Helmut Schmidt University

Usual heat transfer fluids with suspended ultra fine particles of nanometer size are named as nanofluids, which have opened a new dimension in heat transfer processes. The recent investigations confirm the potential of nanofluids in enhancing heat transfer required for present age technology. The present investigation goes detailed into investigating the increase of thermal conductivity with temperature for nano fluids with water as base fluid and particles of Al2O3 or CuO as suspension material. A temperature oscillation technique is utilized for the measurement of thermal diffusivity and thermal conductivity is calculated from it. The results indicate an increase of enhancement characteristics with temperature, which makes the nanofluids even more attractive for applications with high energy density than usual room temperature measurements reported earlier.

The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching and task-cuing paradigms, intermittent instructions, and voluntary task selection. In the 2nd part, we discuss findings on preparatory control mechanisms in task switching and theoretical accounts of task preparation. We consider preparation processes in two-stage models, consider preparation as an all-or-none process, address the question of whether preparation is switch-specific, reflect on preparation as interaction of cue encoding and memory retrieval, and discuss the impact of verbal mediation on preparation. In the 3rd part, we turn to interference phenomena in task switching. We consider proactive interference of tasks and inhibition of recently performed tasks indicated by asymmetrical switch costs and n-2 task-repetition costs. We discuss stimulus-based interference as a result of stimulus-based response activation and stimulus-based task activation, and response-based interference because of applying bivalent rather than univalent responses, response repetition effects, and carryover of response selection and execution. In the 4th and final part, we mention possible future research fields.

This article reports or, the international Nanofluid Property Benchmark Exercise, or INPBE. in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or "nanofluids", was measured by over 30 organizations worldwide, using, a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (+/- 10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio. as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however. such differences tend to disappear when the data are normalized to the Measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

Purpose: Lean Manufacturing is widely regarded as a potential methodology to improve productivity and decrease costs in manufacturing organisations. The success of lean manufacturing demands consistent and conscious efforts from the organisation, and has to overcome several hindrances. Industry 4.0 makes a factory smart by applying advanced information and communication systems and future-oriented technologies. This paper analyses the incompletely perceived link between Industry 4.0 and lean manufacturing, and investigates whether Industry 4.0 is capable of implementing lean. Executing Industry 4.0 is a cost-intensive operation, and is met with reluctance from several manufacturers. This research also provides an important insight into manufacturers’ dilemma as to whether they can commit into Industry 4.0, considering the investment required and unperceived benefits.Design/methodology/approach: Lean manufacturing is first defined and different dimensions of lean are presented. Then Industry 4.0 is defined followed by representing its current status in Germany. The barriers for implementation of lean are analysed from the perspective of integration of resources. Literatures associated with Industry 4.0 are studied and suitable solution principles are identified to solve the abovementioned barriers of implementing lean.Findings: It is identified that researches and publications in the field of Industry 4.0 held answers to overcome the barriers of implementation of lean manufacturing. These potential solution principles prove the hypothesis that Industry 4.0 is indeed capable of implementing lean. It uncovers the fact that committing into Industry 4.0 makes a factory lean besides being smart.Originality/value: Individual researches have been done in various technologies allied with Industry 4.0, but the potential to execute lean manufacturing was not completely perceived. This paper bridges the gap between these two realms, and identifies exactly which aspects of Industry 4.0 contribute towards respective dimensions of lean manufacturing.

