Low Operating Pressure Research Articles

Computational and Experimental Study on Pressure Drop in a Fluidised Bed with Different Air Distributor Designs

Fluidised bed combustion (FBC) has been recognised as a suitable technology for converting a wide variety of fuels into energy. In a fluidised bed, the air is passed through a bed of granular solids resting on a distributor plate. Distributor plate plays an essential role as it determines the gas-solid movement and mixing pattern in a fluidised bed. It is believed that the effect of distributor configurations such as variation of free area ratio and air inclination angle through the distributor will affect the operational pressure drop of the fluidised bed. This paper presents an investigation on pressure drop in fluidised bed without the presence of inert materials using different air distributor designs; conventional perforated plate, multi-nozzles, and two newly proposed slotted distributors (45° and 90° inclined slotted distributors). A 3-dimensional Computational Fluid Dynamics (CFD) model is developed and compared with the experimental results. The flow model is based on the incompressible isothermal RNG k-epsilon turbulent model. In the present study, systematic grid-refinement is conducted to make sure that the simulation results are independent of the computational grid size. The non-dimensional wall distance, is examined as a key factor to verify the grid independence by comparing results obtained at different grid resolutions. The multi-nozzles distributor yields higher distributor pressure drop with the averaged maximum value of 749 Pa followed by perforated, 45° and 90° inclined distributors where the maximum pressure drop recorded to be about one-fourth of the value of the multi-nozzles pressure drop. The maximum pressure drop was associated with the higher kinetic head of the inlet air due to the restricted and minimum number of distributor openings and low free area ratio. The results suggested that low-pressure drop operation in a fluidised bed can be achieved with the increase of open area ratio of the distributor.

Domestic Organic Rankine Cycle-Based Cogeneration Systems as a Way to Reduce Dust Emissions in Municipal Heating

Environmental issues are nowadays of great importance. In particular air and water quality should be kept at as high levels as possible. Energy conversion systems and devices which are applied for converting the chemical energy contained in different fuels into heat, electricity and cold in the industry and housing are sources of different gases and solid particle emissions. Medical data show PM2.5 dust in particular is highly dangerous for human health. Therefore, limiting the number of low-quality fuel combustion processes is a key issue of modern energy policy. Statistical data show that domestic heating systems account for a large share of the total emissions of PM2.5 and PM10 dust. For example in Poland in 2017, the share of households in the total annual emissions of PM2.5 dust was equal to ca. 35.8%, while the share of PM2.5 emission in industry (i.e., power generating plants, industrial power plants and technologies) was equal to only 23.6%. A possible way of solving this problem is by the successful replacement of old domestic furnaces by combined heat and power (CHP) or multigeneration boilers which can be used for heating the rooms and sanitary water and generating electricity and cold. Such systems can possibly contribute in the future to significant reductions of dust emissions and air pollution in urban and rural areas by limiting the number of low-quality fuel combustion processes. This article presents design considerations and experimental results related to a domestic micro-CHP unit which is based on organic Rankine cycle (ORC) technology. The main aim of the design works and experiments was therefore the analysis of the possibility of integrating the ORC system with a standard domestic central heating gas-fired boiler. The specially designed micro-ORC system was implemented in the laboratory and experiments were performed using this test stand. The main design aims of the test-stand were: low operating pressure, small working fluid flow, low price and compact dimensions. To meet these aims, volumetric machines were chosen as the expander and working fluid pump. The experimental results were positive and show that it is possible to integrate an ORC system with a standard domestic central heating gas boiler. For different heat source temperatures, the obtained expander power ranged from 109 W to 241 W and the thermodynamic cycle efficiency ranged from 4.3% to 8.8%. These positive research results were achieved partly thanks to the positive features of the different system subassemblies.

