Solid Water Research Articles

Three-phase equilibria of hydrates from computer simulation. III. Effect of dispersive interactions in the methane and carbon dioxide hydrates.

In this work, the effect of the range of dispersive interactions in determining the three-phase coexistence line of the CO2 and CH4 hydrates has been studied. In particular, the temperature (T3) at which solid hydrate, water, and liquid CO2/gas CH4 coexist has been determined through molecular dynamics simulations using different cutoff values (from 0.9 to 1.6nm) for dispersive interactions. The T3 of both hydrates has been determined using the direct coexistence simulation technique. Following this method, the three phases in equilibrium are put together in the same simulation box, the pressure is fixed, and simulations are performed at different temperatures T. If the hydrate melts, then T > T3. Conversely, if the hydrate grows, then T < T3. The effect of the cutoff distance on the dissociation temperature has been analyzed at three different pressures for CO2 hydrate: 100, 400, and 1000bar. Then, we have changed the guest and studied the effect of the cutoff distance on the dissociation temperature of the CH4 hydrate at 400bar. Moreover, the effect of long-range corrections for dispersive interactions has been analyzed by running simulations with homo- and inhomogeneous corrections and a cutoff value of 0.9nm. The results obtained in this work highlight that the cutoff distance for the dispersive interactions affects the stability conditions of these hydrates. This effect is enhanced when the pressure is decreased, displacing the T3 about 2-4K depending on the system and the pressure.

Green and sustainable techniques to increase the extraction of phenolic compounds from turnip greens by‐products

AbstractThe work was aimed to optimize extraction and recovery of phenolics from turnip greens by‐products using eco‐sustainable techniques based on the use of microwaves, ultrasound, or enzymes and of water as solvent. The optimization of ultrasound‐ and microwave‐assisted extractions was performed using a 4‐factors/3‐levels and a 3‐factors/3‐levels Box–Behnken Design (BBD), respectively and the results of the corresponding trials were fitted to a second order polynomial model. The enzymatic extractions were performed using three different commercial enzymatic preparations, optionally combined with an ultrasound treatment carried out according to the central values of the BBD design. The best results obtained from each green technique were compared with those of the conventional solid–liquid extraction performed with a 70% ethanol aqueous solution. Regarding ultrasounds, the conditions able to maximize the total phenolic concentrations of the extracts (solid–water ratio, 50 g/L; T, 45°C; t, 40 min; power, 24 W) increased the extraction efficiency by about 75% and reduced the extraction times from 2 h to 10 min with respect to the conventional extraction. Concerning microwaves, the optimized conditions (solid‐water ratio, 75 g/L; t, 3 min; power, 160 W) allowed the increase of the extraction efficiency by about 48% and the decrease of the extraction times to just a few minutes. For both techniques, the factor that mainly affected extraction yield and antioxidant activity were “solids‐to‐solvent ratio” and “power,” respectively. According to the results of the enzymatic treatments, the best extraction was that performed with the commercial mix of pectinlyase, polygalacturonase, pectinesterase, and arabinase, which had the same extraction efficiency of microwaves but required longer times (90 min). Furthermore, the combination with ultrasounds did not improve its performances. Extraction technique also affected the phenolic profiles in terms of number and concentration of compounds identified. In conclusion, ultrasounds and microwaves are the best treatments to maximize extraction yield (the first) and minimize extraction time (the second).Practical applicationsThis study presents an approach to the sustainable recovery of phenolics contained in vegetable by‐products that can be adapted to a variety of food waste. It also supplies an overview of the extraction technique efficiency. The industrial adoption of our findings can lead to the following advantages: reduction food waste and/or remove from it compounds that can alter the ecosystem balance; reduction of disposal cost; production of precious ingredients for functional foods/natural cosmetics/natural supplements; obtainment of a new source of income by creating a further activity that can run in parallel with the main production of the company and can serve to diversify investments; improvement of the green image of the company, especially if the energy necessary to the energy needed to power the new process is obtained from renewable sources.

