88 research outputs found
Evaluation of compounds generated in the thermal hydrolysis process on microbial activities in partial nitritation/anammox process
No full textAnaerobic digestion (AD) is a traditional technique to treat sewage sludge and produce biogas. Thermal hydrolysis process (THP) is a feasible pretreatment for AD by improving the biodegrdability of organic compounds. Partial nitritation/anammox (PN/A) process could be applied in side-stream for treating the reject water from AD since the reject water has a low ratio of COD/N. The prime microorganisms involved in PN/A process are anammox biomass, denitrifiers, ammonium oxidizing organisms (AOO) and nitrite oxidizing organisms (NOO). However, the compounds generated in THP may cause negative effect on microbial activities. In this research, characteristics of the reject water was clarified, and manometric method and respirometry method were used to determine the microbial activities by measuring the conversion rates of the substrates. A higher concentration of soluble COD, total ammonium as nitrogen (TAN) and refractory compounds were in the wastewater treatment plants (WWTPs) with THP installation (i.e. Tilburg, Hengelo, Apeldoorn, and Amersfoort) than the ones in the WWTPs without THP pretreatment (i.e. Sluisjesdijk and Olburgen). Sluisjesdijk has one step PN/A process, while Olburgen has two steps PN/A process. Maximum specific anammox activity(SAA) among the studied WWTPs was found in Sluisjesdijk as 1.32±0.02 gN/gVS/day. THP installation could suppress the SAA value. The presence of refractory compounds may lead to the decrease of SAA. The denitrification activity was enhanced by the high concentration of COD generated in THP. The ratio of AOO activity to anammox activity were similar to the stoichiometry value of 1.32 in Sluisjesdijk Sharon reactor, Tilburg, Hengelo and Amersfoort. Molecular methods may recommended for further study in the area of this research
Essays on Bank Liquidity Provision
No full textThis dissertation consists of three chapters that examine how banks transmit monetary policy and react to the ambiguity via liquidity provision.
Chapter 1: This chapter analyzes both market conditions and bank balance sheets separately, and use these analyses to extend the Liquidity Mismatch Index (LMI)(Journal of Finance, 2017) so as to provide a granular, bank specific measure that covers the period from 2002 to 2025. My findings indicate that since the financial crisis, the banking system has increased its holdings of cash (primarily through interest-bearing balances), securities (with increasing HTM securities), and loans. However, when incorporating market dynamics, I observe that short-term assets have gained a higher weight in the total asset-side liquidity over time. Consequently, banks’ assets have become increasingly liquid. On the liability side, the banking system has increased its holdings of uninsured deposits, a consequence I study in my work on unconventional monetary policy such as quantitative easing (QE). Simultaneously, the demand for liquidity has decreased during this regime. On net, I find that banks create less liquidity during QE periods. I further examine the relationship between bank liquidity creation and non-interest income. My findings indicate that since 2013, banks with higher non-interest income hold more liquid assets and liabilities. In particular, although these banks generate more long-term loans, they simultaneously hold more short-term assets. This balance results in less liquidity creation on the asset side. By creating this unique data series, I study bank liquidity provision in my companion research papers.
Chapter 2: This chapter exploits exogenous liquidity demand shocks in the wake of natural disasters to detect the ongoing role of banks as marginal liquidity providers and as conduits for monetary policy. Using the Liquidity Mismatch Index (Journal of Finance, 2017), we measure the bank’s increase in marginal liquidity during the six months following natural disasters. This liquidity supply initially takes the form of increases in demandable deposits and other liquid liabilities during the focal disaster quarter, and increases in long-term lending during the following quarter, with return to pre-disaster levels in the second quarter following the natural disaster. Banks’ marginal liquidity provision has beneficial effects on local economic conditions, with increases in the growth rate of employment with particular gains in the construction industry. Overall, improvements in local economic conditions last beyond the six-month liquidity provision period and yield local advantages lasting beyond the final quarter of banks’ marginal liquidity provision. Applying these results, we find that banks sluggishly transmit central bank monetary policy via liquidity provision during unconventional monetary policy periods. During periods of quantitative easing, banks’ liquidity responses were smaller and delayed, suggesting that aggressive monetary policies crowd out private bank liquidity provision.
