Specific Packing Research Articles

Multilayer-Dense Porous Carbon Nanosheets with High Volumetric Capacitance for Supercapacitors

Two-dimensional (2D) porous carbon materials with large specific surface area (SSA) and high packing density are promising candidates for supercapacitors but still a major challenge. Herein, a simple 2D space-confined method was proposed to fabricate multilayer-dense porous carbon nanosheets (MPCN) by taking advantage of the stacking effect from rapid-drying MgAl-layered double hydroxides (MgAl-LDH). It is found that the addition of MgAl-LDH plays a vital role in improving the sample yield and packing density of porous carbon materials, in comparison to that prepared by the traditional activation strategy. The obtained MPCN-800 sample demonstrates a large SSA of 2111 m2 g–1 with a high volumetric density of ca. 0.85 g cm–3, which enables outstanding gravimetric and volumetric specific capacitance of 374 F g–1 and 318 F cm–3, respectively, at a current density of 0.5 A g–1 as the electrode for supercapacitor. Furthermore, a symmetric two-electrode device was assembled with MPCN-800 sample for evaluating its practical application. It has a high charge-storage performance of 292 F g–1 and superior rate capability in aqueous electrolyte, meanwhile exhibiting a specific capacitance of 145 F g–1 under a voltage window of 2.5 V and a maximum energy density of 31.5 Wh kg–1 at an output power of 313 W kg–1 in organic electrolytes. The present work provides a novel and promising strategy to prepare porous carbon materials with high volumetric density for high-performance supercapacitors.

Segments of military ration pack eaters: Choice preferences among groups

Best-Worst Scaling (BWS) has the potential to improve menu design by determining the most and least preferred combat ration pack (CRP) items by military personnel. However, individual differences among large groups means that a ration pack design based on the average of preferences may leave many individuals dissatisfied. This paper extends the existing literature by segmenting Australian military personnel based on the preferences for specific ration pack items. Military personnel (n = 300) provided BWS data via an online survey providing product preferences for 21 items. Participants were randomly allocated to one of four different military scenarios developed and refined by Australian Defence Force (ADF) personnel, ensuring consistency with typical operational and training exercises. The four scenarios were presented with two environment variations (hot/dry or hot/humid) and two resupply variations (daily or resupply on day four and day seven) creating four survey sub-groups. Two-step cluster analysis revealed three military segments (Snackers, Balanced eaters, and Mindful eaters) with distinct CRP item preferences across the larger military group. This study provides insights of the feasibility and usefulness of segmenting military personnel based on ration pack item preferences. This approach could streamline the process for decision makers responsible for designing and developing ration packs, and ultimately increase consumption so that personnel obtain essential nutrition to support their performance.

Estimation and balancing of multi-state differences between lithium-ion cells within a battery pack

This article develops a combined estimation and control strategy for the balancing of cell-to-cell differences within lithium-ion battery packs. Heterogeneity in state of charge, state of health, and temperature reduces both pack lifespan and real-time performance capabilities. Balancing algorithms, typically designed for specific battery models, pack sizes, and heterogeneity types, mitigate these issues by removing differences through manipulation of cell currents. This article provides a generalized approach to balancing by introducing a framework that models state heterogeneity through a linear time-varying (LTV) model. The framework facilitates the development of a state estimation and balancing algorithm based on the Kalman filter (KF) and linear quadratic regulator (LQR). This balancing strategy contains three main benefits derived from the LTV model: (1) The modeling strategy explicitly expresses heterogeneity. Using this, (2) the combined estimator and controller is applicable for a large subset of heterogeneity types and cell models. (3) The form of the LTV heterogeneity model allows for reduction in computing costs of both the estimation and control algorithms, nearly decoupling runtime from pack size. The capabilities of the novel estimation-LQR strategy are evaluated using a realistic electro-thermal pack model with charge, temperature, and electrochemical state heterogeneity. Three case studies are performed to evaluate the accuracy of the heterogeneity estimator, effectiveness of the balancing strategy, and reduction in computation runtime as compared to a baseline strategy.

