Abstract: In this research, the effects of the engine parameters like compression ratios and steam injection on igniting timing and emission characteristics have been investigated numerically. The in-cylinder temperature and pressure at four different compression ratios have been compared with numerical results, and they show a good agreement with the published data. Two different fuels have been used in this study: Isooctane (IC8H18), and ethanol (C2H5OH). The increasing of the compression ratio (CR) advances the ignition timing, decreases the burn duration and increases the temperature and the pressure. The injection of water vapor lower than 40% decreased the peak temperature and slowed the combustion rate which leads to a lower NOx emission.
Abstract: This paper aims to explore the role of peer Corrective Feedback (CF) in improving written productions by English-as-a- foreign-language (EFL) learners who work together via Wikispaces. It attempted to determine the effect of peer CF on form accuracy in English, such as grammar and lexis. Thirty-four EFL learners at the tertiary level were randomly assigned into the experimental (with peer feedback) or the control (without peer feedback) group; each group was subdivided into small groups of two or three. This resulted in six and seven small groups in the experimental and control groups, respectively. In the experimental group, each learner played a role as an assessor (providing feedback to others), as well as an assessee (receiving feedback from others). Each participant was asked to compose his/her written work and revise it based on the feedback. In the control group, on the other hand, learners neither provided nor received feedback but composed and revised their written work on their own. Data collected from learners’ compositions and post-task interviews were analyzed and reported in this study. Following the completeness of three writing tasks, 10 participants were selected and interviewed individually regarding their perception of collaborative learning in the Computer-Mediated Communication (CMC) environment. Language aspects to be analyzed included lexis (e.g., appropriate use of words), verb tenses (e.g., present and past simple), prepositions (e.g., in, on, and between), nouns, and articles (e.g., a/an). Feedback types consisted of CF, affective, suggestive, and didactic. Frequencies of feedback types and the accuracy of the language aspects were calculated. The results first suggested that accurate items were found more in the experimental group than in the control group. Such results entail that those who worked collaboratively outperformed those who worked non-collaboratively on the accuracy of linguistic aspects. Furthermore, the first type of CF (e.g., corrections directly related to linguistic errors) was found to be the most frequently employed type, whereas affective and didactic were the least used by the experimental group. The results further indicated that most participants perceived that peer CF was helpful in improving the language accuracy, and they demonstrated a favorable attitude toward working with others in the CMC environment. Moreover, some participants stated that when they provided feedback to their peers, they tended to pay attention to linguistic errors in their peers’ work but overlook their own errors (e.g., past simple tense) when writing. Finally, L2 or FL teachers or practitioners are encouraged to employ CMC technologies to train their students to give each other feedback in writing to improve the accuracy of the language and to motivate them to attend to the language system.
Abstract: In this work, obtaining methods of ultrafine alumina
powdery composites and high temperature pressing technology of
matrix ceramic composites with different compositions have been
discussed. Alumina was obtained by solution combustion synthesis
and sol-gel methods. Metal carbides containing powdery composites
were obtained by homogenization of finishing powders in nanomills,
as well as by their single-step high temperature synthesis .Different
types of matrix ceramics composites (α-Al2O3-ZrO2-Y2O3, α-Al2O3-
Y2O3-MgO, α-Al2O3-SiC-Y2O3, α-Al2O3-WC-Co-Y2O3, α-Al2O3-
B4C-Y2O3, α-Al2O3- B4C-TiB2 etc.) were obtained by using OXYGON
furnace. Consolidation of powders were carried out at 1550-
1750°C (hold time - 1 h, pressure - 50 MPa). Corundum ceramics
samples have been obtained and characterized by high hardness and
fracture toughness, absence of open porosity, high corrosion
resistance. Their density reaches 99.5-99.6% TD. During the work,
the following devices have been used: High temperature vacuum
furnace OXY-GON Industries Inc (USA), Electronic Scanning
Microscopes Nikon Eclipse LV 150, Optical Microscope NMM-
800TRF, Planetary mill Pulverisette 7 premium line, Shimadzu
Dynamic Ultra Micro Hardness Tester DUH-211S, Analysette 12
Dynasizer.
