Search results for: residual activity (Q2)

Authors: Edison A. Bonifaz

Abstract:

In this work, a numerical procedure is proposed to design dense multi-material structures using the Directed Energy Deposition (DED) process. A thermo-mechanical finite element model to predict thermal cycles and residual stresses is presented. A numerical layer build-up procedure coupled with a moving heat flux was constructed to minimize strains and residual stresses that result in the multi-layer deposition of an AISI 316 austenitic steel on an AISI 304 austenitic steel substrate. To simulate the DED process, the automated interface of the ABAQUS AM module was used to define element activation and heat input event data as a function of time and position. Of this manner, the construction of ABAQUS user-defined subroutines was not necessary. Thermal cycles and thermally induced stresses created during the multi-layer deposition metal AM pool crystallization were predicted and validated. Results were analyzed in three independent metal layers of three different experiments. The one-way heat and material deposition toolpath used in the analysis was created with a MatLab path script. An optimal combination of feedstock and heat input printing parameters suitable for fabricating multi-material dense structures in the directed energy deposition metal AM process was established. At constant power, it can be concluded that the lower the heat input, the lower the peak temperatures and residual stresses. It means that from a design point of view, the one-way heat and material deposition processing toolpath with the higher welding speed should be selected.

Keywords: event series, thermal cycles, residual stresses, multi-pass welding, abaqus am modeler

Procedia PDF Downloads 39

Authors: Ashkan Golgoon, Souhayl Sadik, Arash Yavari

Abstract:

Eigenstrains in nonlinear solids are created due to anelastic effects such as non-uniform temperature distributions, growth, remodeling, and defects. Eigenstrains understanding is indispensable, as they can generate residual stresses and strongly affect the overall response of solids. Here, we study the residual stress and deformation fields of an incompressible isotropic infinite wedge with a circumferentially-symmetric distribution of finite eigenstrains. We construct a material manifold, whose Riemannian metric explicitly depends on the eigenstrain distribution, thereby we turn the problem into a classical nonlinear elasticity problem, where we find an embedding of the Riemannian material manifold into the ambient Euclidean space. In particular, we find exact solutions for the residual stress and deformation fields of a neo-Hookean wedge having a symmetric inclusion with finite radial and circumferential eigenstrains. Moreover, we numerically solve a similar problem when a symmetric Mooney-Rivlin inhomogeneity with finite eigenstrains is placed in a neo-Hookean wedge. Generalization of the eigenstrain problem to other geometries are also discussed.

Keywords: finite eigenstrains, geometric mechanics, inclusion, inhomogeneity, nonlinear elasticity

Procedia PDF Downloads 229

Authors: Hao Chen, Bo Guo, Ping Jiang

Abstract:

Residual life (RL) estimation based on multi-phase nonlinear Wiener process was studied in this paper, which is significant for complicated products with small samples. Firstly, nonlinear Wiener model with random parameter was introduced and multi-phase nonlinear Wiener model was proposed to model degradation process of products that were nonlinear and separated into different phases. Then the multi-phase RL probability density function based on the presented model was derived approximately in a closed form and parameters estimation was achieved with the method of maximum likelihood estimation (MLE). Finally, the method was applied to estimate the RL of high voltage plus capacitor. Compared with the other three different models by log-likelihood function (Log-LF) and Akaike information criterion (AIC), the results show that the proposed degradation model can capture degradation process of high voltage plus capacitors in a better way and provide a more reliable result.

Keywords: multi-phase nonlinear wiener process, residual life estimation, maximum likelihood estimation, high voltage plus capacitor

Procedia PDF Downloads 427

Authors: Zhiqiang Cheng, Qingliang He, Lu Li, Jie Ren

Abstract:

The safety of pipelines in the condition of frost heave or thaw settlement is necessarily evaluated. A full-scale experiment pipe with the typical structure configuration in station pipeline is constructed, the residual stress is tested with X-ray residual stress device, and the residual stress field of pipe is analyzed. The evolution of pipe strain with pressure in the scope of maximum allowable operation pressure (MAOP) is investigated by both strain gauge and X-ray methods. Load caused by frost heave or thaw settlement is simulated by two ways of lifting jack. The relation of maximum stress of pipe and clearances between supporter and pipe is studied in case of frost heave. The relation of maximum stress of pipe and maximum deformation of pipe on the ground is studied in case of thaw settlement. The study methods and results are valuable for safety assessment of station pipeline according to clearances or deformation in the condition of frost heave or thaw settlement.