Packing Fraction, Tortuosity, and Permeability of Granular‐Porous Media With Densely Packed Spheroidal Particles: Monodisperse and Polydisperse Systems

AbstractThe geometrical and topological configurations of particles have great influences on their surrounding pore tortuosity and the permeability of granular‐porous media. In this work, we develop a relaxation iteration scheme to create random dense packings of different anisotropic‐shaped spheroidal particles with monodispersity and polydispersity in sizes, which manifest the effects of particle shape, fineness, and size distribution on the random packing fraction of particles. Subsequently, we propose a direction‐guided rapidly exploring random tree (DGRRT) algorithm to probe the geometrical tortuosity of complex pore space interstitial to spheroidal particles. A non‐linear pore tortuosity prediction model that relies on the specific surface area and packing fraction of particles, is developed to suit for polydisperse and monodisperse spheroidal particle systems. We further investigate the permeability of granular‐porous media through the lattice Boltzmann method (LBM) of fluid flow. These proposed methods can accurately predict the tortuosity and permeability by comparing against available experimental, theoretical, and numerical results reported in literature. Moreover, the effects of particle packing fraction (i.e., porosity), shape, fineness, and size distribution on the pore tortuosity and permeability of granular‐porous media are evaluated. The results reveal that these microstructural configurations have important influences on the permeability and tortuosity. Our results give an intrinsic interplay between the geometrical tortuosity and permeability of monodisperse and polydisperse particle systems, which have implications for a broad range of scientific disciplines, including the properties of rocks, sandstones and soils, and the design of ultra‐high performance concrete.

“Useless Channels” in a Molecular Crystal Formed via F···F and F···π Halogen Bonds

Tris(pentafluorophenyl)phosphine molecules in a new phase pack to form hourglass-shaped one-dimensional channels, whose inner surface is occupied by only fluorine. The channels show an effective diameter of 3.80 Å at the belly and only 2.68 Å at the neck, neither being possible for the encapsulation of any solvent molecules or for the permeability of air (N2 and O2), thus demonstrating an absolute vacuum. Such “vacuum” channels in the crystals have never been reported and would be of great significance in photo- and electrophysics. In addition, the structural analysis indicated that F···F contacts and F···π interactions are mainly responsible for the specific packing in the new phase, and a σ-hole-type attraction is found in both F···F and F···π forces according to the DFT computations.

Light-activated interlayer contraction in two-dimensional perovskites for high-efficiency solar cells.

Understanding and tailoring the physical behaviour of halide perovskites under practical environments is critical for designing efficient and durable optoelectronic devices. Here, we report that continuous light illumination leads to >1% contraction in the out-of-plane direction in two-dimensional hybrid perovskites, which is reversible and strongly dependent on the specific superlattice packing. X-ray photoelectron spectroscopy measurements show that constant light illumination results in the accumulation of positive charges in the terminal iodine atoms, thereby enhancing the bonding character of inter-slab I-I interactions across the organic barrier and activating out-of-plane contraction. Correlated charge transport, structural and photovoltaic measurements confirm that the onset of the light-induced contraction is synchronized to a threefold increase in carrier mobility and conductivity, which is consistent with an increase in the electronic band dispersion predicted by first-principles calculations. Flux-dependent space-charge-limited current measurement reveals that light-induced interlayer contraction activates interlayer charge transport. The enhanced charge transport boosts the photovoltaic efficiency of two-dimensional perovskite solar cells up to 18.3% by increasing the device's fill factor and open-circuit voltage.

Crystal Engineering of Supramolecular 1,4-Benzene Bisamides by Side-Chain Modification - Towards Tuneable Anisotropic Morphologies and Surfaces.

