Search results for: height and diameter

Authors: Mohammed Ahmed Alghamdi, Hazem Mahmoud Ali Darwish, Mostafa Mohamed Abdelraheem

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Transparent conducting oxides (TCOs) possess low resistivity, exhibit good adherence to many substrates, and have good transmission characteristics from the visible to near-infrared wavelengths, which make it useful for various applications. Thin films of transparent conducting oxide (TCO’s) have received much attention because of their wide applications in the field of optoelectronic devices. Advancement of transparent conducting oxides TCO’s may not only lie within the improvement of existing materials in use, but also the development of novel materials. Solar cells are devices, which convert solar energy into electricity, either directly via the photovoltaic effect, or indirectly by first converting the solar energy to heat or chemical energy. Solar power has attracted attention of late as the most advanced of the alternative energy resources. The project aims to access the solar energy in Al-Baha region by search for materials (transparent-conductive oxides (TCO's)) to use in solar cells with highly transparent to the solar spectrum, have low electrical resistivity, be stable under H-plasma, and have a suitable structure in particular for a-Si solar cells. As the PV surface is exposed to the sunlight, the module temperature increases. High ambient temperatures along with long sunlight exposure time increases the temperature impact on PV cells efficiency. Since Al-Baha area is characterized by an atmosphere and pressure different from their counterparts in Saudi Arabia due to the height above sea level, hence it is appropriate to do studies to improve the efficiency of solar cells under these conditions. In this work, some ion change materials will be deposited using either sputtering/ or electron beam evaporation techniques. The optical properties of the synthesized materials will be studied in details for solar cell application. As we will study the effect of some dyes on the optical properties of the prepared films. The efficiency and other parameters of solar cell will be determined.

Keywords: thin films, solar cell, optical properties, electrical properties

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Authors: Çiğdem Sezer, Aksem Aksoy, Leyla Vatansever

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This study has been done for the purpose of evaluation of public health and identifying of enterotoxigenic Staphyloccocus aureus in kitchen of catering. In the kitchen of catering, samples have been taken by swabs from surface of equipments which are in the salad section, meat section and bakery section. Samples have been investigated with classical cultural methods in terms of Staphyloccocus aureus. Therefore, as a 10x10 cm area was identified (salad, cutting and chopping surfaces, knives, meat grinder, meat chopping surface) samples have been taken with sterile swabs with helping FTS from this area. In total, 50 samples were obtained. In aseptic conditions, Baird-Parker agar (with egg yolk tellurite) surface was seeded with swabs. After 24-48 hours of incubation at 37°C, the black colonies with 1-1.5 mm diameter and which are surrounded by a zone indicating lecithinase activity were identified as S. aureus after applying Gram staining, catalase, coagulase, glucose and mannitol fermentation and termonuclease tests. Genotypic characterization (Staphylococcus genus and S.aureus species spesific) of isolates was performed by PCR. The ELISA test was applied to the isolates for the identification of staphylococcal enterotoxins (SET) A, B, C, D, E in bacterial cultures. Measurements were taken at 450 nm in an ELISA reader using an Ridascreen-Total set ELISA test kit (r-biopharm R4105-Enterotoxin A, B, C, D, E). The results were calculated according to the manufacturer’s instructions. A total of 50 samples of 97 S. aureus was isolated. This number has been identified as 60 with PCR analysis. According to ELISA test, only 1 of 60 isolates were found to be enterotoxigenic. Enterotoxigenic strains were identified from the surface of salad chopping and cutting. In the kitchen of catering, S. aureus identification indicates a significant source of contamination. Especially, in raw consumed salad preparation phase of contamination is very important. This food can be a potential source of food-borne poisoning their terms, and they pose a significant risk to consumers have been identified.

Keywords: Staphylococcus aureus, enterotoxin, catering, kitchen, health

Procedia PDF Downloads 379

Authors: D. Dannehl, Z. Taylor, J. Suhl, L. Miranda, R., Ulrichs, C., Salazar, E. Fitz-Rodriguez, I. Lopez-Cruz, A. Rojano-Aguilar, G. Navas-Gomez, U. Schmidt

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Growing environmental and sustainability concerns have driven continual modernization of horticultural practices, especially for urban farming. Controlled environment and soilless production methods are increasing in popularity because of their efficient resource use and intensive cropping capabilities. However, some popular substrates used for hydroponic cultivation, particularly rock wool, represent a large environmental burden in regard to their manufacture and disposal. Substrate-less hydroponic systems are effective in producing short cropping cycle plants such as lettuce or herbs, but less information is available for the production of plants with larger root-systems and longer cropping times. Here, we investigated the viability of a hybrid aeroponic/nutrient film technique (AP/NFT) system for the cultivation of greenhouse tomatoes (Solanum lycopersicum ‘Panovy’). The plants grown in the AP/NFT system had a more compact phenotype, accumulated more Na⁺ and less P and S than the rock wool grown counterparts. Due to forced irrigation interruptions, we propose that the differences observed were cofounded by the differing severity of water-stress for plants with and without substrate. They may also be caused by a higher root zone temperature predominant in plants exposed to AP/NFT. However, leaf area, stem diameter, and number of trusses did not differ significantly. The same was found for leaf pigments and plant photosynthetic efficiency. Overall, the AP/NFT system appears to be viable for the production of greenhouse tomato, enabling the environment to be relieved by way of lessening rock wool usage.

Keywords: closed aeroponic systems, fruit quality, nutrient dynamics, substrate waste reduction, urban farming systems, water savings

Procedia PDF Downloads 253

Authors: Prakash Chandra Dhara, Rupa Maity, Mousumi Chatterjee

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Crowbars are used for the gardening purpose. The same tools are used by both male and female gardeners. The existing crowbars are suitable for the female gardeners. The present study was aimed to design a crowbar, which was required to use by the women for the gardening purpose, from the viewpoints of ergonomics. The study was carried out on 50 women in different villages of Howrah districts in West Bengal state. Different models of existing crowbars which were commonly used by the women were collected and evaluated by examining their shape and size. The problems of using existing crowbar were assessed by direct observation during its operation. The musculoskeletal disorder of the subjects for using the crowbar was evaluated by modified Nordic questionnaire method. The anthropometric dimensions, especially hand dimension, of the subjects were taken in standardized static conditions. Considering the problems of using the existing crowbars some design concepts were developed and accordingly three prototypes models (P1, P2, P3) of crowbar were prepared for designing of a modified crowbar for women. Psychophysical analysis of those prototypes was made by paired comparison tests. In the above test subjective preference for different characteristics of the crowbar, e.g., length, weight, length and breadth of the blade, handle diameter, position of the handle, were determined. From the results of the paired comparison test and percentile values of hand dimensions, a modified design of crowbar was suggested. The prototype model P1 possessed more preferred characteristics of the tool than that of other prototype models. In the final design, the weight of the tool and length of the blade was reduced from that of the existing crowbar. Other dimensions were also changed. Two handles were suggested in the redesigned tool for better gripping and operation. The modified crowbar was evaluated by studying the body joint angles, viz., wrist, shoulder and elbow, for assessing the suitability of the design. It was concluded that the redesigned crowbar was suitable for women’s use.

