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The oxidation of ammonium sulfite obtained from ammonia-based flue gas desulfurization by hydrogen peroxide in aqueous solutions was studied using a stirred reactor. An experimental study of the kinetic parameters of the oxidation process was investigated in the pH of 4.2–5.2 at 25–50°C. $r = {k_3}\left[{{H^ + }} \right]\left[{HSO_3^ - } \right]\left[{{H_2}{O_2}} \right]$ r = k 3 H + HS O 3 − H 2 O 2 is valid at sulfite concentrations of 10−4 mol/L for the pH range 4.2–5.2. At 298K and pH of 5.0, third-order rate constant k3 was found to be (6.9 ± 0.21)×107 (mol/L)−2s−1. When the concentration of sulfite is 0.01 mol/L, the reaction first-order with respect to sulfite and hydrogen peroxide, and the second-order reaction rate constant at pH of 4.2–5.4 is $\lg {k_2} = - 1.0135pH + 7.4862$ lg k 2 = − 1.0135 pH + 7.4862. Activation energy of Ea = 32.26 kJ/moL. Kinetic data were compared with previous studies. A semi-empirical formula can express the effect of ionic strength on k3. The kinetic data of ammonium sulfite oxidation with hydrogen peroxide have potential applications in the wet ammonia desulfurization process. [ABSTRACT FROM AUTHOR]

This study firstly experimentally determined the performance of direct ammonia solid oxide fuel cell (DA-SOFC) under various O 2 -enriched cathode gas conditions at 750 °C and 700 °C. Results indicate a significant 40.4% decrease in DA-SOFC power density when temperature dropped from 750 °C to 700 °C, more pronounced than in H 2 –SOFCs. O 2 -enriched operation improved DA-SOFC power density, with increases ranging from 7.9% to 22.9% as O 2 molar fraction at the cathode inlet rose from 21% to 100% at 750 °C. And at 700 °C, such promoting effect on DA-SOFC was more significant than on H 2 –SOFC. Interestingly, DA-SOFC open circuit voltage (OCV) showed a nonmonotonic trend with increasing O 2 molar fraction, peaking between 30% and 60% O 2. Subsequently, multi-physics modeling of DA-SOFC were performed. The numerical results revealed that the observed increase in power density of DA-SOFC in O 2 -enriched operation mode was primarily resulted from the reduction in concentration polarization, rather than the changed OCVs/Nernst voltages. • Explanations of the factors controlling the enhancement of O 2 -enriched DA-SOFCs. • Identified and explained the nonlinear trend of OCV with increasing O 2. • Confirmed and quantified the impact of O 2 -enriched operation on DA-SOFCs. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in advanced packaging films made from natural polymers. These films are integrated with pH-sensitive dyes, aiming to monitor the freshness of food. Specifically, the development of pH-adaptive intelligent packaging films, known as MC5/ZA5-Anth3%, involves using methylcellulose (MC) and zinc alginate (ZA) as the foundational materials, with anthocyanins (Anth) serving as the freshness indicators. The production of MC5/ZA5-Anth3% films has resulted in improved thermal stability, mechanical properties and water resistance, alongside a reduction in the transmission of ultraviolet–visible (UV–vis) light through the material. Importantly, these color-changing films undergo a noticeable change in color when subjected to pH changes or exposure to ammonia gas, making them suitable for detecting shifts in the pH of foods like pork and shrimp, the presence of volatile nitrogen compounds, and early signs of food degradation. Upon exposure to varying pH buffers, the color indicator film underwent a noticeable transition from a reddish-pink hue to blue, ultimately shifting to blue-green. Consequently, this pH-sensitive color indicator film emerges as a viable candidate for the smart, real-time monitoring of freshness in perishable foods such as pork and shrimp. [ABSTRACT FROM AUTHOR]

Ammonia gas detection has garnered widespread attention in various fields, including food, environmental industries, and medical diagnostics. In this article, we present the synthesis of graphene-based tin oxide (graphene–SnO2) hybrid nanostructures using the hydrothermal method. Pristine tin oxide nanostructures and a series of graphene-based tin oxide hybrids containing 5 wt.%, 10 wt. %, 15 wt. %, and 20 wt. % graphene concentrations were fabricated to investigate their response as ammonia gas sensors. The X-ray diffraction and high-resolution transmission electron microscopy analysis revealed the tetragonal rutile crystal structure of both pristine SnO2 and graphene–SnO2 hybrid structures. The morphology of the synthesized structures was examined using scanning electron microscopy. Fourier transform infrared spectroscopy was employed to validate the functional groups present in the hybrid structures, while the band gap of the graphene–SnO2 nanohybrid structures was determined using diffuse reflectance spectroscopy. X-ray photoelectron spectroscopy was utilized to investigate the chemical composition, electronic state, and bonding of the materials. Four probe current–voltage (I–V) measurements were conducted to investigate conductivity and ammonia-sensing behavior. Upon exposure to ammonia gas fumes, the pristine SnO2 exhibited changes in current and resistance, ranging from 0.063 mA to 3.75 mA and 15.87 kΩ to 266.67 Ω, respectively. Similarly, the ammonia sensing behavior of hybrid structures containing 20 wt. % graphene showed changes in current and resistance, ranging from 5.42 mA to 37.8 mA and 0.18 kΩ to 26.45 Ω, respectively. These findings suggest that graphene–SnO2 hybrid structures exhibit excellent conductivity when exposed to NH3 gas, unlike their ammonia-absence counterparts. [ABSTRACT FROM AUTHOR]

Biological dinitrogen (N2) fixation, the energetically expensive conversion of N2 gas to ammonia, plays an essential role in balancing the nitrogen budget in the ocean. Accumulating studies show detectable N2 fixation rates below the euphotic zone in various marine systems, revealing new insights of marine N2 fixation. However, the reported rates are highly variable and frequently fall close to detection limits, raising the question of the ubiquity and significance of N2 fixation in the global dark ocean. Using highly sensitive isotopic labeling incubation including a set of control incubations, we confirm the occurrence of mesopelagic N2 fixation in the South China Sea. Interestingly, we consistently observed that ca. 30% of samples show a significant elevation of 15N in the particulate nitrogen after incubation at most depths (200 - 1000 m). Although this approach does not allow accurate quantification of N2 fixation rates, our data suggest the occurrence of dark N2 fixation yet with highly heterogeneous signals in the mesopelagic zone of the South China Sea. A data compilation of reported N2 fixation in the global dark ocean further reveals that such heterogeneity has also been observed elsewhere, unveiling the ubiquitous heterogeneity in mesopelagic N2 fixation. Thus, we call for more observations to constrain mesopelagic N2 fixation budgets and to understand the underlying mechanism for such heterogeneity. [ABSTRACT FROM AUTHOR]

