scholarly journals Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

2020 ◽  
Author(s):  
Diana G. San Benito Pastor ◽  
Devaiah Nalianda ◽  
Vishal Sethi ◽  
Ron Midgley ◽  
Andrew Rolt ◽  
...  
Keyword(s):  
System Design ◽  
Load Capacity ◽  
Engine Performance ◽  
Maximum Load ◽  
Transmission System ◽  
Published Data ◽  
Planetary Gearbox ◽  
Open Rotor ◽  
Parametric Analyses ◽  
The Impact

Abstract This study introduces an innovative approach to sizing a differential planetary gearbox for a counter-rotating open rotor application. An updated methodology is proposed for the design of maximum load capacity gears based on the power transmitted, durability and space-envelope requirements of the application. The reported methodology has been validated by comparing the results to published data, demonstrating a maximum difference of 0.6% in geometry. Parametric analyses have also been performed to assess the impact of the design assumptions on gearbox dimensional trends. The proposed methodology enables the assessment of the impact of the preliminary transmission system design on engine performance and general arrangement. The characteristics of the gearset lead to an unequal torque split between output shafts (i.e. the propeller shafts). Given the design assumptions made, the study indicates that valid torque ratios would lie between 1.1 and 1.33. The impact of the torque ratio on the size of the gearbox has been analysed for equal rotational speeds and for different speeds between the output shafts. The study established that the transmission system design needs to be considered prior to selection of the torque ratio at engine design level.

Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Electric Vehicles ◽  
Thermal Load ◽  
Load Capacity ◽  
Maximum Load ◽  
Induction Machines ◽  
Electric Machines ◽  
Model Parameters ◽  
Dynamic Operating ◽  
The Impact

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.

Challenges in Validating a Thermo-Hydrodynamic Gas Foil Bearing Model

2020 ◽  
Author(s):  
Hanns Michel ◽  
Robert Liebich
Keyword(s):  
Thermal Model ◽  
High Speed ◽  
Load Capacity ◽  
Maximum Load ◽  
Fine Tuning ◽  
Flow Paths ◽  
Operational Conditions ◽  
Foil Bearings ◽  
Wide Range ◽  
The Impact

Abstract Gas foil bearings (GFBs) are suitable for high speed and temperature applications where conventional lubricated bearing solution are not feasible. This requires the pre-diction of bearing temperatures and thus a thermal model considering the heat genera-tion and heat flow paths in the bearing. The effects of two different bump foil stiffness (Iordanoff and Le Lez [1,2]) and heat transfer models (a simplified and a detailed one) are presented in respect to measured temperatures from literature [3,4]. The compari-son is drawn over a wide range of operational conditions as well as measuring posi-tions, which in such detail has not been shown before. While good agreement is found for some of the conditions and positions, only reasonable agreement is found for others. The deviations and difficulties in validating a thermal model against experiments are highlighted in a discussion about various temperature influencing parameters, especial-ly concerning the change of clearance during operation. In conclusion it is found, that the models are able to predict temperatures reasonably well, but require delicate fine-tuning to achieve these results. Finally, the impact of the temperature on the maximum load capacity at a range of speeds is shown in a comparison between an isothermal calculation and one with temperature consideration.

Lighting energy performance determination in office environments through implementation of EN 15193-1 for Turkey

2021 ◽  
pp. 147715352098742
Author(s):  
FŞ Yilmaz
Keyword(s):  
System Design ◽  
Architectural Design ◽  
Office Buildings ◽  
Energy Requirements ◽  
System Control ◽  
Lighting System ◽  
Artificial Lighting ◽  
Design Alternatives ◽  
Lighting Energy ◽  
The Impact

