Search results for: experimental test

Authors: A. J. Cobley, L. Krishnan

Abstract:

The demand for multi-functional lightweight materials in sectors such as automotive, aerospace, electronics is growing, and for this reason fibre-reinforced, epoxy polymer composites are being widely utilized. The fibre reinforcing material is mainly responsible for the strength and stiffness of the composites whilst the main role of the epoxy polymer matrix is to enhance the load distribution applied on the fibres as well as to protect the fibres from the effect of harmful environmental conditions. The superior properties of the fibre-reinforced composites are achieved by the best properties of both of the constituents. Although factors such as the chemical nature of the epoxy and how it is cured will have a strong influence on the properties of the epoxy matrix, the method of mixing and degassing of the resin can also have a significant impact. The production of a fibre-reinforced epoxy polymer composite will usually begin with the mixing of the epoxy pre-polymer with a hardener and accelerator. Mechanical methods of mixing are often employed for this stage but such processes naturally introduce air into the mixture, which, if it becomes entrapped, will lead to voids in the subsequent cured polymer. Therefore, degassing is normally utilised after mixing and this is often achieved by placing the epoxy resin mixture in a vacuum chamber. Although this is reasonably effective, it is another process stage and if a method of mixing could be found that, at the same time, degassed the resin mixture this would lead to shorter production times, more effective degassing and less voids in the final polymer. In this study the effect of four different methods for mixing and degassing of the pre-polymer with hardener and accelerator were investigated. The first two methods were manual stirring and magnetic stirring which were both followed by vacuum degassing. The other two techniques were ultrasonic mixing/degassing using a 40 kHz ultrasonic bath and a 20 kHz ultrasonic probe. The cured cast resin samples were examined under scanning electron microscope (SEM), optical microscope, and Image J analysis software to study morphological changes, void content and void distribution. Three point bending test and differential scanning calorimetry (DSC) were also performed to determine the thermal and mechanical properties of the cured resin. It was found that the use of the 20 kHz ultrasonic probe for mixing/degassing gave the lowest percentage voids of all the mixing methods in the study. In addition, the percentage voids found when employing a 40 kHz ultrasonic bath to mix/degas the epoxy polymer mixture was only slightly higher than when magnetic stirrer mixing followed by vacuum degassing was utilized. The effect of ultrasonic mixing/degassing on the thermal and mechanical properties of the cured resin will also be reported. The results suggest that low frequency ultrasound is an effective means of mixing/degassing a pre-polymer mixture and could enable a significant reduction in production times.

Keywords: degassing, low frequency ultrasound, polymer composites, voids

Procedia PDF Downloads 291

Authors: Bashar Mahmoud, Lee Mortimer, Michael Fairweather

Abstract:

New methods have recently been introduced to improve the thermal property values of molten nitrate salts (a binary mixture of NaNO3:KNO3in 60:40 wt. %), by doping them with minute concentration of nanoparticles in the range of 0.5 to 1.5 wt. % to form the so-called: Nano-heat-transfer-fluid, apt for thermal energy transfer and storage applications. The present study aims to assess the stability of these nanofluids using the advanced computational modelling technique, Lagrangian particle tracking. A multi-phase solid-liquid model is used, where the motion of embedded nanoparticles in the suspended fluid is treated by an Euler-Lagrange hybrid scheme with fixed time stepping. This technique enables measurements of various multi-scale forces whose characteristic (length and timescales) are quite different. Two systems are considered, both consisting of 50 nm Al2O3 ceramic nanoparticles suspended in fluids of different density ratios. This includes both water (5 to 95 °C) and molten nitrate salt (220 to 500 °C) at various volume fractions ranging between 1% to 5%. Dynamic properties of both phases are coupled to the ambient temperature of the fluid suspension. The three-dimensional computational region consists of a 1μm cube and particles are homogeneously distributed across the domain. Periodic boundary conditions are enforced. The particle equations of motion are integrated using the fourth order Runge-Kutta algorithm with a very small time-step, Δts, set at 10-11 s. The implemented technique demonstrates the key dynamics of aggregated nanoparticles and this involves: Brownian motion, soft-sphere particle-particle collisions, and Derjaguin, Landau, Vervey, and Overbeek (DLVO) forces. These mechanisms are responsible for the predictive model of aggregation of nano-suspensions. An energy transport-based method of predicting the thermal conductivity of the nanofluids is also used to determine thermal properties of the suspension. The simulation results confirms the effectiveness of the technique. The values are in excellent agreement with the theoretical and experimental data obtained from similar studies. The predictions indicates the role of Brownian motion and DLVO force (represented by both the repulsive electric double layer and an attractive Van der Waals) and its influence in the level of nanoparticles agglomeration. As to the nano-aggregates formed that was found to play a key role in governing the thermal behavior of nanofluids at various particle concentration. The presentation will include a quantitative assessment of these forces and mechanisms, which would lead to conclusions about nanofluids, heat transfer performance and thermal characteristics and its potential application in solar thermal energy plants.

Keywords: thermal energy storage, molten salt, nano-fluids, multi-scale computational modelling

Procedia PDF Downloads 181

Authors: Heba Kamal Mohamed

Abstract:

Introduction: Tramadol is a weak -opioid receptor agonist with an analgesic effect because of the inhibition of uptake of norepinephrine and serotonin. Nowadays, tramadol hydrochloride is frequently used as a pain reliever. Tramadol is recommended for the management of acute and chronic pain of moderate to severe intensity associated with a variety of diseases or problems, including osteoarthritis, diabetic neuropathy, neuropathic pain, and even perioperative pain in human patients. In obstetrics and gynecology, tramadol is used extensively to treat postoperative pain. Aim of the study: This study was undertaken to investigate the histological (light and electron microscopic) and immunohistochemical effects of long term tramadol treatment on the ovary of adult rats and the possible recovery after tramadol withdrawal. Design: Experimental study. Materials and methods: Thirty adult female albino rats were used in this study. They were classified into three main groups (10 rats each). Group I served as the control group. Group II, rats were subcutaneously injected with tramadol 40 mg/kg three times per week for 8 weeks. Group III, rats were subcutaneously injected with tramadol 40 mg/kg three times per week for 8 weeks then were kept for another 8 weeks without treatment for recovery. At the end of the experiment rats were sacrificed and bilateral oophorectomy was carried out; the ovaries were processed for histological study (light and electron microscopic) and immunohistochemical reaction for caspase-3 (apoptotic protein). Results: Examination of the ovary of tramadol-treated rats (group II) revealed many atretic ovarian follicles, some follicles showed detachment of the oocyte from surrounding granulosa cells and others showed loss of the oocyte. Many follicles revealed degenerated vacuolated oocytes and vacuolated theca folliculi cells. Granulosa cells appeared shrunken, disrupted and loosely attached with vacuolated cytoplasm and pyknotic nuclei. Some follicles showed separation of granulosa cells from the theca folliculi layer. The ultrastructural study revealed the presence of granulosa cells with electron dense indented nuclei, damaged mitochondria and granular vacuolated cytoplasm. Other cells showed accumulation of large amount of lipid droplets in their cytoplasm. Some follicles revealed rarifaction of the cytoplasm of oocytes and absent zona pellucida. Moreover, apoptotic changes were detected by immunohistochemical staining in the form of increased staining intensity to caspase-3 (apoptotic protein). With Masson's Trichrome stain, there was an increased collagen fibre deposition in the ovarian cortical stroma. The wall of blood vessels appeared thickened. In the withdrawal group (group III), there was a little improvement in the histological and immunohistochemical changes. Conclusion: Tramadol had serious deleterious effects on ovarian structure. Thus, it should be used with caution, especially when a long term treatment is indicated. Withdrawal of tramadol led to a little improvement in the structural impairment of the ovary.

Keywords: tramadol, ovary, withdrawal, rats

Procedia PDF Downloads 284

Authors: Bhavana Gulaty, Arshia Chaudhri

Abstract:

Great civic projects contribute integrally to a city, and every city undergoes a recurring cycle of urban transformations and regeneration by their insertion. The M.I.C.E. (Meetings, Incentives, Convention and Exhibitions) industry is the forbearer of one category of such catalytic civic projects. Through a specific focus on M.I.C.E. destinations, this paper illustrates the multifarious dimensions that urban catalysts impact the city on S.P.U.R. (Seed. Profile. Urbane. Reflections), the theoretical framework of this paper aims to unearth these dimensions in the realm of the COEX (Convention & Exhibition) biosphere. The ‘COEX Biosphere’ is the filter of such catalysts being ecosystems unto themselves. Like a ripple in water, the impact of these strategic interventions focusing on art, culture, trade, and promotion expands right from the trigger; the immediate context to the region and subsequently impacts the global scale. These ripples are known to bring about significant economic, social, and political and network changes. The COEX inventory in the Asian context has one such prominent addition; the proposed India International Convention and Exhibition Centre (IICC) at New Delhi. It is envisioned to be the largest facility in Asia currently and would position India on the global M.I.C.E map. With the first phase of the project scheduled to open for use in the end of 2019, this flagship project of the Government of India is projected to cater to a peak daily footfall of 3,20,000 visitors and estimated to generate 5,00,000 jobs. While the economic benefits are yet to manifest in real time and ‘Good design is good business’ holds true, for the urban transformation to be meaningful, the benefits have to go beyond just a balance sheet for the city’s exchequer. This aspect has been found relatively unexplored in research on these developments. The methodology for investigation will comprise of two steps. The first will be establishing an inventory of the global success stories and associated benefits of COEX projects over the past decade. The rationale for capping the timeframe is the significant paradigm shift that has been observed in their recent conceptualization; for instance ‘Innovation Districts’ conceptualised in the city of Albuquerque that converges into the global economy. The second step would entail a comparative benchmarking of the projected transformations by IICC through a toolkit of parameters. This is posited to yield a matrix that can form the test bed for mapping the catalytic trajectory for projects in the pipeline globally. As a ready reckoner, it purports to be a catalyst to substantiate decision making in the planning stage itself for future projects in similar contexts.