Fireproof sealant is a common sealing material and has a wide range of applications, which has the dual performance of sealing and fireproof. To figure out its thermal degradation behavior, the thermogravimetric experiments combined with Fourier transform infrared technology were conducted at multiple heating rates. The results showed that the pyrolysis process could be separated into three stages and the explicit reaction equations were revealed corresponding to each stage: First, ammonium polyphosphate decomposed to produce a large amount of inorganic acid, along with a small amount of ammonia and water. Then, a large amount of ammonia gas was produced from melamine decomposition, and the substrate including acrylic resin began to react. Furthermore, the remaining base materials and intermediate carbonized materials continued to be decomposed to produce large amounts of carbon dioxide, water and residue. The experimental results indicated that the various components of fireproof sealant could cooperate closely and played a synergistic role in flame retardant, which could be an important reference value for guiding the improvement of fire sealing materials. [ABSTRACT FROM AUTHOR]

Graphene has emerged as one of the most promising materials for next‐generation gas sensor platforms due to its high flexibility, transparency, and hydrophobicity. However, graphene shows inherent low selectivity in gas sensing. This has led to extensive development of noble‐metal decoration on graphene to modulate its surface chemistry for enhanced selectivity. While noble metals such as Pt, Pd, and Au have widely been employed to functionalize graphene surface, non‐noble metal decoration of graphene has remained underexplored. Here, an unprecedented room‐temperature self‐activated graphene gas sensor functionalized by NiO nanoparticles and its application to wearable devices monitoring ammonia gas in daily life are demonstrated. NiO‐functionalized graphene micropatterns show ultra‐high selectivity to ammonia with a low detection limit of 2.547 ppt. Density functional theory (DFT) calculations reveal that the strong attraction between NiO and NH3 induced by charge depletion and the vertex region of NiO accelerate the adsorption of NH3 molecules. Furthermore, a wearable graphene device demonstrates the capability to detect ammonia emissions from beef, triggering an alarm call when a specific threshold is exceeded. This work proposes the functionalization of graphene with transition metal oxides, extending beyond the conventional noble metal decoration, and the potential utilization of the graphene for wearable devices. [ABSTRACT FROM AUTHOR]

In this study, delay line surface acoustic wave devices were prepared using a 128° Y-cut LiNbO3 piezoelectric substrate. Pure MoS2 and composite materials of MoS2 and SiO2 with various morphologies were sprayed to form sensitive layers. By adjusting the amount of NH4OH catalyst in the precursors, the particle sizes of SiO2 nanospheres were successfully controlled at 70, 200, and 300 nm by the sol-gel method. SiO2 nanospheres were then added to the precursor for preparing rosette-shaped MoS2, and nanocomposites were synthesized by the hydrothermal method. As a result, two types of composite material were obtained, namely, the S-M structure and the M-S structure. As ammonia gas sensors, the results showed that all the sensors exhibited negative frequency shifts as the NH3 gas concentration increased. Surface area and pore size distribution analyzer (BET) analysis showed that the highest specific surface area of 115.57 m²/g occurred on the S-M structural composite material. The sensor using the S-M structural composite material has a sensitivity of 1932 Hz/ppm to NH3 gas. The sensing linearity R-squared value is approximately 0.99, with continuous dynamic sensing at NH3 gas concentrations of 5-50 ppm. Finally, we revealed that decorating MoS2 with SiO2 nanospheres can improve the adsorption of ammonia molecules and significantly enhance sensitivity. [ABSTRACT FROM AUTHOR]

Due to the rapid dissolution of urea fertilisers in water, leaching and evaporation from the soil cause approximately 70 % of the urea to be lost to the atmosphere and groundwater without being used by plants. It is known that a significant portion of urea fertiliser is released into the atmosphere as ammonia gas, and into groundwater as nitrate and nitrite, resulting in nitrogen losses. To mitigate these losses, various studies have been conducted on coating urea fertiliser with different materials. Biopolymers, in addition to providing controlled release, also act as soil conditioners by increasing the water-holding capacity of the soil and providing necessary moisture to plants during dry periods. In this study, three different types of biopolymers – chitosan, pectin, and xanthan gum – at two different concentrations (1 % and 3 %), were used to coat urea fertiliser aiming for controlled release. Biopolymer solutions and their cross-linkers were prepared, and the urea fertiliser was coated using a laboratory-scale coating drum. The chemical structure of the coated urea fertiliser was determined using Fourier-Transform Infrared Spectroscopy, and its morphology was examined with a Scanning Electron Microscope. The water-holding capacity in the soil and the ammonia released into the atmosphere were also analysed. The results indicated that the most effective biopolymer coating type for the slow-release mechanism of urea was pectin at a 1 % coating ratio on the fertiliser granules. The concentration of ammonia released from the soil and the water-holding capacity of the soil treated with biopolymer-coated urea fertiliser were tested through various experiments, and the results were analysed statistically. According to the statistical analysis, the 1 % pectin-coated urea fertiliser yielded the best results in both experiments, with an ammonia release value of 246.66 ppm and an evaporation rate of 67.84 % at the end of 30 days. [ABSTRACT FROM AUTHOR]

Carbon-free ammonia is a promising hydrogen energy carrier. Using ammonia as gas turbine fuel can effectively reduce carbon emissions. This study examines thermoacoustic instabilities of partially premixed CH 4 /NH 3 flame in a laboratory-scale swirl burner. Results show that as α NH 3 increases from 0 to 20%, the co-firing flame switches from stable mode to medium-frequency oscillation mode (105.4–151.2Hz) and then to low-frequency oscillation mode (36.7–44.1Hz). The oscillation intensity first increases and then decreases. Increasing α NH 3 and combustion chamber length will expand the unstable Φ range and enhance the pressure and heat release pulsation. When α NH 3 = 20%, CO 2 emissions are reduced by 12.5%, while NO increases sharply to over 1000 ppm. The flame is more likely to induce the low-frequency oscillation at high Φ. The shorter combustor can mitigate thermoacoustic instability. • Thermoacoustic instability of partially premixed CH 4 /NH 3 flame are studied. • Thermoacoustic frequency decreases as NH 3 ratio and equivalence ratio increase. • Thermoacoustic effect is weaker in short combustion chambers. [ABSTRACT FROM AUTHOR]

The oxidation of ammonium sulfite must be inhibited to improve the economy and cycle performance of the ammonia flue gas desulfurization process. A stirred bubbling reactor was used to investigate the macrokinetics of oxidation inhibition of ammonium sulfite by sodium thiosulfate in wet ammonia desulfurization. The effects of initial SO32−${\rm SO}^{2-}_{3}$ concentration, Na2S2O3 concentration, pH value, gas flow rate, and temperature on the oxidation rate were discussed. The results show that the apparent activation energy of the reaction is 37.3 kJ/mol. The macrokinetics equation of sodium thiosulfate inhibiting sulfite oxidation in the ammonia desulfurization process was established. Combined with the kinetic model, it is inferred that the rate of sodium thiosulfate inhibiting ammonium sulfite oxidation is controlled by the intrinsic chemical reaction. The results can provide a reference for the regeneration of ammonium sulfite in the wet ammonia desulfurization process. [ABSTRACT FROM AUTHOR]

