Low Kinetic Energy Research Articles

A double-strand-break model for the relative biological effectiveness of electrons based on ionization clustering.

The effectiveness of ionizing radiation regarding DNA damage induction depends on its spatial energy deposition pattern. For electrons an increased effectiveness is observed at low kinetic energies due to the enhanced density of energy deposition events at electron track ends. A model is presented, which enables the calculation of the double-strand-break (DSB) yield and the relative biological effectiveness (RBE) for DSB induction of electrons. The model applies the mean free path between two ionizations and the assumption that two ionizations within a certain threshold distance are necessary to potentially lead to a DSB. Next to an expression for the electron RBE according to its common definition, a local RBE is determined, which describes the electrons' local effectiveness at a defined point on their track. This local RBE allows a better understanding of microscopic processes resulting from radiation and can be used, for instance, to describe the mean effectiveness of the mixed electron radiation field as a function of the radial distance to the center of an ion track. The presented model reflects the experimentally observed increased effectiveness of low-energetic electrons. It will be used in a future work to improve RBE predictions for ions performed with the local effect model.

Experimental Study of Soft Ballistic Packages with Embroidered Structures Fabricated by Using the Tailored Fiber Placement Technique.

Textile ballistic shields are the basis of protection against bullets and fragments with low kinetic energy. They are usually made of para-aramid fabrics or unidirectional structure (UD) sheets of ultra-high molecular weight polyethylene (UHMWPE). The aim of the research presented in the article was to obtain ballistic packages made of embroidered structures and to compare their ballistic properties with those of woven structures in terms of deformation of the standardized ballistic substrate after impact with a 9 mm bullet at a velocity of 380 ± 3 m/s. Using the tailored fiber placement method, embroidered structures were fabricated by embroidering two sets of para-aramid threads at an angle of 90°. As the woven structures, the use of para-aramid fabric made of the same yarn and with a surface weight comparable to that of embroidered structures was adopted. Ballistic packages consisted of 26 layers in five variants, also taking into account the hybrid arrangement of woven and embroidered layers. Ballistic tests have shown that the best ballistic properties have hybrid packages made by folding 13 woven and then 13 embroidered layers, where the maximum deformation of the plasticine substrate is below 23 mm. The conducted research confirmed that embroidered structures in appropriate combination with woven structures can significantly improve the ballistic properties of textile packages.

Finite element modeling and simulating pilling of polyester fabric

PurposeThe paper aims to build a finite element simulation model for pilling of polyester hairiness on the fabric to study the effects of hairiness performance on pilling and reveal pilling mechanisms.Design/methodology/approachThe finite element simulation model of pilling of polyester hairiness was established by ABAQUS. Polyester hairiness was treated as elastic thin rod, which was divided by two-node linear three-dimensional truss element. The effects of hairiness elastic modulus, hairiness friction coefficient and hairiness diameter on frictional dissipation energy, strain energy and kinetic energy produced by pilling have been studied. The analysis solution values were compared with the finite element simulation results, which was used to verify finite element simulation.FindingsThe paper provides new insights about how to reveal pilling mechanisms of polyester hairiness with different performance. Comparing finite element simulation results with analysis solutions shows that the fitness is greater than 0.96, which verifies finite element simulation. Larger hairiness elastic modulus gives rise to higher friction dissipation energy and strain energy of hairiness but lower kinetic energy. Increasing friction coefficient enhances friction dissipation and strain energy of hairiness. However, kinetic energy decreases with the increase of friction coefficient. Hairiness diameter also has an important effect on hairiness entanglement and pilling. Increasing hairiness diameter can decrease friction dissipation energy but enhance strain energy and kinetic energy.Research limitations/implicationsFinite element simulation was verified by analysis solutions. The solutions include friction dissipation energy, strain energy and kinetic energy, which cannot measured b experiment. Therefore, researchers are encouraged to simulate pilling to obtain pilling grades, which be compared with experiment results.Originality/valuePilling of polyester hairiness was simulated by ABAQUS. This method makes pilling process visualization, and pilling mechanisms was revealed from non-linear dynamics.

