Hypotrochoidal profile contours have been produced in industrial applications in recent years using two-spindle processes, and they are considered effective high-quality solutions for form-fit shaft and hub connections. This study mainly concerns analytical approaches to determine the stresses and deformations in hypotrochoidal profile shafts due to pure bending loads. The formulation was developed according to bending principles using the mathematical theory of elasticity and conformal mappings. The loading was further used to investigate the rotating bending behaviour. The stress factors for the classical calculation of maximum bending stresses were also determined for all those profiles presented and compiled in the German standard DIN3689-1 for practical applications. The results were also compared with the corresponding numerical and experimental results, and very good agreement was observed. Additionally, based on previous work, the stress factor was determined for the case of torsional loading to calculate the maximum torsional stresses in the standardised profiles, and the results are listed in a table. This study contributes to the further refinement of the current DIN3689 standard.
This paper presents an analytical method for determining the bending stresses and deformations in prismatic, noncircular profile shafts with trochoidal cross sections. The so-called higher trochoids can be used as form-fit shaft-hub connections. Hybrid (mixed) higher trochoids (M-profiles) were developed for the special application as a profile contour for the form-fit shaft and hub connections in an earlier work by the author. M-profiles combine the advantages of the two standardised polygonal and spline contours, which are used as shaft-hub connections for the transmission of high torques. In this study, the geometric and mechanical properties of the higher hybrid trochoids were investigated using complex functions to simplify the calculations. The pure bending stress and shaft deflection were determined for M-profiles using bending theory based on the theory of mathematical elasticity. The loading cases consisted of static and rotating bends. Analytical, numerical, and experimental results agreed well. The calculation formulas developed in this work enable reliable and low-cost dimensioning with regard to the stresses and elastic deformations of profile shafts subjected to bending loads.
Duplex steels are used for applications that require high strength and ductility combined with good corrosion resistance. An economical welding technology to handle these steels is achieved by combining the MIG and TIG arc processes. The aim is to improve welding speed and quality by utilizing a TIG-MIG hybrid welding process to join 1.4462 duplex steel with a thickness of 2 mm. The interaction between the two arcs, caused by the blowing effect, is an enormous challenge that can be counteracted with a defined torch position and current modulation. For this purpose, a variation of the MIG (pulsed and AC pulsed arc) and TIG process (AC and pulsed DC) took place. The influence of electrical parameters on process stability and material transfer was investigated. For analysis, an evaluation of high-speed recordings (5000 frames per second) and synchronized measured current/voltage curves (200 kHz) is carried out. Based on a number of selected specimens, a welding procedure test according to ISO 15614-1 is performed to determine the welding seam quality. The test includes the characterization by tensile and hardness testing and macroscopic and microscopic examination. Additionally, the specimens are examined according to ISO 5817.
The atomizing gas dynamics and the applied process energy have a significant influence on the produced particles. The melting process of the two wires can be influenced by current modulation. As for arc welding processes, more and more electronic and software-controlled machines are being used for arc spraying and will have replaced conventional power sources in the future. Due to the highly dynamic, fast regulating computing technology in the latest energy source, technology arcs can be operated with different current forms and types. The modern machines allow process-stable, reproducible variation of the particles and heat input into the substrate. Constant and pulsed current can be used as current forms. Usable current types are direct current (DC) and alternating current (AC). The electrical parameters must be analyzed to evaluate the process behavior. The consumable used is a wire-shaped iron-based alloy with a diameter of 1.6 mm. Relevant process parameters such as basic current Iground, pulse current Ipulse, pulse duration tpulse, impulse frequency fpulse, and alternating current frequency, fAC, are varied and recorded using appropriate measurement technology. The aim is to change the process performance and thereby the particle formation in a broad band. High-speed images are used to observe the arc and the deposition process. In addition, particle sizes are determined.
The removal of bacterial infections within the root canal system is still a challenge. Therefore, the cleansing effect of established and new irrigation-protocols (IP) containing silver diamine fluoride (SDF) 3.8% on the whole root canal system was analyzed using quantitative PCR (qPCR) and 4′,6-diamidino-phenylindole-(DAPI)-staining. Extracted human premolars were instrumented up to F2 (ProTaper Gold) under NaCl 0.9% irrigation and incubated with Enterococcus faecalis for 42 days. Subsequently, different ultrasonically agitated IP were applied to the roots: control (no irrigation), 1. NaOCl 3%, EDTA 20%, CHX 2%, 2. NaOCl 3%, EDTA 20%, 3. NaOCl 3%, EDTA 20%, SDF 3.8%, 4. SDF 3.8%, and 5. NaCl 0.9%. One half of the root was investigated fluorescent-microscopically with DAPI. The other half was grinded in a cryogenic mill and the bacterial DNA was quantified with qPCR. The qPCR results showed a statistically significant reduction of bacteria after the application of IP 1, 2, and 3 compared to the control group. While IP 4 lead to a bacterial reduction which was not significant, IP 5 showed no reduction. These data corresponded with DAPI staining. With qPCR a new molecular-biological method for the investigation of the complete root canal system was implemented. The novel IP 3 had an equally good cleansing effect as the already established IP.
This article presents a cost-effective ultraviolet-ozone cleaner (UV/O3 Cleaner) for surface pre-treatment of substrates in the field of semiconductor technology. The cleaner consists of two chambers, the upper one contains the electronics, including the time counter. The lower chamber contains the two UV sterilisation lamps and a UV reflector of anodized aluminium, which confines the area of high Ozone concentration in the area of interest. The device is successfully used for surface cleaning and modification of different materials. To this end, the two important wavelengths 253.7 nm (excitation of organic residues) and 184.9 nm (production of ozone from the atmospheric environment as a strong oxidant) were first detected. The effectiveness of UV/O3 cleaning is demonstrated by improving the properties of indium tin oxide (ITO) for OLED fabrication. The contact angle of water to ITO could be reduced from 90° to 3° and for diiodomethane, it was reduced from 55° to 31° within the 10 min of irradiation. This greatly improved wettability for polar and non-polar liquids can increase the flexibility in further process control. In addition, an improvement in wettability is characterized by measuring the contact angles for titanium dioxide (TiO2) and polydimethylsiloxane (PDMS). The contact angle of water to TiO2 decreased from 70° to 10°, and that of diiodomethane to TiO2 from 54° to 31°. The wettability of PDMS was also greatly increased. Here, the contact angle of water was reduced from 109° to 24° and the contact angle to diiodomethane from 89° to 49°.
Article Highlights
We report a cost-effective dry-cleaning device for surface cleaning and modification based on ultraviolet-ozone irradiation.
Contact angle measurements show an increase of wettability for different materials due to surface modification.
The UVO3 pre-treatment improves layer formation and optoelectrical properties of OLEDs.
Introduction: In the spring of 2020, coronavirus disease 2019 posed a substantial challenge for countries and their healthcare systems. In Germany, over 70% of all cancer patients are treated in an outpatient setting, so gynecologic oncology practices are the guarantors of optimal patient care. We developed a survey to evaluate the management of gynecologic oncology patients.
Methods: The survey consisted of 38 questions and was sent to the members of the Berufsverband Niedergelassener Gynäkologischer Onkologen in Deutschland e.V. (BNGO), a professional association of gynecologic oncologists in the outpatient sector in Germany.
