Learning first principles theories under digital divide: Effects of virtual cooperative approach on the motivation of learning

Studies revealed that existing lockdowns due to COVID-19 across developing countries resulted in education access inequalities and challenges. Closure of schools and higher education institutions have forced educators to deliver courses and assessments distantly as an immediate countermeasure against threats on the academic progression of students. Specifically, students marginalized by digital divides were found to have less satisfaction in learning experiences under this emergency online learning method. For students with science and engineering background, it is a challenge to learn first principles theories in the online environment which could affect their learning motivation level. This paper presents the implementation of online cooperative learning in the course Material and Energy Balance which covered the fundamental principles of Chemical Engineering. The impact of virtual cooperative learning approach to reduce the loss of motivation due to digital divide was investigated. Firstly, it was found that most of the students, from different backgrounds of digital access, experienced a drop in motivation at the start of emergency online learning. Secondly, when virtual cooperative learning was implemented, an increase in students’ motivation at both sides of the digital divide was observed. The implications concerning provisions to design an all-inclusive online learning environment are also presented. We found that the incorporation of cooperative learning approach could contribute towards alleviating the drop in motivation, especially for the digitally disadvantaged students. We hope that the findings from this study could compel instructors or education practitioners to rethink and redesign the online teaching and learning activities to enable a more inclusive emergency online learning environment for digitally disadvantaged students.     

Present and future of wastewater reuse in Spain

This article contains an analysis of the current situation in Spain with respect to the reuse of treated effluent, outlining the different experiences obtained together with the future prospects. In matters concerning reuse, Spanish Law places particular emphasis on the planning of basic State regulations that are now being drawn up by the Ministry of Environment, as well as developing other supplementary tools for hazard control and the breakthroughs that are in the process of being made in the planning area. Finally, an account is given of a series of observations that the authors believe to be relevant with respect to achieving sustainable progress for reuse in Spain.     

采用color pilot软件处理数码照片评价牙齿的颜色变化

目的采用color pilot和Matlab软件处理数码照片及定点计算,评价数码照片是否能察觉牙齿颜色的变化。方法采用Vita比色板A2及C1作为试件,登士柏树脂附送的A2比色板作为参照,应用同一台数码照相机拍摄数码照片。根据光源、拍摄者、光圈、拍摄时间分组。将每张数码照片采用colorpilot软件处理,进行色彩矫正。结果经过计算机校正处理,同一试件的色差值基本上在1.5以下,有少数几项在1.5～3之间。其中,使用同一光圈的色差基本上都在1.5以下,不同的试验者,不同的时间,不同的照明环境对色差的影响并不明显。不同的光圈数值对色差的影响较大。不同的试件不论在何种条件下色差值均在3以上。结论经过色彩校正的数码照片可以察觉不同物体的颜色变化。     

A portfolio replacement for a traditional final exam in thermodynamics

As in many undergraduate chemical engineering courses, Bucknell University’s Chemical Engineering Thermodynamics course typically had a summative final exam that constituted a substantial portion of a student’s overall grade. In the spring 2020 semester, emergency remote instruction was instituted for the final six weeks of the semester, making a simultaneous timed exam a less attractive option for summative assessment. In place of the exam, students were asked to provide a portfolio of situations, calculations, and reflections documenting that they had achieved core learning outcomes. Assessment of these portfolios revealed comparable student performance on learning outcomes to those documented by exams in previous years. Students reported a generally favorable impression of the portfolio assignment, particularly given the novel remote-instruction circumstances. Portfolios took a similar amount of instructor time to grade using a rubric. This assignment is easily modifiable for use in other chemical engineering courses.     

R-curves determination of ordinary refractory ceramics assisted by digital image correlation method

As a figure-of-merit, the rising ratio of crack propagation resistance to fracture initiation resistance indicates a reduction of the brittleness and enhances the thermal shock resistance of ordinary refractory ceramics. The significant nonlinear fracture behaviour is related to the development of a fracture process zone (FPZ). The universal dimensionless load–displacement diagram method is applied as a promising graphical method for the determination of R-curves for magnesia refractories showing different brittleness. By applying digital image correlation (DIC) together with the graphical method, the problems arisen with accurate determination of the fracture initiation resistance and the crack length are overcome. Meanwhile, the R-curve is subdivided with respect to the fracture processes, viz the fracture initiation, the development of FPZ and the onset of traction free macro-crack. With the simultaneous crack lengths evaluated from DIC, the contribution of each fracture process to the crack propagation resistance at certain loading stage is quantitatively presented.     

