Maximum Transport Efficiency Research Articles

Optimizing Ion Optical Design for Laser Ablation Source in Mass Spectrometry

The study focuses on optimizing a Laser Ablation Source (LAS) for use in mass spectrometry, particularly aiming to enhance transmission of ions and and determination of isotopic compositions in diverse matrices at TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN). Critical variables affecting mass spectrometer resolution, such as ion kinetic energy distribution and ion transport are optimized through LAS. The paper explores the importance of consistent initial conditions, ion transport efficiency, and ion capture for accurate and reproducible measurements. Using SIMION software, we optimized ion optical design to tackle challenges like collimating ions travelling off-axis and mass filtering. A significant part of the study is dedicated to ion optic design to enable low abundance measurement of ions of interest (e.g., 10 ions of interest out of 1014 total ions). Techniques like high voltage switching and beam shaping were explored, and the final design aims for high transport efficiency and a 4 mm effective target scan area with maximum transport efficiency. The integration of LAS with a Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) is expected to yield an analytical tool with high spatial resolution and transport efficiency for isotope abundance measurement.

A case study with extreme low-level jet in southern Brazil

This study aimed to analyze a period of intense Low-Level Jets (LLJ) in southern Brazil that occurred in a year of intense El Nino-South Oscillation signal. Observational data were collected by radiosonde data carried out at Salgado Filho airport, which measured values of the order of 30 ms-1 in intensity at 700/750 meters in height and a predominant direction of 270 degrees. The LLJ’s are horizontal vortices in the low-level turbulence process, optimizing the transport of energy and water vapor at the mesoscale; they are low-cost energy structures with maximum transport efficiency. In general, their modeling by numerical models at high resolution is difficult because they have a thin layer with a small thickness of the order of 50 meters and have a non-linear nature in the turbulence processes. However, global reanalysis models, in general, cannot represent the optimization effects in the turbulent process performed by LLJ. However, there is a tendency to represent the magnitude of the wind modulus, an approximation of this value by the current state of the art in global reanalysis modeling in models, in this case, the maximum wind. This implies that global models generally underestimate flows at low levels, in general, as they do not represent the optimization effects associated with LLJ. In this case study, we tried to use an extreme situation of occurrence of LLJ for analysis, therefore, the regional climate model RegCM-4.9 in high spatial resolution was used to simulate the period from May to June 1997. The analyses were concentrated in June 1997. The initialization and boundary conditions were used from the EC-EARTH historical of the Earth system model based on the operational seasonal forecast system of the European Center for Medium-Range Weather Forecasts (ECMWF). It was observed that the simulation result could significantly underestimate the wind intensity and the processes associated with the LLJ with the initialization model, with low information resolution, the global initialization models do not have adequate resolution for this type of simulation.

Transporting Cold Atoms towards a GaN-on-Sapphire Chip via an Optical Conveyor Belt

Trapped atoms on photonic structures inspire many novel quantum devices for quantum information processing and quantum sensing. Here, we demonstrate a hybrid photonic-atom chip platform based on a GaN-on-sapphire chip and the transport of an ensemble of atoms from free space towards the chip with an optical conveyor belts. Due to our platform’s complete optical accessibility and careful control of atomic motion near the chip with a conveyor belt, successful atomic transport towards the chip is made possible. The maximum transport efficiency of atoms is about 50% with a transport distance of 500 μm. Our results open up a new route toward the efficient loading of cold atoms into the evanescent-field trap formed by the photonic integrated circuits, which promises strong and controllable interactions between single atoms and single photons.

Low-cost photoreactors for highly photon/energy-efficient solar-driven synthesis

Low-cost photoreactors for highly photon/energy-efficient solar-driven synthesis

Nature‐Inspired Interconnected Macro/Meso/Micro‐Porous MXene Electrode

AbstractThe geometric multiplication development of MXene has promoted it to become a star material in numerous applications including, but not limited to, energy storage. It is found that pore structure modulation engineering can improve the inherent properties of MXene, in turn significantly enhancing its electrochemical performance. However, most of the current works have focused on exploring the structure‐effective relationships of the single‐scale pore structure regulation of MXene. Inspired by Murray's law from nature where a highly graded structure of the organisms is discovered and used to achieve effective diffusion and maximize mass transfer, a hierarchically interconnected porous MXene electrode across micro‐meso‐macroporous is constructed. This MXene‐based electrode provides large amounts of active sites while greatly shortening the ion diffusion channel. Finally, the zinc ion microcapacitor based on this MXene electrode exhibits an ultrahigh area‐specific capacitance up to 410 mF cm−2 and an energy density up to 103 µWh cm−2 at a power density of 2100 µW cm−2. The areal energy density outperforms the currently reported zinc ion microcapacitors. This study supports an effective strategy for electrode materials (including but not limited to MXene) to achieve ultra‐short ion diffusion channels and maximum transport efficiency for next‐generation high‐performance energy storage.

