Enhanced Energy Storage Performance through Controlled Composition and Synthesis of 3D Mixed Metal-Oxide Microspheres

Binary transition metal oxide complexes (BTMOCs) in three-dimensional (3D) layered structures show great promise as electrodes for supercapacitors (SCs) due to their diverse oxidation states, which contribute to high specific capacitance. However, the synthesis of BTMOCs with 3D structures remains challenging yet crucial for their application. In this study, we present a novel approach utilizing a single-step hydrothermal technique to fabricate flower-shaped microspheres composed of a NiCo-based complex. Each microsphere consists of nanosheets with a mesoporous structure, enhancing the specific surface area to 23.66 m2 g-1 and facilitating efficient redox reactions. When employed as the working electrode for supercapacitors, the composite exhibits remarkable specific capacitance, achieving 888.8 F g-1 at 1 A g-1. Furthermore, it demonstrates notable electrochemical stability, retaining 52.08% capacitance after 10,000 cycles, and offers a high-power density of 225 W·kg-1, along with an energy density of 25 Wh·kg-1, showcasing its potential for energy storage applications. Additionally, an aqueous asymmetric supercapacitor (ASC) was assembled using NiCo microspheres-based complex and activated carbon (AC). Remarkably, the NiCo microspheres complex/AC configuration delivers a high specific capacitance of 250 F g-1 at 1 A g-1, with a high energy density of 88 Wh kg-1, for a power density of 800 W kg-1. The ASC also exhibits excellent long-term cyclability with 69% retention over 10,000 charge-discharge cycles. Furthermore, a series of two ASC devices demonstrated the capability to power commercial blue LEDs for a duration of at least 40 s. The simplicity of the synthesis process and the exceptional performance exhibited by the developed electrode materials hold considerable promise for applications in energy storage.

Oxidatively Doped Tetrathiafulvalene-Based Metal-Organic Frameworks for High Specific Energy of Supercapatteries

Poor electrical conductivity and instability of metal-organic frameworks (MOFs) have limited their energy storage and conversion efficiency. In this work, we report the application of oxidatively doped tetrathiafulvalene (TTF)-based MOFs for high-performance electrodes in supercapatteries. Two isostructural MOFs, formulated as [M(py-TTF-py)(BPDC)]·2H₂O (M = Ni^II (1), Zn^II (2); py-TTF-py = 2,6-bis(4'-pyridyl)TTF; H₂BPDC = biphenyl-4,4'-dicarboxylic acid), are crystallographically characterized. The structural analyses show that the two MOFs possess a three-dimensional 8-fold interpenetrating diamond-like topology, which is the first example for TTF-based dual-ligand MOFs. Upon iodine treatment, MOFs 1 and 2 are converted into oxidatively doped 1-ox and 2-ox with high crystallinity. The electrical conductivity of 1-ox and 2-ox is significantly increased by six∼seven orders of magnitude. Benefiting from the unique structure and the pronounced development of electrical conductivity, the specific capacities reach 833.2 and 828.3 C g^-1 at a specific current of 1 A g^-1 for 1-ox and 2-ox, respectively. When used as a battery-type positrode to assemble a supercapattery, the AC∥1-ox and AC∥2-ox (AC = activated carbon) present an energy density of 90.3 and 83.0 Wh kg^-1 at a power density of 1.18 kW kg^-1 and great cycling stability with 82% of original capacity and 92% columbic efficiency retention after 10,000 cycles. Ex situ characterization illustrates the ligand-dominated mechanism in the charge/discharge processes. The excellent electrochemical performances of 1-ox and 2-ox are rarely reported for supercapatteries, illustrating that the construction of unique highly dense and robust structures of MOFs followed by postsynthetic oxidative doping is an effective approach to fabricate MOF-based electrode materials.