Evaluation of radiation detectors for the determination of field output factors in Leksell Gamma Knife dosimetry using 3D printed phantom inserts

The Leksell Gamma Knife® Perfexion™ and Icon™ have a unique geometry, containing 192 60Co sources with collimation for field sizes of 4 mm, 8 mm, and 16 mm. 4 mm and 8 mm collimated fields lack lateral charged particle equilibrium, so accurate field output factors are essential. This study performs field output factor measurements for the microDiamond, microSilicon, and RAZOR™ Nano detectors.3D printed inserts for the spherical Solid Water® Phantom were fabricated for microDiamond detector, the microSilicon unshielded diode and the RAZOR™ Nano micro-ionisation chamber. Detectors were moved iteratively to identify the peak detector signal for each collimator, representing the effective point of measurement of the chamber.In addition, field output correction factors were calculated for each detector relative to vendor supplied Monte Carlo simulated field output factors and field output factors measured with a W2 scintillator. All field output factors where within 1.1 % for the 4 mm collimator and within 2.3 % for the 8 mm collimator.The 3D printed phantom inserts were suitable for routine measurements if the user identifies the effective point of measurement, and ensures a reproducible setup by marking the rotational alignment of the cylindrical print. Measurements with the microDiamond and microSilicon can be performed faster compared to the RAZOR™ Nano due to differences in the signal to noise ratio. All detectors are suitable for field output factor measurements for the Leksell Gamma Knife® Perfexion™ and Icon™.

Electron streaming dose measurements and calculations on a 1.5 T MR-Linac.

To evaluate the accuracy of different dosimeters and the treatment planning system (TPS) for assessing the skin dose due to the electron streaming effect (ESE) on a 1.5 T magnetic resonance (MR)-linac. Skin dose due to the ESE on an MR-linac (Unity, Elekta) was investigated using a solid water phantom rotated 45° in the x-y plane (IEC61217) and centered at the isocenter. The phantom was irradiated with 1 × 1, 3 × 3, 5 × 5, 10 × 10, and 22 × 22cm2 fields, gantry at 90°. Out-of-field doses (OFDs) deposited by electron streams generated at the entry and exit surface of the angled phantom were measured on the surface of solid water slabs placed±20.0cm from the isocenter along the x-direction. A high-resolution MOSkin™ detector served as a benchmark due to its shallower depth of measurement that matches the International Commission on Radiological Protection (ICRP) recommended depth for skin dose assessment (0.07mm). MOSkin™ doses were compared to EBT3 film, OSLDs, a diamond detector, and the TPS where the experimental setup was modeled using two separate calculation parameters settings: a 0.1cm dose grid with 0.2% statistical uncertainty (0.1cm, 0.2%) and a 0.2cm dose grid with 3.0% statistical uncertainty (0.2cm, 3.0%). OSLD, film, the 0.1cm, 0.2%, and 0.2cm, 3.0% TPS ESE doses, underestimated skin doses measured by the MOSkin™ by as much as -75.3%, -7.0%, -24.7%, and -41.9%, respectively. Film results were most similar to MOSkin™ skin dose measurements. These results show that electron streams can deposit significant doses outside the primary field and that dosimeter choice and TPS calculation settings greatly influence the reported readings. Due to the steep dose gradient of the ESE, EBT3 film remains the choice for accurate skin dose assessment in this challenging environment.

Exploring the Effect of Moisture on CO2 Diffusion and Particle Cementation in Carbonated Steel Slag

The study of the mechanisms affecting the preparation parameters of carbonated steel slag is of great significance for the development of carbon sequestration materials. In order to elucidate the mechanism of the influence of moisture on CO2 diffusion and particle cementation in steel slag, the effects of different water–solid ratios and water contents on the mechanical properties, carbonation products, and pore structure of steel slag after carbonation were investigated. The results show that increasing the water–solid ratio of steel slag can control the larger initial porosity and improve the carbon sequestration capacity of steel slag, but it will reduce the mechanical properties. The carbonation process relies on pores for CO2 diffusion and also requires a certain level of moisture for Ca2+ dissolution and diffusion. Increasing the water content enhances particle cementation and carbonation capacity in steel slag specimens; however, excessive water hinders CO2 diffusion. Reducing the water content can increase the carbonation depth but may compromise gelling and carbon sequestration ability. Therefore, achieving a balance is crucial in controlling the water content. The compressive strength of the steel slag with suitable moisture and initial porosity can reach 118.7 MPa, and 217.2 kg CO2 eq./t steel slag can be sequestered.

