Abstract: Household waste form a larger proportion of waste
generated across the state, accumulation of organic waste is an
apparent problem and the existing dump sites could be overstress.
Niger state has abundant arable land and water resources thus should
be one of the highest producers of agricultural crops in the country.
However, the major challenge to agricultural sector today is loss of
soil nutrient coupled with high cost of fertilizer. These have
continued to increase the use of fertilizer and decomposed solid waste
for enhance agricultural yield, which have varying effects on the soil
as well a threat to human livelihood. Consequently, vegetable yield
samples from poultry droppings, decomposed household waste
manure, NPK treatments and control from each replication were
subjected to proximate analysis to determine the nutritional and antinutritional
component as well as heavy metal concentration. Data
collected was analyzed using SPSS software and Randomized
complete Block Design means were compared. The result shows that
the treatments do not devoid the concentrations of any nutritional
components while the anti-nutritional analysis proved that NPK had
higher oxalate content than control and organic treats. The
concentration of lead and cadmium are within safe permissible level
while the mercury level exceeded the FAO/WHO maximum
permissible limit for the entire treatments depicts the need for urgent
intervention to minimize mercury levels in soil and manure in order
to mitigate its toxic effect. Thus, eco-agriculture should be widely
accepted and promoted by the stakeholders for soil amendment,
higher yield, strategies for sustainable environmental protection, food
security, poverty eradication, attainment of sustainable development
and healthy livelihood.
Abstract: This study focuses on the hydro-geology and chemical
constituents analysis of Ikogosi Warm Spring waters in South West
Nigeria. Ikogosi warm spring is a global tourist attraction because it
has both warm and cold spring sources. Water samples from the cold
spring, warm spring and the meeting point were collected, analyzed
and the result shows close similarity in temperature, hydrogen iron
concentration (pH), alkalinity, hardness, Calcium, Magnesium,
Sodium, Iron, total dissolved solid and heavy metals. The measured
parameters in the water samples are within World Health
Organisation standards for fresh water. The study of the geology of
the warm spring reveals that the study area is underlain by a group of
slightly migmatised to non-migmatised paraschists and meta-igneous
rocks. Also, concentration levels of selected heavy metals, (Copper,
Cadmium, Zinc, Arsenic and Cromium) were determined in the water
(ppm) samples. Chromium had the highest concentration value of
1.52ppm (an average of 49.67%) and Cadmium had the lowest
concentration with value of 0.15ppm (an average of 4.89%).
Comparison of these results showed that, their mean levels are within
the standard values obtained in Nigeria. It can be concluded that both
warm and spring water are safe for drinking.
Abstract: The ferrites ZnFe2O4, CdFe2O4 and CuFe2O4 are
synthesized in laboratory conditions using ceramic technology. Their
homogeneity and structure are proven by X-Ray diffraction analysis
and Mössbauer spectroscopy. The synthesized ferrites are subjected
to strong acid and high temperature leaching with solutions of H2SO4,
HCl and HNO3. The results indicate that the highest degree of
leaching of Zn, Cd and Cu from the ferrites is achieved by use of
HCl. The charging of five zinc sulfide concentrates was optimized using
the criterion of minimal amount of zinc ferrite produced when
roasting the concentrates in a fluidized bed. The results obtained are
interpreted in terms of the hydrometallurgical zinc production and
maximum recovery of zinc, copper and cadmium from initial zinc
concentrates after their roasting.
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: A problem of complex mineral resources development is urgent and priority, it is aimed at realization of the processes of their ecologically safe development, one of its components is revealing the influence of the forms of element compounds in raw materials and in the processing products. In view of depletion of the precious metal reserves at the traditional deposits in the XXI century the large-size open cast deposits, localized in black shale strata begin to play the leading role. Carbonaceous (black) shales carry a heightened metallogenic potential. Black shales with high content of carbon are widely distributed within the scope of Bureinsky massif. According to academician Hanchuk`s data black shales of Sutirskaya series contain generally PGEs native form. The presence of high absorptive towards carbonaceous matter gold and PGEs compounds in crude ore results in decrease of valuable components extraction because of their sorption into dissipated carbonaceous matter.
