Search results for: carbide contaminated soils

Authors: Andres Mejia-Ortiz, Catalina Lozada, German R. Santos, Rafael Angulo-Jaramillo, Bernardo Caicedo

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The interaction between atmospheric variables and soil properties is a determining factor when evaluating the flow of water through the soil. This interaction situation directly determines the behavior of the soil and greatly influences the changes that occur in it. The atmospheric variations such as changes in the relative humidity, air temperature, wind velocity and precipitation, are the external variables that reflect a greater incidence in the changes that are generated in the subsoil, as a consequence of the water flow in descending and ascending conditions. These environmental variations have a major importance in the study of the soil because the conditions of humidity and temperature in the soil surface depend on them. In addition, these variations control the thickness of the unsaturated zone and the position of the water table with respect to the surface. However, understanding the relationship between the atmosphere and the soil is a somewhat complex aspect. This is mainly due to the difficulty involved in estimating the changes that occur in the soil from climate changes; since this is a coupled process where act processes of mass transfer and heat. In this research, an experimental field was implemented to study in-situ the interaction between the atmosphere and the soft soils of the city of Bogota, Colombia. The soil under study consists of a 60 cm layer composed of two silts of similar characteristics at the surface and a deep soft clay deposit located under the silky material. It should be noted that the vegetal layer and organic matter were removed to avoid the evapotranspiration phenomenon. Instrumentation was carried on in situ through a field disposal of many measuring devices such as soil moisture sensors, thermocouples, relative humidity sensors, wind velocity sensor, among others; which allow registering the variations of both the atmospheric variables and the properties of the soil. With the information collected through field monitoring, the water balances were made using the Hydrus-1D software to determine the flow conditions that developed in the soil during the study. Also, the moisture profile for different periods and time intervals was determined by the balance supplied by Hydrus 1D; this profile was validated by experimental measurements. As a boundary condition, the actual evaporation rate was included using the semi-empirical equations proposed by different authors. In this study, it was obtained for the rainy periods a descending flow that was governed by the infiltration capacity of the soil. On the other hand, during dry periods. An increase in the actual evaporation of the soil induces an upward flow of water, increasing suction due to the decrease in moisture content. Also, cracks were developed accelerating the evaporation process. This work concerns to the study of soil-atmosphere interaction through the experimental field and it is a very useful tool since it allows considering all the factors and parameters of the soil in its natural state and real values of the different environmental conditions.

Keywords: field monitoring, soil-atmosphere, soft soils, soil-water balance

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Authors: R. Pillai Aparna, S. R. Gandhi

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Soft clay deposits having low strength and high compressibility are found all over the world. Preloading with vertical drains is a widely used method for improving such type of soils. The coefficient of consolidation, irrespective of the drainage type, plays an important role in the design of vertical drains and it controls accurate prediction of the rate of consolidation of soil. Also, the increase in shear strength of soil with consolidation is another important factor considered in preloading or staged construction. To our best knowledge no clear guidelines are available to estimate the increase in shear strength for a particular degree of consolidation (U) at various stages during the construction. Various methods are available for finding out the consolidation coefficient. This study mainly focuses on the variation of, consolidation coefficient which was found out using different methods and shear strength with pressure intensity. The variation of shear strength with the degree of consolidation was also studied. The consolidation test was done using two types of highly compressible clays with vertical, radial and a few with combined drainage. The test was carried out at different pressures intensities and for each pressure intensity, once the target degree of consolidation is achieved, vane shear test was done at different locations in the sample, in order to determine the shear strength. The shear strength of clayey soils under the application of vertical stress with vertical and radial drainage with target U value of 70% and 90% was studied. It was found that there is not much variation in cv or cr value beyond 80kPa pressure intensity. Correlations were developed between shear strength ratio and consolidation pressure based on laboratory testing under controlled condition. It was observed that the shear strength of sample with target U value of 90% is about 1.4 to 2 times than that of 70% consolidated sample. Settlement analysis was done using Asaoka’s and hyperbolic method. The variation of strength with respect to the depth of sample was also studied, using large-scale consolidation test. It was found, based on the present study that the gain in strength is more on the top half of the clay layer, and also the shear strength of the sample ensuring radial drainage is slightly higher than that of the vertical drainage.

Keywords: consolidation coefficient, degree of consolidation, PVDs, shear strength

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Authors: Malory Jonata

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Chlordecone (CLD) is an organochlorine pesticide used between 1971 and 1993 in both Guadeloupe and Martinique for the control of banana black weevil. The bishomocubane structure which characterizes this chemical compound led to high stability in organic matter and high persistence in the environment. Recently, researchers found that CLD can be degraded by isolated bacteria consortiums and, particularly, by bacteria such as Citrobacter sp 86 and Delsulfovibrio sp 86. Actually, six transformation product families of CLD are known. Moreover, the latest discovery showed that CLD was disappearing faster than first predicted in highly contaminated soil in Guadeloupe. However, the toxicity of transformation products is still unknown, and knowledge has to be deepened on the degradation ways and chemical characteristics of chlordecone and its transformation products. Microbial fuel cells (MFC) are electrochemical systems that can convert organic matter into electricity thanks to electroactive bacteria. These bacteria can exchange electrons through their membranes to solid surfaces or molecules. MFC have proven their efficiency as bioremediation systems in water and soils. They are already used for the bioremediation of several organochlorine compounds such as perchlorate, trichlorophenol or hexachlorobenzene. In this study, a three-electrodes system, inspired by MFC, is used to try to degrade chlordecone using bacteria from a mangrove swamp in Martinique. As we know, some mangrove bacteria are electroactive. Furthermore, the CLD rate seems to decline in mangrove swamp sediments. This study aims to prove that electroactive bacteria from a mangrove swamp in Martinique can degrade CLD thanks to a three-electrodes bioelectrochemical system. To achieve this goal, the tree-electrodes assembly has been connected to a potentiostat. The substrate used is mangrove water and sediments sampled in the mangrove swamp of La Trinité, a coastal city in Martinique, where CLD contamination has already been studied. Electroactive biofilms are formed by imposing a potential relative to Saturated Calomel Electrode using chronoamperometry. Moreover, their comportment has been studied by using cyclic voltametry. Biofilms have been studied under different imposed potentials, several conditions of the substrate and with or without CLD. In order to quantify the evolution of CLD rates in the substrate’s system, gas chromatography coupled with mass spectrometry (GC-MS) was performed on pre-treated samples of water and sediments after short, medium and long-term contact with the electroactive biofilms. Results showed that between -0,8V and -0,2V, the three-electrodes system was able to reduce the chemical in the substrate solution. The first GC-MS analysis result of samples spiked with CLD seems to reveal decreased CLD concentration over time. In conclusion, the designed bioelectrochemical system can provide the necessary conditions for chlordecone degradation. However, it is necessary to improve three-electrodes control settings in order to increase degradation rates. The biological pathways are yet to enlighten by biologicals analysis of electroactive biofilms formed in this system. Moreover, the electrochemical study of mangrove substrate gives new informations on the potential use of this substrate for bioremediation. But further studies are needed to a better understanding of the electrochemical potential of this environment.

