Hexagonal Matrix Research Articles

Fluorescence visualization dynamics of carbonated water injection processes in homogeneous glass micromodels

Understanding the flow behavior of oil–water phases in porous media is crucial for revealing the kinetic mechanisms underlying oil–water movement. In this study, we designed and constructed a fluorescence visualization experimental platform for carbonated water injection (CWI). We evaluated the effects of nine distinct injection rates on oil production and CO2 sequestration capabilities using three types of homogeneous porous structure micromodels. The microscale oil–water seepage behavior at the pore scale was also explored. The experimental results indicate that optimally increasing the injection rate can improve displacement efficiency, whereas excessively high rates may lead to viscous and capillary fingering. The geometry of the micromodels, particularly the hexagonal matrix, demonstrates potential advantages in enhancing oil displacement due to its uniform flow paths. The capillary number (Ca) significantly influences oil droplet capture behavior within micromodels. For instance, micromodel A captures the largest ganglion area at low Ca values, with a noticeable reduction in average ganglion area as Ca increases. Conversely, micromodels B and C exhibit similar trends in ganglion size variation at high Ca values, suggesting a more uniform impact of pore structure on oil droplet capture behavior. At elevated Ca values, capillary forces exert a more uniform and controlled effect on oil droplet capture and release, minimizing size variability. Additionally, the injection rate plays a critical role in CO2 sequestration, with higher rates promoting convective mixing between CO2 and reservoir fluids, thereby enhancing dissolution and storage efficiency. The complexity of the pore structure, characterized by the presence of micropores and macropores, affects the dissolution kinetics and mobility of CO2, influencing sequestration efficiency. These experimental findings provide valuable insights into the dynamics of oil–water motion and the potential for enhanced oil recovery (EOR) and CO2 storage, offering essential guidance for optimizing CWI strategies in the petroleum industry.

Manufacturing of hexagonal cross-section thermoplastic matrix composite parts with automatic filament winding system

Thermoplastic filament winding is a flexible manufacturing method typically used in the production of cylindrical composite structures, allowing for in-situ consolidation without the need for a second consolidation step. The objective of this study is to produce non-cylindrical geometries, typically manufactured using thermoset matrix composites according to the literature, using the thermoplastic filament winding process. For this purpose, glass fiber (GF) reinforced polypropylene (PP) prepreg tapes were used to produce hexagonal cross-section thermoplastic composite parts. The critical process parameters; hot-air heater nozzle temperature, compression roller pressure, the linear speed of mandrel rotation, and corner radius of the mandrel, were determined using the Taguchi experimental design method. The interlaminar shear strength (ILSS) and maximum compressive strength (σmax) values were obtained as 211 MPa and 49.40 MPa as maximum, respectively. ANOVA analysis showed that the corner radius had the most significant impact on ILSS, while mandrel rotation speed and temperature were critical for σmax.

Synthesis of Copper Supported on Natural Rubber-derived Mesoporous Carbon/Silica Composite for Efficient Adsorption of Caffeine

Caffeine (CAF) removal from water resources is important because it is widely distributed and can be toxic to aquatic life. The copper supported on mesoporous carbon/silica composite (Cu/MCS) in this research was developed as a novel adsorbent to remove caffeine from aqueous solutions. The Cu/MCS material was prepared in two steps. The first step was the preparation of a precursor consisting of copper and natural rubber distributed inside a hexagonal mesoporous silica matrix (Cu/NR/HMS). Then, the composite was carbonized at high temperature under inert gas conditions to obtain Cu/MCS material. The amount of Cu loading in the MCS structure was studied. The Cu/MCS composites revealed a high level of copper distribution incorporated into the mesoporous carbon/silica framework as confirmed by Powder X-ray diffraction (XRD) and Scanning Electron Microscope and Energy Dispersive X-ray Spectrometer (SEM-EDS). The Cu/MCS materials possessed a high specific surface area (523–748 m2 g−1), large pore volume (0.80–0.86 cm3 g−1) and mesoporous diameter (3.07-3.30 nm). Fourier Transform Infrared Spectroscopy (FT-IR) and CHN analysis revealed a high amount of carbonaceous species dispersed in the Cu/MCS material. The Cu (0.010)/MCS, with copper loading of 1 mmol/g, revealed good properties for CAF removal when compared to other series of Cu/MCS adsorbents. Moreover, the Cu (0.010)/MCS composite exhibited the maximum adsorption capacity for CAF as 55.8 mg/g.

