23 research outputs found
Field Simulation Technique to Enhance the Mechanical Strength and Elemental Composition of Soft Clay Soil Using Thermal Treatment
No full textThis paper aims to improve the strength of soft clay soil using thermal treatment through a laboratory study that simulates the field application. The laboratory work consisted of preparing a soft clay (Cu = 14 kPa) inside a metal box (92.5 × 92.5 × 92.5) cm3. Boreholes of diameter 43 mm, with different lengths, spacing, and arrangements, were made inside the soil to work as a guide for heating pipes which connected to a controlled heating system. A novel heating system, using gas as a heat source, was developed and manufactured. After the end of the treatment periods, a load was applied until failure on a (20 × 20) cm2 square footing. Various parameter spacings (3, 4, and 5 times the outer diameter of the borehole), depths (1, 1.5, 2, and 2.5 times the width of the model footing), arrangements (square, circular, and triangular), and heating periods (2, 4, 6, 8, and 10 h) were investigated. The results showed the strength and behavior of the soil when subjected to the heated boreholes at different spacings, depths, and heating times, which were determined to be three times the outer diameter of the borehole, two times the width of the square footing, and eight hours, respectively, while the effect of the arrangement of the heated borehole casings was small. Also, a cone penetration probe (CPT) conducted on the heated soil showed that the unconsolidated shear strength (Cu) increased from 14 to 360 kPa and then decreased to 140 kPa (as an average with depth). In contrast, the average angle of internal friction (Ø) increased from 0 to 52 degrees and decreased to 16 degrees (as an average with depth) from the center of the heating model to the furthest point affected by heating. The EDS formula showed that components such as silicon, aluminum, and iron decreased at 300 °C and increased at 400 °C in the treated soils. The calcium content increased at 200 °C and then decreased sharply at 400 °C. The carbon percentage increased at 300 °C and decreased at 400 °C. The elemental proportions showed little change or remained stable at temperatures between 400 °C and 600 °C
BEARING CAPACITY OF SOFT CLAY IMPROVED BY HEATING THROUGH DIFFERENT SPACING CASED BOREHOLES
No full textThis paper presents the effect of heat treatment on ultimate bearing capacity and total settlement of soft clay. The soft clay that was used in this study was prepared by mixing Baghdad’s clay with sufficient water content which gives a shear strength of 7 kPa.Seven model tests were carried out on soft clay inside a cubic steel box of 750 mm side length after heat treatment, two of which were used as a reference without treatment for comparison. A special heating system was designed and manufactured for this purpose by using the gas as a source of heating through boreholes. Four square patterns casing boreholes having 3.5 cm in diameter and 30cm in length with spacing 3d, 4d, 5d, 6d and 7d (were d is the diameter of the borehole) and the time of heating was six hours for each model. A monotonic load was applied on an aluminum square model footing of 150 mm length and 20 mm thick placed on the center of surface area of the soft clay until the settlement exceeds 10% of the width footing. The results showed that the bearing capacity increases and the settlement decreases with spacing increasing until some limiting value (5d) then the bearing capacity decreases and the settlement increases. The 5d spacing is the best one where the bearing capacity increases nine times and the settlement decreases to one tenth compared with that without heating
Lysimeter experiments of landfill liner enhanced with magnesium oxide
No full textLysimeters are frequently employed to replicate environmental conditions in landfill scenarios due to their relatively economical nature and brief study duration. Lysimeters frequently exhibit varying geometrical characteristics that modify the physical and thermodynamic attributes, potentially influencing waste material's decomposition rate and leaching dynamics. Based on the results of the lysimeter tests, lysimeters effectively evaluate and predict the impact of magnesium oxide (Mgo), a material suitable for constructing landfill liners. The findings substantiate that lysimeter investigations can significantly contribute to landfill engineering by identifying optimal strategies for waste containment and selecting appropriate materials for fabricating landfill barriers. Throughout the experimental procedure, the lysimeter was subjected to leachate application. In each hour of the experiment, the quantities of moisture, electric conductivity value (EC), temperature, settlement, pressure reaching the liner, and the total volume and pH of the obtained effluents were measured each week. This research explores and analyzes the role of magnesium oxide (C-M) in reducing permeability and measuring the shear strength properties of the composite material by utilizing a triaxial test. The sensor results demonstrated that MgO-enhanced liners provided superior long-term performance compared to clay. EC sensors showed MgO liners had lower and more stable conductivity. Moisture content sensors indicated that MgO-treated soil maintained better moisture regulation, reducing leachate. LVDT sensors revealed that MgO liners had minimal settlement, while clay experienced greater and prolonged settlement. Temperature sensors confirmed MgO's consistent thermal stability. In contrast, pressure, Total Dissolved Solid (TDS), pH, and flow rate sensors highlighted MgO's better structural integrity, lower dissolved solids, and controlled permeability over time