Electrochemical and Electrical Performances of High Energy Storage Polyaniline Electrode with Supercapattery Behavior

Polyaniline (PANI), due to its highly reversible electrochemistry with superior energy storage and delivery characteristics, is considered as an electrode material in batteries, capacitors, and hybrid systems. We used a facile electrochemical synthesis for the formation of the PANI electrode using galvanostatic polymerization of aniline on the graphite electrode at the current density of 2.0 mA cm^-2 from the aqueous electrolyte containing 0.25 mol dm^-3 aniline and 1.0 mol dm^-3 H₂SO₄. Electrochemical and electrical characterization suggested excellent energy storage features of the PANI electrode in a three-electrode system with specific energy up to 53 Wh kg^-1 and specific power up to 7600 W kg^-1. After 2000 successive charge/discharge cycles at 9.5 Ag^-1, the PANI electrode retained 95% of the initial capacity, with practically unaltered Coulombic efficiency of nearly 98%, providing a good base for future studies and practical applications.

Novel Supercapacitor Electrode Derived from One Dimensional Cerium Hydrogen Phosphate (1D-Ce(HPO4)2.xH2O)

In this manuscript, we are reporting for the first time one dimensional (1D) cerium hydrogen phosphate (Ce(HPO₄)₂.xH₂O) electrode material for supercapacitor application. In short, a simple hydrothermal technique was employed to prepare Ce(HPO₄)₂.xH₂O. The maximum surface area of 82 m² g^-1 was obtained from nitrogen sorption isotherm. SEM images revealed Ce(HPO₄)₂.xH₂O exhibited a nanorod-like structure along with particles and clusters. The maximum specific capacitance of 114 F g^-1 was achieved at 0.2 A g^-1 current density for Ce(HPO₄)/NF electrode material in a three-electrode configuration. Furthermore, the fabricated symmetric supercapacitor (SSC) based on Ce(HPO₄)₂.xH₂O//Ce(HPO₄)₂.xH₂O demonstrates reasonable specific energy (2.08 Wh kg^-1), moderate specific power (499.88 W kg^-1), and outstanding cyclic durability (retains 92.7% of its initial specific capacitance after 5000 GCD cycles).

Mesocarbon Microbeads Boost the Electrochemical Performances of LiFePO4 ||Li4 Ti5 O12 through Anion Intercalation

Li-ion batteries with LiFePO₄ cathode and Li₄ Ti₅ O₁₂ anode show promise for storing renewable energy. However, their low output voltage results in a low energy density. In contrast, dual-ion batteries with graphite cathode and Li₄ Ti₅ O₁₂ anode can achieve a high output voltage of >3.0 V. In this study, mesocarbon microbeads (MCMB)@LiFePO₄ ||Li₄ Ti₅ O₁₂ dual-ion batteries are developed to address these issues. In the cathode, MCMB improves the conductivity of LiFePO₄ and increases the output voltage by the intercalation of anions in the cell voltage range of 2.1-3.5 V. Moreover, the LiFePO₄ shell sustains the structural integrity of MCMB and generates in situ a cathode-electrolyte interphase (CEI) with rich LiF. Owing to these unique compositional and structural features, MCMB@LiFePO₄ ||Li₄ Ti₅ O₁₂ manifests much better electrochemical performance than LiFePO₄ ||Li₄ Ti₅ O₁₂ and MCMB||Li₄ Ti₅ O₁₂ . It sustains 89.6 % of the initial capacity after 1200 cycles at 0.2 A g^-1 and achieves a specific energy up to 128 Wh kg^-1 at 179 W kg^-1 .

Unveiling the Redox Electrochemistry of MOF-Derived fcc-NiCo@GC Polyhedron as an Advanced Electrode Material for Boosting Specific Energy of the Supercapattery

Metal organic frameworks (MOFs), which constitute a new class of porous organic-inorganic hybrid materials, have gained considerable attention in the fields of electrochemical energy storage and conversion devices owing to their open topological structures, large surface areas, tunable morphologies, and extreme redox activity. A synthesis protocol that comprises coprecipitation followed by controlled calcination processes to design a battery-type electrode is used. This electrode consists of three-dimensional (3D), ant cave-like polyhedrons of nickel-cobalt alloy on graphitic carbon (GC; NiCo@GC) nanostructures; trimesic acid is used as a potential MOF-linker. The developed NiCo@GC sample exhibits mesoporous characteristics with the maximum surface area of 94.08 m² g^-1 at 77 K. In addition, the redox activity at different sweep rates reveals the battery-type charge storage behavior of the NiCo@GC electrode; its three-electrode assembly provides 444 C g^-1 specific capacity at 2 A g^-1 with long-term capacity retention. The constructed supercapattery (SC) devices (i.e., AC//NiCo@GC) achieved capacity, specific energy, and specific power are 74.3 mAh g^-1 , 39.5 Wh kg^-1 , and 665 W kg^-1 , respectively. Owing to its reasonable electrochemical characteristics, the prepared NiCo@GC material is a promising candidate for supercapattery electrodes for portable electronic devices.