CTS—A new X-ray facility for imaging and tomography @ XlabF

X-ray based techniques are widely used in the world. However, high interactions between radiation and matter causes a not so easy radiation handling by optical devices. In the last 30 years, the studies concerning novel advanced material have fostered the development of several solutions for more efficient X-ray setup, necessary to perform high spatial resolution analysis in spectroscopy as well as for imaging techniques applied in Medicine/Pharmacology, Cultural Heritage, Geology and Environment, Electronics, Aerospace, etc.Recent results (principally in three main fields, such as high resolution X-ray Imaging, micro X-Spectroscopy and micro Tomography) obtained at XLab-Frascati (XlabF) were previously discussed while very recently, a new experimental setup, dedicated for High Resolution X-ray Imaging and μ-Tomography, was developed as a part of Italian Premiale project, called ”Computed Tomography Station” (CTS). This apparatus is equipped with a micro-focusing source (5μm on the anode), high precision mechanics and high-resolution CCD detector (10.4μm per pixel), so as through the phase retrieval technique, we can reach the estimated resolution of less than 1μm. The CTS experimental setup was commissioned ad the beginning of 2023 and it is already ready to be opened for internal and external users.In this work, we will show the last results concerning our new experimental setup, related to the analysis of a glass capillary, with different geometrical distances, and two organic samples entrapped in matrix amber. Starting from these results, the next step is to use modern polycapillary optics as a grating interferometric hexagonal matrix for a better phase-contrast resolution.

Алгоритм лечения далеко зашедшей пролиферативной диабетической ретинопатии

Purpose. To develop an algorithm for the treatment of patients with advanced proliferative diabetic retinopathy with the determination of the stages of laser and surgical methods and evaluate its effectiveness. Material and methods. The study group included 38 patients (38 eyes) with type 1 diabetes mellitus (21 patients) and type 2 diabetes mellitus (17 patients, 16 of them with the insulin-requiring form of the disease). Patients age ranged from 24 to 75 years (41±8.6 years) old. All patients underwent staged treatment. Primary subtotal three-port 27 G vitrectomy was performed. Transpupillary patterned panretinal laser coagulation was performed at 1,5–2 months after the first stage of treatment. Panretinal laser coagulation was performed with a hexagonal matrix pattern with a laser spot diameter of 300 µm, exposure time of 30 ms on an Integre Pro Scan laser device (Ellex, Australia) with a wavelength of 561 nm using a panfundus lens. In cases of gas-air tamponade, panretinal laser coagulation was performed according to the same parameters in two sessions with an interval of 1–2 months between them, the average number of coagulates per session was 1053±107 applications. As the third stage of treatment, 1,5–2 months after panretinal laser coagulation, those patients whose vitreal cavity was tamponed with silicone oil underwent vitrectomy with the removal of silicone oil and it's replacement with a balanced solution. Results. The total number of treatment steps in the observation group (n=34) ranged from 1 to 5 and averaged 3±0.97. The time from primary vitrectomy followed by patterned panretinal laser coagulation to silicone oil removal was at average 3.7±0.48 months. Performing primary subtotal vitrectomy as the first stage of combined treatment made it possible achieve retinal attachment and its visualization throughout, to perform surgical intervention without massive endolaser coagulation, which reduced the duration of surgery and accelerated postoperative rehabilitation. The subsequent transpupillary panretinal laser coagulation of the retina in the pattern mode provided a dosed precision effect on the retina and made it possible perform the laser stage of treatment in one session. Conclusion. A step-by-step algorithm, including primary subtotal vitrectomy followed by simultaneous transpupillary pattern laser coagulation of the retina, is effective and safe in the treatment of proliferative diabetic retinopathy complicated by hemophthalmos. Key words: proliferative diabetic retinopathy, treatment algorithm, surgical treatment, laser treatment, vitrectomy, pattern laser coagulation

Structural complexity in the apparently simple crystal structure of Be2Ru.

