3rd Layer Research Articles

Electronic Metal‐Support Interaction Induces Hydrogen Spillover and Platinum Utilization in Hydrogen Evolution Reaction

The substantial promotion of hydrogen evolution reaction (HER) catalytic performance relies on the breakup of the Sabatier principle, which can be achieved by the alternation of the support and electronic metal support interaction (EMSI) is noticed. Due to the utilization of tungsten disulfides as support for platinum (Pt@WS2), surprisingly, Pt@WS2 demands only 31 mV overpotential to attain 10 mA cm‐2 in acidic HER test, corresponding to a 2.5‐fold higher mass activity than benchmarked Pt/C. The pH dependent electrochemical measurements associated with H2‐TPD and in‐situ Raman spectroscopy indicate a hydrogen spillover involved HER mechanism is confirmed. The WS2 support triggers a higher hydrogen binding strength for Pt leading to the increment in hydrogen concentration at Pt sites proved by upshifted d band center as well as lower Gibbs free energy of hydrogen, favourable for hydrogen spillover. Besides, the WS2 shows a comparably lower effect on Gibbs free energy for different Pt layers (‐0.50 eV layer‐1) than carbon black (‐0.88 eV layer‐1) contributing to a better Pt utilization. Also, the theoretical calculation suggests the hydrogen spillover occurs on the 3rd Pt layer in Pt@WS2; moreover, the energy barrier is lowered with increment in hydrogen coverage on Pt.

Electronic Metal-Support Interaction Induces Hydrogen Spillover and Platinum Utilization in Hydrogen Evolution Reaction.

The substantial promotion of hydrogen evolution reaction (HER) catalytic performance relies on the breakup of the Sabatier principle, which can be achieved by the alternation of the support and electronic metal support interaction (EMSI) is noticed. Due to the utilization of tungsten disulfides as support for platinum (Pt@WS2), surprisingly, Pt@WS2 demands only 31 mV overpotential to attain 10 mA cm-2 in acidic HER test, corresponding to a 2.5-fold higher mass activity than benchmarked Pt/C. The pH dependent electrochemical measurements associated with H2-TPD and in-situ Raman spectroscopy indicate a hydrogen spillover involved HER mechanism is confirmed. The WS2 support triggers a higher hydrogen binding strength for Pt leading to the increment in hydrogen concentration at Pt sites proved by upshifted d band center as well as lower Gibbs free energy of hydrogen, favourable for hydrogen spillover. Besides, the WS2 shows a comparably lower effect on Gibbs free energy for different Pt layers (-0.50 eV layer-1) than carbon black (-0.88 eV layer-1) contributing to a better Pt utilization. Also, the theoretical calculation suggests the hydrogen spillover occurs on the 3rd Pt layer in Pt@WS2; moreover, the energy barrier is lowered with increment in hydrogen coverage on Pt.

Study on recovery and utilization of cold energy for insulation design of liquid hydrogen tanks

Insulation design is one of the key technologies for Liquid Hydrogen (LH2) tanks. To enhance the insulation efficiency and energy utilization of the LH2, this study proposes a novel approach to enhance the insulation performance of LH2 tank and cold energy cascade utilization of LH2. Three Cryo-cooling Insulation Systems (CIS) with various insulation schemes are designed, analyzed and compared from the perspectives of insulation performance, consumption and energy utilization efficiency. An optimal insulation scheme among three CISs is identified and evaluated. Additionally, a dimensionless number (Ψ) is proposed to assess the insulation advantages of the CISs. And the insulation performance and economic feasibility of the system be effectively balanced. The findings reveal that the insulation performance of the proposed CIS outperforms previous insulation methods by a factor of 239.13. Among the schemes in three CISs, Schemes 2 (Position of CSs at 6th, 25th and 35th layers), Schemes 3 (Position of CSs at 10th, 40th and 45th layers), and Schemes 3 (Position of CSs at 3rd, 40th and 45th layers) exhibit superior insulation performance in Cases #1 (CIS of LN2-LAr), Cases #2 (CIS of R14-R170), and Cases #3 (CIS of R1150-R23). Notably, Case #1 achieves the highest insulation performance, showing improvements of 2.58 and 1.63 times over Case #2 and Case #3, respectively. However, the energy output in Case #1 is approximately 248.12 W, constituting 83.10 % and 71.60 % of Case #2 and Case #3, respectively. Case #1 demonstrates the highest specific energy output, with improvements of 30.12 % and 81.05 % compared to Case #2 and Case #3, respectively. In terms of the exergy utilization rate of each equipment, the exergy utilization rate of equipment in Case #1 is the highest among the three cases. The study underscore the feasibility of cold energy utilization for insulation, providing solutions for energy conversion and thermal management of LH2 tanks through cryo-cooling cascade utilization.

