Search results for: under remed bulb . sand

Authors: Mustafa Col, Funda Gul Koc, Merve Yangaz, Eylem Subasi, Can Akbasoglu

Abstract:

G38NiCrMo8-4-4 steel is widely used in mining industries, machine parts, gears due to its high strength and toughness properties. In this study, microstructure, wear and mechanical properties of G38NiCrMo8-4-4 steel modified with boron used in the mining industry were investigated. For this purpose, cast materials were alloyed by melting in an induction furnace to include boron with the rates of 0 ppm, 15 ppm, and 50 ppm (wt.) and were formed in the dimensions of 150x200x150 mm by casting into the sand mould. Homogenization heat treatment was applied to the specimens at 1150˚C for 7 hours. Then all specimens were austenitized at 930˚C for 1 hour, quenched in the polymer solution and tempered at 650˚C for 1 hour. Microstructures of the specimens were investigated by using light microscope and SEM to determine the effect of boron and heat treatment conditions. Changes in microstructure properties and material hardness were obtained due to increasing boron content and heat treatment conditions after microstructure investigations and hardness tests. Wear tests were carried out using a pin-on-disc tribometer under dry sliding conditions. Charpy V notch impact test was performed to determine the toughness properties of the specimens. Fracture and worn surfaces were investigated with scanning electron microscope (SEM). The results show that boron element has a positive effect on the hardness and wear properties of G38NiCrMo8-4-4 steel.

Keywords: G38NiCrMo8-4-4 steel, boron, heat treatment, microstructure, wear, mechanical properties

Procedia PDF Downloads 195

Authors: Anthony El Hachem, Hosam Salman

Abstract:

Selecting the most effective construction method for drilled shafts under the high phreatic surface can be a challenging task that requires effective communication between the design and construction teams. Slurry placement, temporary casing, and permanent casing are the three most commonly used installation techniques to ensure the stability of the drilled hole before casting the concrete. Each one of these methods has its implications on the installation and performance of the drilled piers. Drilled shafts were designed to support a fire wall for an Energy project in Central Texas. The subsurface consisted of interlayers of sands and clays of varying shear strengths. The design recommended that the shafts be installed with temporary casing or slurry displacement due to the anticipated groundwater seepage through granular soils. During the foundation construction, it was very difficult to maintain the stability of the hole, and the contractor requested to install the shafts using permanent casings. Therefore, the foundation design was modified to ensure that the cased shafts achieve the required load capacity. Effective and continuous communications between the owner, contractor and design team during field shaft installations to mitigate the unforeseen challenges helped the team to successfully complete the project.

Keywords: construction challenges, deep foundations, drilled shafts, loose sands underwater table, permanent casing

Procedia PDF Downloads 193

Authors: Samiha Ramdani, Abdelhamid Geuttala

Abstract:

There is no doubt that the batteries increasingly used tires create environmental concerns. Algeria generates large amounts of by industrial and household waste, such as used tires and colored glass bottles and dishes, whose valuation in cementitious materials could be an interesting ecological and economical alternative for broadening eliminating cumbersome landfills. This work is a contribution to the promotion of local materials with the use of waste tires and glass bottle in the development of a new cementitious composite having the acceptable compressive strength and a capacity of improved strains. For this purpose, rubber crumb (GC) from shredding used tires were used as partial replacement of quarry sand with 10%, 20%, 40, 60%. In addition, some mixtures also contain glass powder at15% cement replacement by volume. The compressive strength, tensile strength, deformability, the water permeability and penetration Inions chlorides are studied. As results; an acceptable compressive strength was obtained with the substitution rate of 10% and 20% by volume, the deformability of the composite increases with increased replacement rate. The addition of finely ground glass as a partial replacement of cement concrete increases the resistance to penetration of Inions chloride and reduce the water permeability thereof; then increases their durability.

Keywords: crumb rubber, deformability, compressive strength, finely ground glass, durability, behavior law

Procedia PDF Downloads 321

Authors: Rowshan Mamtaz, Shuvo Ahmed, Imran Noor, Sumaiya Rahman, Prithvi Shams, Fahmida Gulshan

Abstract:

Last few decades have witnessed a phenomenal rise in the use of electrical and electronic equipment globally in our everyday life. As these items reach the end of their lifecycle, they turn into e-wastes and contribute to the waste stream. Bangladesh, in conformity with the global trend and due to its ongoing rapid growth, is also using electronics-based appliances and equipment at an increasing rate. This has caused a corresponding increase in the generation of e-wastes. Bangladesh is a developing country; its overall waste management system, is not yet efficient, nor is it environmentally sustainable. Most of its solid wastes are disposed of in a crude way at dumping sites. Addition of e-wastes, which often contain toxic heavy metals, into its waste stream has made the situation more difficult and challenging. Assessment of generation of e-wastes is an important step towards addressing the challenges posed by e-wastes, setting targets, and identifying the best practices for their management. Understanding and proper management of e-wastes is a stated item of the Sustainable Development Goals (SDG) campaign, and Bangladesh is committed to fulfilling it. A better understanding and availability of reliable baseline data on e-wastes will help in preventing illegal dumping, promote recycling, and create jobs in the recycling sectors and thus facilitate sustainable e-waste management. With this objective in mind, the present study has attempted to estimate the amount of e-wastes and its future generation trend in Bangladesh. To achieve this, sales data on eight selected electrical and electronic products (TV, Refrigerator, Fan, Mobile phone, Computer, IT equipment, CFL (Compact Fluorescent Lamp) bulbs, and Air Conditioner) have been collected from different sources. Primary and secondary data on the collection, recycling, and disposal of the e-wastes have also been gathered by questionnaire survey, field visits, interviews, and formal and informal meetings with the stakeholders. Material Flow Analysis (MFA) method has been applied, and mathematical models have been developed in the present study to estimate e-waste amounts and their future trends up to the year 2035 for the eight selected electrical and electronic equipment. End of life (EOL) method is adopted in the estimation. Model inputs are products’ annual sale/import data, past and future sales data, and average life span. From the model outputs, it is estimated that the generation of e-wastes in Bangladesh in 2018 is 0.40 million tons and by 2035 the amount will be 4.62 million tons with an average annual growth rate of 20%. Among the eight selected products, the number of e-wastes generated from seven products are increasing whereas only one product, CFL bulb, showed a decreasing trend of waste generation. The average growth rate of e-waste from TV sets is the highest (28%) while those from Fans and IT equipment are the lowest (11%). Field surveys conducted in the e-waste recycling sector also revealed that every year around 0.0133 million tons of e-wastes enter into the recycling business in Bangladesh which may increase in the near future.