Abstract: The effects of wood ash from five common tropical
woods on the ignition point of four common tropical woods in
Nigeria were investigated. The ash and moisture contents of the wood
sawdust from Mahogany (Khaya ivorensis), Opepe (Sarcocephalus
latifolius), Abura (Mitragyna ciliata), Rubber (Heavea brasilensis)
and Poroporo (Sorghum bicolour) used, were determined using a
furnace (Vecstar furnaces, model ECF2, serial no. f3077) and oven
(Genlab laboratory oven, model MINO/040) respectively. The metal
contents of the five wood sawdust ash samples were determined
using a Perkin Elmer optima 3000 dv atomic absorption spectrometer
while the ignition points were determined using Vecstar furnaces
model ECF2. Poroporo had the highest ash content, 2.263g while
rubber had the least, 0.710g. The results for the moisture content
range from 2.971g to 0.903g. Magnesium metal had the highest
concentration of all the metals, in all the wood ash samples; with
mahogany ash having the highest concentration, 9.196ppm while
rubber ash had the least concentration of magnesium metal, 2.196
ppm. The ignition point results showed that the wood ashes from
mahogany and opepe increased the ignition points of the test wood
samples, Danta (Nesogordonia papaverifera), Ekpaya, Akomu
(Pycnanthus angolensis) and Oleku when coated on them while the
ashes from poroporo, rubber and abura decreased the ignition points
of the test wood samples when coated on them. However, Opepe saw
dust ash decreased the ignition point in one of the test wood samples,
suggesting that the metal content of the test wood sample was more
than that of the Opepe saw dust ash. Therefore, Mahogany and Opepe
saw dust ashes could be used in the surface treatment of wood to
enhance their fire resistance or retardancy. However, the caution to
be exercised in this application is that the metal content of the test
wood samples should be evaluated as well.
Abstract: Ceramic obtained on the base of aluminum oxide has
wide application range, because it has unique properties, for example,
wear-resistance, dielectric characteristics, and exploitation ability at
high temperatures and in corrosive atmosphere. Low temperature
synthesis of α-Al2O3 is energo-economical process and it is topical
for developing technologies of corundum ceramics fabrication. In the present work possibilities of low temperature transformation
of oxyhydroxides in α-Al2O3, during the presence of small amount of
rare–earth elements compounds (also Th, Re), have been discussed.
Aluminum unstable oxyhydroxides have been obtained by hydrolysis
of aluminium isopropoxide, nitrates, sulphate, and chloride in
alkaline environment at 80-90ºC temperatures. β-Al(OH)3 has been
received from aluminum powder by ultrasonic development. Drying
of oxyhydroxide sol has been conducted with presence of various
types seeds, which amount reaches 0,1-0,2% (mas). Neodymium,
holmium, thorium, lanthanum, cerium, gadolinium, disprosium
nitrates and rhenium carbonyls have been used as seeds and they
have been added to the sol specimens in amount of 0.1-0.2% (mas)
calculated on metals. Annealing of obtained gels is carried out at 70–
1100ºC for 2 hrs. The same specimen transforms in α-Al2O3 at
1100ºC. At this temperature in case of presence of lanthanum and
gadolinium transformation takes place by 70-85%. In case of
presence of thorium stabilization of γ-and θ-phases takes place. It is
established, that thorium causes inhibition of α-phase generation at
1100ºC, and at the time when in all other doped specimens α-phase is
generated at lower temperatures (1000-1050ºC). Synthesis of various
type compounds and simultaneous consolidation has developed in the
furnace of OXY-GON. Composite materials containing oxide and
non-oxide components close to theoretical data have been obtained in
this furnace respectively. During the work the following devices have
been used: X-ray diffractometer DRON-3M (Cu-Kα, Ni filter,
2º/min), High temperature vacuum furnace OXY-GON, electronic
scanning microscopes Nikon ECLIPSE LV 150, NMM-800TRF,
planetary mill Pulverisette 7 premium line, SHIMADZU Dynamic
Ultra Micro Hardness Tester, DUH-211S, Analysette 12 Dyna sizer.
Abstract: During welding or flame cutting of metals, the
prediction of heat affected zone (HAZ) is critical. There is need to
develop a simple mathematical model to calculate the temperature
variation in HAZ and derivative analysis can be used for this purpose.