Experimental and Numerical Study on Seismic Performance of Batter Pile Groups in Loose Sand: No subtitle
No full textPile foundations are critical for maintaining structural integrity under seismic loading, and batter piles, being inclined elements, offer enhanced resistance to combined vertical and lateral forces compared to conventional vertical piles. The objective of this study is to investigate the seismic performance of negative and positive batter pile groups in loose sand. The research employed experimental and numerical approaches: shaking table tests were conducted on 3×3 pile groups embedded in sand with a relative density of 31.2%, subjected to the El Centro and Kobe earthquakes, while finite element modeling was performed to validate the experimental outcomes. The analysis compared the responses of piles with batter angles of -5°, 0°, and +5° in terms of lateral displacement, vertical displacement, and acceleration. Findings revealed that negative battering substantially amplifies pile group displacements, as demonstrated by a 22.085% increase in maximum lateral displacement and a 23.061% rise in vertical displacement for the El Centro motion when the batter angle shifted from 0° to -5°. Conversely, positive battering reduced displacements by up to 4.765%. The novelty of this work lies in experimentally and numerically quantifying the seismic drawbacks of negative battered piles, thereby providing new insights for optimizing pile group design in seismic regions
Determination of the Adequate Thickness of Granular Subbase Beneath Foundations
No full textWhere the native soils have poor structural qualities or are expansive, the soil investigation report may recommend importation of soils better suited to providing a subbase for structures. This requires considering two soil layers in bearing capacity calculations. Calculation of the ultimate bearing capacity of shallow footing on a two layered system of soil depends on the pattern of the failure surface that develops below the footing. For a weak clay layer overlaid by a top dense sand layer, previous studies assumed that the failure surface is a punching shear failure through the upper sand layer and Prandtl's failure mode in the bottom weak clay layer. In this paper, the bearing capacity of subbase layer underneath by a soft clay layer is investigated. The properties of the subbase material are measured in the laboratory. Design charts were obtained which can be used to select the suitable thickness of the subbase layer for a design allowable bearing capacity
Aplikasi Semiotika Roland Barthes terhadap Makna Takwa dalam QS. al-Hajj [22]: 37
No full textAbstractThis article examines how Roland Barthes' semiotics can be used to understand the meaning of piety in QS. Al-Hajj: 37. The author's background involves the application of the definition of piety as it pertains to the role of the physical and spiritual as it has existed in humans. This study aims to ascertain the true meaning of the word "piety" as it appears in QS. Al-Hajj: 37 from a semiotic standpoint. The descriptive analysis used in this article's research was discovered through library research. Before helping one comprehend how Roland Barthes' semiotics can be applied to the meaning of piety in QS. Al-Hajj: 37. Following a description of Roland Barthes' semiotic theory, the author then discusses the meaning of "piety" in the Qur'an. When Roland Barthes' semiotics are applied to parse the meaning of piety in QS, it leads to the conclusion that there are two levels of the signification of Al-Hajj: 37. In summary, the relational interpretation between the signifiers lafaz al-taqwa and al-wiqayah has been known to be central to the denotative and connotative meanings of piety.Keywords: QS. al-Hajj: 37; Roland Barthes; Semiotics; The meaning of piety. AbstrakArtikel ini menganalisa tentang aplikasi semiotika Roland Barthes terhadap makna takwa dalam QS. al-H{ajj: 37. Latar belakang yang diambil penulis adalah implementasi makna takwa yang disebutkan telah melibatkan peran jasmani dan rohani sebagaimana telah bersemayam dalam diri manusia. Penelitian ini bertujuan untuk mengetahui makna hakiki terma takwa pada QS. al-H{ajj: 37 perspektif semiotika Roland Barthes. Metode penelitian dalam artikel ini menggunakan deskriptif analisis yang diperoleh melalui library research. Sebelum mengarah kepada pemahaman perihal aplikasinya semiotika Roland Barthes terhadap makna takwa dalam QS. al-H{ajj: 37, penulis memaparkan dahulu terkait teori semiotika Roland Barthes, dilanjutkan pembahasan terma takwa dalam al-Qur’an. Sehingga menghasilkan bahwa terdapat dua tingkatan signifikasi pada pengaplikasian semiotika Roland Barthes dalam mengurai makna takwa dalam QS. al-H{ajj: 37. Singkatnya, makna denotatif dan konotatif makna takwa telah diketahui terfokus pada interpretasi relasional antara lafaz al-taqwa> sebagai penanda dan al-wiqa>yah sebagai petanda. Kata Kunci: Makna takwa; QS. al-H{ajj: 37; Roland Barthes; Semiotika
Improvement of nuclear power plants within the perspective of applications of lean manufacturing practices
No full textPhotocatalytic dehydrogenation of liquid alcohols by platinized anatase and other catalysts
No full textThe work described in this thesis was undertaken at the University of Nottingham between October 1981 and November 1984, under the supervision of Dr. R. Rudham. Except where indicated by reference, it is the original work of the author and has not been submitted for any other degree.