Keywords: bioelectrochemistry, bioremediation, chlordecone, mangrove swamp

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Authors: Venkatesan Sundaramoorthy

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The field of ceramics has undergone a remarkable transformation with the advent of additive manufacturing technologies. This comprehensive review explores the mechanical properties of additively manufactured ceramic components, focusing on key materials such as Alumina, Zirconia, and Silicon Carbide. The study delves into various authors' review technology into the various additive manufacturing techniques, including Stereolithography, Powder Bed Fusion, and Binder Jetting, highlighting their advantages and challenges. It provides a detailed analysis of the mechanical properties of these ceramics, offering insights into their hardness, strength, fracture toughness, and thermal conductivity. Factors affecting mechanical properties, such as microstructure and post-processing, are thoroughly examined. Recent advancements and future directions in 3D-printed ceramics are discussed, showcasing the potential for further optimization and innovation. This review underscores the profound implications of additive manufacturing for ceramics in industries such as aerospace, healthcare, and electronics, ushering in a new era of engineering and design possibilities for ceramic components.

Keywords: mechanical properties, additive manufacturing, ceramic materials, PBF

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Authors: M. Alsaadi, A. Erkliğ, M. Bulut

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This paper experimentally investigates the flexural and tensile properties of the industrial wastes sewage sludge ash (SSA) and fly ash (FA), and conventional ceramic powder silicon carbide (SiC) filled polyester composites. Four weight fractions (5, 10, 15 and 20 wt%) for each micro filler were used for production of composites. Then, test samples were produced according to ASTM. The resulting degree of particle dispersion in the polymer matrix was visualized by using scanning electron microscope (SEM). Results from this study showed that the tensile strength increased up to its maximum value at filler content 5 wt% of SSA, FA and SiC. Flexural strength increased with addition of particulate filler up to its maximum value at filler content 5 wt% of SSA and FA while for SiC decreased for all weight fractions gradually. The addition of SSA, FA and SiC fillers resulted in increase of tensile and flexural modulus for all the particulate composites. Industrial waste SSA can be used as an additive with polymer to produce composite materials.

Keywords: particle-reinforcement, sewage sludge ash, polymer matrix composites, mechanical properties

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Authors: Soma Ghosh, Balaram Mohapatra, Pinaki Sar, Abhijeet Mukherjee

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Microbial role in arsenic (As) mobilization in the groundwater aquifers of Brahmaputra river basin (BRB) in India, severely threatened by high concentrations of As, remains largely unknown. The present study, therefore, is a molecular and ecophysiological characterization of an indigenous bacterium strain IIIJ3-1 isolated from As contaminated groundwater of BRB and application of this strain in several microcosm set ups differing in their organic carbon (OC) source and terminal electron acceptors (TEA), to understand its role in As dissolution under aerobic and anaerobic conditions. Strain IIIJ3-1 was found to be a new facultative anaerobic, gram-positive, endospore-forming strain capable of arsenite (As3+) oxidation and dissimilatory arsenate (As5+) reduction. The bacterium exhibited low genomic (G+C)% content (45 mol%). Although, its 16S rRNA gene sequence revealed a maximum similarity of 99% with Bacillus cereus ATCC 14579(T) but the DNA-DNA relatedness of their genomic DNAs was only 49.9%, which remains well below the value recommended to delimit different species. Abundance of fatty acids iC17:0, iC15:0 and menaquinone (MK) 7 though corroborates its taxonomic affiliation with B. cereus sensu-lato group, presence of hydroxy fatty acids (HFAs), C18:2, MK5 and MK6 marked its uniqueness. Besides being highly As resistant (MTC=10mM As3+, 350mM As5+), metabolically diverse, efficient aerobic As3+ oxidizer; it exhibited near complete dissimilatory reduction of As5+ (1 mM). Utilization of various carbon sources with As5+ as TEA revealed lactate to serve as the best electron donor. Aerobic biotransformation assay yielded a lower Km for As3+ oxidation than As5+ reduction. Arsenic homeostasis was found to be conferred by the presence of arr, arsB, aioB, and acr3(1) genes. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis of this bacterium revealed reduction in cell size upon exposure to As and formation of As-rich electron opaque dots following growth with As3+. Incubation of this strain with sediment (sterilised) collected from BRB aquifers under varying OC, TEA and redox conditions revealed that the strain caused highest As mobilization from solid to aqueous phase under anaerobic condition with lactate and nitrate as electron donor and acceptor, respectively. Co-release of highest concentrations of oxalic acid, a well known bioweathering agent, considerable fold increase in viable cell counts and SEM-EDX and X-ray diffraction analysis of the sediment after incubation under this condition indicated that As release is consequent to microbial bioweathering of the minerals. Co-release of other elements statistically proves decoupled release of As with Fe and Zn. Principle component analysis also revealed prominent role of nitrate under aerobic and/or anaerobic condition in As release by strain IIIJ3-1. This study, therefore, is the first to isolate, characterize and reveal As mobilization property of a strain belonging to the Bacillus cereus sensu lato group isolated from highly As contaminated aquifers of Brahmaputra River Basin.