Office buildings are building typologies where efficient and optimal use of lighting energy is crucial while providing comfortable visual environments. The purpose of this study is to explore the impact of diverse architectural design alternatives on lighting energy requirements and lighting energy saving possibilities through a case study. In this study, a total of 3888 design alternatives are investigated in a comparative way in terms of daylighting system design alternatives, artificial lighting system design scenarios, artificial lighting system control types and shading system control options. Introducing the adaptation process of the EN 15193-1:2017 standard for Turkey’s specific climatic and geographical conditions and considering diverse lighting design scenarios, results of this parametric study aim to underline the significance of architectural design strategies in office buildings for the reduction of lighting energy requirements.

scholarly journals Impact of pharmacist-conducted anticoagulation patient education and telephone follow-up on transitions of care: a randomized controlled trial

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lamis R. Karaoui ◽  
Elsy Ramia ◽  
Hanine Mansour ◽  
Nisrine Haddad ◽  
Nibal Chamoun
Keyword(s):  
Tertiary Care ◽  
Intervention Group ◽  
Bleeding Event ◽  
Transitions Of Care ◽  
Control Group ◽  
Published Data ◽  
Post Discharge ◽  
Readmission Rates ◽  
The Impact

Abstract Background There is limited published data in Lebanon evaluating the impact of supplemental education for anticoagulants use, especially DOACs, on clinical outcomes such as bleeding. The study aims to assess the impact of pharmacist-conducted anticoagulation education and follow-up on bleeding and readmission rates. Methods This study was a randomized, non-blinded interventional study conducted between August 2017 and July 2019 in a tertiary care teaching Lebanese hospital. Participants were inpatients ≥18 years discharged on an oral anticoagulant for treatment. Block randomization was used. The control group received the standard nursing counseling while the intervention group additionally received pharmacy counseling. Phone call follow-ups were done on day 3 and 30 post-discharge. Primary outcomes included readmission rates and any bleeding event at day 3 and 30 post-discharge. Secondary outcomes included documented elements of education in the medical records and reported mortality upon day 30 post-discharge. Results Two hundred patients were recruited in the study (100 patients in each study arm) with a mean age of 73.9 years. In the pharmacist-counseled group, more patients contacted their physician within 3 days (14% versus 4%; p = 0.010), received explicit elements of education (p < 0.001) and documentation in the chart was better (p < 0.05). In the standard of care group, patients were more aware of their next physician appointment date (52% versus 31%, p < 0.001). No difference in bleeding rates at day 3 and 30 post-discharge was observed between the groups. Conclusions Although pharmacist-conducted anticoagulation education did not appear to reduce bleeding or readmission rates at day 30, pharmacist education significantly increased patient communication with their providers in the early days post-discharge. Trial registration Lebanon Clinical Trial Registry LBCTR2020033424. Retrospectively registered. Date of registration: 06/03/2020.

scholarly journals Mycosporine-Like Amino Acids from Red Macroalgae: UV-Photoprotectors with Potential Cosmeceutical Applications

2021 ◽  
Vol 11 (11) ◽  
pp. 5112
Author(s):  
Julia Vega ◽  
Geniane Schneider ◽  
Bruna R. Moreira ◽  
Carolina Herrera ◽  
José Bonomi-Barufi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
High Performance ◽  
Nitrogen Availability ◽  
Antioxidant Properties ◽  
Published Data ◽  
Diverse Group ◽  
Red Macroalgae ◽  
Thermo Stability ◽  
The Impact

Macroalgae belong to a diverse group of organisms that could be exploited for biomolecule application. Among the biocompounds found in this group, mycosporine-like amino acids (MAAs) are highlighted mainly due to their photoprotection, antioxidant properties, and high photo and thermo-stability, which are attractive characteristics for the development of cosmeceutical products. Therefore, here we revise published data about MAAs, including their biosynthesis, biomass production, extraction, characterization, identification, purification, and bioactivities. MAAs can be found in many algae species, but the highest concentrations are found in red macroalgae, mainly in the order Bangiales, as Porphyra spp. In addition to the species, the content of MAAs can vary depending on environmental factors, of which solar radiation and nitrogen availability are the most influential. MAAs can confer photoprotection due to their capacity to absorb ultraviolet radiation or reduce the impact of free radicals on cells, among other properties. To extract these compounds, different approaches can be used. The efficiency of these methods can be evaluated with characterization and identification using high performance liquid chromatography (HPLC), associated with other apparatus such as mass spectrometry (MS) and nuclear magnetic resonance (NMR). Therefore, the data presented in this review allow a broad comprehension of MAAs and show perspectives for their inclusion in cosmeceutical products.

