Abstract: Textile industries cater to varied customer preferences and contribute substantially to the economy. However, these textile industries also produce a considerable amount of effluents. Prominent among these are the azo dyes which impart considerable color and toxicity even at low concentrations. Azo dyes are also used as coloring agents in food and pharmaceutical industry. Despite their applications, azo dyes are also notorious pollutants and carcinogens. Popular techniques like photo-degradation, biodegradation and the use of oxidizing agents are not applicable for all kinds of dyes, as most of them are stable to these techniques. Chemical coagulation produces a large amount of toxic sludge which is undesirable and is also ineffective towards a number of dyes. Most of the azo dyes are stable to UV-visible light irradiation and may even resist aerobic degradation. Adsorption has been the most preferred technique owing to its less cost, high capacity and process efficiency and the possibility of regenerating and recycling the adsorbent. Adsorption is also most preferred because it may produce high quality of the treated effluent and it is able to remove different kinds of dyes. However, the adsorption process is influenced by many variables whose inter-dependence makes it difficult to identify optimum conditions. The variables include stirring speed, temperature, initial concentration and adsorbent dosage. Further, the internal diffusional resistance inside the adsorbent particle leads to slow uptake of the solute within the adsorbent. Hence, it is necessary to identify optimum conditions that lead to high capacity and uptake rate of these pollutants. In this work, commercially available activated carbon was chosen as the adsorbent owing to its high surface area. A typical azo dye found in textile effluent waters, viz. the monoazo Acid Orange 10 dye (CAS: 1936-15-8) has been chosen as the representative pollutant. Adsorption studies were mainly focused at obtaining equilibrium and kinetic data for the batch adsorption process at different process conditions. Studies were conducted at different stirring speed, temperature, adsorbent dosage and initial dye concentration settings. The Full Factorial Design was the chosen statistical design framework for carrying out the experiments and identifying the important factors and their interactions. The optimum conditions identified from the experimental model were validated with actual experiments at the recommended settings. The equilibrium and kinetic data obtained were fitted to different models and the model parameters were estimated. This gives more details about the nature of adsorption taking place. Critical data required to design batch adsorption systems for removal of Acid Orange 10 dye and identification of factors that critically influence the separation efficiency are the key outcomes from this research.
Abstract: In this paper, a PSO based fractional order PID (FOPID) controller is proposed for concentration control of an isothermal Continuous Stirred Tank Reactor (CSTR) problem. CSTR is used to carry out chemical reactions in industries, which possesses complex nonlinear dynamic characteristics. Particle Swarm Optimization algorithm technique, which is an evolutionary optimization technique based on the movement and intelligence of swarm is proposed for tuning of the controller for this system. Comparisons of proposed controller with conventional and fuzzy based controller illustrate the superiority of proposed PSO-FOPID controller.
Abstract: This research work is an experimental study, through
development of an adhesive from Prosopis africana endosperm. The
prosopis seed for this work were obtained from Enugu State in the
South East part of Nigeria. The seeds were prepared by separating the
endosperm from the seed coat and cotyledon. Three methods were
used to separate them, which are acidic method, roasting method and
boiling method. 20g of seed were treated with different
concentrations (25, 40, 55, 70, and 85% w/w) at 100°C and constant
time (30 minutes), under continuous stirring with magnetic stirrer.
Also 20g of seed were treated with sulphuric acid of concentrations
40% w/w at 100°C with different time (10, 15, 20, 25, 30 minutes),
under continuous stirring with magnetic stirrer. Finally, 20g of seed
were treated with sulphuric acid of concentrations 40% w/w at
different temperature (20°C, 40°C, 60°C, 80°C, and 100°C) with
constant time (30 minutes), under continuous stirring with magnetic
stirrer. The whole endosperm extracted was adhesive. The physical
properties of the adhesive were determined (appearance, odour, taste,
solubility, pH, size, and binding strength). The percentage of the
adhesive yield makes the commercialization of the seed in Nigeria
possible and profitable. The very high viscosity attained at low
concentrations makes prosopis adhesive an excellent thickener in the
food industry.
