High Charge Levels Research Articles

Electric Vehicle Battery State of Charge and Charging Station Distance Estimation Using IoT

Background: The global transition to green energy and the rapid development of Electric Vehicle (EV) technology, along with falling component costs, have fueled the growing popularity of electric vehicles. To support the widespread adoption of EVs, an efficient and userfriendly charging infrastructure is crucial. Objective: This work aims to propose a comprehensive EV charging system that addresses the rising demand for charging stations, streamlines the charging process, and empowers EV drivers with essential information. The primary focus is on an economical and effective booking system, enabling users to locate nearby charging stations and make informed choices about their charging preferences. Method: We suggest developing a EVs Charging Finder App, serving as a central platform for EV users to find nearby charging stations. The app will provide vital details, including ratings, reviews, available time slots, charging duration estimates, and more. Users can also contribute new charging station data, fostering app growth. Additionally, an alert system will notify users when nearby charging slots become available, enhancing convenience for EV drivers. Results: The EVs Charging Finder App is anticipated to significantly enhance the accessibility and convenience of EV charging. Users can effortlessly locate charging stations, assess quality through reviews and ratings, and plan charging sessions based on real-time availability. The battery voltage of 45.2 V is a critical parameter for monitoring the health and performance of the battery, influencing the accuracy of state of charge (SoC) estimations and potentially impacting the efficiency of the electric vehicle. The 47.7 km driven is a key factor in assessing energy consumption and vehicle efficiency, which can affect the remaining state of charge in the battery. The battery's state of charge (SOC) is at 85%, indicating a relatively high charge level. Knowing that the charging station is available is crucial for planning charging activities, allowing users to proceed without concerns about station availability. The booking time at 10:00 AM is essential for efficiently managing charging infrastructure, especially in scenarios with high demand for charging services. These data points collectively contribute to optimizing the charging experience and ensuring the effective utilization of electric vehicle resources. Conclusion: The proposed EVs Charging Finder App offers a practical and efficient solution to address the surging demand for charging stations. By providing comprehensive information and real-time alerts, this system aims to make EV charging more accessible, user-friendly, and environmentally sustainable.

Experimental investigation of cooling performance of a CO2 heat pump system with an integrated accumulator heat exchanger for electric vehicles: Impact of refrigerant charge and valve opening

The electric vehicle is drawing particular attentions due to the ever-increasing awareness of environmental pollution protection. For the environmental friendly CO2 automotive heat pump system, the investigation of refrigerant charge amount and valve opening on the system and component performance is still limited, especially for a system with an integrated accumulator heat exchanger. In addition, there is still a lack of oil circulation rate investigation on a CO2 vehicle system. In this study, an experimental investigation of refrigerant charge amount and valve opening for system/component performance and oil circulation performance has been systematically conducted for a cooling mode. There exists an optimal refrigerant charge amount corresponding to a maximum value of the system coefficient of performance, with an optimal charge value of 550 g for the electronic expansion valve opening from 30% to 50%, and with 500 g for the opening above 50%. Lifting the refrigerant charge amount from 450 g to 700 g for each valve opening provides a fall of ~35 °C for the discharge temperature and a growth of ~20 bar for the discharge pressure, respectively, and more pronounced at the low valve opening domains. Increasing the valve opening can accelerate the compressor efficiency, but the impact of the refrigerant charge amount may not carefully follow a similar trend. Lifting the refrigerant charge amount can lead to a significant rise in oil circulation rate, especially under high valve opening domains with the exception of 600 g charge level. Under the low refrigerant charge level, the low-pressure accumulator inlet port is the superheated state, and the oil circulation rate tends to be dropped with the increase of valve opening; while under the high charge level with the inlet to be two-phase state, the oil circulation rate curve behaves as a growing trend. This study is beneficial for the engineering community to have a deep understanding on the electric vehicle system thermal management to maintain the vehicle reliability, and provide safety and comfort benefits.