Cortical bone grinding mechanism modeling and experimental studyfor damage minimization in craniotomy

Craniotomy, as a part of neurosurgery, implies a safe opening of the skull with mechanical equipment. Grinding is a traditional machining method that can accurately and efficiently remove bone tissue. Aiming at low-damage and high-efficiency bone grinding, this study analyzed the kinematic law of a single abrasive grain during the grinding process. The theoretical model of grinding force was established based on the calculation of specific energy and friction force. The grinding test platform was set up, and the full factorial experimental design was performed to link the grinding force evolution with different processing parameters. The experimental results obtained on porcine femurs validated the model predictions where the grinding force grew with feed speed and grinding depth; it exhibited a decreasing trend with rotation speed, followed by increasing one.

A Nonlinear Elastic Model for Compressible Aluminum Alloys with Finite Element Implementation

In this paper, a three-dimensional model of nonlinear elastic material is proposed. The model is formulated in the framework of Green elasticity, which is based on the specific elastic energy potential. Equivalently, this model can be associated to the deformation theory of plasticity. The constitutive relationship, derived from the assumed specific energy, divides the material’s behavior into two stages: the first one starts with an initial almost linear stress–strain relation which, for higher strain, smoothly turns into the second stage of hardening. The proposed relation mimics the experimentally observed response of ductile metals, aluminum alloys in particular. In contrast to the classic deformation theory of plasticity or the plastic flow theory, the presented model can describe metal compressibility in both stages of behavior. The constitutive relationship is non-reversible expressing stress as a function of strain. Special attention is given to the calibration process, in which a one-dimensional analog of the three-dimensional model is used. Various options of calibration based on uniaxial stress test are extensively discussed. A finite element code is written and verified in order to validate the model. Solutions of selected problems, obtained via ABAQUS, confirm the correctness of the model and its usefulness in numerical simulations, especially for buckling.

Enhancing the Electromechanical Coupling in Soft Energy Harvesters by Using Graded Dielectric Elastomers

Soft dielectric elastomers can quickly achieve large deformations when they are subjected to electromechanical loads. They are widely used to fabricate a number of soft functional devices. However, the functions of soft devices are limited to the failure modes of soft dielectric elastomers. In this paper, we use graded dielectric elastomers to produce a soft energy harvester with a strong ability of energy harvesting. Compared to the conventional energy harvester with homogeneous dielectric films, our new energy harvester is made of graded elastomers and can increase both the specific energy from 2.70 J/g to 2.93 J/g and the maximum energy from 6.3 J/g to 8.6 J/g by just using a stiffer outer radius. By optimizing the material parameters in graded dielectric films, the soft energy harvester can reach better performance, and our results can provide guidance for designing powerful energy harvesters.

Cathode-Electrolyte Interfacial Processes in Lithium∥Sulfur Batteries under Lean Electrolyte Conditions

The implementation of a low electrolyte/sulfur (E/S) ratio is essential to achieving high specific energy for lithium∥sulfur (Li∥S) batteries. In reality, however, the lean electrolyte condition results in low achievable capacity and inferior cyclability. In this study, we probe the interfacial processes on the sulfur cathode under the lean electrolyte condition using operando electrochemical impedance spectroscopy (EIS) and a galvanostatic intermittent titration technique (GITT). The operando EIS reveals a significant and rapid increase in the charge-transfer resistance during the transition from high-order polysulfides to low-order ones at a low E/S ratio, which is induced by a kinetic bottleneck at the interphase due to Li-ion mass transfer limitation. The GITT results confirm the kinetic bottleneck by revealing a large discharge overpotential during the transition phase. We further demonstrate that improving the adsorption of dissolved high-order polysulfides, a key step in the interfacial processes, can alleviate the kinetic limitation, thus enhancing the achievable capacity under the lean electrolyte condition.

