Fak. 5 Verkehrs- und Maschinensysteme

1137 Items

Recent Submissions
Control of secondary flow structures on a highly loaded compressor cascade

Zander, Vincent ; Nitsche, W. (2013)

This paper presents detailed flow-field measurements for a compressor cascade equipped with synthetic jet actuators for active flow control. The synthetic jets are mounted on the cascade sidewall and the suction side surface of the blade to reduce the total pressure loss caused by strong secondary flow structures developing in the passage. There are certain articles reporting that synthetic jet...

Active flow control by means of synthetic jets on a highly loaded compressor cascade

Zander, Vincent ; Hecklau, Martin ; Nitsche, W. ; Huppertz, A. ; Swoboda, M. (2011)

This article presents the potential of active flow control to increase the aerodynamic performance of highly loaded turbomachinery compressor blades. Experimental investigations on a large-scale compressor cascade equipped with 30 synthetic jet actuators mounted to the sidewalls and the blades themselves have been carried out. Results for a variation of the inflow angle, the jet amplitude, and ...

On the Relation Between Reliance and Compliance in an Aided Visual Scanning Task

Wiczorek, Rebecca ; Meyer, Joachim ; Günzler, Torsten (2012)

Alarms, alerts, and other binary cues affect user behavior in complex ways. One relevant distinction is the suggestion that there are two different responses to alerts – compliance (the tendency to perform an action cued by the alert) and reliance (the tendency to refrain from actions as long as no alert is issued). An experiment tested the dependence of the two behaviors on the Positive and Ne...

Benefits of Decision-Support by Likelihood versus Binary Alarm Systems

Wiczorek, Rebecca ; Manzey, Dietrich ; Zirk, Anna (2014)

Recent research has shown that the use of 3-stage likelihood alarm systems (LAS) has the potential to mitigate performance deficits associated with the use of binary alarm systems (BAS). The additional likelihood information can guide operators’ behavior and improve their decision-making accuracy. Comparisons of LAS with different numbers of stages are missing so far. Therefore, the current stu...

Supporting Attention Allocation in Multitask Environments

Wiczorek, Rebecca ; Manzey, Dietrich (2014)

Objective: The aim of the current study was to investigate potential benefits of likelihood alarm systems (LASs) over binary alarm systems (BASs) in a multitask environment. Background: Several problems are associated with the use of BASs, because most of them generate high numbers of false alarms. Operators lose trust in the systems and ignore alarms or cross-check all of them when other info...

Is Operators' Compliance with Alarm Systems a Product of Rational Consideration?

Wiczorek, Rebecca ; Manzey, Dietrich (2010)

Most theories about operators' responses to alarm systems suggest that the operators' behavior is guided by their trust towards the system which in turn results from the subjective perception of system properties, namely the perceived reliability of the alarm system. However, some doubts about that assumption have arisen as recent research has not proven the mediating effect of trust. The purpo...

Studies on conventional cutting of intermetallic nickel and titanium aluminides

Uhlmann, Eckart ; Herter, S. (2006)

Owing to the high percentage of covalent bonds, intermetallic nickel and titanium aluminides have specific physical and chemical characteristics that predestine them for components under high thermal and mechanical load. However, the relatively low ductility and thermal conductivity at room temperature, linked to high tensile strength, impede the machining with geometrically defined cutting edg...

Monitoring of slowly progressing deterioration of computer numerical control machine axes

Uhlmann, Eckart ; Geisert, C. ; Hohwieler, E. (2008)

The feed axes of computer numerical control (CNC) grinding machine tools are among the most mechanically stressed components of machine tools owing to the high process forces and rough manufacturing environment which they encounter. The resulting wear and tear depends strongly on the product range and the manner of machine operation. To counteract a functional deficiency of these central machin...

Innovative manufacturing technologies for the disassembly of consumer goods

Uhlmann, Eckart ; Elbing, F. ; Dittberner, J. (2004)

Ecological harmless disposal of used technical consumer products will become mandatory for producers and importing companies. This disposal policy will focus on product and material loops; used products will be disassembled and the parts and materials then recycled. Owing to environmental and legislative reasons, the importance of disassembly as a step in the process of recycling is steadily ri...

Non-linear investigation of an asymmetric disk brake model

Spelsberg-Korspeter, G. ; Hochlenert, Daniel ; Hagedorn, P. (2011)

Among design engineers, it is known that breaking symmetries of a brake rotor can help to prevent squeal. From a modelling point of view, in the literature brake squeal is almost exclusively treated using models with a symmetric brake rotor, which are capable of explaining the excitation mechanism but yield no insight into the relation between rotor asymmetry and stability. In previous work, it...