The MXene Ti3C2Tx was synthesized using hydrofluoric acid and an improved multilayer method in this study. Subsequently, a Bi2O3/Ti3C2Tx composite material was produced through hydrothermal synthesis. This composite boasts a unique layered structure, offering a large surface area that provides numerous contact and reaction sites, facilitating the adsorption of ammonia on its surface. The prepared Bi2O3/Ti3C2Tx-based sensor exhibits excellent sensing performance for ammonia gas, including high responsiveness, good repeatability, and rapid response–recovery time. The sensor's response to 100 ppm ammonia gas is 61%, which is 11.3 times and 1.6 times the response values of the Ti3C2Tx gas sensor and Bi2O3 gas sensor, with response/recovery times of 61 s/164 s at room temperature, respectively. Additionally, the gas sensitivity mechanism of the Bi2O3/Ti3C2Tx-based sensor was analyzed, and the gas sensing response mechanism was proposed. This study shows that the sensor can effectively enhance the accuracy and precision of ammonia detection at room temperature and has a wide range of application scenarios. [ABSTRACT FROM AUTHOR]

As ammonia continues to gain more and more interest as a promising hydrogen carrier compound, so does the electrochemical ammonia oxidation reaction (AmOR). To avoid the liberation of H2 in a reverse Haber–Bosch reaction under release of the energetically more favorable N2, we propose the oxidation of ammonia to value‐added nitrite (NO2−), which is usually obtained during the Ostwald process. We investigated the anodic oxidation of gaseous ammonia directly supplied to a gas diffusion electrode (GDE) using a variety of compositionally different multi‐metal catalysts coated on Ni foam under the simultaneous formation of H2 at the cathode. This will double the amount of H2 per ammonia molecule while applying a lower overpotential than that required for water electrolysis (1.4–1.8 V vs. RHE at 50 mA ⋅ cm−2). A selectivity study demonstrated that some of the catalyst compositions were able to produce significant amounts of NO2−, and further investigations using the most promising catalyst composition Nif_AlCoCrCuFe integrated within a GDE demonstrated up to 88 % Faradaic efficiency for NO2− at the anode coupled to close to 100 % Faradaic efficiency for the cathodic H2 production. [ABSTRACT FROM AUTHOR]

Ammonia, with its high hydrogen content, serves as an optimal carbon-free medium for indirect hydrogen storage, making it ideal for fuel cells. Nevertheless, the limited anodic catalytic activity of Proton-conducting solid oxide fuel cells (PCFCs) significantly hampers NH 3 utilization efficiency and overall performance. This study introduces efficient nano-catalysts deposited onto dendritic anodic microchannels, leading to the formation of an in-situ ammonia decomposition reactor for internal ammonia gas conversion. Compared to conventional cells, this cell, equipped with a catalyst bed, shows a 25% increase in peak power density and a 20%–30% enhancement in NH 3 utilization efficiency. Additionally, ammonia undergoes efficient decomposition on anodic metallic nickel, which prevents nickel nitridation and improves cell stability. The augmented stability of these cells is evidenced by their prolonged operational lifespan under constant current conditions, extending from 63 to 108 h, thus marking a substantial enhancement in the system's durability and reliability. • Ammonia is a storable, hydrogen-rich, carbon-free fuel highly compatible with PCFCs. • "Ammonia replace efficiency" characterizes ammonia fuel utilization rate in PCFCs. • Dendritic porous anode enables efficient catalyst loading for ammonia decomposition. • Ru-GDC fiber catalysts in porous anodes enhance catalytic reformer performance. [ABSTRACT FROM AUTHOR]

Ammonia gas is a colorless gas that is known for its pungent odor. It is commonly used in various industries, such as agriculture, refrigeration, and chemical manufacturing. This paper provides a comprehensive overview of various technologies employed in ammonia gas sensors. The objective is to compare and identify the optimum method to detect ammonia gas. The review encompasses catalytic gas sensors, metal oxide gas sensors, polymer conductivity gas sensors, optical gas sensors, and indirect gas sensors, detailing their respective operational principles. Additionally, the advantages and disadvantages of each technology for ammonia gas detection are outlined. All these technologies have been used for many applications and some of them have been commercialized. Some sensor characteristics suggestions are also stated in order to develop an improved optical ammonia sensor for industrial applications. [ABSTRACT FROM AUTHOR]

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia ( NH 3) at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of π – π interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH3. The study found that NH 4 is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with NH 4 molecules being ideal candidates for molecular doping of graphene. The H 2 O molecule can facilitate quick desorption by converting NH 3 to NH 4 . The interaction between graphene oxide and NH 3 molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and NH 3 molecules via π and lone pair electron network. The NH 3 -sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface. [ABSTRACT FROM AUTHOR]

Experiments on methylamine (CH3NH2${\rm CH}_3{\rm NH}_2$) decomposition in shock tubes, flow reactors, and batch reactors have been re‐examined to improve the understanding of hydrocarbon/amine interactions and constrain rate constants for CHx${\rm CH}_{ x}$ + NHy${\rm NH}_{ y}$ reactions. In high‐temperature shock tube experiments, the rapid thermal dissociation of CH3NH2${\rm CH}_3{\rm NH}_2$ provides a fairly clean source of CH3${\rm CH}_3$ and NH2${\rm NH}_2$ radicals, allowing an assessment of reactions of CH3${\rm CH}_3$ with NH2${\rm NH}_2$ and NH. At the lower temperatures in batch and flow reactors, CH3NH2${\rm CH}_3{\rm NH}_2$ is mostly consumed by reaction with H to form CH2NH2${\rm CH}_2{\rm NH}_2$ + H2${\rm H}_2$; these results are useful in determining the fate of the CH2NH2${\rm CH}_2{\rm NH}_2$ radical. Interpretation of these data, along with flow reactor data for the CH3NH2${\rm CH}_3{\rm NH}_2$/H system at lower temperature, indicates that at temperatures up to about 1400 K at atmospheric pressure and above 2000 K at 100 atm, the CH3${\rm CH}_3$ + NH2${\rm NH}_2$ reaction forms mainly methylamine. At sufficiently high temperature, H‐abstraction to form CH4${\rm CH}_4$ + NH and addition–elimination to form CH2NH2${\rm CH}_2{\rm NH}_2$ + H become competitive. The CH3${\rm CH}_3$ + NH reaction, with a rate constant close to collision frequency, forms CH2NH${\rm CH}_2{\rm NH}$ + H, also leading into the hydrocarbon amine pool. Thus, methylamine can be expected to be an important intermediate in co‐combustion of natural gas and ammonia, and more work on the chemistry of CH3NH2${\rm CH}_3{\rm NH}_2$ is desirable. [ABSTRACT FROM AUTHOR]

