Search results for: coupled double quantum well (CDQW)

Authors: A. W. J. Wong, I. H. Ibrahim

Abstract:

Increasing urbanisation has driven building designers to incorporate natural ventilation in the designs of sustainable buildings. This project utilises Computational Fluid Dynamics (CFD) to investigate the natural ventilation of an academic building, SIT@SP, using an assessment criterion based on daily mean temperature and mean velocity. The areas of interest are the pedestrian level of first and fourth levels of the building. A reference case recommended by the Architectural Institute of Japan was used to validate the simulation model. The validated simulation model was then used for coupled simulations on SIT@SP and neighbouring geometries, under two wind speeds. Both steady and transient simulations were used to identify differences in results. Steady and transient results are agreeable with the transient simulation identifying peak velocities during flow development. Under a lower wind speed, the first level was sufficiently ventilated while the fourth level was not. The first level has excessive wind velocities in the higher wind speed and the fourth level was adequately ventilated. Fourth level flow velocity was consistently lower than those of the first level. This is attributed to either simulation model error or poor building design. SIT@SP is concluded to have a sufficiently ventilated first level and insufficiently ventilated fourth level. Future works for this project extend to modifying the urban geometry, simulation model improvements, evaluation using other assessment metrics and extending the area of interest to the entire building.

Keywords: buildings, CFD Simulations, natural ventilation, urban airflow

Procedia PDF Downloads 212

Authors: Ayoub Moufid, Najib Bennis, Soumia El Hani

Abstract:

The objective of greenhouse climate control is to improve the culture development and to minimize the production costs. A greenhouse is an open system to external environment and the challenge is to regulate the internal climate despite the strong meteorological disturbances. The internal state of greenhouse considered in this work is defined by too relevant and coupled variables, namely inside temperature and hygrometry. These two variables are chosen to describe the internal state of greenhouses due to their importance in the development of plants and their sensitivity to external climatic conditions, sources of weather disturbances. A multivariable model is proposed and validated by considering a greenhouse as black-box system and the least square method is applied to parameters identification basing on collected experimental measures. To regulate the internal climate, we propose a Model Predictive Control (MPC) scheme. This one considers the measured meteorological disturbances and the physical and operational constraints on the control and state variables. A successful feasibility study of the proposed controller is presented, and simulation results show good performances despite the high interaction between internal and external variables and the strong external meteorological disturbances. The inside temperature and hygrometry are tracking nearly the desired trajectories. A comparison study with an On/Off control applied to the same greenhouse confirms the efficiency of the MPC approach to inside climate control.

Keywords: climate control, constraints, identification, greenhouse, model predictive control, optimization

Procedia PDF Downloads 199

Authors: Daniel Micallef, Damien Bounaudet, Robert N. Farrugia, Simon P. Borg, Vincent Buhagiar, Tonio Sant

Abstract:

The physical effects of upstream flow obstructions such as vegetation on cross-ventilation phenomena of a building are important for issues such as indoor thermal comfort. Modelling such effects in Computational Fluid Dynamics simulations may also be challenging. The aim of this work is to establish the cross-ventilation jet behaviour in such complex terrain conditions as well as to provide guidelines on the implementation of CFD numerical simulations in order to model complex terrain features such as vegetation in an efficient manner. The methodology consists of onsite measurements on a test cell coupled with numerical simulations. It was found that the cross-ventilation flow is highly turbulent despite the very low velocities encountered internally within the test cells. While no direct measurement of the jet direction was made, the measurements indicate that flow tends to be reversed from the leeward to the windward side. Modelling such a phenomenon proves challenging and is strongly influenced by how vegetation is modelled. A solid vegetation tends to predict better the direction and magnitude of the flow than a porous vegetation approach. A simplified terrain model was also shown to provide good comparisons with observation. The findings have important implications on the study of cross-ventilation in complex terrain conditions since the flow direction does not remain trivial, as with the traditional isolated building case.

Keywords: complex terrain, cross-ventilation, wind driven ventilation, wind resource, computational fluid dynamics, CFD

Procedia PDF Downloads 388

Authors: Maisarah Jaafar, Neil I. Ward

Abstract:

Volcanic and geothermal activity can result in the release of arsenic (As), manganese (Mn), iron, selenium (Se), molybdenum (Mo) and uranium (U) into natural waters. Several studies have reported high levels of these elements in surface and groundwater in Argentina. The main focus has been on As associated with volcanic ash deposits. This study reports the trace element levels of groundwater from an agricultural region of south-eastern La Pampa and southern Buenos Aires provinces, Argentina which have reported high levels of human health problems (bone/teeth disorders, depression, arthritis, etc). Fifty-eight groundwater samples were collected from wells adjacent to Ruta 35 and an Agilent 7700x inductively coupled plasma mass spectrometer (ICP-MS) were used for total elemental analysis. Physicochemical analysis confirmed pH range of 7.05-8.84 and variable conductivity (988-3880 µS/cm) with total dissolved solid content of 502-1989 mg/l. The majority water samples are in an oxidizing environment (Eh= 45-146 mV). Total As levels ranged from (µg/l): 13.08 – 319.4 for La Pampa (LP) and 39.6 – 189.4 for Buenos Aires (BA); all above the WHO Guideline for Drinking Water, 10 µg/l As. Interestingly, Mo (LP: 1.85 – 85.39 µg/l; BA: 4.61– 55.55 µg/l;), Se (LP: 1.2 – 16.59 µg/l; BA: 0.3– 6.94 µg/l;) and U (LP: 1.85 – 85.39 µg/l; BA: 4.61– 55.55 µg/l;) levels are lower than reported values for northern La Pampa. Inter-elemental correlation displayed positive statistically significant between As-Mo, A-Se, As-U while negative statistically significant between As-Mn and As-Fe. This confirms that the source of the trace element is similar to that reported for other region of Argentina, namely volcanic ash deposition.

