scholarly journals The Effect of Salt Solutions and Absorption Cycles in the Capillary and Drying Coefficient of Red Brick Samples with Different Joints

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
A. S. Guimarães ◽  
J. M. P. Q. Delgado ◽  
V. P. de Freitas ◽  
A. P. Albuquerque
Keyword(s):  
Molecular Diffusion ◽  
Research Work ◽  
Sodium Sulphate ◽  
Capillary Absorption ◽  
Material Decomposition ◽  
Salt Solutions ◽  
Partial Immersion ◽  
First Order Kinetics ◽  
Building Components ◽  
Best Fit

Rising damp can reduce building’s aesthetical value, comfort, and health mark when combined with the existence of soluble salts in the building components and in the ground water can even lead to material decomposition and compromise its structural performance. This research work intended to study the effect of different absorption cycles of two saturated solutions of sodium sulphate and potassium chloride in the capillary absorption curves obtained through the partial immersion of red brick samples without and with different joints. The results revealed significant differences in the capillary coefficients obtained when samples were tested with salt solutions. In the end of this paper an evaluation of the drying kinetics was presented for all the tested samples. Four different first-order kinetics models, available in the literature, were adjusted to describe the drying process and the results point that the Page and Logarithmic models allow the best fit. The apparent molecular diffusion coefficient for solid red brick samples saturated with different solutions and joints was also estimated.

The Effect of Salt Solutions in the Capillarity Absorption Coefficient of Red Brick Samples

2016 ◽  
Vol 369 ◽  
pp. 168-172 ◽  
Author(s):  
A.S. Guimarães ◽  
J.M.P.Q. Delgado ◽  
T. Rego ◽  
V.P. de Freitas
Keyword(s):  
Sodium Sulphate ◽  
Structural Performance ◽  
Capillary Absorption ◽  
Historical Buildings ◽  
Material Decomposition ◽  
Salt Solutions ◽  
Porous Network ◽  
Partial Immersion ◽  
Salt Ions ◽  
Rising Damp

Rising damp is one of construction’s major problems associated with use of porous materials in this industry. This mechanism has a massive influence on the degradation of historical buildings since they were built in a time when construction technologies made no effort to prevent this kind of pathologies. The rising damp by itself can reduce the aesthetical value of the building and, when combined with the existence of soluble salts in the building and in the ground water can even lead to material decomposition and compromise the structural performance of the building. This happens due to the migration of the salt ions dissolved in water into the porous network of the building’s walls where they remain and crystalize after water evaporates, dealing great pressures against the pore walls and eventually resulting in their fracture after many cycles of crystallization/dissolution.The experimental work intended to study the effect of two different saturated solutions of sodium sulphate and potassium chloride in the capillary absorption curves obtained through the partial immersion of red brick samples. In the end of this paper there will be a macroscopic evaluation of the sample’s crystallized top surface, obtained after a partial drying period. The results revealed significant differences in the capillary coefficients obtained when samples were tested with salt solutions.

Drying Kinetics Evaluation of Solid Red Bricks

2015 ◽  
Vol 3 ◽  
pp. 119-134
Author(s):  
E. Barreira ◽  
J.M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Moisture Content ◽  
Molecular Diffusion ◽  
Moisture Transfer ◽  
Drying Kinetics ◽  
Drying Process ◽  
Drying Time ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Best Fit

Moisture is one of the most deteriorating factors of buildings. The moisture content depends on hygroscopic equilibrium between buildings materials and environment, which is determined by the drying and wetting rate of masonry. So, the moisture content is not only determined by the water that is absorbed by the material, but also by the amount of water that is evaporated under favourable conditions, which is described by the drying process.This work presents the results of an experimental evaluation of the drying kinetics of solid red brick, considering the bulk moisture transfer. The drying kinetics was assessed considering different environment conditions (air temperature and humidity). The experimental results showed that the drying flux is extremely dependent of temperature and relative humidity in the first stage of the drying process. The values obtained were between 0.025 kg/m2h (T=15oC and RH=80%) and 0.135 kg/m2h (T=30oC and RH=50%), for the worst and better drying ambient conditions.Different first-order kinetics models, available in the literature, were adjusted to describe the drying process and estimate the equilibrium moisture content of the samples. The results point that Midilli et al. model allows the best fit and that the drying time constant is strongly affected by the drying air conditions. It was also estimated the apparent molecular diffusion coefficient for solid red brick samples and its variation with temperature.

