In underground coal gasification, as a choke regulating the formation gas lift pressure, the throttling tool can effectively reduce the production cost, the number of ground heating and insertion equipment, and gas consumption. Because in this process, the coal is transformed into composite synthetic gas through a series of technical treatments, the throttling tool is in a working environment with high temperature and pressure. In the process of transportation of combined synthetic gas, the pulverized coal parts produced by incomplete coal combination move with the gas in the throttling tool. The high temperature and high-pressure gas carrying large-diameter pressed coal parts will cause serial erosion and wear to the throttling device, resulting in failure and well-controlled safety risks. Therefore, according to the Joule−Thomson effect, this paper independently designs downhole throttling tools with single- and double-hole structures. According to actual field conditions, the erosio... [more]

Self-assembly of nanoscale objects is of essential importance in materials science, condensed matter physics, and biophysics. Curvature modifies the principles and sequence of self-assembly in Euclidean space, resulting in unique and more complex structures. Understanding self-assembly behavior in curved space is not only instrumental for designing structural building blocks and assembly processes from a bottom-up perspective but is also critically important for delineating various biological systems. In this review, we summarize efforts made to unveil the physical nature of self-assembly in curved space through experiments and simulations. First, we outline the differences in the physical nature of self-assembly between curved space and Euclidean space by presenting relevant results of experiments and simulations. Second, we explore the principles of self-assembly in curved space at multiple scales and interactions, elucidating important factors that govern the self-assembly process f... [more]

Effective fluid-loss control in oil wells is a critical concern for the oil industry, particularly given the substantial reserves situated in carbonate reservoirs globally. The prevalence of such reservoirs is expected to rise with the slow depletion of hydrocarbons, intensifying the need to address challenges related to deteriorating reservoir properties post well-killing operations. This deterioration results in significant annual losses in hydrocarbon production at major oil enterprises, impacting key performance indicators. To tackle this issue, this study focuses on enhancing well-killing technology efficiency in carbonate reservoirs with abnormally low formation pressures. To address this issue, the authors propose the development of new blocking compositions that prevent the fluid loss of treatment fluids by the productive reservoir. The research tasks include a comprehensive analysis of global experience in well-killing technology; the development of blocking compositions; an i... [more]

Traditional research on apparent permeability in shale reservoirs has mainly focussed on effects such as poromechanics and porosity-assisted adsorption layers. However, for a more realistic representation of field conditions, a comprehensive multi-scale and multi-flowing mechanism model, considering the fracturing process, has not been thoroughly explored. To address this research gap, this study introduces an innovative workflow for dynamic permeability assessment. Initially, an accurate description of the pore size distribution (PSD) within three major mineral types in shale is developed using focussed ion beam-scanning electron microscopy (FIB-SEM) and nuclear magnetic resonance (NMR) data. Subsequently, an apparent permeability model is established by combining the PSD data, leading to the derivation of dynamic permeability. Finally, the PSD-related dynamic permeability model is refined by incorporating the effects of imbibition resulting from the fracturing process preceding shale... [more]

Egypt faces significant challenges in managing its sewage sludge generated in large quantities from wastewater treatment plants. This study investigates the feasibility of utilizing sewage sludge as a renewable resource for hydrogen production through anaerobic digestion at the 100 L bioreactor level. Hydrogen is considered a promising alternative energy source due to its high energy content and environmental benefits. To optimize the microbial degradation process and maximize hydrogen production from sewage sludge, a specialized pretreatment is necessary. Various pretreatment methods have been applied to the sewage sludge, individually and in combination, to study the bio-hydrogen production from sewage sludge. The four methods of treatment were studied in batch assays as a pilot scale. Thermal pretreatment of sewage sludge significantly increases bio-hydrogen production yield compared to other sewage sludge pretreatment methods, producing the highest H2 yield (6.48 LH2/g VS). In gene... [more]

