Hochschule fur Angewandte Wissenschaften

Hamburg, Germany

Hochschule fur Angewandte Wissenschaften

Hamburg, Germany

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Raj P.,Virginia Polytechnic Institute and State University | Abulawi J.,Hochschule fur Angewandte Wissenschaften
30th Congress of the International Council of the Aeronautical Sciences, ICAS 2016 | Year: 2016

Virginia Tech in USA and HAW in Germany jointly embarked on a journey in the fall of 2013 with the goal of better preparing our students to succeed in the emerging marketplace created by the increasing globalization of the aerospace enterprise. To accomplish this goal, we needed to enhance the undergraduate educational environment by providing the students, on both sides of the Atlantic, an opportunity to learn about the associated challenges first hand while immersing themselves in the design discipline. The expectation was that the participating students would learn to (a) effectively communicate with people separated by time zones, languages, cultures and educational backgrounds, (b) leverage strengths of a diverse set of teammates, and (c) successfully complete the project by identifying and managing key risks. In this paper, the authors share lessons learned and insights gained based on three years of experience.

PubMed | Biosign GmbH, Hochschule fur Angewandte Wissenschaften and University of Heidelberg
Type: Journal Article | Journal: European journal of applied physiology | Year: 2016

We analyzed heart rate variability (HRV) taken by ECG and photoplethysmography (PPG) to assess their agreement. We also analyzed the sensitivity and specificity of PPG to identify subjects with low HRV as an example of its potential use for clinical applications.The HRV parameters: mean heart rate (HR), amplitude, and ratio of heart rate oscillation (E-I difference, E/I ratio), RMSSD, SDNN, and Power LF, were measured during 1-min deep breathing tests (DBT) in 343 individuals, followed by a 5-min short-term HRV (s-HRV), where the HRV parameters: HR, SD1, SD2, SDNN, Stress Index, Power HF, Power LF, Power VLF, and Total Power, were determined as well. Parameters were compared through correlation analysis and agreement analysis by Bland-Altman plots.PPG derived parameters HR and SD2 in s-HRV showed better agreement than SD1, Power HF, and stress index, whereas in DBT HR, E/I ratio and SDNN were superior to Power LF and RMSSD. DBT yielded stronger agreement than s-HRV. A slight overestimation of PPG HRV over HCG HRV was found. HR, Total Power, and SD2 in the s-HRV, HR, Power LF, and SDNN in the DBT showed high sensitivity and specificity to detect individuals with poor HRV. Cutoff percentiles are given for the future development of PPG-based devices.HRV measured by PPG shows good agreement with ECG HRV when appropriate parameters are used, and PPG-based devices can be employed as an easy screening tool to detect individuals with poor HRV, especially in the 1-min DBT test.

Petersen K.D.,Hochschule fur Angewandte Wissenschaften | Kleeberg K.K.,ODOCON GbR | Jahreis G.,Friedrich - Schiller University of Jena | Fritsche J.,Hochschule fur Angewandte Wissenschaften
International Journal of Food Sciences and Nutrition | Year: 2012

Headspace-solid-phase microextraction-gas chromatography (HS-SPME-GC) was used to identify in total 74 volatile lipid oxidation compounds altogether in thermally stressed conventional and high-oleic sunflower (HOSF) oil samples (in accelerated storage conditions for 14 days at 80°C). Out of the volatile compounds identified, six volatile compounds were selected as marker compounds for the assessment of lipid oxidation of sunflower (SF) and HOSF oils due to their low odour threshold values and fatty-rancid odour impression. Additionally, other oxidation parameters such as fatty acid composition, peroxide value (PV), anisidine value and tocopherol and tocotrienol composition were determined. Multivariate statistical methods (principal component analysis and agglomerative hierarchical cluster analysis) were applied to identify sensitive oxidation marker compounds. Preliminary results revealed that hexanal, E-2-heptenal, E-2-decenal and E,E-2,4-nonadienal were the most suitable in differentiating HOSF and SF oil varieties from each other and SF samples with differing oxidative properties. Differentiation of SF samples according to their volatile compound composition was done in accordance with the results from the well-known oil quality parameters (e.g. PV or fatty acid composition). In conclusion, the combination of volatile compound analysis with HS-SPME-GC and multivariate statistical methods provides a sensitive tool in differentiating conventional SF and HOSF oils by means of volatile lipid oxidation marker compounds. © 2011 Informa UK, Ltd.

