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2022 ◽  
Author(s):  
Samuele Giannini ◽  
Wei-Tao Peng ◽  
Lorenzo Cupellini ◽  
Daniele Padula ◽  
Antoine Carof ◽  
...  

Abstract Designing molecular materials with very large exciton diffusion lengths would remove some of the intrinsic limitations of present-day organic optoelectronic devices. Yet, the nature of excitons in these materials is still not sufficiently well understood. Here we present Frenkel exciton surface hopping, a highly efficient method to propagate excitons through truly nano-scale materials by solving the time-dependent Schrödinger equation coupled to nuclear motion. We find a clear correlation between diffusion constant and quantum delocalization of the exciton. In materials featuring some of the highest diffusion lengths to date, e.g. the non-fullerene acceptor Y6, the exciton propagates via a transient delocalization mechanism, reminiscent to what was recently proposed for charge transport. Yet, the extent of delocalization is rather modest, even in Y6, and found to be limited by the relatively large exciton reorganization energy. On this basis we chart out a path for rationally improving exciton transport in organic optoelectronic materials.


2022 ◽  
Vol 14 (2) ◽  
pp. 714
Author(s):  
Mahdi Mohammed Alamri

Students’ learning environments are significantly influenced by massive open online courses (MOOCs). To better understand how students could implement learning technology for educational purposes, this study creates a structural equation model and tests confirmatory factor analysis. Therefore, the aim of this study was to develop a model through investigating observability (OB), complexity (CO), trialability (TR), and perceived usefulness (PU) with perceived ease-of-use (PEU) of MOOCs adoption by university students to measure their academic self-efficacy (ASE), learning engagement (LE), and learning persistence (LP). As a result, the study used an expanded variant of the innovation diffusion theory (IDT) and the technology acceptance model (TAM) as the research model. Structural Equation Modeling (SEM) with Smart-PLS was applied to quantitative data collection and analysis of 540 university students as respondents. Student responses were grouped into nine factors and evaluated to decide the students’ ASE, LE, and LP. The findings revealed a clear correlation between OB, CO, and TR, all of which were important predictors of PU and PEU. Students’ ASE, LE, and LP were affected by PEU and PU. This study’s established model was effective in explaining students’ ASE, LE, and LP on MOOC adoption. These findings suggest implications for designing and developing effective instructional and learning strategies in MOOCs in terms of learners’ perceptions of themselves, their instructors, and learning support systems.


Author(s):  
Yan Longlong ◽  
Bo Gao ◽  
Dan Ni ◽  
Ning Zhang ◽  
Wenjie Zhou

Abstract To accurately capture the behaviors of cavitation and reveal the unsteady cavitating flow mechanism, a condensate pump inducer is numerically analyzed in a separate numerical experiment with LES at critical cavitation number sind,c under the design point. Based on the new Omega vortex identification method, the correction between the flow structures and cavities is clearly illustrated. Besides, the pressure fluctuations around the inducer are analyzed. Special emphasis is put on the analysis of the interactions between the cavities, turbulent fluctuations, and vortical flow structures. The Omega vortex identification method could give an overall picture of the whole cavitating flow structures to present a clear correlation between the vortices and cavities. The results show that the shear cavitation dominant the cavitation characteristics under the design point. The pure rigid rotation region mainly concentrates at the edge of the cavities while the other sheet-like cavities near the casing walls are characterized by strong turbulence fluctuations. Besides, based on the analysis of the correlation between the cavities and flow structures, the rotating cavitation under the design point may mainly attribute to the interaction between the tip leakage vortex cavitation and the next blade.