Combined Hot Air, Microwave, and Infrared Drying of Hawthorn Fruit: Effects of Ultrasonic Pretreatment on Drying Time, Energy, Qualitative, and Bioactive Compounds' Properties

The present study aimed to examine the effect of ultrasonic pretreatment and hot air, microwave–hot-air, infrared–hot air, and freeze-drying on the drying time, specific energy (SE), qualitative properties (i.e., color, shrinkage, and rehydration ratio), and bioactive compounds’ properties (i.e., antioxidant activity, phenolic, and flavonoid contents) of hawthorn fruit. Drying of hawthorn was conducted from 45 min for the ultrasonic + microwave–hot-air drying to 1280 min for the freeze-drying method. The lowest amount of SE was obtained using the ultrasonic-microwave–hot-air drying method, which was 47.57 MJ/kg. The lowest values in color changes (12.25) and shrinkage (17.21%) were recorded for the freeze-drying method, while the highest amounts for these traits were 45.57% and 66.75% in the HA drying, respectively. In general, the use of different drying methods reduces the antioxidant capacity (AC), total phenolic content (TPC), and total flavonoid content (TFC) during processing compared to fresh samples. The highest values for AC, TPC, TFC, and the rehydration ratio were 30.69%, 73.07 mg-GAE/gdw, 65.93 mg-QE/gdw, and 2.02 for the freeze-drying method, respectively.

Functionalized Carbon Nanotube and MnO2 Nanoflower Hybrid as an Electrode Material for Supercapacitor Application

Functionalized carbon nanotube (FCNT) and Manganese Oxide (MnO₂) nanoflower hybrid material was synthesized using hydrothermal technique as a promising electrode material for supercapacitor applications. The morphological investigation revealed the formation of ‘nanoflower’ like structure of MnO₂ connected with FCNT, thus paving an easy path for the conduction of electrons during the electrochemical mechanism. A significant improvement in capacitance properties was observed in the hybrid material, in which carbon nanotube acts as a conducting cylindrical path, while the major role of MnO₂ was to store the charge, acting as an electrolyte reservoir leading to an overall improved electrochemical performance. The full cell electrochemical analysis of FCNT-MnO₂ hybrid using 3 M potassium hydroxide (KOH) electrolyte indicated a specific capacitance of 359.53 F g⁻¹, specific energy of 49.93 Wh kg⁻¹ and maximum specific power of 898.84 W kg⁻¹ at 5 mV s⁻¹. The results show promise for the future of supercapacitor development based on hybrid electrode materials, where high specific energy can be achieved along with high specific power and long cycle life.

Calculation of microdosimetric spectra for protons using Geant4-DNA and a μ-randomness sampling algorithm for the nanometric structures

PURPOSE

Through introducing stochastic quantities that can be connected to the dimensions of the microscopic structures exposed to radiations, microdosimetry is concerned with the substantive specifications of radiation quality that could help gain insight into radiation effects. Utilizing the μ-randomness method and Geant4-DNA code, we calculated microdosimetry quantities for nanometric structures in a spherical body of water irradiated with protons. To gain more insight into the effects of radiation on microscopic structures and validate the code parameters, we made a comparison between our results obtained within Geant4-DNA and results from other simulations.

MATERIALS AND METHODS

We calculated microdosimetric quantities through irradiating a spherical body of water of 6 μm diameter with 0.5-100 MeV protons. Microdosimetric quantities were derived for cylinders with diameter × height values of 23 × 23, 50 × 100, and 300 × 300 Å × Å, which would resemble the typical sizes of sub-cellular organisms such as the DNA, nucleosome, and chromatin fiber. We exploited the concept of μ-randomness to introduce convex bodies of random positions and directions for calculating microdosimetric quantities. We used the Geant4-DNA Monte Carlo simulation toolkit for transporting protons and secondary particles and calculating the frequency- and dose-mean lineal and specific energies in cylindrical volumes. Specifically, for same-sized cylindrical volumes, microdosimetric parameters obtained by Nikjoo et al. using the KURBUC code were used for evaluation.

