Academic literature on the topic 'MW-LIBS'

There is a lack of information on (i) the potential fire load of new green-technology vehicles, (ii) flame spread behavior, (iii) thermal impacts on high-pressure hydrogen storage vessels (HSVs) and lithium-ion batteries (LIBs) during fuel cell electric vehicles fires (FCEVs), and (iv) thermal damage to adjacent vehicles and upper structural members during FCEV fires occurring in civil structures, such as underground spaces, multi-story parks, and tunnels. In view of this, a full-scale fire test was conducted in this study to quantitatively assess the fire risk of hydrogen FCEVs. Large-scale cone calorimetry was used to quantify the thermal intensity released from the FCEV fire. The flame spreading behavior through an FCEV with HSVs and LIBs was observed using the thermocouples installed. Changes in the temperature and irradiance around the FCEV fire were also measured using an instrumented test rig. The peak heat release rate, total heat released, and fire growth rate were observed to be 5.99 MW, 11.8 GJ, and 0.0055 kW/s², respectively. The temporal point of hydrogen gas release from the HSVs' thermal pressure relief device (TPRD) was estimated to be 16.2-26.2 min. The initiation of thermal runaway of LIBs was deduced from the temperature-time profiles of the LIB modules and their metal housing approximately 22.2 min after HCEV ignition. Moreover, FCEV fires could thermally impair adjacent upper structural members by 800 ℃ combustion gas for at least 13 min and emit a median heat flux of 27.2 kW/m² (peak heat flux of 76.5 kW/m²) to adjacent vehicles. The measurements and findings obtained from this study can contribute to the evaluation of and further studies on newly emerging fire hazards.

The electrolyte is one of the components that releases the most heat during the thermal runaway (TR) and combustion process of lithium-ion batteries (LIBs). Therefore, the thermal hazard of the electrolyte has a significant impact on the safety of LIBs. In this paper, the combustion characteristics of the electrolyte such as parameters of heat release rate (HRR), mass loss rate (MLR) and total heat release (THR) have been investigated and analyzed. In order to meet the current demand of plateau sections with low-pressure and low-oxygen areas on LIBs, an electrolyte with the most commonly used lithium salts, LiPF6, was chosen as the experimental sample. Due to the superior low-temperature performance, an electrolyte containing LiBF4 was also selected to be compared with the LiPF6 sample. Combustion experiments were conducted for electrolyte pool fire under various altitudes. According to the experimental results, both the average and peak values of MLR in the stable combustion stage of the electrolyte pool fire had positive exponential relations with the atmospheric pressure. At the relatively higher altitude, there was less THR, and the average and peak values of HRR decreased significantly, while the combustion duration increased remarkably when compared with that at the lower altitude. The average HRR of the electrolyte with LiBF4 was obviously lower than that of solution containing LiPF6 under low atmospheric pressure, which was slightly higher for LiBF4 electrolyte at standard atmospheric pressure. Because of the low molecular weight (MW) of LiBF4, the THR of the corresponding electrolyte was larger, so the addition of LiBF4 could not effectively improve the safety of the electrolyte. Moreover, the decrease of pressure tended to increase the production of harmful hydrogen fluoride (HF) gas.

A copper helical coil antenna was developed, characterized, and optimized for 2.45 GHz operations supplied by a microwave semiconductor oscillator. The application field of interest is laser-induced breakdown spectroscopy enhanced by microwave. Simulations using the Ansys HFSS demonstrate the superior localized E-field strength of the helical coil antenna, compared with other antenna-type structures. Simulation results show that E-field strength at the tip of the antenna has a logarithmic trend for increasing the coil pitch. The optimum pitch is 5 mm for a coil diameter of 6.5 mm upon consideration of the system compactness. Despite the antenna’s open-circuit end, the presence of target samples does not interfere with the E-field and H-field distribution of the antenna and the surrounding environment. Applications in microwave-enhanced laser-induced breakdown spectroscopy (MWLIBS) confirm the importance of the antenna reflector. The electric field strength was over 100 times higher than the previous capacitor-like antenna. The antenna configuration angle was then experimentally optimized for maximum enhancement effects in the spectrochemical analysis of Al2O3. The antenna angle of 60° from the laser beam propagation achieved maximum enhancement in the emission signal of Al I.

