Commercial Mobility Research Articles

The investigation of traceable preparation technique of submicron particle number concentration standards in liquids

The concentration of particles at the nano- and submicron-meter scale in liquid is crucial in multiple fields including the biomedical and semiconductor industry. However, there is still a lack of metrological standards or Certified Reference Materials (CRMs) for liquid-borne particle number concentration (PNC) which could be traceable to the International System of Units (SI). To address this issue, a quantitative and value-traceable preparation technique for liquid-borne particle number concentration CRMs (PNC-CRMs) in a submicron-meter scale based on controllable aerosol generation and collection was developed in this study. In this technique, by using commercial differential electrostatic mobility analyzer (DMA) and calibrated condensation particle counter (CPC), monodisperse aerosol particle with known concentration was initially generated. Then for quantitatively transforming the aerosol particles to the liquid, an aerosol particle collection system was designed and developed by hydrodynamic (CFD) simulations and experiment conducting, and crucial parameters of the collection system, e.g. the nozzle diameter of the aerosol particle outlet, the distance from the nozzle to the liquid surface, and the state of the liquid interface, were investigated and optimized. Under the optimized collected parameters, the collection efficiency for aerosol particles of the newly-developed system could reach over 90%. Because the PNC in aerosol is SI-traceable, combined with the obtained collection efficiency and collection time, the PNC in the collection liquid with could be obtained finally and trace to SI unit. Using this technique, two kinds of PNC-CRMs with nominal sizes of 100 and 500 nm were developed successfully, where, certified values were (7–9) × 106 particles/mL and 1.7 × 106 particles/mL, and standard uncertainties are 4.2%.

Tungsten Nanoparticles Generated in an Atmospheric Pressure Plasma Jet

AbstractThe atmospheric pressure plasma source HelixJet has been used to generate tungsten nanocrystals with narrow size distributions, well defined size control and with a considerably good particle yield. Tungsten particles are produced as the result of an evaporation process of a tungsten wire inserted on the middle axis of the jet after the wire is heated by interaction with the plasma. Temperature measurements using a thermocouple and by optical emission spectroscopy showed that, while the overall temperature of the wire is very high, it is not in the range of the melting temperature of tungsten; however, it can reach values needed for sublimation. Additionally, the wire is heated selectively while the temperature of the jet components reaches only a few hundred degrees Celsius. The particles cluster into agglomerates and their formation has been analyzed in relation to the reliability of a commercial scanning mobility particle sizer spectrometer. The dependence of the particle morphology and crystal structure on the plasma parameters such as power and gas flow was studied via transmission electron microscopy and the average size of the tungsten nanocrystals could be tuned between 12 and 25 nm.

High-throughput approach for investigating interdiffusion in medium- and high-entropy alloys

Interdiffusion experiments are usually time-consuming and tedious since diffusion couples must be annealed at several temperatures for a long time. The efforts required to study interdiffusion in multicomponent alloys increase dramatically as multiple diffusion couples are required to cover broad composition ranges and determine the diffusivities of individual elements in different chemical environments. To circumvent this challenge, we present a high-throughput approach applicable to single-phase and compositionally complex alloys, which are assumed to approximate ideal solid solutions. Here, a simple diffusion-multiple experiment combined with a physically based kinetic model is proposed to efficiently determine the diffusion coefficients of the constituent elements in quaternary CrFeCoNi alloys. Compared with tracer diffusivities reported in the literature, the results, thus, obtained do not differ by more than a factor of 2 and were obtained from a single interdiffusion experiment. In contrast, the diffusivities simulated with commercial mobility and thermodynamic databases are strongly overestimated by a factor ranging from 1 to 16. Therefore, our approach enables high-throughput determination of diffusivities and can help in the design of alloys for high-temperature applications where diffusion plays a key role.

