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In general, composite materials are difficult to recycle. Tires belong to this class of materials. On top, one of their main constitutents, vulcanized rubber, is as elastomer, which cannot be remolten and hence is particularly challenging to put to a new use. Today, the main end-of-life routes of tires and other rubber products are landfilling, incineration in e.g., cement plants, and grinding to a fine powder, generating huge quantities and indicating a lack of sustainable recycling of this valuable material. True feedstock recycling is not feasible for complex mixtures such as tires, but devulcanization can be done to reactivate the cross-linked polymer for material recycling in novel rubber products. Devulcanization, i.e., the breaking up of sulfur bonds by chemical, thermophysical, or biological means, is a promising route that has been investigated for more than 50 years. This review article presents an update on the state-of-the art in rubber devulcanization. The article addresses established devulcanization technologies and novel processes described in the scientific and patent literatures. On the one hand, tires have become high-tech products, where the simultaneous improvement of wet traction, rolling resistance, and abrasion resistance (the so-called “magic triangle”) is hard to achieve. On the other hand, recycling and sustainable end-of-life uses are becoming more and more important. It is expected that the public discussion of environmental impacts of thermoplastics will soon spill over to thermosets and elastomers. Therefore, the industry needs to develop and market solutions proactively. Every year, approximately 40 million tons of tires are discarded. Through the devulcanization of end-of-life tires (ELT), it is possible to produce new raw materials with good mechanical properties and a superior environmental footprint over virgin products. The devulcanization process has become an interesting technology that is able to support the circular economy concept.
Methane is the main greenhouse gas (GHG) emitted by ruminants. Mitigation strategies are required to alleviate this negative environmental impact while maintaining productivity and ruminants’ health. To date, numerous methane mitigation strategies have been investigated, reported and suggested by scientists to the livestock industry. In this review, the authors will focus on the commonly practiced and available techniques expanding the knowledge of the reader on the advances of methane mitigation strategies with a focus on the recent literature. Furthermore, the authors will attempt to discuss the drawbacks of the strategies in terms of animal health and performance reduction as well as the concept of feed and energy loss, adding an economic perspective to methane emission mitigation which is in the farmers’ direct interest. As a whole, many factors are effective in reducing undesired methane production, but this is definitely a complex challenge. Conclusively, further research is required to offer effective and efficient methane production mitigation solutions in ruminants worldwide, thus positively contributing to climate change.
This study aimed to assess the impact of essential oils (EOs) on in vitro gas formation and the degradability of dairy and beef cattle diets. This study also aimed to investigate the effects of different types of EOs on nutrient utilization and rumen microbial activity. The current study was conducted using a fully randomized design consisting of eight experimental treatments, including two control treatments without any additives, and treatments with cinnamon essential oil (CEO), flaxseed essential oil (FEO), and lemon seed essential oil (LEO) at a concentration of 60 mg/kg fresh mass. Two control treatments were used, one with alfalfa silage and dairy concentrate (DC, CON-DC) and the other with alfalfa silage and fattening concentrate (FC, CON-FC). Gas formation, dry matter (DM) digestibility, crude protein (CP) digestibility, effective degradability (ED), and soluble fractions of DM and organic matter (OM) were evaluated. CEO had a substantial effect on gas formation (p < 0.05). When EOs were added to the diets, they increased dry matter digestibility after 24 h of incubation as compared to control treatments. After 24 h of incubation, FCCEO and FCFEO had the highest CP digestibility among the diets. FCLEO considerably enhanced ED, as well as the soluble fraction of DM (a) at a passage rate of 2% per hour. Treatment with FCCEO resulted in a significant increase in soluble fractions compared to the control diets. At a passage rate of 2% h, DCCEO had the maximum ED value. When EOs were introduced to the diet, they dramatically decreased the insoluble portion of CP (b). Compared to the control treatments, gas production was significantly lower in the presence of LEO (FCLEO; p < 0.05). The addition of EOs to cattle diets may increase nutrient utilization and enhance rumen microbial activity. EOs extracted from lemon seeds (at a dose of 60 mg/kg of diet) lowered gas production in both dairy cattle and fattening diets.
Perspectives on Virtual Reality in Higher Education for Robotics and Related Engineering Disciplines
(2022)
Industrial engineering education has a strong focus on and affinity towards technology. While Virtual Reality hardware and applications advance and learning behaviour changes, it is particularly interesting to determine the possible use of Virtual Reality for teaching engineering subjects, for example fundamentals of robotics.