Results: The survey was completed by 54 out of 133 (41%) gynecologic oncologists from 14 out of 15 (93%) federal states where the BNGO is represented. Facing the pandemic, popular measures were mask requirements (100%), restriction of access to practices (94%), increased number of disinfectant dispensers (85%), installment of panes of acrylic glass (76%), or spatial alterations (67%). For most patients the pandemic had no influence on prioritization of therapies (82%) or prescribed systemic treatments (87%). Despite an increase in perceived psychological burden among the staff (72%), 85% (45/54) of the practices were not offered any additional psychological support.
Discussion and Conclusion: As most cancer patients in Germany are treated in an outpatient setting, a suitable reaction of oncology centers to the new circumstances was crucial to secure optimal treatment and patient care. Nevertheless, the low prioritization of mental health or distress of healthcare workers poses a serious threat to the maintenance of optimal medical care in further waves of the pandemic.
This paper deals with systematic approaches for the analysis of stability properties and controller design for nonlinear dynamical systems. Numerical methods based on sum-of-squares decomposition or algebraic methods based on quantifier elimination are used. Starting from Lyapunov’s direct method, these methods can be used to derive conditions for the automatic verification of Lyapunov functions as well as for the structural determination of control laws. This contribution describes methods for the automatic verification of (control) Lyapunov functions as well as for the constructive determination of control laws.
Sustainable Integration of Digitalisation in Nursing Education - An International Scoping Review
(2024)
Model predictive control (MPC) is a promising approach to the lateral and longitudinal control of autonomous vehicles. However, the parameterization of the MPC with respect to high-level requirements such as passenger comfort, as well as lateral and longitudinal tracking, is challenging. Numerous tuning parameters and conflicting requirements need to be considered. In this paper, we formulate the MPC tuning task as a multi-objective optimization problem. Its solution is demanding for two reasons: First, MPC-parameterizations are evaluated in a computationally expensive simulation environment. As a result, the optimization algorithm needs to be as sample-efficient as possible. Second, for some poor parameterizations, the simulation cannot be completed; therefore, useful objective function values are not available (for instance, learning with crash constraints). In this work, we compare the sample efficiency of multi-objective particle swarm optimization (MOPSO), a genetic algorithm (NSGA-II), and multiple versions of Bayesian optimization (BO). We extend BO by introducing an adaptive batch size to limit the computational overhead. In addition, we devise a method to deal with crash constraints. The results show that BO works best for a small budget, NSGA-II is best for medium budgets, and none of the evaluated optimizers are superior to random search for large budgets. Both proposed BO extensions are, therefore, shown to be beneficial.
Alternative Leistungskennzahlen (APM) in der Finanzberichterstattung österreichischer Emittenten
(2022)
Routing games over time are widely studied due to various applications, e.g., transportation, road and air traffic control, logistic in production systems, communication networks like the internet, and financial flows. In this article, we present a new competitive packet routing game with edge priorities motivated by traffic and transportation. In this model a set of selfishly acting players travels through the network over time. If the number of players who want to enter an edge at the same time exceeds the inflow capacity of this edge, then edge priorities with respect to the preceding edge are used to resolve these conflicts, which is similar to right-of-way rules in traffic. We analyze the efficiency of pure Nash equilibria, present an efficient algorithm for computing equilibria in symmetric games, and show that it is NP-hard to decide whether a Nash equilibrium exists in an asymmetric game. Furthermore, we address the problem of constructing optimal priorities.
Hintergrund: Wenn professionelle Unterstützung fehlt, erkennen pflegende Angehörige selten eigene Überlastungssituationen und nehmen Unterstützungsleistungen bei Pflegebedürftigkeit daher unzureichend in Anspruch.
Ziel: Die Studie untersucht die Versorgung von Menschen mit Pflegebedarf, den Kenntnisstand zu Entlastungsleistungen sowie Belastungsfaktoren bei der Übernahme pflegerischer Leistungen aus Sicht informell Pflegender und Nicht-Pflegender.
Methode: Es wurde eine Querschnittstudie mittels standardisierter Computer Assisted Telephone Interviews (CATI) mit Personen ab dem 18. Lebensjahr in Sachsen durchgeführt. Deskriptive und bivariate Statistiken wurden berechnet.
Ergebnisse: Die Versorgung durch einen ambulanten Pflegedienst oder durch pflegende Angehörige bewerteten von 601 Teilnehmenden 259 informell Pflegende gegenüber 342 Nicht-Pflegenden signifikant besser ( N = 601). Weiterhin hatten die informell Pflegenden und die Nicht-Pflegenden unterschiedliche Kenntnisse über den nächstgelegenen Ort der Pflegeberatung und über Ausgleichzahlungen der Rentenversicherung. Schlussfolgerungen: In einzelnen Bereichen der abgefragten Beratungsleistungen und Entlastungsmöglichkeiten hat sich das Antwortverhalten von pflegenden Angehörigen gegenüber den anderen Teilnehmenden signifikant unterschieden. Es kann von einem geringen Informationsvorsprung der pflegenden Angehörigen bei der Inanspruchnahme von Unterstützungsleistungen ausgegangen werden.
The demand for thorough disinfection within ambulances is essential, given the in-vehicle medical procedures and the potential high risk of infections due to patients' open wounds. One solution that can address this hygiene challenge involves the application of reactive products generated from atmospheric (air) oxygen and water vapor, activated through the use of cold plasma. Cold plasma's charged particles perforate the cell membranes of microorganisms. This process does not work in human cells, as proteins in the form of enzymes within the body break down the cold plasma and protect the cells. The study was done on an ambulance that was contaminated in eight places. Samples were taken from each site, and two surfaces measuring approximately 8 × 8 cm were carefully sealed and marked. These surfaces were deliberately contaminated by applying an Enterococcus faecium suspension of 8.5 × 107 CFU/mL using a sterile cotton swab. It was followed by the disinfection procedure, that was initiated with the PLASMOCAR device. It was positioned on the front workspace and operated for a duration of 30 min, utilizing the vehicle's onboard voltage. Throughout the operation, all doors and windows were closed and the vehicle's air conditioning system remained active. After the completion of the disinfection process, samples were collected from the surfaces for bacterial counts. A reduction of 3.73 log levels in initial bacteria was accomplished within the rescue vehicle for Enterococcus faecium, equivalent to a 10–fourfold reduction in bacteria, eliminating up to 99.99% of the initial microorganisms. This success makes the process well-suited and convenient as an ongoing "background" procedure to enhance the established disinfection procedures. The established disinfection procedures outlined in the hygiene plan must be promptly implemented whenever mechanical surface cleaning is required. The use of PLASMOCAR offers an extra layer of protection and security, significantly decreasing the risk of microorganism transmission through cross-contamination and aerosols. This is a significant benefit for the well-being of both staff and patients.
A novel approach to consider triaxial tensile stresses within the framework of a failure criterion
(2022)
For use in micromechanical simulations of continuous fiber reinforced polymers, a more general form of the paraboloid failure criterion by Stassi‐D'Alia for matrix failure was developed with explicit consideration of the hydrostatic tension strength. Regarding polymers, limits for hydrostatic tensile strength based on isotropic linear elasticity could be derived. The comparison of the newly developed extended paraboloid criterion with experimental data for yielding as well as for material separation (fracture) shows good agreement.
