Secondary Particles Research Articles

Simulations on the performances of neutron shielding glass materials and secondary radiation risks

Glasses with neutron shielding properties are extremely important for nuclear industries. Neutron interactions with ten different neutron shielding glass types were simulated by using GEANT4 Monte Carlo simulation toolkit. Simulation results were evaluated in terms of shielding performances, deposited energy properties and produced secondary radiation. Important evaluations were made in view of radiation safety, especially on secondary particles and radioactivity resulting from interactions between neutrons and glass samples. All simulated glass samples were found to emit risky secondary particles and radioactive nuclei after interacting with fast neutrons.

Study of secondary charged particles produced in 12C-emulsion interactions at 4.5A GeV/c

This paper deals with the interactions of [Formula: see text]C-nucleus with the nuclear emulsion at 4.5[Formula: see text]A[Formula: see text]GeV/c, focused on distributions of multiplicity and the variation of the average multiplicities for secondary charged particles (black, gray, shower, and heavy particles) for the events released from these interactions. These averages have been calculated based on a model of modified cascade evaporation. A comparison has been made between the average multiplicities of the charged secondary particles produced from [Formula: see text]C and others from projectiles that interact with the nuclear emulsion at different energies, this comparison of [Formula: see text]C with other projectiles shows the fluctuations of the values of the average shower with gray for [Formula: see text]O and [Formula: see text]Si interactions occurring somewhat faster. The average number of shower, gray particles increases with the increasing mass number of the projectile Ap, except for black particles, which are nearly constant. The correlations of the average multiplicities for the different charged secondary particles are discussed. There is strong linear dependence in the correlations of average particles of shower, compound, and heavy on gray particles. The results of experimental and theoretical data were also verified with recent analysis data and new observations and were found to be consistent. Moreover, the results indicate that the residual target nucleus may have reached a temperature and constant excitation energy at a certain value for shower particles. The excess amount of energy at higher values of shower particles may be pumped into the system, and this energy may be expended during a transition of phase in the target nucleus system. The theoretical calculation results show good agreement with experimental data.

Robust silicon/carbon composite anode materials with high tap density and excellent cycling performance for lithium-ion batteries

Achieving high density while ensuring structural stability and low volume expansion during cycling remains challenging for Si-based anode materials in lithium-ion batteries (LIBs). Herein, we introduce a novel approach to address this issue by developing high tap-density carbon-coated sub-nano-Si-embedded activated carbon (ACSC) anode materials. The resulting ACSC exhibits an ultra-high true density exceeding 0.99 g cm−3 and a Si content of 48 % (abbreviated as ACS0.48C), leading to an impressive volumetric capacity of 2182 mA h cm−3. Despite the high tap density and Si content of ACS0.48C, the ACS0.48C/artificial graphite (ACS0.48C/AG) mixture demonstrates a remarkable capacity retention rate of 97.9 % after 200 cycles at 0.5 C, with a modest volume expansion rate of 7.3 % after 50 cycles. The outstanding electrochemical performance can be attributed to the structural stability of ACS0.48C throughout cycling. The AC scaffold provides a robust mechanical framework to prevent volume expansion and agglomeration of sub-nano-sized Si particles. Furthermore, the homogeneous mixing of amorphous Si and carbon at the atomic level ensures isotropic expansion, thereby enhancing structural stability. The unique structure of ACS0.48C, combining high tap density and superior cycling performance, offers a solution to the low tap density issue in nanostructures and introduces innovative concepts for the morphology and structural design of Si/C secondary particles.

