Abstract: Metal thin-walled members have been widely used in
building industry. Usually they are utilized as purlins, girts or ceiling
beams. Due to slenderness of thin-walled cross-sections these
structural members are prone to stability problems (e.g. flexural
buckling, lateral torsional buckling). If buckling is not
constructionally prevented their resistance is limited by buckling
strength. In practice planar members of roof or wall cladding can be
attached to thin-walled members. These elements reduce
displacement of thin-walled members and therefore increase their
buckling strength. If this effect is taken into static assessment more
economical sections of thin-walled members might be utilized and
certain savings of material might be achieved. This paper focuses on
problem of determination of critical load of steel thin-walled beams
with lateral continuous restraint which is crucial for lateral torsional
buckling assessment.
Abstract: This study is aiming at establishing the relationship
between the optical signal of flame and an equivalent ratio of flame. In
this experiment, flame optical signal in a furnace is measured using
photodiode. The combustion system is composed of metal fiber burner
and vertical furnace, and flame chemiluminescence is measured at
various experimental conditions. In this study, the flame
chemiluminescence of laminar premixed flame is measured using
commercially available photodiode. It is experimentally investigated
the relationship between equivalent ratio and photodiode signal. In
addition, the strategy of combustion control method is proposed using
the optical signal and fuel pressure.
The results showed that certain relationship between optical data of
photodiode and equivalence ratio exists, and this leads to the
successful application of this system for instantaneous measurement of
equivalence ration of the combustion system.
Abstract: Current research is targeting new molecular
mechanisms that underlie non-alcoholic fatty liver disease (NAFLD)
and associated metabolic disorders like non-alcoholic steatohepatitis
(NASH). Forty New Zealand White rabbits have been used and fed a
high protein (HP) and energy diet based on grains and containing
11.76 MJ/kg. Boron added to 3 experimental groups’ drinking waters
(30 mg boron/L) as boron compounds. Biochemical analysis
including boron levels, and nuclear magnetic resonance (NMR) based
metabolomics evaluation, and mRNA expression of peroxisome
proliferator-activated receptor (PPAR) family was performed. LDLcholesterol
concentrations alone were decreased in all the
experimental groups. Boron levels in serum and feces were increased.
Content of acetate was in about 2x higher for anhydrous borax group,
at least 3x higher for boric acid group. PPARα mRNA expression
was significantly decreased in boric acid group. Anhydrous borax
attenuated mRNA levels of PPARγ, which was further suppressed by
boric acid. Boron supplementation decreased the degenerative
alterations in hepatocytes. Except borax group other boron groups did
not have a pronounced change in tubular epithels of kidney. In
conclusion, high protein and energy diet leads hepatocytes’
degenerative changes which can be prevented by boron
supplementation. Boric acid seems to be more effective in this
situation.
Abstract: Development of new generation bio-tribological,
multilayer coatings opens an avenue for fabrication of future hightech
functional surfaces. In the presented work, nano-composite,
Cr/CrN+[Cr/ a-C:H implanted by metallic nanocrystals] multilayer
coatings have been developed for surface protection of medical tools.
Thin films were fabricated by a hybrid Pulsed Laser Deposition
technique. Complex microstructure analysis of nanomultilayer
coatings, subjected to mechanical and biological tests, were
performed by means of transmission electron microscopy (TEM).
Microstructure characterization revealed the layered arrangement of
Cr23C6 nanoparticles in multilayer structure. Influence of deposition
conditions on bio-tribological properties of the coatings was studied.
The bio-tests were used as a screening tool for the analyzed
nanomultilayer coatings before they could be deposited on medical
tools. Bio-medical tests were done using fibroblasts. The mechanical
properties of the coatings were investigated by means of a ball-ondisc
mechanical test. The micro hardness was done using Berkovich
indenter. The scratch adhesion test was done using Rockwell
indenter. From the bio-tribological point of view, the optimal
properties had the C106_1 material.
Abstract: WO3/SiO2 catalysts were modified by an ion exchange
method with sodium hydroxide or potassium hydroxide solution. The
performance of the modified catalysts was tested in the metathesis of
ethylene and trans-2-butene to propylene. During ion exchange,
sodium and potassium ions played different roles. Sodium modified
catalysts revealed constant trans-2-butene conversion and propylene
selectivity when the concentrations of sodium in the solution were
varied. In contrast, potassium modified catalysts showed reduction of
the conversion and increase of the selectivity. From these results,
potassium hydroxide may affect the transformation of tungsten oxide
active species, resulting in the decrease in conversion whereas
sodium hydroxide did not. Moreover, the modification of catalysts by
this method improved the catalyst stability by lowering the amount of
coke deposited on the catalyst surface.
Abstract: This study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.
