Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 995 )

2018 ( 1387 )

2017 ( 1314 )

2016 ( 1867 )

Custom range...

Search Results: 1 - 10 of 721854 matches for " A. M. El-Roudi "
All listed articles are free for downloading (OA Articles)
Page 1 /721854
Display every page Item
Evaluation of the Pozzolanic Activity of Sewage Sludge Ash
M. A. Tantawy,A. M. El-Roudi,Elham M. Abdalla,M. A. Abdelzaher
ISRN Chemical Engineering , 2012, DOI: 10.5402/2012/487037
Fire Resistance of Sewage Sludge Ash Blended Cement Pastes
M. A. Tantawy,A. M. El-Roudi,Elham M. Abdalla,M. A. Abdelzaher
Journal of Engineering , 2013, DOI: 10.1155/2013/361582
Abstract: The aim of the present study is to investigate the hydration characteristics and the fire resistance of sewage sludge ash blended cement pastes by the determination of compressive strength, bulk density, and total porosity in addition to XRD and SEM techniques. Sewage sludge ash modifies the hydration of cement because of its pozzolanic reaction with portlandite favoring the formation of crosslinked fibrous calcium silicate of low Ca/Si ratio. Hence, it was concluded that thermal damage of cement pastes after the exposure to high treatment temperatures (i.e., crack formation and loss of mechanical properties) was effectively reduced with sewage sludge as content up to 20?wt% because of that the presence of crosslinked fibrous calcium silicate strengthens the cement matrix. 1. Introduction Sewage water is the collection of wastewater effluents from domestic, hospital, commercial, and industrial establishments. The objective of the sewage treatment is to produce treated sewage water and sewage sludge suitable for safe discharge into the environment or reuse [1]. International environmental protection agencies recommended that incineration is an attractive disposal method of sewage sludge [2]. Sewage sludge ash has been used as an additive in the production of construction materials [3], mortars [4], and concrete [5]. The exposure of concrete to high temperatures as in an accidental fire of buildings leads to an undesirable structural quality deterioration [6]. Previous studies illustrate that hardened cement paste plays a key role in high temperatures deterioration process. The main damage mechanisms that discuss the deterioration of concrete at elevated temperatures are thermal mismatch, decomposition of hydrates, coarsening of pore structure, and pore pressure effects [7]. Siliceous aggregates expand around 575°C as a result of the α-β quartz inversion, whereas cement paste shrinks above 200°C [8]. This thermal mismatch (i.e., expansion of siliceous aggregate and shrinkage of cement paste matrix) causes a considerable tension at the aggregate-matrix interface leading eventually to interface fracture and cracking [9]. The decomposition of hydrates occurs during the thermal damage of cementitious materials including the decomposition of ettringite, C-S-H, and carboaluminate hydrates at 180–450°C and portlandite at 425–580°C [10]. The decomposition of portlandite damages the C-S-H. The decomposition of hydrates decreases stiffness and strength of cementitious materials. Volume reduction of the hydrated phases because of the loss of bound water leads to air
Evaluation of the Pozzolanic Activity of Sewage Sludge Ash
M. A. Tantawy,A. M. El-Roudi,Elham M. Abdalla,M. A. Abdelzaher
ISRN Chemical Engineering , 2012, DOI: 10.5402/2012/487037
Abstract: Raw sewage sludge was characterized by XRD, FTIR, SEM, and TGA techniques and incinerated in temperature range 650–950°C for 2?h. The effect of incineration temperature on the microstructure and pozzolanic activity of the resultant ash was investigated by techniques mentioned above as well as Chapelle test. It was concluded that incineration of sewage sludge affects the microstructure and pozzolanic activity of the resultant ash. During incineration at temperatures lower than 800°C, amorphous silica captures fixed carbon resulting from incomplete combustion conditions whereas at higher temperatures crystallization of amorphous silica was enhanced. Hydration products formed from hydrothermal treatment of silica fume with lime is amorphous whereas that of sewage sludge ash is fibrous. Hence, incineration of sewage sludge ash must be optimized at 800°C to preserve the pozzolanic activity of the resultant ash. 1. Introduction Sewage is the collection of wastewater effluents from domestic, hospital, commercial, industrial establishments, and rain water. The objective of sewage treatment is to produce treated sewage water and sewage sludge suitable for safe discharge into the environment or reuse [1]. The most common treatment options for sewage sludge include anaerobic digestion, aerobic digestion, and composting. Choice of the treatment method depends on the amount of sludge and other site-specific conditions [2]. Sewage sludge tends to accumulate heavy metals existing in the wastewater. The composition of sewage sludge and its content of heavy metals vary widely depending on the sludge origins and treatment options [3]. In past decades, sewage sludge was primarily disposed to landfills and seawaters [4]. Space limitations on existing landfills and increasing environmental concerns such as groundwater pollution from landfill leachate, odor emission and soil contamination have prompted the investigation of alternative disposal routes [5]. Sewage sludge has been used in agriculture as fertilizer and soil amendment [6]. However heavy metals such as Zn, Cu, Ni, Cd, Pb, Hg, and Cr are principal elements restricting the use of sludge for agricultural purposes [3]. The solidification/stabilization of sewage sludge in cementitious matrix has been evaluated [7]. Sewage sludge adversely affects durability of concrete, mainly due to the organic material which retards setting and heavy metals which interfere with the hardening reactions [8]. Hence, sewage sludge addition in concrete was limited to 10?wt.% and the solidified concrete was recommended for use in certain