Abstract: Entropy, as an outcome of the second law of thermodynamics, measures the level of irreversibility associated with any process. The identification and reduction of irreversibility in the energy conversion process helps to improve the efficiency of the system. The entropy of pure substances known as absolute entropy is determined at an absolute reference point and is useful in the thermodynamic analysis of chemical reactions; however, municipal solid waste (MSW) is a structurally complicated material with unknown absolute entropy. In this work, an empirical model to calculate the absolute entropy of MSW based on the content of carbon, hydrogen, oxygen, nitrogen, sulphur, and chlorine on a dry ash free basis (daf) is presented. The proposed model was derived from 117 relevant organic substances which represent the main constituents in MSW with known standard entropies using statistical analysis. The substances were divided into different waste fractions; namely, food, wood/paper, textiles/rubber and plastics waste and the standard entropies of each waste fraction and for the complete mixture were calculated. The correlation of the standard entropy of the complete waste mixture derived was found to be somsw= 0.0101C + 0.0630H + 0.0106O + 0.0108N + 0.0155S + 0.0084Cl (kJ.K-1.kg) and the present correlation can be used for estimating the absolute entropy of MSW by using the elemental compositions of the fuel within the range of 10.3% ≤ C ≤ 95.1%, 0.0% ≤ H ≤ 14.3%, 0.0% ≤ O ≤ 71.1%, 0.0 ≤ N ≤ 66.7%, 0.0% ≤ S ≤ 42.1%, 0.0% ≤ Cl ≤ 89.7%. The model is also applicable for the efficient modelling of a combustion system in a waste-to-energy plant.
Abstract: Biogas can be currently considered as an alternative option for electricity production, mainly due to its high energy content (hydrocarbon-rich source), its renewable status and its relatively low utilization cost. Solid Oxide Fuel Cell (SOFC) stacks convert fuel’s chemical energy to electricity with high efficiencies and reveal significant advantages on fuel flexibility combined with lower emissions rate, especially when utilize biogas. Electricity production by biogas constitutes a composite problem which incorporates an extensive parametric analysis on numerous dynamic variables. The main scope of the presented study is to propose a detailed thermodynamic model on the optimization of SOFC-based power plants’ operation based on fundamental thermodynamics, energy and exergy balances. This model named THERMAS (THERmodynamic MAthematical Simulation model) incorporates each individual process, during electricity production, mathematically simulated for different case studies that represent real life operational conditions. Also, THERMAS offers the opportunity to choose a great variety of different values for each operational parameter individually, thus allowing for studies within unexplored and experimentally impossible operational ranges. Finally, THERMAS innovatively incorporates a specific criterion concluded by the extensive energy analysis to identify the most optimal scenario per simulated system in exergy terms. Therefore, several dynamical parameters as well as several biogas mixture compositions have been taken into account, to cover all the possible incidents. Towards the optimization process in terms of an innovative OPF (OPtimization Factor), presented here, this research study reveals that systems supplied by low methane fuels can be comparable to these supplied by pure methane. To conclude, such an innovative simulation model indicates a perspective on the optimal design of a SOFC stack based system, in the direction of the commercialization of systems utilizing biogas.
