Search results for: moisture damage

Authors: Parastou Kharazmi

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Degradation of building materials particularly pipelines causes environmental damage during the renovation or replacement, disturbance for people living in the buildings, is time-consuming and last but not least is very costly. Rehabilitation by composite materials is a solution for renovation of degraded pipeline in residential buildings and any other structures which is less costly, faster and causes less damage to the environment. This study provides a brief state of technology, methods, and materials which are being used in Nordic and some other European countries and an investigation on the performance of the relined pipes after they have been in working condition. The investigation was carried by different analyses in laboratory as well as numerous field inspections.

Keywords: buildings, pipeline, rehabilitation, polymer materials

Procedia PDF Downloads 216

Authors: Apolinar Picado, Ronald Solís, Rafael Gamero

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The thin-layer drying characteristics of instant coffee solution were investigated in a laboratory tunnel dryer. Drying experiments were carried out at three temperatures (80, 100 and 120 °C) and an air velocity of 1.2 m/s. Drying experimental data obtained are fitted to six (6) thin-layer drying models using the non-linear least squares regression analysis. The acceptability of the thin-layer drying model has been based on a value of the correlation coefficient that should be close to one, and low values for root mean square error (RMSE) and chi-square (x²). According to this evaluation, the most suitable model for describing drying process of thin-layer instant coffee solution is the Page model. Further, the effective moisture diffusivity and the activation energy were computed employing the drying experimental data. The effective moisture diffusivity values varied from 1.6133 × 10⁻⁹ to 1.6224 × 10⁻⁹ m²/s over the temperature range studied and the activation energy was estimated to be 162.62 J/mol.

Keywords: activation energy, diffusivity, instant coffee, thin-layer models

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Authors: Neda Nabid

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Friction-based supplemental devices have been extensively used for seismic protection and strengthening of structures, however, the conventional use of these dampers may not necessarily lead to an efficient structural performance. Conventionally designed friction dampers follow a uniform height-wise distribution pattern of slip load values for more practical simplicity. This can lead to localizing structural damage in certain story levels, while the other stories accommodate a negligible amount of relative displacement demand. A practical performance-based optimization methodology is developed to tackle with structural damage localization of RC frame buildings with friction energy dissipation devices under severe earthquakes. The proposed methodology is based on the concept of uniform damage distribution theory. According to this theory, the slip load values of the friction dampers redistribute and shift from stories with lower relative displacement demand to the stories with higher inter-story drifts to narrow down the discrepancy between the structural damage levels in different stories. In this study, the efficacy of the proposed design methodology is evaluated through the seismic performance of five different low to high-rise RC frames equipped with friction wall dampers under six real spectrum-compatible design earthquakes. The results indicate that compared to the conventional design, using the suggested methodology to design friction wall systems can lead to, by average, up to 40% reduction of maximum inter-story drift; and incredibly more uniform height-wise distribution of relative displacement demands under the design earthquakes.

Keywords: friction damper, nonlinear dynamic analysis, RC structures, seismic performance, structural damage

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Authors: Nadeem Munawar, Tariq Mahmood

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Habitat manipulation is an important technique that can be used for controlling rodent damage in agricultural ecosystems. It involves intentionally manipulation of vegetation cover in adjacent habitats around the active burrows of rodents to reduce shelter, food availability and to increase predation pressure. The current study was conducted in the Pothwar Plateau during the respective non-crop period of wheat-groundnut (post-harvested and un-ploughed/non-crop fallow lands) with the aim to assess the impact of the reduction in vegetation height of adjacent habitats (field borders) on rodent’s richness and abundance. The study area was divided into two sites viz. treated and non-treated. At the treated sites, habitat manipulation was carried out by removing crop cache, and non-crop vegetation’s over 10 cm in height to a distance of approximately 20 m from the fields. The trapping sessions carried out at both treated and non-treated sites adjacent to wheat-groundnut fields were significantly different (F 2, 6 = 13.2, P = 0.001) from each other, which revealed that a maximum number of rodents were captured from non-treated sites. There was a significant difference in the overall abundance of rodents (P < 0.05) between crop stages and between treatments in both crops. The manipulation effect was significantly observed on damage to crops, and yield production resulted in the reduction of damage within the associated croplands (P < 0.05). The outcomes of this study indicated a significant reduction of rodent population at treated sites due to changes in vegetation height and cover which affect important components, i.e., food, shelter, movements and increased risk sensitivity in their feeding behavior; therefore, they were unable to reach levels where they cause significant crop damage. This method is recommended for being a cost-effective and easy application.

Keywords: agricultural ecosystems, crop damage, habitat manipulation, rodents, trapping

Procedia PDF Downloads 132

Authors: Jessica Maiuolo, Irene Bava, Micaela Gliozzi, Vincenzo Mollace

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Doxorubicin is an anthracycline that is commonly used as a chemotherapy drug due to its cytotoxic effects. The clinical use of doxorubicin is limited due to its known cardiotoxic effects. Polyphenols have a wide range of beneficial properties, and particular importance is given to Oleuropein, one of the main polyphenolic compounds of olive oil. The biological mechanisms involved and the role of the endoplasmic reticulum were examined. Olive oil extract and Oleuropein were able to decrease the damage induced by exposure to doxorubicin. In particular, this natural compound was found to reduce cell mortality and oxidative damage, increase lipid content, and decrease the concentration of calcium ions that escaped from the endoplasmic reticulum. In addition, the direct involvement of this cellular organelle was demonstrated by silencing the ATF6 arm of the Unfolded Protein Response, which was activated after treatment with doxorubicin. The protection afforded by pre-treatment with the natural compound of interest, following the early damage induced by DOXO, provided valuable information regarding the potential use of these substances along with chemotherapy treatment.