Keywords: frost heave, pipeline, stress analysis, thaw settlement

Procedia PDF Downloads 159

Authors: Rabitah Zakaria, Chan M. Luan, Nor Hakimah Ramly

Abstract:

The extraction of vegetable oil using aqueous extraction process assisted by ionic extended surfactant has been investigated as an alternative to hexane extraction. However, the ionic extended surfactant has not been commercialised and its safety with respect to food processing is uncertain. Hence, food-grade non-ionic surfactants (Tween 20, Span 20, and Span 80) were proposed for the extraction of residual oil from palm-pressed mesocarp fibre. Palm-pressed mesocarp fibre contains a significant amount of residual oil ( 5-10 wt %) and its recovery is beneficial as the oil contains much higher content of vitamin E, carotenoids, and sterols compared to crude palm oil. In this study, the formulation of food-grade surfactants using a combination of high hydrophilic-lipophilic balance (HLB) surfactants and low HLB surfactants to produce micro-emulsion with very low interfacial tension (IFT) was investigated. The suitable surfactant formulation was used in the oil extraction process and the efficiency of the extraction was correlated with the IFT, droplet size and viscosity. It was found that a ternary surfactant mixture with a HLB value of 15 (82% Tween 20, 12% Span 20 and 6% Span 80) was able to produce micro-emulsion with very low IFT compared to other HLB combinations. Results suggested that the IFT and droplet size highly affect the oil recovery efficiency. Finally, optimization of the operating parameters shows that the highest extraction efficiency of 78% was achieved at 1:31 solid to liquid ratio, 2 wt % surfactant solution, temperature of 50˚C, and 50 minutes contact time.

Keywords: food-grade surfactants, aqueous extraction of residual oil, palm-pressed mesocarp fibre, interfacial tension

Procedia PDF Downloads 369

Authors: Jianhong Xiang, Rui Sun, Linyu Wang

Abstract:

In recent years, due to the continuous improvement of deep learning theory, Convolutional Neural Network (CNN) has played a great superior performance in the research of Hyperspectral Image (HSI) classification. Since HSI has rich spatial-spectral information, only utilizing a single dimensional or single size convolutional kernel will limit the detailed feature information received by CNN, which limits the classification accuracy of HSI. In this paper, we design a multi-scale CNN with MLP based on residual and attention modules (INRAM-3DCNN) for the HSI classification task. We propose to use multiple 3D convolutional kernels to extract the packet feature information and fully learn the spatial-spectral features of HSI while designing residual 3D convolutional branches to avoid the decline of classification accuracy due to network degradation. Secondly, we also design the 2D Inception module with a joint channel attention mechanism to quickly extract key spatial feature information at different scales of HSI and reduce the complexity of the 3D model. Due to the high parallel processing capability and nonlinear global action of the Multilayer Perceptron (MLP), we use it in combination with the previous CNN structure for the final classification process. The experimental results on two HSI datasets show that the proposed INRAM-3DCNN method has superior classification performance and can perform the classification task excellently.

Keywords: INRAM-3DCNN, residual, channel attention, hyperspectral image classification

Procedia PDF Downloads 41

Authors: D. Jagath Kumari, K. Srinivasa Rao

Abstract:

Quality assurance of the structures subjected to high temperatures is now enforcing measure for the Structural Engineers. The existing relations between strength and nondestructive measurements have been established under normal conditions are not suitable to concretes that have been exposed to high temperatures. The scope of the work is to investigate the influence of high temperatures of short durations on the residual properties of reinforced HVFA concrete columns that affect the strength by non-destructive tests (NDT). Fly ash concrete is increasingly used in the design of normal strength, high strength and high performance concretes. In this paper, the authors revealed the influence of high temperatures on HVFA concrete columns. These columns are heated from 100oC to 800oC with increments of 100oC and allowed to cool to room temperature by two methods one is air cooling method and the other immediate water quenching method. All the specimens were tested identically, before heating and after heating for compressive strength and material integrity by rebound hammer and ultrasonic pulse velocity (UPV) meter respectively. HVFA concrete retained more residual strength by water quenching method than air-cooling method.

