In the high-tech mechatronics world, aluminum and steel are well known materials, while carbon fiber is often neglected. In the RAAK project 'Composites in Mechatronics', the use of carbon fiber composites in mechatronics is investigated.
DOCUMENT
The present study deals with the numerical modelling of hybridlaminated composites, which can be proved especially useful in theengineering and maintenance of advanced aerospace primary structures. Thelamina is comprised of continuous carbon fibers, thermosetting epoxypolymer matrix, as well as carbon nanostructures, such as graphene orcarbon nanotubes, inclusions. Halpin-Tsai equations combined with resultsobtained from nanomechanical analysis are employed in order to evaluatethe elastic properties of the carbon nanostructure/polymer matrix. Then, theobtained elastic properties of the hybrid matrix are used to calculate theorthotropic macro-mechanical properties of the unidirectional compositelamina. A hybrid composite plate is modelled as a 2D structure via theutilization of 4-node, quadrilateral, stress/displacement shell finite elementswith reduced integration formulation. The convergence and analysisaccuracy are tested. The mechanical performance of the hybrid compositesis investigated by considering specific configurations and applyingappropriate loading and boundary conditions. The results are compared withthe corresponding ones found in the open literature, where it is possible.
DOCUMENT
Stricter environmental policies, increased energy prices and depletion of resources are forcing industries to look for bio-based and low carbon footprint products. For industries, flax is interesting resource since it is light, strong, environmental friendly and renewable. From flax plant to fiber products involves biochemical and mechanical processes. Moreover, production and processing costs have to compete with other products, like petroleum based materials. This research focusses on sustainable process improvement from flax plant to fiber production. Flax retting is a biological process at which mainly pectin is removed. Without retting, the desired fibre remains attached to the wooden core of the flax stem. As a result, the flax fibres cannot be gained, or have a lows quality. After retting, the fibers are released from the wooden core. Furthermore, machines have been introduced in the flax production process, but the best quality fibers are still produced manually. Due to the high labor intensity the process is too expensive and the process needs to be economical optimized. Since the retting process determines all other downstream processes, retting is the first step to focus on. Lab-scale experiments were performed to investigate the retting process. Factors that were researched were low cost processing conditions like, temperature, pH, dew retting and water retting. The retting rate was low, around three weeks for complete retting. The best retting conditions were at 20°C with water and any addition of chemicals. The process could be shortened to two weeks by recycling the water phase. In a scale-up experiment, a rotating drum was used at the optimal conditions from the lab-experiment (20°C and water). First the flax did not mix with the water content in the rotating drum. The flax was too rigid and did not tumble. Therefore, bundles of flax plants were used. The inner core of the bundle seemed to be protected and the retting rate was less compared to the flax on the surface of the flax bundle. This implies that mechanical impact increased retting in the rotating drum, however heterogeneous retting should be avoided. To overcome the heterogeneous retting problem, a water column was used to improve heterogeneous retting. Retting was performed in a water column and mixing was accomplished by bubbling air. As a result of the mixing, the flax bundle was retted homogenously. And after drying, it was possible to separate the fibers from the wooden flax core. Retting with a bubble column can overcome this problem and seems to be a usable retting process step. Water samples of the lab-scale experiments, the rotating drum and the bubble column showed a chemical oxygen demand (COD) content up to 4 g/L. Overall, 1 kg Flax resulted in 40 g COD. This indicates the possibility to produce biogas that can be used for generating heat and electricity, to make the process sustainable. Around 50% of the weight consists of wooden shives. The shives can be used for pyrolysis and it was possible to produce around 30% coal and 20% oil. These compounds can be used as building blocks, but also to generate heat and electricity. Heat and electricity can be used for the flax processing. Shives were only dried for 1 day at 105°C and slow pyrolysis was used. This indicates that a higher yield can be expected at fast pyrolysis. Overall, the reported implicates that quality fiber production from flax plant can be a feasible, sustainable and a renewable production process. Feasibility of the process can be obtained by, (1) retting at low-cost process conditions of 20°C and using water without any addition of chemicals, (2) with increased flax retting rate by recycling water, (3) with increased flax retting rate by introducing mixing forces, and the ability to lower the energy consumption of the overall process, (4) producing biogas from the COD with anaerobic digestion and (5) producing pyrolysis oil and pyrolysis c
MULTIFILE
Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l-glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l-glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.
