Abstract: Experiments have been carried out at the Latvia
University of Agriculture Department of Food Technology. The aim
of this work was to assess the effect of thermal treatment in flexible
retort pouch packaging on the quality of potatoes’ produce during the
storage time. Samples were evaluated immediately after retort
thermal treatment; and following 1; 2; 3 and 4 storage months at the
ambient temperature of +18±2ºC in vacuum packaging from
polyamide/polyethylene (PA/PE) and aluminum/polyethylene
(Al/PE) film pouches with barrier properties. Experimentally the
quality of the potatoes’ produce in dry butter and mushroom
dressings was characterized by measuring pH, hardness, color,
microbiological properties and sensory evaluation. The sterilization
was effective in protecting the produce from physical, chemical, and
microbial quality degradation. According to the study of obtained
data, it can be argued that the selected product processing technology
and packaging materials could be applied to provide the safety and
security during four-month storage period.
Abstract: A study concerning the photocatalytic decolourization
of Congo red (CR) dye, over artificial UV irradiation is presented.
Photocatalysts based on a commercial titanium dioxide (TiO2)
modified with transition metals (Ni, Cu and Zn) were used. The
dopage method used was wet impregnation. A TiO2 sample without
salt was subjected to the same hydrothermal treatment to be used as
reference. Congo red solutions to several pH conditions (natural and
basic) were used to evaluate photocatalytic performance of each
doped catalysts. Photodecolourization percentage was measured
spectrofotrometically after 3 h of treatment to 499 nm as response
variable. Kinetics investigations of photodegradation indicated that
reactions obey to Langmuir-Hinshelwood model and pseudo–first
order law. The rate constant studies of photocatalytic decolourization
reactions for Zn–TiO2 and Cu–TiO2 photocatalysts indicated that in
all cases the rate constant of the reaction was higher than that of TiO2
undoped. These results show that nature of the metal modifying the
TiO2 influence on the efficiency of the photocatalyst evaluated in
process. Ni does not present an additional effect compared with TiO2,
while Zn enhances the photoactivity due to its electronic properties.
Abstract: In this research, several physical and chemical properties and mineral contents of Russion olive (Elaeagnus angustifolia L.) fruit grown in Turkey were determined. In the fruit, length, width, thickness, weight were determined as 2.866cm, 1.880cm, 1.870cm, 2.90g; total soluble solids and colour were determined as 13.14% and S33O60Y99, respectively. In the seed, mean length, width, thickness, and weight were found to be 2.420cm, 0.508cm, 0.503cm, and 0.38g, respectively. In the fruit, 28 minerals (K, P, Ca, Na, Mg, S, Pb, Ba, Ga, As, In, Ti, Fe, Mn, Zn, Cu, Co, B, Cd, Se, Li, Sr, Al, Ni, Ag, V, Cr, Bi) were analyzed and 19 minerals were present at detectable levels. Russion olive fruit was richest in potassium (10296.906ppm), Mg (762.314ppm), P (609.694ppm), Ca (547.647ppm), and Na (222.749ppm).
Abstract: The influence of extrusion parameters on surface
quality and properties of AA6061+x% vol. SiC (x = 0; 2,5; 5; 7,5;10)
composites was discussed in this paper. The averages size of
AA6061 and SiC particles were 10.6 μm and 0.42 μm, respectively.
Two series of composites (I - compacts were preheated at extrusion
temperature through 0.5 h and cooled by water directly after process;
II - compacts were preheated through 3 hours and were not cooled)
were consolidated via powder metallurgy processing and extruded by
KoBo method. High values of density for both series of composites
were achieved. Better surface quality was observed for II series of
composites. Moreover, for these composites lower (compared to I
series) but more uniform strength properties over the cross-section of
the bar were noticed. Microstructure and Young-s modulus
investigations were made.
Abstract: Characteristics of ad hoc networks and even their existence depend on the nodes forming them. Thus, services and applications designed for ad hoc networks should adapt to this dynamic and distributed environment. In particular, multicast algorithms having reliability and scalability requirements should abstain from centralized approaches. We aspire to define a reliable and scalable multicast protocol for ad hoc networks. Our target is to utilize epidemic techniques for this purpose. In this paper, we present a brief survey of epidemic algorithms for reliable multicasting in ad hoc networks, and describe formulations and analytical results for simple epidemics. Then, P2P anti-entropy algorithm for content distribution and our prototype simulation model are described together with our initial results demonstrating the behavior of the algorithm.
