THE EXPERIMENT AND ANALYSIS OF ACTIVE MECHANISMS FOR ENHANCING HEAT AND MASS TRANSFER IN SORPTION FLUIDS

This project was funded by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE RP-1462). It is a three years’ research, including the literature review, labs construction, experiments and data analysis. In this thesis, first of all, we conducted literature review of mechanism motion influence on heat and mass transfer and additive effect in absorption chiller. This part helps us understand the basic idea of how mechanism motion affects the heat and mass transfer of sorption fluids and gives us reference on how to select the experiment instrument and the experiment operation range. In the second part, the instrument selection and lab construction are introduced. A commercial absorption chiller, a vertical vibration table and a statistic water loop system are used in our lab. This test facility has the capability of realizing mechanism motion in real systems with adjustable wide range vibration and long term stabilized auxiliary water supply. A commercial absorption chiller with a capacity of 10kW is utilized in this project. A water loop system was constructed to maintain a repetitive experimental condition when the outdoor conditions change. We also installed a data acquisition system for in-line measurement of the solution concentration and temperature and flow rate of the solution and water loops. We can use these measurements to calculate the heat and mass transfer capacity in the absorber in steady-state. The enhancement is obtained by comparing the temperature differences, before a vibration and during a vibration. In the third section, we illustrate the methodology of how to analyze the heat and mass transfer in the absorber and the data under different conditions. We separate the experiment into three big groups, including the conditions without additive, with n-octanol additive and with 2-ethylhexanol(2EH) additive. Different film thickness (spray amount), vibration frequency, and vibration amplitude comparisons were considered under each condition. And we also cross-compared all these three groups. The results of this project revealed the optimal frequency and amplitude combinations (at 25 Hz & 0.2mm) for the absorption chiller tested in this study. The results of this project provided information filling the knowledge gap about the influence of mechanical motion in absorption chiller technology. Advisor: Yuebin Y

THE EXPERIMENT AND ANALYSIS OF ACTIVE MECHANISMS FOR ENHANCING HEAT AND MASS TRANSFER IN SORPTION FLUIDS

This project was funded by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE RP-1462). It is a three years’ research, including the literature review, labs construction, experiments and data analysis. In this thesis, first of all, we conducted literature review of mechanism motion influence on heat and mass transfer and additive effect in absorption chiller. This part helps us understand the basic idea of how mechanism motion affects the heat and mass transfer of sorption fluids and gives us reference on how to select the experiment instrument and the experiment operation range. In the second part, the instrument selection and lab construction are introduced. A commercial absorption chiller, a vertical vibration table and a statistic water loop system are used in our lab. This test facility has the capability of realizing mechanism motion in real systems with adjustable wide range vibration and long term stabilized auxiliary water supply. A commercial absorption chiller with a capacity of 10kW is utilized in this project. A water loop system was constructed to maintain a repetitive experimental condition when the outdoor conditions change. We also installed a data acquisition system for in-line measurement of the solution concentration and temperature and flow rate of the solution and water loops. We can use these measurements to calculate the heat and mass transfer capacity in the absorber in steady-state. The enhancement is obtained by comparing the temperature differences, before a vibration and during a vibration. In the third section, we illustrate the methodology of how to analyze the heat and mass transfer in the absorber and the data under different conditions. We separate the experiment into three big groups, including the conditions without additive, with n-octanol additive and with 2-ethylhexanol(2EH) additive. Different film thickness (spray amount), vibration frequency, and vibration amplitude comparisons were considered under each condition. And we also cross-compared all these three groups. The results of this project revealed the optimal frequency and amplitude combinations (at 25 Hz & 0.2mm) for the absorption chiller tested in this study. The results of this project provided information filling the knowledge gap about the influence of mechanical motion in absorption chiller technology. Advisor: Yuebin Y

An Evaluation Study on the Level of China's Low-Carbon Manufacturing Based on Factor Analysis

AbstractBased on the absorption of some relevant research results, this paper establishes an evaluation model of the level of China's low-carbon manufacturing and uses the factor analysis method for empirical research. Then it analyses the exist problems of China's low-carbon manufacturing and puts forward some relevant countermeasures and suggestions

DeepE: a deep neural network for knowledge graph embedding

Recently, neural network based methods have shown their power in learning more expressive features on the task of knowledge graph embedding (KGE). However, the performance of deep methods often falls behind the shallow ones on simple graphs. One possible reason is that deep models are difficult to train, while shallow models might suffice for accurately representing the structure of the simple KGs. In this paper, we propose a neural network based model, named DeepE, to address the problem, which stacks multiple building blocks to predict the tail entity based on the head entity and the relation. Each building block is an addition of a linear and a non-linear function. The stacked building blocks are equivalent to a group of learning functions with different non-linear depth. Hence, DeepE allows deep functions to learn deep features, and shallow functions to learn shallow features. Through extensive experiments, we find DeepE outperforms other state-of-the-art baseline methods. A major advantage of DeepE is the robustness. DeepE achieves a Mean Rank (MR) score that is 6%, 30%, 65% lower than the best baseline methods on FB15k-237, WN18RR and YAGO3-10. Our design makes it possible to train much deeper networks on KGE, e.g. 40 layers on FB15k-237, and without scarifying precision on simple relations.Comment: 10 pages, 5 figures, 7 table