Keywords: body dimension, crowbar, ergo-design, women, hand anthropometry

Procedia PDF Downloads 233

Authors: Sachin Pawar, Suman Patra, Goutam Mukhopadhyay

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The primary function of a shaft is to transfer power. The shaft can be cast or forged and then machined to the final shape. Manufacturing of ~5 m length and 0.6 m diameter shaft is very critical. More difficult is to maintain its straightness during heat treatment and machining operations, which involve thermal and mechanical loads, respectively. During the machining operation of a such forged mandrel shaft, a deflection of 3-4mm was observed. To remove this deflection shaft was pressed at both ends which led to the development of cracks in it. To investigate the root cause of the deflection and cracking, the sample was cut from the failed shaft. Possible causes were identified with the help of a cause and effect diagram. Chemical composition analysis, microstructural analysis, and hardness measurement were done to confirm whether the shaft meets the required specifications or not. Chemical composition analysis confirmed that the material grade was 42CrMo4. Microstructural analysis revealed the presence of untempered martensite, indicating improper heat treatment. Due to this, ductility and impact toughness values were considerably lower than the specification of the mentioned grade. Residual stress measurement of one more bent shaft manufactured by a similar route was done by portable X-ray diffraction(XRD) technique. For better understanding, measurements were done at twelve different locations along the length of the shaft. The occurrence of a high amount of undesirable tensile residual stresses close to the Ultimate Tensile Strength(UTS) of the material was observed. Untempered martensitic structure, lower ductility, lower impact strength, and presence of a high amount of residual stresses all confirmed the improper tempering heat treatment of the shaft. Tempering relieves the residual stresses. Based on the findings of this study, stress-relieving heat treatment was done to remove the residual stresses and deflection in the shaft successfully.

Keywords: residual stress, mandrel shaft, untempered martensite, portable XRD

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Authors: Anthony Khawaja, Jacques Prioux, Ghassan Maalouf, Rawad El Hage

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The regular practice of physical activities characterized by significant mechanical stresses stimulates bone formation and improves bone mineral density (BMD) in the most solicited sites. The purpose of this study was to explore the relationships between maximum power and bone variables in a group of young adult men. Identification of new determinants of BMD, bone mineral content (BMC) and hip geometric indices in young adult men, would allow screening and early management of future cases of osteopenia and osteoporosis. Fifty-three young adult men (18 – 35yr) voluntarily participated in this study. Weight and height were measured, and body mass index was calculated. Body composition, BMC and BMD were determined for each individual by Dual-energy X-ray absorptiometry (DXA; GE Healthcare, Madison, WI) at whole body (WB), lumbar spine (L1-L4), total hip (TH), and femoral neck (FN). FN cross-sectional area (CSA), strength index (SI), buckling ratio (BR), FN section modulus (Z), cross-sectional moment of inertia (CSMI) and L1-L4 TBS were also evaluated by DXA. The vertical jump was evaluated using a field test (sargent test). Two main parameters were retained: vertical jump performance (cm) and power (w). The subjects performed three jumps with 2 minutes of recovery between jumps. The highest vertical jump was selected. Maximum power (P max, in watts) was calculated. Maximum power was positively correlated to WB BMD (r = 0.41; p < 0.01), WB BMC (r = 0.65; p < 0.001), L1-L4 BMC (r = 0.54; p < 0.001), FN BMC (r = 0.35; p < 0.01), TH BMC (r = 0.50; p < 0.001), CSMI (r = 0.50; p < 0.001), CSA (r = 0.33; p < 0.05). Vertical jump was positively correlated to WB BMC (r = 0.31; p < 0.05), L1-L4 BMC (r = 0.40; p < 0.01), CSMI (r = 0.29; p < 0.05). The current study suggests that maximum power is a positive determinant of BMD, BMC and hip geometric indices in young adult men. In addition, it shows also that maximum power is a stronger positive determinant of bone variables than vertical jump in this population. Implementing strategies to increase maximum power in young adult men may be useful for preventing osteoporotic fractures later in life.

Keywords: bone variables, maximum power, osteopenia, osteoporosis, vertical jump, young adult men

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Authors: Dawei Shen, Ming Xu, Pengfei Liu

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The joints between simply supported bridge decks and abutments need to be regularly repaired, which would greatly increase the cost during the service life of the bridge. Simply supported girder bridges suffered the most severe damage during earthquakes. Another type of bridge, the integral bridge, of which the superstructure and abutment are rigidly connected, was also used in some European countries. Because no bearings or joints exit in the integral bridge, this type of bridge could significantly reduce maintenance requirements and costs. However, conventional integral bridge usually result in high earth pressure on the abutment and surface settlement in the backfill. To solve these problems, a new type of integral bridge, geosynthetic-reinforced soil (GRS) integral bridge, was come up in recent years. This newly invented bridge has not been used in engineering practices. There was a lack of research on the seismic behavior of the conventional and new type of integral abutments. In addition, no common design code could be found for the calculation of seismic pressure of soil behind the abutment. This paper developed a dynamic constitutive model, which can consider the soil behaviors under cyclic loading. Numerical analyses of the seismic response of a full height integral bridge and GRS integral bridge were carried out using the two-dimensional numerical code, FLAC. A parametric study was also performed to investigate the soil-structure interaction. The results are presented below. The seismic responses of GRS integral bridge together with conventional simply supported bridge, GRS conventional bridge and conventional integral bridge were investigated. The results show that the GRS integral bridge holds the highest seismic stability, followed by conventional integral bridge, GRS simply supported bridge and conventional simply supported bridge. Compared with the integral bridge with 1 m thick abutments, the GRS integral bridge with 0.4 m thick abutments is subjected to a smaller bending moment, and the natural frequency and horizontal displacement remains almost the same. Geosynthetic-reinforcement will be more effective when the abutment becomes thinner or the abutment is higher.

