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"Clips"
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Performance of Biodegradable Biochar-Added and Bio-Based Plastic Clips for Growing Tomatoes
Increasing quantities of waste from using conventional plastic in agriculture and horticulture is one of the most pressing issues nowadays. Conventional plastic accessories (e.g., mulching films, clips, pots, strings, etc.) are typically fossil-derived, non-biodegradable and difficult to recycle after their use. Therefore, there is a need for biodegradable and bio-based alternatives with similar properties to conventional plastics, which can be disposed of through degradation in water, soil or compost under specific conditions. This work investigated the properties and the performance of biodegradable biochar-added and bio-based stem and arch support clips. In addition, the investigated clips were composted with tomato residues during 16 week laboratory composting. The scope of this work included: (1) the production of stem and arch support clips in a pilot installation using injection molding technology, (2) an analysis of their chemical composition, biodegradability, disintegration and phytotoxicity, (3) an evaluation of their performance in the greenhouse cultivation of tomatoes and (4) an evaluation of the composting of the clips with on-farm organic waste as an end-of-waste management method. The stem support clips during industrial composting (58 °C) degraded at 100% after 20 weeks, whereas during home composting (30 °C) the degradation was slow, and after 48 weeks the maximum weight loss was 5.43%. Disintegration during industrial composting resulted in 100% fragmentation into particles with sizes less than 2 mm. Phytotoxicity tests demonstrated that the substrates after industrial and home composting did not have a negative effect on the growth of the test plants (i.e., mustard, wheat, cuckooflower). The biochar-added stem support clips proved to be satisfactory alternatives to conventional non-biodegradable, fossil-derived clips and can be disposed of through composting. However, more work is needed to determine the optimal conditions for composting to ensure rapid degradation of the clips in relevant environments.
Journal Article
Measuring Usable Knowledge: Teachers' Analyses of Mathematics Classroom Videos Predict Teaching Quality and Student Learning
This study explores the relationships between teacher knowledge, teaching practice, and student learning in mathematics. It extends previous work that developed and evaluated an innovative approach to assessing teacher knowledge based on teachers' analyses of classroom video clips. Teachers watched and commented on 13 fraction clips. These written analyses were coded using objective rubrics to yield a reliable and valid indicator of their usable teaching knowledge. Previous work showed this measure to correlate with another measure of teacher knowledge and to predict students' learning from the teachers' fraction instruction. In this study, the authors replicated those findings and further showed that the effect of teacher knowledge on student learning was mediated by instructional quality, measured using video observations of teachers' lessons.
Journal Article
Natural vibration of pipes conveying high-velocity fluids with multiple distributed retaining clips
Pipes are usually constrained by multiple distributed retaining clips (MRCs). In addition, piping fluids are always required for higher velocities. In this paper, the effect of MRCs distribution on the natural vibration of pipes conveying high-velocity fluids are investigated. The nonlinear dynamical model of multi-span pipes conveying fluids is established by the generalized Hamiltonian principle. The critical velocity of fluid-conveying pipes is obtained. Then, the supercritical static equilibrium bifurcation appears in the pipe conveying high-velocity fluids. Subsequently, the non-trivial static equilibrium configuration is solved by developing the iterative scheme. By coordinate transformation, the governing equation of the pipe constrained by MRCs is established in the supercritical regime. Some meaningful and interesting results are obtained. Results show that the critical velocity of a multi-span (more than two-span) pipe is not monotonous with the change of the clip location. For pipes with single clip and two or more clips, the critical velocity varies significantly with the trend of clip stiffness. With the increase of flow velocity, the modes of multi-span pipes change significantly. Moreover, the first-order natural frequency of the three-span pipe is not monotonous with the change of clip stiffness, number, and location in the supercritical regime. Therefore, as a common and important pipe form in engineering, more attention should be paid to pipes with multiple distributed retaining clips.
Journal Article
Novel biodegradable magnesium alloy clips compared with titanium clips for hepatectomy in a rat model
Background
The use of surgical metal clips is crucial for ligating vessels in various operations. The currently available metal clips have several drawbacks; they are permanent and interfere with imaging techniques such as computed tomography (CT) or magnetic resonance (MR) imaging and carry the potential risk of endo-clip migration. We recently developed a novel magnesium (Mg) alloy for biodegradable clips that reduces artifacts on CT imaging. This study aimed to examine the tolerance, biodegradability, and biocompatibility of the Mg alloy clips compared with those of standard titanium (Ti) clips in hepatectomy.
Methods
Thirty Wistar rats were divided into two groups based on the clip used (groups A and B). The vascular pedicle, including hepatic artery, portal vein, bile duct, and hepatic vein of the left lateral lobe, was ligated with the Ti clip in group A or the Mg alloy clip in group B, and then the left lateral lobe was removed. The rats were sacrificed at 1, 4, 12, 24, and 36 weeks after surgery. Clinical and histological evaluations were performed. Absorption rate was calculated by measuring the clip volume.
Results
Although the Mg alloy clips showed biodegradability over time, there were no significant differences in the serum concentration of Mg between the two groups. The remaining volume ratio of Mg alloy clips was 95.5, 94.3, 80.0, 36.2, and 16.7% at 1, 4, 12, 24, and 36 weeks, respectively. No side effects occurred. Most of the microscopic changes were similar in both groups.
Conclusions
The new biodegradable Mg alloy clips are safe and feasible in vessel ligation for hepatectomy in a rat model and reduce artifacts in CT imaging compared with the standard Ti clips.
