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Search Results: 1 - 10 of 210258 matches for " Henrik L. Funke "
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Function-Integrative Textile Reinforced Concrete Shells  [PDF]
Sandra Gelbrich, Henrik L. Funke, Lothar Kroll
Open Journal of Composite Materials (OJCM) , 2018, DOI: 10.4236/ojcm.2018.84013
Abstract:
This paper presents the development and technological implementation of textile reinforced concrete (TRC) shells with integrated functions, such as illumination and light control. In that regard the establishment of material, structural and technological foundations along the entire value chain are of central importance: From the light-weight design idea to the demonstrator and reference object, to the technological implementation for the transfer of the research results into practice. The development of the material included the requirement-oriented composition of a high-strength fine grained concrete with an integrated textile reinforcement, such as carbon knitted fabrics. Innovations in formwork solutions provide new possibilities for concrete constructions. So, a bionic optimized shape of the pavilion was developed, realized by four connected TRC-lightweight-shells. The thin-walled TRC-shells were manufactured with a formwork made of glass-fibre reinforced polymer (GFRP). An advantage of the GFRP-formwork is the freedom of design concerning the formwork shape. Moreover, an excellent concrete quality can be achieved, while the production of the precast concrete components is simple and efficient simultaneously. After the production the new TRC-shells were installed and assembled on the campus of TU-Chemnitz. A special feature of the research pavilions are the LED light strips integrated in the shell elements, providing homogeneous illumination.
Unsymmetrical Fibre-Reinforced Plastics for the Production of Curved Textile Reinforced Concrete Elements  [PDF]
Henrik L. Funke, Sandra Gelbrich, Andreas Ehrlich, Lars Ulke-Winter, Lothar Kroll
Open Journal of Composite Materials (OJCM) , 2014, DOI: 10.4236/ojcm.2014.44021
Abstract: A new constructive and technological approach was developed for the efficient production of large-dimensioned, curved freeform formworks, which allow the manufacturing of single and double-curved textile reinforced concrete elements. The approach is based on a flexible, multi-layered formwork system, which consists of glass-fibre reinforced plastic (GFRP). Using the unusual structural behavior caused by anisotropy, these GFRP formwork elements permit a specific adjustment of defined curvature. The system design of the developed GFRP formwork and the concrete-lightweight-elements with stabilized spacer fabric was examined exhaustively. Prototypical curved freeform surfaces with different curvature radii were designed, numerically computed and produced. Furthermore, the fabric’s contour accuracy of the fabric was verified, and its integration was adjusted to loads.
An Alkali Activated Binder for High Chemical Resistant Self-Leveling Mortar  [PDF]
Henrik L. Funke, Sandra Gelbrich, Lothar Kroll
Open Journal of Composite Materials (OJCM) , 2016, DOI: 10.4236/ojcm.2016.64013
Abstract: This paper reports the development of an Alkali Activated Binder (AAB) with an emphasis on the performance and the durability of the AAB-matrix. For the development of the matrix, the reactive components granulated slag and coal fly ash were used, which were alkali activated with a mixture of sodium hydroxide (2 - 10 mol/l) and aqueous sodium silicate solution (SiO2/Na2O molar ratio: 2.1) at ambient temperature. A sodium hydroxide concentration of 5.5 mol/l revealed the best compromise between setting time and mechanical strengths of the AAB. With this sodium hydroxide concentration, the compressive and the 3-point bending tensile strength of the hardened AAB were 53.4 and 5.5 MPa respectively after 14 days. As a result of the investigation of the acid resistance, the AAB-matrix showed a very high acid resistance in comparison to ordinary Portland cement concrete. In addition, the AAB had a high frost resistance, which had been validated by the capillary suction, internal damage and freeze thaw test with a relative dynamic E-Modulus of 93% and a total amount of scaled material of 30 g/m2 after 28 freeze-thaw cycles (exposure class: XF3).
A new 3-D modelling method to extract subtransect dimensions from underwater videos
L. Fillinger,T. Funke
Ocean Science (OS) & Discussions (OSD) , 2013, DOI: 10.5194/os-9-461-2013
Abstract: Underwater video transects have become a common tool for quantitative analysis of the seafloor. However a major difficulty remains in the accurate determination of the area surveyed as underwater navigation can be unreliable and image scaling does not always compensate for distortions due to perspective and topography. Depending on the camera set-up and available instruments, different methods of surface measurement are applied, which make it difficult to compare data obtained by different vehicles. 3-D modelling of the seafloor based on 2-D video data and a reference scale can be used to compute subtransect dimensions. Focussing on the length of the subtransect, the data obtained from 3-D models created with the software PhotoModeler Scanner are compared with those determined from underwater acoustic positioning (ultra short baseline, USBL) and bottom tracking (Doppler velocity log, DVL). 3-D model building and scaling was successfully conducted on all three tested set-ups and the distortion of the reference scales due to substrate roughness was identified as the main source of imprecision. Acoustic positioning was generally inaccurate and bottom tracking unreliable on rough terrain. Subtransect lengths assessed with PhotoModeler were on average 20% longer than those derived from acoustic positioning due to the higher spatial resolution and the inclusion of slope. On a high relief wall bottom tracking and 3-D modelling yielded similar results. At present, 3-D modelling is the most powerful, albeit the most time-consuming, method for accurate determination of video subtransect dimensions.