Abstract: Microbes have been used to solve environmental
problems for many years. The role of microorganism to sequester,
precipitate or alter the oxidation state of various heavy metals has
been extensively studied. Treatment using microorganism interacts
with toxic metal are very diverse. The purpose of this research is to
remove the mercury using Pseudomonas putida (P. putida), pure
culture ATTC 49128 at optimum growth parameters such as
techniques of culture, acclimatization time and speed of incubator
shaker. Thus, in this study, the optimum growth parameters of P.
putida were obtained to achieve the maximum of mercury removal.
Based on the optimum parameters of P. putida for specific growth
rate, the removal of two different mercury concentration, 1 ppm and
4 ppm were studied. From mercury nitrate solution, a mercuryresistant
bacterial strain which is able to reduce from ionic mercury
to metallic mercury was used to reduce ionic mercury. The overall
levels of mercury removal in this study were between 80% and 89%.
The information obtained in this study is of fundamental for
understanding of the survival of P. putida ATTC 49128 in mercury
solution. Thus, microbial mercury removal is a potential
bioremediation for wastewater especially in petrochemical industries
in Malaysia.
Abstract: Potassium borates, which are widely used in welding
and metal refining industry, as a lubricating oil additive, cement
additive, fiberglass additive and insulation compound, are one of the
important groups of borate minerals. In this study the production of a
potassium borate mineral via hydrothermal method is aimed. The
potassium source of potassium nitrate (KNO3) was used along with a
sodium source of sodium hydroxide (NaOH) and boron source of
boric acid (H3BO3). The constant parameters of reaction temperature
and reaction time were determined as 80°C and 1 h, respectively. The
molar ratios of 1:1:3 (as KNO3:NaOH:H3BO3), 1:1:4, 1:1:5, 1:1:6
and 1:1:7 were used. Following the synthesis the identifications of
the produced products were conducted by X-Ray Diffraction (XRD),
Fourier Transform Infrared Spectroscopy (FT-IR) and Raman
Spectroscopy. The results of the experiments and analysis showed in
the ratio of 1:1:6, the Santite mineral with powder diffraction file
number (pdf no.) of 01-072-1688, which is known as potassium
pentaborate (KB5O8·4H2O) was synthesized as best.
Abstract: Electrodeposition is a simple and economic technique
for precision coating of different shaped substrates with pure metal,
alloy or composite films. Dc electrodeposition was used to produce
Cr, Co-Cr and Co-Cr/TiO2 nano-composite coatings from Cr(III)
based electrolytes onto 316L SS substrates. The effects of TiO2 nanoparticles
concentration on co-deposition of these particles along with
Cr content and microhardness of the coatings were investigated.
Morphology of the Cr, Co-Cr and Co-Cr/TiO2 coatings besides their
tribological behavior were studied. The results showed that increment
of TiO2 nanoparticles concentration from 0 to 30 g L-1 in the bath
increased their co-deposition and Cr content of the coatings from 0 to
3.5 wt.% and from 23.7 to 31.2 wt.%, respectively. Microhardness of
Cr coating was about 920 Hv which was higher than Co-Cr and even
Co-Cr/TiO2 films. Microhardness of Co-Cr and Co-Cr/TiO2 coatings
were improved by increasing their Cr and TiO2 content. All the
coatings had nodular morphology and contained microcracks.
Nodules sizes and the number of microcracks in the alloy and
composite coatings were lower than the Cr film. Wear results
revealed that the Co-Cr/TiO2 coating had the lowest wear loss
between all the samples, while the Cr film had the worst wear
resistance.
Abstract: The addition of lime as Ca(OH)2 to sewage sludge to
destroy pathogens (Escherichia coli), was evaluated also in relation
to heavy metal bioavailability.
The obtained results show that the use of calcium hydroxide at the
dose of 3% effectively destroyed pathogens ensuring the stability at
high pH values over long period and the duration of the sewage
sludge stabilization. In general, lime addition decreased the total
extractability of heavy metals indicating a reduced bioavailability of
these elements. This is particularly important for a safe utilization in
agricultural soils to reduce the possible transfer of heavy metals to
the food chain.
Abstract: Froth flotation remains to date as one of the most used
metallurgical processes for concentrating metal-bearing minerals in
ores. Oxide ores are relatively less amenable to froth flotation and
require a judicious choice of reagents for the recovery of metals to be
optimised. Laboratory batch flotation tests were conducted to
determine the effect of two types of gasoil-rinkalore mixtures on the
flotation response of a copper cobalt oxide ore sample. The head
assay conducted on the initial ore sample showed that it contained
about 2.90% of Cu, 0.12% of Co.
