FuelCell2008-65064 MODELING AND CONTROLS OF A FUEL DELIVERY SYSTEM WITH DUAL RECIRCULATION LINES FOR A PEM FUEL CELLSYSTEM

ABSTRACT A fuel delivery system with dual recirculation lines is investigated in this paper, which can reuse the exhausted gas from the outlet of anode flow channel. In the automotive application, the fuel delivery system regulates the hydrogen pressure and flow rate from the tank to the anode flow channel that change dynamically with load. The control objectives of fuel cell stack require that a slight pressure difference between the anode and cathode be maintained to prevent the damage of the membrane. In addition, the unconsumed hydrogen is circulated to a supply line by the recirculation lines. The fuel delivery system analyzed in this paper consists of two supply lines and two recirculation lines. The supply line with a low pressure regulator accounts for the supply of fuel at relatively low load demands. The other supply line with a flow controller starts to provide additional fuel with controllable flow rate at high load demands. The recirculation line with an ejector allows for mixing the unconsumed hydrogen with the supplied fuel. The other recirculation line with a blower is used to improve the controllability of the recirculation flow rate. Analysis of the fuel delivery system with dual recirculation lines is carried out by modeling and simulating an integrated system, where the components are modeled involving the dynamic characteristics. The major components of fuel delivery and recirculation system are an ejector, a blower, and a pressure regulator. In addition, the linearization of the integrated system is expressed in the approach of state equations to form the control problem of the system. Then the linear controllers are designed based on the decentralized proportional and integral control, and the state feed-back control. The systems with the different controllers are simulated at different operating points to evaluate their tracking performance by comparing the dynamic response curves. INTRODUCTION Fuel cells are promising technology that is developed to meet future power generation needs The high pressure in the hydrogen tank is regulated into low pressure to supply the stack for meeting power demands. In addition, the unconsumed hydrogen is circulated to a supply line to increase the fuel efficiency [4] and provides a mechanism for water remova

Aminobenzopyranoxanthene based salicylhydrazone probe for colorimetric detection of Cu2+

A new colorimetric probe aminobenzopyranoxanthene salicylhydrazone (ABPX-Sal) has been synthesized by condensation of salicylaldehyde with aminobenzopyranoxanthene hydrazide (ABPX-hy). Owing to its spirohydrazone structure, this probe showed a significant absorption enhancement at 419 ​nm in the presence of Cu2+, and the color changed from colorless to yellow. There was a good linear relationship between the absorption intensity of ABPX-Sal and the amount of Cu2+ (R2 = ​0.9928), and the detection limit was calculated to be 0.912 ​μM. The binding mode between ABPX-Sal and Cu2+ was 1:2, which was proved by ESI-MS. The sensing mechanism was revealed to be a spiro-ring enacted coordination process by DFT calculation. The desired level of selectivity, sensitivity (within 30 ​s), and reusability made this probe very practical in acidic samples

Comparative analysis of the complete chloroplast genomes of Cirsium japonicum from China and Korea

Cirsium japonicum (C. japonicum) is a traditional Chinese medicine belonging to the family Asteraceae. The previous studies have indicated that the chemical compound content of C. japonicum from different places was different. To distinguish C. japonicum from different geographies, the chloroplast genome of C. japonicum from China was sequenced and compared with that from Korea. The total length of this genome is 152,602 bp, similar to that of Korea (152,606 bp). It has a conservative quartile structure which is composed of a large single-copy (LSC) region, a small single-copy (SSC) region and a pair of inverted repeats (IRs) regions, with lengths of 83,487 bp, 18,721 bp, and 25,197 bp, respectively. It encodes 79 protein-coding, 27 transfer RNAs, and 4 ribosomal RNA genes. The overall GC content of the genome is 37.70%. A total of 20 single nucleotide polymorphisms and 6 insertions and deletions were identified between the chloroplast genome of C. japonicum from China and Korea. These results can be applied to develop molecular markers to distinguish C. japonicum from different geographical origins

Effect of process parameters on plasma partial oxidation approach for removal of leaking LPG

