scholarly journals Analysis of the mechanical composite properties of ii-chamber variations in the closed injection pultrusion process

2021 ◽  
Author(s):  
Sebastian Strauß ◽  
Simon Boysen ◽  
Andreas Senz ◽  
Frederik Wilhelm ◽  
Niko Rilli

Pultrusion is an established and efficient process for producing continuous fiber-reinforced composites. The resin systems that are currently most frequently used are unsaturated polyesters and vinylesters. These have a long pot life, are well known, and have good processing properties. Highly reactive resins such as polyurethane (PU) and amine hardening epoxy have been in use for a few years. These resin classes are remarkable for their extended range of properties. This opens up new application fields for pultrusion technology but poses challenges for the processing technology. Short pot lives of just a few minutes require a modified process: closed injection pultrusion (CIP). Various approaches about the design and layout of the internal geometry of the injection and impregnation chambers (ii-chamber) are the subject of ongoing research. Numerous parameters influence the impregnation process in the ii-chamber and the quality of the resulting composite. In this study, two innovative, highly reactive resins for use in the pultrusion process were analyzed, both resins based on aliphatic polyurethanes. In phase 1 of the experiments, a commercial aliphatic polyurethane-system for pultrusion applications was used. In Phase 2, the recently developed bio-based aliphatic polyurethane-system for pultrusion applications was used for the study's main experiments. The aim of the study was to analyze the material and processing properties with various modifications of the impregnation setup. Therefore, a newly developed ii-chamber and die were tested. The ii-chamber was designed to enable easy adjustment of some of the main influencing parameters during the pultrusion process. A test strategy was developed to evaluate the properties of the composites. An assessment of the influence of the process- and die-based parameters should enable an evaluation of the optimal processing settings by analysis of the material characteristics. The most significant effect of variations in the pultrusion process was found in the interlaminar shear strength (ILSS). ILSS was analyzed for all process variations for both resin systems.

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 864
Author(s):  
Qingzheng Xu ◽  
Na Wang ◽  
Lei Wang ◽  
Wei Li ◽  
Qian Sun

Traditional evolution algorithms tend to start the search from scratch. However, real-world problems seldom exist in isolation and humans effectively manage and execute multiple tasks at the same time. Inspired by this concept, the paradigm of multi-task evolutionary computation (MTEC) has recently emerged as an effective means of facilitating implicit or explicit knowledge transfer across optimization tasks, thereby potentially accelerating convergence and improving the quality of solutions for multi-task optimization problems. An increasing number of works have thus been proposed since 2016. The authors collect the abundant specialized literature related to this novel optimization paradigm that was published in the past five years. The quantity of papers, the nationality of authors, and the important professional publications are analyzed by a statistical method. As a survey on state-of-the-art of research on this topic, this review article covers basic concepts, theoretical foundation, basic implementation approaches of MTEC, related extension issues of MTEC, and typical application fields in science and engineering. In particular, several approaches of chromosome encoding and decoding, intro-population reproduction, inter-population reproduction, and evaluation and selection are reviewed when developing an effective MTEC algorithm. A number of open challenges to date, along with promising directions that can be undertaken to help move it forward in the future, are also discussed according to the current state. The principal purpose is to provide a comprehensive review and examination of MTEC for researchers in this community, as well as promote more practitioners working in the related fields to be involved in this fascinating territory.


2021 ◽  
Author(s):  
A McCauley Massie ◽  
Jonathan Ebelhar ◽  
Kristen E Allen ◽  
Nicholas P DeGroote ◽  
Karen Wasilewski-Masker ◽  
...  