A cellulose-based nanofiltration membrane with a stable three-layer structure for the treatment of drinking water

Nanofiltration membrane (NFM) is an effective and advanced semi-permeable membrane (pore size: 1 ~ 2 nm) for deep purification of drinking water due to their low operating pressure and high divalent salt ion rejection. In this work, a stable cellulose-based polyamide nanofiltration membrane (NF-PDA-RCM) with a unique three-layered structure was prepared for advanced treatment of drinking water, via the method of chemical bond connection followed by the interfacial polymerization strategy. The regenerated cellulose membrane (RCM), as the supporting layer of NFM, prepared by phase inversion method has good physical compatibility and abundant porous channels. Further, the flux of NFM can be controlled by adjusting the pore size of the RCM. Through Michael addition reaction, the supporting layer and the active layer of NF-PDA-RCM are connected by the covalent bonds, resulting in a great improvement in the stability of NF-PDA-RCM. The resultant NF-PDA-RCM has increased rejection rate of MgSO4 (enhanced about 9.3%) and water-flux (enhanced about 78.5%) compared with that of no polydopamine (PDA) modified NFM. The RCM are completely biodegradable, allowing the NF-PDA-RCM to be a promising candidate for treating drinking water.

Feasibility of brackish water and landfill leachate treatment by GO/MoS2-PVA composite membranes

Two-dimensional (2D) based layered materials with tunable chemical functionalities and surface charge properties have emerged for on-demand applications including membrane technology. However, the process control, time and energy-efficient production of non-swelling graphene oxide (GO) with retaining physicochemical properties are still challenging. In this work, we have fabricated highly ordered GO membrane on cellulose acetate supporting membrane filters of 1.2 μm pore size using molybdenum disulphide (MoS2) as a nano-spacer and polyvinyl alcohol (PVA) as an adhesive for the first time with limited swelling. The fabricated membranes were used for NaCl rejection and removal of toxic heavy metal ions, and the radioactive element from landfill leachate water. The introduction of hydrophilic PVA, thickness control using a various amount of nanospacer and graphene oxide played a vital role in the transport mechanism, permeability, and selectivity index. The composition of PVA and MoS2 in the coating solution was optimized to tune the d-spacing of graphene oxide layers. The newly developed composite membranes have 89% rejection rate to NaCl and 3.96 L/m2h water flux at low operating pressures of 5 bar. Also, the prepared membranes have a high rejection of multivalent metal ions in landfill leachate. 86.5% to 99.8% rejection rate of multivalent metal ions in landfill leachate was observed for the M3 (GO (10): MoS2 (10): PVA (0.5)) membrane. The excellent rejection performance is ascribed to the combined impact of size exclusion, ion adsorption, electrostatic interaction and Gibbs-Donnan exclusion mechanism. The excellent stability and high rejection rate even after 216 h of operation make the fabricated membranes promising for use in practical water separation applications.

A novel water-stable two-dimensional zeolitic imidazolate frameworks thin-film composite membrane for enhancements in water permeability and nanofiltration performance

Polymer membranes for water treatment are constrained by the permeability-separation trade-off. Herein, two-dimensional (2D) zeolitic imidazolate frameworks (ZIFs) made of benzimidazole interconnected with Zn ions are used to create 2D Zn2(Bim)4 molecular sieve nanosheets, which is explored as an asymmetric, thin-film composite (TFC) nanofiltration (NF) membrane for removing organic dyes and salts from water with a high water permeability under a low operating pressure (1 bar). The 2D Zn2(Bim)4 TFC NF membrane is synthesized via ionic bonds between polycations and the peripheral hydroxy groups of 2D Zn2(Bim)4 nanosheets, regulating the assembly of 2D Zn2(Bim)4 to create a novel crack-free functional layer on top of a polyvinylidene fluoride (PVDF) ultrafiltration membrane. FESEM and XPS confirmed the presence of a polycations-regulated ultrathin functional layer with a thickness of ∼37 nm on the PVDF support. Benefiting from its structural feature, our 2D Zn2(Bim)4 TFC NF membrane could achieve an ultra-high flux of ∼290 L/(m2·h·bar) (5–10-fold higher than that of graphene-based membranes), good anti-fouling properties and high rejection rates (above 98%) for organic dyes. Moreover, the desalinization rate is 50–75%. That is, our membrane is endowed with NF capability, and its intrinsic ultrafiltration features (high water permeance, ultrafast, and energy-saving) are also well maintained.