Abstract: TiO2 particles have been added in molten aluminium to result in aluminium based cast Al/Al3Ti-Al2O3 composite, which has been added then to molten magnesium to synthesize magnesium based cast Mg-Al/Al3Ti-Al2O3 composite. The nominal compositions in terms of Mg, Al, and TiO2 contents in the magnesium based composites are Mg-9Al-0.6TiO2, Mg-9Al-0.8TiO2, Mg-9Al-1.0TiO2 and Mg-9Al-1.2TiO2 designated respectively as MA6T, MA8T, MA10T and MA12T. The microstructure of the cast magnesium based composite shows grayish rods of intermetallics Al3Ti, inherited from aluminium based composite but these rods, on hot forging, breaks into smaller lengths decreasing the average aspect ratio (length to diameter) from 7.5 to 3.0. There are also cavities in between the broken segments of rods. β-phase in cast microstructure, Mg17Al12, dissolves during heating prior to forging and re-precipitates as relatively finer particles on cooling. The amount of β-phase also decreases on forging as segregation is removed. In both the cast and forged composite, the Brinell hardness increases rapidly with increasing addition of TiO2 but the hardness is higher in forged composites by about 80 BHN. With addition of higher level of TiO2 in magnesium based cast composite, yield strength decreases progressively but there is marginal increase in yield strength over that of the cast Mg-9 wt. pct. Al, designated as MA alloy. But the ultimate tensile strength (UTS) in the cast composites decreases with the increasing particle content indicating possibly an early initiation of crack in the brittle inter-dendritic region and their easy propagation through the interfaces of the particles. In forged composites, there is a significant improvement in both yield strength and UTS with increasing TiO2 addition and also, over those observed in their cast counterpart, but at higher addition it decreases. It may also be noted that as in forged MA alloy, incomplete recovery of forging strain increases the strength of the matrix in the composites and the ductility decreases both in the forged alloy and the composites. Initiation fracture toughness, JIC, decreases drastically in cast composites compared to that in MA alloy due to the presence of intermetallic Al3Ti and Al2O3 particles in the composite. There is drastic reduction of JIC on forging both in the alloy and the composites, possibly due to incomplete recovery of forging strain in both as well as breaking of Al3Ti rods and the voids between the broken segments of Al3Ti rods in composites. The ratio of tearing modulus to elastic modulus in cast composites show higher ratio, which increases with the increasing TiO2 addition. The ratio decreases comparatively more on forging of cast MA alloy than those in forged composites.
Abstract: The main cause of several neurodegenerative diseases such as Alzhemier, Parkinson and spongiform encephalopathies is formation of amyloid fibrils and plaques in proteins. We have analyzed different sets of proteins and peptides to understand the influence of sequence based features on protein aggregation process. The comparison of 373 pairs of homologous mesophilic and thermophilic proteins showed that aggregation prone regions (APRs) are present in both. But, the thermophilic protein monomers show greater ability to ‘stow away’ the APRs in their hydrophobic cores and protect them from solvent exposure. The comparison of amyloid forming and amorphous b-aggregating hexapeptides suggested distinct preferences for specific residues at the six positions as well as all possible combinations of nine residue pairs. The compositions of residues at different positions and residue pairs have been converted into energy potentials and utilized for distinguishing between amyloid forming and amorphous b-aggregating peptides. Our method could correctly identify the amyloid forming peptides at an accuracy of 95-100% in different datasets of peptides.
Abstract: The aim of this study is to evaluate the influence of raw material composition on the microstructure, mechanical and fatigue properties and micromechanisms of failure of nodular cast iron. In order to evaluate the influence of charge composition, the structural analysis, mechanical and fatigue tests and microfractographic analysis were carried out on specimens of ten melts with different charge compositions. The basic charge of individual melts was formed by different ratio of pig iron and steel scrap and by different additive for regulation of chemical composition (silicon carbide or ferrosilicon). The results show differences in mechanical and fatigue properties, which are connected with the microstructure. SiC additive positively influences microstructure. Consequently, mechanical and fatigue properties of nodular cast iron are improved, especially in the melts with higher ratio of steel scrap in the charge.
Abstract: Philip Morris International (PMI) is developing a range
of novel tobacco products with the potential to reduce individual
risk and population harm in comparison to smoking cigarettes.