Design and performance testing of a monolithic nickel-based SiC catalyst for steam methane reforming

Hydrogen is a highly promoted carbon-free energy carrier that has drawn significant attention recently due to its potential to decarbonise energy sector. More than three-quarters of hydrogen is currently produced via steam methane reforming (SMR), and nickel-based catalysts are used in most applications. Structured catalysts have been reported to be able to further improve catalyst performance as they can optimise heat and mass transfer, as well as prevent coke formation with its structural and textural proprieties. Silicon carbide (SiC) has excellent hardness, thermal conductivity, and chemical inertness, therefore is a promising material to develop structured nickel-based monolithic SiC catalysts for SMR. In this work, a structured monolithic catalyst support has been formed by a modified freeze-gelation method, initially starting from SiC powder, and nickel has been distributed to form a monolithic nickel-based catalyst by wet impregnation. The results showed that the catalysts can achieve thermodynamic equilibrium at 600 °C with a gas hourly space velocity (GHSV) of 10,000 h−1, while reaching a high methane conversion of 86% at 800 °C and GHSV value of 20,000 h−1 during the performance tests using low feeding concentration and low pressure. This is the first time SiC catalytic materials have had their performance demonstrated for SMR under realistic operating conditions

Research on comment target extracting in Chinese online shopping platform

Purpose - This paper aims to extract the comment targets in Chinese online shopping platform. Design/methodology/approach - The authors first collect the comment texts, word segmentation, part-of-speech (POS) tagging and extracted feature words twice. Then they cluster the evaluation sentence and find the association rules between the evaluation words and the evaluation object. At the same time, they establish the association rule table. Finally, the authors can mine the evaluation object of comment sentence according to the evaluation word and the association rule table. At last, they obtain comment data from Taobao and demonstrate that the method proposed in this paper is effective by experiment. Findings - The extracting comment target method the authors proposed in this paper is effective. Research limitations/implications - First, the study object of extracting implicit features is review clauses, and not considering the context information, which may affect the accuracy of the feature excavation to a certain degree. Second, when extracting feature words, the low-frequency feature words are not considered, but some low-frequency feature words also contain effective information. Practical implications - Because of the mass online reviews data, reading every comment one by one is impossible. Therefore, it is important that research on handling product comments and present useful or interest comments for clients. Originality/value - The extracting comment target method the authors proposed in this paper is effective

The gut microbiome: A line of defense against tuberculosis development

The tuberculosis (TB) burden remains a significant global public health concern, especially in less developed countries. While pulmonary tuberculosis (PTB) is the most common form of the disease, extrapulmonary tuberculosis, particularly intestinal TB (ITB), which is mostly secondary to PTB, is also a significant issue. With the development of sequencing technologies, recent studies have investigated the potential role of the gut microbiome in TB development. In this review, we summarized studies investigating the gut microbiome in both PTB and ITB patients (secondary to PTB) compared with healthy controls. Both PTB and ITB patients show reduced gut microbiome diversity characterized by reduced Firmicutes and elevated opportunistic pathogens colonization; Bacteroides and Prevotella were reported with opposite alteration in PTB and ITB patients. The alteration reported in TB patients may lead to a disequilibrium in metabolites such as short-chain fatty acid (SCFA) production, which may recast the lung microbiome and immunity via the “gut-lung axis”. These findings may also shed light on the colonization of Mycobacterium tuberculosis in the gastrointestinal tract and the development of ITB in PTB patients. The findings highlight the crucial role of the gut microbiome in TB, particularly in ITB development, and suggest that probiotics and postbiotics might be useful supplements in shaping a balanced gut microbiome during TB treatment

Ni-based bimetallic catalysts for hydrogen production via (sorption-enhanced) steam methane reforming

The catalytic performance of a monometallic Ni/Al2O3 and three bimetallic catalysts (Ni3M1/Al2O3, with M = Cu, Fe, and Ge) for the (sorption-enhanced) steam methane reforming reaction was evaluated. Ni3Cu1/Al2O3 was found to be the optimal catalyst in terms of methane conversion, hydrogen yield, and purity. Ge also has a promoting effect on the monometallic Ni catalyst, whereas the addition of Fe negatively influenced its performance. Physico-chemical characterization of the materials indicated the formation of alloys upon activation of the materials with hydrogen. The addition of Cu increased the surface area and metal dispersion, and improved the overall morphology of the catalyst. The experimental observations were also supported by a numerical study combining Density Functional Theory-based calculations and Microkinetic modelling of the SMR process. Ni3Cu1 and Ni3Ge1 were calculated to have a similar level of catalytic activity as Ni, whereas Ni3Fe1 was unsuitable for the reaction. The SMR reaction was further improved by adding calcium oxide as the CO2 sorbent, which increased methane conversion, CO selectivity, hydrogen yield, and hydrogen purity. The highest methane conversion of 97 % was achieved by Ni/Al2O3 and Ni3Cu1/Al2O3 at 700 °C