Heat Exchanger Sizing for Organic Rankine Cycle

Approximately 45% of power generated by conventional power systems is wasted due to power conversion process limitations. Waste heat recovery can be achieved in an Organic Rankine Cycle (ORC) by converting low temperature waste heat into useful energy, at relatively low-pressure operating conditions. The ORC system considered in this study utilises R-1234yf as the working fluid; the work output and thermal efficiency were evaluated for several operational pressures. Plate and shell and tube heat exchangers were analysed for the three sections: preheater, evaporator and superheater for the hot side; and precooler and condenser for the cold side. Each heat exchanger section was sized using the appropriate correlation equations for single-phase and two-phase fluid models. The overall heat exchanger size was evaluated for optimal operational conditions. It was found that the plate heat exchanger out-performed the shell and tube in regard to the overall heat transfer coefficient and area.

Facile hydrophilic modification of PVDF membrane with Ag/EGCG decorated micro/nanostructural surface for efficient oil-in-water emulsion separation

Wettability of porous materials is crucial for the separation of emulsified oil/water mixtures. Herein, high hydrophobicity of polyvinylidene fluoride (PVDF) membrane has been facilely transformed to high hydrophilicity and underwater superoleophobicity via single-step coating of plant-derived epigallocatechin gallate (EGCG) and silver ion (Ag+) in aqueous solution. EGCG can chelate with Ag+ and in-situ reduced it into Ag nanoparticle, meanwhile Ag/EGCG composite was adhered on membrane surface due to the high surface binding affinity of EGCG. The hydrophilic EGCG and formed micro/nanostructure together improved membrane hydrophilicity and oleophobicity. The optimally Ag/EGCG modified PVDF membrane possesses high permeate flux (e.g. 735 L/(m2h) for diesel-in-water emulsion, while it is zero for pristine PVDF membrane) under a low operation pressure of 0.5 bar and high oil rejections in the treatment of surfactant-stabilized oil-in-water emulsions consisting of micro/nano scale droplets. In addition, the membrane exhibits excellent antifouling property with a flux recovery ratio of 98.1% and satisfactory reusability in a 5-cycle test. Moreover, the membrane possessed desired stability during long-term rinsing test and Ag leaching test. This work would offer new insights into surface hydrophilic manipulation of porous membrane towards practical oil emulsion purification.

Prediction of Salmonella inactivation in sliced tomato subject to high pressure processing and trans-cinnamaldehyde treatment using selective and non-selective growth media for survival evaluations

High pressure processing (HPP) is an effective non-thermal food operation means to reduce foodborne illness risks. Trans-cinnamaldehyde (TC) is a GRAS compound widely used in food applications for flavoring and recently found the potential to enhance microbial inactivation with HPP. For the first time, this study investigated combination effects of relatively low hydrostatic pressure level (i.e. 150, 200 and 250 MPa), operation time (i.e. 4, 8 and 12 min) and TC concentration (i.e. 200, 400 and 600 ppm) on Salmonella inactivation in sliced tomato by using both selective (i.e. XLT4 agar plates) and non-selective (i.e. Aerobic Petrifilms™) growth media for microbial survival evaluations. Linear and dimensionless non-linear regression models were developed, evaluated and validated for providing comparative information for descriptions and predictions of the inactivation effects. The results showed that a strong synergistic inactivation effect between hydrostatic pressure and TC was observed, which could explain for the great inactivation effects of the combination treatments (maximum reduction > 6 log CFU/g). The inactivation of Salmonella in XLT4 agar plate counts was significantly larger (up to 1.96 log CFU/g) than in Aerobic Petrifilm™ counts (p < 0.05), suggesting using non-selective growth media could be a more conservative choice than selective growth media, ensuring a higher microbial safety level. According to the novel 4-dimensional response surface plots of developed models, hydrostatic pressure level played the most important role in the inactivation. This study provides valuable reference information to the current HPP manufacturers dealing with tomato products.

COVID-19 and Laparoscopic Surgery: Scoping Review of Current Literature and Local Expertise.