Abstract: A Friction stir welding tool is a critical component to
the success of the process. The tool typically consists of a rotating
round shoulder and a threaded cylindrical pin that heats the work
piece, mostly by friction, and moves the softened alloy around it to
form the joint. In this research work, an attempt has been made to
investigate the relationship between FSW variables mainly tool
profile, rotating speed, welding speed and the mechanical properties
(tensile strength, yield strength, percentage elongation, and micro
hardness) of friction stir welded aluminum alloy 5083 joints. From
the experimental details, it can be assessed that the joint produced by
using Triflute profile tool has contribute superior mechanical and
structural properties as compared to Tapered unthreaded & Threaded
tool for 1000rpm.
Abstract: This paper presents a comparative analysis of
continuously stirred tank reactor (CSTR) control based on adaptive
control and optimal tuning of PID control based on particle swarm
optimization. In the design of adaptive control, Model reference
adaptive control (MRAC) scheme is used, in which the adaptation
law have been developed by MIT rule & Lyapunov’s rule. In PSO
control parameters of PID controller is tuned by using the concept of
particle swarm optimization to get optimized operating point for
minimum integral square error (ISE) condition. The results show the
adjustment of PID parameters converting into the optimal operating
point and the good control response can be obtained by the PSO
technique.
Abstract: In this study, the commercial finite element software
ABAQUS was used to develop a three-dimensional nonlinear finite
element model capable of simulating the pull-out test of reinforcing
bars from underwater concrete. The results of thirty-two pull-out tests
that have different parameters were implemented in the software to
study the effect of the concrete cover, the bar size, the use of stirrups,
and the compressive strength of concrete. The interaction properties used in the model provided accurate
results in comparison with the experimental bond-slip results, thus
the model has successfully simulated the pull-out test. The results of
the finite element model are used to better understand and visualize
the distribution of stresses in each component of the model, and to
study the effect of the various parameters used in this study including
the role of the stirrups in preventing the stress from reaching to the
sides of the specimens.
Abstract: Friction stir welding and tungsten inert gas welding
techniques were employed to weld armor grade aluminum alloy to
investigate the effect of welding processes on tensile behavior of
weld joints. Tensile tests, Vicker microhardness tests and optical
microscopy were performed on developed weld joints and base metal.
Welding process influenced tensile behavior and microstructure of
weld joints. Friction stir welded joints showed tensile behavior better
than tungsten inert gas weld joints.
Abstract: This paper reports the viability of developing Zn-27Al
alloy matrix hybrid composites reinforced with alumina, graphite and
fly ash (solid waste bye product of coal in thermal power plants).
This research work was aimed at developing low cost-high
performance Zn-27Al matrix composite with low density. Alumina
particulates (Al2O3), graphite added with 0, 2, 3, 4 and 5 wt% fly ash
were utilized to prepare 10wt% reinforcing phase with Zn-27Al alloy
as matrix using two-step stir casting method. Density measurement,
estimated percentage porosity, tensile testing, micro hardness
measurement and optical microscopy were used to assess the
performance of the composites produced. The results show that the
hardness, ultimate tensile strength, and percent elongation of the
hybrid composites decrease with increase in fly ash content. The
maximum decrease in hardness and ultimate tensile strength of
13.72% and 15.25% respectively were observed for composite grade
containing 5wt% fly ash. The percentage elongation of composite
sample without fly ash is 8.9% which is comparable with that of the
sample containing 2wt% fly ash with percentage elongation of 8.8%.
The fracture toughness of the fly ash containing composites was
however superior to those of composites without fly ash with 5wt%
fly ash containing composite exhibiting the highest fracture
toughness. The results show that fly ash can be utilized as
complementary reinforcement in ZA-27 alloy matrix composite to
reduce cost.