Auf digitalen Märkten besteht, wer die zugrundeliegenden digitalen, unternehmensbezogenen oder akteursübergreifenden institutionellen Arrangements versteht und aktiv gestaltet. Dazu werden ausgereifte, von Forschung und Praxis diskutierte und gemeinsam weiter entwickelte Methoden zum Design digitaler Plattformen, Geschäftsmodelle und Service-Ökosysteme benötigt. Einen gemeinschaftlichen Aufschlag hierzu macht der folgende Artikel. Er entstand aus einem offenen Aufruf in der Wirtschaftsinformatik-Community – über Mailing-Listen und soziale Medien. Im Ergebnis führen sieben Forschergruppen (oder einzelne Forscher und Forscherinnen) ihre aktuellen Erkenntnisse zu diesem Thema zusammen.
Recent surveys and political research have shown that the acceptance of the political programmes of populist parties, such as the “Alternative für Deutschland (AfD)”, is relatively high amongst the population of the three eastern German federal states, especially in Saxony, where the AfD won nine of the 13 rural districts during the local elections in May 2019. Thus, it seems relevant to take a closer look at the persuasive discourse of a so-called populist party. In its public discourse, the AfD responds to the fears and concerns of those people who tend to use social media platforms to gain information when making political decisions. The aim of the article is to show which verbal and visual resources characterize the persuasive discourse of the AFD Saxony on their Facebook account. For this purpose, we propose a qualitative, multimodal analysis of selected entries which the party uploaded on its Facebook account between November 2018 and March 2019.
Sodium iron hexacyanoferrate (NaFeHCF) films were electrodeposited on Au/Cr/Si for the study of growth behavior and physical properties. The NaFeHCF films were studied by different analytical methods to prove the chemical composition, morphology and crystal structure. The grains of the film grow with a cubic structure with an average lattice parameter of 10.10 Å and the preferential growth direction along the [111] direction of the cubic cell. The films show a repeatable bipolar resistive switching behavior accompanied by high current changes (up to a factor of ~105). The different resistive states in the materials are dominated by ohmic conduction.
Traffic calming is introduced to minimise the negative results of motor vehicle use, for example, low safety level or quality of life, high noise and pollution. It can be implemented through the introduction of road infrastructure reducing the velocity and the traffic volume. In this paper, we studied how traffic-calming influences the traffic assignment. For the research, a traffic-calming measure of speed cushions on the Stachiewicza street in Krakow was taken. A method of extracting trajectories from aerial footage was shown, and it was used to build a model. For a given example, through driving characteristics research and microscopic modelling, volume–delay BPR functions were estimated—for a street with and without traffic calming. Later, a toy network of two roads of the same length, connecting the same origin and destination, was simulated using an equilibrium traffic assignment method. Simulations were conducted both with the use of PTV Vissim and Visum software and through individual calculations. According to the results of this paper, there was a difference in traffic volume according to the equilibrium traffic assignment in the aforementioned toy network as a function of total network traffic volume.
En 1985 inició el Ministerio de Educación en Venezuela el Modelo de Atención Integral al Niño Sordo, un cambio de la práctica oralista a un modelo bilingüe en las escuelas de sordos. Eso implicaba eliminar la enseñanza del español hablado como objetivo principal e introducir la Lengua de Señas Venezolana (LSV) a las escuelas. Se desencadenó así un intenso período de cambios que marcó indeleblemente a la comunidad sorda. Aquí se aborda el Modelo desde la perspectiva de la planeación lingüística, describiendo sus objetivos y sus efectos sobre la adquisición, la estructura (el corpus) y el estatus de la LSV: La LSV y el español señado fueron reubicados en la diglosia existente hasta entonces; surgió una variante académica de la LSV y aumentó el número de usuarios de la LSV. El estudio se basó en el análisis cualitativo de entrevistas realizadas a cinco testigos de aquel proceso.
Conceptual Approach to an AI-Based Adaptive Study Support System for Individualized Higher Education
(2023)
In the context of the digital transformation, the targeted implementation of AI-based or AI-supported technologies in "teaching & learning" as well as "administration & service" holds considerable potential for organizational change and quality enhancement for higher education institutions. The use of AI in higher education teaching and services lags behind the level in research. Therefore, holistic solutions must be planned and implemented in unity of teaching and research for the AI-based support of the stakeholders’ inclusive administration, the further development or the establishment of new digital study programs and offers as well as the prospective qualification of university staff in the field of AI. The solutions must be analyzed, systematized, and structured to generate a conceptual approach via an integrated architecture with adaptive services.
This paper is an evolution of the concept presented at the Learning Ideas Conference 2022 and includes, in addition to explanations of the current state of the arts, the presentation of a systems-oriented approach for AI in higher education as well as the conception of the student lifecycle management at the author’s university. The paper ends with the presentation of a concept regarding a decision support system for individualized studying.
Analgesic drug use of recreational and competitive badminton players: Starting points for prevention
(2021)
Objectives: Evidence-based clinical guidelines play an important role in healthcare and can be a valuable source for quality indicators (QIs). However, the link between guidelines and QI is often neglected and methodological standards for the development of guideline-based QI are still lacking. The aim of this qualitative study was to get insights into experiences of international authors with developing and implementing guideline-based QI.
Setting: We conducted semistructured interviews via phone or skype (September 2017–February 2018) with guideline authors developing guideline-based QI.
Participants: 15 interview participants from eight organisations in six European and North American countries.
Methods: Organisations were selected using purposive sampling with a maximum variation of healthcare settings. From each organisation a clinician and a methodologist were asked to participate. An interview guide was developed based on the QI development steps according to the ‘Reporting standards for guideline-based performance measures’ by the Guidelines International Network. Interviews were analysed using qualitative content analysis with deductive and inductive categories.
Results: Interviewees deemed a programmatic approach, involvement of representative stakeholders with clinical and methodological knowledge and the connection to existing quality improvement strategies important factors for developing QI parallel to or after guideline development. Methodological training of the developing team and a shared understanding of the QI purpose were further seen conducive. Patient participation and direct patient relevance were inconsistently considered important, whereas a strong evidence base was seen essential. To assess measurement characteristics interviewees favoured piloting, but often missed implementation. Lack of measurability is still experienced a serious limitation, especially for qualitative aspects and individualised care.
Conclusion: Our results suggest that developing guideline-based QI can succeed either parallel to or following the guideline process with careful planning and instruction. Strategic partnerships seem key for implementation. Patient participation and relevance, measurement of qualitative aspects and piloting are areas for further development.
Trial registration number: German Clinical Trials Registry (DRKS00013006).
This article aims to identify the status quo of sustainability covenants firstly, secondly analyze their possibilities in enhancing sustainability performance and thirdly present further research directions. Covenants are additional contractual agreements mainly used in financial contracts, e.g. loans. They often focus on financial performance indicators, e.g., equity and net debt ratio, which the borrower must fulfil. However, the purpose of this article is to present a new approach to non-financial covenants, so-called sustainability covenants. Therefore, also nowadays ecological and social challenges are addressed. Banks have a huge impact on sustainable development by introducing more non-financial indicators in evaluating the creditability of borrowers. As a key hypothesis, this article argues that the approach of integrating ecological and social objectives through non-financial covenants is underrepresented in economic and business practice. Therefore, this article wants to examine how those objectives can be integrated into the financial concept of covenants and rely on research towards an integrative sustainability approach. In addition, a systematic literature review was conducted from October 2022 to July 2023 to analyze the status quo and derive future research directions. The review was based on two databases – Google Scholar and Scopus. As one key result, it was revealed that there is scarce existing literature on sustainability covenants, which refers to them as a policy measure. Only a few publications analyze their usage in financial contracts. However, this study implies the necessity for further research on sustainability covenants, emphasizing that they are powerful indicators to enhance the sustainability performance of the borrower.
