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The photoelectric effects on the instability of the current-driven dust ion-acoustic (DIA) waves in a collisional and streaming dusty plasmas are theoretically investigated using fluid model with dust charge fluctuation considering dust grains as negatively charged. It is found that the photoelectric effects through dust charge fluctuation give the growth of the DIA waves beside the damping effects of collision and streaming of the plasma species. Growth rate of the DIA waves are numerically investigated using the values of appropriate plasma parameters.

Effective production of natural gas from hydrate-bearing sediments by using various strategies (such as depressurization) is an important way to solve the current global energy crisis. Nevertheless, hydrate dissociation during gas production can weaken sediment strength, influencing reservoir stability and subsequent gas production. Previous studies focused mainly on the analysis of production behavior of natural gas from hydrates, but few on reservoir stability. In this work, evolution of gas production, reservoir characteristics and sediment deformation were analyzed thoroughly with ABAQUS platform. Investigation on gas production revealed that the average production rate was 5.57 × 10 4 m 3 /day, indicating that development strategies mentioned herein can achieve the goal of commercial development of gas hydrates. Although the changes of hydrate saturation and effective stress both affected the characteristics of hydrate reservoir throughout hydrate development operation, hydrate saturation was the main influencing factor. The contour of the distribution nephogram of reservoir characteristics basically coincided with that of the hydrate saturation distribution nephogram. Meanwhile, the yield area around wellbore appearing in the early stage of development operation corresponded to the area prone to sand production. However, the yield area near the seabed appearing in the late stage of development operation corresponded to the area prone to submarine landslide. Finally, investigation on sediment deformation indicated, except for the dissociation area, which experienced significant compaction, the sediments in other areas in the confined space experienced continuous subsidence. This study is expected to lay a theoretical foundation for proposing engineering measures to avoid uncontrollable geological disasters in the process of hydrate development.

Natural gas is a worldwide commodity traded among regions. Regulated or unregulated natural gas markets are in a new process phase leading to a critical change in the market structure and organization while demand grows. Moreover, international trade of high gas volumes and complexity of transportation alternatives create new difficulties in market modeling and price forecasting. Hence, there is a need to define and analyze the future of recently developing gas markets. Turkey has an important geopolitical position with short distances to the regions of the largest natural gas reserves. While largely dependent on the gas import from Russia, Iran and Azerbaijan through pipelines, it is also very close to high demanding countries. That is why Turkey may have the opportunity to play an important role in pricing gas between international market players and becoming a market maker. This paper aims to underline the importance of hub pricing through structuring a virtual gas trade hub in Turkey.

Detection of volatile organic compounds (VOCs) from the breath is becoming a viable route for the early detection of diseases non-invasively. This paper presents a sensor array of 3 component metal oxides that give maximal cross-sensitivity and can successfully use machine learning methods to identify four distinct VOCs in a mixture. The metal oxide sensor array comprises NiO-Au (ohmic), CuO-Au (Schottky), and ZnO–Au (Schottky) sensors made by the DC reactive sputtering method and having a film thickness of 80–100 nm. The NiO and CuO films have ultrafine particle sizes of < 50 nm and rough surface texture, while ZnO films consist of nanoscale platelets. This array was subjected to various VOC concentrations, including ethanol, acetone, toluene, and chloroform, one by one and in a pair/mix of gases. Thus, the response values show severe interference and departure from commonly observed power law behavior. The dataset obtained from individual gases and their mixtures were analyzed using multiple machine learning algorithms, such as Random Forest (RF), K-Nearest Neighbor (KNN), Decision Tree, Linear Regression, Logistic Regression, Naive Bayes, Linear Discriminant Analysis, Artificial Neural Network, and Support Vector Machine. KNN and RF have shown more than 99% accuracy in classifying different varying chemicals in the gas mixtures. In regression analysis, KNN has delivered the best results with an R 2 value of more than 0.99 and LOD of 0.012 ppm, 0.015 ppm, 0.014 ppm, and 0.025 ppm for predicting the concentrations of acetone, toluene, ethanol, and chloroform, respectively, in complex mixtures. Therefore, it is demonstrated that the array utilizing the provided algorithms can classify and predict the concentrations of the four gases simultaneously for disease diagnosis and treatment monitoring. Graphical Abstract

