scholarly journals Detection and Quantification of Delamination Failures in Marine Composite Bulkheads via Vibration Energy Variations

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2843
Author(s):  
Cristobal Garcia ◽  
Alfonso Jurado ◽  
Oscar Zaba ◽  
Publio Beltran

This paper proposes a new vibration-based structural health monitoring method for the identification of delamination defects in composite bulkheads used in small-length fiber-based ships. The core of this work is to find out if the variations of vibration energy can be efficiently used as a key performance indicator for the detection and quantification of delamination defects in marine composite bulkheads. For this purpose, the changes of vibrational energy exerted by delamination defects in sandwich and monolithic composite panel bulkheads with different types of delamination phenomenon are investigated using a non-destructive test. Experiments show that the overall vibration energy of the bulkheads is directly dependent on the damage conditions of the specimens and therefore, the variations of this parameter are a good indicator of the incorporation of delamination defects in composite bulkheads. Additionally, the overall vibration energy changes also give interesting information about the severity of the delamination defect in the panels. Hence, this methodology based on vibratory energy can be used to accurately determine delamination defects in medium-sized composite bulkheads with the advantages of being a simple and cost-effective approach. The findings of this research possess important applications for the identification of delamination failures in composite components such as bulkheads, turbine blades, and aircraft structures, among others.

2020 ◽  
Vol 64 (1-4) ◽  
pp. 201-210
Author(s):  
Yoshikazu Tanaka ◽  
Satoru Odake ◽  
Jun Miyake ◽  
Hidemi Mutsuda ◽  
Atanas A. Popov ◽  
...  

Energy harvesting methods that use functional materials have attracted interest because they can take advantage of an abundant but underutilized energy source. Most vibration energy harvester designs operate most effectively around their resonant frequency. However, in practice, the frequency band for ambient vibrational energy is typically broad. The development of technologies for broadband energy harvesting is therefore desirable. The authors previously proposed an energy harvester, called a flexible piezoelectric device (FPED), that consists of a piezoelectric film (polyvinylidene difluoride) and a soft material, such as silicon rubber or polyethylene terephthalate. The authors also proposed a system based on FPEDs for broadband energy harvesting. The system consisted of cantilevered FPEDs, with each FPED connected via a spring. Simply supported FPEDs also have potential for broadband energy harvesting, and here, a theoretical evaluation method is proposed for such a system. Experiments are conducted to validate the derived model.


2019 ◽  
Vol 118 (6) ◽  
pp. 90-93
Author(s):  
L. Terina Grazy ◽  
Dr.G. Parimalarani

E-commerce is a part of Internet Marketing. The arrival of Internet made the world very simple and dynamic in all the areas. Internet is the growing business as a result most of the people are using it in their day to day life. E-commerce is attractive and efficient way for both buyers and sellesr as it reduce cost, time and energy for the buyer. No surprise the insurance sector has become quite active within the internet sphere. Most insurance companies are offering policies to be brought online and also the portals for paying premiums. It actually saves from hassles involved in going to an insurance office and spend hours to get the insurance work done. Insurance has become an important and crucial aspect of life. Online insurance is the best and most cost effective approach of taking the insurance deal. This paper focused on influence of online marketing on the insurance industry in India, usage of internet in India , the internet penetration in India and the online sale of insurance product by the insurance sector.


Author(s):  
Yana van der Meulen Rodgers

Chapter 7 concludes by highlighting the three biggest messages from the analysis presented in this book: (1) the global gag rule has failed to achieve its goal of reducing abortions; (2) restrictive legislation is associated with more unsafe abortions; and (3) the expanded global gag rule is likely to have negative repercussions across a range of health outcomes for women, children, and men. They are simple but powerful messages that should be heard by policymakers over the voices calling for an ideologically based policy that fails to achieve its desired outcome. The chapter closes with a more constructive and cost-effective approach for US family-planning assistance that targets integrated reproductive health services.