Transport Efficiency of Continuous-Time Quantum Walks on Graphs.

Continuous-time quantum walk describes the propagation of a quantum particle (or an excitation) evolving continuously in time on a graph. As such, it provides a natural framework for modeling transport processes, e.g., in light-harvesting systems. In particular, the transport properties strongly depend on the initial state and specific features of the graph under investigation. In this paper, we address the role of graph topology, and investigate the transport properties of graphs with different regularity, symmetry, and connectivity. We neglect disorder and decoherence, and assume a single trap vertex that is accountable for the loss processes. In particular, for each graph, we analytically determine the subspace of states having maximum transport efficiency. Our results provide a set of benchmarks for environment-assisted quantum transport, and suggest that connectivity is a poor indicator for transport efficiency. Indeed, we observe some specific correlations between transport efficiency and connectivity for certain graphs, but, in general, they are uncorrelated.

Cross-Sectional Dimension Dependence of Electroosmotic Flow in Fractal Treelike Rectangular Microchannel Network.

The present work theoretically and numerically studies the electroosmotic flow (EOF) within a fractal treelike rectangular microchannel network with uniform channel height. To obtain minimum EOF fluidic resistance, the microchannel cross-sectional dimensions of the fractal network are optimized. It is found that the cross-sectional dimension dependence of EOF fluidic resistance within a symmetric fractal network is only dependent on the channel width when the total channel volume is constant, and the optimal microchannel widths to reach the minimum EOF fluidic resistance satisfy the scaling law of κ = N−1 (where κ is the width ratio of the rectangular channels at two successive branching levels, N is the branching number); however, for the symmetric fractal network with constant total surface area, the optimal cross-sectional dimensions should simultaneously satisfy κ = N−1 and (where H is the channel height, S is the total channel surface area, l0 is the channel length at the original branching level, γ is the channel length ratio at two successive branching levels and m is the total branching level) to obtain the minimum EOF fluidic resistance. The optimal scaling laws established in present work can be used for the optimization design of the fractal rectangular microchannel network for EOF to reach maximum transport efficiency.

ELECTROOSMOTIC FLOW IN TREE-LIKE BRANCHING MICROCHANNEL NETWORK

As a kind of microchannel layout with good transport performance, tree-like branching microchannel network has been widely used for microfluidic systems, however, the optimal analysis of the tree-like branching microchannel network for electroosmotic flow (EOF) to reach a minimized fluidic resistance still needs a deep study. In this work, the EOF in tree-like branching microchannel network is theoretically and numerically studied. It is found that there is an optimal structure of the tree-like branching network for the EOF to achieve a minimum fluidic resistance under the size constraint of constant total channel volume. This work found that the optimal channel radii of the tree-like network for EOF to reach a minimum fluidic resistance satisfy the relationship of [Formula: see text], where [Formula: see text] is the radius of the parent channel, [Formula: see text] is the radius of the child channels and [Formula: see text] is the total number of child channels. This formula can be regarded as an extended Murray’s law for EOF and is helpful for the optimization design of tree-like branching microchannel network for EOF to reach maximum transport efficiency under the constant applied driven voltage.

Bulk Liquid Membranes for Separation and Recovery of Pharmaceutical Products

In this present paper the behavior of two important pharmaceutical compounds, namely: nicotinic acid (vitamin PP/B3) and para-aminobenzoic acid (vitamin B10) to the transport through a liquid membrane of chloroform containing Aliquat 336 have been studied. The influence of operational parameters such as: solute concentration in the feed phase, stripping agent concentration in the stripping phase, transport time was monitored. The assessment of the obtained results allowed establishing of optimal transport conditions as well as identification of a kinetic transport model for nicotinic acid corresponding to consecutive irreversible 1st order reactions. The maximum transport efficiency was 96% and it was obtained at a concentration of 10-4 mol/L nicotinic acid in the feed phase and a concentration of 1 mol/L sodium hydroxide in the stripping phase. The transport time necessary to achieve this efficiency was 6 h. The results obtained led to important conclusions regarding the possibility of separating these two compounds. Analytical control of the process was done spectrophotometrically. The maximum absorbance was obtained at their characteristic wavelengths, namely 262 nm for nicotinic acid and respectively 267 nm for para-aminobenzoic acid.