从技术特性看卤化银照相和数码照相的前景(Ⅰ)

通过比较普通彩色胶卷与普通电子照相机 CCD及 CMOS的结构及其成像效率 ,分析了卤化银照相和数码照相的进展及其前景。预测彩色胶卷的成像效率有可能提高若干倍 ,它取决于入射光子的吸收效率以及吸收光子后转换成卤化银颗粒潜影中心的效率的提高；预测彩色胶卷在影像质量和成本方面相对于数码相机的优势将继续保持 ,因为 CCD的成像率由入射光子的吸收效率和光子被吸收后转换成光电子的效率决定 ,这两种效率都已经非常高 ,几乎没有改进的余地 ,而 CMOS则可以使数码照相机再上一个新台阶。     

Was den Digitalen Zwilling zum genialen Kompagnon macht

In international competition, the digital twin can be a decisive competitive advantage for German industry. This essay addresses characteristics of a digital twin from the user's point of view and is intended to help solution providers to give product development a customer-oriented direction. The different data models that play a role in the life cycles of chemical processes, plants and products are described. In particular for existing (brownfield) plants, essential aspects of the digital twin are formulated. Further characteristics and effects, e.g., on education and training, are derived from this.     

Plastic Extrusion Process Optimization by Digital Twins

Continuous plastics compounding processes are highly complex from a physicochemical point of view and correspondingly difficult to optimize. Model-based digital twins suitable for this purpose require complex simulation approaches, trained personnel and input variables that are difficult to determine. However, data-based digital twins, which are in principle suitable for this purpose, often fail because of the enormous trial effort which is required to generate a sufficiently large database. To overcome this problem this paper describes a hybrid approach for generating the necessary database for a data-based digital twin. By intelligent combination of real experiments, adaptation of the physical-chemical process model to these few experimental data and subsequent data cloud generation with the adapted process model results in a sufficient data base for the digital twin.     

《无机材料合成》课程的教学探讨

无机材料合成是材料科学的专业基础课。文章结合笔者实际教学过程的经验和对该课程的教学方面的思考,从教学内容、教学目的、教学方式、教学效果等几个方面对《无机材料合成》课程教学进行初步探讨。在课程教学过程中实现内容上经典与新颖性相结合,教学方式上传授与启发相结合、传统工具和现代化多媒体工具相结合,教学思想上精确系统性与人文渗透相结合,目的是使学生系统地了解课程涉及的知识,同时提高专业素质、科学修养以及科研兴趣。     

Accurate size measurement of needle-shaped particles using digital holography

In this paper, a digital holography based method is proposed to accurately measure the length and orientation of the needle-shaped particles in solution. The method involves recording of the hologram and numerical reconstructions (focusing) of the hologram at several depths. An image analysis routine is then used to determine the length, location and orientation of the particles from the reconstructed images without any a priori information about the orientation of particles. The performance of the method is verified using a single fiber with known size and orientation. Subsequently, the proposed method is applied to a suspension of fibers, where the length measurements are found to be in good agreement with the true values. This proposed technique can overcome the shortcoming of existing 2D imaging tools, which can provide only the projected lengths of randomly oriented particles.     

《普通化学》精品课程建设的实践与思考

从四个方面阐述了我们《普通化学》课程建设的工作思路和取得的成果,加强师资队伍的建设从三个方面做起,课程体系和内容的改革重点是抓好教学内容及课程体系优化与整合,教学方法及实验教学的改革是课程建设的重要环节。希望我们在《普通化学》课程建设和教学改革中的一些实践和体会能给大家一点借鉴和参考。     

Courses Based on iGEM/BIOMOD Competitions Are the Ideal Format for Research-Based Learning of Xenobiology

Synthetic biology and especially xenobiology, as emerging new fields of science, have reached an intellectual and experimental maturity that makes them suitable for integration into the university curricula of chemical and biological disciplines. Novel scientific fields that include laboratory work are perfect playgrounds for developing highly motivating research-based teaching modules. We believe that research-based learning enriched by digital tools is the best approach for teaching new emerging essentials of academic education. This is especially true when the scientific field as such is still not canonized with text books and best-practice examples. Our experience shows that iGEM/BIOMOD competitions represent an excellent basis for designing research-based courses in xenobiology. Therefore, we present a report on “iGEM–Synthetic Biology” offered at the Technische Universität Berlin as an example.     