Power Spectra of Constrained Codes With Level-Based Signaling: Overcoming Finite-Length Challenges

In various practical systems, certain data patterns are prone to errors if written or transmitted. In magnetic recording and communication over transmission lines, data patterns causing consecutive transitions that are not sufficiently separated are prone to errors. In Flash memory with two levels per cell, data patterns causing high–low–high charge levels on adjacent cells are prone to errors. Constrained codes are used to eliminate error-prone patterns, and they can also achieve other goals. Recently, we introduced efficient binary symmetric lexicographically-ordered constrained (LOCO) codes and asymmetric LOCO (A-LOCO) codes to increase density in magnetic recording systems and lifetime in Flash systems by eliminating the relevant detrimental patterns. Due to their application, LOCO and A-LOCO codes are associated with level-based signaling. Studying the power spectrum of a random signal with certain properties is principal for any storage or transmission system. It reveals important properties such as the average signal power at DC, the bandwidth of the signal, and whether there are discrete power components at certain frequencies. In this paper, we first modify a framework from the literature in order to introduce a method to derive the power spectrum of a sequence of constrained data associated with level-based signaling. We apply our method to infinitely long sequences satisfying symmetric and asymmetric constraints. Next, we show how to generalize the method such that it works for a stream of finite-length codewords as well, thus demonstrating how to overcome the associated finite-length challenges. We use the generalized method to devise closed forms for the spectra of finite-length LOCO and A-LOCO codes from their transition diagrams. Our LOCO and A-LOCO spectral derivations can be performed for any code length and can be extended to other constrained codes. We plot these power spectra, and discuss various important spectral properties for both LOCO and A-LOCO codes. We also briefly discuss an alternative method for deriving the power spectrum and introduce an idea towards reaching the spectra of self-clocked codes.

Triboelectric Charging and Separation of Fine Powder Mixtures

AbstractFor increasingly finer powders, the material‐specific separation at high loadings is a challenging task, for instance in recycling processes. Here, a combination of triboelectric charging and electrostatic separation was investigated for powder mixtures of talcum and calcite. The dependencies of the triboelectric charge on the mass loading, the gas velocity, and the mixture ratio were investigated. While higher charge levels were achieved with increasing gas velocity, the mass loading had an opposite effect on the net charge. Although bipolar charge distributions were observed within pure materials and mixtures, electrical neutralization did not occur in the mixtures. Therefore, already in a non‐optimized setup, a decent degree of material enrichment (of up to 53 %) was found on the separating electrodes.

Salicylic acid reduces the incidence of Phomopsis longanae Chi infection in harvested longan fruit by affecting the energy status and respiratory metabolism

This study investigated the effects of salicylic acid (SA) on the disease development, respiration rate, energy status, and respiratory metabolism in Phomopsis longanae Chi-inoculated longans. SA treatment reduced the fruit disease index and respiration rate of P. longanae-inoculated longans as compared to the fruit with mere inoculation. SA treatment suppressed the decline of energy charge, decreased the activities of PGI, SDH and CCO, but boosted the G-6-PDH+6-PGDH and NADK activities. Meanwhile, the NAD and NADH contents were decreased, but NADP and NADPH contents were increased. These findings demonstrated that SA could be used to the inhibit disease development in harvested longans because SA treatment helped maintain a high energy charge level, decreased respiration rate and respiratory pathways like EMP-TCA cycle and CCP, but increased PPP respiratory pathway. This study indicated that the SA treatment was a facile and effective way to retard the disease development of postharvest longans.