Multilayer Reconfigurable 3D Photonics Integrated Circuits Based on Deposition Method

AbstractPhotonics integrated circuits (PICs) can overcome the bottlenecks in communication capacity. 3D PIC technology is an attractive method for increasing density effectively and combining different materials on one chip for functional integration. In this study, a low‐cost and reconfigurable 3D integrated silicon photonics (SiPhs) platform is proposed fabricated by depositing polycrystalline silicon (poly‐Si) on crystalline silicon (c‐Si), which is patterned through deep ultraviolet (DUV) stepper‐based manufacturing process. The high mobility of poly‐Si ensures high‐speed and power‐efficient modulation. Based on the proposed 3D SiPhs platform, an 8 × 8 optical switch whose units are separated in different layers is fabricated and packaged. The switch shows average insertion losses of −13.98 and −15.86 dB, while working in “all‐cross” and “all‐bar” states, respectively. The crosstalk is lower than −19 and −11 dB for “all‐cross” and “all‐bar” states. Additionally, an overlayer switch located on the 1st and 3rd layers is proposed and experimentally demonstrated, which offers overlapping capabilities that are more compact compared with switches in a single‐layer platform. This validates the possibility of the large‐density integration scalability of the platform.

Strategy to Enhance Air Electrode Performance and Durability in Soe and Co-Soe Modes: Composite Electrode with a Gradually Changing Composition

Among the key challenges of the Solid Oxide Cell (SOC) is stable, long-term operation in electrolysis (SOE, Solid Oxide Electrolysis), and co-electrolysis (co-SOE) modes. Many factors impact the SOC’s lifespan, i.e., the chemical composition of the fuel and air electrode, the type of the cell, and working conditions (e.g., current density, temperature). Therefore, the development of high-performance and durable cells seems to be crucial, as SOE/co-SOE systems may play an important role in the ongoing transformation toward a climate-neutral economy (low-emission hydrogen production; efficient utilization of CO2and renewable energy) [1,2].One of the crucial degradation mechanisms of SOC in electrolysis/co-electrolysis mode is the delamination of the air electrode, caused by the accumulation of high oxygen partial pressure on the interphase of the electrolyte, the formation of additional phases, and/or reaction of voids/cracks in the electrolyte or buffer layer [2,3]. A strategy to mitigate the risk of air electrode delamination is to use composite electrode based on the buffer layer material (GDC- Gd0,1Ce0,9O2) and state-of-the-art electrode – LSC (La0,6Sr0,4CoO3-δ), as it will lower the effect of the thermal expansion mismatch between the electrode and buffer layer/electrolyte. Moreover, by manipulating the microstructure of the electrode, e.g., by introducing a pore-forming agent, it is possible to ensure fast and effective collection of oxygen generated during operation in the SOE/co-SOE mode on the air side (preventing potential differences leading to the stresses on the electrode-electrolyte interface).In this study, the electrochemical performance of solid oxide cells with a modified, gradually changing composite LSC-GDC air electrode was verified in electrolysis and co-electrolysis modes. The following air electrode compositions were proposed for cell preparation: type 1: 1st layer 50LSC:50CGO, 2nd layer: 75LSC: 25GDC, 3rd layer: LSC, type 2: 1st layer 75LSC:25CGO, 2nd and 3rd layers: LSC with PMMA as a pore former; type 3: 1st layer 75LSC:25CGO, 2nd and 3rd layers: 90LSC:10GDC, and type 4: 1st layer 85LSC:15CGO, 2nd layer: 90LSC:10GDC; 3rd layer: LSC with PMMA as a pore former. The proposed air electrode was tested at the single-cell level (cells size of 50 mm x 50 mm), and the most promising solutions were implemented in the SOC stack (a stack consisting of 3-5 cells with a size of 110 mm x 110 mm). The electrochemical analysis of the developed cells includes measurements of the j-V dependences and EIS spectra under different modes (SOE and co-SOE), various temperatures, current densities, and different gas flows delivered at the air side of the cell. The microstructure, morphology, and composition of the prepared cells and samples after testing were analyzed using SEM, SEM-EDS, and, for selected samples, the FIB-SEM method. The obtained results showed that by a gradually changing the electrode composition, specifically by reducing the GDC content in the electrode, it is possible to obtain a stable electrode (a strategy to prevent air electrode delamination) with high catalytic activity in both electrolysis and co-electrolysis modes. The composite GDC-LSC electrodes with various compositions seem to be promising air electrodes for SOE and co-SOE systems. The study achieves relatively high current densities compared to the SoA cells, with only negligible degradation changes observed after long-term testing (>300 h in single cell configuration). Acknowledgments The presented research was financially supported by: the National Centre for Research and Development, Poland, within project no. LIDER/1/0003/L-12/20/NCBR/2021, which focuses on research related to composite electrodes. Anna Niemczyk acknowledges support from the Foundation for Polish Science (FNP) through a scholarship from the START program. References B. Mogensen et al., Clean Energy 3 (2019) 175; DOI: 10.1093/ce/zkz023Hauch, P. Blennow, Solid State Ionics 391 (2023) 116127; DOI: 10.1016/j.ssi.2022.116127Subotić, C. Hochenauer, Progress in Energy and Combustion Science 93 (2022) 101011; DOI: 10.1016/j.pecs.2022.101011

