Performance of kenaf fibre reinforced concrete under static and dynamic loadings

Concrete is considered as a brittle material, its enrichment with distributed short kenaf fibres is believed to increase the toughness of matrices. This is achieved by prohibiting the concrete from being cracked and propagated. Kenaf is a natural fibre has typically some benefits such as being renewable, eco-friendly, biodegradable and locally accessible as compared to other types of fibres used for concrete reinforcement. This study was conducted experimentally to investigate the characteristics of kenaf fibre reinforced concrete (KFRC) materials and to determine the performance of kenaf fibre reinforced concrete beams under static and dynamic loadings. The basic concrete materials used in the study are 10 mm aggregate, ordinary portland cement and clean water. Mixing procedures were evaluated to produce KFRC materials with different chopped fibre lengths (10 mm, 15 mm, 20 mm, 25 mm and 30 mm) and fibre volume fractions (0.5%, 1%, 1.5% and 2%). At the preliminary stage, the alkaline treatment test was carried out on the kenaf fibres. Then, the raw materials and concrete properties were investigated by a series of physical and mechanical property tests on fresh and hardened concrete to identify the optimum characteristics of fibre length and content to be used in the concrete mixture. The study also investigated the structural behaviour of KFRC beams, in which the samples were undertaken by monotonic bending load and repeated bending load tests under four points loading system until failure. The load-deformation behaviour of the beams was observed and monitored during testing. Results from the study of alkaline treatment on kenaf fibres found that the best condition was 5% NaOH in three hour emerging time. The study also found that the optimum length of kenaf fibres was 20 mm and the optimum volume fraction yields the value of 1%. From the KFRC beam tests, it was found that the KFRC beams exhibited better performance as compared to normal concrete beams. The best static and dynamic behaviour was observed for the beam using KFRC in tension zone and plain concrete in compression zone, with the ultimate bending load of 5.9% higher than normal concrete beam after the flexural test and 15.6% higher than normal concrete beam after the repeated load test. By observation, the number of crack formation in tension zone increased by 40% and crack spacing was less by 15% as compared to normal concrete beams. The total energy absorption from the load-deflection behaviour of KFRC beams until ultimate failure was 77% higher than normal concrete beams. The relationships between KFRC material and structural performance against fibre lengths and volume fractions have been developed based on the non-linear numerical models and proposed for the analysis and design of KFRC. Conclusively, KFRC material and structure exhibit appreciable tensile, flexural, and impact strength under static and dynamic loadings compared to normal concrete

Towards building a more complex view of the lateral geniculate nucleus: Recent advances in understanding its role

The lateral geniculate nucleus (LGN) has often been treated in the past as a linear filter that adds little to retinal processing of visual inputs. Here we review anatomical, neurophysiological, brain imaging, and modeling studies that have in recent years built up a much more complex view of LGN . These include effects related to nonlinear dendritic processing, cortical feedback, synchrony and oscillations across LGN populations, as well as involvement of LGN in higher level cognitive processing. Although recent studies have provided valuable insights into early visual processing including the role of LGN, a unified model of LGN responses to real-world objects has not yet been developed. In the light of recent data, we suggest that the role of LGN deserves more careful consideration in developing models of high-level visual processing

Discrete-modulation continuous-variable quantum key distribution enhanced by quantum scissors

It is known that quantum scissors, as non-deterministic amplifiers, can enhance the performance of Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) in noisy and long-distance regimes of operation. Here, we extend this result to a {\em non-Gaussian} CV-QKD protocol with discrete modulation. We show that, by using a proper setting, the use of quantum scissors in the receiver of such discrete-modulation CV-QKD protocols would allow us to achieve positive secret key rates at high loss and high excess noise regimes of operation, which would have been otherwise impossible. This also keeps the prospect of running discrete-modulation CV-QKD over CV quantum repeaters alive

A specialized face-processing model inspired by the organization of monkey face patches explains several face-specific phenomena observed in humans

