Conducting polypyrrole (PPy) nanoparticles were synthesized by chemical oxidative polymerization of pyrrole in aqueous solution containing ferric sulfate (Fe2(SO4)3), anionic surfactants (sodium dodecylbenzene-sulfonate (NaDBS) or sodium dodecyl sulfate (SDS)), 1-pentanol as the oxidant, dopant and co-emulsifier, respectively. The polymerization was carried out at 0 ºC and 25 ºC. Fourier transform infrared spectroscopy (FTIR) and elemental analysis indicated that anionic surfactants were successfully incorporated into the PPy backbone. Incorporation of anionic surfactants caused enhanced electrical conductivity, increased yield, decreased the size of particles as well as improved the thermal stability of the resultant PPy. The presence of anionic surfactant seems to inhibit undesirable side reactions so as to improve the regularity of the PPy backbone. Globular PPy particles were obtained with diameter ranged from 40 to 118 nm as revealed by field emission scanning electron microscopy (FE-SEM) and conductivity of 7.89×10-4 –2.35×10-2 S cm-1, as measured using impedance analyzer. It was found that polymerization at low temperature (0 ºC) produced PPy particles with smaller size and higher conductivity. The sodium dodecyl sulfate-doped PPy (SDS-doped PPy) exhibited higher conductivity than that of the sodium dodecylbenzenesulfonate-doped PPy (NaDBS-doped PPy), due to the bulkiness of NaDBS as compared to SDS.
HCFCs, in addition to destroying the ozone layer, have been recognized as a contributing factor that increases global warming. It is widely used as working fluid in window air-conditioning system, where capillary tube serves as an expansion device. Literature reports have shown that no single refrigerant can solve the problem of ozone layer depletion and global warming. Refrigerant HC290/HC600a/HFC407C mixture, an eco-friendly refrigerant, has been recognized as an alternative to HCFC22. The objective of this study is to, for cost effectiveness, develop an empirical correlation to predict the refrigerant HC290/ HC600a/HFC407C mixture mass flow rate using statistical experimental design approach. A review of relevant literature shows that refrigerant’s mass flow rate depends on condensing temperature, degree of subcooling, inner diameter and length of capillary tube. The relationship between the mass flow rate and the four independent variables was established as an empirical mathematical correlation using central composite design (CCD), a response surface methodology (RSM). This empirical correlation was examined using analysis of variance (ANOVA) of 5% level of significance. The results of these analysis showed that the correlation fitted well with the experimental data yielding an average and standard deviation of 1.05% and 2.62%, respectively. The validity of the present correlation was further assessed by comparing it with published empirical correlation in literature and the result showed that the present correlation is consistent.
The growth performance of Indian major carp (Catla catla, Ham.) was assessed over a period of six months through formulated feeds consisting of three seaweeds, namely Chlorodesmis fastigiata, Padina tetrastomatica and Stoechospermum marginatum. A relatively slow average growth rate (6.48 g/month) in fishes was observed in the control group. Meanwhile, the maximum and rapid growth rate (13.38 g/month) was observed with Feed-A supplemented with C. fastigiata. Similarly, a comparable growth rate was also observed with Feed-B (11.56 g/month) with P. tetrastomatica. However, the growth rate in fishes was relatively lower (9.05 g/month) with Feed-C containing seaweed S.marginatum. The growth rate in each month was also compared. The maximum attainable growth rate was found to be 12 g in the control group, whereas this was 30 g with Feed-A. The attainable growth was 20 g and 15 g with Feed-B and Feed-C, respectively. In the control group, the maximum increments in weight was recorded in the third (September) and fifth (November) months of rearing, and the increment was considerably reduced after that. The maximum increment in weight was in the second month (August) with Feed-A, and this was followed by a considerable decrease in subsequent months. A similar trend was observed with Feed-B and Feed-C. The biochemical composition of all the four feeds used in the present study showed approximately the same protein (0.45-0.50 mg/ ml) and lipid contents (0.6 mg/ml). Carbohydrate was the only parameter which showed a relatively significant effect (p
The influence of elevated germanium concentration on the thermoluminesence characteristics of a novel
form of fabricated flat optical fibre was examined. All the samples were irradiated with two nominal
photon energies (6 MV and 10 MV) and 1.25 MeV gamma energy. Flat fibres with 10 mol % Ge
concentration provided the superior TL yield compared against that of 6 and 8 mol % Ge-doped optical
fibres for both 6 MV and 10 MV energy. Interpretation of the results has been aided by study of the glow
curves, revealing in particular new generation of defects in the flat fibres due to strain-generation at the
collapsed surfaces. The strain represent deep-energy defects.