The structural features of the hexagonal layered crystal structure of Be2Ru (a = 5.7508(3) Å, c = 3.0044(2) Å, space group P -62m) were investigated by single crystal X-ray diffraction and transmission electron microscopy (TEM). The residual electron density and high-resolution TEM images show that the real structure can be described as an intergrowth of the main hexagonal matrix of the Fe2P type with minor orthorhombic inclusions of its stacking variants. Such atomic arrangement is stabilized by the charge transfer from Be to Ru and by a system of polar three- and four-atomic bonds involving both components. The calculated electronic density of states (DOS) of Be2Ru revealed, contrarily to typical intermetallic compounds, a pseudo gap (dip) in the vicinity of the Fermi level. The temperature dependence of the electrical resistivity of Be2Ru shows metal behavior in agreement with the non-zero DOS at the Fermi level.

Multimode fluorescence intensity ratio thermometer based on synergistic luminescence from Eu3+ to Mn4+ of SrTiO3:Eu3+-ZnTiO3:Mn4+ nanocomposites

SrTiO3:Eu3+-ZnTiO3:Mn4+ nanocomposites were successfully synthesized to obtain highly sensitive optical thermometers. The synthesized SrTiO3:Eu3+ was cubic perovskite structure, and the synthesized ZnTiO3:Mn4+ was cubic perovskite structure accompanying with hexagonal ilmenite structure. The results of X-ray diffraction and Fourier transform infrared spectra suggested that the mixture of SrTiO3:Eu3+-ZnTiO3:Mn4+ nanophosphors had no obvious change in the structure after heat treatment at 800 °C. The photoluminescence intensity of Eu3+ in SrTiO3 phosphors revealed a stable temperature dependence, while that of Mn4+ in ZnTiO3 phosphors revealed a sharp temperature dependence. The emission band ranging from 650 nm to 800 nm were separated into two bands centered at 690 nm and 714 nm, which were assigned to 4T2g→4A2g and 2Eg→4A2g transitions of Mn4+ ions in cubic perovskite and hexagonal ilmenite ZnTiO3 matrix, respectively. The maximum relative sensitivity revealed a dependence on the molar ratio between SrTiO3 and ZnTiO3. The maximum value of 3.3 %K−1 was achieved for the composites with the molar ratio of 1:3 between SrTiO3:Eu3+ and ZnTiO3:Mn4+ nanophosphors, which was higher than that of the composites before heat treatment, 3.1 %K−1. The results suggested the potential application in optical temperature probes for the composites.

Color optimization of a core–shell nanoparticles layer using machine learning techniques

Neural networks were recently introduced in the field of nanophotonics as an alternative and powerful way to obtain the non-linear mapping between the geometry and composition of arbitrary nanophotonic structures on one hand, and their associated properties and functions on the other. Taking into account the recent advances in the application of the machine learning concept to the design of nanophotonic devices, we employ this tool for the optimization of photonic materials with specific color properties. We train a deep neural network (DNN) to solve the inverse problem, i.e., to obtain the geometrical parameters of the structure that best produce a desired reflected color. The analyzed system is a single layer of core–shell spheres composed of melanin and silica embedded in air, arranged in a hexagonal matrix. The network is trained using a dataset of the three CIE 1976 (L*a*b*) color coordinates obtained from the simulated reflectance spectra of a large set of structures. The direct problem is solved using the Korringa–Kohn–Rostoker method (KKR), widely applied to calculate the optical properties of sphere composites. The color optimization approach used in this work opens up new alternatives for the design of artificial photonic structures with tunable color effects.

Crystallography of the martensitic transformation between Ni2In-type hexagonal and TiNiSi-type orthorhombic phases

