Analysis of signal propagation in an experiment room with epoxy covered floor for wireless sensor network applications

As sensor applications combined with wireless network becoming more of an everyday applications, the optimal deployment becomes ever increasing important as that would be a key important factor in the trade-off between cost and link quality. This paper reports on the effect of epoxy covered floor on signal propagation characteristics in an experiment room. Microchip developed motes were used to measure signal propagation in an experiment room where sensors would be deployed extensively. The results show that the signal strength for 30 cm antenna height provides a significant margin with respect to signal noise floor. As for the 5 cm antenna height, there is still around 25 dB margin in average before the signal reaches noise floor. Analysis shows that the log-distance model is the best fit to the measured data. Free Space Loss model seemed to under estimate the overall performance of the signals. An important conclusion from this study is that wireless mote deployment must consider the margin between the two signals of antenna heights and the margin to noise floor to avoid link quality deterioration especially for sensitive data acquisition applications

Effect of ZSM-5 acidity in enhancement of methanol-to-olefins process

The skyrocketing demand for olefins especially propylene, have necessitated continuous efforts in finding alternate route for olefins production. Hence, methanol to olefins (MTO) was recognized as a feasible process since methanol could simply be mass produced from any gasifiable carbon-based feedstock, such as natural gas, coal, and biomass. Essentially, obtaining a more stable catalyst would improve economy of the MTO process. Acidity of catalyst has major influence in MTO, thus it is an indispensable parameter for conversion of methanol into value-added products. The present paper discusses the reactions involved in MTO process and the effect of acidity in enhancement of light olefin selectivity and catalytic stability. The paper also captured perspectives of crucial research and future direction for catalysts development and technologies that can potentiallly boost olefin production and make it competitive with the conventional olefin production processes

Shape selective alkylation of benzene with methanol over different zeolite catalysts

Benzene methylation is an important process for removing excess benzene in petrochemical industries to produce value-added products such as toluene and xylene. In this study, the performance of three types of zeolites, which is ZSM-5 (HZ), zeolite Y (HY) and zeolite β (Hβ) were investigated as catalyst in the benzene methylation reaction. The catalysts were characterized by N2 adsorption-desorption and FTIR. The N2 adsorption-desorption verified that the mesopores volume of the catalysts was in the following order: HB > HY > HZ. While, the FTIR-lutidine revealed that the HB possessed the highest amount of Brönsted acid sites followed by HZ and HY. The catalytic testing at 573 K showed that HZ gave good performance in benzene methylation with 55.2% and 22.1% yield of toluene and xylene, respectively. It is suggested that HZ catalyst with moderate amount of Brönsted acid sites and smallest mesopores volume appear to be effective for shape selective synthesis of toluene and xylene. In addition, pore structure of HZ also contributed to the high catalytic activity of benzene methylation

A contemporary assessment on composite titania onto graphitic carbon nitride-based catalyst as photocatalyst

Titanium dioxide (TiO2) has drawn widespread interest by researchers as a precious semiconductor that is responsive towards photodegradation of various pollutants. This catalyst has its own limitations such as fast electron-hole recombination, wide band gap, and can only be utilised under ultraviolet (UV) region. In order to overcome these problems, the addition of a metal-free dopant is a common practice to prevent electron-hole recombination and enhance photodegradation under visible light. Among various types of metal-free catalysts, carbon nitride material has received much attention due to its numerous benefits such as good in terms of physical and chemical strength, as well as an attractive electronic band combined with a band gap (2.7 eV). This review summarised recent works in the development of titania incorporated with graphitic carbon nitride (g-C3N4) for enhanced photocatalytic activity

Toluene side chain alkylation with methanol over silica catalyst

MSN and SiO2 catalyst were investigated on side chain toluene alkylation with methanol reaction. Characterization of the catalyst were carried out by XRD, N2 physisorption analysis, FTIR spectroscopy. A pyrrole adsorption FTIR study reveals shifting of perturbed NH stretching increasing slightly in MSN compared to SiO2 catalyst revealed that MSN possessed higher basic sites than SiO2. N2 adsorption desorption isotherm analysis showed that MSN possessed higher surface area than SiO2 as well as increased the amount of mesopores in catalyst. The catalytic side chain toluene alkylation with methanol reaction was conducted in the range of 523K-673K under atmospheric pressure. MSN exhibits the highest catalytic performance compared to SiO2 catalyst