Petersen K.D.,Hochschule fur Angewandte Wissenschaften | Kleeberg K.K.,ODOCON GbR | Jahreis G.,Friedrich - Schiller University of Jena | Busch-Stockfisch M.,Hochschule fur Angewandte Wissenschaften | Fritsche J.,Hochschule fur Angewandte Wissenschaften
European Journal of Lipid Science and Technology | Year: 2012

Headspace-solid-phase microextraction-gas chromatography was used to identify in total 55 volatile lipid oxidation compounds in thermally stressed conventional and high-oleic rapeseed oil samples. Out of this profile, 17 volatile compounds with low odor threshold values were selected as target compounds for the assessment of lipid oxidation in rapeseed and high-oleic rapeseed oils. Additionally, other lipid oxidation parameters such as fatty acid composition, peroxide value, anisidine value, and induction time (Rancimat analysis) were determined. Multivariate statistical methods (principal component analysis in combination with agglomerative hierarchical cluster analysis) were applied to identify sensitive volatile lipid oxidation indicators enabling the differentiation of rapeseed oil samples of different varieties (high-oleic versus conventional). Moreover, these statistical methods were capable of differentiating rapeseed oils of different oxidative properties. Octanal and 3-octanone showed the highest ability to differentiate between samples of different rapeseed varieties, whereas propanal, E,E-2,4-hexadienal, and E-2-heptenal were most suitable in differentiating rapeseed oil samples with different oxidative properties from each other. Clustering of rapeseed oil samples according to their volatile compound composition was comparable with results of sensory duo-trio and paired comparison tests, but the analytical approach of the volatile compound analysis in combination with chemometric methods detected changes sooner in relation to the flavor composition of rapeseed oils and high-oleic rapeseed oil samples. Practical applications: The combination of volatile compound analysis by HS-SPME-GC with multivariate statistical methods and complementary sensory duo-trio and one-sided paired comparison tests are sensitive tools in differentiating conventional and high-oleic rapeseed oil samples with different lipid oxidation properties. The presented methods are suitable techniques for the detection of initial changes of lipid oxidation progress in edible oils. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shapiro A.I.,World Radiation Center | Solanki S.K.,Max Planck Institute for Solar System Research | Solanki S.K.,Kyung Hee University | Krivova N.A.,Max Planck Institute for Solar System Research | And 6 more authors.
Astronomy and Astrophysics | Year: 2014

Context. The Sun and stars with low magnetic activity levels become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behavior and become fainter when their activity increases.Aims. We reproduce the observed photometric trends in stellar variations with a model thattreats stars as hypothetical suns with coverage by magnetic features different from that of the Sun.Methods. The model attributes the variability of stellar spectra to the imbalance between the contributions from different components of the solar atmosphere, such as dark starspots and bright faculae. A stellar spectrum is calculated from spectra of the individual components by weighting them with corresponding disk-area coverages. The latter are obtained by extrapolating the solar dependences of spot and facular disk-area coverages on chromospheric activity to stars with different levels of mean chromospheric activity.Results. We find that the contribution by starspots to the variability increases faster with chromospheric activity than the facular contribution. This causes the transition from faculae-dominated variability and direct activity-brightness correlation to spot-dominated variability and inverse activity-brightness correlation with increasing chromospheric activity level. We show that the regime of the variability also depends on the angle between the stellar rotation axis and the line-of-sight and on the latitudinal distribution of active regions on the stellar surface. Our model can be used as a tool for extrapolating the observed photometric variability of the Sun to Sun-like stars at different activity levels, which makes a direct comparison between solar and stellar irradiance data possible. © ESO, 2014.

Vogt C.,Hochschule Fur Angewandte Wissenschaften | Rohrbacher M.,Hochschule Fur Angewandte Wissenschaften | Sinzinger S.,TU Ilmenau
Proceedings of the 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013 | Year: 2013

Highly accurate pre-machining of optical parts using grinding processes is a challenge. A large range of parameters for optimisation is available, such as tool type, grit size, grit concentration, feed rate, cutting speed, depth of cut and grinding strategy. Several approaches for optimising and estimating grinding processes were developed - more or less successfully. A well known quantitative model for grinding processes is the average chipping thickness, described by several authors. The theoretical approach using this model is to calculate the chip height that a single grit would have to remove passing the contact layer between work piece and grinding tool. This model can be used to predict the characteristics of grinding processes - as long as tool wear is irrelevant. This goes especially for processes dealing with materials with lower hardness, e. g. BK7, and tools comprised of diamond grits and metal bonds. Grinding harder materials, such as ceramics, goes along with increased tool wear. It depends on the setup weather the average chipping model meets the reality. Research on active and passive dressing of grinding tools using a high resolution confocal microscope enabled the reconstruction of interactions, for a better understanding of the process. The gained data was used to develop a simple model for quantifying the sharpness of grinding tools. A procedure was developed to evaluate the condition of grinding tools. The results were verified by force measurements during grinding test runs. It was possible to monitore the wear process after dressing, until selfsharpening occurs in a periodical manner. A very interesting finding is the effect of different bond materials on the surface quality, as far as sub surface damages and roughness are concerned. The chipping process after active dressing and a certain tool wear has different characteristics. The bond material is involved in the chipping process, as soon as a certain level of tool wear is reached. Appropriate tool design enables the production of surface roughness from 200 nm Ra down to 10 nm Ra or even simple smoothing tools for creating surfaces with 10 nm Ra and below. The developed model explains different effects using similar specified tools with different bonds, e. g. metal, resin (soft, hard) or even ELID supported processes. This opens a new point of view for optimizing grinding tools.

