Search results for: ratio of the L6/L7 length

Authors: H. Mokaddem, D. Miroud, N. Azouaou, F. Si-Ahmed, Z. Sadaoui

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The synthesis and characterization of activated carbon from local lignocellulosic precursor (Algerian alfa) was carried out for the removal of cationic dyes from aqueous solutions. The effect of the production variables such as impregnation chemical agents, impregnation ratio, activation temperature and activation time were investigated. Carbon obtained using the optimum conditions (CaCl2/ 1:1/ 500°C/2H) was characterized by various analytical techniques scanning electron microscopy (SEM), infrared spectroscopic analysis (FTIR) and zero-point-of-charge (pHpzc). Adsorption tests of methylene blue on the optimal activated carbon were conducted. The effects of contact time, amount of adsorbent, initial dye concentration and pH were studied. The adsorption equilibrium examined using Langmuir, Freundlich, Temkin and Redlich–Peterson models reveals that the Langmuir model is most appropriate to describe the adsorption process. The kinetics of MB sorption onto activated carbon follows the pseudo-second order rate expression. The examination of the thermodynamic analysis indicates that the adsorption process is spontaneous (ΔG ° < 0) and endothermic (ΔH ° > 0), the positive value of the standard entropy shows the affinity between the activated carbon and the dye. The present study showed that the produced optimal activated carbon prepared from Algerian alfa is an effective low-cost adsorbent and can be employed as alternative to commercial activated carbon for removal of MB dye from aqueous solution.

Keywords: activated carbon, adsorption, cationic dyes, Algerian alfa

Procedia PDF Downloads 228

Authors: Zishan Ahmad, Anwar Shahzad

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The present studies describe a protocol for high frequency in vitro propagation through nodal segments and shoot tips in D. arayalpathra, a critically endangered medicinal liana of the Western Ghats, India. Nodal segments were more responsive than shoot tips in terms of shoot multiplication. Murashige and Skoog’s (MS) basal medium supplemented with 2.5 µM 6-benzyladenine (BA) was optimum for shoot induction through both the explants. Among different combinations of plant growth regulator (PGRs) and growth additive screened, MS medium supplemented with BA (2.5 µM) + indole-3-acetic acid (IAA) (0.25 µM) + adenine sulphate (ADS) (10.0 µM) induced a maximum of 9.0 shoots per nodal segment and 3.9 shoots per shoot tip with mean shoot length of 8.5 and 3.9 cm respectively. Half-strength MS medium supplemented with Naphthaleneacetic acid (NAA) (2.5 µM) was the best for in vitro root induction. After successful acclimatization in SoilriteTM, 92 % plantlets were survived in field conditions. Acclimatized plantlets were studied for chlorophyll and carotenoid content, net photosynthetic rate (PN) and related attributes such as stomatal conductance (Gs) and transpiration rate during subsequent days of acclimatization. The rise and fall of different biochemical enzymes (SOD, CAT, APX and GR) were also studies during successful days of acclimatization. Moreover, the effect of acclimatization on the synthesis of 2-hydroxy-4-methoxy benzaldehyde (2H4MB) was also studied in relation to the biomass production. Maximum fresh weight (2.8 gm/plant), dry weight (0.35 gm/plant) of roots and 2H4MB content (8.5 µg/ ml of root extract) were recorded after 8 weeks of acclimatization. The screening of in vitro raised plantlet root was also carried out by using GC-MS analysis which witnessed more than 25 compounds. The regenerated plantlets were also screened for homogeneity by using RAPD and ISSR. The proposed protocol surely can be used for the conservation and commercial production of the plant.

Keywords: 6-benzyladenine, PGRs, RAPD, 2H4MB

Procedia PDF Downloads 194

Authors: Melliti Rihab, Zaeid Sonia, Khechine Wiem, Daldoul Amira

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Introduction: Lung cancer is the leading cause of cancer death. Its incidence is increasing, and its prognosis remains pejorative. We present the clinical, pathological, and therapeutic characteristics of bronchopulmonary cancer (BPC) in Tunisia. Methods: Retrospective study including patients followed in the oncology department of the University Hospital of Monastir between April 2014 and December 2021 suffering from lung cancer. Results: These are 117 patients, including 86.3% men and 13.7% women (sex ratio 6.3). The average age was 64 years ± 9 (37-83), with 95.7% being over 50 years old. Patients were smokers in 82% of cases. The clinical signs were dominated by chest pain (27.5%) and dyspnea in 21.1% of cases. In 6 patients, an episode of COVID-19 infection revealed the diagnosis. Half of the patients had a PS between 0 and 1. Small cell lung cancer was present in 18 patients (15.4%). The majority of non small cell lung cancer was of the adenocarcinoma type (68.7%). The diagnosis was late (stage IV) in 62.4% of cases. BPC was metastatic to bone (52%), contralateral lung (25.9%), and brain (27.3%). Patients were oligometastatic in 26% of cases. Surgery and radiotherapy were performed respectively in 14.5% and 23.1% of cases. Three-quarters of the patients had had nutrition (75.2%). The ROS1 mutation was present in 1 patient. PDL-1 expression was >40% in 2 patients. Survival was mean eight months ± 7.4. Conclusion: Lung cancer is diagnosed at a late stage in Tunisia. The lack of molecular study for non-small cell PBC and the lack of marketing authorization for tyrosine kinase inhibitors in Tunisia make the management incomplete.