Converging reports indicate that face images are processed through specialized neural networks in the brain –i.e. face patches in monkeys and the fusiform face area (FFA) in humans. These studies were designed to find out how faces are processed in visual system compared to other objects. Yet, the underlying mechanism of face processing is not completely revealed. Here, we show that a hierarchical computational model, inspired by electrophysiological evidence on face processing in primates, is able to generate representational properties similar to those observed in monkey face patches (posterior, middle and anterior patches). Since the most important goal of sensory neuroscience is linking the neural responses with behavioral outputs, we test whether the proposed model, which is designed to account for neural responses in monkey face patches, is also able to predict well-documented behavioral face phenomena observed in humans. We show that the proposed model satisfies several cognitive face effects such as: composite face effect and the idea of canonical face views. Our model provides insights about the underlying computations that transfer visual information from posterior to anterior face patches

Novel design of array multiplier

In this paper a new array multiplier has been proposed, which has lower power consumption than the regular array multipliers. This technique has been applied on two conventional and leapfrog array multipliers. In the formation of 8×8 multiplier all designs proposed in this paper have been implemented using the HSPICE by the use of 180 nm TSMC technology at a supply voltage 1v. To verify the performance of the proposed structures, structures have been simulated in 130 nm & 65 nm PTM technologies. The simulation results show that applying the return technique in the array structures causes power consumption reduction and consequently PDP reduction. This improvement for 180 nm technology in the conventional array structure is 13.32 % and in the leapfrog array structure is 23.27 %. It should be noted that this technique substantially makes the number of transistors less and as a result area reduction

Prevalence of group B streptococcus colonization in Iranian pregnant women: A systematic review and meta-analysis

Background: Group B Streptococcus (GBS) is an important pathogen in newborns and pregnant women. Objective: The present study was carried out to estimate the prevalence of GBS colonization in pregnant women in Iran. Materials and Methods: This systematic review and meta-analysis was based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis guideline using the national databases including Society for Information Display, Magiran, Irandoc,Iran Medex, and international databases including MEDLINE, Web of Science, Scopus,PubMed, Science-Direct, Cochrane, Embase, Elton Bryson Stephens Company, Centre for Evidence-Based Medicine, Cumulative Index to Nursing and Allied Health Literature, and Google Scholar, published by 01/30/2017. The I2 index was used to measureheterogeneity between the studies. Results: In a total of 667 documents, 30 (4.49%) were selected. In this study, the prevalence of GBS colonization in 10090 Iranian pregnant women was calculated as 13.65% [confidence interval (CI): 95%: 10.56–17.45]. Based on geographic region,24.63% [CI: 95%: 11.52–45.06] in the West and 8.75% [CI: 95%: 6.43–11.8] in the East were the highest and lowest areas in Iran, respectively, and were statistically significant (p = 0.001). Also, with regards to swapping sampling area, Vaginal with 11.96%, Vaginal and Rectal with 13.62%, and Anal and Vaginal with 25.63% were the least to the greatest, respectively, and were statistically significant (p = 0.001). Conclusion: Therefore, based on the recommendation of Centers for Disease Control and Prevention as reported by the Ministry of Health and Medical education, early diagnosis, and screening of high-risk women should be done at 35–37 weeks of pregnancy. Key words: Streptococcus agalactiae, Iran, Pregnancy, Prevalence, Female

Methicillin-Resistant Staphylococcus epidermidis in Iran: A Systematic Review and Meta-Analysis

Objective: Methicillin-resistant Staphylococcus epidermidis (MRSE) remains one of the most prevalent drug-resistant bacteria causing health care infections. Limited data are available about how the frequency of MRSE changed in Iran over the past years. The current study aimed at determining the frequency of MRSE in different cities of Iran. Methods: Databases including Web of Sciences, Scopus, Embase, Medline, and Iranian databases were searched to find studies addressing the frequency of MRSE in Iran published from Mar 2006 to Jan 2016. The data were analyzed using comprehensive meta-analysis version 2.2 (Biostat). Of the 139 records identified in the databases, 15 studies met the inclusion criteria. Results: The analyses showed that the frequency of MRSE infections was 73.9% [95% confidence interval (95% CI) 61.4 - 83.4] among culture-positive cases of S. epidermidis in different parts of Iran. The frequency of MRSE was higher in the studies conducted from 2011 to 2015, based on further stratified analyses. Conclusions: The regular surveillance on antimicrobial susceptibility pattern and formulation of definite antibiotic policy may control high rate of MRSE associated infections in Iran. Moreover, rapid and reliable diagnosis of MRSE isolates and regular screening of the personnel and surfaces of hospitals in terms of MRSE are indispensable