Gas Release as an Efficient Strategy to Tune Mechanical Properties and Thermoresponsiveness of Dynamic Molecular Crystals.

Dynamic molecular crystals combining multiple and finely tunable functionalities are attracting and an increasing attention due to their potential applications in a broad range of fields as efficient energy transducers and stimuli-responsive materials. In this context, a multicomponent organic salt, piperazinium trifluoroacetate (PZTFA), endowed with an unusual multidimensional responsive landscape is reported. Crystals of the salt undergo smooth plastic deformation under mechanical stress and thermo-induced jumping. Furthermore, via controlled crystal bending and release of trifluoroacetic acid from the lattice, which is anticipated from the design of the material, both the mechanical response and the thermoresponsive behavior are efficiently tuned while partially preserving the crystallinity of the system. In particular, mechanical deformation hampers guest release and hence the macroscopic jumping effect, while trifluoroacetic acid release stiffens the crystals. These complex adaptive responses establish a new crystal engineering strategy to gain further control over dynamic organic crystals.

Rapid Consumption of Dihydrogen Injected into a Shallow Aquifer by Ecophysiologically Different Microbes.

The envisaged future dihydrogen (H2) economy requires a H2 gas grid as well as large deep underground stores. However, the consequences of an unintended spread of H2 through leaky pipes, wells, or subterranean gas migrations on groundwater resources and their ecosystems are poorly understood. Therefore, we emulated a short-term leakage incident by injecting gaseous H2 into a shallow aquifer at the TestUM test site and monitored the subsequent biogeochemical processes in the groundwater system. At elevated H2 concentrations, an increase in acetate concentrations and a decrease in microbial α-diversity with a concomitant change in microbial ß-diversity were observed. Additionally, microbial H2 oxidation was indicated by temporally higher abundances of taxa known for aerobic or anaerobic H2 oxidation. After H2 concentrations diminished below the detection limit, α- and ß-diversity approached baseline values. In summary, the emulated H2 leakage resulted in a temporally limited change of the groundwater microbiome and associated geochemical conditions due to the intermediate growth of H2 consumers. The results confirm the general assumption that H2, being an excellent energy and electron source for many microorganisms, is quickly microbiologically consumed in the environment after a leakage.

Bending, Twisting, and Propulsion of Photoreactive Crystals by Controlled Gas Release.

The rapid release of gas by a chemical reaction to generate momentum is one of the most fundamental ways to elicit motion that could be used to sustain and control the motility of objects. We report that hollow crystals of a three-dimensional supramolecular metal complex that releases gas by photolysis can propel themselves or other objects and advance in space when suspended in mother solution. In needle-like regular crystals, the reaction occurs mainly on the surface and results in the formation of cracks that evolve due to internal pressure; the expansion on the cracked surface of the crystal results in bending, twisting, or coiling of the crystal. In hollow crystals, gas accumulates inside their cavities and emanates preferentially from the recess at the crystal terminus, propelling the crystals to undergo directional photomechanical motion through the mother solution. The motility of the object which can be controlled externally to perform work delineates the concept of "crystal microbots", realized by photoreactive organic crystals capable of prolonged directional motion for actuation or delivery. Within the prospects, we envisage the development of a plethora of light-weight, efficient, autonomously operating robots based on organic crystals with high work capacity where motion over large distances can be attained due to the large volume of latent gas generated from a small volume of the crystalline solid.

The application portfolio empowerment method and ELECTRE-I for optimising the control of ammonia release during the aerobic fermentation process.

Aerobic fermentation composting can transform solid organic waste into biological organic fertiliser, while reducing resource wastage and ecological damage. However, in the composting process, a serious loss of nitrogen occurs, primarily in the form of the release of ammonia gas. The release of ammonia gas not only pollutes the environment, but also diminishes the presence of nutrient elements, resulting in compost products that are lower in quality. Given that many factors influence the release of ammonia gas during the aerobic fermentation process, it is difficult to determine optimal process parameters. In an effort to address this issue, we propose herein a combinational weighting method based on the analytic hierarchy process (AHP) and entropy weighting method to determine the weight of each secondary index. We also establish a parametric optimisation model based on the ammonia release conditions of the ELECTRE-I method that provides a theoretical underpinning and a decision basis for optimising the process parameters that mediate the release of ammonia during the aerobic fermentation process. This method can be widely employed to reduce the release of ammonia gas and may be of significance to the future development of bioengineering-based composting technology.