Interplatform comparison between three ion mobility techniques for human plasma lipid collision cross sections

The implementation of ion mobility spectrometry (IMS) in liquid chromatography-high-resolution mass spectrometry (LC-HRMS) workflows has become a valuable tool for improving compound annotation in metabolomics analyses by increasing peak capacity and by adding a new molecular descriptor, the collision cross section (CCS). Although some studies reported high repeatability and reproducibility of CCS determination and only few studies reported good interplatform agreement for small molecules, standardized protocols are still missing due to the lack of reference CCS values and reference materials.We present a comparison of CCS values of approximatively one hundred lipid species either commercially available or extracted from human plasma. We used three different commercial ion mobility technologies from different laboratories, drift tube IMS (DTIMS), travelling wave IMS (TWIMS) and trapped IMS (TIMS), to evaluate both instrument repeatability and interlaboratory reproducibility. We showed that CCS discrepancies of 0.3% (average) could occur depending on the data processing software tools. Moreover, eleven CCS calibrants were evaluated yielding mean RSD below 2% for eight calibrants, ESI Low concentration tuning mix (Tune Mix) showing the lowest RSD (< 0.5%) in both ion modes. Tune Mix calibrated CCS from the three different IMS instruments proved to be well correlated and highly reproducible (R2 > 0.995 and mean RSD ≤ 1%). More than 90% of the lipid CCS had deviations of less than 1%, demonstrating high comparability between techniques, and the possibility to use the CCS as molecular descriptor. We highlighted the need of standardized procedures for calibration, data acquisition, and data processing. This work demonstrates that using harmonized analytical conditions are required for interplatform reproducibility for CCS determination of human plasma lipids.

Determination of Resistance to Water-İnduced Damage of Bituminous Mixtures Containing Hydrated Lime Prepared with Different Contents of PVC Waste

Increasing commercial mobility throughout the world has increased the need for roads and as a result, new road networks have emerged. The pavement type of the highways constructed in our country consists of flexible pavements to a significant extent. Parameters such as the number of heavy vehicles, repeated loads as well as environmental and climatic conditions cause different deformations on flexible pavements. One of these deformations is water-induced damage. In particular, changing climatic conditions cause some regions to experience intense precipitation in a very short period of time, which they should receive throughout the year. As a result, flexible pavements are damaged and their service life becomes shorter than expected. With increasing environmental awareness, the use of some waste materials in bituminous mixtures has become an extremely important issue. In this study, bituminous materials modified with different Polyvinyl Chloride (PVC) contents were mixed with properly graded aggregates and their resistance to water-induced damage has been evaluated. In addition, several performance tests were carried out to evaluate the effect of hydrated lime addition on the resistance of the samples to water-induced damage. In this context, the properties of the modified bitumen and aggregates were determined by performing conventional bitumen and aggregate tests. As the final objective of the study, Modified Lottman Test (AASHTO T 283) was performed on the mixtures to determine the effect of PVC addition to bituminous materials on resistance to water-induced damage.

Tourist mobility: sociological theory and implementation practices

The article analyzes the connection between the sociology of tourism and the general sociological theory of mobility, which leads to an understanding of modern tourist mobility not as a process of revealing the will of individuals to learn about different cultures, but as a system of social constructions that exist in the form of tourism practices and are focused on maximizing profits for global tour operators. The methodology. The method of the propositional analysis is aimed at identifying logically based semantic units with the aim of selecting and synthesizing reliable knowledge expressed in texts written on issues of sociology of tourism and the general sociological theory of mobility. Scientific novelty is in clarifying the concept of tourist mobility and tourist practices; in revealing that they are largely the result of commercially oriented social construction carried out in the interests of global tour operators; in demonstrating that commercial and non-commercial tourist mobility entail incompatible social consequences. Conclusions. The article is devoted to current problems of modern sociology of tourism in its connection with the general theory of mobility (one of the founders of which was the British sociologist John Urry) that complemented the “old” theory of social mobility by the doctrine of the movement of people, goods, capital, information, etc. in geographical space. Now society has come to be understood as a mobile structure consisting of many mobile practices (including tourism) that can be aimed at either developing essential strength of people or control over their consciousness and behavior.