Novel sensing applications benefit from multifunctional nanomaterials responsive to various external stimuli such as mechanics, electricity, light, humidity, or pollution. While few such materials occur naturally, the careful design of synergized nanomaterials unifies the cross-coupled properties which are weak or absent in single-phase materials. In this study, 2D MoS2 integrated with ultrathin dielectric oxide layers forms hetero-nanostructures with significant impacts on carrier transport. The ternary TiO2/MoS2/ZnO hetero-nanostructures, along with their individual properties, improve the performance of multifunctional sensing devices. The synthesized hetero-nanostructure exhibits a responsivity of up to 16 mA/W to 700 nm light and responds to 5 ppm ammonia gas at room temperature. These enhancements are attributed to interface charge transfer and photogating effects. The ternary TiO2/MoS2/ZnO hetero-nanostructure is compatible with existing semiconductor fabrication technologies, making it feasible to integrate into flexible, lightweight semiconductor devices and circuits. These results may inspire new photodetectors and sensing devices based on two-dimensional (2D) layered materials for IoT applications. [ABSTRACT FROM AUTHOR]

The high specific surface area of graphene is an important factor to enable a large molecular adsorption on the surface, thus enabling direct sensing on a versatile surface. A large area graphene sensor (1 cm2) is fabricated using a transfer method for the detection of ammonia (NH3) gas under ambient conditions. The ambient atmosphere contains 21% oxygen (O2), and thus it is crucial to understand its impact on the sensing of ammonia gas. The sensing response is analyzed under both the inert nitrogen (N2) gas and condensed dry air (CDA) containing 78.08% N2, 20.95% of O2, and 0.93% of argon gas. Upon interaction with the graphene, both NH3 and O2 resulted in opposite electrical responses. Thus, this finding reveals a polarity dependent interaction of gases with the graphene. [ABSTRACT FROM AUTHOR]

Excessive nitrogen (N) deposition affects aquatic ecosystems worldwide, but effectiveness of emissions controls and their impact on water pollution remains uncertain. In this modeling study, we assess historical and future N deposition trends in Chinese river basins and their contributions to water pollution via direct and indirect N deposition (the latter referring to transport of N to water from N deposited on land). The control of acid gas emissions (i.e., nitrogen oxides and sulfur dioxide) has had limited effectiveness in reducing total N deposition, with notable contributions from agricultural reduced N deposition. Despite increasing controls on acid gas emissions between 2011 and 2019, N inputs to rivers increased by 3%, primarily through indirect deposition. Simultaneously controlling acid gas and ammonia emissions could reduce N deposition and water inputs by 56 and 47%, respectively, by 2050 compared to 2019. Our findings underscore the importance of agricultural ammonia mitigation in protecting water bodies. [ABSTRACT FROM AUTHOR]

The early detection and treatment of Helicobacter pylori infections can help prevent the formation of ulcers and development of gastric cancer in humans. The urea breath test (UBT) is a noninvasive test for diagnosing H. pylori. However, isotopic‐labeled UBT reagents are expensive and require specialized test equipment to detect isotopic CO2. In this study, the development of a user‐friendly, cost‐effective, and alternative method for diagnosing H. pylori infections by detecting NH3 in exhaled breath is reported. A commercial disposable pH strip is modified with sodium carboxymethylcellulose to enhance its performance in gaseous environments. The modified pH strip exhibits compatibility with both acidic (HCl and CH3COOH) and alkaline (NH3) gases. Furthermore, the sensor monitors the production of NH3 resulting from fish spoilage for 72 h, highlighting its real‐time capabilities. The feasibility of employing this simple strip sensor to detect H. pylori infection in patients is investigated through in vitro experiments and preliminary clinical studies. The simple strip sensor is a promising alternative to the C‐13 UBT for detecting H. pylori infection. [ABSTRACT FROM AUTHOR]

This research aimed to quantify concentrations of ammonia (NH3), carbon dioxide (CO2) and methane (CH4), estimate emissions, and analyze the factors influencing them during warm periods in an open dairy barn equipped with two cooling systems in a Mediterranean climate zone. Gas distribution within the barn was observed to vary both vertically and horizontally, with the highest gas concentrations observed in the central area of the barn. NH3, CH4 and CO2 ranged in 1.7--7.4, 7--18, 560--724 μg·g-1, respectively. Natural ventilation through openings and the operation of cooling systems induced changes in indoor microclimate conditions, influencing cow behavior and, consequently, gas production. Gas concentrations were the highest at air velocities below 0.5 m·s-1humidity index (THI) was > 72 and ≤ 78; and CO2 and CH4 concentrations were the highest with THI ≥ 72 and decreased with THI ≤ 72. NH3 concentrations when barn management included three daily milkings were higher than those measured when barn management was based on two daily milkings, and lower for CH4 and CO2. NH3 and CH4 emissions were the highest during barn cleaning, while the lowest NH3 emissions occurred during activity of the cows (i.e., feeding, walking). [ABSTRACT FROM AUTHOR]

In this study, the characteristics of ammonia and their effects on secondary particulate matter (PM) formation were analyzed by region in Korea in 2020. The NH3 concentration was high in GJ (11.4 ppb), a neighboring agricultural area, followed by DJ (9.0 ppb) and SE (8.6 ppb), which are located in urban areas. On the other hand, BI (2.6 ppb) and JI (4.5 ppb), which are background regions, demonstrated a lower concentration than other areas. Seasonally, ammonia was high in spring and summer, and it generally increased when human activities are active. Therefore, it is believed that the ammonia in the atmosphere not only changes depending on local emissions, but also based on temperature-dependent phase distribution characteristics. For SE and GJ, regions with relatively high ammonia concentrations, investigations into the effect of ammonia on secondary PM formation were conducted. In both regions, the ammonium-to-sulfate mole ratio tended to increase with increasing ammonia or PM2.5 concentration. It can be assumed that the PM2.5 concentration increases as nitrates are formed under the ammonia-sufficient condition. The adjusted gas ratio is generally greater than 4, indicating that there is a lot of free ammonia. Thus, it is estimated that a reduction in ammonia would not be effective to restrain nitrate formation. [ABSTRACT FROM AUTHOR]

This study delineates the mycotoxin-producing capabilities of Rhizopus microsporus strains isolated from stored grains and nuts. Aflatoxins, particularly aflatoxin B1, are significant due to their deleterious effects on human and animal health and their economic impact on vital agricultural commodities. Employing polymerase chain reaction (PCR) for identification, one isolate was confirmed to produce aflatoxin B1 and was associated with R. microsporus. Thin-layer chromatography (TLC) and ammonia gas tests substantiated the isolate's toxin-producing ability. High-performance liquid chromatography (HPLC) quantified aflatoxin B1 concentration, revealing a yield of 395.19 PPb. This study's findings are unprecedented, marking the first known instance of such isolates producing toxins globally. DNA extraction from fungal hyphae, PCR analysis, nucleotide sequencing, and submission to the National Center for Biotechnology Information (NCBI) database further corroborated the isolate's classification as R. microsporus. The isolate was formally registered in the Gene Bank with serial number OP205376.1, representing a notable contribution to Iraqi and international scientific communities. [ABSTRACT FROM AUTHOR]