Sodium salt scaling in black liquor evaporators and the effects of the addition of tall oil brine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Erik Karlsson ◽  
Anders Åkesjö
Keyword(s):  
Sodium Carbonate ◽  
Sodium Salt ◽  
Black Liquor ◽  
Sodium Sulphate ◽  
Salt Solutions ◽  
Tall Oil ◽  
Sulphate Content ◽  
Inhibition Effect ◽  
Salt Scaling ◽  
Primary Nucleation

AbstractSodium salt scaling, i. e. the formation of doubles salts comprised of sodium, carbonate and sulphate on the heat transfer surfaces, is a common problem that occurs during black liquor evaporation. In this study, experimental results are presented that provide new insights into the formation and composition of such scales and how they are influenced by the addition of tall oil brine. It was found that increased content of sodium carbonate and sodium sulphate in the black liquor increased scaling, while the ratio between carbonate and sulphate had a lesser influence than reported in other studies. Black liquor created loose clay-like scales comprised of aggregated crystals and black liquor, whereas salt solutions created hard mineral-like scales. The scales formed by both the black liquor and the salt solution showed a tendency to fall off during formation after primary nucleation. It was also found that both tall oil soap and alkalized tall oil brine could inhibit the formation of scales. The inhibition effect is stronger if adding the soap or brine just before scaling starts, but also depends on the amount added, the sodium carbonate and sodium sulphate content in the liquor as well as other factors.

scholarly journals Palladium-Supported Zirconia-Based Catalytic Degradation of Rhodamine-B Dye from Wastewater

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1522
Author(s):  
Salma Jabeen ◽  
Muhammad Sufaid Khan ◽  
Rozina Khattak ◽  
Ivar Zekker ◽  
Juris Burlakovs ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rhodamine B ◽  
Dye Degradation ◽  
Freundlich Isotherm ◽  
Impregnation Method ◽  
K Value ◽  
First Order Kinetics ◽  
Good Catalytic Activity ◽  
Rhodamine B Dye ◽  
Best Fit

The catalytic activity of Pd/ZrO2 was studied in terms of the degradation of rhodamine-B dye in the presence of hydrogen peroxide. Pd/ZrO2 was prepared by impregnation method, calcined at 750 °C and characterized by XRD, SEM and EDX. The catalyst showed good catalytic activity for dye degradation at 333 K, using 0.05 g of the catalyst during 5 h. The reaction kinetics followed the pseudo-first order kinetics. The Freundlich, Langmuir and Temkin isotherms were applied to the data and the best fit was obtained with Freundlich isotherm. Thermodynamic parameters, like ΔH, ΔG and ΔS were also calculated. The negative values of ΔH (−291.406 KJ/mol) and Gibbs free energy (ΔG) showed the exothermic and spontaneous nature of the process. The positive ΔS (0.04832 KJ/mol K) value showed suitable affinity of catalyst for dye degradation. The catalyst was very stable, active and was easily separated from the reaction mixture by filtration. It can be concluded from the results that the prepared catalyst could be effectively used in dyes degradation/removal from water subjected to further validation and use for various dyes.

