In recent years, near infrared (NIR) spectroscopy has been investigated as a tool for monitoring anaerobic digesters, but several adversities in its application have been reported. This study proposes the application of NIR for the determination of alcohols and volatile organic acids from H2 production bioreactors and evaluates different approaches to optimize the prediction models. Partial least squad (PLS) models were developed using samples from anaerobic batch reactors fed with crude glycerol for wastewater treatment. The analytes predicted were: methanol, ethanol, 1-butanol, acetic, propanoic, butyric, isocaproic and total volatile organic acids (VFA). The optimization of the predictive capacity of the models was achieved through the orthogonal signal correction (OSC) preprocessing and the selection of variables performed by the genetic algorithm (GA). The application of the proposed models were based on the following figures of merit: accuracy, precision, linearity, limits of detection and quantitation, measurement interval, sensitivity, selectivity, signal-to-noise ratio and bias. Despite the low selectivity (maximum of 0.12%), the models presented high sensitivity [γ?1 = 0.19 (mg L?1)?1], low LOQ (1 mg L?1) and correlation between reference and predicted values (r) at least 0.93, except for propanoic acid (rpred = 0.85). The F-test revealed that the selection of variables by GA significantly improved the accuracy and linearity of the prediction models for methanol, acetic acid, isocaproic acid and VFA. NIR spectroscopy has proved to be a powerful tool for monitoring H2 production bioreactors since provides fast, low cost and multicomponent information. 相似文献
This article presents the design of a novel astroid shaped dielectric resonator antenna (DRA) constructed from PTFE Teflon material with a dielectric constant of εr = 2.1 and a loss tangent tan δ = 0.0002 on an FR4 grounded substrate for LTE and ISM band applications. Inverted Omega ?-shaped feed along with asymmetric E-shaped dual metallic strips in the partial ground is used to obtain dual-band characteristics. A light weight, cost-effective plastic material is used to design the antenna. An isolation of 26.5 dB and 24.6 dB is achieved in the two frequency bands 1.8 GHz and 2.4 GHz respectively by modifying the ground plane. Metallic strips and stubs in the ground are used to enhance the isolation in the proposed MIMO system. The obtained impedance bandwidths in both the bands are 14.5% and 13%. The performance of the MIMO system is characterized by the envelope correlation coefficient and diversity gain. Good agreement is found between simulated and measured results. 相似文献
Wireless Personal Communications - An antenna which is used for multipurpose like WiMAX, RADAR altimeter and X-band applications proposed. A tri-band multiple-input–multiple-output antenna... 相似文献
Little is known about vertical transmission of hepatitis E virus from infected mothers to their infants. We studied eight babies born to mothers infected with hepatitis E in third trimester. One baby was icteric at birth with elevated transaminases and four babies had anicteric hepatitis. Two babies were born with hypothermia and hypoglycaemia and died within 24 h; one had massive hepatic necrosis. Hepatitis E virus RNA was detected by PCR in cord or birth blood samples of five infants. Six infants had evidence of hepatitis E infection. We conclude that hepatitis E virus is commonly transmitted from infected mothers to their babies with significant perinatal morbidity and mortality. 相似文献
Communication fields are growing rapidly in the recent era, so transmitting the multimedia contents through an open channel becomes a challenging task. The multimedia contents that are transmitted through this channel are highly prone to vulnerabilities and attacks. Therefore, secure and efficient data communication is considered as a major concern in the multimedia communication systems. So, major efforts are taken by researchers to safeguard the originality of each image. In a conventional system, the secure image communication process was achieved by compressing the content first, and then encryption is performed over the compressed data. Even though it met the required security and compression ratio, but some applications may require the reverse system. In this method, the encryption process is conducted prior to compression to improve the privacy of user data. Moreover, the initial concentration is given for improving content privacy rather than concentrating on size reduction. This paper proposes a reversed system that uses block based perceptual encryption algorithm for encryption and vector quantization (VQ) with hybrid Lloyd–Buzo–Gray (LBG)-Adaptive Deer Hunting Optimization (ADHO) algorithm (VQ-LBG-ADHO) for compression. So, the content secrecy gets improved. The involvement of this adaptive optimization method enhances the performance of VQ in the compression process. This method highly concentrates on secure communication, so the reverse process is followed in this method. It not only improves the image secrecy, however, it further enhances the image quality. The performance of this secure communication process is compared with state-of-the-art algorithms, and the results reveal that the proposed method outperforms the other existing methods.
The design of novel compact two-element and eight-element lotus shaped multiple-input-multiple-output (MIMO) antenna system employing pattern diversity with enhanced isolation characteristics is presented. The proposed two-element antenna system is arranged rotationally on a square-hollow substrate resulting in an eight-element MIMO antenna system employing pattern diversity. The developed eight-element MIMO antenna system resonates in the frequency range 3.1 to 14.6 GHz housing the complete UWB band with triple band-notch characteristics at 3.7–4.5 GHz (C-band satellite down link [3.7–4.2 GHz]), 5.1–5.9 GHz (WLAN) and 6.8–8.25 GHz (X-band satellite down link (7.25–7.75 GHz) and up link (7.9–8.4 GHz)) bands. The antenna system gives element-to-element isolation of more than 25 dB in the majority of the operating band with a peak gain of 6.8 dBi and a maximum 90% efficiency. The important MIMO metrics like ECC (envelope correlation coefficient), DG (diversity gain), total active reflection coefficient (TARC), channel capacity losses (CCL) and MEG (mean effective gain) are presented for both two-element and eight-element to estimate the performance the proposed antennas in multi-antenna environments. The both two- and eight-element designs are fabricated and the measured results of those are well agreed with simulation results. 相似文献