In this work, a new method for selecting suitable materials is presented. This method has a high potential for a variety of engineering applications, such as the design of sound-absorbing and vibration-loaded structures, where a large number of different requirements have to be met. The method is based on the derivation of functional dependencies of selected material parameters. These dependencies can be used in parameter studies to consider parameter combinations that lie in the range of real existing and targeted material groups. This allows the parameter space to be reduced, the calculation to be accelerated, and suitable materials to be (pre-)selected for the respective application, which contributes to a more target-oriented design. The method is applied to the example of a plate resonator. For this purpose, a semi-analytical model is implemented to calculate the transmission loss as well as the reflected and dissipated sound power of plate silencers, taking into account the influence of flow velocity and fluid temperature on the performance of plate silencers.
Analysis of a Film Forming Process through Coupled Image Correlation and Infrared Thermography
(2022)
The aim of the present investigation was to determine the dependence of the material and process parameters of the bending process of thermoplastic films. In this context, parameter combinations leading to high resulting forming ratios were identified. To measure the relevant parameters within the hot bending process, a coupled evaluation of infrared thermography (IRT) and deformation measurement using digital image correlation (DIC) was performed. The coupled measurement enables the identification of the actual mechanically stressed bending area of the film as a result of the bending process. This allows for the specification of the local forming temperatures required for the desired forming ratios. Furthermore, the mechanical and thermal strain along the defined measuring sections and their deviation in individual tests as well as the effect of thermal strain on process control on a larger scale were determined. Based on the results, a process window was defined for the film materials investigated, which will serve as a starting point for future efforts to develop a continuous manufacturing process.
The purpose of this article is to revise the literature on how theories have been utilized in investigating third-parties (for example, Non-Governmental Organizations, certifying organizations, among others) in Sustainable Supply Chain Management. Based on that, we derive future research directions. For revising the literature in a structured manner, the articles use the systematic literature review as the method of choice. Only half of the identified articles utilize theories for investigating third-parties in Sustainable Supply Chain Management. In addition, major theories are overweighed. This predomination leads to influencing the conceptualization of third-parties in Sustainable Supply Chain Management. Future research opportunities exist in broadening the utilization of theories and methods applied in the field, investing in under-explored aspects and broadening the scope of testing and building frameworks. Based on the synthesizing, propositions supplement future research directions. The novelty of this article lies in its investigation of how theories have been used in investigating and conceptualizing third-parties in Sustainable Supply Chain Management. By that, it contributes with a state-of-the-art view on the important topic of sustainability and how third-parties could solve sustainability challenges. With that, the article is a first attempt and step for extending the academic literature and practice with rethinking classic ways of managing sustainability and utilize out of the box ideas.
Hybrid manufacturing of titanium Ti-6Al-4V combining laser metal deposition and cryogenic milling
(2020)
Hybrid manufacturing, which, e.g., combines additive manufacturing with conventional machining processes, can be a way of overcoming limitations currently encountered in additive manufacturing. Cryogenic milling might be a viable option for hard-to-cut materials, as it leaves a contamination-free surface and can increase surface quality and tool life compared to conventional cooling concepts. In this study, the influence of cryogenic milling with carbon dioxide on titanium Ti-6Al-4V specimens manufactured with laser metal deposition (LMD) was investigated regarding tool wear and surface integrity in comparison to dry machining and machining with cooling lubricants. Moreover, additional layers of material were deposited on top of conventionally and cryogenically machined surfaces by means of LMD. The interface zone was then examined for defects. The milling process was closely monitored by means of thermal and high-speed imaging. Optical and tactile surface analysis provided evidence that lower roughness values and improved surface qualities could be obtained with cryogenic machining in comparison to dry machining. Moreover, significantly less tool wear was observed when a cryogenic cooling medium was applied. Although the utilization of conventional cooling lubricants resulted in satisfying surface qualities, substantial residual contamination on the milled surface was detected by means of fluorescence analysis. These contaminants are suspected to cause defects when the next layer of material is deposited. This is supported by the fact that pores were found in the weld bead applied on top of the milled specimens by means of LMD. Conversely, cryogenic machining resulted in very clean surfaces due to the residue-free evaporation of the coolant. Hence, a good metallurgical bonding between the weld bead and the milled substrate could be achieved. The results indicate the great potential of cryogenic milling in hybrid manufacturing, especially in terms of intermediate machining, as it provides residue-free surfaces for subsequent material deposition without an additional cleaning step and can significantly prolongate tool life.
Die Autoren bringen langjährige Erfahrung in verschiedenen Industriebranchen und der akademischen Ausbildung im Lean- und Project and Process Management mit sich. Im Rahmen der beruflichen Tätigkeit und der akademischen Arbeit hat sich immer wieder die Frage gestellt, wie die Philosophie des Lean Management mit den Aufgaben des Projekt Management Office interagieren können. Viele Ansätze des Lean Management, vor allem organisatorische Methoden zeigen eine breite Anwendungsmöglichkeit und sollten somit auch dem Projekt Management Office (PMO) hilfreich sein. Vor einiger Zeit hat sich schon der Begriff des Lean Office [YDF01] etabliert, der aber sowohl in der Büroorganisation als auch der Dokumentenpflege Ansatz findet. Im Rahmen des PMO soll dieser Lean Office auf die bereitzustellenden Prozesse und deren Integration ins Enterprise Ressource Planning Anwendung finden. Je schlanker und effizienter die Projekt- und Programmprozesse einer Organisation aufgestellt werden, desto leichter können diese abgebildet und in die Enterprise Ressource Planning (ERP)-Datenlandschaft übertragen werden. Somit wird ein solider Grundstein über den gesamten Produktprozess gelegt - von der Entwicklung, über die Herstellung bis hin zur schlussendlichen Verwertung schlank, effizient, automatisiert und digitalisiert abgebildet zu sein.
Dissipation energy based parameter identification of anisotropic linear viscoelastic composites
(2020)
The current work presents a relaxation analysis based procedure to identify effective material parameters of the multiaxial generalized Maxwell model (GMM) by a numerical homogenization of the microscopic dissipation energy density for anisotropic linear viscoelastic composites. The employed GMM enables the derivation of a thermodynamically consistent constitutive law and a function of the dissipation energy density for direction‐dependent viscoelastic materials. The identity of this energy function to the microstructure's homogenized dissipation energy density is utilized for the identification of effective relaxation times. Furthermore, the identified relaxation times enable a simple determination of the remaining stiffness parameters. Finally, the presented procedure is demonstrated and evaluated for a randomly endless fibre‐reinforced plastic with a polymer matrix exhibiting a significant viscoelastic behaviour.