Ammonia, recognized as a perilous compound for both environmental and human health, necessitates detection of its varied concentrations in the air for environmental conservation and safety. This study introduces a novel self-powered ammonia gas sensor, operating at room temperature using a chitosan and tin dioxide (SnO₂) composite film. Designed based on the galvanic cell principle, the sensor eliminates the need for external power sources, making it ideal for various environmental and industrial applications. Advanced morphological and compositional analyses were conducted through field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDAX), confirming the effective integration of SnO₂ into the chitosan matrix, enhancing surface oxygen content and porosity. Fourier transform infrared (FTIR) spectroscopy revealed NH₂ groups in chitosan that interact with ammonia gas. The sensor demonstrated exceptional sensitivity and selectivity towards ammonia, with peak sensitivity reaching 26.13% at 50 ppm, significantly higher than pure chitosan's 17.14%. The sensor showed a substantial increase in electrical voltage in response to ammonia, effectively distinguishing it from gases such as acetone, ethanol, and toluene. This superior performance is attributed to the interaction between ammonia and NH₂ groups in chitosan, which promotes the release of trapped electrons. This research marks a significant advancement in gas detection technology, offering an eco-friendly, efficient, and reliable method for ammonia monitoring, essential for environmental protection and industrial safety. [ABSTRACT FROM AUTHOR]

Ammonia detection is crucial for various applications such as environmental monitoring, industrial processes, and healthcare. Here, we explore the potential of La-doped ZnO thin films as a cost-effective, efficient, and environmentally friendly RT-NH3 sensor prepared by spray pyrolysis method. Pure and La-doped ZnO films were highly sensitive and selective to ammonia gas as compared to other gases. The 3% La-doped ZnO films were most sensitive to ammonia gas with a relatively high response of about 74.28%, with very fast response time and recovery time of 17 s and 30 s, respectively, at room temperature. The response of 3% La-doped ZnO thin films was about three times greater than that of the pure ZnO films when evaluated under the same conditions. Moreover, the selectivity, sensitivity, reproducibility and long-term stability were also examined. The 3% La-doped ZnO films show a gas-sensing response at a lower concentration of 0.5 ppm of ammonia. [ABSTRACT FROM AUTHOR]

The current investigation aims to develop a validated numerical model of a confined, swirl-stabilized diffusion flame. This model will assist in designing and optimizing novel combustion chambers while reducing computational costs. To achieve this objective, experimental and numerical studies were conducted on NH3/natural gas combustion using a laboratory-scale burner capable of operating under fuel-flexible conditions. The burner fired 5 kW flames of blended ammonia with natural gas in concentrations up to 100% NH3. The burner's performance for relevant industrial applications was assessed through measurements of axial temperature profiles, exhaust temperature, and gas emissions. Numerical simulations were conducted by employing the commercial CFD software STAR-CCM+ 2020.2.1. Numerical simulations for steady-state were performed using a realizable k- ϵ turbulence model coupled with the EDC (eddy dissipation concept) for combustion. The investigation utilized a 3D periodic domain for the simulations and investigated mesh independence and the influence of the flame dynamics. The burner was able to operate with different fuel mixtures while maintaining stabilized flames under every condition. However, the appearance of increased ammonia slip was observed for 100% NH3 up to 1250 ppm (dry vol.). The present work demonstrates and assesses the readiness and potential of fuel-flexible burners as cost-effective and efficient transitional technologies for integrating ammonia and other sustainable fuels into combustion applications. [ABSTRACT FROM AUTHOR]

Rayon is an extremely valuable cellulosic fiber in the global textile industry. Since cuprammonium rayon is more eco-friendly than other types of rayon fabrics, it was synthesized by regenerating α–cellulose isolated from wastepaper using a novel gaseous-ammoniation injection (GAI) process. This was achieved by preparing tetra–ammine copper hydroxide (cuoxam solution) via reacting copper sulfate and sodium hydroxide to produce copper hydroxide that was, finally, ammoniated by injecting the gas directly to the reaction vessel instead of using ammonium hydroxide applied by prior art. After that, the air-dried cellulose was chemically generated by dissolving it in a freshly prepared cuoxam solution and, subsequently, was regenerated by extruding it within a hardening bath constituted mainly from citric acid, producing the cuprammonium rayon (c. rayon). The properties of the fibrous, structural (XRD and mechanical), physical, and chemical features were investigated. It was found that the rayon was produced in a high yield (90.3%) with accepted properties. The fibrous properties of the rayon staple length, linear density, and fiber diameter were found to be 44 mm, 235 Tex, and 19.4 µm, respectively. In addition, the mechanical properties determined, namely tensile strength, elongation at break, modulus of elasticity, and breaking tenacity, were found to be 218.3 MPa, 14.3 GPa, 16.1%, and 27.53 cN/Tex, respectively. Based on this finding, and upon injecting the ammonia gas through the α–cellulose saturated and immersed in the Cu (OH)2 to complete producing the cuoxam solvent, we find that theuse of an injection rate of 120 mL/minute to obtain the highest fibers' tensile strength for the final product of the c. rayon is preferable. Utilization of higher rates will consume more amounts of the ammonia gas without gaining noticeable enhancement in the c. rayon's mechanical quality. Accordingly, the GAI invention rendered the c. rayon favorable for use in making sustainable semisynthetic floss for either insulation purposes or spun threads for woven and nonwoven textile clothing. [ABSTRACT FROM AUTHOR]

The current study describes the excellent sensing properties of zinc oxide samples with varying La doping concentrations (1, 3, and 5 %). The X-ray diffraction (XRD) study suggests that the produced ZnO samples exhibit hexagonal structure. Due to varying concentrations of La, a notable difference in the morphological image of the samples was observed using a Field Emission Scanning Electron Microscope (FESEM). The existence of La, Zn, and O elements in the sample was analyzed by Energy Dispersive X-Ray Analysis (EDX). The Fourier Transform Infrared Spectroscopy (FTIR) studies validate the sample's structure and functional group. The UV–Vis results showed that the maximum optical reflectance of 90 % was attained in the visible region and the obtained band gap values for the samples were in the range of 3.27–3.33 eV. At ambient temperature, the La-doped samples demonstrated high sensitivity towards ammonia (NH 3) and had the highest response value of 1940 % for the 250 ppm. According to the results, an excellent operating stability, and response/recovery time were obtained for the ZnO:La1% sample which suggests that the sample can serve as the most appropriate metal oxide for the detection of NH 3 at room temperature. [ABSTRACT FROM AUTHOR]