In Vitro Study of Receptor-Mediated Silica Nanoparticles Delivery across Blood-Brain Barrier.

A brain drug delivery system has been demonstrated by attaching lactoferrin (Lf) on the silica nanoparticles (Si NPs). The nanoparticle surface was modified with polyethylene glycol to reduce protein adsorption. The transport efficiency of Lf attached Si NPs was studied using an in vitro blood-brain barrier (BBB) model consisting of three distinct types of cells: endocytes, pericytes, and astrocytes. Transfer of NPs from the apical side to the basolateral side is observed. The results indicated that Lf attached Si NPs demonstrated enhanced transport efficiency across the BBB with size-dependence compared to bare Si NPs. The maximum transport efficiency of lactoferrin conjugated silica nanoparticle was observed for 25 nm diameter particles. This receptor-mediated transcytosis of Si NPs across the cerebral endothelial cells can be employed to deliver drugs and imaging probes to the brain.

Transport of carboxymethyl cellulose-coated zerovalent iron nanoparticles in a sand tank: Effects of sand grain size, nanoparticle concentration and injection velocity

The transport of nanoscale zerovalent iron (NZVI) particles colloidally stabilized with 70,000 Da carboxymethyl cellulose (CMC), through sands with mean grain diameters of 180, 340 and 1140 μm (referred to as fine, intermediate and coarse-sized sand, respectively) was investigated in a 70-cm long, two-dimensional tank. The effect of NZVI concentrations (1 and 3 g-Fe L−1) and CMC concentrations (1 and 2 g L−1) and injection velocities (0.96 and 0.40 cm min−1) on particle transport were also evaluated with the intermediate sand. The overall NZVI mass fractions eluted from the tank were 36%, 25% and 16% in the coarse, intermediate and fine sands, respectively, when injected with 1 g L−1 NZVI stabilized in 1 g L−1 CMC. However, the mass fraction eluted reduced to 2.33% when the injection velocity was reduced from 0.96 to 0.40 cm min−1 in the intermediate-sized sand. Maximum transport efficiency (38% NZVI mass eluted) in the intermediate-sized sand was achieved with 3 g L−1 NZVI suspended in 2 g L−1 CMC at an injection velocity of 0.96 cm min−1. The transport efficiency was substantially decreased (11% NZVI mass eluted) when 3 g L−1 NZVI was stabilized with only 1 g L−1 CMC. The NZVI mean particle diameters in the porewaters remained unchanged at different locations in the tank suggesting that straining or gravity settling did not influence NZVI deposition. After NZVI injection, the hydraulic conductivity in the tank reduced by 80%–96%, depending on the CMC concentration and injection velocity.

Production of high intensity 48Ca for the 88-Inch Cyclotron and other updates

Recently the Versatile ECR for NUclear Science (VENUS) ion source was engaged in a 60-day long campaign to deliver high intensity (48)Ca(11+) beam to the 88-Inch Cyclotron. As the first long term use of VENUS for multi-week heavy-element research, new methods were developed to maximize oven to target efficiency. First, the tuning parameters of VENUS for injection into the cyclotron proved to be very different than those used to tune VENUS for maximum beam output of the desired charge state immediately following its bending magnet. Second, helium with no oxygen support gas was used to maximize the efficiency. The performance of VENUS and its low temperature oven used to produce the stable requested 75 eμA of (48)Ca(11+) beam current was impressive. The consumption of (48)Ca in VENUS using the low temperature oven was checked roughly weekly, and was found to be on average 0.27 mg/h with an ionization efficiency into the 11+ charge state of 5.0%. No degradation in performance was noted over time. In addition, with the successful operation of VENUS the 88-Inch cyclotron was able to extract a record 2 pμA of (48)Ca(11+), with a VENUS output beam current of 219 eμA. The paper describes the characteristics of the VENUS tune used for maximum transport efficiency into the cyclotron as well as ongoing efforts to improve the transport efficiency from VENUS into the cyclotron. In addition, we briefly present details regarding the recent successful repair of the cryostat vacuum system.