Keywords: Argentina, groundwater, trace element, volcanic activity

Procedia PDF Downloads 326

Authors: Batoul Mohamed Abdullatif, Nouf Ali Asiri

Abstract:

O. basilicum plant was subjected to deficit irrigation using four treatments viz. control, irrigated with 70% of soil water capacity (SWC), Treatment 1, irrigated with 50% SWC, Treatment 2, irrigated with 30% SWC and Treatment 3, irrigated with 10 % SWC. Photosynthesis pigments viz. chlorophyll a, b, and the carotenoids, proline accumulation, and oil quantity were investigated under these irrigation treatments. The results indicate that photosynthesis pigments and oil content of deficit irrigation treatments did not significantly reduced than that of the full irrigation control. Photosynthesis pigments were affected by the stage of growth and not by irrigation treatments. They were high during flowering stage and low during seed formation stage for all treatments. The lowest irrigation plants (10 % SWC) achieved, during flowering stage, 0.72 mg\g\fresh weight of chlorophyll a, compared to 0.43 mg\g\fresh weight in control plant, 0.40 mg\g\fresh weight of chlorophyll b, compared to 0.19 mg\g\fresh weight in control plants and 0.29 mg\g\fresh weight of carotenoids, compared to 0.21 mg\g\fresh weight in control plants. It has been shown that reduced irrigation rates tend to enhance O. basilicum to have high oil quantity reaching a value of 63.37 % in a very low irrigation rate (10 % SWC) compared to 45.38 of control in seeds. Proline was shown to be accumulated in roots to almost double the amount in shoot during flowering stage in treatment 3. This accumulation seems to have a pronounce effect on O. basilicum acclimation to deficit irrigation.

Keywords: deficit irrigation, photosynthesis pigments, proline accumulation, oil quantity, sweet basil flowering formation, seed formation

Procedia PDF Downloads 412

Authors: Jia Zhang, Fengmei Yao, Yanjing Tan

Abstract:

The accurate estimation of crop yield is of great importance for the food security. In this study, a process-based mechanism model was modified to estimate yield of C4 crop by modifying the carbon metabolic pathway in the photosynthesis sub-module of the RS-P-YEC (Remote-Sensing-Photosynthesis-Yield estimation for Crops) model. The yield was calculated by multiplying net primary productivity (NPP) and the harvest index (HI) derived from the ratio of grain to stalk yield. The modified RS-P-YEC model was used to simulate maize yield in the Northeast China Plain during the period 2002-2011. The statistical data of maize yield from study area was used to validate the simulated results at county-level. The results showed that the Pearson correlation coefficient (R) was 0.827 (P < 0.01) between the simulated yield and the statistical data, and the root mean square error (RMSE) was 712 kg/ha with a relative error (RE) of 9.3%. From 2002-2011, the yield of maize planting zone in the Northeast China Plain was increasing with smaller coefficient of variation (CV). The spatial pattern of simulated maize yield was consistent with the actual distribution in the Northeast China Plain, with an increasing trend from the northeast to the southwest. Hence the results demonstrated that the modified process-based model coupled with remote sensing data was suitable for yield prediction of maize in the Northeast China Plain at the spatial scale.

Keywords: process-based model, C4 crop, maize yield, remote sensing, Northeast China Plain

Procedia PDF Downloads 362

Authors: Nasiru Medugu Idris

Abstract:

This research is aimed at assessing the vulnerability of climate change to rural communities (farmers, herdsmen and fishermen) in Nigeria with the view to study the underlying causes and degree of vulnerability to climate change and examine the conflict between farmers and herdsmen as a result of climate change. This research employed the use of quantitative and qualitative means of data gathering techniques as well as physical observations. Six states (Kebbi, Adamawa, Nasarawa, Osun, Ebonyi, and Akwa Ibom) have been selected on the ground that they are key food production areas in the country and are therefore essential to continual food security in the country. So also, they also double as fishing communities in order to aid the comprehensive study of all the effects on climate on farmers and fishermen alike. Community focus group discussions were carried out in the various states for an interactive session and also to have firsthand information on their level of awareness on climate change. Climate data from the Nigerian Meteorological Agency over the past decade were collected for the purpose of analyzing trends in climate. The study observed that the level of vulnerability of rural dwellers most especially farmers, herdsmen and fishermen to climate change is very high due to their socioeconomic, ethnic and historical perspective of their trend. The study, therefore, recommends that urgent step needs to be put in place to help control natural hazards and man-made disasters and serious measures are also needed in order to minimize severe societal, economic and political crises; some of which may either escalate to violent conflicts or could be avoided by efforts of conflict resolution and prevention by the initiation of a process of de-escalation. So this study has recommended the best-fit adaptive and mitigation measures to climate change vulnerability in rural communities of Nigeria.

Keywords: adaptation, farmers, fishermen, herdsmen

Procedia PDF Downloads 179

Authors: Idit Avrahami, Alex Schechter, Lev Zakhvatkin

Abstract:

This research focuses on developing a compact and light Hydrogen Generator (HG), coupled with fuel cells (FC) to provide a High-Energy-Density Power-Pack (HEDPP) solution, which is 10 times Li-Ion batteries. The HEDPP is designed for portable & off-grid power applications such as Drones, UAVs, stationary off-grid power sources, unmanned marine vehicles, and more. Hydrogen gas provided by this device is delivered in the safest way as a chemical powder at room temperature and ambient pressure is activated only when the power is on. Hydrogen generation is based on a stabilized chemical reaction of Sodium Borohydride (SBH) and water. The proposed solution enables a ‘No Storage’ Hydrogen-based Power Pack. Hydrogen is produced and consumed on-the-spot, during operation; therefore, there’s no need for high-pressure hydrogen tanks, which are large, heavy, and unsafe. In addition to its high energy density, ease of use, and safety, the presented power pack has a significant advantage of versatility and deployment in numerous applications and scales. This patented HG was demonstrated using several prototypes in our lab and was proved to be feasible and highly efficient for several applications. For example, in applications where water is available (such as marine vehicles, water and sewage infrastructure, and stationary applications), the Energy Density of the suggested power pack may reach 2700-3000 Wh/kg, which is again more than 10 times higher than conventional lithium-ion batteries. In other applications (e.g., UAV or small vehicles) the energy density may exceed 1000 Wh/kg.