Laser-Induced Breakdown Spectroscopy (LIBS) has been documented as an Atomic Emission Spectroscopy (AES) technique, utilising laser-induced plasma, in order to analyse elements in materials (gases, liquids and solid). The Nd:YAG laser passively Q-switched at 1064nm and 9ns pulse duration focused by convex lens with focal length 100 mm to generates power density 5.5×1012 Mw/mm2 with optical spectrum in the range 320-740 nm. Four soil samples were brought from different northern region of Iraq, northern region (Beiji, Sherkat, Serjnar and Zerkary).The soil of the Northern region of Beige, Sherkat, Serjnar and Zarkary has abundant ratios of the elements P [0.08, 0.09, 0.18, 0.18] and Ca [0.61, 0.15, 0.92, 0.92] while it lack of Si [0.008, 0.004, 0.04, 0.02] element. The data analysis for these soils showed that the cities of Serjnar and Zarkary have soils better than of Sherkat. It is noticed from the obtained P [0.18], and Ca [0.92] elements concentrations of the soil that the cities of Serjnar and Zarkary have the best soil for cultivation.

Large-scale electric-energy-storage (EES) systems have the potential to transform the electric grid. The deployment of recent EES systems have predominately been Li-ion batteries (LiBs), which are being used primarily for Ancillary Services (e.g., frequency regulation) and other grid applications (e.g., load following) that require relatively short discharge durations (i.e., ≤ 4-h at rated power). At these relatively low energy/power ratios, LiBs can be lower cost than the historical EES baseline, which is pumped-storage hydropower (PSH). However, since the cost of most conventional batteries scales linearly with energy capacity, the energy-storage cost ($/kWh) is not necessarily lower for uses that require longer discharge times. For these long-duration energy-storage (LDES) applications (i.e., ≥ 5-h at rated power), EES systems with independent power and energy components, e.g., PSH, redox flow batteries (RFBs), reversible fuel cells, and electrofuels, have an inherent cost advantage, since one can readily increase the energy/power ratio by selectively adding more energy capacity, without the added cost of excessive power components. LDES applications have the potential to be a substantially larger market than short-duration EES; however, the requirements for LDES systems are also inherently more challenging. The primary commercialization challenge is capital cost (i.e., $/kWh installed). In addition to fully decoupled power and energy, RFBs have other unique attributes that make this battery architecture ideally suited for grid-scale LDES, namely: long cycle life even with deep cycles, inherently superior safety, and easy recyclability. Largo Clean Energy (LCE) is a vertically-integrated developer of all-V RFBs (VRFBs), and LCE’s MW-scale product is arguably the most advanced RFB system available on the market today. This talk will primarily focus on: 1) what LCE has already done to substantially reduce the cost of VRFBs, 2) how VRFBs can potentially enable the commercialization of other types of RFB systems, and 3) future opportunities to further reduce the capital cost of a variety of RFB systems. Acknowledgements Many thanks to my flow-battery collaborators at Largo Clean Energy and at Raytheon Technologies Research Center (formerly known as UTRC), as well as many other outstanding colleagues on multiple UTRC-led ARPA-E projects and JCESR collaborations on flow batteries.

Abstract Aqueous ruthenium was detected in real-time at ambient condition using Microwave-assisted Laser Induced Breakdown Spectroscopy (MW-LIBS). A 10mJ laser energy and 750W microwave power were directed at an open liquid jet sample of ruthenium. It was observed, for liquid flow, the coupling efficiency between the microwave and the laser-induced plasma was limited to 43%. The ruthenium’s signal-to-noise ratio improvement for MW-LIBS, with respect to LIBS, was 76-fold. Based on MW-LIBS, the limit of detection (LoD) for Aqueous ruthenium was determined to be 957±84 ppb.