Calix[4]arene derivative bearing imidazole groups as carrier for the transport of palladium by using bulk liquid membrane

The carrier activity of calix[4]arene containing imidazole groups towards the facilitated transport of palladium(II) through dichloromethane bulk liquid membrane has been studied. The optimum transport conditions were established by the studies on the effect of pH, feed concentration, carrier concentration, receiver phase concentration and transport time. A solution of 1M hydrochloric acid (HCl) served as receiving phase for maximum transport of the metal ion. Maximum transport efficiency was observed for Pd(II) ion when it was present in the concentration of 10−3M and the transport efficiency after 24h was found as 95%.

Simulation Analysis of Transmission-Line Impedance Transformers for Petawatt-Class Pulsed Power Accelerators

Based on the transmission line code TLCODE, a 1D circuit model for a transmission-line impedance transformer was developed and the simulation results were compared with those in the literature. The model was used to quantify the efficiencies of voltage-transport, energy-transport and power-transport for a transmission-line impedance transformer as functions of ψ (the ratio of the output impedance to the input impedance of the transformer) and Γ (the ratio of the pulse width to the one-way transit time of the transformer) under a large scale of m (the coefficient of the generalized exponential impedance profile). Simulation results suggest that with the increase in Γ, from 0 to ∞, the power transport efficiency first increases and then decreases. The maximum power transport efficiency can reach 90% or even higher for an exponential impedance profile (m = 1). With a consideration of dissipative loss in the dielectric and electrodes of the transformer, two representative designs of the water-insulated transformer are investigated for the next generation of petawatt-class z-pinch drivers. It is found that the dissipative losses in the electrodes are negligibly small, below 0.1%, but the dissipative loss in the water dielectric is about 1% to 4%.

Simulation of Railway Network Based on Cellular Automaton Model with Conflict Resolution

Cellular automata (CA) models are the idealization of physical systems with assumed discrete space and time and a finite number of discrete state transition of cells. Utilizing the CA model, we can capture and reveal the dynamics of railway traffic system. In this paper, the improved CA models are proposed to demonstrate the dynamic behavior of trains with conflict resolution. We propose the CA models to simulate the railway traffic network in the moving-block system, and reschedule trains by applying such two scheduling strategies as FCFS (first come first served) and FLFS (first leave first served). We analyze the relationship between the total delay and time interval of departure utilizing the proposed models. The simulation results demonstrate the rational conclusion that FLFS can cause less delay than FCFS. The proposed models can facilitate finding which plan can achieve the maximum transport efficiency for the railway network.

Transport of silver ions through a flat-sheet supported liquid membrane

Abstract Toxic metals from industrial wastewaters are an important environmental issue. The use of supported liquid membrane processes has gained momentum in recent years, as it allows the reuse of water and toxic metals. The aim of this study is to investigate the active transport of silver ion through a supported liquid membrane (micro-porous Fluoropore PTFE) of DC18C6 (Dicyclohexano18crown6) in toluene under various experimental conditions. For this purpose, the effects of various parameters including binary carriers, carrier concentration, feed phase concentration, the nature and concentration of stripping agents in the stripping phase and flow rates of feed and stripping phases on transport efficiency were also investigated. The maximum transport efficiency was observed at the following conditions: flow rates of 50 mL/min in both phases, 0.05 M DC18C6 in toluene as carrier solution, 50 ppm Ag+ dissolved in 0.015 M HNO3 as feed solution and 0.08 M Na2S2O3 as stripping solution Optimum operation time was determined as 240 min. Under these conditions, 94% of the silver ions were transported from the feed phase to the membrane phase. However, the transport rate from the membrane phase to the stripping phase remained at approximately 81%.