Unique Taxonomy for Evaluating Fog Computing Services

2021 ◽  
pp. 165-177
Author(s):  
Akashdeep Bhardwaj ◽  
Sam Goundar
Keyword(s):  
Fog Computing ◽  
Research Work ◽  
Cloud Service ◽  
Time Data ◽  
Computing Services ◽  
Last Mile ◽  
Technology Applications ◽  
Service Consumer ◽  
Cloud Network ◽  
Best Fit

Cloud computing has slowly but surely become the foremost service provider for information technology applications and platform delivery. However, Cloud issues continue to exist, like cyberattacks, slow last mile latency, and clouds lack client-centric and location-aware applications to process real time data for efficient and customized application delivery. As an alternative, Fog Computing has the potential to resolve these issues by extending the Cloud service provider's reach to the edge of the Cloud network model, right up to the Cloud service consumer. This enables a whole new state of applications and services which increases the security, enhances the cloud experience and keeps the data close to the user. This research article presents a review on the academic literature research work on Fog Computing, introduces a novel taxonomy to classify cloud products based on Fog computing elements and then determine the best fit Fog Computing product to choose for the Cloud service consumer.

scholarly journals Calibration of Manning’s roughness in non-instrumented rural basins using a distributed hydrological model

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 164-173
Author(s):  
Carlos Andrés Caro Camargo ◽  
Oscar Fabián Pacheco Merchán ◽  
Hans Paul Sánchez Tueros
Keyword(s):  
Hydrological Model ◽  
Numerical Study ◽  
Research Work ◽  
Roughness Coefficient ◽  
Distributed Hydrological Model ◽  
The Standard Model ◽  
Saint Venant Equations ◽  
Volume Method ◽  
Best Fit ◽  
Selection Of

The purpose of this research work was to calibrate the Manning's roughness coefficient in rural non-instrumented basins using a distributed hydrological model. The process consisted of the selection of several basins with vegetal cover of forests and grasslands, and its subsequent experimental numerical study, in which the hydrological response hydrograph of each reference basin was obtained from the HEC-HMS software and the hydrograph to be calibrated was the Iber software, which is a hydrodynamic model based on the two-dimensional Saint Venant equations, solved by the finite volume method. Once the calibration process was carried out, the roughness coefficients with the best fit for each basin were identified with increases in precipitation, identifying the limitations of these values and the standard model used.

Stability and Performance Study of Polyethersulfone Membranes Modified Using Polyelectrolytes

2013 ◽  
Vol 65 (4) ◽  
Author(s):  
Law Yong Ng ◽  
Abdul Wahab Mohammad ◽  
Ching Yin Ng ◽  
Nur Hanis Hayati Hairom
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Research Work ◽  
Performance Study ◽  
Salt Solutions ◽  
Cross Sectional ◽  
And Performance ◽  
Surface Modified ◽  
Lower Contact ◽  
Scanning Electron

In this research work, porous PES membranes were initially pre-heated for certain duration of time and then surface-modified to reject the MgSO4 salt solutions through self-adsorption of polyelectrolytes. From the experimental work, higher membrane salt rejection capability can be obtained when the number of polyelectrolyte bilayers is increased. The images of the cross-sectional morphology of modified and non-modified membranes were obtained using field emission scanning electron microscopy (FESEM). All modified membranes showed relatively lower contact angle values.

scholarly journals Studies of the large intestine of sheep

1982 ◽  
Vol 47 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R. M. Dixon ◽  
J. V. Nolan ◽  
L. P. Milligan
Keyword(s):  
Continuous Infusion ◽  
Solid Phase ◽  
Single Injection ◽  
Proximal Colon ◽  
First Order Kinetics ◽  
Tracer Techniques ◽  
Unbiased Estimates ◽  
Brome Grass ◽  
Kinetics Of ◽  
Best Fit

