Bubble Shape Influence on Slug Flow Acceleration Mechanism
EUGENIA TEODORA IACOB-TUDOSE, “Gheorghe Asachi” Technical University of
Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection, Department of Chemical Engineering, Iaşi, Romania,
etudose@ch.tuiasi.ro MASAHIRO
KAWAJI, The City College of New York, Grove School of Engineering, USA
Abstract A 7.5 cm long solid Taylor bubble with normal (nondeformed)
and distorted nose forms was placed in a liquid flowing downward in a
vertical tube and the total drag force was measured. For both normal and
deformed bubbles, variations in drag force with solid bubble displacement
from the tube axis were evaluated and compared. Aside from the steady
decrease in drag force from the tube axis to the wall, the deformed nose
bubble experienced less drag than the conventional nose bubble, as expected.
Changes in the bubble nose shape result in a reduction in drag force. This
concept, when combined with the reduction in drag force caused by the
bubble's lateral displacement from the vertical pipe axis as described
previously (Tudose and Kawaji, 1999; Tudose, 2004), can explain the
acceleration of a trailing bubble following another. Keywords: two-phase
flow, pre-coalescence phenomena, Taylor bubble, nose, deformation
Optimization of Process Parameters for Retention of Cd(II) Ions
Adsorption from Aqueous Solutions on Clay Materials
BIANCA AZANFIRE, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania LAURA BULGARIU, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania,
lbulg@ch.tuiasi.ro
Abstract Globally, heavy metal pollution is classified as serious
environmental problem. Cd(II) ions are commonly encountered pollutants that
are toxic to human life, even at low concentration and adsorption is one of
the most suited process for this heavy metal ions removal from aqueous
solutions. Clay materials have risen as potential options in contrast to
conventional adsorbents. The adsorption properties of clay in retention of
Cd(II) from aqueous solutions have been studied in batch technique. The
amount of adsorbed heavy metal ions was determined for the adsorption
systems as a function of adsorbent dose, initial solution pH, initial ion
concentration, contact time and temperature. Based on the obtained
experimental results, the optimal values of the process parameters are:
initial solution pH 7.0, 4.0 g·L-1 adsorbent, 60 minutes of contact time
and ambient temperature. These conditions ensure a maximum removal
efficiency of Cd(II) ions of 93%. Keywords: water pollution, heavy
metals, cadmium ions, clay materials, adsorption
Aloe Vera Gel as a Biomordant in the Finishing of Vegetable Textiles: A
Review
ABDOURAMANE NSANGOU, Department of Mechanical Engineering, ENSET,
University of Douala, Cameroon DOINA SIBIESCU, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania,
dsibiesc@tuiasi.ro DYDIMUS EFEZE
NKEMAJA, HTTTC Bambili-University of Bamenda, Cameroon PIERRE MARCEL
ANICET NOAH, Department of Mechanical Engineering, ENSET, University of
Douala, Cameroon FABIEN EBANDA BETENE, Department of Mechanical
Engineering, ENSET, University of Douala, Cameroon VALERY HAMBATÉ
GOMDJÉ, Departments of Textile and Leather Engineering, ENSPM, University of
Maroua, Cameroon
Abstract During the dyeing process, the color is maintained over
time due to the mordant that creates a strong bond between the dye and the
fiber. The most common chemical mordants are potassium alum, tartar cream,
tin chloride, cupric sulfate, ferrous sulfate and potassium dichromate. The
current trend of increasing nature protection requires the use of clean
products for the textile finishing sector and the biodegradability of
textiles. Aloe vera is known to be a natural mordant. Based on data from the
literature, the authors of this paper aimed to identify several behaviors
between aloe vera gel and textiles. Aloe vera gel macerated on sida
rhombifolia shows (with the residue in the oven) after IR analysis a
disappearance of peak 1029 cm-1 which indicated the degree of C-O-C bonds of
cellulose present in the modification of sida rhombifolia. The active
ingredients of Aloe vera have also been shown to bind to the hydroxyl groups
of cotton, which is a crosslinking agent for macromolecules. Keywords:
Aloe vera gel, finishing, vegetable textile, biomordant
Application of Response Surface Method for Optimization of Eriochrome
Black T Removal by Adsorption
LOREDANA PINTILIE, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania,
pintilie.loredana88@yahoo.com ANDREEA-EMA SAVA, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania ELENA NICULINA
DRĂGOI, “Gheorghe Asachi” Technical University of Iaşi, “Cristofor
Simionescu” Faculty of Chemical Engineering and Environmental Protection,
Iaşi, Romania CARMEN TEODOSIU, “Gheorghe Asachi” Technical University of
Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection, Iaşi, Romania
Abstract This study used Response Surface Methodology (RSM) to
optimize Eriochrome Black T adsorption on activated carbon. Based on the
Design of Experiments approach, static and static-stirred experiments were
planned and conducted. Each set had 15 experiments and three replications at
the center point. Experiments were conducted at room temperature with no pH
adjustments. In static conditions, the maximum removal efficiency was
63.01%, while in static-stirred conditions, it was 78.18%. MINITAB 17.1.0
was used to analyze and interpret the experimental results. Linear,
factorial, quadratic, and cubic statistical models were developed to
describe static and static-stirred process parameter interactions. In
addition, 3-D response surface plots and 2-D contour plots were used to show
parameter efficiency. The RSM analysis of process parameters and their
influence on retention yield increased removal efficiencies up to 85.20% in
the static regime and to complete removal in the static-stirred regime,
demonstrating optimization's ability to improve process performances.