Keywords: hydrogen energy, sodium borohydride, fixed-wing UAV, energy pack

Procedia PDF Downloads 76

Authors: Kahlil Fredrick Cui, Marissa Pastor

Abstract:

Earthquakes are complex phenomena, exhibiting complex correlations in space, time, and magnitude. Recently, the concept of complex networks has been used to shed light on the statistical and dynamical characteristics of regional seismicity. In this work, we study the relationships and interactions of seismic regions in Chile, Japan, and the Philippines through weighted and directed complex network analysis. Geographical areas are digitized into cells of fixed dimensions which in turn become the nodes of the network when an earthquake has occurred therein. Nodes are linked if a correlation exists between them as determined and measured by a correlation metric. The networks are found to be scale-free, exhibiting power-law behavior in the distributions of their different centrality measures: the in- and out-degree and the in- and out-strength. The evidence is also found of preferential interaction between seismically active regions through their degree-degree correlations suggesting that seismicity is dictated by the activity of a few active regions. The importance of a seismic region to the overall seismicity is measured using a generalized centrality metric taken to be an indicator of its activity or passivity. The spatial distribution of earthquake activity indicates the areas where strong earthquakes have occurred in the past while the passivity distribution points toward the likely locations an earthquake would occur whenever another one happens elsewhere. Finally, we propose a method that would project the location of the next possible earthquake using the generalized centralities coupled with correlations calculated between the latest earthquakes and a geographical point in the future.

Keywords: complex networks, correlations, earthquake, hazard assessment

Procedia PDF Downloads 200

Authors: Chao Yi, Cunyue Lu, Lingwei Quan

Abstract:

Piezoelectric linear motors have the characteristics of great electromagnetic compatibility, high positioning accuracy, compact structure and no deceleration mechanism, which make it promising to applicate in micro-miniature precision drive systems. However, most piezoelectric motors are employed by flexible clamping, which has insufficient rigidity and is difficult to use in rapid positioning. Another problem is that this clamping method seriously affects the vibration efficiency of the vibrating unit. In order to solve these problems, this paper proposes a piezoelectric stack linear motor based on double-end rigid clamping. First, a piezoelectric linear motor with a length of only 35.5 mm is designed. This motor is mainly composed of a motor stator, a driving foot, a ceramic friction strip, a linear guide, a pre-tightening mechanism and a base. This structure is much simpler and smaller than most similar motors, and it is easy to assemble as well as to realize precise control. In addition, the properties of piezoelectric stack are reviewed and in order to obtain the elliptic motion trajectory of the driving head, a driving scheme of the longitudinal-shear composite stack is innovatively proposed. Finally, impedance analysis and speed performance testing were performed on the piezoelectric linear motor prototype. The motor can measure speed up to 25.5 mm/s under the excitation of signal voltage of 120 V and frequency of 390 Hz. The result shows that the proposed piezoelectric stacked linear motor obtains great performance. It can run smoothly in a large speed range, which is suitable for various precision control in medical images, aerospace, precision machinery and many other fields.

Keywords: piezoelectric stack, linear motor, rigid clamping, elliptical trajectory

Procedia PDF Downloads 148

Authors: Kazeem Adesina Dauda, Waheed Babatunde Yahya

Abstract:

To design a tree that maximizes within-node homogeneity, there is a need for a homogeneity measure that is appropriate for event history data with multiple risks. We consider the use of Deviance and Modified Cox-Snell residuals as a measure of impurity in Classification Regression Tree (CART) and compare our results with the results of Fiona (2008) in which homogeneity measures were based on Martingale Residual. Data structure approach was used to validate the performance of our proposed techniques via simulation and real life data. The results of univariate competing risk revealed that: using Deviance and Cox-Snell residuals as a response in within node homogeneity classification tree perform better than using other residuals irrespective of performance techniques. Bone marrow transplant data and double-blinded randomized clinical trial, conducted in other to compare two treatments for patients with prostate cancer were used to demonstrate the efficiency of our proposed method vis-à-vis the existing ones. Results from empirical studies of the bone marrow transplant data showed that the proposed model with Cox-Snell residual (Deviance=16.6498) performs better than both the Martingale residual (deviance=160.3592) and Deviance residual (Deviance=556.8822) in both event of interest and competing risks. Additionally, results from prostate cancer also reveal the performance of proposed model over the existing one in both causes, interestingly, Cox-Snell residual (MSE=0.01783563) outfit both the Martingale residual (MSE=0.1853148) and Deviance residual (MSE=0.8043366). Moreover, these results validate those obtained from the Monte-Carlo studies.