From Variability and Aging Rate Spread to Quantification of Failure Rates in Lithium-Ion Packs

One of the most important components of an electric vehicle is its energy storage system. Unfortunately, it has also proven to be the most expensive component, which is limiting the vehicle’s performance, for example range or power, for a given cost target. If higher spreads and poorer cell quality can be coped within the system, costs can be lowered by decreasing the number of cells rejected in production. The aim of the research provided is to optimize system topologies for individual applications in order to find suitable cells, avoid oversizing of battery systems and to give forecasts of lifetime and quantifiably failure rates for battery packs build on cell measurements while decreasing cost. On that account a simulation tool chain was developed to incorporate variability and aging rate spreads in the system design process. With the simulation tool battery topologies can be simulated with different varying usage profiles, cell parameter spreads and varying aging rates. Previous analysis on the impact of variations in commercial lithium-ion battery systems on aging, showed the important role of spreads in cell parameters of the batteries. Cell aging is usually simulated with models with parameters determined by accelerated aging tests, usually consisting of large test set with different operating points. Aging due to high temperatures and charge levels and aging due to cycling is combined to assess the capacity after a given usage profile. In order to decrease the impact of measurement errors all aging parameters are determined on the average of multiple cells. Furthermore, in state-of-the-art simulations, variation from cell-to-cell is not considered, although tests showed a heavy influence. As part of our research, a modeling framework was developed which makes it possible to simulate the electrical and thermal behavior of batteries as well as their aging behavior in different configurations. Thereby, the electrical behavior of the battery can be approximated by an electrical equivalent circuit, which is determined by electrochemical impedance spectroscopy, pulse current parameterization, and relaxation measurement. The thermal model receives the heat loss calculated from the electrical simulation and uses it to calculate the temperature distribution within the battery cell and pack. The feedback of the temperature distribution to the electrical model is given by lookup tables of the electrical elements depending on the cell temperature. The layout of the equivalent circuit framework is flexible for different configurations. Thus, it is also possible to adopt a spread of the parameters within the equivalent circuit diagram for individual cells of a simulated pack. For example, initial capacity distributions obtained by end-of-line testing or from literature can be used. In addition, aging rates from aging tests can be assigned to each cell to take variations in aging speed into account. Together with load profiles, usage pattern and lifetime requirements topologies can be simulated multiple times as part of a Monte Carlo simulation with cell properties derived from the aging rate distributions and initial spread distributions. Subsequently the topology needs to be evaluated to verify if the requirements, especially for mandatory lifetime, are met. If the targets cannot be fulfilled, the topology can be changed. For example, another cell might be used, or the target adjusted, and simulations are repeated. A useful instance for example is the assessment of maximum cell variation for a given application as 800 V EVs, to still reach the lifetime expectations. The same cell might be used, but the initial selection for grading and tolerances during production must be stricter. Figure 1

Response of Conductive and PTFE-Coated Polyester Filters to Cold Fly Ash at Different Dust Charge Levels

The present study embodies the response of two different filter media viz. conductive filter media (stainless steel blended with PET fibers) and PTFE-Coated polyester filter media, at four different charge levels (0 kV, 4 kV, 8 kV, and 12 kV) and at a particular dust concentration (50 g/m3) on pulse-jet filtration process performance. The filter media were tested at ISO-11057 standard with conducting 200 pulsing cycles at final measuring phase. Emission values in terms of PM2.5 and PM10 mass concentration and number particle concentration were comparatively lower while using PTFE-coated filter media in comparison with conductive filter media. Downstream emission values largely reduced for both filter media, particularly at high charge level. PTFE-coated filter media exhibit lower residual pressure drop as compared to conductive filter media when measuring the phase of filtration operation, whereas on the contrary D10, D50, and D90 values were found higher for PTFE-coated filter media and higher charge level. Overall, it can be summarized that PTFE-coated media at higher dust charge levels showed better filtration results.

Electrocochleographic Responses Before and After Short-Term Suprathreshold Electrical Stimulation in Human Cochlear Implant Recipients.

