Residual strength of laminated composites after impact

2010 ◽  
Vol 45 (9) ◽  
pp. 1031-1043 ◽  
Author(s):  
V. Kamala Kannan ◽  
A. Rajadurai ◽  
B. Nageswara Rao
Keyword(s):  
Residual Strength ◽  
Laminated Composites ◽  
Empirical Relation ◽  
Laminated Composite ◽  
Fracture Analysis ◽  
Static Strength ◽  
Impact Loads ◽  
Strength Assessment ◽  
The Impact ◽  
Made In

This article deals with the residual strength assessment on completely as well as partially penetrated laminated composites due to impact loads by idealizing the damage locations as holes and cracks. Modifications are made in the inherent flaw model (IFM) of Waddoups, Eisenman, and Kaminski (known as the WEK model) to correlate the fracture data of laminated composites. For velocities above complete penetration, the residual strength is identical to the static strength of the laminated composite with a hole having the same diameter as the impacting particle. For this case, the inherent flaw length ahead of the notch is correlated with notched and un-notched strengths through fracture parameters. For the case where the impact velocities are less than the penetration velocity, an empirical relation is proposed following the IFM for the residual strength in terms of kinetic energy of the impact. The adequacy of the modified IFM is demonstrated through comparison of fracture analysis results with tensile, compressive, and impact fracture strength of laminated composites containing holes and cracks.

scholarly journals An Effectiveness Trial of STEADI in an Outpatient, Primary Care Practice

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 774-774
Author(s):  
David Rein ◽  
Madeleine Hackney ◽  
Michele Dougherty ◽  
Camille Vaughan ◽  
Laurie Imhof ◽  
...  
Keyword(s):  
Primary Care ◽  
Medication Review ◽  
Primary Care Practice ◽  
Controlled Trial ◽  
Care Practice ◽  
Strength Assessment ◽  
Randomized Controlled ◽  
Study Team ◽  
One Year ◽  
The Impact

Abstract The STEADI Options trial uses a randomized, controlled-trial design to assess the effectiveness and cost-effectiveness of the STEADI Initiative . Beginning March, 2020, we will randomize 3,000 adults ≥ 65 years of age at risk for falls seen in an Emory Clinic primary care practice to: (1) full STEADI; (2) a STEADI-derived gait, balance, and strength assessment with physical therapy referrals; (3) a STEADI-derived medication review and management; or (4) usual care. This presentation will discuss decisions made by the study team to facilitate implementation of STEADI including electronically conducting screening prior to the date of encounter, the use of dedicated nursing staff to conduct assessments, implementation of strength, balance, orthostatic hypotension, and vision testing, methods to facilitate medication review, and communication of assessment information to providers. The results from this study will be used to estimate the impact of STEADI on falls, service utilization, and costs over one year.

scholarly journals Comparative study of elastic properties and mode I fracture energy of carbon nanotube/epoxy and carbon fibre/epoxy laminated composites

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Jyotikalpa Bora ◽  
Sushen Kirtania
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fibre ◽  
Fracture Energy ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Laminated Composite ◽  
Fe Analysis ◽  
Mode I ◽  
Mode I Fracture

Abstract A comparative study of elastic properties and mode I fracture energy has been presented between conventional carbon fibre (CF)/epoxy and advanced carbon nanotube (CNT)/epoxy laminated composite materials. The volume fraction of CNT fibres has been considered as 15%, 30%, and 60% whereas; the volume fraction of CF has been kept constant at 60%. Three stacking sequences of the laminates viz.[0/0/0/0], [0/90/0/90] and [0/30/–30/90] have been considered in the present analysis. Periodic microstructure model has been used to calculate the elastic properties of the laminated composites. It has been observed analytically that the addition of only 15% CNT in epoxy will give almost the same value of longitudinal Young’s modulus as compared to the addition of 60% CF in epoxy. Finite element (FE) analysis of double cantilever beam specimens made from laminated composite has also been performed. It has been observed from FE analysis that the addition of 15% CNT in epoxy will also give almost the same value of mode I fracture energy as compared to the addition of 60% CF in epoxy. The value of mode I fracture energy for [0/0/0/0] laminated composite is two times higher than the other two types of laminated composites.