Keywords: SCLC, NCSLC, ROS1, PDL1

Procedia PDF Downloads 79

Authors: Mohammad Heidari

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In this paper a method for high strength steel is proposed of residual stresses in autofrettaged tubes by combination of artificial neural networks is presented. Many different thick walled cylinders that were subjected to different conditions were studied. At first, the residual stress is calculated by analytical solution. Then by changing of the parameters that influenced in residual stresses such as percentage of autofrettage, internal pressure, wall ratio of cylinder, material property of cylinder, bauschinger and hardening effect factor, a neural network is created. These parameters are the input of network. The output of network is residual stress. Numerical data, employed for training the network and capabilities of the model in predicting the residual stress has been verified. The output obtained from neural network model is compared with numerical results, and the amount of relative error has been calculated. Based on this verification error, it is shown that the radial basis function of neural network has the average error of 2.75% in predicting residual stress of thick wall cylinder. Further analysis of residual stress of thick wall cylinder under different input conditions has been investigated and comparison results of modeling with numerical considerations shows a good agreement, which also proves the feasibility and effectiveness of the adopted approach.

Keywords: thick walled cylinder, residual stress, radial basis, artificial neural network

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Authors: G. Disciglio, G. Gatta, A. Libutti, A. Tarantino, L. Frabboni, E. Tarantino

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Results of a field study carried out at Trinitapoli (Puglia region, southern Italy) on the irrigation of an artichoke crop with three types of water (secondary-treated wastewater, SW; tertiary-treated wastewater, TW; and freshwater, FW) are reported. Physical, chemical and microbiological analyses were performed on the irrigation water, and on soil and yield samples. The levels of most of the chemical parameters, such as electrical conductivity, total suspended solids, Na+, Ca2+, Mg+2, K+, sodium adsorption ratio, chemical oxygen demand, biological oxygen demand over 5 days, NO3 –N, total N, CO32, HCO3, phenols and chlorides of the applied irrigation water were significantly higher in SW compared to GW and TW. No differences were found for Mg2+, PO4-P, K+ only between SW and TW. Although the chemical parameters of the three irrigation water sources were different, few effects on the soil were observed. Even though monitoring of Escherichia coli showed high SW levels, which were above the limits allowed under Italian law (DM 152/2006), contamination of the soil and the marketable yield were never observed. Moreover, no Salmonella spp. were detected in these irrigation waters; consequently, they were absent in the plants. Finally, the data on the quantitative-qualitative parameters of the artichoke yield with the various treatments show no significant differences between the three irrigation water sources. Therefore, if adequately treated, municipal wastewater can be used for irrigation and represents a sound alternative to conventional water resources.

Keywords: artichoke, soil chemical characteristics, fecal indicators, treated municipal wastewater, water recycling

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Authors: Arvan Prakash Ankitha, Madasamy Arockiasamy

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The increasing demand for adopting pile foundations in bridgeshas pointed towardsthe need to constantly improve the existing analytical techniques for better understanding of the behavior of such foundation systems. This study presents a simplistic approach using the energy-based method to assess the displacement responses of piles subjected to general loading conditions: Axial Load, Lateral Load, and a Bending Moment. The governing differential equations and the boundary conditions for a bridge pile embedded in multi-layered soil strata subjected to the general loading conditions are obtained using the Hamilton’s principle employing variational principles and minimization of energies. The soil non-linearity has been incorporated through simple constitutive relationships that account for degradation of soil moduli with increasing strain values.A simple power law based on published literature is used where the soil is assumed to be nonlinear-elastic and perfectly plastic. A Tresca yield surface is assumed to develop the soil stiffness variation with different strain levels that defines the non-linearity of the soil strata. This numerical technique has been applied to a pile foundation in a two - layered soil strata for a pier supporting the bridge and solved using the software MATLAB R2019a. The analysis yields the bridge pile displacements at any depth along the length of the pile. The results of the analysis are in good agreement with the published field data and the three-dimensional finite element analysis results performed using the software ANSYS 2019R3. The methodology can be extended to study the response of the multi-strata soil supporting group piles underneath the bridge piers.

Keywords: pile foundations, deep foundations, multilayer soil strata, energy based method

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Authors: Mannal Tariq

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Construction industry is making progress at a high pace. The trend of the world is getting more biased towards the high rise buildings. Deep beams are one of the most common elements in modern construction having small span to depth ratio. Deep beams are mostly used as transfer girders. This experimental study consists of 16 reinforced concrete (RC) deep beams. These beams were divided into two groups; A and B. Groups A and B consist of eight beams each, having 381 mm (15 in) and 457 mm (18 in) depth respectively. Each group was further subdivided into four sub groups each consisting of two identical beams. Each subgroup was comprised of solid/control beam (without opening), opening above neutral axis (NA), at NA and below NA. Except for control beams, all beams with openings were strengthened with carbon fibre reinforced polymer (CFRP) vertical strips. These eight groups differ from each other based on depth and location of openings. For testing sake, all beams have been loaded with two symmetrical point loads. All beams have been designed based on strut and tie model concept. The outcome of experimental investigation elaborates the difference in the shear behaviour of deep beams based on depth and location of circular openings variation. 457 mm (18 in) deep beam with openings above NA show the highest strength and 381 mm (15 in) deep beam with openings below NA show the least strength. CFRP sheets played a vital role in increasing the shear capacity of beams.

Keywords: CFRP, deep beams, openings in deep beams, strut and tie modal, shear behaviour

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Authors: Monalisha Nayak, T. G. Sitharam

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Liquefaction is a major threat for sites consists of or on sandy soil. But this present study concentrates on the behavior of fine soil under cyclic loading. This paper presents the study of liquefaction susceptibility of marine silty clay to clayey silt for an offshore site near western Yemen. The submerged and loose sediment condition of marine soil of an offshore site can favour liquefaction during earthquakes. In this regard, the liquefaction susceptibility of the site was carried out based on both field test results and laboratory test results. From field test results of seismic cone penetration test (SCPT), liquefaction susceptibility was assessed considering normalized cone tip resistance, and normalized friction ratio and results give an idea regarding both cyclic mobility and flow liquefaction. Laboratory cyclic triaxial tests were also conducted on saturated undisturbed and remoulded sample to study the effect of cyclic loading on strength and strain characteristics. Liquefaction susceptibility of the marine soft soil was also carried out based on index properties like grain size distribution, natural moisture content and liquid limit of soil.