OBJECTIVES: The objective of this article is to report the proportion of soldiers in a Brigade Combat Team (BCT) with at least 1 clinician-confirmed deployment-acquired traumatic brain injury (TBI) and to describe the nature of sequelae associated with such injuries. PARTICIPANTS: Members of an Army unit (n = 3973) that served in Iraq were screened for history of TBI. Those reporting an injury (n = 1292) were further evaluated regarding sequelae. Of the injuries suffered, 907 were TBIs and 385 were other types of injury. The majority of TBIs sustained were mild. METHODS: Postdeployment, responses to the Warrior Administered Retrospective Casualty Assessment Tool (WARCAT) facilitated clinical interviews regarding injury history and associated somatic (ie, headache, dizziness, balance) and neuropsychiatric symptoms (ie, irritability, memory). Traumatic brain injury diagnosis was based on the American Congress of Rehabilitation Medicine mild TBI criteria, which requires an injury event followed by an alteration in consciousness. RESULTS: A total of 22.8% of soldiers in a BCT returning from Iraq had clinician-confirmed TBI. Those with TBI were significantly more likely to recall somatic and/or neuropsychiatric symptoms immediately postinjury and endorse symptoms at follow-up than were soldiers without a history of deployment-related TBI. A total of 33.4% of soldiers with TBI reported 3 or more symptoms immediately postinjury compared with 7.5% at postdeployment. For soldiers injured without TBI, rates of 3 or more symptoms postinjury and postdeployment were 2.9% and 2.3%, respectively. In those with TBI, headache and dizziness were most frequently reported postinjury, with irritability and memory problems persisting and presenting over time. CONCLUSION: Following deployment to Iraq, a clinician-confirmed TBI history was identified in 22.8% of soldiers from a BCT. Those with TBI were significantly more likely to report postinjury and postdeployment somatic and/or neuropsychiatric symptoms than those without this injury history. Overall, symptom endorsement decreased over time.

In conventional thermal spraying, the spray particles are partially or fully molten when they deposit on the substrate. Cold spraying, in contrast, uses less thermal and more kinetic energy. In this process, solid particles impact on the substrate at high velocities and form excellent coatings. Due to comparatively low temperatures and typically inert process gases, cold spraying is particularly suitable for heat and oxidation sensitive materials. In recent years, modeling and computational methods have been widely used to study this relatively new spraying process, particularly to describe impact conditions of particles, to improve nozzle design, and to provide a better understanding of the thermo-mechanical processes that lead to particle bonding and deposition. This paper summarizes the state of the art in these theoretical studies, alongside a comprehensive description of the process. The paper also discusses the prediction of coating properties in the light of modeling combined with experimental investigations.

Purpose This research introduces the combined use of partial least squares–structural equation modeling (PLS-SEM) and necessary condition analysis (NCA) that enables researchers to explore and validate hypotheses following a sufficiency logic, as well as hypotheses drawing on a necessity logic. The authors’ objective is to encourage the practice of combining PLS-SEM and NCA as complementary views of causality and data analysis. Design/methodology/approach The authors present guidelines describing how to combine PLS-SEM and NCA. These relate to the specification of the research objective and the theoretical background, the preparation and evaluation of the data set, running the analyses, the evaluation of measurements, the evaluation of the (structural) model and relationships and the interpretation of findings. In addition, the authors present an empirical illustration in the field of technology acceptance. Findings The use of PLS-SEM and NCA enables researchers to identify the must-have factors required for an outcome in accordance with the necessity logic. At the same time, this approach shows the should-have factors following the additive sufficiency logic. The combination of both logics enables researchers to support their theoretical considerations and offers new avenues to test theoretical alternatives for established models. Originality/value The authors provide insights into the logic, assessment, challenges and benefits of NCA for researchers familiar with PLS-SEM. This novel approach enables researchers to substantiate and improve their theories and helps practitioners disclose the must-have and should-have factors relevant to their decision-making.

Die Dokumentarische Methode ist eine Methodologie der qualitativen Sozialforschung, die sich seit langem in der Forschungspraxis bewährt hat. In diesem Buch wird in umfassender Weise theoretisch begrü