Keywords: Bangladesh, end of life, e-waste, material flow analysis

Procedia PDF Downloads 198

Authors: Mohammed Mashrei

Abstract:

Ferrocement is a type of thin reinforced concrete made of cement-sand matrix with closely spaced relatively small diameter wire meshes, with or without steel bars of small diameter called skeletal steel. This work concerns on the behavior of square ferrocement slabs of dimensions (500) mm x (500) mm and 30 mm subjected to a central load. This study includes testing thirteen ferrocement slabs. The main variables considered in the experimental work are the number of wire mesh layers, percentage of silica fume and the presence of steel fiber. The effects of these variables on the behavior and load carrying capacity of tested slabs under central load were investigated. From the experimental results, it is found that by increasing the percentage of silica fume from (0 to 1.5, 3, 4.5 and 6) of weight of cement the ultimate loads are affected. Also From this study, it is observed that the load carrying capacity increases with the presence of steel fiber reinforcement, the ductility is high in the case of steel fibers. The increasing wire mesh layer from six to ten layers increased the load capacity by 76%. Also, a reduction in width of crack with increasing in number of cracks in the samples that content on steel fibers comparing with samples without steel fibers was observed from the results.

Keywords: ferrocement, fibre, silica fume, slab, strength

Procedia PDF Downloads 235

Authors: Ahmed T. Farid, Khaled Z. Soliman

Abstract:

Due to limited areas and excessive cost of land for projects, backfilling process has become necessary. Also, backfilling will be done to overcome the un-leveling depths or raising levels of site construction, especially near the sea region. Therefore, backfilling soil materials used under the foundation of structures should be investigated regarding its effect on ground motion characteristics, especially at regions subjected to earthquakes. In this research, 60-meter thickness of sandy fill material was used above a fixed 240-meter of natural clayey soil underlying by rock formation to predict the modified ground motion characteristics effect at the foundation level. Comparison between the effect of using three different situations of fill material compaction on the recorded earthquake is studied, i.e. peak ground acceleration, time history, and spectra acceleration values. The three different densities of the compacted fill material used in the study were very loose, medium dense and very dense sand deposits, respectively. Shake computer program was used to perform this study. Strong earthquake records, with Peak Ground Acceleration (PGA) of 0.35 g, were used in the analysis. It was found that, higher compaction of fill material thickness has a significant effect on eliminating the earthquake ground motion properties at surface layer of fill material, near foundation level. It is recommended to consider the fill material characteristics in the design of foundations subjected to seismic motions. Future studies should be analyzed for different fill and natural soil deposits for different seismic conditions.

Keywords: acceleration, backfill, earthquake, soil, PGA

Procedia PDF Downloads 380

Authors: Theophilus Asante, Comfort Nyarko, Daniel Antwi

Abstract:

Drug-resistant tuberculosis, together with the associated comorbidities like pulmonary fibrosis and silicosis, has been one of the most serious global public health threats that requires immediate action to curb or mitigate it. This prolongs hospital stays, increases the cost of medication, and increases the death toll recorded annually. Crinum asiaticum bulb (CAE) and betulin (BET) are known for their biological and pharmacological effects. Pharmacological effects reported on CAE include antimicrobial, anti-inflammatory, anti-pyretic, anti-analgesic, and anti-cancer effects. Betulin has exhibited a multitude of powerful pharmacological properties ranging from antitumor, anti-inflammatory, anti-parasitic, anti-microbial, and anti-viral activities. This work sought to investigate the anti-tuberculosis and resistant modulatory effects and also assess their effects on mitigating pulmonary fibrosis and silicosis. In the anti-tuberculosis and resistant modulatory effects, both CAE and BET showed strong antimicrobial activities (31.25 ≤ MIC ≤ 500) µg/ml against the studied microorganisms and also produced significant anti-efflux pump and biofilm inhibitory effects (ρ < 0.0001) as well as exhibiting resistance modulatory and synergistic effects when combined with standard antibiotics. Crinum asiaticum bulbs extract and betulin were shown to possess anti-pulmonary fibrosis effects. There was an increased survival rate in the CAE and BET treatment groups compared to the BLM-induced group. There was a marked decrease in the levels of hydroxyproline and collagen I and III in the CAE and BET treatment groups compared to the BLM-treated group. The treatment groups of CAE and BET significantly downregulated the levels of pro-fibrotic and pro-inflammatory cytokine concentrations such as TGF-β1, MMP9, IL-6, IL-1β and TNF-alpha compared to an increase in the BLM-treated groups. The histological findings of the lungs suggested the curative effects of CAE and BET following BLM-induced pulmonary fibrosis in mice. The study showed improved lung functions with a wide focal area of viable alveolar spaces and few collagen fibers deposition on the lungs of the treatment groups. In the anti-silicosis and pulmonoprotective effects of CAE and BET, the levels of NF-κB, TNF-α, IL-1β, IL-6 and hydroxyproline, collagen types I and III were significantly reduced by CAE and BET (ρ < 0.0001). Both CAE and BET significantly (ρ < 0.0001) inhibited the levels of hydroxyproline, collagen I and III when compared with the negative control group. On BALF biomarkers such as macrophages, lymphocytes, monocytes, and neutrophils, CAE and BET were able to reduce their levels significantly (ρ < 0.0001). The CAE and BET were examined for anti-oxidant activity and shown to raise the levels of catalase (CAT) and superoxide dismutase (SOD) while lowering the level of malondialdehyde (MDA). There was an improvement in lung function when lung tissues were examined histologically. Crinum asiaticum bulbs extract and betulin were discovered to exhibit anti-tubercular and resistance-modulatory properties, as well as the capacity to minimize TB comorbidities such as pulmonary fibrosis and silicosis. In addition, CAE and BET may act as protective mechanisms, facilitating the preservation of the lung's physiological integrity. The outcomes of this study might pave the way for the development of leads for producing single medications for the management of drug-resistant tuberculosis and its accompanying comorbidities.