Keywords: Olea europea L., oleuropein, doxorubicin, endoplasmic reticulum, nutraceutical support

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Authors: Eisa Y. Adam, Anas A. Fadlelmula, Ali E. Ali

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Sorghum head bug is a key insect pest of sorghum, and it is important to pay attention to the peak time of the pest abundance. The objective of this study was to study the effect of planting date on head bugs population. Field experiment was conducted during 2007/08 – 2008/09 and 2013/14 - 2014/15 cropping seasons at the Damazine Research Station Farm, Blue Nile State to determine sorghum head bugs incidence and abundance through the sowing date. Different sowing dates (early, mid and late sowing) and a susceptible sorghum variety known as Wad Ahmed variety were used the experiment. The experimental design used was randomized complete block design (RCBD). Data were collected on the number of head bug adults and nymphs/panicle, damage percent, coloration and a puncture due to bug feeding and oviposition, 1000 seeds weight and yield. The results showed that significantly (P<0.05) higher number of bugs and damage percent were recorded on the late sowing date for the four seasons followed by the mid sowing, while the early sowing gave low number of bugs, damage percent and high1000 weight. There were significant differences between protected and unprotected heads. The late sowing (August) is a critical sorghum planting time because it coincided with highest numbers of the head bugs.

Keywords: abundance, damage, headbugs, panicle

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Authors: Oladimeji Adetona Adeyeye, Emmanuel Rotimi Sadiku, Oluwaseun Olayinka Adeyeye

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In order to resuscitate soybean production and post-harvest processing especially, in term of threshing, there is need to develop an affordable threshing machine which will reduce drudgery associated with manual soybean threshing. Soybean thresher was fabricated and evaluated at Institute of Agricultural Research and Training IAR&T Apata Ibadan. The machine component includes; hopper, threshing unit, shaker, cleaning unit and the seed outlet, all working together to achieve the main objective of threshing and cleaning. TGX1835 - 10E variety was used for evaluation because of its high resistance to pests, rust and pustules. The final moisture content of the used sample was about 15%. The sample was weighed and introduced into the machine. The parameters evaluated includes moisture content, threshing efficiency, cleaning efficiency, machine capacity and speed. The threshing efficiency and capacity are 74% and 65.9kg/hr respectively. All materials used were sourced locally which makes the cost of production of the machine extremely cheaper than the imported soybean thresher.

Keywords: efficiency, machine capacity, speed, soybean, threshing

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Authors: M. N. Kadir, M. M. H. Oliver, T. Naher

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The study assesses the areal extent of riverine flood in the flood-prone area of Faridpur District of Bangladesh using hydrological model and Geographic Information System (GIS). In the context of preparing the inundation map, flood frequency analysis was carried out to assess flooding for different flood magnitudes. Flood inundation maps were prepared based on DEM, and discharge at the river using Delft-3D model. LANDSAT satellite images have been used to develop a land cover map in the study area. The land cover map was used for mapping of cropland area. By incorporating the inundation maps on the land cover map, agricultural damage was assessed. Present monetary values of crop damage were collected through field survey from actual flood of the study area. Two different inundation maps were produced from the model for the year 2000 and 2016. In the year 2000, the floods began in the month of July, whereas in the case of the year 2016 is started in August. Under both cases, most of the areas were found to have been flooded in the month of September followed by flood recession. In order to prepare the land cover maps, four categories of LCs were considered viz., cropland, water body, trees, and rivers. Among the 755791 acres area of Faridpur District, the croplands were categorized to be 334,589 acres, followed by water bodies (279900 acres), trees (101930 acres) and rivers 39372 (acres). Damage assessment data revealed that 40% of the total cropland area had been affected by the flood in the year 2000, whereas only 19% area was affected by the 2016 flood. The study concluded that September is the critical month for cropland protection since the highest flood is expected at this time of the year in Faridpur. The northwestern and the southwestern part of the district was categorized as most vulnerable to flooding.