Handshake antimicrobial stewardship as a model to recognize and prevent diagnostic errors

Diagnosis ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Justin B. Searns ◽  
Manon C. Williams ◽  
Christine E. MacBrayne ◽  
Ann L. Wirtz ◽  
Jan E. Leonard ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Interrater Reliability ◽  
Diagnostic Errors ◽  
Diagnostic Error ◽  
Primary Treatment ◽  
Treatment Team ◽  
Children's Hospital ◽  
Children’S Hospital ◽  
The Impact ◽  
Made In

AbstractObjectivesFew studies describe the impact of antimicrobial stewardship programs (ASPs) on recognizing and preventing diagnostic errors. Handshake stewardship (HS-ASP) is a novel ASP model that prospectively reviews hospital-wide antimicrobial usage with recommendations made in person to treatment teams. The purpose of this study was to determine if HS-ASP could identify and intervene on potential diagnostic errors for children hospitalized at a quaternary care children’s hospital.MethodsPreviously self-identified “Great Catch” (GC) interventions by the Children’s Hospital Colorado HS-ASP team from 10/2014 through 5/2018 were retrospectively reviewed. Each GC was categorized based on the types of recommendations from HS-ASP, including if any diagnostic recommendations were made to the treatment team. Each GC was independently scored using the “Safer Dx Instrument” to determine presence of diagnostic error based on a previously determined cut-off score of ≤1.50. Interrater reliability for the instrument was measured using a randomized subset of one third of GCs.ResultsDuring the study period, there were 162 GC interventions. Of these, 65 (40%) included diagnostic recommendations by HS-ASP and 19 (12%) had a Safer Dx Score of ≤1.50, (Κ=0.44; moderate agreement). Of those GCs associated with diagnostic errors, the HS-ASP team made a diagnostic recommendation to the primary treatment team 95% of the time.ConclusionsHandshake stewardship has the potential to identify and intervene on diagnostic errors for hospitalized children.

Effects of hostile solutions on the static and dynamic behavior of carbon/epoxy composites

2021 ◽  
pp. 002199832110200
Author(s):  
H Ersen Balcıoğlu ◽  
Raif Sakin ◽  
Halit Gün
Keyword(s):  
Bending Strength ◽  
Laminated Composites ◽  
Fatigue Behavior ◽  
Laminated Composite ◽  
Test Sample ◽  
Solution Concentration ◽  
Static Stability ◽  
Three Point Bending ◽  
Sem Image ◽  
Solution Type

Fiber-reinforced laminated composite is often used in harsh environments that may affect their static stability and long-term durability as well as residual strength. In this study, the effect of heavy chemical environments such as acid and alkaline and retaining time for these environments on flexural strength and flexural fatigue behavior of carbon/epoxy laminated composites were investigated. In this context, carbon/epoxy was retained into an acidic and alkaline solution having 5%, 15%, and 25% concentration by weight for 1–4 months. Fatigue behavior of carbon/epoxy was determined under dynamic flexural load, which corresponds to 80%, 70%, 60%, 50%, and 40% of static three-point bending strength of the test sample. SEM image of damaged specimens was taken to describe the failure mechanism of damage which occurs after fatigue. Also, to better understand environmental condition on the fatigue life, results were compared with results of carbon/epoxy laminated composites, which were not retained into any environments (unretained). The test results showed that the solution type, solution concentration, and retaining time caused noticeable changes in the static and dynamic strengths of carbon/epoxy laminated composites.

scholarly journals Optimal Solutions for the Use of Sewage Sludge on Agricultural Lands