Upon the flotation test work, the results obtained indicated that the
concentrate obtained with use of the mixture gazoil-rinkalore RX
yielded 8.24% Cu and 0.22% Co concentrate grades with recoveries
of 76.0% Cu and 78.0% Co respectively. But, the concentrate
obtained by use of the mixture gazoil-rinkalore RX3 yielded
relatively bad results with 5.92% Cu and 0.18% Cu concentrate
grades with recoveries of 70.3% Cu and 65.3% Co respectively.
Abstract: Intermetallic materials are among advanced
technology materials that have outstanding mechanical and physical
properties for high temperature applications. Especially creep
resistance, low density and high hardness properties stand out in such
intermetallics. The microstructure, mechanical properties of %88Ni-
%10Cr and %2Mn powders were investigated using specimens
produced by tube furnace sintering at 900-1300°C temperature. A
composite consisting of ternary additions, a metallic phase, Fe, Cr
and Mn have been prepared under Ar shroud and then tube furnace
sintered. XRD, SEM (Scanning Electron Microscope), were
investigated to characterize the properties of the specimens.
Experimental results carried out for composition %88Ni-%10Cr and
%2Mn at 1300°C suggest that the best properties as 138,80HV and
6,269/cm3 density were obtained at 1300°C.
Abstract: Microstructural and electrical properties of
Cu-chromium alloy (Cu-Cr) dispersed with vapor-grown carbon fiber
(VGCF) prepared by powder metallurgy (P/M) process have been
investigated. Cu-0.7 mass% Cr pre-alloyed powder (Cu-Cr) made by
water atomization process was used as raw materials, which contained
solid solute Cr elements in Cu matrix. The alloy powder coated with
un-bundled VGCF by using oil coating process was consolidated at
1223 K in vacuum by spark plasma sintering, and then extruded at
1073 K. The extruded Cu-Cr alloy (monolithic alloy) had 209.3 MPa
YS and 80.4 IACS% conductivity. The extruded Cu-Cr with 0.1
mass% VGCF composites revealed a small decrease of YS compared
to the monolithic Cu-Cr alloy. On the other hand, the composite had a
higher electrical conductivity than that of the monolithic alloy. For
example, Cu-Cr with 0.1 mass% VGCF composite sintered for 5 h
showed 182.7 MPa YS and 89.7 IACS% conductivity. In the case of
Cu-Cr with VGCFs composites, the Cr concentration was observed
around VGCF by SEM-EDS analysis, where Cr23C6 compounds were
detected by TEM observation. The amount of Cr solid solution in the
matrix of the Cu-Cr composites alloy was about 50% compared to the
monolithic Cu-Cr sintered alloy, and resulted in the remarkable
increment of the electrical conductivity.
Abstract: The aim of this study is to investigate formability of
Al based closed cell metallic foams at high temperature. The foam
specimens with rectangular section were produced from
AlMg1Si0.6TiH20.8 alloy preform material. Bending and free
bending tests based on gravity effect were applied to foam specimens
at high temperatures. During the tests, the time-angular deformation
relationships with various temperatures were determined.
Deformation types formed in cell walls were investigated by means
of Scanning Electron Microscopy (SEM) and optical microscopy.
Bending deformation about 90° was achieved without any defect at
high temperatures. The importance of a critical temperature and
deformation rate was emphasized in maintaining the deformation.
Significant slip lines on surface of cell walls at tensile zones of
bending specimen were observed. At high strain rates, the microcrack
formation in boundaries of elongated grains was determined.
Abstract: This paper introduces symbiotic organism search (SOS)
for solving capacitated vehicle routing problem (CVRP). SOS is a new
approach in metaheuristics fields and never been used to solve discrete
problems. A sophisticated decoding method to deal with a discrete
problem setting in CVRP is applied using the basic symbiotic
organism search (SOS) framework. The performance of the algorithm
was evaluated on a set of benchmark instances and compared results
with best known solution. The computational results show that the
proposed algorithm can produce good solution as a preliminary
testing. These results indicated that the proposed SOS can be applied
as an alternative to solve the capacitated vehicle routing problem.
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: This research paper presents highly optimized barrel
shifter at 22nm Hi K metal gate strained Si technology node. This
barrel shifter is having a unique combination of static and dynamic
body bias which gives lowest power delay product. This power delay
product is compared with the same circuit at same technology node
with static forward biasing at ‘supply/2’ and also with normal reverse
substrate biasing and still found to be the lowest. The power delay
product of this barrel sifter is .39362X10-17J and is lowered by
approximately 78% to reference proposed barrel shifter at 32nm bulk
CMOS technology. Power delay product of barrel shifter at 22nm Hi
K Metal gate technology with normal reverse substrate bias is
2.97186933X10-17J and can be compared with this design’s PDP of
.39362X10-17J. This design uses both static and dynamic substrate
biasing and also has approximately 96% lower power delay product
compared to only forward body biased at half of supply voltage. The
NMOS model used are predictive technology models of Arizona state
university and the simulations to be carried out using HSPICE
simulator.
