Search results for: soft soils

Authors: Mousa Saleh Daoud

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Rickets is a condition that affects the development of bones in children. It causes soft bones, which can become bowed or curved, this bending and curvature is evident in the age of Walking. The most common cause of rickets is dietary deficiency of vitamin D or Lack of exposure to sunlight or both together. The link between vitamin D and rickets has been known for many years and is well understood by doctors and scientists. If a child does not get enough of the vitamin D, the bones cannot form hard outer shells. This is why they become soft and weak. This study was conducted on children who reviewed by our medical clinic between the years 2011-2013. The study included 400 children, aged between one and six years. 11 children had clear clinical manifestations of rickets of varying degrees and all of them due to lack of vitamin D except for one case of rickets resistant to vitamin D. 389 cases ranged between natural and deficiency in vitamin D without clinical manifestations of Rickets.

Keywords: rickts, bone metabolic diseases, vitamin D, child

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Authors: Dellal Seyyid Ali

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This work Contains an experimental study of the behavior of Chlef sand under effect of various parameters influencing on shear strength. Because of their distinct nature, sands, silts and clays exhibit completely different behavior (shear strength, the Contracting and dilatancy, the angle of internal friction and cohesion ...). By cons when these materials are mixed, their behavior will become different from each considered alone. The behavior of these mixtures (silty sands ...) is currently the state of several studies to better use. We have studied in this work: The influence of the following factors on the shear strength: The density (loose and dense), the fines content (silt), the water content. The apparatus used for the tests is the casagrande shear box. This device, although one may have some disadvantages and modern instrumentation is appropriate used to study the shear strength of soils.

Keywords: shear strength, sand, silt, contractanct, dilatancy, friction angle, cohesion, fines content

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Authors: M. Ekiert, T. Uhl, A. Mlyniec

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Tendons are the biological soft tissue structures composed of collagen, proteoglycan, glycoproteins, water and cells of extracellular matrix (ECM). Tendons, which primary function is to transfer force generated by the muscles to the bones causing joints movement, are exposed to many micro and macro damages. In fact, tendons and ligaments trauma are one of the most numerous injuries of human musculoskeletal system, causing for many people (particularly for athletes and physically active people), recurring disorders, chronic pain or even inability of movement. The number of tendons reconstruction and transplantation procedures is increasing every year. Therefore, studies on soft tissues storage conditions (influencing i.e. tissue aging) seem to be an extremely important issue. In this study, an atomic-scale investigation on the kinetics of decomposition of two selected tendon components – collagen type I (which forms a 60-85% of a tendon dry mass) and elastin protein (which combine with ECM creates elastic fibers of connective tissues) is presented. A molecular model of collagen and elastin was developed based on crystal structure of triple-helical collagen-like 1QSU peptide and P15502 human elastin protein, respectively. Each model employed 4 linear strands collagen/elastin strands per unit cell, distributed in 2x2 matrix arrangement, placed in simulation box filled with water molecules. A decomposition phenomena was simulated with molecular dynamics (MD) method using ReaxFF force field and periodic boundary conditions. A set of NVT-MD runs was performed for 1000K temperature range in order to obtained temperature-depended rate of production of decomposition by-products. Based on calculated reaction rates activation energies and pre-exponential factors, required to formulate Arrhenius equations describing kinetics of decomposition of tested soft tissue components, were calculated. Moreover, by adjusting a model developed for collagen, system scalability and correct implementation of the periodic boundary conditions were evaluated. An obtained results provide a deeper insight into decomposition of selected tendon components. A developed methodology may also be easily transferred to other connective tissue elements and therefore might be used for further studies on soft tissues aging.

Keywords: decomposition, molecular dynamics, soft tissue, tendons

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Authors: Ian Marc G. Cabugsa, Zarine M. Hermita

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Phytoextraction capability of T. catappa in contaminated soils was done in the improvised greenhouse. The plant samples were planted to the soil which contained different concentrations of copper. Chelating agent EDTA was added to observe the uptake and translocation of copper in the plant samples. Results showed a significant increase of copper accumulation with the addition of EDTA at 250 and 1250 mgˑkg-1 concentration of copper in the contaminated soils (p<0.05). While translocation of copper was observed in all treatments, translocation of copper is not significantly enhanced by the addition of EDTA (p>0.05). Uptake and translocation were not directly affected the presence of EDTA. Furthermore, this study suggests that the T. catappa is not a hyperaccumulator of copper, and there is no relationship observed between the length of the plant and the copper uptake in all treatments.

Keywords: chelating agent EDTA, hyperaccumulator, phytoextraction, phytoremediation, terminalia catappa