Keywords: geosynthetic-reinforced soil integral bridge, nonlinear hysteretic model, numerical analysis, seismic response

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Authors: Ying Deng, Fan Yang

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Aim: To study the growth pattern of preterm infants during the first year of life and explore the association between head circumference (HC) and neurodevelopment sequences and to get a general knowledge of the incidence of anemia in preterm babies in Chengdu, Southwest China. Method: We conducted a prospective longitudinal study, neonates with gestational age < 37 weeks were enrolled this study from 2012.1.1 to 2014.7.9. Anthropometry (weight, height, HC) was obtained at birth, every month before 6 months-old and every 2 months in the next half year. All the infants’ age were corrected to 40 weeks. Growth data presented as Z-scores which was calculated by WHO Anthro software. Z-score defined as (the actual value minus the average value)/standard deviation. Neurodevelopment was assessed at 12 months-old [9-11 months corrected age (CA)] by using “Denver Development Screen Test (DDST)". The hemoglobin (Hb) was examined at 6 months for CA. Result: 445 preterm infants were followed-up 1 year, including 64 very low birth weight infants (VLBW), 246 low birth weight infants (LBW) and 135 normal birth weight infants(NBW). From full-term to 12 months after birth, catch-up growth was observed in most preterm infants. From VLBW to NBW, HCZ was -1.17 (95 % CI: -1.53,-0.80; P value < 0.0001) lower during the first12 months. WAZ was-1.12(95 % CI: -1.47,-0.76; p < 0.0001) lower. WHZ and HAZ were -1.04 (95%CI:-1.38, -0.69; P<0.0001) and -0.69 (95%CI:-1.06,-0.33; P < 0.0001) lower respectively. The peak of WAZ appeared during 0-3 months CA among preterm infants. For VLBW infants, the peak of HAZ and HCZ emerged at 8-11 months CA. However, the trend of HAZ and HCZ is the same as WAZ in LBW and NBW infants. Growth in the small for gestational age (SGA) infants was poorer than appropriate for gestational age (AGA) infants. The rate of DQ < 70 in VLBW and LBW were 29.6%, 7.7%, respectively (P < 0.0001). HCZ < -1SD at 3 months emerged as an independent predictor of DQ scores below 85 at 12 months after birth. The incidence of anemia in preterm infants was 11% at 6 months for CA. Moreover, 7 children (1.7%) diagnosed with Cerebral palsy (CP). Conclusions: The catch-up growth was observed in most preterm infants. VLBW and SGA showed poor growth. There was imbalance between WAZ and HAZ in VLBW infants. The VLBW babies had higher severe abnormal scores than LBW and NBW, especially in boys. Z score for HC at 3 months < -1SDwas a significant risk factor for abnormal DQ scores at the first year. The iron supplement reduced the morbidity of anemia in preterm infants.

Keywords: preterm infant, growth and development, DDST, Z-scores

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Authors: A. Kabir, D. Boulainine, I. Bouanane, N. Benslim, B. Boudjema, C. Sedrati

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SnO₂ is an n-type semiconductor with a direct gap of about 3.6 eV. It is largely used in several domains such as nanocrystalline photovoltaic cells. Due to its interesting physic-chemical properties, this material was elaborated in thin film forms using different deposition techniques. It was found that SnO₂ properties were directly affected by the deposition method parameters. In this work, the RGTO method (Rheotaxial Growth and Thermal Oxidation) was used to deposit elaborate SnO₂ thin films. This technique consists on thermal oxidation of the Sn films deposited onto a substrate heated to a temperature close to Sn melting point (232°C). Such process allows the preparation of high porosity tin oxide films which are very suitable for the gas sensing. The films structural, morphological and optical properties pre and post thermal oxidation were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) respectively. XRD patterns showed a polycrystalline structure of the cassiterite phase of SnO₂. The grain growth was found affected by the oxidation temperature. This grain size evolution was confronted to existing grain growth models in order to understand the growth mechanism. From SEM images, the as deposited Sn film was formed of difference diameter spherical agglomerations. As a function of the oxidation temperature, these spherical agglomerations shape changed due to the introduction of oxygen ions. The deformed spheres started to interconnect by forming bridges between them. The volume porosity, determined from the UV-Visible reflexion spectra, Changes as a function of the oxidation temperature. The variation of the crystalline fraction, determined from FTIR spectra, correlated with the variation of both the grain size and the volume porosity.

Keywords: tin oxide, RGTO, grain growth, volume porosity, crystalline fraction

Procedia PDF Downloads 248

Authors: Sabeen Alam, Mehboob Alam

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The research work entitled “Effect of Bacillus pumilus strains on heavy metal accumulation in lettuce grown on contaminated soil” focused on functional role of Bacillus pumilus strains inoculated with lettuce seed in mitigating heavy metal in chromite mining soil. In this experiment, factor A was three Bacillus pumilus strains (sequence C-2PMW-8, C-1 SSK-8 and C-1 PWK-7) while soil used for this experiment was collected from Prang Ghar mining site and lettuce seeds were grown in three levels of chromite mining soil (2.27, 4.65 and 7.14 %). For mining soil minimum days to germinate noted in lettuce grown on garden soil inoculated with sequence. Maximum germination percentage noted was for C-1 SSK-8 grown on garden soil, maximum lettuce height for sequence C-2 PWM-8, fresh leaf weight for C-1 PWK-7 inoculated lettuce, dry weight of lettuce leaf for lettuce inoculated with C-1 SSK-8 and C-1 PWK-7 strains, number of leaves per plant for lettuce inoculated with C-1 SSK-8, leaf area for C-2 PMW-8 inoculated lettuce, survival percentage for C-1 SSK-8 treated lettuce and chlorophyll content for C-2 PMW-8. Results related to heavy metals accumulation showed that minimum chromium was in lettuce and in soil for all three sequences, cadmium (Cd) in lettuce and in soil for all three sequences, manganese (Mn) in lettuce and in soil for three sequences, lead (Pb) in lettuce and in soil for three sequences. It can be concluded that chromite mining soil significantly reduced the growth and survival of lettuce, but when lettuce was inoculated with Bacillus.pumilus strains, it enhances growth and survival. Similarly, minimum heavy metal accumulation in plant and soil, regardless of type of Bacillus pumilus used, all three sequences has same mitigating effect on heavy metal in both soil and lettuce. All the three Bacillus pumilus strains ensured reduction in heavy metals content (Mn, Cd, Cr) in lettuce, below the maximum permissible limits of WHO 2011.

Keywords: bacillus pumilus, heavy metals, permissible limits, lettuce, chromite mining soil, mitigating effect

Procedia PDF Downloads 37

Authors: Yasuyuki Takahashi, Hirotaka Shimada, Kyoko Saito

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Bone scintigraphy is widely used as a screening tool for bone metastases. However, the 180 to 240 minutes (min) waiting time after the intravenous (i.v.) injection of the tracer is both long and tiresome. To solve this shortcoming, a bone scan with a shorter waiting time is needed. In this study, we applied the Maximum Intensity Projection (MIP) and triple energy window (TEW) scatter correction to a whole body bone SPECT (Merged SPECT) and investigated shortening the waiting time. Methods: In a preliminary phantom study, hot gels of 99mTc-HMDP were inserted into sets of rods with diameters ranging from 4 to 19 mm. Each rod set covered a sector of a cylindrical phantom. The activity concentration of all rods was 2.5 times that of the background in the cylindrical body of the phantom. In the human study, SPECT images were obtained from chest to abdomen at 30 to 180 min after 99mTc- hydroxymethylene diphosphonate (HMDP) injection of healthy volunteers. For both studies, MIP images were reconstructed. Planar whole body images of the patients were also obtained. These were acquired at 200 min. The image quality of the SPECT and the planar images was compared. Additionally, 36 patients with breast cancer were scanned in the same way. The delectability of uptake regions (metastases) was compared visually. Results: In the phantom study, a 4 mm size hot gel was difficult to depict on the conventional SPECT, but MIP images could recognize it clearly. For both the healthy volunteers and the clinical patients, the accumulation of 99mTc-HMDP in the SPECT was good as early as 90 min. All findings of both image sets were in agreement. Conclusion: In phantoms, images from MIP with TEW scatter correction could detect all rods down to those with a diameter of 4 mm. In patients, MIP reconstruction with TEW scatter correction could improve the detectability of hot lesions. In addition, the time between injection and imaging could be shortened from that conventionally used for whole body scans.