Keywords: index properties, liquefaction, marine soil, seismic cone penetration test (SCPT)

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Authors: Abdallah M. Abdelkawy, Tarek M. El Hossainya, I. El Mahallawib

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Recently, significant achievements have been made in development and manufacturing of nano-dispersed metal matrix nanocomposites (MMNCs). They gain their importance due to their high strength to weight ratio. The machining problems of these new materials are less widely investigated, thus this work focuses on machining of them. Aluminum-Silicon (A356)/ MMNC dispersed with alumina (Al2O3) is important in many applications include engine blocks. The final finish process of this application depends heavily on machining. The most important machining parameter studied includes: cutting force and surface roughness. Experimental trails are performed on the number of special samples of MMNC (with different Al2O3%) where the relation between Al2O3% and cutting speed, feed rate and cutting depth with cutting force and surface roughness were studied. The data obtained were statistically analyzed using Analysis of variance (ANOVA) to define the significant factors on both cutting force and surface roughness and their level of confident. Response Surface Methodology (RSM) is used to build a model relating cutting conditions and Al2O3% to the cutting force and surface roughness. The results have shown that feed and depth of cut have the major contribution on the cutting force and the surface roughness followed by cutting speed and nano-percent in MMNCs.

Keywords: machinability, cutting force, surface roughness, Ra, RSM, ANOVA, MMNCs

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Authors: Yogi Wibisono Budhi, Ferry Iskandar, Veinardi Suendo, Muhammad Fakhrudin, Neng Tresna Umi Culsum

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Oil palm empty fruit bunch (OPEFB), an abundant agro-waste in Indonesia, is being studied as raw material of Cellulose Nanocrystals (CNC) synthesis. Instead of conventional acid mineral, phosphotungstic acid (H₃PW₁₂O₄₀, HPW) was used to hydrolyze cellulose due to recycling ability and easy handling. Before hydrolysis process, dried EFB was treated by 4% NaOH solution at 90oC for 2 hours and then bleached using 2% NaClO₂ solution at 80oC for 3 hours to remove hemicellulose and lignin. Hydrolysis reaction parameters such as temperature, acid concentration, and reaction time were optimized with fixed solid-liquid ratio of 1:40. Response surface method was used for experimental design to determine the optimum condition of each parameter. HPW was extracted from the mixed solution and recycled with diethyl ether. CNC was separated from the solution by centrifuging and washing with distilled water and ethanol to remove degraded sugars and unreacted celluloses. In this study, pulp from dried EFB produced 44.8% yield of CNC. Dynamic Light Scattering (DLS) analysis showed that most of CNC equivalent diameter was 140 nm. Crystallinity index was observed at 73.3% using X-ray Diffraction (XRD) analysis. Thus, a green established process for the preparation of CNC was achieved.

Keywords: acid hydrolysis, cellulose nanocrystals, oil palm empty fruit bunch, phosphotungstic acid

Procedia PDF Downloads 217

Authors: Behrang Ekrami, Amin Tamadon, Iman Razeghian Jahromi, Darioush Moghadas, Mehdi Ghahremani-Seno, Mostafa Ghaderi-Zefrehei, Ahmad Sodagar Amiri, Taheri Reza

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Persian fallow deer (Dama dama mesopotamica) is belonging to the family Cervidae and is only found in a few protected areas in the northwest, north, and southwest of Iran. The aims of this study were analysis of inbreeding and morphometric parameters of semen in male Persian fallow deer to investigate the cause of reduced fertility of this endangered species in Dasht-e-Naz National Refuge, Sari, Iran. The Persian fallow deer semen was collected from four adult bucks randomly during the breeding and non-breeding season from five dehorned and horned deer's by an artificial vagina. Twelve blood samples was taken from Persian fallow deer and mitochondrial DNA was extracted, amplified, extracted, sequenced and then were considered for genetic analysis. The Persian fallow deer semen, both with normal and abnormal spermatozoa, is similar to that of domestic ruminants but very smaller and difficult to observe at the primary observation. The post-mating season collected ejaculates contained abnormal spermatozoa, debris and secretion of accessory glands in horned bucks and accessory glands secretion free of any spermatozoa in dehorned or early velvet budding bucks. Microscopic evaluation in all four bucks during the mating season showed the mean concentration of 9×106 spermatozoa/ml. The mean ± SD of age, testes length and testes width was 4.60 ± 1.52 years, 3.58 ± 0.32 and 1.86 ± 0.09 cm, respectively. The results identified 1120 loci (assuming each nucleotide as locus) in which 377 were polymorphic. In conclusion, reduced fertility of male Persian fallow deer may be caused by inbreeding of the protected herd in a limited area of Dasht-e-Naz National Refuge.