Benzene bisamides are promising building blocks for supramolecular nano‐objects. Their functionality depends on morphology and surface properties. However, a direct link between surface properties and molecular structure itself is missing for this material class. Here, we investigate this interplay for two series of 1,4‐benzene bisamides with symmetric and asymmetric peripheral substitution. We elucidated the crystal structures, determined the nano‐object morphologies and derived the wetting behaviour of the preferentially exposed surfaces. The crystal structures were solved by combining single‐crystal and powder X‐ray diffraction, solid‐state NMR spectroscopy and computational modelling. Bulky side groups, here t‐butyl groups, serve as a structure‐directing motif into a packing pattern, which favours the formation of thin platelets. The use of slim peripheral groups on both sides, in our case linear perfluorinated, alkyl chains, self‐assemble the benzene bisamides into a second packing pattern which leads to ribbon‐like nano‐objects. For both packing types, the preferentially exposed surfaces consist of the ends of the peripheral groups. Asymmetric substitution with bulky and slim groups leads to an ordered alternating arrangement of the groups exposed to the surface. This allows the hydrophobicity of the surfaces to be gradually altered. We thus identified two leitmotifs for molecular packings of benzene bisamides providing the missing link between the molecular structure, the anisotropic morphologies and adjustable surface properties of the supramolecular nano‐objects.

Sub‐bitstream packing based lightweight tiled streaming for 6 degree of freedom immersive video

The MPEG immersive video (MIV) has been designed to remove the redundancies of multi-view videos and merge the residuals into two textures and two geometry videos; therefore, four bitstreams and video decoders are required to provide six degrees of freedom (6DoF) in virtual reality (VR) in MIV. This letter proposes a sub-bitstream packing method and realisation in tiled streaming for MIV to provide a single bitstream for legacy systems that have a single decoder without an increase in the server-side storage. The proposed method divided the input videos into tiles in the compressed-domain to accomplish two goals: (i) generate a merged bitstream using the existing four bitstreams for legacy systems and (ii) improve the quality of an immersive video by disabling the deblocking filter. For a player with one or few numbers of decoders, the extracted tile sub-streams were merged by the proposed four specific mixed-quality tiling and packing methods using a motion-constrained tile set (MCTS), while complying with the high-efficiency video coding (HEVC) standard. Experimental results demonstrated that the proposed sub-stream packing method required a single decoder and exhibited 17.40% decoding time and 0.81% bjontegaard-delta rate (BD-rate) savings on Y-PSNR saving compared to the non-tiled streaming method.

Synthesis and characterization of alkylthio-attached azobenzene-based liquid crystal polymers: Roles of the alkylthio bond and polymer chain in phase behavior and liquid crystal formation

We demonstrate for the first time that the alkylthio (or thioether) bonds in the side-chains of liquid crystal (LC) polymers considerably influence the phase-transition behavior, mesomorphic properties, and nanostructures of the LC and crystal (Cr) phases. We synthesized three alkylthio-attached azobenzene-based polymethacrylates; namely, P–OS, P–SO, and P–SS, in which alkylthio bonds were introduced at an outer (terminal) 4-position, at an inner (polymer-chain side) 4-position, and at both the outer and inner 4-positions, respectively, of the azobenzene side chains. In marked contrast to the corresponding pre-monomers and methacrylate monomers, the P–OS, P–SO, and P–SS polymers form well-defined enantiotropic LC phases. Notably, while an outer terminal alkylthio bond renders azobenzene-based polymers (P–OS and P–SS) predominantly smectogenic, a sole inner alkylthio bond renders the P–SO polymer nematogenic. In addition, the outer and inner alkylthio bonds contribute to increasing and decreasing the phase-transition temperatures, respectively. The presence of the alkylthio bonds potentially provides LC polymers with crystallizability. Furthermore, X-ray diffractometry results reveal that the P–OS, P–SO, and P–SS polymers form deeply interdigitated bilayer structures in their SmA, highly ordered, and Cr phases. The specific packing mechanism is discussed in terms of intermolecular attractive interactions involving the sulfur atoms.