Spatial and temporal variation of biomass density beneath drifting fish‐aggregating devices in the western and central Pacific Ocean

AbstractWe analyzed three‐dimensional (3‐D) spatial and temporal variation of biomass density associated with drifting fish aggregating devices (dFADs) in the western and central Pacific Ocean. Detection depth of dFAD echosounder buoys was divided into three layers, for estimation of biomass density in each layer based on detected water volume. Temporal variation and spatial distribution of biomass density in each layer were compared. Similarity of biomass density gravity center shifts in each layer were assessed using the dynamic time warping (DTW) regularization algorithm. Biomass density varied regularly over ~1 month, with the 2nd and 3rd layers delayed ~14 days compared to the 1st layer. Biomass distribution range and density values were higher in the 1st layer than the 2nd and 3rd layers, but locations of maximum biomass density were close. The distribution of biomass density gravity centers between adjacent water layers were similar, with gravity centers of the 2nd and 3rd layers shifted over time in relationd to the 1st layer. Our study demonstrated that the aggregation behavior of species from different water layers attracted by dFADs were related, and emphasized the necessity for ecosystem‐based fisheries management.

The effect of nanobubbles on Langmuir-Blodgett films

Nanobubbles (NBs) are classified in two distinct categories: surface and bulk. Surface NBs are readily observed using atomic force microscopy (AFM), while the existence of bulk NBs has been a subject of debate, conflicting with the diffusion theory's predictions. Current methodologies for identifying bulk NBs yield inconclusive results. In this study, Langmuir Blodgett (LB) technique and AFM, are utilized to visualize NB imprints on anionic, cationic and zwitterionic lipid films deposited on glass-slide substrates. Our analysis of Langmuir monolayers compression isotherms reveals the impact of bulk NBs on lipid monolayer development. AFM scans of the deposited lipid films consistently show NB imprints. Notably, cationic and zwitterionic film depositions exhibit NB formations from the 1st layer, whereas in anionic films, these formations are observed only after the 3rd layer. These results suggest that the origin of these imprinted formations may be attributed to bulk NBs.

