The performance of modified jatropha-based nanofluid during turning process

The industry's extensive use of petroleum-based metalworking fluid (MWF) harms the environment and humans. The production of bio-based MWF, especially from crude jatropha oil (CJO), has therefore taken numerous initiatives. This aimed to formulate newly modified jatropha oil (MJO) with the addition of 0.05wt.% hBN and 0.05wt.% MoS2 as the nanofluid for MWF. The performance of the nanofluids was determined through the turning process in terms of cutting temperature, workpiece surface roughness, tool life and tool wear of the tool lubricated by the nanofluids. The performance of the nanofluid samples was compared with the synthetic ester (SE). From the results, after conducted 100mm axial cutting length MJO+hBN+MoS2 recorded the lowest in cutting temperature and surface roughness compared to all samples. The result shows that MJO+hBN+MoS2 has longer tool life (6500mm) compared to SE (6000mm). Abrasion and adhesion were observed as the dominant tool wear mechanism. In conclusion, MJO+hBN+MoS2 shows better machining performance and has the potential to be an environmentally friendly metalworking fluid

Polyethersulfone/HFO mixed matrix membrane for enhanced oily wastewater rejection

The recent growth of oil and gas industry has led to the increase of oily wastewater release. Membrane technology has been in the spotlight in recent advancement to treat the oily wastewater. Fouling due to surfactant adsorption and/or oil droplets plugging the pore has become one of the major hindrances in most of the research on oily wastewater treatment. In this work, self-synthesized hydrous ferric dioxide nanoparticles (HFO NPs) via chemical precipitation method were incorporated in polyethersulfone (PES) to fabricate a novel nanocomposite mixed matrix membranes (MMMs) for ultrafiltration (UF). The morphologies and physicochemical properties of prepared HFO NPs and MMMs were characterized using Scanning Electron Microscopy (SEM) and Transmission electron microscope (TEM), contact angle goniometer, before further subjected to water permeation test and oil rejection test. It was found that contact angle of membrane decreased remarkably with an increase in HFO nanoparticle loading from 70° to 38° at which proved its improved hydrophilicity which led to a significant rise in permeate flux, achieving 168.06 L/m2h bar in comparison to 63.67 L/m2h bar shown by the plain PES membrane. Total rejection of oil (100% rejection) demonstrated by the MMMs has confirmed the superior potential of PES/HFO UF membrane for total purification of oily wastewater especially to be reused in oilfield and refinery processes as well as to be released to the environment

Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures

Physico-chemical parameters and trophic status of an acidic lake in Hutan Simpan Ayer Hitam, Puchong

Relationship between physico-chemical parameters including pH, Temperature, total dissolved solid, dissolved oxygen, light intensity, ammonia, nitrate, silica, and phosphate with microalgae diversity were studied. Water sampling water was conducted biweekly for 4 months from October 2015 to February 2016 for 15 weeks in North Lake of Hutan Simpan Ayer Hitam Puchong. Physico-chemical parameters were determined at site and laboratory. Data analysis including Pearson Correlation Analysis, Principal Component Analysis, and Canonical Correspondence Analysis were carried out. Green algae, Staurastrum sp. and Chlamydomonas have a positive correlation with pH and total dissolved solid. Cosmarium spp. have a positive correlation with dissolved oxygen and have association with increased pH and ammonia. Diatom, Navicula sp. have high negative correlation with pH and have association with increased of silica. Dinoflagellates, Gymnodinium sp. and Gonyaulax apiculata both have high negative correlation with pH. Gymnodinium sp. have association with increased phosphate and temperature. Gonyaulax apiculata have a positive correlation with temperature. Based on research, this lake were slightly acidic but remains oligotrophic North Lake of Hutan Simpan Ayer Hitam Puchong are acidic but oligotrophic due to pH in range of acidic condition but below the boundary of phosphate concentration from 0.01mg/L to 0.075mg/L suggested by USEPA (2002) in aquatic systems

Current status of algae biodiversity and succession in North Lake of Hutan Simpan Ayer Hitam, Puchong