Keywords: merged SPECT, MIP, TEW scatter correction, 99mTc-HMDP

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Authors: Reza Mehrafarin, Nafiseh Mirshekari, Mahyar Mehrafarin

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In 25 km southeast of Zabul (center of Sistan, in the east of Iran), a large hill can be seen. This hill, which is located next to the bend of the Sistan river, is known as the Tappeh Shahrestan. The length of the Tappeh Shahrestan is 1350 meters, its width is 360 meters, and its height is 20 meters, which in total reaches to 48 hectares. The capital of Sistan province was Ram Shahrestan in the Sassanid period, according to Iranian historical texts and Sassanid Pahlavi traditions. The city was abandoned because the nearby river dried up. Then another capital was built in Sistan called Zarang. But due to the long passage of time since the destruction of the city, its real location was forgotten and and some archaeologists have suggested different areas as the main location of the Ram Shahrestan. In 2018, the first archaeological field activities took place on and around the hillin order to answer this question: was Tappe Shahristan the same as Ram Shahristan, the capital of Sistan, during the Sassanid period? In order to answer this question, archaeological field activities were carried out on and around the hill. The field activities of the first season included the followings: 1- Preparation of hill topography and plan metric 3-Archaeogeophysics studies 3-Methodical study of archeology 4-Determining the range of the hill by soundings5-Documentation of the hill 6-Classification, typology, and comparison of pottery typology. The results of archaeological field activities in the first phase of Tappeh Shahrestan showed that this ancient site was the same city of Ram Shahrestan, the capital of Sistan, during the Sassanid period. The beginning of settlement in this city was the third century BC and the time of leaving was the end of the third century AD. The most important factors in the creation of the city was the abundant water of the Sistan River and its convenient location, and the most important reason for the abandonment of the city was the Sistan River, whose water completely dried up.

Keywords: archaeological surveys, archaeological soundings, ram shahrestan, sistan, tappeh shahrestan

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Authors: Omvati Verma, Shyamashrre Roy

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A field experiment was conducted with three basal nitrogen levels (90, 120 and 150 kg N/ha) and five foliar application of urea (absolute control, water spray, 3% urea spray at anthesis, 7 and 14 days after anthesis) at G.B. Pant University of Agriculture & Technology, Pantnagar, U.S. Nagar (Uttarakhand) during rabi season in a factorial randomized block design with three replications. Results revealed that nitrogen application of 150 kg/ha produced the highest seed yield, straw and biological yield and it was significantly superior to 90 kg N/ha and was at par with 120 kg N/ha. The number of tillers increased significantly with increase in nitrogen doses up to 150 kg N/ha. Spike length, number of grains per spike, grain weight per spike and thousand seed weight showed significantly higher values with 120 kg N/ha than 90 kg N/ha and were at par with that of 150 kg N/ha. Also, plant height showed similar trend. Leaf area index and chlorophyll content showed significant increase with an increase in nitrogen levels at different stages. In the case of foliar spray treatments, urea spray at anthesis showed highest value for yield and yield attributes. In case of spike length and thousand seed weight, it was similar with the urea spray at 7 and 14 days after anthesis, but for rest of the yield attributes, it was significantly higher than rest of the treatments. Among seed quality parameters protein and sedimentation value showed significant increase due to increase in nitrogen rates whereas, starch and hectolitre weight had a decreasing trend. Wet gluten content was not influenced by nitrogen levels. Foliar urea spray at anthesis resulted in highest value of protein and hectolitre weight whereas, urea spray at 7 days after anthesis showed highest value of sedimentation value and wet gluten content.

Keywords: foliar application, nitrogenous fertilizer, seed quality, yield

Procedia PDF Downloads 258

Authors: Mehrak Zargaryaeghoubi, Masood Hajali

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Drilled shafts are the most popular of deep foundations, because they have the capability that one single shaft can easily carry the entire load of a large column from a bridge or tall building. Drilled shaft may be an economical alternative to pile foundations because a pile cap is not needed, which not only reduces that expense, but also provides a rough surface in the border of soil and concrete to carry a more axial load. Due to the larger construction sizes of drilled shafts, they have an excellent axial load carrying capacity. Part of the axial load carrying capacity of the drilled shaft is resisted by the soil below the tip of the shaft which is tip resistance and the other part is resisted by the friction developed around the drilled shaft which is side resistance. The condition at the bottom of the excavation can affect the end bearing capacity of the drilled shaft. Also, type of the soil and size of the drilled shaft can affect the frictional resistance. The main loads applied on the drilled shafts are axial compressive loads. It is important to know how many percent of the maximum applied load will be shed inside friction and how much will be transferred to the base. The axial capacity of the drilled shaft foundation is influenced by the size of the drilled shaft, and soil characteristics. In this study, the effect of the size and soil characteristic will be investigated on the contribution of side resistance and end-bearing capacity. Also, the study presents a three-dimensional finite element modeling of a drilled shaft subjected to axial load using ANSYS. The top displacement and settlement of the drilled shaft are verified with analytical results. The soil profile is considered as Table 1 and for a drilled shaft with 7 ft diameter and 95 ft length the stresses in z-direction are calculated through the length of the shaft. From the stresses in z-direction through the length of the shaft the side resistance can be calculated and with the z-direction stress at the tip, the tip resistance can be calculated. The result of the side and tip resistance for this drilled shaft are compared with the analytical results.

Keywords: Drilled Shaft Foundation, size and soil characteristic, axial load capacity, Finite Element

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Authors: Sherif D. El Wakil, John Rice

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The aim of the current work was to employ the finite element method to model a slab, with a small hole across its width, undergoing plastic plane strain deformation. The computational model had, however, to be validated by comparing its results with those obtained experimentally. Since they were in good agreement, the finite element method can therefore be considered a reliable tool that can help gain better understanding of the mechanism of ductile failure in structural members having stress raisers. The finite element software used was ANSYS, and the PLANE183 element was utilized. It is a higher order 2-D, 8-node or 6-node element with quadratic displacement behavior. A bilinear stress-strain relationship was used to define the material properties, with constants similar to those of the material used in the experimental study. The model was run for several tensile loads in order to observe the progression of the plastic deformation region, and the stress concentration factor was determined in each case. The experimental study involved employing the visioplasticity technique, where a circular mesh (each circle was 0.5 mm in diameter, with 0.05 mm line thickness) was initially printed on the side of an aluminum slab having a small hole across its width. Tensile loading was then applied to produce a small increment of plastic deformation. Circles in the plastic region became ellipses, where the directions of the principal strains and stresses coincided with the major and minor axes of the ellipses. Next, we were able to determine the directions of the maximum and minimum shear stresses at the center of each ellipse, and the slip-line field was then constructed. We were then able to determine the stress at any point in the plastic deformation zone, and hence the stress concentration factor. The experimental results were found to be in good agreement with the analytical ones.