Billingham UK, where Mike Spencer spent his entire industrial career, has long been associated with the use of steam reforming for the production of synthesis gas required for the manufacture of some important chemicals, particularly ammonia and methanol. This paper describes the steam reforming process and presents some of the history of the development of tubular reforming. The catalysts, technology and industrial operation of plants are briefly reviewed. Newer technologies, such as adiabatic reforming, autothermal reforming (ATR) and gas heated reforming (GHR) that aim to increase efficiency of and reduce the environmental impact of conventional steam reforming processes are presented.

A post-rift Aptian magmatism is recorded in a 500-m-thick sequence of basalts interbedded with marls in the Bacalhau oil and gas field in Santos Basin, SE Brazil. This magmatic section is within the so-called pre-salt sequence of Santos Basin that comprises the major oil and gas reserves of Brazil. This is the first publication of systematic petrological and geochronological data for the Aptian magmatism in Santos. Whole-rock Ar–Ar integrated ages obtained for these basalts are 116.93 ± 0.22 Ma, 116.16 ± 0.10 Ma, 115.21 ± 0.13 Ma and 109.95 ± 0.20 Ma and. As such, they are younger than the rift-related Camboriú basalts in Santos as well as the Paraná-Etendeka basalts and related dike swarms. The Santos basalts comprise a low-Ti tholeiitic suite with La/Nb n (2.7–4.2) and La/Yb n (4.2–5.9) ratios typical of continental flood basalt provinces. The basalts vary in MgO content but show no evidence for cogeneticity by differentiation processes. Lithogeochemical data showed that the Aptian basalts in Santos cannot be related with either the low-Ti, Esmeralda and Gramado suites in Paraná-Etendeka or the low-Ti Lumiar, Serrana, and Costa Azul suites in the Serra do Mar Dike Swarm on the basis of lithogeochemical data. No geochemical and isotopic correlation can be done with the Aptian, Alagoas basalts in Campos basin as well. Initial (115 Ma) isotope ratios (Sr: 0.705747–0.706804; εNd: −5.9 to −2.8; 206 Pb/ 204 Pb: 17.61–18.67; 207 Pb/ 204 Pb: 15.47–15.58; 208 Pb/ 204 Pb: 38.17–38.39; εHf: + 0.3 to −8.2) indicate derivation from a EM1 mantle component in the SCLM. Modal batch partial melting modelling showed that melting occurred within the garnet stability zone. We propose a geodynamic model for the Aptian in Santos in which the melting of the SCLM is related with either the presence of the Tristan da Cunha mantle plume in Aptian time below Santos or stretching of different portions of the blob-rich SCLM itself. This stretching is due to the remaining heat advected from Tristan during the voluminous Early Cretaceous magmatism that gave rise to the Paraná-Etendeka CFB.

Anaerobic digestion (AD) from organic waste has gained worldwide attention in reducing greenhouse gas emissions, lowering fossil fuel combustion, and facilitating a sustainable renewable energy supply. Biogas mainly consists of methane (CH 4 ) (50–75%), carbon dioxide (CO 2 ) (25–50%), hydrogen sulphides (H 2 S), hydrogen (H 2 ), ammonia (NH 3 ) (1–2%) and traces of other gases such as oxygen (O 2 ) and nitrogen (N 2 ). Methane can replace fossil fuels in various applications such as heat and power generation and the transportation sector. The degradation of organic waste through an AD process offers many advantages, such as the decrease of pathogens and prevention of odour release. The digestate from anaerobic fermentation is a valuable fertilizer, however, the amount of organic materials currently available for biogas production is still limited. New substrates, as well as more effective conversion technologies, are needed to grow this industry globally. This paper reviewed the latest trends and progress in biogas production technologies including potential feedstock. Recycling of waste has recently become an important topic and has been explored in this paper.