Abstract Background Children with brain and central nervous system (CNS) tumors experience substantial challenges to their quality of life during their disease course. These challenges are opportunities for increased subspecialty palliative care (PC) involvement. Palliative opportunities have been defined in the pediatric oncology population, but the frequency, timing, and factors associated with palliative opportunities in pediatric patients with CNS tumors are unknown. Methods A single-institution retrospective review was performed on children ages 0-18 diagnosed with a CNS tumor who died between 01/01/2012-11/30/2017. Nine palliative opportunities were defined prior to data collection (progression; relapse; admission for severe symptoms; intensive care admission; bone marrow transplant; phase 1 trial; hospice; do-not-resuscitate (DNR) order). Demographic, disease, treatment, palliative opportunity, and end-of-life data were collected. Opportunities were evaluated over quartiles from diagnosis to death. Results Amongst 101 patients with a median age at death of eight years (Interquartile range, IQR=8.0, range 0-22), there was a median of seven (IQR=6) palliative opportunities per patient, which increased closer to death. PC consultation occurred in 34 (33.7%) patients, at a median of 2.2 months before death, and was associated with having a DNR order (p=0.0028). Hospice was involved for 72 (71.3%) patients. Conclusion Children with CNS tumors suffered repeated events warranting PC yet received PC support only one-third of the time. Mapping palliative opportunities over the cancer course promotes earlier timing of PC consultation which can decrease suffering and resuscitation attempts at the end-of-life.


2021 ◽  
pp. 002193472110661
Author(s):  
Yatesha D. Robinson

The purpose of this exploratory study was to investigate whether intentional exposure to affirming messages via podcast would lead to improvement in subjective wellbeing in a sample of African American women. This two-part study used a mixed-methods design to measure subjective wellbeing using the Multicultural Quality of Life Index and a series of focus groups. During Phase 1, participants rated and discussed culturally relevant affirmations that informed the development of the podcast intervention used in Phase 2. The results revealed that stressors such as microaggressions, mental distress, and competing demands justified the need for support. Participants indicated that the podcast intervention was an enriching experience that illuminated the necessity of restorative practices that heal and revitalize the spirit. The intervention led to positive behavior change; and these results demonstrated the podcast benefits, suggesting that intentional exposure to positive messages may help some African American women cope with life stressors.


1995 ◽  
Vol 391 ◽  
Author(s):  
Larry M. Ting ◽  
G. Dixit ◽  
M. Jain ◽  
K. A. Littau ◽  
H. Tran ◽  
...  

AbstractIn this study, we have evaluated electromigration performance of W-plug vias, fabricated with process variations in via hole etching as well as in via barrier deposition, on a TiN(barrier)/AlCu/TiN metallization system. We found that via etch profile scheme as well as deposition conformity for via barrier can significantly affect W-plug via lifetimes. The results indicate that the quality of contact with AlCu layer of bottom level metal is a critical factor in determining via lifetime. Precise control of via etching or by use of conformal via barrier to ensure a good barrier between W-plug and the AlCu of bottom level metal is essential for achieving reliable via structures.


Author(s):  
Krzysztof Stachowiak ◽  
Piotr Zwierzykowski

The multicast quality of service-enabled routing is a computationally challenging task. Despite ongoing research efforts, the associated mathematical problems are still considered to be NP-hard. In certain applications, computational complexity of finding the optimal connection between a set of network devices may be a particularly difficult challenge. For example, connecting a small group of participants of a teleconference is not much more complex than setting up a set of mutual point-to-point connections. On the other hand, satisfying the demand for such services as IPTV, with their receivers constituting the majority of the network, requires applying appropriate optimization methods in order to ensure real system execution. In this paper, algorithms solving this class of problems are considered. The notion of multicast saturation is introduced to measure the amount of multicast participants relative to the entire network, and the efficiency of the analyzed algorithms is evaluated for different saturation degrees.


2005 ◽  
Vol 15 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Leo Liberti ◽  
Edoardo Amaldi ◽  
Francesco Maffioli ◽  
Nelson Maculan

The problem of finding a fundamental cycle basis with minimum total cost in a graph arises in many application fields. In this paper we present some integer linear programming formulations and we compare their performances, in terms of instance size, CPU time required for the solution, and quality of the associated lower bound derived by solving the corresponding continuous relaxations. Since only very small instances can be solved to optimality with these formulations and very large instances occur in a number of applications, we present a new constructive heuristic and compare it with alternative heuristics.


Author(s):  
Marilyn Rantz ◽  
G. F. Petroski ◽  
L. L. Popejoy ◽  
A. A. Vogelsmeier ◽  
K. E. Canada ◽  
...  