Abstract: As a by-product of the biodiesel industries, glycerol
has been vastly generated which surpasses the market demand. It is
imperative to develop an efficient glycerol valorization processes in
minimizing the net energy requirement and intensifying the biodiesel
production. In this study, base-catalyzed transesterification of
glycerol with dimethyl carbonate using microwave irradiation as
heating method to produce glycerol carbonate was conducted by
varying grades of glycerol, i.e. 70%, 86% and 99% purity, that is
obtained from biodiesel plant. Metal oxide catalysts were used with
varying operating parameters including reaction time, DMC/glycerol
molar ratio, catalyst weight %, temperature and stirring speed. From
the study on the effect of different operating parameters it was found
that the type of catalyst used has the most significant effect on the
transesterification reaction. Amidst the metal oxide catalysts
examined, CaO gave the best performance. This study indicates the
feasibility of producing glycerol carbonate using different grade of
glycerol in both conventional thermal activation and microwave
irradiation with CaO as catalyst. Microwave assisted
transesterification (MAT) of glycerol into glycerol carbonate has
demonstrated itself as an energy efficient route by achieving 94.2%
yield of GC at 65°C, 5 minutes reaction time, 1 wt% CaO and
DMC/glycerol molar ratio of 2. The advantages of MAT
transesterification route has made the direct utilization of bioglycerol
from biodiesel production without the need of purification. This has
marked a more economical and less-energy intensive glycerol
carbonate synthesis route.
Abstract: It is the patient compliance and stability in
combination with controlled drug delivery and biocompatibility that
forms the core feature in present research and development of
sustained biodegradable patch formulation intended for wound
healing. The aim was to impart sustained degradation, sterile
formulation, significant folding endurance, elasticity,
biodegradability, bio-acceptability and strength. The optimized
formulation comprised of polymers including Hydroxypropyl methyl
cellulose, Ethylcellulose, and Gelatin, and Citric Acid PEG Citric
acid (CPEGC) triblock dendrimers and active Curcumin. Polymeric
mixture dissolved in geometric order in suitable medium through
continuous stirring under ambient conditions. With continued stirring
Curcumin was added with aid of DCM and Methanol in optimized
ratio to get homogenous dispersion. The dispersion was sonicated
with optimum frequency and for given time and later casted to form a
patch form. All steps were carried out under strict aseptic conditions.
The formulations obtained in the acceptable working range were
decided based on thickness, uniformity of drug content, smooth
texture and flexibility and brittleness. The patch kept on stability
using butter paper in sterile pack displayed folding endurance in
range of 20 to 23 times without any evidence of crack in an
optimized formulation at room temperature (RT) (24 ± 2°C). The
patch displayed acceptable parameters after stability study conducted
in refrigerated conditions (8±0.2°C) and at RT (24 ± 2°C) up to 90
days. Further, no significant changes were observed in critical
parameters such as elasticity, biodegradability, drug release and drug
content during stability study conducted at RT 24±2°C for 45 and 90
days. The drug content was in range 95 to 102%, moisture content
didn’t exceeded 19.2% and patch passed the content uniformity test.
Percentage cumulative drug release was found to be 80% in 12h and
matched the biodegradation rate as drug release with correlation
factor R2>0.9. The biodegradable patch based formulation developed
shows promising results in terms of stability and release profiles.
Abstract: Numerical investigations were conducted to study the
influence of flexural reinforcement ratio on the diagonal cracking
strength and ultimate shear strength of reinforced concrete (RC)
beams without stirrups. Three-dimensional nonlinear finite element
analyses (FEAs) of the beams with flexural reinforcement ratios
ranging from 0.58% to 2.20% subjected to a mid-span concentrated
load were carried out. It is observed that the load-deflection and loadstrain
curves obtained from the numerical analyses agree with those
obtained from the experiments. It is concluded that flexural
reinforcement ratio has a significant effect on the shear strength and
deflection capacity of RC beams without stirrups. The predictions of
diagonal cracking strength and ultimate shear strength of beams
obtained by using the equations defined by a number of codes and
researchers are compared with each other and with the experimental
values.
Abstract: Aluminium matrix composites with alumina
reinforcements give superior mechanical & physical properties. Their
applications in several fields like automobile, aerospace, defense,
sports, electronics, bio-medical and other industrial purposes are
becoming essential for the last several decades. In the present work,
fabrication of hybrid composite was done by Stir casting technique
using Al 6061 as a matrix with alumina and silicon carbide (SiC) as
reinforcement materials. The weight percentage of alumina is varied
from 2 to 4% and the silicon carbide weight percentage is maintained
constant at 2%. Hardness and wear tests are performed in the as cast
and heat treated conditions. Age hardening treatment was performed
on the specimen with solutionizing at 550°C, aging at two
temperatures (150 and 200°C) for different time durations. Hardness
distribution curves are drawn and peak hardness values are recorded.