Why are negative emotions so central in art reception far beyond tragedy? Revisiting classical aesthetics in the light of recent psychological research, we present a novel model to explain this much discussed (apparent) paradox. We argue that negative emotions are an important resource for the arts in general, rather than a special license for exceptional art forms only. The underlying rationale is that negative emotions have been shown to be particularly powerful in securing attention, intense emotional involvement, and high memorability, and hence is precisely what artworks strive for. Two groups of processing mechanisms are identified that conjointly adopt the particular powers of negative emotions for art's purposes. The first group consists of psychological distancing mechanisms that are activated along with the cognitive schemata of art, representation, and fiction. These schemata imply personal safety and control over continuing or discontinuing exposure to artworks, thereby preventing negative emotions from becoming outright incompatible with expectations of enjoyment. This distancing sets the stage for a second group of processing components that allow art recipients to positively embrace the experiencing of negative emotions, thereby rendering art reception more intense, more interesting, more emotionally moving, more profound, and occasionally even more beautiful. These components include compositional interplays of positive and negative emotions, the effects of aesthetic virtues of using the media of (re)presentation (musical sound, words/language, color, shapes) on emotion perception, and meaning-making efforts. Moreover, our Distancing-Embracing model proposes that concomitant mixed emotions often help integrate negative emotions into altogether pleasurable trajectories.

Since the late 1960s Barney GLASER and Anselm STRAUSS, developers of the methodology of "Grounded Theory" have made several attempts to explicate, clarify and reconceptualise some of the basic tenets of their methodological approach. Diverging concepts and understandings of Grounded Theory have arisen from these attempts which have led to a split between its founders. Much of the explication and reworking of Grounded Theory surrounds the relation between data and theory and the role of previous theoretical assumptions. The book which initially established the popularity of GLASER's and STRAUSS' methodological ideas, "The Discovery of Grounded Theory", contains two conflicting understandings of the relation between data and theory—the concept of "emergence" on the one hand and the concept of "theoretical sensitivity" on the other hand. Much of the later developments of Grounded Theory can be seen as attempts to reconcile these prima facie diverging concepts. Thereby GLASER recommends to draw on a variety of "coding families" while STRAUSS proposes the use of a general theory of action to build an axis for an emerging theory. This paper first summarises the most important developments within "Grounded Theory" concerning the understanding of the relation between empirical data and theoretical statements. Thereby special emphasis will be laid on differences between GLASER's and STRAUSS' concepts and on GLASER's current critique that the concepts of "coding paradigm" and "axial coding" described by STRAUSS and Juliet CORBIN lead to the "forcing" of data. It will be argued that GLASER's critique points out some existing weaknesses of STRAUSS' concepts but vastly exaggerates the risks of the STRAUSSian approach. A main argument of this paper is that basic problems of empirically grounded theory construction can be treated much more effectively if one draws on certain results of contemporary philosophical and epistemological discussions and on widely accepted concepts developed in such debates. This especially refers to the critique of naive empiricism, to the concept of hypothetical or abductive inference, to the concept of empirical content or falsifiability of statements and to the concept of corroboration. URN: urn:nbn:de:0114-fqs0502275

This is the first comprehensive theoretical article on aesthetic emotions. Following Kant's definition, we propose that it is the first and foremost characteristic of aesthetic emotions to make a direct contribution to aesthetic evaluation/appreciation. Each aesthetic emotion is tuned to a special type of perceived aesthetic appeal and is predictive of the subjectively felt pleasure or displeasure and the liking or disliking associated with this type of appeal. Contrary to the negativity bias of classical emotion catalogues, emotion terms used for aesthetic evaluation purposes include far more positive than negative emotions. At the same time, many overall positive aesthetic emotions encompass negative or mixed emotional ingredients. Appraisals of intrinsic pleasantness, familiarity, and novelty are preeminently important for aesthetic emotions. Appraisals of goal relevance/conduciveness and coping potential are largely irrelevant from a pragmatic perspective, but in some cases highly relevant for cognitive and affective coping. Aesthetic emotions are typically sought and savored for their own sake, with subjectively felt intensity and/or emotional arousal being rewards in their own right. The expression component of aesthetic emotions includes laughter, tears, and facial and bodily movements, along with applause or booing and words of praise or blame. Aesthetic emotions entail motivational approach and avoidance tendencies, specifically, tendencies toward prolonged, repeated, or interrupted exposure and wanting to possess aesthetically pleasing objects. They are experienced across a broad range of experiential domains and not coextensive with art-elicited emotions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The emotional state of being moved, though frequently referred to in both classical rhetoric and current language use, is far from established as a well-defined psychological construct. In a series of three studies, we investigated eliciting scenarios, emotional ingredients, appraisal patterns, feeling qualities, and the affective signature of being moved and related emotional states. The great majority of the eliciting scenarios can be assigned to significant relationship and critical life events (especially death, birth, marriage, separation, and reunion). Sadness and joy turned out to be the two preeminent emotions involved in episodes of being moved. Both the sad and the joyful variants of being moved showed a coactivation of positive and negative affect and can thus be ranked among the mixed emotions. Moreover, being moved, while featuring only low-to-mid arousal levels, was experienced as an emotional state of high intensity; this applied to responses to fictional artworks no less than to own-life and other real, but media-represented, events. The most distinctive findings regarding cognitive appraisal dimensions were very low ratings for causation of the event by oneself and for having the power to change its outcome, along with very high ratings for appraisals of compatibility with social norms and self-ideals. Putting together the characteristics identified and discussed throughout the three studies, the paper ends with a sketch of a psychological construct of being moved.