In phase-selective laser-induced breakdown spectroscopy (PS-LIBS), gas-borne nanoparticles are irradiated with laser pulses (∼2.4 GW/cm2) resulting in breakdown of the nanoparticle phase but not the surrounding gas phase. In this work, the effect of excitation laser-pulse duration and energy on the intensity and duration of TiO2–nanoparticle PS-LIBS emission signal is investigated. Laser pulses from a frequency-doubled neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (532 nm) are stretched from 8 ns (full width at half maximum, FWHM) up to ∼30 ns at fixed pulse energy using combinations of two optical cavities. The intensity of the titanium atomic emissions at around 500 nm wavelength increases by ∼60%, with the stretched pulse and emissions at around 482 nm, attributed to TiO, enhanced over 10 times. While the atomic emissions rise with the stretched laser pulse and decay around 20 ns after the end of the laser pulse, the TiO emissions reach their peak intensity at about 20 ns later and last longer. At low laser energy (i.e., 1 mJ/pulse, or 80 MW/cm2), the TiO emissions dominate, but their increase with laser energy is lower compared to the atomic emissions. The origin of the 482 nm emission is explored by examining several different aerosol setups, including Ti–O, Ti–N, and Ti–O–N from a spark particle generator and Ti–O–N–C–H aerosol from flame synthesis. The 482 nm emissions are attributed to electronically excited TiO, likely resulting from the reaction of excited titanium atoms with surrounding oxidizing (carbonaceous and/or radical) species. The effects of pulse length are attributed to the shift of absorption from the initial interaction with the particle to the prolonged interaction with the plasma through inverse bremsstrahlung.

Real time, in-situ quantitative detection of the metals is important for many applications such as industrial processes for the quality control, mining for the quick scan of rocks samples, monitoring of the heavy metal contaminations for the pollution control and realtime analysis of the agriculture land for nutrients monitoring and fertilizer selection. Laser Induced Breakdown spectroscopy (LIBS) being able to offer quick response and multielemental analysis without sample preparation, can meet these requirements. As most of the mentioned applications involve detections of the trace metallic elements, thus LI BS is desired to deliver quantitative measurements with high sensitivity and improved limit of detection. Despite of inheriting some excellent features, LIBS suffers a few limitations such as low Signal to Noise Ratio (SNR), weak limit of detection and low sensitivity. Several methods have been suggested in literature to improve the performance of conventional LIBS, which are based on the concept of aiding LIBS by a secondary source of energy. Microwave-assisted laser induced breakdown spectroscopy (MW-LIBS) is one of these improvement methods, which has immense potential to be considered as a reliable analytical technique due to high sensitivity, improved SNR and limit of detection. However, further improvement in the performance of MW-LIBS is desired for the reliable quantitative metal detections at low concentration while offering high sensitivity. This research is amid to investigate ·the improvement of MW-LIBS using two different approaches. This first is to improve the plasma emission detection by single elemental imaging and the second is to improve the microwave injection by a well-designed near field applicator (NFA). Indium in solid matrix was used to investigate the improvement in emission detection by single elemental imaging. A narrow bandpass filter was used to select the elemental, indium emission at 451.13 nm. This narrow bandpass filter was attached with an ICCD camera to investigate the response of imaging based detection technique at various, laser ar\d microwave powers. Variation in image intensity at several concentrations of indium and evolution of plasma at various microwave powers, was also investigated. Spectral detection was carried out simultaneously with narrow-band imaging to study the extent of improvement in sensitivity. Outcomes demonstrated that imaging technique offers 14-fold improvement in sensitivity following enhancement by microwave radiation, as compared to spectral detection in LIBS with no microwave enhancement. Microwave injection devices such as NFA, being the main component to inject the microwave radiation into the laser ablated plasma, is the most important part of MW-LIBS system, hence defines the performance of the entire MW-LIBS setup. Therefore, having an efficient NFA can considerably improve the signal quality and detection capabilities of MW-LIBS. Considering the importance of an efficient NFA, four designs of NFAs were simulated using the characteristics of available setup, simple isolation techniques such as quarter-wave choke and a finite ground plane were used. These designs were fabricated and tested in the MWLIBS setup for the copper detection in a solid sample. Spectral detections and broadband plasma imaging were carried out simultaneously to investigate the effect of various NFA designs on the signa I quality, size of the plasma and improvement in the detection limit for the existing MW-LIBS setup. From the experimental results, it was concluded that the design D having a finite ground plane of 30 mm diameter performed better than the rest, using this design D a signal enhancement of 849 times was achieved. While 79-fold SNR at 2.6 mJ/pulse laser and 1.2 kWatt microwave power, was observed. By using design D of NFA, ore sample having certified copper concentration of 3.38 ppm was detected with the 166 SNR. The demonstrate high SNR, presents the possibility of detecting sub parts per million in future.
Thesis (MPhil) -- University of Adelaide, School of Chemical Engineering, 2018