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Authors: R. Rajeswari

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An investigation was carried out to know the SOC stock and its change over time in benchmark soils of different agroclimatic zones of Tamil Nadu. Roth.C model was used to assess SOC stock under existing and alternate cropping pattern. Soil map prepared on 1:50,000 scale from Natural Resources Information System (NRIS) employed under satellite data (IRS-1C/1D-PAN sharpened LISS-III image) was used to estimate SOC stock in different agroclimatic zones of Tamil Nadu. Fifteen benchmark soils were selected in different agroclimatic zones of Tamil Nadu based on their land use and the areal extent to assess SOC level and its change overtime. This revealed that, between eleven years of period (1997 - 2007). SOC buildup was higher in soils under horticulture system, followed by soils under rice cultivation. Among different agroclimatic zones of Tamil Nadu hilly zone have the highest SOC stock, followed by north eastern, southern, western, cauvery delta, north western, and high rainfall zone. Although organic carbon content in the soils of North eastern, southern, western, North western, Cauvery delta were less than high rainfall zone, the SOC stock was high. SOC density was higher in high rainfall and hilly zone than other agroclimatic zones of Tamil Nadu. Among low rainfall regions of Tamil Nadu cauvery delta zone recorded higher SOC density. Roth.C model was used to assess SOC stock under existing and alternate cropping pattern in viz., Periyanaickenpalayam series (western zone), Peelamedu series (southern zone), Vallam series (north eastern zone), Vannappatti series (north western zone) and Padugai series (cauvery delta zone). Padugai series recorded higher TOC, BIO, and HUM, followed by Periyanaickenpalayam series, Peelamedu series, Vallam series, and Vannappatti series. Vannappatti and Padugai series develop high TOC, BIO, and HUM under existing cropping pattern. Periyanaickenpalayam, Peelamedu, and Vallam series develop high TOC, BIO, and HUM under alternate cropping pattern. Among five selected soil series, Periyanaickenpalayam, Peelamedu, and Padugai series recorded 0.75 per cent TOC during 2025 and 2018, 2100 and 2035, 2013 and 2014 under existing and alternate cropping pattern, respectively.

Keywords: agro climatic zones, benchmark soil, land use, soil organic carbon

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Authors: Aydın Kavak, Özkan Coruk, Adnan Aydıner

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Long-term performance of pavement structures is significantly impacted by the stability of the underlying soils. In situ subgrades often do not provide enough support required to achieve acceptable performance under traffic loading and environmental demands. NovoCrete® is a powder binder-mineral for cement stabilized road pavements soils. NovoCrete® combined with Portland cement at optimum water content increases the crystallize formations during the hydration process, resulting in higher strengths, neutralizes pH levels, and provides water impermeability. These changes in soil properties may lead to transforming existing unsuitable in-situ materials into suitable fill materials. The main features of NovoCrete® are: They are applicable to all types of soil, reduce premature cracking and improve soil properties, creating base and subbase course layers with high bearing capacity by reducing hazardous materials. It can be used also for stabilization of recyclable aggregates and old asphalt pavement aggregate, etc. There are many applications in Germany, Turkey, India etc. In this paper, a few field application in Turkey will be discussed. In the road construction works, this binder material is used for cement stabilization works. In the applications 120-180 kg cement is used for 1 m3 of soil with a 2 % of binder NovoCrete® material for the stabilization. The results of a plate loading test in a road construction site show 1 mm deformation which is very small under 7 kg/cm2 loading. The modulus of subgrade reaction increase from 611 MN/m3 to 3673 MN/m3.The soaked CBR values for stabilized soils increase from 10-20 % to 150-200 %. According to these data weak subgrade soil can be used as a base or sub base after the modification. The potential reduction in the need for quarried materials will help conserve natural resources. The use of on-site or nearby materials in fills, will significantly reduce transportation costs and provide both economic and environmental benefits.

Keywords: soil, stabilization, cement, binder, Novocrete, additive

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Authors: Sara Soltanpour, Adolfo Foriero

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Frost heave is arguably the most problematic adverse phenomenon in cold region areas. Frost heave is a complex process that depends on heat and water transfer. These coupled physical fields generate considerable heave stresses as well as deformations. In the present study, a coupled thermal-hydraulic-mechanical (THM) model using COMSOL Multiphysics in frozen unsaturated soils, such as fine sand, is investigated. Particular attention to the frost heave and temperature distribution, as well as the water migrating during soil freezing, is assessed. The results obtained from the numerical simulations are consistent with the results measured in the full-scale tests conducted by Cold Regions Research and Engineering Laboratory (CRREL).

Keywords: frost heave, numerical simulations, COMSOL software, unsaturated freezing soil

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Authors: I. T. Asowata, A. S. Akinwumiju

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The enrichment of potentially harmful elements (PHEs) in stream sediments (SS) and floodplain soils (FS) poses great environmental hazards to water bodies and other parts of the ecosystem. The aim of this research was to assess the distribution pattern of selected PHEs (Cu, Pb, Zn, Co, Mn, As, Cd, V, Cr, Ni, Th, Sr, and La) in SS of selected rivers that drain Ile-Ife area and their adjacent FS, to ascertain the pollution status of these elements in the study area. 60 samples (40 SS and 20 FS) were purposely collected for this study; the samples were air-dried at room temperature, disaggregated, sieved with > 63 µm and digested with modified aqua reqia (1:1:1 HCl:HNO₃:H₂O) and were analysed with ultra-trace inductively coupled plasma mass spectrometry method (ICP-ES). The geochemical results showed decreasing trend of average contents of PHEs studied Mn > Zn > V > Cr > Pb > La > Sr > Cu > Ni > Co > Th > As > Cd for both SS and FS. Floodplain topsoil in ppm, Cu range from 10.0-180.0; mean, 71.1, Pb, 17.1-255.0; 93.5 and Zn, 83.0-3122.2; 826.0. Also, floodplain sub-soils, Cu range from 30.0-203.1; mean of 76.6, Pb, 16.0-214.0; 77.9 and Zn, 59.1-2351.0; 622.3. Similarly, SS results for Cu, 22.1-257.0; 70.3, Pb, 15.0-172.0; 67.3 and Zn, 65.0-1285.0; 357.8, among other PHEs, suggesting significant level of PHEs enrichment in the studied geo media. Elemental association showed positive and/or negative correlation among the PHEs and also showed different sources of metal enrichment to be largely anthropogenic with some geogenic. Geoaccumulation and metal ratio indexes indicated that FS and SS studied have received significant PHEs of between moderately to strongly polluted, which implies significant environmental implications in the study area.