Keywords: within-node homogeneity, Martingale residual, modified Cox-Snell residual, classification and regression tree

Procedia PDF Downloads 262

Authors: Y. L. Hor, H. S. Chu, V. P. Bui

Abstract:

Composite material is widely used to replace conventional material, especially in the aerospace industry to reduce the weight of the devices. It is formed by combining reinforced materials together via adhesive bonding to produce a bulk material with alternated macroscopic properties. In bulk composites, degradation may occur in microscopic scale, which is in each individual reinforced fiber layer or especially in its matrix layer such as delamination, inclusion, disbond, void, cracks, and porosity. In this paper, we focus on the detection of defect in matrix layer which the adhesion between the composite plies is in contact but coupled through a weak bond. In fact, the adhesive defects are tested through various nondestructive methods. Among them, pulsed phase thermography (PPT) has shown some advantages providing improved sensitivity, large-area coverage, and high-speed testing. The aim of this work is to develop an efficient numerical model to study the application of PPT to the nondestructive inspection of weak bonding in composite material. The resulting thermal evolution field is comprised of internal reflections between the interfaces of defects and the specimen, and the important key-features of the defects presented in the material can be obtained from the investigation of the thermal evolution of the field distribution. Computational simulation of such inspections has allowed the improvement of the techniques to apply in various inspections, such as materials with high thermal conductivity and more complex structures.

Keywords: pulsed phase thermography, weak bond, composite, CFRP, computational modelling, optimization

Procedia PDF Downloads 159

Authors: Diana La Forgia, Jean Baptiste Thibord, François Verheggen

Abstract:

Volatiles Organic Compound (VOCs) are one of the many features of defense used by plants in their eternal fight against pests. Their main role is to attract the natural enemies of the herbivores. But on another hand, they can be used by the same herbivores to locate plants while foraging. In an attempt to fill a gap of knowledge in a complex web of interactions, we focused on wireworms (Coleoptera:Elateridae). Wireworms whose larvae feed on roots are one of the most spread pests of valuable crops such as maize and potatoes, causing important economical damage. Little is known about the root compounds that are playing a role in the attraction of the larvae. In order to know more about these compounds, we compared four different maize varieties (Zea mays mays) that are known to have different levels of attraction, from weak to strong, for wireworms in fields. We tested the attraction of larvae in laboratory conditions in dual-choice olfactometer assays where they were offered all possible combinations of the four maize varieties. Contemporary, we collected the VOCs of each variety during 24h using a push-and-pull system. The collected samples were then analyzed by gas chromatography coupled with a mass spectrometer (GC-MS) to identify their molecular profiles. The choice of the larvae was dependent on the offered combination and some varieties were preferred to others. Differences were also observed in terms of quantitative and qualitative emissions of volatile profiles between the maize varieties. Our aim is to develop traps based on VOCs from maize roots to open a new frontier in wireworms management.

Keywords: integrated pest management, maize roots, plant defense, volatile organic compounds, wireworms

Procedia PDF Downloads 149

Authors: Laura Lamas Abraira

Abstract:

Large-scale Chinese immigration in Spain emerged in the 80's. Engaged in their own businesses or working for other Chinese migrants with long schedules, young couples had to choose between contracting or transnationalising the care labour as they were unable to combine productive and reproductive tasks. In most cases, they decided to transnationalize the care labour embodied on grandparents or children migratory paths. Either the grandparents go to Spain to take care of their grandchildren or the kids were left behind or sent to China after being born in Spain in order to be raised with their extended family members. Very little is known about how the people who have been raised in a transnational context relates their own experience and agency as care managers within the family care cycle. In order to fill this gap, this paper aims to inquire into these transnationally-reared Chinese young adults’ narratives about their own experience and expectations (past, present and future) by adopting care circulation and care cycle approach within life course framework. Drawing upon a qualitative study resulting from a multi-sited ethnography (Spain-China), we argue that young adults raised in transnational context build their narratives as a result of an otherness process related to their parents and an essentialization of their Chinese roots to use selectively among different contexts. In doing so, these family narratives constitute a part of their social identity that interact with other dimensions such as the ethnic one. We suggest when building their parent's otherness they also build their sameness among pairs, as members of the same club, marked by transnational care on a double time basis: the practices of their parents as wrong past, and their own as an amendable future.

Keywords: Chinese families, narratives, transnational care, young adults

Procedia PDF Downloads 376

Authors: M. A. Abdel-Wahed, Nayera Elmorsi Hassan, Safaa Shafik Imam, Ola G. El-Farghali, Khadija M. Alian

Abstract:

Low-birth-weight is a challenging public health problem. Aim: to clarify role of zinc on enhancing catch-up growth of low-birth-weight and find out a proposed relationship between zinc effect on growth and the main growth hormone mediator, IGF-1. Methods: Study is a double-blind-randomized-placebo-controlled trial conducted on low-birth-weight-neonates delivered at Ain Shams University Maternity Hospital. It comprised 200 Low-birth-weight-neonates selected from those admitted to NICU. Neonates were randomly allocated into one of the following two groups: group I: low-birth-weight; AGA or SGA on oral zinc therapy at dose of 10 mg/day; group II: Low-birth-weight; AGA or SGA on placebo. Anthropometric measurements were taken including birth weight, length; head, waist, chest, mid-upper arm circumferences, triceps and sub-scapular skin-fold thicknesses. Results: At 12-month-old follow-up visit, mean weight, length; head (HC), waist, chest, mid-upper arm circumferences and triceps; also, infant’s proportions had values ≥ 10th percentile for weight, length and HC were significantly higher among infants of group I when compared to those of group II. Oral zinc therapy was associated with 24.88%, 25.98% and 19.6% higher proportion of values ≥ 10th percentile regarding weight, length and HC at 12-month-old visit, respectively [NNT = 4, 4 and 5, respectively]. Median IGF-1 levels measured at 6 months were significantly higher in group I compared to group II (median (range): 90 (19 – 130) ng/ml vs. 74 (21 – 130) ng/ml, respectively, p=0.023). Conclusion: Oral zinc therapy in low-birth-weight neonates was associated with significantly more catch-up growth at 12-months-old and significantly higher serum IGF-1 at 6-month-old.

