scholarly journals Short and Long Term Measurements in Assessment of FRP Composite Footbridge Behavior

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 525 ◽  
Author(s):  
Mikołaj Miśkiewicz ◽  
Łukasz Pyrzowski ◽  
Bartosz Sobczyk
Keyword(s):  
Numerical Models ◽  
The Novel ◽  
Reinforced Plastics ◽  
Frp Composite ◽  
Novel Structure ◽  
Short And Long Term ◽  
Fiber Reinforced Plastics ◽  
Measurement Devices

The paper presents application of different sensors for the purpose of short and long term measurements, as well as a structural health monitoring (SHM) system to assess the behavior of a novel fiber reinforced plastics (FRP) composite footbridge. The aim is to present a thorough and concise description of these sensors networks and results gathered with their aid during in situ measurement of strains, displacements, and vibrations, as only a few works are available in this field. The bridge geometry, material solutions, and properties are described at first. Then the measurement devices composing the system and subsystems of sensors are elaborated on. Subsequently, the bridge research program is described and the results are shown and discussed. Finally, it is concluded that the use of selected sensors is helpful in assessment of the behavior of the novel structure, and moreover in validation of its numerical models. The collected data confirmed many assumptions made during the bridge design process and allowed us to accept it for exploitation.

Effect of long climatic ageing on the microstructure of the surface of сarbon-fiber-reinforced plastics on base epoxy matrix

2019 ◽  
pp. 157-169 ◽  
Author(s):  
I. S. Deev ◽  
E. V. Kurshev ◽  
S. L. Lonsky
Keyword(s):  
Climatic Factors ◽  
Temperate Climate ◽  
Fiber Reinforced ◽  
Humid Climate ◽  
Climatic Zones ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fiber Reinforced Plastics ◽  
Determining Factor

Studies and experimental data on the microstructure of the surface of samples of epoxy сarbon-fiber-reinforced plastics that have undergone long-term (up to 5 years) climatic aging in different climatic zones of Russia have been conducted: under conditions of the industrial zone of temperate climate (Moscow, MTsKI); temperate warm climate (Gelendzhik, GTsKI); a warm humid climate (Sochi, GNIP RAS). It is established that the determining factor for aging of carbon plastics is the duration of the complex effect of climatic factors: the longer the period of climatic aging, the more significant changes occur in the microstructure of the surface of the materials. The intensity of the aging process and the degree of microstructural changes in the surface of carbon plastics are affected by the features of the climatic zone. general regularities and features of the destruction of the surface of carbon plastics after a long-term exposure to climatic factors have been established on the basis of the analysis and systematization of the results of microstructural studies.

scholarly journals Design and Regulation of Novel MnFe2O4@C Nanowires as High Performance Electrode for Supercapacitor

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 777 ◽  
Author(s):  
Lei Geng ◽  
Fengfeng Yan ◽  
Chenhao Dong ◽  
Cuihua An
Keyword(s):  
Energy Density ◽  
Electric Conductivity ◽  
Power Density ◽  
High Performance ◽  
High Specific Capacitance ◽  
The Novel ◽  
Micro Emulsion ◽  
High Electric Conductivity

Bimetallic oxides have been considered as potential candidates for supercapacitors due to their relatively high electric conductivity, abundant redox reactions and cheapness. However, nanoparticle aggregation and huge volume variation during charging-discharging procedures make it hard for them to be applied widely. In this work, one-dimensional (1D) MnFe2O4@C nanowires were in-situ synthesized via a simply modified micro-emulsion technique, followed by thermal treatment. The novel 1D and core-shell architecture, and in-situ carbon coating promote its electric conductivity and porous feature. Due to these advantages, the MnFe2O4@C electrode exhibits a high specific capacitance of 824 F·g−1 at 0.1 A·g−1 and remains 476 F·g−1 at 5 A·g−1. After 10,000 cycles, the capacitance retention of the MnFe2O4@C electrode is up to 93.9%, suggesting its excellent long-term cycling stability. After assembling with activated carbon (AC) to form a MnFe2O4@C//AC device, the energy density of this MnFe2O4@C//AC device is 27 W·h·kg−1 at a power density of 290 W·kg−1, and remains at a 10 W·h·kg−1 energy density at a high power density of 9300 W·kg−1.

scholarly journals The coronavirus in the MENA region: Enhancing turbulence or mitigating conflicts?

European View ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 206-211
Author(s):  
Magnus Norell
Keyword(s):  
Middle East ◽  
The Novel ◽  
Crisis Preparedness ◽  
Mena Region ◽  
Existing Problems ◽  
Regional Conflicts ◽  
Current Trends ◽  
Short And Long Term ◽  
Novel Coronavirus

The novel coronavirus (COVID-19) pandemic has affected the countries in the Middle East and North Africa (MENA) region in different ways, and the varying political structures, economic conditions and civil-crisis preparedness of the states in this region have resulted in it being handled in a variety of ways too. Even if it is difficult to assess how the crisis has affected the MENA region in more detail due to the region’s general volatility and ongoing conflicts in Libya and Syria, current trends have so far not shown a diminution in regional conflicts. Nor have the pandemic’s consequences in the Middle East lessened Europe’s problems with the region. Thus the article argues that COVID-19 has not really led to a decrease in the conflicts and wars plaguing the MENA region, and that, therefore, the effects for Europe—both short- and long-term—will still be felt, as existing problems will continue to affect Europe.

scholarly journals Effect of cigarette smoking on nitric oxide, structural, and mechanical properties of mouse arteries