Some Characteristics of Relativistic Secondary Charged Particles Produced in 7Li Interaction with Nuclear Emulsion

Some Characteristics of Relativistic Secondary Charged Particles Produced in 7Li Interaction with Nuclear Emulsion

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Radiosensitizer-based injectable hydrogel for enhanced radio-chemotherapy of TNBC

Radionuclide therapy (RNT) stands out as a highly effective method for treating solid tumors. However, its therapeutic efficiency faces challenges due to the radioresistance of tumors, the limited penetration depth and intracellular deposition of rays in tumor tissue, which causes residue of living cancer cells. Herein, we report a novel approach by utilizing radionuclide 131I-labelled polydopamine encapsulated gold nanoparticle co-loaded with the classical anticancer drug gemcitabine within a hydrogel formed from oxidized glucan and chitosan hydrochloride, combining RNT with chemotherapy for cancer treatment. Au, as a high Z element, is able to interact with short-range β-rays to emit bremsstrahlung and secondary charged particles which in turn increase the dose deposited in tumor cells. Simultaneously, gemcitabine is able to affect cell cycle redistribution, resulting in an increase in the radiosensitive cellular component of the cycle, and gemcitabine also inhibits the repair of radioactive damage to cellular DNA, which has a radiosensitizing effect. In both in vivo and vitro experiments, the injectable hydrogel demonstrates excellent biosecurity, stability in radionuclide labeling, and capabilities for single-photon emission computed tomography (SPECT) imaging. Compared analysis with single RNT revealed that combination therapy markedly inhibits the growth of triple-negative breast cancer. This integrated therapeutic strategy establishes an efficient tumor synergistic treatment platform, offering new avenues for advancing radionuclide therapy in the clinical treatment of cancer.

Secondary neutrons in proton and light ion beam therapy: a review of current status, needs and potential solutions

The advantages of proton and light ion beam therapy compared to conventional photon radiation therapy are well-known, mainly thanks to the characteristic depth dose distribution of ions and their radio-biological effectiveness. Nevertheless, the use of ions implies different nuclear reactions that generate secondary particles, with neutrons among them. These secondary neutrons can travel far away from the treatment volume, their measurement is a challenging complex task, and their biological effects are particularly high for neutrons with energies in the MeV range. In this review, a comprehensive description of secondary neutron dosimetry in proton and light ion beam therapy is given. Many studies have been conducted on the quantification of the secondary neutron dose, most of them have been performed for proton beams, whereas for other ions like carbon, the available information is scarce. The main measurement campaigns are summarised, focusing on the type of detectors used. In line with the detectors’ advantages and limitations, measurements performed inside and outside anthropomorphic phantoms are considered. The role of Monte Carlo radiation transport simulations is discussed since many experimental detection techniques need additional simulations to provide dose estimates. A focus on the current challenges for the measurements of neutrons with energies above 20 MeV is given, as this is one of the main components of secondary neutrons produced by therapeutic ion beams. Finally, the potential clinical relevance of the available and needed secondary neutron dose data is discussed, in terms of its impact on the treatment of patients. For this, the relative biological effectiveness of neutrons and the potential risk of cancer induction re-incidence or secondary cancer due to secondary neutron doses play a key role.

Thermal conductivities and complex network properties of fractal self-assembled/self-organized texture in binary composite materials

To investigate the relationship between histological properties and thermal conductivities of binary self-assembled/self-organized fractal materials fabricated by the mixed diffusion of filler particles, the particle group distribution of the filler particles was analyzed. Unlike conventional research on particle size distribution, we performed an analysis that focuses on interactions and connectivity between particles from the perspective of the Barabasi-Albert model. In three complex network systems of β-Si3N4 (SN)/austenitic stainless steel (SUS), SN/piezoelectric polyvinylidene fluoride (PVDF), and BaTiO3 (BT)/PVDF, the size distribution of secondary particles was a power-law distribution until the particle group grew relatively large. In the SN/SUS and SN/PVDF systems, a crossover phenomenon was observed in which the order distribution exhibited a power-law in the region where the particle group area was small, and as the particle group became larger, the order distribution became exponential distribution. On the other hand, the BT/PVDF system deviated from the power law distribution as the particle group area increased but did not exhibit an exponential distribution. The characteristics of the particle group distribution of these filler particles were closely related to thermal conductivity, indicating that the connection of particle groups was important. Furthermore, the relationship between the multifractal capacitance dimension, which is strongly correlated with the distance between the particle groups, and the total number of filler particle groups suggests that the texture of these composite material systems may have both small-world and scale-free properties. We also focused on the relationship between the multifractal and complex network properties of the three particle groups. As a result, a correlation was found between the slope γ, which reflects the characteristics of the power distribution, and the thermodynamic parameter α (corresponding to internal energy change) obtained from multifractals. In particular, the smaller the change in γ relative to the change in α, the more pronounced the bonding of particles and particle groups, while the larger change in γ suggested the dispersion of particle groups.