Shale oil resources, noted for their broad distribution and significant reserves, are increasingly recognized as vital supplements to traditional oil resources. In response to the high fracturing costs and swift decline in productivity associated with shale oil horizontal wells, this research introduces a novel approach utilizing CO2 for enhanced shale oil recovery in radial boreholes. A compositional numerical simulation method is built accounted for component diffusion, adsorption, and non-Darcy flow, to explore the viability of this technique. The study examines how different factors—such as initial reservoir pressure, permeability, numbers of radial boreholes, and their branching patterns—influence oil production and CO2 storage. Our principal conclusions indicate that with a constant CO2 injection rate, lower initial reservoir pressures predominantly lead to immiscible oil displacement, hastening the occurrence of CO2 gas channeling. Therefore, maintaining higher initial or inject... [more]

Impurities in the CO2 stream should be removed to prevent eventual phase changes in CO2 transportation because a two-phase flow caused by the phase change in the pipeline necessitates additional overpressure and can induce equipment damage. In this study, CO2 compression and liquefaction (CCL) processes with a distillation column were used to remove non-condensable impurities and were compared with those with a flash. Three different feeds with a flow rate of 50.1 t/h (400,500 t/y) were supplied to the CCL processes and compressed to 65 bar to gauge pressure (barg) and 20 °C. Although the CO2 mixtures obtained through dehydration and flashing met the purity requirements for transportation and storage recommended in literature, the flash-separated CO2 product at 65 barg demonstrated the coexistence of gas and liquid phases, which restricted the temperature window for liquid CO2 transportation. When the distillation column was used instead of the flash, the operating temperature window a... [more]

The pre-tightening force loss (PTFL) of bolts is an important but underestimated cause of roadway instability. In mine anchorage systems, the actual pre-tightening force of bolts is only 50% to 80% of the design value. Through a case study at Xiahuo Coal Mine, it was found that the essential causes of PTFL are the increasing friction coefficient between supporting units controlled by factors such as pre-tightening torque levels, pre-tightening cycles, and surrounding rock roughness. This study investigates the behavioral characteristics of PTFL and its influence on surrounding rock failure in roadways. This research reveals a linear correlation between pre-tightening force and torque, with an average torque conversion coefficient of approximately 0.19. However, the PTFL increases with higher levels of pre-tightening torque, increasing pre-tightening cycles, and rougher surrounding rock conditions. For every 30 N·m increase in pre-tightening torque, the PTFL increases by approximately 1... [more]

This work investigated hydrogen production from biomass feedstocks (i.e., glucose, starch, lignin and cellulose) using a 100 mL h-type proton exchange membrane electrolysis cell. Biomass electrolysis is a promising process for hydrogen production, although low in technology readiness level, but with a series of recognised advantages: (i) lower-temperature conditions (compared to thermochemical processes), (ii) minimal energy consumption and low-cost post-production, (iii) potential to synthesise high-volume H2 and (iv) smaller carbon footprint compared to thermochemical processes. A Lewis acid (FeCl3) was employed as a charge carrier and redox medium to aid in the depolymerisation/oxidation of biomass components. A comprehensive analysis was conducted, measuring the H2 and CO2 emission volume and performing electrochemical analysis (i.e., linear sweep voltammetry and chronoamperometry) to better understand the process. For the first time, the influence of temperature on current density... [more]

This paper presents an approach for optimizing the oil recovery factor by determining initial oil production rates. The proposed method utilizes the Q-learning method and the reservoir simulator (Eclipse 100) to achieve the desired objective. The system identifies the most efficient initial oil production rates by conducting a sufficient number of iterations for various initial oil production rates. To validate the effectiveness of the proposed approach, a case study is conducted using a numerical reservoir model (SPE9) with simplified configurations of two producer wells and one injection well. The simulation results highlight the capabilities of the Q-learning method in assisting reservoir engineers by enhancing the recommended initial rates.