This paper demonstrates design and simulation of an acoustic wave resonator-based ammonia gas sensor which is resonating at ∼ 3.95 GHz resonant frequency. The bulk acoustic wave-based solidly mounted resonators (SMRs) are robust, simple to manufacture, miniaturized and most suitable for high sensitivity gas sensors. The designed sensor consists of multilayer stack of (Si/SiO2/BR/Mo/ZnO/Mo/rGO) thin films. Here, reduced graphene oxide (rGO) is utilized as an ammonia gas-sensing layer and zinc oxide (ZnO) as piezoelectric layer. Bragg reflector (BR) is applied to confine the acoustic wave. The simulated sensor is based on the resonant frequency shift due to mass loading effect by adsorbed ammonia gas molecules. The amount of frequency shift depends on the concentration of ammonia gas. The ammonia gas sensor results in sensitivity (S) of 7.113 MHz pg−1 with outstanding selectivity over other exposed gases to the sensor. The SMR-based ammonia gas sensor is designed using air tight gas chamber and gases are exposed to the sensor in controlled ambient. In addition, the number of BR pairs (Mo/SiO2) is also optimized for optimal performance of sensor, using transfer matrix model. The simulated ammonia gas sensor is small in size, highly sensitive and can find applications in safety and environmental monitoring in various industries, including chemical plants, refrigeration systems and agricultural applications. [ABSTRACT FROM AUTHOR]

We report a unique combination of three components in the form of a ternary nanocomposite, PANI/CD/SnO2, for ammonia gas sensing at room temperature. This nanocomposite was synthesized via in situ chemical oxidative polymerization of aniline, in which other components were incorporated to form binary PANI/CD and ternary PANI/CD/SnO2 nanocomposites. The fabrication process initially involved optimization of the PANI/CD nanocomposite and then incorporation of an optimized amount of SnO2 to finally produce the ternary PANI/CD/SnO2 nanocomposite. The ternary composite demonstrated better sensing properties than those of both PANI/CD (1:0.5) and pristine PANI in terms of sensitivity, selectivity, and response time over a concentration range of 5–100 ppm NH3. The response of the PANI/CD/SnO2 nanocomposite was 21.6% towards 100 ppm NH3, which was higher than that of pure PANI and the PANI/CD nanocomposite. The ternary composite exhibited higher selectivity for ammonia over other gases as compared to PANI and the PANI/CD (1:0.5) nanocomposite. The PANI/CD/SnO2 composite also achieved a shorter response time (94 s) than pure PANI (162 s) and the PANI/CD (144 s) composite, and it demonstrated a nearly linear variation in response with the analyte concentration. High repeatability and long-term stability further enhanced the possibility of real-world application of the proposed ternary nanocomposite for practical room-temperature ammonia sensing. [ABSTRACT FROM AUTHOR]

Current ammonia sensors exhibit cross-sensitivity to water vapor, leading to false alarms. We developed a core–shell nanofiber (CSNF) structure to address these issues, using conductive poly(3,4-ethylenedioxythiophene) (PEDOT) as the core and hydrophobic polyvinylidene fluoride-tetrafluoroethylene (PVDF-TrFE) as the shell. The PEDOT-PVDF CSNF, with a diameter of ~500 nm and a 300 nm thick PVDF layer, showed a superior sensitivity and humidity resistance compared to conventional PEDOT membranes for ammonia concentrations of 10–100 ppm. In humid environments, CSNF sensors outperformed membrane sensors, exhibiting a tenfold increase in performance at 51% relative humidity (RH). This study highlights the potential of CSNF sensors for practical ammonia detection, maintaining a high performance under varying humidity levels. [ABSTRACT FROM AUTHOR]

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Highlights: Exploiting single-atom catalytic activation and targeted adsorption properties, Ni single-atom active sites based on N, C coordination are constructed on the surface of two-dimensional MXene nanosheets (Ni–N–C/Ti3C2Tx), enabling highly sensitive and selective NH3 gas detection. The catalytic activation effect of Ni–N–C/Ti3C2Tx effectively reduces the Gibbs free energy of the sensing elemental reaction, while its electronic structure promotes the spill-over effect of reactive oxygen species at the gas–solid interface. An end-sealing passivation strategy utilizing a conjugated hydrogen bond network of the conductive polymer was employed on MXene-based flexible electrodes, effectively mitigating the oxidative degradation of MXene-based gas sensors. Significant challenges are posed by the limitations of gas sensing mechanisms for trace-level detection of ammonia (NH3). In this study, we propose to exploit single-atom catalytic activation and targeted adsorption properties to achieve highly sensitive and selective NH3 gas detection. Specifically, Ni single-atom active sites based on N, C coordination (Ni–N–C) were interfacially confined on the surface of two-dimensional (2D) MXene nanosheets (Ni–N–C/Ti3C2Tx), and a fully flexible gas sensor (MNPE–Ni–N–C/Ti3C2Tx) was integrated. The sensor demonstrates a remarkable response value to 5 ppm NH3 (27.3%), excellent selectivity for NH3, and a low theoretical detection limit of 12.1 ppb. Simulation analysis by density functional calculation reveals that the Ni single-atom center with N, C coordination exhibits specific targeted adsorption properties for NH3. Additionally, its catalytic activation effect effectively reduces the Gibbs free energy of the sensing elemental reaction, while its electronic structure promotes the spill-over effect of reactive oxygen species at the gas–solid interface. The sensor has a dual-channel sensing mechanism of both chemical and electronic sensitization, which facilitates efficient electron transfer to the 2D MXene conductive network, resulting in the formation of the NH3 gas molecule sensing signal. Furthermore, the passivation of MXene edge defects by a conjugated hydrogen bond network enhances the long-term stability of MXene-based electrodes under high humidity conditions. This work achieves highly sensitive room-temperature NH3 gas detection based on the catalytic mechanism of Ni single-atom active center with N, C coordination, which provides a novel gas sensing mechanism for room-temperature trace gas detection research. [ABSTRACT FROM AUTHOR]

MXene Ti3C2T x (30% HF-etched, named Ti3C2T x -30) plays a pivotal role in the substantial enhancement of the structural modification of molybdenum trioxide (MoO3). Additionally, as the surface MoO3 molecules come into contact with reducing gas moieties, they actively participate in gas sensing at room temperature. The percentage of Ti3C2T x -30 in the MoO3 matrix was varied at 10%, 20%, and 40%, denoted as MM-10, MM-20, and MM-40, respectively. Structural analysis confirmed the composition of the basic elements and evolution of TiO2 at a higher percentage of Ti3C2T x -30. Spectroscopy analysis showed the interactions between Ti3C2T x -30 and MoO3, showcasing work functions of 6.91 eV, 6.75 eV, and 7.21 eV for MM-10, MM-20, and MM-40, respectively, confirming MM-20 to be an optimum composition. When the samples were exposed to ammonia gas, MM-20 showed a high response (93% for 100 ppm) at room temperature, with a response time of ∼10 s. Compared to bare MoO3, these samples showed ten-fold improvement. The excess electrons on the surface of Ti3C2T x -30 facilitate the formation of O2− species, which also provides stability to the otherwise highly reactive MXene surface. These species actively react with ammonia molecules in the presence of adsorbed MoO3, thereby changing the resistance of the system. This can be a significant step towards imparting high gas sensitivity to metal oxides at room temperature via incorporation of an optimum percentage of optimized Ti3C2T x. [ABSTRACT FROM AUTHOR]