Keywords: low-birth-weight, zinc, catch-up growth, neonates

Procedia PDF Downloads 407

Authors: Isabella Schwartz, Ori Safran, Naama Karniel, Michal Abel, Adina Berko, Martin Seyres, Tamir Tsoar, Sigal Portnoy

Abstract:

Virtual Reality allows to manipulate the patient’s perception, thereby providing a motivational addition to real-time biofeedback exercises. We aimed to test the effect of manipulated virtual kinematic intervention on measures of active and passive Range of Motion (ROM), pain, and disability level in individuals with traumatic stiff shoulder. In a double-blinded study, patients with stiff shoulder following proximal humerus fracture and non-operative treatment were randomly divided into a non-manipulated feedback group (NM-group; N=6) and a manipulated feedback group (M-group; N=7). The shoulder ROM, pain, and the Disabilities of the Arm, Shoulder and Hand (DASH) scores were tested at baseline and after the 6 sessions, during which the subjects performed shoulder flexion and abduction in front of a graphic visualization of the shoulder angle. The biofeedback provided to the NM-group was the actual shoulder angle and the feedback provided to the M-group was manipulated so that 10° were constantly subtracted from the actual angle detected by the motion capture system. The M-group showed greater improvement in the active flexion ROM, with median and interquartile range of 197.1 (140.5-425.0) compared to 142.5 (139.1-151.3) for the NM-group (p=.046). Also, the M-group showed greater improvement in the DASH scores, with median and interquartile range of 67.7 (52.8-86.2) compared to 89.7 (83.8-98.3) for the NM-group (p=.022). Manipulated intervention is beneficial in individuals with traumatic stiff shoulder and should be further tested for other populations with orthopedic injuries.

Keywords: virtual reality, biofeedback, shoulder pain, range of motion

Procedia PDF Downloads 116

Authors: Marwa T. Badawy, Alaa F. Bakr, Nesrine Hegazi, Mohamed A. Farag, Ahmed Abdellatif

Abstract:

Diabetes Mellitus (DM) is a chronic disease affecting a large population worldwide. Africa is rich in native medicinal plants with myriad health benefits, though less explored towards the development of specific drug therapy as in diabetes. This study aims to determine the in vivo antidiabetic potential of the well-reported and traditionally used fruits of Baobab (Adansonia digitata L.) using STZ induced diabetic model. The in-vitro cytotoxic and antioxidant properties were examined using MTT assay on L-929 fibroblast cells and DPPH antioxidant assays, respectively. The extract showed minimal cytotoxicity with an IC50 value of 105.7 µg/mL. Histopathological and immunohistochemical investigations showed the hepatoprotective and the renoprotective effects of A. digitata fruits’ extract, implying its protective effects against diabetes complications. These findings were further supported by biochemical assays, which showed that i.p., injection of a low dose (150 mg/kg) of A. digitata twice a week lowered the fasting blood glucose levels, lipid profile, hepatic and renal markers. For a comprehensive overview of extract metabolites composition, ultrahigh performance (UHPLC) analysis coupled to high-resolution tandem mass spectrometry (HRMS/MS) in synchronization with molecular networks led to the annotation of 77 metabolites, among which 50% are reported for the first time in A. digitata fruits.

Keywords: adansonia digital, diabetes mellitus, metabolomics, streptozotocin, Sprague, dawley rats

Procedia PDF Downloads 154

Authors: Riccardo Pasquali, Keith Harlin, Mark Muller

Abstract:

The ShallowTherm project is focussed on developing and applying a methodology for extrapolating relatively sparsely sampled thermal conductivity measurements across Ireland using mapped Litho-Electrical (LE) units. The primary data used consist of electrical resistivities derived from the Geological Survey Ireland Tellus airborne electromagnetic dataset, GIS-based maps of Irish geology, and rock thermal conductivities derived from both the current Irish Ground Thermal Properties (IGTP) database and a new programme of sampling and laboratory measurement. The workflow has been developed across three case-study areas that sample a range of different calcareous, arenaceous, argillaceous, and volcanic lithologies. Statistical analysis of resistivity data from individual geological formations has been assessed and integrated with detailed lithological descriptions to define distinct LE units. Thermal conductivity measurements from core and hand samples have been acquired for every geological formation within each study area. The variability and consistency of thermal conductivity measurements within each LE unit is examined with the aim of defining a characteristic thermal conductivity (or range of thermal conductivities) for each LE unit. Mapping of LE units, coupled with characteristic thermal conductivities, provides a method of defining thermal conductivity properties at a regional scale and facilitating the design of ground source heat pump closed-loop collectors.

Keywords: thermal conductivity, ground source heat pumps, resistivity, heat exchange, shallow geothermal, Ireland

Procedia PDF Downloads 171

Authors: Omar Dib, Rita Yaacoub, Luc Eveleigh, Nathalie Locquet, Hussein Dib, Ali Bassal, Christophe B. Y. Cordella

Abstract:

The potential of front-face fluorescence coupled with chemometric techniques, namely parallel factor analysis (PARAFAC) and multiple linear regression (MLR) as a rapid analysis tool to characterize Lebanese virgin olive oils was investigated. Fluorescence fingerprints were acquired directly on 102 Lebanese virgin olive oil samples in the range of 280-540 nm in excitation and 280-700 nm in emission. A PARAFAC model with seven components was considered optimal with a residual of 99.64% and core consistency value of 78.65. The model revealed seven main fluorescence profiles in olive oil and was mainly associated with tocopherols, polyphenols, chlorophyllic compounds and oxidation/hydrolysis products. 23 MLR regression models based on PARAFAC scores were generated, the majority of which showed a good correlation coefficient (R > 0.7 for 12 predicted variables), thus satisfactory prediction performances. Acid values, peroxide values, and Delta K had the models with the highest predictions, with R values of 0.89, 0.84 and 0.81 respectively. Among fatty acids, linoleic and oleic acids were also highly predicted with R values of 0.8 and 0.76, respectively. Factors contributing to the model's construction were related to common fluorophores found in olive oil, mainly chlorophyll, polyphenols, and oxidation products. This study demonstrates the interest of front-face fluorescence as a promising tool for quality control of Lebanese virgin olive oils.