BackgroundThe current coronavirus disease (COVID-19) pandemic is holding the world in its grip. Epidemiologists have shown that the mortality risks are higher when the health care system is subjected to pressure from COVID-19. It is therefore of great importance to maintain the health of health care providers and prevent contamination. An important group who will be required to treat patients with COVID-19 are health care providers during semiacute surgery. There are concerns that laparoscopic surgery increases the risk of contamination more than open surgery; therefore, balancing the safety of health care providers with the benefit of laparoscopic surgery for the patient is vital.ObjectiveWe aimed to provide an overview of potential contamination routes and possible risks for health care providers; we also aimed to propose research questions based on current literature and expert opinions about performing laparoscopic surgery on patients with COVID-19.MethodsWe performed a scoping review, adding five additional questions concerning possible contaminating routes. A systematic search was performed on the PubMed, CINAHL, and Embase databases, adding results from gray literature as well. The search not only included COVID-19 but was extended to virus contamination in general. We excluded society and professional association statements about COVID-19 if they did not add new insights to the available literature.ResultsThe initial search provided 2007 records, after which 267 full-text papers were considered. Finally, we used 84 papers, of which 14 discussed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Eight papers discussed the added value of performing intubation in a low-pressure operating room, mainly based on the SARS outbreak experience in 2003. Thirteen papers elaborated on the risks of intubation for health care providers and SARS-CoV-2, and 19 papers discussed this situation with other viruses. They conclude that there is significant evidence that intubation and extubation is a high-risk aerosol-producing procedure. No papers were found on the risk of SARS-CoV-2 and surgical smoke, although 25 papers did provide conflicting evidence on the infection risk of human papillomavirus, hepatitis B, polio, and rabies. No papers were found discussing tissue extraction or the deflation risk of the pneumoperitoneum after laparoscopic surgery.ConclusionsThere seems to be consensus in the literature that intubation and extubation are high-risk procedures for health care providers and that maximum protective equipment is needed. On the other hand, minimal evidence is available of the actual risk of contamination of health care providers during laparoscopy itself, nor of operating room pressure, surgical smoke, tissue extraction, or CO2 deflation. However, new studies are being published daily from current experiences, and society statements are continuously updated. There seems to be no reason to abandon laparoscopic surgery in favor of open surgery. However, the risks should not be underestimated, surgery should be performed on patients with COVID-19 only when necessary, and health care providers should use logic and common sense to protect themselves and others by performing surgery in a safe and protected environment.

Dynamical aspects of nanoparticle formation by wire explosion process

Copper nanoparticles (NPs) were produced by wire explosion process (WEP) and it was noted that the amount of energy (E) deposited on the wire and the ambient pressure play a major role on the size of particles formed. Dynamic diffusion and condensation processes of NPs formation by WEP were modelled. Calculations of critical size of embryo, activation energy and nucleation rate of the formation of NPs in WEP were made considering classical homogeneous nucleation theory. Decrease in critical size of nuclei and activation energy, increase in nucleation rate with high E (540 J) and low operating pressure (10 kPa) confirm the formation of small size NPs (26 nm). Different cooling rates due to unsymmetrical shape of the vapour cloud has been identified as the cause for generating mixed particle sizes. The qualitative analysis conducted in this work validates the obtained experimental results and can be used as a design tool for industrial apparatus to produce NPs in bulk.