Keywords: anaerobic microcosm, arsenic rich electron opaque dots, Arsenic release, Bacillus strain IIIJ3-1

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Authors: Ayse Pekrioglu Balkis, Sawash Mecid

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Due to continued growth and rapid development of road construction in worldwide, road sub-layers consist of soil layers, therefore, identification and recognition of type of soil and soil behavior in different condition help to us to select soil according to specification and engineering characteristic, also if necessary sometimes stabilize the soil and treat undesirable properties of soils by adding materials such as bitumen, lime, cement, etc. If the soil beneath the road is not done according to the standards and construction will need more construction time. In this case, a large part of soil should be removed, transported and sometimes deposited. Then purchased sand and gravel is transported to the site and full depth filled and compacted. Stabilization by cement or other treats gives an opportunity to use the existing soil as a base material instead of removing it and purchasing and transporting better fill materials. Classification of soil according to AASHTOO system and USCS help engineers to anticipate soil behavior and select best treatment method. In this study soil classification and the relation between soil classification and stabilization method is discussed, cement stabilization with different percentages have been selected for soil treatment based on NCHRP. There are different parameters to define the strength of soil. In this study, CBR will be used to define the strength of soil. Cement by percentages, 0%, 3%, 7% and 10% added to soil for evaluation effect of added cement to CBR of treated soil. Implementation of stabilization process by different cement content help engineers to select an economic cement amount for the stabilization process according to project specification and characteristics. Stabilization process in optimum moisture content (OMC) and mixing rate effect on the strength of soil in the laboratory and field construction operation have been performed to see the improvement rate in strength and plasticity. Cement stabilization is quicker than a universal method such as removing and changing field soils. Cement addition increases CBR values of different soil types by the range of 22-69%.

Keywords: California Bearing Ratio, cement stabilization, clayey soil, mechanical properties

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Authors: Leonard Chimaobi Agim, Charles Arinzechukwu Igwe, Emmanuel Uzoma Onweremadu, Gabreil Osuji

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Soil erosion has been linked to stream sedimentation, ecosystem degradation, and loss of soil nutrients. A study was conducted to evaluate the effect of some organic amendment on sediment yield, splash loss, and runoff of soils of selected parent materials in southeastern Nigeria. A total of 20 locations, five from each of four parent materials namely: Asu River Group (ARG), Bende Ameki Group (BAG), Coastal Plain Sand (CPS) and Falsebedded Sandstone (FBS) were used for the study. Collected soil samples were analyzed with standard methods for the initial soil properties. Rainfall simulation at an intensity of 190 mm hr-1was conducted for 30 minutes on the soil samples at both the initial stage and after amendment to obtain erosion parameters. The influence of parent material on sediment yield, splash loss and runoff based on rainfall simulation was tested for using one way analyses of variance, while the influence of organic material and their combinations were a factorially fitted in a randomized complete block design. The organic amendments include; goat dropping (GD), poultry dropping (PD), municipal solid waste (MSW) and their combinations (COA) applied at four rates of 0, 10, 20 and 30 t ha-1 respectively. Data were analyzed using analyses of variance suitable for a factorial experiment. Significant means were separated using LSD at 5 % probability levels. Result showed significant (p ≤ 0.05) lower values of sediment yield, splash loss and runoff following amendment. For instance, organic amendment reduced sediment yield under wet and dry runs by 12.91 % and 26.16% in Ishiagu, 40.76% and 45.67%, in Bende, 16.17% and 50% in Obinze and 22.80% and 42.35% in Umulolo respectively. Goat dropping and combination of amendment gave the best results in reducing sediment yield.

Keywords: organic amendment, parent material, rainfall simulation, soil erosion

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Authors: J. Silva, P. Arezes, R. Schierl, N. Costa

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In order to study environmental contamination by cytostatic drugs in Portugal hospitals, sampling campaigns were conducted in three hospitals in 2015 (112 samples). Platinum containing drugs and fluorouracil were chosen because both were administered in high amounts. The detection limit was 0.01 pg/cm² for platinum and 0.1 pg/cm² for fluorouracil. The results show that spills occur mainly on the patient`s chair, while the most referenced occurrence is due to an inadequately closed wrapper. Day hospitals facilities were detected as having the largest number of contaminated samples and with higher levels of contamination.

Keywords: cytostatic, contamination, hospital, procedures, handling

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Authors: Fatemeh Benakashani, Hossein Tavakoli, Elias Soltani

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To ensure the sustainability of crop cultivation and rural economies, it is imperative that we focus on cultivating resilient crops capable of withstanding salt stress. However, the effective management of weeds in salt-affected soils remains a significant challenge. This study investigates the impact of living mulches, specifically Berseem clover (Trifolium alexandrinum) and Barley (Hordeum vulgare), on weed control, as well as the quality and yield of Black cumin (Nigella sativa) in salt-affected soil. In our research, we employed a two-fold mowing strategy for the living mulches: once following crop establishment and once before the flowering stage. Notably, the weed-free plots demonstrated Black cumin's seed yield, and oil content (31.1% to 34.3%), consistent with previous studies, highlighting its potential for the reclamation and utilization of salt-affected lands. However, Black cumin exhibited limited competitiveness against prevalent weeds in the field, such as Amaranthus retroflexus, Chenopodium album, and Portulaca oleracea, which significantly diminished both the 1000 grain mass in plots where weeds were present. Interestingly, the introduction of living mulches led to improvements in seed yield and seed oil content when compared to both weed-free and weed-infested plots. Notably, Berseem clover exhibited greater biomass than Barley, indicating its heightened competitiveness against weeds. Nevertheless, it's worth noting that in the long term, Berseem clover also competed with the main crop, thereby limiting overall productivity. Consequently, we recommend relocating the Berseem clover living mulch following the establishment of Black cumin as a strategy for weed management in Black cumin fields situated in salt-affected soils.