Assessing human vulnerability in industrial chemical accidents: a qualitative and quantitative methodological approach.

Iran as a developing country is experiencing the industrialization process quickly and is thus exposed to different industrial hazards mostly derived from chemicals. In the light of this problem, this study estimated the human vulnerability in chemical accidents using the software simulation of accidental chlorine gas releases. A mixed method (qualitative and quantitative) study carried out in 4 phases during 2015-2017 in Ray County, Tehran Province. It included a systematic literature review, software simulation, Fuzzy Delphi Analytical Hierarchy Process (FDAHP) hierarchy process study, and creating a reliable tool for purpose of this study in at-risk areas. The valuable finding indicated that decreasing the human vulnerability depends on both social and physical characteristics of area and even the social vulnerability indicators have more important role when compared with the physical vulnerability indicators. The statistical analysis revealed that the human vulnerability has the significant relationship with factors such as type of living place (rural or urban) areas, nationality, economic situation of households, the distance between housing and the nearest exit to main road, health centers, and manufacturing or storing chemical plants (P value < 0.01). The result also showed that the area under study is vulnerable from average to very high, both in its physical and social domains, against industrial chemical accidents. Additional comparative studies are needed to develop and generalize the appropriate set of indicators of human vulnerability to human induced disasters in Iran.

Delignification and enhanced gas release from soil containing lignocellulose by treatment with bacterial lignin degraders.

AIMS: The aim of the study was to isolate bacterial lignin-degrading bacteria from municipal solid waste (MSW) soil, and to investigate whether they could be used to delignify lignocellulose-containing soil, and enhance methane release. METHODS AND RESULTS: A set of 20 bacterial lignin degraders, including 11 new isolates from MSW soil, were tested for delignification and phenol release in soil containing 1% pine lignocellulose. A group of seven strains were then tested for enhancement of gas release from soil containing 1% lignocellulose in small-scale column tests. Using an aerobic pretreatment, aerobic strains such as Pseudomonas putida showed enhanced gas release from the treated sample, but four bacterial isolates showed 5-10-fold enhancement in gas release in an in situ experiment under microanaerobic conditions: Agrobacterium sp., Lysinibacillus sphaericus, Comamonas testosteroni and Enterobacter sp. CONCLUSIONS: The results show that facultative anaerobic bacterial lignin degraders found in landfill soil can be used for in situ delignification and enhanced gas release in soil containing lignocellulose. SIGNIFICANCE AND IMPACT OF THE STUDY: The study demonstrates the feasibility of using an in situ bacterial treatment to enhance gas release and resource recovery from landfill soil containing lignocellulosic waste.

A Robust Metal-Organic Framework for Dynamic Light-Induced Swing Adsorption of Carbon Dioxide.

Adsorbents for CO2 capture need to demonstrate efficient release. Light-induced swing adsorption (LISA) is an attractive new method to release captured CO2 that utilizes solar energy rather than electricity. MOFs, which can be tailored for use in LISA owing to their chemical functionality, are often unstable in moist atmospheres, precluding their use. A MOF is used that can release large quantities of CO2 via LISA and is resistant to moisture across a large pH range. PCN-250 undergoes LISA, with UV flux regulating the CO2 desorption capacity. Furthermore, under UV light, the azo residues within PCN-250 have constrained, local, structural flexibility. This is dynamic, rapidly switching back to the native state. Reusability tests demonstrate a 7.3 % and 4.9 % loss in both adsorption and LISA capacity after exposure to water for five cycles. These minimal changes confirm the structural robustness of PCN-250 and its great potential for triggered release applications.

Comparative study on the thermal runaway characteristics of Li(NixCoyMnz)O2 batteries.

