Resistance to carbonation of concrete after re-alkalization by absorption of sodium carbonate solution

The paper presents experimental research on the durability of a non-conventional technique for the repair of reinforced concrete damaged by carbonation-induced corrosion of steel reinforcement. The technique is called electrochemical re-alkalization and is often considered as an option for the repair of buildings, structures, and other artefacts made of reinforced concrete, for which conservation requirements are becoming increasingly important, in spite of their relatively young age. Absorption of a sodium carbonate solution is one of the processes that lead to concrete re-alkalization. The aim of the work is to investigate the contribution of this process to preventing future carbonation of re-alkalized concrete. Concrete specimens with six different compositions were initially carbonated, then re-alkalized through absorption of a sodium carbonate solution, and then exposed again to carbonation (re-carbonation). The results showed that the pH of concrete after re-carbonation was only slightly lower compared to that of re-alkalized concrete, highlighting a contribution of the treatment in preventing future pH reduction.     

Lexical Semantic Field as One of the Keys to Second Language Teaching

The article is devoted to the problem of the development of skills connected with the acquisition of foreign lexis (Lexis = all possible words or phrases in a language) on the basis of semantic fields (Semantic field = a lexical set of related items, e.g., colour, red, green, blue). This becomes possible due to grouping well-known and unknown to the students lexical units to systemized semantic groups—semantic fields. Semantic fields can be useful for the quantitative and qualitative enrichment of the vocabulary; they serve to choose a lexical unit correctly, to collocate lexical units according to existing norms, to use the lexis of various semantic fields in different contexts without mistakes, to guarantee conscious, automatic language skills of the students and to increase their active vocabulary.     

Planning and Doing in Professional Teaching Practice. A Study with Early Childhood Education Teachers Working with ICT (3–6 years)

Planning is one of the professional tasks teachers have to carry out before their direct action in the classrooms. This planning is closely interrelated to the way teachers teach. The question about how and why teachers reach their decisions in their pre-class planning is a classical one in the research into curricular design and development. The aim of this paper will therefore be to establish whether there is a relationship between curricular planning and curricular practices, studying how nine early childhood education teachers using an ICT resource plan their actions and execute them. For the research, we obtained video recordings of classroom practices and interviewed the teachers just before they went into class. By applying qualitative data analysis, we have been able to identify the elements taken into consideration when the teachers make decisions in lesson, their conceptions about ICT, and the types of activity that are held in all the classes. The results confirm the conclusions reached by previous studies on the relationships between planning and doing, in the sense that the activities, understood to be teaching strategies, are the ones that link the design of what is to be done and direct action. Likewise, the results ratify prior research on the role of materials and resources as aspects that teachers can rely on for support in the management and presentation of classroom tasks and content. The introduction of ICT does not modify the teachers’ curricular planning and development.     

Effects of an instructional gaming characteristic on learning effectiveness,efficiency, and engagement: using a storyline for teaching basic statistical skills

The study explored instructional benefits of a storyline gaming characteristic (GC) on learning effectiveness, efficiency, and engagement with the use of an online instructional simulation for graduate students in an introductory statistics course. A storyline is a game-design element that connects scenes with the educational content. In order to examine the interactions between the storyline GC and human performance, a storyline was embedded in a simulation. The goal of the simulation was to engage students in problem-solving and data analysis in the context of basic statistics by using real-world examples. The authors developed two different versions of the simulation: (1) Simulation+No GC, and (2) Simulation+Storyline GC. Both versions shared the same instructional content but differed in the presence or absence of a storyline GC. The results indicated that adding a storyline to a simulation did not result in significant improvements in learning effectiveness, efficiency, or engagement. However, both instructional methods (simulation and simulation with a storyline) showed significant learning gains from pre- to post-test. The findings of this study offer future directions for embedding a storyline GC into learning content.     

Which difficulties and resources do vocational teachers perceive? An exploratory study setting the stage for investigating teachers’ resilience in Switzerland

ABSTRACT

Based on an ecological view of teacher resilience, the paper investigates perceived difficulties and resources among vocational education and training (VET) teachers as a first step for investigating teachers’ resilience. Given the substantial shortage of theoretical and empirical studies on this population, more research on resilience among VET teachers is necessary and relevant. In this exploratory qualitative study, interviews with VET teachers in Switzerland (n = 37) sought to identify the specific challenges faced by teachers, the resources to be addressed. As well as confirming the different critical challenges and protective factors emerging from the literature review, the results identify difficulties and resources specific to VET teachers in Switzerland. In terms of critical challenges at a macro-contextual level, teachers’ low social recognition is emphasised. Moreover, exposure to curricular reforms generates stress and pressure related to the required standardisation of content and subject changes. At a micro-system level, we detected teachers’ frustration in relation to students’ low vocational motivation and maturity and specific emerging instructional challenges in vocational subject teaching. In terms of resources, teachers perceived the possibility of diversifying their professional role by alternating school and extracurricular activities as a supportive factor. The results provide a basis for more extensive quantitative study investigating relationship among adversities and resources and resilient strategies.     

