All posts by simiecoind

Corn cob

Density

Fly ash

Mechanical properties

 

The research presented in this paper aim to analyze the effects of cement replacement by fly ash in 10 vol. %, 20 vol. %, and 30 vol. % and, afterwards, the effects of mineral aggregates substitution by 50 vol. % with vegetal aggregates. The used vegetal aggregates were shredded corn cobs, and were investigated the density, the compressive and split tensile strength of concrete. The results revealed that fly ash, as cement partial replacement, decreased the compressive strength comparing to the reference concrete, meanwhile, the splitting tensile strength was improved when were used 10% and 20% vol. of fly ash. Fly ash had a positive effect on the compressive strength of the vegetal concrete, in the case of the composition with 10% and 30% vol. of industrial waste, and also on splitting tensile strength in the case of 10% and 20% vol. of replacement rate. The concrete density diminished with 1.67%, 3.12% and 3.82% in the case of 10%, 20% and 30% vol. cement replacement by fly ash, respectively. Corn cob aggregates led to a concrete density decreasing with almost 25% compared to reference concrete.

Activated carbon

Adsorption 

Aqueous solution

Chemical activation

Dynamic conditions

Nut shells

 

In the paper the eliminating strontium ions from groundwater by using the CAN-7
activated carbon under dynamic conditions has been studied. The activated carbon
CAN-7 is obtained by the chemical method, through the treatment with orthophosphoric acid at distinct temperatures. It has been proved that by the reduction of
the filtration rate of the solution containing strontium ions through the adsorbent
column, the strontium ion adsorption is increased. The adsorption of strontium ions
from aqueous solutions on the CAN-7 activated carbon has been measured at
different lengths of working layer of the adsorbent column and at different filtration
rates of the solution. The length of working layer of the column with CAN-7 has
been determined as a function of the initial concentration of strontium ions and
filtration rates. The activated carbon CAN-7 with adsorbed strontium ions is
completely regenerated by 0.36% of hydrochloric acid. The obtained results for the
process of adsorption of strontium ions from aqueous solutions on the CAN-7
activated carbon under dynamic conditions has demonstrated the option of removing
this pollutant from the deep waters.

Black locust

Cooper ore

Oleaster

Tailing dumps

Wood

 

The present paper emphasizes the possibility of using wood from the plantations installed on waste heaps by analysing the density of wood mass and establishing the biomass of species planted on the waste heaps from Moldova Noua. In order to determine wood biomass for the analysed species, wood samples were gathered from a specific sample area. As such, their volume and mass were established both
before and after drying them in a stove at a temperature of 105 degrees Celsius for 24 hours. The plantations biomass was calculated by using wood density according to the work method previously described as well as the wood mass volume per hectare. The last element was determined after biometric measurements realized in
12 sample surfaces of 100 square meters each, arranged in four variants with three recursions. In the specific case of Moldova Noua waste heaps, the values obtained for wood density attest the high-quality wood of these plantations from the point of view of their density, in comparison with the wood from similar species grown
under favourable vegetation conditions. Furthermore, analysing the productivity of plantations installed on the waste heaps from Moldova Noua, attest the framing of these plantations in an inferior production class from a productive point of view. The papers conclusions discuss the obtained results in the context of data from specialty literature concerning the productivity and wood density of forest plantations from the waste heaps located in Moldova Noua.

Anolyte water

Squalene

Fodder protein

Growths activation

S. fibuligera Y-436

 

The phenomenon of growth activation of the industrial strain of mycelial fungus S.
fibuligera Y-436 under the influence of squalene and anolyte water has been
investigated. Squalene had a stimulating effect on the growth of the strain on YEPD
Broth in all doses. The stimulating effect of squalene was maintained for 54 hours,
in a dose of 0.0005% – up to 78 hours of the strain cultivation under aerobic
conditions. The growth rate of the strain in the exponential phase between 4 and 6
hours on medium with a squalene of 0.0005 % is 0.30, 0.001 % – 0.44, 0.002 % –
0.41, on medium without squalene – 0.24. Squalene promotes faster adaptation of
the strain to the substrate and reduces the duration of its lag phase of growth by 2-4 hours. The number of cells increases by 2.2-2.3 times with the use of squalene in
doses of 0.0005-0.001 % after 24 hours and by 1.4 times after 48 hours of
incubation on the nutritional mixture based on wheat flour. The strain reached the
stationary phase after 24 hours of cultivation with the use of squalene, while in the
control variant – after 48 hours. This reduces the duration of cultivation by 2 times.
Anolyte water contributed to the rise of generative activity of the strain due to the
acid reaction by 34.3 % in comparison with the initial water. The most effective
method of activation of the strain is the combined use of anolyte water and squalene in a dose of 0.0005-0.001 %.

Alga

Carbohydrate

Hydrothermal hydrolysis

Ionic liquid

Ulva sp.

 

Macroalgae represent a worldwide spread renewable source of valuable
biopolymers, polysaccharides and proteins that after pretreatment constitute an
intermediate platform for microbial and chemical production. In the present study
the potential of some ionic liquids (ILs) to extract and hydrolyze the algal
carbohydrates derived from Ulva sp. is examined and compared to the conventional
inorganic acid catalysts, H2SO4 and HCl. The experimental results reveal that the IL,
1 -butyl-3-methylimidazolium acetate, is superior to both acid auxiliaries in
extracting carbohydrates. The capacity of this IL for splitting reducing sugars under
the conditions of hydrothermal hydrolysis is comparable with the power of HCl, but
higher than HCl in terms of monosugar fraction and protein released. The highest
yields of reducing and monosugars and of protein are obtained by using the strong
dibasic acid, H2SO4. It could, however, produce dehydration by–products which
would incur inhibition of enzymatic and microbial processes fed by the algal liquor.