Keywords: catalysts, COEX, M.I.C.E., urban transformations

Procedia PDF Downloads 147

Authors: Meryam Labyad, Karima Fakiri, Widad Lahmini, Ghizlane Draiss, Mohamed Bouskraoui, Nadia Ouzennou

Abstract:

Background: Asthma is the most common chronic disease in children, affecting nearly 235 million people worldwide (OMS). In Morocco, asthma is much more common in children than in adults; the prevalence rate in children between 13 and 14 years of age is 20%.1 This pathology is marked by high morbidity, a significant impact on the quality of life and development of children 2 This requires a rigorous management strategy in order to achieve clinical control and reduce any risk to the patient 3 A search for aggravating factors is mandatory if a child has difficulty maintaining good asthma control. The objective of the present study is to describe asthma control during this confinement period in children aged 4 to 11 years followed by a pneumo-paediatric consultation. For children whose asthma is not controlled, a search for associations with promoting factors and adherence to treatment is also among the objectives of the study. Knowing the level of asthma control and influencing factors is a therapeutic priority in order to reduce hospitalizations and emergency care use. Objective: To assess asthma control and determine the factors influencing asthma levels in children with asthma during confinement following the COVID 19 pandemic. Method: Prospective cross-sectional study by questionnaire and structured interview among 66 asthmatic children followed in pediatric pneumology consultation at the CHU MED VI of Marrakech from 13/06/2020 to 13/07/2020, asthma control was assessed by the Childhood Asthma Control Test (C-ACT). Results: 66 children and their parents were included (mean age is 7.5 years), asthma was associated with allergic rhinitis (13.5% of cases), conjunctivitis (9% of cases), eczema (12% of cases), occurrence of infection (10.5% of cases). The period of confinement was marked by a decrease in the number of asthma attacks translated by a decrease in the number of emergency room visits (7.5%) of these asthmatic children, control was well controlled in 71% of the children, this control was significantly associated with good adherence to treatment (p<0.001), no infection (p<0.001) and no conjunctivitis (p=002) or rhinitis (p<0.001). This improvement in asthma control during confinement can be explained by the measures taken in the Kingdom to prevent the spread of COVID 19 (school closures, reduction in industrial activity, fewer means of transport, etc.), leading to a decrease in children's exposure to triggers, which justifies the decrease in the number of children having had an infection, allergic rhinitis or conjunctivitis during this period. In addition, the close monitoring of parents resulted in better therapeutic adherence (42.4% were fully observant). Confinement was positively perceived by 68% of the parents; this perception is significantly associated with the level of asthma control (p<0.001). Conclusion: Maintaining good control can be achieved through improved therapeutic adherence and avoidance of triggers, both of which were achieved during the containment period following the VIDOC pandemic 19.

Keywords: Asthma, control , COVID-19 , children

Procedia PDF Downloads 171

Authors: Sukhdev Singh, Baljinder Singh Bal, Amandeep Singh, Kanchan Thappa

Abstract:

A nation's future almost certainly rests on the future of its children, and a nation's wellbeing can be greatly improved by providing for the right upbringing of its children. Participating in physical education and sports programmes is crucial for reaching one's full potential. As we are all aware, sports have recently become incredibly popular on a global scale. Sports are continually becoming more and more popular, and this positive trend is probably going to last for some time to come. Motor abilities will provide more accurate information on the developmental process of children. Motor fitness is a component of physical fitness that includes strength, speed, flexibility, and agility, and is related to enhanced performance and the development of motor skills. In recent years, there has been increased interest in the differences in child growth between urban and rural environments. Differences in student growth, body dimensions, body composition, and fitness levels due to urban and rural environmental disparities have come into focus in recent years. The main aim of this study is to know the differentials of motor fitness components among the school children of rural and urban areas of the Jammu region. Material and Methods: In total, sixty male subjects (mean ± SD; age, 16.475 ± 1.0124 yrs.; height, 172.8 ± 2.0153 cm; Weight, 59.75 ± 3.628 kg) from the Jammu region took part in the study. A minimum sample size of 40 subjects was obtained and was derived from Rural (N1=20) and Urban (N2=20) school-going children. Statistical Applications: The Statistical Package for the Social Sciences (SPSS) version 14.0 was used for all analyses. The differences in the mean of each group for the selected variable were tested for the significance of difference by an independent samples t-test. For testing the hypotheses, the level of significance was set at 0.05. Results: Results revealed that there were significant differences of leg explosive strength (p=0.0040*), dynamic balance (p=0.0056*), and Agility (p=0.0176*) among the School Children of the rural and urban areas of the Jammu region. However, Results further revealed that there were not significant differences of cardio respiratory endurance (p=0.8612), speed (p=0.2231), Low Back/Hamstring Flexibility (p=0.6478), and Two Hand Coordination. (p= 0.0953) among the School Children of the rural and urban areas of the Jammu region. Conclusion: The results of study showed that there is significance difference between Rural and Urban School children of the Jammu region with regards to a variable," leg explosive strength, dynamic balance, Agility” and the there is no significance difference between Rural and Urban School children of the Jammu region with regards variable “cardio-respiratory endurance, speed, Low Back/Hamstring Flexibility, Two Hand Coordination”.

Keywords: motor fitness, rural areas, school children, urban areas

Procedia PDF Downloads 70

Authors: Barrera C. Monserrat, Sierra-Alvarez Reyes, Pat-Espadas Aurora, Moreno Andrade Ivan

Abstract:

Antimony is a toxic and carcinogenic metalloid considered a pollutant of priority interest by the United States Environmental Protection Agency. It is present in the environment in two oxidation states: antimonite (Sb (III)) and antimony (Sb (V)). Sb (III) is toxic to several aquatic organisms, but the potential inhibitory effect of Sb species for microorganisms has not been extensively evaluated. The fate and possible toxic impact of antimony on aerobic and anaerobic wastewater treatment systems are unknown. For this reason, the objective of this study was to evaluate the microbial toxicity of Sb (V) and Sb (III) in aerobic and anaerobic environments. Sb(V) and Sb(III) were used as potassium hexahydroxoantimonate (V) and potassium antimony tartrate, respectively (Sigma-Aldrich). The toxic effect of both Sb species in anaerobic environments was evaluated on methanogenic activity and the inhibition of hydrogen production of microorganisms from a wastewater treatment bioreactor. For the methanogenic activity, batch experiments were carried out in 160 mL serological bottles; each bottle contained basal mineral medium (100 mL), inoculum (1.5 g of VSS/L), acetate (2.56 g/L) as substrate, and variable concentrations of Sb (V) or Sb (III). Duplicate bioassays were incubated at 30 ± 2°C on an orbital shaker (105 rpm) in the dark. Methane production was monitored by gas chromatography. The hydrogen production inhibition tests were carried out in glass bottles with a working volume of 0.36 L. Glucose (50 g/L) was used as a substrate, pretreated inoculum (5 g VSS/L), mineral medium and varying concentrations of the two species of antimony. The bottles were kept under stirring and at a temperature of 35°C in an AMPTSII device that recorded hydrogen production. The toxicity of Sb on aerobic microorganisms (from a wastewater activated sludge treatment plant) was tested with a Microtox standardized toxicity test and respirometry. Results showed that Sb (III) is more toxic than Sb (V) for methanogenic microorganisms. Sb (V) caused a 50% decrease in methanogenic activity at 250 mg/L. In contrast, exposure to Sb (III) resulted in a 50% inhibition at a concentration of only 11 mg/L, and an almost complete inhibition (95%) at 25 mg/L. For hydrogen-producing microorganisms, Sb (III) and Sb (V) inhibited 50% of this production with 12.6 mg/L and 87.7 mg/L, respectively. The results for aerobic environments showed that 500 mg/L of Sb (V) do not inhibit the Allivibrio fischeri (Microtox) activity or specific oxygen uptake rate of activated sludge. In the case of Sb (III), this caused a loss of 50% of the respiration of the microorganisms at concentrations below 40 mg/L. The results obtained indicate that the toxicity of the antimony will depend on the speciation of this metalloid and that Sb (III) has a significantly higher inhibitory potential compared to Sb (V). It was shown that anaerobic microorganisms can reduce Sb (V) to Sb (III). Acknowledgments: This work was funded in part by grants from the UA-CONACYT Binational Consortium for the Regional Scientific Development and Innovation (CAZMEX), the National Institute of Health (NIH ES- 04940), and PAPIIT-DGAPA-UNAM (IN105220).

Keywords: aerobic inhibition, antimony reduction, hydrogen inhibition, methanogenic toxicity

Procedia PDF Downloads 147

Authors: Otgonjargal Damdinbaljir

Abstract:

Background: Infant feeding practices have a major role in determining the nutritional status of children and are associated with household socioeconomic and demographic factors. In 2010, Mongolia used WHO 2008 edition of Indicators for assessing infant and young child feeding practices for the first time. Objective: To evaluate the feeding status of infants and young children under 2 years old in Mongolia. Materials and Methods: The study was conducted by cluster random sampling. The data on breastfeeding and complementary food supplement of the 350 infants and young children aged 0-23 months in 21 provinces of the 4 economic regions of the country and capital Ulaanbaatar city were collected through questionnaires. The feeding status was analyzed according to the WHO 2008 edition of Indicators for assessing infant and young child feeding practices. Analysis of data: Survey data was analysed using the PASW statistics 18.0 and EPI INFO 2000 software. For calculation of overall measures for the entire survey sample, analyses were stratified by region. Age-specific feeding patterns were described using frequencies, proportions and survival analysis. Logistic regression was done with feeding practice as dependent and socio demographic factors as independent variables. Simple proportions were calculated for each IYCF indicator. The differences in the feeding practices between sexes and age-groups, if any, were noted using chi-square test. Ethics: The Ethics Committee under the auspices of the Ministry of Health approved the study. Results: A total of 350 children aged 0-23 months were investigated. The rate of ever breastfeeding of children aged 0-23 months reached up to 98.2%, while the percentage of early initiation of breastfeeding was only 85.5%. The rates of exclusive breastfeeding under 6 months, continued breastfeeding for 1 year, and continued breastfeeding for 2 years were 71.3%, 74% and 54.6%, respectively. The median time of giving complementary food was the 6th month and the weaning time was the 9th month. The rate of complementary food supplemented from 6th-8th month in time was 80.3%. The rates of minimum dietary diversity, minimum meal frequency, and consumption of iron-rich or iron-fortified foods among children aged 6-23 months were 52.1%, 80.8% (663/813) and 30.1%, respectively. Conclusions: The main problems revealed from the study were inadequate category and frequency of complementary food, and the low rate of consumption of iron-rich or iron-fortified foods were the main issues to be concerned on infant feeding in Mongolia. Our findings have highlighted the need to encourage mothers to enrich their traditional wheat- based complementary foods add more animal source foods and vegetables.