Abstract: Purpose: The study aimed to assess the depressant or
antidepressant effects of several Nonsteroidal Anti-Inflammatory
Drugs (NSAIDs) in mice: the selective cyclooxygenase-2 (COX-2)
inhibitor meloxicam, and the non-selective COX-1 and COX-2
inhibitors lornoxicam, sodium metamizole, and ketorolac. The
current literature data regarding such effects of these agents are
scarce.
Materials and methods: The study was carried out on NMRI mice
weighing 20-35 g, kept in a standard laboratory environment. The
study was approved by the Ethics Committee of the University of
Medicine and Pharmacy „Carol Davila”, Bucharest. The study agents
were injected intraperitoneally, 10 mL/kg body weight (bw) 1 hour
before the assessment of the locomotor activity by cage testing (n=10
mice/ group) and 2 hours before the forced swimming tests (n=15).
The study agents were dissolved in normal saline (meloxicam,
sodium metamizole), ethanol 11.8% v/v in normal saline (ketorolac),
or water (lornoxicam), respectively. Negative and positive control
agents were also given (amitryptilline in the forced swimming test).
The cage floor used in the locomotor activity assessment was divided
into 20 equal 10 cm squares. The forced swimming test involved
partial immersion of the mice in cylinders (15/9cm height/diameter)
filled with water (10 cm depth at 28C), where they were left for 6
minutes. The cage endpoint used in the locomotor activity assessment
was the number of treaded squares. Four endpoints were used in the
forced swimming test (immobility latency for the entire 6 minutes,
and immobility, swimming, and climbing scores for the final 4
minutes of the swimming session), recorded by an observer that was
„blinded” to the experimental design. The statistical analysis used the
Levene test for variance homogeneity, ANOVA and post-hoc
analysis as appropriate, Tukey or Tamhane tests.
Results: No statistically significant increase or decrease in the
number of treaded squares was seen in the locomotor activity
assessment of any mice group. In the forced swimming test,
amitryptilline showed an antidepressant effect in each experiment, at
the 10 mg/kg bw dosage. Sodium metamizole was depressant at 100
mg/kg bw (increased the immobility score, p=0.049, Tamhane test),
but not in lower dosages as well (25 and 50 mg/kg bw). Ketorolac
showed an antidepressant effect at the intermediate dosage of 5
mg/kg bw, but not so in the dosages of 2.5 and 10 mg/kg bw,
respectively (increased the swimming score, p=0.012, Tamhane test).
Meloxicam and lornoxicam did not alter the forced swimming
endpoints at any dosage level.
Discussion: 1) Certain NSAIDs caused changes in the forced
swimming patterns without interfering with locomotion. 2) Sodium
metamizole showed a depressant effect, whereas ketorolac proved
antidepressant. Conclusion: NSAID-induced mood changes are not
class effects of these agents and apparently are independent of the
type of inhibited cyclooxygenase (COX-1 or COX-2).
Disclosure: This paper was co-financed from the European Social
Fund, through the Sectorial Operational Programme Human Resources Development 2007-2013, project number POSDRU /159
/1.5 /S /138907 "Excellence in scientific interdisciplinary research,
doctoral and postdoctoral, in the economic, social and medical fields
-EXCELIS", coordinator The Bucharest University of Economic
Studies.
Abstract: The concentrations of heavy metals in sediments of
Qua Iboe River Estuary (QIRE) were monitored at four different
sampling locations in wet and dry seasons. A preliminary survey to
determine the four sampling stations along the river continuum
showed that the area spanned between
Abstract: Phthalates are ubiquitous environmental pollutants
well known because of their endocrine disrupting activity in human
organism. The aim of our study was, by biological monitoring,
investigate exposure to phthalates of Roma ethnicity group i.e.
children and adults from 5 families (n=29, average age 11.8 ± 7.6
years) living in western Slovakia. Additionally, we analysed some
associations between anthropometric measures, questionnaire data
i.e. socio-economic status, eating and drinking habits, practise of
personal care products and household conditions in comparison with
concentrations of phthalate metabolites. We used for analysis of urine
samples high performance liquid chromatography and tandem mass
spectrometry (HPLC-MS/MS) to determine concentrations of
phthalate metabolites monoethyl phthalate (MEP), mono-n-butyl
phthalate (MnBP), mono-iso-butyl phthalate (MiBP), mono(2-ethyl-
5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl)
phthalate (5oxo-MEHP) and mono(2-etylhexyl) phthalate (MEHP).
Our results indicate that ethnicity, lower socioeconomic status and
different housing conditions in Roma population can affect urinary
concentration of phthalate metabolites.