Concentric Heat Integrated Distillation Column (HIDiC): a new specific packing design, characterization and pre-industrial pilot unit validation

The concept of Heat Integrated Distillation column (HIDiC) was introduced by Mah et al [1] to improve the energy efficiency of distillation processes. Firstly, a brief review of the HIDiC configurations and pilot plants is introduced. The objective of this study is to demonstrate the performance of a new packing specific for HIDiC tested in a concentric HIDiC pilot plant to prove the operability and the overall performance. First, the new specific packing and its characterization are presented. The characterization includes the hydrodynamics, the mass transfer and heat transfer performance. For the experiments on HIDiC pilot plant, several tests are performed at steady state of 90 min. One of these experiments is presented with the operating parameters (boiler heat and pressure ratio). The cyclohexane/n-heptane binary mixture is used for these experiments. The simulation results of a classical distillation column are compared to HIDiC column steady state operation. This comparison demonstrates energy savings about 40 %.

Abstract P-47: Analysis of Phosphorus Distribution in Giant Bacteriophage Capsid by Electron Energy Loss Spectroscopy

Background: We have recently developed a method to visualize the distribution of DNA in the cytoplasm of bacteria by analytical electron microscopy (EM), using the Phosphorus signal (dsDNA contains two phosphate groups per each nucleotide pair), that was detected and mapped onto the image of the cell (Danilova et al, 2020; Loiko et al, 2020). Here we applied this technique to study much smaller objects – the DNA packing inside bacteriophage heads. We studied phiEL, giant phiKZ-like bacteriophage of the Myoviridae family that infects Pseudomonas aeruginosa (Krylov et al, 2003). We have earlier demonstrated that this phage contains an ‘inner body’ inside its capsid, which is responsible for the specific DNA packing (Sokolova et al, 2014). Methods: The phage propagation was performed as described before (Sokolova et al, 2014). A 3 ul sample of purified bacteriophage phiEL was applied to the glow-discharged carbon-coated copper grid and stained with freshly prepared ammonium Molybdate 2% aquatic solution for 30 sec. Grids were loaded into Gatan cooling holder and the temperature of the specimen was kept at -180°C. EELS spectra and phosphorus elemental maps were obtained on JEOL2100 microscope, operating at 200 kV with the Gatan GIF Quantum ER spectrometer in STEM mode. Pixel size was set to 15-20 nm. STEM drift correction was applied after each 40-50 pixels. Each spectrum was obtained at a 6.0 mrad collection angle, 0.25 eV dispersion, and 132 eV energy shift. The spectra from different pixels were aligned to carbon K-edge. Results: Phosphorus mapping inside and outside the bacteriophage capsid was performed (Fig. 1). Outside the capsid, the phosphorus signal was practically absent, which corresponds to the presence of DNA only inside the capsid. The distribution of phosphorus inside the capsid was uneven: the rectangular area in the middle of the capsid contained a weak signal, while a more intense signal was detected on the periphery. This can be explained by the presence of an ‘inner body’ inside (Fig. 1C). Conclusion: Thus, our results justify the possibility of using the analytical EM technique to study the distribution of DNA by mapping Phosphorus in biological nano-objects at relatively low content of the element.

CFD-based study on structured packing geometry

A computational fluid dynamics (CFD) based investigation of structured packing geometry was performed for gas phase hydrodynamic and mass transfer performance. The computational results were validated with experimental data with a robust mass transfer methodology for the gas-phase resistance identified through pipe flow simulations. The methodology was then applied to structured packing simulations for a variety of industrially relevant geometries. The mass transfer predictions agreed to within five percent of pilot-scale experimental data for standard commercial packings. The geometry of structured packing was studied by systematically changing the specific packing area, channel inclination angle, and channel opening angle to determine the geometry which produced a high degree of mass transfer or a low pressure drop.