Hardness increase was very sensitive with respect to the decrease in
aging temperature. There was an improvement in wear resistance of
the peak aged material when aged at lower temperature. Also
increase in weight percent of alumina, increases wear resistance at
lower temperature but opposite behavior was seen when aged at
higher temperature.
Abstract: Al6061 alloy base matrix, reinforced with particles of
silicon carbide (10 wt %) and Graphite powder (1wt%), known as
hybrid composites have been fabricated by liquid metallurgy route
(stir casting technique) and optimized at different parameters like
applied load, sliding speed and sliding distance by taguchi method. A
plan of experiment generated through taguchi technique was used to
perform experiments based on L27 orthogonal array. The developed
ANOVA and regression equations are used to find the optimum
coefficient of friction and wear under the influence of applied load,
sliding speed and sliding distance. On the basis of “smaller the best”
the dry sliding wear resistance was analysed and finally confirmation
tests were carried out to verify the experimental results.
Abstract: To understand the friction stir welding process, it is
very important to know the nature of the material flow in and around
the tool. The process is a combination of both thermal as well as
mechanical work i.e. it is a coupled thermo-mechanical process.
Numerical simulations are very much essential in order to obtain a
complete knowledge of the process as well as the physics underlying
it. In the present work a model based approach is adopted in order to
study material flow. A thermo-mechanical based CFD model is
developed using a Finite Element package, Comsol Multiphysics.
The fluid flow analysis is done. The model simultaneously predicts
shear strain fields, shear strain rates and shear stress over the entire
workpiece for the given conditions. The flow fields generated by the
streamline plot give an idea of the material flow. The variation of
dynamic viscosity, velocity field and shear strain fields with various
welding parameters is studied. Finally the result obtained from the
above mentioned conditions is discussed elaborately and concluded.
Abstract: Ulexite (Na2O.2CaO.5B2O3.16H2O) is boron mineral
that is found in large quantities in the Turkey and world. In this
study, the dissolution of this mineral in the disodium hydrogen
phosphate solutions has been studied. Temperature, concentration,
stirring speed, solid liquid ratio and particle size were selected as
parameters. The experimental results were successfully correlated by
linear regression using Statistica program. Dissolution curves were
evaluated shrinking core models for solid-fluid systems. It was
observed that increase in the reaction temperature and decrease in the
solid/liquid ratio causes an increase the dissolution rate of ulexite.
The activation energy was found to be 63.4 kJ/mol. The leaching of
ulexite was controlled by chemical reaction.
Abstract: Gypsum (CaSO4.2H2O) is a mineral that is found in
large quantities in the Turkey and in the World. In this study, the
dissolution of this mineral in the diammonium hydrogen phosphate
solutions has been studied. The dissolution and dissolution kinetics of
gypsum in diammonium hydrogen phosphate solutions will be useful
for evaluating of solid wastes containing gypsum. Parameters such as
diammonium hydrogen phosphate concentration, temperature and
stirring speed affecting on the dissolution rate of the gypsum in
diammonium hydrogen phosphate solutions were investigated. In
experimental studies have researched effectiveness of the selected
parameters. The dissolution of gypsum were examined in two parts at
low and high temperatures. The experimental results were
successfully correlated by linear regression using Statistica program.
Dissolution curves were evaluated shrinking core models for solidfluid
systems. The activation energy was found to be 34.58 kJ/mol
and 44.45 kJ/mol for the low and the high temperatures. The
dissolution of gypsum was controlled by chemical reaction both low
temperatures and high temperatures.