Natural ventilation is defined as the number of air exchanges per hour per unit floor area necessary
to reduce high indoor air temperature and humidity. In addition, it maintains the concentration of carbon dioxide. Natural ventilation is preferred in mechanical system as the ventilation opening is built into the greenhouse, with lower construction cost and no energy and maintenance inputs are required. A mathematical model to quantify natural ventilation rates was developed and verified in large-scale greenhouse structures. For this purpose, four Naturally Ventilated Tropical Greenhouse Structures were designed and constructed at the Malaysian Agricultural Research and Development Institute (MARDI). These were single, double, triple, and quadruple span structures with floor areas of 500 m2, 1000 m2, 1500 m2 and 2000 m2, respectively. This paper presents the validation of a mathematical model which was developed to quantify natural ventilation rates which are very crucial to reduce high in-house temperature built up in the tropics. Regression equations of natural ventilation against wind speed were found to be Φw = 0.0632V, Φw= 0.0395V, Φw= 0.0316Vand Φw=0.0276V for the single, double, triple and quadruple spans, respectively. Meanwhile, coefficients of determination showed strong relationships between ventilation rate and wind speed, with R2 = 0.9999 for all structures. Larger floor area was found to have higher in-house temperature than smaller ones. Ventilation rate inside the single-span structure was found to be higher compared to the multi-span structures, which increased linearly with the increasing wind speed at the eaves of structure.
Experiments were conducted to determine the field and economic performances of machines and techniques for crop establishment in lowland paddy in Bangladesh. In machine seeded field, the crops were grown in rows to allow the operation of rotary type weeder for weed control. In hand broadcasted field, crops were not arranged in rows and weed control operation was therefore done through traditional means. Results obtained showed that the effect of rice seeding techniques, using pre-germinated rice seed of BR-1 variety on the effective field capacity, was highly significant. The work rate of hand broadcasting was found to be one to one and a half times faster than that of seeding by manually driven drum type row seeder. Field efficiency of hand broadcasting was about 90 percent, and this was found to be significantly higher than those of machine seeding which ranged from 70-80 percent at both seed rates, since no time was lost in turning. BRRI modified drum type row seeder, with a seeding rate of 60 kg/ha, was shown to be better for an optimum crop yield. Based on partial budget analysis, a farmer can save about US$53.34 per hectare in a year using the BRRI modified drum type row seeder, followed by a rotary weeder as compared to hand seeding, followed by hand weeding.
A field study was conducted on the effect of four primary tillage implements and three seed densities on the grain yield of rain fed wheat (Tajan cultivar), using a drill planting machine with the end wheels. The experimental design was a split plot design in a 4×3 factorial with three replications. In this study, the main plots were the tillage treatments, namely Mouldboard plough, Disc Plough, Chisel Plough, Offset Disc, and sub-plots were seed rates of 350, 400 and 450 seeds.m-2. Determinations included grain yield and selected yield components. The results showed that grain yield was not affected by the densities of seed and tillage machine treatments. The use of Chisel Plough, with 400 seeds.m-2 sowing rate, had the highest grain yield of wheat grown in the Golestan province (Iran), a region with an average annual rainfall of 450 mm.
Basal stem rot (BSR) caused by Ganoderma boninense is a major disease attacking the oil palm plantation in Malaysia, and incur big losses in palm oil industries. The disease is spread mostly by root either through spore availability in soil or roots contacts. Soil properties were reported to have significant influence on the growth of fungi. Meanwhile, the value of soil resistivity is influenced by soil properties. This paper presents a new approach of BSR detection by using soil moisture sensor which measures resistivity of soil in unit ohm (Ω) at 15 cm surrounding the basal stem of oil palm trees. The study was conducted on 39 oil palm trees at different healthiness levels. The sensor was embedded approximately 4.7 cm deep in the soil at eight different points for each palm. The results showed that healthy oil palm trees significantly have higher mean (ERMEAN ≥ 400) of electrical resistance (ER) readings compared to infected trees (ERMEAN< 400). More specifically, ER readings at points without symptoms (i.e. fruiting bodies and/or hollow) were significantly higher compared with ER readings at points where symptoms appeared even though the points of measurements were on the same palm. This finding has brought to the introduction of a new index to detect Ganoderma infection, named as K-index. Combination of ERMEAN taken from eight points of measurement and its K-index gave better results of detection and a new model was developed based on these two parameters (i.e. ERMEAN and K-index). The developed model has accuracy rates of 82% and gained 100% successful rate during validation. This research showed that soil resistivity can contribute to Ganoderma-infected detection in oil palms with a high degree of accuracy.
Complexity has been discussed in decision making, computational, task complexity, activity network,
supply chain, imaging, project management and mechanical. This paper reviews the definition of
complexity and the preliminary-related definitions of complexity index in decision making. It proposes
a complexity index for decision making, its properties, and implementation.
Cellulose I can be irreversible transformed into cellulose II via mercerisation or regeneration treatments.
