scholarly journals Effect of Time, Temperature and Stirring Rate Used in the First Step of the Synthesis of SBA-15 on Its Application as Reductor of Tars in Tobacco Smoke

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 375
Author(s):  
Nerea Juárez-Serrano ◽  
Javier Asensio ◽  
Inmaculada Blasco ◽  
Maribel Beltrán ◽  
Antonio Marcilla
Keyword(s):  
Tobacco Smoke ◽  
Short Fibers ◽  
N2 Adsorption ◽  
Synthesis Conditions ◽  
Stirring Rate ◽  
Reduction Effect ◽  
Tar Reduction ◽  
And Behavior ◽  
Long Fibers ◽  
Temperature Time

SBA-15 has been employed as a tobacco additive with the objective of reducing the toxic and carcinogenic components in tobacco smoke. The effect of the synthesis conditions (temperature, time, and stirring rate) on this application was studied in this paper. The SBA-15 was characterized (RDX, N2 adsorption isotherms, SEM and apparent density), mixed with the 3R4F reference tobacco, and smoked under standard conditions. The composition of the gas and condensed fractions also was analyzed. The morphology of the material plays an important role on this application and is highly influenced by the three variables studied. Long fibers show improved efficiency compared to short fibers. The tar reduction effect was improved when increasing the time of synthesis. Nevertheless, a maximum was observed with temperature (40 °C) and stirring rate (700 rpm). The optimal synthesis conditions obtained were 24 h, 40 °C and 700 rpm, yielding reductions as high as 68% for tar, 67% for nicotine, and 31% for CO. The scaling-up process has only been reported in terms of grams but never in a preindustrial scale (around 4 kg), and thus the results of this analysis show a promising material with properties and behavior similar with respect to the sample synthesized at laboratory scale.

scholarly journals Novel Biobased Textile Fiber from Colombian Agro-Industrial Waste Fiber

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2640 ◽  
Author(s):  
Maria Amaya Vergara ◽  
Melissa Cortés Gómez ◽  
Maria Restrepo Restrepo ◽  
Jorge Manrique Henao ◽  
Miguel Pereira Soto ◽  
...  
Keyword(s):  
Textile Industry ◽  
Industrial Waste ◽  
Degree Of Polymerization ◽  
Cellulose Content ◽  
Short Fibers ◽  
Cellulose Pulp ◽  
Potential Applications ◽  
Fique Fibers ◽  
Regenerated Fibers ◽  
Long Fibers

Fique fibers, native to Colombia, are traditionally used for ropes and bags. In the extraction of long fibers for these purposes, the same amount of short fibers is generated; the short fibers are then discarded in the soil or in landfills. This agro-industrial waste is cellulose-rich and can be potentially developed into new biobased products. As an alternative use for these fibers, viscose regenerated fibers with potential applications in the textile industry were developed. Fique waste fibers were pulped (to produce fique cellulose pulp, FCP) using a 33 design of experiment (DOE) to adjust the variables of the whitening treatment, and DOE analysis showed that time and hydrogen peroxide concentration do not have a significant effect on non-cellulosic remotion, unlike temperature. The behavior of this pulp in the production of viscose was compared against that of commercially available wood cellulose pulp (WCP). FCP showed a suitable cellulose content with a high degree of polymerization, which makes it a viable pulp for producing discontinuous viscose rayon filaments. Both pulps showed the same performance in the production of the viscose dope and the same chemical, thermal, and mechanical behavior after being regenerated.

Evaluation of Substances Released from Hydrothermal Pretreated Municipal Sludge and Performance of Hydrogen Production by the Corresponding Supernatant

2013 ◽  
Vol 726-731 ◽  
pp. 2468-2475 ◽  
Author(s):  
Li Yu ◽  
Cheng Lin Sun ◽  
Yong Hui Yu ◽  
Wen Tian Jiang
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Yield ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Production Potential ◽  
Reaction Conditions ◽  
Stirring Rate ◽  
And Performance ◽  
Temperature Time ◽  
Central Composite

Response surface methodology (RSM) with central composite design was adopted to investigate the optimum condition for carbohydrate released from hydrothermal pretreated sludge in an autoclave used for WAO (wet air oxidation). Temperature, time and stirring rate were chosen as variables. The maximum carbohydrate release (1356.8 mg/L) was estimated at the temperature of 161.2 °C, the time of 48 min and the stirring rate of 661 r/min. This statistical method could precisely optimize reaction conditions and predict the experimental data. Only 11.2 mL methane was generated with little hydrogen production of raw sludge. In contrast, hydrogen production potential of 25 mL was reached by using supernatant as substrate with a COD removal of 78.14%. Hydrogen yield was increased from 0.13 mL/g-VS (raw sludge) to 13.16 mL/g-VS (supernatant of pretreated sludge).

