Showing papers by "Universiti Teknologi Petronas published in 2013"

Eco-Friendly Extraction and Characterization of Cellulose from Oil Palm Empty Fruit Bunches

Abstract: Cellulosic fibers in Oil Palm Empty Fruit Bunches (OPEFB) are tightly packed with lignin, hemicelluloses, small depositions of wax, and inorganic elements. In the present work, eco-friendly reagents with low concentrations of 20% (v/v) formic acid and 10% (v/v) of 30% hydrogen peroxide were employed at 85 oC for the extraction of cellulose from OPEFB. The yield of 64% (w/w) achieved was among the highest ever reported. Based on the XRD, the alpha-cellulose content was 93.7% with a high crystallinity of 69.9%. The average diameter was 13.5 μm with structural evidence of separated fibrils as investigated by FESEM. The TEM analysis suggested that the material was crystalline and its geometry was a monoclinic structure. The FTIR spectral peaks representing wax and hemicelluloses at 1735 cm-1 and 1375 cm-1, respectively, and lignin at 1248 cm-1 and 1037 cm-1, were not observed in the extracted OPEFB-cellulose spectra. Based on the TGA results, thermal stability at 325 °C with a single degradation curve suggests the purity of OPEFB-cellulose.

Recent Applications of Polymer Blends in Gas Separation Membranes

Abstract: Polymeric membranes are extensively used for gas separations but their performance is limited by the upper bound trade-off discovered by Robeson in 1991. Among the attractive modifications available to increase the performance of polymeric membranes, polymer blending is a unique technique because it offers a time- and cost-effective method of tuning the properties of membranes. A variety of polymer blends has been explored in recent years. The application of polymer blends in gas separation membranes is described by critically analyzing the performance of polymer blend membranes. Polymer blend membranes of different polymer pairs are reviewed and evaluated in terms of phase behavior, permeability, and selectivity.

Material Advancements in Fabrication of Mixed‐Matrix Membranes

Abstract: The mixed-matrix membrane (MMM) is a new membrane material for gas separation and plays a vital role for the advancement of current membrane-based separation technology. Blending between inorganic fillers like carbon molecular sieves, zeolite, metal oxides, silica and silica nanoparticles, carbon nanotubes, zeolitic imidazolate framework, metal organic framework, and glassy and rubbery polymers etc. is possible. Due to mechanical, thermal, and chemical stability, these membranes achieve high permeability and selectivity as compared to pure polymeric materials. Despite of these advantages, the MMM performances are still below industrial expectations because of membrane defects and related processing problems as well as the nonuniform dispersion of fillers in MMMs. Material selection for organic and inorganic phases, preparation techniques, material advancements, and performance of MMMs are discussed. Issues and challenges faced during MMM synthesis as well as problem solutions are highlighted.

Effects of torrefaction on the physiochemical properties of oil palm empty fruit bunches, mesocarp fiber and kernel shell.

Abstract: In this work, the effects of torrefaction on the physiochemical properties of empty fruit bunches (EFB), palm mesocarp fiber (PMF) and palm kernel shell (PKS) are investigated. The change of properties of these biomass residues such as CHNS mass fraction, gross calorific value (GCV), mass and energy yields and surface structure when subjected to torrefaction process are studied. In this work, these materials with particle size in the range of 355–500 μm are torrefied under light torrefaction conditions (200, 220 and 240 °C) and severe torrefaction conditions (260, 280 and 300 °C). TGA is used to monitor the mass loss during torrefaction while tube furnace is used to produce significant amount of products for chemical analyses. In general, the study reveals torrefaction process of palm oil biomass can be divided into two main stages through the observation on the mass loss distribution. The first stage is the dehydration process at the temperature below than 105 °C where the mass loss is in the range of 3–5%. In the second stage, the decomposition reaction takes place at temperature of 200–300 °C. Furthermore, the study reveals that carbon mass fraction and gross calorific value (GCV) increase with the increase of torrefaction temperature but the O/C ratio, hydrogen and oxygen mass fractions decrease for all biomass. Among the biomass, torrefied PKS has the highest carbon mass fraction of 55.6% when torrefied at 300 °C while PMF has the highest GCV of 23.73 MJ kg−1 when torrefied at the same temperature. Both EFB and PMF produce lower mass fraction than PKS when subjected to same torrefaction temperature. In terms of energy yield, PKS produces 86–92% yield when torrefied at light to severe torrefaction conditions, until 280 °C. However, both EFB and PMF only produce 70–78% yield at light torrefaction conditions, until 240 °C. Overall, the mass loss of 45–55% of these biomasses is observed when subjected to torrefaction process. Moreover, SEM images reveal that torrefaction has more severe impact on surface structure of EFB and PMF than that of PKS especially under severe torrefaction conditions. The study concludes that the torrefaction process of these biomass has to be optimized based on the type of the biomass in order to offset the mass loss of these materials through the process and increase the energy value of the solid product.