MULTIFILE
The prediction of mechanical elastic response of laminated hybrid polymer composites with basic carbon nanostructure, that is carbon nanotubes and graphene, inclusions has gained importance in many advanced industries like aerospace and automotive. For this purpose, in the current work, a hierarchical, four-stage, multilevel framework is established, starting from the nanoscale, up to the laminated hybrid composites. The proposed methodology starts with the evaluation of the mechanical properties of carbon nanostructure inclusions, at the nanoscale, using advanced 3D spring-based finite element models. The nanoinclusions are considered to be embedded randomly in the matrix material, and the Halpin-Tsai model is used in order to compute the average properties of the hybrid matrix at the lamina micromechanics level. Then, the standard Halpin-Tsai equations are employed to establish the orthotropic elastic properties of the unidirectional carbon fiber composite at the lamina macromechanics level. Finally, the lamination theory is implemented in order to establish the macroscopic force-strain and moment-curvature relations at the laminate level. The elastic mechanical properties of specific composite configurations and their performance in different mechanical tests are evaluated using finite element analysis and are found to considerably increase with the nanomaterial volume fraction increase for values up to 0.5. Further, the hybrid composite structures with graphene inclusions demonstrate better mechanical performance as compared to the identical structures with CNT inclusions. Comparisons with theoretical or other numerical techniques, where it is possible, demonstrate the accuracy of the proposed technique.
DOCUMENT
Dit Tech-Info-blad is tot stand gekomen binnen het kader van het kennisoverdrachtproject "Fabricage van producten met geavanceerde productiemiddelen voor het omvormen en verbinden - FPGP". In dit kader zijn ook de volgende publicaties uitgegeven: TI.07.37 - "Laserlassen van complexe producten" en TI.07.38 - "Geautomatiseerd buigen". Uitgebreide informatie betreffende het laserlassen is tevens te vinden op de websites www.dunneplaat-online.nl en www.verbinden-online.nl, waarop tevens de volgende relevante Tech-Info-bladen vrij gedownload kunnen worden: TI.99.08 - "Laserlassen van beklede plaat", TI.00.11 - "Oppervlaktebehandelingen met de laser (cladden, legeren en dispergeren)", TI.00.12 - "Laser- en waterstraalsnijden van gelamineerde en beklede plaat", TI.07.34 - "Laserlassen vs. conventionele lastechnieken", TI.07.35 - "Omvormen", IOP 7.2 - "Lasertransformatieharden", alsmede de praktijkaanbeveling PA.02.13 - "Oppervlaktebewerkingen met hoogvermogen lasers".
DOCUMENT
The increasing rate of urbanization along with its socio-environmental impact are major global challenges. Therefore, there is a need to assess the boundaries to growth for the future development of cities by the inclusion of the assessment of the environmental carrying capacity (ECC) into spatial management. The purpose is to assess the resource dependence of a given entity. ECC is usually assessed based on indicators such as the ecological footprint (EF) and biocapacity (BC). EF is a measure of the biologically productive areas demanded by human consumption and waste production. Such areas include the space needed for regenerating food and fibers as well as sequestering the generated pollution, particularly CO2 from the combustion of fossil fuels. BC reflects the biological regeneration potential of a given area to regenerate resources as well to absorb waste. The city level EF assessment has been applied to urban zones across the world, however, there is a noticeable lack of urban EF assessments in Central Eastern Europe. Therefore, the current research is a first estimate of the EF and BC for the city of Wrocław, Poland. This study estimates the Ecological Footprint of Food (EFF) through both a top-down assessment and a hybrid top-down/bottom-up assessment. Thus, this research verifies also if results from hybrid method could be comparable with top-down approach. The bottom-up component of the hybrid analysis calculated the carbon footprint of food using the life cycle assessment (LCA) method. The top-down result ofWrocław’s EFF were 1% greater than the hybrid EFF result, 0.974 and 0.963 gha per person respectively. The result indicated that the EFF exceeded the BC of the city of Wrocław 10-fold. Such assessment support efforts to increase resource efficiency and decrease the risk associated with resources—including food security. Therefore, there is a need to verify if a city is able to satisfy the resource needs of its inhabitants while maintaining the natural capital on which they depend intact. Original article at: https://doi.org/10.3390/resources7030052 © 2018 by the authors. Licensee MDPI.
