A detailed anatomy of students’ perception of engagement and their learning a threshold concept in core chemical engineering

An attempt has been made to reveal a detailed anatomy of students’ self-perceived engagement with material in a lecture and their learning of a key course threshold concept. A cohort of 80 students in a third year chemical engineering (64% response rate) course voluntarily recorded their engagement using a Likert-type scale at intervals of 5 min in a (nominally 50 min) lecture, together with written comments. Marks were awarded for a substantial, follow-up summative assignment to test their understanding of the threshold concept. It was found students were highly unaligned in their level of engagement with the lecture. A key reason was that individuals’ engagement varied highly significantly during the lecture. Six engagement styles were identified. Some 33% exhibited Type 1 (engage strongly at the start and slowly disengage) and 23% exhibited Type 2 (remain at a more or less fixed engagement). Significantly, there was no correlation between students’ engagement scores and marks awarded; in particular there was no correlation with specific lecture intervals in which material was identified as most important. Further, there was no correlation between the number of written comments made by an individual and their marks. It is concluded that student self-perceived engagement is not a good predictor of learning as assessed by marks awarded on a summative assignment. It is not known whether student engagement is predicated on particular lecture material and type of lecturer, or other contributing factors. The experimental design could be readily widely applied.     

HAZOP分析方法在化工原理实验教学中的应用

化工原理实验是促进学生理解化工单元操作、培养学生工程实践能力的一门重要课程,而化工安全是其中必不可少的教学内容。为适应新工科教学改革的需要,文章提出将HAZOP分析方法引入化工原理实验教学中,介绍了针对化工原理实验装置进行HAZOP分析的方法和流程,并以“圆形直管中气体对流传热系数的测定”实验项目为例,介绍了其应用过程。实践表明,HAZOP安全分析方法用于化工原理实验教学能够巩固和加深学生对理论知识的理解,培养学生的创新意识和安全意识,提高学生分析和解决复杂工程问题的能力。     

Introducing students to research codes: A short course on solving partial differential equations in Python

Recent releases of open-source research codes and solvers for numerically solving partial differential equations in Python present a great opportunity for educators to integrate these codes into the classroom in a variety of ways. The ease with which a problem can be implemented and solved using these codes reduce the barrier to entry for users. We demonstrate how one of these codes, FiPy, can be introduced to students through a short course using progression as the guiding philosophy. Four exercises of increasing complexity were developed. Basic concepts from more advanced numerical methods courses are also introduced at appropriate points. To further engage students, we demonstrate how an open research problem can be readily implemented and also incorporate the use of ParaView to post-process their results. Student engagement and learning outcomes were evaluated through a pre and post-course survey and a focus group discussion. Students broadly found the course to be engaging and useful with the ability to easily visualise the solution to PDEs being greatly valued. Due to the introductory nature of the course, due care in terms of set-up and the design of learning activities during the course is essential. This course, if integrated with appropriate level of support, can encourage students to use the provided codes and improve their understanding of concepts used in numerical analysis and PDEs.     

Three classic ultrafiltration problems solved with the Exponential Integral

Three problems from ultrafiltration process design and analysis, typically solved using numerical methods, are solved analytically with the aid of the Exponential Integral special function. The lesson for the chemical engineering student is to always consider the possibility that analytical solutions involving special functions might exist for problems previously thought to be solvable with numerical methods only. When encountering new integrals, even ones that seem intractable, students should consider the use of a symbolic integrator to check if an easily implementable analytical solution exists, even one based on unfamiliar functions.     

化工原理实验教学的探索

化工原理实验是化学工程及化工类相近专业的一门重要基础课程。它是培养学生工程观点、实践能力和创新能力的一个重要环节。为加强学生对该课程的理解以及提高学生独立操作实验的能力,文章结合作者多年的教学实践,从实验教学的方法和实验的考核这两方面,就如何提高化工原理实验教学的质量进行了积极地探索与实践。     

食品工艺学综合设计试验的探索与实践

《食品工艺学实验》是食品科学与工程专业重要的实践课程,文章研究的内容是让学生选择试验内容、设计试验方案、评价试验结果,教师全程指导与跟踪,这种教学方法充分提高了学生的学习兴趣,培养了学生的思考能力,3年的教学结果表明这种教学方法是有成效的。     

化工原理实验教学探索

化工原理实验是化工专业的学生的一个重要的实践性教学环节。为提高学生的学习积极性,提高实验教学质量,文章探索了教学内容、教学方法、教学过程以及考核方式的改革,通过实践,并取得了较好的效果。     