Keywords: fibrosis, crinum, tuberculosis, antiinflammation, drug resistant

Procedia PDF Downloads 83

Authors: Bashar Tarawneh, Yasser Hakam

Abstract:

Rapid Impact Compaction (RIC) is a modern dynamic compaction device mainly used to compact sandy soils, where silt and clay contents are low. The device uses the piling hammer technology to increase the bearing capacity of soils through controlled impacts. The RIC device uses "controlled impact compaction" of the ground using a 9-ton hammer dropped from the height between 0.3 m to 1.2 m onto a 1.5 m diameter steel patent foot. The delivered energy is about 26,487 to 105,948 Joules per drop. To evaluate the performance of this technique, three project sites in the United Arab Emirates were improved using RIC. In those sites, a loose to very loose fine to medium sand was encountered at a depth ranging from 1.0m to 4.0m below the ground level. To evaluate the performance of the RIC, Cone Penetration Tests (CPT) were carried out before and after improvement. Also, load tests were carried out post-RIC work to assess the settlements and bearing capacity. The soil was improved to a depth of about 5.0m below the ground level depending on the CPT friction ratio (the ratio between sleeve friction and tip resistance). CPT tip resistance was significantly increased post ground improvement work. Load tests showed enhancement in the soil bearing capacity and reduction in the potential settlements. This study demonstrates the successful application of the RIC for middle-deep improvement and compaction of the ground. Foundation design criteria were achieved in all site post-RIC work.

Keywords: compaction, RIC, ground improvement, CPT

Procedia PDF Downloads 365

Authors: Zegrar Ahmed, Ghabi Mohamed

Abstract:

The degradation of arid and semi-arid ecosystems in Algeria has become a palpable fact that only hinders progress and rural development. In these exceptionally fragile environments, the decline of vegetation is done according to an alarming increase and wind erosion dominates. The ecosystem is subjected to a long hot dry season and low annual average rainfall. The urgency of the fight against desertification is imposed by the very nature of the process that tends to self-accelerate, resulting when human intervention is not forthcoming the irreversibility situations, preventing any possibility of restoration state of these zones. These phenomena have led to different degradation processes, such as the destruction of vegetation, soil erosion, and deterioration of the physical environment. In this study, the work is mainly based on the criteria for classification and identification of physical parameters for spatial analysis and multi-sources to determine the vulnerability of major steppe formations and their impact on desertification. we used Landsat data with two different dates March 2010 and November 2014 in order to determine the changes in land cover, sand moving and land degradation for the diagnosis of the desertification Phenomenon. The application, through specific processes, including the supervised classification was used to characterize the main steppe formations. An analysis of the vulnerability of plant communities was conducted to assign weights and identify areas most susceptible to desertification. Vegetation indices are used to characterize the steppe formations to determine changes in land use.

Keywords: remote sensing, SIG, ecosystem, degradation, desertification

Procedia PDF Downloads 339

Authors: Mohamed Eltarabily, Abdelazim Negm, Chihiro Yoshimura

Abstract:

Recently, the pollution of groundwater from the use of nitrogenous fertilizer is at the increase. Also, due to the increase in area under cultivation and regular use of fertilizer in irrigated agriculture, groundwater pollution from agricultural activities is becoming a major concern. Because of the high mobility of Nitrate (NO3-) in soil which is governed by electrostatic processes, particularly anion exclusion, nitrate can be intercepted by shallow subsurface drainage pipe systems and then discharged offsite into streams, rivers, and lakes causing many hazards. In order to solve these environmental problems associated with nitrate, a better understanding of how NO3- moves through the soil profile under flow conditions is required. In the present paper, the results of a comparative study between experimental and numerical modeling of Nitrate transport through a saturated soil column are presented and analyzed. In order to achieve that, three water fluxes densities; 0.008, 0.007, and 0.006 m sec-1 and N concentration rates 10 mol cm-3 were used. The same concentrations were used in the simulation using HYDRUS-2D. The physical and chemical properties of the collected soil samples were calculated. Besides, the soil texture was determined which was silty sand. Results showed that HYDRUS-2D can successfully predict the relative behavior of N transport in the present experiment. Nitrate concentrations will reach deeper depth with the increase in the water flux. Overall, it was overestimated in the final concentration of (NO3-) in the soil by numerical simulation than by experimental column test. The column experiment is a useful tool for assessing the nitrate concentrations in the soil profile.