Using of Ground Penetrating Radar (GPR) and Sediment Cores as Method Interpretation of Sedimentary Environments the Estuaries of Northern West Oman Sea
M. Ahrari Roudi,R. Moussavi-Harami,R. Lak,A. Mahboubi
Research Journal of Environmental and Earth Sciences , 2012,
Abstract: The study area on the North West Coast of Oman Sea in Shoor and Parak estuaries is located within the city limits Chabahar. The GPR and seismic profiles in order to prepare and investigate the effects of subsurface and all is done. Identification of shallow subsurface structures material and thickness of the different are due to the contrast in electrical properties such as electrical conductivity and can pass including targets that are GPR detection methods are available. In this study the GPR profiles were taken with Mala GPR model. In order to calibrate the seismic data with characteristics facies obtained using a Euger involves two cores to lengths of 4.35 and 5 m were prepared. The data from these two methods were compared and the conclusions. The study showed that the cores are composed of two sedimentary facies. The first facies set includes mud with brown color and gravelly sandy mud facies with brownish cream color that the sedimentary environment is supratidal and the second facies set consists of muddy sand, gravelly mud and slightly gravelly sandy mud with gray color that specificities are related to depositional environment intertidal. Profile of the Shoor estuary defines four distinct facies that they are consistent with the core facies show up the upper facies set in the environment are supratidal and in the northeast of the South West on their thickness increases. The lower facies set environments intertidal formed that of the northeast toward the South West their thickness is unchanged. Profile of the Parak estuary defines two distinct facies that they are consistent with the core facies show up the upper facies set in the environment are supratidal that of the northeast toward the South West their thickness increases. The lower facies environments intertidal formed that of the northeast toward the South West their thickness does not change much. Since, the profile GPR No. 73 and 74 was nearer to the sea and influence the saltwater sea on penetration depth GPR is higher, detection of subsurface structures is less effective and two layers of subsurface has been identified in the parak estuary, but in Shoor estuary (the profile GPR No. 71 and 72), high distance from the sea and influence the saltwater sea on penetration depth GPR is less and detection of subsurface structures is better that has leading to the identification of four layers of subsurface. On the other hand comparison of sediment cores and GPR profiles with curve changes in global sea levels show that During two-Interval from time 2100 to 2800 years ago and so from time 4900
Isolation, Biochemical Characterization and DNA Identification of Yogurt Starters Streptococcus thermophilus & Lactobacillus delbrueckii ssp. bulgaricus in Gaza Strip  [PDF]
Kamal E. M. El Kahlout, Ismail M. El Quqa, Mahmoud W. El Hindi, Tarek A. El Bashiti
Advances in Microbiology (AiM) , 2018, DOI: 10.4236/aim.2018.812068
Abstract: Background: Milk is a healthy human nutrient, which is fermented to yogurt by lactic acid bacteria, mainly Streptococcus salivarius ssp, thermophilus and Lactobacillus. delbrueckii ssp. bulgaricus. This study aimed to isolate thermophilic starter bacteria from homemade yogurt made in Gaza Strip. The study sought to define both the biochemical and molecular characteristics of the isolated bacteria. Results: Three of the isolates were identified as Streptococcus thermophiles while two isolates were recognized as Lactobacillus delbrueckii ssp. bulgaricus. All five identified isolates showed worthy acidification capacity. Based on these characters, strains were applied for making yogurt either as single pure cultures or as mixed cultures. When using mixed cultures from S. thermophiles and L. bulgaricus, all tested combinations showed positive results. Conclusion: Isolated strains showed remarkable biotechnological characters. The isolates are expected to stimulate and improve quality of the yogurt when they are used as mixed starter cultures.
Geochemical Siliceous and Silicified Facies of Phosphate Series of Ouled Abdoun Basin (Morocco)  [PDF]
H. El Haddi, A. Benbouziane, M. Mouflih
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.47022