Keywords: agricultural damage, Delft-3d, flood management, land cover map

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Authors: I. Hosni, L. Bennaceur Farah, N. Saber, R Bennaceur

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Soil moisture content is a key variable in many environmental sciences. Even though it represents a small proportion of the liquid freshwater on Earth, it modulates interactions between the land surface and the atmosphere, thereby influencing climate and weather. Accurate modeling of the above processes depends on the ability to provide a proper spatial characterization of soil moisture. The measurement of soil moisture content allows assessment of soil water resources in the field of hydrology and agronomy. The second parameter in interaction with the radar signal is the geometric structure of the soil. Most traditional electromagnetic models consider natural surfaces as single scale zero mean stationary Gaussian random processes. Roughness behavior is characterized by statistical parameters like the Root Mean Square (RMS) height and the correlation length. Then, the main problem is that the agreement between experimental measurements and theoretical values is usually poor due to the large variability of the correlation function, and as a consequence, backscattering models have often failed to predict correctly backscattering. In this study, surfaces are considered as band-limited fractal random processes corresponding to a superposition of a finite number of one-dimensional Gaussian process each one having a spatial scale. Multiscale roughness is characterized by two parameters, the first one is proportional to the RMS height, and the other one is related to the fractal dimension. Soil moisture is related to the complex dielectric constant. This multiscale description has been adapted to two-dimensional profiles using the bi-dimensional wavelet transform and the Mallat algorithm to describe more correctly natural surfaces. We characterize the soil surfaces and sub-surfaces by a three layers geo-electrical model. The upper layer is described by its dielectric constant, thickness, a multiscale bi-dimensional surface roughness model by using the wavelet transform and the Mallat algorithm, and volume scattering parameters. The lower layer is divided into three fictive layers separated by an assumed plane interface. These three layers were modeled by an effective medium characterized by an apparent effective dielectric constant taking into account the presence of air pockets in the soil. We have adopted the 2D multiscale three layers small perturbations model including, firstly air pockets in the soil sub-structure, and then a vegetable canopy in the soil surface structure, that is to simulate the radar backscattering. A sensitivity analysis of backscattering coefficient dependence on multiscale roughness and new soil moisture has been performed. Later, we proposed to change the dielectric constant of the multilayer medium because it takes into account the different moisture values of each layer in the soil. A sensitivity analysis of the backscattering coefficient, including the air pockets in the volume structure with respect to the multiscale roughness parameters and the apparent dielectric constant, was carried out. Finally, we proposed to study the behavior of the backscattering coefficient of the radar on a soil having a vegetable layer in its surface structure.

Keywords: multiscale, bidimensional, wavelets, backscattering, multilayer, SPM, air pockets

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Authors: Waleed Aly Sayed Ahmed, Eman Kishk, Tahani Shams

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Aim: To study the effects of co-administration of phosphodiesterase-5 inhibitor (PDE-5) and sodium selenite against the damage induced by ovarian ischemia-reperfusion in rats. Materials and Methods: A total of forty-two sexually mature, virgin, female rats were divided randomly into six groups of seven each: sham group (C), ischemia group (I), ischemia/reperfusion group (I/R), ischemia/reperfusion plus 1.4mg/kg sildenafil (I/R+S) group, ischemia/reperfusion plus 0.2mg/kg selenium (I/R+Se) group and ischemia/reperfusion plus combination of sildenafil and selenium (I/R+S+Se) group. In ischemia group (I), rats were exposed to ischemia for 3 hours (h). In ischemia/reperfusion group (I/R), rats were exposed to ischemia for 3 h followed by 6 h of reperfusion. Treated groups received 1.4mg/kg sildenafil or 0.2 mg/kg selenium or both 30 min before reperfusion. Both ovaries were surgically removed carefully. One ovary was examined for histopathological changes and the other was subject to biochemical analysis including malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx). Results: Assessment of ovarian tissue damage using a scoring system showed marked vascular congestion, interstitial edema, leukocyte infiltration, hemorrhage, and follicular degeneration in ischemia and ischemia/reperfusion groups. Tissue damage score for I, IR and all treated groups were significantly higher than those of the sham group (p<0.001), while tissue damage score decreased significantly in I/R+S and I/R+Se groups compared to I/R group (p<0.05), and notably, the difference was highly significant in I/R+S+Se group (p<0.001). There was significant increase in MDA levels and reduction in activities of CAT and GPx in I/R group compared to the sham group (p < 0.05). In I/R+S and I/R+Se groups, MDA was significantly decreased compared to the I/R group (p<0.05) and the difference was highly significant with co-administration of sildenafil and selenium (p<0.001). CAT and GPx were higher in all treated groups compared to I/R group (p<0.05). Conclusion: The co-administration of sildenafil citrate and selenium are highly protective against damage induced by ovarian ischemia/reperfusion in rats.

Keywords: phosphodiesterase-5 inhibitor, sildenafil, antioxidant, selenium, ovarian ischemia

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Authors: Felix Eyben, Simon Schaffrath, Markus Feldmann

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A building should maximize the potential for use through its design. Therefore, flexible use is always important when designing a steel structure. To create flexibility, steel beams with web openings are increasingly used, because these offer the advantage that cables, pipes and other technical equipment can easily be routed through without detours, allowing for more space-saving and aesthetically pleasing construction. This can also significantly reduce the height of ceiling systems. Until now, beams with web openings were not explicitly considered in the European standard. However, this is to be done with the new EN 1993-1-13, in which design rules for different opening forms are defined. In order to further develop the design concepts, beams with web openings under bending are therefore to be investigated in terms of damage mechanics as part of a German national research project aiming to optimize the verifications for steel structures based on a wider database and a validated damage prediction. For this purpose, first, fundamental factors influencing the load-bearing behavior of girders with web openings under bending load were investigated numerically without taking material damage into account. Various parameter studies were carried out for this purpose. For example, the factors under study were the opening shape, size and position as well as structural aspects as the span length, arrangement of stiffeners and loading situation. The load-bearing behavior is evaluated using resulting load-deformation curves. These results are compared with the design rules and critically analyzed. Experimental tests are also planned based on these results. Moreover, the implementation of damage mechanics in the form of the modified Bai-Wierzbicki model was examined. After the experimental tests will have been carried out, the numerical models are validated and further influencing factors will be investigated on the basis of parametric studies.