Abstract: The catalytic dehydroxylation of glycerol to propylene
glycol was investigated over Cu-ZnO/Al2O3 prepared by incipient
wetness impregnation (IWI) method with different purity feedstocks -
refined glycerol and technical grade glycerol. The main purpose is to
investigate the effects of feed impurities that cause the catalyst
deactivation. The prepared catalyst were tested for its catalytic
activity and selectivity in a continuous flow fixed bed reactor at 523
K, 500 psig, H2/feed molar ratio of 4 and WHSV of 3 h-1. The results
showed that conversion of refined glycerol and technical grade
glycerol at time on stream 6 hour are 99% and 71% and selectivity to
propylene glycol are 87% and 56% respectively. The ICP-EOS and
TPO results indicated that the cause of catalyst deactivation was the
amount of impurities in the feedstock. The higher amount of
impurities (especially Na and K) the lower catalytic activity.
Abstract: Hysitron TriboIndenterTM TI 950 system has been
used for studying the local viscoelastic properties of porcine
intervertebral disc end plate by means of nanoscale mechanical
dynamic analysis. The specimen of an endplate was cut from fresh
porcine vertebra dissected from 16 month animal. The lumbar spine
motion segments were dissected and 5 millimeter thick plates of
vertebral body, endplate and annulus fibrosus were prepared for
nanoindentation. The surface of the sample was kept in physiological
solution during nanoindentation experiment. We obtained mechanical
characteristics of different areas of native endplate (endplate middle
and vertebra and annulus fibrosus boundary).
Abstract: The accelerated sonophotocatalytic degradation of
Reactive Red (RR) 120 dye under visible light using dye sensitized
TiO2 activated by ultrasound has been carried out. The effect of
sonolysis, photocatalysis and sonophotocatalysis under visible light
has been examined to study the influence on the degradation rates by
varying the initial substrate concentration, pH and catalyst loading to
ascertain the synergistic effect on the degradation techniques.
Ultrasonic activation contributes degradation through cavitation
leading to the splitting of H2O2 produced by both photocatalysis and
sonolysis. This results in the formation of oxidative species, such as
singlet oxygen (1O2) and superoxide (O2
-●) radicals in the presence of
oxygen. The increase in the amount of reactive radical species which
induce faster oxidation of the substrate and degradation of
intermediates and also the deaggregation of the photocatalyst are
responsible for the synergy observed under sonication. A
comparative study of photocatalysis and sonophotocatalysis using
TiO2, Hombikat UV 100 and ZnO was also carried out.
Abstract: The zinc and iron environments in different growth
stages have been studied with EXAFS and XANES with Brookhaven
Synchrotron Light Source. Tissue samples included meat, organ,
vegetable, leaf, and yeast. The project studied the EXAFS and
XANES of tissue samples using Zn and Fe K-edges. Duck embryo
samples show that brain and intestine would contain shorter EXFAS
determined Zn-N/O bond; as with the cases of fresh yeast versus
reconstituted live yeast and green leaf versus yellow leaf. The
XANES Fourier transform characteristic-length would be useful as a
functionality index for selected types of tissue samples in various
physical states. The extension to the development of functional
synchrotron imaging for tissue engineering application based on
spectroscopic technique is discussed.
Abstract: Some physico-chemical characteristics and mineral
composition of 'Karayemis' (Prunus laurocerasus L.) fruits which
grown naturally in Norteast Turkey was studied. 28 minerals ( Al,
Mg, B, Mn, Co, Na, Ca, Ni, Cd, P, Cr, Pb, Cu, S, Fe, Zn, K, Sr, Li,
As, V, Ag, Ba, Br, Ga, In, Se, Ti) were analyzed and 19 minerals
were present at ascertainable levels. Karayemis fruit was richest in
potassium (7938.711 ppm), magnesium (1242.186 ppm) and calcium
(1158.853 ppm). And some physico-chemical characteristics of
Karayemis fruit was investigated. Fruit length, fruit width, fruit
thickness, fruit weight, total soluble solids, colour, protein, crude ash,
crude fiber, crude oil values were determined as 2.334 cm, 1.884 cm,
2.112 cm, 5.35 g, 20.1 %, S99M99Y99, 0.29 %, 0.22 %, 6.63 % and
0.001 %, respectively. The seed of fruit mean weight, length, width
and thickness were found to be 0.41 g, 1.303 cm, 0.921 cm and
0.803, respectively.