Keywords: aqua regia, enrichment, GIS, Ile-Ife, potentially harmful elements

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Authors: Buket Canbaz Öztürk, N. Füsun Çam, Günseli Yaprak, Osman Candan

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The external terrestrial radiation exposure is related to the types of rock from which the soils originate. Higher radiation levels are associated with igneous rocks, such as granite, and lower levels with sedimentary rocks. Therefore, this study aims to assess the gamma radiation exposure of soils associated with granitic rocks in Kapıdağ Peninsula, Turkey. In the ongoing study, a comprehensive survey carried out systematically as a part of the environmental monitoring program on radiologic impact of the granitoid areas in Western Anatolia. The activity measurements of the gamma emitters (238U, 232Th and 40K) in the surface soil samples and the granitic rocks carried out by means of NaI(Tl) gamma-ray spectrometry system. To evaluate the radiological hazard of the natural radioactivity, the absorbed dose rate (D), the annual effective dose rate (AED), the radium equivalent activity (Raeq) and the external (Hex) hazard index were calculated according to the UNSCEAR 2000 report. The corresponding absorbed dose rates in air from all natural radionuclides were always much lower than 200 nGy h-1 and did not exceed the typical range of worldwide average values noticed in the UNSCEAR (2000) report. Furthermore, the correlation between soil and granitic rock samples were utilized, and external gamma radiation exposure distribution was mapped in Kapıdağ Peninsula.

Keywords: external absorbed dose, granitic rocks, Kapıdağ Peninsula, soil

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Authors: Latif Adnane, Benaatou Wafa, Pla Vicent

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Handover is of great significance to achieve seamless connectivity in wireless networks. This paper gives an impression of the main factors which are being affected by the soft and the hard handovers techniques. To know and understand the handover process in The Universal Mobile Telecommunications System (UMTS) network, different statistics are calculated. This paper focuses on the quality of service (QoS) of soft and hard handover in UMTS network, which includes the analysis of received power, signal to noise radio, throughput, delay traffic, traffic received, delay, total transmit load, end to end delay and upload response time using OPNET simulator.

Keywords: handover, UMTS, mobility, simulation, OPNET modeler

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Authors: Rene Jimenez, Sonia E. Ruiz, Miguel A. Orellana

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On 09/19/2017, a Mw = 7.1 intraslab earthquake occurred in Mexico causing the collapse of about 40 buildings. Many of these were 5- or 6-story buildings with soft first story; so, it is desirable to perform a structural fragility analysis of typical structures representative of those buildings and to propose a reliable structural solution. Here, a typical 5-story building constituted by regular R/C moment-resisting frames in the first story and confined masonry walls in the upper levels, similar to the collapsed structures on the 09/19/2017 Mexico earthquake, is analyzed. Three different structural solutions of the 5-story building are considered: S1) it is designed in accordance with the Mexico City Building Code-2004; S2) then, the column dimensions of the first story corresponding to S1 are reduced, and S3) viscous dampers are added at the first story of solution S2. A number of dynamic incremental analyses are performed for each structural solution, using a 3D structural model. The hysteretic behavior model of the masonry was calibrated with experiments performed at the Laboratory of Structures at UNAM. Ten seismic ground motions are used to excite the structures; they correspond to ground motions recorded in intermediate soil of Mexico City with a dominant period around 1s, where the structures are located. The fragility curves of the buildings are obtained for different values of the maximum inter-story drift demands. Results show that solutions S1 and S3 give place to similar probabilities of exceedance of a given value of inter-story drift for the same seismic intensity, and that solution S2 presents a higher probability of exceedance for the same seismic intensity and inter-story drift demand. Therefore, it is concluded that solution S3 (which corresponds to the building with soft first story and energy dissipation devices) can be a reliable solution from the structural point of view.

Keywords: demand hazard analysis, fragility curves, incremental dynamic analyzes, soft-first story, structural capacity

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Authors: Munisath Khandoker, Stephan Haefele, Andy Gregory

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Extracellular enzymes play a key role in soil organic carbon (SOC) decomposition and nutrient cycling and are known indicators for soil health; however, it is not understood how these enzymes respond to different land uses and their relationships to other soil properties have not been extensively reviewed. The relationships among the activities of three soil enzymes: β-glucosaminidase (NAG), phosphomonoesterase (PHO) and β-glucosidase (GLU), were examined. The impact of soil organic amendments, soil types and land management on soil enzyme activities were reviewed, and it was hypothesized that soils with increased SOC have increased enzyme activity. Long-term experiments at Rothamsted Research Woburn and Harpenden sites in the UK were used to evaluate how different management practices affect enzyme activity involved in carbon (C) and nitrogen (N) cycling in the soil. Samples were collected from soils with different organic treatments such as straw, farmyard manure (FYM), compost additions, cover crops and permanent grass cover to assess whether SOC can be linked with increased levels of enzymatic activity and what influence, if any, enzymatic activity has on total C and N in the soil. Investigating the interactions of important enzymes with soil characteristics and SOC can help to better understand the health of soils. Studies on long-term experiments with known histories and large datasets can better help with this. SOC tends to decrease during land use changes from natural ecosystems to agricultural systems; therefore, it is imperative that agricultural lands find ways to increase and/or maintain SOC in the soil.