Keywords: Persian fallow deer, genetic analysis, spermatozoa, reproductive characteristics

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Authors: Maomao Cao

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Background and aims While the association between higher consumption of fish and lower liver cancer risk has been confirmed, however, the association between specific fish intake and liver cancer risk remains unknown. We aimed to identify the association between specific fish consumption and the risk of liver cancer. Methods: Based on a community-based seropositive hepatitis B cohort involving 18404 individuals, face to face interview was conducted by a standardized questionnaire to acquire baseline information. Three common fish types in this study were analyzed, including freshwater fish, sea fish, and small fish (shrimp, crab, conch, and shell). All participants received liver cancer screening, and possible cases were identified by CT or MRI. Multivariable logistic models were applied to estimate the odds ratio (OR) and 95% confidence intervals (CI). Multivariate multiple imputations were utilized to impute observations with missing values. Results: 179 liver cancer cases were identified. Consumption of freshwater fish and sea fish at least once a week had a strong inverse association with liver cancer risk compared with the lowest intake level, with an adjusted OR of 0.53 (95% CI, 0.38-0.75) and 0.38 (95% CI, 0.19-0.73), respectively. This inverse association was also observed after the imputation. There was no statistically significant association between intake of small fish and liver cancer risk (OR=0.58, 95%, CI 0.32-1.08). Conclusions: Our findings suggest that consumption of freshwater fish and sea fish at least once a week could reduce liver cancer risk.

Keywords: cross-sectional study, fish intake, liver cancer, risk factor

Procedia PDF Downloads 273

Authors: Orapan Paecharoenchai, Tanasait Ngawhirunpat, Theerasak Rojanarata, Auayporn Apirakaramwong, Praneet Opanasopit

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Cationic niosomes formulated with Span20, cholesterol and novel synthesized spermine-cationic lipids (2-hydrocarbon tail and 4- hydrocarbon tail) in a molar ratio of 2.5:2.5:1 can mediate high gene transfection in vitro. However, the uptake mechanisms of these systems are not well clarified. In the present study, effect of endocytic inhibitors on the transfection efficiency of niosomes/DNA complexes was determined on a human cervical carcinoma cell line (HeLa cells) using the inhibitors of macropinocytosis (wortmannin), clathrin- and caveolae-mediated endocytosis (methyl-β-cyclodextrin), clathrin-mediated endocytosis (chlorpromazine), caveolae-mediated endocytosis (genistein and filipin), cytosolic transfer (ammonium chloride) and microtubules polymerization (nocodazole). The transfection of niosomes with 2-hydrocarbon tail lipid was blocked by nocodazole, genistein, ammonium chloride and filipin, respectively, whereas, the transfection of niosomes with 4-hydrocarbon tail lipid was blocked by nocodazole, genistein, ammonium chloride, methyl-β-cyclodextrin and filipin, respectively. It can be concluded that these niosomes/DNA complexes were internalized predominantly by endocytosis via clathrin and caveolae-independent pathway.

Keywords: cellular internalization, cationic niosomes, gene carriers, spermine-cationic lipids

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Authors: Rawan Aljabbari, Thamer Alomayri, Faisal G. Al-Maqate, Abeer Al Suwat

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For environmentally friendly innovative technologies and a sustainable future, fly ash/TiO₂ thin film nanocomposites are essential. Fly ash will be doped with titanium dioxide in this work in order to better understand its optical characteristics and employ it in semiconductor electrical devices. This study focused on the structure, morphology, and optical properties of fly ash/TiO₂ thin films. The spin-coating technique was used to create thin coatings of fly ash/TiO₂. For the first time, the doping of TiO₂ in the fly ash host at ratios of 1, 2, and 3 wt% was investigated with the thickness of all samples fixed. When compared to undoped thin films, the surface morphology of the doped thin films was improved. The weakly crystalline structure of the doped fly ash films was verified by XRD. The optical bandgap energy of these films was successfully reduced by the TiO₂ doping, going from 3.9 to 3.5 eV. With increasing dopant concentration, the value of Urbach energy is increasing. The optical band gap is clearly in opposition to the disorder. While it considerably improved the optical conductivity to a value of 4.1 x 10^9 s^(-1), it also raised the refractive index and extinction coefficient. Depending on the TiO₂ doping ratio, the transmittance decreased, and the reflection increased. As the TiO₂ concentration rises, the absorption of photon energy rises, and the absorption coefficient of photon energy is reduced. results in their possible use as solar energy and semiconductor materials.

Keywords: fly ash, structural analysis, optical properties, morphology

Procedia PDF Downloads 86

Authors: Ibrahim Mohammed

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Background: Diabetes mellitus is a chronic disease that can cause devastating secondary complications, reducing the quality and length of life as well as increasing medical costs for the patient and society. The guidelines recommend both clinical and preventive strategies for diabetes management and are regularly updated. The aim of the study is to assess the level of adherence of physicians to American Diabetes Association Guidelines. Method: Observational multicenter retrospective study will be conducted among different hospitals in the central region. Patient data will be collected from the records of the last three years (2017- 2020). Records will be selected randomly after a complete randomized design. The study focuses on the management of type 2 according to ADA not changed in the last three updating; those standards; all patients should be taking Metformin 1500 to 2000 mg/day as recommended dose and should be received a high dose of statin if the high risk to ASCVD or moderate statin if not at risk, patients with hypertension and diabetes should taking ACE or ARBS. Result: The study aimed to evaluate the commitment of physicians in the central region to the ADA. Out of the 153 selected patients, only 17 % were able to control their diabetes with an average A1c below 7. ADA stated that to reach the minimum benefit of using Metformin, the daily dose should be between 1500 and 2000 mg. Results showed that 110 patients were on Metformin, where 68% of them were on the recommended dose. ADA recommended the intake of high statin for diabetic patients with ASCVD risk, while diabetic patients without ASCVD risk should be on a moderate statin. Results showed that 61.5% of patients with ASCVD risk were at high statin while only 36% of patients without ASCVD risk were at moderate statin. Results showed that 89 patients have hypertension, and 80% of them are getting ACE/ARBs as recommended by the ADA. Recommendation: It is necessary to implement periodic training courses for some physicians to enhance and update their knowledge.