Surface atomic arrangement of primary particles through pre-oxidation to enhance the performance of LiNi0.8Co0.1Mn0.1O2 cathode materials

The primary drawback of Ni-rich LiNixCoyMn1-x-yO2 (NCM, x ≥ 0.8) cathodes lies in their capacity and voltage fading, a phenomenon principally attributed to interfacial instability and intergranular cracks. This study introduces a simple pre-oxidation treatment to modify the grain boundary of LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material as an efficient solution to these issues. Spectroscopic analysis and atomic-level imaging affirm that this pre-oxidation treatment facilitates both the conversion of Ni2+ to Ni3+ and the formation of an ordered NiOOH structure on the surface of precursor primary particles. Consequently, the final NCM811 product displays a distinct layered structure with a reduced degree of Li/Ni disorder. Furthermore, a rock-salt phase surface reconstruction layer is in-situ induced on the surface of NCM811 primary particles during the solid-state lithiation process, providing a protective coating against further degradation of the R3¯m-layered phase beneath it. Therefore, this enhanced NCM811 demonstrates superior structural stability regarding phase transition, cathode-electrolyte interface structure, and morphological integrity. When compared to bare NCM811 and modified NCM811 based on secondary particles, this enhanced NCM811 exhibits greater reversible capacity, superior initial coulombic efficiency, and excellent capacity retention. This study thus offers a promising approach to induce the ordered surface reconstruction of primary cathode particles, forming a conformal protective layer that improves electrochemical stability.

New developments in the MCUNED-Plus code for radiation transport and coupled transport-activation computational simulations in accelerator-based facilities

The radiation hazard is one of the major aspects of concern in the design of a facility where it exists a risk of exposure to ionizing radiation. The nuclear analysis for radioprotection purposes requires an accurate description of the radiation fields. This is especially true in accelerator-based facilities where several types of particles are producing the radiation fields. Radiation fields exist during the accelerator operation, but delayed radiation may also be significant for a long time after operation ends. The radiation fields of concern present during the operation are due to the secondary neutrons and photons emitted by the interaction of accelerated particles with the accelerator components (beam leakage) or with the target. The radiation present after the operation is the residual photon field produced by activated materials, these materials being activated by both accelerated particles and secondary neutrons. This residual radiation field is relevant in high intensity accelerators like IFMIF-DONES.In order to address these complex radiation transport simulations, the D1SUNED code has been updated and the new code release renamed as MCUNED-Plus. The new developments include improvements in the light-ion transport like the implementation of a variance reduction for the production of secondary particles, and a new kinematics to reproduce the angular distribution of secondary particles emitted after deuteron breakup reaction. The calculation of the residual photon field in accelerator facility has also been improved by allowing to evaluate both light-ions and secondary neutrons induced shutdown dose rate in a single coupled simulation.

Experimental study on the design method of lost circulation materials for induced fractures

Owing to the influence of fluctuating wellbore pressure, the fracture width in formations with induced fractures changes dynamically. However, the traditional design method for fracture plugging materials is based on a static fracture width, which leads to the easy destruction of the plugging layer established underground and a high risk of secondary loss. Until now, the treatment of lost circulation in formations with induced fractures still faces significant challenges. Therefore, a dynamic fracture plugging experimental device was developed in this study to investigate the bridging–plugging process of lost circulation materials (LCMs) within induced fractures, as well as the design criteria for LCMs for induced fractures. Experimental results show that through adjusting the mass ratio and total concentration of the three-level bridging material, the plugging position of the bridging material can be changed, and the fracture reopen pressure can be increased. When the mass ratio of the three-level bridging material satisfies primary bridge particle: secondary bridge particle: tertiary bridge particle = 1:1:2 and the total concentration is greater than 5%, the plugging material compounded with the three-level bridging material is prone to retention in the induced fractures, exhibiting short bridging time, low permeability of the formed plugging layer, and high fracture initiation pressure. It can effectively prevent the opening of fractures or the generation of new induced fractures, thereby reducing the risk of secondary loss. The research results can provide a scientific theoretical basis for the loss control of induced fractures.