2022 ◽  
pp. 002199832110605
Author(s):  
Niels van Hoorn ◽  
Christos Kassapoglou ◽  
Sergio Turteltaub ◽  
Wouter van den Brink

Impact experiments of thick fabric carbon/epoxy laminate specimens, with small thickness ratio, are conducted at distinct energy levels and thicknesses to characterise the damage process. These specimens and loading conditions are representative of a new generation of critical structural components in aviation, such as wing spars, landing gear beams and fittings, that are increasingly being made entirely from composites. The tests address the need to better understand the damage process for specimens with a small thickness ratio since existing experimental impact data for large thickness ratio (thin laminates) may not be directly applicable. Two energy levels, two different fabric layups and two impact methods (drop-weight and gas-cannon) were used. Data from high-speed cameras were processed in a novel way, providing the force during impact. C-scans and micrographs were used to characterise damage. The results show that specimens with a thickness ratio of 5 (20 mm thick) experience more bending compared to specimens with a ratio 2.5 (40 mm thick). For gas-cannon impacts, this results in a higher delaminated area. The drop-weight impacts show almost no differences in damage size for the thickness range analysed. The influence of layup on the global impact response is negligible, but locally it can result in significant variations in dent depth. The dent depth scales linearly with the impact energy and the delaminated area linearly with the impact velocity. There is no clear correlation between the compression-after-impact failure mechanisms and the residual strength. Impact damage, at the current energy levels, showed a minimal reduction of residual strength.


Author(s):  
Namita Agrawal

Abstract: India has applied for GST for their taxation system which has already been applied by more than 160 Nations worldwide. GST has changed India’s perception in front of policy makers of other countries, global investors including big automobile companies. The growth of automobile sector has clear correlation with the policy reforms as it affects domestic demand pattern as well as trade balance. The automobile industry in India is the most booming industry from last many years. India has become the fourth substantial automobile market in 2019 with increasing sales by 8.3% to 3.99 million units. It was the seventh substantial automobile manufacturer in 2018. The government of India has also known the importance of automobile industry. India has imposed a flare of hope by determined growth targets, supported by many of vital undertaking such as Digital India and the make in India campaigns. There are many changes made ensuring simplicity in the GST tax system. The purpose of the study is to understand the impact of these changes by Automobile Manufacturers (OEMs). Keywords: GST, Taxation, Commercial vehicle, automobile manufacturer.


2021 ◽  
pp. 1-9
Author(s):  
Ryszard Tomasiuk ◽  
◽  
Igor Z Zubrzycki ◽  
Magdalena Wiacek ◽  
◽  
...  

The objective of this study was to analyze the dynamics and differences of changes in obesity-defining parameters such as body mass index (BMI), waist circumference (WC), total cholesterol (TC), tricarboxylic acid (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) in representative samples from the US and South Korea in analogous sampling frames comprising the years 2007 - 2008 and 2009 - 2010. Differences in anthropometric parameters and serum lipid levels between specific sampling frames were evaluated using a t-test for unpaired data. Age-dependent changes were analyzed using the GLM technique and the Bonferroni-Dunn post-hock test. Among all subjects, the obesity defined by BMI is cross-correlated with an increase in WC. However, in extremely obese women in the United States, there is a lack of a direct relationship between BMI and WC. There was also a clear correlation between the relative change in WC and serum lipid levels in subjects of different ethnic groups. This study showed that BMI and WC could be interchangeably used to assess the health risks associated with increased serum lipid levels in US and South Korean populations


Author(s):  
J. Christopher D. Terry ◽  
Jacob D. O’Sullivan ◽  
Axel G. Rossberg

AbstractAlthough there is some evidence that larger species could be more prone to population declines, the potential role of size traits in determining changes in community composition has been underexplored in global-scale analyses. Here, we combine a large cross-taxon assemblage time series database (BioTIME) with multiple trait databases to show that there is no clear correlation within communities between size traits and changes in abundance over time, suggesting that there is no consistent tendency for larger species to be doing proportionally better or worse than smaller species at local scales.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261923
Author(s):  
Insani Budiningsih ◽  
Yoes Prijatna Dachlan ◽  
Usman Hadi ◽  
Jaap Michiel Middeldorp