Experimental effective attenuation length on solids for electron kinetic energies between 1 and 14 KeV: Determination of a simple practical equation

The effective attenuation length is a fundamental parameter for the correct evaluation of XPS and AES spectra. For electron kinetic energies below 2 KeV, a large database with experimental EALs for most organic and inorganic compounds exists. In addition, several predictive equations valid in the low electron kinetic energy range are available. However, for HAXPES applications in which electron kinetic energies up to 14 KeV are used, the lack of experimental EAL data and predictive equations difficult the spectra analysis and quantification. In this work, we obtain experimental EAL values in the kinetic energy range between 1 and 14 KeV for Cu, Au, Ti, Si, Ge, TiN, SiO2, HfO2, Fe3O4, SrTiO3 and La0.7Sr0.3MnO3. The validity of the predictive equations developed for soft X-ray XPS are evaluated for high electron kinetic energies using the obtained experimental data. We find that the λfit formulae developed by Jablonski and Tougaard reproduces the experimental EAL data up to electron kinetic energies of 14 KeV within the experimental errors. Based on a fitting to the obtained experimental data for all materials used in this work we propose a simple practical equation for the evaluation of EAL for solids in the kinetic energy range between 1 and 14 KeV. The proposed equation, in comparison with the λfit predictive formulae, is only dependent on the compound effective atomic number eliminating tedious calculations based on electron inelastic mean free paths and transport mean free paths. The accuracy of the proposed practical equation reproduces within the experimental errors the experimental EALs presented in this work and the data available in the literature.

Photoelectron Imaging Study of the Diplatinum Iodide Dianions [Pt2I6]2- and [Pt2I8]2.

Photoelectron spectroscopy has been used to study the electronic structure, photodetachment, and photodissociation of the stable diplatinum iodide dianions [Pt2I6]2– and [Pt2I8]2–. Photoelectron spectra over a range of photon energies show the characteristic absence of low kinetic energy photoelectrons expected for dianions as a result of the repulsive Coulomb barrier (RCB). Vertical detachment energies of ∼1.6 and ∼1.9 eV and minimum RCBs of ∼1.2 and ∼1.3 eV are reported for [Pt2I6]2– and [Pt2I8]2–, respectively. Both of the diplatinum halides exhibit three direct detachment channels with distinct anisotropies, analogous to the previously reported spectra for PtI2– and PtI–, suggesting a platinum-centered molecular core that dominates the photodetachment. Additionally, evidence for two-photon photodissociation and subsequent photodetachment channels producing I– are observed for both dianions. Finally, an unexplained feature is observed at photon energies around 3 eV, whose origin is considered. Our work highlights the complex electronic structure of the heavy platinum-halide dianions that are characterized by a dense manifold of electronic states.

Dissociative Ionization and Coulomb Explosion of CHBrCl2 in Intense Near-Infrared Femtosecond Laser Fields

We experimentally demonstrate the dissociative photoionization of CHBrCl2 molecules in a femtosecond laser field by time-of-flight mass spectrum and dc-slice imaging technology. The results suggest that the low kinetic energy components are from the dissociative ionization process of single-charged molecular ions. The angular distribution of fragment Cl+ ions can be attributed to the features of dissociative state and molecular configuration, and that of Br+ ions results from the electronic wave-packet evolution and combination of the multi-dissociation processes. The high kinetic energy components are from the Coulomb explosion of multi-charged molecular ions, and the error of the C-Br distance involved in the Coulomb explosion can be explained by the movement of the effective charge center of the polyatomic molecule.