Lithium-ion batteries (LIBs) generate substantial gas during the thermal runaway (TR) process, presenting serious risks to electrochemical energy storage systems in case of ignition or explosions. Previous studies were mainly focused on investigating the TR characteristics of Li(NixCoyMnz)O2 batteries with different cathode materials, but they were conducted in isolation. In this study, the thermal runaway characteristics of prismatic cells that use Li(NixCoyMnz)O2 (with x ranging from 0.33 to 0.9) cathode materials in an inert environment, which are commonly used or proposed for energy storage applications, are examined. The findings of this research show that the normalized gas generation rate remains consistent, regardless of the battery capacity or experimental chamber volume, with a value of 0.1 ± 0.03 mol∙Ah⁻1. High-capacity cells have short jetting durations, and a high nickel content leads to increased mass loss rates. The flammability limits of the gases expelled during thermal runaway, represented by the lower flammability limit (LFL), remain stable at 8 ± 1.8 % with minimal variations. However, the upper flammability limit (UFL) varies significantly, ranging from 30 % to 60 %. Increasing the battery capacity or reducing the experimental chamber volume increases the explosion index. The explosive, combustibility, and jetting duration characteristics of the emitted gases from five different battery chemical compositions provide valuable insights for risk assessment in future electrochemical energy storage systems.

Arctic soil CO2 release during freeze-thaw cycles modulated by silicon and calcium.

Arctic soils are the largest pool of soil organic carbon worldwide. Temperatures in the Arctic have risen faster than the global average during the last decades, decreasing annual freezing days and increasing the number of freeze-thaw cycles (temperature oscillations passing through zero degrees) per year as the temperature is expected to fluctuate more around 0 °C. At the same time, proceeding deepening of seasonal thaw may increase silicon (Si) and calcium (Ca) concentrations in the active layer of Arctic soils as the concentrations in the thawing permafrost layer might be higher depending on location. We analyzed the importance of freeze-thaw cycles for Arctic soil CO2 fluxes. Furthermore, we tested how Si (mobilizing organic C) and Ca (immobilizing organic C) interfere with the soil CO2 fluxes in the context of freeze-thaw cycles. Our results show that with each freeze-thaw cycle the CO2 fluxes from the Arctic soils decreased. Our data revealed a considerable CO2 emission below 0 °C. We also show that pronounced differences emerge in Arctic soil CO2 fluxes with Si increasing and Ca decreasing CO2 fluxes. Furthermore, we show that both Si and Ca concentrations in Arctic soils are central controls on Arctic soil CO2 release, with Si increasing Arctic soil CO2 release especially when temperatures are just below 0 °C. Our findings could provide an important constraint on soil CO2 emissions upon soil thaw, as well as on the greenhouse gas budget of high latitudes. Thus we call for work improving understanding of freeze-thaw cycles as well as the effect of Ca and Si on carbon fluxes, as well as for increased consideration of those factors in wide-scale assessments of carbon fluxes in the high latitudes.

Contaminant source identification within a building: Toward design of immune buildings.

The level of protection of a building against the intentional or accidental release of chemical agents is crucial. Both scenarios could endanger life and safety of the buildings occupants. Equipping buildings with appropriate chemical sensors can alert the building occupants about the contaminant release. The readings of these sensors can be employed to trace the location of release, and help to take the appropriate actions to minimize the casualties. However, only a limited number of them can be installed due to their initial and operating cost. Moreover, there is no information about the source strength, release time and possible source location. This paper reports the development of a methodology to identify the source location using sensors reading from limited locations. The methodology uses the artificial neural network (ANN) as a statistical analysis integrated with a multi-zone airborne contaminant transport model, CONTAM. To evaluate the applicability of this method, the contaminant dispersion within a building was modeled and the results were integrated to an ANN for the source identification. The prediction made by the trained ANN was then evaluated by predicting the source of the contaminant in 40 extra cases, which had not been seen by the network during the training session. The model was able to predict the source location in more than 90% of the cases when the building was monitored by three or more sensors. The results show that the method can be used to help building designers decide the optimum configuration of the sensors required for a space based on the accuracy level of the source detection.