GIS-based analytic hierarchy process as a multicriteria decision analysis instrument: a review

Abstract: Information and communication technology, which has been incorporated and provided in the Geographic Information System (GIS), is valuable and effective geospatial information for the decision makers in improving their decisions in planning and development. The integration of this GIS using the multicriteria decision analysis approach provides an environment to the decision makers in citing areas using land suitability analysis procedures. This review paper particularly examines the GIS-based analytic hierarchy process as a multicriteria analysis/evaluation technique in land suitability analysis by means of literature reviews and surveys.

A Jatropha biomass as renewable materials for biocomposites and its applications.

Abstract: This review deals with the study of Jatropha biomass as renewable materials for biocomposites and its applications. Jatropha curcas is a multipurpose plant with many attributes and considerable potential. Jatropha plant is cultivated worldwide but it has specific cultivation area in Central and South America, Africa, and South Asia. The Jatropha plant produces many useful products, especially the seed from which oil can be extracted. Extracted oil has similar properties to palm oil and possible to obtain many products after processing. As biomass, Jatropha plant can used as a reinforcement in biocomposite development. Jatropha contain high amount of carbon especially in seed/husk, fruit shell and seed cake and can be used as filler in composite fabrication in the form of carbon black and activated carbon. In this review, we will discuss the distribution of Jatropha around the globe, chemical composition of various parts and extracts of Jatropha and their mechanical and physical properties. We will also cover the use of Jatropha biomass in various technical and biocomposite applications. With the development of green technology, Jatropha latex can be reduced to nanoparticle size. The chemical and physical properties of Jatropha contribute to its applications in food and non-food Products.

Original Article: Analysis of distance metrics in content-based image retrieval using statistical quantized histogram texture features in the DCT domain

Abstract: The effective content-based image retrieval (CBIR) needs efficient extraction of low level features like color, texture and shapes for indexing and fast query image matching with indexed images for the retrieval of similar images. Features are extracted from images in pixel and compressed domains. However, now most of the existing images are in compressed formats like JPEG using DCT (discrete cosine transformation). In this paper we study the issues of efficient extraction of features and the effective matching of images in the compressed domain. In our method the quantized histogram statistical texture features are extracted from the DCT blocks of the image using the significant energy of the DC and the first three AC coefficients of the blocks. For the effective matching of the image with images, various distance metrics are used to measure similarities using texture features. The analysis of the effective CBIR is performed on the basis of various distance metrics in different number of quantization bins. The proposed method is tested by using Corel image database and the experimental results show that our method has robust image retrieval for various distance metrics with different histogram quantization in a compressed domain.

Static adsorption of anionic surfactant onto crushed Berea sandstone

Abstract: Surfactant adsorption in porous media is one of the major criteria which decide the economic viability of surfactant flooding in chemical enhance oil recovery applications (CEOR). In this study, the static adsorption of a novel in-house synthesized anionic surfactant was investigated onto crushed Berea sandstone. The point of zero (PZC) charge for Berea sandstone and critical micelle concentration (CMC) of anionic surfactant are also reported in this paper. The investigated PZC for Berea core was at pH 8.0 and the maximum adsorption of anionic surfactant was 0.96 mg/g. Furthermore, the effects of alkali, salinity and temperature on static adsorption of anionic surfactant were investigated at variable conditions. It was concluded that the anionic surfactant performs better at higher pH, higher temperature and lower salt concentration. An effective control of all these parameters can lead to the situation which helps in minimizing the surfactant loss and improved economic efficiency of CEOR process.

Late Aptian long‐lived glacio‐eustatic lowstand recorded on the Arabian Plate

Abstract: Terra Nova, 25, 87–94, 2013 Abstract Compelling physical evidence for a Late Aptian lowstand with an amplitude of at least 50 m is presented in subsurface seismic and core data from the Arabian Plate. Biostratigraphic dating indicates that the fall and rise bracketing this lowstand were rapid, and that the lowstand lasted for around 5 ma with distinctly cyclic sedimentation at the 0.4–0.5 ma scale (eccentricity band). A glacio-eustatic mechanism is invoked as the most likely cause, which is supported by cooling indicated in oxygen isotope shifts and by evidence for a global expression of this lowstand from a number of locations at the mid and high latitudes. Hence, the Late Aptian data presented here document the longest Cretaceous sea-level lowstand, interpreted as the longest cooling phase during the Cretaceous greenhouse.