Die Arbeitswissenschaft untersucht die Bedingungen und Auswirkungen menschlicher Arbeit, um daraus Beurteilungs- und Gestaltungsregeln zu gewinnen. Mit dem Wandel des Arbeitslebens verändern sich auch die Rahmenbedingungen der Arbeit selbst dynamisch. Auslöser solcher Prozesse sind Veränderungen von Arbeits- und Lebensstil, der Mensch-Technik-Interaktion, der Arbeitszeit sowie den damit verbundenen Anforderungen an Flexibilität, Mobilität, Entscheidungsfähigkeit und Selbstorganisation. Als Folge dieser Entwicklung lässt sich ein Anstieg der Komplexität arbeitsbezogener Anforderungen feststellen. Eine korrekte Einordnung entsprechender Arbeitsbelastungen bedarf einer ganzheitlichen Betrachtung der Wirkung gegenseitiger Beziehungen. Damit schließen sich eine Vielzahl klassischer Verfahren der Arbeitsanalyse, die die einzelnen Sachverhalte situativ und losgelöst voneinander betrachten, aus.
Da eine Beurteilung komplexer Anforderungssituationen für den einzelnen Arbeitsanalytiker nur bedingt beherrschbar sein kann, setzt sich der Beitrag theoretisch und empirisch mit der Frage auseinander, ob durch den Einsatz von Wearables eine analytische Begleitung und Assistenz menschlicher Arbeit möglich ist. Es wird der Frage nachgegangen, ob mittels Wearables objektive und belastbare Aussagen zur Wirkung dynamischer Bündel unterschiedlicher Belastungen möglich sind, um anerkannte Verfahren der Arbeitssystemanalyse zu ergänzen, zu substituieren bzw. weiterzuentwickeln.
Während eines Betriebsrundgangs mit dem Werkleiter zur Beurteilung der Ergonomie an Arbeitsplätzen verweilte dieser on einer lärmintensiven Anlage, zog sein Smartphone aus der Jackettasche und hielt es in Richtung der Maschine, um deren Schallpegel zu messen. Augenblicke später recherchierte er über die Suchfunktion des Gerätes nach zulässigen Grenzwerten. Am Ende des Rundgangs entspann sich eine Diskussion über die Aussagefähigkeit und Zuverlässigkeit Smartphone-gestützter Messungen von Arbeitsumweltfaktoren. Eine Studie am Institut für Produktionstechnik der Westsächsischen Hochschule Zwickau sollte klaren, ob es überhaupt noch des Einsatzes spezifischer Messtechnik bedarf. Das Ergebnis der Studie zeigt deutlich, dass sowohl die eingesetzte Hardware aktueller Smartphones und Tablets als auch die zur Verfügung stehen Programme bislang nicht den Ansprüchen einer Messung aus arbeitswissenschaftlicher Sicht entsprechen. Angesichts der Begeisterung vieler Gerätebesitzer in Kombination mit der Unkenntnis tatsächlicher Fähigkeiten solcher Apps ist es dringend notwendig, Aufklärungsarbeit zu leisten. Unabhängig von diesen Analyseergebnissen sollte die Chance betrachtet werden, dass durch zertifizierte messtechnische Erweiterungen von Smartphones eine engmaschigere und einfachere Überprüfung ergonomischer Arbeitsbedingungen möglich ist. Da es sich bei Smartphones vordergründig um Geräte zur Aufbereitung von Informationen handelt, verweist die Studie auf die Kopplung geeigneter Messsonden mit einem Smartphone. In dieser Kombination könnten Messsysteme zur Arbeitssystembeurteilung mit integrierter Anleitung entstehen, welche es vor allem ermöglichen, nicht nur korrekt zu messen, sondern die Ergebnisse auch richtig zu interpretieren und einzuordnen.
Hintergrund: Die COVID-19(„coronavirus disease 2019“)-Pandemie hat die Ad-hoc-Digitalisierung an Hochschulen vorangetrieben. Zugleich stand die digitale Hochschullehre vor der Herausforderung der Ausgestaltung der Lehre im Zusammenhang mit den vorbestehenden Ressourcen, der digitalen und didaktischen Kompetenzen sowie der zur Verfügung stehenden technischen Infrastruktur.
Ziel der Arbeit/Fragestellung: Das Ziel der Umfrage war die Einschätzung der digitalen Lehre, die die Präsenzlehre infolge der COVID-19-Pandemie zum großen Teil bzw. gänzlich ersetzt hat, aus der Perspektive der Lehrenden in Public Health, Medizin und Pflege.
Material und Methode: Die Querschnitterhebung fand online von Juni bis August 2020 statt und die Daten wurden über www.soscisurvey.de erhoben. Die schriftliche Befragung wurde unter Mitgliedern der Deutschen Gesellschaft für Public Health (DGPH) und des Ausschusses Digitalisierung der Gesellschaft für medizinische Ausbildung (GMA) und der Sektionen Bildung und Beratung der Deutschen Gesellschaft für Pflegewissenschaft (DGP) sowie der Arbeitsgruppe Lehre der Deutschen Gesellschaft für Medizinische Soziologie (DGMS) durchgeführt (n = 100).
Ergebnisse: Bei der Nutzung der digitalen Technologien in den Veranstaltungen rangieren auf der obersten Stelle Präsentationstools, gefolgt von Lernmanagementsystemen, Videoangeboten sowie digitalen Texten. Die Teilnehmenden geben hinsichtlich der Nutzung unterschiedliche (Konferenz‑)Tools an. Das Erstellen von Lehrvideos bejahen 53 % der Befragten, Abstimmungstools) werden bis 50 % als unbekannt genannt. Als Herausforderungen werden digitale Infrastruktur der Hochschulen, fehlende didaktische Beratung/Unterstützung sowie rechtliche Fragen (Nutzungsrechte, Datenschutz) angegeben.
Schlussfolgerung: Neue Technologie werden vorwiegend für Wissenserwerb, Wissensvermittlung genutzt, selten zur Aktivierung von Studierenden und zur Gestaltung kollaborativer Lehr- und Lernarrangements sowie Neugestaltung von Lernaufgaben und Lernprozessen (individualisiertes Lernen). Welche der aktuell erprobten digitalen Lehr- und Lernformate zukünftig in der Hochschullehre zunehmend eingesetzt werden, hängt von vielen Faktoren ab, u. a. von digitaler Kompetenz sowie der Bereitschaft der Lehrenden und Lernenden die digitale Lernkultur mitzugestalten.
Background: Stroke is one of the most frequent causes of death in Germany and the developed countries. After a stroke, those affected often suffer particularly from functional motor restrictions of the upper extremities. Newer techniques such as the BCI-FES systems aim to establish a communication channel between the brain and external devices with a neuromuscular intervention. The electrical activity of the brain is measured, processed, translated into control signals and can then be used to control an application.
Methods: As a mixed-methods design (exploratory design), eight guideline-based expert interviews were conducted first. For the quantitative expert survey, 95 chief physicians from the field of neuromedicine in rehabilitation facilities nationwide were subsequently invited to participate in an online survey.
Results: In our data analysis, we found that doctors are largely open-minded towards new technical rehabilitation systems. In addition to the proper functioning of the system, they consider the understanding of the functionality and the meaningfulness of the system to be particularly important. In addition, the system should be motivating for individuals, generate meaningful movements, be easy to use, evidence-based and quick to set up. Concerns were expressed regarding the understanding of the system’s processes, especially in the acute phase after a stroke, as well as the excessive expectation of results from the system on the part of the persons. The experts named stroke patients in rehabilitation phase C, which is about mobilization and recovery, as well as all persons who can understand the language requirements as benefiting groups of people.
Conclusion: The present study shows that more research should and must be done in the field of BCI-FES interfaces, and various development trends have been identified. The system has the potential to play a leading role in the rehabilitation of stroke patients in the future. Nevertheless, more work should be done on the improvement and implementation as well as the system’s susceptibility to interference in everyday patient life.