Serum Calcification Propensity Is Increased in Myocardial Infarction and Hints at a Pathophysiological Role Independent of Classical Cardiovascular Risk Factors.

Vascular calcification is associated with increased mortality in patients with cardiovascular disease. Secondary calciprotein particles are believed to play a causal role in the pathophysiology of vascular calcification. The maturation time (T50) of calciprotein particles provides a measure of serum calcification propensity. We compared T50 between patients with ST-segment-elevated myocardial infarction and control subjects and studied the association of T50 with cardiovascular risk factors and outcome. T50 was measured by nephelometry in 347 patients from the GIPS-III trial (Metabolic Modulation With Metformin to Reduce Heart Failure After Acute Myocardial Infarction: Glycometabolic Intervention as Adjunct to Primary Coronary Intervention in ST Elevation Myocardial Infarction: a Randomized Controlled Trial) and in 254 matched general population controls from PREVEND (Prevention of Renal and Vascular End-Stage Disease). We also assessed the association between T50 and left ventricular ejection fraction, as well as infarct size, the incidence of ischemia-driven reintervention during 5 years of follow-up, and serum nitrite as a marker of endothelial dysfunction. Patients with ST-segment-elevated myocardial infarction had a significantly lower T50 (ie, higher serum calcification propensity) compared with controls (T50: 289±63 versus 338±56 minutes; P<0.001). In patients with ST-segment-elevated myocardial infarction, lower T50 was associated with female sex, lower systolic blood pressure, lower total cholesterol, lower LDL (low-density lipoprotein) cholesterol, lower triglycerides, and higher HDL (high-density lipoprotein) cholesterol but not with circulating nitrite or nitrate. Ischemia-driven reintervention was associated with higher LDL (P=0.03) and had a significant interaction term for T50 and sex (P=0.005), indicating a correlation between ischemia-driven reintervention and T50 above the median in men and below the median in women, between 150 days and 5 years of follow-up. Serum calcification propensity is increased in patients with ST-segment-elevated myocardial infarction compared with the general population, and its contribution is more pronounced in women than in men. Its lack of/inverse association with nitrite and blood pressure confirms T50 to be orthogonal to traditional cardiovascular disease risk factors. Lower T50 was associated with a more favorable serum lipid profile, suggesting the involvement of divergent pathways of calcification stress and lipid stress in the pathophysiology of myocardial infarction.

In Situ Electrochemical Polymerization of Cathode Electrolyte Interphase Enabling High-Performance Lithium Metal Batteries.

Lithium metal batteries (LMBs) with high-voltage nickel-rich cathodes show great potential as energy storage devices due to their exceptional capacity and power density. However, the detrimental parasitic side reactions at the cathode electrolyte interface result in rapid capacity decay. Herein, a polymerizable electrolyte additive, pyrrole-1-propionic acid (PA), which can be in situ electrochemically polymerized on the cathode surface and involved in forming cathode electrolyte interphase (CEI) film during cycling is proposed. The formed CEI film prevents the formation of microcracks in LiNi0.8Co0.1Mn0.1O2 (NCM811) secondary particles and mitigates parasitic reactions. Additionally, the COO- anions of PA promote the acceleration of Li+ transport from cathode particles and increase charging rates. The Li||NCM811 batteries with PA in the electrolyte exhibit a high capacity retention of 83.83% after 200 cycles at 4.3V, and maintain 80.88% capacity after 150 cycles at 4.6V. This work provides an effective strategy for enhancing interface stability of high-voltage nickel-rich cathodes by forming stable CEI film.

