Full Charge Research Articles

New class of planar ferroelectric Mott insulators via first-principles design

Inorganic perovskite oxide ferroelectrics have recently generated substantial interest for photovoltaic applications; however, existing materials suffer from excessive electronic band gaps and insufficient electric polarization. The recent resurgence of hybrid perovskite ferroelectrics addresses the aforementioned deficiencies, but they are highly unstable against environmental effects and an inorganic resolution may still be optimal. Here we use first-principles calculations to design a low band gap, planar ferroelectric by leveraging the complexity of layered double perovskite oxides AA$^\prime $BB$^\prime$O$_6$. We exploit A$\ne$A$^\prime$ size mismatch, a nominally empty $d$-shell on the B-site, and A cations bearing lone-pair electrons to achieve a large ferroelectric polarization. Additionally, B$^\prime\ne$B is chosen to achieve full charge transfer and a Mott susceptible filling on the B$^\prime$-site, yielding a low band gap. These principles are illustrated in BaBiCuVO$_6$, BaBiNiVO$_6$, BaLaCuVO$_6$, and PbLaCuVO$_6$, which could be realized in layer-by-layer growth. This new class of materials could lead to stable, high-efficiency photovoltaic.

Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes.

Complexes [{Ru(CO)Cl(PiPr3 )2 }2 (μ-2,5-(CH-CH)2 -(c) C4 H2 E] (E=NR; R=C6 H4 -4-NMe2 (10 a), C6 H4 -4-OMe (10 b), C6 H4 -4-Me (10 c), C6 H5 (10 d), C6 H4 -4-CO2 Et (10 e), C6 H4 -4-NO2 (10 f), C6 H3 -3,5-(CF3 )2 (10 g), CH3 (11); E=O (12), S (13)) are discussed. The solid state structures of four alkynes and two complexes are reported. (Spectro)electrochemical studies show a moderate influence of the nature of the heteroatom and the electron-donating or -withdrawing substituents R in 10 a-g on the electrochemical and spectroscopic properties. The CVs display two consecutive one-electron redox events with ΔE°'=350-495 mV. A linear relationship between ΔE°' and the σp Hammett constant for 10 a-f was found. IR, UV/Vis/NIR and EPR studies for 10(+) -13(+) confirm full charge delocalization over the {Ru}CH-CH-heterocycle-CH-CH{Ru} backbone, classifying them as Class III systems according to the Robin and Day classification. DFT-optimized structures of the neutral complexes agree well with the experimental ones and provide insight into the structural consequences of stepwise oxidations.

철도건설현장 건설기계 재해사례 및 실태분석에 관한 연구

Recently, railroad's preference greatly increased as the environment-friendly means of transportation as the importance in the aspects of environment and energy efficiency. So the government established the Korea Rail Network Authority which takes full charge of railroad construction in 20047 for regular railroad construction to combine major key points in the whole country with each other to be one city region by connecting them to each other to be within the commute time range of a hour and thirty minutes. And it has arranged large-scale railroad construction by establishing plans to build the 1st and 2nd national railroad networks as the national project and investing about 100 trillion won in it from 2006 to 2020. As large-scale railroad construction is promoted as the national project like this, there has been a string of safety accidents in it due to the large and complex construction project. As the government strengthened the safety accident prevention plans, safety accidents have tended to decrease in 2011. However, accidents of construction machinery have found to increase. Therefore, this study tried to investigate accident cases of the Korea Rail Network Authority for the recent 5 years and analyze accidents of construction machinery to prevent them in railroad construction sites and suggest accident prevention plans due to it by conducting, investigating, and analyzing the survey of its operators and superintendents of the construction sites and drawing the problems.

Thermochemistry and Equilibration Time Scales for a Rechargeable Lithium Ion Battery

The open terminal voltage of a lithium ion battery is measured at temperatures ranging from 0°C to 50°C in increments of 10°C. Primary focus is on three states of charge of the battery (full charge, late life, charge depletion). Estimates of the enthalpy, ΔH, and the entropy, ΔS, of the battery reaction are made using the established thermochemical relationship between the open terminal voltage and the Gibbs free energy, ΔG. As expected, ΔS is found to be dependent on the state of charge. The enthalpy also shows some dependence on the state of charge, which is at variance with the ideal Nernstian behavior. This may attributed to non-equivalence of intercalation sites as well as near neighbor interactions. Furthermore, the rate of discharge has little apparent effect on these results. An equilibration time well in excess of 20hours is also observed.