OTP Based Device Control System

OTP based wireless system is the advanced version of key based locking system the problem with the earlier key-based locking system is that every time need to carry a key to unlock the lock there is a high risk of losing a key if key is lost then, break the locking system which also result in wastage of money and for old people it is difficult to open the key based lock and there can only be one unique key for different locks having different keys. In project advanced version OTP based lock is used with high security. In project there is 3 layers security system. If someone tries to access it will generate a random OTP which was send to owner mobile & display for fraction of seconds. If the person entered a wrong OTP, it will be alert alarm buzz & generate a new OTP again. After successful enter the correct OTP will enter in 2nd layer protection which was asking us to enter password. Finally, we need to verify our RFID tag at 3rd layer protection. So, by this way our project was very highly security system able to use at bank locker, Data rooms in companies, confidential areas etc

Interpretation of the Availability of Springs in Labuang Rano Village with a Geophysical Approach

Geologically speaking, Labuang Rano Village, Mamuju City area is composed of rocks from the Adang Volcano Formation. Based on the results of the site survey, it was found that there is a spring with a slight discharge. The emergence of these springs is not yet known, so further analysis is needed. An approach used to determine subsurface conditions is the geophysical approach, especially the geoelectric method. This study aims to analyse the subsurface geological conditions using geoelectric to find the factors that influence the emergence of springs. Geoelectrical measurements, observations of rock outcrops, and the findings of previous research are used as data sources. The results of the analysis show that the subsurface geological conditions consist of 3 layers. The topmost layer is tuff rock, the 2nd layer is volcanic breccia and the 3rd layer is andesite rock. Based on the resistivity cross-section, it can be seen that there is a fracture that cuts vertically in the tufa rock layer from a depth of 13 m to the surface in a northeast-southwest direction. Thus, it can be concluded that the emergence of springs at the study site was caused by a fracture that cut the tufa rock layers vertically from a depth of 13 to the surface. The fracture which is the medium for groundwater to emerge onto the land surface forms a spring.

Monolithic 3D Integration of Analog RRAM-Based Computing-in-Memory and Sensor for Energy-Efficient Near-Sensor Computing.

In the era of the Internet of Things, vast amounts of data generated at sensory nodes impose critical challenges on the data-transfer bandwidth and energy efficiency of computing hardware. A near-sensor computing (NSC) architecture places the processing units closer to the sensors such that the generated data can be processed almost in situ with high efficiency. This study demonstrates the monolithic three-dimensional (M3D) integration of a photosensor array, analog computing-in-memory (CIM), and Si complementary metal-oxide-semiconductor (CMOS) logic circuits, named M3D-SAIL. This approach exploits the high-bandwidth on-chip data transfer and massively parallel CIM cores to realize an energy-efficient NSC architecture. The 1st layer of the Si CMOS circuits serves as the control logic and peripheral circuits. The 2nd layer comprises a 1k-bit one-transistor-one-resistor (1T1R) array with InGaZnOx field-effect transistor (IGZO-FET) and resistive random-access memory (RRAM) for analog CIM. The 3rd layer comprises multiple IGZO-FET-based photosensor arrays for wavelength-dependent optical sensing. The structural integrity and function of each layer are comprehensively verified. Furthermore, NSC is implemented using the M3D-SAIL architecture for a typical video keyframe-extraction task, achieving a high classification accuracy of 96.7% as well as a 31.5× lower energy consumption and 1.91× faster computing speed compared to its2D counterpart.

Human decision-substitutable chemometric identification of pixel shrinkage in OLEDs using secondary ion mass spectrometry

Secondary ion mass spectrometry (SIMS)-based depth profiling of organic light-emitting diode (OLED) samples composed of multiple layers is a useful analytical tool for identification of pixel shrinkage, which is a frequent defect occurring in OLED production. As an alternative to engineer-based defect identification, which is time-consuming and occasionally suffers from person-to-person discrepancies, a chemometric analysis scheme utilizing the whole SIMS dataset of the OLED sample has been explored in this study. Initially, all the depth-profiled spectra of each sample were assigned (classified) into the corresponding layers (groups) using a Gaussian mixture model (GMM), and the subsequent average spectra of each layer were used for layer-by-layer comparisons. Then, a one-class support vector machine (OC-SVM) was adopted for defect identification, and principal component (PC) scores of the spectra in each layer were used as the inputs for OC-SVM. The occurrence of defects in the 3rd layer was clear in the PC score domain, and the accuracy obtained by predicting the external test samples was 97.4%. Moving forward, the identification of potential peaks significantly contributing to the defect could be valuable clues to track the causes of defects (trouble shooting) during production. Kernel density estimation (KDE) was adopted for this purpose, and the top nine peaks with the lowest p-values (most significant contributions) were finally provided.