Progress with development of foil and slot thermal transfer technology

Foil And Slot Thermal Transfer (FASTT) devices have a unique set of characteristics and the technology may have an important role in future thermal engineering. The absence of freezing and boiling issues, together with the potential for very wide operating temperature range from below 100 K to above 1000 K, as well as their use of low cost, environmentally friendly materials are among those features which have already been mentioned in literature. The geometry of FASTT devices is currently limited to planar or extrudable sections, however, such formats are found in a number of important applications, such as high power, high flux cooling of semiconductors.The core of any FASTT device is the slotted region within a thermally conductive material through which solid foils move and, in a similar fashion to fluids, carries heat away to a larger, lower flux zone where the heat may be dissipated by convection. This allows very high input cooling flux levels to be achieved. There are a number of differences between FASTT and pumped fluid heat transfer. “Equivalent” heat transfer coefficients comparable to those in pumped liquid systems can be obtained but at much lower media velocities (0.05 cf 3.00 ms−1). Narrow channel flow for liquids can be limited by viscosity and allowable operating pressure level. The thin solid foils used in FASTT can run with very low friction at foil to slot gaps below 10 µm, and with channel widths below 100 µm. This ensures low circuit parasitic losses and low pressure operation. The foils can provide both primary heat transfer as well as acting as the extended output surfaces in unsealed variants of these devices. This can remove the need for fluid channels/pipework and thus, potentially, reduce system mass.Limiting flux levels for simple air blast cooled finned arrays are considered, as are theoretical flux limits for FASTT devices, using a selection of foil material and gap media. Results from an unsealed prototype device are given which show that flux values of over 250 Wcm−2 at 70C temperature differences are possible with this type of device operating at room temperature, even in prototype form. Future proposals include sealed devices operating at cryogenic temperatures where the technology is predicted to show significant advantages over existing cooling systems.

A loose polyamide nanofiltration membrane prepared by polyether amine interfacial polymerization for dye desalination

It is crucial for fractionating dye/salt mixture in dyeing wastewater treatment. Herein, a polyamide nanofiltration (NF) membrane (PEA-TMC) for high efficient dye desalination was prepared through polyether amine (PEA) and trimesoyl chloride interfacial polymerization. Due to the large molecular size and hydrophilicity of PEA, the resulting NF membrane possessed a relatively loose membrane structure and good hydrophilicity, which improved membrane water flux and dye desalination performance. The influences of PEA concentration and reaction time on the NF performance were systematically investigated. Under the optimal conditions, the membrane exhibited a high water flux of 66.4 L m-2h−1 at low operating pressure (0.4 MPa), and showed a high methyl blue rejection (95.4%) and low NaCl rejection (16.4%) when nanofiltrated methyl blue/ NaCl mixture solution. Moreover, PEA-TMC membrane exhibited good stability in continuous operation and antifouling performance. These results disclosed the promising applications of PEA-TMC membrane in dye/salt separation process.

Enhanced Electrosynthetic Hydrogen Evolution by Hydrogenases Embedded in a Redox-Active Hydrogel.

Molecular hydrogen is a major high-energy carrier for future energy technologies, if produced from renewable electrical energy. Hydrogenase enzymes offer a pathway for bioelectrochemically producing hydrogen that is advantageous over traditional platforms for hydrogen production because of low overpotentials and ambient operating temperature and pressure. However, electron delivery from the electrode surface to the enzyme's active site is often rate-limiting. Here, it is shown that three different hydrogenases from Clostridium pasteurianum and Methanococcus maripaludis, when immobilized at a cathode in a cobaltocene-functionalized polyallylamine (Cc-PAA) redox polymer, mediate rapid and efficient hydrogen evolution. Furthermore, it is shown that Cc-PAA-mediated hydrogenases can operate at high faradaic efficiency (80-100 %) and low apparent overpotential (-0.578 to -0.593 V vs. SHE). Specific activities of these hydrogenases in the electrosynthetic Cc-PAA assay were comparable to their respective activities in traditional methyl viologen assays, indicating that Cc-PAA mediates electron transfer at high rates, to most of the embedded enzymes.