Heteroaggregation of Cerium Oxide Nanoparticles and Nanoparticles of Pyrolyzed Biomass.

Heteroaggregation with indigenous particles is critical to the environmental mobility of engineered nanomaterials (ENM). We studied heteroaggregation of ceria nanoparticles (n-CeO2), as a model for metal oxide ENM, with nanoparticles of pyrogenic carbonaceous material (n-PCM) derived from pecan shell biochar, a model for natural chars and human-made chars used in soil remediation and agriculture. The TEM and STEM images of n-PCM identify both hard and soft particles, both C-rich and C,O,Ca-containing particles (with CaCO3 crystals), both amorphous and "onion-skin" C-rich particles, and traces of nanotubes. Heteroaggregation was evaluated at constant n-CeO2, variable n-PCM concentration by monitoring hydrodynamic diameter by dynamic light scattering and ζ-potential under conditions where n-PCM is "invisible". At pH 5.3, where n-CeO2 and n-PCM are positively and negatively charged, respectively, and each stable to homoaggregation, heteroaggregation is favorable and occurs by a charge neutralization-charge reversal mechanism (CNCR): in this mechanism, primary heteroaggregates that form in the initial stage are stable at low or high n-PCM concentration due to electrostatic repulsion, but unstable at intermediate n-PCM concentration, leading to secondary heteroaggregation. The greatest instability coincides with full charge neutralization. At pH 7.1, where n-CeO2 is neutral and unstable alone, and n-PCM is negative and stable alone, heteroaggregation occurs by a charge-accumulation, core-shell stabilization (CACS) mechanism: n-PCM binds to and forms a negatively charged shell on the neutral surface of the nascent n-CeO2 core, stabilizing the core-shell heteraggregate at a size that decreases with n-PCM concentration. The CNCR and CACS mechanisms give fundamental insight into heteroaggregation between oppositely charged, and between neutral and charged nanoparticles.

Effect of injection pressure on the performance and emission characteristics of CI engine using canola emulsion fuel

ABSTRACTBiodiesel is a promising renewable alternative fuel for diesel. The need of biodiesel fuels for the diesel engines is to restrict the dependency on the fossil fuels in context to the world energy oil crisis. The objective of this article is to investigate the performance and emission characteristics of a CI engine with diesel and blends of canola biodiesel Emulsion at 200, 220 and 240 bar. The fuel injection system in a diesel engine is to achieve a high degree of atomisation for better penetration of fuel in order to utilise the full air charge and to promote the evaporation in a very short time and to achieve higher combustion efficiency. Emulsified fuels showed an improvement in brake thermal efficiency of 28.8% at 240 bar accompanied by the drastic reduction in NOx at 200 bar.

A 3D diamond detector for particle tracking

In the present study, results towards the development of a 3D diamond sensor are presented. Conductive channels are produced inside the sensor bulk using a femtosecond laser. This electrode geometry allows full charge collection even for low quality diamond sensors. Results from testbeam show that charge is collected by these electrodes. In order to understand the channel growth parameters, with the goal of producing low resistivity channels, the conductive channels produced with a different laser setup are evaluated by Raman spectroscopy.

3D cylindrical silicon microdosimeters: fabrication, simulation and charge collection study

This paper reports on the fabrication, simulation, and charge collection characteristics of a new generation of cylindrical silicon microdosimeters fabricated on SOI wafers. The devices consist of an array of p+ electrodes surrounded by trench n+ electrodes creating well defined, cylindrical sensitive volumes. A first batch of microsensors with 5.4 μm active thickness has been successfully fabricated. The devices are fully functional with good diode behavior and a depletion voltage of only 3 V. Their charge collection characteristics have been investigated using the IBIC technique with protons and alpha particles. The IBIC maps show a 100% yield of active cells in a microdosimeter array and full charge collection efficiency in the active area of the unit microsensors. These devices constitute an step forward in the current status of microdosimeters based on silicon technologies.

