scholarly journals Effect of the wavy tank wall on the characteristics of mechanical agitation in the presence of a Al2O3-water nanofluid

Author(s):  
Abderrahim Mokhefi ◽  
Mohamed Bouanini ◽  
Mohammed Elmir ◽  
Pierre Spitéri

The enhancement of the heat transfer in the stirred tank is a much-desired objective for accelerating certain physical and chemical parameters in the industrial field. From this basis, an attempt is made in this paper to investigate the effect of the wavy wall of a stirred tank on the hydrodynamic, thermal, and energetic behavior of an Al2O3-Water nanofluid. The stirred tank has a flat bottom, and it is equipped with an anchor stirrer. A hot temperature has been imposed on the tank wall, and the agitator has been assumed adiabatic, where the nanofluid has a cold temperature at the initial instant. The laminar flow was governed by the equations that describe the forced convection, and it was solved by the finite element method. The numerical simulation results showed a considerable acceleration in the heat transfer inside the stirred tank by increasing the amplitude of the wavy wall and increasing the nanoparticle concentration. However, there has been a remarkable increase in the stirring power number. This contribution aims to increase thermal efficiency, especially in the chemical and petrochemical fields, to obtain a better yield of certain chemical reactions and mass transfer depending on the heat.

Author(s):  
Janine Patricia Melo Oliveira ◽  
José Crisóstomo da Silva Neto ◽  
Adriano Sant’Ana Silva ◽  
Saulo Soares da Silva ◽  
Adriana da Silva Santos

<p>Este trabalho tem como objetivo produzir um fermentado alcoólico proveniente do suco de laranja <em>(Citrus sinensis), </em>segundo processo adaptado das metodologias já existentes para obtenção de outros fermentados de fruta. O processo produtivo do fermentado de laranja e as analises referentes ao mesmo foram conduzidos no Laboratório de Operações Unitárias e Fenômeno de Transporte do Centro de Ciências e Tecnologia Agroalimentar da Universidade de Campina Grande – Campus Pombal - Pb. Com relação às etapas da adição dos insumos na confecção do fermentado, as mesmas não foram feitas na ordem descrita pela maioria das literaturas que se trabalham com fermentados alcoólicos, onde a ordem seguida foi: Extração do mosto, Preparação do Mosto: Sulfitação, Inoculação do Microrganismo e Nutrientes, Determinação do °Brix, Chaptalização,<strong> </strong>Fermentação Alcoólica, Decantação e Trasfegas, Clarificação, Filtração e o Envase. Constata-se pelo presente trabalho que o fermentado de laranja, mostrou-se aceitável tanto em relação aos parametros físico-químicos analisados para o mesmo, quanto para as carcteristicas sensoriais, tal como o sabor, aroma e aparência. Reforça-se, portanto, a idéia de agregação de valor a uma matéria-prima consideravelmente nutricional, por meio da confecção de um produto inovador.</p><p align="center"><strong><em>Production of alcoholic fermented orange</em></strong></p><p><strong>Abstract</strong><strong>: </strong>This work aims to produce an alcoholic fermented from orange juice (Citrus sinensis), second process adapted from existing methodologies for obtaining other fermented fruit. The production process of fermented orange and the same related analyzes were conducted at the Unit Operations Laboratory and Phenomenon Transport Science Center and Agrifood Technology, University of Campina Grande - Campus Pombal. - Pb Regarding the steps to add inputs in the manufacture of fermented, they were not made in the order described by most of the literature that working with alcoholic fermentation, where the order was then: the must extraction, preparation of Mosto: Sulphitation, inoculation of the micro-organism and nutrients, determination of ° Brix , Chaptalisation, alcoholic fermentation, decantation, and Racking, clarification, filtration and Filling. It appears in this work that fermented orange, proved acceptable both for physical and chemical parameters analyzed for the same, as for the sensory carcteristicas, such as flavor, aroma and appearance. , Up reinforces therefore the value-added idea of a raw material considerably nutrition through the production of an innovative product.</p>


2018 ◽  
Vol 6 (10) ◽  
pp. 123-130
Author(s):  
Yaroslava Zhukova ◽  
◽  
Pylyp Petrov ◽  
Olena Boloba ◽  
Tetiana Ohrimenko ◽  
...  

2000 ◽  
Vol 31 (4-5) ◽  
pp. 411-422 ◽  
Author(s):  
Gísli Már Gíslason ◽  
Jón S. Ólafsson ◽  
Hákon Adalsteinsson

The characteristics of stream and river ecosystems in arctic and alpine areas are determined mainly by the relative contribution of glacial meltwater, snowmelt, rainfall and groundwater. Each source generates a particular seasonal hydrological signature, affecting physical and chemical properties, and hence biological communities. The relative contribution of each source is sensitive to climate change. The study was concentrated on the glacial River W-Jökulsá and some non-glacial rivers in the central highlands of Iceland. The water in the glacial river was entirely glacial meltwater at the glacier margin, but the glacial contribution was about 20% 40 km downstream. However, its tributaries and non-glacial reference rivers were mainly springfed. The invertebrate fauna was confined to Chironomidae of the genus Diamesa close to the glacier, but other taxa (species and groups of species) occupied the river further downstream, where their diversity was close to that found in the reference rivers.


1987 ◽  
Vol 52 (12) ◽  
pp. 2876-2885
Author(s):  
Milan Rylek ◽  
Petr Svoboda ◽  
Jiří Souček

The effect of hydrogenation conditions on rate of hydrogenation of rape seed oil was studied in a laboratory stirred tank reactor of 250 ml volume, with nickel on kieselguhr catalyst within the range of conditions (150 ⪬ t(°C) ⪬ 190), (0.1 ⪬ P(MPa) ⪬ 1.0), and (0.01 ⪬ cNi(%) ⪬ 0.37). On the basis of these results a comparison of the effect of a Venturi tube and single pipe gas inlet as gas distributors on hydrogenation rate was made in a bench scale unit of 5 l volume.