SOPDT模型不确定性界及其在内模控制器设计中的应用

引　言内模控制 (ＩＭＣ)是一种在化工过程中有广泛应用前景的鲁棒控制 ,由于这一先进控制能保证系统的鲁棒稳定性和鲁棒性能 ,从而在过程控制界引起了极大的兴趣[1～ 8] .鲁棒控制器设计的必要条件之一 ,是首先要有实际过程的不确定信息 ,即模型 (或过程 )的不确定性界[7] .对于在过程控制中经常采用的一阶加纯滞后过程 (ＦＯＰＤＴ) ,其模型不确定性界的计算方法已有报道[5～ 7,9] .然而 ,过程控制中常常会遇到二阶加纯滞后过程 (ＳＯＰＤＴ) ,有时更高阶的过程采用ＦＯＰＤＴ模型来近似往往不能保证闭环系统的性能 ,需要采用ＳＯＰＤＴ模…     

Ausbreitung explosibler Gaswolken in der Nähe von Anlagen der Chemischen Industrie

Propagation of explosive gas clouds in the vicinity of chemical plant . The propagation of large amounts of gases in the vicinity of industrial plant can lead to safety risks and must therefore be estimable in their effect. Methods of both theoretical and experimental simulation are available. Among the computational models, the conventional propagation models used in meteorology are suitable for free propagation. In cases of propagation close to buildings, the relatively straightforwardly applied binomial model is a better choice. Owing to the occurrence of turbulence, the calculations should be supported by wind tunnel studies. An unfavourable system leading to accumulation of large amounts of gas is seen to be a U-shaped arrangement of buildings with incident flow on the convex side.     

Propagation of detonation waves in gas suspensions in channels with a backward-facing step

Propagation of heterogeneous detonation in a mixture of oxygen and fine aluminum particles in a plane channel with a backward-facing step is studied numerically. The plane detonation regime is taken as the initial flow in the narrow part of the channel. Possible scenarios of evolution of this flow after its passage to the expanded part of the channel are analyzed. The effect of the particle size and channel geometry on detonation propagation/failure is found. Cellular detonation is formed in the wide part of the channel, with a subsequent change in the cell size in the course of establishment of a steady propagation regime. The cell size in steady regimes is invariant with respect to the flow formation process.     

Exit of a heterogeneous detonation wave into a channel with linear expansion. I. Propagation regimes

Propagation of a plane detonation wave in a stoichiometric mixture of a gas and aluminum particles in a plane channel with a linear expansion section is studied by methods of numerical simulation. The slope of the wall is varied from 15 to 60°. The basic regimes of detonation propagation are analyzed: supercritical (without detonation failure), critical (with partial failure and re-initiation), and subcritical (with complete separation of the shock front and combustion front and with detonation failure). The detonation configuration formed in the expanding section can be a cellular structure with large differences in cell sizes at large angles of expansion or a close-to-uniform structure at the wall angle of 15°.     

The impact of focused degree projects in chemical engineering education on students’ research performance,retention, and efficacy

Recent reforms in engineering education have emerged to meet the changing needs of engineers, however sparse research exists that comprehensively assesses the outcomes associated with such engineering education efforts. Accordingly, there is an urgent need for educational approaches tied to assessing engineering students’ performance, retention, and impact.This study's purpose is to explore the relationship between sequential chemical engineering degree projects and students’ performance, engineering efficacy, multidisciplinarity, and retention. The projects for this education for chemical engineers research are thematically focused laboratory experiments embedded in a four-year chemical engineering program. Each project component is connected to the next, is increasingly complex as courses advanced, and is aligned with essential course content. This connectivity enables students to participate in logically sequenced experiments that culminate in well-developed senior laboratory projects. This study's educational impact was determined via comparison between seniors’ and freshmen’ performance, efficacy and retention.Results of this research indicate that the use of degree projects in chemical engineering education is impactful, resulting in students’ increased understanding of experimentation and course content; meaningful, resulting in statistically significant increased student chemical engineering efficacy; and engaging, resulting in students’ satisfaction with program impact, engagement with peers during experimentation, and dramatically increased student retention.     

《聚合物研究方法》教学改革的探索

《聚合物研究方法》是高分子材料与工程专业学生的一门十分重要的必修课。文章以培养学生的工程能力,专业实验能力和创新能力,提高专业教学质量为目的,针对聚合物研究方法课程教学过程中存在的问题,在教学内容、方法、手段、实践上进行了一些改革探索。文章认为聚合物研究方法的教学改革应从更新教学内容,采用多元化、现代化的教学手段,加强实验教学环节,改革考核方法入手,达到改善学生的专业知识结构,培养学生理论联系实际,将知识转化为能力的目的。     

ANALYSIS OF RANDOM AND SYSTEMATIC ERROR EFFECTS ON UNCERTAINTY PROPAGATION IN PROCESS DESIGN AND SIMULATION USING DISTRIBUTION TAIL CHARACTERIZATION