Abstract: The mineral having chemical compositional formula MgAl2O4 is called “spinel". The ferrites crystallize in spinel structure are known as spinel-ferrites or ferro-spinels. The spinel structure has a fcc cage of oxygen ions and the metallic cations are distributed among tetrahedral (A) and octahedral (B) interstitial voids (sites). The X-ray diffraction (XRD) intensity of each Bragg plane is sensitive to the distribution of cations in the interstitial voids of the spinel lattice. This leads to the method of determination of distribution of cations in the spinel oxides through XRD intensity analysis. The computer program for XRD intensity analysis has been developed in C language and also tested for the real experimental situation by synthesizing the spinel ferrite materials Mg0.6Zn0.4AlxFe2- xO4 and characterized them by X-ray diffractometry. The compositions of Mg0.6Zn0.4AlxFe2-xO4(x = 0.0 to 0.6) ferrites have been prepared by ceramic method and powder X-ray diffraction patterns were recorded. Thus, the authenticity of the program is checked by comparing the theoretically calculated data using computer simulation with the experimental ones. Further, the deduced cation distributions were used to fit the magnetization data using Localized canting of spins approach to explain the “recovery" of collinear spin structure due to Al3+ - substitution in Mg-Zn ferrites which is the case if A-site magnetic dilution and non-collinear spin structure. Since the distribution of cations in the spinel ferrites plays a very important role with regard to their electrical and magnetic properties, it is essential to determine the cation distribution in spinel lattice.
Abstract: Turkey has 72 % of total world boron reserves on the
basis of B2O3.Borates that is a refined form of boron minerals have a
wide range of applications. Zinc borates can be used as multifunctional
synergistic additives. The most important properties are
low solubility in water and high dehydration temperature. Zinc
borates dehydrate above 290°C and anhydrous zinc borate has
thermal resistance about 400°C. Zinc borates can be synthesized
using several methods such as hydrothermal and solid-state
processes. In this study, the solid-state method was applied between
500 and 800°C using the starting materials of ZnO and H3BO3 with
1:4 mole ratio. The reaction time was determined as 4 hours after
some preliminary experiments. After the synthesis, the crystal
structure and the morphology of the products were examined by XRay
Diffraction (XRD), Fourier Transform Infrared Spectroscopy
(FT-IR) and Raman Spectrometer. As a result the form of ZnB4O7
was synthesized with the highest crystal score at 800°C.
Abstract: Magnesium is used implant material potentially for
non-toxicity to the human body. Due to the excellent
bio-compatibility, Mg alloys is applied to implants avoiding removal
second surgery. However, it is found commercial magnesium alloys
including aluminum has low corrosion resistance, resulting
subcutaneous gas bubbles and consequently the approach as
permanent bio-materials. Generally, Aluminum is known to pollution
substance, and it raises toxicity to nervous system. Therefore
especially Mg-35Zn-3Ca alloy is prepared for new biodegradable
materials in this study. And the pulsed power is used in
constant-current mode of DC power kinds of anodization. Based on
the aforementioned study, it examines corrosion resistance and
biocompatibility by effect of current and frequency variation. The
surface properties and thickness were compared using scanning
electronic microscopy. Corrosion resistance was assessed via
potentiodynamic polarization and the effect of oxide layer on the body
was assessed cell viability. Anodized Mg-35Zn-3Ca alloy has good
biocompatibility in vitro by current and frequency variation.
Abstract: The camera parameters are changed due to temperature
variations, which directly influence calibrated cameras accuracy.
Robustness of calibration methods were measured and their accuracy
was tested. An error ratio due to camera parameters change
with respect to total error originated during calibration process was
determined. It pointed out that influence of temperature variations
decrease by increasing distance of observed objects from cameras.
Abstract: With the implied volatility as an important factor in
financial decision-making, in particular in option pricing valuation,
and also the given fact that the pricing biases of Leland option pricing
models and the implied volatility structure for the options are related,
this study considers examining the implied adjusted volatility smile
patterns and term structures in the S&P/ASX 200 index options using
the different Leland option pricing models. The examination of the
implied adjusted volatility smiles and term structures in the
Australian index options market covers the global financial crisis in
the mid-2007. The implied adjusted volatility was found to escalate
approximately triple the rate prior the crisis.
Abstract: Nanophotocatalysts such as titanium (TiO2), zinc (ZnO), and iron (Fe2O3) oxides can be used in organic pollutants oxidation, and in many other applications. But among the challenges for technological application (scale-up) of the nanotechnology scientific developments two aspects are still little explored: research on environmental risk of the nanomaterials preparation methods, and the study of nanomaterials properties and/or performance variability. The environmental analysis was performed for six different methods of ZnO nanoparticles synthesis, and showed that it is possible to identify the more environmentally compatible process even at laboratory scale research. The obtained ZnO nanoparticles were tested as photocatalysts, and increased the degradation rate of the Rhodamine B dye up to 30 times.