Abstract Objectives To measure the impact of advanced practice nurses (APRNs) on quality measures (QM) scores of nursing homes (NHs) in the CMS funded Missouri Quality Initiative (MOQI) that was designed to reduce avoidable hospitalizations of NH residents, improve quality of care, and reduce overall healthcare spending. Design A four group comparative analysis of longitudinal data from September 2013 thru December 2019. Setting NHs in the interventions of both Phases 1 (2012–2016) and 2 (2016–2020) of MOQI (n=16) in the St. Louis area; matched comparations in the same counties as MOQI NHs (n=27); selected Phase 2 payment intervention NHs in Missouri (n=24); NHs in the remainder of the state (n=406). Participants NHs in Missouri Intervention: Phase 1 of The Missouri Quality Initiative (MOQI), a Centers for Medicare and Medicaid (CMS) Innovations Center funded research initiative, was a multifaceted intervention in NHs in the Midwest, which embedded full-time APRNs in participating NHs to reduce hospitalizations and improve care of NH residents. Phase 2 extended the MOQI intervention in the original intervention NHs and added a CMS designed Payment Intervention; Phase 2 added a second group of NHs to receive the Payment. Intervention Only. Measurements Eight QMs selected by CMS for the Initiative were falls, pressure ulcers, urinary tract infections, indwelling catheters, restraint use, activities of daily living, weight loss, and antipsychotic medication use. For each of the monthly QMs (2013 thru 2019) an unobserved components model (UCM) was fitted for comparison of groups. Results The analysis of QMs reveals that that the MOQI Intervention + Payment group (group with the embedded APRNs) outperformed all comparison groups: matched comparison with neither intervention, Payment Intervention only, and remainder of the state. Conclusion These results confirm the QM analyses of Phase 1, that MOQI NHs with full-time APRNs are effective to improve quality of care.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 23-24
Author(s):  
Sylvia Von Mackensen ◽  
Pratima Chowdary ◽  
Sarah Mangles ◽  
Qifeng Yu ◽  
Baisong Mei ◽  
...  

Background: Fitusiran, an investigational RNA interference treatment for people with hemophilia A or B (PwH), with or without inhibitors, has shown dose-dependent lowering of antithrombin, increase in thrombin generation, and decrease in bleeding frequency in clinical trials. The novel mechanism of action and long pharmacodynamic effect enables once-monthly subcutaneous administration. This sustained hemostatic protection and less burdensome administration may improve patient-reported outcomes (PRO). Objective: To evaluate changes in PRO in terms of patient-relevant improvements in health-related quality of life (HRQoL) in PwH with inhibitors (PwHI) on prophylactic fitusiran treatment. Methods: Fitusiran was evaluated in a phase 1 dose-escalation study (NCT02035605) followed by a phase 2 open-label extension (OLE) study (NCT02554773) with monthly subcutaneous fixed doses of 50 mg or 80 mg. HRQoL was assessed using the Haem-A-QoL and the EuroQol 5 Dimensions (EQ-5D) questionnaires at baseline and at end of study in a cohort of 17 PwHI (Hemophilia A, n=15; Hemophilia B, n=2) from the phase 1 study. Results: Subjects previously treated on-demand or prophylactically had a mean (standard deviation [SD]) age of 34.6 (10.3) years and a mean (SD) number of bleeding episodes in the 6 months before baseline of 16.6 (10.7). Mean (SD) changes from baseline to end of study (day 84 or later) in Haem-A-QoL total (-9.2 [11.2]) and physical health (−12.3 [15.1]) domain scores suggest clinically meaningful improvement (lower scores indicate better HRQoL). Numeric reduction (i.e., improvement) in all other domains appeared to be dose-dependent (greater improvement in the 80 mg group) (Table 1). Changes in EQ-5D utility and EQ-VAS scores were not clinically meaningful. Further analyses in PwH with and without inhibitors from the phase 2 OLE will be presented. Conclusions: Fitusiran prophylaxis may improve HRQoL - particularly the Haem-A-QoL 'Physical health' domain (painful swelling, joint pain, pain with movement, difficulty walking, and time to get ready) as shown in a cohort of 17 PwHI . Additional analyses from ongoing OLE and phase 3 studies are planned to quantify the patient-relevant changes with fitusiran treatment in all hemophilia patients over time. Disclosures Von Mackensen: Sanofi, Bayer, Sobi, Chugai, Kedrion, Spark: Consultancy; Biotest, Sobi, CSL Behring: Honoraria; Novo Nordisk, Sobi: Research Funding. Chowdary:BioMarin: Honoraria; Bayer, CSL Behring, Freeline, Novo Nordisk, Pfizer and Sobi: Research Funding; Chugai, CSL Behring, Novo Nordisk, Pfizer, Roche, Sobi: Speakers Bureau; Bayer, Chugai, CSL Behring, Freeline, Novo Nordisk, Pfizer, Roche, Sanofi, Shire (Baxalta), Sobi, Spark: Membership on an entity's Board of Directors or advisory committees. Mangles:Roche, Takeda, Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sobi, Octapharma, Novo Nordisk, Shire and Roche/Chugai: Other: travel funding. Yu:Sanofi: Other: was an employee and stockholder of Sanofi, at the time of study; Albireo Pharmaceuticals, Inc: Current Employment. Mei:Sanofi: Current Employment, Current equity holder in publicly-traded company. Andersson:Sanofi: Current Employment, Current equity holder in publicly-traded company. Dasmahapatra:Sanofi: Current Employment, Current equity holder in publicly-traded company.