Theoretical study of MoSi2/TiSi2 disilicide nanocomposites with vacancies and impurities

Research on disilicide nanocomposites, as modern materials with promising technological applications, is very desirable in these days. Our ab initio analysis concentrates on the C11b (tetragonal) MoSi2/C54 (orthorhombic) TiSi2 nanocomposites containing 14 types of interfaces formed by planes with similar arrangements (i.e. (110) planes in the C11b and (100) planes in the C54 disilicide). The most stable nanocomposites are MoSi2(AC)/TiSi2(DACB) with interfaces CD and BA and MoSi2(AD)/TiSi2(CADB) with interfaces DC and BA, both with the formation energy (related to standard element reference states) equal to −0.615 eV.atom−1 and with the lowest interface energies. In the most stable and one higher-energy interface, the effect of the impurities (Al, Si) and vacancies on the stability and structure arrangement was investigated. It turned out that: (i) Al (Si) impurities occupy Si (Ti) positions in MoSi2 (TiSi2) in the 2nd and 3rd (and 4th) layer from the interface; (ii) the interfacial Si vacancy is the most stable having the formation energy of 2.568 eV.Va−1; (iii) the least destabilising divacancy is of the Si-Si type, and (iv) Si and Al impurities simplify the formation of vacancies. As there is very little experimental information on the structure and properties of these interfaces, most of the present results are theoretical predictions which may motivate future experimental work.

Design of triple-layer films with blackseed protein as dispersion or emulsion

The aim of study was to produce the blackseed protein for applications as a protein dispersion alone or an emulsifier to design of multi-layer film based on furcellaran and chitosan. The protein extraction of blackseed by-product resulted in a blackseed by-product protein isolate (BBPI) with a yield of 73% protein. The obtained BBPI resulted in a high polyphenols content (1543 mg/ml), antioxidant property (DPPH, 67%) and emulsification properties (encapsulation up to 96%), leading to a stable emulsions at pH 10 and 12. For the first time, innovative, active triple-layer films have been developed in the 1st furcellaran layer with BBPI stabilised emulsion or BBPI aqueous extract alone, followed by a 2nd layer of furcellaran and citric acid matrix, and a 3rd layer of chitosan and gelatin matrix. Compared to the control, the tested films showed improved the water behaviour, UV–Vis barrier and increased antioxidant activity for the DPPH parameter (>70%).

Study on the seismic response of new staggered story isolated structure under different parameters

The new staggered story isolated structure is developed according to the base-isolated structure and the mid-story isolated structure. Quantitative calculation and evaluation of seismic damage are very important for structural safety. In this paper, the seismic damage evaluation of a new staggered story isolated structure is studied by numerical simulation and damage index calculation. A new staggered story isolated structure is established, and the effects of different layers and different chassis areas on the seismic response of the structure are studied. When the position of the bottom isolated layer stays the same, the upper isolated layer is set at different layers, which is set to the top of the 3rd, 6th and 9th layers. When the upper isolated layer keeps at the top of the 3rd layer, the chassis area is set at a different area, which is 26 m × 26 m, 36 m × 36 m and 46 m × 46 m. The results show that the new staggered story isolated structure has good isolated effects under the ground motion. For the structure set upper isolation layer is lower, the inter-layer shear force, inter-layer acceleration and inter-layer displacement are reduced. The energy dissipation effect of the structure improves. The core tube is less damaged and the plastic hinge is smaller. With the increase of chassis area, the isolated effect of the part above the upper isolated layer is good, while the shear force and acceleration of the part below the upper isolated layer of the structure increase, the damage at the core tube changed little and the appearance of the plastic hinge increased. Under earthquakes, with the change in position of the upper isolated layer and the area of the chassis of the new staggered story isolated structure, the displacement, tensile stress and compressive stress of the isolated bearing still meet the requirements of the standard.