Keywords: damage mechanics, finite element, steel structures, web openings

Procedia PDF Downloads 139

Authors: Ajit Kumar Behera, Saranya P., Sudhir Kumar, Krishnakumar A

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The stable isotope (δ¹⁸ O and δ²H) composition of groundwater of the coastal areas of Periyar and Mahanadi basins falling along East and West coast of India during North-East (NE) monsoon season have been studied. The east and west coast regions are surrounded by the Bay of Bengal and the Arabian Sea respectively, which are considered to be the primary sources for precipitation over India. The major difference between the Bay of Bengal and the Arabian Sea is that a number of large rivers feed the Bay of Bengal, whereas the Arabian Sea is fed by very few small rivers, resulting in enriched stable isotopic composition of the Arabian Sea than the Bay of Bengal. Previous studies have reported depleted ratios of stable isotopes during Northeast monsoon along East and West coasts due to the influence of the Bay of Bengal moisture source. The isotopic composition of groundwater of the Mahanadi delta in the east coast region varies from -6.87 ‰ to -3.40 ‰ for δ¹⁸ O and -45.42 ‰ to -22.43‰ for δ²H. However, the groundwater of the Periyar basin in the west coast has enriched stable isotope value varying from -4.3‰ to -2.5 ‰ for δ¹⁸ O and for δ²H from -23.7 to -6.4 ‰ which is a characteristic of South-West monsoon season. This suggests the groundwater system of the Mahanadi delta and the Periyar basins are influenced by dissimilar moisture sources. The δ¹⁸ O and δ² H relationship (δ²H= 6.513 δ¹⁸ O - 1.39) and d-excess value (< 10) in the east coast region indicates the influence of NE monsoon implying the quick groundwater recharge after precipitation with significant amount of evaporation. In contrast, the δ¹⁸ O and δ²H regression line (δ²H= 8.408 δ¹⁸ O + 11.71) with high d-excess value (>10) in the west coast region implies delayed recharge due to SW monsoon. The observed isotopic enrichment in west coast suggests that NE winter monsoon rainfall does not replenish groundwater quick enough to produce isotopic depletion during the season.

Keywords: Arabian sea, bay of Bengal, groundwater, monsoon, stable isotope

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Authors: Laura Fernanda Pedreros Araque, Sebastian Rivera Pardo

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The massive removal phenomena have been one of the most frequent natural disasters in the world, causing thousands of deaths, victims, damage to homes and diseases. In Pitalito, and Campoalegre department of Huila municipalities - Colombia, disasters have occurred due to various events such as high rainfall, earthquakes; it has caused landslides, floods, among others, affected the economy, the community, and transportation. For this reason, a study was carried out on the area’s most prone to suffer these phenomena to take preventive measures in favor of the protection of the population, the resources of management, and the planning of civil works. For the proposed object, the Mora-Varshon method was used, which allows classifying the degree of susceptibility to landslides in which the areas are found. Also, various factors or parameters were evaluated such as the soil moisture, lithology, slope, seismicity, and rain, each of these indicators were obtained using information from IDEAM, Servicio Geologico Colombiano (SGC) and using geographic information for geoprocessing in the Arcgis software to realize a mapping to indicate the susceptibility to landslides, classifying the areas of the municipalities such as very low, low, medium, moderate, high or very high.

Keywords: geographic information system, landslide, mass removal phenomena, Mora-Varshon method

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Authors: Amitkumar R. Shelar, B. P. Ronge, Sridevi Seshabhattar, R. M. Wabale

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This paper gives knowledge about the behavior of cold rolled steel IS 513_2008 CR2_D having grade D for the reduction of ductile damage. CR specifies Cold Rolled and D for Drawing grade. Problems encountered during sheet metal forming operations are dent, wrinkles, thinning, spring back, insufficient stretching etc. In this paper, wrinkle defect was studied experimentally and by using FE software on one of the auto components due to which its functionality was decreased. Experimental result and simulation result were found to be in agreement.

Keywords: deep drawing, FE software-LS DYNA, friction, wrinkling

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Authors: Saeedullah J. Mandokhail, Meer H. Khan, Muhibullah Kakar

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The studies on the mechanical behavior of randomly distributed short fiber soil composite are relatively new technique in geotechnical engineering. In this paper, mechanically treated rice straw (MTRS) fiber is used to improve the engineering properties of clay. Clay was mixed with 0 %, 0.5 %, 1 % and 2 % of MTRS fiber to analyze the effect of MTRS fiber on properties of soil. It was found that the plasticity index of soil decreases with increase in the MTRS fiber. Cohesion and angle of internal friction of soil were also found to increase with limiting increase in the amount of MTRS fiber and then decreases. The maximum dry density slightly decreases and the optimum moisture content slightly increases with increasing amount of MTRS fibers.