1. Experiments were undertaken to examine the errors associated with the use of indigestible markers, the 51Cr-labelled complex of chromium ethylenediaminetetra-acetic acid (51Cr-EDTA) and 103Ru-labelled tris-(1,10-phenanthroline)-ruthenium(II) chloride (103Ru-P), to measure liquid- and solid-phase digesta kinetics in the caecum and proximal colon of sheep.2. First-order kinetics of markers were observed following either single injection or termination of continuous infusion. There were no differences between the half-times (T½) of marker in the caecum plus proximal colon whether calculated from marker concentration in caecal digesta or in faeces. There were also no differences in the T½ values calculated for the liquid- and solid-phase markers. When pool sizes calculated from the marker kinetics were compared with the volume of digesta present in the caecum and proximal colon at slaughter, it appeared that the 51Cr-EDTA and 103Ru-P caecal pools described the digesta contained in the entire caecum and proximal colon.3. The flow-rates of dry matter (DM) through the caecum of sheep given 694 g lucerne (Medicago sativa) DM/d were similar whether estimated from total collection of faeces, by single injection of marker, or by the ratio, marker concentration: DM in either caecal digesta or faeces during continuous infusion of marker into either the rumen or the caecum.4. In sheep given 553 g brome grass (Bromus inermus) DM/d the coefficient of variation of estimates of the plateau of 51Cr-EDTA marker during continuous infusion into the caecum was greater when 130 ml infusate/d were administered than with 1000 ml/d.5. In the sheep given brome grass the lines of best fit of decline in In 51Cr-EDTA marker concentration v. time following termination of the continuous infusions described previously and following single injection of marker in 20 or 2 ml into the caecum were examined. The variation was least when 1000 ml infusate/d had been administered and was unacceptably large following a single injection of 2 ml.6. These experiments showed that tracer techniques could provide unbiased estimates of trace kinetics in the caecum and proximal colon.

scholarly journals Some Clarifications Regarding Literature on Atmospheric Corrosion of Weathering Steels

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
I. Díaz ◽  
H. Cano ◽  
B. Chico ◽  
D. de la Fuente ◽  
M. Morcillo
Keyword(s):  
Corrosion Rate ◽  
Environmental Conditions ◽  
Atmospheric Corrosion ◽  
Research Work ◽  
Rust Layer ◽  
Morphology And Structure ◽  
Time Of Wetness ◽  
Best Fit

Extensive research work has thrown light on the requisites for a protective rust layer to form on weathering steels (WSs) in the atmosphere, one of the most important is the existence of wet/dry cycling. However, the abundant literature on WS behaviour in different atmospheres can sometimes be confusing and lacks clear criteria regarding certain aspects that are addressed in the present paper. What corrosion models best fit the obtained data? How long does it take for the rust layer to stabilize? What is the morphology and structure of the protective rust layer? What is an acceptable corrosion rate for unpainted WS? What are the guideline environmental conditions, time of wetness (TOW), SO2, and Cl−, for unpainted WS? The paper makes a review of the bibliography on this issue.

Preliminary Results of the Use of Hydroxyapatite as a Consolidant for Carbonate Stones

2011 ◽  
Vol 1319 ◽  
Author(s):  
Enrico Sassoni ◽  
Sonia Naidu ◽  
George W. Scherer
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Dynamic Elastic Modulus ◽  
Capillary Absorption ◽  
Treatment Technique ◽  
Constant Weight ◽  
Lattice Match ◽  
Partial Immersion ◽  
Phase Characterization ◽  
Indiana Limestone

ABSTRACTThe effectiveness of using hydroxyapatite (HAP) as a consolidant for carbonate stones was evaluated. HAP was chosen as a consolidating agent since it is notably less soluble than calcite and has a similar crystal structure and a close lattice match to it. Among possible methods for forming HAP, the reaction between the calcite of the stone and a solution of diammonium hydrogen phosphate (DAP) in mild conditions was chosen. Indiana Limestone samples, artificially damaged by heating to 300°C for 1 hour, were treated with a 1 molar DAP solution by partial immersion and capillary absorption for 48 hours or by brushing until apparent refusal and wrapping with a plastic film for 48 hours. After washing in deionized water for 3 days and drying under a fan at room temperature until constant weight, the improvements in dynamic elastic modulus and tensile strength were evaluated. The formation of calcium phosphate phases was observed by scanning electron microscopy (SEM) and the phase characterization performed by energy dispersive X-ray spectroscopy (EDS) and electron back-scattered diffraction (EBSD). The water absorption modification after the consolidating treatment was then assessed. Results show that treated samples experienced significant increases in dynamic elastic modulus and tensile strength, as a consequence of crack reduction and pore filling consequent to HAP deposition at grain boundaries. The sorptivity of the treated samples is reduced by 26-44% (based on treatment technique), so that water and water vapor exchanges with the environment are not blocked.

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