One of these products is the Tobacco Heating System 2.2 (THS
2.2), (named as the Electrically Heated Tobacco System (EHTS) in
this paper), already commercialized in a number of countries (e.g.,
Japan, Italy, Switzerland, Russia, Portugal and Romania). During use,
the patented EHTS heats a specifically designed tobacco product
(Electrically Heated Tobacco Product (EHTP)) when inserted into
a Holder (heating device). The EHTP contains tobacco material in
the form of a porous plug that undergoes a controlled heating process
to release chemical compounds into vapors, from which an aerosol
is formed during cooling. The aim of this work was to investigate
the aerosol formation characteristics for realistic operating conditions
of the EHTS as well as for relevant gas mixture compositions
measured in the EHTP aerosol consisting mostly of water, glycerol
and nicotine, but also other compounds at much lower concentrations.
The nucleation process taking place in the EHTP during use when
operated in the Holder has therefore been modeled numerically using
an extended Classical Nucleation Theory (CNT) for multicomponent
gas mixtures. Results from the performed simulations demonstrate
that aerosol droplets are formed only in the presence of an aerosol
former being mainly glycerol. Minor compounds in the gas mixture
were not able to reach a supersaturated state alone and therefore
could not generate aerosol droplets from the multicomponent gas
mixture at the operating conditions simulated. For the analytically
characterized aerosol composition and estimated operating conditions
of the EHTS and EHTP, glycerol was shown to be the main aerosol
former triggering the nucleation process in the EHTP. This implies
that according to the CNT, an aerosol former, such as glycerol
needs to be present in the gas mixture for an aerosol to form
under the tested operating conditions. To assess if these conclusions
are sensitive to the initial amount of the minor compounds and to
include and represent the total mass of the aerosol collected during
the analytical aerosol characterization, simulations were carried out
with initial masses of the minor compounds increased by as much
as a factor of 500. Despite this extreme condition, no aerosol
droplets were generated when glycerol, nicotine and water were
treated as inert species and therefore not actively contributing to the
nucleation process. This implies that according to the CNT, an aerosol
cannot be generated without the help of an aerosol former, from
the multicomponent gas mixtures at the compositions and operating
conditions estimated for the EHTP, even if all minor compounds are
released or generated in a single puff.
Abstract: The identification of lipid and soluble sugar components in flour samples of different cultivars belonging to common oat species (Avena sativa L.) was performed: spring oat, winter oat and hulless oat. Fatty acids were extracted from flour samples with n-hexane, and derivatized into volatile methyl esters, using TMSH (trimethylsulfonium hydroxide in methanol). Soluble sugars were then extracted from defatted and dried samples of oat flour with 96% ethanol, and further derivatized into corresponding TMS-oximes, using hydroxylamine hydrochloride solution and BSTFA (N,O-bis-(trimethylsilyl)-trifluoroacetamide). The hexane and ethanol extracts of each oat cultivar were analyzed using GC-MS system. Lipid and simple sugar compositions are very similar in all samples of investigated cultivars. Chemometric tool was applied to numeric values of automatically integrated surface areas of detected lipid and simple sugar components in their corresponding derivatized forms. Hierarchical cluster analysis shows a very high similarity between the investigated flour samples of oat cultivars, according to the fatty acid content (0.9955). Moderate similarity was observed according to the content of soluble sugars (0.50). These preliminary results support the idea of establishing methods for oat flour authentication, and provide the means for distinguishing oat flour samples, regardless of the variety, from flour samples made of other cereal species, just by lipid and simple sugar profile analysis.
