Search

Abstract

Abstract

Dye-sensitized solar cells (DSCs) have attracted incredible attention in recent years as relatively inexpensive alternative to silicon solar cells. Conventionally, a transparent fluoride-doped tin oxide (FTO) conductive glass with a thin layer coating of platinum (Pt) is used as counter electrode in DSCs. The widespread use of Pt as counter electrode in DSCs is due to its catalytic capability for I3-reduction in electrolyte. However, Pt is costly and can be affected by the corrosive nature of I-/I3-redox couple, which makes it a less desirable candidate for use in industrial scale manufacturing. In this study, carbon nanofibers with surface-attached Pt nanoparticles were prepared by stabilization and carbonization of electrospun polyacrylonitrile (PAN) nanofibers and subsequent controllable Pt nanoparticle growth on the obtained carbon nanofiber surface through redox reaction. The hierarchical carbon nanofibers with surface-attached Pt nanoparticles (ECNFs-PtNPs) were then employed as cost-effective counter electrode in DSCs. The effects of size, morphology, and loading of Pt nanoparticles on performance of DSCs were investigated. Compared to conventional counter electrode, the counter electrode that was made of ECNFs-PtNPs exhibited larger open circuit voltage (Voc). The DSCs that were made with ECNFs-PtNPs counter electrode demonstrated excellent solar energy conversion efficiencies in the range of 7% to 8%.

This study examines the proximate determinants of velocity of money in post-reform China. The study confirms that China is still in the first phase (declining) of U-shaped velocity behavior witnessed in other industrialized countries. The empirical results also show that the decline in M2 velocity is more pronounced than that of M1 velocity, and that the long-run determinants of velocity are primarily influenced by transactions demand for money and to a lesser extent by alternative cost of holding money. Finally, the study brings into the focus of the increasing role of financial innovation in explaining velocity behavior of monetary aggregates in China.

AbstractThis study examines the proximate determinants of velocity of money in post-reform China. The study confirms that China is still in the first phase (declining) of U-shaped velocity behavior witnessed in other industrialized countries. The empirical results also show that the decline in M2 velocity is more pronounced than that of M1 velocity, and that the long-run determinants of velocity are primarily influenced by transactions demand for money and to a lesser extent by alternative cost of holding money. Finally, the study brings into the focus of the increasing role of financial innovation in explaining velocity behavior of monetary aggregates in China.

Failure by delamination of composite laminates due to low velocity impact damages is critical because of the subsurface nature of delamination. Traditional methods such as stitching and Zpinning, while improving interlaminar properties in woven composites, lead to a reduction of the inplane properties. To alleviate these problems, use of Tetra Ethyl Orthosilicate (TEOS) nano fibers manufactured using electrospinning technique in fiber Glass-Epon composite laminates is investigated for their potential to improve the interlaminar properties. Electrospun coated fiber glass woven mats are impregnated with epoxy resin using Heated-Vaccum Assisted Resin Transfer Moulding (H-VARTM) process. The interlaminar properties of the nano engineered hybrid composites obtained using ASTM Double Cantilever Beam (DCB) tests and short beam shear tests are compared with those without the presence of electrospun fiber layers, to study their influence. The short beam shear tests revealed a 20% improvement due to presence of TEOS interlaminar electrospun nanofibers. It is also noteworthy that fibers cured at different temperature levels had variation in performance as observed in MSBS test results.

Measurement of the tensile properties of high strength woven and knit fabrics, including geotextiles and geogrids traditionally make use of roller grip-type clamping systems. These grips are designed to allow a sample to be pulled in tension without applying an excessive crimping or compressive force on the specimen, thus avoiding premature failure. Roller grips, also known as capstan grips, also have the advantage of allowing the specimen to align itself with the applied force therefore loading the specimen uniformly across the width. However, since the specimen tightens itself around the grip during testing, crosshead travel cannot be used to measure specimen strain, which makes the determination of low strain properties and the selection of modulus values difficult. Two issues that must be addressed in obtaining low strain properties are how to measure sample strain and how to get an accurate and repeatable starting point for the test. This paper will explore alternate methods of gripping systems, strain measurement and data analysis with the objective of accurately measuring and reporting low strain properties of woven and knit textiles.

Polymeric hybrid nanocomposites, due to improved mechanical, thermal, and electrical properties, are key factors in recent technologies. Because of anisotropic characteristics of polymeric hybrid nanocomposites, mechanical properties and their behavior are very difficult to predict. If they are fabricated with complicated woven fabric patterns, it becomes more difficult to predict. This review discusses in detail the properties and manufacturing methods of various fibers, focuses on different manufacturing, processing, and characterization techniques used for polymeric hybrid nanocomposites. Theoretical composite models and some recent advances in modeling and simulation techniques for polymer nanoparticle composites are discussed and thus this review can provide significant guidelines for the development of manufacturing, characterization, testing, modeling, and simulation techniques for high performance hybrid polymer nanocomposites as current state of art.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.