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 585
Author(s):  
Catalina Iticescu ◽  
Puiu-Lucian Georgescu ◽  
Maxim Arseni ◽  
Adrian Rosu ◽  
Mihaela Timofti ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Agricultural Production ◽  
Agricultural Land ◽  
Chemical Characteristics ◽  
Optimal Solutions ◽  
Physico Chemical ◽  
Agricultural Areas ◽  
The Impact ◽  
Made In

The use of sewage sludge in agriculture decreases the pressure on landfills. In Romania, massive investments have been made in wastewater treatment stations, which have resulted in the accumulation of important quantities of sewage sludge. The presence of these sewage sludges coincides with large areas of degraded agricultural land. The aim of the present article is to identify the best technological combinations meant to solve these problems simultaneously. Adapting the quality and parameters of the sludge to the specificity of the land solves the possible compatibility problems, thus reducing the impact on the environment. The physico-chemical characteristics of the fermented sludge were monitored and optimal solutions for their treatment were suggested so as to allow that the sludge could be used in agriculture according to the characteristics of the soils. The content of heavy metals in the sewage sludge was closely monitored because the use of sewage sludge as a fertilizer does not allow for any increases in the concentrations of these in soils. The article identifies those agricultural areas which are suitable for the use of sludge, as well as ways of correcting some parameters (e.g., pH), which allow the improvement of soil quality and obtained higher agricultural production.

scholarly journals Monitoring the Impact of the Large Building Investments on the Neighborhood

2021 ◽  
Vol 11 (14) ◽  
pp. 6537
Author(s):  
Marian Łupieżowiec
Keyword(s):  
Groundwater Level ◽  
Soil Improvement ◽  
Deep Excavation ◽  
Large Area ◽  
Safety Measures ◽  
High Rise ◽  
The Impact ◽  
Large Building ◽  
Additional Safety ◽  
Made In

The article presents the concept of monitoring buildings and infrastructure elements located near large construction investments (the construction of high-rise buildings of the Oak Terraces housing estate in Katowice and the construction of a tunnel under the roundabout in Katowice along the intercity express road DTŚ). The impacts include deep excavation, lowering of the groundwater level over a large area, and dynamic influences related to the use of impact methods of soil improvement. The presented monitoring includes observation of the groundwater level with the use of piezometers, geodetic measurements of settlement and inclinations, as well as the measurement of vibration amplitudes generated during the works involving shocks and vibrations. It was also important to observe the development of cracks on the basis of a previously made inventory of damage. The results of the monitoring allow corrections to be made in the technology of works (e.g., reduction of vibration amplitudes, application of additional protections at excavations, etc.) or the use additional safety measures. Currently, there are also monitoring systems used during the operation of completed facilities.

Platform Capitalism ‘Made in China’? Intelligent Manufacturing, Taobao Villages and the Restructuring of Work

2019 ◽  
Vol 24 (2) ◽  
pp. 199-217 ◽  
Author(s):  
Boy Lüthje
Keyword(s):  
Intelligent Manufacturing ◽  
Value Chains ◽  
Policy Recommendations ◽  
Employment Policy ◽  
Social Shaping Of Technology ◽  
Social Shaping ◽  
Made In China ◽  
The Impact ◽  
Conditions Of Employment ◽  
Made In

The article examines the development of advanced digital manufacturing (as outlined in the ‘Made-in-China 2025’ government plan) from the perspective of the changing socio-technical paradigms of production. The analysis focuses on the transformations of value chains and work, based on theories of social shaping of technology, regulation theory and regimes of production. Analytically, the author proposes to distinguish between ‘production-driven’ and ‘distribution-driven’ pathways of manufacturing digitalisation. The transformation of semi-rural industrial areas (‘Taobao villages’, named after China’s largest e-commerce platform Taobao) into mass production clusters for e-commerce is depicted as a paradigmatic model of distribution-driven transformation and as a characteristic Chinese strategy in this field. The article examines the impact on industry supply chains and work, leading to ever-more precarious conditions of employment. Policy recommendations focus on local strategies to stabilise supply chain structures and working conditions, as an alternative to the present top-down approaches to manufacturing modernisation in China.

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