Keywords: HVFA concrete, NDT methods, residual strength, non-destructive tests

Procedia PDF Downloads 432

Authors: Ferruh Taspinar, Gulce K. Seyyar, Gamze Kurt, Eda O. Okur, Emrah Afsar, Ismail Saracoglu, Betul Taspinar

Abstract:

Alterations of physical activity can effect body composition (especially body fat ratio); however body mass index may not sufficient to indicate these minimal differences. The aim of this study was to evaluate the relationship between body composition and physical activity in university students. In this study, 132 university students (mean age; 21.21±1.51) were included. Tanita BC-418 and International Physical Activity Questionnaire (IPAQ) were used to evaluate participants. The correlation between the parameters was analysed via Spearman correlation analysis. Significance level in statistical analyses was accepted is 0.05. The results showed that there was no correlation between body mass index and physical activity (p>0.05). There was a positive correlation between body muscle ratio and physical activity, whereas a negative correlation between body fat ratio and physical activity (p<0.05). This study showed that body fat and muscle ratio affects the level of physical activity in healthy university students. Therefore, we thought that physical activity might reduce effects of the diseases caused by disturbed body composition. Further studies are required to support this idea.

Keywords: body composition, body mass index, physical activity, university student

Procedia PDF Downloads 331

Authors: Wanthani Paengsri, Thanyarat Chuesaard, Napapha Promsawan

Abstract:

Spilanthes acmella Murr. was extracted with methanol, yielding methanol crude extract 5.86 %w/w. This study aimed to examine the chemical composition and antioxidant activity of methanolic crude extract. The chemical composition of methanolic crude extract was analyzed by gas chromatography-mass spectrometry (GC-MS). The predominant components were found to be palmitic acid (40.08%), 2-hexadecanoyl glycerol (6.96%) and octadecanoic acid (4.06%). Antioxidant activity was determined using 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical, for evaluating free radicle scavenging activity. The methanolic extract at 150 µg/mL showed an antioxidant activity with high of radical scavenging activity (75.23%).

Keywords: antioxidant activity, GC-MS analysis, Spilanthes, Phak-Kratt Hauwaen

Procedia PDF Downloads 496

Authors: F. Pottmeyer, M. Weispfenning, K. A. Weidenmann

Abstract:

Continuous carbon fiber reinforced plastics (CFRP) exhibit a high application potential for lightweight structures due to their outstanding specific mechanical properties. Embedded metal elements, so-called inserts, can be used to join structural CFRP parts. Drilling of the components to be joined can be avoided using inserts. In consequence, no bearing stress is anticipated. This is a distinctive benefit of embedded inserts, since continuous CFRP have low shear and bearing strength. This paper aims at the investigation of the load bearing capacity after preinduced damages from impact tests and thermal-cycling. In addition, characterization of mechanical properties during dynamic high speed pull-out testing under different loading velocities was conducted. It has been shown that the load bearing capacity increases up to 100% for very high velocities (15 m/s) in comparison with quasi-static loading conditions (1.5 mm/min). Residual strength measurements identified the influence of thermal loading and preinduced mechanical damage. For both, the residual strength was evaluated afterwards by quasi-static pull-out tests. Taking into account the DIN EN 6038 a high decrease of force occurs at impact energy of 16 J with significant damage of the laminate. Lower impact energies of 6 J, 9 J, and 12 J do not decrease the measured residual strength, although the laminate is visibly damaged - distinguished by cracks on the rear side. To evaluate the influence of thermal loading, the specimens were placed in a climate chamber and were exposed to various numbers of temperature cycles. One cycle took 1.5 hours from -40 °C to +80 °C. It could be shown that already 10 temperature cycles decrease the load bearing capacity up to 20%. Further reduction of the residual strength with increasing number of thermal cycles was not observed. Thus, it implies that the maximum damage of the composite is already induced after 10 temperature cycles.

Keywords: composite, joining, inserts, dynamic loading, thermal loading, residual strength, impact

Procedia PDF Downloads 251

Authors: Rachid Kacem, Sara Talbi, Yasmina Hemissi, Sofia Bouguattoucha

Abstract:

The aim of the present work is the evaluation of the antioxidant activity of the Peganum harmala (P. harmala) seeds extracts. The antioxidant activity was evaluated by applying two methods, the method of ß-carotene bleaching and DPPH (2, 2-Diphenyl-1-Picryl-Hydrazyl). Using Folin-Ciocalteu assay, these results revealed that the concentration of polyphenols in EthOH E. (122.28 ± 2.24 µg GAE/mg extract) is the highest. The antiradical activity of the P. harmala seeds extracts on DPPH was found to be dose dependent with polyphenols concentration. The E. EthOH extract showed the highest antioxidant activity (IC = 252.10 ± 11.18 μg /ml). The test of β-carotene bleaching indicates that the E. EthOH of P. harmala showed the highest percentage of the antioxidant activity (49.88 %).