ALPIDE, the Monolithic Active Pixel Sensor for the ALICE ITS upgrade

A new 10m2 inner tracking system based on seven concentric layers of Monolithic Active Pixel Sensors will be installed in the ALICE experiment during the second long shutdown of LHC in 2019–2020. The monolithic pixel sensors will be fabricated in the 180nm CMOS Imaging Sensor process of TowerJazz. The ALPIDE design takes full advantage of a particular process feature, the deep p-well, which allows for full CMOS circuitry within the pixel matrix, while at the same time retaining the full charge collection efficiency. Together with the small feature size and the availability of six metal layers, this allowed a continuously active low-power front-end to be placed into each pixel and an in-matrix sparsification circuit to be used that sends only the addresses of hit pixels to the periphery. This approach led to a power consumption of less than 40mWcm−2, a spatial resolution of around 5μm, a peaking time of around 2μs, while being radiation hard to some 10131MeVneq/cm2, fulfilling or exceeding the ALICE requirements.Over the last years of R & D, several prototype circuits have been used to verify radiation hardness, and to optimize pixel geometry and in-pixel front-end circuitry. The positive results led to a submission of full-scale (3cm×1.5cm) sensor prototypes in 2014. They are being characterized in a comprehensive campaign that also involves several irradiation and beam tests. A summary of the results obtained and prospects towards the final sensor to instrument the ALICE Inner Tracking System are given.

Reaction and Mass Transport Simulation of 3-Dimensional All-Solid-State Lithium-Ion Batteries for the Optimum Structural Design

In order to increase energy density and enhance safety, all-solid-state lithium-ion battery has been developed as a storage battery for electric vehicles. However, its power density is too low to be applied for EV. In recent years, 3-dimensional electrode such as an interdigitated electrode is proposed, which can increase both energy density and power density. In this study, electrochemical reactions and mass transport phenomena of 3D all-solid-state battery were simulated with a porous electrode theory. Discharge property was improved by complicating 3D structures and Str. 2 displayed excellent discharge property at a rate of 1 to 10C and a solid electrolytes ionic conductivity of 0.01 to 1 S/m. Furthermore, the structure of which diffusion length is shorter than 36.57 μm can realize the full charge within 6 minutes at more than 1 S/m, and the diffusion length within 8 μm is necessary at 0.01 S/m to 1 S/m.

Alternative Solar-Battery Charge Controller to Improve System Efficiency

When the heat losses sense is adopted for some solar system and power conversion components in residential building application, it is benefit to use those losses, that are consequently acts inversely on system efficiency, as a useful energy to modify the performance of that system instead of dissipated. In terms of efficiency of solar-battery charge controller, power dissipation is always associated with every power component and the losses would be either results from switching and conducting components or from the OFF state of the main switching component. This paper proposed a high efficiency solar-battery charge controller as an alternative to the main solar charge controller in most conventional residential solar system , the concept of the proposed controller circuit based on using the off state energy duration as well as that power losses coming from the main switching component and complexity of the conventional controller, and using this energy in a separate current path to energize an auxiliary battery or directly load used to cool or even to ventilate the system components causing in improving its performance. This will leads to electronic circuit with low losses as a compared with the conventional charge controller to be a part of the integrated and automated building solar system, the design has an algorithm based on some environment parameters like sun Irradiance and weather temperature, this algorithm seems to be inversely calculated because its start from the value of full charge battery voltage. A Simulink Matlab simulator is attempted in the simulation phase of this research as well as an experimental data has been collected to verify the circuit function and energy saving goal.

Three-dimensional graphite electrodes in CVD single crystal diamond detectors: Charge collection dependence on impinging β-particles geometry

The charge collection performance of a three-dimensional diamond-graphite detector is reported. Buried graphite pillars with high aspect ratio were formed inside a single crystal synthetic diamond slab by using a femtosecond IR laser with 200kHz of repetition rate. Grouped in two series and connected by graphite strips on the surface, eight independent 3D electrodes were used to collect the charge carriers generated by energy deposited in the detector by 90Sr,Y β-particles. Different impinging configurations were used to test charge collection and signal dependence on voltage. Reversing the bias polarity the pulse height distribution does not changes and the charge collection saturation of any group of connected pillars was observed around ±80V (0.53V/μm). The average charge collected by one pillars row is Qav=1.60±0.02fC, with electrons impinging orthogonally the rows, in such a way demonstrating full charge collection.