This study presents analytical solution for heat transfer through
conduction in mild steel plate. The homogeneous and nonhomogeneous
boundary conditions are single variables. The full field
analytical solutions of temperature measurement, subjected to local
heating source, are derived first by method of separation of variables
followed with the experimental visualization using infrared imaging.
Based on the present work, it is suggested that appropriate heat input
characteristics controls the temperature distribution in and around
HAZ.
Abstract: Wire Electric Discharge Machining (WEDM) is
thermal machining process capable of machining very hard
electrically conductive material irrespective of their hardness.
WEDM is being widely used to machine micro scale parts with the
high dimensional accuracy and surface finish. The objective of this
paper is to optimize the process parameters of wire EDM to fabricate
the micro channels and to calculate the surface finish and material
removal rate of micro channels fabricated using wire EDM. The
material used is aluminum 6061 alloy. The experiments were
performed using CNC wire cut electric discharge machine. The effect
of various parameters of WEDM like pulse on time (TON) with the
levels (100, 150, 200), pulse off time (TOFF) with the levels (25, 35,
45) and current (IP) with the levels (105, 110, 115) were investigated
to study the effect on output parameter i.e. Surface Roughness and
Material Removal Rate (MRR). Each experiment was conducted
under different conditions of pulse on time, pulse off time and peak
current. For material removal rate, TON and Ip
were the most significant process parameter. MRR increases with the increase in
TON and Ip and decreases with the increase in TOFF. For surface
roughness, TON and Ip have the maximum effect and TOFF was found
out to be less effective.
Abstract: Oxygen Reduction Reaction (ORR) performance of
iron and nitrogen co-doped porous carbon nanoparticles (Fe-NPC)
with various physical and (electro) chemical properties have been
investigated. Fe-NPC nanoparticles are synthesized via a facile
soft-templating procedure by using Iron (III) chloride hexa-hydrate as
iron precursor and aminophenol-formaldehyde resin as both carbon
and nitrogen precursor. Fe-NPC nanoparticles shows high surface area
(443.83 m2g-1), high pore volume (0.52 m3g-1), narrow mesopore size
distribution (ca. 3.8 nm), high conductivity (IG/ID=1.04), high kinetic
limiting current (11.71 mAcm-2) and more positive onset potential
(-0.106 V) compared to metal-free NPC nanoparticles (-0.295V)
which make it high efficient ORR metal-free catalysts in alkaline
solution. This study may pave the way of feasibly designing iron and
nitrogen containing carbon materials (Fe-N-C) for highly efficient
oxygen reduction electro-catalysis.
Abstract: Groundwater is vital to the livelihoods and health of the majority of the people, since it provides almost the entire water resource for domestic, agricultural and industrial uses. Groundwater quality comprises the physical, chemical and bacteriological qualities. The present investigation was carried out to determine the physicochemical and bacteriological quality of the ground water sources in the residential areas of Karakulam Grama Panchayath in Thiruvananthapuram district, Kerala state in India. Karakulam is located in the eastern suburbs of Thiruvananthapuram city. The major drinking water source of the residents in the study area is wells. The present study aims to assess the portability and irrigational suitability of groundwater in the study area. The water samples were collected from randomly selected dug wells and bore wells in the study area during post monsoon and pre monsoon seasons of the year 2014 after a preliminary field survey. The physical, chemical and bacteriological parameters of the water samples were analyzed following standard procedures. The concentration of heavy metals (Cd, Pb and Mn) in the acid digested water samples were determined by using an Atomic Absorption Spectrophotometer. The results showed that the pH of well water samples ranged from acidic to alkaline level. In majority of well water samples (>54 %) the iron and magnesium content were found high in both the seasons studied, and the values were above the permissible limits of WHO drinking water quality standards. Bacteriological analyses showed that 63% of the wells were contaminated with total coliforms in both the seasons studied. Irrigational suitability of groundwater was assessed by determining the chemical indices like Sodium Percentage (%Na), Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Permeability Index (PI), and the results indicate that the well water in the study area are good for irrigation purposes. Therefore, the study reveals the degradation of drinking water quality groundwater sources in Karakulam Grama Panchayath in Thiruvananthapuram District, Keralain terms of its chemical and bacteriological characteristics, and is not potable without proper treatment. In the study, more than 1/3rdof the well water samples tested were positive for total coliforms, and the bacterial contamination may pose threat to public health. The study recommends the need for periodic well water quality monitoring in the study area and to conduct awareness programs among the residents.
