scholarly journals Identification of Optimal Process Parameter Settings Based on Manufacturing Performance for Fused Filament Fabrication of CFR-PEEK

2020 ◽  
Vol 10 (13) ◽  
pp. 4630
Author(s):  
Kijung Park ◽  
Gayeon Kim ◽  
Heena No ◽  
Hyun Woo Jeon ◽  
Gül E. Okudan Kremer
Keyword(s):  
Layer Thickness ◽  
Optimal Parameter ◽  
Lower Layer ◽  
Critical Role ◽  
Performance Measure ◽  
Fused Filament Fabrication ◽  
Trade Offs ◽  
Manufacturing Performance ◽  
Overall Performance ◽  
The Impact

Fused filament fabrication (FFF) has been proven to be an effective additive manufacturing technique for carbon fiber reinforced polyether–ether–ketone (CFR-PEEK) due to its practicality in use. However, the relationships between the process parameters and their trade-offs in manufacturing performance have not been extensively studied for CFR-PEEK although they are essential to identify the optimal parameter settings. This study therefore investigates the impact of critical FFF parameters (i.e., layer thickness, build orientation, and printing speed) on the manufacturing performance (i.e., printing time, dimensional accuracy, and material cost) of CFR-PEEK outputs. A full factorial design of the experiments is performed for each of the three sample designs to identify the optimal parameter combinations for each performance measure. In addition, multiple response optimization was used to derive optimal parameter settings for the overall performance. The results show that the optimal parameter settings depend on the performance measures regardless of the designs, and that the layer thickness plays a critical role in the performance trade-offs. In addition, lower layer thickness, horizontal orientation, and higher speed form the optimal settings to maximize the overall performance. The findings from this study indicate that FFF parameter settings for CFR-PEEK should be identified through multi-objective decision making that involves conflicts between the operational objectives for the parameter settings.

An Empirical Analysis of FII Movement and Currency Value in India

2015 ◽  
pp. 207-217
Author(s):  
Saurabh Sen ◽  
Ruchi L. Sen
Keyword(s):  
Exchange Rate ◽  
Exchange Rates ◽  
Critical Role ◽  
Institutional Investment ◽  
Currency Futures ◽  
Overall Performance ◽  
Foreign Institutional Investors ◽  
Us Dollar ◽  
The Impact ◽  
The Relationship

India opened its stock market to foreign investors in September 1992 and has received portfolio investment from foreigners in the form of foreign institutional investment in equities and other markets including derivatives. It has emerged as one of the most influential groups to play a critical role in the overall performance of the Indian economy. The liberalization of FII flows into the Indian capital market since 1993 has had a significant impact on the economy. With increased volatility in exchange rate and to mitigate the risk arising out of excess volatility, currency futures were introduced in India in 2008, which is considered a second important structural change. This chapter examines the impact of the Foreign Institutional Investors (FIIs) on the exchange rate and analyzes the relationship between FII and Indian Rupee-US Dollar exchange rates.

scholarly journals Specialization and Performance: Evidence from NCAA 4 × 400 m Relay Times

Economies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 96
Author(s):  
Candon Johnson ◽  
Robert Schultz ◽  
Joshua C. Hall
Keyword(s):  
Performance Measure ◽  
Division I ◽  
Division Iii ◽  
Overall Performance ◽  
The Difference ◽  
And Performance ◽  
Using Data ◽  
The Impact ◽  
Better Than

This paper investigates the impact of having open 400 meter (400 m) runners on NCAA relay teams. Using data from 2012–2016 containing the top 100 4 × 400 m in each NCAA Division relay times for each year, it is found that more 400 m specialists lead to an increase in the overall performance of the team, measured by a decrease in relay times. The effect is examined across Division I–III NCAA track teams. The results are consistent across each division. We view this as a test of the role of specialization on performance. Using runners who specialize in 400 m races should increase overall team performance as long as specialization does not lead to an inefficient allocation of team human capital. An additional performance measure is used examining the difference between projected and actual relay times. Divisions I and II are found to perform better than projected with an increase in 400 m runners, but there is no effect found in Division III.