Recent Progress in Electrocatalysts for Acidic Water Oxidation

AbstractHydrogen is a clean and renewable energy carrier for powering future transportation and other applications. Water electrolysis is a promising option for hydrogen production from renewable resources such as wind and solar energy. To date, tremendous efforts have been devoted to the development of electrocatalysts and membranes for water electrolysis technology. In principle, water electrolysis in acidic media has several advantages over that in alkaline media, including favorable reaction kinetics, easy product separation, and low operating pressure. However, acidic water electrolysis poses higher requirements for the catalysts, especially the ones for the oxygen evolution reaction. It is a grand challenge to develop highly active, durable, and cost‐effective catalysts to replace precious metal catalysts for acidic water oxidation. In this article, an overview is presented of the latest developments in design and synthesis of electrocatalysts for acidic water oxidation, emphasizing new strategies for achieving high electrocatalytic activity while maintaining excellent durability at low cost. In particular, the reaction pathways and intermediates are discussed in detail to gain deeper insight into the oxygen evolution reaction mechanism, which is vital to rational design of more efficient electrocatalysts. Further, the remaining scientific challenges and possible strategies to overcome them are outlined, together with perspectives for future‐generation electrocatalysts that exploit nanoscale materials for water electrolysis.

Physical experiments and numerical simulations of viscosity reducer flooding for ordinary heavy oil

In order to overcome disadvantages of thermal recovery technologies such as high cost and air pollution, chemical flooding for ordinary heavy oil by viscosity reducer flooding was studied. The EOR mechanisms of viscosity reducer flooding to improve heavy oil recovery were studied by physical experiments and numerical simulation methods. First, the performance of the viscosity reducer was evaluated, then the injection characteristics and oil displacement performance were studied through core oil displacement experiments, the mechanism of oil recovery improvement by the viscosity reducer was studied through microscopic visualization experiments, and finally a comparison was made between indoor physical experimental results and numerical simulations. The results showed that the process of viscosity reducer flooding can form a stable oil-in-water emulsion. The process of water flooding can be divided into three stages: the starting pressure breakthrough stage, the rapid pressure decline stage, and the low pressure operation stage. Viscosity reducer flooding reduced the starting pressure gradient and the displacement pressure, while the oil recovery factor was increased by 12.4%, and the total recovery reached 46.6%. The main mechanism of improving oil recovery by a viscosity reducer is to reduce the crude oil viscosity and the residual oil saturation. By using the nonlinear mixing rule, the variation rule of crude oil viscosity with the viscosity reducer concentration was obtained, which can be directly applied to reservoir numerical simulations. A pilot test showed that the water cut was decreased and oil production was increased, which also reduced the injection pressure and gave all the production wells improved oil production.

Transverse magnetic field effects on spatial electron temperature distribution in a 13.56 MHz parallel plate capacitive discharge

The effect of a transverse magnetic field on spatial electron temperature Te distribution along the line joining the center of capacitively driven rectangular discharge plates, operated at 13.56 MHz in a push-pull configuration, has been presented. It is found that the electron temperature distribution is almost uniform at low operating pressure (1 Pa). However, as the background pressure increases, the electron temperature tends to peak near the discharge plates. The overall magnitude in Te is also found to increase throughout the volume on account of increasing the background pressure. This experimental observation has been qualitatively depicted by COMSOL Multiphysics® fluid simulation. A plausible explanation has been given to explain the rise in Te due to the combined effect of the magnetic field and background pressure in this setup.

Techno-economic assessment of an integrated biomass gasification, electrolysis, and syngas biomethanation process

Biological methanation (biomethanation) of biomass-derived syngas can be a promising alternative to catalytic methanation, due to its milder operating conditions, and could improve the feasibility of power-to-gas and syngas upgrading systems. However, the feasibility of integrating syngas biomethanation with other processes, i.e., electrolysis and gasification, has not been thoroughly assessed so far by the existing literature. In this study, we carried out the techno-economic analysis of such integrated system and we compared it with the production of pure hydrogen. The results indicate that the two processes could produce 0.39 Nm3 of bio-derived substitute natural gas (bSNG) or 0.07 kg of bio-hydrogen (bH2) per kg of dry biomass, respectively. The process cold gas efficiency associated with the produced bSNG is estimated at 50.6%, with a 97.4% input hydrogen utilization efficiency. For bH2, the cold gas efficiency is 36.6%, with 85% hydrogen utilization. Gasification and gas compression were identified as the unit operations with the highest energy demand in both processes. The minimum selling prices (MSP) of the two products were estimated at 2.68 €/Nm3 for bSNG and 15.35 €/kg for bH2. While delivery costs and a limited production capacity pose additional challenges to the development of bH2 production on decentralized gasification plants, bSNG production for grid injection could become a more feasible alternative under appropriate incentive schemes. Key optimization opportunities for such process rely on better heat integration, lower pressure operation, and the use of waste biomass as feedstock.