This paper presents a study which examines the possible use of Virtual Reality learning environments at higher learning institutions. The study shows perspectives of students and lecturers and identifies opportunities and challenges for the use of Virtual Reality in industrial engineering education. The results of the indicated study show that the participants have a positive attitude towards Virtual Reality and strong motivation for in class use. The study results also suggest, that Virtual Reality content creation should be included in engineering curricula.
In order to enhance the strength of 3D-printed parts made of polymer materials and reduce the anisotropy caused by the fused filament fabrication process, this paper proposes an inter-layer interleaved composite path planning method based on the directional partition of the principal stress field. This method not only ensures intra-layer reinforcement under specific working conditions but also increases the strength of the printed part by enhancing the adhesion of adjacent layers through staggered filling between layers. The mechanical performance is improved by 10 to 30% compared to other conventional filling patterns such as the zigzag filling algorithm. Inter-layer interleaved composite enhancement path planning method is suitable for path planning of structures with complex shapes and is easily integrated into existing general computer-aided engineering processes.
Engineering education courses look into processes, equipment and people in order to prepare students to tackle problems in their careers. In manufacturing industry, it is important to use virtual manufacturing tools to analyse processes. This includes both equipment and people. Assembly operations can involve human operators. Modular arrangements of predetermined time standards MODAPTS is a predetermined motion time system method used to analyse assembly processes. Augmented reality (AR) is increasingly being used for industrial processes as well as in education. AR application have been used for maintenance training as a useful way to overly digital instructions to a trainee whilst being able to look at a real object. This is potential beneficial for education. This paper presents the evaluation of a prototype to test a predetermined time standards model using an AR application. An evaluation was carried out comparing AR-based instructions in tablet and PC monitor and paper-written instructions. The results of evaluating the prototype encourage their use as an educational tool in engineering courses.
Diese Arbeit beschreibt eine Augmented Reality (AR) Applikation für den Einsatz in der Hochschullehre zum Thema Industrierobotik. Ziel ist es, sowohl das Lehren als auch das Lernen grundlegender Robotik-Inhalte durch die Bereitstellung einer interaktiven Methode zur Vermittlung der Lehrinhalte für Studierende zu verbessern. Die Studierenden sind in der Lage, direkt mit dem virtuellen Modell eines Industrieroboters zu interagieren und so selbstgesteuert die Lerninhalte zu vertiefen. Diese interaktive Methode verbindet die Studierenden direkt mit den Lehrinhalten und fördert das selbsterforschende Lernen. Eine weitere Anwendungsmöglichkeit sieht die Kombination einer Lektorenversion der AR Experience mit der Studierendenversion vor. Der Lektor hat die Möglichkeit, das Modell in AR zu steuern bzw. zu verändern und die Studierenden können auf Ihren Mobilgeräten die Änderungen live in AR mitverfolgen, um so auch im Distance Learning eine Verbindung Lektor – Studierende – Inhalt zusätzlich zu Videokonferenz-Tools herzustellen.
Talipot starch, a non-conventional starch source with a high yield (76%) from the stem pith of talipot palm (Corypha umbraculifera L.) was subjected to three different thermal treatments (dry-heat, heat-moisture and autoclave treatments) prior to phosphorylation. Upon dual modification of starch with thermal treatments and phosphorylation, the phosphorous content and degree of crosslinking significantly increased (p ≤ 0.05) and was confirmed by the increased peak intensity of P=O and P–O–C stretching vibrations compared to phosphorylated talipot starch in the FT-IR spectrum. The highest degree of crosslinking (0.00418) was observed in the autoclave pretreated phosphorylated talipot starch sample. Thermal pretreatment remarkably changed the granule morphology by creating fissures and grooves. The amylose content and relative crystallinity of all phosphorylated talipot starches significantly decreased (p ≤ 0.05) due to crosslinking by the formation of phosphodiester bonds, reducing the swelling power of dual-modified starches. Among all modified starches, dry-heat pretreated phosphorylated starch gel showed an improved light transmittance value of 28.4%, indicating reduced retrogradation tendency. Pasting and rheological properties represented that the thermal pretreated phosphorylated starch formed stronger gels that improved thermal and shear resistance. Autoclave treatment before phosphorylation of talipot starch showed the highest resistant starch content of 48.08%.