Keywords: antioxidant activity, Peganum harmala, polyphenols, flavonoids

Procedia PDF Downloads 472

Authors: Maryam Samani. Ahmad Golchin. Hosseinali Alikkani. Ahmad Baybordi

Abstract:

Natural diatomite was modified by grinding and acid treatment to increase surface area and to decrease the impurities. Surface area and pore volume of the modified diatomite were 67.45 m² g-1 and 0.105 cm³ g-¹ respectively, and used to immobilize Pb, Zn and Cu in an urban soil. The modified diatomite was added to soil samples at the rates of 2.5, 5, 7.5 and 10% and the samples incubated for 60 days. The addition of modified diatomite increased SSA of the soil. The SSAs of soils with 2.5, 5.0, 7.5 and 10% modified diatomite were 20.82, 22.02, 23.21 and 24.41 m² g-¹ respectively. Increasing the SSAs of the soils by the application of modified diatomite reduced the DTPA extractable concentrations of heavy metals compared with un-amendment control. The concentration of Pb, Zn and Cu were reduced by 91.1%, 82% and 91.1% respectively. Modified diatomite reduced the concentration of Exchangeable and Carbonate bounded species of Pb, Zn and Cu, compared with the control. Also significantly increased the concentration of Fe Mn- OX (Fe-Mn Oxides) and OM (Organic Matter) bound and Res (Residual) fraction. Modified diatomite increased the urease, dehydrogenase and alkaline phosphatase activity by 52%, 57% and 56.6% respectively.

Keywords: modified diatomite, chemical specifications, specific surface area, enzyme activity, immobilization, heavy metal, soil remediation

Procedia PDF Downloads 25

Authors: M. Ndaw, G. Mendy, S. Ouya

Abstract:

Risk management in banking sector is a key issue linked to financial system stability and its importance has been elevated by technological developments and emergence of new financial instruments. In this paper, we improve the model previously defined for quantifying internal control impact on banking risks by automatizing the residual criticality estimation step of FMECA. For this, we defined three equations and a maturity coefficient to obtain a mathematical model which is tested on all banking processes and type of risks. The new model allows an optimal assessment of residual criticality and improves the correlation rate that has become 98%.

Keywords: risk, control, banking, FMECA, criticality

Procedia PDF Downloads 293

Authors: Kamel Zemour, Kada Mohamed Amine Chouhim, Mohamed Mairif, Tadj Eddine Adda Ardjan

Abstract:

Many recent studies show the positive effect of phenolic compounds in olive oil on health. They are known for their biological properties, where they have shown potential activity as an antioxidant, anti-inflammatory, and antimicrobial agents. However, this characteristic is rarely studied in olive oil from different regions of Algeria. Different samples collected from the western region of Algeria were evaluated for their polyphenol content, antioxidant activity, and antimicrobial effect. The obtained results demonstrated that this oil is rich in polyphenols and revealed high antimicrobial activity against Staphylococcus aureus and Escherichia coli. Finally, this study has highlighted the nutritional and pharmaceutical importance of olive oil grown in Algeria.

Keywords: olive oil, polyphenols, antioxidant activity, antimicrobial activity

Procedia PDF Downloads 112

Authors: Nilüfer Yıldız Varan

Abstract:

The antimicrobial activities of chitosan against various bacteria and fungi are well known, and the antimicrobial activity of chitosan depends on pH. This study investigates the antimicrobial activity at different pH levels. Nylon 6,6 fabrics were treated with different chitosan solutions. Additionally, samples were treated also in basic conditions to see the antimicrobial activities. AATCC Test Method 100 was followed to evaluate the antimicrobial activity using Staphylococcus aureus ATCC 6538 test inoculum. The pH of the chitosan solutions was controlled below 6.5 since chitosan shows its antimicrobial activity only in acidic conditions because of its poor solubility above 6.5. In basic conditions, the samples did not show any antimicrobial activity. It appears from SEM images that the bonded chitosan in the structures exists. In acidic media (ph < 6.5), all samples showed antimicrobial activity. No correlation was found between pH levels and antimicrobial activity in acidic media.