Keywords: American Diabetic Association, diabetes mellitus, atherosclerotic cardiovascular disease, ACE inhibitors

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Authors: Mohsen Torabi, Nader Karimi, Kaili Zhang

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This work aims to provide a comprehensive study on the heat transfer and entropy generation rates of a horizontal channel partially filled with a porous medium which experiences internal heat generation or consumption due to exothermic or endothermic chemical reaction. The focus has been given to the local thermal non-equilibrium (LTNE) model. The LTNE approach helps us to deliver more accurate data regarding temperature distribution within the system and accordingly to provide more accurate Nusselt number and entropy generation rates. Darcy-Brinkman model is used for the momentum equations, and constant heat flux is assumed for boundary conditions for both upper and lower surfaces. Analytical solutions have been provided for both velocity and temperature fields. By incorporating the investigated velocity and temperature formulas into the provided fundamental equations for the entropy generation, both local and total entropy generation rates are plotted for a number of cases. Bifurcation phenomena regarding temperature distribution and interface heat flux ratio are observed. It has been found that the exothermicity or endothermicity characteristic of the channel does have a considerable impact on the temperature fields and entropy generation rates.

Keywords: entropy generation, exothermicity or endothermicity, forced convection, local thermal non-equilibrium, analytical modelling

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Authors: Adham M. Salah, Tariq A. Nagem, Raed A. Abd-Alhameed, James M. Noras

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Recently, the demand for wireless communications systems to cover more than one frequency band (multi-band) with high data rate has been increased for both fixed and mobile services. Multiple Input Multiple Output (MIMO) technology is one of the significant solutions for attaining these requirements and to achieve the maximum channel capacity of the wireless communications systems. The main issue associated with MIMO antennas especially in portable devices is the compact space between the radiating elements which leads to limit the physical separation between them. This issue exacerbates the performance of the MIMO antennas by increasing the mutual coupling between the radiating elements. In other words, the mutual coupling will be stronger if the radiating elements of the MIMO antenna are closer. This paper presents a low–profile dual-band (2×1) MIMO antenna that works at 2.4GHz, 5.3GHz and 5.8GHz for wireless local area networks (WLAN) applications. A neutralization line (NL) technique for enhancing the isolation has been used by introducing a strip line with a length of λg/4 at the isolation frequency (2.4GHz) between the radiating elements. The overall dimensions of the antenna are 33.5 x 36 x 1.6 mm³. The fabricated prototype shows a good agreement between the simulated and measured results. The antenna impedance bandwidths are 2.38–2.75 GHz and 4.4–6 GHz for the lower and upper band respectively; the reflection coefficient and mutual coupling are better than -25 dB in both lower and higher bands. The MIMO antenna performance characteristics are reported in terms of the scattering parameters, envelope correlation coefficient (ECC), total active reflection coefficient, capacity loss, antenna gain, and radiation patterns. Analysis of these characteristics indicates that the design is appropriate for the WLAN terminal applications.

Keywords: ECC, neutralization line, MIMO antenna, multi-band, mutual coupling, WLAN

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Authors: Nicolò Vaiana, Mariacristina Spizzuoco, Giorgio Serino

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In this paper, the results of experimental tests performed on a Helical Wire Rope Isolator (HWRI) are presented in order to describe the dynamic and static behavior of the selected metal device in three different displacements ranges, namely small, relatively large, and large displacements ranges, without and under the effect of a vertical load. A testing machine, allowing to apply horizontal displacement or load histories to the tested bearing with a constant vertical load, has been adopted to perform the dynamic and static tests. According to the experimental results, the dynamic behavior of the tested device depends on the applied displacement amplitude. Indeed, the HWRI displays a softening and a hardening stiffness at small and relatively large displacements, respectively, and a stronger nonlinear stiffening behavior at large displacements. Furthermore, the experimental tests reveal that the application of a vertical load allows to have a more flexible device with higher damping properties and that the applied vertical load affects much less the dynamic response of the metal device at large displacements. Finally, a decrease in the static to dynamic effective stiffness ratio with increasing displacement amplitude has been observed.

Keywords: base isolation, earthquake engineering, experimental hysteresis loops, wire rope isolators

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Authors: Taylan Ozturk, Osama Maklad

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This study examines the aerodynamic and flow properties of a multi-element airfoil using computational fluid dynamics (CFD) research. This computational analysis aims to optimize slat design concerning lift-drag coefficients and to determine the ideal gap size between the main airfoil and the front flap. It examines the influence of varying angles of attack and the effects of varied Reynolds numbers. A NACA 2412 airfoil, equipped with custom-designed front and rear flaps, was modeled in SolidWorks and simulated in ANSYS Fluent utilizing the k-ω SST turbulence model. This study quantifies lift and drag coefficients, turbulent kinetic energy, and vorticity magnitude across various configurations. The results clearly indicate that the slat-optimized design geometry featuring a 4 mm gap provides the best performance regarding both lift and drag, with maximum efficiency achieved at a 4-degree angle of attack. Furthermore, the results indicate the initiation of stall conditions beyond 20 degrees and demonstrate how an increase in Reynolds numbers influences flow separation and turbulence patterns. In addition, the maximum L/D ratio which is 36.18 achieved. These findings enhance the comprehension of multi-element airfoil behavior, directly impacting aircraft design and operation, particularly in high-lift situations.