The impact of automatic tube current modulation related settings of a modern GE CT scanner on image quality and patient dose; details do matter.

To investigate the operation principles of the automatic tube current modulation (ATCM) of a modern GE healthcare CT scanner, and the impact of related settings on image quality and patient dose. A dedicated phantom (Mercury 4.0) was scanned using two of the most frequently used clinical scanning protocols (chest and abdomen-pelvis). The preset protocol settings were used as starting points (reference conditions). Scan direction, scan mode (helical vs. axial), total beam width, tube potential (kVp), and ATCM settings were then modified individually to understand their impact on radiation dose and image quality. Regarding the ATCM settings, the SmartmA minimum and maximum mA limits, and the noise index (NI) values were varied. As surrogates of patient dose, the CTDIvol and DLP values of each scan were used. As surrogates of image quality were used the image noise and the detectability index (d') of five different materials (air, solid water, polystyrene, iodine, and bone) embedded in the Mercury phantom calculated with the ImQuest software. The scanning direction did not have any effect on ATCM curves, unlike what has been observed in CT scanners from other manufacturers. Total beam width does matter, however, the SmartmA limit settings and kVp selection had the greatest impact on image quality and dose. It was seen that improper minimum mA limit settings practically invalidated the ATCM operation. In contrast, when full modulation was allowed without restrictions, noise standard deviation, and detectability index became much more consistent across the wide range of phantom diameters. For lower kVp settings an impressive dose reduction was observed that requires further investigation. SmartmA is a tool that if not properly used may increase the patient doses considerably. Therefore, its settings should be carefully adjusted for each preset different clinical protocol.

Zeolite prepared from high-calcium ladle furnace slag and fly ash for Pb2+ removal

The stockpiling of industrial solid waste and lead (Pb) pollution have become a worldwide problem, which can be potentially solved by using solid waste such as ladle furnace slag (LFS) and fly ash (FA) to prepare Pb adsorbents. In this paper, zeolites prepared from untreated high-calcium LFS and FA were used to remove Pb2+ by adsorption. The optimal adsorption conditions were an adsorbent dose of 1 g/L, pH 5, a contact time of 180 min, and an initial Pb2+ concentration of 300 mg/L. The zeolites prepared from high-calcium solid waste had a Pb2+ adsorption capacity of 292.8 mg/g and an adsorption efficiency of 97.6 %. Adsorption mainly occurred via the ion exchange of Pb2+ with Ca2+ and Na+, as well as the complexation of Pb2+. The pseudo-second-order kinetic model and the Langmuir model were used to analyze adsorption kinetics and isotherm data, supporting the occurrence of chemisorption and monolayer adsorption. Regeneration experiments demonstrated that the zeolite synthesized in this study exhibited good repeatability and cost-effectiveness. The zeolites derived from LFS and FA-based geopolymers removed Pb2+ from wastewater, offering new perspectives on utilizing high-calcium industrial waste and advancing geopolymer-based adsorbents for sustainable industrial solid waste management and water pollution treatment strategies.

Effect of parboiling treatment times on the physicochemical, cooking, textural, and pasting properties and amino acid, phenolic, and sugar profiles of germinated paddy rice from different rice varieties.

In this research, parboiling was carried out at different times (5 and 15min) on germinated paddy rice (GPR) from various basmati and non-basmati varieties. The results showed that as the parboiling time increased from 5 to 15min, E, ash content, total dietary fiber, mineral content, cooking time, and textural properties increased while L*, lipid content, total starch, gruel solid loss, water absorption, oil absorption, foaming capacity, sugar profile, and total phenolic and flavonoid content decreased as compared to GPR. All pasting properties of GPR increased except breakdown as the parboiling time increased from 5 to 15min. Parboiling altered the properties of GPR due to starch gelatinization. Total essential amino acid and gamma-aminobutyric acid decreased as the parboiling time (5 to 15min) increased. The germinated parboiled brown rice could create a highly nutritious alternative to regular brown rice as it offers improved texture and cooking qualities.

Study of PRESAGE® dosimeter for end-to-end 3D radiotherapy verification using an anthropomorphic phantom with bespoke dosimeter insert.