RESULTS

For the energy range investigated, the frequency-mean lineal energy, dose-mean lineal energy, frequency-mean specific energy, and dose-mean specific energy vary within [2.34,47.06] (keV/μm), [10.40,68.55] (keV/μm), [0.04,39.38] × 10⁶ cGy, and [0.16,90.29] × 10⁶ cGy, respectively. Regardless of the proton energy, our specific-energy results showed higher sensitivity to volume change, for smaller cylinder volumes rather than larger ones. Regardless of both proton energy and volume of the cylinder under study, we observed a generally better agreement between our frequency-mean, than dose-mean, specific energy results and the KURBUC results.

CONCLUSION

Using Geant4-DNA to account for the stochastic nature of energy depositions due to physical interactions between radiation and matter, we calculated microdosimetry parameters concerning proton irradiation. By employing microdosimetry concepts in conjunction with simulation results of our previous work on radiation effects on the DNA, we pinpointed and quantified correlations between microdosimetry parameters and DNA damage. As such, for a volume with comparable mass and mean chord length to the DNA, we could observe the clear correspondence of the mean lineal and specific energy results with the double-strand-break yields of protons in Gy^-1.Gbp^-1.

All-Solid-State Batteries with a Limited Lithium Metal Anode at Room Temperature using a Garnet-Based Electrolyte

Metallic lithium (Li), considered as the ultimate anode, is expected to promise high-energy rechargeable batteries. However, owing to the continuous Li consumption during the repeated Li plating/stripping cycling, excess amount of the Li metal anode is commonly utilized in lithium-metal batteries (LMBs), leading to reduced energy density and increased cost. Here, an all-solid-state lithium-metal battery (ASSLMB) based on a garnet-oxide solid electrolyte with an ultralow negative/positive electrode capacity ratio (N/P ratio) is reported. Compared with the counterpart using a liquid electrolyte at the same low N/P ratios, ASSLMBs show longer cycling life, which is attributed to the higher Coulombic efficiency maintained during cycling. The effect of the species of the interface layer on the cycling performance of ASSLMBs with low N/P ratio is also studied. Importantly, it is demonstrated that the ASSLMB using a limited Li metal anode paired with a LiFePO₄ cathode (5.9 N/P ratio) delivers a stable long-term cycling performance at room temperature. Furthermore, it is revealed that enhanced specific energies for ASSLMBs with low N/P ratios can be further achieved by the use of a high-voltage or high mass-loading cathode. This study sheds light on the practical high-energy all-solid-state batteries under the constrained condition of a limited Li metal anode.

Jet milling industrialization of sticky active pharmaceutical ingredient using quality-by-design approach

Jet milling is frequently used in pharmaceutical industry to achieve different objectives. It can be used as enabling technology to overcome poor water solubility linked to hydrophobic active of pharmaceutical ingredient (API) by reducing the particle size and therefore increasing the dissolution rate. Alternatively, jet milling can be used either to enhance blending efficiency of API with excipient in case of formulation at low dosage strength or to achieve the required particle size for inhalation therapy. In this study, development of commercial manufacturing process of sticky API and its industrialization are described. The methodology used is based on quality-by-design approach to deliver safe, effective and robust manufacturing process. The study showed that the specific energy is a key factor that drives particle size during jet milling and the scale-up from lab to industrial scale. After understanding the process, a design space was built where different zones such as operating point, operating space (where the product is compliant to specification despite variability of process parameters), and the knowledge space were outlined. Finally, an industrial installation was proposed to deliver product with high productivity yield, compliant with safety regulation, and cleanable in place.

Kirkendall Growth and Ostwald Ripening Induced Hierarchical Morphology of Ni-Co LDH/MMoS x (M = Co, Ni, and Zn) Heteronanostructures as Advanced Electrode Materials for Asymmetric Solid-State Supercapacitors