Therapeutic gas-releasing nanomedicines with controlled release: Advances and perspectives.

Nanoparticle-based drug delivery has become one of the most popular approaches for maximising drug therapeutic potentials. With the notable improvements, a greater challenge hinges on the formulation of gasotransmitters with unique challenges that are not met in liquid and solid active ingredients. Gas molecules upon release from formulations for therapeutic purposes have not really been discussed extensively. Herein, we take a critical look at four key gasotransmitters, that is, carbon monoxide (CO), nitric oxide (NO), hydrogen sulphide (H2S) and sulphur dioxide (SO2), their possible modification into prodrugs known as gas-releasing molecules (GRMs), and their release from GRMs. Different nanosystems and their mediatory roles for efficient shuttling, targeting and release of these therapeutic gases are also reviewed extensively. This review thoroughly looks at the diverse ways in which these GRM prodrugs in delivery nanosystems are designed to respond to intrinsic and extrinsic stimuli for sustained release. In this review, we seek to provide a succinct summary for the development of therapeutic gases into potent prodrugs that can be adapted in nanomedicine for potential clinical use.

Effect of lipids complexes on controlling ethylene gas release from V-type starch.

In this study, the effects of n-decanoic acid (n-CA) or coconut oil (CCN) on the release of ethylene from V-type starch (VS) were investigated. Results of differential scanning calorimetry showed that adding n-CA or CCN into VS generated a starch-lipid complex. Results of scanning electron microscopy and confocal laser scanning microscopy indicated that VS granules aggregated but oil films appeared on the surface of the VS aggregates when oil was added. The addition of n-CA or CCN effectively delayed the release of ethylene in VS, and the deceleration effect gradually became obvious with the increase in oil addition. These results suggest that the formation of starch-lipid complexes, the aggregation of starch granules, and the presence of oil films play important roles in slowing down the release of ethylene.

Three cases in Japan occurred by natural hazards and lessons for Natech disaster management.

Due to recent climate change, highly-connected society, and the centralization of hazardous materials, Natech is a matter of the growing concern. As Natech disasters occur with low frequency, those in charge of facilities should learn lessons from past cases to prepare for situations in the future in which they may have to respond to a potentially catastrophic event for the first time. This paper describes three Natech cases triggered by the heavy rainfall in Japan in 2018. One resulted in violent explosions, one showed consequences half a year later, and the other managed to avoid a catastrophic situation by preparation based on prior analysis of possible damage. The lessons which can be learnt are as follows: Undertake measures based on the hazardous conditions of materials and possible reactions; Avoid normalcy bias for improved decision-making; Identify slow developing and lagging Natech consequences; Prepare and intensify safeguards to avoid possible damage based on risk analysis; Consider employees' safety in returning to their homes; Collect micro information and aggregate it; Provide current information about the situation to stakeholders; Plan resources required for recovery activities.

Analysis of underwater gas release and dispersion behavior to assess subsea safety risk.

Underwater gas release and dispersion characteristics are important to assess and manage potential risks. This paper presents an experimental and numerical investigation of underwater gas release and dispersion behavior. A small-scale experimental setup is designed and developed for underwater gas release and dispersion study. A series of release scenarios are carried out to study the effect of release size, leak pressure, and leak direction on dispersion behavior. The underwater gas dispersion behavior is analyzed from the risk assessment perspective. The considered parameters included plume offset, plume radius and fountain height for different scenarios. The experimental results are used to test and verify numerical computational fluid dynamics model using Eulerian-Lagrangian approach. The developed numerical model is subsequently used to analyze the gas plume in a full-scale scenario. The developed model would help to support risk assessment and response planning of potential subsea gas release accidents.

A proposal for a test method for assessment of hazard property HP 12 ("Release of an acute toxic gas") in hazardous waste classification - Experience from 49 waste.