Abstract: Environment free of pollutants should be the concern of every individual but with industrialization and urbanization it is difficult to achieve. In view of achieving a pollution limited environment at low cost, a study was conducted on the use of bioremediation technology to remediate hydrocarbons and three heavy metals namely; copper (Cu), zinc (Zn) and iron (Fe) from a typical petroleum refinery wastewater in a closed system. Physicochemical and microbiological characteristics on the wastewater sample revealed that it was polluted with the aforementioned pollutants. Isolation and identification of microorganisms present in the wastewater sample revealed the presence of Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis. Bioremediation experiments carried out on five batch reactors with different compositions but at same environmental conditions revealed that treatment T5 (boosted with the association of Bacillus subtilis, Micrococcus luteus) gave the best result in terms of oil and grease content removal (i.e. 67% in 63 days). In addition, these microorganisms were able of reducing the concentrations of heavy metals in the sample. Treatments T5, T3 (boosted with Bacillus subtilis only) and T4 (boosted with Micrococcus luteus only) gave optimum percentage uptakes of 65, 75 and 25 for Cu, Zn and Fe respectively.
Abstract: We have incorporated the translational rotational (TR)
coupling effects in the framework of three body force shell model
(TSM) to develop an extended TSM (ETSM). The dynamical matrix
of ETSM has been applied to compute the phonon frequencies of
orientationally disordered mixed crystal (ND4Br)x(KBr)1-x in (q00),
(qq0) and (qqq) symmetry directions for compositions 0.10≤x≤0.50
at T=300K.These frequencies are plotted as a function of wave vector
k. An unusual acoustic mode softening is found along symmetry
directions (q00) and (qq0) as a result of translation-rotation coupling.
Abstract: The safflower seed contains about 25-40% solvent extract and 20-33% fiber. It is well known that dietary phospholipids lower serum cholesterol levels effectively. The nutrient composition of safflower seed changes depending on region, soil and genotypes. This research was made by using of six natural selected (A22, A29, A30, C12, E1, F4, G8, G12, J27) and three commercial (Remzibey, Dincer, Black Sun1) varieties of safflower genotypes. The research was conducted on field conditions for two years (2009 and 2010) in randomized complete block design with three replications in Konya-Turkey ecological conditions. Oil contents, mineral contents and their correlations were determined in the research. According to the results, oil content was ranged from 22.38% to 34.26%, while the minerals were in between the following values: 1469, 04-2068.07 mg kg-1 for Ca, 7.24-11.71 mg kg-1 for B, 13.29-17.41 mg kg-1 for Cu, 51.00-79.35 mg kg-1 for Fe, 3988-6638.34 mg kg-1 for K, 1418.61-2306.06 mg kg-1 for Mg, 11.37-17.76 mg kg-1 for Mn, 4172.33-7059.58 mg kg-1 for P and 32.60-59.00 mg kg-1 for Zn. Correlation analysis that was made separately for the commercial varieties and wild lines showed that high level of oil content was negatively affected by all the investigated minerals except for K and Zn in the commercial varieties.
Abstract: The tribological test with Pin-On-Disc configuration
measures friction and wear properties in dry or lubricated sliding
surfaces of a variety of materials and coatings. Polymeric matrix
composites loaded with mineral filler were used, 1%, 3%, 10%, 30%,
and 50% mass percentage of filler, to reduce the material cost by
using mineral tailings. Using a pin-on-disc tribometer to quantify
coefficient of friction and wear resistance of the specimens. The
parameters known to performing the test were 300 rpm rotation,
normal load of 16N and duration of 33.5 minutes. The composite
with 10% mineral filler performed better, considering that the wear
resistance was good when compared to the other compositions and an
average low coefficient of friction, in the order of μ ≤ 0.15.
Abstract: Recently developed cooperative diversity scheme
enables a terminal to get transmit diversity through the support of other
terminals. However, most of the introduced cooperative schemes have
a common fault of decreased transmission rate because the destination
should receive the decodable compositions of symbols from the source
and the relay. In order to achieve high data rate, we propose a
cooperative scheme that employs hierarchical modulation. This
scheme is free from the rate loss and allows seamless cooperative
communication.
