A review of stimuli-responsive shape memory polymer composites

This paper aims to compare the material removal rate, ν between a Dimensional Analysis (DA) model, an Artificial Neural Network (ANN) model and an experimental result for a low gap current of an Electrical Discharge Machining (EDM) process. The data analysis is based on a copper electrode and steel workpiece materials. The DA and ANN model that have been developed and reported earlier by authors are used to compare the material removal of EDM process. The result indicated that the ANN model provides better accuracy towards the experimental results.

Comparison Studies of Electrical Discharge Machining (EDM) Process Model for Low Gap Current

Underwater communication remains a challenging technology via communication cables and the cost of underwater sensor network (UWSN) deployment is still very high. As an alternative, underwater wireless communication has been proposed and have received more attention in the last decade. Preliminary research indicated that the Radio Frequency (RF) and Magneto-Inductive (MI) communication achieve higher data rate in the near field communication. The optical communication achieves good performance when limited to the line-of-sight positioning. The acoustic communication allows long transmission range. However, it suffers from transmission losses and time-varying signal distortion due to its dependency on environmental properties. These latter are salinity, temperature, pressure, depth of transceivers, and the environment geometry. This paper is focused on both the acoustic and magneto-inductive communications, which are the most used technologies for underwater networking. Such as acoustic communication is employed for applications requiring long communication range while the MI is used for real-time communication. Moreover, this paper highlights the trade-off between underwater properties, wireless communication technologies, and communication quality. This can help the researcher community by providing clear insight for further research.

Underwater Wireless Sensor Networks: A Survey on Enabling Technologies, Localization Protocols, and Internet of Underwater Things

The food traceability regulations of 21 Organization for Economic Co-Operation and Development (OECD) countries were examined with attention to whether these regulations are comprehensive for all food commodities and processed foods. The countries were evaluated based on responses to a series of questions that were developed to allow assessment of their traceability programs. The questions sought background information on whether: mandatory traceability regulation(s) exists at the national level within a given country; regulations include imported products, and the nature of required documentation for imports; an electronic database(s) for traceability exists and, if present, its accessibility; and labeling regulations allow consumer access and understanding of traceability. The examination ranked the countries that have specific traceability regulations for all commodities, both domestic and imports, as "Progressive," while countries with less broad or stringent regulations were ranked as "Moderate," and countries that were still in the developmental stage of mandatory or industry-led traceability requirements were ranked as "Regressive." Aggregate scores were developed from all of the rankings, determined on the basis of the questions, for each of the 21 countries, to provide an overall world ranking score. The aggregate scores were "Superior," "Average," or "Poor."

/pdf/comparison-of-global-food-traceability-regulations-and-3k6jd06zwr.pdf

Comparison of Global Food Traceability Regulations and Requirements

A review on the fatigue behavior of Ti-6Al-4V fabricated by electron beam melting additive manufacturing

This paper is a brief review of Rain AttenuationModelling and Mitigation in the Tropics. The fast depleting availability of the lower frequency bands like the Ku-band as a result of congestion by commercial satellite operations coupled with severe rain attenuations experienced at higher frequency bands (Ka and Q/V), particularly in the tropical regions which was caused by higher rainfall rates and bigger raindrop size, amongst others; it was pertinent that deliberate effforts be geared towards research along this direction. This became even more critical owing to a dearth database along the slant path in the tropical regions for use in rain propagation studies at microwave frequencies, especially at millimeter wave bands (where most signal depolarization and fading takes place). The results presented in this work are valuable for design and planning of the satellite link, particularly in the tropical regions.DAH, ITU-R and SAM model simulations along the slant-path were investigated using local rainfall data at 0.01% of the time, while making use of TRMM data from NigComSat-1 satellite to obtain the measured data for Lagos. Terrestrial attenuation data for 0.01% of the time for UTM were obtained from the UTM wireless communication center (WCC). The attenuation data were thereafter transformed to slant path using transformation technique proposed for Ku band byA. Y. Abdulrahman. Theattenuation exceeded for other percentages of the average year was obtained using statistical interpolation extrapolation method.It was observed that the proposed model predicts creditably well for the ka down link frequency band, by producing the best performance when compared with SAM, DAH and ITU-R models. DOI: http://dx.doi.org/10.11591/ijece.v2i6.1222

/pdf/rain-attenuation-modelling-and-mitigation-in-the-tropics-4gg7byeltm.pdf

Rain Attenuation Modelling and Mitigation in The Tropics: Brief Review

This paper presents a calculation of the dielectric properties of low-loss materials using the transmission phase-shift method. This method can provide calibration-independent and position-insensitive features, and it was verified experimentally by measuring several well-known samples using X-band rectangular waveguides.

Dielectric measurements for low-loss materials using transmission phase-shift method

In the underwater communication and target locating, the biggest challenge is to reduce the effect of underwater acoustic noise (UWAN). An experimental model is presented in this paper to characterize noise in the acoustic underwater channel in shallow water. Data is measured from different depths located in the Tanjung Balau, Johor, Malaysia. Most applications assume the UWAN as additive and Gaussian. However, the UWAN is not just thermal noise but a combination of turbulence, shipping and wind noises. Site-specific noise in shallow water often contains significant non-Gaussian components. Thus, it is appropriate to assume UWAN as colored rather than white with non-Gaussian probability density function (pdf). The real-time noise data are analyzed for different depths to determine the statistical properties such as power spectral density (PSD), autocorrelation function and pdf. The results show the UWAN has a non-Gaussian pdf, and is colored with a power spectral density that decays at a rate of approximately 20 dB/decade. Also, the power decreases with increasing depth as the distance from the surface at approximately 10 dB.

Underwater Acoustic Noise Characteristics of Shallow Water in Tropical Seas

Acoustic underwater sensor network (UWSN) is important in terms of business and for military applications. Optimum UWSN design provides a reliable connection with maximum connectivity, minimal multipath, low technical cost, and emphasis on energy conservation. This paper examines the channel estimation parameters, such as channel impulse response, coherence bandwidth, BER due to delay for differentially detected MSK receiver, and transmission loss impact of underwater node placement in three scenarios (ground-based, buoys-based, and horizontal point-to-point sensor node). All data (bathymetry, altimetry, temperature, salinity, and depth) are real and have been sourced from different satellite databases. The case study of this paper is the Desaru beach in the eastern shore of Johor Bahru in Malaysia. In this investigation, Acoustics Toolbox of BELLHOP through MATLAB and mathematical analyzing method has been utilized. As a result, this paper indicates the maximum received power, and the lowest delay time characteristics and TL belong to horizontal point-to-point scenario; moreover, the ground-based scenario has the highest delay time and maximum coherence bandwidth among three scenarios.

Nor Hisham Haji Khamis

Papers

Comparison Studies of Electrical Discharge Machining (EDM) Process Model for Low Gap Current

Rain Attenuation Modelling and Mitigation in The Tropics: Brief Review

Dielectric measurements for low-loss materials using transmission phase-shift method

Underwater Acoustic Noise Characteristics of Shallow Water in Tropical Seas

Study of Underwater Channel Estimation Based on Different Node Placement in Shallow Water