Keywords: groundwater, nitrate leaching, HYDRUS-2D, soil column

Procedia PDF Downloads 235

Authors: Kavitha A.S., L.Govindaraju

Abstract:

Reinforced earth walls offer excellent solution to many problems associated with earth retaining structures especially under seismic conditions. Use of cohesive soils as backfill material reduces the cost of reinforced soil walls if proper drainage measures are taken. This paper presents a numerical study on the application of a new technique called sandwich technique in reinforced earth walls. In this technique, a thin layer of granular soil is placed above and below the reinforcement layer to initiate interface friction and the remaining portion of the backfill is filled up using the existing insitu cohesive soil. A 6 m high reinforced earth wall has been analysed as a two-dimensional plane strain finite element model. Three types of reinforcing elements such as geotextile, geogrid and metallic strips were used. The horizontal wall displacements and the tensile loads in the reinforcement were used as the criteria to evaluate the results at the end of construction and dynamic excitation phases. Also to verify the effectiveness of sandwich layer on the performance of the wall, the thickness of sand fill surrounding the reinforcement was varied. At the end of construction stage it is found that the wall with sandwich type backfill yielded lower displacements when compared to the wall with cohesive soil as backfill. Also with sandwich backfill, the reinforcement loads reduced substantially when compared to the wall with cohesive soil as backfill. Further, it is found that sandwich technique as backfill and geogrid as reinforcement is a good combination to reduce the deformations of geosynthetic reinforced walls during seismic loading.

Keywords: geogrid, geotextile, reinforced earth, sandwich technique

Procedia PDF Downloads 287

Authors: Erjola Reufi, Thomas Beer

Abstract:

Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of multi directional and closely spaced reinforcement, which can be provided in the form of randomly distributed fibers. Fiber reinforced concrete (FRC) is a composite material consisting of cement, sand, coarse aggregate, water and fibers. In this composite material, short discrete fibers are randomly distributed throughout the concrete mass. The behavioral efficiency of this composite material is far superior to that of plain concrete and many other construction materials of equal cost. The present experimental study considers the effect of steel fibers and polypropylene fiber on the modulus of elasticity of concrete. Hook end steel fibers of length 5 cm and 3 cm at volume fraction of 0.25%, 0.5% and 1.% were used. Also polypropylene fiber of length 12, 6, 3 mm at volume fraction 0.1, 0.25, and 0.4 % were used. Fifteen mixtures has been prepared to evaluate the effect of fiber on modulus of elasticity of concrete. Ultrasonic pulse velocity (UPV) and resonant frequency methods which are two non-destructive testing techniques have been used to measure the elastic properties of fiber reinforced concrete. This study found that ultrasonic wave propagation is the most reliable, easy and cost effective testing technique to use in the determination of the elastic properties of the FRC mix used in this study.

Keywords: fiber reinforced concrete(FRC), polypropylene fiber, resonance, ultrasonic pulse velocity, steel fiber

Procedia PDF Downloads 302

Authors: Nuo Duan, Yi Pik Cheng

Abstract:

This paper presents the data of a series of two-dimensional Discrete Element Method (DEM) simulations of a large-diameter rigid monopile subjected to cyclic loading under a high gravitational force. At present, monopile foundations are widely used to support the tall and heavy wind turbines, which are also subjected to significant from wind and wave actions. A safe design must address issues such as rotations and changes in soil stiffness subject to these loadings conditions. Design guidance on the issue is limited, so are the availability of laboratory and field test data. The interpretation of these results in sand, such as the relation between loading and displacement, relies mainly on empirical correlations to pile properties. Regarding numerical models, most data from Finite Element Method (FEM) can be found. They are not comprehensive, and most of the FEM results are sensitive to input parameters. The micro scale behaviour could change the mechanism of the soil-structure interaction. A DEM model was used in this paper to study the cyclic lateral loads behaviour. A non-dimensional framework is presented and applied to interpret the simulation results. The DEM data compares well with various set of published experimental centrifuge model test data in terms of lateral deflection. The accumulated permanent pile lateral displacements induced by the cyclic lateral loads were found to be dependent on the characteristics of the applied cyclic load, such as the extent of the loading magnitudes and directions.

Keywords: cyclic loading, DEM, numerical modelling, sands

Procedia PDF Downloads 320

Authors: Nader Khalafian, Mohsen Ghaderi

Abstract:

Field observations have revealed many examples of structures which were damaged due to ground surface deformation caused by the faulting phenomena. In this paper some efforts were made in order to estimate the length and location of the ground surface where large displacements were created due to the reverse faulting. This research has conducted in two steps; (1) in the first step, a 2D explicit finite element model were developed using ABAQUS software. A subroutine for Mohr-Coulomb failure criterion with strain softening model was developed by the authors in order to properly model the stress strain behavior of the soil in the fault rapture zone. The results of the numerical analysis were verified with the results of available centrifuge experiments. Reasonable coincidence was found between the numerical and experimental data. (2) In the second step, the effects of the fault dip angle (δ), depth of soil layer (H), dilation and friction angle of sand (ψ and φ) and the amount of fault offset (d) on the soil surface displacement and fault rupture path were investigated. An artificial neural network-based model (ANN), as a powerful prediction tool, was developed to generate a general model for predicting faulting characteristics. A properly sized database was created to train and test network. It was found that the length and location of the zone of displaced ground surface can be accurately estimated using the proposed model.

Keywords: reverse faulting, surface deformation, numerical, neural network

Procedia PDF Downloads 421

Authors: Bal Deep Sharma, Suresh Ray Yadav

Abstract:

Local soils are often chosen due to their widespread availability and low cost. However, these soils typically have poor durability, which can lead to significant limitations in their use for construction. To address this issue, various soil stabilization techniques have been developed and used over the years. This study investigates the viability of employing the mineral polymerization (MIP) technique to stabilize black soils, intending to enhance their suitability for construction applications. This technique involves the microstructural transformation of certain clay minerals into solid and stable compounds exhibiting characteristics similar to hydroxy sodalite, feldspathoid, or zeolite. This transformation occurs through the action of an alkaline reactant at atmospheric pressure and low temperature. The soil sample was characterized using grain size distribution, Atterberg limit test, organic content test, and pH-value tests. The unconfined compressive strength of the soil specimens, prepared with varying percentages of sodium hydroxide as an additive and sand as a filler by weight, was determined at the optimum moisture content. The unconfined compressive strength of the specimens was tested under three different conditions: dry, wet, and cycling. The maximum unconfined compressive strengths were 77.568 kg/cm², 38.85 kg/cm², and 56.3 kg/cm² for the dry, wet, and cycling specimens, respectively, while the unconfined compressive strength of the untreated soil was 7.38 kg/cm². The minimum unconfined compressive strength of the wet and cycling specimens was greater than that of the untreated soil. Based on these findings, it can be concluded that these soils can be effectively used as construction material after treatment with sodium hydroxide.