In the past few decades, mercerisation was used mainly to improve fibre properties for textile industries.
A few studies have focused on the effects of mercerisation treatment on the cellulose polymorph itself
and after it was downscaled to nanosize. This study aims to characterise the micro size crystalline
cellulose after complete polymorph conversion via mercerisation technique and investigate its effects
on isolation to nanosize crystalline cellulose. A microcrystalline cellulose (MCC) was purchased and
converted into cellulose II via mercerisation technique. Sulphuric acid hydrolysis was carried-out
to produce nanocrystalline cellulose (NCC). The MCC and NCC of different polymorphs were then
characterised and analysed for its crystallography, morphology, particles size distribution and thermal
stability using wide-angle X-ray diffraction (WXRD), electron microscopes, dynamic light scattering
analyser and thermogravimetric analyser, respectively. Both MCC and NCC fibres showed complete
conversion of cellulose I to cellulose II and decrement of crystallinity index (CI). Electron micrographs
revealed that both cellulose II polymorph fibres (MCC II and NCC II) were morphological affected.
The analysis of size distribution and dimension
measurement confirmed that mercerisation
treatment causing increment in fibre diameter and
shortened length. The thermal stability of both
cellulose II polymorph fibres (MCC II and NCC
II) was also found to be improved.
The extract of Cinnamomum microphyllum showed strong antioxidant activity when it was tested against auto-oxidation of linoleic acid, superoxide, and DPPH radical scavenging activity. Further detailed investigations of the plant constituents and bioactivity studies led to the isolation and identification of known compounds consisting of three lignans, a coumarin, an ester and β-sitosterol. The structures of the compounds were determined using detailed spectroscopic analysis. The lignans were found to possess a significant antioxidant activity when tested against the three assay systems.
In this paper, a multi-objective analytical method to evaluate the impacts of optimal location and sizing
of distributed generation is presented. This method is based on an analysis of the exact loss formula and
continuous power flow in a radial distribution system. Based on two methods of analysis, power loss
and weakest voltage buses and lines are calculated and then the optimal size of distributed generation
is determined. After that, by considering the minimum power losses and the maximisation of voltage
stability, the proposed index determines and ranks positions to decide the optimal distributed generation
location in the system. This method allows us to find the best places and size to connect a number of
distributed generation units by optimising the objective functions. The simulation results were obtained
using a 33-bus radial distribution system to determine the location and size of the distributed generation
units. The results show the effectiveness of voltage profile improvement, loading factor improvement
and power loss reduction. Further, the problems of a single objective function and the placement of the
distributed generation unit using analytical methods are solved by the proposed approach.
Two imines of different molecular sizes namely 3-(phenylimino) indolin-2-one (PII) and 3,3- (1,4-phenylenebis (azan-1-yl-1-ylidene) diindolin-2-one (PDI) were investigated for their corrosion inhibition on mild steel in 1 M HCl solution using electrochemical impedance spectroscopy (EIS). The bigger molecule PDI containing double the amount of isatin moiety exhibited higher inhibition efficiency of 87.3% while PII that contained monoisatin moiety showed a lower inhibition efficiency of 74.8%. Both compounds had an increase in inhibition efficiencies percentage as concentrations increased. Density functional theory (DFT) was used to determine the correlation between the corrosion inhibition efficiency and electronic parameters. The DFT calculations indicated that the corrosion inhibition efficiency was mainly dependant on the frontier orbital energy gap and the chemical softness/hardness of the imines.
This paper focuses on examining the ‘cutting zone temperature’ while performing turning operation
on AZ91Mg alloy using cemented carbide tools. The regression model is developed by using the RSM
techniques based on experimental results. It is revealed that the cutting speed (v) is the most dominant
factor affecting cutting zone temperature. The developed models of cutting zone temperature sufficiently
map within the range of the turning conditions considered. The adequacy and accuracy of the regression
equation is justified through ANOVA. It is found that the optimal combinations of machining parameters
minimize the cutting temperature.
This paper investigates the effect of acid and silane treatment of Carbon Nanotubes (CNT) on wear properties of epoxy polymer composite. The wear test done was based on ASTM D3389 standard using the Abrasive Wear Tester (TR 600). Characterisation analysis was also done using Transmission Electron Microscopy (TEM) in order to study the dispersion of the CNT inside the epoxy matrix. When untreated CNT was added to the epoxy with amounts of 0.5, 0.75 and 1.0 wt%, the wear rates did not improve except for 0.5 wt% CNT filled epoxy. This was due to the lack of dispersion which causes larger chunks of material being dug out, thus contributing to a higher mass loss and wear rate. When treated with acid and silane, 0.75 wt% and 1.0 wt% CNT filled epoxy composites showed improvement. The TEM images of 0.5 wt%, 0.75 wt% and 1.0 wt% PCNT filled epoxy supported the claim of the lack of dispersion of PCNT inside the epoxy.