Keywords: front-face fluorescence, Lebanese virgin olive oils, multiple Linear regressions, PARAFAC analysis

Procedia PDF Downloads 444

Authors: Jinee Gogoi, Som K. Sharma, Kalyan Bhuyan

Abstract:

The atmospheric layers are coupled to each other with the different dynamical, electrical, radiative and chemical processes. A large scale thermodynamical phenomenon in winter polar regions which affects the middle atmosphere vigorously is Sudden Stratospheric Warming (SSW). Two major SSW events were occurred during 1998-1999; one in December 1998 which is associated with vortex displacement and another in February- March 1999 associated with vortex splitting. Lidar study of these two major events from Mt. Abu (24.36⁰N, 72.45⁰E, ~1670 m amsl) has shown that though SSWs are mostly observed over high and mid latitudes, their effects can also be seen over India. We have studied ionospheric variations (primarily fₒF₂, h’F and hpF₂) over Ahmedabad (23.1⁰N, 72.58⁰E) during these events. Ionospheric disturbances have been found after four-five days of peak temperature. An increase (decrease) in critical frequency (fₒF₂) during morning (afternoon) has been noticed which may be in response to the updrift (down drift). Effects are stronger during displacement event (1998) than during the splitting event (1999). We have also studied some recent events occurred during 2006 (January), 2009 (January) and 2013 (January) using temperature data from Sounding of Atmosphere using Broadband Emission Radiometry (SABER) satellite. Though some modeling work supports the hypothesis that planetary waves are responsible for atmosphere-ionosphere coupling, there is still more significant works to do to understand how exactly the coupling can take place.

Keywords: sudden stratospheric warming (SSW), polar vortex, ionosphere, critical frequency

Procedia PDF Downloads 241

Authors: Mehrdad Gholami, Shima Behkami, Sharifuddin B. Md. Zain, Firdaus A. B. Kamaruddin

Abstract:

Starting from the first application of a microwave oven for sample preparation in 1975 for the purpose of wet ashing of biological samples using a domestic microwave oven, many microwave-assisted dissolution vessels have been developed. The advanced vessels are armed with special safety valve that release the excess of pressure while the vessels are in critical conditions due to applying high power of microwave. Nevertheless, this releasing of pressure may cause lose of volatile elements. In this study Teflon bottles are designed with relatively thicker wall compared to commercial ones and a silicone based polymer was used to prepare an O-ring which plays the role of safety valve. In this design, eight vessels are located in an ABS holder to keep them stable and safe. The advantage of these vessels is that they need only 2 mL of HNO3 and 1mL H2O2 to digest different environmental samples, namely, sludge, apple leave, peach leave, spinach leave and tomato leave. In order to investigate the performance of this design an ICP-MS instrument was applied for multi elemental analysis of 20 elements on the SRM of above environmental samples both using this design and a commercial microwave digestion design. Very comparable recoveries were obtained from this simple design with the commercial one. Considering the price of ultrapure chemicals and the amount of them which normally is about 8-10 mL, these simple vessels with the procedures that will be discussed in detail are very cost effective and very suitable for environmental studies.

Keywords: inductively coupled plasma mass spectroscopy (ICP-MS), PTFE vessels, Teflon bombs, microwave digestion, trace element

Procedia PDF Downloads 326

Authors: Nounamo Nguedie Yann Harold

Abstract:

The factors behind the debt have been the subject of several studies in the literature. Pioneering studies based on the 'double deficit' approach linked indebtedness to the imbalance between savings and investment, the budget deficit and the current account deficit. Most studies on identifying factors that may stimulate or reduce the level of external public debt agree that the following variables are important explanatory variables in leveraging debt: the budget deficit, trade opening, current account and exchange rate, import, export, interest rate, term variation exchange rate, economic growth rate and debt service, capital flight, and over-indebtedness. Few studies addressed the impact of political factors on the level of external debt. In general, however, the IMF's stabilization programs in developing countries following the debt crisis have resulted in economic recession and the advent of political crises that have resulted in changes in governments. In this sense, political institutions are recognised as factors of accumulation of external debt in most developing countries. This paper assesses the role of political factors on the external debt level of African countries in the Franc Zone over the period 1985-2016. Data used come from World Bank and ICRG. Using a logit in panel, the results show that the more a country is politically stable, the lower the external debt compared to the gross domestic product. Political stability multiplies 1.18% the chances of being in the sustainable debt zone. For example, countries with good political institutions experience less severe external debt burdens than countries with bad political institutions.

Keywords: African countries, external debt, Franc Zone, political factors

Procedia PDF Downloads 209

Authors: K. Dhanalakshmi, N. Deepak, E. Manikandan, S. Kanagaraj, M. Sulthan Ariff Rahman, P. Chilambarasan C. Abhimanyu, C. A. Akaash Emmanuel Raj, V. R. Sanal Kumar

Abstract:

In this paper using a validated double precision, density-based implicit standard k-ε model, the detailed 2D and 3D numerical studies have been carried out to examine the external flow choking at wing-in-ground (WIG) effect craft. The CFD code is calibrated using the exact solution based on the Sanal flow choking condition for adiabatic flows. We observed that at the identical WIG effect conditions the numerically predicted 2D boundary layer blockage is significantly higher than the 3D case and as a result, the airfoil exhibited an early external flow choking than the corresponding wing, which is corroborated with the exact solution. We concluded that, in lieu of the conventional 2D numerical simulation, it is invariably beneficial to go for a realistic 3D simulation of the wing in ground effect, which is analogous and would have the aspects of a real-time parametric flow. We inferred that under the identical flying conditions the chances of external flow choking at WIG effect is higher for conventional aircraft than an aircraft facilitating a divergent channel effect at the bottom surface of the fuselage as proposed herein. We concluded that the fuselage and wings integrated geometry optimization can improve the overall aerodynamic performance of WIG craft. This study is a pointer to the designers and/or pilots for perceiving the zone of danger a priori due to the anticipated external flow choking at WIG effect craft for safe flying at the close proximity of the terrain and the dynamic surface of the marine.