Keywords: soil stabilization technique, soft soil treatment, sodium hydroxide, unconfined compressive strength

Procedia PDF Downloads 80

Authors: Natia Tabatadze

Abstract:

The research aim is to study the physical - mechanical characteristics of structural materials, in particular, hydraulic concrete in the surface active environment and receiving of high strength concrete, low-deformable, resistant to aggressive environment concrete due application of nano technologies. The obtained concrete with additives will by possible to apply in hydraulic structures. We used cement (compressive strength R28=39,42 mPa), sand (0- 5 mm), gravel (5-10 mm, 10-20 mm), admixture CHRYSO® Fuge B 1,5% dosage of cement. CHRYSO® Fuge B renders mortar and concrete highly resistant to capillary action and reduces, or even eliminates infiltration of water under pressure. The fine particles that CHRYSO® Fuge B contains combine with the lime in the cement to form water repellent particles. These obstruct the capillary action within concrete. CHRYSO® Fuge B does not significantly modify the characteristics of the fresh concrete and mortar, nor the compressive strength. As result of research, the alkali-silica reaction was improved (relative elongation 0,122 % of admixture instead of 0,126 % of basic concrete after 14 days). The aggressive environment impact on the strength of heavy concrete, fabricated on the basis of the hydraulic admixture with the penetrating waterproof additives also was improved (strength on compression R28=47,5 mPa of admixture instead of R28=35,8 mPa), as well as the mass water absorption (W=3,37 % of admixture instead of W=1,41 %), volume water absorption (W=1,41 % of admixture instead of W=0,59 %), water tightness (R14=37,9 mPa instead R14=28,7 mPa) and water-resistance (B=18 instead B=12). The basic parameters of concrete with admixture was improved in comparison with basic concrete.

Keywords: structural materials, hydraulic concrete, low-deformable, water absorption for mass, water absorption for volume

Procedia PDF Downloads 320

Authors: Suk Woo Hong, Chang Sung Seok, Jae Mean Koo

Abstract:

Recently, the welding is widely used in modern industry for joining the structures. However, the waterworks pipes are exposed to the fatigue load by cars, earthquake and etc because of being buried underground. Moreover, the residual stress exists in weld zone by welding process and it is well known that the fatigue life of welded structures is degraded by residual stress. Due to such reasons, the crack can occur in the weld zone of pipeline. In this case, The ground subsidence or sinkhole can occur, if the soil and sand are washed down by fluid leaked from the crack of water pipe. These problems can lead to property damage and endangering lives. For these reasons, the estimation of fatigue characteristics for water pipeline weld zone is needed. Therefore, in this study, for fatigue characteristics estimation of spiral welded waterworks pipe, ASTM standard specimens and Curved Plate specimens were collected from the spiral welded waterworks pipe and the fatigue tests were performed. The S-N curves of each specimen were estimated, and then the fatigue life of weldment Curved Plate specimen was predicted by theoretical and analytical methods. After that, the weldment Curved Plate specimens were collected from the pipe and verification fatigue tests were performed. Finally, it was verified that the predicted S-N curve of weldment Curved Plate specimen was good agreement with fatigue test data.

Keywords: spiral welded pipe, prediction fatigue life, endurance limit modifying factors, residual stress

Procedia PDF Downloads 299

Authors: Sultan Al Shafian, Mozaher Ul Kabir, Khondoker Istiak Ahmad, Masnun Abrar, Mahfuza Khanum, Hossain M. Shahin

Abstract:

For structural evaluation of shallow foundation, the modulus of subgrade reaction is one of the most widely used and accepted parameter for its ease of calculations. To determine this parameter, one of the most common field method is Plate Load test method. In this field test method, the subgrade modulus is considered for a specific location and according to its application, it is assumed that the displacement occurred in one place does not affect other adjacent locations. For this kind of assumptions, the modulus of subgrade reaction sometimes forced the engineers to overdesign the underground structure, which eventually results in increasing the cost of the construction and sometimes failure of the structure. In the present study, the settlement of a shallow foundation has been analyzed using both conventional and numerical analysis. Around 25 plate load tests were conducted on a sand fill site in Bangladesh to determine the Modulus of Subgrade reaction of ground which is later used to design a shallow foundation considering different depth. After the collection of the field data, the field condition was appropriately simulated in a finite element software. Finally results obtained from both the conventional and numerical approach has been compared. A significant difference has been observed in the case of settlement while comparing the results. A proper correlation has also been proposed at the end of this research work between the two methods of in order to provide the most efficient way to calculate the subgrade modulus of the ground for designing the shallow foundation.

Keywords: modulus of subgrade reaction, shallow foundation, finite element analysis, settlement, plate load test

Procedia PDF Downloads 181

Authors: Wen-Juinn Chen, Yi-Phei Chou, Jou-Han Wang

Abstract:

Tainan coast is suffering from beach erosion, wave overtopping, and lowland flooding; though most of the shoreline has been protected by seawalls, they still threatened by sea level rise. For coastal resources developing, coastal land utilization, and to draft an appropriate mitigate strategy. Firstly; we must assess the impact of beach erosion under a different scenario of climate change. Here, we have used the meteorological data since 1898 to 2012 to prove that the Tainan area did suffer the impact of climate change. The result shows the temperature has been raised to about 1.7 degrees since 1989. Also, we analyzed the tidal data near the Tainan coast (Anpin site and Junjunn site), it shows sea level rising with a rate about 4.1~4.8 mm/year, this phenomenon will have serious impacts on Tainan coastal area, especially it will worsen coastal erosion. So we have used Bruun rule to calculate the shoreline retreated rate at every two decade period since 2012. Wave data and bottom sand diameter D50 were used to calculate the closure depth that will be used in Bruun formula and the active length of the profile is computed by the beach slope and Dean's equilibrium concept. After analysis, we found that in 2020, the shoreline will be retreated about 3.0 to 12 meters. The maximum retreat is happening at Chigu coast. In 2060, average shoreline retreated distance is 22m, but at Chigu and Tsenwen, shoreline may be backward retreat about 70m and will be reached about 130m at 2100, this will cause a lot of coastal land loss to the sea, protect and mitigate project must be quickly performed.