Plasma spray–physical vapor deposition toward advanced thermal barrier coatings: a review

Plasma spray–physical vapor deposition (PS–PVD) is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed. This technology bridges the gap between conventional thermal spray and vapor deposition and provides a variety of coating microstructures composed of vapor, liquid, and solid deposition units. The PS–PVD technique serves a broad range of applications in the fields of thermal barrier coatings (TBCs), environmental barrier coatings (EBCs), oxygen permeable films, and electrode films. It also represents the development direction of high-performance TBC/EBC preparation technologies. With the PS–PVD technique, the composition of the deposition unit determines the microstructure of the coating and its performance. When coating materials are injected into a nozzle and transported into the plasma jet, the deposition unit generated by a coating material is affected by the plasma jet characteristics. However, there is no direct in situ measurement method of material transfer and deposition processes in the PS–PVD plasma jet, because of the extreme conditions of PS–PVD such as a low operating pressure of ~ 100 Pa, temperatures of thousands of degrees, and a thin and high-velocity jet. Despite the difficulties, the transport and transformation behaviors of the deposition units were also researched by optical emission spectroscopy, observation of the coating microstructure and other methods. This paper reviews the progress of PS–PVD technologies considering the preparation of advanced thermal barrier coatings from the perspective of the transport and transformation behaviors of the deposition units. The development prospects of new high-performance TBCs using the PS–PVD technique are also discussed.

Efficient oil/saltwater separation using a highly permeable and fouling-resistant all-inorganic nanocomposite membrane

Although it is still a great challenge, developing oil-/water-separating membranes that combine the advantages of high separation efficiency, salty environments tolerance, and fouling resistance are highly demanded for marine oil spill cleanups and oil-/gas-produced water treatment. Here, we report a new type of all-inorganic nanostructured membrane, which is composed of titanate nanofibers and SiO2 particulate gel for efficient and stable oil/saltwater separation. The nanoporous and interconnected network structure constructed with titanate nanofibers is the key to ensure the high separation efficiency and high water flux of the new membrane. The SiO2 gel is used as a binder to offer mechanical flexibility and integrity for this type of all-inorganic membrane. The new membrane displays a high oil/water separation efficiency of above 99.5% with oil content in treated effluent lower than US environmental discharge standards (42 ppm) and high water permeation flux of 1600 LMH/bar under low operation pressure. The new membrane also demonstrates outstanding durability in the environment of different salinities, and it has a good resistance for oil fouling due to its excellent underwater superoleophobicity with an oil contact angle above 150 °. Most importantly, the underwater superoleophobic properties can be well maintained after being repeatedly reused. The excellent environmental durability, oil-fouling resistance, high separation efficiency, and facile fabrication process for this new type of membrane render great potential for industrial application in treating produced water.

Theoretical and Experimental Studies of a Digital Flow Booster Operating at High Pressures and Flow Rates

The switched inertance hydraulic converter (SIHC) is a new technology providing an alternative to conventional proportional or servo-valve-controlled systems in the area of fluid power. SIHCs can adjust or control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, flexible control, and insensitivity to contamination. In this article, the analytical models of an SIHC in a three-port flow-booster configuration were used and validated at high operating pressure, with the low- and high-pressure supplies of 30 and 90 bar and a high delivery flow rate of 21 L/min. The system dynamics, flow responses, and power consumption were investigated and theoretically and experimentally validated. Results were compared to previous results achieved using low operating pressures, where low- and high-pressure supplies were 20 and 30 bar, and the delivery flow rate was 7 L/min. We concluded that the analytical models could effectively predict SIHC performance, and higher operating pressures and flow rates could result in system uncertainties that need to be understood well. As high operating pressure or flow rate is a common requirement in hydraulic systems, this constitutes an important contribution to the development of newly switched inertance hydraulic converters and the improvement of fluid-power energy efficiency.