Journal Article
Movie Description
Audio description (AD) provides linguistic descriptions of movies and allows visually impaired people to follow a movie along with their peers. Such descriptions are by design mainly visual and thus naturally form an interesting data source for computer vision and computational linguistics. In this work we propose a novel dataset which contains transcribed ADs, which are temporally aligned to full length movies. In addition we also collected and aligned movie scripts used in prior work and compare the two sources of descriptions. We introduce the
Large Scale Movie Description Challenge
(LSMDC) which contains a parallel corpus of 128,118 sentences aligned to video clips from 200 movies (around 150 h of video in total). The goal of the challenge is to automatically generate descriptions for the movie clips. First we characterize the dataset by benchmarking different approaches for generating video descriptions. Comparing ADs to scripts, we find that ADs are more visual and describe precisely what
is shown
rather than what
should happen
according to the scripts created prior to movie production. Furthermore, we present and compare the results of several teams who participated in the challenges organized in the context of two workshops at ICCV 2015 and ECCV 2016.
Journal Article
Video clips in physics education
Film recordings – video clips – have been used in the teaching and learning processes for decades. At the very beginning, the dominant role was played by television and professionally prepared recordings on portable media (e.g. LaserDiscs). With the advancement of technology and the emergence of new media, as well as the revolution in access to image and sound recording and processing devices, video clips – including amateur ones – have become the dominant path of contemporary visual communication. The paper is of an overview character and discusses examples of educational use of video in physics education in the past and at present, including TV lectures, popular science programs, dedicated video materials and educational environments, software for video measurement and evaluation of learning outcomes. Various illustrations along with literature references are given to outline potential educational pathways in making use of video clips as didactically valuable medium in teaching - learning physics.
Journal Article
AI for conceptual architecture: Reflections on designing with text-to-text, text-to-image, and image-to-image generators
In this paper we present a research-through-design study where we employed text-to-text, text-to-image, and image-to-image generative tools for a conceptual architecture project for the eVolo skyscraper competition. We trained these algorithms on a dataset that we collected and curated, consisting of texts about and images of architecture. We describe our design process, present the final proposal, reflect on the usefulness of such tools for early-stage design, and discuss implications for future research and practice. By analysing the results from training the text-to-text generators we could establish a specific design brief that informed the final concept. The results from the image-to-image generator gave an overview of the shape grammars of previous submissions. All results were intriguing and can assist creativity and in this way, the tools were useful for gaining insight into historical architectural data, helped shape a specific design brief, and provoked new ideas. By reflecting on our design process, we argue that the use of language when employing such tools takes a new role and that three layers of language intertwined in our work: architectural discourse, programming languages, and annotations. We present a map that unfolds how these layers came together as a contribution to making machine learning more explainable for creatives.
Journal Article
How to Flip the Classroom - ＂Productive Failure or Traditional Flipped Classroom＂ Pedagogical Design?
The paper reports a quasi-experimental study comparing the ＂traditional flipped classroom＂ pedagogical design with the ＂productive failure＂ (Kapur, 2016) pedagogical design in the flipped classroom for a 2-week curricular unit on polynomials in a Hong Kong Secondary school. Different from the flipped classroom where students are provided video clips with new concepts and associated procedures to review at home before solving problems in class, the ＂productive failure＂ pedagogical design in the flipped classroom worked the other way around. Supported by mobile technologies, students explored, discussed and solved problems related to the new concepts first in class even though they might come across failures, followed by consolidating the concepts and associated procedures using video clips at home. The pedagogical design is referred to as ＂productive failure-based flipped classroom＂ in this study. The study was carried out in two Grade 7 classes: one with ＂traditional flipped classroom＂ and one with the ＂productive failure-based flipped classroom＂. Findings show that both classes had significant improvement in procedural knowledge. However, regarding conceptual knowledge, students in the ＂productive failure＂ condition performed better than those in traditional flipped classroom. This suggests that the ＂productive failure-based flipped classroom＂ pedagogical design may be better able to improve students' problem solving skills.
Journal Article
Impact of Traction Direction in Traction-Assisted Gastric Endoscopic Submucosal Dissection (with Videos)
BackgroundThe impact of traction direction in traction-assisted gastric endoscopic submucosal dissection (ESD) has not been adequately investigated. A clip with line (CWL) is a classical single-directional traction device. In contrast, a spring and loop with clip (SLC; S–O clip) is a newly developed multidirectional traction device.AimsTo investigate the impact of traction direction in gastric ESD by comparing the procedure-related outcomes of CWL-assisted ESD (CWL-ESD) and SLC-assisted ESD (SLC-ESD).MethodsWe retrospectively examined 140 patients with superficial gastric neoplasms who underwent SLC-ESD or CWL-ESD by a single ESD expert during November 2017–September 2020. The traction direction was classified based on the endoscopic finding in the following five categories: proximal, diagonally proximal, vertical, diagonally distal, and distal. In SLC-ESD, we set vertical traction, using the multidirectional traction function. Propensity score matching was conducted to compensate for the differences in lesion size, injection function of electrosurgical knife, ulcerative lesion, lesion location, and lesion position. The primary outcome was gastric ESD procedure time.ResultsPropensity score matching created 42 pairs. The median gastric ESD procedure time in the SLC-ESD group was significantly shorter than that in the CWL-ESD group (28.3 min vs. 51.0 min, P = 0.022). All traction direction in the SLC-ESD group was vertical, while only 16.7% in the CWL-ESD group. En bloc resection was attained without perforation in all the patients in both groups.ConclusionOur findings suggest that SLC can provide vertical traction, which reduces the gastric ESD procedure time.Multidirectional traction devices can provide vertical traction in most cases of gastric ESD, unlike single-directional traction devices. Vertical traction may reduce the gastric ESD procedure time.
Journal Article