Modern radiotherapy techniques have advanced and become more sophisticated. End-to-end 3D verification of the complex radiotherapy dose distribution in an anthropomorphic phantom can ensure the accuracy of the treatment delivery. The phantoms commonly used for dosimetry are homogeneous solid water phantom which lacks the capability to measure the 3D dose distribution for heterogeneous tissues necessary for advanced radiotherapy techniques. Therefore, we developed an end-to-end 3D radiotherapy dose verification system based on MAX-HD anthropomorphic phantom (Integrated Medical Technologies Inc., Troy, New York) with bespoke intracranial insert for PRESAGE® dosimeter. In this study, several advanced radiotherapy treatment techniques of various levels of complexity; 3D-CRT, IMRT and VMAT treatment, were planned for a 20mm diameter of a spherical target in the brain region and delivered to the phantom. The dosimeters were read out using an in-house developed optical computed tomography (OCT) imaging system known as 3DmicroHD-OCT. It was found that the measured dose distribution of the PRESAGE® when compared with the measured dose distribution of EBT film and Monaco TPS has a maximum difference of less than 3% for 3D-CRT, IMRT and VMAT treatment plans. The gamma analysis results of PRESAGE® in comparison to EBT film and Monaco TPS show pass rates of more than 95% for the criteria of 3% dose difference and 3mm distance-to-agreement. This study proves the capability of PRESAGE® and bespoke MAX-HD phantom in conjunction with the 3DmicroHD-OCT system to measure 3D dose distribution for end-to-end dosimetry verification.

Cu(I) Coordination Compounds Conjugated to Au Nanorods for Future Applications in Drug Delivery: Insights in Molecular, Electronic and Cu Local Structure in Solid and Liquid Phase.

In the framework of the design, synthesis and testing of a library of copper complexes and nanostructured assemblies potentially endowed with antitumor and antiviral activity and useful for several applications, from drugs and related delivery systems to the development of biocidal nanomaterials, we present the detailed spectroscopic investigation of the molecular and electronic structure of copper-based coordination compounds and of a new conjugated system obtained by grafting Cu(I) complexes to gold nanorods. More in detail, the electronic and molecular structures of two Cu complexes and one AuNRs/Cu-complex adduct were investigated by X-ray photoelectron spectroscopy (XPS), synchrotron-induced XPS (SR-XPS) and near edge X-ray absorption spectroscopy (NEXAFS) in solid state, and the local structure around copper ion was assessed by X-ray absorption spectroscopy (XAS) both in solid state and water solution for the AuNRs/Cu-complex nanoparticles. The proposed multi-technique approach allowed to properly define the coordination geometry around the copper ion, as well as to ascertain the molecular structures of the coordination compounds, their stability and modifications upon interaction with gold nanoparticles, by comparing solid state and liquid phase data.

Analysis of High Levels of Urine Proteins as a Sign of Impaired Kidney Function in Communities Around a Nickel Mining Industry in Morosi District, Southeast Sulawesi

The study is proposed to analyse the influence of individual and environmental factors on protein urine levels as a parameter for impaired kidney function in the community around Nickel mining industry in Morosi Sub-District, Southeast Sulawesi Indonesia. This quantitative study used a cross sectional study design. The population was people in 3 villages around the nickel mining industry aged 20-59 years. The sample size was 61 people using simple random sampling technique. Independent variable was age as representation of individual factor and environmental factors including house condition, water quality, waste management and household liquid waste. Protein urine as a parameter for impaired kidney function as the dependent variable. Data was collected by questionnaire and taking urine samples. Data were analysed using the multinomial logistic regression test with a significance level of 95%. The results show that the determinant of proteinuria levels in communities around the Morosi nickel mining industry was age (p=0.038&lt;0.05), the water source quality (p=0.002&lt;0.05). Solid waste management (p=0.05) and waste water management (p-value=0.045&lt; 0.05). Meanwhile, the house condition had no effect on high proteinuria levels (p value&gt; 0.05). In conclusion, impaired kidney function in communities around the Morosi nickel mining industry due to age, poor quality of water sources and poor management of solid waste and household liquid waste.