Plasmodium falciparum Malaria and Epstein-Barr Virus (EBV) infection are risk factors in the development of Burkitt’s lymphoma. In Indonesia, 100% of the population is persistently infected with EBV early in life and at risk of developing EBV-linked cancers. Currently, 10.7 million people in Indonesia are living in Malaria-endemic areas. This cross-sectional study was initiated to investigate how acute Malaria dysregulates immune control over latent EBV infection. Using blood and plasma samples of 68 patients with acute Malaria and 27 healthy controls, we measured the level of parasitemia for each plasmodium type (P. falciparum, P. vivax, and mixed) by microscopy and rapid test. The level of 4 regulatory cytokines was determined by quantitative ELISA and the level of circulating EBV genome by real-time PCR targeting the single copy EBNA-1 sequence. All Plasmodium-infected cases had high-level parasitemia (>1000 parasites/ul blood) except for one case. EBV-DNA levels were significantly more elevated in P. falciparum and P. vivax infections (P<0.05) compared to controls. EBV-DNA levels were not related to age, gender, Malaria symptoms, or plasmodium type. TNF-α and IL-10 levels were increased in Malaria cases versus controls, but IFN-γ and TGF- β levels were comparable between the groups. Only TNF-α levels in P. falciparum cases showed a clear correlation with elevated EBV DNA levels (R2 = 0.8915). This is the first study addressing the relation between EBV (re)activation and cytokine responses during acute Malaria, revealing a clear correlation between pro-inflammatory cytokine TNF-α and EBV-DNA levels, specifically in P. falciparum cases, suggesting this cytokine to be key in dysregulating EBV homeostasis during acute P. falciparum Malaria.


Author(s):  
Sheila Garcia ◽  
Rafael Cardoso Harduim ◽  
Fortune Homsanin ◽  
Carlos Renato Zacharias ◽  
Ricardo Machado Kuster ◽  
...  

Background: although Hahnemann described the fifty-milesimal (LM) method in the 6th edition of the Organon of the Medical Art, very little research has been carried out on the physical chemical properties of these homeopathic preparations. Furthermore, there is still no evidence allowing for the correlation between the alleged physical chemical properties and the biological effects of high dilutions. Aims: to evaluate physical chemical characteristics of LM preparations including electrical conductivity, pH and refraction index, and their effect on biological experimental models. Materials and methods: preparations tested for physical chemical analysis were dilutions 1 lm to 10 lm of Euphorbia tirucalli L. prepared from the latex and the juice of the plant. To rule the seasonal characteristics of this plant, 2 different populations were used, one collected in June 2007 and the other in May 2008. Furthermore, the cytotoxic effect of Euphorbia tirucalli 5 lm was tested on human breast cancer cells (MCF7) through MTT assay. Some differences among the two collections were observed. However, any clear correlation could be observed between physical chemical properties and biological activity.


Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Giovanni Landi ◽  
Luca La Notte ◽  
Alessandro Lorenzo Palma ◽  
Andrea Sorrentino ◽  
Maria Grazia Maglione ◽  
...  

Environmentally friendly energy storage devices have been fabricated by using functional materials obtained from completely renewable resources. Gelatin, chitosan, casein, guar gum and carboxymethyl cellulose have been investigated as sustainable and low-cost binders within the electrode active material of water-processable symmetric carbon-based supercapacitors. Such binders are selected from natural-derived materials and industrial by-products to obtain economic and environmental benefits. The electrochemical properties of the devices based on the different binders are compared by using cyclic voltammetry, galvanostatic charge/discharge curves and impedance spectroscopy. The fabricated supercapacitors exhibit series resistance lower than a few ohms and values of the specific capacitance ranged between 30 F/g and 80 F/g. The most performant device can deliver ca. 3.6 Wh/kg of energy at a high power density of 3925 W/kg. Gelatin, casein and carboxymethyl cellulose-based devices have shown device stability up to 1000 cycles. Detailed analysis on the charge storage mechanisms (e.g., involving faradaic and non-faradaic processes) at the electrode/electrolyte interface reveals a pseudocapacitance behavior within the supercapacitors. A clear correlation between the electrochemical performances (e.g., cycle stability, capacitance retention, series resistance value, coulombic efficiency) ageing phenomena and charge storage mechanisms within the porous carbon-based electrode have been discussed.


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