Ammonia becomes one of the indispensable raw materials in production and life, with the continuous development of industry. Ammonia pollution of the environment is becoming more and more serious, so the adsorption of ammonia is essential. In this paper, a new biochar material based on tannic acid was developed. The tannic acid was self-polymerized using different activators (K2CO3, KHCO3, KOH). Tannic acid biochar (TAB-X) was obtained by pyrolytic carbonization reaction at 800 ℃. The biochar was treated with phosphoric acid 10% by mass (TAB-X-10%PO4), and unlike other biochar materials, the specific surface area and hydroxyl content were increased after acidification, but there were no acidic functional groups. It is noteworthy that the specific surface area of TAB-KOH increased from 22 m2/g to 667 m2/g after acidification. The adsorption capacity of ammonia vapor reached 342.6 mg/g. It is proposed that the adsorption mechanism is an adsorption process in which hydroxyl groups on the surface of TAB-X firstly adsorb water, and after that ammonia gas is then dissolved in the water molecules on the surface of the biochar. These results highlight the great potential of TAB as an adsorbent for the adsorption of ammonia, in addition to the low price of raw materials and the simple preparation conditions of this preparation process, which corresponds with the conditions for mass production as well as practical application. [ABSTRACT FROM AUTHOR]

This study involved depositing thin films of copper oxide (CuO) and copper oxide films incorporated with neodymium oxide (Nd2O3) in various weight ratios using the pulsed laser deposition technique to fabricate an ammonia gas sensor. The characteristics of the developed films were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence spectroscopy (PL) techniques. The study investigated the impact of incorporating Nd2O3 into the CuO film on its sensing characteristics. The X-ray analysis revealed a polycrystalline structure of CuO with a crystal size of 19 nanometers. Furthermore, incorporating CuO and Nd2O3 formed a mixed phase comprised of both CuO and Nd2O3. The average crystallite size varied with the Nd2O3 incorporation rate from 19nm to 14.7nm. With increasing Nd2O3 incorporation ratios, the surface morphology changed from smooth to spherical-like nanostructures, and the average particle sizes varied from 28nm to 130nm. The PL spectrum analysis results confirmed that the incorporation of Nd2O3 resulted in a change in the peak intensity of the PL spectrum, with a significant increase in the peak associated with oxygen vacancies, contributing to the improvement of the sensor response. The incorporation of Nd2O3 greatly enhanced the sensitivity of the as-deposited CuO film. The sample with 5 wt.% Nd2O3 exhibited the maximum sensitivity, reaching 180% against 79 ppm NH3 at a working temperature of 50∘C. [ABSTRACT FROM AUTHOR]

Here we report a facile method of functionalization of single-walled carbon nanotubes (SWNTs) with polypyrrole and making a chemiresistive sensor using the functionalized nanomaterial for sub-part-per-million detection of ammonia gas at room temperature. The sensor fabrication involves three steps: (i) immobilization of SWNTs by dip coating method on a silane-treated silicon/silicon dioxide substrate, (ii) printing of two parallel lines of conducting silver paste 5 mm apart as source and drain to define the source and the drain electrode, and (iii) in-situ electrochemical polymerization to functionalize the SWNTs with polypyrrole. The functionalization of SWNT was confirmed using electrochemical current-voltage measurements. The functionalized SWNTs exhibited several folds higher sensitivity to ammonia gas than the pristine SWNTs. A charge density of 0.85 C.cm−2 was optimum for electrochemical functionalization, providing maximum sensing response toward ammonia. The functionalized SWNTs showed a large measurable response starting from 50 to 750 part-per-billion (ppb) of ammonia with a sensitivity of ∼1.55% per ppb, and a limit of detection of 5 ppb of ammonia. Almost complete recovery of the sensor and an average response time of ∼9 min was also observed. [ABSTRACT FROM AUTHOR]

In situ synthesis of aluminum nitride (AlN)-reinforced magnesium alloy composites using ammonia (NH3) gas was investigated. Feasibility of in situ formation of AlN reinforcement was analyzed based on Gibbs energy minimization method. Thermodynamic analysis showed that AlN forms in Mg–Al alloy in the temperature range from 923 K to 1223 K and the oxygen that may be present in the system was detrimental for the formation of nitrides. The thermodynamic analysis also shows that Mg aids in decreasing the oxygen content from the system. Injecting ammonia gas through Mg alloy caused bulk nitridation of the alloy, which led to the formation of AlN-reinforced Mg alloy composites. Presence of hydrogen, which was generated by the dissociation of ammonia, in the alloy getters the trace oxygen in the gaseous precursor, enabling the formation of AlN. For the ammonia injection through the Mg–Al alloy containing 30 wt pct Al at 1173 K and injection time of 70 minutes, the yield of AlN was found to increase with an increase in the flow rate of ammonia. The AlN formed in the melt was 15.42 wt pct AlN for a gas flow rate of 0.04 LPM (liters per minute), and 27.43 wt pct AlN at a flow rate of 0.1 LPM. AlN particles formed in situ are surrounded by the γ-(Mg, Al) phase. X-ray diffraction characterization showed that the composites formed in situ were composed of (Mg), intermetallic γ-(Mg, Al), and AlN phases. Scanning electron microscopy and optical microscopy analyses revealed that the AlN particles formed in situ, dispersed uniformly, and the increase in flow rate increases the dispersion density of AlN particles in the composites. The experimental compositions and phases obtained are included in the constructed Mg–Al–N ternary phase diagram at 1173 K. All experimental data fall in the region of AlN and Mg–Al alloy, which is in validation with the thermodynamic prediction. The experimental obtained amount of AlN in composites as a function of Al content in alloy are in good agreement with the thermodynamic modeled results, which indicates that the formation of AlN in Mg–Al alloy is close to an equilibrium process. [ABSTRACT FROM AUTHOR]

A pH‐sensitive protein fibre membrane was prepared using alizarin (ALI), curcumin (CUR), gelatin, zein and cinnamaldehyde as raw materials, by electrospinning technology. The membrane was developed to detect food deterioration and extend shelf life. It was observed that the addition of CUR significantly enhanced the antioxidant and barrier properties of the membrane. The fibre membrane was responsive to pH with minimal colour alteration in response to humidity (from 20% to 80% relative humidity) and demonstrated excellent reusability along with a low detection limit for ammonia gas. Moreover, it was capable of monitoring low concentrations of bacteria in the headspace. To assess the efficacy of the membrane, a freshness monitoring and preservation study was carried out on pork stored at 4°C for 5 days. The fibre membrane not only prolonged the shelf life of meat but also allowed real‐time monitoring of its freshness. The results highlight the potential application of the prepared nanofibres in the simultaneous monitoring and preservation of meat freshness. [ABSTRACT FROM AUTHOR]