Construction and Demolition Waste Ballast as a Pozzolanic Addition in Binary Cements: Characterization and Thermodynamic Stability

The use of raw materials from the recovery of construction waste is frequent. In this study, the waste is obtained from degraded railway ballast, made up of siliceous minerals. This material is added directly to the mixtures to replace part of the cement, forming a good quality cementitious product. The pozzolanic reaction is studied within the waste/lime system in a solid phase and water system for one year. Reaction products such as stratlingite, layered double hydroxide-type compounds, hydrated tetracalcic aluminate, and gels appear. The formation of stratlingite and gels was favored throughout the reaction. The reaction was monitored, calculating the saturation index.

Chemometric modeling of pharmaceuticals for partitioning between sludge and aqueous phase during the wastewater treatment process.

Computational techniques, such as quantitative structure-property relationships (QSPRs), can play a significant role in exploring the important chemical features essential for the degree of sorption or sludge/water partition coefficient (Kd) towards sewage sludge of wastewater treatment process to evaluate the environmental consequence and risk of pharmaceuticals. The current research work aims to construct a predictive QSPR model for the sorption of 148 diverse active pharmaceutical ingredients (APIs) in sewage sludge during wastewater treatment. For the development of the model, we employed easily computable 2D descriptors as independent variables. The model has been developed following the Organization for Economic Cooperation and Development's (OECD) guidelines. It has undergone internal and external validation using a variety of methodologies, as well as been tested for its applicability domain. A measure of hydrophobicity, i.e., MLOGP2, showed the most promising contribution in modeling the sorption coefficient of APIs. Among other parameters, the number of tertiary aromatic amines, the presence of electronegative atoms like N, O, and Cl, the size of a molecule, the number of aromatic hydroxyl groups, the presence of substituted aromatic nitrogen atoms and alkyl-substituted tertiary carbon atoms were also found to be influential for the regulation of solid water partition coefficient of APIs during the wastewater treatment process. The statistical validity tests performed on the developed partial least squares (PLS) model showed that it is statistically evident, robust, and predictive (R2Train = 0.750, Q2LOO = 0.683, Q2F1 = 0.655, Q2F2 (or R2Test) = 0.651). In addition, the predictivity of the constructed model was further inspected by using the "prediction reliability indicator" tool for 14 external APIs.

Resource Utilization of Solid Waste and Water Quality Evaluation

The rapid development of industrialization and urbanization has inevitably resulted in the generation of innumerable solid wastes and water contamination [...]

Shaped Laser Pulses for Microsecond Time-Resolved Cryo-EM: Outrunning Crystallization during Flash Melting.

Water vitrifies if cooled at rates above 3 × 105 K/s. In contrast, when the resulting amorphous ice is flash heated, crystallization occurs even at a more than 10 times higher heating rate, as we have recently shown. This may present an issue for microsecond time-resolved cryo-electron microscopy experiments, in which vitreous ice samples are briefly melted with a laser pulse because transient crystallization could potentially alter the dynamics of the embedded proteins. Here, we demonstrate how shaped microsecond laser pulses can be used to increase the heating rate and outrun crystallization. Time-resolved electron diffraction experiments reveal that the critical heating rate for amorphous solid water (ASW) is about 108 K/s. Our experiments add to the toolbox of the emerging field of microsecond time-resolved cryo-electron microscopy by demonstrating a straightforward approach for avoiding crystallization during laser melting and for achieving significantly higher heating rates, which paves the way for nanosecond time-resolved experiments.

Technical note: Radiological clinical equivalence for phantom materials in carbon ion therapy.

As carbon ion radiotherapy increases in use, there are limited phantom materials for heterogeneous or anthropomorphic phantom measurements. This work characterized the radiological clinical equivalence of several phantom materials in a therapeutic carbon ion beam. Eight materials were tested for radiological material-equivalence in a carbon ion beam. The materials were computed tomography (CT)-scanned to obtain Hounsfield unit (HU) values, then irradiated in a monoenergetic carbon ion beam to determine relative linear stopping power (RLSP). The corresponding HU and RLSP for each phantom material were compared to clinical carbon ion calibration curves. For absorbed dose comparison, ion chamber measurements were made in the center of a carbon ion spread-out Bragg peak (SOBP) in water and in the phantom material, evaluating whether the material perturbed the absorbed dose measurement beyond what was predicted by the HU-RLSP relationship. Polyethylene, solid water (Gammex and Sun Nuclear), Blue Water (Standard Imaging), and Techtron HPV had measured RLSP values that agreed within ±4.2% of RLSP values predicted by the clinical calibration curve. Measured RLSP for acrylic was 7.2% different from predicted. The agreement for balsa wood and cork varied between samples. Ion chamber measurements in the phantom materials were within 0.1% of ion chamber measurements in water for most materials (solid water, Blue Water, polyethylene, and acrylic), and within 1.9% for the rest of the materials (balsa wood, cork, and Techtron HPV). Several phantom materials (Blue Water, polyethylene, solid water [Gammex and Sun Nuclear], and Techtron HPV) are suitable for heterogeneous phantom measurements for carbon ion therapy. Low density materials should be carefully characterized due to inconsistencies between samples.