Factors controlling organic matter accumulation in the Longmaxi Formation shale, Changning area, South Sichuan Basin

Based on total organic content (TOC) tests and major-trace element test data, this study examined organic matter accumulation and controlling factors of the Longmaxi Formation shale in the Changning area, southern Sichuan Basin. The results showed that (1) TOC content of the Long11 submember (S1l11) shale was between 0.46% and 8.35%. Vertically, TOC revealed a ‘sandwich cake’ pattern with a high TOC content concentrated in the 1st layers of Long11 submember (S1l11–1) and 3rd layers of Long11 submember (S1l11–3) and a lower TOC content in the 2nd layers of Long11 submember (S1l11–2) and 4th layers of Long11 submember (S1l11–4). Spatial distribution of TOC showed variations and migration in S1l11. (2) S1l11 shale TOC showed a logarithmic correlation with sedimentary environment index, negative correlation with terrigenous influx, and complex correlation with paleoproductivity. (3) Factors controlling organic matter accumulation were mainly redox conditions, followed by paleoproductivity and terrigenous input in Changning area. When the paleoproductivity index (Babio) was less than 2200 μg/g, the redox conditions was the controlling factor of organic matter accumulation. On the contrary, it is ultrahigh paleoproductivity. Vertically, organic matter accumulation mode evolved from “preservation conditions” to “productivity–preservation conditions synergy mode” to “productivity mode”. (4) An anoxic condition was the basis of organic matter accumulation. Medium–high paleoproductivity was the key to organic matter accumulation. These study results are expected to contribute to shale gas exploration and development.

Behavior of Reinforced Gypseous Soil Embankment Model under Cyclic Loading

The construction of embankment for roadway interchange system at urban area is restricted due to the large geometry requirements, since the value of land required for such construction is high, and the area available is limited as compared to rural area. One of the optimum solutions to such problem is the earth reinforcement technique which requires a limited area for embankment construction. Gypseous soil from Al-Anbar governorate area was obtained and subjected to various physical and chemical analysis to determine it is properties. A laboratory model box of 50x50x25 cm was used as a representative embankment; soil has been compacted in five layers at maximum dry density (modified compaction) and an aluminum reinforcement strips were introduced between layers. The model was subjected to cyclic loading and the vertical and lateral deformations were detected at different stages of loading cycles using LVDT. The reinforced soil embankment under soaking condition exhibited vertical settlement at the top surface was (12.55 mm) while the lateral displacements at (1st, 3rd layer) were (2.18, 1.32) mm respectively at (47 load cycles).For reinforced gypseous soil, embankment without soaking cured for 24 hours, the Number of load cycles was found to be (165) loading cycles with vertical displacement (9.12 mm), that means an improvement of 59%. Accordingly, the lateral displacement in 1st and 3rd layers were (3.28, 2.59) mm respectively which observes improvement by (28% and 5%) respectively. The rates of improvement are taken with respect to the reinforced pure dry soil sample.

Equilibrium configurations and electronic structure of fullerene ultrathin films on SrTiO3(0 0 1) surface

Ultrathin fullerene (C60) films on various metal and semiconductor substrates have been intensively studied but not yet on a perovskite oxide substrate. Using scanning tunneling microscopy and spectroscopy, we investigated the molecular arrangement and electronic structure of C60 ultrathin films grown on a SrTiO3(001) surface. Subject to strong coupling and weak screening from the substrate, the monolayer C60 exhibit short-range ordered molecular arrangement with disordered molecular orientation and a substantially large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap (∼4.1 eV). In contrast, C60 in the 2nd and 3rd layers are self-assembled into hexagon lattices with a quasi-(2 × 2) superstructure resulted from the arrangement of molecular orientations showing a chiral pinwheel structure. The HOMO-LUMO gap of the multi-layer C60 further expands to ∼ 4.6 eV, very close to that of gas-phase C60, indicating a negligible inter-layer screening effect.