Keywords: boundary layer blockage, chord dominated ground effect, external flow choking, WIG effect

Procedia PDF Downloads 261

Authors: Ranojoy Dutta, Adam Barker

Abstract:

Multifamily residential buildings are increasingly being built with large glazed areas to provide tenants with greater daylight and outdoor views. However, traditional double-glazed window assemblies can lead to significant thermal discomfort from high radiant temperatures as well as increased cooling energy use to address solar gains. Dynamic glazing provides an effective solution by actively controlling solar transmission to maintain indoor thermal comfort, without compromising the visual connection to outdoors. This study uses thermal simulations across three Canadian cities (Toronto, Vancouver and Montreal) to verify if dynamic glazing along with operable windows and ceiling fans can maintain the indoor operative temperature of a prototype southwest facing high-rise apartment unit within the ASHRAE 55 adaptive comfort range for a majority of the year, without any mechanical cooling. Since this study proposes the use of natural ventilation for cooling and the typical building life cycle is 30-40 years, the typical weather files have been modified based on accepted global warming projections for increased air temperatures by 2050. Results for the prototype apartment confirm that thermal discomfort with dynamic glazing occurs only for less than 0.7% of the year. However, in the baseline scenario with low-E glass there are up to 7% annual hours of discomfort despite natural ventilation with operable windows and improved air movement with ceiling fans.

Keywords: electrochromic glazing, multi-family housing, passive cooling, thermal comfort, natural ventilation

Procedia PDF Downloads 96

Authors: Harikrishna Yadav Nanganuru, Narasimhulu Korrapati

Abstract:

Over the past many years, many sites in the world have been contaminated with heavy metals, which are the largest class of contaminants. Lead is one of the toxic heavy metals contaminated in the environment. Lead is not biodegradable, that’s why it is accumulated in the human body and impacts all the systems of the human body when it has been taken by humans. The accumulation of lead in the water environment has been showing adverse effects on the public health. So the removal of lead from the water environment by the biosorption process, which is emerged as a potential method for the lead removal, is an efficient approach. This work was focused to examine the removal of Lead [Pb (II)] ions from aqueous solution and effluent from battery industry. Lead contamination in water is a widespread problem throughout the world and mainly results from lead acid battery manufacturing effluent. In this work, isolated bacteria from wastewater of lead acid battery industry has been utilized for the removal of lead. First effluent from the lead acid battery industry was characterized by the inductively coupled plasma atomic emission spectrometry (ICP – AES). Then the bacteria was isolated from the effluent and used it’s immobilized dead mass for the biosorption of lead. Scanning electron microscopic (SEM) and Atomic force microscopy (AFM) studies clearly suggested that the Lead (Pb) was adsorbed efficiently. The adsorbed percentage of lead (II) from waste was 97.40 the concentration of lead (II) is measured by Atomic Absorption Spectroscopy (AAS). From the result of AAS it can be concluded that immobilized isolated dead mass was well efficient and useful for biosorption of lead contaminated waste water.

Keywords: biosorption, ICP-AES, lead (Pb), SEM

Procedia PDF Downloads 370

Authors: Japnoor Garcha, Andrew P. Smith

Abstract:

There has been a significant increase in the prevalence and estimates of neurodevelopmental disorders specially autism spectrum disorders in the last decade. The literature has seen increasing research on understanding well-being and mental health. The current studies have focused on seeing the impact of mental health and well-being in autism spectrum disorders and ADHD both with and without a diagnosis. To further understand the association and interaction of well-being and mental health with autism and ADHD a survey was given to 560 secondary school students. The survey used the well-being process questionnaire, the autism spectrum quotient, the ADHD self-report scale, and the strengths and difficulties questionnaire. The analysis conducted using SPSS showed that there was a significant correlation between anxiety, depression, AQ and ADHD. Anxiety and depression were also significantly correlated with all well-being and SDQ variables. The regression analysis showed that anxiety was significantly associated with positive well-being, negative well-being, emotional problems and prosocial behaviour whereas depression was significantly associated with positive well-being, negative well-being, physical health, flourishing, conduct problems, emotional problems and peer problems. This interaction led to the formation of a combined variable to see what impact the variables of anxiety, depression, AQ and ADHD would have coupled together. Further analysis showed that the combined variable was significantly correlated with all outcome variables. The regression analysis showed that the Combined variable was significantly correlated with emotional problems, and hyperactivity, stress, negative coping, psychological capital and sleepiness.