Background: Patient education can contribute to obtaining and maintaining mobility in elderly with mobility impairments. The aim of this study was to evaluate counseling, training, and information needs in elderly patients with mobility impairments before, during, and after a hospital stay in a geriatric clinic. Methods: A prospective longitudinal study was conducted. Needs were assessed at admission (t1), after 2 weeks (t2), at discharge (t3), after 3 months (t4), and after 6 months (t5). Data were analyzed using descriptive statistics. Results: At almost all time points, there was a need of counseling and information. Counseling needs mainly comprised the themes assistive advices, fall prevention, professional nursing care, other services, nutrition, and pain management. Information needs comprised the themes fall prevention, professional nursing care, other services, assistive devices, nutrition, and modification of living space. There was a need of training mainly at admission and at discharge. Training needs comprised approach to assistive devices and mobility facilitation. Conclusion: Training should include activities related to mobility, while counseling and information should comprise all areas of life. © 2013 Springer-Verlag Berlin Heidelberg.

Kale N.V.,QualityPark AviationCenter GmbH | Ilkay F.,Hochschule fur Angewandte Wissenschaften | Zysk O.,QualityPark AviationCenter GmbH
International Journal of Structural Integrity | Year: 2015

Purpose - This document presents a Particular Risks Assessment (PRA) performed on an Uncontained Engine Rotor Failure (UERF) event for the new aircraft design hybrid Extremely Short Take Off and Landing All Surface (ESTOLAS) aircraft. All three propellers of the ESTOLAS (one hub propeller and two feed propellers) are evaluated for their impact on the aircraft in case of an UERF. The purpose of this paper is to present an illustration of the safety analysis and its requirement in new aircraft development. Design/methodology/approach - The methodology used is in accordance with the aerospace industry safety standard Society of Automobile Engineers (SAE) Aerospace Recommended Practices (ARP) 4,761 (Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment). Trajectory analyses are used on a digital mock-up of the aircraft to simulate the movement of the propeller blade fragments and its effect on the aircraft and its systems. Findings - The paper provides an insight into the industry practice of performing PRA on new aircraft designs. The study identifies safe and unsafe regions of the aircraft, with the UERF event in mind. Technical solutions are suggested to minimize the damage to the aircraft and its systems. Originality/value - This document fulfills the originality criterion, since it is an analysis performed on a new aircraft design - the ESTOLAS. ©Emerald Group Publishing Limited.

Lahn J.,match2blue | Peter H.,match2blue | Braun P.,Hochschule fur Angewandte Wissenschaften
ACM International Conference Proceeding Series | Year: 2015

In this paper we describe a simple car crash detection algorithm implemented on Android smartphones. The algorithm uses accelerometer sensor and location sensor information which are combined to detect typical patterns of car crash situations. We present technical details of our implementation and first results of an evaluation.

Krey M.,Hochschule fur Angewandte Wissenschaften | Riemschneider K.-R.,Hochschule fur Angewandte Wissenschaften | Zippel S.,Hochschule fur Angewandte Wissenschaften
2012 IEEE I2MTC - International Instrumentation and Measurement Technology Conference, Proceedings | Year: 2012

Magnetic sensors based on the AMR-effect are widely used as sensors in automotive applications. The wheel speed sensor signal is used by the Anti-Lock-Brake-System (ABS) and other electronic stability programs. These systems require very high availability of the wheel speed information and consequently the sensor function demands very strict reliability. The electrical output signal is the combination of a complex magnetic system and the nonlinear behaviour of the magnetoresistive sensor. Small deviations from the optimal sensor position in front of the encoder wheel cause signal distortions in the electrical output signal. Therefore the bridge behavior is very sensitive outside the center of a specified range, where the linearity is approximated in a sufficient manner. For reliability issues the knowledge of the real operating point is important. To investigate this we propose a method to synthesize a sensor signal in two steps: (1) simulate the mechanical-magnetic system originated from sensor in correspondence to encoder-wheel to deliver the relevant field strength functions (2) use a measured two-dimensional characteristic diagram as high-resolution look-up-array to convert from the relevant field strength to sensor voltages. Finally the resulting signals of the proposed synthesis are compared with physically measured signals from a high-precision positioning setup. © 2012 IEEE.

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