A cost-analysis study of using adult red cell packs and Pedi-Packs in newborn intensive care units in Southern Iran

Background and objectiveSaving blood products is an important public health issue especially in developing countries with limited financial resources. We aimed to suggest a new hypothetical model to make a change in the current blood transfusion policy in the newborn intensive care unit (NICU) to reduce wastage of blood supplies as well as the risk of exposure to multiple donors.MethodsIn this cross-sectional study, all transfused neonates (n = 70) who were admitted to NICU of Nemazee Hospital, a tertiary referral hospital in Southern Iran, were evaluated between March and June 2019. Based on the information of neonates’ transfusion during this study period and determined transfusion indices, a specific pediatric pack was suggested and the related total costs per transfusion, as well as the donor-exposure rate of the hypothetical and the current transfusion method, were compared.ResultsConsidering the mean number of transfusions per neonate: 4 and mean volume of transfused packed red cells: 20 ml per transfusion, the cost-analysis of pediatric and the adult pack was presented. Arithmetically, we proved a higher total cost per transfusion for using adult pack comparing to pediatric pack. Additionally, using a pediatric pack set leads to a 24% reduction in RBCs wastage per transfusion and a 68.13% reduction in donor-exposure rate.ConclusionsThe assignment of a dedicated pediatric pack for neonates will be able to improve the cost-effectiveness by a substantial reduction in donor-exposure rate and blood wastage. This finding should be taken into consideration to generate economic growth and make improvements in child health status.

Спільна діяльність КХВ ПАТ «АрселорМіттал Кривий Ріг» та галузевого інституту у питаннях стандартизації.

JOINT ACTIVITIES OF COKE PRODUCTION OF PJSC «ARCELORMITTAL KRYVYI RIH» AND THE INDUSTRY RESEARCH INSTITUTE IN ISSUES OF THE STANDARDIZATION © V.V. Burdiyan, N.V. Mukina (Coke Production of PJSC «ArcelorMittal Kryvyi Rih», 50095, Dnipropetrovsk region, Kryvyi Rih, Kryvorizhstal str., 1, Ukraine), N.М. Golik, A.E. Ablaeva (State Enterprise "Ukrainian State Research Coal Chemical Institute (UHIN)", 61023, Kharkov, Vesnina st., 7, Ukraine) The article provides the scientific and methodological foundations for the development of regulatory documents for the production of products of a given quality on the example of cooperation between the relevant structural units of the State Enterprise "UKHIN" and the Сoke production of PJSC "ArcelorMittal Kryvyi Rih" in accordance with the current requirements of the legislative framework of Ukraine. The definition and goals of standardization of by-product coke production has been formulated. The definition of the types of regulatory documents for coke-chemical products, which are being developed and applied in Ukraine at the present time, has been given. A list of technical standards has been presented, developed over the last two years at the request of PJSC "ArcelorMittal Kryvyi Rih" to expand the range of products, taking into account the raw material base, features of production facilities and the production process. After carrying out the necessary examinations and approvals, the draft technical standards and changes in them are tested in the regional state enterprise, which forms and ensures the implementation of state policy in the field of technical regulation. After verification, they are transferred to the Main Fund (the holder of which is the State Enterprise "Ukrmetrteststandard") for entering into the database "Technical conditions of Ukraine". The advantages of being included in this database has been shown, which, although it is voluntary, allows consumers and all interested organizations to make sure that regulatory documents are checked and taken into account that they comply with legal requirements. The article also shows the relevance of the issue of transportation and labeling of dangerous goods for each type of goods produced by the company. The procedure has been described for the classification of goods, which covers the assignment of a product to a specific hazard class, category and packing group. Keywords: standardization, regulatory document, technical committee for standardization, technical conditions, transportation, dangerous goods, safety data sheet, toxicological and hygienic passport.. Corresponding author V.V. Burdiyan, е-mail: Viktoriya.Burdiyan@arcelormittal.com