Current Trends in Research on Behavioral Development in the Federal Republic of Germany

Silbereisen, Rainer K. ; Schuhler, Petra (1982)

The state and perspective of developmental psychology in the Federal Republic of Germany is analyzed with respect to (a) professional education, (b) resources for research, (c) actual fields of research, and (d) media of professional communication. Current trends of research were investigated by a combination of multi-category content analyses of national (and international) journal publication...

Maturational Timing and the Development of Problem Behavior

Silbereisen, Rainer K. ; Petersen, Anne C. ; Albrecht, Helfried T. ; Kracke, Bärbel (1989)

Previous research demonstrated a higher risk for problem behaviors among early as compared to late maturing girls. In the present study, the role of maturational timing was assessed within the framework of a developmental model for adolescent problem behavior. Data obtained twice, one year apart, on 62 girls in early adolescence (11 to 12 years of age) and 193 girls in middle adolescence (14 to...

Enhanced product functionality with life cycle units

Seliger, Günther ; Buchholz, A. ; Kross, U. (2003)

Cycle economy is not only ecologically reasonable but also a chance for new business. Selling utilization instead of selling products is advantageous once additional costs for information processing and logistics are less than costs for underutilized capacity. A competitive provider offers product functionality in quality, time and location as required by the user. Lifetime component monitoring...

Trust in high-reliability organizations

Schöbel, Markus (2009)

The present article aims to highlight the effects of trust on safety performance in high-reliability organizations (HROs) like nuclear power plants, chemical plants or hospital emergency departments. The author claims that not only beneficial but also detrimental effects have to be considered in the analysis of trust within these socio-technical systems. Potential safety outcomes of trusting be...

A mathematical model in three-dimensional piezoelectric continuum to predict non-linear responses of piezoceramic materials

Samal, M. K. ; Seshu, P. ; Wagner, Utz von ; Hagedorn, P. ; Dutta, B. K. ; Kushwaha, H. S. (2008)

It has been experimentally observed that the piezoceramic materials exhibit different types of non-linearities under different combinations of electrical and mechanical fields. When excited near resonance in the presence of weak electric fields, they exhibit typical non-linearities similar to a Duffing oscillator such as jump phenomena and the presence of superharmonics in the response spectra....

A wall shear stress measurement technique using the thermal wakes of small heated spots

Rudolph, I. ; Reyer, M. ; Nitsche, W. (2009)

A new thermo-optical method for the measurement of wall shear stresses is presented. The technique exploits that the surface temperature field and the near wall flow are closely linked by correlating the thermal wakes of small heated spots with the wall shear stress. Numerical as well as experimental results are presented and different correlation and design parameters are examined. In contrast...

Human Performance Consequences of Automated Decision Aids in States of Sleep Loss

Reichenbach, Juliane ; Onnasch, Linda ; Manzey, Dietrich (2011)

Objective: The authors investigated how human performance consequences of automated decision aids are affected by the degree of automation and the operator’s functional state. Background: As research has shown, decision aids may not only improve performance but also lead to new sorts of risks. Whereas knowledge exists about the impact of system characteristics (e.g., reliability) on human perf...

Misuse of Automation: The Impact of System Experience on Complacency and Automation Bias in Interaction with Automated Aids

Reichenbach, Juliane ; Onnasch, Linda ; Manzey, Dietrich (2010)

The study investigates how complacency and automation bias effects in interaction with automated aids are moderated by system experience. Participants performed a supervisory control task supported by an aid for fault identification and management. Groups differed with respect to how long they worked with the aid until eventually an automation failure occurred, and whether this failure was the ...

Process model based development of disassembly tools

Rebafka, Uwe ; Seliger, Günther ; Stenzel, Alexander ; Zuo, B. R. (2001)

Disassembly processes require flexible tools for loosening and handling operations. Today, disassembly processes demand a great deal of manual labour and a vast variety of tools. Partly destructive tools which generate and use new acting surfaces are able to increase the economic viability owing to their flexibility and their promotion of the reuse of components. This article describes selected...

Complacency and Bias in Human Use of Automation: An Attentional Integration

Parasuraman, Raja ; Manzey, Dietrich (2010)

Objective: Our aim was to review empirical studies of complacency and bias in human interaction with automated and decision support systems and provide an integrated theoretical model for their explanation. Background: Automation-related complacency and automation bias have typically been considered separately and independently. Methods: Studies on complacency and automation bias were analyze...