Chapter 3: Long term banking relationships generate private information that allows the bank to offer credit to financially-constrained, informationally-opaque firms at interest rates that include monopoly rents. However, if the bank’s financial condition is ambiguous (exposed to Knightian uncertainty), potential borrowers may exaggerate their subjective perceptions of adverse future outcomes such as bank failure that would interrupt the supply of credit, thereby inducing customers to run to less ambiguous competitor banks. We show that banks mitigate this costly loss in bank monopoly franchise value by creating liquidity at the bank level. Banks create liquidity by utilizing short-term liabilities to fund long term, illiquid loans and other assets. This credibly signals bank relationship customers that the bank has the resources to satisfy future loan demand because the bank can absorb costly liquidity risk exposure. Ambiguity-averse customers are thus less likely to run, thereby retaining their valuable banking relationship and preserving the bank’s monopoly access to private information. We show that ambiguity-linked liquidity provision prevents runs by uninsured deposits. Further, bank customers’ ambiguity and precautionary cash holdings decline when their relationship banks create liquidity. Finally, bank insiders provide more liquidity when their stock options are at or out of the money, and sell shares when the bank’s ambiguity is high
Strain Compensation Constitutive Model and Parameter Optimization for Nb-Contained 316LN
No full textHot deformation behavior of Nb-contained 316LN was investigated using a series of compression tests performed on a Gleeble-1500D simulator at temperature of 950⁻1200 °C and strain rate of 0.01~1 s−1. Based on the strain compensation method, a modified Arrhenius constitutive model considering the comprehensive effects of temperature, strain rate, and strain on flow stress was established, and the accuracy of the proposed model was evaluated by introducing correlation coefficient (R) and average relative error (AARE). The values of R and AARE were calculated as 0.995 and 4.48%, respectively, proving that the modified model has a high accuracy in predicting the flow stress of Nb-contained 316LN. The microstructure evolution and the dynamic recrystallization (DRX) mechanism of the experimental material were explicated by optical microscopy (OM), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). It was found that continuous dynamic recrystallization (CDRX) characterized by subgrain evolution and discontinuous dynamic recrystallization (DDRX) featured by grain boundary nuclei are two main dynamic recrystallization (DRX) mechanisms of Nb-contained 316LN. Furthermore, based on the results of microstructure analyses, optimum parameters were obtained as temperature ranges of 1100~1200 °C and strain rate ranges of 0.01~1 s−1
Establishment and Application of the Void Closure Prediction Model of 316LN
No full textThe presence of voids in the ingot affects the mechanical properties of the final products of the forging process. It is essential to establish a void closure model to predict cavity closure in the forging process to optimize the forging process and improve forging quality. The main purpose of this study is to obtain an accurate prediction model of void closure for 316LN stainless steel. Using the FEM simulation method to study the closure of spherical voids during forging compression of 316LN materials, we can accurately characterize the state of void closure. The void closure ratio K under different deformations at 1,200°C was counted, and the relationship between K and the effective strain was established to obtain the void closure prediction model of 316LN stainless steel. The void closure prediction model is implanted into DEFORM software through the secondary development method to generate the void closure ratio K. In the postprocessing module of DEFORM software, the void closure status of each part during the forming process can be directly observed. Comparing the results of large-scale upsetting experiments and simulation results, the closure error of each part was only 3%, which indicates that the void closure model established in this paper has higher accuracy, which is helpful for the optimization of the forging process and the control of forging quality
Study on Fire Smoke Distribution and Smoke Control in Extra-long Double-hole Tunnel
No full textAbstract：
Construction of tunnels, as one of the main methods to solve physical traffic barriers, However, It vulnerable to the threat of fire during the process of tunnel operation period. In response to such situation, this article explores the smoke distribution of extra-long double-tube tunnel and its impact on evacuation in the event of a fire. This paper take the Jieling tunnel as an example, and applies Accident Tree Analysis (ATA) method combined with Fires Dynamics Simulator (FDS）simulation software to study the changes of harmful factors such as tunnel smoke. According to the research, when a fire occurs in an extra-long double-tube tunnel, It is concluded that people are supposed to be guided to leave via the nearest cross-passages as soon as possible, In the end analysis the roles that air curtains could play in the control of smoke. It is recommended to open the air curtain so that in such condition people away from the cross-passages have enough time to escape
Motivation and achievement in EFL: the power of instructional approach
No full textMaintaining learning motivation and achieving academic success in English language learning remains a challenge for many university students, particularly those with lower proficiency. Conventional teacher-centered classrooms are often characterized by passive learners with limited personalized support. In contrast, blended and artificial intelligence (AI)-assisted learning have emerged as promising alternatives to address motivational and performance challenges in English as a foreign language (EFL) contexts. However, empirical comparisons of these instructional approaches remain limited. Grounded in Self-Determination Theory (SDT) and cognitive constructivism, this study examined the comparative effects of conventional, blended, and AI-blended instructional approaches on Chinese university students’ goal orientation, self-efficacy, instructional support, and English academic achievement. The AI-blended approach integrated tools such as automated writing evaluation (AWE), automated speech recognition (ASR), and the chatbot DouBao to support pre-class learning. A 1.5-year longitudinal within-subject design was employed with 43 first-year EFL students at a Chinese university. Participants experienced all three instructional approaches sequentially, with data collected via motivational questionnaires and achievement tests. Repeated measures analyses, including ANOVA and Friedman tests, were conducted. Results indicated that both blended and AI-blended instruction significantly improved students’ motivation and academic performance relative to conventional instruction. The AI-blended approach produced the most substantial gains in self-efficacy, instructional support, and key language skills such as listening comprehension, translation, and writing. These findings inform ongoing discussions on the integration of AI in EFL pedagogy and provide practical implications for instructional design, teacher preparation, and education policy innovation. The study’s limitations, including the small sample size, limited demographic diversity, and constraints of a within-subject design, should be addressed in future research
A hybrid Gerchberg Saxton-like algorithm for DOE and CGH calculation
No full textThe Gerchberg-Saxton (GS) algorithm is widely used in various disciplines of modern sciences and technologies where phase retrieval is required. However, this legendary algorithm most likely stagnates after a few iterations. Many efforts have been taken to improve this situation. Here we propose to introduce the strategy of gradient descent and weighting technique to the GS algorithm, and demonstrate it using two examples: design of a diffractive optical element (DOE) to achieve off-axis illumination in lithographic tools, and design of a computer generated hologram (CGH) for holographic display. Both numerical simulation and optical experiments are carried out for demonstration. (C) 2016 Elsevier Ltd. All rights reserved
DBA with consideration of energy, delay and BW for community WDM-OFDM PON
No full textPresented in this paper is a dynamic BW allocation based on the energy, delay and BW for the community WDM-and-OFDM-combined passive optical network (COMWOP) architecture. The performances of proposed architecture and algorithm are simulated and evaluated
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