To assess changes in electrocochleographic (ECoG) responses following short-term suprathreshold electrical stimulation during cochlear implant (CI) telemetry in CI recipients. Extracochlear ECoG recordings were conducted before and after intraoperative short-term suprathreshold electrical stimulation. Tone bursts at 500, 750, and 1000 Hz as well as clicks were used as acoustic stimuli. Changes of ECoG responses were correlated to calculated maximum electrical charge levels. Fourteen subjects were included. On average, no significant changes of ECoG responses occurred in the earliest postoperative phase; therefore, also following short-term suprathreshold electrical stimulation. However, one subject (S7) showed a decrease of ECoG responses. Neural as well as hair cell components of the ECoG signal were affected. On average, the maximum electrical charge level was 22 nC (range, 15-37 nC). In S7, the maximum electrical charge level was 17 nC. No correlations were found between maximum electrical charge levels and changes of ECoG signals. In a majority of cases, electrophysiological responses to acoustic stimuli remain unchanged in the earliest postoperative phase. However, deterioration of cochlear function occurs in this phase. Neural as well as hair cell components of the ECoG signal are affected. Such deterioration is not associated with unusually high electrical charge levels during CI telemetry. Overall, our results support the notion that an electrical charge applied at levels used in the clinical routine does not have an acute deleterious effect on cochlear function.

Modeling and Feasibility Analysis of Quasi-Dynamic WPT System for EV Applications

In this paper, a new bidirectional wireless power transfer (WPT) charging and discharging concept is analyzed for its feasibility in integration at traffic signals. Classified as quasi-dynamic WPT (QDWPT), a string of coils are proposed to be installed beneath the road surface to provide grid-to-vehicle and vehicle-to-grid (V2G) services to battery electric vehicles (BEVs) while stopped. An experimentally verified lithium-ion battery array and Bidirectional Wireless Power Transfer system are combined to provide a comprehensive simulation under three proposed scenarios. First, four fixed standardized WPT charging levels are evaluated under a Federal Test Procedure-72 city driving profile. Second, a variable charging scenario autonomously adjusts the charging level based on the BEV state of charge. Third, an algorithm is proposed to toggle between charging and discharging based on the BEV psychological and grid retail price to evaluate V2G service viability. For each scenario, a comparison over the maximum driving range per drive cycle and range gained for each consumed kWh is quantified. Moreover, the effect of WPT coil misalignment over the driving performance is investigated and evaluated. This paper concludes that QDWPT at traffic signals is a promising solution to substantially extend the driving range and operating time for city driving especially at high charging levels.

CFD-DEM investigation of particle elutriation with electrostatic effects in gas-solid fluidized beds

Unsuccessful prediction of particle elutriation in fluidized beds is in part due to the negligence of electrostatic effects. In addition, lack of properly designed experiments makes it difficult to quantify the effects of electrostatics on particle elutriation. In this work, the CFD-DEM modeling approach has been used for the first time to investigate particle elutriation in a 2D fluidized bed taking into account electrostatic effects. Model predictions show that electrostatic charges on particles suppress particle elutriation and even eliminate elutriation completely at relatively higher charge levels. The study further shows that electrostatic effects result in the increase of the fluidized bed height and axial velocity of small particles in the free board which ultimately promotes particle elutriation. However, the presence of agglomerates caused by electrostatic attractions is dominant, thus the decrease in the concentration of small particles in the free board suppresses particle elutriation.

Particle charge-size distribution measurement using a differential mobility analyzer and an electrical low pressure impactor

ABSTRACTWe introduce a particle charge-size distribution measurement method using a differential mobility analyzer and an electrical low pressure impactor in tandem configuration. The main advantage of this type of measurement is that it is suitable for a wide range of particle sizes, from approximately 30 nm up to a micrometer, and for high charge levels, which have been problematic for previously used methods. The developed charge measurement method requires information on the particle effective density, and the accuracy of the measurement is dependent on how well the particle effective density is known or estimated. We introduce the measurement and calculation procedures and test these in laboratory conditions. The developed method has been tested using narrow and wide particle size distributions of a known density and well-defined particle charging states. The particles have been produced by the Singly Charged Aerosol Reference (SCAR) and an atomizer and charged with the previously well-characterized ...