Keywords: chitosan, nylon 6, 6, crosslinking, pH stability, antimicrobial

Procedia PDF Downloads 192

Authors: Wirot Likittrakulwong, Pisit Poolprasert, Tossaporn Incharoen

Abstract:

Germinated paddy rice (GPR) has the potential to be used as a feed ingredient. However, their properties have not been fully investigated. This paper examined the nutrient digestibility and the relationship to immune activity in Roman hens fed with GPR. It was found that true and apparent metabolizable energy (ME) values of GPR were 3.20 and 3.28 kcal/g air dry, respectively. GPR exhibited high content of phytonutrients, especially GABA. GPR showed similar protein profiles in comparison to non-germinated paddy rice. For immune activity, the feed with GPR enhanced the immune activity of Roman hens under high stocking density stress as evidenced by the activity of superoxide dismutase (SOD) and lysozyme activity. In this study, GPR is proved to be a good source of functional ingredient for chicken feed.

Keywords: germinated paddy rice, nutrient digestibility, immune activity, functional property

Procedia PDF Downloads 135

Authors: Rock-Hyun Choi, Won-Seok Kang, Chang-Sik Son

Abstract:

Physical activity is important for healthy living. Recently wearable devices which motivate physical activity are quickly developing, and become cheaper and more comfortable. In particular, fitness trackers provide a variety of information and need to provide well-analyzed, and user-friendly results. In this study, frequency analysis was performed to classify various data sets of Fitbit into simple activity status. The data from Fitbit cloud server consists of 263 subjects who were healthy factory and office workers in Korea from March 7th to April 30th, 2016. In the results, we found assumptions of activity state classification seem to be sufficient and reasonable.

Keywords: activity status, fitness tracker, heart rate, steps

Procedia PDF Downloads 357

Authors: Chanchai Wimon, Polin Muangngam, Thannapat Nimsumram, Chanin Prombutra, Prasert Aengchuan, Perawat Boonpuek

Abstract:

Cleaning water containers is essential for drinking water production to prevent contamination and residual chemicals from washing liquid. Water distribution divisions in Thailand are facing a critical problem with residual contamination in 15-liter drinking water containers due to dust and residual chemicals (TDS value > 200) after normal washing. A thorough washing process is required before filling the purified water into each container. Unfortunately, the washing procedure and frequency do not align with the work instructions provided by the health department. The measured Total Dissolved Solids (TDS) value of the remaining water was found to range between 195–202, exceeding the standard TDS for excellent drinking water (50-190 ppm). This research uses the design of experiment technique in statistics to improve the washing process and reduce such contamination. Statistical data from our survey of the cleaning process is collected to identify affecting factors. Washing time and water volume are varied to test the efficiency of the washing process in reducing residual sediment in the water. The result indicates that cleaning the 15-liter container with 2 liters of tap water mixed with 15 milliliters of dishwashing liquid for 3.12 minutes per container is optimal, as the resulting TDS reduces to 189.75, falling within the standard value for good drinking water. This study result would benefit the drinking water industry in implementing a statistically evaluated cleaning procedure without conducting multiple trials, thus saving takt time and production costs.

Keywords: design of experiment, drinking water purification, quality management, production process reliability

Procedia PDF Downloads 19

Authors: Boonsiri Dandumrongsin, Halis Simsek, Chaiwat Rongsayamanont

Abstract:

Dissolved organic nitrogen (DON) is known as one of the persistence nitrogenous pollutant being originated from secondary treated effluent of municipal sewage treatment plant. However, effect of key system operating condition on the fate and behavior of residual DON in the treated effluent is still not known. This study aims to investigate effect of organic loading rate (OLR) on the residual level of DON in the biofilm reactor effluent. Synthetic municipal wastewater was fed into moving bed biofilm reactors at OLR of 1.6x10-3 and 3.2x10-3 kg SCOD/m3-d. The results showed higher organic removal efficiency was found in the reactor operating at higher OLR. However, DON was observed at higher value in the effluent of the higher OLR reactor than that of the lower OLR reactor evidencing a clear influence of OLR on the residual DON level in the treated effluent of the biofilm reactors. It is possible that the lower DON being observed in the reactor at lower OLR is likely to be a result of providing the microbe with the additional period for utilizing the refractory DON molecules during operation at lower organic loading. All the experiments were repeated using raw wastewaters and similar trend was obtained.