This study presents data on the diversity and succession of algae in North Lake, Hutan Simpan Air Hitam (HSAH) as well as its relationship with chemical and physical factors. Algae samples were collected weekly from three different sites in North Lake started from October 2015 until January 2016 (15 weeks). Physico-chemical parameters such as pH, temperature, light, dissolved oxygen (DO), total dissolved solid (TDS) and nutrients statuses were measured simultaneously. A total of 18 species were recorded comprising Bacillariophyta (3 species), Charophyta (4 species), Chlorophyta (4 species), Cyanobacteria (2 species), Dinophyta (4 species), and Ochrophyta (1 species). The highest total density of algal cells were phyla Dinophyta (24%) followed by Charophyta (22%), Bacillariophyta (19%), Ochrophyta (18%), Cyanophyta (10%) and Chlorophyta (7%). Dinobryon sertularia was the most frequent species found throughout the 15 weeks of sampling and became dominant in week 3, 4, 6, 10 and 13; whereas Staurastrum sp. achieved the highest algal counts in week 1 and 2. Gonyaulax apiculata was dominant during week 5, 8, 14 and 15. The Shannon-Weaver diversity Index, H’ classified North Lake as being moderately polluted, whereas the pH values indicates that the lake was quite acidic by having pH lower than 7 and ranged between 4.28 and 5.57. The occurrence of some phytoplankton groups may be influenced by pH, as has been found in acidic natural lakes and also in extremely acidic lakes around the world. In addition, other physico-chemical factors may also give impact on algae structure and community

A combined spectrum sensing method based DCT for cognitive radio system

In this paper a new hybrid blind spectrum sensing method is proposed. The method is designed to enhance the detection performance of Conventional Energy Detector (CED) through combining it with a proposed sensing module based on Discrete Cosine Transform (DCT) coefficient’s relationship as operation mode at low Signal to Noise Ratio (SNR) values. In the proposed sensing module a certain factor called Average Ratio (AR) represent the ratio of energy in DCT coefficients is utilized to identify the presence of the Primary User (PU) signal. The simulation results show that the proposed method improves PU detection especially at low SNR values

Energy Consumption Control in Cooperative and Non-Cooperative Cognitive Radio using Variable Spectrum Sensing Sampling

In cognitive radio (CR) network, the concept of energy-efficient design is very important considering the costly energy consumption that may limit its implementation, especially in battery-powered devices. In these networks, significant part of the energy is consumed in the energy detector during spectrum sensing to detect the presence and absence of the primary user (PU). In this paper, we investigated the reduction of energy consumption in two scenarios: the non-cooperative scenario and the cooperative scenario by reducing the number of sensed samples. We also explained the optimisation criteria for improving energy consumption by controlling the number of sensed samples, and the detection probability in both scenarios. The performance of energy detection system was evaluated in AWGN and Rayleigh fading channels. The simulation results show that in non-cooperative scenario at Eb/No of 10 dB, 50% and 46% of the energy consumed in the detection was saved when the number of sensed samples was reduced by 50% with acceptable loss in detection probability of 5% and 12% in AWGN and Rayleigh channel respectively. In cooperative scenario, the result shows that increasing the number of cognitive users (CU) reduced the average energy consumption per sensor and improved the detection probability

On the Primacy of the Exchange Complex on the Shear Strength of Marly Soil

The influence of the exchange complex on shear strength behavior and the initial tangent modulus of elasticity of marly soil (a low active soil) were investigated. The investigation involved transformation of the naturally heterogeneous exchange complex into homogeneous exchange complex having only one type of exchangeable cation species present in the exchange complex. This step constitutes a fundamental step for assessing soil behavior of natural heterogeneous exchange complexes based on the physicochemical approach. Although the investigated soil is a low active soil, the influence of the exchange complex on shear strength was significant, or even substantial in some cases. Differences in soil cohesion associated with the tested exchange complexes reached 3 folds, and differences in the angle of friction reached about 50% to 90%, depending on the dry density of the soil and its moisture content. Influence of the exchange complex was minor on the exponent "n" of Janbu’s formula; maximum variation was about 25%. A change in Kur which is the second parameter of Janbu’s formula due to changes in the exchange complex was substantial; variation reached as much as three folds

Differentiation of Lactobacillus-probiotic strains by visual comparison of random amplified polymorphic DNA (RAPD) profiles

In the present study, distinctive RAPD fingerprints were generated for 12 Lactobacillus-probiotic strains from 5 Lactobacillus species (L. brevis, L. reuteri, L. gallinarium, L. salivarius and L. panis) after optimization of the RAPD parameters such as MgCl2, Taq polymerase, primer concentration and type of primer. The strains were differentiated under the same PCR protocol but different concentration of primer OPM-05 (50 pmole to differentiate the 5 L. brevis strains and 75 pmole to differentiate 2 strains of L. gallinarium, 3 strains of L. reuteri, a strain of L. panis and L. salivarius). The RAPD fingerprints generated could be differentiated by visual comparison of the profiles, without being analysed by relevant software. This allows specific, rapid, immediate and convenient identification of the Lactobacillus strains