2021 ◽  
Vol 10 (5) ◽  
pp. 971
Author(s):  
Kristoff Hammerich ◽  
Jens Pollack ◽  
Alexander F. Hasse ◽  
André El Saman ◽  
René Huber ◽  
...  

Background: A major disadvantage of current spacers for two-stage revision total knee arthroplasty (R-TKA) is the risk of (sub-) luxation during mobilization in the prosthesis-free interval, limiting their clinical success with detrimental consequences for the patient. The present study introduces a novel inverse spacer, which prevents major complications, such as spacer (sub-) luxations and/or fractures of spacer or bone. Methods: The hand-made inverse spacer consisted of convex tibial and concave femoral components of polymethylmethacrylate bone cement and was intra-operatively molded under maximum longitudinal tension in 5° flexion and 5° valgus position. Both components were equipped with a stem for rotational stability. This spacer was implanted during an R-TKA in 110 knees with diagnosed or suspected periprosthetic infection. Postoperative therapy included a straight leg brace and physiotherapist-guided, crutch-supported mobilization with full sole contact. X-rays were taken before and after prosthesis removal and re-implantation. Results: None of the patients experienced (sub-) luxations/fractures of the spacer, periprosthetic fractures, or soft tissue compromise requiring reoperation. All patients were successfully re-implanted after a prosthesis-free interval of 8 weeks, except for three patients requiring an early exchange of the spacer due to persisting infection. In these cases, the prosthetic-free interval was prolonged for one week. Conclusion: The inverse spacer in conjunction with our routine procedure is a safe and cost-effective alternative to other articulating or static spacers, and allows crutch-supported sole contact mobilization without major post-operative complications. Maximum longitudinal intra-operative tension in 5° flexion and 5° valgus position appears crucial for the success of surgery.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4545
Author(s):  
Sudharsan Sadhasivam ◽  
Omer Barda ◽  
Varda Zakin ◽  
Ram Reifen ◽  
Edward Sionov

Patulin (PAT) and citrinin (CTN) are the most common mycotoxins produced by Penicillium and Aspergillus species and are often associated with fruits and fruit by-products. Hence, simple and reliable methods for monitoring these toxins in foodstuffs are required for regular quality assessment. In this study, we aimed to establish a cost-effective method for detection and quantification of PAT and CTN in pome fruits, such as apples and pears, using high-performance liquid chromatography (HPLC) coupled with spectroscopic detectors without the need for any clean-up steps. The method showed good performance in the analysis of these mycotoxins in apple and pear fruit samples with recovery ranges of 55–97% for PAT and 84–101% for CTN, respectively. The limits of detection (LOD) of PAT and CTN in fruits were 0.006 µg/g and 0.001 µg/g, while their limits of quantification (LOQ) were 0.018 µg/g and 0.003 µg/g, respectively. The present findings indicate that the newly developed HPLC method provides rapid and accurate detection of PAT and CTN in fruits.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 918
Author(s):  
Xingzhe Cai ◽  
Meng Wang ◽  
Yucong Jiang ◽  
Changhu Wang ◽  
David W. Ow

Cadmium pollution threatens food safety and security by causing health issues and reducing farmland availability. Engineering genetic changes in crop plants to lower Cd accumulation can be a cost-effective approach to address this problem. Previously, we reported that a rice line, 2B, which expresses a truncated version of OsO3L2 had reduced Cd accumulation throughout the plant, including in seed. However, downstream events caused by expression of this gene were not known. In this study, RNA-seq was used to identify differentially expressed genes between the wild type and 2B rice with or without Cd treatment, leading to the study of an ABC transporter gene, OsABCG48 (ATP-Binding Cassette transporter G family member 48). Heterologous expression of OsABCG48 conferred tolerance to Cd in Schizosaccharomyces pombe, Arabidopsis and rice. Moreover, overexpressing OsABCG48 in rice lowered root Cd accumulation that was associated with more extensive lateral root development. These data suggest that OsABCG48 might have applications for engineering low-Cd rice.


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