Keywords: multi-element airfoil, CFD simulation, aerodynamic characteristics, Reynolds number analysis

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Authors: Anas El Amraoui, Abdelkhalek Cheddadi, Mohammed Touhami Ouazzani

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Laminar natural convection in a cylindrical annular cavity filled with air and provided with two fins is studied numerically using the discretization of the governing equations with the Centered Finite Difference method based on the Alternating Direction Implicit (ADI) scheme. The fins are attached to the inner cylinder of radius r_i (hot wall of temperature T_i). The outer cylinder of radius r_o is maintained at a temperature T_o (T_o < T_i). Two values of the dimensionless thickness of the fins are considered: 0.015 and 0.203. We consider a low fin height equal to 0.078 and medium fin heights equal to 0.093 and 0.203. The position of the fin is 0.82π and the radius ratio is equal to 2. The effect of Rayleigh number, Ra, on the flow structure and heat transfer is analyzed for a range of Ra from 10³ to 10⁴. The results for established flow structures and heat transfer at low height indicate that the flow regime that occurs is unicellular for all Ra and fin thickness; in addition, the heat transfer rate increases with increasing Rayleigh number and is the same for both thicknesses. At median fin heights 0.093 and 0.203, the increase of Rayleigh number leads to transitions of flow structure which correspond to significant variations of the heat transfer. The critical Rayleigh numbers, Ra_c.app and Ra_c.disp corresponding to the appearance of the bicellular flow regime and its disappearance, are determined and their influence on the change of heat transfer rate is analyzed.

Keywords: natural convection, fins, critical Rayleigh number, heat transfer, fluid flow regime, horizontal annulus

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Authors: Muhammed Ordu, Eren Demir, Chris Tofallis

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The number of inpatient admissions in the UK has been significantly increasing over the past decade. These increases cause bed occupancy rates to exceed the target level (85%) set by the Department of Health in England. Therefore, hospital service managers are struggling to better manage key resource such as beds. On the other hand, this severe demand pressure might lead to confusion in wards. For example, patients can be admitted to the ward of another inpatient specialty due to lack of resources (i.e., bed). This study aims to develop a simulation-optimization model to reallocate the available number of beds in a mid-sized hospital in the UK. A hospital simulation model was developed to capture the stochastic behaviours of the hospital by taking into account the accident and emergency department, all outpatient and inpatient services, and the interactions between each other. A couple of outputs of the simulation model (e.g., average length of stay and revenue) were generated as inputs to be used in the optimization model. An integer linear programming was developed under a number of constraints (financial, demand, target level of bed occupancy rate and staffing level) with the aims of maximizing number of admitted patients. In addition, a sensitivity analysis was carried out by taking into account unexpected increases on inpatient demand over the next 12 months. As a result, the major findings of the approach proposed in this study optimally reallocate the available number of beds for each inpatient speciality and reveal that 74 beds are idle. In addition, the findings of the study indicate that the hospital wards will be able to cope with 14% demand increase at most in the projected year. In conclusion, this paper sheds a new light on how best to reallocate beds in order to cope with current and future demand for healthcare services.

Keywords: bed occupancy rate, bed reallocation, discrete event simulation, inpatient admissions, integer linear programming, projected usage

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Authors: Rajneesh, Priyanka Singh

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Biomass resources have been one of the main energy sources for mankind since the dawn of civilization. There is a vast scope to convert these energy sources into biogas which is a clean, low carbon technology for efficient management and conversion of fermentable organic wastes into a cheap and versatile fuel and bio/organic manure. Thus, in order to enhance the performance of anaerobic digester, an optimizing analysis of resultant parameters (organic dry matter (oDM) content, methane percentage, and biogas yield) has been done for a plug flow anaerobic digester having mesophilic conditions (20-40°C) with the wet fermentation process. Based on the analysis, correlations for oDM, methane percentage, and biogas yield are derived using multiple regression analysis. A statistical model is developed to correlate the operating variables using the design of experiment approach by selecting central composite design (CCD) of a response surface methodology. Results shown in the paper indicates that as the operating temperature increases the efficiency of digester gets improved provided that the pH and hydraulic retention time (HRT) remains constant. Working in an optimized range of carbon-nitrogen ratio for the plug flow digester, the output parameters show a positive change with the variation of dry matter content (DM).

Keywords: biogas, digester efficiency, design of experiment, plug flow digester

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Authors: K. R. Sreenivas, Shaurya Kaushal

Abstract:

After sunset, under calm & clear-sky nocturnal conditions, the air layer near the surface containing aerosols cools through radiative processes to the upper atmosphere. Due to this cooling, surface air-layer temperature can fall 2-6 degrees C lower than the ground-surface temperature. This unstable convection layer, on the top, is capped by a stable inversion-boundary layer. Radiative divergence, along with the convection within the surface layer, governs the vertical transport of heat and moisture. Micro-physics in this layer have implications for the occurrence and growth of the fog layer. This particular configuration, featuring a convective mixed layer beneath a stably stratified inversion layer, exemplifies a classic case of penetrative convection. In this study, we conduct numerical simulations of the penetrative convection phenomenon within the nocturnal atmospheric surface layer and elucidate its relevance to the dynamics of fog layers. We employ field and laboratory measurements of aerosol number density to model the strength of the radiative cooling. Our analysis encompasses horizontally averaged, vertical profiles of temperature, density, and heat flux. The energetic incursion of the air from the mixed layer into the stable inversion layer across the interface results in entrainment and the growth of the mixed layer, modeling of which is the key focus of our investigation. In our research, we ascertain the appropriate length scale to employ in the Richardson number correlation, which allows us to estimate the entrainment rate and model the growth of the mixed layer. Our analysis of the mixed layer and the entrainment zone reveals a close alignment with previously reported laboratory experiments on penetrative convection. Additionally, we demonstrate how aerosol number density influences the growth or decay of the mixed layer. Furthermore, our study suggests that the presence of fog near the ground surface can induce extensive vertical mixing, a phenomenon observed in field experiments.