Universal 120-kV Dual-Source Ultra-High Pitch Protocol on the Photon-Counting CT System for Pediatric Abdomen of All Sizes: A Phantom Investigation Comparing With Energy-Integrating CT.

The purpose of this study is to determine if a universal 120-kV ultra-high pitch and virtual monoenergetic images (VMIs) protocol on the photon-counting computed tomography (PCCT) system can provide sufficient image quality for pediatric abdominal imaging, regardless of size, compared with protocols using a size-dependent kV and dual-source flash mode on the energy-integrating CT (EICT) system. One solid water insert and 3 iodine (2, 5, 10 mg I/mL) inserts were attached or inserted into phantoms of variable sizes, simulating the abdomens of a newborn, 5-year-old, 10-year-old, and adult-sized pediatric patients. Each phantom setting was scanned on an EICT using clinical size-specific kV dual-source protocols with a pitch of 3.0. The scans were performed with fixed scanning parameters, and the CTDI vol values of full dose were 0.30, 0.71, 1.05, and 7.40 mGy for newborn to adult size, respectively. In addition, half dose scans were acquired on EICT. Each phantom was then scanned on a PCCT (Siemens Alpha) using a universal 120-kV protocol with the same full dose and half dose as determined above on the EICT scanner. All other parameters matched to EICT settings. Virtual monoenergetic images were generated from PCCT scans between 40 and 80 keV with a 5-keV interval. Image quality metrics were compared between PCCT VMIs and EICT, including image noise (measured as standard deviation of solid water), contrast-to-noise ratio (CNR) (measured at iodine inserts with solid water as background), and noise power spectrum (measured in uniform phantom regions). Noise at a PCCT VMI of 70 keV (7.0 ± 0.6 HU for newborn, 14.7 ± 1.6 HU for adult) is comparable ( P > 0.05, t test) or significantly lower ( P < 0.05, t test) compared with EICT (7.8 ± 0.8 HU for newborn, 15.3 ± 1.5 HU for adult). Iodine CNR from PCCT VMI at 50 keV (50.8 ± 8.4 for newborn, 27.3 ± 2.8 for adult) is comparable ( P > 0.05, t test) or significantly higher ( P < 0.05, t test) to the corresponding EICT measurements (57.5 ± 6.7 for newborn, 13.8 ± 1.7 for adult). The noise power spectrum curve shape of PCCT VMI is similar to EICT, despite PCCT VMI exhibiting higher noise at low keV levels. The universal PCCT 120 kV with ultra-high pitch and postprocessed VMIs demonstrated equivalent or improved performance in noise (70 keV) and iodine CNR (50 keV) for pediatric abdominal CT, compared with size-specific kV images on the EICT.

Secondary neutron dosimetry for conformal FLASH proton therapy.

