Search results for: mechanical responses

Authors: Kaaryn Cater

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People vary in how they perceive, process, and react to internal, external, social, and emotional environmental factors; some are more sensitive than others. Compassionate people have a highly reactive nervous system and are more impacted by positive and negative environmental conditions (Differential Susceptibility). Further, some sensitive individuals are disproportionately able to benefit from positive and supportive environments without necessarily suffering negative impacts in less supportive environments (Vantage Sensitivity). Environmental sensitivity is underpinned by physiological, genetic, and personality/temperamental factors, and the phenotypic expression of high sensitivity is Sensory Processing Sensitivity. The hallmarks of Sensory Processing Sensitivity are deep cognitive processing, emotional reactivity, high levels of empathy, noticing environmental subtleties, a tendency to observe new and novel situations, and a propensity to become overwhelmed when over-stimulated. Several educational advantages associated with high sensitivity include creativity, enhanced memory, divergent thinking, giftedness, and metacognitive monitoring. High sensitivity can also lead to some educational challenges, particularly managing multiple conflicting demands and negotiating low sensory thresholds. A mixed methods study was undertaken. In the first quantitative study, participants completed the Perceived Success in Study Survey (PSISS) and the Highly Sensitive Person Scale (HSPS-12). Inclusion criteria were current or previous postsecondary education experience. The survey was presented on social media, and snowball recruitment was employed (n=365). The Excel spreadsheets were uploaded to the statistical package for the social sciences (SPSS)26, and descriptive statistics found normal distribution. T-tests and analysis of variance (ANOVA) calculations found no difference in the responses of demographic groups, and Principal Components Analysis and the posthoc Tukey calculations identified positive associations between high sensitivity and three of the five PSISS factors. Further ANOVA calculations found positive associations between the PSISS and two of the three sensitivity subscales. This study included a response field to register interest in further research. Respondents who scored in the 70th percentile on the HSPS-12 were invited to participate in a semi-structured interview. Thirteen interviews were conducted remotely (12 female). Reflexive inductive thematic analysis was employed to analyse data, and a descriptive approach was employed to present data reflective of participant experience. The results of this study found that compassionate students prioritize work-life balance; employ a range of practical metacognitive study and self-care strategies; value independent learning; connect with learning that is meaningful; and are bothered by aspects of the physical learning environment, including lighting, noise, and indoor environmental pollutants. There is a dearth of research investigating sensitivity in the educational context, and these studies highlight the need to promote widespread education sector awareness of environmental sensitivity, and the need to include sensitivity in sector and institutional diversity and inclusion initiatives.

Keywords: differential susceptibility, highly sensitive person, learning, neurosensitivity, sensory processing sensitivity, vantage sensitivity

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Authors: Salise Oktay, Nilgun Kizilcan, Basak Bengu

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At present, formaldehyde-based adhesives such as urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine – urea-formaldehyde (MUF), etc. are mostly used in wood-based panel industry because of their high reactivity, chemical versatility, and economic competitiveness. However, formaldehyde-based wood adhesives are produced from non- renewable resources and also formaldehyde is classified as a probable human carcinogen (Group B1) by the U.S. Environmental Protection Agency (EPA). Therefore, there has been a growing interest in the development of environment-friendly, economically competitive, bio-based wood adhesives to meet wood-based panel industry requirements. In this study, like a formaldehyde-free adhesive, oxidized starch – urea wood adhesives was synthesized. In this scope, firstly, acid hydrolysis of corn starch was conducted and then acid thinned corn starch was oxidized by using hydrogen peroxide and CuSO₄ as an oxidizer and catalyst, respectively. Secondly, the polycondensation reaction between oxidized starch and urea conducted. Finally, nano – TiO₂ was added to the reaction system to strengthen the adhesive network. Solid content, viscosity, and gel time analyses of the prepared adhesive were performed to evaluate the adhesive processability. FTIR, DSC, TGA, SEM characterization techniques were used to investigate chemical structures, thermal, and morphological properties of the adhesive, respectively. Rheological analysis of the adhesive was also performed. In order to evaluate the quality of oxidized corn starch – urea adhesives, particleboards were produced in laboratory scale and mechanical and physical properties of the boards were investigated such as an internal bond, modulus of rupture, modulus of elasticity, formaldehyde emission, etc. The obtained results revealed that oxidized starch – urea adhesives were synthesized successfully and it can be a good potential candidate to use the wood-based panel industry with some developments.