Keywords: AQ, adhd, sdq, well-being, combined variable

Procedia PDF Downloads 44

Authors: Olaide O. Wahab, Lukman O. Olasunkanmi, Krishna K. Govender, Penny P. Govender

Abstract:

The economic and environmental challenges associated with azo disperse dyes applications are due to poor aqueous solubility and low degradation tendency which stems from low chemical reactivity. Poor aqueous solubility property of this group of dyes necessitates the use of dispersing agents which increase operational costs and also release toxic chemical components into the environment, while their low degradation tendency is due to the high stability of the azo functional group (-N=N-) in their chemical structures. To address these problems, this study investigated theoretically the effects of some polar substituents on the aqueous solubility and reactivity properties of disperse yellow (DY) 119 dye with a view to theoretically develop new azo disperse dyes with improved solubility in water and higher degradation tendency in the environment using DMol³ computational code. All calculations were carried out using the Becke and Perdew version of Volsko-Wilk-Nusair (VWN-BP) level of density functional theory in conjunction with double numerical basis set containing polarization function (DNP). The aqueous solubility determination was achieved with conductor-like screening model for realistic solvation (COSMO-RS) in conjunction with known empirical solubility model, while the reactivity was predicted using frontier molecular orbital calculations. Most of the new derivatives studied showed evidence of higher aqueous solubility and degradation tendency compared to the parent dye. We conclude that these derivatives are promising alternative dyes for more economic and environmental benign dyeing practice and therefore recommend them for synthesis.

Keywords: aqueous solubility, azo disperse dye, degradation, disperse yellow 119, DMol³, reactivity

Procedia PDF Downloads 196

Authors: Waseem Al-Talalwah

Abstract:

The superior vesical artery usually arises directly from the anterior division of the internal iliac artery. It may arise from the umbilical artery as three or four branches to supply the upper and middle parts of bladder. Current study focuses on the different origins of the superior vesical artery to provide a sufficient data for surgeons to disease iatrogenic fault. The superior vesical artery arises directly from the anterior division of the internal iliac artery in 24.5% whereas it arises indirectly as from umbilical artery in 83.7%. Further, it may arise from any branch of the anterior division as from the utrine and obturator arteries in 6.1% and in 6.3% respectively. It also shares the origin of the internal pudendal and inferior glutyeal artery as it arises from the gluteopudendal trunk in 4.1%. The superior vesical artery arises as a single, double, triple and quadruple in 69.4%, 20.4%, 8.2% and 2% respectively. In case of cystectomy for bladder cancer, surgeons have to be aware of the origin variability of superior vesical artery to prevent post-surgical complication such as intra-pelvic bleeding. Also, the as intra-pelvic bleeding has to be expected in case of hysterectomy therefore a great caution of the vesical branches arising from uterine artery has to be considered. In case of aneurysm resection of inferior gluteal artery arising from the gluteopudendal trunk, the surgeons have to be careful of the vascular supply of urinary bladder coming from above and below this common trunk as from superior and inferior vesical arteries respectively. Therefore, present study increases the awareness of clinical significance of superior vesical artery origin for surgeons to minimise the iatroginc errors.

Keywords: superior vesical artery, anterior division, internal iliac, internal pudendal, inferior glutyeal, intra-pelvic bleeding, hysterectomy, cystectomy

Procedia PDF Downloads 380

Authors: Yamina Boukari, Nashiru Billa, Andrew Morris, Stephen Doughty, Kevin Shakesheff

Abstract:

Poly (lactic-co-glycolic) acid (PLGA) is a synthetic polymer that can be used in bone tissue engineering with the aim of creating a scaffold in order to support the growth of cells. The formation of microspheres from this polymer is an attractive strategy that would allow for the development of an injectable system, hence avoiding invasive surgical procedures. The aim of this study was to develop a microsphere delivery system for use as an injectable scaffold in bone tissue engineering and evaluate various formulation parameters on its properties. Porous and lysozyme-containing PLGA microspheres were prepared using the double emulsion solvent evaporation method from various molecular weights (MW). Scaffolds were formed by sintering to contain 1 -3mg of lysozyme per gram of scaffold. The mechanical and physical properties of the scaffolds were assessed along with the release of lysozyme, which was used as a model protein. The MW of PLGA was found to have an influence on microsphere size during fabrication, with increased MW leading to an increased microsphere diameter. An inversely proportional relationship was displayed between PLGA MW and mechanical strength of formed scaffolds across loadings for low, intermediate and high MW respectively. Lysozyme release from both microspheres and formed scaffolds showed an initial burst release phase, with both microspheres and scaffolds fabricated using high MW PLGA showing the lowest protein release. Following the initial burst phase, the profiles for each MW followed a similar slow release over 30 days. Overall, the results of this study demonstrate that lysozyme can be successfully incorporated into porous PLGA scaffolds and released over 30 days in vitro, and that varying the MW of the PLGA can be used as a method of altering the physical properties of the resulting scaffolds.

Keywords: bone, microspheres, PLGA, tissue engineering

Procedia PDF Downloads 420

Authors: Prabhavathi Sundaram, Heidi Abrahamse

Abstract:

In recent years, nanotechnology coupled with photodynamic therapy (PDT) has received considerable attention in terms of improving the effectiveness of drug delivery in cancer therapeutics. The development of functionalized single-walled carbon nanotubes (SWCNTs) has become revolutionary in targeted photosensitizers delivery since it improves the therapeutic index of drugs. The objective of this study was to prepare, characterize and evaluate the potential of functionalized SWCNTs using hyaluronic acid and loading it with photosensitizer and to effectively target colon cancer cells. The single-walled carbon nanotubes were covalently functionalized with hyaluronic acid and the loaded photosensitizer by non-covalent interaction. The photodynamic effect of SWCNTs is detected under laser irradiation in vitro. The hyaluronic acid-functionalized nanocomposites had a good affinity with CD44 receptors, and it avidly binds on to the surface of CACO-2 cells. The cellular uptake of nanocomposites was studied using fluorescence microscopy using lyso tracker. The anticancer activity of nanocomposites was analyzed in CACO-2 cells using different studies such as cell morphology, cell apoptosis, and nuclear morphology. The combined effect of nanocomposites and PDT improved the therapeutic effect of cancer treatment. The study suggested that the nanocomposites and PDT have great potential in the treatment of colon cancer.

Keywords: colon cancer, hyaluronic acid, single walled carbon nanotubes, photosensitizers, photodynamic therapy

Procedia PDF Downloads 111