Keywords: cohesion, friction angle, optimum moisture content, rice straw fiber, short fiber

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Authors: Mustafa Albayrak, Mete Onur Kaman, Ilyas Bozkurt

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In this study, the necessary material parameters were determined to be able to conduct progressive damage analysis of layered composites under low velocity impact by using the MAT162 material module in the LS-DYNA program. The material module MAT162 based on Hashin failure criterion requires 34 parameters in total. Some of these parameters were obtained directly as a result of dynamic and quasi-static mechanical tests, and the remaining part was calibrated and determined by comparing numerical and experimental results. Woven glass/epoxy was used as the composite material and it was produced by vacuum infusion method. In the numerical model, composites are modeled as three-dimensional and layered. As a result, the acquisition of MAT162 material module parameters, which will enable progressive damage analysis, is given in detail and step by step, and the selection methods of the parameters are explained. Numerical data consistent with the experimental results are given in graphics.

Keywords: Composite Impact, Finite Element Simulation, Progressive Damage Analyze, LS-DYNA, MAT162

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Authors: Mirco Tarozzi, Giacomo Pignagnoli, Andrea Benedetti

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The design of planning maintenance of civil structures often requires the evaluation of their level of safety in order to be able to choose which structure, and in which measure, it needs a structural retrofit. This work deals with the evaluation of the stiffness reduction of a scaled steel deck due to the presence of localized damages. The dynamic tests performed on it have shown the variability of its main frequencies linked to the gradual reduction of its rigidity. This deck consists in a steel grillage of four secondary beams and three main beams linked to a concrete slab. This steel deck is 6 m long and 3 m wide and it rests on two abutments made of concrete. By processing the signals of the accelerations due to a random excitation of the deck, the main natural frequencies of this bridge have been extracted. In order to assign more reliable parameters to the numerical model of the deck, some load tests have been performed and the mechanical property of the materials and the supports have been obtained. The two external beams have been cut at one third of their length and the structural strength has been restored by the design of a bolted plate. The gradual loss of the bolts and the plates removal have made the simulation of localized damage possible. In order to define the relationship between frequency variation and loss in stiffness, the identification of its natural frequencies has been performed, before and after the occurrence of the damage, corresponding to each step. The study of the relationship between stiffness losses and frequency shifts has been reported in this paper: the square of the frequency variation due to the presence of the damage is proportional to the ratio between the rigidities. This relationship can be used to quantify the loss in stiffness of a real scale bridge in an efficient way.

Keywords: damage detection, dynamic test, frequency shifts, operational modal analysis, steel bridge

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Authors: Sherly Shelton, Zhaohui Lin

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In recent decades, the inter-annual variability of summer precipitation over the India and Sri Lanka has intensified significantly with an increased frequency of both abnormally dry and wet summers. Therefore prediction of the inter-annual variability of summer precipitation is crucial and urgent for water management and local agriculture scheduling. However, none of the hypotheses put forward so far could understand the relationship to monsoon variability and related factors that affect to the South West Monsoon (SWM) variability in Sri Lanka. This study focused to identify the spatial and temporal variability of SWM rainfall events from June to September (JJAS) over Sri Lanka and associated trend. The monthly rainfall records covering 1980-2013 over the Sri Lanka are used for 19 stations to investigate long-term trends in SWM rainfall over Sri Lanka. The linear trends of atmospheric variables are calculated to understand the drivers behind the changers described based on the observed precipitation, sea surface temperature and atmospheric reanalysis products data for 34 years (1980–2013). Empirical orthogonal function (EOF) analysis was applied to understand the spatial and temporal behaviour of seasonal SWM rainfall variability and also investigate whether the trend pattern is the dominant mode that explains SWM rainfall variability. The spatial and stations based precipitation over the country showed statistically insignificant decreasing trends except few stations. The first two EOFs of seasonal (JJAS) mean of rainfall explained 52% and 23 % of the total variance and first PC showed positive loadings of the SWM rainfall for the whole landmass while strongest positive lording can be seen in western/ southwestern part of the Sri Lanka. There is a negative correlation (r ≤ -0.3) between SMRI and SST in the Arabian Sea and Central Indian Ocean which indicate that lower temperature in the Arabian Sea and Central Indian Ocean are associated with greater rainfall over the country. This study also shows that consistently warming throughout the Indian Ocean. The result shows that the perceptible water over the county is decreasing with the time which the influence to the reduction of precipitation over the area by weakening drawn draft. In addition, evaporation is getting weaker over the Arabian Sea, Bay of Bengal and Sri Lankan landmass which leads to reduction of moisture availability required for the SWM rainfall over Sri Lanka. At the same time, weakening of the SST gradients between Arabian Sea and Bay of Bengal can deteriorate the monsoon circulation, untimely which diminish SWM over Sri Lanka. The decreasing trends of moisture, moisture transport, zonal wind, moisture divergence with weakening evaporation over Arabian Sea, during the past decade having an aggravating influence on decreasing trends of monsoon rainfall over the Sri Lanka.