Keywords: adsorption, activated carbon, Eriochrome Black T, optimization,
Response Surface Methodology
Natural Extracts Used to Prevent Microbial Contamination of Cosmetic
Products
MIHAIL VÎNAGĂ, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania СORINA СERNATESСU, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania ALEXANDRA СRISTINA BLAGA,
“Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu”
Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania,
aсblaga@tuiasi.ro
Abstract The antimicrobial effect of some plants has been known
since ancient times and is the subject of scientific investigations even
today, being sometimes the reason for their use in cosmetics. Over the
years, a deeper understanding of the behavior of skin and plants has become
available, drawing increasingly complex images. Plants are complex organisms
that produce different metabolites as response to the environment in which
they live, and plant extracts and essential oils (when applied to the skin)
interact with skin cells and increase the well-being and appearance of the
skin. Ethnobotanical studies and physiсo-сhemiсal analyzes have presented a
rich inventory of plants with the potential to enrich and improve modern
cosmetics. Recently, a number of laboratory studies have revealed the
efficiency of plant extracts and phytochemicals as antimicrobials. The most
used plant materials that provide antimicrobial protection includes:
essential oils (rosemary, tea tree, turmeriс and rosehip seed oil), plant
extraсts (rosemary, rosehip, sage, lemon balm, green tea, Kaempferia
galanga, Neem leaf and Horseradish extract), isolated oil and phytoсhemiсals
such as cinnamate, benzoate, eugenol. Keywords: Natural extracts,
cosmetics, bioactive compounds, antimicrobial effect, plants
An Overview of Natural Organic Matter Removal by Coagulation in Drinking
Water Treatment
RAMONA CIOBANU, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Department of Environmental Engineering and Management, Iaşi,
Romania MARCELA MIHAI, “Petru Poni” Institute of Macromolecular
Chemistry, Iaşi, Romania CARMEN TEODOSIU, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Department of Environmental Engineering and
Management, Iaşi, Romania,
cteo@ch.tuiasi.ro
Abstract Natural organic matter (NOM) is equivalent to the total
organic substances resulting from bacterial decomposition of animal and
vegetal matter. NOM is naturally found in most surface water sources used
for drinking water supply, and can have significant impacts on human health
if it is not removed. Apart from the fact that they create problems with
taste, odour and color of raw water, NOM species are precursors of
disinfection by-products, which in turn have a negative effect on human
health. Most of the NOM can be removed by coagulation and flocculation
followed by sedimentation and filtration, processes that are considered the
most common and economically feasible drinking water treatments. This study
presents an overview of recently published investigations regarding NOM
removal in drinking water treatment with different coagulant types and
treatment techniques in relation to coagulation. Keywords: coagulation,
flocculation, natural organic matter
The Use of Calcium Carbonate as a Foaming Agent of Glass Waste for
Unconventional Manufacture of a Light Glass Foam with Adequate Mechanical
Strength
LUCIAN PĂUNESCU, Daily Sourcing & Research SRL Bucharest, Romania,
lucianpaunescu16@gmail.com SORIN MIRCEA AXINTE, Daily Sourcing & Research SRL Bucharest, Romania;
Department of Applied Chemistry and Materials Science, University
“Politehnica” of Bucharest, Romania FELICIA COSMULESCU, Cosfel Actual
SRL Bucharest, Romania BOGDAN VALENTIN PĂUNESCU, Consitrans SA
Bucharest, Romania
Abstract The paper presents experimental results of manufacturing a
glass foam of glass waste with excellent thermal insulation properties and
simultaneously relatively high compressive strength. The foaming agent was
calcium carbonate (CaCO3) and borax was used as a fluxing agent. The
achievement of the objective involved finding an appropriate correlation
between the foaming agent and the fluxing agent to obtain the desired
characteristics. The research originality was the use of the own technique
of predominantly direct microwave heating that ensures a high energy
efficiency of the thermal process. The optimal foam sample was made with
1.1% CaCO3 and 2% borax, by the heat treatment of glass waste at 825ºC. The
foamed product characteristics were: apparent density of 0.18 g/cm3,
porosity of 91%, thermal conductivity of 0.042 W/m·K and compressive
strength of 2.6 MPa. The high energy efficiency of the heating technique led
to a very low specific energy consumption (0.67 kWh/kg). Keywords: glass
foam, microwave heating, glass waste, calcium carbonate, borax