The photocatalytic dehydrogenation of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by suspensions of platinum and other metals supported on anatase have been investigated by following carbonyl compound formation under a nitrogen atmosphere. Measurements were made over the temperature range 278-303 K using filtered 366 nm U.V. radiation. Reaction on photodeposited catalysts was consistently associated with an activation energy of 20 + 1 kJ mol-1 , although the activity fell in the sequence: PT/TiO2 > Pd/TiO2 > Rh/TiO2 > Au/TiO2 – O for catalysts with a metal content of 0.5 wt%. The activation energy is identical to that for photoreaction on the anatase support in the presence of oxygen and is believed to be associated with the transport of photoelectrons through the anatase to either metal particles or adsorbed oxygen.
Activities and activation energies for carbonyl compound formation from the photocatalytic dehydrogenation of the individual alcohols were effectively identical on the same catalyst, indicating that the photocatalytic dehydrogenation reaction is not governed by the physical or chemical properties of the reactant alcohol.
With platinized anatase prepared by hydrogen reduction there was an appreciable dark reaction, which was absent with catalysts prepared by photodeposition. It is believed that reduction in hydrogen at elevated temperature renders the anatase support non-stoichiometric, a process favoured by spillover of hydrogen atoms from the platinum particles. The low activation energy for photocatalysis on hydrogen reduced catalyst is considered to be associated with the non-stoichiometric nature of the anatase, which presumably provides an energetically favourable mechanism for photoelectron transport to the metal particles and negates the photoelectron traps responsible for an activation energy of 20 ± 1 kJ mol-1 on the non-reduced catalysts.
A radical mechanism for photocatalytic dehydrogenation is proposed. This mechanism predicts a l1m1 ting quantum yield of one half, which is in good agreement with the value obtained from experiments at different light intensities
Photocatalytic dehydrogenation of liquid alcohols by platinized anatase and other catalysts
No full textThe work described in this thesis was undertaken at the University of Nottingham between October 1981 and November 1984, under the supervision of Dr. R. Rudham. Except where indicated by reference, it is the original work of the author and has not been submitted for any other degree.
The photocatalytic dehydrogenation of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by suspensions of platinum and other metals supported on anatase have been investigated by following carbonyl compound formation under a nitrogen atmosphere. Measurements were made over the temperature range 278-303 K using filtered 366 nm U.V. radiation. Reaction on photodeposited catalysts was consistently associated with an activation energy of 20 + 1 kJ mol-1 , although the activity fell in the sequence: PT/TiO2 > Pd/TiO2 > Rh/TiO2 > Au/TiO2 – O for catalysts with a metal content of 0.5 wt%. The activation energy is identical to that for photoreaction on the anatase support in the presence of oxygen and is believed to be associated with the transport of photoelectrons through the anatase to either metal particles or adsorbed oxygen.
Activities and activation energies for carbonyl compound formation from the photocatalytic dehydrogenation of the individual alcohols were effectively identical on the same catalyst, indicating that the photocatalytic dehydrogenation reaction is not governed by the physical or chemical properties of the reactant alcohol.
With platinized anatase prepared by hydrogen reduction there was an appreciable dark reaction, which was absent with catalysts prepared by photodeposition. It is believed that reduction in hydrogen at elevated temperature renders the anatase support non-stoichiometric, a process favoured by spillover of hydrogen atoms from the platinum particles. The low activation energy for photocatalysis on hydrogen reduced catalyst is considered to be associated with the non-stoichiometric nature of the anatase, which presumably provides an energetically favourable mechanism for photoelectron transport to the metal particles and negates the photoelectron traps responsible for an activation energy of 20 ± 1 kJ mol-1 on the non-reduced catalysts.
A radical mechanism for photocatalytic dehydrogenation is proposed. This mechanism predicts a l1m1 ting quantum yield of one half, which is in good agreement with the value obtained from experiments at different light intensities