2006 ◽  
Vol 291 (5) ◽  
pp. H2354-H2361 ◽  
Author(s):  
X. Guo ◽  
M. J. Oldham ◽  
M. T. Kleinman ◽  
R. F. Phalen ◽  
G. S. Kassab
Keyword(s):  
Nitric Oxide ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cigarette Smoking ◽  
Coronary Arteries ◽  
Short And Long Term ◽  
By Products ◽  
Enos Protein

Cigarette smoking (CS) is a major risk factor for vascular disease. The aim of this study was to quantitatively assess the influence of CS on mouse arteries. We studied the effect of short-term (6 wk) and long-term (16 wk) CS exposure on structural and mechanical properties of coronary arteries compared with that of control mice. We also examined the reversibility of the deleterious effects of CS on structural [e.g., wall thickness (WT)], mechanical (e.g., stiffness), and biochemical [e.g., nitric oxide (NO) by-products] properties with the cessation of CS. The left and right coronary arteries were cannulated in situ and mechanically distended. The stress, strain, elastic modulus, and WT of coronary arteries were determined. Western blot analysis was used to analyze endothelial NO synthase (eNOS) in the femoral and carotid arteries of the same mice, and NO by-products were determined by measuring the levels of nitrite. Our results show that the mean arterial pressure was increased by CS. Furthermore, CS significantly increased the elastic modulus, decreased stress and strain, and increased the WT and WT-to-radius ratio compared with those of control mice. The reduction of eNOS protein expression was found only after long-term CS exposure. Moreover, the NO metabolite was markedly decreased in CS mice after short- and long-term exposure of CS. These findings suggest that 16 wk of CS exposure can cause an irreversible deterioration of structural and elastic properties of mouse coronary arteries. The decrease in endothelium-derived NO in CS mice was seen to significantly correlate with the remodeling of arterial wall.

Development of shrinkage resistant microfibre-reinforced cement-based composites

2012 ◽  
Vol 2 (2) ◽  
Author(s):  
P. Hamedanimojarrad ◽  
G. Adam ◽  
A. Ray ◽  
P. Thomas ◽  
K. Vessalas
Keyword(s):  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Crack Size ◽  
Moisture Loss ◽  
The Novel ◽  
Total Shrinkage ◽  
Low Concentrations ◽  
Reinforced Cement ◽  
Short And Long Term

AbstractDifferent shrinkage types may cause serious durability dilemma on restrained concrete parts due to crack formation and propagation. Several classes of fibres are used by concrete industry in order to reduce crack size and crack number. In previous studies, most of these fibre types were found to be effective in reducing the number and sizes of the cracks, but not in shrinkage strain reduction. This study deals with the influence of a newly introduced type of polyethylene fibre on drying shrinkage reduction. The novel fibre is a polyethylene microfibre in a new geometry, which is proved to reduce the amount of total shrinkage in mortars. This special hydrophobic polyethylene microfibre also reduces moisture loss of mortar samples. The experimental results on short and long-term drying shrinkage as well as on several other properties are reported. The hydrophobic polyethylene microfibre showed promising improvement in shrinkage reduction even at very low concentrations (0.1% of cement weight).

Short- and Long-term Comparison between Photorefractive Keratectomy and Laser In Situ Keratomileusis

Cornea ◽  
2009 ◽  
Vol 28 (Suppl 1) ◽  
pp. S41-S45
Author(s):  
Takashi Miyai ◽  
Kazunori Miyata ◽  
Ryohei Nejima ◽  
Masato Honbo ◽  
Keiichiro Minami ◽  
...  
Keyword(s):  
Laser In Situ Keratomileusis ◽  
Photorefractive Keratectomy ◽  
Short And Long Term

Modulation of central glucocorticoid receptors in short- and long-term experimental hypothyroidism

2015 ◽  
Author(s):  
Elena Nikolopoulou ◽  
Dimitris Mytilinaios ◽  
Dimitris Spinos ◽  
Nikitas – Apollon Panagiotopoulos ◽  
George P. Chrousos
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Affinity ◽  
Glucocorticoid Receptors ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Receptor Number ◽  
Short And Long Term

Aim: Normal adrenocortical responsiveness to stress involves glucocorticoid negative feedback to terminate hypothalamic-pituitary-adrenal (HPA) axis activation. Hypothyroidism is associated with a centrally mediated adrenal insufficiency associated. The aim of this study was to examine whether this may be explained by a disturbed glucocorticoid feedback through specific brain receptors: the mineralocorticoid (MR) and glucocorticoid receptor (GR). Methods: Cytosolic receptor binding and gene expression was assessed in male Sprague-Dawley rats (350gm) with short- (7 days) and long-standing (60 days) hypothyroidism (thyroidectomy). Glucocorticoid receptor number and binding affinity in the hippocampus were measured using radioreceptor assay. In situ hybridization was employed to examine GR and MRmRNA levels in the hippocampus and the pituitary. Results: No differences in receptor number or affinity were observed after 7days and 60days treatment. Increased GRmRNA expression in the anterior pituitary was observed in 7day hypothyroid rats under basal conditions compared to euthyroid rats (122.77+4.93 vs 99.65+4.83 DPM/mg; p<0.05), which was associated with significantly decreased GRmRNA levels after osmotic stress (100.82+2.8 vs 110.48+4.1 DPM/mg; p<0.05). No differences were observed at 60days. No effect on MR mRNA expression in the hippocampus was seen in basal condition after both 7- and 60days hypothyroidism. MRmRNA was significantly decreased in 60 days-hypothyroid rats compared to euthyroid after normal saline (3995.67+131.54 vs 5121.00+505.2 DPM/mg; p<0.05). Conclusion: Hypothyroidism resulted in significant changes in GR and MR mRNA levels, in the hippocampus and the pituitary, without changes in receptor number and binding affinity.

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