Zeolite-graphene composite adsorbents for next generation adsorption heat pumps

In this study, consolidated composite adsorbents comprising highly porous zeolite of type AQSOA-Z02 and two types of graphene nanoplatelets (GNPs), namely H25-GNPs and M25-GNPs, are developed to enhance the performance of a thermally powered adsorption heat pump. The thermophysical properties such as specific heat capacity, packing density, thermal conductivity, and porosity of the synthesized composite adsorbents are rigorously investigated. The addition of GNPs into zeolite improves the packing density as well as the thermal conductivity significantly. The highest thermal conductivity is observed for 50 wt% H25-GNPs contained composite, which is almost 127 times higher than the parent zeolite. Porous property investigation reveals that the fabricated composites are microporous, like the parent zeolite. Besides, the equilibrium adsorption uptake of water onto the composite adsorbents is measured gravimetrically at three different temperatures, 30, 50, and 70 °C. The experimental uptake data are correlated with the modified Langmuir, Sun and Chakraborty, and Universal models to describe the adsorption process mathematically. It was found that 20 wt% H25-GNPs contained composite provides almost 43% improvement of effective volumetric uptake over the parent zeolite. All the presented findings would carry significant importance for the development of an efficient and compact adsorption heat pump system. Besides, the obtained results would be very supportive for designing zeolite composite based gas separation and storage, desalination, and thermal energy storage systems.

Influence of neurovascular embolic coil primary wind diameter on aneurysm packing density and case costs

Aims Endovascular coiling is a common modality for treating intracranial aneurysms; however, recanalization occurs in approximately 1 in 5 cases, with downstream consequences of regrowth and rupture. Aneurysm packing density >24% reduces recanalization risk; packing density can be increased by inserting additional coils or by using coils with larger volumetric filling. Coil volume depends on length and primary wind diameter (PWD). This study evaluated the influence of PWD on packing density and total case costs. Materials and methods Two hypothetical scenarios and one case study were analyzed. In scenario one, the number of coils required to achieve packing density >24% in a hypothetical aneurysm was determined for 0.012″ vs. 0.010″ PWD coils. In scenario two, the total length of 0.010″ vs. 0.012″ PWD coils required to achieve a packing density >24% was analyzed relative to aneurysm volume. In the case study, packing densities with one 0.012″ PWD coil (actual scenario) and one 0.010″ PWD coil (theoretical scenario) were compared. Results In scenario one, cost savings would be realized by using four 0.012″ PWD coils vs. seven 0.010″ PWD coils to achieve packing density >24%. In scenario two, greater volumetric filling of 0.012″ vs. 0.010″ PWD coils was correlated with lower total length of coil required. In the case study, a 0.012″ PWD coil achieved packing density >24%, whereas an equivalent length 0.010″ PWD coil would not. Limitations Theoretical modeling was used to explore the impact of coil PWD on aneurysm packing density. In clinical practice, packing density depends not only on PWD but on its length, shape, distribution within an aneurysm, and other recanalization risk factors. Conclusions Coil PWD influences packing density, the number of coils required to achieve a specific packing density, and total case costs. Using 0.012″ PWD coils may provide cost and procedural efficiencies.

Automated Identification of Molecular Crystals' Packing Motifs.

Packing motifs-patterns in how molecules orient relative to one another in a crystal structure-are an important concept in many subdisciplines of materials science because of correlations observed between specific packing motifs and properties of interest. That said, packing motif data sets have remained small and noisy due to intensive manual labeling processes and insufficient labeling schemes. The most prominent labeling algorithms calculate relative interplanar angles of nearest neighbor molecules to determine the packing motif of a molecular crystal, but this simple approach can fail when neighbors are naively sampled isotropically around the crystal structure. To remedy this issue, we propose an optimization algorithm, which rotates the molecular crystal structure to find representative molecules that inform the packing motif. We package this algorithm into an automated framework-Autopack-which both optimally rotates the crystal structure and labels the packing motif based on the appropriate neighboring molecules. In this work, we detail the Autopack framework and its performance, which shows improvements compared to previous state-of-the-art labeling methods, providing the first quantitative point of comparison for packing motif labeling algorithms. Furthermore, using Autopack (available at https://ipo.llnl.gov/technologies/software/autopack), we perform the first large-scale study of potential relationships between chemicals' compositions and packing motifs, which shows that these relationships are more complex than previously hypothesized from studies that used only tens of polycyclic aromatic hydrocarbon molecules. Autopack's capabilities help pose next steps for crystal engineering research focusing not only on a molecule's adoption of a specific packing motif but also on new structure-property relationships.

