Biomass gasification for syngas and biochar co-production: Energy application and economic evaluation

Syngas and biochar are two main products from biomass gasification. To facilitate the optimization of the energy efficiency and economic viability of gasification systems, a comprehensive fixed-bed gasification model has been developed to predict the product rate and quality of both biochar and syngas. A coupled transient representative particle and fix-bed model was developed to describe the entire fixed-bed in the flow direction of primary air. A three-region approach has been incorporated into the model, which divided the reactor into three regions in terms of different fluid velocity profiles, i.e. natural convection region, mixed convection region, and forced convection region, respectively. The model could provide accurate predictions against experimental data with a deviation generally smaller than 10%. The model is applicable for efficient analysis of fixed-bed biomass gasification under variable operating conditions, such as equivalence ratio, moisture content of feedstock, and air inlet location. The optimal equivalence ratio was found to be 0.25 for maximizing the economic benefits of the gasification process

Code Generation as a Dual Task of Code Summarization

Code summarization (CS) and code generation (CG) are two crucial tasks in the field of automatic software development. Various neural network-based approaches are proposed to solve these two tasks separately. However, there exists a specific intuitive correlation between CS and CG, which have not been exploited in previous work. In this paper, we apply the relations between two tasks to improve the performance of both tasks. In other words, exploiting the duality between the two tasks, we propose a dual training framework to train the two tasks simultaneously. In this framework, we consider the dualities on probability and attention weights, and design corresponding regularization terms to constrain the duality. We evaluate our approach on two datasets collected from GitHub, and experimental results show that our dual framework can improve the performance of CS and CG tasks over baselines.Comment: To appear at the 33rd Conference on Neural Information Processing Systems (NeurIPS) 201

A metamodel for the notation of graphical modeling languages

In order to define a graphical modeling language, it is,necessary to define the,graphical notation of the language in the process of metamodeling. So the defining of the notation has become one of the essential functions in metamodeling tools. This paper proposed the Notation Definition Metamodel (NDM) for metamodeling tools. NDM is used to define the graphical notation. It consists of three parts: basic figures and layouts, location relations and syntax bridges. NDM has been implemented in PKU MetaModel Tool (PkuMMT).. The paper made a case study to illustrate the feasibility of NDM. Besides, a comparison between PKU MMT and some metamodeling tools is presented to show the capability and advantages of NDM.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000249654000036&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Information SystemsComputer Science, Software EngineeringEngineering, Electrical & ElectronicCPCI-S(ISTP)

Sustainable cooling/lubrication induced thermo-mechanical effects on ultrasonic vibration helical milling of CFRP/Ti–6Al–4V stacks

Sustainable cooling/lubrication strategies including dry, minimum quantity lubrication (MQL), cryogenic (LN2) and hybrid (MQL and LN2) were used in ultrasonic vibration helical milling (UVHM) machining to improve the performance of hole-making for CFRP/Ti–6Al–4V stacks. The machining temperatures and forces were measured to characterize the thermo-mechanical effects on UVHM with different cooling/lubrication conditions. The machining temperatures at cryogenic conditions were −146 °C, −170 °C and −53 °C at CFRP layer, interface and Ti–6Al–4V layer, respectively. Axial and radial resultant forces at different conditions were highly related to the cutting temperature. Fiber removal mechanism at different conditions was analyzed according to the cutting temperatures, forces and the kinematic analysis in UVHM. Effects of sustainable cooling strategies and ultrasonic vibration on the hole surface texture of Ti–6Al–4V alloy were discussed. The amplitudes at different conditions varied approximately from 3.5 to 7 μm due to the variation of the forces. High precision of the exit geometry was achieved, as the height of hole exit burrs at Ti–6Al–4V layer were less than 40 μm except for the cryogenic condition. Diameters at the MQL and hybrid conditions were closer to the target diameter (ϕ10 mm), and the precision of the cylindricity of the machined holes of the stacks with the MQL and hybrid cooling conditions was higher than those at other conditions. Tool wear at different conditions were analyzed according to the SEM and EDS results. This work provided the fundamental understand of the hybrid process with sustainable cooling/lubrication strategy in UVHM machining. High quality of holes in CFRP/Ti–6Al–4V stacks were achieved by the hybrid processes