In order to address the challenge of preventing explosions in the accidental disposal of leaking liquefied petroleum gas (LPG), a plasma partial oxidation (PPO) approach for converting the gas into liquid products is proposed for the first time, which eliminates the explosion risk in leaking LPG from the pathway of combustible gas removal. The effect of the initial C4H10 (Simulated LPG) concentration, discharge power, and residence time on the reaction performance were investigated, and the main reaction pathway was proposed. The residence time had the greatest effect on C4H10 conversion (27.6 – 78.0%) and yield of total liquid products (26.0 – 63.9%). The rise in discharge power substantially increased the C4H10 conversion (29.9 – 51.2%) and maintained a liquid product selectivity of more than 88.0%. When the initial C4H10 concentration is lower than 5%, the C4H10 concentration can reduce directly to 1.8% at a moderate discharge power (39 W) and residence time (0.81 s), which can eliminate the risk of explosion. This article provides a new approach for the disposal of LPG spills and offers new insights into the effects of main process parameters and their mechanisms for optimizing the PPO reaction performance of converting C4H10 into liquid products

A Highly Efficient Recombinant Laccase from the Yeast <i>Yarrowia lipolytica</i> and Its Application in the Hydrolysis of Biomass

<div><p>A modified thermal asymmetric interlaced polymerase chain reaction was performed to obtain the first yeast laccase gene (YlLac) from the isolated yeast <i>Yarrowia lipolytica</i>. The 1557-bp full-length cDNA of YlLac encoded a mature laccase protein containing 519 amino acids preceded by a signal peptide of 19 amino acids, and the YlLac gene was expressed in the yeast <i>Pichia pastoris</i>. YlLac is a monomeric glycoprotein with a molecular mass of ~55 kDa as determined by polyacrylamide-gel electrophoresis. It showed a higher catalytic efficiency towards 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (<i>k_cat/K_m</i> = 17.5 s^-1 μM^-1) and 2,6-dimethoxyphenol (<i>k_cat/K_m</i> = 16.1 s^-1 μM^-1) than other reported laccases. The standard redox potential of the T1 site of the enzyme was found to be 772 mV. The highest catalytic efficiency of the yeast recombinant laccase, YlLac, makes it a good candidate for industrial applications: it removes phenolic compounds in acid-pretreated woody biomass (<i>Populus balsamifera</i>) and enhanced saccharification.</p></div

AudioGPT: Understanding and Generating Speech, Music, Sound, and Talking Head

Large language models (LLMs) have exhibited remarkable capabilities across a variety of domains and tasks, challenging our understanding of learning and cognition. Despite the recent success, current LLMs are not capable of processing complex audio information or conducting spoken conversations (like Siri or Alexa). In this work, we propose a multi-modal AI system named AudioGPT, which complements LLMs (i.e., ChatGPT) with 1) foundation models to process complex audio information and solve numerous understanding and generation tasks; and 2) the input/output interface (ASR, TTS) to support spoken dialogue. With an increasing demand to evaluate multi-modal LLMs of human intention understanding and cooperation with foundation models, we outline the principles and processes and test AudioGPT in terms of consistency, capability, and robustness. Experimental results demonstrate the capabilities of AudioGPT in solving 16 AI tasks with speech, music, sound, and talking head understanding and generation in multi-round dialogues, which empower humans to create rich and diverse audio content with unprecedented ease. Code can be found in https://github.com/AIGC-Audio/AudioGP

Effect of pH and temperature on YlLac activity.

<p>(a) Effect of pH on the activity of purified YlLac towards ABTS (●), toluidine (▼), guaiacol (Δ), and 2,6-DMP (○). Reactions were at room temperature for 3 min in citrate/acetate/phosphate buffer. (b) Effect of temperature on the activity of purified YlLac assessed by the standard assay method. Activities are expressed as percentages of maximum activity; the error bars do not exceed the dimensions of the symbols.</p

Time course of phenolic content of <i>P</i>. <i>balsamifera</i> prehydrolysate during pretreatment with YlLac at different pHs, (a) 3, (b) 4, (c) 5.

<p>Untreated control (without laccase) is also shown, (d) Reducing sugar production from acid-pretreated <i>P</i>. <i>balsamifera</i> by Celluclast 1.5L: without laccase pretreatment (black bar), and with YlLac pretreatment (gray bar). Error bars indicate standard deviations from mean values.</p

Dependence of the catalytic current on pH for YlLac-coated glassy carbon electrode with ABTS (○) and 2,6-DMP (■), as substrates.

<p>Dependence of the catalytic current on pH for YlLac-coated glassy carbon electrode with ABTS (○) and 2,6-DMP (■), as substrates.</p