Keywords: dissolved organic nitrogen, hydraulic retention time, moving bed biofilm reactor, soluble microbial products

Procedia PDF Downloads 254

Authors: I. D. Laryushin, V. A. Kostin, A. A. Silaev, N. V. Vvedenskii

Abstract:

Generation of broadband intense terahertz (THz) radiation attracts reasonable interest due to various applications, such as the THz time-domain spectroscopy, the probing and control of various ultrafast processes, the THz imaging with subwavelength resolution, and many others. One of the most promising methods for generating powerful and broadband terahertz pulses is based on focusing two-color femtosecond ionizing laser pulses in gases, including ambient air. For this method, the amplitudes of terahertz pulses are determined by the free-electron current density remaining in a formed plasma after the passage of the laser pulse. The excitation of this residual current density can be treated as multi-wave mixing: Аn effective generation of terahertz radiation is possible only when the frequency ratio of one-color components in the two-color pulse is close to irreducible rational fraction a/b with small odd sum a + b. This work focuses on the optimal parameters (polarizations and intensities) of laser components for the strongest THz generation. The optimal values of parameters are found numerically and analytically with the use of semiclassical approach for calculating the residual current density. For frequency ratios close to a/(a ± 1) with natural a, the strongest THz generation is shown to take place when the both laser components have circular polarizations and equal intensities. For this optimal case, an analytical formula for the residual current density was derived. For the frequency ratios such as 2/5, the two-color ionizing pulses with circularly polarized components practically do not excite the residual current density. However, the optimal parameters correspond generally to specific elliptical (not linear) polarizations of the components and intensity ratios close to unity.

Keywords: broadband terahertz radiation, ionization, laser plasma, ultrashort two-color pulses

Procedia PDF Downloads 183

Authors: L. Mallesha, C. S. Karthik, P. Mallu

Abstract:

A series of new [1-(substituted-benzoyl)-piperidin-4-yl]-(2,4-difluoro-phenyl)-methanone oxime derivatives, 3(a-f) were synthesized and characterized by different spectral studies. All compounds were evaluated for their in vitro antibacterial activity against bacterial strains. These compounds were screened for their antioxidant activity by DPPH• and Fe2+ chelating assay. Antiproliferative effects were evaluated using the MTT assay method against two human cancer cell lines and one astrocytoma brain tumor cell line. Compound 3b exhibited moderate antibacterial activity when compared with other compounds. All the compounds showed antioxidant activity, where compound 3f was the best radical scavenger and Fe2+ ion scavenger. Compounds, 3b, and 3d showed good activity on all cell lines, whereas the other compounds in the series exhibited moderate activity.

Keywords: Piperidine, antibacterial, antioxidant, antiproliferative

Procedia PDF Downloads 381

Authors: Dongjoo Kim

Abstract:

Effective control of sloshing in a liquid container is an important issue to be resolved in many applications. In this study, numerical simulations are performed to design the velocity profile of rectangular container and investigate the effectiveness of input shaping for sloshing control. Trapezoidal profiles of container velocity are chosen to be reference commands and they are convolved with a series of impulses to generate shaped ones that induce minimal residual oscillations. The performances of several input shapers are compared from the viewpoint of transient peak and residual oscillations of sloshing. Results show that sloshing can be effectively controlled by input shaping (Supported by the NRF programs, NRF-2015R1D1A1A01059675, of Korean government).

Keywords: input shaping, rectangular container, sloshing, trapezoidal profile

Procedia PDF Downloads 231

Authors: Turk Ayman, Ahn Jong Hoon, Khalife K. Hala, Gali-Muhtasib Hala, Lee Mi Kyeong

Abstract:

Laurus nobilis is an aromatic plant widely distributed in the Mediterranean region. The leaves of this plant are frequently used as a spice and as a traditional medicine for several diseases. In our present study, the methanolic extract of L. nobilis leaves showed antioxidant activity. Chromatographic separations of the EtOAc fraction which had the highest antioxidant activity led to the isolation of 12 compounds. Among them, there was a new phenylpropanoid derivative, which was identified by 1D and 2D NMR experiments, as well as high resolution mass spectrometry. In addition, two major compounds, catechin and epicatechin, which showed strong antioxidant activity may be responsible for the antioxidant activity of L. nobilis leaves. Since different plant parts may contain different types of constituents which contribute to the biological activities, we investigated the antioxidant activity of different parts of L. nobilis such as leaves, stems and fruits. Stems of L. nobilis showed the most potent antioxidant activity, followed by leaves. Further quantitation of total phenol and flavonoids contents revealed a positive correlation between the content of these compounds and antioxidant activity. Taken together, phenolic compounds including flavonoids are responsible for antioxidant activity of L. nobilis. In addition, stem parts of L. nobilis are suggested as good sources for antioxidant activity. Conclusively, L. nobilis might be effective in several free radical mediated diseases.