Evaluation of Steel and Tungsten Carbide Cobalt (WC 8Co) 5.56 x 45 mm Caliber Projectile Penetration into Silicon Carbide (SiC) Experiment and Numerical Simulation

This study aims to evaluate WC-8Co as a substitution material in a standard steel core projectile commercially produced by PT Pindad (Persero). The enhanced performance of 5.56 x 45-millimeter ammunition after the addition of WC-8Co hard metal was evaluated in terms of penetration into a silicon carbide (SiC) target. Numerical simulations and analysis of the ballistic impact of WC-8Co on ceramic targets were verified by experimental data. The results show that front core substitution in SS109 bullets from steel (Pindad standard) to WC-8Co resulted in 1.5 times greater DoP. Although projectiles with steel (Pindad standard) as the front core have a muzzle velocity higher than those using WC-8Co, they have a lower kinetic energy than the latter. In addition, WC-8Co cemented carbides also displayed higher crater and residual velocity on SiC targets; around 1.8 and 1.3 times higher, respectively. These findings demonstrate the potential use of WC-8Co for development as front core material to improve the penetration of projectiles into ceramic armour.

Feasibility study of novel DME fuel injection Equipment: Part 1- fuel injection strategies and spray characteristics

The Methanol Economy is projected as a sustainable solution to the impending global energy crisis. Methanol and Dimethyl Ether (DME) are projected as exceptional alternative fuel solutions to power future mobility, ensuring the continued growth of internal combustion engines (ICEs) in an environmentally sustainable manner. In this study, the technical feasibility of DME as an alternative to diesel is assessed using a three-dimensional computational fluid dynamics (3D-CFD) simulation approach. A novel fuel injection equipment (FIE) is computationally assessed for DME induction into the engine. A water-cooled, naturally-aspirated, compression ignition (CI) engine used for off-highway application is simulated for using DME as a complete replacement of mineral diesel. First, the baseline diesel combustion calibration is done to validate the simulation model using experimental data. For this, a 3D CFD closed-cycle model of a detailed chemistry-based solver is used. Spray characteristics revealed that DME exhibited faster evaporation than diesel, resulting in lesser fuel-rich pockets in the combustion chamber. DME fueled engine is anticipated to be more thermally efficient due to DME combustion’s lower turbulence kinetic energy, which reduces gas side heat transfer through the cylinder walls. DME’s higher total in-cylinder mass results in a lower swirl momentum and a reduced swirl ratio for the DME. The proposed FIE promotes a superior Mean Effective Injection Pressure (MEIP) and ameliorated spray penetration characteristics. This study provides systematic guidelines for selecting an appropriate FIE for DME, with Nozzle Through Flow (NTF) and MEIP tuned to achieve the best possible spray characteristics to develop an efficient and clean combustion system for the given application.

Genesis of Antibiotic Resistance (AR) LXXVII: Turbulence Modeling of Hemodynamics in Simplified Severe Sepsis Protocol‐2 (SSSP‐2)‐NCT01663701: Fluid Volume Dependent Velocity Profile Spur Adverse Pressure Gradient(APG) in BLS.