Keywords: weed management, competition, clover, barley, medicinal plant

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Authors: Azize Serap Tuncer

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Turkey is one of the most outstanding figures among the Mediterranean countries from the natural and historical point at view. It is relatively rich country as regards the flora and vegetation. But at the same time as a result of improper and unplanned usage of the land for centuries, its forests and fertile soils have been exposed to great damages. While rapid and uncontrolled urbanization has important effects on the environment, urban development legislations, have become very unsufficient for the protection of these areas. Some of them have been completely eradicated, and some others have lost their fertility. Besides Turkey has a high main land with a rough surface and its soils areas exposed to heavy erosion. On the other hand as a developing country, it is not willing to endanger the goals of industrialization and avoid foreign direct investment by implementing strict environmental policies. Although this kind of pressure on forestland resources threatens the stability of forest land and land use management, in recent years, there has been an obvious increase in public concern about environmental problems like over global warming, environmental pollution, deforestation and their potential effects on natural resources. To protect the ecological balance and prevention of naturel resources from the unplanned intervention of human-beıng is only possible establishing conservation areas wıth co-operation at the national and the internatıonal levels. This study was carried out to evaluate the relation between urbanization and forestry policies in Turkey. While it elaborates the normative arrangements resulting in power conflicts, it also addresses which shortages and discrepancies are responsible for the said conflicts. The present urban reconstruction and transformation practices and their aesthetic and functional aspects were studied with some examples in a country level and evaluated within the assistance of literature researches, analyses, and observations. Atatürk Forest Farm and ODTU Forest examples were negotiated as two famous cases. Obtained findings were supported by charts and photos.

Keywords: deforestration, environmental policies, metropolitan, pollution, urbanization

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Authors: Ali Reza Vaezi, Ouldouz Bakhshi Rad

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Gully erosion is a widespread and often dramatic form of soil erosion caused by water during and immediately after heavy rainfall. It occurs when flowing surface water is channelled across unprotected land and washes away the soil along the drainage lines. The formation of gully is influenced by various factors, including climate, drainage surface area, slope gradient, vegetation cover, land use, and soil properties. It is a very important problem in semi-arid regions, where soils have lower organic matter and are weakly aggregated. Intensive agriculture and tillage along the slope can accelerate soil erosion by water in the region. There is little information on the development of gully erosion in agricultural rainfed areas. Therefore, this study was carried out to investigate the relationship between gully erosion and morphometric characteristics of the drainage area and the effects of soil properties and soil management factors (land use and tillage method) on gully development. A field study was done in a 900 km2 agricultural area in Hshtroud township located in the south of East Azarbijan province, NW Iran. Toward this, two hundred twenty-two gullies created in rainfed lands were found in the area. Some properties of gullies, consisting of length, width, depth, height difference, cross section area, and volume, were determined. Drainage areas for each or some gullies were determined, and their boundaries were drawn. Additionally, the surface area of each drainage, land use, tillage direction, and soil properties that may affect gully formation were determined. The soil erodibility factor (K) defined in the Universal Soil Loss Equation (USLE) was estimated based on five soil properties (silt and very fine sand, coarse sand, organic matter, soil structure code, and soil permeability). Gully development in each drainage area was quantified using its volume and soil loss. The dependency of gully development on drainage area characteristics (surface area, land use, tillage direction, and soil properties) was determined using correlation matrix analysis. Based on the results, gully length was the most important morphometric characteristic indicating the development of gully erosion in the lands. Gully development in the area was related to slope gradient (r= -0.26), surface area (r= 0.71), the area of rainfed lands (r= 0.23), and the area of rainfed tilled along the slope (r= 0.24). Nevertheless, its correlation with the area of pasture and soil erodibility factor (K) was not significant. Among the characteristics of drainage area, surface area is the major factor controlling gully volume in the agricultural land. No significant correlation was found between gully erosion and soil erodibility factor (K) estimated by the Universal Soil Loss Equation (USLE). It seems the estimated soil erodibility can’t describe the susceptibility of the study soils to the gully erosion process. In these soils, aggregate stability and soil permeability are the two soil physical properties that affect the actual soil erodibility and in consequence, these soil properties can control gully erosion in the rainfed lands.

Keywords: agricultural area, gully properties, soil structure, USLE

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Authors: Onan Kilicaslan, Anil Kabaklarli, Levent Subasi, Erdem Bektas, Rifat Yilmaz

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The Aluminum-Copper casting alloys are well known for their high mechanical strength, especially when compared to more commonly used Aluminum-Silicon alloys. A201 is one of the best in terms of strength vs. weight ratio among other aluminum alloys, which makes it suitable for premium quality casting applications in aerospace and automotive industries. It is reported that A201 has low castability, but it is easy to machine. However, there is a need to specifically determine the process window for feasible machining. This research investigates the machinability of A201 alloy after T7 heat treatment in terms of chip/burr formation, surface roughness, hardness, and microstructure. The samples are cast with low-pressure sand casting method and milling experiments are performed with uncoated carbide tools using different cutting speeds and feeds. Statistical analysis is used to correlate the machining parameters to surface integrity. It is found that there is a strong dependence of the cutting conditions on machinability and a process window is determined.

Keywords: A201-T7, machinability, milling, surface integrity

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Authors: O. A. Apampa, Y. A. Jimoh

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The paper reports the investigation of Corn Cob Ash as a chemical stabilizing agent for laterite soils. Corn cob feedstock was obtained from Maya, a rural community in the derived savannah agro-ecological zone of South-Western Nigeria and burnt to ashes of pozzolanic quality. Reddish brown silty clayey sand material characterized as AASHTO A-2-6(3) lateritic material was obtained from a borrow pit in Abeokuta and subjected to strength characterization tests according to BS 1377: 2000. The soil was subsequently mixed with CCA in varying percentages of 0-7.5% at 1.5% intervals. The influence of CCA stabilized soil was determined for the Atterberg limits, compaction characteristics, CBR and the unconfined compression strength. The tests were repeated on laterite cement-soil mixture in order to establish a basis for comparison. The result shows a similarity in the compaction characteristics of soil-cement and soil-CCA. With increasing addition of binder from 1.5% to 7.5%, Maximum Dry Density progressively declined while the OMC steadily increased. For the CBR, the maximum positive impact was observed at 1.5% CCA addition at a value of 85% compared to the control value of 65% for the cement stabilization, but declined steadily thereafter with increasing addition of CCA, while that of soil-cement continued to increase with increasing addition of cement beyond 1.5% though at a relatively slow rate. Similar behavior was observed in the UCS values for the soil-CCA mix, increasing from a control value of 0.4 MN/m2 to 1.0 MN/m2 at 1.5% CCA and declining thereafter, while that for soil-cement continued to increase with increasing cement addition, but at a slower rate. This paper demonstrates that CCA is effective for chemical stabilization of a typical Nigerian AASHTO A-2-6 lateritic soil at maximum stabilizer content limit of 1.5% and therefore recommends its use as a way of finding further application for agricultural waste products and achievement of environmental sustainability in line with the ideals of the millennium development goals because of the economic and technical feasibility of the processing of the cobs from corn.