Performance study on the effect of filter curve in CWDM System for the access network

This paper presents the study on the effect of filter variation on the coarse wavelength division multiplexing (CWDM) system. The filter curve will affect the performance of the CWDM system due to changes of received power lever and isolation of the signal. The significant impact on the received power level and isolation can be found when the required signal is isolated from unwanted signal by the steep curve of filter. As a result, BER of 1.0x 10-12 was obtained corresponding to receive power level of -24.27 dBm with isolation of 23.22 dB. When the wavelength spacing is reduced to 1nm, the isolation is only 11.30 dB and BER increased to 5.49x10-7 with a received power of -15.39 dBm

Life cycle assessment (LCA) of particleboard: investigation of the environmental parameters

Particleboard is not entirely a wood replacement but a particular material with its properties, making it more effective at different times than heavy or solid wood. The world's biggest concern is environmental problems with formaldehyde as a particulate board binder that can lead to human carcinogenic agents. A cradle-to-gate life cycle assessment (LCA) of particleboard production was performed using openLCA software. The impact assessment was carried out according to the software's features. This preliminary investigation aims to analyze the chemical composition of particleboard and identify its environmental impact. The Fourier-transform infrared spectroscopy (FTIR) system was used to track the functional group of aliphatic hydrocarbons, inorganic phosphates, and main aliphatic alcohols found in particleboards made in Malaysia. Based on the FTIR results, aliphatic groups were found in numerous aggravates that the spectroscopic infrared was likely to experience. The most important vibrational modes were C-H, at approximately 3000 cm(-1), and -CH deformations around 1460 cm(-1) and 1380 cm(-1). Eight effect groups demonstrated that 100% of the input and all analyses produced the same relative outcome. The life cycle of a product is determined by pollution of the air, water, and soil. Thus, particleboard has a minimal impact on the environment, except for global warming

Exact tail asymptotics in bivariate scale mixture models

Let (X, Y) = (RU 1, RU 2) be a given bivariate scale mixture random vector, with R > 0 independent of the bivariate random vector (U 1, U 2). In this paper we derive exact asymptotic expansions of the joint survivor probability of (X, Y) assuming that R has distribution function in the Gumbel max-domain of attraction, and (U 1, U 2) has a specific local asymptotic behaviour around some absorbing point. We apply our results to investigate the asymptotic behaviour of joint conditional excess distribution and the asymptotic independence for two models of bivariate scale mixture distribution

Performance study on the effect of filter curve in CWDM System for the access network

This paper presents the study on the effect of filter variation on the coarse wavelength division multiplexing (CWDM) system. The filter curve will affect the performance of the CWDM system due to changes of received power lever and isolation of the signal. The significant impact on the received power level and isolation can be found when the required signal is isolated from unwanted signal by the steep curve of filter. As a result, BER of 1.0x 10-12 was obtained corresponding to receive power level of -24.27 dBm with isolation of 23.22 dB. When the wavelength spacing is reduced to 1nm, the isolation is only 11.30 dB and BER increased to 5.49x10-7 with a received power of -15.39 dBm

Performance study on the effect of filter curve in CWDM System for the access network

This paper presents the study on the effect of filter variation on the coarse wavelength division multiplexing (CWDM) system. The filter curve will affect the performance of the CWDM system due to changes of received power lever and isolation of the signal. The significant impact on the received power level and isolation can be found when the required signal is isolated from unwanted signal by the steep curve of filter. As a result, BER of 1.0x 10-12 was obtained corresponding to receive power level of -24.27 dBm with isolation of 23.22 dB. When the wavelength spacing is reduced to 1nm, the isolation is only 11.30 dB and BER increased to 5.49x10-7 with a received power of -15.39 dBm