Investigations on kaolin mixtures: Impact on mullite formation kinetics and microstructure evolution

AbstractThis study evaluates Algerian kaolin (Djebel Debbagh (DD1) and Tamazart (KT2)) as potential substitutes for commercial kaolin (Lab) in the production of mullite‐based ceramics. Three compositions were prepared by incorporating the appropriate percentage of alumina to each calcined kaolin to achieve stoichiometric mullite precursors. The phase evolution of individual kaolin powders, as well as their mixtures with alumina, depends strongly on the calcination temperature and kaolin impurities. The differential scanning calorimetry combined with thermogravimetric analysis (TGA) showed lower secondary mullite formation temperature for the KT2‐based mixture. However, X‐ray diffraction revealed a complete mullitization in DD1 mixture. The K2O hindered cristobalite formation and reduced secondary mullite formation rate. Microstructure analysis showed lath‐shaped primary mullite and equi‐axed secondary mullite particles. After sintering at 1600°C, The KT2‐based sample (M3) exhibited higher density (3.013 g/cm3) and hardness (9.9 GPa), whereas the DD2‐based sample (M2) showed moderate densification (2.91 g/cm3) and higher flexural strength (159.42 MPa). Impurities (mainly Fe2O3, and K2O) promoted liquid phase sintering, resulting in greater densification in M3, whereas M2 showed more homogeneous microstructure, refined grains, and lower glassy phase content, contributing to enhanced strength.

Probing Particle-Carbon/Binder Degradation Behavior in Fatigued Layered Cathode Materials through Machine Learning Aided Diffraction Tomography.

Understanding how reaction heterogeneity impacts cathode materials during Li-ion battery (LIB) electrochemical cycling is pivotal for unraveling their electrochemical performance. Yet, experimentally verifying these reactions has proven to be a challenge. To address this, we employed scanning μ-XRD computed tomography to scrutinize Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (NCM622) and Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO). By harnessing machine learning (ML) techniques, we scrutinized an extensive dataset of μ-XRD patterns, about 100,000 patterns per slice, to unveil the spatial distribution of crystalline structure and microstrain. Our experimental findings unequivocally reveal the distinct behavior of these materials. NCM622 exhibits structural degradation and lattice strain intricately linked to the size of secondary particles. Smaller particles and the surface of larger particles in contact with the carbon/binder matrix experience intensified structural fatigue after long-term cycling. Conversely, both the surface and bulk of LLNMO particles endure severe strain-induced structural degradation during high-voltage cycling, resulting in significant voltage decay and capacity fade. This work holds the potential to fine-tune the microstructure of advanced layered materials and manipulate composite electrode construction in order to enhance the performance of LIBs and beyond.

Probing Particle‐Carbon/Binder Degradation Behavior in Fatigued Layered Cathode Materials through Machine Learning Aided Diffraction Tomography

AbstractUnderstanding how reaction heterogeneity impacts cathode materials during Li‐ion battery (LIB) electrochemical cycling is pivotal for unraveling their electrochemical performance. Yet, experimentally verifying these reactions has proven to be a challenge. To address this, we employed scanning μ‐XRD computed tomography to scrutinize Ni‐rich layered LiNi0.6Co0.2Mn0.2O2 (NCM622) and Li‐rich layered Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO). By harnessing machine learning (ML) techniques, we scrutinized an extensive dataset of μ‐XRD patterns, about 100,000 patterns per slice, to unveil the spatial distribution of crystalline structure and microstrain. Our experimental findings unequivocally reveal the distinct behavior of these materials. NCM622 exhibits structural degradation and lattice strain intricately linked to the size of secondary particles. Smaller particles and the surface of larger particles in contact with the carbon/binder matrix experience intensified structural fatigue after long‐term cycling. Conversely, both the surface and bulk of LLNMO particles endure severe strain‐induced structural degradation during high‐voltage cycling, resulting in significant voltage decay and capacity fade. This work holds the potential to fine‐tune the microstructure of advanced layered materials and manipulate composite electrode construction in order to enhance the performance of LIBs and beyond.