An exponential and heavy tail analysis method is presented to study the effect of systematic and random errors present in thermodynamic data on chemical process design and simulation. The true distribution tail characteristics (important for high levels of quality assurance) can be far from the estimates obtained with typical Gaussian distribution analysis. Pareto (heavy) or exponential distributions may represent the tail behavior better under many circumstances. Heavy tails diminish at an algebraic rate rather than at an exponential rate. Different error types such as random and systematic error can potentially cause different effects in the behavior of probability distributions, particularly in the tails. In this work, we use the tail behavior of cumulative frequency distributions produced from uncertainty analyses to characterize the error propagation in process design and simulation. The diminishing rate of the tail of a given distribution can be related to the error types involved in the process and also can be used to determine which error exhibits stochastic dominance. Case studies of process performance evaluations for liquid-liquid extraction operations are presented to illustrate the approach. It is observed that random and systematic errors (coupled with typical nonlinear chemical engineering models) can cause the tails of the uncertainty probability distributions to be exponential.     

Teaching water desalination through active learning

Active learning refers to the direct involvement of students in the learning process rather than being passive receptors of materials. This paper evaluates the implementation of active learning in teaching seawater desalination as an elective course in chemical engineering curriculum. Desalination is a multi-disciplinary engineering science that encompasses elements of water chemistry, material science, transport phenomena, thermodynamics, engineering design, and corrosion. Water desalination is an important course in most chemical and mechanical engineering curricula, where the design and analysis of different water desalination processes are addressed. The current teaching method, however, relies heavily on classical lecture-presentation of the course materials, without any direct involvement of the students. A simple approach that utilizes Excel and Ez-Solve in designing and analyzing desalination processes has been developed. Active learning is the central part of this course development, where students are heavily involved in class activities and can directly assess the effect of input variables on the design parameters, allowing them to carry out “What If” or parameter sensitivity analysis.     

ANALYSIS OF RANDOM AND SYSTEMATIC ERROR EFFECTS ON UNCERTAINTY PROPAGATION IN PROCESS DESIGN AND SIMULATION USING DISTRIBUTION TAIL CHARACTERIZATION

An exponential and heavy tail analysis method is presented to study the effect of systematic and random errors present in thermodynamic data on chemical process design and simulation. The true distribution tail characteristics (important for high levels of quality assurance) can be far from the estimates obtained with typical Gaussian distribution analysis. Pareto (heavy) or exponential distributions may represent the tail behavior better under many circumstances. Heavy tails diminish at an algebraic rate rather than at an exponential rate. Different error types such as random and systematic error can potentially cause different effects in the behavior of probability distributions, particularly in the tails. In this work, we use the tail behavior of cumulative frequency distributions produced from uncertainty analyses to characterize the error propagation in process design and simulation. The diminishing rate of the tail of a given distribution can be related to the error types involved in the process and also can be used to determine which error exhibits stochastic dominance. Case studies of process performance evaluations for liquid-liquid extraction operations are presented to illustrate the approach. It is observed that random and systematic errors (coupled with typical nonlinear chemical engineering models) can cause the tails of the uncertainty probability distributions to be exponential.     

Analytical and Numerical Calculation of the Energy Release Rate for the Microbond-Test

The energy release rate for interface crack propagation for the Microbond-Test specimen is calculated by using several stress analysis methods. For the corresponding finite element calculation an axisymmetrical model (elliptical droplet) and linear elastic material properties are used. The analytical approximations use several stress analysis methods to obtain the energy release rate.

The resulting energy release rate curves suggest that the debonding process can be described at least partially as a stable crack propagation along the interface. Some experiments confirm this prediction. The matrix droplet contribution to the energy release rate can be considerable. Because of the very complex stress fields in the droplet a simple analytical approximation cannot be given. The qualitative dependences on the material properties and on the geometry can be explained from the presented analysis. The remaining correction factor can be obtained from a numerical calculation.     

无机及分析化学实验教学内容改革的探索

化学实验是化学课程教学的重要内容之一。根据我校食品科学与工程专业教学大纲的要求,进行了无机化学实验和分析化学实验课程整合。通过合理安排实验内容,能够激发学生的学习兴趣,有效提高实验教学效果和学生的实验操作技能。     

化工原理课程的教学研究与实践

化工原理是化工类及相近专业的技术基础课和主干课,是承前启后、由理及工的桥梁,又是各种专业课的基础,属于工程技术科学的范畴,重点向学生介绍化工单元操作的基本原理,典型设备的构造及工艺尺寸的计算或选型,授课中紧紧抓住动量传递、热量传递、质量传递这条主线,理解掌握物料衡算,能量衡算,平衡关系,传递速率及经济核算这五大关系,强...     

化学反应过程与设备教学改革与实践

化学反应过程与设备是化工类学生的专业基础课,对培养学生的化学反应工程基础、提高工程分析能力具有重大作用。文章针对化工职业技术学院的办学特点,阐述了化学反应过程与设备在教学过程中在教学内容、教学方法及实践教学过程中的改革,以提高学习效率和学生的就业能力。