Abstract: Today, the pollution due to non-degradable material
such as plastics, has led to studies about the development of
environmental-friendly material. Because of biodegradability
obtained from natural sources, polylactid acid (PLA) and ijuk fiber
are interesting to modify into a composite. This material is also
expected to reduce the impact of environmental pollution. Surface
modification of ijuk fiber through alkalinization with 0.25 M NaOH
solution for 30 minutes was aimed to enhance its compatibility to
PLA, in order to improve properties of the composite such as the
mechanical properties. Alkalinization of the ijuk fibers annihilates
some surface components such as lignin, wax and hemicelloluse, so
the pore on the surface clearly appeared, decreasing of the density
and diameter of the ijuk fibers. The change of the ijuk fiber properties
leads to increase the mechanical properties of PLA composites
reinforced the ijuk fibers through strengthening of the mechanical
interlocking with the PLA matrix. An addition to enhance the
distribution of the fibers in the PLA matrix, the stirring during DCM
solvent evaporation from the mixture of the ijuk fibers and the
dissolved-PLA can reduce amount of the trapped-voids and fibers
pull-out phenomena, which can decrease the mechanical properties of
the composite.
Abstract: Geometric and mechanical properties all influence the
resistance of RC structures and may, in certain combination of
property values, increase the risk of a brittle failure of the whole
system.
This paper presents a statistical and probabilistic investigation on
the resistance of RC beams designed according to Eurocodes 2 and 8,
and subjected to multiple failure modes, under both the natural
variation of material properties and the uncertainty associated with
cross-section and transverse reinforcement geometry. A full
probabilistic model based on JCSS Probabilistic Model Code is
derived. Different beams are studied through material nonlinear
analysis via Monte Carlo simulations. The resistance model is
consistent with Eurocode 2. Both a multivariate statistical evaluation
and the data clustering analysis of outcomes are then performed.
Results show that the ultimate load behaviour of RC beams
subjected to flexural and shear failure modes seems to be mainly
influenced by the combination of the mechanical properties of both
longitudinal reinforcement and stirrups, and the tensile strength of
concrete, of which the latter appears to affect the overall response of
the system in a nonlinear way. The model uncertainty of the
resistance model used in the analysis plays undoubtedly an important
role in interpreting results.
Abstract: The computational fluid dynamics (CFD) study of
stirred tank with the air-water interface are carried out in the presence
of different types of the impeller and with or without baffles. A
multiple reference frame (MRF) approach with the volume of fluid
(VOF) method is used to capture the air-water interface. The RANS
(Reynolds Averaged Navier-Stokes) equations with k-ε turbulence
model are solved to predict the flow behavior of water and air phase
which are treated as a different phases. The predicted results have
shown that the VOF method is able to capture the interface in the
unbaffled tank. While, the VOF method is showing an unfeasible
results in the baffled tank with high rotational impeller speed. For
continuous stirred tank, the air-water interface is disturbed by the
inflow and the level of water is also increased with time.
Abstract: Brown seaweeds are abundant in Portuguese coastline
and represent an almost unexploited marine economic resource. One
of the most common species, easily available for harvesting in the
northwest coast, is Saccorhiza polyschides grows in the lowest shore
and costal rocky reefs. It is almost exclusively used by local farmers
as natural fertilizer, but contains a substantial amount of valuable
compounds, particularly alginates, natural biopolymers of high
interest for many industrial applications.
Alginates are natural polysaccharides present in cell walls of
brown seaweed, highly biocompatible, with particular properties that
make them of high interest for the food, biotechnology, cosmetics
and pharmaceutical industries. Conventional extraction processes are
based on thermal treatment. They are lengthy and consume high
amounts of energy and solvents. In recent years, microwave-assisted
extraction (MAE) has shown enormous potential to overcome major
drawbacks that outcome from conventional plant material extraction
(thermal and/or solvent based) techniques, being also successfully
applied to the extraction of agar, fucoidans and alginates. In the
present study, acid pretreatment of brown seaweed Saccorhiza
polyschides for subsequent microwave-assisted extraction (MAE) of
alginate was optimized. Seaweeds were collected in Northwest
Portuguese coastal waters of the Atlantic Ocean between May and
August, 2014. Experimental design was used to assess the effect of
temperature and acid pretreatment time in alginate extraction.
Response surface methodology allowed the determination of the
optimum MAE conditions: 40 mL of HCl 0.1 M per g of dried
seaweed with constant stirring at 20ºC during 14h. Optimal acid
pretreatment conditions have enhanced significantly MAE of
alginates from Saccorhiza polyschides, thus contributing for the
development of a viable, more environmental friendly alternative to
conventional processes.