Selective transport of copper across a bulk liquid membrane using 8-hydroxy quinoline as carrier

The carrier activity of 8-hydroxy quinoline (oxine) towards the facilitated transport of copper ions through chloroform bulk liquid membrane has been studied. The effects of pH of the source phase, the nature of stripping agents in the receiving phase, presence of other cations, nature of synergistic reagents on the transport were investigated. A solution of 0.1 M nitric acid (HNO 3) served as receiving phase for maximum transport of the metal ion. Addition of 2-amino pyridine to the membrane phase had a synergistic effect and caused a pronounced enhancement in the transport, while citric acid or glycine did not change the transport significantly. Maximum transport efficiency was observed for Cu 2+ ion when it was present in the concentration of 10 −4 M. Tolerance to the presence of Pb 2+, Zn 2+, Cd 2+, Ni 2+, Fe 2+ and Fe 3+ ions was investigated and it was found that Cu 2+ transport was not affected even in the presence of 10-fold concentration of these ions. This system was applied for the recovery of copper in electroplating industrial waste water samples.

Membrane transport of metal ions by bisdithiophosphonyl podands

Methods of membrane extraction play an important role in technological processes for selective separation of mineral, organic, and biological substrates [1]. Earlier we studied the membrane transport of alkali and alkaline earth metals with phosphorylated azapodands and established the maximum transport efficiency where the metal ion size and pseudocavity formed by the podand are complementary to each other [2, 3]. In the present work we used S-alkyl diesters of bisaryldithiophosphonic acids I–V in the transport through liquid membrane of copper(II), barium(II), and lead(II) ions differing both in the their atomic radii and ability to form coordination compounds with sulfur-containing ligands. The description of synthesis methods and some properties of podands is given in [3–6]. DOI: 10.1134/S1070363210010251

Transport of silver ion through bulk liquid membrane using macrocyclic and acyclic ligands as carriers in organic solvents

The bulk liquid membrane transport of silver (I) ion was studied by dibenzopyridino-18-crown-6(DBPY18C6), 4-nitrobenzo-15-crown-5(NB15C5), 2-aminothiaphenol and a new synthesized ligand, 1,4-dioxa-7,10-dithiacyclododecane-2,3-dione as carriers in nitrobenzene (NB). The effects of pH on the source phase and receiving phase, the nature and concentration of stripping agents in the receiving phase and the picrate concentration as counter ion in source phase were investigated. The results show that the efficiency of transport of the Ag+ ion through membranes, changes with the nature of the ligand. The efficiency transport increases for the ligands with donating nitrogen and sulfur atoms with respect to oxygen donor atoms. Maximum transport efficiency was observed for silver (I) ion in the presence of thiosulfate ion ( \( {\text{S}}_{{\text{2}}} {\text{O}}^{{2-}}_{{\text{3}}} \)) as a suitable stripping agent. The results show that the sequence of transport efficiency for Ag+ ion using DBPY18C6, NB15C5, 2-aminothiaphenol and 1,4-dioxa-7,10-dithiacyclododecane-2,3-dione as carriers in organic solvents is: nitrobenzene > dichloromethane > 1,2- dichloroethane > chloroform.

The relevance of xylem network structure for plant hydraulic efficiency and safety

The xylem is one of the two long distance transport tissues in plants, providing a low resistance pathway for water movement from roots to leaves. Its properties determine how much water can be transported and transpired and, at the same time, the plant's vulnerability to transport dysfunctions (the formation and propagation of emboli) associated to important stress factors, such as droughts and frost. Both maximum transport efficiency and safety against embolism have classically been attributed to the properties of individual conduits or of the pit membrane connecting them. But this approach overlooks the fact that the conduits of the xylem constitute a network. The topology of this network is likely to affect its overall transport properties, as well as the propagation of embolism through the xylem, since, according to the air-seeding hypothesis, drought-induced embolism propagates as a contact process (i.e., between neighbouring conduits). Here we present a model of the xylem that takes into account its system-level properties, including the connectivity of the xylem network. With the tools of graph theory and assuming steady state and Darcy's flow we calculated the hydraulic conductivity of idealized wood segments at different water potentials. A Monte Carlo approach was adopted, varying the anatomical and topological properties of the segments within biologically reasonable ranges, based on data available from the literature. Our results showed that maximum hydraulic conductivity and vulnerability to embolism increase with the connectivity of the xylem network. This can be explained by the fact that connectivity determines the fraction of all the potential paths or conduits actually available for water transport and spread of embolism. It is concluded that the xylem can no longer be interpreted as the mere sum of its conduits, because the spatial arrangement of those conduits in the xylem network influences the main functional properties of this tissue. This brings new arguments into the long-standing discussion on the efficiency vs. safety trade-off in the plants’ xylem.