2013 ◽  
Vol 31 (9) ◽  
pp. 1239-1247 ◽  
Author(s):  
Monika L. Metzger ◽  
Lillian R. Meacham ◽  
Briana Patterson ◽  
Jacqueline S. Casillas ◽  
Louis S. Constine ◽  
...  

Purpose As more young female patients with cancer survive their primary disease, concerns about reproductive health related to primary therapy gain relevance. Cancer therapy can often affect reproductive organs, leading to impaired pubertal development, hormonal regulation, fertility, and sexual function, affecting quality of life. Methods The Children's Oncology Group Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancer (COG-LTFU Guidelines) are evidence-based recommendations for screening and management of late effects of therapeutic exposures. The guidelines are updated every 2 years by a multidisciplinary panel based on current literature review and expert consensus. Results This review summarizes the current task force recommendations for the assessment and management of female reproductive complications after treatment for childhood, adolescent, and young adult cancers. Experimental pretreatment as well as post-treatment fertility preservation strategies, including barriers and ethical considerations, which are not included in the COG-LTFU Guidelines, are also discussed. Conclusion Ongoing research will continue to inform COG-LTFU Guideline recommendations for follow-up care of female survivors of childhood cancer to improve their health and quality of life.


2021 ◽  
Author(s):  
Jacqueline Jonklaas

Abstract Hypothyroidism is a common endocrinopathy and levothyroxine is frequently prescribed. Despite the basic tenets of initiating and adjusting levothyroxine being agreed upon, there are many nuances and complexities to consistently maintaining euthyroidism. Understanding the impact of patient weight and residual thyroid function on initial levothyroxine dosage and consideration of age, co-morbidities, TSH goal, life stage, and quality of life as levothyroxine is adjusted can be challenging and continually evolving. As levothyroxine is a life-long medication it is important to avoid risks from periods of overtreatment or undertreatment. For the subset of patients not restored to baseline health with levothyroxine, causes arising from all aspects of the patient’s life (co-existent medical conditions, stressors, lifestyle, psychosocial factors) should be broadly considered. If such factors do not appear to be contributing, and biochemical euthyroidism has been successfully maintained, there may be benefit to a trial of combination therapy with levothyroxine and liothyronine. This is not supported by the majority of randomized clinical trials, but may be supported by other studies providing lower quality evidence and by animal studies. Given this discrepancy, it is important that any trial of combination therapy only be continued as long as a patient benefit is being enjoyed. Monitoring for adverse effects, particularly in older or frail individuals, is necessary and combination therapy should not be utilized during pregnancy. A sustained release liothyronine preparation has completed phase 1 testing and may soon be available for better designed and powered studies assessing whether combination therapy provides superior therapy for hypothyroidism.


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