Keywords: sea level rise, shoreline, coastal erosion, climate change

Procedia PDF Downloads 407

Authors: M. Ibrahim Ali, M. El Dawi, M. A. Mohamed Ali

Abstract:

In this study, the use of magnetic gradient survey, and the geoelectrical ground methods used together to explore archaeological features in Nuri’s pyramids area. Research methods used and the procedures and methodologies have taken full right during the study. The magnetic survey method was used to search for archaeological features using (Geoscan Fluxgate Gradiometer (FM36)). The study area was divided into a number of squares (networks) exactly equal (20 * 20 meters). These squares were collected at the end of the study to give a major network for each region. Networks also divided to take the sample using nets typically equal to (0.25 * 0.50 meter), in order to give a more specific archaeological features with some small bipolar anomalies that caused by buildings built from fired bricks. This definition is important to monitor many of the archaeological features such as rooms and others. This main network gives us an integrated map displayed for easy presentation, and it also allows for all the operations required using (Geoscan Geoplot software). The parallel traverse is the main way to take readings of the magnetic survey, to get out the high-quality data. The study area is very rich in old buildings that vary from small to very large. According to the proportion of the sand dunes and the loose soil, most of these buildings are not visible from the surface. Because of the proportion of the sandy dry soil, there is no connection between the ground surface and the electrodes. We tried to get electrical readings by adding salty water to the soil, but, unfortunately, we failed to confirm the magnetic readings with electrical readings as previously planned.

Keywords: archaeological features, independent grids, magnetic gradient, Nuri pyramid

Procedia PDF Downloads 482

Authors: Tarek S. Duzan, Fisal Ben Ammer, Mohamed Sula

Abstract:

In some places within Sirt Basin-Libya, it has been noticed that seismic data below pre-upper cretaceous unconformity (PUK) is hopeless to resolve the large-scale structural features and is unable to fully determine reservoir delineation. Seismic artifacts (multiples) are observed in the reservoir zone (Nubian Formation) below PUK, which complicate the process of seismic interpretation. The nature of the unconformity and the structures below are still ambiguous and not fully understood which generates a significant gap in characterizing the geometry of the reservoir, the uncertainty accompanied with lack of reliable seismic data creates difficulties in building a robust geological model. High resolution dipmeter is highly useful in steeply dipping zones. This paper uses FMl and OBMl borehole images (dipmeter) to analyze the structures below the PUK unconformity from two wells drilled recently in the North Gialo field (a mature reservoir). In addition, borehole images introduce new evidences that the PUK unconformity is angular and the bedding planes within the Nubian formation (below PUK) are significantly titled. Structural dips extracted from high resolution borehole images are used to construct a new geological model by the utilization of latest software technology. Therefore, it is important to use the advance well logs technology such as FMI-HD for any future drilling and up-date the existing model in order to minimize the structural uncertainty.

Keywords: FMI (formation micro imager), OBMI (oil base mud imager), UBI (ultra sonic borehole imager), nub sandstone reservoir in North gialo

Procedia PDF Downloads 319

Authors: Samkeliso S. Ndzimandze, Welldone Moyo, Oranso T. Mahlangu, Adolph A. Muleja, Alex T. Kuvarega, Thabo T. I. Nkambule

Abstract:

The high cost of precursor materials has hindered the commercialization of ceramic membrane technology in water treatment. In this work, a ceramic membrane disc (approximately 50 mm in diameter and 4 mm thick) was prepared from low-cost starting materials, kaolin, and fly ash by pressing at 200 bar and calcining at 900 °C. The fabricated membrane was characterized for various physicochemical properties, natural organic matter (NOM) removal as well as fouling propensity using several techniques. Further, the ceramic membrane was tested on samples collected from four drinking water treatment plants in KwaZulu-Natal, South Africa (named plants 1-4). The membrane achieved 48.6%, 54.6%, 57.4%, and 76.4% bulk UV254 reduction for raw water at plants 1, 2, 3, and 4, respectively. These removal rates were comparable to UV254 reduction achieved by coagulation/flocculation steps at the respective plants. Further, the membrane outperformed sand filtration steps in plants 1-4 in removing disinfection by-product precursors (8%-32%) through size exclusion. Fluorescence excitation-emission matrices (FEEM) studies showed the removal of fluorescent NOM fractions present in the water samples by the membrane. The membrane was fabricated using an up-scalable facile method, and it has the potential for application as a polishing step to complement conventional processes in water treatment for drinking purposes.