Keywords: corn cob ash, pozzolan, cement, laterite, stabilizing agent, cation exchange capacity

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Authors: A. Majeed, M.K. Abbasi, S. Hameed, A. Imran, T. Naqqash, M. K. Hanif

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Plant growth-promoting rhizobacteria (PGPR) are free-living soil bacteria that aggressively colonize the rhizosphere/plant roots, and enhance the growth and yield of plants when applied to seed or crops. Root associated (endophytic and rhizospheric) PGPR were isolated from Sunflower (Helianthus anus) grown in soils collected from 16 different sites of sub division Dhirkot, Poonch, Azad Jammu & Kashmir, Pakistan. A total of 150 bacterial isolates were isolated, purified, screened in vitro for their plant growth promoting (PGP) characteristics. 11 most effective isolates were selected on the basis of biochemical assays (nitrogen fixation, phosphate solubilization, growth hormone production, biocontrol assay, and carbon substrates utilization assay through gas chromatography (GCMS), spectrophotometry, high performance liquid chromatography HPLC, fungal and bacterial dual plate assay and BIOLOG GN2/GP2 microplate assay respectively) and were tested on the crop under controlled and field conditions. From the inoculation assay, the most promising 4 strains (on the basis of increased root/shoot weight, root/shoot length, seed oil content, and seed yield) were than selected for colonization studies through confocal laser scanning and transmission electron microscope. 16Sr RNA gene analysis showed that these bacterial isolates belong to Pseudononas, Enterobacter, Azospirrilum, and Citobacter genera. This study is the clear evident that such isolates have the potential for application as inoculants adapted to poor soils and local crops to minimize the chemical fertilizers harmful for soil and environment

Keywords: PGPR, nitrogen fixation, phosphate solubilization, colonization

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Authors: S. K. Kakraliya, H. S. Jat, Manish Kakraliya, P. C. Sharma, M. L. Jat

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The biggest challenge in agriculture is to produce more food for the continually increasing world population with in the limited land and water resources. Serious water deficits and reducing natural resources are some of the major threats to the agricultural sustainability in many regions of South Asia. Food and water security may be gained by bringing improvement in the crop water productivity and the amount produced per unit of water consumed. Improvement in the crop water productivity may be achieved by pursuing alternative modern agronomics approaches, which are more friendly and efficient in utilizing natural resources. Therefore, a research trial on conservation agriculture (CA) and precision water management (PWM) was conducted in 2018-19 at Karnal, India to evaluate the effect on crop productivity and irrigation in sodic soils under rice-wheat (RW) systems of Indo-Gangetic Plains (IGP). Eight scenarios were compared varied in the tillage, crop establishment, residue and irrigarion management i.e., {First four scenarios irrigated with flood irrigation method;Sc1-Conventional tillage (CT) without residue, Sc2-CT with residue, Sc3- Zero tillage (ZT) without residue, Sc4-ZT with residue}, and {last four scenarios irrigated with sub-surface drip irrigation method; Sc5-ZT without residue, Sc6- ZT with residue, Sc7-ZT inclusion legume without residue and Sc8- ZT inclusion legume with residue}. Results revealed that CA-flood irrigation (S3, Sc4) and CA-PWM system (Sc5, Sc6, Sc7 and Sc8) recorded about ~5% and ~15% higher wheat yield, respectively compared to Sc1. Similar, CA-PWM saved ~40% irrigation water compared to Sc1. Rice yield was not different under different scenarios in the first year (kharif 2019) but almost half irrigation water saved under CA-PWM system. Therefore, results of our study on modern agronomic practices including CA and precision water management (subsurface drip irrigation) for RW rotation would be addressed the existing and future challenges in the RW system.

Keywords: Sub-surface drip, Crop residue, Crop yield , Zero tillage

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Authors: K. N. Ashna

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Lightweight fills are a viable alternative where weak soils such as soft clay, peat, and loose silt are encountered. Materials such as Expanded Polystyrene (EPS) geo-foam, plastics, tire wastes, rubber wastes have been used along with soil in order to obtain a lightweight fill. Out of these, Expanded Polystyrene (EPS) geo-foam has gained wide popularity in civil engineering over the past years due to its wide variety of applications. It is extremely lightweight, durable and is available in various densities to meet the strength requirements. It can be used as backfill behind retaining walls to reduce lateral load, as a fill over soft clay or weak soils to prevent the excessive settlements and to reduce seismic forces. Geo-foam is available in block form as well as beads form. In this project Expanded Polystyrene (EPS) beads of various diameters and varying densities were mixed along with sand to study their lightweight as well as strength properties. Four types of EPS beads were used 1mm, 2mm, 3-7 mm and a mix of 1-7 mm. In this project, EPS beads were varied at .25%, .5%, .75% and 1% by weight of sand. A water content of 10% by weight of sand was added to prevent segregation of the mixture. Unconsolidated Unconfined (UU) tri-axial test was conducted at 100kPa, 200 kPa and 300 kPa and angle of internal friction, and cohesion was obtained. Unit weight of the mix was obtained for a relative density of 65%. The results showed that by increasing the EPS content by weight, maximum deviator stress, unit weight, angle of internal friction and initial elastic modulus decreased. An optimum EPS bead content was arrived at by considering the strength as well as the unit weight. The stress-strain behaviour of the mix was found to be dependent on type of bead, bead content and density of the beads. Finally, regression equations were developed to predict the initial elastic modulus of the mix.