Climate-induced migration is one of the most hotly debated topics in the current discourse on global warming and its consequences. There is a burgeoning field in economics and other social sciences linking climatic factors or climate-related natural disasters to migration. Existent empirical studies use different measures to quantify migration flows and climatic factors and apply a variety of methodologies to disparate data sets and samples of countries. Our review article aims to provide a unifying perspective over this complex field by structuring the literature and summarizing the empirical findings.

Coping with evolution in automated production systems implies a cross-disciplinary challenge along the system's life-cycle for variant-rich systems of high complexity. The authors from computer science and automation provide an interdisciplinary survey on challenges and state of the art in evolution of automated production systems. Selected challenges are illustrated on the case of a simple pick and place unit. In the first part of the paper, we discuss the development process of automated production systems as well as the different type of evolutions during the system's life-cycle on the case of a pick and place unit. In the second part, we survey the challenges associated with evolution in the different development phases and a couple of cross-cutting areas and review existing approaches addressing the challenges. We close with summarizing future research directions to address the challenges of evolution in automated production systems.

This paper argues that it is useful to regard `reputational risk' as a pervasive logic of organizing and organizational attention. First, we suggest that the risk management agenda has expanded from its roots in technical analysis to become a cornerstone of good governance and responsible actorhood. We illustrate this claim in the context of English universities. Second, we suggest that this expansion in the reach and significance of risk management has increased organizational orientations to reputational risk and to more defensively and legalistically framed forms of asset management. Specifically, organizations are responding to the growth of external bodies which evaluate and rank, and thereby generate reputational risk. In the context of universities, we argue that this leads both to specific transformations in organizational practices in response to ranking systems, and also to an increased generalized concern with reputational risk, which is a symptom of late modern insecurity.

Despite the ongoing "war" between methodological camps this paper will argue for an integration of qualitative and quantitative methods in the sociological research process. For this purpose a short overview about important methodological discussions addressing basic questions of mixed (qualitative and quantitative) method designs will be given focusing on the term "triangulation" which is seen by many authors as a central concept for method integration. However, this notion carries systematic ambiguities, at least when transferred to the integration of qualitative and quantitative methods—triangulation does not represent a single integrated methodological concept but a metaphor with a broad semantic field. Three different understandings of the triangulation metaphor will be discussed: Triangulation as mutual validation, triangulation as the integration of different perspectives on the investigated phenomenon and triangulation in its original trigonometrical meaning. These understandings of triangulation will be contrasted with examples from sociological life-course research projects which combined qualitative and quantitative panels in order to answer certain research questions. The examples clearly demonstrate that each of the three understandings may have a value by showing different possibilities for relating qualitative and quantitative results in one research project to each other. However, none of these three concepts may serve as a general methodological model for the integration of qualitative and quantitative methods. In the final section of the paper it will be argued that the most crucial problem of the methodological discussions surrounding mixed-method (qualitative and quantitative) designs is that epistemological and methodological concepts are not sufficiently linked to theoretical considerations about the nature of the investigated social structures and social processes. In its concluding section the paper will briefly outline some ways that the already-discussed examples from sociological life course research as well as the discussions about triangulation could be integrated into a more general theoretical framework. The focus of these considerations will lie on the distinction between the micro- and macro-level of sociological description and on current discussions about individualisation processes in modernising societies. Thereby it will be shown that an understanding of triangulation in its original trigonometrical sense (although it cannot be considered as a methodological model suitable for all aspects of method integration) may be helpful in gaining a deeper insight into theoretical aspects of method integration in sociology. URN: urn:nbn:de:0114-fqs010159