• A bulk sample with small amounts of orthorhombic phases distributed in hexagonal matrix is obtained. • The orientation relationship between hexagonal and orthorhombic structures is [ 4 2 ¯ 2 ¯ 3 ] h / / [ 120 ] o & ( 01 1 ¯ 0 ) h / / ( 001 ) o . • The habit plane of the hexagonal-orthorhombic transformation is { 2 ¯ 1 1 3.26 } h . • The strain that induce the transformation from hexagonal to orthorhombic structures is revealed. MnMX (M = Co or Ni, X = Si or Ge) alloys, experiencing structural transformation between Ni 2 In-type hexagonal and TiNiSi-type orthorhombic phases, attract considerable attention due to their potential applications as room-temperature solid refrigerants. Although lots of studies have been carried out on how to tune this transformation and obtain large entropy change in a wide temperature region, the crystallography of this martensitic transformation is still unknown. The biggest obstacle for crystallography investigation is to obtain a bulk sample, in which hexagonal and orthorhombic phases coexist, because the MnMX alloys will fragment into powders after experiencing the transformation. For this reason, we carefully tune the transformation temperature to be slightly below 300 K. In that case, a bulk sample with small amounts of orthorhombic phases distributed in hexagonal matrix is obtained. Most importantly, there are no cracks between the two phases. It facilities us to investigate the microstructure using electron microscope. The obtained results indicate that the orientation relationship between hexagonal and orthorhombic structures is [ 4 2 ¯ 2 ¯ 3 ] h / / [ 120 ] o & ( 01 1 ¯ 0 ) h / / ( 001 ) o and the habit plane is { 2 ¯ 1 1 3.26 } h . WLR theory is also adopted to calculate the habit plane. The calculated result agrees well with the measured one. Our work reveals the crystallography of hexagonal-orthorhombic transformation for the first time and is helpful for understanding the transformation-associated physical effects in MnMX alloys.

Green Synthesis of Silver Nano Particles Derieved from Leaf Extract of Syzygiumcuminii (SNSC) – to Evaluate Antibacterial Activity

Synthesis of metals nanoparticles from the plant or plant extracts has emerged as an important alternative to the chemical method. The biological approach to the synthesis of nanoparticles has many advantages such as non-elaborative process, no multiple purification steps, no need of intracellular synthesis and dosenot require maintenance of microbial cell cultures. Medicinal plants and green synthesis of silver nanoparticles (AgNPs) have proven to be good sources of agents effective in the treatment of various diseases. The present study focuses on the green synthesis of SNSC, silverna noparticles (AgNPs) from leaf extract of Syzygiumcuminii in order to evaluate the antibacterial properties of this extract and synthesized AgNPs. The characterization of the Synthesized nanoparticles (SNSC) was determined using UV-VIS spectroscopy, TEM,X ray diffraction and FTRI studies, silver nanoparticles (AgNPs) showed absorption peak at 470 nm in aqueous medium in UV-VIS spectrum. TEM analysis shows themorphology of AgNPs as a hexagonal matrix with average particle size of about 50 nm. XRD analysis displays the crystalline structure of AgNPs.FTIR analysis shows that amide groups present in proteins are dominant reducing agents and play an important role in the bio reduction of Ag+ ions to Ag0. The synthesized silver nanoparticles from leaf extract of Syzygiumcuminii(SNSC) showed antibacterial activity against common clinical pathogens. Owing to the remarkable potential antibacterial activity against common pathogenic microorganisms, the synthesized AgNPs derieved from SNSCcan have potential for development in medical applications in the future..

Investigation of δ zirconium hydride morphology in a single crystal using quantitative phase field simulations supported by experiments

• A quantitative phase field model of the α -Zr/ δ -ZrH system was developed. • Elastic anisotropy influences hydride shape, hydrogen distribution, and hydride interaction. • Circumferential stacking of nanoscale hydrides is predicted. • The model’s predictions successfully compare with experimental observations. In light water nuclear reactors , waterside corrosion of the cladding material leads to the production of hydrogen, a fraction of which is picked up by the zirconium cladding and precipitates into brittle hydride particles. These nanoscale hydride particles aggregate into mesoscale hydride clusters. The principal stacking direction of the nanoscale hydrides precipitated in the cladding tube changes from circumferential in the absence of applied stress to radial under circumferential applied stress. A quantitative phase field model has been developed to predict the hydride morphology observed experimentally and identify the mechanisms responsible for nanoscale hydride stacking. The model focuses on nanoscale hydride precipitation in a single zirconium grain with a detailed description of the anisotropic elastic contribution. The model predictions concerning the shape, orientation, and stacking behavior of nanoscale hydride are analyzed and compared with experimental observations. The model accurately accounts for the experimentally observed elongated nanoscale hydride shape and the stacking of hydrides along the basal plane of the hexagonal zirconium matrix. When investigating the role of applied stress in hydride morphology, the model challenges some of the mechanisms previously proposed to explain hydride reorientation. Although hydride reorientation has been hypothesized to be caused by a change in nanoscale hydride shape, the current study shows that these mechanisms are unlikely to occur.