Keywords: inversion layer, penetrative convection, radiative cooling, fog occurrence

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Authors: Hasan Dalgic, Fikret Akinerdem

Abstract:

This trial was made to determine effect of different plant density and weed control on yield and quality of winter sowing safflower (Carthamus tinctorius L.) in Selcuk University, Agricultural Faculty trial fields and the effective substance of Trifluran was used as herbicide. Field trial was made during the vegetation period of 2009-2010 with three replications according to 'Split Plots in Randomized Blocks' design. The weed control techniques were made on main plots and row distances was set up on sub-plots. The trial subjects were consisting from three weed control techniques as fallowing: herbicide application (Trifluran), hoeing and control beside the row distances of 15 cm and 30 cm. The results were ranged between 59.0-76.73 cm in plant height, 40.00-47.07 cm in first branch height, 5.00-7.20 in number of branch per plant, 6.00-14.73 number of head per plant, 19.57-21.87 mm in head diameter, 2125.0-3968.3 kg ha-1 in seed yield, 27.10-28.08 % in crude oil rate and 531.7-1070.3 kg ha-1. According to the results, Remzibey safflower cultivar showed the highest seed yield on 30 cm of row distance and herbicide application by means of the direct effects of plant height, first branch height, number of branch per plant, number of head per plant, table diameter, crude oil rate and crude oil yield.

Keywords: safflower, herbicide, row spacing, seed yield, oil ratio, oil yield

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Authors: Mimoza Canga, Vito Malagnino, Giulia Malagnino, Irene Malagnino

Abstract:

Objective: The objective of this study was to compare the effectiveness of Mtwo and RaCe rotary instruments, in cleaning and shaping root canals curvature. Material and Method: The present study was conducted on 160 simulated canals in resin blocks, with an angle curvature 15°-30°. These 160 simulated canals were divided into two groups, where each group consisted of 80 blocks. Each group was divided into two subgroups (n=40 canals each). The simulated canals subgroups were prepared with Mtwo and RaCe rotary nickel-titanium instruments. The root canals were measured at four different points of reference, starting at 13 mm from the orifice. In the first group, the canals were prepared using Mtwo rotary system (VDW, Munich, Germany). The Mtwo files used were: 10/0.04, 15/0.05, 20/0.06, and 25/0.06. These instruments entered in the full length of the canal. Each file was rotated in the canal until it reached the apical point. In the second group, the canals were prepared using RaCe instruments (La Chaux-De-Fonds, Switzerland), performing the crown down technique, using the torque electric control motor (VDWCO, Munich, Germany), with 600 RPM and 2n/cm as follow: ≠40/0.10, ≠35/0.08, ≠30/0.06, ≠25/0.04, ≠25/0.02. The data were recorded using SPSS version 23 software (Microsoft, IL, USA). Data analysis was done using ANOVA test. Results: The results obtained by using the Mtwo rotary instruments, showed that these instruments were able to clean and shape in the right-to-left motion curved canals, at different levels, without any deviation, and in perfect symmetry, with a P-value=0.000. The data showed that the greater the depth of the root canal, the greater the deviations of the RaCe rotary instruments. These deviations occurred in three levels, which are: S2(P=0.004), S3( P=0.007), S4(P=0.009). The Mtwo files can go deeper and create a greater angle in S4 level (21°-28°), compared to RaCe instruments with an angle equal to 19°-24°. Conclusion: The present study noted a clinically significant difference between Mtwo rotary instruments and RaCe rotary files used for the canal preparation and indicated that Mtwo instruments are a better choice for the curved canals.

Keywords: canal curvature, canal preparation, Mtwo, RaCe, resin blocks

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Authors: Mohammed Tahir, Jonas Lagergren

Abstract:

Vancron 40, a nitrided powder metallurgical tool Steel, is used in cold work applications where the predominant failure mechanisms are adhesive wear or galling. Typical applications of Vancron 40 are among others fine blanking, cold extrusion, deep drawing and cold work rolls for cluster mills. Vancron 40 positive results for cold work rolls for cluster mills and as a tool for some severe metal forming process makes it competitive compared to other type of work rolls that require higher precision, among others in cold rolling of thin stainless steel, which required high surface finish quality. In this project, three roll materials for cold rolling of stainless steel strip was examined, Vancron 40, Narva 12B (a high-carbon, high-chromium tool steel alloyed with tungsten) and Supra 3 (a Chromium-molybdenum tungsten-vanadium alloyed high speed steel). The purpose of this project was to study the depth profiles of the ironed stainless steel strips, emergence of galling and to study the lubrication performance used by steel industries. Laboratory experiments were conducted to examine scratch of the strip, galling and surface roughness of the roll materials under severe tribological conditions. The critical sliding length for onset of galling was estimated for stainless steel with four different lubricants. Laboratory experiments result of performance evaluation of resistance capability of rolls toward adhesive wear under severe conditions for low and high reductions. Vancron 40 in combination with cold rolling lubricant gave good surface quality, prevents galling of metal surfaces and good bearing capacity.

Keywords: Vancron 40, cold rolling, adhesive wear, galling, surface finish, lubricant, stainless steel

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Authors: Linet Melisa Daubanes, Nhleko Monique Chiloane

Abstract:

The shovel-truck system is the most prevalent material handling system used in surface mining operations. Material handling entails the loading and hauling of material from production areas to dumping areas. The material handling process has operational delays that have a negative impact on the productivity of the load and haul fleet. Factors that may contribute to operational delays include shovel-truck mismatch, haul routes, machine breakdowns, extreme weather conditions, etc. The aim of this paper is to investigate factors that contribute to operational delays affecting the productivity of the load and haul fleet at the mine. Productivity is the measure of the effectiveness of producing products from a given quantity of units, the ratio of output to inputs. Productivity can be improved by producing more outputs with the same or fewer units and/or introducing better working methods etc. Several key performance indicators (KPI) for the evaluation of productivity will be discussed in this study. These KPIs include but are not limited to hauling conditions, bucket fill factor, cycle time, and utilization. The research methodology of this study is a combination of on-site time studies and observations. Productivity can be optimized by managing the factors that affect the operational performance of the haulage fleet.