Keywords: complementary feeding, early initiation of breastfeeding, exclusive breastfeeding, minimum meal frequency

Procedia PDF Downloads 463

Authors: Anil K. Giri, Dipak Subedi, Kathleen Kassel, Ashok Mishra

Abstract:

The United States Department of Agriculture’s programs has been accused of being discriminatory in the past based on the race of the farmer, especially African-American producers. This study examines if there was racial discrimination in payments from the most recent new USDA programs, including those made in response to the pandemic. This study uses the Analysis of Variance (ANOVA) to examine the payments after normalizing them relative to cash receipts to test if discrimination in the number of payments received exists. Three programs investigated in this study are: i) the Coronavirus Food Assistance Program (CFAP), ii) the Market Facilitation Program (MFP), and (iii) the Paycheck Protection Program (PPP). The PPP program was administered by the Small Business Administration, whereas the other two were designed and implemented by the USDA. The PPP made forgivable loans to small businesses and, initially, was heavily criticized for not reaching minority businesses (in general). The Small Business Administration then initiated a second draw of PPP loans, prioritizing minority-owned businesses. This study compares attributes of PPP loans made to African-American farming businesses and other farming businesses in the two draws of the PPP. We find that the number of African-American farming businesses participating in the second draw of PPP loans decreased significantly from the first draw. However, the average amount of PPP loans to African-American farming businesses increased in the second draw. In the first draw, the average cost of jobs reported per loan was higher for African-American farming businesses than for other producers. In the second draw, the average cost of jobs reported per loan was significantly higher for other farming businesses than for African-American businesses. The share of PPP loans forgiven for African-American farming businesses is significantly below the national rate of 89 percent. The rate of forgiveness for PPP loans made to African-American producers is unlikely to increase significantly without policy changes. This can increase financial burdens in the future to farm operations operated by African- Americans. Finally, we conclude that the initial goal of increasing minority participation in PPP loans in the second draw, at least among African-Americans in the agricultural sector, did not meet. CFAP made almost $600 million in direct payments to minority producers, including Black producers. Black or African American producers received more than $52 million in CFAP payments. CFAP payments were proportional to the value of agricultural commodities sold for most minority producers. The 2017 Census of Agriculture showed that the majority of minority producers, including African American producers but excluding Asian producers, raised livestock. CFAP made the highest payments to livestock minority producers.

Keywords: United States department of agriculture (USDA), coronavirus food assistance program (CFAP), paycheck protection program (PPP), African-American producers, minority American producers

Procedia PDF Downloads 84

Authors: Candy Chieh Lee

Abstract:

Objective: The purpose of this study is to investigate the relationship between visual perception and social function in patients with schizophrenia. The specific aims are: 1) To explore performances in visual perception and social function in patients with schizophrenia 2) to examine the correlation between visual perceptual skills and social function in patients with schizophrenia The long-term goal is to be able to provide the most adequate intervention program for promoting patients’ visual perceptual skills and social function, as well as compensatory techniques. Background: Perceptual deficits in schizophrenia have been well documented in the visual system. Clinically, a considerable portion (up to 60%) of schizophrenia patients report distorted visual experiences such as visual perception of motion, color, size, and facial expression. Visual perception is required for the successful performance of most activities of daily living, such as dressing, making a cup of tea, driving a car and reading. On the other hand, patients with schizophrenia usually exhibit psychotic symptoms such as auditory hallucination and delusions which tend to alter their perception of reality and affect their quality of interpersonal relationship and limit their participation in various social situations. Social function plays an important role in the prognosis of patients with schizophrenia; lower social functioning skills can lead to poorer prognosis. Investigations on the relationship between social functioning and perceptual ability in patients with schizophrenia are relatively new but important as the results could provide information for effective intervention on visual perception and social functioning in patients with schizophrenia. Methods: We recruited 50 participants with schizophrenia in the mental health hospital (Taipei City Hospital, Songde branch, Taipei, Taiwan) acute ward. Participants who have signed consent forms, diagnosis of schizophrenia and having no organic vision deficits were included. Participants were administered the test of visual-perceptual skills (non-motor), third edition (TVPS-3) and the personal and social performance scale (PSP) for assessing visual perceptual skill and social function. The assessments will take about 70-90 minutes to complete. Data Analysis: The IBM SPSS 21.0 will be used to perform the statistical analysis. First, descriptive statistics will be performed to describe the characteristics and performance of the participants. Lastly, Pearson correlation will be computed to examine the correlation between PSP and TVPS-3 scores. Results: Significant differences were found between the means of participants’ TVPS-3 raw scores of each subtest with the age equivalent raw score provided by the TVPS-3 manual. Significant correlations were found between all 7 subtests of TVPS-3 and PSP total score. Conclusions: The results showed that patients with schizophrenia do exhibit visual perceptual deficits and is correlated social functions. Understanding these facts of patients with schizophrenia can assist health care professionals in designing and implementing adequate rehabilitative treatment according to patients’ needs.

Keywords: occupational therapy, social function, schizophrenia, visual perception

Procedia PDF Downloads 127

Authors: Armin Solemanifar, Arthur Wilkinson, Kinjalkumar Patel

Abstract:

Carbon fibre (CF) - polymer laminate composites have very low densities (approximately 40% lower than aluminium), high strength and high stiffness but in terms of toughness properties they often require modifications. For example, adding rubbers or thermoplastics toughening agents are common ways of improving the interlaminar fracture toughness of initially brittle thermoset composite matrices. The main aim of this project was to toughen CF-epoxy resin laminate composites using hybrid CF-fabrics incorporating Innegra™ a commercial highly-oriented polypropylene (PP) fibre, in which more than 90% of its crystal orientation is parallel to the fibre axis. In this study, the damage tolerance of hybrid (carbon-Innegra, CI) composites was investigated. Laminate composites were produced by resin-infusion using: pure CF fabric; fabrics with different ratios of commingled CI, and two different types of pure Innegra fabrics (Innegra 1 and Innegra 2). Dynamic mechanical thermal analysis (DMTA) was used to measure the glass transition temperature (Tg) of the composite matrix and values of flexural storage modulus versus temperature. Mechanical testing included drop-weight impact, compression-after-impact (CAI), and interlaminar (short-beam) shear strength (ILSS). Ultrasonic C-Scan imaging was used to determine the impact damage area and scanning electron microscopy (SEM) to observe the fracture mechanisms that occur during failure of the composites. For all composites, 8 layers of fabrics were used with a quasi-isotropic sequence of [-45°, 0°, +45°, 90°]s. DMTA showed the Tg of all composites to be approximately same (123 ±3°C) and that flexural storage modulus (before the onset of Tg) was the highest for the pure CF composite while the lowest were for the Innegra 1 and 2 composites. Short-beam shear strength of the commingled composites was higher than other composites, while for Innegra 1 and 2 composites only inelastic deformation failure was observed during the short-beam test. During impact, the Innegra 1 composite withstood up to 40 J without any perforation while for the CF perforation occurred at 10 J. The rate of reduction in compression strength upon increasing the impact energy was lowest for the Innegra 1 and 2 composites, while CF showed the highest rate. On the other hand, the compressive strength of the CF composite was highest of all the composites at all impacted energy levels. The predominant failure modes for Innegra composites observed in cross-sections of fractured specimens were fibre pull-out, micro-buckling, and fibre plastic deformation; while fibre breakage and matrix delamination were a major failure observed in the commingled composites due to the more brittle behaviour of CF. Thus, Innegra fibres toughened the CF composites but only at the expense of reducing compressive strength.