Impact of ZnO nanoparticles on Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposites as antibacterial agents and drug loading materials

A series of Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposites were successfully synthesized using the hydrothermal method with different ZnO masses. The novelty of this study was the obtained Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposite as a good candidate as an antibacterial agent and drug delivery material. The IR spectra showed that the samples were successfully formed. The vibrations of Fe–O and Mn–O were detected at 678.94–563.21cm−1, and that of Zn–O was located at 933.55–867.97cm−1. Meanwhile, the XRD pattern showed that the samples have two crystal phases, i.e. magnetite and ZnO. The nanostructure of the samples was studied by SAXS, showing that the Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposite formed clustering particles that were structured by secondary and primary particles. The secondary particles in the samples contained about 3–4 primary particles. The magnetic properties were characterized using VSM, showing that the samples have superparamagnetic behavior. The increase in ZnO mass affected the saturation magnetization value. The highest saturation magnetization value was approximately 8.66 emu/g for the sample with the smallest ZnO mass. The samples contained Fe2+, Fe3+, and ZnO2+ ions, which created oxidative stress that damaged the DNA cells of bacteria, as seen from the results of the antibacterial activity test. In addition, it was found that the Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposite has another potential as a drug loader material. As the ZnO mass increased, the drug loading efficiency also increased up to 75%. Thus, the prepared Mn0.5Fe2.5O4@C/ZnO-DOX nanocomposites have potential as antibacterial agents and drug loading materials.

Reverse Micelles Extraction of Prolamin from Baijiu Jiuzao: Impact of Isolation Process on Protein Structure and Morphology.

Prolamins, proteins derived from plants, have extensive applications in pharmaceutics and food science. Jiuzao is a byproduct of the Baijiu brewing industry, and is a great source of prolamin. Despite its importance, knowledge regarding the extraction techniques and the properties of prolamin derived from Baijiu Jiuzao (PBJ) remains limited. Reverse micelles (RMs) extraction offers an efficient and cost-effective method for purifying proteins. In the present study, prolamin was extracted from Baijiu Jiuzao using RMs extraction and subsequently characterized in terms of its secondary structure, morphology, and particle size distribution. Our findings indicate that the purified prolamin extracted using further RMs extraction possessed higher α-helix content (+13.25%), forming a large-scale protein network, and narrower particle size distributions compared to the crude prolamin obtained by NaOH-ethanol method. This research suggests that RMs extraction has potential applications in extracting prolamin from brewing industry byproducts, offering an environmentally friendly approach to Baijiu Jiuzao recycling.

Effect of dispersing graphene oxide with different specifications in water on lubrication performance

Graphene oxide (GO) and reduced graphene oxide (rGO) are known to exhibit low friction when dispersed in water or oil, although the underlying mechanism is not yet fully understood. In this study, five GO and rGO powders were used for friction tests in water dispersion. The structure of graphene (Raman spectrometry), the bonding state of carbon (XPS analysis), and the secondary particle size (dynamic light scattering) were measured to clarify the effects of these factors on the dispersibility of GO and rGO and on the friction coefficient. The results revealed that the smaller the secondary particle size, the higher the dispersibility, and the higher the ratio of -C-O- and C-OOH coordinated to GO and rGO, the lower the friction coefficient.

Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project

The SHiP-charm project was proposed to measure the associated charm production induced by 400 GeV/c protons in a thick target, including the contribution from cascade production. An optimisation run was performed in July 2018 at CERN SPS using a hybrid setup. The high resolution of nuclear emulsions acting as vertex detector was complemented by electronic detectors for kinematic measurements and muon identification. Here we present first results on the analysis of nuclear emulsions exposed in the 2018 run, which prove the capability of reconstructing proton interaction vertices in a harsh environment, where the signal is largely dominated by secondary particles produced in hadronic and electromagnetic showers within the lead target.