A systematic review on 1,8-naphthalimide derivatives as emissive materials in organic light-emitting diodes

Journal of Materials Science - Organic light-emitting devices (OLEDs) have garnered significant research attention owing to their immense application prospects in leading technologies for...     

Investigation into Effect of Ceramic Fillers on Mechanical and Tribological Properties of Bamboo-Glass Hybrid Fiber Reinforced Polymer Composites

Silicon - Ceramic fillers (TiO2 and ZrO2) having different morphology were used for reinforcement of bamboo-glass hybrid polymer composites. A particular emphasis is focused on special filler...     

Characterization and Antifungal Activity of Pomegranate Peel Extract and its Use in Polysaccharide-Based Edible Coatings to Extend the Shelf-Life of Capsicum (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.)

Effect of pomegranate peel extract (PPE) in two polysaccharide-based edible coatings namely chitosan and alginate on capsicum (Capsicum annuum L.) was studied during storage at 10 °C. The characterization of PPE confirmed the presence of polyphenols such as punicalagin, catechin, and rutin. PPE also demonstrated antifungal activity against the fungal strain of Colletotrichum gloeosporioides. Incorporation of PPE in chitosan coating recorded significant (P?<?0.05) retention of physiological loss in weight, firmness, color, and ascorbic acid in the samples as compared to the control. The restricted losses in total chlorophyll were found to be 22, 29, 38, and 48 in the samples coated with PPE-enriched chitosan, chitosan alone, PPE-enriched alginate, and alginate alone respectively as compared to higher loss of around 71% in control samples during storage. The addition of PPE in these two coatings could also inhibit the microbial growth, maintain sensory scores, and extend the shelf-life up to 25 days at 10 °C.     

Aluminum-induced in situ crystallization of HWCVD a-Si:H films

Aluminum-induced in situ crystallization (AIC) of amorphous silicon films deposited by hot wire chemical vapor deposition (HWCVD) on glass is demonstrated. Aluminum was deposited at temperatures varying from room temperature to 300 °C on HWCVD a-Si:H films. The AIC was observed to take place in situ during the deposition of Al films, when the glass/a-Si:H temperature is kept 300 °C. A 20-nm Al film was effective in inducing crystallization of about 63% in the a-Si:H film. Thus, separate post-deposition annealing step can be avoided. For an Al film thickness comparable to the amorphous silicon film deposited at an optimum deposition rate, crystallization at temperature as low as 200 °C is observed. It was also observed that the growth pattern of c-Si in case of AIC without post-deposition annealing was identical to AIC with annealing step.     

An assessment of the antioxidant potential of coriander extracts in ghee when stored at high temperature and during deep fat frying

A coriander extract was evaluated for its potential to increase oxidative stability of ghee. Antioxidant activity using β‐carotene–linoleic acid model system and radical scavenging activity by 2‐diphenyl‐1‐picrylhydrazyl hydrate free (DPPH) was higher in steam distilled extract compared to its oleoresin counterpart. Steam distilled extract and oleoresin were significantly effective in retarding the deterioration of ghee relative to control, as observed in peroxide value, conjugated dienes, thiobarbituric acid (TBA) value and oxidative stability index at the end of 21 days of storage. However, these were less effective than butylated hydroxyanisole (BHA). During deep fat frying, steam distilled extracts showed higher antioxidant activity compared to oleoresin and BHA.     

Synchrotron-Based X-ray Microtomography Characterization of the Effect of Processing Variables on Porosity Formation in Laser Power-Bed Additive Manufacturing of Ti-6Al-4V

The porosity observed in additively manufactured (AM) parts is a potential concern for components intended to undergo high-cycle fatigue without post-processing to remove such defects. The morphology of pores can help identify their cause: irregularly shaped lack of fusion or key-holing pores can usually be linked to incorrect processing parameters, while spherical pores suggest trapped gas. Synchrotron-based x-ray microtomography was performed on laser powder-bed AM Ti-6Al-4V samples over a range of processing conditions to investigate the effects of processing parameters on porosity. The process mapping technique was used to control melt pool size. Tomography was also performed on the powder to measure porosity within the powder that may transfer to the parts. As observed previously in experiments with electron beam powder-bed fabrication, significant variations in porosity were found as a function of the processing parameters. A clear connection between processing parameters and resulting porosity formation mechanism was observed in that inadequate melt pool overlap resulted in lack-of-fusion pores whereas excess power density produced keyhole pores.     

On Fast and Accurate Detection of Unauthorized Wireless Access Points Using Clock Skews

We explore the use of clock skew of a wireless local area network access point (AP) as its fingerprint to detect unauthorized APs quickly and accurately. The main goal behind using clock skews is to overcome one of the major limitations of existing solutions—the inability to effectively detect Medium Access Control (MAC) address spoofing. We calculate the clock skew of an AP from the IEEE 802.11 Time Synchronization Function (TSF) time stamps sent out in the beacon/probe response frames. We use two different methods for this purpose—one based on linear programming and the other based on least-square fit. We supplement these methods with a heuristic for differentiating original packets from those sent by the fake APs. We collect TSF time stamp data from several APs in three different residential settings. Using our measurement data as well as data obtained from a large conference setting, we find that clock skews remain consistent over time for the same AP but vary significantly across APs. Furthermore, we improve the resolution of received time stamp of the frames and show that with this enhancement, our methodology can find clock skews very quickly, using 50-100 packets in most of the cases. We also discuss and quantify the impact of various external factors including temperature variation, virtualization, clock source selection, and NTP synchronization on clock skews. Our results indicate that the use of clock skews appears to be an efficient and robust method for detecting fake APs in wireless local area networks.