Keywords: Arabian Sea, moisture flux convergence, South West Monsoon, Sri Lanka, sea surface temperature

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Authors: Eun Gyeong Lee, Ji Young Park, Hyun Ae Woo

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Reactive oxygen species (ROS) production is involved in ischemia/reperfusion (I/R) injury in kidney of mice. Oxidative stress develops from an imbalance between ROS production and reduced antioxidant defenses. Many enzymatic and nonenzymatic antioxidant systems including peroxiredoxins (Prxs) are present in kidney to maintain an appropriate level of ROS and prevent oxidative damage. Prxs are a family of peroxidases that reduce peroxides, with a conserved cysteine residue serving as the site of oxidation by peroxides. In this study, we examined the protective role of Prx V against I/R-induced acute kidney injury (AKI) using Prx V wild type (WT) and knockout (KO) mice. We compared the response of Prx V WT and KO mice in mice model of I/R injury. Renal structure, functions, oxidative stress markers, protein levels of oxidative damage marker were worse in Prx V KO mice. Ablation of Prx V enhanced susceptibility to I/R-induced oxidative stress. Prx V KO mice were seen to have more severe renal damage than Prx V WT mice in mice model of I/R injury. Our results demonstrate that Prx V is protective against I/R-induced AKI.

Keywords: peroxiredoxin, ischemia/reperfusion, kidney, oxidative stress

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Authors: Manju, Praveen Aggarwal

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Clayey soil is considered weakest subgrade soil from civil engineering point of view under moist condition. These swelling soils attract and absorb water and losses their strength. Certain inherent properties of these clayey soils need modification for their bulk use in the construction of highways/runways pavements and embankments, etc. In this paper, results of clayey subgrade modified with cement stabilizer is presented. Investigation includes evaluation of specific gravity, Atterberg’s limits, grain size distribution, maximum dry density, optimum moisture content and CBR value of the clayey soil and cement treated clayey soil. A series of proctor compaction and CBR tests (un-soaked and soaked) are carried out on clayey soil and clayey soil mixed with cement stabilizer in 2%, 4% & 6% percentages to the dry weight of soil. In CBR test, under soaked condition best results are obtained with 6% of cement. However, the difference between the CBR value by addition of 4% and 6% cement is not much. Therefore from economical consideration addition of 4% cement gives the best result after soaking period of 90 days.

Keywords: clayey soil, cement, maximum dry density, optimum moisture content, California bearing ratio

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Authors: S. D. El Wakil, M. Pladsen

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Fiber reinforced polymeric (FRP) composites are finding wide-spread industrial applications because of their exceptionally high specific strength and specific modulus of elasticity. Nevertheless, it is very seldom to get ready-for-use components or products made of FRP composites. Secondary processing by machining, particularly drilling, is almost always required to make holes for fastening components together to produce assemblies. That creates problems since the FRP composites are neither homogeneous nor isotropic. Some of the problems that are encountered include the subsequent damage in the region around the drilled hole and the drilling – induced delamination of the layer of ply, that occurs both at the entrance and the exit planes of the work piece. Evidently, the functionality of the work piece would be detrimentally affected. The current work was carried out with the aim of eliminating or at least minimizing the work piece damage associated with drilling of FPR composites. Each test specimen involves a woven reinforced graphite fiber/epoxy composite having a thickness of 12.5 mm (0.5 inch). A large number of test specimens were subjected to drilling operations with different combinations of feed rates and cutting speeds. The drilling induced damage was taken as the absolute value of the difference between the drilled hole diameter and the nominal one taken as a percentage of the nominal diameter. The later was determined for each combination of feed rate and cutting speed, and a matrix comprising those values was established, where the columns indicate varying feed rate while and rows indicate varying cutting speeds. Next, the analysis of variance (ANOVA) approach was employed using Minitab software, in order to obtain the combination that would improve the drilling induced damage. Experimental results show that low feed rates coupled with low cutting speeds yielded the best results.

Keywords: drilling of composites, dimensional accuracy of holes drilled in composites, delamination and charring, graphite-epoxy composites

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Authors: B. Nakhostin-Roohi, F. Khoshkhahesh, KH. Parandak, R. Ramazanzadeh

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Introduction: The protective effect of antioxidants in diminishing the post-exercise rise of serum CK and LDH in individuals trained for competitive sports has come to light in recent years. This study was conducted to assess the effect of Two-week L-carnitine supplementation on exercise-induced muscle damage, as well as antioxidant capacity after a bout of strenuous exercise in active healthy young men. Methodology: Twenty active healthy men volunteered for this study. Participants were randomized in a double-blind placebo-controlled fashion into two groups: L-carnitine (C group; n = 10) and placebo group (P group; n = 10). The participants took supplementation (2000 mg L-carnitine) or placebo (2000 mg lactose) daily for 2weeks before the main trial. Then, participants ran 14 km. Blood samples were taken before supplementation, before exercise, immediately, 2h and 24h after exercise. Creatine kinase (CK), and lactate dehydrogenase (LDH), and total antioxidant capacity (TAC) were measured. Results: Serum CK and LDH significantly increased after exercise in both groups (p < 0.05). Serum LDH was significantly lower in C group than P group 2h and 24h after exercise (p < 0.05). Furthermore, CK was significantly lower in C group compared with P group just 24h after exercise (p < 0.05). Plasma TAC increased significantly 14 days after supplementation and 24h after exercise in C group compared with P group (p < 0.05). Discussion and conclusion: These results suggest two-week daily oral supplementation of L-carnitine has been able to promote antioxidant capacity before and after exercise and decrease muscle damage markers through possibly inhibition of exercise-induced oxidative stress.