Keywords: hybrid composite, thermoplastic fibre, compression strength, damage tolerance

Procedia PDF Downloads 284

Authors: Kraiem Khadija, Hamadi Kallali, Naceur Jedidi

Abstract:

Constructed wetland systems are eco-technology recognized as environmentally friendly and emerging innovative solutions remediation as these systems are cost-effective and sustainable wastewater treatment systems. The performance of these biological system is affected by various factors such as plant, substrate, wastewater type, hydraulic loading rate, hydraulic retention time, water depth, and operation mood. The objective of this study was to to assess the alters of plant species on pollutants reduction and enrichment of anammox and nitrifing denitrifing bacteria in a modified vertical flow (VFCW) constructed wetland. This tests were carried out using three modified vertical constructed wetlands with a surface of 0.23 m² and depth 80 cm. It was a saturated vertical constructed wetland at the bottom. The saturation zone is maintained by the siphon structure at the outlet. The VFCW (₁) system was unplanted, VFCW (₂) planted with Typha angustofolia, and VFCW(₃) planted with Phragmites australis. The experimental units were fed with domestic wastewater and were operated by batch mode during 8 months at an average hydraulic loading rate around 20 cm day− 1. The operation cycle was two days feeding and five days rest. Results indicated that plants presence improved the removal efficiency; the removal rates of organic matter (85.1–90.9%; COD and 81.8–88.9%; BOD5), nitrogen (54.2–73%; NTK and 66–77%; NH4 -N) were higher by 10.7–30.1% compared to the unplanted vertical constructed wetland. On the other hand, the plant species had no significant effect on removal efficiency of COD, The removal of COD was similar in VFCW (₂) and VFCW (₃) (p > 0.05), attaining average removal efficiencies of 88.7% and 85.2%, respectively. Whereas it had a significant effect on NTK removal (p > 0.05), with an average removal rate of 72% versus 51% for VFCW (₂) and VFCW (₃), respectively. Among the three sets of vertical flow constructed wetlands, the VFCW(₂) removed the highest percent of total streptococcus, fecal streptococcus total coliforms, fecal coliforms, E. coli as 59, 62, 52, 63, and 58%, respectively. The presence and the plant species alters the community composition and abundance of the bacteria. The abundance of bacteria in the planted wetland was much higher than that in the unplanted one. VFCW(₃) had the highest relative abundance of nitrifying bacteria such as Nitrosospira (18%), Nitrosospira (12%), and Nitrobacter (8%). Whereas the vertical constructed wetland planted with typha had larger number of denitrifying species, with relative abundances of Aeromonas (13%), Paracoccus (11%), Thauera (7%), and Thiobacillus (6%). However, the abundance of nitrifying bacteria was very lower in this system than VFCW(₂). Interestingly, the presence of Thypha angustofolia species favored the enrichment of anammox bacteria compared to unplanted system and system planted with phragmites australis. The results showed that the middle layer had the most accumulation of anammox bacteria, which the anaerobic condition is better and the root system is moderate. Vegetation has several characteristics that make it an essential component of wetlands, but its exact effects are complex and debated.

Keywords: wastawater, constructed wetland, anammox, removal

Procedia PDF Downloads 90

Authors: Yasser R. Shaban

Abstract:

A practical multipurpose device for medical isotopes production is most wanted for clinical centers and researches. Unfortunately, the major supply of these radioisotopes currently comes from aging sources, and there is a great deal of uneasiness in the domestic market. There are also many cases where the cost of certain radioisotopes is too high for their introduction on a commercial scale even though the isotopes might have great benefits for society. The medical isotopes such as radiotracers PET (Positron Emission Tomography), Technetium-99 m, and Iodine-131, Lutetium-177 by is feasible to be generated by a single unit named IEMC (Inertial Electrostatic Magnetic Confinement). The IEMC fusion vessel is the upgrading unit of the Inertial Electrostatic Confinement IEC fusion vessel. Comprehensive experimental works on IEC were carried earlier with promising results. The principle of inertial electrostatic magnetic confinement IEMC fusion is based on forcing the binary fuel ions to interact in the opposite directions in ions cyclotrons orbits with different kinetic energies in order to have equal compression (forces) and with different ion cyclotron frequency ω in order to increase the rate of intersection. The IEMC features greater fusion volume than IEC by several orders of magnitude. The particles rate from the IEMC approach are projected to be 8.5 x 10¹¹ (p/s), ~ 0.2 microampere proton, for D/He-3 fusion reaction and 4.2 x 10¹² (n/s) for D/T fusion reaction. The projected values of particles yield (neutrons and protons) are suitable for medical isotope productions on-site by a single unit without any change in the fusion vessel but only the fuel gas. The PET radiotracers are usually produced on-site by medical ion accelerator whereas Technetium-99m (Tc-99m) is usually produced off-site from the irradiation facilities of nuclear power plants. Typically, hospitals receive molybdenum-99 isotope container; the isotope decays to Tc-99mwith half-life time 2.75 days. Even though the projected current from IEMC is lesser than the proton current from the medical ion accelerator but still the IEMC vessel is simpler, and reduced in components and power consumption which add a new value of populating the PET radiotracers in most clinical centers. On the other hand, the projected neutrons flux from the IEMC is lesser than the thermal neutron flux at the irradiation facilities of nuclear power plants, but in the IEMC case the productions of Technetium-99m is suggested to be at the resonance region of which the resonance integral cross section is two orders of magnitude higher than the thermal flux. Thus it can be said the net activity from both is evened. Besides, the particle accelerator cannot be considered a multipurpose particles production unless a significant change is made to the accelerator to change from neutrons mode to protons mode or vice versa. In conclusion, the projected fusion yield from IEMC is a straightforward since slightly change in the primer IEC and ion source is required.

Keywords: electrostatic versus magnetic confinement fusion vessel, ion source, medical isotopes productions, neutron activation

Procedia PDF Downloads 332

Authors: Ofelia Loani Elvir Lazo, Roya Yumul, David Chernobylsky, Omar Durra

Abstract:

Background: It is crucial to detect the patient’s existing anxiety to assist patients in a perioperative setting which is to be caused by the fear associated with surgical and anesthetic complications. However, the current gold standard for assessing patient anxiety, the STAI, is problematic to use in the preoperative setting, given the duration and concentration required to complete the 40-item questionnaire. Our primary aim in the study is to investigate the correlation of the Yumul Visual Facial Anxiety Scale (VFAS) and Numerical Verbal Rating Scale (NVRS) to State-Trait Anxiety Inventory (STAI) to determine the optimal anxiety scale to use in the perioperative setting. Methods: A clinical study of patients undergoing various surgeries was conducted utilizing each of the preoperative anxiety scales. Inclusion criteria included patients undergoing elective surgeries, while exclusion criteria included patients with anesthesia contraindications, inability to comprehend instructions, impaired judgement, substance abuse history, and those pregnant or lactating. 293 patients were analyzed in terms of demographics, anxiety scale survey results, and anesthesia data via Spearman Coefficients, Chi-Squared Analysis, and Fischer’s exact test utilized for comparative analysis. Results: Statistical analysis showed that VFAS had a higher correlation to STAI than NVRS (rs=0.66, p<0.0001 vs. rs=0.64, p<0.0001). The combined VFAS-Categorization Scores showed the highest correlation with the gold standard (rs=0.72, p<0.0001). Subgroup analysis showed similar results. STAI evaluation time (247.7 ± 54.81 sec) far exceeds VFAS (7.29 ± 1.61 sec), NVRS (7.23 ± 1.60 sec), and Categorization scales (7.29 ± 1.99 sec). Patients preferred VFAS (54.4%), Categorization (11.6%), and NVRS (8.8%). Anesthesiologists preferred VFAS (63.9%), NVRS (22.1%), and Categorization Scales (14.0%). Of note, the top five causes of preoperative anxiety were determined to be waiting (56.5%), pain (42.5%), family concerns (40.5%), no information about surgery (40.1%), or anesthesia (31.6%). Conclusıons: Both VFAS and Categorization tests also take significantly less time than STAI, which is critical in the preoperative setting. Combined VFAS-Categorization Score (VCS) demonstrates the highest correlation to the gold standard, STAI. Among both patients and anesthesiologists, VFAS was the most preferred scale. This forms the basis of the Yumul Faces Anxiety Scale, designed for quick quantization and assessment in the preoperative setting while maintaining a high correlation to the golden standard. Additional studies using the formulated Yumul Faces Anxiety Scale are merited.

Keywords: numerical verbal anxiety scale, preoperative anxiety, state-trait anxiety inventory, visual facial anxiety scale

Procedia PDF Downloads 106

Authors: Awol Mekonnen, Temesgen Sidamo, Epherm Engdawork, Kaleab Asresb

Abstract:

Ethnopharmacological Relevance: The leaves of Kalanchoe petitiana A. Rich (Crassulaceae) are used in Ethiopian folk medicine for treatment of evil eye, fractured surface for bone setting and several skin disorders including for the treatment of sores, boils, and malignant wounds. Aim of the Study: In order to scientifically prove the claimed utilization of the plant, the effects of the extracts and the fractions were investigated using in vivo excision, incision and dead space wound models. Materials and Method: Mice were used for wound healing study, while rats and rabbit were used for skin irritation test. For studying healing activity, 80% methanolic extract and the fractions were formulated in strength of 5% and 10%, either as ointment (hydroalcoholic extract, aqueous and methanol fractions) or gel (chloroform fraction). Oral administration of the crude extract was used for dead space model. Negative controls were treated either with simple ointment or sodium carboxyl methyl cellulose xerogel, while positive controls were treated with nitrofurazone (0.2 w/v) skin ointment. Negative controls for dead space model were treated with 1% carboxy methyl cellulose. Parameters, including rate of wound contraction, period of complete epithelializtion, hydroxyproline contents and skin breaking strength were evaluated. Results: Significant wound healing activity was observed with ointment formulated from the crude extract at both 5% and 10% concentration (p<0.01) compared to controls in both excision and incision models. In dead space model, 600 mg/kg (p<0.01), but not 300 mg/kg, significantly increased hydroxyproline content. Fractions showed variable effect, with the chloroform fraction lacking any significant effect. Both 5% and 10% formulations of the aqueous and methanolic fractions significantly increased wound contraction, decreased epithelializtion time and increased hydroxyproline content in excision wound model (p<0.05) as compared to controls. These fractions were also endowed with higher skin breaking strength in incision wound model (p<0.01). Conclusions: The present study provided evidence that the leaves of Kalanchoe petitiana A. Rich possess remarkable wound healing activities supporting the folkloric assertion of the plant. Fractionation revealed that polar or semi-polar compound may play vital role, as both aqueous and methanolic fractions were endowed with wound healing activity.