Multiphoton Absorption in Gallium Nitride and Silicon Carbide Photodiodes: Applications for Single-Event Effects Tests

We report on the investigation of multiphoton absorption processes in gallium nitride and silicon carbide photodiodes. Up to three-photon absorption mechanisms were evidenced on both materials, thanks to a wavelength-tunable femtosecond laser chain. These results are applied to single event effect investigations on a commercial gallium nitride high electron mobility transistor. We could trigger single event transients by focusing the beam throughout the silicon substrate and collect charge that was photogenerated in the gallium nitride layer by a three-photon absorption process.

INTERRELATIONSHIP OF INFLATION, EXCHANGE RATE AND INTEREST RATES IN THE CONTEXT OF HUNGARY'S STRATEGIC POLICY

INTERRELATIONSHIP OF INFLATION, EXCHANGE RATE AND INTEREST RATES IN THE CONTEXT OF HUNGARY'S STRATEGIC POLICY

The Challenge to Develop the Perfect Flat Panel Satellite Communications Terminal: The Perfect SATCOM Terminal

The large investments in new satellite communications (SATCOM) constellations are driving the demand for flat panel antennas (FPAs). We are already seeing the growing adoption of the technology in commercial and military applications. As more of the new constellations become operational, this adoption is projected to explode. There are a wide range of SATCOM terminal needs across the different market segments that are also dependent on what constellation(s) they might be using. The major markets include consumer, commercial mobility, enterprise, and government. While each of these markets have unique requirements—or limitations—on size, weight, power draw, throughput performance, cost, and ruggedness, there is some overlap, as shown in <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> . Generally, the consumer market can be separated from the other applications, given their unique requirements. While these consumer terminals can meet some needs in all markets, they are very limited outside of their primary use. The other three markets have significantly more overlap in requirements, with ruggedness being a key differentiator from consumer terminals. With that differentiator, prices are higher, most applications can sustain higher power draw, and many demand higher throughput performances. This does not mean that each segment may have some classes of terminals with unique requirements that do not overlap any other.

Evaluation of Mechanically-Assisted Crevice Corrosion of Different Modular Dual Mobility Constructs

BackgroundModular dual mobility (MDM) acetabular component use is rising in total hip arthroplasty. However, concern of mechanically assisted crevice corrosion (MACC) at the shell-liner interface remains. We investigated shell-liner corrosion using retrieval analyses and corrosion chamber testing. MethodsWe analyzed fretting and corrosion on 10 matched pairs of 2 commercial MDM constructs (MDM1 and MDM2). Also, pristine pairs of Ti6Al4V shells and CoCrMo liners from 3 commercial dual mobility systems (MDM1, MDM2, and MDM3) were tested in vitro to model MACC performance. Three pairs of each were placed into an electrochemical chamber with stepwise increasing cyclic compression loads while measuring currents generated at the shell-liner taper. Onset fretting loads and fretting currents were calculated. ResultsCorrosion damage scores on retrieved components were low but higher in the MDM2 to MDM1 liners (P = .006), specifically outside the taper region (P = .00003). Fretting currents were higher in the MDM2 than in MDM1 or MDM3 (P = .011). Onset loads were also higher in the MDM2 (P = .001). ConclusionAmong retrieved liners, MDM2 tapers seem prone to non-mechanical corrosion modes. Higher onset loads and fretting currents in MDM2 tapers indicate greater MACC resistance but higher severity once corrosion begins. Differences among the devices were likely due to taper design and surface finish. Currents in all 3 were <5 μA, much lower than those observed with head-neck tapers. Our findings suggest that, among the types of corrosion observed in these MDM designs, mechanically driven corrosion may not be the most significant.