Keywords: crossflow filtration, drinking water treatment plants, fluorescence excitation-emission matrices, ultraviolet 254 (UV₂₅₄)

Procedia PDF Downloads 43

Authors: Fourar Ali, Fourar Fatima Zohra

Abstract:

Knowledge of sediment characteristics is fundamental to understanding their sedimentary functioning: sedimentation, settlement, and erosion processes of cohesive sediments are controlled by complex interactions between physical, chemical, and biological factors. Sediment transport is of primary importance in river hydraulics and river engineering. Indeed, the displacement of sediments can lead to lasting modifications of the bed in terms of its elevation, slope and roughness. The protection of a bank, for example, is likely to initiate a local incision of the river bed, which, in turn, can lead to the subsidence of the bank. The flows in the natural environment occur in general with heterogeneous boundary conditions because of the distribution of the roughnesses of the fixed or mobile bottoms and of the important deformations of the free surface, especially for the flows with a weak draft considering the irregularity of the bottom. Bedforms significantly influence flow resistance. The arrangement of particles lining the bottom of the stream bed or experimental channel generates waveforms of different sizes that lead to changes in roughness and consequently spatial variability in the turbulent characteristics of the flow. The study which is focused on the laws of friction in alluvial beds, aims to analyze the characteristics of flows and materials constituting the natural channels. Experimental results were obtained by simulating these flows on a rough bottom in an experimental channel at the Hydraulics Laboratory of the University of Batna 2. The system of equations governing the problem is solved using the program named: CLIPPER.5 and ACP.

Keywords: free surface flow, heterogeneous sand, moving bottom bed, friction coefficient, bottom roughness

Procedia PDF Downloads 90

Authors: Trung Le Thanh

Abstract:

Bored piles are always the optimal solution for high-rise building foundations. They have many advantages, such as large diameter, large pile length and construction in all different geological conditions. However, due to construction characteristics, the load-bearing capacity of bored piles is not optimal because wall friction is reduced due to poor contact between the pile and the surrounding soil. Therefore, grouting technology along the pile body helps improve the load-bearing capacity of bored piles significantly through increasing the skin resistance of the pile and surrounding soil. The improvement of pile skin resistance depends on the parameters of grouting technology, especially grouting volume, mortar viscosity, mortar strength,... and different geological conditions. Studies show that the technology of grouting piles on sandy soil is more effective than on clay. This article presents an experimental model to determine the load-bearing capacity of bored piles with a diameter of 400 mm and a length of 3 m on sand with different slurry volume in Tan Uyen city, Binh Duong province. On that basis, analyze the correlation between the increase in load-bearing capacity of bored piles without and with shaft grouting pile. Research results show that the wall resistance of shaft grouted piles increases 2-3 times compared to piles without grouting, and the pile's load-bearing capacity increases significantly. The article's research provides scientific value for consulting work on the design of bored piles when grouted along the pile body.

Keywords: bored pile, shaft grouting, bearing capacity, pile shaft resistance

Procedia PDF Downloads 65

Authors: E. C. Mattos, V. S. M. G. Daros, R. Dal Col, A. L. Nascimento

Abstract:

The aim of this study is to present the results of a retrospective survey on the foreign matter found in foods analyzed at the Adolfo Lutz Institute, from July 2001 to July 2015. All the analyses were conducted according to the official methods described on Association of Official Agricultural Chemists (AOAC) for the micro analytical procedures and Food and Drug Administration (FDA) for the macro analytical procedures. The results showed flours, cereals and derivatives such as baking and pasta products were the types of food where foreign matters were found more frequently followed by condiments and teas. Fragments of stored grains insects, its larvae, nets, excrement, dead mites and rodent excrement were the most foreign matter found in food. Besides, foreign matters that can cause a physical risk to the consumer’s health such as metal, stones, glass, wood were found but rarely. Miscellaneous (shell, sand, dirt and seeds) were also reported. There are a lot of extraneous materials that are considered unavoidable since are something inherent to the product itself, such as insect fragments in grains. In contrast, there are avoidable extraneous materials that are less tolerated because it is preventable with the Good Manufacturing Practice. The conclusion of this work is that although most extraneous materials found in food are considered unavoidable it is necessary to keep the Good Manufacturing Practice throughout the food processing as well as maintaining a constant surveillance of the production process in order to avoid accidents that may lead to occurrence of these extraneous materials in food.

Keywords: extraneous materials, food contamination, foreign matter, surveillance

Procedia PDF Downloads 359

Authors: Tarek Abdoun, Ricardo Dobry

Abstract:

This paper is a systematic effort to clarify why field liquefaction charts based on Seed and Idriss’ Simplified Procedure work so well. This is a necessary step toward integrating the states of the art (SOA) and practice (SOP) for evaluating liquefaction and its effects. The SOA relies mostly on laboratory measurements and correlations with void ratio and relative density of the sand. The SOP is based on field measurements of penetration resistance and shear wave velocity coupled with empirical or semi-empirical correlations. This gap slows down further progress in both SOP and SOA. The paper accomplishes its objective through: a literature review of relevant aspects of the SOA including factors influencing threshold shear strain and pore pressure buildup during cyclic strain-controlled tests; a discussion of factors influencing field penetration resistance and shear wave velocity; and a discussion of the meaning of the curves in the liquefaction charts separating liquefaction from no liquefaction, helped by recent full-scale and centrifuge results. It is concluded that the charts are curves of constant cyclic strain at the lower end (Vs1 < 160 m/s), with this strain being about 0.03 to 0.05% for earthquake magnitude, Mw ≈ 7. It is also concluded, in a more speculative way, that the curves at the upper end probably correspond to a variable increasing cyclic strain and Ko, with this upper end controlled by over consolidated and preshaken sands, and with cyclic strains needed to cause liquefaction being as high as 0.1 to 0.3%. These conclusions are validated by application to case histories corresponding to Mw ≈ 7, mostly in the San Francisco Bay Area of California during the 1989 Loma Prieta earthquake.