Abstract: The research object was wheat bread. Experiments
were carried out at the Faculty of Food Technology of the Latvia
University of Agriculture. An active packaging in combination with
modified atmosphere (MAP, CO2 60% and N2 40%) was examined
and compared with traditional packaging in air ambiance. Polymer
Multibarrier 60, PP and OPP bags were used. Influence of iron based
oxygen absorber in sachets of 100 cc obtained from Mitsubishi Gas
Chemical Europe Ageless® was tested on the quality during the shelf
of wheat bread. Samples of 40±4 g were packaged in polymer
pouches (110 mm x 120 mm), hermetically sealed by MULTIVAC
C300 vacuum chamber machine, and stored in room temperature
+21.0±0.5 °C. The physiochemical properties – weight losses,
moisture content, hardness, pH, colour, changes of atmosphere
content (CO2 and O2) in headspace of packs, and microbial
conditions were analysed before packaging and in the 7th, 14th, 21st
and 28th days of storage.
Abstract: The selective recovery of heavy metals of Cu, Zn, Ni and Cr from a mixed plating sludge by sulfidation and oxidation treatment was targeted in this study. At first, the mixed plating sludge was simultaneously subjected to an extraction and Cu sulfidation process at pH=1.5 to dissolve heavy metals and to precipitate Cu2+ as CuS. In the next step, the sulfidation treatment of Zn was carried out at pH=4.5 and the residual solution was subjected to an oxidation treatment of chromium with H2O2 at pH=10.0. After the experiments, the selectivity of metal precipitation and the chromium oxidation ratio were evaluated. As results, it was found that the filter cake obtained after selective sulfidation of Cu was composed of 96.6% of Cu (100% equals to the sum of Cu, Zn, Ni and Cr contents). Such findings confirmed that almost complete extraction of heavy metals was achieved at pH=1.5 and also that Cu could be selectively recovered as CuS. Further, the filter cake obtained at pH=4.5 was composed of 91.5% Zn and 6.83% of Cr. Regarding the chromium oxidation step, the chromium oxidation ratio was found to increase with temperature and the addition of oxidation agent of H2O2, but only oxidation ratio of 59% was achieved at a temperature of 60°C and H2O2 to Cr3+ equivalent ratio of 180.
Abstract: ZnO-SnO2 i.e. Zinc-Tin-Oxide (ZTO) thin films were
deposited on glass substrate with varying concentrations (ZnO:SnO2
- 100:0, 90:10, 70:30 and 50:50 wt.%) at room temperature by flash
evaporation technique. These deposited ZTO film were annealed at
450 0C in vacuum. These films were characterized to study the effect
of annealing on the structural, electrical, and optical properties.
Atomic force microscopy (AFM) and Scanning electron microscopy
(SEM) images manifest the surface morphology of these ZTO thin
films. The apparent growth of surface features revealed the formation
of nanostructure ZTO thin films. The small value of surface
roughness (root mean square RRMS) ensures the usefulness in
optical coatings. The sheet resistance was also found to be decreased
for both types of films with increasing concentration of SnO2. The
optical transmittance found to be decreased however blue shift has
been observed after annealing.
Abstract: On-line (near infrared) spectroscopy is widely used to support the operation of complex process systems. Information extracted from spectral database can be used to estimate unmeasured product properties and monitor the operation of the process. These techniques are based on looking for similar spectra by nearest neighborhood algorithms and distance based searching methods. Search for nearest neighbors in the spectral space is an NP-hard problem, the computational complexity increases by the number of points in the discrete spectrum and the number of samples in the database. To reduce the calculation time some kind of indexing could be used. The main idea presented in this paper is to combine indexing and visualization techniques to reduce the computational requirement of estimation algorithms by providing a two dimensional indexing that can also be used to visualize the structure of the spectral database. This 2D visualization of spectral database does not only support application of distance and similarity based techniques but enables the utilization of advanced clustering and prediction algorithms based on the Delaunay tessellation of the mapped spectral space. This means the prediction has not to use the high dimension space but can be based on the mapped space too. The results illustrate that the proposed method is able to segment (cluster) spectral databases and detect outliers that are not suitable for instance based learning algorithms.