Keywords: biological soil health indicators, extracellular enzymes, soil health, soil, microbiology

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Authors: Chongyang Ye, Rong Liu

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Elastic compression stockings (ECSs) have been widely applied in prophylaxis and treatment of chronic venous insufficiency of lower extremities. The medical function of ECS is to improve venous return and increase muscular pumping action to facilitate blood circulation, which is largely determined by the complex interaction between the ECS and lower limb tissues. Understanding the mechanical transmission of ECS along the skin surface, deeper tissues, and vascular system is essential to assess the effectiveness of the ECSs. In this study, a three-dimensional (3D) finite element (FE) model of the leg-ECS system integrated with a 3D fluid-solid interaction (FSI) model of the leg-vein system was constructed to analyze the biomechanical properties of veins and soft tissues under different ECS compression. The Magnetic Resonance Imaging (MRI) of the human leg was divided into three regions, including soft tissues, bones (tibia and fibula) and veins (peroneal vein, great saphenous vein, and small saphenous vein). The ECSs with pressure ranges from 15 to 26 mmHg (Classes I and II) were adopted in the developed FE-FSI model. The soft tissue was assumed as a Neo-Hookean hyperelastic model with the fixed bones, and the ECSs were regarded as an orthotropic elastic shell. The interfacial pressure and stress transmission were simulated by the FE model, and venous hemodynamics properties were simulated by the FSI model. The experimental validation indicated that the simulated interfacial pressure distributions were in accordance with the pressure measurement results. The developed model can be used to predict interfacial pressure, stress transmission, and venous hemodynamics exerted by ECSs and optimize the structure and materials properties of ECSs design, thus improving the efficiency of compression therapy.

Keywords: elastic compression stockings, fluid-solid interaction, tissue and vein properties, prediction

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Authors: Vinicius Buccelli Ribeiro, Maria Teresa Destro, Mariza Landgraf

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Bacteriophages are one of the most abundant replicating entities on Earth and can be found everywhere in which their hosts live and there are reports regarding isolation from different niches such as soil and foods. Since studies are moving forward with regard to biotechnology area, different research projects are being performed focusing on the phage technology and its use by the food industry. This study aimed to evaluate a cocktail (LP501) of phages isolated in Brazil for its lytic potential against Listeria monocytogenes. Three bacteriophages (LP05, LP12 and LP20) were isolated from soil samples and all of them showed 100% lysis against a panel of 10 L. monocytogenes strains representing different serotypes of this pathogen. A mix of L. monocytogenes 1/2a and 4b were inoculated in soft cheeses (approximately 105 cfu/cm2) with the phage cocktail added thereafter (1 x 109 PFU/cm2). Samples were analyzed immediately and then stored at 10°C for ten days. At 30 min post-infection, the cocktail reduced L. monocytogenes counts approximately 1.5 logs, compared to controls without bacteriophage. The treatment produced a statistically significant decrease in the counts of viable cells (p < 0.05) and in all assays performed we observed a decrease of up to 4 logs of L. monocytogenes. This study will make available to the international community behavioral and molecular data regarding bacteriophages present in soil samples in Brazil. Furthermore, there is the possibility to apply this new cocktail of phages in different food products to combat L. monocytogenes.

Keywords: bacteriophages, biocontrol, listeria monocytogenes, soft cheese

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Authors: Mahinaz Saad

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Little empirical data exists regarding smartphone usage for news consumption in the UAE, and no previous research explored undergraduate female university students’ usage of smartphones. This represents a gap in the professional literature and makes it an important area to examine. Uses and Gratifications theory is used to study the motivations of consumers for adopting a particular type of communication tool. This theory is an audience-centred approach to understanding mass communication that assumes audiences are active consumers of media and explains why and how people seek out specific media to satisfy needs. This theory is particularly relevant given the rapid development of new communication technologies. Situated within this theoretical framework, this study utilised a quantitative research design to explore respondents’ (N=488) how and why respondents use their smartphones. Further, this study explored the relationship between mobile news use and the use of other mediums for news access and how different gratifications predict mobile hard news use and mobile soft news use. Results revealed that smartphones often replace traditional media as a news source and have become students’ primary source of news. Results also revealed that different gratifications can be used as a predictor of mobile hard news and soft news and that most students use their smartphones to access soft news. These results are fundamental in allowing us to predict possible future trends relating to news consumption in the UAE and the myriad ways in which the media landscape is changing.

Keywords: uses and gratifications, smartphones, university students, news consumption

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Authors: Aaron Aboshio

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Numerical study of the static response of homogeneous clay stratum considering a wide range of cohesion and subject to foundation loads is presented. The linear elastic–perfectly plastic constitutive relation with the von Mises yield criterion were utilised to develop a numerically cost effective finite element model for the soil while imposing a rigid body constrain to the foundation footing. From the analyses carried out, estimate of the bearing capacity factor, Nc as well as the ultimate load-carrying capacities of these soils, effect of cohesion on foundation settlements, stress fields and failure propagation were obtained. These are consistent with other findings in the literature and hence can be a useful guide in design of safe foundations in clay soils for buildings and other structure.

Keywords: bearing capacity factors, finite element method, safe bearing pressure, structure-soil interaction

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Authors: Houssam A. Toutanji, Meng Han

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This study focuses on the development of a fracture mechanics based-model that predicts the debonding behavior of FRP strengthened RC beams. In this study, a database includes 351 concrete prisms bonded with FRP plates tested in single and double shear were prepared. The existing fracture-mechanics-based models are applied to this database. Unfortunately the properties of adhesive layer, especially a soft adhesive layer, used on the specimens in the existing studies were not always able to found. Thus, the new model’s proposal was based on fifteen newly conducted pullout tests and twenty four data selected from two independent existing studies with the application of a soft adhesive layers and the availability of adhesive properties.