The effect of nonlinear dynamic shock waves on perovskite BaTiO 3 nanoparticles (NPs) is investigated using a table top pressure-driven shock tube (Reddy Tube) for ammonia gas sensing applications with the Mach number of 2.2. In general, shock waves are a nonlinear high-pressure phenomenon characterized by high dynamic pressure and temperature. Raman and powder X-ray diffraction (XRD) methods were utilized to evaluate the molecular and structural characteristics of the BaTiO 3 (BTO) NPs under the influence of dynamic shock waves. The surface absorption was assessed using UV- diffuse reflectance spectroscopy (UV-DRS). XRD data shows that BaTiO 3 NPs crystallized in tetragonal crystal structure with P 4 mm space group and stable throughout the shocks, without undergoing any phase change. The average particle size of the control BaTiO 3 was 31 nm, while those of shocked BaTiO 3 were 62 nm (100 shocks) and 55 nm (200 shocks), demonstrating the significant change in morphology and showing that particles have irregular spherical morphology and are agglomerated by shock wave loaded conditions. Moreover, BaTiO 3 nanoparticles were shocked after being tested with various concentrations of different gases at a temperature of 200°C. Under shock loaded conditions, the heightened sensing response for ammonia gases was between 5 and 20 ppm; also, sensing properties such as sensitivity, response, and recovery time indicated that BaTiO 3 nanoparticles are a good potential ammonia gas sensing material for real-time sensor applications with enhanced characteristics. [ABSTRACT FROM AUTHOR]

Hydrogen and ammonia are playing an increasingly vital role in combustion technologies. Recently, some detailed reaction mechanisms (DRMs) can predict reliable laminar burning velocities (LBVs). Meanwhile, despite their broad applicability in practical combustion engineering, global reaction mechanisms (GRMs) suitable for ammonia and its mixtures with hydrogen or nitrogen have yet to be reported. This study aims to address this gap by investigating new GRMs. Five DRMs were used to calculate the LBVs, and their average values were employed as a reference. First, a single-step GRM was developed for hydrogen (H 2 + 0.5O 2 → H 2 O), and another single-step GRM was developed for ammonia (NH 3 + 0.75O 2 → 0.5N 2 + 1.5H 2 O). However, their combined GRM did not provide reasonable predictions of LBVs for the H 2 +NH 3 mixtures. Therefore, a 4-step GRM was developed consisting of the single-step hydrogen and three additional reactions, i.e., an endothermic ammonia decomposition (NH 3 + 0.5O 2 → NO + 3H), an exothermic NO reduction (NO + 2H → 0.5N 2 + H 2 O), and an exothermic H recombination (H + H → H 2). In conclusion, this 4-step GRM and its revisions could predict reasonable LBVs, flame temperatures, and primary product compositions for mixtures of hydrogen, ammonia, and cracked ammonia gas over a wide range of temperatures (300–600 K) and pressures (1–5 atm). • Global reaction mechanisms (GRMs) were investigated for H 2 +NH 3 +N 2 mixtures. • Laminar burning velocities (LBVs) from the detailed reaction mechanisms were compared. • Single-step GRMs were improved for the individual fuels H 2 and NH 3. • Available ranges were extended in temperatures (300–600 K) and pressures (1–5 atm). [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of valorizing corn straw as an alternative feed for fattening calves by treating it with ammonia gas. Different levels of ammonia gas (AG) (0, 2, 3, and 4%) were injected into bags containing moistened corn straw. The plastic bags were stored at 20-25 °C for one month. The results showed that corn straw processed with 4% AG, compared to other experimental treatments, increased the amount of protein (P<0.05). Corn straw treated with 3% AG increased the amount of ether extract compared to the untreated group (P<0.05). Corn straw processed with 3% and 4% AG reduced acid detergent fiber (ADF) (P<0.05). Corn straw treated with 4% AG reduced neutral detergent fiber (NDF) compared to the control group. Additionally, the NDF of corn straw was reduced by using a 3% level of AG (P<0.05). Corn straw treated with 4% AG significantly improved the digestibility of organic matter (% DOM), digestibility of organic matter in dry matter (% DOMD), and metabolizable energy (ME) (P<0.05). Corn straw treated with 4% AG increased gas production at 6, 12, 48, and 72 hours of incubation, but no significant difference was observed at 24 and 36 hours of incubation. Nutritional parameters results of gas production (digestibility of organic matter (OMD), ME, and short-chain fatty acids (SCFA) were not affected by processing with ammonia gas. The highest feed intake was recorded with processed corn straw at 9.108 kg, while the feed conversion ratio remained stable, indicating no significant improvement in weight gain efficiency. Total feed costs were lowest for calves without corn straw at $176.320, with minimal increases for unprocessed and processed corn straw options, highlighting the economic considerations of incorporating corn straw into feeding strategies. In general, it can be concluded that treating corn straw with 4% ammonia gas improves its nutritional value by enhancing protein content and digestibility. Despite the increased feed intake, feed conversion efficiency remained unchanged, suggesting economic advantages in calf feeding strategies. [ABSTRACT FROM AUTHOR]

The current scientific literature predominantly focuses on pilot-scale studies concerning the effectiveness of membrane covers in reducing gas emissions during cattle manure composting. Our study centers on the application of a leading market commercial membrane cover (ePTE-TEXcomm) and a locally manufactured one (ProfiCover®) at industrial processing levels, evaluating their efficacy in mitigating gas emission during the fifth day of the thermophilic phase. Taking into account material inhomogeneities, work environment impact, and efficiency, the results are characteristic of industrial-scale processes rarely discussed in the scientific literature. Our results, obtained with a portable gas sampler and FTIR spectroscopy measurements using corresponding standards, indicate that ePTE-TEXcomm manifested a reduction of 90.8% for NH3 and 59.6% for CO2. CH4 emissions increased, suggesting their potential entrapment. N2O and propane equivalent experienced reductions of 23.1% and 44.8%, respectively. On the other hand, ProfiCover® presented emission reductions for NH3 and CO2 of 93.3% and 85.9%, respectively. CH4, contrasting with ePTE-TEXcomm, showed a significant reduction of 55.6%. N2O and propane equivalent followed with reductions of 56.7% and 84.5%, respectively. All of this divergence in performance implies a potential trade-off in emission reduction efficacy between the covers. Knowledge sharing between researchers and industry partners is key to translating these technologies into widespread adoption. [ABSTRACT FROM AUTHOR]

Industrialization and agricultural demand have both improved human life and led to environmental contamination. Especially the discharge of a lot of poisonous and harmful gases, including ammonia, ammonia pollution has become a pressing problem. High concentrations of ammonia can pose significant threats to both the environment and human health. Therefore, accurate monitoring and detection of ammonia gas are crucial. To address this challenge, we have developed an ammonia gas sensor using In(OH)3/Ti3C2Tx nanocomposites through an in-situ electrostatic self-assembly process. This sensor was thoroughly characterized using advanced techniques like XRD, XPS, BET, and TEM. In our tests, the I/M-2 sensor exhibited remarkable performance, achieving a 16.8% response to 100 ppm NH3 at room temperature, which is a 3.5-fold improvement over the pure Ti3C2Tx MXene sensor. Moreover, it provides swift response time (20 s), high response to low NH3 concentrations (≤ 10 ppm), and excellent long-term stability (30 days). These exceptional characteristics indicate the immense potential of our In(OH)3/Ti3C2Tx gas sensor in ammonia detection. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Industry / Hemijska Industrija is the property of Association of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)