A study on some properties of thin biocomposites made from unbeaten wood and non-wood pulps

2012 ◽  
Vol 19 (3) ◽  
pp. 287-293
Author(s):  
Arif Karademir ◽  
Hulya Varlibas ◽  
Selim Karahan
Keyword(s):  
Short Fibers ◽  
Chemical Additives ◽  
Fine Content ◽  
Plant Fibers ◽  
Tensile Index ◽  
Density Values ◽  
Formation Method ◽  
Wood Pulps ◽  
Long Fibers ◽  
Sheet Sample

AbstractA number of thin biomaterials were prepared via a wet formation method from seven different unbeaten plant fibers without using any chemical additives. It is noted that sheets made with short fibers (Flax-B: 0.32 mm and Straw-UB: 0.36 mm) and high fine content (Flax-B: 9.77% and Straw-UB: 10.64%) showed higher tensile index values (Flax-B: 27 Nm/g and Straw-UB: 25 Nm/g) than those made from long fibers. Despite having the longest fibers (1.11 mm) in studied samples, the tensile index values of sheet sample made from Pine-S-UB was just 12 Nm/g, which is just half of short-fibered (0.36 mm) straw sheets. Air permeability of sheets made from Pine-S-UB and Straw-UB were 5322 and 917 ml/min, respectively. Densities of the same sheets in the same order were 493 and 539 kg/m3. It is concluded that long cellulose fibers actually produce bulky materials with limited interfiber contacting areas, while short ones give biocomposites with higher density values indicating a firmly compacted internal structure in the case of utilizing plant fibers without beating and refining. Results would be usable when producing biocomposites from plant fibers via wet formation followed by various resins and polymer moldings.

Morphology and enzyme histochemistry of dorsal muscles of the cat neck

1975 ◽  
Vol 38 (6) ◽  
pp. 1312-1321 ◽  
Author(s):  
F. J. Richmond ◽  
V. C. Abrahams
Keyword(s):  
Head Movement ◽  
Vertebral Column ◽  
Enzyme Histochemistry ◽  
Motor Nerve ◽  
Short Fibers ◽  
Major Function ◽  
Single Motor ◽  
Upper Cervical ◽  
Spinal Roots ◽  
Long Fibers

An examination has been made of the five dorsal muscles of the cat neck which insert into the lamboidal crest. The three larger muscles, splenius, biventer cervicis, and complexus, are characterized by the presence of tendinous inscriptions which serve as the insertion points of shorter muscle fibers which do not run the length of the muscle. Longer fibers are bound by the inscriptions and, thus can transmit tension developed by shorter fibers. These three muscles are multiply innervater by nerves emerging from upper cervical spinal roots. Multiple innervation is not associated with multiple end plates but with arrangement so that lower roots innervate a high proportion of short fibers and higher roots, a high proportion of long fibers. Occipitoscapularis and rectus capitis major are, by comparison, simple muscles, each with a single motor nerve. Of the muscles examined, occipitoscapularis alone does not have its origin on the vertebral column but on the scapula, and is unlikely to have any major function in head movement.

scholarly journals Effect of Environmental Tobacco Smoke on Children’s Anxiety and Behavior in Dental Clinics, Jeddah, Saudi Arabia: A Cross-Sectional Study

2021 ◽  
Vol 18 (1) ◽  
pp. 319
Author(s):  
Heba J. Sabbagh ◽  
Ghadeer Sharton ◽  
Jumana Almaghrabi ◽  
Manal Al-Malik ◽  
Mona Hassan Ahmed Hassan ◽  
...  
Keyword(s):  
Environmental Tobacco Smoke ◽  
Tobacco Smoke ◽  
Behavioral Problems ◽  
Rating Scale ◽  
Dental Anxiety ◽  
Cross Sectional Study ◽  
General Information ◽  
Cross Sectional ◽  
Linear Mode ◽  
And Behavior

Background: Environmental tobacco smoke (ETS) has been linked to behavioral problems, but no study has assessed its relationship with dental anxiety. Therefore, this study’s goal is to assess the relation between ETS and both behavioral problems and dental anxiety among children. Methods: The study sample was collected from two centres in Jeddah from October 2019 to January 2020. Inclusion criteria included healthy 5–16-year-old children having their first dental visit with no emergency complaint. The questionnaire including general information, ETS exposure, the child’s anxiety using the Abeer Children Dental Anxiety Scale (ACDAS) and dental behavior using the Frankl Behavioral Rating Scale. Results: Of 500 children, 337 (67.4% response rate) responded to the questionnaire, among whom 201 (59.6%) had been exposed to passive smoking compared to 136 (40.4%) who had not. Exposed children had a statistically significantly greater tendency to develop anxiety (p = 0.002) and demonstrate uncooperative behavior (p = 0.006). Generalized linear mode and binary regression analyses suggested that ETS has a statistically significant effect on children’s dental anxiety and behavior (p < 0.05). Conclusions: Children exposed to ETS demonstrated statistically significantly higher anxiety levels and uncooperative behavior in the dental clinic compared to those who were not exposed.