Keywords: carbon fiber composite materials, interface response, fracture characteristics, maximum shear stress, ultimate transferable load

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Authors: Muhammad Mohsin, Mir Md Abdus Salam, Pertti Pulkkinen, Ari Pappinen

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Soil polluted with elevated level of nickel (Ni) concentration may cause severe hazards to humans and forest ecosystems, for example, by polluting underground water reserves, affecting food quality and by reducing agricultural productivity. The present study investigated the phytoextraction ability of Salix schwerinii, enhanced with an application of the N100 (11-amino-1-hydroxyundecylidene) chelate. N100 has proved to be a non-toxic, low risk of leaching, environmentally friendly and easily biodegradable chelate that has a potential for metal chelation. The Salix were grown in garden soil that was also amended with nickel (Ni; 150 mg kg⁻¹). Multiple doses of N100 were applied to the treatments as follows: Ni + N100 1.2 g and Ni+ N100 2.4 g. Furthermore, N100 doses were also repeated with the control soil. The effect of N100 on height growth, biomass, and the accumulation of Ni in Salix in polluted soils was studied. In this study, N100 application was found to be effective in enhancing height and biomass growth under polluted treatments. Total reflection X-ray fluorescence (TXRF) spectrometry was used to determine the concentration of Ni in the Salix tissues. The total Ni concentrations in the soils amended with N100 increased substantially by up to 324% as compared to the control. The Ni translocation factor (TF) and bioconcentration factor (BF) values for S. schwerinii increased with the application of N100 as varied from 0.45–1.25 and 0.80‒1.50, respectively. This study revealed that S. schwerinii is suitable for the phytoextraction of Ni-contaminated soils.

Keywords: bisphosphonic acid, nickel, phytoextraction, Salix

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Authors: Ratmawati Malaka, Effendi Abustam, Kusumandari Indah Prahesti, Sudirman Baco

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Dangke is natural cheese from Enrekang South Sulawesi, Indonesia produced through aglutination buffalo milk, cow, goat or sheep using the sap of papaya (Carica papaya). Dangke has been widely known in South Sulawesi but this soft cheese product diversification by using passion fruit juice as milk clotting agents has not been used. Passion fruit juice has a high acidity with a pH of around 4 - 4.5 and has a proteolytic enzyme, so that it can be used to agglutinate milk. The purpose of this study was to investigate the nature Dangke using passion fruit juice as coagulate milk. Dangke made by 10 lt of raw milk by heating at a temperature of 73oC with coagulant passion fruit juice (7.5% and 10%), and added 1% salt. Curd clot and then be formed using a coconut shell, is then pressed until the cheese is compact. The cheese is then observed for 28 days ripening at a temperature of about 5 ° C. Dangke then studied to violence, pH, fat levels and microstructure. Hardness is determined using CD-shear Force, pH is measured using a pH meter Hanna, and fat concentrations were analyzed with methods of proximate. Microstructure viewed using a light microscope with magnification 1000 x. The results showed that the levels of clotting material very significant influence on hardness, pH, and lipid levels. Maturation increase the hardness but lower the pH, the level of fat soft cheese with an average Dangke respectively 21.4% and 30.5% on 7.5% addition of passion fruit juice and 10%. Dangke violence is increasing with the increasing maturation time (1.38 to 3.73 kg / cm), but Dangke pH was decreased by the increase in storage maturation (5.34 to 4.1). Microktrukture cheeses coagulated with 10% of the passion fruit are very firmer and compact with a full globular fat of 7.5%. But the sensory properties of the soft cheese similar in both treatment. The manufacturing process with the addition of coagulant passion fruit juice on making Dangke affect hardness, pH, fat content and microstructure during storage at 5 ° C for 1 d - 28 d.

Keywords: dangke, passion fruits, microstructure, cheese

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Authors: Ahmad Idris, O.A. Uche, Ado Y Abdulfatah

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Lateritic soils are found in abundance and are the most common types of soils used in construction of roads and embankments in Nigeria. Strength properties of the soils depend on the amount of compaction applied and the amount of water available in the soil at the time of compaction. In this study, the influence of the compactive effort and that of the amount of water in the soil in the determination of the shear strength properties of lateritic soil was investigated. Lateritic soil sample was collected from an existing borrow pit in Kano, Nigeria and its basic characteristics were determined and the soil was classified according to AASHTO classification method. The soil was then compacted under various compactive efforts and at wide range of moisture contents. The maximum dry density (MDD) and optimum moisture content (OMC) at each compactive effort was determined. Unconfined undrained triaxial test was carried out to determine the shear strength properties of the soil under various conditions of moisture and energy. Preliminary results obtained indicated that the soil is an A-7-5 soil. The final results obtained shows that as the compaction energy is increased, both the cohesion and friction angle increased irrespective of the moisture content used in the compaction. However, when the amount of water in the soil was increased and compaction effort kept constant, only the cohesion of the soil increases while the friction angle shows no any pattern of variation. It was also found that the highest values for cohesion and friction angle were obtained when the soil was compacted at the highest energy and at OMC.

Keywords: laterite, OMC, compaction energy, moisture content

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Authors: Sabir Tehrankhan Hasanov, Mir Movsum Anar Dadashev

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The article provides a brief overview of irrigation systems and canals applied to slopes, landslide-prone, seismic areas, and swelling and collapsing soils. The contemporary construction of the canal used for irrigation, energy, and water supply purposes is described. In order to ensure the durability, longevity, and reliability of the channel, a damping mat made of cast material is created under its cover, and the top is covered with a waterproof screen. Dowels are placed on the bottom and sides of the channel, and the bottom dowel is riveted to the solid bedrock and connected with piles placed at certain distances. Drainage was placed next to the bottom dowel, an operation road was created on one side of the channel, and a berm road was created on the other side. A bathtub was built on the side of the road, and a forest-bush strip was built on its bank.