IPaaS: Intelligent Paging as a Service

Paging is a critical operation in 5G mobile networks for localization of User Equipment (UE) in idle mode. Current multistep paging method increases the signaling exponentially and delay linearly, and analysis of a commercial Access and Mobility management Function (AMF) reports that paging accounts for 27.9% of AMF total traffic. To reduce signaling overhead and service delay by increasing the paging success rate, this paper presents a Deep Learning (DL) driven intelligent Paging as a Service (iPaaS) over a distributed NWDAF architecture based on serverless computing. iPaaS clusters UEs based on their movement patterns and feed cluster ID, movement history, and elapsed time in idle mode of a UE into DL model for UE localization prediction. Prediction results are used in two proposed schemes: iPaaS for Reduced Signaling (iPRS) and iPaaS for Reduced Delay (iPRD), which focus on cutting down signaling overhead and delay, respectively. Performance of iPaaS with two proposed schemes is evaluated on 110 million handover logs that are collected over 15 days from a commercial 5G network. Results show that iPRS reduces the signaling overhead up to 94% and iPRD reduces the delay up to 43% comparing to current method.

Are neighbourhood amenities associated with more walking and less driving? Yes, but predominantly for the wealthy

Cities are home to a vast array of amenities, from local barbers to science museums and shopping malls. But these are unequally distributed across urban space. Using Google Places data combined with trip-based mobility data for Bogotá, Colombia, we shed light on the impact of neighbourhood amenities on urban mobility patterns. By deriving a new accessibility metric that explicitly takes into account spatial range, we find that a higher density of local amenities is associated with a higher likelihood of walking as well as shorter bus and car trips. Digging deeper, we use an effect modification framework to show that this relationship varies by socioeconomic status. Our main focus is walking and driving, finding that amenities within about a 1-km radius from home are robustly associated with a higher propensity to walk and shorter driving time only for the wealthiest group. These results suggest that wealthier groups may weigh the proximity of local amenities more heavily into travel decisions, perhaps based on differentiated time-money trade-offs. As cities globally aim to boost public transport and green travel, these findings enable us to better understand how commercial structure shapes urban mobility in highly income-segregated settings.

Modification of polyester filters with synthesized copper nanoparticles for use as biocide in a real environment.

Antimicrobial air filtration techniques have recently been widely studied to enhance indoor air quality and mitigate hazardous airborne microorganisms. Here, CuNPs were incorporated into a commercial polyester fiber surface and Scanning Mobility Particle Sizer was used to measure the adherence between fibers and nanoparticles. An acid pretreatment previous CuNP incorporation was effective against the particle release and enhanced the adhesion between particle and fiber. CuNP was a mixture of Cu0 and Cu2O with a diameter size of 90 nm (SEM micrographs). The permeability of the filter was low, in order of 10–9 m2. The activity against pathogens was tested in loco in a real environment using a filtration prototype apparatus. It was observed that the presence of CuNP mitigated the fungi and bacteria growth not only on the surface but also reduced microbe concentrations after passing through the filter. These results show that CuNP can be used as an inhibitor of various microorganisms, making them a good alternative for indoor environments to control indoor air quality.

Dual-Band Three-Way Doherty Power Amplifier Employing Dual-Mode Gate Bias and Load Compensation Network

This article presents a new method to design dual-band three-way Doherty power amplifiers (DPAs). A novel modified load modulation network (LMN) is constructed for enabling dual-mode Doherty operation with three-way configuration, providing enhanced high efficiency range in both modes. Moreover, a parallel load compensation network (LCN) is employed in the proposed three-way DPA to provide wideband performance in each operation band. A three-way dual-mode DPA using commercial gallium nitride high electron mobility transistors (GaN HEMTs) is then designed and manufactured to verify the proposed architecture. Frequency bands of 1.45&#x2013;1.9 GHz in Mode I and 0.75&#x2013;1.0 GHz in Mode II are achieved by the DPA, respectively. The fabricated DPA has a 9-dB output back-off (OBO) efficiency of 42.8&#x0025;&#x2013;57.7&#x0025; and a saturated efficiency of 55.4&#x0025;&#x2013;70.1&#x0025;. When driven by a 20-MHz long term evolution (LTE) modulated signal with 8-dB peak-to-average ratio (PAPR), the adjacent channel power ratio (ACPR) of the fabricated DPA is better than &#x2212;49.9 dBc after digital predistortion at 0.9 and 1.7 GHz with average efficiency of 45.7&#x0025; and 54.6&#x0025;.