A new 3-D-modelling method to extract subtransect dimensions from underwater videos
L. Fillinger,T. Funke
Ocean Science Discussions (OSD) , 2012, DOI: 10.5194/osd-9-3879-2012
Abstract: Underwater video transects have become a common tool for quantitative analysis of the seafloor. However a major difficulty remains in the accurate determination of the area surveyed as underwater navigation can be unreliable and image scaling does not always compensate for distortions due to perspective and topography. Depending on the camera setup and available instruments, different methods of surface measurement are applied which make it difficult to compare data obtained by different vehicles. 3-D modelling of the seafloor based on 2-D video data and a reference scale can be used to compute subtransects dimensions. Focussing on the length of the subtransect, the data obtained from 3-D models created with the software PhotoModeler Scanner are compared with those determined from underwater acoustic positioning (Ultra-Short BaseLine – USBL) and bottom tracking (Doppler Velocity Log – DVL). 3-D models building and scaling was successfully conducted on all three tested setups while the distortion of the reference scales due to substrate roughness was identified as the main source of imprecision. Acoustic positioning was generally inaccurate and DVL unreliable on rough terrain. Subtransect lengths assessed with PhotoModeler were on average 20% longer than those derived from the USBL due to the higher spatial resolution and the inclusion of slope. On a high relief wall, DVL and 3-D modelling yielded similar results. At present, 3-D modelling is the most powerful, albeit the most time-consuming, method for the accurate determination of video subtransect dimensions.
Evaluation of Nutrient Contents of Amaranth Leaves Prepared Using Different Cooking Methods  [PDF]
Olumakaiye M. Funke
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.24035
Abstract: Amaranth is a commonly consumed vegetable in households in Southwestern Nigeria. Raw amaranth is known to be rich in micronutrients particularly Iron and Vitamin C, which are lost during cooking due to the method of preparation. Hence, this study was conducted to determine the method of preparation that best retains nutrients. Three common methods of preparing amaranth were identified; method 1 in which no heat was applied but amaranth leaves were finely chopped (samples A), method 2 which was steaming before chopping the leaves (sample B) and method 3 involved chopping of leaves before blanching (sample C). These three samples were subjected to proximate analysis and micronutrient determinations. Results were mean of three determinations. Result of proximate analysis showed that sample B method of preparation has highest percentage of crude fat per gram of sample (2.31 ± 0.45), protein (4.35 ± 0.15) and fibre (1.09 ± 0.06). Sample A has highest percentage of moisture (90.35 ± 0.27) and ash content (1.36 ± 0.28) while sample C has highest percentage per gram of sample in carbohydrate (4.89 ± 1.21) only. Micronutrient determination results showed that sample A was highest in Vitamin C (1.57 mg ± 0.06) and Iron (535.84 ppm ± 123.42), followed by sample C (1.21 ± 0.07) and (501.88 ± 215.19) respectively while sample B had the least vitamin C (0.79 ± 0.06) and Iron (354.18 ± 121.84). The study showed that samples A best retained the nutrient contents of Amaranth leaves after preparation.
Inverses of gamma functions
Henrik L. Pedersen
Mathematics , 2013,
Abstract: Euler's Gamma function $\Gamma$ either increases or decreases on intervals between two consequtive critical points. The inverse of $\Gamma$ on intervals of increase is shown to have an extension to a Pick-function and similar results are given on the intervals of decrease, thereby answering a question by Uchiyama. The corresponding integral representations are described. Similar results are obtained for a class of entire functions of genus 2, and in particular integral representations for the double gamma function and the $G$-function of Barnes are found.