Keywords: slope, channel, landslide, collapse, swell, soil, structure

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Authors: Nicolaas Unland, John Webb

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The acidification and mobilisation of metals during the oxidation of acid sulfate soils exposed during lake bed drying is an increasingly common phenomenon under climate scenarios with reduced rainfall. In order to assess the risk of generating high concentrations of acidity and dissolved metals, chromium suite analysis are fundamental, but sometimes limited in characterising the potential risks they pose. This study combines such fundamental test work, along with incubation tests and 1D modelling to investigate the risks associated with the drying of Third Reedy Lake in South East Australia. Core samples were collected from a variable depth of 0.5 m below the lake bed, at 19 locations across the lake’s footprint, using a boat platform. Samples were subjected to a chromium suite of analysis, including titratable actual acidity, chromium reducible sulfur and acid neutralising capacity. Concentrations of reduced sulfur up to 0.08 %S and net acidities up to 0.15 %S indicate that acid sulfate soils have formed on the lake bed during permanent inundation over the last century. A further sub-set of samples were prepared in 7 columns and subject to accelerated heating, drying and wetting over a period of 64 days in laboratory. Results from the incubation trial indicate that while pyrite oxidation proceeded, minimal change to soil pH or the acidity of leachate occurred, suggesting that the internal buffering capacity of lake bed sediments was sufficient to neutralise a large proportion of the acidity produced. A 1D mass balance model was developed to assess potential changes in lake water quality during drying based on the results of chromium suite and incubation tests. Results from the above test work and modelling suggest that acid sulfate soils pose a moderate to low risk to the Third Reedy Lake system. Further, the risks can be effectively managed during the initial stages of lake drying via flushing with available mildly alkaline water. The study finds that while test work such as chromium suite analysis are fundamental in characterizing acid sulfate soil environments, they can the overestimate risks associated with the soils. Subsequent incubation test work may more accurately characterise such soils and lead to better-informed management strategies.

Keywords: acid sulfate soil, incubation, management, model, risk

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Authors: Inci Develioglu, Hasan Firat Pulat

Abstract:

Sustainable development is one of the most important topics in today's world, and it is also an important research topic for geoenvironmental engineering. Dredging process is performed to expand the river and port channel, flood control and accessing harbors. Every year large amount of sediment are dredged for these purposes. Dredged marine soils can be reused as filling materials, road and foundation embankments, construction materials and wildlife habitat developments. In this study, geotechnical engineering properties and compressibility behavior of dredged soil obtained from the Izmir Bay were investigated. The samples with four different organic matter contents were obtained and particle size distributions, consistency limits, pH and specific gravity tests were performed. The consolidation tests were conducted to examine organic matter content (OMC) effects on compressibility behavior of dredged soil. This study has shown that the OMC has an important effect on the engineering properties of dredged soils. The liquid and plastic limits increased with increasing OMC. The lowest specific gravity belonged to sample which has the maximum OMC. The specific gravity values ranged between 2.76 and 2.52. The maximum void ratio difference belongs to sample with the highest OMC (De_11% = 0.38)_. As the organic matter content of the samples increases, the change in the void ratio has also increased. The compression index increases with increasing OMC.

Keywords: compressibility, consolidation, geotechnical properties, organic matter content, dredged soil

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Authors: Mohamed Emran, Giovanni Pardini, Maria Gispert, Mohamed Rashad

Abstract:

Land use and abandonment in semi-arid degraded ecosystems may cause regressive dynamics in vegetation cover affecting organic matter contents, soil nutrients and structural stability, thus reducing soil resistance to erosion. Mediterranean areas are generally subjected to climatic fluctuations, which modify soil conditions and hydrological processes, such as runoff and water infiltration within the upper soil horizons. Low erosion rates occur in very fragile and shallow soils with minor clay content progressively decrease organic carbon C and nitrogen N pools in the upper soil horizons. Seven soils were selected representing variant context of land use and abandonment at the Cap de Creus Peninsula, Catalonia, NE Spain, from recent cultivated vines and olive groves, mid abandoned forests standing under cork and pine trees, pasture to late abandoned Cistus and Erica scrubs. The aim of this work was to study the effect of changes in land use and abandonment on the depletion of soil organic carbon and nitrogen transported by runoff water in shallow soils after natural rainfall events during two years with different rainfall patterns (1st year with low rainfall and 2nd year with high rainfall) by i) monitoring the most significant soil erosion parameters at recorded rainfall events, ii) studying the most relevant soil physical and chemical characteristics on seasonal basis and iii) analysing the seasonal trends of depleted carbon and nitrogen and their interaction with soil surface compaction parameters. Significant seasonal variability was observed in the relevant soil physical and chemical parameters and soil erosion parameters in all soils to establish their evolution under land use and abandonment during two years of different rainfall patterns (214 and 487 mm per year), giving important indications on soil response to rainfall impacts. Erosion rates decreased significantly with the increasing of soil C and N under low and high rainfall. In cultivated soils, C and N depletion increased by 144% and 115%, respectively by 13% increase in erosion rates during the 1st year with respect to the 2nd year. Depleted C and N were proportionally higher in soils under vines and olive with vulnerable soil structure and low soil resilience leading to degradation, altering nutrients cycles and causing adverse impact on environmental quality. Statistical analysis underlined that, during the 1st year, soil surface was less effective in preserving stocks of organic resources leading to higher susceptibility to erosion with consequent C and N depletion. During the 2nd year, higher organic reserve and water storage occurred despite the increasing of C and N loss with an effective contribution from soil surface compaction parameters. The overall estimation during the two years indicated clear differences among soils under vines, olive, cork and pines, suggesting on the one hand, that current cultivation practices are inappropriate and that reforestation with pines may delay the achievement of better soil conditions. On the other hand, the natural succession of vegetation under Cistus, pasture and Erica suggests the recovery of good soil conditions.