Keywords: expanded polystyrene beads, geofoam, lightweight fills, stress-strain behavior, triaxial test

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Authors: Abdelmoniem A. Attaelmanan, Ahmed A. H. Siddig

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This study was conducted in light of continual global climate changes that projected increasing aridity, changes in soil fertility, and pollution. Plant growth and development largely depend on the combination of availing water and nutrients in the soil. Changes in the climate and atmospheric chemistry can cause serious effects on these growth factors. Plant carbon (C), nitrogen (N), and hydrogen (H) play a fundamental role in the maintenance of ecosystem structure and function. Hashab (Acacia senegal), which produces gum Arabic, supports dryland ecosystems in tropical zones by its potentiality to restore degraded soils; hence it is ecologically and economically important for the dry areas of sub-Saharan Africa. The study aims at investigating the effects of water stress (simulated drought) and poor soil type on Acacia senegal C, N, and H contents. Seven days old seedlings were assigned to the treatments in Split- plot design for four weeks. The main plot is irrigation interval (well-watered and water-stressed), and the subplot is soil types (silt and sand soils). Seedling's C%, N%, and H% were measured using CHNS-O Analyzer and applying Standard Test Method. Irrigation intervals and soil types had no effects on seedlings and leaves C%, N%, and H%, irrigation interval had affected stem C and H%, both irrigation intervals and soil types had affected root N% and interaction effect of water and soil was found on leaves and root's N%. Synthesis application of well-watered irrigation with soil that is rich in N and other nutrients would result in the greatest seedling C, N, and H content which will enhance growth and biomass accumulation and can play a crucial role in ecosystem productivity and services in the dryland regions.

Keywords: Acacia senegal, Africa, climate change, drylands, nutrients biomass, Sub-Saharan, Sudan

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Authors: Mohammad Reza Koushki Ardestani, Saeed Daneshmand, Mohammad Heydari Vini

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In the present study, AA7075/SiO2 composites have been fabricated via liquid metallurgy process. Using the degassing process, the wet ability of the molten aluminum alloys increased which improved the bonding between aluminum matrix and reinforcement (SiO2) particles. AA7075 alloy and SiO2 particles were taken as the base matrix and reinforcements, respectively. Then, contents of 2.5 and 5 wt. % of SiO2 subdivisions were added into the AA7075 matrix. To improve wettability and distribution, reinforcement particles were pre-heated to a temperature of 550°C for each composite sample. A uniform distribution of SiO2 particles was observed through the matrix alloy in the microstructural study. A hardened EN32 steel disc as the counter face was used to evaluate the wear rate pin-on-disc, a wear testing machine containing. The results showed that the wear rate of the AA/SiO2 composites was lesser than that of the monolithic AA7075 samples. Finally, The SEM worn surfaces of samples were investigated.

Keywords: Al7075, SiO₂, wear, composites, stir casting

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Authors: X. Vecino, J. M. Cruz, A. Moldes

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The disposal and the treatment of sewage sludge is an expensive and environmentally complex problem. In this work, a lipopeptide biosurfactant extracted from corn steep liquor was used as ecofriendly and cost-competitive alternative for the mobilization and bioremediation of fluorene in sewage sludge. Results have demonstrated that this biosurfactant has the capability to mobilize fluorene to the aqueous phase, reducing the amount of fluorene in the sewage sludge from 484.4 mg/Kg up to 413.7 mg/Kg and 196.0 mg/Kg after 1 and 27 days respectively. Furthemore, once the fluorene was extracted the lipopeptide biosurfactant contained in the aqueous phase allowed the bio-degradation, up to 40.5 % of the initial concentration of this polycyclic aromatic hydrocarbon.

Keywords: fluorene, lipopeptide biosurfactant, mobilization, sewage sludge

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Authors: Yuksel Akinay, Fatih Hayat

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The influence of the alloying element on mechanical properties and micro structures of the Fe-22Mn-0.6C-0,6Si twinning induced plasticity (TWIP) steel were investigated at different temperatures. This composition was fabricated by a vacuum induction melting method. This steel was homogenized at 1200◦C for 8h. After heat treatment it was hot-rolled at 1100◦C to 6 mm thickness. The hot rolled plates were cold rolled to 3 mm and annealed at 700 800 and 900 °C for 60 and 150 minute and then air-cooled. X-ray diffractometry (XRD), optic microscope and field emission scanning electron microscope (FESEM), hardness and tensile tests were used to analyse the relationship between mechanical properties and micro structure after annealing process. The results show that, the excellent mechanical properties were obtained after heat treatment process. The tensile strength of material was decreased and the ductility of material was improved with increasing annealing temperature. Ni element were increased the mechanical resistance of specimens and because of carbide precipitation the hardness of specimen annealed at 700 C is higher than others.

Keywords: high manganese, heat treatment, SEM, XRD, cold-rolling

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Authors: L. V. Lokesha, Jagadeesh S. Sanganal, Yogesh S. Gowda, Shekhar, N. B. Shridhar, N. Prakash, Prashantkumar Waghe, H. D. Narayanaswamy, Girish V. Kumar

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Organochlorine (OC) insecticides are among the most important organotoxins and make a large group of pesticides. Physicochemical properties of these toxins, especially their lipophilicity, facilitate the absorption and storage of these toxins in the meat thus possess public health threat to humans. The presence of these toxins in broiler meat can be a quantitative and qualitative index for the presence of these toxins in animal bodies, which is attributed to Waste water of irrigation after spraying the crops, contaminated animal feeds with pesticides, polluted air are the potential sources of residues in animal products. Fifty broiler meat samples were collected from different retail outlets of Bengaluru city, Karnataka state, in ice cold conditions and later stored under -20°C until analysis. All the samples were subjected to Gas Chromatograph attached to Electron Capture Detector(GC-ECD, VARIAN make) screening and quantification of OC pesticides viz; Alachlor, Aldrin, Alpha-BHC, Beta-BHC, Dieldrin, Delta-BHC, o,p-DDE, p,p-DDE, o,p-DDD, p,p-DDD, o,p-DDT, p,p-DDT, Endosulfan-I, Endosulfan-II, Endosulfan Sulphate and Lindane(all the standards were procured from Merck). Extraction was undertaken by blending fifty grams (g) of meat sample with 50g Sodium Sulphate anahydrous, 120 ml of n-hexane, 120 ml acetone for 15 mins, extract is washed with distilled water and sample moisture is dried by sodium sulphate anahydrous, partitioning is done with 25 ml petroleum ether, 10 ml acetonitrile and 15 ml n-hexane shake vigorously for two minutes, sample clean up was done with florosil column. The reconstituted samples (using n-hexane) (Merck chem) were injected to Gas Chromatograph–Electron Capture Detector(GC-ECD). The present study reveals that, among the fifty chicken samples subjected for analysis, 60% (15/50), 32% (8/50), 28% (7/50), 20% (5/50) and 16% (4/50) of samples contaminated with DDTs, Delta-BHC, Dieldrin, Aldrin and Alachlor respectively. DDT metabolites, Delta-BHC were the most frequently detected OC pesticides. The detected levels of the pesticides were below the levels of MRL(according to Export Council of India notification for fresh poultry meat).