A quantitative study on the surface crack pattern of concrete with high content of steel fiber

The mechanical properties and digital image analysis of slurry-infiltrated fiber reinforced concrete (SIFCON) were investigated experimentally. Fractal dimension is used as a parameter to characterize the crack pattern on the surface of SIFCON. It is found that there exists fractal phenomenon for different fiber contents of SIFCON, fractal dimension can be a parameter to characterize crack pattern on the surface of SIFCON quantitatively, and there exists a good correlation between mechanical properties and fractal dimension.     

陶瓷洁具数字化设计和制造技术的研究

介绍了卫生陶瓷洁具设计技术的现状、数字化设计和制造技术的研究成果。数字化设计和制造技术是将陶瓷工艺、工业产品设计、GAD／GAM、数控加工、流体仿真、计算机软件和数据库技术结合在一起的、具有高度技术集成和智能数字化的先进技术，造型设计参数化、结构设计参数化、快速制模和数字化测试技术是其主要组成部分。利用该技术开发的新产品品质、排污功能优良，极具环保性能、造型价值和文化价值，能降低开发成本。     

Digitising Teaching and Learning – Additional Perspectives for Chemistry Education

Chemistry requires and combines both observable and mental representations. Still we know that learners often struggle in combining these perspectives successfully, especially when experimental observations contradict the model‐based explanations, e. g. in interpreting the chemical equilibrium as dynamic processes while observing a static system without any visible changes. Digital media offer potentials that might not have been accessible to this degree until now. However, we do not know enough with regard to the degree and effects these media tools have in supporting learning processes but perhaps also in hindering them. This article presents four approaches on how to potentially make use of digital media in learning processes based on theoretical considerations and empirical investigations. The projects will explore applications of media as visualization, learning and investigation tools in chemistry education, embracing techniques from virtual realities to eye‐tracking.     

炼厂催化装置主风机电机启动方式仿真研究

某企业电网改造过程中,催化装置备用风机由4 MW增容为10 MW,采用理论计算分析大电机启动方式时,面临未知参数过多、计算复杂的问题。应用数字仿真技术,建立企业电网模型,对催化备机不同的启动方式进行了仿真、分析和评价。分析结果表明,某企业增容后的催化备机不允许直接启动,可以选择软启动,宜使用变压器启动。实践表明,数字仿真技术为企业高压大电机启动方式的选择和设计提供了一种简单、可靠的技术。     

档案袋评价在无机化学教学中的应用

档案袋评价是一种从实践中涌现出的评价方法,它弥补了标准化考试的弊端。本文分析了传统评价方法的局限和不足,提出了档案袋评价应用于无机化学教学的策略,并结合一个学期的无机化学教学实践对档案袋评价方法进行了研究。探索档案袋评价应用于高校教学的可行性。     

ACHEMA 2022 – Digital Twins

Process development and quality assurance through interconnected structures between the digital and real worlds are often reflected in digital twins. This article summarizes current trends and developments, their special features, but also the challenges of digital twins. The report includes a selection of different new and further developments, possible applications and research projects that were exhibited at ACHEMA 2022.     

复合材料数字化技术的研究进展与应用

综述了国内外复合材料数字化技术的研究进展,指出了国内数字化技术与国外发达国家存在的差距.从复合材料工装数字化设计、预浸料自动下料、激光铺层定位、纤维自动铺放和自动化无损检测等方面介绍了复合材料数字化技术的应用.     

On the calibration of cohesive parameters for refractories from notch opening displacements in wedge splitting tests

Cohesive elements are commonly used to describe crack propagation in heterogeneous materials with toughening mechanisms. This work aims to provide a guideline on how these fracture parameters can be calibrated using notch opening displacements (NODs) measured via digital image correlation and force data from wedge splitting tests (WSTs). Weighted finite element model updating was applied to calibrate material and boundary condition parameters in the same framework. The influence of each parameter on force and NOD data are given together with uncertainties for the calibrated parameters. Numerical results were in very good agreement in terms of splitting force, NOD, displacement and gray level residual fields. It is shown that images obtained during WSTs focusing on the crack path (i.e., hiding the loading region) can be used to drive numerical simulations and obtain cohesive parameters.