By changing the mixed metal sulfide composition, morphology tuning of an active electrode material can be possible, which can have a huge impact on its electrochemical performance. Here, effective morphology tuning of Ni-Co layered double hydroxide (LDH)/MMoS _x (M = Co, Ni, and Zn) heteronanostructures is demonstrated by varying the composition of MMoS _x. Taking advantage of the benefits associated with Kirkendall growth and Ostwald ripening, tunable morphologies were successfully achieved. Among the Ni-Co LDH/MMoS _x (M = Co, Ni, and Zn) heteronanostructures, a Ni-Co LDH/NiMoS _x core-shell structured electrode delivered a high specific capacity of 404 mAh g^-1 at 3 mA cm^-2 and an extraordinary cycling stability (after 10 000 cycles) of 93.2% at 50 mA cm^-2. In addition, an asymmetric supercapacitor (ASC) device coupled with Ni-Co LDH/NiMoS _x as the cathode and Fe₂O₃/reduced graphene oxide as the anode exhibited excellent cell capacity and extraordinary cycling stability. Moreover, the ASC device provided a very high specific energy of 72.6 Wh kg^-1 at a specific power of 522.7 W kg^-1 and maintained the specific power of 23.5 Wh kg^-1 at 5357.6 W kg^-1, demonstrating its high applicability to energy storage devices.

Force Prediction for Incremental Forming of Polymer Sheets

Incremental sheet forming (ISF) is gaining attention as a low cost prototyping and small batch production solution to obtain 3D components. In ISF, the forming force is key to define an adequate setup, avoiding damage and reducing wear, as well as to determine the energy consumption and the final shape of the part. Although there are several analytical, experimental and numerical approaches to estimate the axial forming force for metal sheets, further efforts must be done to extend the study to polymers. This work presents two procedures for predicting axial force in Single Point Incremental Forming (SPIF) of polymer sheets. Particularly, a numerical model based on the Finite Element Model (FEM), which considers a hyperelastic-plastic constitutive equation, and a simple semi-analytical model that extends the known specific energy concept used in machining. A set of experimental tests was used to validate the numerical model, and to determine the specific energy for two polymer sheets of polycarbonate (PC) and polyvinyl chloride (PVC). The approaches provide results in good agreement with additional real examples. Moreover, the numerical model is useful for accurately predicting temperature and thickness.

The mechanics of bolt drilling and theoretical analysis of drilling parameter effects on respirable dust generation

The respirable dust generated during bolt-hole drilling can present serious health problems to the miners involved in roof drilling operations. A proactive dust control approach, different from the conventional passive approaches, is proposed. Laboratory experiments have been conducted to validate the dust reduction effects of the approach. A mechanical model has been developed to simulate the rotary drag bits drilling process under different cutter conditions. The functions of the area of the total friction, drilling power, and specific energy are all presented in the model. According to this model, drilling bite depth and bit wear condition were identified as key factors influencing the respirable dust generation and energy consumption. The relationships among drilling specific energy, airborne dust concentrations of respirable and larger (1-100 μm) particles, and drilling bite depth were established. It was found that by achieving a low specific energy with a proper drilling bite depth and by avoiding worn bit use, a significant reduction of quartz-rich respirable dust from its generation source could be achieved. Once validated, the mechanical model can be used for roof bolter drilling optimization and automation control.

A Class of Organopolysulfides As Liquid Cathode Materials for High-Energy-Density Lithium Batteries

Sulfur-based cathodes are promising to enable high-energy-density lithium-sulfur batteries; however, elemental sulfur as active material faces several challenges, including undesirable volume change (∼80%) when completely reduced and high dependence on liquid electrolyte wherein an electrolyte/sulfur ratio >10 μL mg^-1 is required for high material utilization. These limit the attainable energy densities of these batteries. Herein, we introduce a new class of phenyl polysulfides C₆H₅S _xC₆H₅ (4 ≤ x ≤ 6) as liquid cathode materials synthesized in a facile and scalable route to mitigate these setbacks. These polysulfides possess sufficiently high theoretical specific capacities, specific energies, and energy densities. Spectroscopic techniques verify their chemical composition and computation shows that the volume change when reduced is about 37%. Lithium half-cell testing shows that phenyl hexasulfide (C₆H₅S₆C₆H₅) can provide a specific capacity of 650 mAh g^-1 and capacity retention of 80% through 500 cycles at 1 C rate along with superlative performance up to 10 C. Furthermore, 1302 Wh kg^-1 and 1720 Wh L^-1 are achievable at a low electrolyte/active material ratio, i.e., 3 μL mg^-1. This work adds new members to the cathode family for Li-S batteries, reduces the gap between the theoretical and practical energy densities of batteries, and provides a new direction for the development of alternative high-capacity cathode materials.