Electrochemical corrosion and erosive wear behaviour of microwave processed WC-10Co4Cr clad on SS-316

WC-10Co4Cr cladding over an austenitic stainless steel (SS-316) was fabricated by using a cost- effective microwave technique. Cladding was performed with 1.20 kW power and a frequency of 2.45 GHz in an industrial microwave oven. The XRD surveillance reveals a cluster of carbide phases adjunct to W-Cr-Fe based hexagonal matrix. The SEM examination reveals a solid microstructure and a homogeneous reinforced skeleton with porosity measures of less than 1% in the clad specimen. Tungsten (W) distributed equally in matrix and carbides, resulting in bulk hardness and matrix micro hardness increasing gradually and reaching a peak at 750HV, respectively, which is significantly greater than the base metal (SS-316) hardness (about 220HV). The clads erosive wear was measured at various impact angles (30°, 60°, and 90°) by utilizing a solid particle erosion with alumina as the erodent. In addition, corrosion testing found that in the NaCl solution of 3.5 wt% the cladded specimen exhibited the less corrosion resistance than that of the base metal.

Planning and delivery of intensity modulated bolus electron conformal therapy.

PurposeBolus electron conformal therapy (BECT) is a clinically useful, well‐documented, and available technology. The addition of intensity modulation (IM) to BECT reduces volumes of high dose and dose spread in the planning target volume (PTV). This paper demonstrates new techniques for a process that should be suitable for planning and delivering IM‐BECT using passive radiotherapy intensity modulation for electrons (PRIME) devices.MethodsThe IM‐BECT planning and delivery process is an addition to the BECT process that includes intensity modulator design, fabrication, and quality assurance. The intensity modulator (PRIME device) is a hexagonal matrix of small island blocks (tungsten pins of varying diameter) placed inside the patient beam‐defining collimator (cutout). Its design process determines a desirable intensity‐modulated electron beam during the planning process, then determines the island block configuration to deliver that intensity distribution (segmentation). The intensity modulator is fabricated and quality assurance performed at the factory (.decimal, LLC, Sanford, FL). Clinical quality assurance consists of measuring a fluence distribution in a plane perpendicular to the beam in a water or water‐equivalent phantom. This IM‐BECT process is described and demonstrated for two sites, postmastectomy chest wall and temple. Dose plans, intensity distributions, fabricated intensity modulators, and quality assurance results are presented.ResultsIM‐BECT plans showed improved D90‐10 over BECT plans, 6.4% versus 7.3% and 8.4% versus 11.0% for the postmastectomy chest wall and temple, respectively. Their intensity modulators utilized 61 (single diameter) and 246 (five diameters) tungsten pins, respectively. Dose comparisons for clinical quality assurance showed that for doses greater than 10%, measured agreed with calculated dose within 3% or 0.3 cm distance‐to‐agreement (DTA) for 99.9% and 100% of points, respectively.ConclusionThese results demonstrated the feasibility of translating IM‐BECT to the clinic using the techniques presented for treatment planning, intensity modulator design and fabrication, and quality assurance processes.

A novel route to superhard nanocrystalline cubic boron nitride: Emulsion detonation and high-pressure high-temperature transformation-assisted consolidation

Synthesizing bulk nanocrystalline materials is challenging since grain growth should be suppressed whereas densification promoted. Here, we demonstrate a novel route to synthesize superhard bulk nanocrystalline cubic boron nitride (cBN), which combines the use of emulsion detonation and high-pressure high-temperature transformation-assisted consolidation. The emulsion detonation process activates BN to possess unique structure and chemistry, i.e. wurtzitic BN nanograins in hexagonal BN matrix with enhanced structural disordering and oxygen impurity, a combination that enhances the nucleation rate of cBN and its densification leading to the formation of bulk nanocrystalline cBN at reduced conditions. The cBN, synthesized at 7.5 GPa and 1800 °C, displayed Vickers hardness values of 50−62 GPa for 5−20 N loads. The findings in the study suggest a feasible solution to synthesize bulk nanocrystalline cBN in a more scalable way, while also providing design insights on how to refine grain growth while enhancing densification to synthesize bulk nanocrystalline materials.