MULTIFILE
Urban tourism increasingly focuses on the role of hospitality in cities, evolving from a means to strengthen tourism as a ‘product’, towards a focus on tourism as an opportunity for revitalization and transformation of destinations. In this context, cities are considered dynamic communities in which ‘hosts’ (entrepreneurs, residents, municipalities) and ‘guests’ (visitors, tourists) co-habitate and co-create multisensorial experiences. This shift in focus comes hand in hand with increasing awareness of competitiveness and sustainability of destinations, expressed by a harmonious relationship between city residents and visitors and a balanced usage of the city as a shared resource. This is of great importance, given the intense usage of urban spaces – the city center of Amsterdam being an illustrative example – and the multiple purposes that these spaces represent for different stakeholders. This paper presents the outcome of a review study into city hospitality experience indicators. We integrate these indicators as a basis for the development of a new scale for measuring the effectiveness of hospitality interventions in relation to outcome variables such as satisfaction and net promotor score (NPS). We thereby provide an important means for scholars and practitioners to develop sustainable tourism actions inclusive of local community interests, in support of efforts toward more balanced city experiences among all stakeholders.
DOCUMENT
This chapter will introduce the circular economy (CE) and Cradle to Cradle (C2C) models of sustainable production. It will reflect on the key blockages to a meaningful sustainable production and how these could be overcome, particularly in the context of business education. The case study of the course for bachelor’s students within International Business Management Studies (IBMS), and at University College in The Netherlands will be discussed. These case studies will illustrate the opportunities as well as potential pitfalls of the closed loop production models. The results of case studies’ analysis show that there was a mismatch between expectations of the sponsor companies and those of students on the one hand and a mismatch between theory and practice on the other hand. Helpful directions for future research and teaching practice are outlined. https://www.springer.com/gp/book/9783319713113#aboutBook https://www.linkedin.com/in/helenkopnina/
MULTIFILE
Introduction: Besides dyspnoea and cough, patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis may experience distressing non-respiratory symptoms, such as fatigue or muscle weakness. However, whether and to what extent symptom burden differs between patients with IPF or sarcoidosis and individuals without respiratory disease remains currently unknown. Objectives: To study the respiratory and non-respiratory burden of multiple symptoms in patients with IPF or sarcoidosis and to compare the symptom burden with individuals without impaired spirometric values, FVC and FEV1 (controls). Methods: Demographics and symptoms were assessed in 59 patients with IPF, 60 patients with sarcoidosis and 118 controls (age ≥18 years). Patients with either condition were matched to controls by sex and age. Severity of 14 symptoms was assessed using a Visual Analogue Scale. Results: 44 patients with IPF (77.3% male; age 70.6±5.5 years) and 44 matched controls, and 45 patients with sarcoidosis (48.9% male; age 58.1±8.6 year) and 45 matched controls were analyzed. Patients with IPF scored higher on 11 symptoms compared to controls (p<0.05), with the largest differences for dyspnoea, cough, fatigue, muscle weakness and insomnia. Patients with sarcoidosis scored higher on all 14 symptoms (p<0.05), with the largest differences for dyspnoea, fatigue, cough, muscle weakness, insomnia, pain, itch, thirst, micturition (night, day). Conclusions: Generally, respiratory and non-respiratory symptom burden is significantly higher in patients with IPF or sarcoidosis compared to controls. This emphasizes the importance of awareness for respiratory and non-respiratory symptom burden in IPF or sarcoidosis and the need for additional research to study the underlying mechanisms and subsequent interventions.
DOCUMENT