This paper presents numerical analysis of the discrete fundamental solution of the discrete Laplace operator on a rectangular lattice. Additionally, to provide estimates in interior and exterior domains, two different regularisations of the discrete fundamental solution are considered. Estimates for the absolute difference and lp‐estimates are constructed for both regularisations. Thus, this work extends the classical results in the discrete potential theory to the case of a rectangular lattice and serves as a basis for future convergence analysis of the method of discrete potentials on rectangular lattices.
Based on a real-world application in the semiconductor industry, this article models and discusses a hybrid flow shop problem with time dependencies and priority constraints. The analyzed problem considers a production where a large number of heterogeneous jobs are processed by a number of machines. The route that each job has to follow depends upon its type, and, in addition, some machines require that a number of jobs are combined in batches before starting their processing. The hybrid flow model is also subject to a global priority rule and a “same setup” rule. The primary goal of this study was to find a solution set (permutation of jobs) that minimizes the production makespan. While simulation models are frequently employed to model these time-dependent flow shop systems, an optimization component is needed in order to generate high-quality solution sets. In this study, a novel algorithm is proposed to deal with the complexity of the underlying system. Our algorithm combines biased-randomization techniques with a discrete-event heuristic, which allows us to model dependencies caused by batching and different paths of jobs efficiently in a near-natural way. As shown in a series of numerical experiments, the proposed simulation-optimization algorithm can find solutions that significantly outperform those provided by employing state-of-the-art simulation software.
Die Publikation untersucht die Einordnung der Führung in den Managementkontext und stellt das Konzept "Digital Leadership" als neue Managementkompetenz vor. Sie identifiziert Grundanforderungen an die Führungsrolle und betont die Herausforderungen für Führungskräfte in der digitalen Arbeitswelt. Dabei wird die Vielfalt der Grundanforderungen an die Führung aufgezeigt, indem die Wahl des Führungsstils, der Faktor „Motivation“ und das KLARA-Prinzip hervorgehoben werden. Der digitale Wandel erfordert die Anpassung der führenden Personen an die Herausforderungen der digitalen Transformation und die Fähigkeit, sich in verschiedene Führungsrollen hineinzuversetzen.
Die Publikation untersucht Home-Office im Kontext des "Digital Leadership", erörtert technische, organisatorische und führungspolitische Anforderungen und beleuchtet Chancen sowie Risiken dieser Arbeitsform. Es wird ein Überblick zur aktuellen Home-Office Situation in Deutschland gegeben. Zudem werden die Unternehmen "Compart AG" und "Microsoft" als Best-Practice-Beispiele hervorgehoben. Ziel ist es, die Voraussetzungen und erfolgreiche Umsetzungsmöglichkeiten des Home-Office zu analysieren.
Die Publikation analysiert die Arbeitssituation im Home-Office in Deutschland und identifiziert Anforderungen an Führungskräfte und Mitarbeiter. Führungskräfte sollten den partizipativen Führungsstil anwenden, die Fähigkeit zu motivieren besitzen sowie moderne Technologien nutzen. Mitarbeiter werden zu Eigenmotivation, Feedback und eigenverantwortlichem Arbeiten angehalten. Positive Aspekte der Telearbeit sind Flexibilität und Zeitersparnis, während fehlende Tätigkeitseignung und mangelnde Interaktion als Nachteile gelten. Die Handlungsempfehlungen, welche in Form von Checklisten gestaltet sind, beschreiben die Anforderungen an Führungskräfte und Mitarbeiter an die Telearbeit. Das Fazit in Kapitel drei rundet die Ergebnisse ab.
Das Hauptziel der Arbeit ist die Analyse der o.g. Anforderungen und die Ableitung von Handlungsempfehlungen für das Home-Office.
Die für die Planung des Materialflusses relevanten Fertigungsprozesse lassen sich sehr genau planen, beispielsweise über die Leistung der Maschine (Durchsatz je Zeiteinheit). Bei der Planung eines Projektes spielen logistische Prozesse, die zu den Kernprozessen eines Unternehmens gehören, eine wichtige Rolle. Jedoch werden sie meist nur grob terminiert und mit großen Puffern kalkuliert. Dies kann zu einer Verlängerung der Projektdauer führen. Für eine genauere Terminierung eines Projektes ist es daher entscheidend, die Dauer der logistischen Prozesse mindestens in dem Maße wie die Fertigungsprozesse zu ermitteln, um das Risiko einer Projektverzögerung zu minimieren.In diesem Beitrag wird deshalb eine Methode zur datenbasierten Schätzung von Prozessdauern mit dem Ziel der Wiederverwendung von Projektwissen vorgestellt, die es dem Projektmanagement ermöglichen soll, Dauern von logistischen Prozessen präziser zu schätzen als das aktuell basierend auf Erfahrungswissen erfolgt. Besonderes Augenmerk liegt dabei auf der Herleitung der Entwurfsaktivitäten. Durch die Anwendung der Methode soll das Projektmanagement von einer genaueren, datenbasierten Schätzung von (Logistik‑)Prozessdauern profitieren und so entstandenes Wissen über einen Ontologieansatz wiederverwenden können.
Dynamically loaded structures made of thermoplastic polymers have been extensively exploited in several demanding industries. Due to the viscoelastic and thermal properties of thermoplastic polymers, self-heating is generally inevitable, especially during dynamic deformations at high frequencies. Therefore, the thermoplastic polyether ether ketone (PEEK), with its high temperature resistance and high specific strength, is a particularly ideal candidate for dynamically loaded applications. Using scanning laser Doppler vibrometry and infrared thermography, an experimental study of the vibration characteristics and the vibration-induced heating of flat-sheet PEEK specimens was carried out. The specimens were base-excited by means of a piezoelectric actuator at high frequencies in the range between 1 and 16 kHz. As a result, a maximum temperature rise of approximately 6.4 K was detected for the highest investigated excitation. A high correlation between the spatial distribution of the velocity along the beam’s axial direction and the resulting temperature increase was measured. To summarize, the occurring self-heating of PEEK due to the dissipation of vibrational energy has to be critically considered for dynamically loaded structural applications, especially areas with high displacement amplitudes, such as antinodes, which yield the highest temperature increase.
Models of artificial root canals are used in several fields of endodontic investigations and pre-clinical endodontic training. They allow the physical testing of dental treatments, the operating of instruments used and the interaction between these instruments and the tissues. Currently, a large number of different artificial root canal models exist whose geometry is created either on the basis of selected natural root canal systems or to represent individual geometrical properties. Currently, only a few geometric properties such as the root canal curvature or the endodontic working width are taken into consideration when generating these models. To improve the representational capability of the artificial root canal models, the aim of the current study is therefore to generate an artificial root canal based on the statistical evaluation of selected natural root canals. Here, the approach introduced by Kucher for determining the geometry of a root canal model is used, which is based on the measurement and statistical evaluation of the root canal center line’s curvatures and their cross-sectional dimensions. Using the example of unbranched distal root canals of mandibular molars (n = 29), an artificial root canal model representing the mean length, curvature, torsion and cross-sectional dimensions of these teeth could be derived.