The objective is to identify the cause of the hemodynamic aberrance in the usual care group with 5 patients leading to 100% ihm; vs the sepsis protocol cohort with 11 patients @ 90.05% ihm with a median hospital stay of 5 days (pre‐ad to ER as, 0 hr. till 120 hrs. (5 days) ± 48 hrs. with a max.7 days). GCS 3‐8 (Ref: Fig 3. NCT01663701(PMID: 28973227). Neurology (Monitoring parameters): EI: (None): VI: Intubated‐IT; MI: M:1 (None). Geometry: PMN 8‐15μm, eosinophils ~15 μm, basophils ~12‐15 μm, monocytes ~14‐25 μm, lymphocytes~8‐15 μm, platelets ~2‐3 μm, RBC ~ 7.7 ± 0.7 μm; capillaries (med. size) internal diameter 6 μm, wall thickness, 1 μm, length ~0.1cm, ~blood viscosity 0.03 cm/s (human) (p48, 63: ISBN 9780128024089). Flow Regimes: Re < 2100 ÜLaminar; 2100 < Re < 4200 ÜTransition; 4200 < ReÜTurbulent (Table 1.3 p22). Approximation of Flow Regimes: 0 < Re < 1 Ü highly viscous laminar creeping motion; 1 < Re < 100 Ü Laminar strong Re dependence; 100 < Re < 103Ü Laminar, (boundary layer theory‐separation‐APG!); 103< Re < 104 Ü Transition to turbulence; 104 < Re < 106Ü Turbulent, moderate Re dependence; 106 < Re < ∞ Ü Turbulent, slight Re dependence (Table 1.2, p21). Blood Vessels(Canine): Systemic arterioles, mean diameter (mm): 0.050, number of vessels 2.8X106, mean length(mm) 1.2, total cross section cm2): 55, total volume of blood (ml) 7; capillaries: mean diameter (mm) 0.008, number of vessels, 2.7X109, mean length (mm) 0.65, total cross section (cm2) 1357.0, total volume of blood (ml) 88, total percentage of total blood vol: 5 ml; Pulmonary arterioles, mean diameter (mm): 0.100, number of vessels 1.5X108, mean length(mm) 0.7, total cross section cm2: 120, total volume of blood (ml) 8; capillaries: mean diameter (mm) 0.008, number of vessels, 2.7X109, mean length (mm) 0.5, total cross section (cm2) 1357.0, total vol of blood (ml) 68, total % of total blood vol: 4 ml; (Table 3.1p85, ISBN: 9781439845165; Ref Table 2.1 p 63 ISBN 9780128024089). Gov.Eq: Eq 2.1 to Eq 2.6 (p73). Derivation: ERP induced in the flow against an APG, the fluid particles near and within the boundary layer due to their low kinetic energy flow in the opposite direction, cannot surmount the APG, thus eddies are formed. Because of local flow reversal zone, which curtails the pressure in the fluid, and pressure in the flow separation the region is low, causing low pressure, flow deceleration(upstream) with drag force (form drag) fluid profile entering branching of mother blood vessels to daughter vessels thrusting toward the inner wall (δP/δx >0; Fig 2.10, p73) resulting flow separation at BL and yield APG (Fig 2.10, refer flow separation regions); While Fig 2.11 presents the effect of APG on velocity profile for parabolic shape: δP/δx< 0; transition: δP/δx ̴ 0; flow separation (region) at δP/δx >0, forming recirculation zone where vortex shedding and eddie formation occur (Fig 2.11, panel c. p73 ISBN 9780128024089). Prospect: Taken together, plausibly aforesaid fluid flow pattern in metarteriole of limbic system (& arborvitae – cerebellar), provided a microsphere of incubator (anaerobic‐aerobic) for ClPr, consequent toxemia/toxic shock ÜCCP ÜCEP.

Maternal cardiovascular potential and kinetic energy indices in pre-eclamptic and small-for-gestational-age pregnancies.

Non-invasive assessment of maternal cardiovascular potential and kinetic energy can be used to derive potential-to-kinetic-energy ratio (PKR) and Smith-Madigan inotropic index (SMII), which reflect the balance between blood pressure and blood flow. The aim of this study was to evaluate PKR and SMII in pregnancies complicated by hypertensive disorders of pregnancy (HDP) and/or small-for-gestational-age (SGA) birth. This was a prospective study that enrolled women with a singleton pregnancy between 5 and 41 weeks' gestation. Women who developed HDP and/or SGA underwent cardiovascular profiling from 20 weeks. To establish reference ranges for PKR and SMII, women without any pre-existing medical problems at the time of booking who did not develop HDP, SGA or other complications during pregnancy were also recruited for cardiovascular profiling. Measurements of cardiovascular parameters were obtained using a non-imaging ultrasound cardiac output monitor. A total of 688 women completed the study, including 626 controls, 21 cases with HDP, 19 cases with SGA and 22 cases with HDP and SGA. PKR was significantly elevated in pregnancies with placental dysfunction compared with controls (HDP only, 29.81 ± 9.5; HDP and SGA, 44.33 ± 24.27; SGA only, 31.05 ± 13.14; vs controls, 22.30 ± 7.93; all P < 0.05). SMII values were significantly lower only in cases affected by SGA alone when compared with controls (1.47 ± 0.23 W/m2 vs 1.75 ± 0.40 W/m2 ; P < 0.005). These differences remained statistically significant when the analysis was undertaken using multiples of the median values corrected for gestational age. The findings of this study suggest that point-of-care non-invasive cardiovascular profiling using PKR and SMII may help distinguish between pregnancies affected by specific placental disorders and those exhibiting healthy cardiovascular adaptation to pregnancy. Women with HDP and/or SGA appear to have distinctive PKR and SMII profiles that reflect low kinetic energy in pregnancies with SGA and high potential energy in pregnancies affected by HDP. Finally, non-invasive assessment of potential and kinetic cardiovascular energy demonstrates physiological high-flow and low-resistance adaptation in uncomplicated pregnancies. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Early stage growth of amorphous thin film: Average kinetics, nanoscale dynamics, and pressure dependence