Abstract: In language learning, second language learners as well
as Native speakers commit errors in their attempt to achieve
competence in the target language. The realm of collocation has to do
with meaning relation between lexical items. In all human language,
there is a kind of ‘natural order’ in which words are arranged or relate
to one another in sentences so much so that when a word occurs in a
given context, the related or naturally co-occurring word will
automatically come to the mind. It becomes an error, therefore, if
students inappropriately pair or arrange such ‘naturally’ co–occurring
lexical items in a text. It has been observed that most of the second
language learners in this research group commit collocation errors. A
study of this kind is very significant as it gives insight into the kinds
of errors committed by learners. This will help the language teacher
to be able to identify the sources and causes of such errors as well as
correct them thereby guiding, helping and leading the learners
towards achieving some level of competence in the language. The
aim of the study is to understand the nature of these errors as
stumbling blocks to effective essay writing. The objective of the
study is to identify the errors, analyze their structural compositions so
as to determine whether there are similarities between students in this
regard and to find out whether there are patterns to these kinds of
errors which will enable the researcher to understand their sources
and causes. As a descriptive research, the researcher samples some
nine hundred essays collected from three hundred undergraduate
learners of English as a second language in the Federal College of
Education, Kano, North- West Nigeria, i.e. three essays per each
student. The essays which were given on three different lecture times
were of similar thematic preoccupations (i.e. same topics) and length
(i.e. same number of words). The essays were written during the
lecture hour at three different lecture occasions. The errors were
identified in a systematic manner whereby errors so identified were
recorded only once even if they occur severally in students’ essays.
The data was collated using percentages in which the identified
numbers of occurrences were converted accordingly in percentages.
The findings from the study indicate that there are similarities as well
as regular and repeated errors which provided a pattern. Based on the
pattern identified, the conclusion is that students’ collocation errors
are attributable to poor teaching and learning which resulted in wrong
generalization of rules.
Abstract: Inspired by the Formula-1 competition, IMechE
(Institute of Mechanical Engineers) and Formula SAE (Society of
Mechanical Engineers) organize annual competitions for University
and College students worldwide to compete with a single-seat racecar
they have designed and built. Design of the chassis or the frame is a
key component of the competition because the weight and stiffness
properties are directly related with the performance of the car and the
safety of the driver. In addition, a reduced weight of the chassis has
direct influence on the design of other components in the car. Among
others, it improves the power to weight ratio and the aerodynamic
performance. As the power output of the engine or the battery
installed in the car is limited to 80 kW, increasing the power to
weight ratio demands reduction of the weight of the chassis, which
represents the major part of the weight of the car. In order to reduce
the weight of the car, ION Racing team from University of
Stavanger, Norway, opted for a monocoque design. To ensure
fulfilment of the competition requirements of the chassis, the
monocoque design should provide sufficient torsional stiffness and
absorb the impact energy in case of possible collision. The study reported in this article is based on the requirements for
Formula Student competition. As part of this study, diverse
mechanical tests were conducted to determine the mechanical
properties and performances of the monocoque design. Upon a
comprehensive theoretical study of the mechanical properties of
sandwich composite materials and the requirements of monocoque
design in the competition rules, diverse tests were conducted
including 3-point bending test, perimeter shear test and test for
absorbed energy. The test panels were homemade and prepared with
equivalent size of the side impact zone of the monocoque, i.e. 275
mm x 500 mm, so that the obtained results from the tests can be
representative. Different layups of the test panels with identical core
material and the same number of layers of carbon fibre were tested
and compared. Influence of the core material thickness was also
studied. Furthermore, analytical calculations and numerical analysis
were conducted to check compliance to the stated rules for Structural
Equivalency with steel grade SAE/AISI 1010. The test results were
also compared with calculated results with respect to bending and
torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition
and strength of the composite material selected for the monocoque
design has equivalent structural properties as a welded frame and thus
comply with the competition requirements. The developed analytical
calculation algorithms and relations will be useful for future
monocoque designs with different lay-ups and compositions.