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: A new design of aerostatic thrust bearing is proposed
for high static stiffness. The bearing body, which is mead of polymer
covered with metallic membrane, is held by a circular ring. Such a
support helps form a concave air gap to grasp the air pressure. The
polymer body, which can be made rapidly by either injection or
molding is able to provide extra damping under dynamic loading. The
smooth membrane not only serves as the bearing surface but also
protects the polymer body. The restrictor is a capillary inside a silicone
tube. It can passively compensate the variation of load by expanding
the capillary diameter for more air flux. In the present example, the
stiffness soars from 15.85 N/μm of typical bearing to 349.85 N/μm at
bearing elevation 9.5 μm; meanwhile the load capacity also enhances
from 346.86 N to 704.18 N.
Abstract: Cadmium (II) (Cd) is one of the major toxic elemental
pollutants, which is hazardous for humans, animals and plants. γ-
Polyglutamic acid (γ-PGA) is an extracellular biopolymer produced
by several species of Bacillus which has been reported to be an
effective biosorbent for metal ions. The effect of γ-PGA on growth of
rice grown under laboratory conditions was investigated. Rice seeds
were germinated and then grown at 30±1°C on filter paper soaked
with Cd solution and γ-PGA for 7 days. The result showed that Cd
significantly inhibited the growth of roots, shoots by reducing root,
and shoot lengths. Fresh and dry weights also decreased compared
with control; however, the addition of 500 mg·L-1 γ-PGA alleviated
rice seedlings from the adverse effects of Cd. The analysis of
physiological traits revealed that Cd caused a decrease in the total
chlorophyll and soluble protein contents and amylase activities in all
treatments. The Cd content in seedling tissues increased for the Cd
250 μM treatment (P
Abstract: In recent years, the use of the aluminum based alloys
in the industry and technology are increasing. Alloying elements in
aluminum have further been improving the strength and stiffness
properties that provide superior compared to other metals. In this
study, investigation of physical properties (microstructure,
microhardness, tensile strength, electrical conductivity and thermal
properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were
investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The
samples were directionally solidified upwards with different growth
rate V (8.3−165.45 μm/s) at constant temperature gradient G (7.73
K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile
strength (σ), electrical resistivity (ρ) and thermal properties (H, Cp,
Tm) of the samples were measured. Influence of the growth rate and
spacings on microhardness, ultimate tensile strength and electrical
resistivity were investigated and relationships between them were
obtained. According to results, λ values decrease with increasing V,
but HV, σ and ρ values increase with increasing V. Variations of
electrical resistivity (ρ) of solidified samples were also measured.
The enthalpy of fusion (H) and specific heat (Cp) for the alloy was
also determined by differential scanning calorimeter (DSC) from
heating trace during the transformation from liquid to solid. The
results in this work were compared with the previous similar
experimental results.
Abstract: This paper presents the influences on the entrainment
of serpentines by grinding and reagents during copper–nickel sulfide
flotation. The previous bench flotation tests were performed to extract
the metallic values from the ore in Yunnan Mine, China and the
relatively satisfied results with recoveries of 86.92% Cu, 54.92% Ni,
and 74.73% Pt+Pd in the concentrate were harvested at their grades of
4.02%, 3.24% and 76.61 g/t, respectively. However, the content of
MgO in the concentrate was still more than 19%. Micro-flotation tests
were conducted with the objective of figuring out the influences on the
entrainment of serpentines into the concentrate by particle size,
flocculants or depressants and collectors, as well as visual
observations in suspension by OLYMPUS camera. All the tests results
pointed to the presences of both “entrapped-in” serpentines and its
coating on the hydrophobic flocs resulted from strong collectors
(combination of butyl xanthate, butyl ammonium dithophosphate,
even after adding carboxymethyl cellulose as effective depressant.