Keywords: land abandonment, land use, nutrient's depletion, soil erosion

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Authors: M. López-Moreno, L. Lugo Avilés, F. Román, J. Lugo Rosas, J. Hernández-Viezcas Jr., Peralta-Videa, J. Gardea-Torresdey

Abstract:

Degradation of agricultural soils has increased rapidly during the last 20 years due to the indiscriminate use of pesticides and other anthropogenic activities. Currently, there is an urgent need of soil restoration to increase agricultural production. Utilization of sewage sludge or municipal solid waste is an important way to recycle nutrient elements and improve soil quality. With these amendments, nutrient availability in the aqueous phase might be increased and production of healthier crops can be accomplished. This research project aimed to achieve sustainable management of tropical agricultural soils, specifically in Puerto Rico, through the amendment of water treatment plant sludge’s. This practice avoids landfill disposal of sewage sludge and at the same time results cost-effective practice for recycling solid waste residues. Coriander sativum was cultivated in a compost-soil-sludge mixture at different proportions. Results showed that Coriander grown in a mixture of 25% compost+50% Voladora soi+25% sludge had the best growth and development. High chlorophyll content (33.01 ± 0.8) was observed in Coriander plants cultivated in 25% compost+62.5% Coloso soil+ 12.5% sludge compared to plants grown with no sludge (32.59 ± 0.7). ICP-OES analysis showed variations in mineral element contents (macro and micronutrients) in coriander plant grown I soil amended with sludge and compost.

Keywords: compost, Coriandrum sativum, nutrients, waste sludge

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Authors: Elena Listo, Miguel Marchamalo

Abstract:

This research studies the soil properties located in the watershed of Jabillo River in the Guanacaste province, Costa Rica. The soils are classified as Alfisols (T. Haplustalfs), in the flatter parts with grazing as Fluventic Haplustalfs or as a consequence of bad drainage as F. Epiaqualfs. The objective of this project is to define the status of the soil, to use remote sensing as a tool for analyzing the evolution of land use and determining the water balance of the watershed in order to improve the efficiency of the water collecting systems. Soil samples were analyzed from trial pits taken from secondary forests, degraded pastures, mature teak plantation, and regrowth -Tectona grandis L. F.- species developed favorably in the area. Furthermore, to complete the study, infiltration measurements were taken with an artificial rainfall simulator, as well as studies of soil compaction with a penetrometer, in points strategically selected from the different land uses. Regarding remote sensing, nearly 40 data samples were collected per plot of land. The source of radiation is reflected sunlight from the beam and the underside of leaves, bare soil, streams, roads and logs, and soil samples. Infiltration reached high levels. The majority of data came from the secondary forest and mature planting due to a high proportion of organic matter, relatively low bulk density, and high hydraulic conductivity. Teak regrowth had a low rate of infiltration because the studies made regarding the soil compaction showed a partial compaction over 50 cm. The secondary forest presented a compaction layer from 15 cm to 30 cm deep, and the degraded pasture, as a result of grazing, in the first 15 cm. In this area, the alfisols soils have high content of iron oxides, a fact that causes a higher reflectivity close to the infrared region of the electromagnetic spectrum (around 700mm), as a result of clay texture. Specifically in the teak plantation where the reflectivity reaches values of 90 %, this is due to the high content of clay in relation to others. In conclusion, the protective function of secondary forests is reaffirmed with regards to erosion and high rate of infiltration. In humid climates and permeable soils, the decrease of runoff is less, however, the percolation increases. The remote sensing indicates that being clay soils, they retain moisture in a better way and it means a low reflectivity despite being fine texture.

Keywords: alfisols, Costa Rica, infiltration, remote sensing

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Authors: Abubakar Aminu

Abstract:

Sand dunes, as a major product of desertification, is well known to affect soil resources, water resources and vegetation, especially in arid and semi-arid region; this scenario disrupt the livelihood security of people in the affected areas. The research assessed the episode of sand dune accumulation on water resources, soil and vegetation in Gada local government of Sokoto State, Nigeria. In this paper, both qualitative and quantitative methods were used to generate data which was analyzed and discussed. The finding of the paper shows that livelihood was affected by accumulations of sand dunes as water resources and soils were affected negatively thereby reducing crop yields and making livestock domestication a very difficult and expensive task; the finding also shows that 60% of the respondents agreed to planting of trees as the major solution to combat sand dunes accumulation. However, the soil parameters tested indicated low Organic carbon, low Nitrogen, low Potassium, Calcium and Phosphorus but higher values were recorded in Sodium and Cation exchange capacity which served as evidence of the high or strong aridity nature of the soil in the area. In line with the above, the researcher recommended a massive tree planting campaign to curtail desertification as well as using organic manures for higher agricultural yield and as such, improvement in livelihood security.