Keywords: finite element method to model a slab, slab undergoing plastic deformation, stress distribution around a circular hole, visioplasticity

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Authors: Syed Ibrahim, Syed Muneer Ahmed

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It is a global phenomenon that fitness is a pre-requisite to the desired end of optimum efficiency in elite class basketballers achieved through appropriate conditioning program. This study was undertaken to find out the effect of gymnastic oriented training program on the physical fitness and the level of technical performance of basketball players. Method: 27 basketballers were divided into 12 experimental and 15 control groups aged between 19 to 25 years. Physical fitness tests comprising of vertical jump, push-ups, chin ups, sit ups, back strength, 30 m sprint, boomerangs test, 600 m run, sit and reach, bridge up and shoulder rotation and technical skill tests like dribbling, layup shots and rebound collection were used for the study. A pre- and post-test was conducted before and after the training program of 6 weeks. Results: The results indicated no significant difference in the anthropometric measurements of age, height and weight between the experimental and control group as the ‘t’ values observed were 0.28, 1.63 and 1.60 respectively . There were significant improvements in vertical jump, push-ups, sit-ups, modified boomerang test, bridge test and shoulder rotation index with the ‘t’ values being 2.60, 3.41, 3.91, 4.02, 3.55 and 2.33 respectively. However, no significant differences existed in chin-ups, back strength, 30 m sprint and 6000 m run with the ‘t’ values being 2.08, 1.77, 1.28 and 0.80 respectively. There was significant improvement in the post-test for the technical skills tests in the experimental group with ‘t’ values being 3.65, 2.57, and 3.62 for the dribble, layup shots and rebound collection respectively. There was no significant difference in the values of the control group except in the rebound collection which showed significant difference. Conclusion: It was found that both the physical fitness and skill proficiency of the basketballers increased through the participation in the gymnastics oriented program.

Keywords: gymnastic, technical, pre-requisite, elite class

Procedia PDF Downloads 384

Authors: Mitra Saberi, Saeideh Fakhari, Amir Karam, Ali Ahmadabadi

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Geomorphology is the scientific study of the characteristics of form and shape of the Earth's surface. The existence of types of landforms and their variation is mainly controlled by changes in the shape and position of land and topography. In fact, the interest and application of fractal issues in geomorphology is due to the fact that many geomorphic landforms have fractal structures and their formation and transformation can be explained by mathematical relations. The purpose of this study is to identify and analyze the fractal behavior of landforms of macro geomorphologic regions of Iran, as well as studying and analyzing topographic and landform characteristics based on fractal relationships. In this study, using the Iranian digital elevation model in the form of slopes, coefficients of deposition and alluvial fan, the fractal dimensions of the curves were calculated through the box counting method. The morphometric characteristics of the landforms and their fractal dimension were then calculated for 4criteria (height, slope, profile curvature and planimetric curvature) and indices (maximum, Average, standard deviation) using ArcMap software separately. After investigating their correlation with fractal dimension, two-way regression analysis was performed and the relationship between fractal dimension and morphometric characteristics of landforms was investigated. The results show that the fractal dimension in different pixels size of 30, 90 and 200m, topographic curves of different landform units of Iran including mountain, hill, plateau, plain of Iran, from1.06in alluvial fans to1.17in The mountains are different. Generally, for all pixels of different sizes, the fractal dimension is reduced from mountain to plain. The fractal dimension with the slope criterion and the standard deviation index has the highest correlation coefficient, with the curvature of the profile and the mean index has the lowest correlation coefficient, and as the pixels become larger, the correlation coefficient between the indices and the fractal dimension decreases.

Keywords: box counting method, fractal dimension, geomorphology, Iran, landform

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Authors: M. Manohari, S. Priyadharshini, K. Bajeer Sulthan, R. Santhanam, S. Chandrasekaran, B. Venkatraman

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In-vivo monitoring facility at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, caters to the monitoring of internal exposure of occupational radiation workers from various radioactive facilities of IGCAR. Internal exposure measurement is done using Na(Tl) based Scintillation detectors. Two types of whole-body counters, namely Shielded Chair Counter (SC) and Standing Whole-Body Monitor (SWBM), are being used. The shielded Chair is based on a NaI detector of 20.3 cm diameter and 10.15 cm thick. The chair of the system is shielded using lead shots of 10 cm lead equivalent and the detector with 8 cm lead bricks. Counting geometry is sitting geometry. Calibration is done using 95 percentile BOMAB phantom. The minimum Detectable Activity (MDA) for 137Cs for the 60s is 1150 Bq. Standing Wholebody monitor (SWBM) has two NaI(Tl) detectors of size 10.16 x 10.16 x 40.64 cm3 positioned serially, one over the other. It has a shielding thickness of 5cm lead equivalent. Counting is done in standup geometry. Calibration is done with the help of Ortec Phantom, having a uniform distribution of mixed radionuclides for the thyroid, thorax and pelvis. The efficiency of SWBM is 2.4 to 3.5 times higher than that of the shielded chair in the energy range of 279 to 1332 keV. MDA of 250 Bq for 137Cs can be achieved with a counting time of 60s. MDA for 131I in the thyroid was estimated as 100 Bq from the MDA of whole-body for one-day post intake. Standing whole body monitor is better in terms of efficiency, MDA and ease of positioning. In case of emergency situations, the optimal MDAs for in-vivo monitoring service are 1000 Bq for 137Cs and 100 Bq for 131I. Hence, SWBM is more suitable for the rapid screening of workers as well as the public in the case of an emergency. While a person reports for counting, there is a potential for external contamination. In SWBM, there is a feasibility to discriminate them as the subject can be counted in anterior or posterior geometry which is not possible in SC.

Keywords: minimum detectable activity, shielded chair, shielding thickness, standing whole body monitor

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Authors: Dipak Sen, Rajdeep Ghosh

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This paper presents a computational study of steady state three dimensional very high turbulent flow and heat transfer characteristics in a constant temperature-surfaced circular duct fitted with 900 hemispherical inline baffles. The computations are based on realizable k-ɛ model with standard wall function considering the finite volume method, and the SIMPLE algorithm has been implemented. Computational Study are carried out for Reynolds number, Re ranging from 80000 to 120000, Prandtl Number, Pr of 0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of the channel, hydrodynamic entry length, thermal entry length and the test section. Ansys Fluent 15.0 software has been used to solve the flow field. Study reveals that circular pipe having baffles has a higher Nusselt number and friction factor compared to the smooth circular pipe without baffles. Maximum Nusselt number and friction factor are obtained for the PR=5 and PR=1 respectively. Nusselt number increases while pitch ratio increases in the range of study; however, friction factor also decreases up to PR 3 and after which it becomes almost constant up to PR 5. Thermal enhancement factor increases with increasing pitch ratio but with slightly decreasing Reynolds number in the range of study and becomes almost constant at higher Reynolds number. The computational results reveal that optimum thermal enhancement factor of 900 inline hemispherical baffle is about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows that the optimum pitch ratio for which the baffles can be installed in such very high turbulent flows should be 5. Results show that pitch ratio and Reynolds number play an important role on both fluid flow and heat transfer characteristics.