Keywords: accuracy, gas chromatography, meat, pesticide, petroleum ether

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Authors: Diana Puigserver Cuerda, Jofre Herrero Ferran, José M. Carmona Perez

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In the transition zone between aquifers and basal aquitards, DNAPL-pools of chlorinated solvents are more recalcitrant than at other depths in the aquifer. Although degradation of carbon tetrachloride (CT) and chloroform (CF) occurs in this zone, this is a slow process, which is why an adequate remediation strategy is necessary. The working hypothesis of this study is that the biostimulation of the transition zone of an aquifer contaminated by CT and CF can be an effective remediation strategy. This hypothesis has been tested in a site on an unconfined aquifer in which the major contaminants were CT and CF of industrial origin and where the hydrochemical background was rich in other compounds that can hinder natural attenuation of chloromethanes. Field studies and five laboratory microcosm experiments were carried out at the level of groundwater and sediments to identify: i) the degradation processes of CT and CF; ii) the structure of microbial communities; and iii) the microorganisms implicated on this degradation. For this, concentration of contaminants and co-contaminants (nitrate and sulfate), Compound Specific Isotope Analysis, molecular techniques (Denaturing Gradient Gel Electrophoresis) and clone library analysis were used. The main results were: i) degradation processes of CT and CF occurred in groundwater and in the lesser conductive sediments; ii) sulfate-reducing conditions in the transition zone were high and similar to those in the source of contamination; iii) two microorganisms (Azospira suillum and a bacterium of the Clostridiales order) were identified in the transition zone at the field and lab experiments that were compatible with the role of carrying out the reductive dechlorination of CT, CF and their degradation products (dichloromethane and chloromethane); iv) these two microorganisms were present at the high starting concentrations of the microcosm experiments (similar to those in the source of DNAPL) and continued being present until the last day of the lactate biostimulation; and v) the lactate biostimulation gave rise to the fastest and highest degradation rates and promoted the elimination of other electron acceptors (e.g. nitrate and sulfate). All these results are evidence that lactate biostimulation can be effective in remediating the source and plume, especially in the transition zone, and highlight the environmental relevance of the treatment of contaminated transition zones in industrial contexts similar to that studied.

Keywords: Azospira suillum, lactate biostimulation of carbon tetrachloride and chloroform, reductive dechlorination, transition zone between aquifer and aquitard

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Authors: Chris M. Taylor, Ian Cook, Raul Alegre, Pedro Arrazola, Phil Spiers

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Noteworthy results have been obtained in the turning and drilling of hardened high-strength steels using tungsten carbide based cutting tools. In a finish turning process, it was seen that surface roughness and tool flank wear followed very different trends against cutting time. The suggested explanation for this behaviour is that the profile cut into the workpiece surface is determined by the tool’s cutting edge profile. It is shown that the profile appearing on the cut surface changes rapidly over time, so the profile of the tool cutting edge should also be changing rapidly. Workpiece material adhered onto the cutting tool, which is also known as a built-up edge, is a phenomenon which could explain the observations made. In terms of tool damage modes, workpiece material adhesion is believed to have contributed to tool wear in examples provided from finish turning, thread turning and drilling. Additionally, evidence of tool fracture and tool abrasion were recorded.

Keywords: turning, drilling, adhesion, wear, hard steels

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Authors: Sunil Mittal, Sukhpreet Singh, Hardeep Kaur

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A simple voltammetric technique for on-line analysis of arsenite [As (III)] is reported. Owing to the affinity of As (III) with thiol group of proteins and enzymes, cysteine has been employed as reducing agent. The reduction study of As(III)-cysteine complex on indium tin oxide (ITO) electrode has been explored. The experimental parameters such as scan rate, cysteine concentration, pH etc. were optimized to achieve As (III) determination. The developed method provided dynamic linear range of detection from 0.1 to 1 mM with a detection limit of 0.1 mM. The method is applicable to environmental monitoring of As (III) from highly contaminated sources such as industrial effluents, wastewater sludge etc.

Keywords: arsenite, cysteine, linear sweep voltammetry, reduction

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Authors: Bouchekoua Myriam, Aloui Dorsaf, Trabelsi Sonia

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Introduction Food hygiene in hospitals is important, particularly among patients who could be more vulnerable than healthy subjects to microbiological and nutritional risks. The consumption of contaminated food may be responsible for foodborne diseases, which can be severe among hospitalized patients, especially those immunocompromised. The aim of our study was to assess the state of hygiene in the internal catering department of a Tunisian hospital. Methodology and major results: A prospective study was conducted for one year in the Parasitology-Mycology laboratory of Charles Nicolle Hospital. Samples were taken from the kitchen staff, worktops, and cooking utensils used in the internal catering department. Thirty one employees have benefited from stool exams and scotch tape in order to evaluate the degree of infestation of parasites. 35% of stool exams were positive. Protozoa were the only parasites detected. Blastocystis sp was the species mostly found in nine food handlers. Its role as a human pathogen is still controversial. Pathogenic protozoa were detected in two food handlers (Giardia intestinalis in one person and Dientamoeba fragilis in the other one. Non-pathogenic protozoa were found in two cases; among them, only one had digestive symptoms without a statistically significant association with the carriage of intestinal parasites. Moreover, samples were performed from the hands of the staff in order to search for a fungal carriage. Thus, 25 employees (81%) were colonized by fungi, including molds. Besides, mycological examination among food handlers with a suspected dermatomycosis for diagnostic confirmation concluded foot onychomycosis in 32% of cases and interdigital intertrigo in 26%. Only one person had hand onychomycosis. Among the 17 samples taken from worktops and kitchen utensils, fungal contamination was detected in 13 sites. Hot and cold equipment were the most contaminated. Molds were mainly identified as belonging to five different genera. Cladosporium sp was predominant. Conclusion: In the view of the importance of intestinal parasites among food handlers, the intensity of fungi hand carriage among these employees, and the high level of fungal contamination in worktops and kitchen utensils, a reinforcement of hygiene measures is more than essential in order to minimize the alimentary contamination-risk.