Keywords: wound healing, Kalanchoae petitiana, excision wound, incision wound, dead space model

Procedia PDF Downloads 292

Authors: Gabriel Ugalahi, Dominic S. Nyitamen

Abstract:

This project seeks to improve Wi-Fi reception by utilizing the properties of directional microstrip patch antennae. Where there is a dense population of Wi-Fi signal, several signal sources transmitting on the same frequency band and indeed channel constitutes interference to each other. The time it takes for request to be received, resolved and response given between a user and the resource provider is increased considerably. By deploying a directional patch antenna with a narrow bandwidth, the range of frequency received is reduced and should help in limiting the reception of signal from unwanted sources. A rectangular microstrip patch antenna (RMPA) is designed to operate at the Industrial Scientific and Medical (ISM) band (2.4GHz) commonly used in Wi-Fi network deployment. The dimensions of the antenna are calculated and these dimensions are used to generate a model on Advanced Design System (ADS), a microwave simulator. Simulation results are then analyzed and necessary optimization is carried out to further enhance the radiation quality so as to achieve desired results. Impedance matching at 50Ω is also obtained by using the inset feed method. Final antenna dimensions obtained after simulation and optimization are then used to implement practical construction on an FR-4 double sided copper clad printed circuit board (PCB) through a chemical etching process using ferric chloride (Fe2Cl). Simulation results show an RMPA operating at a centre frequency of 2.4GHz with a bandwidth of 40MHz. A voltage standing wave ratio (VSWR) of 1.0725 is recorded on a return loss of -29.112dB at input port showing an appreciable match in impedance to a source of 50Ω. In addition, a gain of 3.23dBi and directivity of 6.4dBi is observed during far-field analysis. On deployment, signal reception from wireless devices is improved due to antenna gain. A test source with a received signal strength indication (RSSI) of -80dBm without antenna installed on the receiver was improved to an RSSI of -61dBm. In addition, the directional radiation property of the RMPA prioritizes signals by pointing in the direction of a preferred signal source thus, reducing interference from undesired signal sources. This was observed during testing as rotation of the antenna on its axis resulted to the gain of signal in-front of the patch and fading of signals away from the front.

Keywords: advanced design system (ADS), inset feed, received signal strength indicator (RSSI), rectangular microstrip patch antenna (RMPA), voltage standing wave ratio (VSWR), wireless fidelity (Wi-Fi)

Procedia PDF Downloads 205

Authors: Faris Mohsin Alabeedi

Abstract:

Pemphigus Vulgaris (PV) is a life-threatening autoimmune blistering disease characterized by the presence of autoantibodies directed against the epidermis's surface proteins. There are two forms of PV, mucocutaneous and mucosal-dominant PV. Disruption of the cell junctions is a hallmark of PV due to the autoantibodies targeting the desmosomal cadherins, desmoglein-3 (Dsg3) and desmoglein-1, leading to acantholysis in the skin and mucous membrane. Although the pathogenesis of PV is known, the detailed molecular events remain not fully understood. Our recent study has shown that both the PV sera and pathogenic anti-Dsg3 antibody AK23 can induce ROS and cause oxidative stress in cultured keratinocytes. In line with our finding, other independent studies also demonstrate oxidative stress in PV. Since Nrf2 plays a crucial role in cellular anti-oxidative stress response, we hypothesize that the expression of Nrf2 may alter in PV. Thus, treatment of cells with PV sera or AK23 may cause changes in Nrf2 expression and distribution. The purpose of this study was to examine the effect of AK23 and PV sera on Nrf2 in a normal human keratinocyte cell line, such as NTERT cells. Both a time-course and dose-dependent experiments with AK23, alongside the matched isotype control IgG, were performed in keratinocyte cultures and analysed by immunofluorescence for Nrf2 and Dsg3. Additionally, the same approach was conducted with the sera from PV patients and healthy individuals that served as a control in this study. All the fluorescent images were analysed using ImageJ software. Each experiment was repeated twice. In general, variations were observed throughout this study. In the dose-response experiments, although enhanced Dsg3 expression was consistently detected in AK23 treated cells, the expression of Nrf2 showed no consistent findings between the experiments, although changes in its expression were noticeable in cells treated with AK23. In the time-course study, a trend with induction of Nrf2 over time was shown in control cells treated with mouse isotype IgG. Treatment with AK23 showed a reduction of Nrf2 in a time-dependent manner, especially at the 24-hour time point. However, the earlier time points, such as 2 hours and 6 hours with AK23 treatments, detected somewhat variations. Finally, PV sera caused a decrease of Dsg3, but on the other hand, variations were observed in Nrf2 expression in PV sera treated cells. In general, PV sera seemed to cause a reduction of Nrf2 in the majority of PV sera treated samples. In addition, more pronounced cytoplasmic expression of Nrf2 has been observed in PV sera treated cells than those treated with AK23, suggesting that polyclonal and monoclonal IgG might induce a different effect on Nrf2 expression and distribution. Further experimental studies are crucial to obtain a more coincide global view of Nrf2-mediated gene regulation. In particular, Pemphigus Voulgaris studies assessing how the Nrf2-dependent network changes from a physiological to a pathological condition can provide insight into disease mechanisms and perhaps initiate further treatment approaches.

Keywords: pemphigus vulgaris, monoclonal antibody against desmoglein-3, Nrf2 oxidative stress, keratinocyte cultures

Procedia PDF Downloads 68

Authors: Arsalan Jabbar, Wajiha Javed, Nelofer Mehboob, Zahid Memon

Abstract:

Introduction: There are multiple social, individual and cultural factors that influence an individual’s decision to adopt family planning methods especially among non-users in patriarchal societies like Pakistan.Non-users, if targeted efficiently, can contribute significantly to country’s CPR. A research study showed that non-users if convinced to adopt lactational amenorrhea method can shift to long-term methods in future. Research shows that if non-users are targeted efficiently a 59% reduction in unintended pregnancies in Saharan Africa and South-Central and South-East Asia is anticipated. Methods: We did secondary data analysis on Pakistan Demographic Heath Survey (2012-13) dataset. Use of contraception (never-use/ever-use) was the outcome variable. At univariate level Chi-square/Fisher Exact test was used to assess relationship of baseline covariates with contraception use. Then variables to be incorporated in the model were checked for multi-collinearity, confounding, and interaction. Then binary logistic regression (with an urban-rural stratification) was done to find the relationship between contraception use and baseline demographic and social variables. Results: The multivariate analyses of the study showed that younger women (≤ 29 years) were more prone to be never users as compared to those who were > 30 years and this trend was seen in urban areas (AOR 1.92, CI 1.453-2.536) as well as rural areas (AOR 1.809, CI 1.421-2.303). While looking at regional variation, women from urban Sindh (AOR 1.548, CI 1.142-2.099) and urban Balochistan (AOR 2.403, CI 1.504-3.839) had more never users as compared to other urban regions. Women in the rich wealth quintile were more never users and this was seen both in urban and rural localities (urban (AOR 1.106 CI .753-1.624); rural areas (AOR 1.162, CI .887-1.524)) even though these were not statistically significant. Women idealizing more children(> 4) are more never users as compared to those idealizing less children in both urban (AOR 1.854, CI 1.275-2.697) and rural areas (AOR 2.101, CI 1.514-2.916). Women who never lost a pregnancy were more inclined to be non-users in rural areas (AOR 1.394, CI 1.127-1.723) .Women familiar with only traditional or no method had more never users in rural areas (AOR 1.717, CI 1.127-1.723) but in urban areas it wasn’t significant. Women unaware of Lady Health Worker’s presence in their area were more never users especially in rural areas (AOR 1.276, CI 1.014-1.607). Women who did not visit any care provider were more never users (urban (AOR 11.738, CI 9.112-15.121) rural areas (AOR 7.832, CI 6.243-9.826)). Discussion/Conclusion: This study concluded that government, policy makers and private sector family planning programs should focus on the untapped pool of never users (younger women from underserved provinces, in higher wealth quintiles, who desire more children.). We need to make sure to cover catchment areas where there are less LHWs and less providers as ignorance to modern methods and never been visited by an LHW are important determinants of never use. This all is in sync with previous literate from similar developing countries.

Keywords: contraception, demographic and health survey, family planning, never users

Procedia PDF Downloads 398

Authors: Dalita G. S. M. Cavalcante, Elton A. P. dos Reis, Andressa S. Gomes, Caroline S. Danna, Leandra Ernest Kerche-Silva, Eidi Yoshihara, Aldo E. Job

Abstract:

In order to minimize environmental impacts, a composite was developed from mixture of leather shavings (LE) with natural rubber (NR), which patent is already deposited. The new material created can be used in applications such as floors e heels for shoes. Besides these applications, the aim is to use this new material for the production of products for the textile industry, such as boots, gloves and bags. But the question arises, as to biocompatibility of this new material. This is justified because the structure of the leather shavings has chrome. The trivalent chromium is usually not toxic, but the hexavalent chromium can be highly toxic and genotoxic for living beings, causing damage to the DNA molecule and contributing to the formation of cancer. Based on this, the objective of this study is evaluate the possible genotoxic effects of the new composite, using as system - test two cell lines (MRC-5 and CHO-K1) by comet assay. For this, the production of the composite was performed in three proportions: for every 100 grams of NR was added 40 (E40), 50 (E50) or 60 (E60) grams of LE. The latex was collected from the rubber tree (Hevea brasiliensis). For vulcanization of the NR, activators and accelerators were used. The two cell lines were exposed to the new composite in its three proportions using elution method, that is, cells exposed to liquid extracts obtained from the composite for 24 hours. For obtaining the liquid extract, each sample of the composite was crushed into pieces and mixed with an extraction solution. The quantification of total chromium and hexavalent chromium in the extracts were performed by Optical Emission Spectrometry by Inductively Coupled Plasma (ICP-OES). The levels of DNA damage in cells exposed to both extracts were monitored by alkaline version of the comet assay. The results of the quantification of metals in ICP-OES indicated the presence of total chromium in different extracts, but were not detected presence of hexavalent chromium in any extract. Through the comet assay were not found DNA damage of the CHO-K1 cells exposed to both extracts. As for MRC-5, was found a significant increase in DNA damage in cells exposed to E50 and E60. Based on the above data, it can be asserted that the extracts obtained from the composite were highly genotoxic for MRC-5 cells. These biological responses do not appear to be related to chromium metal, since there was a predominance of trivalent chromium in the extracts, indicating that during the production process of the new composite, there was no formation of hexavalent chromium. In conclusion it can infer that the leather shavings containing chromium can be reused, thereby reducing the environmental impacts of this waste. Already on the composite indicates to its incorporation in applications that do not aim at direct contact with the human skin, and it is suggested the chain of composite production be studied, in an attempt to make it biocompatible so that it may be safely used by the textile industry.