Structures made of the thermoplastic polymer polyether ether ketone (PEEK) are widely used in dynamically-loaded applications due to their high-temperature resistance and high mechanical properties. To design these dynamic applications, in addition to the well-known stiffness and strength properties the vibration-damping properties at the given frequencies are required. Depending on the application, frequencies from a few hertz to the ultrasonic range are of interest here. To characterize the frequency-dependent behavior, an experimental approach was chosen and applied to a sample polymer PEEK. The test setup consists of a piezoelectrically driven base excitation of the polymeric specimen and the non-contact measurement of the velocity as well as the surface temperature. The beam’s bending vibrations were analyzed by means of the Timoshenko theory to determine the polymer’s storage modulus. The mechanical loss factor was calculated using the half-power bandwidth method. For PEEK and a considered frequency range of 1 kHz to 16 kHz, a storage modulus between 3.9 GPa and 4.2 GPa and a loss factor between 9 × 10−3 and 17 × 10−3 were determined. For the used experimental parameters, the resulting mechanical properties were not essentially influenced by the amplitude of excitation, the duration of excitation, or thermal degrad.ation due to self-heating, but rather slightly by the clamping force within the fixation area.
Lewis–Mogridge Points: A Nonarbitrary Method to Include Induced Traffic in Cost-Benefit Analyses
(2020)
We propose a new method to estimate benefits of road network improvements, which allows to include the induced demand without arbitrary assumptions. Instead of estimating induced demand (which is nontrivial and hardly possible in practice), we search for demand induction where initial benefits are mitigated to zero. Such approach allows to formulate a dual measure of benefit, covering both the potential benefits and the likelihood of consuming them by the induced traffic. We first estimate benefits of road network improvement assuming that traffic demand is fixed. Consequently, we find demand model configurations at which the benefits of the new investment become null, i.e., all the initial benefits are consumed by the traffic demand growth. We call such states of induced demand the Lewis–Mogridge points of the analysed improvement. We select the most probable of such points and use it to calculate the proposed novel indicator μ, for which the initial benefits (obtained under a fixed-demand assumption) are multiplied with a demand increase rate needed to consume them. We believe that such measure allows to include the critical phenomena of induced traffic and, at the same time, to overcome problems associated with reliable estimation of induced demand. As we illustrate with the case of two alternative road improvement schemes in Kraków, Poland, the proposed method allows to estimate maximal threshold of induced traffic and to select scenario more resilient to induced traffic.
Sometimes cranioplasty is necessary to reconstruct skull bone defects after a neurosurgical operation. If an autologous bone is unavailable, alloplastic materials are used. The standard technical approach for the fabrication of cranial implants is based on 3D imaging by computed tomography using the defect and the contralateral site. A new approach uses 3D surface scans, which accurately replicate the curvature of the removed bone flap. For this purpose, the removed bone flap is scanned intraoperatively and digitized accordingly. When using a design procedure developed for this purpose creating a patient-specific implant for each bone flap shape in short time is possible. The designed skull implants have complex free-form surfaces analogous to the curvature of the skull, which is why additive manufacturing is the ideal manufacturing technology here. In this study, we will describe the intraoperative procedure for the acquisition of scanned data and its further processing up to the creation of the implant.
Introduction
(2022)
This paper provides a critical reading of Janek Wasserman’s The Marginal Revolutionaries: How Austrian Economists Fought the War of Ideas. Wasserman depicts the evolution of the Austrian School from the 1860s until today, a particularly illuminating narrative for the readers of this journal. The breadth of portrayed economists, their cultural embeddedness in Austrian and US contexts, and the complexity of configurations across the school’s generations create a rich and readable story. The last third of the book suffers from allegations about the ideological agenda and institutional power of the Austrian economists which sometimes lack sufficient substantiation. The paper indicates how both in their theorizing and in their political activities, the Austrian economists can be seen as reformers instead of revolutionaries, and as constitutionalists instead of anti-democrats. Despite these disagreements, Wasserman’s portrayals evoke largely fair and challenging impulses both to scholars working in the Austrian research program and to those interested in the Austrian School’s long history, regardless of one’s ideological positions.
This paper embeds the early political economy of Friedrich August von Hayek in the intellectual milieu of German ordoliberalism. The urgency during the 1930s and 1940s to stabilize the disintegrating societal orders is identified as a crucial driver behind the parallelisms between Hayek and the ordoliberals. Their shared theoretical position is that in such moments, liberty can thrive sustainably only after a framework of general and stable rules has been established. Hayek’s proximity to ordoliberalism was most explicitly discernible in The Road to Serfdom and at the founding meeting of the Mont Pèlerin Society in 1947, culminating in the shared politico-economic vision of the competitive order. The contextual nature of Hayek’s ordoliberalism surfaced in the years after The Constitution of Liberty when his focus shifted, along with the postwar intellectual and institutional stabilization of the West: from how stable orders enable liberty, to how liberty enables the evolution of orders.
Hintergrund: Die Studienzeit ist eine Phase, in der die jungen Erwachsenen mit spezifischen Anforderungen konfrontiert werden. Studierende der Medizin gelten als besonders psychisch belastet. Untersuchungen, in denen sie diesbezüglich mit Studienfächern der gleichen Branche verglichen werden, sind jedoch rar.
Fragestellung: Ziel der Untersuchung war es, die psychische Gesundheit von Medizinstudierenden sowie von Gesundheits- und Pflegemanagementstudierenden zu untersuchen und zu vergleichen.
Material und Methoden: Untersucht wurden Studierende der Studiengänge Gesundheits- sowie Pflegemanagement (WHZ) und Medizinstudierende der (TU Dresden). Verschiedene Aspekte psychischer Gesundheit wurden mithilfe eines Online-Fragebogens erhoben. Dieser beinhaltete die Instrumente zur Erfassung der Prüfungsängstlichkeit (TAI-G-Kurzskala) und psychischen Belastung (BSI-18), sowie ein Item zur Ermittlung der subjektiv wahrgenommenen Studienbelastung. 258 Studierende nahmen an der Befragung teil.
Ergebnisse: Es konnten keine signifikanten Unterschiede hinsichtlich des Gesamtscores der Prüfungsängstlichkeit und der psychischen Belastung zwischen den Studierenden beider Studienfächer festgestellt werden. Dahingegen gaben Medizinstudierende an, dass sie im Vergleich zu Studierenden der anderen beiden Studienfächer eine signifikant höhere Studienbelastung wahrnehmen.
Schlussfolgerung: Die ermittelten Gesamtscores lagen teilweise über den Werten in vergleichbaren Studien. Die Studierenden sollten bereits präventiv unterstützt werden, um eigene Bewältigungsstrategien zu entwickeln. Nicht nur die Bereitstellung von Hilfen ist notwendig, sondern vielmehr das aktive Eingreifen mithilfe von gesundheitsfördernden Maßnahmen durch die Institution Hochschule, in die die Studierenden frühzeitig integriert werden sollten.
The science of ergonomics studies the conditions and effects of human labour in order to obtain rules for assessment and design. As working life changes, the general working conditions also change dynamically. The causes of such change processes are changes in working and lifestyle, human-technology-interaction, working time, as well as the demands on flexibility, mobility, decision-making skills and self-organization. The consequences of this development are a constant increase in the complexity of work-related requirements. The burdens associated with work can no longer be considered in a situational and detached way, as in many classical methods of work analysis, but should be taken into account in their holistic effect of mutual relations.
This article theoretically and empirically deals first with the question of whether the use of wearables provides support and assistance for the analysis of working conditions. Second it asks whether the application of wearables is a way to investigate complex stress conditions more effectively and whether it might supplement, substitute or further develop established and esteemed methods of work system analysis.