Syn-sedimentary post-diagenetic phenomena are remarkable in Moroccan phosphates. Indeed they are reference deposits for geological study, where important interests are given of determination and identification of these geochemical phenomena. Silicification is one of the phenomena that we have studied to determine the diagenetic processes that control the new-formation of silica in phosphate series of Ouled Abdoun. This study was performed on deposit EL Halassa, which belongs to the Ouled Abdoun Basin; they spread out the Maastrichtian to Lutetian. At first, petrographic approach was applied on different terms composing the phosphate series. In a second step, a geochemical approach on the same silica and silicified facies of phosphate series Ouled Abdoun Basin for characterizing silicification deduced the probable links between this diagenetic phenomenon and facies and forms’ affect. Ten major trace elements were measured. According to the phases’ petrographic relationship, the results were presented and discussed: silicate phase, the carbonate phase and clay phase.

On the Real Einstein Beauty E = Kmc2  [PDF]
A. J. Babchin, M. S. El Naschie
World Journal of Condensed Matter Physics (WJCMP) , 2016, DOI: 10.4236/wjcmp.2016.61001
Abstract: The paper suggests that E = mc2 may be open to misinterpretation and that in this form it is not what Einstein advanced first. It is further suggested to return to the slightly less compact formula E = Kmc2 where a < K < 1 which has the merit of accounting for the measured ordinary energy density of the cosmos (K = 1/22) and the conjectured missing dark energy density of the universe (K = 21/22) from the view point of economical notation.
Artificial Neural Networks Based Integrated Predictive Modelling of Quality Characteristics in CNC Turning of Cantilever Bars  [PDF]
D. M. Davakan, A. El Ouafi
World Journal of Mechanics (WJM) , 2017, DOI: 10.4236/wjm.2017.75013
Abstract: The objective of this study is to develop an effective approach for product quality prediction in Computer Numerical Control turning of cantilever bars. A systematic predictive modelling procedure based on experimental investigations, neural network modelling and various statistical analysis tools is designed to produce the most accurate, practical and cost-effective prediction model. The modeling procedure begins by exploring the relationships between cutting parameters known to have an influence on quality characteristics of machined parts, such as dimensional errors, form errors and surface roughness, as well as their sensitivity to the process conditions. Based on these explorations and using numerous statistical tools, the most relevant variables to include in the prediction model are identified and fused using several artificial neural network architectures. An application on CNC turning of cantilever bars demonstrates that the proposed modeling procedure can be effectively and advantageously applied to quality characteristics prediction due to its simplicity, accuracy and efficiency. The experimental validation reveals that the resulting prediction model can correctly predict the quality characteristics of machined parts under variable machining conditions.
Sentinel-1 Radar Data Assessment to Estimate Crop Water Stress  [PDF]
M. A. El-Shirbeny, K. Abutaleb
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.52B006
Water is an important component in agricultural production for both yield quantity and quality. Although all weather conditions are driving factors in the agricultural sector, the precipitation in rainfed agriculture is the most limiting weather parameter. Water deficit may occur continuously over the total growing period or during any particular growth stage of the crop. Optical remote sensing is very useful but, in cloudy days it becomes useless. Radar penetrates the cloud and collects information through the backscattering data. Normalized Difference Vegetation Index (NDVI) was extracted from Landsat 8 satellite data and used to calculate Crop Coefficient (Kc). The FAO-Penman-Monteith equation was used to calculate reference evapotranspiration (ETo). NDVI and Land Surface Temperature (LST) were calculated from satellite data and integrated with air temperature measurements to estimate Crop Water Stress Index (CWSI). Then, both CWSI and potential crop evapotranspiration (ETc) were used to calculate actual evapotranspiration (ETa). Sentinel-1 radar data were calibrated using SNAP software. The relation between backscattering (dB) and CWSI was an inverse relationship and R2 was as high as 0.82.
Some Factors Affecting the Production of Carotenoids by Rhodotorula glutinis var. glutinis  [PDF]
Amr A. El-Banna, Amal M. Abd El-Razek, Ahmed R. El-Mahdy
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.31011
Abstract: A new yeast strain isolated from pin cushion flower (Scabiosa atropurpura) in our laboratory was selected from 200 yeast isolates as carotenoids producer and identified as Rhodotorula glutinis var. glutinis. The selected isolate was grown in synthetic medium to study the effect of carbon to nitrogen ratio, sources of nitrogen and carbon, mineral salts and incubation temperature on carotenoids production. The results indicated the following optimal conditions: carbon to nitrogen ratio of 5, ammonium sulphate as nitrogen source, sucrose as carbon source, presence of zinc sulphate in the medium and cultivation temperature of 25?C. The studied factors affected the dry biomass as well as the proportion of carotenoids and consequently the colour of pellets of the yeast. The yeast strain was grown under the optimal conditions to study the changes occurring in the medium and the pellets during carotenoids production for 6 days. Carotenoids production started after the first day of incubation and most of the carotenoids content in the yeast cells was produced during stationary phase. The highest cellular (861 μg?g–1) and volumetric (1.9 mg?L–1) carotenoids content were ob- tained after 5 days of growth.
Page 1 /721854
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.