Keywords: cell line, chrome, genotoxicity, leather, natural rubber

Procedia PDF Downloads 187

Authors: Anitha Muralidhara, Victor Engelen, Christophe Len, Pascal Pandard, Guy Marlair

Abstract:

Production of bio-based chemicals and materials from lignocellulosic biomass is gaining tremendous importance in advanced bio-refineries while aiming towards progressive replacement of petroleum based chemicals in transportation fuels and commodity polymers. One such attempt has resulted in the production of key furan derivatives (FD) such as furfural, HMF, MMF etc., via acid catalyzed dehydration (ACD) of C6 and C5 sugars, which are further converted into key chemicals or intermediates (such as Furandicarboxylic acid, Furfuryl alcohol etc.,). In subsequent processes, many high potential FD are produced, that can be converted into high added value polymers or high energy density biofuels. During ACD, an unavoidable polyfuranic byproduct is generated which is called humins. The family of FD is very large with varying chemical structures and diverse physicochemical properties. Accordingly, the associated risk profiles may largely vary. Hazardous Material (Haz-mat) classification systems such as GHS (CLP in the EU) and the UN TDG Model Regulations for transport of dangerous goods are one of the preliminary requirements for all chemicals for their appropriate classification, labelling, packaging, safe storage, and transportation. Considering the growing application routes of FD, it becomes important to notice the limited access to safety related information (safety data sheets available only for famous compounds such as HMF, furfural etc.,) in these internationally recognized haz-mat classification systems. However, these classifications do not necessarily provide information about the extent of risk involved when the chemical is used in any specific application. Factors such as thermal stability, speed of combustion, chemical incompatibilities, etc., can equally influence the safety profile of a compound, that are clearly out of the scope of any haz-mat classification system. Irrespective of the bio-based origin, FD has so far received inconsistent remarks concerning their toxicity profiles. With such inconsistencies, there is a fear that, a large family of FD may also follow extreme judgmental scenarios like ionic liquids, by ranking some compounds as extremely thermally stable, non-flammable, etc., Unless clarified, these messages could lead to misleading judgements while ranking the chemical based on its hazard rating. Safety is a key aspect in any sustainable biorefinery operation/facility, which is often underscored or neglected. To fill up these existing data gaps and to address ambiguities and discrepancies, the current study focuses on giving preliminary insights on safety assessment of FD and their potential targeted by-products. With the available information in the literature and obtained experimental results, physicochemical safety, environmental safety as well as (a scenario based) fire safety profiles of key FD, as well as side streams such as humins and levulinic acid, will be considered. With this, the study focuses on defining patterns and trends that gives coherent safety related information for existing and newly synthesized FD in the market for better functionality and sustainable applications.

Keywords: furanics, humins, safety, thermal and fire hazard, toxicity

Procedia PDF Downloads 159

Authors: S. V. Kuznetsov, M. N. Mayakova, V. Yu. Proydakova, V. V. Pavlov, A. S. Nizamutdinov, O. A. Morozov, V. V. Voronov, P. P. Fedorov

Abstract:

Increase in the share of electricity received by conversion of solar energy results in the reduction of the industrial impact on the environment from the use of the hydrocarbon energy sources. One way to increase said share is to improve the efficiency of solar energy conversion in silicon-based solar panels. Such efficiency increase can be achieved by transferring energy from sunlight-insensitive areas of work of silicon solar panels to the area of their photoresistivity. To achieve this goal, a transition to new luminescent materials with the high quantum yield of luminescence is necessary. Improvement in the quantum yield can be achieved by quantum cutting, which allows obtaining a quantum yield of down conversion of more than 150% due to the splitting of high-energy photons of the UV spectral range into lower-energy photons of the visible and near infrared spectral ranges. The goal of present work is to test approach of excitation through sensibilization of 4f-4f fluorescence of Yb3+ by various RE ions absorbing in UV and Vis spectral ranges. One of promising materials for quantum cutting luminophores are fluorides. In our investigation we have developed synthesis of nano- and submicron powders of calcium fluoride and strontium doped with rare-earth elements (Yb: Ce, Yb: Pr, Yb: Eu) of controlled dimensions and shape by co-precipitation from water solution technique. We have used Ca(NO3)2*4H2O, Sr(NO3)2, HF, NH4F as precursors. After initial solutions of nitrates were prepared they have been mixed with fluorine containing solution by dropwise manner. According to XRD data, the synthesis resulted in single phase samples with fluorite structure. By means of SEM measurements, we have confirmed spherical morphology and have determined sizes of particles (50-100 nm after synthesis and 150-300 nm after calcination). Temperature of calcination appeared to be 600°C. We have investigated the spectral-kinetic characteristics of above mentioned compounds. Here the diffuse reflection and laser induced fluorescence spectra of Yb3+ ions excited at around 4f-4f and 4f-5d transitions of Pr3+, Eu3+ and Ce3+ ions in the synthesized powders are reported. The investigation of down conversion luminescence capability of synthesized compounds included measurements of fluorescence decays and quantum yield of 2F5/2-2F7/2 fluorescence of Yb3+ ions as function of Yb3+ and sensitizer contents. An optimal chemical composition of CaF2-YbF3- LnF3 (Ln=Ce, Eu, Pr), SrF2-YbF3-LnF3 (Ln=Ce, Eu, Pr) micro- and nano- powders according to criteria of maximal IR fluorescence yield is proposed. We suppose that investigated materials are prospective in solar panels improvement applications. Work was supported by Russian Science Foundation grant #17-73- 20352.

Keywords: solar cell, fluorides, down-conversion luminescence, maximum quantum yield

Procedia PDF Downloads 260

Authors: Richard Vuijk, Arnoud Arntz

Abstract:

Rationale: To our knowledge treatment of personality disorder comorbidity in adults with autism spectrum disorder (ASD) is understudied and is still in its infancy: We do not know if treatment of personality disorders may be applicable to adults with ASD. In particular, it is unknown whether patients with ASD benefit from experiential techniques that are part of schema therapy developed for the treatment of personality disorders. Objective: The aim of the study is to investigate the efficacy of a schema mode focused treatment with adult clients with ASD and comorbid personality pathology (i.e. at least one personality disorder). Specifically, we investigate if they can benefit from both cognitive-behavioral, and experiential interventions. Study design: A multiple baseline case series study. Study population: Adult individuals (age > 21 years) with ASD and at least one personality disorder. Participants will be recruited from Sarr expertise center for autism in Rotterdam. The study requires 12 participants. Intervention: The treatment protocol consists of 35 weekly offered sessions, followed by 10 monthly booster sessions. A multiple baseline design will be used with baseline varying from 5 to 10 weeks, with weekly supportive sessions. After baseline, a 5-week exploration phase follows with weekly sessions during which current and past functioning, psychological symptoms, schema modes are explored, and information about the treatment will be given. Then 15 weekly sessions with cognitive-behavioral interventions and 15 weekly sessions with experiential interventions will be given. Finally, there will be a 10-month follow-up phase with monthly booster sessions. Participants are randomly assigned to baseline length, and respond weekly during treatment and monthly at follow-up on Belief Strength of negative core beliefs (by VAS), and fill out SMI, SCL-90 and SRS-A 7 times during screening procedure (i.e. before baseline), after baseline, after exploration, after cognitive and behavioral interventions, after experiential interventions, and after 5- and 10- month follow-up. The SCID-II will be administered during screening procedure (i.e. before baseline), at 5- and at 10-month follow-up. Main study parameters: The primary study parameter is negative core beliefs. Secondary study parameters include schema modes, personality disorder manifestations, psychological symptoms, and social interaction and communication. Discussion: To the best of author’s knowledge so far no study has been published on the application of schema mode focused interventions in adult patients with ASD and comorbid PD(s). This study offers the first systematic test of application of schema therapy for adults with ASD. The results of this study will provide initial evidence for the effectiveness of schema therapy in treating adults with both ASD and PD(s). The study intends to provide valuable information for future development and implementation of therapeutic interventions for adults with both ASD and PD(s).