Context In this research, CO 2 and NO 2 adsorption on doped nanographene (NG) sheets with transition metals (Fe, Ni, Zn) and (Mn, Co, Cu), respectively, have been applied for scavenging of these toxic gases as the environmental pollutants. The values of changes of atomic charge density have illustrated a more significant charge transfer for Ni-doped C-NG through CO 2 adsorption and a more remarkable charge transfer for Co-doped C-NG through NO 2 adsorption. The data of NMR spectroscopy has depicted several fluctuations around the graph of Zn-doped on the nanographene surface. The thermodynamic results from IR spectroscopy have indicated that Δ G ads , NO 2 → TM @ C - NG o values are almost similar for doped metal transitions of Mn, Co, and Cu on the C-NG nanosheet, while Δ G ads , CO 2 → TM @ C - NG o has the largest gap of Gibbs free energy adsorption with dipole moment. Methods The Langmuir adsorption model with a three-layered ONIOM using CAM-B3LYP functional accompanying LANL2DZ, EPR-III and 6-31 + G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO 2 → (Fe, Ni, Zn) and NO 2 → (Mn, Co, Cu) doped on the C-NG has been accomplished. Then, NMR and IR spectroscopy, nuclear quadrupole resonance, and natural bond orbital analysis have been accomplished for evaluating chemical shielding tensors, thermodynamic properties, electric potential, and occupancy fluctuation through bond orbitals, respectively. In addition, frontier orbitals of LUMO, HOMO, and also a series of chemical reactivity parameters have been calculated. Finally, time-dependent-DFT method due to UV-VIS spectrums has been accomplished to discern the low-lying excited states of CO 2 and NO 2 adsorption on the (Fe, Ni, Zn) and (Mn, Co, Cu), respectively, doped C-NG sheet.

In order to elucidate the differences on aroma compounds in Chinese liquors with different aroma styles and the reasons, aroma compounds of Xijiu in soy sauce aroma and strong aroma type were investigated in the research. By gas chromatography–olfactometry (GC–O), aroma compounds in Chinese liquor were chosen for quantitative and odor activity value (OAV) analysis. Ethyl hexanoate, butanoic acid, 3-methylbutanoic acid, hexanoic acid and dimethyl trisulfide were considered to be the most powerful odorants in both liquor samples (aroma intensity ≥3.5) by GC–O. As important aroma compounds (OAV ≥10) in the liquors, ethyl propanoate, ethyl 2-methylpropanoate and 1-propanol were considered with much higher OAVs in soy sauce aroma type liquor, while OAVs of ethyl pentanoate, ethyl hexanoate, ethyl heptanoate, ethyl octanoate, ethyl lactate, hexyl acetate, butyl hexanoate, hexyl hexanoate and hexanoic acid were far lower in strong aroma type liquor. The OAV of ethyl hexanoate in strong aroma type liquor exceeded 50,000, which explained the reason why strong aroma liquor was considered with prominent fruity aroma. The odor differences between the liquors were mainly caused by the manufacturing practices.

Power transformers are a key component of electrical networks, and they are both expensive and difficult to upgrade in a live network. Many utilities monitor the condition of the components that make up a power transformer and use this information to minimize the outage and extend the service life. Routine and diagnostic tests are currently used for condition monitoring and appraising the ageing and defects of the core, windings, bushings and tap changers of power transformers. To accurately assess the remaining life and failure probability, methods have been developed to correlate results from different routine and diagnostic tests. This paper reviews established tests such as dissolved gas analysis, oil characteristic tests, dielectric response, frequency response analysis, partial discharge, infrared thermograph test, turns ratio, power factor, transformer contact resistance, and insulation resistance measurements. It also considers the methods widely used for health index, lifetime estimation, and probability of failure. The authors also highlight the strengths and limitations of currently available methods. This paper summarizes a wide range of techniques drawn from industry and academic sources and contrasts them in a unified frame work.