A hybrid approach to computing electrostatic forces in fluidized beds of charged particles

In particulate flow devices particles acquire electric charge through triboelectric charging, and resulting electrostatic forces can alter hydrodynamics. To capture this effect, the electrostatic force acting on individual particles in the device should be computed accurately. Electrostatic force is calculated using a hybrid approach consisting of: (1) long‐range contributions from an Eulerian electric field solved using the Poisson equation (2) short‐range contributions calculated using a truncated pairwise sum and (3) a correction to avoid double counting. Euler‐Lagrange simulation of flows incorporating this hybrid approach reveals that bed height oscillations in small fluidized beds of particles with monopolar charge decreases with increasing charge level, which is related to lateral segregation of particles. A ring‐like layer of particles, reported in experimental studies, forms at modestly high charge levels. Beds with equal amounts of positively and negatively charged particles are fluidized in a manner similar to uncharged particles. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2282–2295, 2016

Assessment of parameters of the hybrid drive system in vehicles in urban traffic conditions

Continuously increasing share of the hybrid and electric vehicles in the global automotive market justifies the need for detailed analysis of the operational effectiveness of these drive systems. The aim of the study was to assess the operational conditions of the combustion engines and electric motors in hybrid drive systems – full hybrid – of the motor vehicles in urban traffic conditions. Variety of designs of such drive systems is related to the high voltage batteries used and the way of charging them. The road tests were conducted in Warsaw (urban traffic conditions) by recording the operational parameters of three vehicles and their driving systems. The conditions of operation of the combustion engine and electric motors along with the values of their high voltage battery charge level were related to the test routes. The analysis of the relative shares of engine and motor operation time in the total time of vehicle operation in urban traffic conditions was conducted. The scope of operation of the hybrid drive system utilizing only electric propulsion system was determined. The relations between the operational indexes of the hybrid propulsion (combustion engine and electric motor) in real traffic conditions and the charge level of batteries, current speeds and accelerations were shown.

The effect of air velocity and proximity on the charging of sprays from conventional hydraulic nozzles

Conventional nozzles where hydraulic pressure is used to form the spray, are widely used in agricultural spraying. In many cases they rely on air assistance to efficiently convey the spray droplets to the target. The addition of a further depositing force based on electrostatic charging can significantly improve deposition, particularly on the shaded or hard-to-reach surfaces. The positioning of induction-charging electrodes close to nozzle outlets was investigated. In the laboratory the charging of a conventional flat-fan hydraulic nozzle was investigated. Optimal spacings were found when a high ambient air velocity was used to prevent charged droplets depositing on the electrodes and their insulated mountings. The moving air also dried them continuously, thereby prevented leakage. The results show that a current of 13.9 μA per nozzle was attainable for a spray pressure of 400 kPa with a liquid flow rate of 0.45 l min −1 and droplet spectrum with a 115 μm volume medium diameter (VMD). This is equivalent to a charge-to-mass ratio of 1.85 mC kg −1 . These high currents and high charging levels were achieved by using air velocities > 10 m s −1 . Laboratory tests showed that the spacing between nozzles could be too small, reducing the level of charge per nozzle. A field sprayer was designed with nozzles using a higher flow rate than those investigated in the laboratory. Field tests of the prototype sprayer in a commercial vineyard showed that electrostatic charging improved the deposition of droplets containing a fluorescent tracer by 200 and 500% on the leaf undersides and the rear of grape clusters, respectively. Core findings of the study : • Air velocity is very important when charging spray generated by hydraulic nozzles. • High-air velocity may facilitate charge level of more than 1.8 mC kg −1 for such spraying. • This level is substantially higher than those previously reported for conventional nozzles. • This charging substantially improved deposition on hard-to-reach surfaces in field tests.