Development and characterization of epoxy nanocomposites based on nano-structured oil palm ash

Abstract: The aim of this study is to utilize the bio-agricultural waste as filler material for composite production which are abundantly available and low cost compared to the silica, alumina etc The lacks of sufficient scientific information about the utilization of the oil palm ash (OPA) on composites production were the driving force for the choice of this work Furthermore, the effect of filler loading percentage on physical, mechanical, thermal and morphology properties of the epoxy nanocomposites were studied It was concluded that the size of the OPA had been successfully reduced from macromolecular to the nano-size range by high energy ball milling and was confirmed by TEM analysis The density of the nano-structured OPA filled epoxy composites revealed that increasing filler loading will eventually increase the density The tensile and flexural strength attained maximum value when the filler loading was 3% Also, increase in the thermal stability was observed in case of 3% filler loading and was attributed to the increase in cross-linking of the epoxy resin in the presence of nano-stuctured OPA and having minimum particle to particle interaction and well dispersed nanoparticles

Synthesis, characterization and enhanced thermoelectric performance of structurally ordered cable-like novel polyaniline-bismuth telluride nanocomposite.

Abstract: Bismuth telluride (Bi2Te3) nanorods and polyaniline (PANI) nanoparticles have been synthesized by employing solvothermal and chemical oxidative processes, respectively. Nanocomposites, comprising structurally ordered PANI preferentially grown along the surface of a Bi2Te3 nanorods template, are synthesized using in situ polymerization. X-ray powder diffraction, UV–vis and Raman spectral analysis confirm the highly ordered chain structure of PANI on Bi2Te3 nanorods, leading to a higher extent of doping, higher chain mobility and enhancement of the thermoelectric performance. Above 380 K, the PANI–Bi2Te3 nanocomposite with a core–shell/cable-like structure exhibits a higher thermoelectric power factor than either pure PANI or Bi2Te3. At room temperature the thermal conductivity of the composite is lower than that of its pure constituents, due to selective phonon scattering by the nanointerfaces designed in the PANI–Bi2Te3 nanocable structures. The figure of merit of the nanocomposite at room temperature is comparable to the values reported in the literature for bulk polymer-based composite thermoelectric materials.

Effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete

Abstract: The effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete (SCGC) was investigated in this paper. The work focused on the concrete mixes with a fixed water-to-geopolymer solid (W/Gs) ratio of 0.33 by mass and a constant total binder content of 400 kg/m3. The mass fractions of silica fume that replaced fly ash in this research were 0wt%, 5wt%, 10wt%, and 15wt%. The workability-related fresh properties of SCGC were assessed through slump flow, V-funnel, and L-box test methods. Hardened concrete tests were limited to compressive, splitting tensile and flexural strengths, all of which were measured at the age of 1, 7, and 28 d after 48-h oven curing. The results indicate that the addition of silica fume as a partial replacement of fly ash results in the loss of workability; nevertheless, the mechanical properties of hardened SCGC are significantly improved by incorporating silica fume, especially up to 10wt%. Applying this percentage of silica fume results in 4.3% reduction in the slump flow; however, it increases the compressive strength by 6.9%, tensile strength by 12.8% and flexural strength by 11.5%.

Effect of boric acid and melamine on the intumescent fire-retardant coating composition for the fire protection of structural steel substrates

Abstract: Intumescent coating is an insulating material designed to decrease heat transfer to a substrate structure. The coating presented in this research article was based on expandable graphite, ammonium polyphosphate, melamine, and boric acid. Bisphenol A epoxy resin BE-188 was used as a binder with ACR hardener H-2310 polyamide amine. Different formulations were developed to study the effect of expansion and heat shielding after fire testing. The coating was tested at 950°C for 1 h. The results show that the coating was stable and well bonded with the substrate. The coating was characterized with thermogravimetric analysis (TGA, Parkin Elmer, Norwalk, CT, 06859, USA), Fourier transform infrared (FTIR, Nicolet 400 D Shimadzu spectrometer) spectroscopy, X-ray diffraction (XRD, Bruker D8 advance Diffracto meter, Bruker Germany), and scanning electron microscopy (SEM, Carl Zeiss Leo 1430VP, UK). The morphology of char was studied by SEM on the coating after fire testing. XRD and FTIR spectroscopy showed the presence of graphite, boron phosphate, boron oxide, and sassolite in the residual char. TGA (Pyris 1, manufactured by Parkin Elmer, Norwalk, CT, 06859, USA) and differential thermal gravimetric analysis (DTGA) showed that boric acid enhanced the residual weight of the intumescent fire-retardant coating. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Prevention of DoS Attacks in VANET