Effects of jet diameter and spacing in a micromixer-like burner for clean oxy-fuel combustion in gas turbines

The effects of jet diameter and spacing on flame structure and stability are examined in an oxy-methane micromixer-like burner for potential implementation in zero-emission gas turbines. Three burner headend geometries (HE1, HE2, and HE3) are compared at fixed flame-base velocity of 5.2 m/s and over ranges of equivalence ratio and oxygen fraction (O2 vol% in the O2/CO2 oxidizer). HE1 has 61 jets of 3.175-mm diameter, arranged on a hexagonal matrix with a uniform jet spacing of 5.5 mm. HE2 has 37 jets of 3.970-mm diameter (25% increase), also arranged hexagonally with a spacing of 5.5 mm. HE2 has fewer jets to maintain almost the same combustor power. HE3 is similar to HE2, but with a jet spacing of 7.0 mm (27% increase). The three blowout limits were found to be only ∼45 K apart, despite the considerable differences in jet diameter and spacing, which demonstrates the remarkable geometry flexibility of micromixers. HE1 outperformed HE2 and HE3. Increasing the jet diameter adversely affects flame stability, because the burner deviates from the stable lean-direct-injection concept. Increasing jet spacing is also unfavorable. The adiabatic flame temperature is the primary parameter controlling the structure and stability of premixed methane flames for different burner geometries.

Investigation of the structural and photoluminescence properties of Eu3+ doped Na6CaP2O9 phosphors for solid state lighting

A series of Eu3+ doped Na6CaP2O9 phosphors were synthesized via conventional solid state reaction method and characterized through XRD, FTIR, diffused reflectance, photoluminescence excitation and emission spectra and Raman spectra. The XRD analyses confirm the successful synthesis of hexagonal structured Na6CaP2O9 matrix. The luminescent spectra reveal that the samples can be well excited under near UV light to get an efficient orange red emission. To get a deeper insight into the usefulness of the present material, the phonon sideband analysis and Judd- Ofelt analysis were also performed. The energy transfer interaction between Eu3+ ions was dipole-dipole in nature, as evident from the Dexter theory. The thermal stability analysis and quantum yield measurements were also made. The CIE coordinates of the phosphors were observed to lie in the orange–red region. The present investigation proves the Eu3+ doped Na6CaP2O9 to be a potential orange-red phosphors in near-UV based LEDs.

Fischer-Tropsch studies in a 3D-printed stainless steel microchannel microreactor coated with cobalt-based bimetallic-MCM-41 catalysts

Fischer-Tropsch (FT) synthesis was carried out using 3D-printed stainless steel (SS) microreactors, containing channels of dimensions 500 μm × 500 μm ×2.7 cm, to study the effect of Fe, Ru, and Ni on Co-MCM-41 catalyst. The mono and bimetallic cobalt-based catalysts: 15 % Co-MCM-41, 10 %Co5% Ru MCM-41, 10 %Co 5%Ni MCM-41, and 10 %Co 5%Fe MCM-41 were synthesized using one-pot hydrothermal method and characterized by SEM-EDX, TEM, TPR, FTIR, XPS, and low and wide angle XRD techniques. All the catalysts exhibited high surface area without the loss of ordered mesoporous structure as confirmed by large BET surface areas (400- 1000 m2/g) and low angle XRD data. The metal nanoparticles were in the range of 35−50 nm and well dispersed in a hexagonal matrix of MCM-41. TPR data indicate that all other metal oxides except that of cobalt can be reduced with H2 below 600 °C. Cobalt is present most likely as cobalt silicates that can only be reduced with H2 at a temperature over 650 °C. The microchannels of SS reactor were uniformly coated by dip coating a slurry of the catalyst with polyvinyl alcohol (PVA). The catalytic performance for FT synthesis was carried out in the SS microreactor at atmospheric pressure in the temperature range of 180–300 °C with H2/CO molar ratio of 3. Incorporation of the second metal in the Co-MCM-41 framework and the operating temperature had a significant effect on CO conversion and selectivity towards C1-C4 alkanes in FT synthesis. While the highest CO conversion of 74 % was obtained for CoFe-MCM-41 at 240 °C, the highest selectivity towards butane (11 %) and propane (39 %) was observed for CoRu-MCM-41 at 240 °C and CoFe-MCM-41 at 210 °C, respectively. The rate of deactivation of the catalysts -followed the order: CoRu-MCM-41> CoNi-MCM-41> Co-MCM-41> CoFe-MCM-41, indicating that CoFe-MCM-41 is the most suitable catalyst for F–T synthesis in terms of long term stability.