Mass and Charge Distribution Analysis in Negative Electrosprays of Large Polyethylene Glycol Chains by Ion Mobility Mass Spectrometry

The mass spectrometric (MS) complexity associated with the quasi-continuous distribution of mass and charge (m, z) of electrosprayed industrial polymers may be moderated by use of ion mobility spectrometry (IMS) and MS in series. However, when the high charge levels typical of polar polymers stretch the gas phase ions into linear configurations, the mobility Z tends to be closely correlated with m/z, and IMS-MS does not yield spectra more readily interpretable than pure MS spectra. Here we note that the usual high charge states observed in the ESI of polyethylene glycol (PEG) arise because the stretched gas phase chain is able to strongly bind solution cations. We weaken this binding and therefore moderate the charge level by electrospraying in negative mode (NESI). This produces exclusively globular gas phase ions. IMS-MS then readily separates into distinct bands the different z-states, enabling an unambiguous assignment of all ions and simplifying the determination of mass distributions fz(m) for each charge state. The measured probability pz(m) that a polymer ion of given mass m will carry z charges spans a surprisingly narrow z range, each mass being present at most in two charge states. PEG ions of a given charge state z become unstable at a critical mass, below which they shed just one elementary charge, evidently by ion evaporation. We argue that NESI-IMS-MS offers significant analytical advantages over alternative methods previously demonstrated, particularly at increasing masses, when individual ion peaks can no longer be discerned.

Aspects on bleaching and tempo-mediated oxidation of wheat straw pulp fractions

This study outlines research concerning wheat straw fines, including their impact on pulp bleachability, their modification by chemical means, and their use as a dry strength enhancer in a paper application. Results show that primary fines constituting about 23% of the whole wheat straw pulp had a large negative impact on pulp bleachability. The differences in response to bleaching were due to the different properties of the fines, i.e. higher kappa number, higher metal ion content, lower brightness, and lower viscosity compared to that of fibers. It was also shown that the fines fraction is more difficult to oxidize and does not reach as high fiber charge levels as that of the other fractions. However, at a dosage of ≥ 3 mmol hypochlorite/g it was possible to prepare nanofibers from wheat straw fines that showed a good strength-enhancing effect in a paper product. The fact that removal of fines from wheat straw pulps by fractionation improves bleachability and also drainage properties at the same time, while simultaneously the fines can be modified and used as a strength enhancer, is very interesting when evaluating the potential of this type of annual plant as a source for production of different paper products.

Accurate measurement of nanoparticle charge, number and size with the ELPI+™ instrument

Nanoparticle characterization is mainly carried out by microscopy techniques and measurements of size and concentration. However to be able to comprehensively understand the behavior of the aerosol, information on particle charge level is critical. Particle charge has a major effect on the coagulation, deposition and transport as well as on the health effects of the particles. While aged aerosols generally are mainly neutral in terms of charge, freshly generated or resuspended particles can have high charge levels that vary depending on the size, material and generation method of the particles. Charging processes for particles are problematic as they are usually both time dependent and material dependent with sudden changes in magnitude. This makes the charge of a particle nearly impossible to predict without detailed studies and direct measurements. ELPI+™ instrument is a completely new aerosol measurement instrument based on the widely used Electrical Low Pressure Impactor (ELPI) technique. ELPI+™ measures particle concentration and size in a wide size range from 6nm to 10μm in real-time. The operation is based on first charging the particles in a corona charger and then size segregating them in a cascade impactor where all impactor stages are electrically insulated. With the ELPI+™ instrument it is possible to measure not only the particle size and concentration in real-time, but also the charge distribution of the particles. As the particle size classification is made with an impactor, the measured particles can be subsequently analyzed if needed with a suitable technique.