Hybrid global-local optimisation algorithms for the layout design of tidal turbine arrays
George L. Barnett,Simon W. Funke,Matthew D. Piggott
Mathematics , 2014,
Abstract: Tidal stream power generation represents a promising source of renewable energy. In order to extract an economically useful amount of power, tens to hundreds of tidal turbines need to be placed within an array. The layout of these turbines can have a significant impact on the power extracted and hence on the viability of the site. Funke et al. formulated the question of the best turbine layout as an optimisation problem constrained by the shallow water equations and solved it using a local, gradient-based optimisation algorithm. Given the local nature of this approach, the question arises of how optimal the layouts actually are. This becomes particularly important for scenarios with complex bathymetry and layout constraints, both of which typically introduce locally optimal layouts. Optimisation algorithms which find the global optima generally require orders of magnitude more iterations than local optimisation algorithms and are thus infeasible in combination with an expensive flow model. This paper presents an analytical wake model to act as an efficient proxy to the shallow water model. Based upon this, a hybrid global-local two-stage optimisation approach is presented in which turbine layouts are first optimised with the analytical wake model via a global optimisation algorithm, and further optimised with the shallow water model via a local gradient-based optimisation algorithm. This procedure is applied to a number of idealised cases and a more realistic case with complex bathymetry in the Pentland Firth, Scotland. It is shown that in cases where bathymetry is considered, the two-stage optimisation procedure is able to improve the power extracted from the array by as much as 25% compared to local optimisation for idealised scenarios and by as much as 12% for the more realistic Pentland Firth scenario whilst in many cases reducing the overall computation time by approximately 35%.
Benefits of laptop computer ergonomics education to graduate students  [PDF]
Peter J. Bowman, Katharine D. Braswell, Jessica R. Cohen, Jenna L. Funke, Hannah L. Landon, Paloma I. Martinez, Julie N. Mossbarger
Open Journal of Therapy and Rehabilitation (OJTR) , 2014, DOI: 10.4236/ojtr.2014.21006
Abstract: Laptop computers are used more often than desktop computers, especially among graduate students. Many common laptop habits can have severe physiological effects on the user ranging from eye strain, poor posture, upper extremity pain, and overuse injuries. Thus, it is important to educate students on the best ergonomic position to use laptops. This study investigates the efficacy of a laptop ergonomic education session and its effects on graduate students’ knowledge and behaviors regarding proper laptop use. A convenience sample of control and experimental groups was used and consisted of 83 occupational therapy (OT), 63 physical therapy (PT), and 26 nurse anesthesia (NA) graduate students. The sample size was 172, with 94 graduate students in the control group and 78 graduate students in the experimental. All study participants completed an initial ergonomics questionnaire. The experimental group was given an ergonomics education session following the questionnaire. Approximately 4 weeks after both groups completed the initial questionnaire; a follow up questionnaire was administered. Results showed that subjects demonstrated a statistically significant improvement in ergonomics knowledge after they completed the ergonomic educational session. Some participants reported making adaptations to laptop positioning and equipment use following the educational session. Thus, participating in ergonomic education can positively influence awareness of body mechanics relative to laptop workstation design.
Heat Shock Proteins in the Human Eye
L?rke Urbak,Henrik Vorum
International Journal of Proteomics , 2010, DOI: 10.1155/2010/479571
Abstract: Heat shock proteins (Hsps) are believed to primarily protect and maintain cell viability under stressful conditions such as those occurring during thermal and oxidative challenges chiefly by refolding and stabilizing proteins. Hsps are found throughout the various tissues of the eye where they are thought to confer protection from disease states such as cataract, glaucoma, and cancer. This minireview summarizes the placement, properties, and roles of Hsps in the eye and aims to provide a better comprehension of their function and involvement in ocular disease pathogenesis. 1. Introduction In order to maintain the health of a cell, it is crucial to preserve the integrity of its proteins. The differing ocular cell types have specific mechanisms that facilitate proper folding of proteins, refolding of partly folded or misfolded proteins, and the disposal of irreversibly damaged proteins. Indeed, the heat shock proteins (Hsps), which act as molecular chaperones are extremely important contributors to these crucial cellular protein processes [1]. These molecular chaperones, which are expressed under normal conditions in the eye may be significantly upregulated with elevated temperatures or other stresses [2]. Hsps are primarily divided into groups according to their molecular mass prior to further subdivision. For example, Groenen et al. [3] classify Hsps into four groups: small Hsps, Hsp60, Hsp70, and Hsp90 where the numbers refer to the molecular mass in kilodaltons. Others have divided Hsps into seven groups: small Hsps, Hsp40, Hsp60, Hsp70, Hsp90, Hsp100, and large Hsps [4, 5]. In response to an ocular stress or injury, Hsp expression in the eye may be increased in order to possibly provide a cytoprotective action by facilitating the refolding of damaged proteins for instance [6]. This response, which can occur acutely or chronically, has been shown to be induced by a number of ways that include elevated temperatures [5], ischemia [7], osmotic stress [8], and oxidative stress [9]. The ocular heat shock response is activated by Heat Shock Factors (HSFs) (Figure 1) that are divided into groups of which HSF1 is the best studied. When stress is induced in the cells of the eye, HSF relocalizes to the nucleus, forming a granule-like structure [10] and binds with high affinity to Heat Shock Elements (HSEs) that are placed in the promoter region of the target gene, which promotes transcription of Hsps [11]. Thereby, the regulation of the ocular heat shock response is essentially regulated at the transcriptional level by the activities of HSF. In addition, HSF1
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