Formation of long-period stacking-ordered (LPSO) structures and microhardness of as-cast Mg-4.5Zn–6Y alloy

Long-period stacking-ordered (LPSO) structures formed in both the α-Mg component and the interdendritic component in as-cast Mg-4.5Zn–6Y-0.5Zr (wt.%) alloy were studied from micro to atomic scales. Inside the α-Mg component, stacking-ordered structure took three forms: single unit, scattered cluster, and a single layer of short range 18R structures. Chemical ordering of clusters of Zn and Y formed in the short range scale but not in the long range. Inside the interdendritic component LPSO-layered structure took two forms: 18R and 14H LPSO. Long-range 18R formed at locations with high concentrations of Zn and Y. 14H LPSO phase formed at the edge of any layer of 18R LPSO phase, sandwiched between 18R and α-Mg band. We concluded that the formation of LPSO had occurred in two distinct steps. First, Zn and Y atoms were segregated into two adjacent atomic layers of the original hexagonal close-packed matrix. Then, the nucleation of stacking fault occurred, followed by the growth of a stacking fault, which attracted more Zn and Y atoms into four constitutive close-packed layers, forming a new segment of an LPSO structural unit.

Advancements in the Helium-Cooled Pebble Bed Breeding Blanket for the EU DEMO: Holistic Design Approach and Lessons Learned

The helium-cooled pebble bed (HCPB) blanket is one of the two concepts proposed as a driver blanket for the European Union Demonstration Fusion Power Reactor (EU DEMO). In contrast to past conceptual design studies, in the frame of the current Power Plant Physics and Technology of the EUROfusion Consortium, the ongoing EU DEMO preconceptual design activities have adopted a holistic and integrated (i.e., systems engineering) design approach. As a consequence of this new approach, many interfaces and requirements have been identified, some of them driving the design of the blankets. This paper shows the advancements in the HCPB breeding blanket and describes the lessons learned after implementing the new approach. This new set of requirements has led us to reconsider fundamental aspects of the HCPB blanket design, especially in the way of how the heat is extracted from the blanket. Among others, the requirement to achieve a mature balance of plant (BOP) system plays a central role as a key design driver and has forced us to reduce pressure drops in the breeding blanket. In this regard, the blanket has been redesigned, leading to an enhanced concept based on single-module segments with a hexagonal matrix of fuel-breeder pins. Both the fuel-breeder pins and the first wall (FW) are equipped with turbulence promoters (augmented wall roughness in the fuel-breeder pins and V-ribs in the FW), following a similar idea as in the past MAGNOX, Advanced Gas Reactor (AGR), and Gas Cooled Reactor (GCR) programs in fission. This has led to minimizing the pressure drops while maximizing the heat transfer. Also, the blanket outlet temperature has been extended to 520°C, following the same principle as in Generation IV’s GCRs of maximizing the temperature difference across the core to minimize the reactor mass flow rate and thus the circulating power. All these features have led to a remarkably low plant circulating power (80 to 90 MW) and the required power per helium blower (5 to 6 MW), which potentially solves the key long-standing problem of the BOP technology readiness level for an ≈2.4-GW(thermal) helium-cooled DEMO reactor.

A Study on Permanent of L-R Hexagonal Fuzzy Number Matrices

In this paper, it is shown that a number of properties of permanent of both square and non-square matrices present under fuzzy environment. We establish the basic formulas of determinant and permanent of matrices which contains the new properties to compare the both notions. We investigate the permanent of square L-R hexagonal fuzzy matrix (L-R HFM) using in different ways from partial derivatives. The notions of permanent of non-square L-R hexagonal fuzzy matrix are defined. Moreover, we derive some of the standard properties and constant matrix with the aid of above notion.