Full weak-charge density distribution ofCa48from parity-violating electron scattering

Background: The ground state neutron density of a medium mass nucleus contains fundamental nuclear structure information and is at present relatively poorly known. Purpose: We explore if parity violating elastic electron scattering can provide a feasible and model independent way to determine not just the neutron radius but the full radial shape of the neutron density $\rho_n(r)$ and the weak charge density $\rho_W(r)$ of a nucleus. Methods: We expand the weak charge density of $^{48}$Ca in a model independent Fourier Bessel series and calculate the statistical errors in the individual coefficients that might be obtainable in a model parity violating electron scattering experiment. Results: We find that it is feasible to determine roughly six Fourier Bessel coefficients of the weak charge density of 48Ca within a reasonable amount of beam time. However, it would likely be much harder to determine the full weak density of a significantly heavier nucleus such as 208Pb. Conclusions: Parity violating elastic electron scattering can determine the full weak charge density of a medium mass nucleus in a model independent way. This weak density contains fundamental information on the size, surface thickness, shell oscillations, and saturation density of the neutron distribution in a nucleus. The measured $\rho_W(r)$, combined with the previously known charge density $\rho_{ch}(r)$, will literally provide a detailed textbook picture of where the neutrons and protons are located in an atomic nucleus.

Diagnosis Method to Detect the Incorporation of Metallic Particles in a Lithium Ion Battery

Lithium ion batteries have the issue of internal short circuiting by the electrodeposition of metal at the negative electrode. This deposition follows the dissolution of metal particles incorporated into the positive electrode in manufacturing process. Thus, we have investigated the dissolution-deposition behavior of metals such as iron and copper using cyclic voltammetry and SEM/EDX. We have also addressed diagnosis method for the incorporation of the metal particles by electrochemical impedance spectroscopy. Test cells were assembled with positive electrodes of LiCoO2 mixed with acetylene black as conductive filler and PVDF binder, electrolyte solution of ethylene carbonate (EC)/diethylcarbonate (DEC) (1:1 vol.) containing 1 M LiPF6, and negative electrodes of graphite mixed with PVDF binder. Lithium metal was used as a reference electrode. Cyclic voltammetry was carried out with positive electrodes of iron plate and copper foil as working electrodes. Current onset potentials originating in the anodic dissolution of iron and copper were around 2.4 V and 3.6 V (vs. Li+/Li), respectively[1]. Hence those metal dissolve during charging of a cell. The anodic current for copper was larger than that for iron． Iron particle with a diameter of 150 μm, and copper particle with a diameter of 100 μm were adhered to the positive electrode surface. The fully charged cell by 1C with the iron particle exhibited no rapid voltage drop for one week whereas the cell with the copper particle showed rapid voltage drop before full charge, resulting in the short circuit much earlier than iron in agreement with the larger anodic dissolution current shown by the cyclic voltammetry. SEM and EDX observations of the surface of the negative electrode after charging showed iron and copper depositions in torus-shape. We also repeatedly maintained the cells with those metal particles under fully charged state (SOC:100%) for 24 hours before a discharging/charging cycle to assess the time variation of impedance spectra. As a result, we find characteristic change of the Bode plot for the negative electrode in the case of iron particles between 10-1 Hz as shown in Fig. 1. Since time variation in the impedance spectra was detected, electrochemical impedance spectroscopy is effective diagnosis method to detect the metal particle incorporation. [1] C. Iwakura, Y. Fukumoto, H. Inoue, S. Ohashi, S. Kobayashi, H. Tada, and M. Abe, J. Power Sources, 68, pp. 301-303 (1997). Fig. 1 Bode plots for the negative electrode (a) with and (b) without the Fe particles. Figure 1

Characterization of the charge‐carrier transport properties of IIa‐Tech SC diamond for radiation detection applications

Single crystal (SC) diamond has since years demonstrated its interest for the fabrication of radiation detectors, especially where the material properties are providing superior interests with respect to the detection application. Among the industrial suppliers able to provide on a commercial basis high‐grade single crystal diamond, IIa‐Tech has recently appeared in the market as a new player. The aim of this paper is to assess the quality of one SC sample when characterized under α‐particles for the measurement of its carrier transport properties. We observed that full charge collection could be observed at biases as low as 0.11 V/μm with no space charge build‐up (conventionally typical bias values used are closer to 1 V/μm). Velocity reached values of 38 μm/ns and 53 μm/ns for electrons and holes, respectively (values probed at 0.33 V/μm). Similarly, the α detection spectrum displays a sharp line demonstrating the good uniformity of the material over its surface. By combining the measurements with more conventional optical observations such as birefringence and cathodoluminescence spectroscopy, it comes that the material demonstrates its ability to be used as a detector, with properties that can compare with the highest grade materials today available on the market.

