Digestate residues analysis under elevated heat regime by using DNS method

Hanif, Mohamad Haziq,Kamaruddin, Mohamad Anuar,Norashiddin, Faris Aiman,Zawawi, Mohd Hafiz Techno-Press 2020 Advances in environmental research Vol.9 No.1

The problems with unsorted municipal waste are always associated with disposal issues as it requires a large area for landfilling or high energy used for incineration. In recent years, an autoclaving technique has been considered a promising approach which could minimize the volume of organic waste from being directly disposed or incinerated. In this work, an attempt was done to study the saccharification potential of organic residues under elevated temperature Thermal treatment involving hot water bath was applied to treat the organic residue ranging from 60℃ to 100℃ for 30 and 60 minutes. The result obtained showed an increasing trend for the concentration of glucose and carbohydrate. However, the result for lignocellulose content which contains various component includes extractive, holocellulose, hemicellulose, cellulose and lignin show variation. Based on the thermal treatment carried out, the result indicated that the trend of glucose and carbohydrate content. The highest percentage of glucose that can be obtained 978.602 ㎍/ml which could be obtained at 90℃ at 60 minutes. The carbohydrate also shows an increasing trend with 0.234 mg/ml as the highest peak achieved at 80℃ for 30 minutes treatment. However, it was found that the lignocellulose content varies with temperature and time. The statistical analysis was carried out using two-ways ANOVA shows an interaction effect between the independent variables (temperature and contact time) and the saccharification effects on the food wastes. The result shows a variation in the significant effect of independent variables on the changes in the composition of food waste.

Insight into hydrophobic interactions between methyl ester sulfonate (MES) and polyacrylamide in alkaline-surfactant-polymer (ASP) flooding

Saiful Hafiz Habib,Dina Kania,Robiah Yunus,Badrul Hisham Mohamad Jan,Dayang Radiah Awang Biak,Rabitah Zakaria 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.11

The interaction between methyl ester sulfonate (MES) surfactant and polyacrylamide (PAM) polymer in alkaline-surfactant-polymer (ASP) flooding due to electrostatic charges and hydrophobicity of both elements at the interface was investigated. In the ASP flooding, sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) were used as alkali. At high PAM concentrations, the strong hydrophobic interaction between the PAM backbone and the carbon chain of MES destabilizes surfactant packing at the interface, increasing interfacial tension (IFT). The higher conductivity value of the ASP slug (15mS/cm) compared to the alkali-surfactant (AS) slug (7 mS/cm) indicates a strong electrostatic interaction caused by the rapid mobilization of free surfactant molecules across the PAM backbone at the water– oil interface. The lowest IFT value for ASP flooding was 0.28 mN/m. Sand pack flooding tests showed that the optimum PAM concentration in ASP flooding was 1,000 ppm, resulting in a 20-35% oil recovery. A negative effect of PAM on the oil recovery was observed at a higher PAM concentration of 9,000 ppm. IFT and mobility ratios were irregularly related to the oil recovery. At 1,000 ppm PAM, the oil recovery for ASP slug with MES and commercial surfactant sodium dodecyl sulfate (SDS) was 25% and 20%, respectively, indicating that MES is superior to SDS.

Attacks, Vulnerabilities and Security Requirements in Smart Metering Networks

( Muhammad Daniel Hafiz Abdullah ),( Zurina Mohd Hanapi ),( Zuriati Ahmad Zukarnain ),( Mohamad Afendee Mohamed ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.4

A smart meter is one of the core components in Advanced Metering Infrastructure (AMI) that is responsible for providing effective control and monitor of electrical energy consumptions. The multifunction tasks that a smart meter carries out such as facilitating two-way communication between utility providers and consumers, managing metering data, delivering anomalies reports, analyzing fault and power quality, simply show that there are huge amount of data exchange in smart metering networks (SMNs). These data are prone to security threats due to high dependability of SMNs on Internet-based communication, which is highly insecure. Therefore, there is a need to identify all possible security threats over this network and propose suitable countermeasures for securing the communication between smart meters and utility provider office. This paper studies the architecture of the smart grid communication networks, focuses on smart metering networks and discusses how such networks can be vulnerable to security attacks. This paper also presents current mechanisms that have been used to secure the smart metering networks from specific type of attacks in SMNs. Moreover, we highlight several open issues related to the security and privacy of SMNs which we anticipate could serve as baseline for future research directions.