2021 ◽  
Vol 13 (5) ◽  
pp. 2590
Author(s):  
S. A. M. Mehryan ◽  
Kaamran Raahemifar ◽  
Leila Sasani Gargari ◽  
Ahmad Hajjar ◽  
Mohamad El Kadri ◽  
...  

A Nano-Encapsulated Phase-Change Material (NEPCM) suspension is made of nanoparticles containing a Phase Change Material in their core and dispersed in a fluid. These particles can contribute to thermal energy storage and heat transfer by their latent heat of phase change as moving with the host fluid. Thus, such novel nanoliquids are promising for applications in waste heat recovery and thermal energy storage systems. In the present research, the mixed convection of NEPCM suspensions was addressed in a wavy wall cavity containing a rotating solid cylinder. As the nanoparticles move with the liquid, they undergo a phase change and transfer the latent heat. The phase change of nanoparticles was considered as temperature-dependent heat capacity. The governing equations of mass, momentum, and energy conservation were presented as partial differential equations. Then, the governing equations were converted to a non-dimensional form to generalize the solution, and solved by the finite element method. The influence of control parameters such as volume concentration of nanoparticles, fusion temperature of nanoparticles, Stefan number, wall undulations number, and as well as the cylinder size, angular rotation, and thermal conductivities was addressed on the heat transfer in the enclosure. The wall undulation number induces a remarkable change in the Nusselt number. There are optimum fusion temperatures for nanoparticles, which could maximize the heat transfer rate. The increase of the latent heat of nanoparticles (a decline of Stefan number) boosts the heat transfer advantage of employing the phase change particles.


Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 221
Author(s):  
Rafał Tytus Bray ◽  
Katarzyna Jankowska ◽  
Eliza Kulbat ◽  
Aneta Łuczkiewicz ◽  
Aleksandra Sokołowska

The paper presents the results of research on the use of ultrafiltration, using membranes of 200 and 400 kDa separation, for disinfection of municipal treated wastewater. The research was conducted on a fractional technical scale using real municipal treated wastewater from two large wastewater treatment plants treating most of the wastewater over the one-million polycentric Gdańsk agglomeration (1.2 million inhabitants). UF 200 kDa and UF 400 kDa processes enabled further improvement of the physical and chemical parameters of treated wastewater. Total phosphorus (to below 0.2 mg/L–UF 200 kDa, 0.13 mg/L–UF 400 kDa) and turbid substances (to below 0.2 mg/L, both membranes) were removed in the highest degree. COD was reduced efficiently (to below 25.6 mgO2/L–UF 200 kDa, 26.8 mgO2/L–UF 400 kDa), while total nitrogen was removed to a small extent (to 7.12 mg/L–UF 200 kDa and 5.7 mg/L–UF 400 kDa. Based on the reduction of indicator bacteria; fecal coliforms including E. coli (FC) and fecal enterococci (FE) it was found that the ultrafiltration is an effective method of disinfection. Not much indicator bacterial were observed in the permeate after processes (UF 200 kDa; FC—5 CFU/L; FE—1 CFU/L and UF 400 kDa; FC—70 CFU/L; FE—10 CFU/L. However, microscopic analysis of prokaryotic cells and virus particles showed their presence after the application of both membrane types; TCN 3.0 × 102 cells/mL–UF 200 kDa, 5.0 × 103 cells/mL–UF 400 kDa, VP 1.0 × 105/mL. The presence of potentially pathogenic, highly infectious virus particles means that ultrafiltration cannot be considered a sufficient disinfection method for treated wastewater diverted for reuse or discharged from high load wastewater treatment plants to recreational areas. For full microbiological safety it would be advisable to apply an additional disinfection method (e.g., ozonation).


Environments ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 49
Author(s):  
Markéta Šourková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Magdalena Daria Vaverková

Illegal dumps and landfills with disposed of tires are a fact of today, which should not be neglected as they represent a great ecological burden for the environment, affect the surrounding nature and disturb the landscape. This research was focused on testing the phytotoxicity of aqueous leachates from the fractions of tires in two sets of experiments—to simulate laboratory conditions (tire leaching in distilled water) and natural conditions (tire leaching in water from a recipient) using the Phytotoxkit testing kit (kit for the establishment of inhibition/stimulation effect on the root development) and the watercress test of phytotoxicity (biological method for the assessment of leachate phytotoxicity). Plants whose seeds were selected for the test were watercress (Lepidium sativum L.) and white mustard (Sinapis alba L.). The aqueous leachate was tested for 38 weeks. During the experiment, physical and chemical parameters were measured at intervals of 14 days by the testing instrument HACH TEST KIT: electric conductivity (EC), amount of dissolved oxygen (LDO) and pH. Results of root growth inhibition (IR) on the seeds of Lepidium sativum L. and Sinapis alba L. exhibited values ranging from 11.73% to 47.74% in the tested samples. Results of germination index (GI) on the seeds of Lepidium sativum L. exhibited values below 66% in the tested samples, which indicated the leachate phytotoxicity. In spite of the fact that similar studies are tackling the acute toxicity of leachates from tires (particularly to algae, embryos and animals), this research brings complementary information in testing the acute phytotoxicity of tire leachates to higher plants.


Sign in / Sign up

Export Citation Format

Share Document