Portable nanoelectrospray periodic focusing differential ion mobility spectrometer for the rapid screening of illicit drugs

The spread of illicit drug abuse is a major public health issue in most countries. Law enforcement personnel on drug abuse need a tool to confiscate and block illicit trade of illicit drug or monitoring drug impaired driving. Therefore, affordable and portable instruments for illegal drug detection are in critical need. In this study, we developed a portable periodic focusing differential ion mobility (PFDMA) spectrometer for in situ motoring illicit drugs. The device comprised an ionization source, drift cell, air blower, voltage divider board and electronic control board. In general, an ion mobility spectrometer (IMS) is able to work with air as a buffer gas at atmospheric pressure. There is no need to install heavy mechanical and/or expensive turbo molecular pumps. For our instrument, a small air blower was used to generate laminar counterflow. The whole device is compact with a size of 150 × 200 × 280 (WLH, mm) and a weight of 2.5 kg. In general, most commercial drift tube ion mobility spectrometers use radioactive or corona discharge ionization. In this work, we utilized a different approach to analyze liquid samples. The device was equipped with a nanoelectrospray ionization source. To avoid memory effects, a disposable micropipette was used. An aluminum-coated tip with an ID of 2 μm was applied with a high voltage to achieve nanoelectrospray ionization without sheath gas. Advantages of PFDMA are to isomer separation and better sensitivity compared to other types of ion mobility spectrometers. Most illicit drugs could be detected by this homemade device. The detection limit is lower than the level allowed by law. With our device, the detection limit of methamphetamine is ∼10 ng/ml.

Online analysis of chemical composition and size distribution of fresh cigarette smoke emitted from a heated tobacco product

Online analysis of chemical composition of cigarette smoke of a heated tobacco product (HTP) was performed by using a home-made vacuum ultraviolet (VUV) lamp-based photoionization time-of-flight (TOF) mass spectrometer. A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke, without dilution and pretreatment, which can be switched from each other within minutes. A thermal desorption unit was installed to vaporize the particulate-phase into gas and its vaporization temperature was determined, based on an equilibrium between the evaporation efficiency and the thermal decomposition of organic compounds. Then these species were softly ionized by VUV photons and their ions were measured by a reflectron TOF mass analyzer. Meanwhile, the puff-by-puff resolved size distributions of the HTP smoke were probed with a commercial scanning mobility particle sizers (SMPS). The mean diameters of particles firstly increase with the puff number, mainly located in the range of 200 – 300 nm, and then approached a steady state. This method was validated to measure the physical-chemical characteristics of the HTP cigarette smoke.•A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke.•Chemical composition of the HTP smoke was measured by using a compact VUV photoionization mass spectrometer.•The particle size distribution of the HTP smoke without dilution was measured online.

Simulation of private and commercial e-mobility charging behaviour to reassess coincidence factors for distribution grid planning

The coincidence factor is an important element in grid planning as it describes the maximum simultaneous load that can occur in a defined grid segment. Due to the highly stochastic nature of electric vehicle trips (defined by their start time/location and arrival time/destination), it is a challenge to determine reliable coincidence factors for charging profiles with representative data. Since real measurements are not yet sufficiently present, given the low penetration level of electromobility, this paper proposes two stochastic models to simulate the representative mobility behaviour of private and commercial electric vehicles. In our models, we consider large public databases containing mobility behaviour of individual private drivers and commercial vehicles, including surveys and customized stochastic processing. The models provide a simulation of realistic mobility profiles and the extraction respective charging schedules. In a final step, we superimpose the set of resulting load profiles to obtain the desired coincidence factor. We have shown in the results that the models can realistically replicate private and commercial mobility. The resulting coincidence factors show differences depending on the settlement structure. Metropolitan regions, in particular, show a lower coincidence factor compared to other areas.