Process–Property Relationships for Fused Filament Fabrication on Preexisting Polymer Substrates

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Harry A. Pierson ◽  
Bharat Chivukula
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Layer Thickness ◽  
Process Parameters ◽  
Optimal Parameter ◽  
Fused Filament Fabrication ◽  
Highly Sensitive ◽  
Raster Angle ◽  
Process Property ◽  
Five Axis

Recent advances in fused filament fabrication (FFF), such as five-axis printing, patching existing parts, and certain hybrid manufacturing processes, involve printing atop a previously manufactured polymer substrate. The success of these technologies depends upon the bond strength between the substrate and the newly added geometry. ANOVA and response surface methods were used to determine the effect of three process parameters on bond tensile strength: surface roughness, layer thickness, and raster angle. Experimental results indicate that the process–property relationships are not identical to those found in single, continuous FFF operations, and that the physical bonding mechanisms may also be different. Bond strength was found to be highly sensitive to surface roughness and layer thickness, and distinct optimal parameter settings exist. These results represent a first step toward understanding bond strength in such circumstances, allowing manufacturers to intelligently select process parameters for the production of both the substrate and the secondary geometry.

scholarly journals Influence of Process Parameters on Tensile Strength of Additive Manufactured PLA Parts using Taguchi Method

2019 ◽  
Vol 8 (3) ◽  
pp. 7635-7639
Keyword(s):  
Tensile Strength ◽  
Layer Thickness ◽  
Fused Deposition Modeling ◽  
Optimal Parameter ◽  
Fused Filament Fabrication ◽  
Influence Of Process Parameters ◽  
Layer Height ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Nozzle Temperature

Influence of layer thickness nozzle temperature and angle on tensile strength of PLA fabricated with FDM (FFF) was experimentally investigated. Polylactic Acid (PLA) is a semi-crystalline and bio-friendly thermoplastic polymer has identified as important material in different applications due to its mechanical characteristics. Fused Deposition Modeling (FDM) is a one of the proved technology in Fused Filament Fabrication (FFF) technique in additive manufacturing process. In present investigation different specimens were fabricated using FDM technique with different layer height and different layer angles for finding influence of these manufacturing parameters on tensile strength of the specimen. Specimens were fabricated and tested as per ASTM D638 standard. It is clearly observed that tensile strength is more for +450 /-450 layer angle than the +00 /-0 0 layer angle for a given layer height(h=0.10 mm, h=0.15mm and h=0.20mm).The TAGUCHI analysis is carried with nozzle temperature, layer thickness and angle finding optimal values. It has been observed that, the optimal parameter is angle, which is equal to 30 0 .the ANOVA variation of angle layer with tensile strength has been observed that 18.10-31.90.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

The Impact of Bar Service Operation Practices on Organizational Performance in Indian Hotel Industry

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohinder C. Dhiman ◽  
Abhishek Ghai
Keyword(s):  
Organizational Performance ◽  
Hotel Industry ◽  
Demographic Variables ◽  
Study Results ◽  
Service Operation ◽  
Managerial Implications ◽  
Overall Performance ◽  
The Impact ◽  
The Relationship ◽  
Bivariate Test

The paper has a two fold purpose - examine the impact of bar service operation practices (BSOP) on organizational performance (OP) and study the relationship between organizational performance and demographic variables. Based on a survey of 362 bar managers perceptions on the impact of bar service operation practices on organizational performance were assessed by 59 practices and 6 demographic variables. Bivariate test and ANOVA were employed to test the working hypothesis in the study. Results indicated that there is a positive relationship between the bar service operation practices and organizational performance. Further, the results indicate some practical and managerial implications to improve organizational overall performance.

scholarly journals Carbon Dynamics in the Northeastern Qinghai–Tibetan Plateau from 1990 to 2030 Using Landsat Land Use/Cover Change Data

2020 ◽  
Vol 12 (3) ◽  
pp. 528 ◽  
Author(s):  
Jingye Li ◽  
Jian Gong ◽  
Jean-Michel Guldmann ◽  
Shicheng Li ◽  
Jie Zhu
Keyword(s):  
Land Use ◽  
Tibetan Plateau ◽  
Carbon Storage ◽  
Sharp Decrease ◽  
Total Carbon ◽  
Qinghai Lake ◽  
Lake Basin ◽  
Ecosystem Carbon ◽  
Trade Offs ◽  
The Impact