Cyclotron-based proton therapy systems utilize the highest proton energies to achieve an ultra-high dose rate (UHDR) for FLASH radiotherapy. The deep-penetrating range associated with this high energy can be modulated by inserting a uniform plate of proton-stopping material, known as a range shifter, in the beam path at the nozzle to bring the Bragg peak within the target while ensuring high proton transport efficiency for UHDR. Aluminum has been recently proposed as a range shifter material mainly due to its high compactness and its mechanical properties. A possible drawback lies in the fact that aluminum has a larger cross-sectionof producing secondary neutrons compared to conventional plastic range shifters. Accordingly, an increase in secondary neutron contamination was expected during the delivery of range-modulated FLASH proton therapy, potentially heightening neutron-induced carcinogenic risks to thepatient. We conducted neutron dosimetry using simulations and measurements to evaluate excess dose due to neutron exposure during UHDR proton irradiation with aluminum range shifters compared to plastic rangeshifters. Monte Carlo simulations in TOPAS were performed to investigate the secondary neutron production characteristics with aluminum range shifter during 225MeV single-spot proton irradiation. The computational results were validated against measurements with a pair of ionization chambers in an out-of-field region ( 30cm) and with a Proton Recoil Scintillator-Los Alamos rem meter in a far-out-of-field region (0.5-2.5m). The assessments were repeated with solid water slabs as a surrogate for the conventional range shifter material to evaluate the impact of aluminum on neutron yield. The results were compared with the International Electrotechnical Commission (IEC) standards to evaluate the clinical acceptance of the secondary neutronyield. For a range modulation up to 26cm in water, the maximum simulated and measured values of out-of-field secondary neutron dose equivalent per therapeutic dose with aluminum range shifter were found to be and , respectively, overall higher than the solid water cases (simulation: ; measurement: ). The maximum far out-of-field secondary neutron dose equivalent was found to be ( ) and ( ) for the simulations and rem meter measurements, respectively, also higher than the solid water counterparts (simulation: ( ) ; measurement: ( ) ). We conducted simulations and measurements of secondary neutron production under proton irradiation at FLASH energy with range shifters. We found that the secondary neutron yield increased when using aluminum range shifters compared to conventional materials while remaining well below the non-primary radiation limit constrained by the IECregulations.

Spontaneous Wetting Induced by Contact-Electrification at Liquid-Solid Interface.

Wettability significantly influences various surface interactions and applications at the liquid-solid interface. However, the understanding is complicated by the intricate charge exchange occurring through contact electrification (CE) during this process. The understanding of the influence of triboelectric charge on wettability remains challenging, especially due to the complexities involved in concurrently measuring contact angles and interfacial electrical signals. Here, the relationship is investigated between surface charge density and change of contact angle of dielectric films after contact with water droplets. It is observed that the charge exchange when water spared lead to a spontaneous wetting phenomenon, which is termed as the contact electrification induced wetting (CEW). Notably, these results demonstrate a linear dependence between the change of contact angle (CA) of the materials and the density of surface charge on the solid surface. Continuous CEW tests show that not only the static CA but also the dynamics of wetting are influenced by the accumulation charges at the interface. The mechanism behind CEW involves the redistribution of surface charges on a solid surface and polar water molecules within liquid. This interaction results in a decrease in interface energy, leading to a reduction in the CA. Ab initio calculations suggest that the reduction in interface energy may stem from the enhanced surface charge on the substrate, which strengthens the hydrogen bond interaction between water and the substrate. These findings have the potential to advance the understanding of CE and wetting phenomena, with applications in energy harvesting, catalysis, and droplet manipulation at liquid-solid interfaces.

Experimental study on the dam-break-induced surge impact on an inclined wall

The front faces of coastal structures are not always perpendicular to its foundation. To investigate the surge impact characteristics on an inclined wall, laboratory experiments about the dam-break-induced surge impact were conducted on downstream walls with four different inclination angles, i.e., −30°, −10°, 0°, and 10° (positive for forward inclination). Before the water tongue forms, surge water in front of the wall can be classified into the bottom solid water and the upper aerated water. Although the measured maximum water level is the largest in front of the vertical wall, it contains a large proportion of aerated water. In contrast, the −30° wall exhibits the largest proportion of solid water, which is associated with the force exerted on the wall. As the wall inclines forward, the impact pressure experiences an increase in its peak value and spatial extent, while a decrease in its duration. The maximum impact pressure and the maximum horizontal force induced by the initial impact increase from the backward to forward inclination, while the maximum horizontal force in the transition or quasi-static phase increases as the wall inclines. In addition, it is found that the calculation method for designing breaking wave loads on nonvertical walls underestimates the surge-induced maximum horizontal force. Regarding the potential sliding/overturning failure, the 10°/−30° wall presents the highest risk among the considered cases under the same incoming hydrodynamic conditions. These findings extend our understandings on the surge–structure interactions, being helpful for the safe design of relevant coastal structures.