Keywords: friction factor, heat transfer, turbulent flow, circular duct, baffle, pitch ratio

Procedia PDF Downloads 357

Authors: Aka S. Koffi, N’Goran Yao, Philippe Bastide, Denis Bruneau, Diby Kadjo

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Cocoa beans (Theobroma cocoa L.) are the main components for chocolate manufacturing. The beans must be correctly fermented at first. Traditional process to perform the first fermentation (lactic fermentation) often consists in confining cacao beans using banana leaves or a fermentation basket, both of them leading to a poor product thermal insulation and to an inability to mix the product. Box fermenter reduces this loss by using a wood with large thickness (e>3cm), but mixing to homogenize the product is still hard to perform. Automatic fermenters are not rentable for most of producers. Heat (T>45°C) and acidity produced during the fermentation by microbiology activity of yeasts and bacteria are enabling the emergence of potential flavor and taste of future chocolate. In this study, a cylindro-rotative fermenter (FCR-V1) has been built and coconut fibers were used in its structure to confine heat. An axis of rotation (360°) has been integrated to facilitate the turning and homogenization of beans in the fermenter. This axis permits to put fermenter in a vertical position during the anaerobic alcoholic phase of fermentation, and horizontally during acetic phase to take advantage of the mid height filling. For circulation of air flow during turning in acetic phase, two woven rattan with grid have been made, one for the top and second for the bottom of the fermenter. In order to reduce air flow during acetic phase, two airtight covers are put on each grid cover. The efficiency of the turning by this kind of rotation, coupled with homogenization of the temperature, caused by the horizontal position in the acetic phase of the fermenter, contribute to having a good proportion of well-fermented beans (83.23%). In addition, beans’pH values ranged between 4.5 and 5.5. These values are ideal for enzymatic activity in the production of the aromatic compounds inside beans. The regularity of mass loss during all fermentation makes it possible to predict the drying surface corresponding to the amount being fermented.

Keywords: cocoa fermentation, fermenter, microbial activity, temperature, turning

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Authors: Zayneb Kthiri, Walid Hamada

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The application of organic fertilizers is generally known to be useful to sustain soil fertility and plant growth, especially in poor soils, with less than 1% of organic matter, as it is very common in our Tunisian fields. Therefore, we focused on evaluating the effect of a new released liquid organic fertilizer named Solorga (with 5% of organic matter) compared to a reference product (Espartan: Kimitec, Spain) on tomato plant growth and physiology. Both fertilizers, derived from plant decomposition, were applied at an early stage in hydroponic system and under greenhouse. In hydroponic system, after 14 days of their application by root feeding, a significant difference was observed between treatments. Indeed, Solorga improved shoots and roots length, as well as the biomass respectively, by 45%, 27%, and 27.8% increase rate, while compared to control plants. However, Espartan induced less the measured parameters while compared to untreated control. Moreover, Solorga significantly increased the chlorophyll content by 42% compared to control and by 32% compared to Espartan. In the greenhouse, after 20 days of treatments, the results showed a significant effect of both fertilizers on SPAD index and the number of flowers blossom. Solorga increased the amount of chlorophyll present in the leaf by 7% compared to Espartan as well as the plant height under greenhouse. Moreover, the number of flowers blossom increased by 15% in plants treated with Solorga while compared to Espartan. Whereas, there is no notable difference between both organic fertilizers on the fruits blossom and the number of fruits per blossom. In conclusion, even though there is a difference in the organic matter between both fertilizers, Solorga improved better the plant growth in controlled conditions in hydroponic system while compared to Espartan. Altogether the obtained results are encouraging for the use of Solorga as a soil enriching source of organic matter to help plants to boost their growth and help them to overcome abiotic stresses linked to soil fertility.

Keywords: tomato, plant growth, organic fertilizer, hydroponic system, greenhouse

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Authors: Foteini Zagklavara, Peter Jimack, Nikil Kapur, Ozz Querin, Harvey Thompson

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The invention and development of the Polymerase Chain Reaction (PCR) technology have revolutionised molecular biology and molecular diagnostics. There is an urgent need to optimise their performance of those devices while reducing the total construction and operation costs. The present study proposes a CFD-enabled optimisation methodology for continuous flow (CF) PCR devices with serpentine-channel structure, which enables the trade-offs between competing objectives of DNA amplification efficiency and pressure drop to be explored. This is achieved by using a surrogate-enabled optimisation approach accounting for the geometrical features of a CF μPCR device by performing a series of simulations at a relatively small number of Design of Experiments (DoE) points, with the use of COMSOL Multiphysics 5.4. The values of the objectives are extracted from the CFD solutions, and response surfaces created using the polyharmonic splines and neural networks. After creating the respective response surfaces, genetic algorithm, and a multi-level coordinate search optimisation function are used to locate the optimum design parameters. Both optimisation methods produced similar results for both the neural network and the polyharmonic spline response surfaces. The results indicate that there is the possibility of improving the DNA efficiency by ∼2% in one PCR cycle when doubling the width of the microchannel to 400 μm while maintaining the height at the value of the original design (50μm). Moreover, the increase in the width of the serpentine microchannel is combined with a decrease in its total length in order to obtain the same residence times in all the simulations, resulting in a smaller total substrate volume (32.94% decrease). A multi-objective optimisation is also performed with the use of a Pareto Front plot. Such knowledge will enable designers to maximise the amount of DNA amplified or to minimise the time taken throughout thermal cycling in such devices.

Keywords: PCR, optimisation, microfluidics, COMSOL

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Authors: Mohamed Aboelghar, Ayman Abou Hadid, Usama Albehairy, Asmaa Khater

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Sustainable agricultural development of the desert areas of Egypt under the pressure of irrigation water scarcity is a significant national challenge. Existing water harvesting techniques on the northwest coast of Egypt do not ensure the optimal use of rainfall for agricultural purposes. Basin-scale hydrology potentialities were studied to investigate how available annual rainfall could be used to increase agricultural production. All data related to agricultural production included in the form of geospatial layers. Thematic classification of Sentinal-2 imagery was carried out to produce the land cover and crop maps following the (FAO) system of land cover classification. Contour lines and spot height points were used to create a digital elevation model (DEM). Then, DEM was used to delineate basins, sub-basins, and water outlet points using the Soil and Water Assessment Tool (Arc SWAT). Main soil units of the study area identified from Land Master Plan maps. Climatic data collected from existing official sources. The amount of precipitation, surface water runoff, potential, and actual evapotranspiration for the years (2004 to 2017) shown as results of (Arc SWAT). The land cover map showed that the two tree crops (olive and fig) cover 195.8 km2 when herbaceous crops (barley and wheat) cover 154 km2. The maximum elevation was 250 meters above sea level when the lowest one was 3 meters below sea level. The study area receives a massive variable amount of precipitation; however, water harvesting methods are inappropriate to store water for purposes.