Raman spectroelectrochemistry of a single-wall carbon nanotube bundle

Raman microscopy and spectroelectrochemistry with polymer electrolyte gating is developed to study the effect of charging on Raman spectra of individual single-wall carbon nanotubes (SWCNTs) and bundles. The Raman spectra of a small bundle, consisting of well-separated features from a metallic and a semiconducting SWCNT, have been obtained at different electrochemical charging levels. The broad Fano peak of the metallic SWCNT exhibits an appreciable frequency upshift and simultaneous line narrowing when the charging level, either positive or negative, is increased, in agreement with the presence of a Kohn anomaly in metallic SWCNTs. The radial breathing mode of the metallic tube also shows a similar but much weaker dependence on the charging potential. While the G mode frequencies of the semiconducting SWCNT also increase with the increasing charging level, the magnitude of such change is much smaller than in the metallic SWCNT. At high negative charging potentials the G− peak of the semiconducting SWCNT exhibits a larger upshift than its G+ peak, leading to the observation of merging of these two peaks. However, both G+ and G− peaks of the semiconducting SWCNT become broader at high charging levels, which are not predicted from previous theoretical studies.

Short‐term anoxia treatment maintains tissue energy levels and membrane integrity and inhibits browning of harvested litchi fruit

AbstractPericarp browning is the main limitation to the postharvest storage, handling and marketing life of litchi fruit. Pre‐storage treatment with pure N2 gas is potentially effective in reducing skin browning and maintaining eating quality of litchis. To better understand inhibition of pericarp browning by a short period of anoxia, adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels, adenylate energy charge and membrane permeability were investigated. Litchi fruit were exposed to pure N2 gas for 6 h and then kept in closed but vented containers for 6 days in the dark at 25 °C and 95–100% relative humidity. Changes in the mentioned fruit physiology and biochemistry parameters and in browning index were measured. ATP concentration and adenylate energy charge decreased rapidly and membrane permeability (relative leakage) increased gradually during storage. Fruit exposed to N2 gas exhibited higher concentrations of ATP, ADP and AMP and adenylate energy charge levels, and lower levels of browning index and membrane permeability, compared to control (non‐N2‐treated) fruit. Greater differences in ATP and ADP concentrations and adenylate energy charge levels of pericarp tissues between N2‐treated and control fruit were more manifest after 4 and 6 days of storage, in association with significant differences at the 5% level in the pericarp browning index. It is suggested that pre‐storage anoxia treatment maintains membrane integrity of pericarp tissues, with high ATP and ADP concentrations and high adenylate energy charge levels. Thus, the loss of cellular compartmentalization (mixing of enzymes and substrates) that leads to enzymatic browning of litchi fruit pericarp is delayed. Copyright © 2007 Society of Chemical Industry

Characterization of unipolar electrical aerosol chargers—Part II:: Application of comparison criteria to various types of nanoaerosol charging devices

The framework presented in Part I for comparing the performance of electrical aerosol chargers is applied to published data as well as to new measurements with unipolar corona chargers of very different designs in the size range between 10 and 60 nm. Variables include the internal flow conditions, the ion production arrangement, and the type of electrical field in the mixing zone between ions and particles. Comparisons are made in terms of losses of charged particles vs. charging efficiency and/or vs. average charge per particle. It was found that each charger has a characteristic curve of losses vs. charging effectiveness, comprising data points for a broad range of electrical and ion generation conditions. The results further suggest that the high charge levels and low losses can be achieved by a charger design combining short residence times (associated with turbulence) and high ion concentrations. A carefully adjusted sheath flow is somewhat helpful (at the cost of diluting the aerosol), whereas an AC electric field in the mixing zone of ions and particles does not contribute to improving the charge–loss relationship, even under laminar flow conditions. The uniformity of charging conditions for a weakly charged nanoaerosol in a given charger can be characterized without the need to determine n · t -products, from a plot of measured intrinsic average charge vs. intrinsic charging efficiency and comparing with predictions from charging theory.