We used the coherent grazing incidence small angle x-ray scattering technique to study the average kinetics and nanoscale dynamics during early-stage a-${\mathrm{WSi}}_{2}$ sputter deposition. The kinetic and dynamic properties are examined as a function of pressure, which is known to be a critical factor in determining final surface roughness. Surface growth kinetics and dynamics are characterized by time parameters extracted from the height-height structure factor and correlation functions. The roughness at a given length scale reaches a maximum before relaxing down to a steady state. The lateral length scale dependence and pressure dependence are then compared among the measured kinetics and dynamics time parameters. Surfaces grown at lower pressures are smoother, leading to longer correlation times. The time parameters to reach a dynamic steady state and a kinetic steady state show contrasting pressure dependence. A dynamic steady state is reached earlier than the kinetic steady state at high pressure. A more random deposition direction and lower kinetic energy at higher pressures can explain these phenomena, along with the hypothesis that larger nanoclusters form in vapor before arriving at the surface. A continuum model is applied to simulate the overall behavior with mixed success.

Evaluation of Volitional Swimming Behavior of Schizothorax prenanti Using an Open-Channel Flume with Spatially Heterogeneous Turbulent Flow.

Simple SummaryA lack of information on fish volitional swimming behavior in response to various instream flow conditions may inhibit the development of an effective fishway. In this study, Schizothorax prenanti, Tchang, 1930 (S. prenanti), an endemic species in the Jinsha river basin, was tested for volitional swimming behavior in a self-designed open-channel flume. Quantified indices, describing preferred hydraulic characteristics, swimming strategies, and swimming speeds, were collected to analyze fish behavioral responses to turbulent flow. The results showed that S. prenanti preferred to select regions with low flow velocities (0.25–0.50 m/s) and turbulent kinetic energy (<0.05 m2/s2) and employed steady swimming behavior to search for flow velocities lower than the average current to conserve energy in low- and moderate-flow regimes. Additionally, the average and maximum burst speeds of S. prenanti were 2.63 ± 0.37 and 3.49 m/s, respectively. The aim of this study was to apply fish volitional swimming behavior data on the the design and optimization of fishways for specific target species, as well as a novel test method for other migratory fish species.Effective fishway design requires knowledge of fish swimming behavior in streams and channels. Appropriate tests with near-natural flow conditions are required to assess the interaction between fish behavior and turbulent flows. In this study, the volitional swimming behavior of S. prenanti was tested and quantified in an open-channel flume with three (low, moderate, and high) flow regimes. The results showed that, when confronted with alternative flow regimes, S. prenanti preferred to select regions with low flow velocities (0.25–0.50 m/s) and turbulent kinetic energy (<0.05 m2/s2) for swimming, while avoiding high-turbulence areas. Moreover, S. prenanti primarily employed steady swimming behavior to search for flow velocities lower than the average current to conserve energy in low- and moderate-flow regimes. It is hypothesized that in regions with higher flow velocities, fish may change their swimming strategy from energy conservation to time conservation. Additionally, the average and maximum burst speeds of S. prenanti were 2.63 ± 0.37 and 3.49 m/s, respectively, which were 2.21- and 2.28-fold higher than the average (1.19 m/s) and maximum (1.53 m/s) burst speeds estimated from the enclosed swim chamber for fish of similar length. This study contributes a novel research approach that provides more reliable information about fish volitional swimming behavior in natural habitats, as well as recommendations for hydraulic criteria for fishways and the identification of barriers to fish migrations.