Keywords: water catchements, remote sensing, GIS, sustainable agricultural development

Procedia PDF Downloads 97

Authors: Ülle Parm, Kata Pedamäe, Jaak Jürimäe, Evelin Lätt, Aivar Orav, Anna-Liisa Tamm

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Vegetarianism has gained popularity across the world. It`s being chosen for multiple reasons, but among Estonians, these have remained unknown. Previously, attention to bone health and probable nutrient deficiency of vegetarians has been paid and in vegetarians lower body mass index (BMI) and blood cholesterol level has been found but the results are inconclusive. The goal was to explain reasons for choosing vegetarian diet in Estonia and impact of vegetarianism to body composition – BMI, fat percentage (fat%), fat mass (FM), and fat free mass (FFM). The study group comprised of 68 vegetarians and 103 omnivorous. The determining body composition with DXA (Hologic) was concluded in 2013. Body mass (medical electronic scale, A&D Instruments, Abingdon, UK) and height (Martin metal anthropometer to the nearest 0.1 cm) were measured and BMI calculated (kg/m2). General data (physical activity level included) was collected with questionnaires. The main reasons why vegetarianism was chosen were the healthiness of the vegetarian diet (59%) and the wish to fight for animal rights (72%) Food additives were consumed by less than half of vegetarians, more often by men. Vegetarians had lower BMI than omnivores, especially amongst men. Based on BMI classification, vegetarians were less obese than omnivores. However, there were no differences in the FM, FFM and fat percentage figures of the two groups. Higher BMI might be the cause of higher physical activity level among omnivores compared with vegetarians. For classifying people as underweight, normal weight, overweight and obese both BMI and fat% criteria were used. By BMI classification in comparison with fat%, more people in the normal weight group were considered; by using fat% in comparison with BMI classification, however, more people categorized as overweight. It can be concluded that the main reasons for vegetarianism chosen in Estonia are healthiness of the vegetarian diet and the wish to fight for animal rights and vegetarian diet has no effect on body fat percentage, FM and FFM.

Keywords: body composition, body fat percentage, body mass index, vegetarianism

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Authors: G. Nampa, M. Ndlovu

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Mutualistic relationships amongst organisms drive diversity in terrestrial ecosystems. Yet, few mutual associations have been documented in the semi-arid savannas of Africa. The levels and benefits of association between Carissa bispinosa, a medium-sized evergreen thorny shrub, and Trinervitermes trinervoides, an ecosystem engineer termite species, were studied at a semi-arid savanna setting in Nylsvley nature reserve, South Africa. It was hypothesized that there would be a close plant-insect association since termite mounds provide nutrients for plant growth and, in return, the thorny shrubs protect mounds from predation and also provide a temperature buffer. Comparative plant and mounds measurements were taken from associated and isolated occurrences seasonally. Soil particle size, macro- and micronutrients were also evaluated from mounds and the adjacent topsoil matrix General Additive Mixed Models were used to assess internal mound temperatures in relation to prevailing ambient and plant shade temperatures. Findings revealed that plants growing on mounds were significantly taller with a wider canopy and remained greener in the dry season with more fruits. On the other hand, termite mounds under plants were less prone to be damaged by aardvarks and pangolins and had a significantly wider diameter than exposed mounds. All soil macronutrients except for calcium and phosphorous were enriched in mounds relative to the matrix. Only Manganese was enriched in mounds while the other micronutrients (Cu, Fe, Zn and B) were not. Termite mounds under plants maintained a better constant and higher mean internal temperature during winter compared to exposed mounds. To our best knowledge, the study has revealed a previously undocumented survival mechanism that termites use to escape extreme temperatures and predation in semi-arid savannas.

Keywords: mound, mutualism, soil nutrients, termites, thermoregulation

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Authors: Rym Saidi, Pape Alioune Ndiaye, Ibnyasser Ammar, Zineb Rchiad, Khalid Daoui, Issam Kadmiri Meftahi, Adnane Bargaz

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Chickpea (Cicer arietinum L.) is an important leguminous crop grown worldwide and plays a significant role in humans’ dietary consumption. Alongside nitrogen (N), low phosphorus (P) availability within agricultural soils is one of the major factors limiting chickpea growth and productivity. The combined application of beneficial bacterial inoculants and Rock P-fertilizer could boost chickpea performance and productivity, increasing P-utilization efficiency and minimizing nutrient losses under P-deficiency conditions. A greenhouse experiment was conducted to evaluate the response of chickpeas to two P-fertilizer forms (RP and TSP) under N2-fixer and P-solubilizer consortium inoculation to improve biological N fixation and P nutrition under P-deficient conditions. Under inoculation, chickpea chlorophyll content and chlorophyll fluorescence (RP+I and TSP+I) were increased compared to uninoculated treatments. The RP+I treatment increased both shoot and root dry weights by 48,80% and 72,68%, respectively, compared to the uninoculated RP fertilized control. Indeed, the bacterial consortium contributed to enhancing root morphological traits (e.g., root volume, surface area, and diameter) of all inoculated treatments versus the uninoculated treatments. Furthermore, soil available P and root inorganic P were significantly improved in RP+I by 162,84% and 73,24%, respectively, compared to uninoculated RP control. Our research outcomes suggest that the co-inoculation of chickpeas with N2-fixing, and P-solubilizing bacteria improves biomass yield and nutrient uptake. Eventually, enhancing chickpea agrophysiological performance, especially in restricted P-availability conditions.

Keywords: chickpea, consortium, beneficial bacterial inoculants, phosphorus deficiency, rock p-fertilizer, nutrient uptake

Procedia PDF Downloads 41

Authors: H. Ju, M. Jones, G. D. Mishra

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Introduction: Limited longitudinal studies have examined the relationship between BMI and dysmenorrhea, resulting in mixed results. This study aims to investigate the long-term association between BMI and dysmenorrhea. Methods: 9,688 women from Australian Longitudinal Study on Women’s Health (ALSWH), a prospective population-based cohort study, were followed for 13 years. Data were collected through self-reported questionnaires repeatedly on all variables, including dysmenorrhea, weight and height. The longitudinal association between dysmenorrhea and BMI or BMI transition (change of BMI categories between two successive surveys) was investigated by generalized estimating equations. Results: When the women were aged 22 to 27 years, approximately 11% were obese, 7% underweight, and 25% reported dysmenorrhea. Over the study period, the prevalence of obesity doubled whereas that of underweight declined substantially. The prevalence of dysmenorrhea remained relatively stable. Compared to women with a normal weight, significantly higher odds of reporting dysmenorrhea were detected for both women who were underweight (odds ratio (OR) 1.25, 95% confidence interval (CI) 1.09, 1.43) and obese (OR 1.20, 95% CI 1.10, 1.31). Being overweight was not associated with increased risk of dysmenorrhea. Compared to women who remained at normal weight or overweight over time, significant risk was detected for women who: remained underweight or obese (OR 1.35, 95% CI 1.23, 1.49), were underweight but became normal or overweight (OR 1.29, 95% CI 1.11, 1.50), became underweight (OR 1.24, 95% CI 1.01, 1.52). However, the higher risk among obese women disappeared when they lost weight and became normal weight or overweight (OR 1.07, 95% CI 0.87, 1.30). Conclusions: A U-shaped association was revealed between dysmenorrhea and BMI, revealing higher risk of dysmenorrhea for both underweight and obese women. Further, the risk disappeared when obese women lost weight and acquired a healthier BMI. However obesity certainly poses a greater burden of disease from the public health perspective, thus requires greater effort to tackle the increasing problem at the population level. It is important to maintain a healthy weight over time for women to enjoy a better reproductive health.