The research was carried out for the selection of optimal options for the heat supply of multi-apartment buildings, taking as an example several new buildings in Yerevan. The purpose of the study is to confirm the choice of the best method of providing heat in apartment complexes. It was used to calculate and analyze the energy-economic and operational-technical indicators of individual heating boilers, small centralized systems, and hybrid systems to solve this problem. The calculations considered both natural gas tariffs and fluctuations in the value of the Armenian dram against the US dollar. The value of 1 kWh of thermal energy or specific heat capacity has been determined as an important criterion for choosing the most efficient method of heat supply, considering the careful analysis of almost all variable factors.
Multiplikatorenkonzepte zu Stress- und Emotionsregulation im Rettungsdienst – ein Scoping-Review
(2024)
Hintergrund: Beschäftigte im Rettungsdienst sind einem erhöhten Risiko ausgesetzt, psychische Beeinträchtigungen zu entwickeln, da sie in ihrem Berufsalltag hohen körperlichen und emotionalen Stressoren ausgesetzt werden. Der Umgang mit diesen Stressoren stellt eine wichtige Ressource dar, um im Sinne der Salutogenese eine Bewältigung vorzunehmen. Damit die Förderung der Stress- und Emotionsregulation nicht nur auf einer Verhaltensebene wirksam wird, bieten sich Multiplikatorenkonzepte mit einer verhältnisbezogenen Verzahnung in die Arbeitssysteme an.
Ziel der Arbeit: Die Überprüfung der verfügbaren Evidenz von Multiplikatorenkonzepten zur Stress- und Emotionsregulation im Rettungsdienst ist das Ziel des Scoping-Reviews.
Material und Methoden: Die Übersicht orientiert sich inhaltlich am Modell der Salutogenese und methodisch am Konzept des Joanna Briggs Institute zur Durchführung von Scoping-Reviews. Die Recherche basierte auf den Suchoberflächen PubMed sowie PubPsych (alle Evidenzquellen) und erstreckte sich auf deutsch- und englischsprachige Literatur im Zeitraum von 1997 bis 2023. Alle Schritte der Datensichtung und -extraktion wurden von zwei Reviewern unabhängig voneinander durchgeführt.
Ergebnisse: Für die Überprüfung der verfügbaren Evidenz wurden insgesamt 22.345 Datensätze identifiziert und gesichtet. Abschließend konnten vier Volltexte eingeschlossen werden. Die Interventionen richten sich neben Mitarbeitenden des Rettungsdiensts auch an andere Berufsgruppen. Alle Trainings sind modular aufgebaut. Die psychosozialen Widerstandsressourcen sind vielfältig. In drei von vier Studien können kleine Ergebnisse belegt werden; eine Intervention erhöht die Selbstwirksamkeit der Teilnehmenden.
Diskussion: Es gibt weltweit keine spezifischen Konzepte, die sich explizit an Mitarbeitende des Rettungsdiensts richten. Gezielte Interventionen sind aufgrund der hohen Belastungen der Berufsgruppe erforderlich.
Die Automobilindustrie befindet sich seit Jahren im Ausnahmezustand, da der Wechsel von einer Einheitsantriebsart hin zu einem Mix an Antriebsarten parallel zu globalen Krisen bewältigt werden muss. Der vorliegende Beitrag liefert dazu beispielhafte Betrachtungen zur indikativen Bewertung der gegensätzlichen Produktionsstrategien Mix- oder sortenreiner Produktion von Fahrzeugen mit alternativen und konventionellen Antrieben. Die Erkenntnisse können genutzt werden, um Modelle zur Wahl der richtigen Produktionsstrategien abzuleiten.
Die Automobilproduktion steht aktuell vor der Herausforderung, einen sich weiter diversifizierenden Antriebsmix effizient zu produzieren. Der vorliegende Beitrag erläutert die grundsätzlichen Einflüsse alternativer Antriebsarten auf die Fahrzeugproduktion, welche mithilfe umfangreicher Experteninterviews ermittelt wurden. Diese Erkenntnisse können genutzt werden, um langfristig die richtigen Produktionsstrategien für die Gestaltung effizienter Produktionsnetzwerke abzuleiten.
Effect of acoustic excitation on fiber-reinforced polypropylene and the influence on melt viscosity
(2021)
The paper describes a novel technological approach to influencing the rheological properties of thermoplastic materials exposed to acoustic energy. The flow behavior of polypropylene with different mass percentages of glass fibers is investigated in a parallel plate rheometer under high-frequency longitudinal excitation. The influence of oscillation frequency on the melt viscosity is explained by means of shear thinning criteria. The dependence of the oscillation shape using sinusoidal excitation on shear thinning as a function of different fiber reinforcement percentages is also investigated. A phenomenological view describes the mutually influencing parameters with regard to different material compositions and different excitation frequencies over the time course of the rheometric measurement. Interacting relationships are analyzed and discussed and the potential of the actuator system to influence the plastic melt is worked out. Based on this, a technological approach follows which describes the transfer of an oscillating mold surface to plastics processing methods, which, especially in the case of energy-intensive injection molding technology, leads to the expectation of possible resource efficiency in energy and material.
This article reconstructs the path of the German economist Friedrich A. Lutz (1901–75) to American economics. The correspondence with his former teacher Walter Eucken, the founder of the Freiburg school, constitutes a crucial yet unexplored source for the article. Through Lutz's case, this article demonstrates the growing gulf between German and Anglo-Saxon economics during the late 1930s. In his native Germany, Lutz was trained in methodologically and institutionally focused economics, which differed fundamentally from the mathematical economics dominating Anglo-Saxon academia. He realized that an academic career in the United States would be impossible if he did not adapt to the new methods and if he did not abandon the methods of the German tradition. This gave rise to his internal Methodenstreit. After his emigration in 1938, he constantly experienced doubts and tensions because he was convinced that without considering institutions, mathematical economics could never explain the occurrence and essence of macroeconomic phenomena. Despite his stellar career at Princeton, it was only after his move to Zurich in 1953, where he taught history and theory of socioeconomics for the rest of his life, that Lutz could reconcile this internal Methodenstreit.
Context: VR as an application to enhance well-being is sparsely researched in the elderly population. The aim of the pilot study was to analyze the effect of 360° videos of different categories on the state of mind of seniors in nursing facilities. Furthermore, for the implementation in everyday life, the usability of the system and the experience for seniors should be evaluated.
Methods: The VR experience was used as a supplement to existing care services in three facilities on eight subjects. Mood state was assessed using the Questionnaire for the Assessment of Happiness before and after the intervention. Demographic data and technology acceptance were collected beforehand. After the intervention, subjects were interviewed about confounding factors and side effects, and nursing home staff were interviewed about the usability of the system and the organizational concept of implementation.
Results: There was a positive effect on state of mind. Gender and spatial mobility turned out to be influencing factors. Categories containing people, animals and action achieved the highest increases in the state of mind. Interest in using technical devices correlated negatively with the change in mood state. None of the subjects found the VR goggles distracting or reported motion sickness. Very good usability was indicated by the employees.
Conclusion: A very high willingness to use this technology was found among nursing staff and residents. The tendencies of the positive effect of 360° videos on the state of mind, as well as differentiation based on the mentioned characteristics gender and spatial mobility, should be verified by a larger sample to empirically validate the use of this technology to increase the quality of life.
Der General
(2022)