Keywords: adults, autism spectrum disorder, personality disorder, schema therapy

Procedia PDF Downloads 222

Authors: Mahmood Iqbal, Khalid Nawab, Tachibana Satoshi

Abstract:

Farmer Field School (FFS) is constantly aims to assist farmers to determine and learn about field ecology and integrated crop management. The study was conducted to examine the change in productivity of tomato crop in the study area; to determine increase in per acre yield of the crop, and find out reduction in per acre input cost. A study of tomato crop was conducted in ten villages namely Jabban, Bijligar Colony, Palonow, Heroshah, Zara Maira, Deghar Ghar, Sidra Jour, Anar Thangi, Miangano Korona and Wartair of district Malakand. From each village 15 respondents were selected randomly on the basis of identical allocation making sample size of 150 respondents. The research was based on primary as well as secondary data. Primary data was collected from farmers while secondary data were taken from Agriculture Extension Department Dargai, District Malakand. Interview schedule was planned and each farmer was interviewed personally. The study was based on comparison of cost, yield and income of tomato before and after FFS. Paired t-test and Statistical Package for Social Sciences (SPSS) was used for analysis; outcome of the study show that integrated pest management project has brought a positive change in the attitude of farmers of the project area through FFS approach. In district Malakand 66.0% of the respondents were between the age group of 31-50 years, 11.3% of respondents had primary level of education, 12.7% of middle level, 28.7% metric level, 3.3% of intermediate level and 2.0% of graduate level of education while 42.0% of respondents were illiterate and have no education. Average land holding size of farmers was 6.47 acres, cost of seed, crop protection from insect pest and crop protection from diseases was reduced by Rs. 210.67, Rs. 2584.43 and Rs. 3044.16 respectively, the cost of fertilizers and cost of farm yard manure was increased by Rs.1548.87 and Rs. 1151.40 respectively while tomato yield was increased by 1585.03 kg/acre from 7663.87 to 9248.90 kg/acre. The role of FFS initiate by integrated pest management project through department of agriculture extension for the development of agriculture was worth mentioning. It has brought enhancement in crop yield of tomato and their income through FFS approach. On the basis of results of the research studies, integrated pest management project should spread their developmental activities for maximum participation of the complete rural masses through participatory FFS approach.

Keywords: agriculture, Farmers field schools, extension education, tomato

Procedia PDF Downloads 599

Authors: Mohammed Makha, Jakob Heier, Frank Nüesch, Roland Hany

Abstract:

Organic solar cells (OSCs) have made rapid progress and currently achieve power conversion efficiencies (PCE) of over 10%. OSCs have several merits over other direct light-to-electricity generating cells and can be processed at low cost from solution on flexible substrates over large areas. Moreover, combining organic semiconductors with transparent and conductive electrodes allows for the fabrication of semitransparent OSCs (SM-OSCs). For SM-OSCs the challenge is to achieve a high average visible transmission (AVT) while maintaining a high short circuit current (Jsc). Typically, Jsc of SM-OSCs is smaller than when using an opaque metal top electrode. This is because the non-absorbed light during the first transit through the active layer and the transparent electrode is forward-transmitted out of the device. Recently, OSCs using a ternary blend of organic materials have received attention. This strategy was pursued to extend the light harvesting over the visible range. However, it is a general challenge to manipulate the performance of ternary OSCs in a predictable way, because many key factors affect the charge generation and extraction in ternary solar cells. Consequently, the device performance is affected by the compatibility between the blend components and the resulting film morphology, the energy levels and bandgaps, the concentration of the guest material and its location in the active layer. In this work, we report on a solvent-free lamination process for the fabrication of efficient and semitransparent ternary blend OSCs. The ternary blend was composed of PC70BM and the electron donors PBDTTT-C and an NIR cyanine absorbing dye (Cy7T). Using an opaque metal top electrode, a PCE of 6% was achieved for the optimized binary polymer: fullerene blend (AVT = 56%). However, the PCE dropped to ~2% when decreasing (to 30 nm) the active film thickness to increase the AVT value (75%). Therefore we resorted to the ternary blend and measured for non-transparent cells a PCE of 5.5% when using an active polymer: dye: fullerene (0.7: 0.3: 1.5 wt:wt:wt) film of 95 nm thickness (AVT = 65% when omitting the top electrode). In a second step, the optimized ternary blend was used of the fabrication of SM-OSCs. We used a plastic/metal substrate with a light transmission of over 90% as a transparent electrode that was applied via a lamination process. The interfacial layer between the active layer and the top electrode was optimized in order to improve the charge collection and the contact with the laminated top electrode. We demonstrated a PCE of 3% with AVT of 51%. The parameter space for ternary OSCs is large and it is difficult to find the best concentration ratios by trial and error. A rational approach for device optimization is the construction of a ternary blend phase diagram. We discuss our attempts to construct such a phase diagram for the PBDTTT-C: Cy7T: PC70BM system via a combination of using selective Cy7T selective solvents and atomic force microscopy. From the ternary diagram suitable morphologies for efficient light-to-current conversion can be identified. We compare experimental OSC data with these predictions.

Keywords: organic photovoltaics, ternary phase diagram, ternary organic solar cells, transparent solar cell, lamination

Procedia PDF Downloads 251

Authors: Frea Van Steenweghen, Lander Hollevoet, Johan A. Martens

Abstract:

Compared to other hydrogen (H₂) carriers, ammonia (NH₃) is one of the most promising carriers as it contains 17.6 wt% hydrogen. It is easily liquefied at ≈ 9–10 bar pressure at ambient temperature. More importantly, NH₃ is a carbon-free hydrogen carrier with no CO₂ emission at final decomposition. Ammonia has a well-defined regulatory framework and a good track record regarding safety concerns. Furthermore, the industry already has an existing transport infrastructure consisting of pipelines, tank trucks and shipping technology, as ammonia has been manufactured and distributed around the world for over a century. While NH₃ synthesis and transportation technological solutions are at hand, a missing link in the hydrogen delivery scheme from ammonia is an energy-lean and efficient technology for cracking ammonia into H₂ and N₂. The most explored option for ammonia decomposition is thermo-catalytic cracking which is, by itself, the most energy-efficient approach compared to other technologies, such as plasma and electrolysis, as it is the most energy-lean and robust option. The decomposition reaction is favoured only at high temperatures (> 300°C) and low pressures (1 bar) as the thermocatalytic ammonia cracking process is faced with thermodynamic limitations. At 350°C, the thermodynamic equilibrium at 1 bar pressure limits the conversion to 99%. Gaining additional conversion up to e.g. 99.9% necessitates heating to ca. 530°C. However, reaching thermodynamic equilibrium is infeasible as a sufficient driving force is needed, requiring even higher temperatures. Limiting the conversion below the equilibrium composition is a more economical option. Thermocatalytic ammonia cracking is documented in scientific literature. Among the investigated metal catalysts (Ru, Co, Ni, Fe, …), ruthenium is known to be most active for ammonia decomposition with an onset of cracking activity around 350°C. For establishing > 99% conversion reaction, temperatures close to 600°C are required. Such high temperatures are likely to reduce the round-trip efficiency but also the catalyst lifetime because of the sintering of the supported metal phase. In this research, the first focus was on catalyst bed design, avoiding diffusion limitation. Experiments in our packed bed tubular reactor set-up showed that extragranular diffusion limitations occur at low concentrations of NH₃ when reaching high conversion, a phenomenon often overlooked in experimental work. A second focus was thermocatalyst development for ammonia cracking, avoiding the use of noble metals. To this aim, candidate metals and mixtures were deposited on a range of supports. Sintering resistance at high temperatures and the basicity of the support were found to be crucial catalyst properties. The catalytic activity was promoted by adding alkaline and alkaline earth metals. A third focus was studying the optimum process configuration by process simulations. A trade-off between conversion and favorable operational conditions (i.e. low pressure and high temperature) may lead to different process configurations, each with its own pros and cons. For example, high-pressure cracking would eliminate the need for post-compression but is detrimental for the thermodynamic equilibrium, leading to an optimum in cracking pressure in terms of energy cost.

Keywords: ammonia cracking, catalyst research, kinetics, process simulation, thermodynamic equilibrium

Procedia PDF Downloads 54

Authors: B. T. Naveen Kumar, Anuj Tyagi, Niraj Kumar Singh, Visanu Boonyawiwat, A. H. Shanthanagouda, Orawan Boodde, K. M. Shankar, Prakash Patil, Shubhkaramjeet Kaur

Abstract:

Early mortality syndrome (EMS)/Acute Hepatopancreatic Necrosis Disease (AHPND) has emerged as a major obstacle for the shrimp farming around the world. It is caused by a strain of Vibrio parahaemolyticus. The possible preventive and control measure is, early and rapid detection of the pathogen in the broodstock, post-larvae and monitoring the shrimp during the culture period. Polymerase chain reaction (PCR) based early detection methods are good, but they are costly, time taking and requires a sophisticated laboratory. The present study was conducted to develop a simple, sensitive and rapid diagnostic farmer level kit for the reliable detection of AHPND in shrimp. A panel of monoclonal antibodies (MAbs) were raised against the recombinant Pir B protein (rPirB). First, an immunodot was developed by using MAbs G3B8 and Mab G3H2 which showed specific reactivity to purified r-PirB protein with no cross-reactivity to other shrimp bacterial pathogens (AHPND free Vibrio parahaemolyticus (Indian strains), V. anguillarum, WSSV, Aeromonas hydrophila, and Aphanomyces invadans). Immunodot developed using Mab G3B8 is more sensitive than that with the Mab G3H2. However, immunodot takes almost 2.5 hours to complete with several hands-on steps. Therefore, the flow-through assay (FTA) was developed by using a plastic cassette containing the nitrocellulose membrane with absorbing pads below. The sample was dotted in the test zone on the nitrocellulose membrane followed by continuos addition of five solutions in the order of i) blocking buffer (BSA) ii) primary antibody (MAb) iii) washing Solution iv) secondary antibody and v) chromogen substrate (TMB) clear purple dots against a white background were considered as positive reactions. The FTA developed using MAbG3B8 is more sensitive than that with MAb G3H2. In FTA the two MAbs showed specific reactivity to purified r-PirB protein and not to other shrimp bacterial pathogens. The FTA is simple to farmer/field level, sensitive and rapid requiring only 8-10 min for completion. Tests can be developed to kits, which will be ideal for use in biosecurity, for the first line of screening (at the port or pond site) and during monitoring and surveillance programmes overall for the good management practices to reduce the risk of the disease.