Magnetically Separable Humic Acid-Chitin Based Adsorbent as Pb(II) Uptake in Synthetic Wastewater

Modification of humic acid (HA) from the peat soil of Jambi province, Indonesia with chitin and magnetite to form Fe3O4/HA-chitin has been successfully carried out. The successful synthesis was identified from characterization with functional group analysis, crystal analysis, magnetic strength measurement, and morphological and elemental analysis. The application of Fe3O4/HA-chitin to adsorb Pb(II) ion was analyzed using the Lagergren, Ho, Santosa, and RBS kinetics models (kinetics study) and the Langmuir, Freundlich, Dubinin-Radushkevich (DR), and Temkin isotherm model (isotherm study). The kinetics study followed the Ho model (pseudo-second order) with R2 and kHo of 0.9997 and 10264.59 g/mol min, respectively. The results of the data applicable to the Freundlich model showed that several sites were capable of multilayer adsorption (B) with a large enough adsorption capacity of 929.19 mg/g (about 28 times higher than the monolayer adsorption of Langmuir data). However, the outermost layer had a feeble adsorption energy of 0.51 kJ/mol, as measured by Temkin's adsorption energy. In the layer between the first layer (Langmuir) and the outermost layer (Freundlich), the DR isotherm was measured at a capacity of 104.87 mg/g (qD, the 3rd layer of the first layer) the adsorption energy was measured at 12.91 kJ/mol. A cross-study on the prediction of adsorption energy using the Santosa and RBS kinetics models showed that the RBS model had an adsorption energy value (26.45 kJ/mol) that was closer to the adsorption energy value of the Langmuir isotherm (27.55 kJ/mol).

Heat transfer and performance enhancement investigation of biomimetic honeycomb gas coolers in transcritical CO2 heat pumps

CO2 air source heat pump heating technology has characteristics of strong adaptability to outdoor temperature in cold areas and high outlet temperature, which is widely used in heating and domestic hot water supply. A gas cooler is one of the crucial components in CO2 heat pump systems, while its performance and different structural forms will directly affect the performance of the whole CO2 heat pump system. In order to improve its heat transfer efficiency, a biomimetic honeycomb gas cooler is proposed in this paper, the steady-state simulation model of the biomimetic honeycomb gas cooler is established, and the reliability of the model is verified by experimental data. In addition, the effect of structural parameters and operating parameters on the heat transfer performance is studied, also the heat transfer performance of the biomimetic honeycomb gas cooler is compared with that of the internal spiral tube gas cooler and triple tube-in-tube gas cooler. The results show that the performance of the biomimetic honeycomb gas cooler can be effectively improved by reducing the water flow rate. Under the same working condition, the performance evaluation criteria1 of the 1st, 2nd and 3rd layer biomimetic honeycomb gas cooler s are about 193.4%, 239.9% and 357.0% higher than that of the internal spiral tube gas cooler, and about 197.2%, 205.9% and 237.7% higher than that of triple tube-in-tube gas cooler. This research is helpful to provide the reference for the design and optimization of this type of gas cooler and is conducive to the popularization and application of CO2 air source heat pumps.

Assessment of the multilevel correlations of the pollution indicators and lithological vulnerabilities in a passive limestone mining and cement producing environment.

This study presents the assessment of the air, soil, and water quality within the residential communities around two passive limestone mining/cement factories. The associations between the pollutants were tested across the media, within each medium, between the layers, and between two groups of the communities. The mean values for the PM1.0, PM2.5, and PM10 were 65.8 µgm-3, 50.1, and 73.7, respectively, in the air; for the Mn, Fe, Cu, Zn, Cr, K-40, U-238, and Th-232 were 0.433g/kg, 8.950, 0.005, 0.054, 0.104, 161.57Bq. kg-1, 61.10, and 15.85, respectively, in the topsoil; 0.365g/kg, 8.259, 0.004, 0.029, 0.057, 71.84Bq. kg-1, 16.37, 4.66, respectively, in the subsoil; and for the Mn, Fe, and Zn were 0.190, 1.499, and 0.256mg/l, respectively, in the water. The PM10, Fe, and K-40 were the most abundant pollutants. The Co and Mn, Zn and Cu, Fe and Cu, the absorbed dose rate (ADR) and K-40, and ADR and U-238 correlated significantly. Though the Ibese group was more polluted than the Ewekoro group, the generally low levels of the pollutions were confirmatory of the earlier suspicions of the mining/production activities. The 2nd lithological layer at 0.5 to 1.9m depths or the 3rd lithological layer at 1.1 to 7.69m depths for the Ibese group and the 1st layer at the surface or the 2nd layer at 0.5m depth for the Ewekoro group are protective layers for the groundwater that must not be exploited, given the three classes of groundwater vulnerability indices observed in the area.