scholarly journals The Irish National Adverse Event Study-2 (INAES-2): longitudinal trends in adverse event rates in the Irish healthcare system

2021 ◽  
pp. bmjqs-2020-011122 ◽  
Author(s):  
Warren Connolly ◽  
Natasha Rafter ◽  
Ronan M Conroy ◽  
Cornelia Stuart ◽  
Anne Hickey ◽  
...  
Keyword(s):  
Adverse Event ◽  
Adverse Events ◽  
Positive Impact ◽  
Retrospective Chart Review ◽  
Published Data ◽  
National Programmes ◽  
Event Rates ◽  
Hospital Associated Infections ◽  
Design And Methods ◽  
The Impact

ObjectivesTo quantify the prevalence and nature of adverse events in acute Irish hospitals in 2015 and to assess the impact of the National Clinical Programmes and the National Clinical Guidelines on the prevalence of adverse events by comparing these results with the previously published data from 2009.Design and methodsA retrospective chart review of 1605 admissions to eight Irish hospitals in 2015, using identical methods to those used in 2009.ResultsThe percentage of admissions associated with one or more adverse events was unchanged (p=0.48) at 14% (95% CI=10.4% to 18.4%) in 2015 compared with 12.2% (95% CI=9.5% to 15.5%) in 2009. Similarly, the prevalence of preventable adverse events was unchanged (p=0.3) at 7.4% (95% CI=5.3% to 10.5%) in 2015 compared with 9.1% (95% CI=6.9% to 11.9%) in 2009. The incidence densities of preventable adverse events were 5.6 adverse events per 100 admissions (95% CI=3.4 to 8.0) in 2015 and 7.7 adverse events per 100 admissions (95% CI=5.8 to 9.6) in 2009 (p=0.23). However, the percentage of preventable adverse events due to hospital-associated infections decreased to 22.2% (95% CI=15.2% to 31.1%) in 2015 from 33.1% (95% CI=25.6% to 41.6%) in 2009 (p=0.01).ConclusionAdverse event rates remained stable between 2009 and 2015. The percentage of preventable adverse events related to hospital-associated infection decreased, which may represent a positive impact of the related national programmes and guidelines.

scholarly journals Design and Analysis of an Aerostatic Pad Controlled by a Diaphragm Valve

Lubricants ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 47
Author(s):  
Federico Colombo ◽  
Luigi Lentini ◽  
Terenziano Raparelli ◽  
Andrea Trivella ◽  
Vladimir Viktorov
Keyword(s):  
Sensitivity Analysis ◽  
High Precision ◽  
Load Capacity ◽  
Design Procedure ◽  
Maximum Load ◽  
Air Gap ◽  
Diaphragm Valve ◽  
Compensation Methods ◽  
Aerostatic Bearings ◽  
Gap Height

Because of their distinctive characteristics, aerostatic bearings are particularly suitable for high-precision applications. However, because of the compressibility of the lubricant, this kind of bearing is characterized by low relative stiffness and poor damping. Compensation methods represent a valuable solution to these limitations. This paper presents a design procedure for passively compensated bearings controlled by diaphragm valves. Given a desired air gap height at which the system should work, the procedure makes it possible to maximize the stiffness of the bearing around this value. The designed bearings exhibit a quasi-static infinite stiffness for load variation ranging from 20% to almost 50% of the maximum load capacity of the bearing. Moreover, the influence of different parameters on the performance of the compensated pad is evaluated through a sensitivity analysis.