scholarly journals Biosynthesis of selenium nanoparticles using plant extracts

2021 ◽  
Author(s):  
Krystyna Pyrzynska ◽  
Aleksandra Sentkowska
Keyword(s):  
Green Synthesis ◽  
Plant Extracts ◽  
Reducing Agent ◽  
Selenium Nanoparticles ◽  
Synthesis Methods ◽  
Shape Stability ◽  
Plant Materials ◽  
Synthesis Conditions ◽  
Extract Concentration ◽  
Temperature Time

Abstract Selenium nanoparticles (SeNPs) have the potential to be used for various applications. Therefore, they have attracted more attention in recent years and several synthesis methods have been exploited. Green synthesis using plant extracts has gained popularity because it requires non-toxic solvents and moderate temperatures. Furthermore, it is environmentally friendly and uses a reducing agent that is easily accessible and biodegradable. In this review, we present recent reports concerning the capability of different plant materials for the biosynthesis of selenium nanoparticles. The synthesis conditions (temperature, time, selenium precursor, and extract concentration) are discussed in combination with the characteristics of the obtained product (composition, size, shape, stability). The application of synthesized selenium nanoparticles was briefly presented. Graphic abstract

scholarly journals SYNTHESIS OPTIMIZATION OF 6-NITRO-3,4-DIHYDROQUINAZOLINE-4-ONE

2020 ◽  
Vol 63 (7) ◽  
pp. 48-53
Author(s):  
Mirjalol E. Ziyadullaev ◽  
Rixsibay K. Karimov ◽  
Gulnora V. Zukhurova ◽  
Asqar Sh. Abdurazakov ◽  
Shamansur Sh. Sagdullaev
Keyword(s):  
13C Nmr Spectroscopy ◽  
Process Conditions ◽  
Mathematical Planning ◽  
Steep Ascent ◽  
Synthesis Conditions ◽  
Dinitro Derivative ◽  
Higher Temperature ◽  
Temperature Time ◽  
Main Factor

A method for the synthesis of the substance 6-nitro-3,4-dihydroquinazolin-4-one has been developed. Quantitative determination of the target product was carried out spectrophotometrically using an SF-46 instrument. As a solvent, 0.1 mol/l HCl was used. A 0.1 mol/l hydrochloric acid solution was used as a comparison solution. The optical density of the standard and test samples was measured at a wavelength of 254 nm. The synthesis conditions of 6-nitro-3,4-dihydro-quinazolin-4-one were studied. The structure of the obtained product was studied by IR, Mass, 1H, 13C NMR spectroscopy, and the structure of the synthesized compound was also established. The main factors that influence the process of producing 6-nitro-3,4-dihydroquinazolin-4-one are identified. The process is optimized by the method of mathematical planning of the experiment. A mathematical model is drawn up. And the regression equation is calculated. A steep ascent along the response surface was carried out and optimal process conditions were found: temperature, time, quantitative ratio of the starting materials. It has been established that the main factor affecting the nitration process of 3,4-dihydroquinazolin-4-one is the temperature of 40 ºC and the reaction time is 4.5 h. Note that at a higher temperature, according to the analysis, a significant amount of dinitro derivative is formed, as a reaction byproduct.   

scholarly journals USE OF PHARMACEUTICAL WASTE IN PAPER INDUSTRY OF THE REPUBLIC OF UZBEKISTAN

2020 ◽  
pp. 285-290
Author(s):  
Khalima Abishevna Babakhanova ◽  
Zulfija Kamilovna Galimova ◽  
Mansur Mekhridinovich Abdunazarov
Keyword(s):  
Paper Industry ◽  
Hot Water ◽  
Licorice Root ◽  
Paper Sheet ◽  
Short Fibers ◽  
High Quality ◽  
Pharmaceutical Waste ◽  
Naoh Solution ◽  
The Republic ◽  
Long Fibers

The article gives the consideration to the properties of paper with the addition of pulp mass from the waste of the pharmaceutical industry, namely licorice root after removing extraction. Licorice roots were dried to air-dry state after extraction, cleaned of wastes and cut into fragments 10–30 mm long, then subjected to pulping with 2–4% NaOH solution at a hydro module 1 : 5, at a temperature of 95–98 °С for 60–90 minutes. After washing with hot water, they are bleached in an alkaline medium with a solution of hydrogen peroxide at a consumption of 3–4% of the mass of absolutely dry cellulose, hydro module 1: 5, temperature 70–95 °C for 60–90 minutes. After washing, grinding to a gristing degree of ~60°ShR, prepared castings weighting 80–90 g/m2 on a leaf-casting mashine. Physical, mechanical and optical properties of experimental castings are determined. Revealed that the addition of malt mass of the cotton contributes  to the formation of dense orderly structures of the paper sheet, as short fibers of licorice filled the gaps between the long fibers of cotton pulp, thereby reducing the pore volume and reactive surface availability and receipt paper with the highest mechanical strength. Adding malt mass to cotton mass at a ratio of 10 : 2 is optimal, further replenishment contributes to an increase in sorption absorption, that is, to obtain paper with a porous structure, which is not desirable for high-quality reproduction.

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