And fine grinding may escalate the entrainment of serpentines in the
concentrate.
Abstract: In this work, the plastic behaviour of cold-rolled zinc
coated dual-phase steel sheets DP600 and DP800 grades is firstly
investigated with the help of uniaxial, hydraulic bulge and Forming
Limit Curve (FLC) tests. The uniaxial tensile tests were performed in
three angular orientations with respect to the rolling direction to
evaluate the strain-hardening and plastic anisotropy. True stressstrain
curves at large strains were determined from hydraulic bulge
testing and fitted to a work-hardening equation. The limit strains are
defined at both localized necking and fracture conditions according to
Nakajima’s hemispherical punch procedure. Also, an elasto-plastic
localization model is proposed in order to predict strain and stress
based forming limit curves. The investigated dual-phase sheets
showed a good formability in the biaxial stretching and drawing FLC
regions. For both DP600 and DP800 sheets, the corresponding
numerical predictions overestimated and underestimated the
experimental limit strains in the biaxial stretching and drawing FLC
regions, respectively. This can be attributed to the restricted failure
necking condition adopted in the numerical model, which is not
suitable to describe the tensile and shear fracture mechanisms in
advanced high strength steels under equibiaxial and biaxial stretching
conditions.
Abstract: The nickel-manganese (Ni-Mn) alloy coating prepared
from DC electrodeposition process in sulphamate bath was studied.
The effects of process parameters, such as current density and
electrolyte composition, on the cathodic current efficiency,
microstructure, internal stress and mechanical properties were
investigated. Because of its crucial effect on the application to the
electroforming of microelectronic components, the development of
low internal stress coating with high leveling power was emphasized.
It was found that both the coating’s manganese content and the
cathodic current efficiency increased with the raise in current density.
In addition, the internal stress of the deposited coating showed
compressive nature at low current densities while changed to tensile
one at higher current densities. Moreover, the metallographic
observation, X-ray diffraction measurement, and polarization curve
measurement were conducted. It was found that the Ni-Mn coating
consisted of nano-sized columnar grains and the maximum hardness of
the coating was associated with (111) preferred orientation in the
microstructure. The grain size was refined along with the increase in
the manganese content of the coating, which accordingly, raised its
hardness and resistance to annealing softening. In summary, the
Ni-Mn coating prepared at lower current density of 1-2 A/dm2 had low
internal stress, high leveling power, and better corrosion resistance.
Abstract: The phytotoxicity of heavy metals can be expressed
on roots and visible part of plants and is characterized by molecular
and metabolic answers at various levels of organization of the whole
plant. The present study was undertaken on two varieties of broad
bean Vicia faba (Sidi Aïch and Super Aguadulce). The device was
mounted on a substrate prepared by mixing sand, soil and compost,
the substrate was artificially contaminated with three doses of lead
nitrate [Pb(NO3)2] 0, 500 and 1000 ppm. Our objective is to follow
the behavior of plant opposite the stress by evaluating the
physiological parameters. The results reveal a reduction in the
parameters of the productivity (chlorophyll and proteins production)
with an increase in the osmoregulators (soluble sugars and
proline).These results show that the production of broad bean is
strongly modified by the disturbance of its internal physiology under
lead exposure.
Abstract: In the present study, the properties of Al-Al2O3
nanocomposite hollow sphere structures were investigated. For this
reason, the Al-based nanocomposite hollow spheres with different
amounts of nano-alumina reinforcement (0-10wt %) and different
ratio of thickness to diameter (t/D: 0.06-0.3) were prepared via a
powder metallurgy method. Then, the effect of mentioned parameters
was studied on physical and quasi static mechanical properties of
their related prepared structures (open/closed cell) such as density,
hardness, strength, and energy absorption. It was found that, as the
t/D ratio increases the relative density, compressive strength and
energy absorption increase. The highest values of strength and energy
absorption were obtained from the specimen with 5 wt. % of
nanoparticle reinforcement, t/D of 0.3 (t=1 mm, D=400μm) as 22.88
MPa and 13.24 MJ/m3, respectively. The moderate specific strength
of prepared composites in the present study showed the good
consistency with the properties of others low carbon steel composite
with similar structure.