The group of nontuberculous mycobacteria (NTM) includes about 200 mycobacteria that are widespread in the natural environment as free-living saprophytic bacteria, commensals or symbionts. NTM, also referred to as atypical mycobacteria, are mostly apathogenic; nowadays, they are increasingly important environmental opportunistic pathogens. This study continues the work of previous studies which investigated the individual and synergistic effect of different essential oils (EOs) on NTM. The aim was to investigate the effect of the interaction of the common juniper (Juniperus communis) EO and the antimicrobials, amikacin, clarithromycin and rifampicin, against Mycobacterium avium and M. intracellulare using the checkerboard synergy method in an enriched Middlebrook 7H9 broth. Morphological changes of treated NTM cells were observed with a transmission electron microscope. The most synergistic combinations were found at subinhibitory concentrations of the common juniper EO and rifampicin a... [more]

At the level of skin wounds, an electrical potential difference develops between the edges of the wound and the center of the wound, which favors the migration of cells in the process of their healing. Cells migrate in an electric field because they have a certain electrical membrane potential. This potential is due to differences in the transmembrane electrochemical gradient. The transmembrane electrochemical gradient is due to the migration of sodium, potassium, and calcium ions into the corresponding ion channels. If this is the case, the modification of the functionality of these ion channels should influence the membrane potential and, as a consequence, the wound healing process. In this experiment, we set out to investigate whether the chemical manipulation of ion channels by amiodarone influences the wound healing process. Amiodarone blocks several types of ion channels, but at different concentrations: at low concentrations, it blocks only potassium channels; at medium concentr... [more]

This review focuses on the energy structure of iron and steel production and a feasible development path for carbon reduction. The process path and feasible development direction of carbon emission reduction in the iron and steel industry have been analyzed from the perspective of the carbon−electricity−hydrogen ternary relationship. Frontier technologies such as “hydrogen replacing carbon” are being developed worldwide. Combining the high efficiency of microwave electric-thermal conversion with the high efficiency and pollution-free advantages of hydrogen-reducing agents may drive future developments. In this review, a process path for “microwave + hydrogen” synergistic metallurgy is proposed. The reduction of magnetite powder by H2 (CO) in a microwave field versus in a conventional field is compared. The driving effect of the microwave field is found to be significant, and the synergistic reduction effect of microwaves with H2 is far greater than that of CO.

The aim of this work is to present in a systematic way a novel general methodology to develop the design equations (heat and mass balances) for networks of ideal reactors, that is, Plug-Flow Reactors (PFRs) and Continuous Stirred Tank Reactors (CSTRs). In particular, after introducing the general definition of conversion to be used for reactor networks, several case studies of interest in chemical engineering are presented as topic-examples of application: (i) adiabatic-stage reactors with recycle, (ii) adiabatic-stage reactors with split, (iii) adiabatic-stage reactors intercooled by reactants and (iv) adiabatic-stage reactors with interstage distributed feed. More generally, the presented methodology can also be applied to develop the design equations for complex networks of interconnected reactors, not restricted to those considered in the present work. The motivation behind the present study lies in the fact that, to the best of our knowledge, a systematic development of the design... [more]

A floatation nozzle can effectively transfer heat and dry without touching the substrate, and serves as a vital component for heat transfer to the substrate. Enhancing the heat transfer performance, and reducing its heat transfer unevenness to the substrate play an important role in improving product quality and reducing thermal stress. In this work, the effects of key structural parameters of the floatation nozzle on the heat transfer mechanism are systematically investigated by means of a numerical simulation of computational fluid dynamics. The findings demonstrate that the secondary vortex structure induced by the floatation nozzle with effusion holes increases heat transfer performance by 254.3% compared with the nozzle without effusion holes. The turbulent kinetic energy and temperature distribution between the jet and the target surface are affected by the jet angle and slit width respectively, which change the heat transfer performance of the float nozzle in different degrees.... [more]