Keywords: hospital kitchen, environment, intestinal parasitosis, fungal carriage, fungal contamination

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Authors: Omaima A. Sharaf, Tarek A. Moussa, Said M. Badr El-Din, H. Moawad

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Background: Polycyclic aromatic hydrocarbons (PAHs) pose great environmental and human health concerns for their widespread occurrence, persistence, and carcinogenic properties. PAHs releases due to anthropogenic activities to the wider environment have led to higher concentrations of these contaminants than would be expected from natural processes alone. This may result in a wide range of environmental problems that can accumulate in agricultural ecosystems, which threatened to become a negative impact on sustainable agricultural development. Thus, this study aimed to evaluate the physico-chemical, and microbial properties of the compost leachate (CL) to assess its role as nutrient and microbial source (biostimulation/bioaugmentation) for developing a cost-effective bioremediation technology for PAHs contaminated sites. Material and Methods: PAHs-degrading bacteria were isolated from CL that was collected from a composting site located in central Scotland, UK. Isolation was carried out by enrichment using phenanthrene (PHR), pyrene (PYR) and benzo(a)pyrene (BaP) as the sole source of carbon and energy. The isolates were characterized using a variety of phenotypic and molecular properties. Six different isolates were identified based on the difference in morphological and biochemical tests. The efficiency of these isolates in PAHs utilization was assessed. Further analysis was performed to define taxonomical status and phylogenic relation between the most potent PAHs-utilizing bacterial strains and other standard strains, using molecular approach by partial 16S rDNA gene sequence analysis. Results indicated that the 16S rDNA sequence analysis confirmed the results of biochemical identification, as both of biochemical and molecular identification of the isolates assigned them to Bacillus licheniformis, Pseudomonas aeruginosa, Alcaligenes faecalis, Serratia marcescens, Enterobacter cloacae and Providenicia which were identified as the prominent PAHs-utilizers isolated from CL. Conclusion: This study indicates that the CL samples contain a diverse population of PAHs-degrading bacteria and the use of CL may have a potential for bioremediation of PAHs contaminated sites.

Keywords: polycyclic aromatic hydrocarbons, physico-chemical analyses, compost leachate, microbial and biochemical analyses, phylogenic relations, 16S rDNA sequence analysis

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Authors: C. D. Gomez-Esparza, Z. V. Hernandez-Castro, C. A. Rodriguez-Gonzalez, R. Martinez-Sanchez, A. Duarte-Moller

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Recently, the high entropy alloys (HEA) are the focus of attention in metallurgical and materials science due to their desirable and superior properties in comparison to conventional alloys. The HEA field has promoted the exploration of several compositions including the addition of non-metallic elements like carbon, which in traditional metallurgy is mainly used in the steel industry. The aim of this work was the synthesis of equiatomic FeCrNiMnTi high entropy alloys, with minor carbon content, by mechanical alloying and sintering. The effect of the addition of carbon nanotubes and graphite were evaluated by X-ray diffraction, scanning electron microscopy, and microhardness test. The structural and microstructural characteristics of the equiatomic alloys, as well as their hardness were compared with those of an austenitic AISI 321 stainless steel processed under the same conditions. The results showed that porosity in bulk samples decreases with carbon nanotubes addition, while the equiatomic composition favors the formation of titanium carbide and increased the AISI 321 hardness more than three times.

Keywords: carbon nanotubes, graphite, high entropy alloys, mechanical alloying

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Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale

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It presents a heating system using low cost alternative solar collectors to promote the disinfection of water in low income communities that take water contaminated by bacteria. The system consists of two solar collectors, with total area of 4 m² and was built using PET bottles and cans of beer and soft drinks. Each collector is made up of 8 PVC tubes, connected in series and work in continuous flow. It will determine the flux the most appropriate to generate the temperature to promote the disinfection. Will be presented results of the efficiency and thermal loss of system and results of analysis of water after undergoing the process of heating.

Keywords: disinfection of water, solar heating system, poor communities, PVC

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Authors: Sheetal Sharma

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Urban planning is associated with land transformation from natural areas to modified and developed ones which leads to modification of natural environment. The basic knowledge of relationship between both should be ascertained before proceeding for the development of natural areas. Changes on land surface due to build up pavements, roads and similar land cover, affect surface water flow. There is a gap between urban planning and basic knowledge of hydrological processes which should be known to the planners. The paper aims to identify these variations in surface flow due to urbanization for a temporal scale of 40 years using Storm Water Management Mode (SWMM) and again correlating these findings with the urban planning guidelines in study area along with geological background to find out the suitable combinations of land cover, soil and guidelines. For the purpose of identifying the changes in surface flows, 19 catchments were identified with different geology and growth in 40 years facing different ground water levels fluctuations. The increasing built up, varying surface runoff are studied using Arc GIS and SWMM modeling, regression analysis for runoff. Resulting runoff for various land covers and soil groups with varying built up conditions were observed. The modeling procedures also included observations for varying precipitation and constant built up in all catchments. All these observations were combined for individual catchment and single regression curve was obtained for runoff. Thus, it was observed that alluvial with suitable land cover was better for infiltration and least generation of runoff but excess built up could not be sustained on alluvial soil. Similarly, basalt had least recharge and most runoff demanding maximum vegetation over it. Sandstone resulted in good recharging if planned with more open spaces and natural soils with intermittent vegetation. Hence, these observations made a keystone base for planners while planning various land uses on different soils. This paper contributes and provides a solution to basic knowledge gap, which urban planners face during development of natural surfaces.

Keywords: runoff, built up, roughness, recharge, temporal changes

Procedia PDF Downloads 278