DEUTERON INDUCED FUSION REACTION TARGET FOR INERTIAL CONFINEMENT FUSION (ICF)

Objective: Energy efficiency enhancement is one of the most effective ways to achieve Fast ignition (FI) in inertial confinement fusion ICF. High energy output gain is essential for ICF reactors and greater energy efficiency can reduce energy costs. The injection of Ion beam is one method used to achieve FI fusion reaction in ICF. A fusion of deuteron with lithium-6 isotope, DLi6 is reviewed in this work alongside the fusion of Deuterium – Tritium (DT), Deuterium – Deuterium (DD), Deuterium – Helium-3 (DHe3) and Proton – Boron-11 (PB11).&#x0D; Materials and Methods: In this work, it is proposed the projection of laser-driven deuteron beam in the FI scheme for ICF in the DLi6 plasma. Fusion occurs as the projected deuteron ion beam hits the lithium-6 target in the thermonuclear fusion reaction.&#x0D; Results: The results show that the fusion reactions of DD, DHe3 and PB11 all require high input kinetic energy (Mega-electronvolts) for the fusion process to occur because of higher Coulomb barrier and the probability of fusion increases by increasing the input energy drive with low output energy gain. DT fusion which require low input kinetic energy of about 400 KeV with high cross section and generated considerable high output energy gain of about 17.59 MeV, However this fusion reaction require large tritium inventory and tritium does not occur naturally, therefore the need for tritium breeding. When the energy of deuteron beam is projected at 200 keV to lithium-6 isotope target, although D + Li6 has a low total cross section of about 19.409 mbarn, the stopping power of the electrons would be more than ions, nuclear stopping power is considerable at very low deuterons energies, the Coulomb interaction of deuteron and lithium-6 occurs with output energy gain of about 22.373 MeV.&#x0D; Conclusion: The investigations indicate that fusion target energy gain efficiency is independent of lithium-6 numerical density. The highest value of energy efficiency gain occurs with lower input kinetic energy of deuteron beam of about 200 KeV to lithium-target.&#x0D; Recommendation: This findings contribute to the core mission of NIF in achieving fast ignition with low ignition energy input to achieve Lawson break-even or "ignition" point of the fusion fuel pellet, where it gives off 100% or more energy than it absorbs. However the simulation results were based on programmed model of Geant4 Hadr03. This results can be validated with the appropriate experimental design of the Hadr03 process.

Strong-field ionization of argon: Electron momentum spectra and nondipole effects

We investigate the influence of relativistic nondipole effects on the photoelectron spectra of argon, particularly in the low kinetic energy region (0 eV - 5 eV). In our experiment, we use intense linearly polarised 800 nm laser pulse to ionise Ar from a jet and we record photoelectron energy and momentum distributions using a reaction microscope (REMI). Our measurements show that nondipole effect can cause an energy-dependent asymmetry along the laser propagation direction in the photoelectron energy and momentum spectra. Model simulation based on time-dependent Dirac equation (TDDE) can reproduce our measurement results. The electron trajectory analysis based on classical model reveals that the photoelectron which obtains negative momentum shift along laser propagation direction is caused by the interplay between the Lorenz force induced radiation pressure during its free propagation in continuum and re-scattering by Coulomb potential of the parent ion when it is driven back by the laser field.

Anisotropy Measurements from the Near-Threshold Photodissociation of the N2-NO Complex.

