Stanford Stratified Structure Solver (S4) Simulation Tool

The Stanford Stratified Structure Solver (S4) developed in 2012 allows for fast, accurate prediction of optical propagation through complex 3D structures. However, there have been two key challenges preventing wider use to date: the use of a specialized control language, and the difficulty of incorporating realistic materials parameters. In this project, both concerns have been addressed. We have constructed a graphical user interface as an alternative, using the open-source Rappture platform on nanoHUB. This has been combined with a comprehensive materials database known as PhotonicsDB, which incorporates materials optical data drawn from carefully vetted sources. An Octave script file was written to accept the user inputs and then generate and run an S4 control file. The results are then interpreted and displayed on the interface by the xml file. This new S4 GUI was then used to investigate and optimize selective solar thermal absorber designs, which can convert sunlight into heat for direct use in hot water, or for powering mechanical engines. Preliminary results are also presented

Economic Impact of the Western Africa Ebola Outbreak--A Holistic Approach

The 2014 Western Africa Ebola Epidemic was one of the most severe epidemics in the region’s history, creating considerable health and economic burdens on the affected countries. The first part of this paper relies on several macroeconomic databases from 2009 to 2019 to evaluate the aggregate economic impact of Ebola both in the short- and medium-run. We also use household surveys to assess the microeconomic effects of Ebola on employment and household non-farm enterprises (HNFE) at different phases of the outbreak in Sierra Leone. Our primary estimation method is the Difference-in-Differences approach with the canonical specification where we compare outcome variables between Ebola affected and non-affected countries. To address the recently raised concerns about the Difference-in-Difference approach with multiple periods, we apply the nonparametric approach proposed by Callaway and Sant’Anna (2020) and calculate the summary measures proposed by de Chaisemartin & D\u27Haultfoeuille (2020) as robustness checks. We find a significantly negative effect of Ebola on Foreign Direct Investment inflows in the short-run and a persistently negative effect on iron exports during the sample periods but no noticeable impact on GDP and inflation rate. Ebola also decreased the probability of being employed at an early stage and continuously depresses the HNFE’s revenue toward the end of the epidemic. Our results suggest that the Ebola outbreak should be considered as a nationwide economic shock with limited long-run macro effect

Cloning and analysis of plant fatty acid desaturase 7 gene promoter from Brassica napus

In order to investigate the regulation mode of Brassica napus FAD7 gene in response of thermal stress, we measured the protein levels of BnFAD7 in plant at low and high temperature, and then analyzed promoter activity of 5’-flanking regions of BnFAD7 by transient gene expression in B. napus protoplasts at different temperatures. Our studies indicated that no significant change occurred in the expression level of BnFAD7 both at high and low temperature, while BnFAD7 promoter showed a heat-induced regulation mode and slowly increased activity at the chilling conditions, which suggested there are heat-induced cis-action element lies in BnFAD7 promoter sequence. Our data also suggested that a post-transcription regulation pattern existed to ensure BnFAD7 function in the acclimation to temperature stress. Furthermore, our studies give new evidence for the hypothesis that BnFAD7 and BnFAD8 gene may come from the same ancestor gene.Keywords: Brassica napus, fatty acids desaturase, promoter analysis, transient expression, BnFAD

Influence of Fe 3

The magnetic electrospinning (MES) method has been applied to generate aligned nanofibers. But researchers have different viewpoints on the usage of magnetic particles in the polymeric solutions. In order to investigate the effect of magnetic particles in forming the ordered fibers, the poly(lactic-co-glycolic acid) solutions with or without Fe3O4 nanoparticles were electrospun via MES. The fibers were compared at different voltages (13.5, 15.5, 17.5, and 19.5 kV) and flow rates (0.6, 0.9, 1.2, and 1.8 mL/h). It is shown that the well-aligned fibers can be fabricated by both magnetic and nonmagnetic solutions. The doping of Fe3O4 nanoparticles can increase the aligned fibers in some degree, especially at high applied voltage and flow rate. The diameters of fibers electrospun by MES were smaller than those by conventional electrospinning, and the diameter of fibers by MES without magnet particles was the smallest

A conceptional approach of resin-transfer-molding to rosin-sourced epoxy matrix green composites†

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites