Search results for: high protein and energy diet
Commenced in January 2007
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Edition: International
Paper Count: 26934

Search results for: high protein and energy diet

15084 Influence of Thermal Annealing on Phase Composition and Structure of Quartz-Sericite Minerale

Authors: Atabaev I. G., Fayziev Sh. A., Irmatova Sh. K.

Abstract:

Raw materials with high content of Kalium oxide widely used in ceramic technology for prevention or decreasing of deformation of ceramic goods during drying process and under thermal annealing. Becouse to low melting temperature it is also used to decreasing of the temperature of thermal annealing during fabrication of ceramic goods [1,2]. So called “Porceline or China stones” - quartz-sericite (muscovite) minerals is also can be used for prevention of deformation as the content of Kalium oxide in muscovite is rather high (SiO2, + KAl2[AlSi3O10](OH)2). [3] . To estimation of possibility of use of this mineral for ceramic manufacture, in the presented article the influence of thermal processing on phase and a chemical content of this raw material is investigated. As well as to other ceramic raw materials (kaoline, white burning clays) the basic requirements of the industry to quality of "a porcelain stone» are following: small size of particles, relative high uniformity of disrtribution of components and phase, white color after burning, small content of colorant oxides or chromophores (Fe2O3, FeO, TiO2, etc) [4,5]. In the presented work natural minerale from the Boynaksay deposit (Uzbekistan) is investigated. The samples was mechanically polished for investigation by Scanning Electron Microscope. Powder with size of particle up to 63 μm was used to X-ray diffractometry and chemical analysis. The annealing of samples was performed at 900, 1120, 1350oC during 1 hour. Chemical composition of Boynaksay raw material according to chemical analysis presented in the table 1. For comparison the composition of raw materials from Russia and USA are also presented. In the Boynaksay quartz – sericite the average parity of quartz and sericite makes 55-60 and 30-35 % accordingly. The distribution of quartz and sericite phases in raw material was investigated using electron probe scanning electronic microscope «JEOL» JXA-8800R. In the figure 1 the scanning electron microscope (SEM) micrograps of the surface and the distributions of Al, Si and K atoms in the sample are presented. As it seen small granular, white and dense mineral includes quartz, sericite and small content of impurity minerals. Basically, crystals of quartz have the sizes from 80 up to 500 μm. Between quartz crystals the sericite inclusions having a tablet form with radiant structure are located. The size of sericite crystals is ~ 40-250 μm. Using data on interplanar distance [6,7] and ASTM Powder X-ray Diffraction Data it is shown that natural «a porcelain stone» quartz – sericite consists the quartz SiO2, sericite (muscovite type) KAl2[AlSi3O10](OH)2 and kaolinite Al203SiO22Н2О (See Figure 2 and Table 2). As it seen in the figure 3 and table 3a after annealing at 900oC the quartz – sericite contains quartz – SiO2 and muscovite - KAl2[AlSi3O10](OH)2, the peaks related with Kaolinite are absent. After annealing at 1120oC the full disintegration of muscovite and formation of mullite phase Al203 SiO2 is observed (the weak peaks of mullite appears in fig 3b and table 3b). After annealing at 1350oC the samples contains crystal phase of quartz and mullite (figure 3c and table 3с). Well known Mullite gives to ceramics high density, abrasive and chemical stability. Thus the obtained experimental data on formation of various phases during thermal annealing can be used for development of fabrication technology of advanced materials. Conclusion: The influence of thermal annealing in the interval 900-1350oC on phase composition and structure of quartz-sericite minerale is investigated. It is shown that during annealing the phase content of raw material is changed. After annealing at 1350oC the samples contains crystal phase of quartz and mullite (which gives gives to ceramics high density, abrasive and chemical stability).

Keywords: quartz-sericite, kaolinite, mullite, thermal processing

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15083 Compact LWIR Borescope Sensor for Surface Temperature of Engine Components

Authors: Andy Zhang, Awnik Roy, Trevor B. Chen, Bibik Oleksandr, Subodh Adhikari, Paul S. Hsu

Abstract:

The durability of a combustor in gas-turbine enginesrequiresa good control of its component temperatures. Since the temperature of combustion gases frequently exceeds the melting point of the combustion liner walls, an efficient air-cooling system is significantly important to elongatethe lifetime of liner walls. To determine the effectiveness of the air-cooling system, accurate 2D surface temperature measurement of combustor liner walls is crucial for advanced engine development. Traditional diagnostic techniques for temperature measurement, such as thermocouples, thermal wall paints, pyrometry, and phosphors, have shown disadvantages, including being intrusive and affecting local flame/flow dynamics, potential flame quenching, and physical damages to instrumentation due to harsh environments inside the combustor and strong optical interference from strong combustion emission in UV-Mid IR wavelength. To overcome these drawbacks, a compact and small borescope long-wave-infrared (LWIR) sensor is developed to achieve two-dimensional high-spatial resolution, high-fidelity thermal imaging of 2D surface temperature in gas-turbine engines, providing the desired engine component temperature distribution. The compactLWIRborescope sensor makes it feasible to promote the durability of combustor in gas-turbine engines.

Keywords: borescope, engine, long-wave-infrared, sensor

Procedia PDF Downloads 118
15082 Simplified Analysis on Steel Frame Infill with FRP Composite Panel

Authors: HyunSu Seo, HoYoung Son, Sungjin Kim, WooYoung Jung

Abstract:

In order to understand the seismic behavior of steel frame structure with infill FRP composite panel, simple models for simulation on the steel frame with the panel systems were developed in this study. To achieve the simple design method of the steel framed structure with the damping panel system, 2-D finite element analysis with the springs and dashpots models was conducted in ABAQUS. Under various applied spring stiffness and dashpot coefficient, the expected hysteretic energy responses of the steel frame with damping panel systems we re investigated. Using the proposed simple design method which decides the stiffness and the damping, it is possible to decide the FRP and damping materials on a steel frame system.

Keywords: numerical analysis, FEM, infill, GFRP, damping

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15081 Amorphous Silicon-Based PINIP Structure for Human-Like Photosensor

Authors: Sheng-Chuan Hsu

Abstract:

Because the existing structure of ambient light sensor is most silicon photodiode device, it is extremely sensitive in the red and infrared regions. Even though the IR-Cut filter had added, it still cannot completely eliminate the influence of infrared light, and the spectral response of infrared light was stronger than that of the human eyes. Therefore, it is not able to present the vision spectrum of the human eye reacts with the ambient light. Then it needs to consider that the human eye feels the spectra that show significant differences between light and dark place. Consequently, in practical applications, we must create and develop advanced device of human-like photosensor which can solve these problems of ambient light sensor and let cognitive lighting system to provide suitable light to achieve the goals of vision spectrum of human eye and save energy.

Keywords: ambient light sensor, vision spectrum, cognitive lighting system, human eye

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15080 Binary Programming for Manufacturing Material and Manufacturing Process Selection Using Genetic Algorithms

Authors: Saleem Z. Ramadan

Abstract:

The material selection problem is concerned with the determination of the right material for a certain product to optimize certain performance indices in that product such as mass, energy density, and power-to-weight ratio. This paper is concerned about optimizing the selection of the manufacturing process along with the material used in the product under performance indices and availability constraints. In this paper, the material selection problem is formulated using binary programming and solved by genetic algorithm. The objective function of the model is to minimize the total manufacturing cost under performance indices and material and manufacturing process availability constraints.

Keywords: optimization, material selection, process selection, genetic algorithm

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15079 Carbon Nanotubes Functionalization via Ullmann-Type Reactions Yielding C-C, C-O and C-N Bonds

Authors: Anna Kolanowska, Anna Kuziel, Sławomir Boncel

Abstract:

Carbon nanotubes (CNTs) represent a combination of lightness and nanoscopic size with high tensile strength, excellent thermal and electrical conductivity. By now, CNTs have been used as a support in heterogeneous catalysis (CuCl anchored to pre-functionalized CNTs) in the Ullmann-type coupling with aryl halides toward formation of C-N and C-O bonds. The results indicated that the stability of the catalyst was much improved and the elaborated catalytic system was efficient and recyclable. However, CNTs have not been considered as the substrate itself in the Ullmann-type reactions. But if successful, this functionalization would open new areas of CNT chemistry leading to enhanced in-solvent/matrix nanotube individualization. The copper-catalyzed Ullmann-type reaction is an attractive method for the formation of carbon-heteroatom and carbon-carbon bonds in organic synthesis. This condensation reaction is usually conducted at temperature as high as 200 oC, often in the presence of stoichiometric amounts of copper reagent and with activated aryl halides. However, a small amount of organic additive (e.g. diamines, amino acids, diols, 1,10-phenanthroline) can be applied in order to increase the solubility and stability of copper catalyst, and at the same time to allow performing the reaction under mild conditions. The copper (pre-)catalyst is prepared by in situ mixing of copper salt and the appropriate chelator. Our research is focused on the application of Ullmann-type reaction for the covalent functionalization of CNTs. Firstly, CNTs were chlorinated by using iodine trichloride (ICl3) in carbon tetrachloride (CCl4). This method involves formation of several chemical species (ICl, Cl2 and I2Cl6), but the most reactive is the dimer. The fact (that the dimer is the main individual in CCl4) is the reason for high reactivity and possibly high functionalization levels of CNTs. This method, indeed, yielded a notable amount of chlorine onto the MWCNT surface. The next step was the reaction of CNT-Cl with three substrates: aniline, iodobenzene and phenol for the formation C-N, C-C and C-O bonds, respectively, in the presence of 1,10-phenanthroline and cesium carbonate (Cs2CO3) as a base. As the CNT substrates, two multi-wall CNT (MWCNT) types were used: commercially available Nanocyl NC7000™ (9.6 nm diameter, 1.5 µm length, 90% purity) and thicker MWCNTs (in-house) synthesized in our laboratory using catalytic chemical vapour deposition (c-CVD). In-house CNTs had diameter ranging between 60-70 nm and length up to 300 µm. Since classical Ullmann reaction was found as suffering from poor yields, we have investigated the effect of various solvents (toluene, acetonitrile, dimethyl sulfoxide and N,N-dimethylformamide) on the coupling of substrates. Owing to the fact that the aryl halides show the reactivity order of I>Br>Cl>F, we have also investigated the effect of iodine presence on CNT surface on reaction yield. In this case, in first step we have used iodine monochloride instead of iodine trichloride. Finally, we have used the optimized reaction conditions with p-bromophenol and 1,2,4-trihydroxybenzene for the control of CNT dispersion.

Keywords: carbon nanotubes, coupling reaction, functionalization, Ullmann reaction

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15078 Uptake of Hepatitis B Vaccine among Hepatitis C Positive Patients and Their Vaccine Response in Myanmar

Authors: Zaw Z Aung

Abstract:

Background: High-risk groups for hepatitis B infection (HBV) are people who injected drugs (PWID), men who have sex with men (MSM), people living with HIV (PLHIV) and persons with hepatitis C (HCV), etc. HBV/HCV coinfected patients are at increased risk of cirrhosis, hepatic decompensation and hepatocellular carcinoma. To the best of author’s knowledge, there is currently no data for hepatitis B vaccine utilization in HCV positive patients and their antibody response. Methodology: From February 2018 to May 2018, consented participants at or above 18 years who came to the clinic in Mandalay were tested with the anti-HCV rapid test. Those who tested HCV positive (n=168) were further tested with hepatitis B profile and asked about their previous hepatitis B vaccination history and risk factors. Results: Out of 168 HCV positive participants, three were excluded for active HBV infections. The remaining 165 were categorized into previously vaccinated 64% (n=106) and unvaccinated 36% (n=59) There were three characteristics groups- PWID monoinfected (n=77), General Population (GP) monoinfected (n=22) and HIV/HCV coinfected participants (n=66). Unvaccinated participants were highest in HIV/HCV, with 68%(n=45) followed by GP (23%, n=5) and PWID (12%, n=9). Among previously vaccinated participants, the highest percentage was PWID (88%, n=68), the second highest was GP (77%, n=17) and lowest in HIV/HCV patients (32%, n=21). 63 participants completed third doses of vaccination (PWID=36, GP=13, HIV/HCV=14). 53% of participants who completed 3 dose of hepatitis B were non-responders (n=34): HIV/HCV (86%, n=12), PWID (44%, n=16), and GP (46%, n=6) Conclusion: Even in the presence of effective and safe hepatitis B vaccine, uptake is low among high risk groups especially PLHIV that needs to be improved. Integration or collaboration of hepatitis B vaccination program, HIV/AIDS and hepatitis C treatment centers is desirable. About half of vaccinated participants were non-responders so that optimal doses, schedule and follow-up testing need to be addressed carefully for those groups.

Keywords: Hepatitis B vaccine, Hepatitis C, HIV, Myanmar

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15077 Integrated Power Saving for Multiple Relays and UEs in LTE-TDD

Authors: Chun-Chuan Yang, Jeng-Yueng Chen, Yi-Ting Mai, Chen-Ming Yang

Abstract:

In this paper, the design of integrated sleep scheduling for relay nodes and user equipments under a Donor eNB (DeNB) in the mode of Time Division Duplex (TDD) in LTE-A is presented. The idea of virtual time is proposed to deal with the discontinuous pattern of the available radio resource in TDD, and based on the estimation of the traffic load, three power saving schemes in the top-down strategy are presented. Associated mechanisms in each scheme including calculation of the virtual subframe capacity, the algorithm of integrated sleep scheduling, and the mapping mechanisms for the backhaul link and the access link are presented in the paper. Simulation study shows the advantage of the proposed schemes in energy saving over the standard DRX scheme.

Keywords: LTE-A, relay, TDD, power saving

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15076 Estimated Human Absorbed Dose of 111 In-BPAMD as a New Bone-Seeking Spect-Imaging Agent

Authors: H. Yousefnia, S. Zolghadri

Abstract:

An early diagnosis of bone metastases is very important for providing a profound decision on a subsequent therapy. A prerequisite for the clinical application of new diagnostic radiopharmaceutical is the measurement of organ radiation exposure dose from biodistribution data in animals. In this study, the dosimetric studies of a novel agent for SPECT-imaging of bone methastases, 111In-(4-{[(bis(phosphonomethyl))carbamoyl]methyl}-7,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl) acetic acid (111In-BPAMD) complex, have been estimated in human organs based on mice data. The radiolabeled complex was prepared with high radiochemical purity at the optimal conditions. Biodistribution studies of the complex were investigated in male Syrian mice at selected times after injection (2, 4, 24 and 48 h). The human absorbed dose estimation of the complex was performed based on mice data by the radiation absorbed dose assessment resource (RADAR) method. 111In-BPAMD complex was prepared with high radiochemical purity >95% (ITLC) and specific activities of 2.85 TBq/mmol. Total body effective absorbed dose for 111In-BPAMD was 0.205 mSv/MBq. This value is comparable to the other 111In clinically used complexes. The results show that the dose to critical organs the complex is well within the acceptable considered range for diagnostic nuclear medicine procedures. Generally, 111In-BPAMD has interesting characteristics and can be considered as a viable agent for SPECT-imaging of the bone metastases in the near future.

Keywords: In-111, BPAMD, absorbed dose, RADAR

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15075 Feasibility Study of Constructed Wetlands for Wastewater Treatment and Reuse in Asmara, Eritrea

Authors: Hagos Gebrehiwet Bahta

Abstract:

Asmara, the capital city of Eritrea, is facing a sanitation challenge because the city discharges its wastewater to the environment without any kind of treatment. The aim of this research is to conduct a pre-feasibility study of using constructed wetlands in the peri-urban areas of Asmara for wastewater treatment and reuse. It was found that around 15,000 m³ of wastewater is used daily for agricultural activities, and products are sold in the city's markets, which are claimed to cause some health effects. In this study, three potential sites were investigated around Mai-Bela and an optimum location was selected on the basis of land availability, topography, and geotechnical information. Some types of local microphytes that can be used in constructed wetlands have been identified and documented for further studies. It was found that subsurface constructed wetlands can provide a sufficient pollutant removal with careful planning and design. Following the feasibility study, a preliminary design of screening, grit chamber and subsurface constructed wetland was prepared and cost estimation was done. In the cost estimation part, the filter media was found to be the most expensive part and consists of around 30% percent of the overall cost. The city wastewater drainage runs in two directions and the selected site is located in the southern sub-system, which only carries sewage (separate system). The wastewater analysis conducted particularly around this area (Sembel) indicates high heavy metal levels and organic concentrations, which reveals that there is a high level of industrial pollution in addition to the domestic sewage.

Keywords: agriculture, constructed wetland, Mai-Bela, wastewater reuse

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15074 Design and Analysis of a Lightweight Fire-Resistant Door

Authors: Zainab Fadil, Mouath Alawadhi, Abdullah Alhusainan, Fahad Alqadiri, Abdulaziz Alqadiri

Abstract:

This study investigates how lightweight a fire resistance door will perform with under types of insulation materials. Data is initially collected from various websites, scientific books and research papers. Results show that different layers of insulation in a single door can perform better than one insulator. Furthermore, insulation materials that are lightweight, high strength and low thermal conductivity are the most preferred for fire-rated doors. Whereas heavy weight, low strength, and high thermal conductivity are least preferred for fire-resistance doors. Fire-rated doors specifications, theoretical test methodology, structural analysis, and comparison between five different models with diverse layers insulations are presented. Five different door models are being investigated with different insulation materials and arrangements. Model 1 contains an air gap between door layers. Model 2 includes phenolic foam, mild steel and polyurethane. Model 3 includes phenolic foam and glass wool. Model 4 includes polyurethane and glass wool. Model 5 includes only rock wool between the door layers. It is noticed that model 5 is the most efficient model and its design is simple compared to other models. For this model, numerical calculations are performed to check its efficiency and the results are compared to data from experiments for validation. Good agreement was noticed.

Keywords: fire resistance, insulation, strength, thermal conductivity, lightweight, layers

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15073 A Case Report on Anesthetic Considerations in a Neonate with Isolated Oesophageal Atresia with Radiological Fallacy

Authors: T. Rakhi, Thrivikram Shenoy

Abstract:

Esophageal atresia is a disorder of maldevelopment of esophagus with or without a connection to the trachea. Radiological reviews are needed in consultation with the pediatric surgeon and neonatologist and we report a rare case of esophageal atresia associated with atrial septal defect-patent ductus arteriosus complex. A 2-day old female baby born at term, weighing 3.010kg, admitted to the Neonatal Intensive Care Unit with respiratory distress and excessive oral secretions. On examination, continuous murmur and cyanosis were seen. Esophageal atresia was suspected, after a failed attempt to pass a nasogastric tube. Chest radiograph showed coiling of the nasogastric tube and absent gas shadow in the abdomen. Echocardiography confirmed Patent Ductus Arteriosus with Atrial Septal Defect not in failure and was diagnosed with esophageal atresia with suspected fistula posted for surgical repair. After preliminary management with oxygenation, suctioning in prone position and antibiotics, investigations revealed Hb 17gms serum biochemistry, coagulation profile and C-Reactive Protein Test normal. The baby was premedicated with 5mcg of fentanyl and 100 mcg of midazolam and a rapid awake laryngoscopy was done to rule out difficult airway followed by induction with o2 air, sevo and atracurium 2 mg. Placement of a 3.5 tube was uneventful at first attempt and after confirming bilateral air entry positioned in the lateral position for Right thoracotomy. A pulse oximeter, Echocardiogram, Non-invasive Blood Pressure, temperature and a precordial stethoscope in left axilla were essential monitors. During thoracotomy, both the ends of the esophagus and the fistula could not be located after thorough search suggesting an on table finding of type A esophageal atresia. The baby was repositioned for gastrostomy, and cervical esophagostomy ventilated overnight and extubated uneventful. Absent gas shadow was overlooked and the purpose of this presentation is to create an awareness between the neonatologist, pediatric surgeons and anesthesiologist regarding variation of typing of Tracheoesophageal fistula pre and intraoperatively. A need for imaging modalities warranted for a definitive diagnosis in the presence of a gasless stomach.

Keywords: anesthetic, atrial septal defects, esophageal atresia, patent ductus arteriosus, perioperative, chest x-ray

Procedia PDF Downloads 165
15072 Development of new Ecological Cleaning Process of Metal Sheets

Authors: L. M. López López, J. V. Montesdeoca Contreras, A. R. Cuji Fajardo, L. E. Garzón Muñoz, J. I. Fajardo Seminario

Abstract:

In this article a new method of cleaning process of metal sheets for household appliances was developed, using low-pressure cold plasma. In this context, this research consist in analyze the results of metal sheets cleaning process using plasma and compare with pickling process to determinate the efficiency of each process and the level of contamination produced. Surface Cleaning was evaluated by measuring the contact angle with deionized water, diiodo methane and ethylene glycol, for the calculus of the surface free energy by means of the Fowkes theories and Wu. Showing that low-pressure cold plasma is very efficient both in cleaning process how in environment impact.

Keywords: efficient use of plasma, ecological impact of plasma, metal sheets cleaning means, plasma cleaning process.

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15071 Steam Reforming of Acetic Acid over Microwave-Synthesized Ce0.75Zr0.25O2 Supported Ni Catalysts

Authors: Panumard Kaewmora, Thirasak Rirksomboon, Vissanu Meeyoo

Abstract:

Due to the globally growing demands of petroleum fuel and fossil fuels, the scarcity or even depletion of fossil fuel sources could be inevitable. Alternatively, the utilization of renewable sources, such as biomass, has become attractive to the community. Biomass can be converted into bio-oil by fast pyrolysis. In water phase of bio-oil, acetic acid which is one of its main components can be converted to hydrogen with high selectivity over effective catalysts in steam reforming process. Steam reforming of acetic acid as model compound has been intensively investigated for hydrogen production using various metal oxide supported nickel catalysts and yet they seem to be rapidly deactivated depending on the support utilized. A catalyst support such as Ce1-xZrxO2 mixed oxide was proposed for alleviating this problem with the anticipation of enhancing hydrogen yield. However, catalyst preparation methods play a significant role in catalytic activity and performance of the catalysts. In this work, Ce0.75Zr0.25O2 mixed oxide solid solution support was prepared by urea hydrolysis using microwave as heat source. After that nickel metal was incorporated at 15 wt% by incipient wetness impregnation method. The catalysts were characterized by several techniques including BET, XRD, H2-TPR, XRF, SEM, and TEM as well as tested for the steam reforming of acetic acid at various operating conditions. Preliminary results showed that a hydrogen yield of ca. 32% with a relatively high acetic conversion was attained at 650°C.

Keywords: acetic acid, steam reforming, microwave, nickel, ceria, zirconia

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15070 A Five-Year Experience of Intensity Modulated Radiotherapy in Nasopharyngeal Carcinomas in Tunisia

Authors: Omar Nouri, Wafa Mnejja, Fatma Dhouib, Syrine Zouari, Wicem Siala, Ilhem Charfeddine, Afef Khanfir, Leila Farhat, Nejla Fourati, Jamel Daoud

Abstract:

Purpose and Objective: Intensity modulated radiation (IMRT) technique, associated with induction chemotherapy (IC) and/or concomitant chemotherapy (CC), is actually the recommended treatment modality for nasopharyngeal carcinomas (NPC). The aim of this study was to evaluate the therapeutic results and the patterns of relapse with this treatment protocol. Material and methods: A retrospective monocentric study of 145 patients with NPC treated between June 2016 and July 2021. All patients received IMRT with integrated simultaneous boost (SIB) of 33 daily fractions at a dose of 69.96 Gy for high-risk volume, 60 Gy for intermediate risk volume and 54 Gy for low-risk volume. The high-risk volume dose was 66.5 Gy in children. Survival analysis was performed according to the Kaplan-Meier method, and the Log-rank test was used to compare factors that may influence survival. Results: Median age was 48 years (11-80) with a sex ratio of 2.9. One hundred-twenty tumors (82.7%) were classified as stages III-IV according to the 2017 UICC TNM classification. Ten patients (6.9%) were metastatic at diagnosis. One hundred-thirty-five patient (93.1%) received IC, 104 of which (77%) were TPF-based (taxanes, cisplatin and 5 fluoro-uracil). One hundred-thirty-eight patient (95.2%) received CC, mostly cisplatin in 134 cases (97%). After a median follow-up of 50 months [22-82], 46 patients (31.7%) had a relapse: 12 (8.2%) experienced local and/or regional relapse after a median of 18 months [6-43], 29 (20%) experienced distant relapse after a median of 9 months [2-24] and 5 patients (3.4%) had both. Thirty-five patients (24.1%) died, including 5 (3.4%) from a cause other than their cancer. Three-year overall survival (OS), cancer specific survival, disease free survival, metastasis free survival and loco-regional free survival were respectively 78.1%, 81.3%, 67.8%, 74.5% and 88.1%. Anatomo-clinic factors predicting OS were age > 50 years (88.7 vs. 70.5%; p=0.004), diabetes history (81.2 vs. 66.7%; p=0.027), UICC N classification (100 vs. 95 vs. 77.5 vs. 68.8% respectively for N0, N1, N2 and N3; p=0.008), the practice of a lymph node biopsy (84.2 vs. 57%; p=0.05), and UICC TNM stages III-IV (93.8 vs. 73.6% respectively for stage I-II vs. III-IV; p=0.044). Therapeutic factors predicting OS were a number of CC courses (less than 4 courses: 65.8 vs. 86%; p=0.03, less than 5 courses: 71.5 vs. 89%; p=0.041), a weight loss > 10% during treatment (84.1 vs. 60.9%; p=0.021) and a total cumulative cisplatin dose, including IC and CC, < 380 mg/m² (64.4 vs. 87.6%; p=0.003). Radiotherapy delay and total duration did not significantly affect OS. No grade 3-4 late side effects were noted in the evaluable 127 patients (87.6%). The most common toxicity was dry mouth which was grade 2 in 47 cases (37%) and grade 1 in 55 cases (43.3%).Conclusion: IMRT for nasopharyngeal carcinoma granted a high loco-regional control rate for patients during the last five years. However, distant relapses remain frequent and conditionate the prognosis. We identified many anatomo-clinic and therapeutic prognosis factors. Therefore, high-risk patients require a more aggressive therapeutic approach, such as radiotherapy dose escalation or adding adjuvant chemotherapy.

Keywords: therapeutic results, prognostic factors, intensity-modulated radiotherapy, nasopharyngeal carcinoma

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15069 Piled Critical Size Bone-Biomimetic and Biominerizable Nanocomposites: Formation of Bioreactor-Induced Stem Cell Gradients under Perfusion and Compression

Authors: W. Baumgartner, M. Welti, N. Hild, S. C. Hess, W. J. Stark, G. Meier Bürgisser, P. Giovanoli, J. Buschmann

Abstract:

Perfusion bioreactors are used to solve problems in tissue engineering in terms of sufficient nutrient and oxygen supply. Such problems especially occur in critical size grafts because vascularization is often too slow after implantation ending up in necrotic cores. Biominerizable and biocompatible nanocomposite materials are attractive and suitable scaffold materials for bone tissue engineering because they offer mineral components in organic carriers – mimicking natural bone tissue. In addition, human adipose derived stem cells (ASCs) can potentially be used to increase bone healing as they are capable of differentiating towards osteoblasts or endothelial cells among others. In the present study, electrospun nanocomposite disks of poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/a-CaP) were seeded with human ASCs and eight disks were stacked in a bioreactor running with normal culture medium (no differentiation supplements). Under continuous perfusion and uniaxial cyclic compression, load-displacement curves as a function of time were assessed. Stiffness and energy dissipation were recorded. Moreover, stem cell densities in the layers of the piled scaffold were determined as well as their morphologies and differentiation status (endothelial cell differentiation, chondrogenesis and osteogenesis). While the stiffness of the cell free constructs increased over time caused by the transformation of the a-CaP nanoparticles into flake-like apatite, ASC-seeded constructs showed a constant stiffness. Stem cell density gradients were histologically determined with a linear increase in the flow direction from the bottom to the top of the 3.5 mm high pile (r2 > 0.95). Cell morphology was influenced by the flow rate, with stem cells getting more roundish at higher flow rates. Less than 1 % osteogenesis was found upon osteopontin immunostaining at the end of the experiment (9 days), while no endothelial cell differentiation and no chondrogenesis was triggered under these conditions. All ASCs had mainly remained in their original pluripotent status within this time frame. In summary, we have fabricated a critical size bone graft based on a biominerizable bone-biomimetic nanocomposite with preserved stiffness when seeded with human ASCs. The special feature of this bone graft was that ASC densities inside the piled construct varied with a linear gradient, which is a good starting point for tissue engineering interfaces such as bone-cartilage where the bone tissue is cell rich while the cartilage exhibits low cell densities. As such, this tissue-engineered graft may act as a bone-cartilage interface after the corresponding differentiation of the ASCs.

Keywords: bioreactor, bone, cartilage, nanocomposite, stem cell gradient

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15068 A Reusable Foundation Solution for Onshore Windmills

Authors: Wael Mohamed, Per-Erik Austrell, Ola Dahlblom

Abstract:

Wind farms repowering is a significant topic nowadays. Wind farms repowering means the complete dismantling of the existing turbine, tower and foundation at an existing site and replacing these units with taller and larger units. Modern wind turbines are designed to withstand approximately for 20~25 years. However, a very long design life of 100 years or more can be expected for high-quality concrete foundations. Based on that there are significant economic and environmental benefits of replacing the out-of-date wind turbine with a new turbine of better power generation capacity and reuse the foundation. The big difference in lifetime shows a potential for new foundation solution to allow wind farms to be updated with taller and larger units in order to increase the energy production. This also means a significant change in the design loads on the foundations. Therefore, the new foundation solution should be able to handle the additional overturning loads. A raft surrounded by an active stabilisation system is proposed in this study. The concept of an active stabilisation system is a novel idea using a movable load to stabilise against the overturning moment. The active stabilisation system consists of a water tank being divided into eight compartments. The system uses the water as a movable load by pumping it into two compartments to stabilise against the overturning moment. The position of the water will rely on the wind direction and a water movement system depending on a number of electric motors and pipes with electric valves is used. One of the advantages of this active foundation solution is that some cost-efficient adjustment could be done to make this foundation able to support larger and taller units. After the end of the first turbine lifetime, an option is presented here to reuse this foundation and make it able to support taller and larger units. This option is considered using extra water volume to fill four compartments instead of two compartments. This extra water volume will increase the stability moment by 41% compared to using water in two compartments. The geotechnical performance of the new foundation solution is investigated using two existing weak soil profiles in Egypt and Sweden. A comparative study of the new solution and a piled raft with long friction piles is performed using finite element simulations. The results show that using a raft surrounded by an active stabilisation system decreases the tilting compared to a piled raft with friction piles. Moreover, it is found that using a raft surrounded by an active stabilisation system decreases the foundation costs compared to a piled raft with friction piles. In term of the environmental impact, it is found that the new foundation has a beneficial impact on the CO2 emissions. It saves roughly from 296.1 tonnes-CO2 to 518.21 tonnes-CO2 from the manufacture of concrete if the new foundation solution is used for another turbine-lifetime.

Keywords: active stabilisation system, CO2 emissions, FE analysis, reusable, weak soils

Procedia PDF Downloads 202
15067 Contemporary Christian Mission in Nigeria, the Question of Identity and Self-Realization for Integral Development

Authors: Felix Ehimare Enegho

Abstract:

The issue of the Christian mission among various people in our world has become a subject of discussion for quite a while now considering the many challenges faced by people of different religions. The understanding of who we are and how we choose to live our life as a people is quite imperative in many societies. The Christian Church down through the ages attempted to define itself so as to become relevant in human society. In Africa, the question of identity and self-realization is quite imperative if Africans are to define themselves and place themselves in the proper perspective as Christians. With the high level of insecurity bedevilling the world and especially Nigerian society, there is the need for Christians in Nigeria to see themselves as one body belonging to the same family. It is however disheartening that for several years now, there is a high level of disunity, lack of trust, disharmony, and vices of all kinds even among Christians who are often too quick to segment themselves into denominations thereby making themselves weak, segmented ad powerless in the midst of great oppositions, as if the Christian church in Nigeria is a divided house. The significance of this paper is to explore the areas of conflict among Christians in Nigeria with a view to finding possible solutions that would lead to the integral formation and in the long run a common identity and invariably self-realization. This paper utilized the socio-historical method of research. Among the major findings in the work is the fact that it is only people that can truly be responsible and held accountable for how they define their identity and self-realization. This entails that Christianity’s identity and self-realization in Nigeria will not only lead to a better and more defined form of Christianity but would ultimately assist in the integral development of Christian mission in Nigeria, a kind of development that would lead to a better Nigerian society.

Keywords: contemporary, Christian, mission, Nigeria, identity, self-realization

Procedia PDF Downloads 68
15066 Light-Weight Network for Real-Time Pose Estimation

Authors: Jianghao Hu, Hongyu Wang

Abstract:

The effective and efficient human pose estimation algorithm is an important task for real-time human pose estimation on mobile devices. This paper proposes a light-weight human key points detection algorithm, Light-Weight Network for Real-Time Pose Estimation (LWPE). LWPE uses light-weight backbone network and depthwise separable convolutions to reduce parameters and lower latency. LWPE uses the feature pyramid network (FPN) to fuse the high-resolution, semantically weak features with the low-resolution, semantically strong features. In the meantime, with multi-scale prediction, the predicted result by the low-resolution feature map is stacked to the adjacent higher-resolution feature map to intermediately monitor the network and continuously refine the results. At the last step, the key point coordinates predicted in the highest-resolution are used as the final output of the network. For the key-points that are difficult to predict, LWPE adopts the online hard key points mining strategy to focus on the key points that hard predicting. The proposed algorithm achieves excellent performance in the single-person dataset selected in the AI (artificial intelligence) challenge dataset. The algorithm maintains high-precision performance even though the model only contains 3.9M parameters, and it can run at 225 frames per second (FPS) on the generic graphics processing unit (GPU).

Keywords: depthwise separable convolutions, feature pyramid network, human pose estimation, light-weight backbone

Procedia PDF Downloads 140
15065 Modification of Carbon-Based Gas Sensors for Boosting Selectivity

Authors: D. Zhao, Y. Wang, G. Chen

Abstract:

Gas sensors that utilize carbonaceous materials as sensing media offer numerous advantages, making them the preferred choice for constructing chemical sensors over those using other sensing materials. Carbonaceous materials, particularly nano-sized ones like carbon nanotubes (CNTs), provide these sensors with high sensitivity. Additionally, carbon-based sensors possess other advantageous properties that enhance their performance, including high stability, low power consumption for operation, and cost-effectiveness in their construction. These properties make carbon-based sensors ideal for a wide range of applications, especially in miniaturized devices created through MEMS or NEMS technologies. To capitalize on these properties, a group of chemoresistance-type carbon-based gas sensors was developed and tested against various volatile organic compounds (VOCs) and volatile inorganic compounds (VICs). The results demonstrated exceptional sensitivity to both VOCs and VICs, along with the sensor’s long-term stability. However, this broad sensitivity also led to poor selectivity towards specific gases. This project aims at addressing the selectivity issue by modifying the carbon-based sensing materials and enhancing the sensor's specificity to individual gas. Multiple groups of sensors were manufactured and modified using proprietary techniques. To assess their performance, we conducted experiments on representative sensors from each group to detect a range of VOCs and VICs. The VOCs tested included acetone, dimethyl ether, ethanol, formaldehyde, methane, and propane. The VICs comprised carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2), nitric oxide (NO), and nitrogen dioxide (NO2). The concentrations of the sample gases were all set at 50 parts per million (ppm). Nitrogen (N2) was used as the carrier gas throughout the experiments. The results of the gas sensing experiments are as follows. In Group 1, the sensors exhibited selectivity toward CO2, acetone, NO, and NO2, with NO2 showing the highest response. Group 2 primarily responded to NO2. Group 3 displayed responses to nitrogen oxides, i.e., both NO and NO2, with NO2 slightly surpassing NO in sensitivity. Group 4 demonstrated the highest sensitivity among all the groups toward NO and NO2, with NO2 being more sensitive than NO. In conclusion, by incorporating several modifications using carbon nanotubes (CNTs), sensors can be designed to respond well to NOx gases with great selectivity and without interference from other gases. Because the response levels to NO and NO2 from each group are different, the individual concentration of NO and NO2 can be deduced.

Keywords: gas sensors, carbon, CNT, MEMS/NEMS, VOC, VIC, high selectivity, modification of sensing materials

Procedia PDF Downloads 106
15064 Realistic Simulation Methodology in Brazil’s New Medical Education Curriculum: Potentialities

Authors: Cleto J. Sauer Jr

Abstract:

Introduction: Brazil’s new national curriculum guidelines (NCG) for medical education were published in 2014, presenting active learning methodologies as a cornerstone. Simulation was initially applied for aviation pilots’ training and is currently applied in health sciences. The high-fidelity simulator replicates human body anatomy in detail, also reproducing physiological functions and its use is increasing in medical schools. Realistic Simulation (RS) has pedagogical aspects that are aligned with Brazil’s NCG teaching concepts. The main objective of this study is to carry on a narrative review on RS’s aspects that are aligned with Brazil’s new NCG teaching concepts. Methodology: A narrative review was conducted, with search in three databases (PubMed, Embase and BVS) of studies published between 2010 and 2020. Results: After systematized search, 49 studies were selected and divided into four thematic groups. RS is aligned with new Brazilian medical curriculum as it is an active learning methodology, providing greater patient safety, uniform teaching, and student's emotional skills enhancement. RS is based on reflective learning, a teaching concept developed for adult’s education. Conclusion: RS is a methodology aligned with NCG teaching concepts and has potential to assist in the implementation of new Brazilian medical school’s curriculum. It is an immersive and interactive methodology, which provides reflective learning in a safe environment for students and patients.

Keywords: curriculum, high-fidelity simulator, medical education, realistic simulation

Procedia PDF Downloads 143
15063 Nonlinear Analysis of Torsionally Loaded Steel Fibred Self-Compacted Concrete Beams Reinforced by GFRP Bars

Authors: Khaled Saad Eldin Mohamed Ragab

Abstract:

This paper investigates analytically the torsion behavior of steel fibered high strength self compacting concrete beams reinforced by GFRP bars. Nonlinear finite element analysis on 12­ beams specimens was achieved by using ANSYS software. The nonlinear finite element analysis program ANSYS is utilized owing to its capabilities to predict either the response of reinforced concrete beams in the post elastic range or the ultimate strength of a reinforced concrete beams produced from steel fiber reinforced self compacting concrete (SFRSCC) and reinforced by GFRP bars. A general description of the finite element method, theoretical modeling of concrete and reinforcement are presented. In order to verify the analytical model used in this research using test results of the experimental data, the finite element analysis were performed. Then, a parametric study of the effect ratio of volume fraction of steel fibers in ordinary strength concrete, the effect ratio of volume fraction of steel fibers in high strength concrete, and the type of reinforcement of stirrups were investigated. A comparison between the experimental results and those predicted by the existing models are presented. Results and conclusions thyat may be useful for designers have been raised and represented.

Keywords: nonlinear analysis, torsionally loaded, self compacting concrete, steel fiber reinforced self compacting concrete (SFRSCC), GFRP bars and sheets

Procedia PDF Downloads 445
15062 Extraction of Scandium (Sc) from an Ore with Functionalized Nanoporous Silicon Adsorbent

Authors: Arezoo Rahmani, Rinez Thapa, Juha-Matti Aalto, Petri Turhanen, Jouko Vepsalainen, Vesa-PekkaLehto, Joakim Riikonen

Abstract:

Production of Scandium (Sc) is a complicated process because Sc is found only in low concentrations in ores and the concentration of Sc is very low compared with other metals. Therefore, utilization of typical extraction processes such as solvent extraction is problematic in scandium extraction. The Adsorption/desorption method can be used, but it is challenging to prepare materials, which have good selectivity, high adsorption capacity, and high stability. Therefore, efficient and environmentally friendly methods for Sc extraction are needed. In this study, the nanoporous composite material was developed for extracting Sc from an Sc ore. The nanoporous composite material offers several advantageous properties such as large surface area, high chemical and mechanical stability, fast diffusion of the metals in the material and possibility to construct a filter out of the material with good flow-through properties. The nanoporous silicon material was produced by first stabilizing the surfaces with a silicon carbide layer and then functionalizing the surface with bisphosphonates that act as metal chelators. The surface area and porosity of the material were characterized by N₂ adsorption and the morphology was studied by scanning electron microscopy (SEM). The bisphosphonate content of the material was studied by thermogravimetric analysis (TGA). The concentration of metal ions in the adsorption/desorption experiments was measured with inductively coupled plasma mass spectrometry (ICP-MS). The maximum capacity of the material was 25 µmol/g Sc at pH=1 and 45 µmol/g Sc at pH=3, obtained from adsorption isotherm. The selectivity of the material towards Sc in artificial solutions containing several metal ions was studied at pH one and pH 3. The result shows good selectivity of the nanoporous composite towards adsorption of Sc. Scandium was less efficiently adsorbed from solution leached from the ore of Sc because of excessive amounts of iron (Fe), aluminum (Al) and titanium (Ti) which disturbed the adsorption process. For example, the concentration of Fe was more than 4500 ppm, while the concentration of Sc was only three ppm, approximately 1500 times lower. Precipitation methods were developed to lower the concentration of the metals other than Sc. Optimal pH for precipitation was found to be pH 4. The concentration of Fe, Al and Ti were decreased by 99, 70, 99.6%, respectively, while the concentration of Sc decreased only 22%. Despite the large reduction in the concentration of other metals, more work is needed to further increase the relative concentration of Sc compared with other metals to efficiently extract it using the developed nanoporous composite material. Nevertheless, the developed material may provide an affordable, efficient and environmentally friendly method to extract Sc on a large scale.

Keywords: adsorption, nanoporous silicon, ore solution, scandium

Procedia PDF Downloads 132
15061 Investigation of Bending Behavior of Ultra High Performance Concrete with Steel and Glass Fiber Polymer Reinforcement

Authors: Can Otuzbir

Abstract:

It is one of the most difficult areas of civil engineering to provide long-lasting structures with the rapid development of concrete and reinforced concrete structures. Concrete is a living material, and the structure where the concrete is located is constantly exposed to external influences. One of these effects is reinforcement corrosion. Reinforcement corrosion of reinforced concrete structures leads to a significant decrease in the carrying capacity of the structural elements, as well as reduced service life. It is undesirable that the service life should be completed sooner than expected. In recent years, advances in glass fiber technology and its use with concrete have developed rapidly. As a result of inability to protect steel reinforcements against corrosion, fiberglass reinforcements have started to be investigated as an alternative material to steel reinforcements, and researches and experimental studies are still continuing. Glass fiber reinforcements have become an alternative material to steel reinforcement because they are resistant to corrosion, lightweight and simple to install compared to steel reinforcement. Glass fiber reinforcements are not corroded and have higher tensile strength, longer life, lighter and insulating properties compared to steel reinforcement. In experimental studies, glass fiber reinforcements have been shown to show superior mechanical properties similar to beams produced with steel reinforcement. The performance of long-term use of glass fiber fibers continues with accelerated experimental studies.

Keywords: glass fiber polymer reinforcement, steel fiber concrete, ultra high performance concrete, bending, GFRP

Procedia PDF Downloads 112
15060 Magnetofluidics for Mass Transfer and Mixing Enhancement in a Micro Scale Device

Authors: Majid Hejazian, Nam-Trung Nguyen

Abstract:

Over the past few years, microfluidic devices have generated significant attention from industry and academia due to advantages such as small sample volume, low cost and high efficiency. Microfluidic devices have applications in chemical, biological and industry analysis and can facilitate assay of bio-materials and chemical reactions, separation, and sensing. Micromixers are one of the important microfluidic concepts. Micromixers can work as stand-alone devices or be integrated in a more complex microfluidic system such as a lab on a chip (LOC). Micromixers are categorized as passive and active types. Passive micromixers rely only on the arrangement of the phases to be mixed and contain no moving parts and require no energy. Active micromixers require external fields such as pressure, temperature, electric and acoustic fields. Rapid and efficient mixing is important for many applications such as biological, chemical and biochemical analysis. Achieving fast and homogenous mixing of multiple samples in the microfluidic devices has been studied and discussed in the literature recently. Improvement in mixing rely on effective mass transport in microscale, but are currently limited to molecular diffusion due to the predominant laminar flow in this size scale. Using magnetic field to elevate mass transport is an effective solution for mixing enhancement in microfluidics. The use of a non-uniform magnetic field to improve mass transfer performance in a microfluidic device is demonstrated in this work. The phenomenon of mixing ferrofluid and DI-water streams has been reported before, but mass transfer enhancement for other non-magnetic species through magnetic field have not been studied and evaluated extensively. In the present work, permanent magnets were used in a simple microfluidic device to create a non-uniform magnetic field. Two streams are introduced into the microchannel: one contains fluorescent dye mixed with diluted ferrofluid to induce enhanced mass transport of the dye, and the other one is a non-magnetic DI-water stream. Mass transport enhancement of fluorescent dye is evaluated using fluorescent measurement techniques. The concentration field is measured for different flow rates. Due to effect of magnetic field, a body force is exerted on the paramagnetic stream and expands the ferrofluid stream into non-magnetic DI-water flow. The experimental results demonstrate that without a magnetic field, both magnetic nanoparticles of the ferrofluid and the fluorescent dye solely rely on molecular diffusion to spread. The non-uniform magnetic field, created by the permanent magnets around the microchannel, and diluted ferrofluid can improve mass transport of non-magnetic solutes in a microfluidic device. The susceptibility mismatch between the fluids results in a magnetoconvective secondary flow towards the magnets and subsequently the mass transport of the non-magnetic fluorescent dye. A significant enhancement in mass transport of the fluorescent dye was observed. The platform presented here could be used as a microfluidics-based micromixer for chemical and biological applications.

Keywords: ferrofluid, mass transfer, micromixer, microfluidics, magnetic

Procedia PDF Downloads 211
15059 Measurements for Risk Analysis and Detecting Hazards by Active Wearables

Authors: Werner Grommes

Abstract:

Intelligent wearables (illuminated vests or hand and foot-bands, smart watches with a laser diode, Bluetooth smart glasses) overflow the market today. They are integrated with complex electronics and are worn very close to the body. Optical measurements and limitation of the maximum light density are needed. Smart watches are equipped with a laser diode or control different body currents. Special glasses generate readable text information that is received via radio transmission. Small high-performance batteries (lithium-ion/polymer) supply the electronics. All these products have been tested and evaluated for risk. These products must, for example, meet the requirements for electromagnetic compatibility as well as the requirements for electromagnetic fields affecting humans or implant wearers. Extensive analyses and measurements were carried out for this purpose. Many users are not aware of these risks. The result of this study should serve as a suggestion to do it better in the future or simply to point out these risks. Commercial LED warning vests, LED hand and foot-bands, illuminated surfaces with inverter (high voltage), flashlights, smart watches, and Bluetooth smart glasses were checked for risks. The luminance, the electromagnetic emissions in the low-frequency as well as in the high-frequency range, audible noises, and nervous flashing frequencies were checked by measurements and analyzed. Rechargeable lithium-ion or lithium-polymer batteries can burn or explode under special conditions like overheating, overcharging, deep discharge or using out of the temperature specification. Some risk analysis becomes necessary. The result of this study is that many smart wearables are worn very close to the body, and an extensive risk analysis becomes necessary. Wearers of active implants like a pacemaker or implantable cardiac defibrillator must be considered. If the wearable electronics include switching regulators or inverter circuits, active medical implants in the near field can be disturbed. A risk analysis is necessary.

Keywords: safety and hazards, electrical safety, EMC, EMF, active medical implants, optical radiation, illuminated warning vest, electric luminescent, hand and head lamps, LED, e-light, safety batteries, light density, optical glare effects

Procedia PDF Downloads 98
15058 Dielectric Properties of Thalium Selenide Thin Films at Radio Wave Frequencies

Authors: Onur Potok, Deniz Deger, Kemal Ulutas, Sahin Yakut, Deniz Bozoglu

Abstract:

Thalium Selenide (TlSe) is used for optoelectronic devices, pressure sensitive detectors, and gamma-ray detectors. The TlSe samples were grown as large single crystals using the Stockbarger-Bridgman method. The thin films, in the form of Al/TlSe/Al, were deposited on the microscope slide in different thicknesses (300-3000 Å) using thermal evaporation technique at 10-5 Torr. The dielectric properties of (TlSe) thin films, capacitance (C) and dielectric loss factor (tanδ), were measured in a frequency range of 10-105 Hz, and temperatures between 213K and 393K via Broadband Dielectric Spectroscopy analyzer. The dielectric constant (ε’) and the dielectric loss (ε’’) of the thin films were derived from measured parameters (C and tanδ). These results showed that the dielectric properties of TlSe thin films are frequency and temperature dependent. The capacitance and the dielectric constant decrease with increasing frequency and decreasing temperature. The dielectric loss of TlSe thin films decreases with increasing frequency, on the other hand, they increase with increasing temperature and increasing thicknesses. There is two relaxation region in the investigated frequency and temperature interval. These regions can be called as low and high-frequency dispersion regions. Low-frequency dispersion region can be attributed to the polarization of the main part of the chain structure of TlSe while high-frequency dispersion region can be attributed to the polarization of side parts of the structure.

Keywords: thin films, thallium selenide, dielectric spectroscopy, binary compounds

Procedia PDF Downloads 138
15057 How Do L1 Teachers Assess Haitian Immigrant High School Students in Chile?

Authors: Gloria Toledo, Andrea Lizasoain, Leonardo Mena

Abstract:

Immigration has largely increased in Chile in the last 20 years. About 6.6% of our population is foreign, from which 14.3% is Haitian. Haitians are between 15 and 29 years old and have come to Chile escaping from a social crisis. They believe that education and work will help them do better in life. Therefore, rates of Haitian students in the Chilean school system have also increased: there were 3,121 Haitian students enrolled in 2017. This is a challenge for the public school, which takes in young people who must face schooling, social immersion and learning of a second language simultaneously. The linguistic barrier affects both students’ and teachers’ adaptation process, which has an impact on the students’ academic performance and consequent acquisition of Spanish. In order to explore students’ academic performance and interlanguage development, we examined how L1 teachers assess Haitian high school students’ written production in Spanish. With this purpose, teachers were asked to use a specially designed grid to assess correction, accommodation, lexical and analytical complexity, organization and fluency of both Haitian and Chilean students. Parallelly, texts were approached from an error analysis perspective. Results from grids and error analysis were then compared. On the one hand, it has been found that teachers give very little feedback to students apart from scores and grades, which does not contribute to the development of the second language. On the other hand, error analysis has yielded that Haitian students are in a dynamic process of the acquisition of Spanish, which could be enhanced if L1 teacher were aware of the process of interlanguage developmen.

Keywords: assessment, error analysis, grid, immigration, Spanish aquisition, writing

Procedia PDF Downloads 119
15056 Effect of Dietary Organic Zinc Supplementation on Immunocompetance and Reproductive Performance in Rats

Authors: D. Nagalakshmi, S. Parashuramulu K. Sadasiva Rao, G. Aruna, L. Vikram

Abstract:

The zinc (Zn) is the second most abundant trace element in mammals and birds, forming structural component of over 300 enzymes, playing an important role in anti-oxidant defense, immune response and reproduction. Organic trace minerals are more readily absorbed from the digestive tract and more biologically available compared with its inorganic salt. Thus, the present study was undertaken on 60 adult female Sprague Dawley rats (275±2.04 g) for experimental duration of 12 weeks to investigate the effect of dietary Zn supplementation from various organic sources on immunity, reproduction, oxidative defense mechanism and blood biochemical profile. The rats were randomly allotted to 30 replicates (2 per replicate) which were in turn randomly allotted to 5 dietary treatments varying in Zn source i.e., one inorganic source (Zn carbonate) and 4 organic sources (Zn-proteinate, Zn-propionate, Zn-amino acid complex and Zn-methionine) so as to supply NRC recommended Zn concentration (12 ppm Zn). Supplementation of organic Zn had no effect on various haematological and serum biochemical constituents compared to inorganic Zn fed rats. The TBARS and protein carbonyls concentration in liver indicative of oxidative stress was comparable between various organic and inorganic groups. The glutathione reductase activity in haemolysate (P<0.05) and reduced glutathione concentration in liver (P<0.01) was higher when fed organic Zn and RBC catalase activity was higher (P<0.01) on Zn methionine compared to other organic sources tested and the inorganic source. The humoral immune response assessed as antibody titres against sheep RBC was higher (P<0.05) when fed organic sources of zinc compared to inorganic source. The cell mediated immune response expressed as delayed type hypersensitivity reaction was higher (P<0.05) in rats fed Zn propionate with no effect of other organic Zn sources. The serum progesterone concentration was higher (P<0.05) in rats fed organic Zn sources compared to inorganic zinc. The data on ovarian folliculogenesis indicated that organic Zn supplementation increased (P<0.05) the number of graafian follicles and corpus luteum with no effect on primary, secondary and tertiary follicle number. The study indicated that rats fed organic sources of Zn had higher antioxidant enzyme activities, immune response and serum progesterone concentration with higher number of mature follicles. Though the effect of feeding various organic sources were comparable, rats fed zinc methionine had higher antioxidant activity and cell mediated immune response was higher in rats on Zn propionate.

Keywords: organic zinc, immune, rats, reproductive

Procedia PDF Downloads 275
15055 The Batteryless Wi-Fi Backscatter System and Method for Improving the Transmission Range

Authors: Young-Min Ko, Seung-Jun Yu, Seongjoo Lee, Hyoung-Kyu Song

Abstract:

The Internet of things (IoT) system has attracted attention. IoT is a technology to connect all the objects to the internet as well as computer. IoT makes it possible for providing more data interoperability methods for an application purpose. Among the IoT technology, the research of devices so that they can communicate without power supply has been actively conducted. Batteryless system permits us to communicate without power supply devices. In this paper, batteryless backscatter system is used as a tag. And mobile devices which are embedded wireless fidelity (Wi-Fi) chipset are used as a reader. The backscatter tag can be obtained Internet connectivity from the reader. Conventional Wi-Fi backscatter system has limitation in the transmission range. In this paper, the proposed algorithm can be obtained improved reliability as well as overcoming the limitation about transmission range.

Keywords: Ambient RF, Backscatter, Batteryless communication, Energy-harvesting, IoT, RFID, Tag, Wi-Fi

Procedia PDF Downloads 375