Keywords: L-carnitine, muscle damage, creatine kinase, Lactate dehydrogenase

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Authors: Piotr Synaszko, Michał Sałaciński, Andrzej Leski

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This paper describes the analysis of construction Mi-2 helicopter rotor blades in order to determine the causes of appearance disbonds. Authors describe construction of rotor blade with impact on bonded joins and areas of water migration. They also made analysis which determines possibility of disbond between critical parts of rotor blades based on more than one hundred non-destructive inspections results. They showed which parts of the blades most likely to damage. The main source of damage is water presence.

Keywords: disbonds, environmental effect, helicopter rotor blades, service life extension

Procedia PDF Downloads 283

Authors: A. A. Bajad, B. P. Sharma, Y. C. Gupta, B. S. Dilt, R. K. Gupta

Abstract:

The present investigations were carried out at the experimental farm of Department of Floriculture and Landscape Architecture, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan, H.P. during 2015 and 2016. The experiment was laid out in a Randomized Block Design (factorial) consisting of 48 treatment combinations of four planting dates viz., D1- mid March, D2-mid April, D3-mid May and D4- mid June and two cultivars namely V1- Kamini and V2 -Poornima with six mulching materials M¬0¬- without mulch, M1- Black plastic mulch (100 µ), M2- Silver plastic mulch (100 µ), M3¬- Transparent plastic mulch (100 µ), M3-Transparent plastic mulch (100 µ), M4¬- Pine needle (100 µ) and M5- Grass (1 inch layer). Among different planting times, D4 i.e. mid June planting obtained best results for number of seed per flower (179.38), germination percent (83.92 %), electrical conductivity (0.97 ds/m), seedling length (7.93 cm), seedling dry weight (7.09 mg), seedling vigour index I (763.79), moisture content (7.83 %) and 1000 seed weight (1.94 g). However, seed yield per plant (14.30 g) was recorded to be maximum in mid of March. Among the cultivars, cv. ‘Poornima’ gave best results for number of seed per plant (187.30). However, cv. ‘Kamini’ recorded the best result for seed yield per plant (12.55), electrical conductivity (1.11 ds/m), germination percent (80.47 %), seedling length (6.39 cm), seedling dry weight (5.11 mg), seedling vigour index I (649.49), moisture content (9.28 %) and 1000 seed weight (1.70 g). Silver plastic obtained best results for number of seed per flower (170.10), seed yield per plant (15.66 g), germination percent (80.17 %), electrical conductivity (1.26 ds/m), seedling length (5.88 cm), seedling dry weight (4.46 mg), seedling vigour index I (616.78), Moisture content (9.35 %) and 100 seed weight (1.97 g).

Keywords: cultivars, mulch materials, planting times, flowers

Procedia PDF Downloads 238

Authors: Nour Aljafari, Mariam, S. Maani, Serter Atabay, Tarig Ali, Said Daker, Lara Daher, Hamad Bukhammas, Mohammed Abou Shakra

Abstract:

This paper aims at determining the soil characteristics that influence the irrigation process of green landscapes and deciding on the optimum amount of water needed for irrigation. The laboratory experiments were conducted using the constant head methodology to determine the soil infiltration rates. The steady state infiltration rate was reached after 10 minutes of infiltration at a rate of 200 mm/hr. The effects of different water heads on infiltration rates were also investigated, and the head of 11 cm was found to be the optimum head for the test. The experimental results showed consistent infiltration results for the range between 11 cm and 15 cm. The study also involved finding the initial moisture content, which ranged between 5% and 25%, and finding the organic content, which occupied 1% to 2% of the soil. These results will be later utilized, using the water balance approach, to estimate the optimum amount of water needed for irrigation for changing weather conditions.

Keywords: infiltration rate, moisture content, grass type, organic content

Procedia PDF Downloads 270

Authors: Kamile Nazan Turhan

Abstract:

When work on edible packaging began, the hope was to provide a sustainable alternative to reduce plastic consumption. Edible packaging can take the form of a coating or film that provides better protection of food. They have the potential to be a feasible alternative to traditional plastic food packaging as they can increase the shelf life of foods by reducing their respiration rate and water loss and protecting them from physical damage and microbial spoilage, preventing post-harvest loss. Edible films and coatings can extend the shelf life of the food product and improve food quality by regulating the transfer of moisture, oxygen, carbon dioxide, lipids, aroma and taste compounds in food systems. The main advantage of using edible packaging is that it reduces the amount of plastic waste produced. Another interesting advantage is that some edible food packaging elements may actually have added vitamins, probiotics and other nutrients, bioactive compounds that support technological and biological properties. Despite the use of many different biomaterials in the production of edible packaging, most of the problems experienced are similar. Among these problems: hydrophilicity, low water stability, high humidity sensitivity, poor resistance to moisture, high water vapor permeability, poor mechanical properties and machinability, fragility, insolubility, low melting point, sensitivity to ph, temperature, ionic, electro reactions, brittle. and hard structure, low thermal stability, hardness, hazy film are available. Edible films have the disadvantage of being difficult to apply to the food surface due to their weak barrier and mechanical properties.One of the most important problems is that the developed films have a brittle structure, since biomaterials are generally hydrophilic in nature. Plasticizer is added to increase the flexibility of the film, and as the plasticizer content increases, the film permeability also increases. The correct choice of plasticizer for a particular biopolymer allows optimization of the mechanical properties of the film with minimal increase in film permeability. The effect of the amount and type of plasticizer in achieving the desired mechanical properties with optimum permeability is constantly being investigated by researchers. However, it should be noted that in the studies conducted so far, plasticized biofilms cannot provide high mechanical strength or good flexibility compared to synthetic polymer materials. In this review, according to the results of the researches in the literature, the disadvantages of implementing edible packaging will be revealed and possible solutions will be presented.