Characterization of vapor emissions from pentaerythritol tetranitrate solids in nitrogen by atmospheric pressure chemical ionization mass spectrometry and in ambient air by ion mobility spectrometry

ABSTRACT The emission of vapors from solid samples of Pentaerythritol Tetranitrate (PETN) in a flow of nitrogen from ~20 to 140°C was characterized using atmospheric pressure chemical ionization mass spectrometry equipped with a 63Ni ion source. Mass analysis of ions derived from vapors from military grade PETN at room temperature, without deposition from solution, included only NO3 − (62 Da) and HNO3 ·NO3 − (125 Da) and were attributed to residual levels of nitric acid in the PETN solid. The vapor level of HNO3 persisted until 80°C and after this declined asymptotically to background levels; ions observed above 110°C were nitrate adducts of molecular PETN including (PETN)n ·NO3 − with mass values of 378 Da (n = 1) and 695 Da (n = 2). Subsequent reheating of the PETN solid caused an increase release of nitric acid and formation, above 140°C, of the same nitrate adducts of PETN,, consistent with thermal degradation of some PETN to nitric acid. A commercial handheld ion mobility spectrometer was used to sample airborne vapors from solid PETN in an open container and heated in ambient air. The ion mobility spectra showed that ionization chemistry was rapidly transformed from O2 − to NO3 − which persisted indefinitely and produced ion above 80°C with Ko values of 1.48, 1.21, 1.15, and 1.10 cm2/V s. These relatively low-mobility peaks were attributed to cluster ions of nitrate with nitric acid and molecular PETN generated from thermal decomposition and some vaporization of solid PETN. Persistence of nitrate as a reactant ion in the handheld analyzer suggested a need for specialized designs and materials for such explosives vapor measurements.

COVID-19 screening using breath-borne volatile organic compounds

Rapid screening of COVID-19 is key to controlling the pandemic. However, current nucleic acid amplification involves lengthy procedures in addition to the discomfort of taking throat/nasal swabs. Here we describe potential breath-borne volatile organic compound (VOC) biomarkers together with machine learning that can be used for point-of-care screening of COVID-19. Using a commercial gas chromatograph-ion mobility spectrometer, higher levels of propanol were detected in the exhaled breath of COVID-19 patients (N = 74) and non-COVID-19 respiratory infections (RI) (N = 30) than those of non-COVID-19 controls (NC)/health care workers (HCW) (N = 87), and backgrounds (N = 87). In contrast, breath-borne acetone was found to be significantly lower for COVID-19 patients than other subjects. Twelve key endogenous VOC species using supervised machine learning models (support vector machines, gradient boosting machines (GBMs), and Random Forests) were shown to exhibit strong capabilities in discriminating COVID-19 from (HCW + NC) and RI with a precision ranging from 91% to 100%. GBM and Random Forests models can also discriminate RI patients from healthy subjects with a precision of 100%. In addition, the developed models using breath-borne VOCs could also detect a confirmed COVID-19 patient but with a false negative throat swab polymerase chain reaction test. It takes 10 min to allow an entire breath test to finish, including analysis of the 12 key VOC species. The developed technology provides a novel concept for non-invasive rapid point-of-care-test screening for COVID-19 in various scenarios.

Colonial management as a social field: The Palestinian remaking of Israel’s system of spatial control

This article delves into the everyday dynamics of colonial rule to outline a novel way of understanding colonized–colonizer interactions. It conceives colonial management as a social field in which both the colonized and colonizers negotiate and exchange resources, despite their decidedly unequal positions within a racial hierarchy. Drawing their example from the West Bank, the authors argue that a Palestinian economic elite has proactively participated in the co-production of the colonial management of spatial mobility, a central component of Israeli colonial rule. The study employs interviews and document analysis to investigate how the nexus between Palestine’s commercial-logistical needs and Israel’s security complex induced large-scale Palestinian producers to exert agency and reorder commercial mobility. The authors describe and explain the evolution of a ‘Door-to-Door’ logistical arrangement, in which large-scale Palestinian traders participate in extending Israeli’s system of spatial control in exchange for facilitating logistical mobility. This horizontal social encounter that entails pay-offs is conditioned, but not fully determined, by vertical relations of domination and subordination.