On crashing behaviors of bio-inspired hybrid multi-cell Al/CFRP hierarchical tube under quasi-static loading: An experimental study

Bio-inspired structures have gained more and more concerns attributed to their unique enhancement in energy absorption capacity. This paper experimentally investigates the axial crushing behavior and energy absorption of a second-order hybrid multi-cell aluminum and CFRP (Al/CFRP) hierarchical tube under quasi-static loading. Five different configurations of the hierarchical tubes packing CFRP hollow tubes were designed. The quasi-static compression test was employed to investigate their crushing characteristics, axial collapse and energy absorption behaviors, and further compared with the Al hollow counterparts. The effects of different configurations involving the radial topology, the sub-tube number, the wall thickness, and the packing configuration were discussed in detail. The results reveal that the multi-cell tubes undergo a specific progressive folding collapse, and the energy absorption capability can be significantly improved for the hierarchical sections. The radial topology hardly affects the crashworthiness with the constant outer-tubular diameter and thickness. Additionally, both packing number and wall thickness conduce to improving the load-bearing capacities. By comparison with the specific multi-cell tube packing Al/CFRP sub-tubes, the hybrid tube packing net CFRP tubes own better crashworthiness and conduce to a wider range of applications in the design of automobile frames and energy absorbers.

Flowability characteristics of dry supplementary cementitious materials using Carr measurements and their effect on the rheology of suspensions

Particle-size distribution, fineness, and morphology of powders used in flowable concrete greatly affect their rheological properties. An experimental investigation was undertaken to determine the physical characteristics of dry cementitious binders using Carr measurements and evaluate their coupled effects on rheology of cement-based suspensions. Cement, glass pozzolans, limestone filler, fly ashF, and ground granulated blast-furnace slag were investigated. The angles of repose, fall, and spatula, compressibility, and cohesion were measured. The experimental results showed that dry flowability of blended systems are correlated to their particle-size distribution, Blaine specific surface area, morphological characteristics, packing density, specific gravity, and cohesion. The mean average diameter, fineness, and morphological properties showed the most significant effects on dry flowability of the investigated dry powders. On the other hand, the yield stress and plastic viscosity values of the suspensions were found in good agreements with the Carr's angles and dispersion indicators of the investigated systems.

2D porous carbon nanosheet from sulfonated pitch-based graphene quantum dots for high volumetric performance EDLCs

With the ever-growing demand of miniaturized electric double-layer capacitors (EDLCs), it is still a big challenge to well-balance the competing relationships between high specific surface area (SSA) and high packing density in porous carbons. Herein, 2D porous carbon nanosheet (PCN) with high carbon yield is synthesized by a simple interface self-assembly and subsequent activation strategy from industrial sulfonated pitch by-product, which is composed of graphene quantum dots. It is bestowed with ultrathin thickness of 20 nm, adequate SSA of 2429 m2 g−1, high packing density of 0.562 g cm−3, high e-conductivity of 89 S m−1 and high mechanical flexibility all in one, giving full play to the synergistic effect of electrons and ions. Based on the structure advantages, this PCN can be used as high-performance EDLC electrode. In pure EMIMBF4 electrolyte, it achieves high volumetric capacitances of 90.1 F cm−3 at 0.5 A g−1, excellent rate capability C20/0.05 of 71% and good high-voltage endurance lifetime of 88% after 5000 cycles at 1 A g−1. Satisfactorily, the maximum volumetric energy density can come up to 39 Wh L−1. More significantly, this work can also provide a new perspective on the architectural conception of other 2D carbon materials.