One of the best ways to enhance heat transfer coefficient is by improving thermal properties of the
working fluid. Gold/water nanofluid flow through horizontal minitube with very low Reynolds number
was simulated by using Thermal Lattice Boltzmann Method (TLBM) under uniform heat flux boundary
condition. The effect of different volume fraction of nanoparticles on the heat transfer coefficient was
studied and compared with the base fluid (water). The results were verified using Finite Volume Method
(FVM). The results showed enhancement of heat transfer coefficient when using gold/water nanofluid
and this enhancement depends on the volume concentration of Gold nanoparticles. The maximum
enhancement was 18% with 0.03 volume concentration.
This paper presents the numerical modelling techniques for the simulation of the energy conversion chain from wave to electricity in an Oscillating Water Column (OWC) equipped with a full-scaled self rectifying turbine. The performance of the OWC device has been assessed for the stand-alone power system of a typical Irish climatic wave condition. The results showed that the overall performance of the complete device depends on the level of turbine damping, which in turn depends on the wave climate, especially the significant wave height. Furthermore, turbine efficiency predicted using quasi-steady showed qualitatively favourable agreement with the experimental results.
Quercus infectoria gall, which is known as manjakani in Malaysia, was traditionally used in treating diseases. The bioactive compounds from the galls can be extracted using various extraction methods. In this study, supercritical carbon dioxide (SC-CO2) extraction was used to study the effects of CO2 flow rate on the yield, total phenolic content and antioxidant activity of Q. infectoria extract by fixing the pressure and temperature at the highest density (P: 30 MPa, T: 40°C). The results were compared with those acquired from the Soxhlet extraction method. The results showed that the Soxhlet extraction had a higher percentage of extraction yield than SC-CO2 extraction. The selectivity of Q. infectoria extracts using SC-CO2 extraction was better than the Soxhlet extraction method. Meanwhile, the extraction efficiency using the SC-CO2 extraction ranged from 46% to 53%. The SC-CO2 extraction also yielded higher total phenolic content than using the Soxhlet extraction method when 2 mL/min of CO2 flow rate was applied (203.53 mg GA/g sample). This study also revealed that the extracts from the SC-CO2 extraction showed a better radical scavenging activity compared to the Soxhlet extraction when analysed using DPPH (2,2-diphenyl-1-picryl hydrazyl) radical scavenging activity assays.radical scavenging activity compared to the Soxhlet extraction when analysed using DPPH (2,2-diphenyl-1-picryl hydrazyl) radical scavenging activity assays.
Diabetes is one of the major life-threatening health problems worldwide today. It is one of the most fastgrowing diseases that cause many health complications and a leading cause of decreasing life expectancy and high mortality rate. Many studies have suggested several different types of intervention to treat Type 1 diabetes such as insulin therapy, islet transplantation, islet xenotransplantation and stem cell therapy. However, issues regarding the efficacy, cost and safety of these treatments are not always well addressed. For decades, diabetes treatments with few side effects and long-lasting insulin independence has remained one of the most challenging tasks facing scientists. Among the treatments mentioned above, application of human islet transplantation in patients with type 1 diabetes has progressed rapidly with significant achievement. Again, the lack of appropriate donors for islet transplantation and its high cost have led researchers to look for other alternatives. In this review, we discuss very pertinent issues that are related to diabetes treatments, their availability, advantages, disadvantages and also cost,
The long term objective of this research is to look into the possibility of replacing soil strength parameters such as cohesion and angle of friction with electrical resistivity value for the purpose of computing among others, factor of safety in slopes or bearing capacity of soil. This paper however is limited to the investigation of correlation between electrical resistivity with some selected soil parameters. Electrical resistivity tests, using a basic multi meter, steel moulds and other related equipment, were conducted in the laboratory on soil samples with variations in soil type, compaction energy and moisture content. The samples consisted of predominantly clay, silt and sandy size particles and were compacted in a 100 x 100 mm square mould, while the corresponding electrical resistivity tests were carried out using the disc electrode method in accordance to BS 1377. The values of the electrical parameters such as voltage, current and resistance, with the corresponding value of soil parameters such as cohesion, angle of friction and moisture content, were measured and recorded. The results of the tests produced some initial crude relationships between electrical resistivity and the selected soil parameters. The strongest correlation between electrical resistivity and angle of internal friction, φ, was obtained from the clay size samples with R2 of 0.824, while the maximum correlation between electrical resistivity and moisture content again was obtained through the clay samples with R2 of 0.818. From the other results and graphs analyzed, some consistencies and specific trends of behaviour observed gave some early indications that a more detail and precise correlation between electrical resistivity and soil strength parameters could be very well possible in future.