Abstract: Privacy and Security have become an indispensable matter of attention in the Vehicular Ad-Hoc Network, which is vulnerable to many security threats these days. One of them is the Denial of Service (DoS) attacks, where a malicious node forges a large number of fake identities, i.e., Internet Protocol (IP) addresses in order to disrupt the proper functioning of fair data transfer between two fast-moving vehicles. In this paper, a distributed and robust approach is presented to defend against DoS attacks. In this proposed scheme, the fake identities of malicious vehicles are analyzed with the help of consistent existing IP address information. Beacon packets are exchanged periodically by all the vehicles to announce their presence and to become aware of the next node. Each node periodically keeps a record of its database by exchanging the information in its environment. If some nodes observe that they have similar IP addresses in the database, these similar IP addresses are identified as DoS attacks. However, it can be expected that security attacks are likely to increase in the coming future due to more and more wireless applications being developed onto the well-known exposed nature of the wireless medium. In this respect, the network availability is exposed to many types of attacks. A DoS attack on the network availability is being elaborated in this paper. A model of a product interaction for DoS prevention has been developed called "IP-CHOCK" that will lead to the prevention of DoS attacks. The proposed approach will be able to locate malicious nodes without the requirement of any secret information exchange and special hardware support. Simulation results demonstrate that the detection rate increases when optimal numbers of nodes are forged by the attackers.

A wideband, frequency up-converting bounded vibration energy harvester for a low-frequency environment

Abstract: This paper presents a bounded vibration energy harvester to effectively harvest energy from a wide band of low-frequency environmental vibrations ranging from 10 to 18 Hz. Rigid mechanical stoppers are used to confine the seismic mass movement within the elastic limits of the spring. Experimental results show the effectiveness of the proposed technique in increasing the efficiency of the energy harvester. When excited at a frequency of 10 Hz with a peak acceleration of 1 g, the harvester responds at a higher frequency of 20 Hz and gives a peak power of 2.68 mW and a peak to peak voltage of 2.62 V across a load of 220 Ω. The average power density of 65.74 μW cm−3 obtained at 10 Hz 1 g excitation monotonically increases with frequency up to 341.86 μW cm−3 at 18 Hz. An analytical model describing the nonlinear dynamics of the proposed harvester is also presented. A simple technique to estimate the energy losses during impact and thereof a method to incorporate these losses in the model are suggested. The presented model not only predicts the experimental voltage waveform and frequency response of the device with good similarity but also predicts the RMS voltage from the harvester for the whole range of operating frequencies with an RMS error of 5.2%.

Natural fiber reinforced poly(vinyl chloride) composites : a review.

Abstract: Materials from renewable resources – also called biomaterials or ‘green’ materials – are presently gaining in importance worldwide. In these times of continuous increases in the price of crude oil ...

Recent advances on power distribution system planning: a state-of-the-art survey

Abstract: The rise in installation/reinforcement and maintenance costs of power distribution systems enforces the planner to adopt an optimal strategy during system planning. The planning should be uch that the designed system should economically and reliably take care of spatial and temporal load growth, and service area expansion in the planning horizon. Mathematically, this planning is a multivariable multi-objective optimization problem. During the past decade or so, several planning algorithms have been developed. The purpose of this survey is to present a comprehensive review of all the developments in the planning technology, which includes all the reported optimization models and solution strategies. This state-of-the art survey is systematically organized to serve as a stepping stone for future researchers as well as a planning guide for the engineers. The various planning models are grouped in a three-level classification structure starting with two broad categories, i.e., planning without and with reliability considerations. The tree grows further with subdivisions. The last level of this classification tree consists of different planning models and solution strategies. Comprehensive discussions on each planning model are presented.

Techno-economic analysis of potential natural gas liquid (NGL) recovery processes under variations of feed compositions

Abstract: This paper presents the different process schemes used for known NGL recovery methods with respect to their economic performance. The original turbo-expander (ISS) was considered as base case plant. The GSP, CRR and RSV process schemes focus on improvement at the top of the demethanizer column. The IPSI-1 and IPSI-2 schemes focus on the bottom of the demethanizer column. All the process schemes were initially built using Aspen HYSYS with a common set of operating criteria. Numerous simulation runs were made by taking various typical feed compositions classified as lean and rich. The economic assessment for each process scheme was later made by considering the capital cost, operating cost and profitability analysis. Results showed that the IPSI-1 process scheme gives the best economic performance with lowest TAC and payback time compared to the other process schemes. On the other hand, the RSV process gives higher TAC and payback time compared to others.

Improved energy harvesting from low frequency vibrations by resonance amplification at multiple frequencies

Abstract: This paper reports on an electromagnetic vibration energy harvester that utilizes a novel method of energy pumping based frequency up-conversion to effectively harvest energy from a broad range of low frequency (