scholarly journals Isolation and structural elucidation of dimeric epigallocatechin-3-gallate autoxidation products and their antioxidant capacity

2021 ◽  
Author(s):  
Julian Alfke ◽  
Uta Kampermann ◽  
Svetlana Kalinina ◽  
Melanie Esselen
Keyword(s):  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Cd Spectroscopy ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Published Data ◽  
Dietary Polyphenols ◽  
Cellular Effects ◽  
The Impact

AbstractDietary polyphenols like epigallocatechin-3-gallate (EGCG)—which represents the most abundant flavan-3-ol in green tea—are subject of several studies regarding their bioactivity and health-related properties. On many occasions, cell culture or in vitro experiments form the basis of published data. Although the stability of these compounds is observed to be low, many reported effects are directly related to the parent compounds whereas the impact of EGCG degradation and autoxidation products is not yet understood and merely studied. EGCG autoxidation products like its dimers theasinensin A and D, “P2” and oolongtheanin are yet to be characterized in the same extent as their parental polyphenol. However, to investigate the bioactivity of autoxidation products—which would minimize the discrepancy between in vitro and in vivo data—isolation and structure elucidation techniques are urgently needed. In this study, a new protocol to acquire the dimers theasinensin A and D as well as oolongtheanin is depicted, including a variety of spectroscopic and quadrupole time-of-flight high-resolution mass spectrometric (qTOF-HRMS) data to characterize and assign these isolates. Through nuclear magnetic resonance (NMR) spectroscopy, polarimetry, and especially circular dichroism (CD) spectroscopy after enzymatic hydrolysis the complementary atropisomeric stereochemistry of the isolated theasinensins is illuminated and elucidated. Lastly, a direct comparison between the isolated EGCG autoxidation products and the monomer itself is carried out regarding their antioxidant properties featuring Trolox equivalent antioxidant capacity (TEAC) values. These findings help to characterize these products regarding their cellular effects and—which is of special interest in the flavonoid group—their redox properties.

News personalization for peace: how algorithmic recommendations can impact conflict coverage

2019 ◽  
Vol 30 (3) ◽  
pp. 309-328 ◽  
Author(s):  
Mariella Bastian ◽  
Mykola Makhortykh ◽  
Tom Dobber
Keyword(s):  
Conceptual Framework ◽  
System Design ◽  
News Media ◽  
Content Distribution ◽  
Content Type ◽  
Constructive Conflict ◽  
Peace Journalism ◽  
Negative Impacts ◽  
The Impact ◽  
War Reporting

PurposeThe purpose of this paper is to develop a conceptual framework for assessing what are the possibilities and pitfalls of using algorithmic systems of news personalization – i.e. the tailoring of individualized news feeds based on users’ information preferences – for constructive conflict coverage in the context of peace journalism, a journalistic paradigm calling for more diversified and creative war reporting.Design/methodology/approachThe paper provides a critical review of existing research on peace journalism and algorithmic news personalization, and analyzes the intersections between the two concepts. Specifically, it identifies recurring pitfalls of peace journalism based on empirical research on constructive conflict coverage and then introduces a conceptual framework for analyzing to what degree these pitfalls can be mediated – or worsened – through algorithmic system design.FindingsThe findings suggest that AI-driven distribution technologies can facilitate constructive war reporting, in particular by countering the effects of journalists’ self-censorship and by diversifying conflict coverage. The implementation of these goals, however, depends on multiple system design solutions, thus resonating with current calls for more responsible and value-sensitive algorithmic design in the domain of news media. Additionally, our observations emphasize the importance of developing new algorithmic literacies among journalists both to realize the positive potential of AI for promoting peace and to increase the awareness of possible negative impacts of new systems of content distribution.Originality/valueThe article particle is the first to provide a comprehensive conceptualization of the impact of new content distribution techniques on constructive conflict coverage in the context of peace journalism. It also offers a novel conceptual framing for assessing the impact of algorithmic news personalization on reporting traumatic and polarizing events, such as wars and violence.

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