We have used velocity map ion imaging to measure the angular anisotropy of the NO (A) products from the photodissociation of the N2-NO complex. Our experiment ranged from 108 to 758 cm-1 above the threshold energy to form NO (A) + N2 (X) products, and these measurements reveal, for the first time, a strong angular anisotropy from photodissociation. At 108 cm-1 above the photodissociation threshold, we observed NO (A) photoproducts recoil preferentially perpendicular to the laser polarization axis with an average anisotropy parameter, β = -0.25; however, as the available energy was increased, the anisotropy increased, and at 758 cm-1 above the threshold energy, we found an average β = +0.28. The observed changes in the angular anisotropy of the NO (A) photoproduct are qualitatively similar to those observed for the photodissociation of the Ar-NO complex and likely result from changes in the region of the excited state potential energy surface accessed during the electronic excitation. At the lowest available energy, we also noted a large contribution from hotband excitation; however, this contribution decreased as the available energy increased. The outsized contribution at the lowest available energy may result from hotbands having better Franck-Condon overlap with the excited electronic state near threshold. Finally, we contrast the experimental center of mass translational energy distribution with a statistical energy distribution determined from phase space theory. The experimental and statistical distributions show pronounced disagreement, particularly at low kinetic energies, with the experimental one showing less dissociation resulting in high rotational levels of the fragments.

SN 2020kyg and the rates of faint Iax supernovae from ATLAS

ABSTRACT We present multiwavelength follow-up observations of the ATLAS discovered faint Iax supernova SN 2020kyg that peaked at an absolute magnitude of Mg ≈ −14.9 ± 0.2, making it another member of the faint Iax supernova population. The bolometric light curve requires only ≈7 × 10−3 M⊙ of radioactive 56Ni, with an ejected mass of Mej ∼ 0.4 M⊙ and a low kinetic energy of E ≈ 0.05 ± 0.02 × 1051 erg. We construct a homogeneous volume-limited sample of 902 transients observed by ATLAS within 100 Mpc during a 3.5 yr span. Using this sample, we constrain the rates of faint Iax (Mr ≳ −16) events within 60 Mpc at $12^{+14}_{-8}{{\ \rm per\ cent}}$ of the SN Ia rate. The overall Iax rate, at $15^{+17}_{-9}{{\ \rm per\ cent}}$ of the Ia rate, is dominated by the low-luminosity events, with luminous SNe Iax (Mr ≲ −17.5) like 2002cx and 2005hk, accounting for only $0.9^{+1.1}_{-0.5}{{\ \rm per\ cent}}$ of the Ia rate (a 2σ upper limit of approximately 3 per cent). We favour the hybrid CONe WD + He star progenitor channel involving a failed deflagration of a near Chandrasekhar mass white dwarf, expected to leave a bound remnant and a surviving secondary companion, as a candidate explanation for faint Iax explosions. This scenario requires short delay times, consistent with the observed environments of SNe Iax. Furthermore, binary population synthesis calculations have suggested rates of $1\!-\!18{{\ \rm per\ cent}}$ of the SN Ia rate for this channel, consistent with our rate estimates.

Effects of Multi-Wall Carbon Nanotubes (MWCNT) on Performance of Water Based Mud (WBM)

The present review article expresses the effectiveness of different types of Multi-Wall Carbon Nanotube(s) (MWCNT) on the rheological properties of Water-Based Mud drilling fluid. Shale formations are troublesome according to their water sensitivity characteristic, low Nano-Darcy permeability with small nanometer-sized pore throats that are not effectively sealed by the solids in conventional drilling fluids. Water invasion into the shale formations causes different problems in the drilling industry. Nanoparticle additives have the potential to be used in drilling operations due to their large surface area and lower kinetic energy than micro-additives. The test results demonstrate that multi-wall carbon nanotube improves the rheological properties of the WaterBased Mud drilling fluid. Acidic-surface modified carbon nanotube in the presence of Polyethylene Glycol (PEG) increases the plastic viscosity and yield point of the sample more than unmodified carbon nanotube and hybrid multiwall carbon nanotube. Test results show that multi-wall carbon nanotubes (MWCNT) improve shale stability and shale recovery, finally leading to more well-bore stability in shale formations.