Keywords: acute hepatopancreatic necrosis disease, AHPND, flow-through assay, FTA, farmer level, immunodot, pond site, shrimp

Procedia PDF Downloads 162

Authors: Dylan Santos De Pinho, Nabil Ouerhani

Abstract:

Energy consumption of machine-tools is becoming critical for machine-tool builders and end-users because of economic, ecological and legislation-related reasons. Many machine-tool builders are seeking for solutions that allow the reduction of energy consumption of machine-tools while preserving the same productivity rate and the same quality of machined parts. In this paper, we present the first results of a project conducted jointly by academic and industrial partners to reduce the energy consumption of a Swiss-Type lathe. We employ genetic algorithms to find optimal machining parameters – the set of parameters that lead to the best trade-off between energy consumption, part quality and tool lifetime. Three main machining process parameters are considered in our optimization technique, namely depth of cut, spindle rotation speed and material feed rate. These machining process parameters have been identified as the most influential ones in the configuration of the Swiss-type machining process. A state-of-the-art multi-objective genetic algorithm has been used. The algorithm combines three fitness functions, which are objective functions that permit to evaluate a set of parameters against the three objectives: energy consumption, quality of the machined parts, and tool lifetime. In this paper, we focus on the investigation of the fitness function related to energy consumption. Four different energy consumption related fitness functions have been investigated and compared. The first fitness function refers to the Kienzle cutting force model. The second fitness function uses the Material Removal Rate (RMM) as an indicator of energy consumption. The two other fitness functions are non-deterministic, learning-based functions. One fitness function uses a simple Neural Network to learn the relation between the process parameters and the energy consumption from experimental data. Another fitness function uses Lasso regression to determine the same relation. The goal is, then, to find out which fitness functions predict best the energy consumption of a Swiss-Type machining process for the given set of machining process parameters. Once determined, these functions may be used for optimization purposes – determine the optimal machining process parameters leading to minimum energy consumption. The performance of the four fitness functions has been evaluated. The Tornos DT13 Swiss-Type Lathe has been used to carry out the experiments. A mechanical part including various Swiss-Type machining operations has been selected for the experiments. The evaluation process starts with generating a set of CNC (Computer Numerical Control) programs for machining the part at hand. Each CNC program considers a different set of machining process parameters. During the machining process, the power consumption of the spindle is measured. All collected data are assigned to the appropriate CNC program and thus to the set of machining process parameters. The evaluation approach consists in calculating the correlation between the normalized measured power consumption and the normalized power consumption prediction for each of the four fitness functions. The evaluation shows that the Lasso and Neural Network fitness functions have the highest correlation coefficient with 97%. The fitness function “Material Removal Rate” (MRR) has a correlation coefficient of 90%, whereas the Kienzle-based fitness function has a correlation coefficient of 80%.

Keywords: adaptive machining, genetic algorithms, smart manufacturing, parameters optimization

Procedia PDF Downloads 137

Authors: Laura Southgate

Abstract:

The Association of Southeast Asian Nations (ASEAN), as well as much of the scholarship on the organisation, celebrates its ability to uphold the principle of regional autonomy, understood as upholding the norm of non-intervention by external powers in regional affairs. Yet, in practice, this has been repeatedly violated. This dichotomy between rhetoric and practice suggests an interesting avenue for further study. The East Timor crisis (1975-1999) has been selected as a case-study to test the dynamics of ASEAN state resistance to sovereignty violation in two distinct timeframes: Indonesia’s initial invasion of the territory in 1975, and the ensuing humanitarian crisis in 1999 which resulted in a UN-mandated, Australian-led peacekeeping intervention force. These time-periods demonstrate variation on the dependent variable. It is necessary to observe covariation in order to derive observations in support of a causal theory. To establish covariation, my independent variable is therefore a continuous variable characterised by variation in convergence of interest. Change of this variable should change the value of the dependent variable, thus establishing causal direction. This paper investigates the history of ASEAN’s relationship to the norm of non-intervention. It offers an alternative understanding of ASEAN’s history, written in terms of the relationship between a key ASEAN state, which I call a ‘vanguard state’, and selected external powers. This paper will consider when ASEAN resistance to sovereignty violation has succeeded, and when it has failed. It will contend that variation in outcomes associated with vanguard state resistance to sovereignty violation can be best explained by levels of interest convergence between the ASEAN vanguard state and designated external actors. Evidence will be provided to support the hypothesis that in 1999, ASEAN’s failure to resist violations to the sovereignty of Indonesia was a consequence of low interest convergence between Indonesia and the external powers. Conversely, in 1975, ASEAN’s ability to resist violations to the sovereignty of Indonesia was a consequence of high interest convergence between Indonesia and the external powers. As the vanguard state, Indonesia was able to apply pressure on the ASEAN states and obtain unanimous support for Indonesia’s East Timor policy in 1975 and 1999. However, the key factor explaining the variance in outcomes in both time periods resides in the critical role played by external actors. This view represents a serious challenge to much of the existing scholarship that emphasises ASEAN’s ability to defend regional autonomy. As these cases attempt to show, ASEAN autonomy is much more contingent than portrayed in the existing literature.

Keywords: ASEAN, east timor, intervention, sovereignty

Procedia PDF Downloads 343

Authors: Aliya K. Salahova

Abstract:

Scientific thinking, characterized by purposeful knowledge-seeking and the harmonization of theory and facts, holds a crucial role in preparing young minds for an increasingly complex and technologically advanced world. This abstract presents a research study aimed at fostering scientific thinking in early childhood, focusing on children aged 5 to 9 years, through experiential learning in Kids Science Labs (STEM). The study utilized a longitudinal exploration design, spanning 240 weeks from September 2018 to April 2023, to evaluate the effectiveness of the Kids Science Labs program in developing scientific thinking skills. Participants in the research comprised 72 children drawn from local schools and community organizations. Through a formative psychology-pedagogical experiment, the experimental group engaged in weekly STEM activities carefully designed to stimulate scientific thinking, while the control group participated in daily art classes for comparison. To assess the scientific thinking abilities of the participants, a registration table with evaluation criteria was developed. This table included indicators such as depth of questioning, resource utilization in research, logical reasoning in hypotheses, procedural accuracy in experiments, and reflection on research processes. The data analysis revealed dynamic fluctuations in the number of children at different levels of scientific thinking proficiency. While the development was not uniform across all participants, a main leading factor emerged, indicating that the Kids Science Labs program and formative experiment exerted a positive impact on enhancing scientific thinking skills in children within this age range. The study's findings support the hypothesis that systematic implementation of STEM activities effectively promotes and nurtures scientific thinking in children aged 5-9 years. Enriching education with a specially planned STEM program, tailoring scientific activities to children's psychological development, and implementing well-planned diagnostic and corrective measures emerged as essential pedagogical conditions for enhancing scientific thinking abilities in this age group. The results highlight the significant and positive impact of the systematic-activity approach in developing scientific thinking, leading to notable progress and growth in children's scientific thinking abilities over time. These findings have promising implications for educators and researchers, emphasizing the importance of incorporating STEM activities into educational curricula to foster scientific thinking from an early age. This study contributes valuable insights to the field of science education and underscores the potential of STEM-based interventions in shaping the future scientific minds of young children.

Keywords: Scientific thinking, education, STEM, intervention, Psychology, Pedagogy, collaborative learning, longitudinal study

Procedia PDF Downloads 51

Authors: Farzan Gity, Lida Ansari, Ian M. Povey, Roger E. Nagle, James C. Greer

Abstract:

Titanium nitride (TiN) films have been widely used in variety of fields, due to its unique electrical, chemical, physical and mechanical properties, including low electrical resistivity, chemical stability, and high thermal conductivity. In microelectronic devices, thin continuous TiN films are commonly used as diffusion barrier and metal gate material. However, as the film thickness decreases below a few nanometers, electrical properties of the film alter considerably. In this study, the physical and electrical characteristics of 1.5nm to 22nm thin films deposited by Plasma-Enhanced Atomic Layer Deposition (PE-ALD) using Tetrakis(dimethylamino)titanium(IV), (TDMAT) chemistry and Ar/N2 plasma on 80nm SiO2 capped in-situ by 2nm Al2O3 are investigated. ALD technique allows uniformly-thick films at monolayer level in a highly controlled manner. The chemistry incorporates low level of oxygen into the TiN films forming titanium oxynitride (TiON). Thickness of the films is characterized by Transmission Electron Microscopy (TEM) which confirms the uniformity of the films. Surface morphology of the films is investigated by Atomic Force Microscopy (AFM) indicating sub-nanometer surface roughness. Hall measurements are performed to determine the parameters such as carrier mobility, type and concentration, as well as resistivity. The >5nm-thick films exhibit metallic behavior; however, we have observed that thin film resistivity is modulated significantly by film thickness such that there are more than 5 orders of magnitude increment in the sheet resistance at room temperature when comparing 5nm and 1.5nm films. Scattering effects at interfaces and grain boundaries could play a role in thickness-dependent resistivity in addition to quantum confinement effect that could occur at ultra-thin films: based on our measurements the carrier concentration is decreased from 1.5E22 1/cm3 to 5.5E17 1/cm3, while the mobility is increased from < 0.1 cm2/V.s to ~4 cm2/V.s for the 5nm and 1.5nm films, respectively. Also, measurements at different temperatures indicate that the resistivity is relatively constant for the 5nm film, while for the 1.5nm film more than 2 orders of magnitude reduction has been observed over the range of 220K to 400K. The activation energy of the 2.5nm and 1.5nm films is 30meV and 125meV, respectively, indicating that the TiON ultra-thin films are exhibiting semiconducting behaviour attributing this effect to a metal-semiconductor transition. By the same token, the contact is no longer Ohmic for the thinnest film (i.e., 1.5nm-thick film); hence, a modified lift-off process was developed to selectively deposit thicker films allowing us to perform electrical measurements with low contact resistance on the raised contact regions. Our atomic scale simulations based on molecular dynamic-generated amorphous TiON structures with low oxygen content confirm our experimental observations indicating highly n-type thin films.

Keywords: activation energy, ALD, metal-semiconductor transition, resistivity, titanium oxynitride, ultra-thin film

Procedia PDF Downloads 280