Keywords: permeability, lateral spreading, liquefaction, centrifuge modeling, shear wave velocity charts

Procedia PDF Downloads 297

Authors: Ali Fallah Yeznabad, Mohammad H. Baziar, Alireza Saedi Azizkandi

Abstract:

Rafts may be used when a low bearing capacity exists underneath the foundation and may be combined by piles in some special circumstances; such as to reduce settlements or high groundwater to control buoyancy. From structural point of view, these piles could be both connected or disconnected from the raft and are to be classified as Piled Rafts (PR) or Disconnected Piled Rafts (DPR). Although the researches about the behavior of piled rafts subjected to vertical loading is really extensive, in the context of dynamic load and earthquake loading, the studies are very limited. In this study, to clarify these foundations’ performance under dynamic loading, series of Shaking Table tests have been performed. The square raft and four piles in connected and disconnected configurations were used in dry silica sand and the model was experimented using a shaking table under 1-g conditions. Moreover, numerical investigation using finite element software have been conducted to better understand the differences and advantages. Our observations demonstrates that in connected Piled Rafts piles have to bear greater amount of moment in their upper parts, however this moments are approximately 40% lower in disconnected piled rafts in the same conditions and loading. Considering the Rafts’ lateral movement which be of crucial importance in foundations performance evaluation, connected piled rafts show much better performance with about 30% less lateral movement. Further, it was observed on confirmed both through laboratory tests and numerical analysis, that adding the superstructure over the piled raft foundation the raft separates from the soil and it significantly increases rocking of the raft which was observed to be the main reason of increase in piles’ moments under superstructure interaction with the foundation.

Keywords: Piled Rafts (PR), Disconnected Piled Rafts (DPR), dynamic loading, shaking table, seismic performance

Procedia PDF Downloads 430

Authors: Haitham Nabil Zaghlol Hasan

Abstract:

This research aims to study the means of securing graves in the Egyptian kingdom era, and revolves around many basic ideas used by the ancient Egyptian to protect his graves from thieves, which included architectural characteristics, which gave it importance only others. The most important of which was the choice of the place of the grave, which chose a kohl place in the desert to protect the graves, which is the valley of kings, and whether the choice of that place had an impact in protecting the grave or not, in addition to other elements followed in the architectural planning, which was in the valley of kings. The multiplicity of the tomb, the construction of the well chamber to deceive the thieves by the end of the graves suddenly, the construction of the wells of the tombs, which contained the burial chamber at the bottom of the main well and the effect of all these factors on the graves, and this shows the importance of the graves to the ancient Egyptian and his belief in resurrection and immortality. The Egyptian resorted to the elements of protection and was a religious worker by The protector gods and special texts to protect the deceased from any danger to protect the tomb. As for the human factor of securing the tomb through human guards (police) and security teams based on the guard and the words indicating the protection and the guard teams and the teams of the majai. The most important developments that arose on the cemetery from Tamit entrance, corridors, chambers, burial chamber and coffin, and the use of sand to close the well after from one cemetery to another and from time to time where it was built in the late period inside the temple campus to be under the attention of the priests and their protection, as the study dealt with an analytical study For the means of securing graves in the Egyptian kingdom period.

Keywords: Egypt, archaeology, civilization, Egyptian

Procedia PDF Downloads 75

Authors: Camarena Rodriguez C. S., Portocarrero Bonifaz A., Palma Esparza R., Romero Carlos N. A.

Abstract:

Adobe is a construction material that fulfills the same function as a conventional brick. Widely used since ancient times, it is present in an appreciable percentage of buildings in Latin America. Adobe is a mixture of clay and sand. The interest in the study of the properties of this material arises due to its presence in the infrastructure of hospital´s radiological services, located in places with low economic resources, for the attenuation of radiation. Some materials such as lead and concrete are the most used for shielding and are widely studied in the literature. The present study will determine the mass attenuation coefficient of Adobe. The minimum required thicknesses for the primary and secondary barriers will be estimated for the shielding of radiological facilities where conventional and dental X-rays are performed. For the experimental procedure, an X-ray source emitted direct radiation towards different thicknesses of an Adobe barrier, and a detector was placed on the other side. For this purpose, an UNFORS Xi solid state detector was used, which collected information on the difference of radiation intensity. The initial parameters of the exposure started at 45 kV; and then the tube tension was varied in increments of 5 kV, reaching a maximum of 125 kV. The X-Ray tube was positioned at a distance of 0.5 m from the surface of the Adobe bricks, and the collimation of the radiation beam was set for an area of 0.15 m x 0.15 m. Finally, mathematical methods were applied to determine the mass attenuation coefficient for different energy ranges. In conclusion, the mass attenuation coefficient for Adobe was determined and the approximate thicknesses of the most common Adobe barriers in the hospital buildings were calculated for their later application in the radiological protection.

Keywords: Adobe, attenuation coefficient, radiological protection, shielding, x-rays

Procedia PDF Downloads 157

Authors: Moujib Bahri, Ouafa Sakka, Kallel Rahim

Abstract:

This study builds on the literature about the effects of corruption on economic growth at the firm level, which analyzes how the payment of bribes affect organizational performance. Traditionally, the literature distinguishes two points of view regarding the impact of corruption: grease view and sand view. The grease view is based on the idea that corruption can compensate for the negative effect of red tape on firms’ activities such as innovation and exports. Therefore, some firms will be motivated to pay some additional money to officials in order to reduce the delay related to bureaucratic procedures. On the contrary, the second point of view considers that corruption sands the wheels of the economy and distorts resource allocation because it increases agency and transaction costs and reduces the returns on the investment. We have tested the effect of corruption on innovation and export activities on a sample of 537 Tunisian manufacturing small and medium enterprises (SMEs) using structural equation modeling and path analysis. Tunisia has undergone a revolution in 2010 and since then, the country is experiencing a political instability and economic hardships. Our results do not support the greasing hypothesis suggesting that corruption can reduce the negative effect of bureaucratic delays and the hard access of companies to public services related to exports. Instead, our results support the sanding hypothesis according to which corruption hinders SMEs’ exports through its negative influence on innovation. Furthermore, our results show that the interaction between excessive bureaucratic red tape and corruption has a negative effect on exports. However, the interaction between political instability and corruption increases exports.

Keywords: corruption, exports, SMEs, economic conditions

Procedia PDF Downloads 176