Keywords: edible packaging, biyomateryal, disadvantages, production

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Authors: A. Chellil, A. Nour, S. Lecheb, H.Mechakra, A. Bouderba, H. Kebir

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In this paper, the numerical study for the instability of a composite rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor is developed. The use of the composite material for the rotor, offers a good Stability. Numerical calculations on the model develop of three dimensions prove that the damage effect has a negative effect on the stability of the rotor. The study of the composite rotor in transient system allowed to determine the vibratory responses due to various excitations.

Keywords: rotor, composite, damage, finite element, numerical

Procedia PDF Downloads 459

Authors: Juan Bojórquez, Sonia E. Ruiz, Edén Bojórquez, David de León Escobedo

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A life-cycle optimization procedure to establish the best load factors combinations for seismic design of buildings, is proposed. The expected cost of damage from future earthquakes within the life of the structure is estimated, and realistic cost functions are assumed. The functions include: Repair cost, cost of contents damage, cost associated with loss of life, cost of injuries and economic loss. The loads considered are dead, live and earthquake load. The study is performed for reinforced concrete buildings located in Mexico City. The buildings are modeled as multiple-degree-of-freedom frame structures. The parameter selected to measure the structural damage is the maximum inter-story drift. The structural models are subjected to 31 soft-soil ground motions recorded in the Lake Zone of Mexico City. In order to obtain the annual structural failure rates, a numerical integration method is applied.

Keywords: load factors, life-cycle analysis, seismic design, reinforced concrete buildings

Procedia PDF Downloads 592

Authors: Adu Micheal Kwaku, Lamptey Shirley

Abstract:

Cowpea (Vigna unguiculata (L.) Walpis) is a major food grain legume in Ghana and plays a significant role in consumer diets. Drought in rain-fed crop production is known to cause substantial crop yield reduction due to their negative impacts on plant growth, physiology, and reproduction. There are various ways of reducing the effect of drought or addressing the problem of drought stress, including irrigation, breeding, and mulching. Among these three ways of reducing the effect of drought stress, the cheapest and quickest method is mulching. The broad objective of this project is to determine the influence of mulching on the performance of cowpea. The experiment was conducted at Planting for future garden located at Nyankpala Campus of the University for Development Studies (UDS), comprising five treatments (black plastic, rice hull, groundnut hull, dry grass mulch, and control). The treatments were evaluated in a Randomized Complete Block Design (RCBD) with three replications. The result shows that black plastic mulch increased soil moisture by 1, 8, 15, and 24% compared to rice hull, groundnut hull, dry grass, and control, respectively. Increased soil moisture translated into black plastic mulch increasing grain yield by 8, 25, 39, and 46% compared to groundnut hull, rice hull, dry grass and control, respectively. However, black plastic mulch increased the cost of production, resulting in decreased net returns compared to the other treatment. This study recommends the use of rice and groundnut hull as mulching material to improve soil moisture, grain yield, and profit of smallholder cowpea farmers and also because they are almost free and available.

Keywords: mulch, plastic mulch, cowpea, growth response

Procedia PDF Downloads 56

Authors: Seung-Won Lee, JongSoo Lee, Won-Jik Yang, Hyung-Joon Kim

Abstract:

A capacity spectrum method (CSM), one of methodologies to evaluate seismic fragilities of building structures, has been long recognized as the most convenient method, even if it contains several limitations to predict the seismic response of structures of interest. This paper proposes the procedure to estimate seismic fragility curves using an incremental dynamic analysis (IDA) rather than the method adopting a CSM. To achieve the research purpose, this study compares the seismic fragility curves of a 5-story reinforced concrete (RC) moment frame obtained from both methods, an IDA method and a CSM. Both seismic fragility curves are similar in slight and moderate damage states whereas the fragility curve obtained from the IDA method presents less variation (or uncertainties) in extensive and complete damage states. This is due to the fact that the IDA method can properly capture the structural response beyond yielding rather than the CSM and can directly calculate higher mode effects. From these observations, the CSM could overestimate seismic vulnerabilities of the studied structure in extensive or complete damage states.

Keywords: seismic fragility curve, incremental dynamic analysis, capacity spectrum method, reinforced concrete moment frame

Procedia PDF Downloads 396