A stepwise method for assessment of the HP 12 is proposed and tested with 49 waste samples. The hazard property HP 12 is defined as "Release of an acute toxic gas": waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid. When a waste contains a substance assigned to one of the following supplemental hazards EUH029, EUH031 and EUH032, it shall be classified as hazardous by HP 12 according to test methods or guidelines (EC, 2014a, 2014b). When the substances with the cited hazard statement codes react with water or an acid, they can release HCl, Cl2, HF, HCN, PH3, H2S, SO2 (and two other gases very unlikely to be emitted, hydrazoic acid HN3 and selenium oxide SeO2 - a solid with low vapor pressure). Hence, a method is proposed:For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1L of gas per kg of waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric bombs or glass flasks were done and confirmed the results. Identification of the gases by portable probes showed that most of the tested samples emit mainly CO2. Toxic gases are emitted by four waste: metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator (H2S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in these trials started before the present definition of HP 12. According to the definition of HP 12, only the H2S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed. These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are also classified as hazardous for other properties (HP 7, 10and14 for one of them, and HP 10and14 for the other one respectively). Given these results, it can be assumed that few common household and industrial waste will be classified hazardous only by HP 12.

Nutritional value of forage species from the Central Highlands Region of Mexico at different stages of maturity / Valor nutricional de espécies forrageiras nativas da Região Central Montanhosa do México em diferentes estádios de maturidade

This paper has two objectives, the first is to determine the chemical composition, gas production parameters and the gas release kinetics, at different stages of maturity, of three grasses and a legume commonly found in long established pastures in Mexico central highland plateau. The second is to combine the gas release kinetics analysis and the GP fitted to a mathematical model in order to improve the biological understanding of the fermentation kinetics obtained from the GP technique. Representative samples of Pennisetum clandestinum (kikuyu grass), Sporobolus indicus (mouse tail), Eleocharis dombeyana (reed), Trifolium amabile (Aztec clover) plus a composite sample were collected in the growing season (July, September and November 2003) and analysed using an in vitro gas production (GP) technique. The accumulated GP was fitted to the model described in PALMER et al. (2005). Significant differences (P<0.001) were observed among species and periods for chemical composition, organic matter and neutral detergent fibre digestibility. Significant differences (P<0.05) were observed regarding fermentation parameters and gas release kinetic, with T. amabile and P. clandestinum being the species with the highest fermentability, whereas S. indicus and E. dombeyana were poorly fermented. P. clandestinum and T. amabile showed higher nutritive value than S. indicus and E. dombeyana. Composite samples were influenced by the chemical and fermentation characteristics of all species. It was concluded that the use of gas release kinetics analysis was useful for differentiating the fermentation kinetic of the soluble and insoluble fraction in the grasses and legume. Therefore by performing both approaches, the gas release kinetics analysis and the GP fitted to a mathematical model, gave a better description of the fermentation kinetic of grasses and the legume was achieved when only one approach had been used.

O uso da análise de cinética de produção de gases, em conjunto com a análise de prova de curva e as propriedades químicas da forragem permitem uma melhor descrição das características nutritivas das forragens. Objetivou-se estudar a composição nutritiva e características de fermentação de ruminal de três gramíneas, uma leguminosa e uma mistura composta de pastagens do Planalto Montanhoso Central do México. As amostras representativas de Pennisetum clandestinum (kikuyu grama), Sporobolus indicus (rabo de rato), Eleocharis dombeyana (cana), Trifolium amabile (trevo asteca) mais uma amostra composta foram coletadas durante os meses de Julho, Setembro e Novembro de 2003. Foi utilizada a técnica de produção de gás in vitro (GP). Os perfis de GP foram ajustados ao modelo descrito por PALMER et al. (2005). As diferenças (P<0.001) foram observadas entre espécies e períodos quanto à composição química, matéria orgânica e digestibilidade da fibra em detergente neutro. As diferenças (P<0.05) dos parâmetros de fermentação e cinética de produção de gases mostraram T. amabile e P. clandestinum com fermentação mais intensa, ao passo que S. indicus e E. dombeyana tiveram fermentação limitada. Concluiu-se que a combinação da análise de cinética de produção de gases e o perfil de GP ajustado ao modelo matemático ajudou a descrever as características nutritivas das gramíneas, da leguminosa e da amostra composta de forma mais acurada do que quando um dos métodos foi utilizado de forma isolada.