covered with a cloth cap; (2) plastic cap covering the head; (3) skin-to-skin contact; (4) thermal mattress; (5) plastic bag or plastic wrap with a plastic cap; (6) plastic bag or plastic wrap along with use of a thermal mattress; (7) plastic bag or plastic wrap along with heated humidified gas for resuscitation or for initiating respiratory support in the delivery room; (8) plastic bag or plastic wrap along with an incubator for transporting from the delivery room; and (9) routine care, including drying and covering the body with warm blankets, with or without a cloth cap. Of the 6154 titles and abstracts screened, 34 studies that enrolled 3688 neonates were analyzed. Compared with routine care alone, plastic bag or wrap with a thermal mattress (mean difference [MD], 0.98 °C; 95% credible interval [CrI], 0.60-1.36 °C), plastic cap (MD, 0.83 °C; 95% CrI, 0.28-1.38 °C), plastic bag or wrap with heated humidified respiratory gas (MD, 0.76 °C; 95% CrI, 0.38-1.15 °C), plastic bag or wrap with a plastic cap (MD, 0.62 °C; 95% CrI, 0.37-0.88 °C), thermal mattress (MD, 0.62 °C; 95% CrI, 0.33-0.93 °C), and plastic bag or wrap (MD, 0.56 °C; 95% CrI, 0.44-0.69 °C) were associated with greater core body temperature. Certainty of evidence was moderate for 5 interventions and low for plastic bag or wrap with a thermal mattress. When compared with routine care alone, a plastic bag or wrap with heated humidified respiratory gas was associated with less risk of major brain injury (risk ratio, 0.23; 95% CrI, 0.03-0.67; moderate certainty of evidence) and a plastic bag or wrap with a plastic cap was associated with decreased risk of mortality (risk ratio, 0.19; 95% CrI, 0.02-0.66; low certainty of evidence). Results of this study indicate that most thermal care interventions in the delivery room for preterm neonates were associated with improved core body temperature (with moderate certainty of evidence). Specifically, use of a plastic bag or wrap with a plastic cap or with heated humidified gas was associated with lower risk of major brain injury and mortality (with low to moderate certainty of evidence).

Water and steam injection in micro gas turbine supplied by hydrogen enriched fuels: Numerical investigation and performance analysis

This paper investigates the energetic and environmental performance of micro gas turbine plant with two proposed concurrent improvements: the methane-based fuel enriched by hydrogen and the humidification of the plant cycle. The energetic and environmental benefits of both features are well-know, and the aim of this work is the analysis of their combined impact on the micro gas turbine operation. Despite enhancing fuel with H2 involves significant advantages like greenhouse emission reduction and a better combustion in case of low LHV fuels, most of commercial micro gas turbine combustors are not able to burn fuels with high hydrogen content unless structurally modified. On the contrary, has been demonstrated that humidified gas turbines (i.e., gas turbines with water injection, humid air turbine (HAT) and steam injection gas turbine (STIG) cycles) improve the combustion stability as well as electric power delivered and plant efficiency. Hence, in order to investigate the feasibility of the concurrent two features, the first step of this work was the thermodynamic analysis of a micro gas turbine supplied by methane-based fuels enriched with H2 up to 20%vol, considering both dry and humidified cycles. Since a combustion anomaly was detected, i.e., flashback, in the CFD study on the combustion chamber, a steam injection in the combustor has been added in the plant layout with the aim of overcoming the anomaly, and its effect on the combustion process has been analyzed also raising the hydrogen content up to 30%vol. The main outcome of this paper is the assessment of the feasibility of supplying the combustor of the proposed HGT-STIG micro gas turbine with a hydrogen enrichment up to 30%vol, achieving a safe and regular combustion mainly owing to a steam injection mass flow equal up to 125% of fuel flow.