This study aims to elucidate the mechanism by which the ultrasonic loading of metal affects the extraction of small molecular phase substances (low molecular compounds) in tar-rich coal. Tar-rich coal samples were collected from the Huangling mining area in the southeastern Ordos Basin, China. The coal, the leaching solution of the coal, the extraction products, and the extraction residual coal samples with different metal ions loaded by ultrasound were analyzed using field emission scanning electron microscopy, pH detection, gas chromatography−mass spectrometry, a Fourier transform infrared spectrometer, and an X-ray diffractometer. The obtained results indicated that the ultrasonic loading of coal samples with different metal ions (Mn2+, Co2+, Cu2+, Fe2+, and Ni2+) promoted the extraction of small molecular phase substances in coal and increased the proportion of extracted aliphatic hydrocarbons, alkylbenzene, naphthalene, phenanthrene, and other compounds. The extraction rate of Mn2... [more]

This paper investigates the decentralized fuzzy control problems for nonlinear-state-unmeasured interconnected descriptor systems (IDSs) that utilize the observer-based-feedback approach and the proportional−derivative feedback control (PDFC) method. First of all, the IDS is represented as interconnected Takagi−Sugeno (T−S) fuzzy subsystems. These subsystems can effectively capture the dynamic behavior of the system through fuzzy rules. For the stability analysis of the system, this paper uses the free-weighing Lyapunov function (FWLF), which allows the designer to set the weight matrix, to achieve the desired control performance and design the controller more easily. Furthermore, the control problem can be transformed into a set of linear matrix inequalities (LMIs) through the Schur complement, which can be solved using convex optimization methods. Simulation results confirm the effectiveness of the proposed method in achieving the desired control objectives and ensuring system stabil... [more]

This paper proposes a high-efficiency and compact fuel cell−battery hybrid power system without DC/DC converters. Generally, fuel cells supply power to charge lithium batteries or loads using DC/DC converters. The disadvantages of a DC/DC converter are its complex design, poor efficiency, and large volume. Therefore, improvements in the volume, weight, and efficiency are the main objectives of the proposed topology, which is suitable for stable operation in power equipment. This paper proposes a novel topology without DC/DC converters for a fuel cell−battery hybrid forklift system and analyzes, discusses, and verifies it with experimental measurements. Additionally, the proposed topology uses an average charging method to charge the Li-ion battery. The dynamic response of fuel cells is slower than that of Li-ion batteries. By properly configuring the voltages of a fuel cell and a lithium battery, we propose a hybrid system that can maintain a stable output and high efficiency in differ... [more]

Titanium carbide has attracted widespread attention due to its excellent properties. This study investigates the process of carbon thermally reducing TiO2 to prepare TiC through a combination of thermodynamic analysis and experiments. The effects of temperature, TiO2/C molar ratio, and time on the phase transformation and morphology evolution of the products are investigated. The synthesis of titanium carbide involves the main reduction path of TiO2−Magnéli−Ti3O5−Ti2O3−TiCxO1−x. With the increase in reaction temperature and TiC content, the microstructure transitions from a smooth disc-like structure to a loose and porous layered structure, while the particle size decreases significantly. The carburisation rate of the reduced product is more affected by temperature, according to chemical analysis. The carburisation rate increased from 18.37% to 36.09% for 2 h−10 h of holding time at 1400 °C, and from 51.43% to 77.57% for 2 h−10 h of holding time at 1500 °C. The quantification of the ca... [more]

Electrostatic precipitators (ESP) are especially known for the efficient separation of micron and submicron particles from aerosols. Wet electrostatic precipitators are particularly suitable for highly resistive materials. Using these, particles can be directly transferred into a liquid for further processing or safer handling, which is advantageous for either hazardous or valuable materials. In this work, a wet ESP, which enables the separation of highly resistive particles into a heated liquid, was designed and investigated. To do this, spray-dried drug particles were embedded in a molten sugar alcohol to enhance the drug dissolution rate. After cooling, the solidified product showed advantageous properties such as a high drug dissolution rate and easy handling for further processing. For the design of the wet ESP, different discharge electrode configurations were tested. A wall film served as the collection electrode, which was generated by a specially designed distributer die. A la... [more]