Modeling and characterization of electret based vibration energy harvesters in slot-effect configuration

The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power.

Monte Carlo simulations of water solubility in ionic liquids: A force field assessment

Gibbs ensemble Monte Carlo simulations were used to calculate absorption isotherms of water in three imidazolium-based ionic liquids (ILs) with different degrees of hydrophobicity: 1-n-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]), 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C4mim][Tf2N]) and 1-n-butyl-3-methylimidazolium chloride ([C4mim][Cl]). An evaluation of several water models and various IL force fields was conducted. The selected water models are the TIP5P, TIP4P2005 and a collection of three site models based on the SPC geometry but with different sets of fixed partial charges. These partial charges are consistent with water surrounded by different electrostatic environments, and crudely account for polarizability. In the case of the IL force fields, net partial charges of ±1.0e were used. In addition, scaled charges of ±0.9e and ±0.8e were used to account for polarization and charge transfer. It is found that most water models tested with the full charge [C4mim][PF6] and [C4mim][Cl] force field overestimate the solubility, but the agreement is reasonably good with [C4mim][Tf2N]. Attempts at improving the results by either scaling the charges on the IL or on water were made, but no combination was able to reproduce experimental phase behavior satisfactorily. The main conclusion of the study is that, to consistently model water absorption in ILs, force fields that include effects such as polarization are likely necessary.

Varying Charges and Questionable Costs.

Varying Charges and Questionable Costs.

Aging formula for lithium ion batteries with solid electrolyte interphase layer growth

Hybrid Electric Vehicle (HEV) current profiles are dynamic, consisting of repeated charge and discharge pulses. Accurate prediction of the battery response to these inputs requires models with open circuit voltage and Butler–Volmer kinetic nonlinearities. This paper derives a nonlinear, electrolyte-enhanced, single particle model (NESPM) that includes aging due to solid electrolyte interphase layer growth. The model is validated with experimental full charge, discharge, HEV cycle, and aging data from 4.5 Ah graphite/LiFePO4 cells. The NESPM is capable of operating up to 3C constant charge–discharge cycles and up to 25C and 10 s charge–discharge pulses within 35–65% state of charge (SOC) with less than 2% error. The NESPM aging model is then simplified to obtain explicit formulas for capacity fade and impedance rise that depend on the battery parameters and current input history. The formulas show that aging increases with SOC, operating temperature, time, and root mean square (RMS) current. The formula predicts that HEV current profiles with the (i) same average SOC, (ii) small SOC swing, (iii) same operating temperature, (iv) same cycle length, and (v) same RMS current, will have the same cell capacity fade.

Impacts of Room Temperature on the Performance of a Portable Propane Air Conditioner

The performance of a portable propane air conditioner system, in which the temperatures of the air passing over the condenser and evaporator are equal, has been experimentally investigated under different room temperatures and refrigerant charge levels. The research has been carried out in a range of room temperatures from 20°C to 35°C and in undercharge, standard charge and overcharge conditions. The results show that, at higher room temperatures, the refrigerant temperature in all parts of the system, the density of the refrigerant at the inlet and outlet of the condenser, mass of the refrigerant in the compressor, the mass flow rate of the refrigerant and the cooling capacity of the system in either the undercharge or full charge condition, the specific cooling capacity of the undercharge system, the useful work of the compressor, and the maximum pressure of the refrigerant increase. The increase in room temperature decreases the density of the refrigerant at the inlet and outlet of the capillary tube, the mass of the refrigerant in the capillary tube, the refrigerant subcooling at the inlet of the capillary tube, the maximum velocity of the refrigerant and the coefficient of performance. In addition, the increase in room temperature at overcharge condition causes an increase in the mass flow rate, cooling capacity and specific cooling capacity to a maximum value followed by their decrease. The most important difference between a portable air conditioner and a nonportable system is the increase in cooling capacity with an increase in room temperature in full charge condition.