Land use/cover change (LUCC) has an important impact on the terrestrial carbon cycle. The spatial distribution of regional carbon reserves can provide the scientific basis for the management of ecosystem carbon storage and the formulation of ecological and environmental policies. This paper proposes a method combining the CA-based FLUS model and the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to assess the temporal and spatial changes in ecosystem carbon storage due to land-use changes over 1990–2015 in the Qinghai Lake Basin (QLB). Furthermore, future ecosystem carbon storage is simulated and evaluated over 2020–2030 under three scenarios of natural growth (NG), cropland protection (CP), and ecological protection (EP). The long-term spatial variations in carbon storage in the QLB are discussed. The results show that: (1) Carbon storage in the QLB decreased at first (1990–2000) and increased later (2000–2010), with total carbon storage increasing by 1.60 Tg C (Teragram: a unit of mass equal to 1012 g). From 2010 to 2015, carbon storage displayed a downward trend, with a sharp decrease in wetlands and croplands as the main cause; (2) Under the NG scenario, carbon reserves decrease by 0.69 Tg C over 2020–2030. These reserves increase significantly by 6.77 Tg C and 7.54 Tg C under the CP and EP scenarios, respectively, thus promoting the benign development of the regional ecological environment. This study improves our understanding on the impact of land-use change on carbon storage for the QLB in the northeastern Qinghai–Tibetan Plateau (QTP).

scholarly journals The lung–gut axis during viral respiratory infections: the impact of gut dysbiosis on secondary disease outcomes

2021 ◽  
Author(s):  
Valentin Sencio ◽  
Marina Gomes Machado ◽  
François Trottein
Keyword(s):  
Gut Microbiota ◽  
Bacterial Infections ◽  
Respiratory Infections ◽  
Critical Role ◽  
Good Health ◽  
Disease Outcomes ◽  
And Function ◽  
Viral Respiratory Infections ◽  
The Impact ◽  
Viral Respiratory

AbstractBacteria that colonize the human gastrointestinal tract are essential for good health. The gut microbiota has a critical role in pulmonary immunity and host’s defense against viral respiratory infections. The gut microbiota’s composition and function can be profoundly affected in many disease settings, including acute infections, and these changes can aggravate the severity of the disease. Here, we discuss mechanisms by which the gut microbiota arms the lung to control viral respiratory infections. We summarize the impact of viral respiratory infections on the gut microbiota and discuss the potential mechanisms leading to alterations of gut microbiota’s composition and functions. We also discuss the effects of gut microbial imbalance on disease outcomes, including gastrointestinal disorders and secondary bacterial infections. Lastly, we discuss the potential role of the lung–gut axis in coronavirus disease 2019.

scholarly journals Methionine Diet Evoked Hyperhomocysteinemia Causes Hippocampal Alterations, Metabolomics Plasma Changes and Behavioral Pattern in Wild Type Rats

2021 ◽  
Vol 22 (9) ◽  
pp. 4961
Author(s):  
Maria Kovalska ◽  
Eva Baranovicova ◽  
Dagmar Kalenska ◽  
Anna Tomascova ◽  
Marian Adamkov ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Brain Area ◽  
Critical Role ◽  
Cerebrovascular Diseases ◽  
Behavioral Pattern ◽  
Cell Physiology ◽  
Male Wistar Rats ◽  
High Level ◽  
Hippocampal Alterations ◽  
The Impact

L-methionine, an essential amino acid, plays a critical role in cell physiology. High intake and/or dysregulation in methionine (Met) metabolism results in accumulation of its intermediate(s) or breakdown products in plasma, including homocysteine (Hcy). High level of Hcy in plasma, hyperhomocysteinemia (hHcy), is considered to be an independent risk factor for cerebrovascular diseases, stroke and dementias. To evoke a mild hHcy in adult male Wistar rats we used an enriched Met diet at a dose of 2 g/kg of animal weight/day in duration of 4 weeks. The study contributes to the exploration of the impact of Met enriched diet inducing mild hHcy on nervous tissue by detecting the histo-morphological, metabolomic and behavioural alterations. We found an altered plasma metabolomic profile, modified spatial and learning memory acquisition as well as remarkable histo-morphological changes such as a decrease in neurons’ vitality, alterations in the morphology of neurons in the selective vulnerable hippocampal CA 1 area of animals treated with Met enriched diet. Results of these approaches suggest that the mild hHcy alters plasma metabolome and behavioural and histo-morphological patterns in rats, likely due to the potential Met induced changes in “methylation index” of hippocampal brain area, which eventually aggravates the noxious effect of high methionine intake.

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