The research program “Engineered Artificial Minerals (EnAM)” addresses the challenge of recycling valuable elements from battery waste streams. These elements, such as lithium (Li), often migrate in the slag phase, in some cases as crystals. EnAM crystals represent concentrated reservoirs of these elements, which can only be effectively recycled if they are extracted from the slag matrix and then separated. Selective wet agglomeration is a separation process based on a three-phase system and is often used in coal and ore processing. The produced agglomerates in this process can be easily separated from the remaining suspension. The precise quantification of the wetting properties and adhesion strength between suspended particles and binding liquid droplets is a scientific challenge. An accurate technique suitable for adhesion force measurements in three-phase systems with micrometer-scale particles is Fluidic Force Microscopy (FluidFM®). An experimental setup with optical control is be... [more]

In this study, the effects of ultrasonic power, drying temperature, and slice thickness on the drying rate, chromatism, water migration law, gingerol content, flavor, and antioxidant activity of ginger were investigated by using a direct-contact ultrasound and far infrared combined drying technology. The results showed that compared with single far infrared drying, direct-contact ultrasound and far infrared combined drying accelerated the free water migration rate of ginger (7.1~38.1%), shortened the drying time (from 280 min to 160 min), reduced the loss of volatile components in ginger, and significantly increased the antioxidant activity of ginger (p < 0.05). Furthermore, after ultrasound intervention, the gingerol content decreased in slices of 4 mm thickness (0.1226 ± 0.0189 mg/g to 0.1177 ± 0.0837 mg/g) but increased in slices of 6 mm thickness (0.1104 ± 0.0162 mg/g to 0.1268 ± 0.0112 mg/g). This drying technology has a certain reference significance for the drying process of... [more]

A pumping-while-tripping method is proposed to mitigate pressure swabs during tripping out in wells with a narrow mud density window and extended reach. In the proposed tripping-out process, the fluid circulation is started by using a special pump from a customized circulation line before tripping is initiated. During the tripping out, drilling fluid is circulated in the wellbore simultaneously while the drilling string is moving. A model to simulate the dynamic pressure changes in this process is developed based on the Navier−Stokes (N-S) equations and a damped free vibration system. The model was initially developed for Herschel−Bulkley (H-B) fluid; however, it can be applied to other fluid models by eliminating the non-existing terms. An analysis was conducted to investigate the effect of tripping velocity and circulation pumping rate on the pressure changes. The results show that pumping-while-tripping is effective in mitigating the pressure swab during tripping out, which is espec... [more]

Organobentonites have been applied for the removal of two common non-steroidal anti-inflammatory drugs, ibuprofen (IBU) and diclofenac sodium (DS), from aqueous solutions. Two surfactants, one with and the other without benzyl group (octadecyldimethylbenzylammonium chloride, ODMBA, and hexadecyltrimethylammonium bromide, HDTMA), in amounts equivalent to 50, 75, and 100% of the cation exchange capacity of bentonite were used for the preparation of organobentonites. Successful modification of bentonite was confirmed by several methods: X-ray powder diffraction (XRPD), point of the zero charge (pHPZC), determination of exchanged inorganic cations in bentonite, determination of textural properties, and scanning electron microscopy (SEM). Kinetic and thermodynamic data on the adsorption of IBU and DS showed that drug adsorption was controlled by the type and the amount of surfactant incorporated into the bentonite and by their arrangement in the interlayer space and at the surface of organo... [more]

Well deviation is a prevalent problem in deep oil and gas exploration, leading to a significant increase in drilling costs. The conventional bottom-hole assembly (BHA) anti-deviation design method does not consider the impact of the BHA structure on lateral vibration. This paper proposes an integrated BHA design method that takes into account both anti-deviation and vibration reduction. This method evaluates the BHA’s anti-deviation ability using the drilling trend angle. A negative value of the drilling trend angle indicates that the BHA can correct well deviation. A finite element linearized dynamics method is used to evaluate the lateral vibration intensity of the BHA. This method involves calculating the bending displacement caused by mass imbalance and then determining the magnitude of the bending strain energy based on this displacement. The structural factors affecting the anti-deviation ability and potential lateral vibration intensity of pendulum BHAs and bent-housing mud moto... [more]