Abstract: In this study, the effects and interactions of reaction
time and capping agent assistance during sol-gel synthesis of
magnesium substituted hydroxyapatite nanopowder (MgHA) on
hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) ratio, Ca/P
ratio and mean crystallite size was examined experimentally as well
as through statistical analysis. MgHA nanopowders were synthesized
by sol-gel technique at room temperature using aqueous solution of
calcium nitrate tetrahydrate, magnesium nitrate hexahydrate and
potassium dihydrogen phosphate as starting materials. The reaction
time for sol-gel synthesis was varied between 15 to 60 minutes. Two
process routes were followed with and without addition of
triethanolamine (TEA) in the solutions. The elemental compositions
of as-synthesized powders were determined using X-ray fluorescence
(XRF) spectroscopy. The functional groups present in the assynthesized
MgHA nanopowders were established through Fourier
Transform Infrared Spectroscopy (FTIR). The amounts of phases
present, Ca/P ratio and mean crystallite sizes of MgHA nanopowders
were determined using X-ray diffraction (XRD). The HA content in
biphasic mixture of HA and β-TCP and Ca/P ratio in as-synthesized
MgHA nanopowders increased effectively with reaction time of sols
(p0.15, two way ANOVA). The MgHA nanopowders
synthesized with TEA assistance exhibited 14 nm lower crystallite
size (p
Abstract: Within this paper, latest results on processing of energetic nanomaterials by means of the Spray Flash Evaporation technique are presented. This technology constitutes a highly effective and continuous way to prepare fascinating materials on the nano- and micro-scale. Within the process, a solution is set under high pressure and sprayed into an evacuated atomization chamber. Subsequent ultrafast evaporation of the solvent leads to an aerosol stream, which is separated by cyclones or filters. No drying gas is required, so the present technique should not be confused with spray dying. Resulting nanothermites, insensitive explosives or propellants and compositions are foreseen to replace toxic (according to REACH) and very sensitive matter in military and civil applications. Diverse examples are given in detail: nano-RDX (n-Cyclotrimethylentrinitramin) and nano-aluminum based systems, mixtures (n-RDX/n-TNT - trinitrotoluene) or even cocrystalline matter like n-CL-20/HMX (Hexanitrohexaazaisowurtzitane/ Cyclotetra-methylentetranitramin). These nanomaterials show reduced sensitivity by trend without losing effectiveness and performance. An analytical study for material characterization was performed by using Atomic Force Microscopy, X-Ray Diffraction, and combined techniques as well as spectroscopic methods. As a matter of course, sensitivity tests regarding electrostatic discharge, impact, and friction are provided.
Abstract: Rice Husk (RH) is the major byproduct in the
processing of paddy rice. The management of this waste has become
a big challenge to some of the rice producers, some of these wastes
are left in open dumps while some are burn in the open space, and
these two actions have been contributing to environmental pollution.
This study evaluates an alternative waste management of this
agricultural product for use as a civil engineering material. The RH
was burn in a controlled environment to form Rice Husk Ash (RHA).
The RHA was mix with lateritic clay at 0, 2, 4, 6, 8, and 10%
proportion by weight. Chemical test was conducted on the open burn
and controlled burn RHA with the lateritic clay. Physical test such as
particle size distribution, Atterberg limits test, and density test were
carried out on the mix material. The chemical composition obtained
for the RHA showed that the total percentage compositions of Fe2O3,
SiO2 and Al2O3 were found to be above 70% (class “F” pozzolan)
which qualifies it as a very good pozzolan. The coefficient of
uniformity (Cu) was 8 and coefficient of curvature (Cc) was 2 for the
soil sample. The Plasticity Index (PI) for the 0, 2, 4, 6, 8. 10% was
21.0, 18.8, 16.7, 14.4, 12.4 and 10.7 respectively. The work
concluded that RHA can be effectively used in hydraulic barriers and
as a stabilizing agent in soil stabilization.