Nanofluids have shown remarkable attraction in heat transfer community due to its reported enhanced thermal properties. One factor which can restrict nanofluids in heat transfer application is the increased viscosity value (compared to classical predictions). Particle aggregation occurring was the major reason for this observation. Even though majority of the aqueous nanofluids prepared in literature were stabilized electrostatically by adjusting the pH, studies on the effect of the electrical double layer thus created and its influence on viscosity increase has not been investigated for these nanofluids so far. Thus, in the present paper, rheological properties of alumina-water nanofluids, which are electrostatically stabilized, are measured and the increase in suspension viscosity due to presence of this electrical double layer causing additional electroviscous effects is brought out. Based on dynamic light scattering studies, particle agglomeration and its subsequent effect in increasing the viscosity of alumina-ethylene glycol nanofluid, where electroviscous effects are absent, are also considered. It is noted that the understanding of electroviscous effect is equally important as understanding the particle agglomeration effect and understanding both the effects is central to revealing the physics of nanofluid rheology. Further, hydrodynamic experiments are made, which show that nanofluids behaves almost like a homogeneous fluids under flow conditions, and by knowing their properties, such as viscosity and density, pressure drop can be predicted.

Over the last decade's magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as well as their extraordinary high gravimetric and volumetric storage densities. This review work provides a broad overview of the most appealing systems and of their hydrogenation/dehydrogenation properties. Special emphasis is placed on reviewing the efforts made by the scientific community in improving the material's thermodynamic and kinetic properties while maintaining a high hydrogen storage capacity.

Musical emotions, such as happiness and sadness, have been investigated using instrumental music devoid of linguistic content. However, pop and rock, the most common musical genres, utilize lyrics for conveying emotions. Using participants' self-selected musical excerpts, we studied their behavior and brain responses to elucidate how lyrics interact with musical emotion processing, as reflected by emotion recognition and activation of limbic areas involved in affective experience. We extracted samples from subjects' selections of sad and happy pieces and sorted them according to the presence of lyrics. Acoustic feature analysis showed that music with lyrics differed from music without lyrics in spectral centroid, a feature related to perceptual brightness, whereas sad music with lyrics did not diverge from happy music without lyrics, indicating the role of other factors in emotion classification. Behavioral ratings revealed that happy music without lyrics induced stronger positive emotions than happy music with lyrics. We also acquired functional magnetic resonance imaging data while subjects performed affective tasks regarding the music. First, using ecological and acoustically variable stimuli, we broadened previous findings about the brain processing of musical emotions and of songs versus instrumental music. Additionally, contrasts between sad music with versus without lyrics recruited the parahippocampal gyrus, the amygdala, the claustrum, the putamen, the precentral gyrus, the medial and inferior frontal gyri (including Broca's area), and the auditory cortex, while the reverse contrast produced no activations. Happy music without lyrics activated structures of the limbic system and the right pars opercularis of the inferior frontal gyrus, whereas auditory regions alone responded to happy music with lyrics. These findings point to the role of acoustic cues for the experience of happiness in music and to the importance of lyrics for sad musical emotions.

A general algorithm for the decomposition of differences between two values of an aggregate demographic measure in respect to age and other dimensions is proposed. It assumes that the aggregate measure is computed from similar matrices of discrete demo