Influence of the nanostructure on the electric transport properties of resistive switching cluster-assembled gold films

The use of Au clusters produced in the gas phase and deposited at low kinetic energy on a substrate allows the bottom-up fabrication of nanostructured metallic thin films with an extremely large number of interfaces, grain boundary junctions and crystal lattice defects. Cluster-assembled gold films exhibit non-ohmic electrical transport properties with a complex resistive switching behavior, exploring discrete resistance states which depend on their structural features (average thickness, resistance value reached on the percolation curve). Their electric conduction properties can be modelled in terms of complex networks of nanojunctions and used to perform binary classification of Boolean functions. The fabrication of devices based on cluster-assembled Au films and exploiting emergent complexity and collective phenomena requires a deep understanding of the influence of the nanoscale structure on the fundamental mechanisms of electrical conduction. Here we present a detailed study of the correlation between the nanostructure and the electrical properties of cluster-assembled gold films by a systematic characterization of the film growth from sub-monolayer to continuous layer beyond the electrical percolation threshold. The influence of different cluster size distributions on the onset of the electrical conduction and the role of defects is investigated by combining in situ and ex situ electrical and structural characterizations.

Comparisons of Spray Characteristics between Non-circular and Circular Nozzles with Rotating Sprinklers

HighlightsExperiments were conducted to investigate the hydraulic performance of the solid-set rotating sprinkler.The effects of nozzle shape and working pressure on the droplet characteristics and kinetic energy of the rotating sprinkler were analyzed.The circular nozzle has a large wetting radius and large droplet size.Use of a non-circular nozzle could result in higher irrigation uniformity and lower kinetic energy imparted to the soil surface by water droplets under low working pressures.Abstract. Reducing the working pressure of sprinklers can effectively reduce sprinkler irrigation energy requirements. However, the reduction in working pressure and variation of nozzle shape inevitably lead to changes in the hydraulic performance of the sprinkler. To evaluate the spray characteristics of selected non-circular (the shape of the nozzle opening was asymmetric) and circular nozzles at low pressure, experiments were conducted to investigate the effects of working pressure, nozzle shape, and nozzle diameter on flow rate, radius of throw, water application rate, droplet size, droplet velocity of the rotating sprinkler, and kinetic energy of the water droplets impacting on the soil surface. The coefficients of irrigation uniformity were calculated for the non-circular and circular nozzles under different rectangular sprinkler spacing and working pressures. The results show that the flow rates of the non-circular and circular nozzles were equal under the same working pressure and with the same nozzle size, while the throw radius of the circular nozzle was longer than that of the non-circular nozzle. The circular nozzle produced a larger droplet size than the non-circular nozzle did. Since the droplet size and kinetic energy per unit droplet volume increased along the radius of throw, and the peak water application rate of the circular nozzle was located near the perimeter of the radius of throw, the peak specific power impact on the soil surface by the water droplets of the circular nozzle was greaterspecifically, 1.26 to 1.97 times that of the non-circular nozzle. With the increase in working pressure, the peak values of specific power and water application rate decreased. The irrigation uniformity coefficients of the non-circular and circular nozzles were more than 85% within the recommended pressure range of the manufacturer when the sprinkler spacing was less than 11 m. It was easier to obtain higher irrigation uniformity and lower impact kinetic energy under low working pressure when using a non-circular nozzle. Keywords: Application rate, Irrigation uniformity, Kinetic energy, Sprinkler irrigation, Working condition.

On analysis and stochastic modeling of the particle kinetic energy equation in particle-laden isotropic turbulent flows

We analyze three-dimensional particle-laden, isotropic turbulence to develop an understanding of inertial particle dynamics from a kinetic energy perspective. Data trends implying inhomogeneous sampling of the flow by particles are identified and used to support a proposed particle behavior: particles appear to accumulate in regions of low flow kinetic energy over time because they lose kinetic energy and slow down in such regions, ultimately causing them to spend more time there. To elucidate this behavior, we derive a particle kinetic energy equation from the particle momentum equation, which incorporates inertial effects through the Schiller–Naumann drag correlation. Upon extracting fundamental physics from this equation, hypotheses regarding the role of the Stokes number in the temporal change of particle kinetic energy and the previously proposed particle behavior are evaluated using simulation data considering three Stokes numbers. Finally, a Fokker–Planck equation is used to derive the steady-state probability density function of the particle kinetic energy. The model fits the simulation data well and provides a tool for further investigation into understanding preferential concentration, as well as a reduced order model for predicting particle kinetic energy in turbulent flows.