Keywords: soils, vegetatio, water, desertification

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Authors: Tamika Gordon

Abstract:

As technology continues to progress every second, educational institutions attempt to stay abreast of the latest developments through the acquisition of technological devices. Within schools, soft and hard technologies have assisted with reaching more students and expedient communication. As schools continue to grow, the need for simultaneous communication and efficient feedback has grown, and technology has allowed for these avenues to be explored and incorporated within a variety of daily operations. With the rapid inclusion of technology comes the potential for less face-to-face interactions among stakeholders. Although technology plays an integral role in education, the elements of both soft and hard technological devices must be proportionally utilized and coexist for the overall advancement and longevity of organizations. Over 20 articles were referenced to obtain a multitude of views on technology reflecting effects for students and teachers. Throughout this literature review, the effects of technology in the workplace will be discussed including views of current researchers, pros and cons surrounding technological inclusion, and implications for future research and further consideration. Upon the completion of the literature review, the benefits and necessity of technology remained high, however, low availability of resources, limited exposure to technological devices, and decreasing soft skills remained high as well. Recommendations are made for proportionate balances of technology and face-to-face interactions in order to minimize societal, educational, and organizational gaps.

Keywords: communication, devices, education, organizations, technology

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Authors: S. H. Chew, Z. X. Eng, K. E. Chuah, T. Y. Lim, H. M. A. Yim

Abstract:

In recent years, geotextile tube has been widely used in the hydraulic engineering and dewatering industry. To construct a stable containment bund with geotextile tubes, the sand slurry is always the preference infilling material. However, the shortage of sand supply posts a problem in Singapore to adopt this construction method in the actual construction of long containment bund. Hence, utilizing the soft dredged clay or the excavated soft clay as the infilling material of geotextile tubes has a great economic benefit. There are any technical issues with using this soft clayey material as infilling material, especially on the excessive settlement and stability concerns. To minimize the shape deformation and settlement of geotextile tube associated with the use of this soft clay infilling material, a modified innovative infilling material is proposed – lightly cemented soft clay. The preliminary laboratory studies have shown that the dewatering mechanism via geotextile material of the tube skin, and the introduction of cementitious chemical action of the lightly cemented soft clay will accelerate the consolidation and improve the shear strength of infill material. This study aims to extend the study by conducting a pilot test of the geotextile tube filled with lightly cemented clay. This study consists of testing on a series of miniature geo-tubes and two full-size geotextile tube. In the miniature geo-tube tests, a number of small scaled-down size of geotextile tubes were filled with cemented clay (at water content of 150%) with cement content of 0% to 8% (by weight). The shear strength development of the lightly cemented clay under dewatering mechanism was evaluated using a modified in-situ Cone Penetration Test (CPT) at 0 days, 3 days, 7 days and 28 days after the infilling. The undisturbed soil samples of lightly cemented infilled clay were also extracted at 3-days and 7-days for triaxial tests and evaluation of final water content. The results suggested that the geotextile tubes filled with un-cemented soft clay experienced very significant shape change over the days (as control test). However, geotextile mini-tubes filled with lightly cemented clay experienced only marginal shape changed, even that the strength development of this lightly cemented clay inside the tube may not show significant strength gain at the early stage. The shape stability is believed to be due to the confinement effect of the geotextile tube with clay at non-slurry state. Subsequently, a full-scale instrumented geotextile tube filled with lightly cemented clay was performed. The extensive results of strain gauges and pressure transducers installed on this full-size geotextile tube demonstrated a substantial mobilization of tensile forces on the geotextile skin corresponding to the filling activity and the subsequent dewatering stage. Shape change and the in-fill material strength development was also monitored. In summary, the construction of containment bund with geotextile tube filled with lightly cemented clay is found to be technically feasible and stable with the use of the sufficiently strong (i.e. adequate tensile strength) geotextile tube, the adequate control on the dosage of cement content, and suitable water content of infilling soft clay material.

Keywords: cemented clay, containment bund, dewatering, geotextile tube

Procedia PDF Downloads 264

Authors: Michelle Blewitt, Scott P. Wilson, Heidi Tait, Juniper Riordan

Abstract:

Rubber crumb is a physical and chemical pollutant of concern for the environment and human health, warranting immediate investigations into its pathways to the environment and potential impacts. This emerging microplastic is created by shredding end-of-life tyres into ‘rubber crumb’ particles between 1-5mm used on synthetic turf fields and soft-fall playgrounds as a solution to intensifying tyre waste worldwide. Despite having known toxic and carcinogenic properties, studies into the transportation pathways and movement patterns of rubber crumbs from these surfaces remain in their infancy. To address this deficit, AUSMAP, the Australian Microplastic Assessment Project, in partnership with the Tangaroa Blue Foundation, conducted a study to quantify crumb loss from soft-fall surfaces. To our best knowledge, this is the first of its kind, with funding for the audits being provided by the Australian Government’s Reef Trust. Sampling occurred at 12 soft-fall playgrounds within the Great Barrier Reef Catchment Area on Australia’s North-East coast, in close proximity to the United Nations World Heritage Listed Reef. Samples were collected over a 12-month period using randomized sediment cores at 0, 2 and 4 meters away from the playground edge along a 20-meter transect. This approach facilitated two objectives pertaining to particle movement: to establish that crumb loss is occurring and that it decreases with distance from the soft-fall surface. Rubber crumb abundance was expressed as a total value and used to determine an expected average of rubber crumb loss per m2. An Analysis of Variance (ANOVA) was used to compare the differences in crumb abundance at each interval from the playground. Site characteristics, including surrounding sediment type, playground age, degree of ultra-violet exposure and amount of foot traffic, were additionally recorded for the comparison. Preliminary findings indicate that crumb is being lost at considerable rates from soft-fall playgrounds in the region, emphasizing an urgent need to further examine it as a potential source of aquatic pollution, soil contamination and threat to individuals who regularly utilize these surfaces. Additional implications for the future of rubber crumbs as a fit-for-purpose recycling initiative will be discussed with regard to industry, governments and the economic burden of surface maintenance and/ or replacement.

Keywords: microplastics, toxic rubber crumb, litter pathways, marine environment

Procedia PDF Downloads 88