Recent Advances and Prospects of Cathode Materials for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) receive significant attention for electrochemical energy storage and conversion owing to their wide availability and the low cost of Na resources. However, SIBs face challenges of low specific energy, short cycling life, and insufficient specific power, owing to the heavy mass and large radius of Na(+) ions. As an important component of SIBs, cathode materials have a significant effect on the SIB electrochemical performance. The most recent advances and prospects of inorganic and organic cathode materials are summarized here. Among current cathode materials, layered transition-metal oxides achieve high specific energies around 600 mW h g(-1) owing to their high specific capacities of 180-220 mA h g(-1) and their moderate operating potentials of 2.7-3.2 V (vs Na(+) /Na). Porous Na3 V2 (PO4 )3 /C nanomaterials exhibit excellent cycling performance with almost 100% retention over 1000 cycles owing to their robust structural framework. Recent emerging cathode materials, such as amorphous NaFePO4 and pteridine derivatives show interesting electrochemical properties and attractive prospects for application in SIBs. Future work should focus on strategies to enhance the overall performance of cathode materials in terms of specific energy, cycling life, and rate capability with cationic doping, anionic substitution, morphology fabrication, and electrolyte matching.

Inactivation of Escherichia coli and Staphylococcus aureus by ultrasound

OBJECTIVES

The aim of this study was to obtain valuable information about the effect of ultrasonic irradiation with a frequency of 30 kHz frequency and power of 100 W on the inactivation capability of two bacterial groups, namely, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, in physiologic water samples.

METHODS

Ultrasonic irradiation of bacterial samples with different populations of 5 × 10(3), 1.5 × 10(4), and 3 × 10(4) colony-forming units/mL was performed at a constant frequency with various treatment times. The specific energy (γ) values were calculated for these different concentrations of E coli and S aureus. The rate constant for ultrasonic inactivation was estimated in the linear region of a plot representing a survival ratio logarithm versus sonication time.

RESULTS

Although a significant death rate for E coli was observed with ultrasound treatment, in contrary to expectations, an increase in S aureus populations was observed.

CONCLUSIONS

Considering the widespread use of ultrasound for sterilization of tools and equipment used in hospitals, the results obtained in this study indicate that ultrasonic irradiation is not a suitable method for the elimination of the major hospital pathogen S aureus.

Microdosimetric analysis of 211At in thyroid models for man, rat and mouse

BACKGROUND

The alpha particle emitter 211At is proposed for therapy of metastatic tumour disease. 211At is accumulated in the thyroid gland in a similar way as iodine. Dosimetric models of 211At in the thyroid are needed for radiation protection assessments for 1) patients receiving 211At-labelled pharmaceuticals where 211At may be released in vivo and 2) personnel working with 211At. Before clinical trials, preclinical studies are usually made in mice and rats. The aims of this study were to develop thyroid models for mouse, rat and man, and to compare microdosimetric properties between the models.

METHODS

A thyroid follicle model was constructed: a single layer of 6 to 10-μm thick follicle cells with centrally positioned 4 to 8 μm (diameter) spherical nuclei surrounded a 10 to 500 μm (diameter) spherical follicle lumen. Species-specific models were defined for mouse, rat and man. The source compartments for 211At were the follicle lumen, follicle cells and follicle cell nuclei. The target was the follicle cell nucleus. Simplified species-specific thyroid models were used to investigate the contribution from surrounding follicles. Monte Carlo simulations were performed using the general purpose radiation transport code MCNPX 2.6.0.

RESULTS

When 211At was homogeneously distributed within the follicle lumen, the mean specific energies per decay, 〈z〉, to the follicle cell nucleus were 2.0, 1.1 and 0.17 mGy for mouse, rat and man, respectively. Corresponding values for the single-hit mean specific energy per decay, 〈z1〉, were 1.3, 0.61 and 0.37 Gy. Assuming a homogeneous 211At concentration in the follicle lumen, <0.5%, 7%, and 45% of the emitted alpha particles were fully stopped within the follicle lumen for the respective models.

CONCLUSIONS

The results clearly show the influence of the follicle size, alpha particle range and 211At location within the thyroid follicle on the dosimetric parameters. Appropriate thyroid models are required for translation of dosimetric parameters between species.