Synthesis and performance evaluation of zeolitic imidazolate framework-8 membranes deposited onto alumina hollow fiber for desalination

Nizar Mu’ammar Mahpoz,Norfazliana Abdullah,Mohamad Zahir Mohd Pauzi,Mukhlis A. Rahman,Khairul Hamimah Abas,Azian Abd Aziz,Mohd Hafiz Dzarfan Othman,Juhana Jaafar,Ahmad Fauzi Ismail 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.3

This work describes the development of zeolitic imidazolate framework-8 (ZIF-8) membranes on modified alumina hollow fiber for desalination by forward osmosis. Effects of different seeds (ZnO, NiO and PDA) and sodium formate on in-situ deposition of ZIF-8 were studied in relation to the membrane’s morphology and performance. XRD result shows that ZIF-8 was successfully synthesized in the presence of sodium formate. FESEM images showed PDA modified support was unsuccessful in producing well defined and dense ZIF-8 membrane layer even after another ZIF-8 re-deposition due to its minimal amount. The NiO modified support was also found unsuccessful, as ZIF-8 crystals were formed in clusters. On the contrary, dense ZIF-8 membrane was successfully prepared on ZnO modified support with SF-1 synthesis solution producing bigger ZIF-8 crystal and thinner ZIF-8 membrane than as of SF-2. Water flux performance in forward osmosis showed that NiO/ZIF-8, PDA/ZIF-8 and PDA/ZIF-8 (re-deposition) membranes gave negative water fluxes of 50 kg/m2·h, 5.2 kg/m2·h and 1.7 kg/m2·h with reverse solutes of 42.66 mol/m2·h, 27.42mol/m2·h and 3.22 mol/m2·h, respectively, indicating the solute from draw solution diffused into the feed solution. However, ZIF-8 membrane prepared using SF with molar ratio of 1, on the ZnO modified support had a water flux of 13.3 kg/m2·h, reverse solute of 0.95 kg/m2·h and salt rejection of 52.1%. When the SF ratio was increased to 2, the ZIF-8 membranes showed a water flux of 12.5 kg/m2·h, reverse solute of 1.64 kg/m2·h and salt rejection of 54.9%. The moderate salt rejection could be associated with defects in the ZIF-8 membranes due to poor grain boundaries.

RRSEB: A Reliable Routing Scheme For Energy-Balancing Using A Self-Adaptive Method In Wireless Sensor Networks

( Ahmed M. Shamsan Saleh ),( Borhanuddin Mohd. Ali ),( Hafizal Mohamad ),( Mohd Fadlee A. Rasid ),( Alyani Ismail ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.7

Over recent years, enormous amounts of research in wireless sensor networks (WSNs) have been conducted, due to its multifarious applications such as in environmental monitoring, object tracking, disaster management, manufacturing, monitoring and control. In some of WSN applications dependent the energy-efficient and link reliability are demanded. Hence, this paper presents a routing protocol that considers these two criteria. We propose a new mechanism called Reliable Routing Scheme for Energy-Balanced (RRSEB) to reduce the packets dropped during the data communications. It is based on Swarm Intelligence (SI) using the Ant Colony Optimization (ACO) method. The RRSEB is a self-adaptive method to ensure the high routing reliability in WSNs, if the failures occur due to the movement of the sensor nodes or sensor node`s energy depletion. This is done by introducing a new method to create alternative paths together with the data routing obtained during the path discovery stage. The goal of this operation is to update and offer new routing information in order to construct the multiple paths resulting in an increased reliability of the sensor network. From the simulation, we have seen that the proposed method shows better results in terms of packet delivery ratio and energy efficiency.

Intelligent coordinated self-optimizing handover scheme for 4G/5G heterogeneous networks

Abdulraqeb Alhammadi,Wan Haslina Hassan,Ayman A. El-Saleh,Ibraheem Shayea,Hafizal Mohamad,Wasan Kadhim Saad 한국통신학회 2023 ICT Express Vol.9 No.2

Estimating the location of a target in search-and-rescue operations is quite challenging when the target is not responding. Therefore, in this paper, we investigate the passive target localization problem using mobile unmanned aerial vehicles (UAVs), where multiple mobile UAVs receive the time-difference-of-arrival (TDOA) measurements from the source UAV. Unlike traditional TDOA for static UAVs, the problem becomes more challenging when considering the mobility of UAVs. Therefore, we propose a novel TDOA model for target localization with mobile UAVs. We also measure the performance limit inequality between its Cramer-Rao lower bound (CRLB) and the mean-squared error (MSE).