Normalising: Children's activity to construct meanings for trend

This paper looks back over a number of exploratory studies which have researched young children's construction of meanings for graphs, produced from data entered in spreadsheets. In this paper we discuss children's use of normalising, an activity in which children correct data towards some perceived norm. Through normalising, children construct meanings for trend in data and in graphs. We discuss how particular aspects of the pedagogical setting including task design encourage the use of normalising.This revised version was published online in October 2005 with corrections to the Cover Date.     

Are secondary school graduates prepared for the studies of natural sciences? – evaluation and analysis of the result of scientific literacy levels achieved by secondary school graduates

ABSTRACT

Background: In Slovakia, no relevant information is available about the scientific literacy levels achieved by secondary school students.

Purpose: The objective of the research was to identify the levels of scientific literacy among students in the last year of grammar school and examine to what extent this determined the subject chosen for a school-leaving exam, which is related to a student’s personal preferences, as well as to the student’s profile and preparation for university education.

Sample: The research sample consisted of 221 students from 17 grammar schools located in various regions of Slovakia.

Design and methods: To identify the level of scientific literacy, we applied the Test of Scientific Literacy Skills.

Results: The students achieved the lowest success rate in the skill focused on the identification of the research design elements and its strengths and weaknesses. A comparably low success rate was also observed in the skill focused on the justification of the conclusions based on quantitative data. Other difficulties were identified in the field of understanding the basics of statistics, thus indicating an insufficient level of mathematical literacy of the students in the abovementioned field. By contrast, the highest success rate was achieved in the skill focused on the correct application of the scientific results for social purposes.

Conclusions: At the end of secondary school studies, the scientific literacy among Slovak students is at the average level. No differences were observed in terms of gender. In terms of the subjects chosen by the students for their school-leaving exams, we observed that those students who took a school-leaving exam in Biology or Chemistry achieved significantly better results in the test. By contrast, the students who reported on Geography and Civics as the subject of their school-leaving exam achieved significantly worse results in the test.     

Development of a spatially uniform low-temperature hydrogen combustor

Examples of the use of additive manufacturing and rapid prototyping in a range of applications are of great interest in order to emphasize their role in development and production technology. In this study, a catalytic low temperature burner for H₂ on a lab scale with an integrated flow distributor was designed, manufactured, and tested for functionality. Based on a theoretical approach, a flow distributor for the burner was designed and a prototype was built using fused deposition modeling (FDM). Based on test results, an optimized version of the burner was then designed and manufactured using selective laser melting (SLM). The functionality of the designed catalytic burner was proven. Several advantages were found in comparison to conventional non-catalytic burners. In particular, flameless uniform low temperature heat generation with temperatures of about 200 °C could be realized. This contribution highlights the potential of additive manufacturing in chemical engineering. Not only was the final product built using SLM, but also during the development process, FDM was used for rapid prototyping.     

The impact of stereoscopic imagery and motion on anatomical structure recognition and visual attention performance

Gross anatomy is located in a three‐dimensional space. Visualizing aspects of structures in gross anatomy education should aim to provide information that best resembles their original spatial proportions. Stereoscopic three‐dimensional imagery might offer possibilities to implement this aim, though some research has revealed potential impairments that may result from observing stereoscopic visualizations, such as discomfort. However, possible impairments of working memory such as decreased visual attention performance due to applying this technology in gross anatomy education have not yet been investigated. Similarly, in gross anatomy education the impact of stereoscopic imagery on learners’ recognition of anatomical‐spatial relationships and the impact of different presentation formats have only been investigated in a small number of studies. In this study, the performance of 171 teacher trainees working on the anatomy of hearing was examined, either with non‐stereoscopic or stereoscopic imagery. Static and dynamic picture presentations were applied. Overall, benefits for stereoscopic imagery on estimating anatomical‐spatial relations were found. The performance on a visual attention test indicates that the impact of stereoscopic visualizations on the human cognitive system varies more from person to person compared to non‐stereoscopic visualizations. In addition, combinations of temporarily moving pictures and stereoscopic imagery lead to decreased visual attention performance compared to combinations of moving pictures and non‐stereoscopic imagery. Anat Sci Educ 11: 15–24. © 2017 American Association of Anatomists.