Keywords: body mass index, dysmenorrhea, obesity, painful period, underweight

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Authors: Paolo Boscaro, Vasile Hulea, François Fajula, Francis Luck, Anne Galarneau

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TiO2 based monoliths with hierarchical macropores and mesopores have been synthesized following a novel one pot sol-gel synthesis method. Taking advantage of spinodal separation that occurs between titanium isopropoxide and an acidic solution in presence of polyethylene oxide polymer, monoliths with homogeneous interconnected macropres of 3 μm in diameter and mesopores of ca. 6 nm (surface area 150 m2/g) are obtained. Furthermore, these monoliths present some carbon and nitrogen (as shown by XPS and elemental analysis), which considerably reduce titanium oxide energy gap and enable light to be absorbed up to 700 nm wavelength. XRD shows that anatase is the dominant phase with a small amount of brookite. Enhanced light absorption and high porosity of the monoliths are responsible for a remarkable photocatalytic activity. Wastewater treatment has been performed in closed reactor under sunlight using orange G dye as target molecule. Glass reactors guarantee that most of UV radiations (to almost 300 nm) of solar spectrum are excluded. TiO2 nanoparticles P25 (usually used in photocatalysis under UV) and un-doped TiO2 monoliths with similar porosity were used as comparison. C,N-doped TiO2 monolith allowed a complete colorant degradation in less than 1 hour, whereas 10 h are necessary for 40% colorant degradation with P25 and un-doped monolith. Experiment performed in the dark shows that only 3% of molecules have been adsorbed in the C,N-doped TiO2 monolith within 1 hour. The much higher efficiency of C,N-doped TiO2 monolith in comparison to P25 and un-doped monolith, proves that doping TiO2 is an essential issue and that nitrogen and carbon are effective dopants. Monoliths offer multiples advantages in respect to nanometric powders: sample can be easily removed from batch (no needs to filter or to centrifuge). Moreover flow reactions can be set up with cylindrical or flat monoliths by simple sheathing or by locking them with O-rings.

Keywords: C-N doped, sunlight photocatalytic activity, TiO2 monolith, visible absorbance

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Authors: Nahia H. Sassine, Frédéric-Victor Donzé, Arnaud Bruch, Barthélemy Harthong

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Thermal Energy Storage (TES) systems are central elements of various types of power plants operated using renewable energy sources. Packed bed TES can be considered as a cost–effective solution in concentrated solar power plants (CSP). Such a device is made up of a tank filled with a granular bed through which heat-transfer fluid circulates. However, in such devices, the tank might be subjected to catastrophic failure induced by a mechanical phenomenon known as thermal ratcheting. Thermal stresses are accumulated during cycles of loading and unloading until the failure happens. For instance, when rocks are used as storage material, the tank wall expands more than the solid medium during charge process, a gap is created between the rocks and tank walls and the filler material settles down to fill it. During discharge, the tank contracts against the bed, resulting in thermal stresses that may exceed the wall tank yield stress and generate plastic deformation. This phenomenon is repeated over the cycles and the tank will be slowly ratcheted outward until it fails. This paper aims at studying the evolution of tank wall stresses over granular bed thermal cycles, taking into account both thermal and mechanical loads, with a numerical model based on the discrete element method (DEM). Simulations were performed to study two different thermal configurations: (i) the tank is heated homogeneously along its height or (ii) with a vertical gradient of temperature. Then, the resulting loading stresses applied on the tank are compared as well the response of the internal granular material. Besides the study of the influence of different thermal configurations on the storage tank response, other parameters are varied, such as the internal angle of friction of the granular material, the dispersion of particles diameters as well as the tank’s dimensions. Then, their influences on the kinematics of the granular bed submitted to thermal cycles are highlighted.

Keywords: discrete element method (DEM), thermal cycles, thermal energy storage, thermocline

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Authors: Meera A. Albloushi, Adel B. Gougam

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The development in the field of piezoelectrics has led to a renewed interest in ZnO nanowires (NWs) as a promising material in the nanogenerator devices category. It can be used as a power source for self-powered electronic systems with higher density, higher efficiency, longer lifetime, as well as lower cost of fabrication. Highly aligned ZnO nanowires seem to exhibit a higher performance compared with nonaligned ones. The purpose of this study was to develop ZnO nanowires and to investigate their electrical and chemical properties for various applications. They were grown on silicon (100) and glass substrates. We have used a low temperature and non-hazardous method: aqueous chemical growth (ACG). ZnO (non-doped) and AZO (Aluminum doped) seed layers were deposited using RF magnetron sputteringunder Argon pressure of 3 mTorr and deposition power of 180 W, the times of growth were selected to obtain thicknesses in the range of 30 to 125 nm. Some of the films were subsequently annealed. The substrates were immersed tilted in an equimolar solution composed of zinc nitrate and hexamine (HMTA) of 0.02 M and 0.05 M in the temperature range of 80 to 90 ᵒC for 1.5 to 2 hours. The X-ray diffractometer shows strong peaks at 2Ө = 34.2ᵒ of ZnO films which indicates that the films have a preferred c-axis wurtzite hexagonal (002) orientation. The surface morphology of the films is investigated by atomic force microscope (AFM) which proved the uniformity of the film since the roughness is within 5 nm range. The scanning electron microscopes(SEM) (Quanta FEG 250, Quanta 3D FEG, Nova NanoSEM 650) are used to characterize both ZnO film and NWs. SEM images show forest of ZnO NWs grown vertically and have a range of length up to 2000 nm and diameter of 20-300 nm. The SEM images prove that the role of the seed layer is to enhance the vertical alignment of ZnO NWs at the pH solution of 5-6. Also electrical and optical properties of the NWs are carried out using Electrical Force Microscopy (EFM). After growing the ZnO NWs, developing the nano-generator is the second step of this study in order to determine the energy conversion efficiency and the power output.

Keywords: ZnO nanowires(NWs), aqueous chemical growth (ACG), piezoelectric NWs, harvesting enery

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