782 research outputs found

    Key-lock pair mechanism for access control using tribes of Farey fractions.

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    We propose a new single key-lock mechanism based on the concept of an access control matrix. In this system, each file is given a lock and each user is given a key and through simple operations on keys and locks the user access privilege can be revealed. We use Chinese Remainder theorem and tribes of Farey fractions in this method instead of the method based on Euler’s Theorem of Number Theory used by Chang [2]. An advantage of our method is the ease with which coding can be done for the locking mechanism and for the much larger number of users and files

    Discrete quaternion Fourier transform in signal processing systems.

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    We define n th root of unity in quaternion space and then we define discrete quaternion Fourier transform. We use first order quaternion filter for implementing fourth order real co-efficient filter

    Doping Dependence of Thermal Oxidation on n-type 4H-SiC

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    The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range 1000C to 1200C for samples with nitrogen doping in the range of 6.5e15/cm3 to 9.3e18/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in linear rate constant pre-exponential factor from 10-6m/s to 10-2m/s and the parabolic rate constant pre-exponential factor from 10e9m2/s to 10e6m2/s. The increase in linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to degradation in oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6eV to 2.8eV, while the parabolic activation energy varied from 2.7eV to 3.3eV, increasing with doping concentration. These increased activation energies were attributed to higher nitrogen content, leading to an increase in effective bond energy stemming from the difference in C-Si (2.82eV) and Si-N (4.26eV) binding energies. This work provides crucial information in the engineering of SiO2 dielectrics for SiC MOS structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.Comment: 13 pages. 9 figures, accepted as a transiction in IEEE electron device. TED MS#8035

    On Demand Feedback Analysis for Certification Process

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    Many companies provide certifications to other vendors to validate that the vendor’s product functions efficiently on their technology. But it so happens that the process of certification might take longer due to errors that pop up which the vendors will not be able to resolve. The vendors need to resolve the errors with the help of product owner’s engineers which is a lengthy and less efficient process. With this in regard, the solution of on-demand feedback analysis of the certification process proposed in this paper helps minimize the delay in the certification process

    3D Bioprinted Sustained-Release Platform for Intravaginal Delivery of Probiotics

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    • Bacterial Vaginosis (BV) is the most prevalent vaginal infection, affecting 30% of reproductive age women in the United States and worldwide. • BV is characterized by a shift in the vaginal microbiome from a dominance of Lactobacilli to the overgrowth of vaginal pathogens (specifically Gardnerella vaginalis). • Some common complications include adverse pregnancy outcomes and increased risk for sexually transmitted diseases. • Current treatment primarily involves antibiotics, but this is ineffective due to high antibiotic resistance and BV recurrence rates of 50%. Thus, a more permanent cure is sought. • Lactobacilli probiotics are a promising alternative to antibiotics. They have shown success in reestablishing healthy flora, inhibiting pathogen growth, and reducing recurrence. • Probiotics have been administered both orally and intravaginally, but vaginal delivery is preferred. • Unfortunately, present vaginal dosage forms require frequent administration, thereby decreasing user adherence and efficacy. • Only one sustained release probiotic dosage form, in the form of pod intravaginal rings, has been published to date. However this design leads to discomfort and is susceptible to biofilm formation. • Therefore, an intravaginal probiotic delivery platform capable of sustained release and that offers women flexibility in dosage forms is necessary

    Correlation of amniotic fluid index with fetomaternal outcome

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    Background: Amniotic fluid acts like a protective cover around the baby. Advances in ultrasound have increased early detection of abnormal amniotic fluid volumes. Any variation in the amniotic fluid volume warrants antenatal foetal surveillance.Methods: 300 pregnant women between 37 to 40 weeks of gestation were included in the study. A detailed history, examination and ultrasound was done. Pregnant women were divided into 3 groups’ i.e. normal liquor, oligohydramios and polyhydramnios. All the women were closely monitored during labour and puerperium. Follow-up was done till 7 days post-delivery. Maternal and neonatal data were collected.Results: 300 pregnant women were included in the study, out of which 221 had normal amniotic fluid index (AFI), 64 had oligohydramnios and 15 had polyhydramnios. All baseline characteristics were comparable between the groups except body mass index (BMI). Incidence of meconium stained liquor was significantly higher in oligohydramnios compared to normal AFI and polyhydramnios groups (34.4% versus 10.5% versus 13.3%; p=0.0001). Caesarean section rates were significantly higher in polyhydramnios and oligohydramnios compared to normal AFI group (73.3% versus 70.3% versus 19.9%; p=0.0001). Higher cases of low birth weight were recorded in oligohydramnios group compared to normal AFI and polyhydramnios group group (32.8% versus 18.6% versus 13.3%; p=0.011). Neonatal intensive care unit (NICU) admissions were higher in oligohydramnios (35.9%) and polyhydramnios (33.3%) compared to normal AFI group (35.9% versus 33.3% versus 12.7%; p=0.0001).Conclusions: Abnormal liquor volumes are associated with increased caesarean section rates, NICU admissions and neonatal mortality. Careful assessment of pregnant women is imperative for proper counselling and management

    Facile Rapid Synthesis of Polyaniline (PANI) Nanofibers

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    A Polyaniline (PANI) nanofibers have been successfully synthesized by a facile rapid oxidative polymerization of aniline hydrochloride and ammonium persulfate at high temperature (60 C). The structural and optical properties of PANI nanofibers are investigated by using X-ray diffraction (XRD), UV-VIS Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The XRD analysis ascertains formation of PANI with nanocrystalline nature with average crystallite size 30 nm. Further, FTIR pattern confirmed the formation of PANI. SEM analysis has revealed homogeneous fibrous morphology of PANI nanofibers, a well formed mesh of interconnected and entangled PANI nano-fibers over the scanned area. The UV-VIS spectroscopic analysis shows three major absorption peaks at 256.73, 361.17 and 480.95 nm confirmed the PANI formation with conducting state

    Synthesis of Cuprous Oxide (Cu2O) Nanoparticles – a Review

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    Cuprous Oxide (Cu2O) a semiconductor material oxide; with unique optoelectronic properties; gains significant importance for its synthesis in view of its various technological and industrial applications. A few liquid phase methods for the synthesis of Cu2O nanoparticles are reviewed on the basis of materials, methodology, synthesis conditions and key findings. A comparative study of these methods is also performed following criteria of repeatability, safety, cost, time span and simplicity. Contextual to the above mentioned criteria, three liquid phase synthesis techniques were shortlisted and actually experimented (as reported) to synthesize the Cu2O nanoparticles. This was done to investigate the effectiveness, repeatability and stability of the synthesized Cu2O product as a function of ageing time. The synthesized Cu2O using all these techniques are prone to be unstable and undergo the rapid phase change to CuO phase which was ascertained from the shift of absorbance peak in UV-VIS spectra. The results have highlighted the urgent need to develop a facile, economical, scalable and safe method to synthesize stable Cu2O nanoparticles at room temperature

    Digital augmentation for accelerating agroecological intensification with crops, trees and livestock

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