Keywords: cycle time, fleet performance, load and haul, surface mining

Procedia PDF Downloads 195

Authors: M. Borgie, Z. Dagher, F. Ledoux, A. Verdin, F. Cazier, H. Greige, P. Shirali, D. Courcot

Abstract:

In October 2013, the International Agency for Research on Cancer (IARC) classified outdoor air pollution and fine particulate matter (PM2.5) as carcinogenic to humans. Despite the clearly relationship established by epidemiological studies between PM exposure and the onset of respiratory and cardiovascular diseases, uncertainties remain about the physiopathological mechanisms responsible for these diseases. The aim of this work was to evaluate the toxicological effects of two samples of atmospheric PM2.5 collected at urban and rural sites on human bronchial epithelial cells, BEAS-2B, especially to investigate the metabolic activation of organic compounds, the alteration of epigenetic mechanisms (i.e. microRNAs genes expression), the phosphorylation of H2AX and the telomerase activity. Our results showed a significant increase in CYP1A1, CYP1B1, and AhRR genes expression, miR-21 gene expression, H2AX phosphorylation and telomerase activity in BEAS-2B cells after their exposure to PM2.5, both in a dose and site-dependent manner. These results showed that PM2.5, especially urban PM, are able to induce the expression of metabolizing enzymes which can provide metabolic biotransformation of organic compounds into more toxic and carcinogenic metabolites, and to induce the expression of the oncomiR miR-21 which promotes cell growth and enhances tumor invasion and metastasis in lung cancer. In addition, our results have highlighted the role of PM2.5 in the activation of telomerase, which can maintain the telomeres length and subsequently preventing cell death, and have also demonstrated the ability of PM2.5 to induce DNA breaks and thus to increase the risk of mutations or chromosomal translocations that lead to genomic instability. All these factors may contribute to cell abnormalities, and thus the development of cancer.

Keywords: BEAS-2B cells, carcinogenesis, epigenetic alterations and genotoxicity, PM2.5

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Authors: P. Rahnemoon, M. Sarabi Jamab, M. Javanmard Dakheli, A. Bostan

Abstract:

In recent years, tendency to use of natural antimicrobial agents in food industry has increased. Pomegranate peels containing phenolic compounds and anti-microbial agents, are counted as valuable source for extraction of these compounds. In this study, the extraction of pomegranate peel extract was carried out at different ethanol/water ratios (40:60, 60:40, and 80:20), temperatures (25, 40, and 55 ˚C), and time durations (20, 24, and 28 h). The extraction yield, phenolic compounds, flavonoids, and anthocyanins were measured. ‎Antimicrobial activity of pomegranate peel extracts were determined against some food-borne ‎microorganisms such as Salmonella enteritidis, Escherichia coli, Listeria monocytogenes, ‎‎Staphylococcus aureus, Aspergillus niger, and Saccharomyces cerevisiae by agar diffusion and MIC methods. Results showed that at ethanol/water ratio 60:40, 25 ˚C and 24 h maximum amount of phenolic compounds ‎‏(‎‏‎349.518‎‏ ‏mg gallic acid‏/‏g dried extract), ‎flavonoids (250.124 mg rutin‏/‏g dried extract), anthocyanins (252.047 ‎‏‏mg ‎cyanidin‏‎3‎‏glucoside‏/‏‎100 g dried extract), and the strongest antimicrobial activity were obtained. ‎All extracts’ antimicrobial activities were demonstrated against every tested ‎‎microorganisms‏.‎‏ Staphylococcus aureus showed the highest sensitivity among the tested ‎‎‎microorganisms.

Keywords: antimicrobial agents, phenolic compounds, pomegranate peel, solvent extraction‎

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Authors: Patcharakamon Nooeaid, Piyachat Chuysrinuan

Abstract:

Electrospun natural polymers-based nanofibers are one of the most interesting materials used in tissue engineering and drug delivery applications. Bead-on-string nanofibers have gained considerable interest for sustained drug release. Vancomycin was used as the model drug and sodium alginate (SA)/soy protein isolated (SPI) as the polymer blend to fabricate the bead-on-string nanofibers by aqueous-based electrospinning. The bead-on-string SA/SPI nanofibers were successfully fabricated by the addition of poly(ethylene oxide) (PEO) as a co-blending polymer. SA-PEO with mass ratio of 70/30 showed the best spinnability with continuous nanofibers without the occurrence of beads. Bead structure formed with the addition of SPI and bead number increased with increasing SPI content. The electrospinning of 80/20 SA-PEO/SPI was obtained as a great promising bead-on-string nanofibers for drug loading, while the solution of 50/50 was not able to obtain continuous fibers. In vitro release tests showed that a more sustainable release profile up to 14 days with less initial burst release on day 1 could be obtained from the bead-on-string fibers than from smooth fibers with uniform diameter. In addition, vancomycin-loaded beaded fibers inhibited the growth of Staphylococcus aureus (S. aureus) bacteria. Therefore, the SA-PEO/SPI nanofibers showed the potential to be used as biomaterials for tissue engineering and drug delivery.

Keywords: bead-on-string fibers, electrospinning, drug delivery, tissue engineering

Procedia PDF Downloads 334