Keywords: antioxidant activity, different parts, Laurus nobilis, phenolic compound

Procedia PDF Downloads 268

Authors: Harshadkumar Rajgor, Jeff Butterworth

Abstract:

Background: Barretts oesophagus increases the risk of developing oesophageal adenocarcinoma. Over the last 40 years, there has been a 6 fold increase in the incidence of oesophageal adenocarcinoma in the western world and the incidence rates are increasing at a greater rate than cancers of the colon, breast and lung. Endoscopic mucosal resection (EMR) is a relatively new technique being used by 2 centres in the greater midlands cancer network. EMR can be used for curative or staging purposes, for high-grade dysplasia’s and T1 tumours of the oesophagus. EMR is also suitable for those who are deemed high risk for oesophagectomy. EMR has a recurrence rate of 21% according to the Wiesbaden data. Method: A retrospective study of prospectively collected data was carried out involving 24 patients who had EMR for curative or staging purposes. Complications of residual or recurrent disease following EMR that required further treatment were investigated. Results: In 54% of cases residual or recurrent disease was suspected. 96% of patients were given clear and concise information regarding their diagnosis of high-grade dysplasia or T1 tumours. All 24 patients consulted the same specialist healthcare team. Conclusion: EMR is a safe and effective treatment for patients who have high-grade dysplasia and T1NO tumours. In 54% of cases residual or recurrent disease was suspected. Initially, only single resections were undertaken. Multiple resections are now being carried out to reduce the risk of recurrence. Complications from EMR remain low in this series and consisted of a single episode of post procedural bleeding.

Keywords: endoscopic mucosal resection, oesophageal dysplasia, T1 tumours, cancer network

Procedia PDF Downloads 297

Authors: Dipti Yadav, Latha Rangan, Pinakeswar Mahanta

Abstract:

Recent fuel-development strategies to reduce oil dependency, mitigate greenhouse gas emissions, and utilize domestic resources have generated interest in the search for alternative sources of fuel supplies. Bioenergy production from lignocellulosic biomass has a great potential. Cellulose, hemicellulose and Lignin are main constituent of woods or agrowaste. In all the industries there are always left over or waste products mainly lignin, due to the heterogeneous nature of wood and pulp fibers and the heterogeneity that exists between individual fibers, no method is currently available for the quantitative isolation of native or residual lignin without the risk of structural changes during the isolation. The potential benefits from finding alternative uses of lignin are extensive, and with a double effect. Lignin can be used to replace fossil-based raw materials in a wide range of products, from plastics to individual chemical products, activated carbon, motor fuels and carbon fibers. Furthermore, if there is a market for lignin for such value-added products, the mills will also have an additional economic incentive to take measures for higher energy efficiency. In this study residual lignin were isolated from areca nut shells by acid hydrolysis and were analyzed and characterized by Fourier Transform Infrared (FTIR), LCMS and complexity of its structure investigated by NMR.

Keywords: Areca nut, Lignin, wood, bioenergy

Procedia PDF Downloads 452

Authors: Muhammad Wahb

Abstract:

Physical activity is increasingly recognized as a significant factor in maintaining optimal health and preventing chronic diseases. This research scrutinizes the long-term health benefits of sustained physical activity, employing a systematic review of epidemiological studies and randomized control trials conducted over the past decade. The study illuminates the protective effects of regular physical activity against cardiovascular disease, obesity, diabetes, and mental health disorders, with a special focus on the mechanisms involved. Furthermore, the paper provides insights into how public health initiatives can effectively promote physical activity among diverse populations, contributing to improved community health outcomes.

Keywords: physical activity, long-term health benefits, chronic disease prevention, public health

Procedia PDF Downloads 63

Authors: Hajar Al Rajaibi, Kawla Al Toubi, Saeed Al Jaadi, Deepali Jaju, Sanjay Jaju

Abstract:

Background: The available evidence in Oman on lack of physical activity call for immediate intervention. Physical activity counseling by doctors to their patients is influenced by their attitudes and personal physical fitness. To our best knowledge, the physical activity status of Omani medical students has not been addressed before. These future doctors will have a critical role in improving physical activity in patients and thus their overall health. Objective: The aim of the study is to assess the physical activity level, physical fitness level, and attitudes towards physical activity among Sultan Qaboos University senior medical students. Methods: In this cross-sectional study (N=110; males 55), physical activity level was assessed using International Physical Activity Questionnaire (IPAQ ) short form and attitudes towards physical activity using a fifty-four-items Kenyon questionnaire. The physical fitness level was assessed by estimating maximal oxygen uptake (VO₂max) using Chester step test. Results: Female students reported more sitting time more than 7hr/day (85.5%) compared to male students (40%; p < 0.05). The IPAQ revealed moderate level of physical activity in 58% of students. Students showed a high positive attitude towards physical activity for health and fitness and low attitude for physical activity as tension and risk. Both female and male students had a similar level and attitude towards physical activity. Physical fitness level was excellent (VO₂max > 55ml O₂/kg/min) in 11% of students, good (VO₂max>44-54ml O₂/kg/min) in 49% and average to below-average in 40%. Objectively measured physical fitness level, subjectively reported physical activity level or attitudes towards physical activity were not correlated. Conclusion: Omani medical students have a positive attitude towards physical activity but moderate physical activity level. Longer sitting time in females need further evaluation. Efforts are required to understand reasons for present physical activity level and to promote good physical activity among medical students by creating more awareness and facilities.

Keywords: Chester step test, Kenyon scale, medical students, physical activity, physical fitness

Procedia PDF Downloads 129

Authors: Faezeh Aghazadeh

Abstract:

The catalytic activity of Pt/γ-Al₂O₃ and Pt-Fe/γ-Al₂O₃ catalysts was investigated to bring about the complete oxidation of 2-Propanol. Among them, Pt-Fe/γ-Al₂O₃ was found to be the most promising catalyst based on activity. The catalysts were characterized by (XRD), (SEM), (TEM) and ICP-AES techniques. Iron loadings on Pt/γ-Al₂O₃ had a great effect on catalytic activity, and Pt-Fe/γ-Al₂O₃ (1.75 wt% Fe) catalyst at calcination temperature 300°C was observed to be the most active, which might be contributed to the favorable synergetic effects between Pt and Fe, high activity and the well-dispersed bimetallic phase. The combustion of 2-Propanol in the vapor phase was carried out in a conventional flow U-shape glass reactor used in the differential mode at atmospheric pressure. 2-Propanol was analyzed by a gas chromatograph VARIAN 3800 CX equipped with an FID. As observed, better performance and activity were observed for Pt-Fe/Al₂O₃ bimetallic catalyst. These results indicate that the high dispersion on support gives a positive effect on catalytic activity.

Keywords: volatile organic compounds, bimetallic catalyst, catalytic activity, low temperature

Procedia PDF Downloads 115

Authors: Bouchenak Fatima, Lmegharbi Abdelbaki, Houssem Degaichia, Benrebiha Fatima

Abstract:

The essential oil composition of the leaf of Artemisia absinthium from region of Cherchell (The south of Algeria) was investigated by GC, GC-MS. 27 constituents were identified correspond to 84, 63% of the total oil. The major components are Thujone (60, 82%), Chamazulènel (16, 62%), ρ-cymène (4, 29%) and 2-carène (4.25%). The antimicrobial activity of oil was tested in vitro by two methods (agar diffusion and microdilution) on three plant pathogenic fungi. This oil has been tested for antimicrobial activity against three pathogenic fungi (Botrytis cinerea, Fusarium culmorum and Helminthosporium Sp.).The study of activity was evaluated by two methods: Method of diffusion in gelose and the minimum inhibitory concentration MIC. This oil exhibited an interesting antimicrobial activity. A preliminary study showed that this oil presented high toxicity against this fungus. These results, although preliminary show a good antifungal activity, to limit and inhibit stop the development of those pathogen agent.

Keywords: artemisia absinthian, extraction process, chemical study, antifungal activity

Procedia PDF Downloads 441

Authors: Mahta Eskandarnejad

Abstract:

The aim of this paper was to compare physical activity and mental toughness in the staff and students of the University of Tabriz. 615 people participated in this study and filled demographic questionnaire, mental thoughness48 (MTQ48) questionnaire and habitual physical activity questionnaire (Baecke physical activity questionnaire). The research sample included 355 students and 260 staff (615 questionnaires). For analyzing hypotheses MANOVA, correlation and independent t-test were used. Based on the result; some subscales of mental toughness and physical activity were significantly related. The result showed the significant correlation between mental toughness and physical activity in student and no significant correlation in staff. Students were significantly physically more active than staff, and mental toughness was higher in staff. There was no difference in mental toughness variable between active participants (active staff and student). The results of this study showed that mental toughness could influence the way a person cope with living conditions. It is expected that mental toughness changes can lead to changing in levels of physical activity. It should be noted that the other variables should not be ignored.

Keywords: Baecke physical activity questionnaire, mental toughness, physical activity, university staff, university student

Procedia PDF Downloads 362