Keywords: nano-TiO₂, corn starch, formaldehyde emission, wood adhesives

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Authors: Afshin Zohdi, Selçuk Özdemir, Mustafa Aksoy

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Tungsten carbide-cobalt (WC-Co) is a widely utilized material for cold forming dies, including those employed in fastener production. In this study, we investigated the effectiveness of the pack boriding method in improving the surface properties of WC-Co cold forging dies. The boriding process involved embedding WC-Co samples, along with a steel control sample, within a chamber made of H13 tool steel. A boriding powder mixture was introduced into the chamber, which was then sealed using a paste. Subsequently, the samples were subjected to a temperature of 700°C for 5 hours in a furnace. Microstructural analysis, including cross-sectional examination and scanning electron microscopy (SEM), confirmed successful boron diffusion and its presence on the surface of the borided samples. The microhardness of the borided layer was significantly increased (3980 HV1) compared to the unborided sample (1320 HV3), indicating enhanced hardness. The borided layer exhibited an acceptable thickness of 45 microns, with a diffusion coefficient of 1.125 × 10-7 mm²/s, signifying a moderate diffusion rate. Energy-dispersive X-ray spectroscopy (EDS) mapping revealed an increase in boron content, desirable for the intended purpose, while an undesired increase in oxygen content was observed. Furthermore, the pin-on-disk wear test demonstrated a reduction in friction coefficient, indicating improved mechanical and tribological properties of the surface. The successful implementation of the pack boriding process highlights its potential for enhancing the performance of WC-Co cold forging dies.

Keywords: WC-Co, cold forging dies, pack boriding, surface hardness, wear resistance, microhardness, diffusion coefficient, scanning electron microscopy, energy-dispersive X-ray spectroscopy

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Authors: Maryline Vere, Wilma ten Ham-Baloyi, Lucy Ochola, Opeoluwa Oyedele, Lindsey Beyleveld, Siphokazi Tili, Takafira Mduluza, Paula E. Melariri

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Schistosomiasis, caused by Schistosoma (S.) haematobium and Schistosoma (S.) mansoni parasites poses a significant public health challenge in low-income regions. Diagnosis typically relies on identifying specific urine biomarkers such as haematuria, protein, and leukocytes for S. haematobium, while the Point-of-Care Circulating Cathodic Antigen (POC-CCA) assay is employed for detecting S. mansoni. Urinalysis and the POC-CCA assay are favoured for their rapid, non-invasive nature and cost-effectiveness. However, traditional diagnostic methods such as Kato-Katz and urine filtration lack sensitivity in low-transmission areas, which can lead to underreporting of cases and hinder effective disease control efforts. Therefore, in this study, urinalysis and the POC-CCA assay was utilised to diagnose schistosomiasis effectively among school-going children in Nelson Mandela Bay Municipality. This was a cross-sectional study with a total of 759 children, aged 5 to 14 years, who provided urine samples. Urinalysis was performed using urinary dipstick tests, which measure multiple parameters, including haematuria, protein, leukocytes, bilirubin, urobilinogen, ketones, pH, specific gravity and other biomarkers. Urinalysis was performed by dipping the strip into the urine sample and observing colour changes on specific reagent pads. The POC-CCA test was conducted by applying a drop of urine onto a cassette containing CCA-specific antibodies, and the presence of a visible test line indicated a positive result for S. mansoni infection. Descriptive statistics were used to summarize urine parameters, and Pearson correlation coefficients (r) were calculated to analyze associations among urine parameters using R software (version 4.3.1). Among the 759 children, the prevalence of S. haematobium using haematuria as a diagnostic marker was 33.6%. Additionally, leukocytes were detected in 21.3% of the samples, and protein was present in 15%. The prevalence of positive POC-CCA test results for S. mansoni was 3.7%. Urine parameters exhibited low to moderate associations, suggesting complex interrelationships. For instance, specific gravity and pH showed a negative correlation (r = -0.37), indicating that higher specific gravity was associated with lower pH. Weak correlations were observed between haematuria and pH (r = -0.10), bilirubin and ketones (r = 0.14), protein and bilirubin (r = 0.13), and urobilinogen and pH (r = 0.12). A mild positive correlation was found between leukocytes and blood (r = 0.23), reflecting some association between these inflammation markers. In conclusion, the study identified a significant prevalence of schistosomiasis among school-going children in Nelson Mandela Bay Municipality, with S. haematobium detected through haematuria and S. mansoni identified using the POC-CCA assay. The detection of leukocytes and protein in urine samples serves as critical biomarkers for schistosomiasis infections, reinforcing the presence of schistosomiasis in the study area when considered alongside haematuria. These urine parameters are indicative of inflammatory responses associated with schistosomiasis, underscoring the necessity for effective diagnostic methodologies. Such findings highlight the importance of comprehensive diagnostic assessments to accurately identify and monitor schistosomiasis prevalence and its associated health impacts. The significant burden of schistosomiasis in this population highlights the urgent need to develop targeted control interventions to effectively reduce its prevalence in the study area.

Keywords: schistosomiasis, urinalysis, haematuria, POC-CCA

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Authors: Amna Tariq Shah

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Amid the pandemic, the contemporary landscape has experienced accelerated growth in small business activities and an expanding digital marketplace, further exacerbating the issue of non-compliance among self-employed individuals through aggressive tax planning and evasion. This research seeks to address these challenges by developing strategic tax policies that promote voluntary compliance and improve taxpayer facilitation. The study employs the innovative MINDSPACE framework to examine three psychosocial factors—tax communication, tax literacy, and shaming—to optimize policy responses, address administrative shortcomings, and ensure adequate revenue collection for public goods and services. Preliminary findings suggest that incomprehensible communication from tax authorities drives individuals to seek alternative, potentially biased sources of tax information, thereby exacerbating non-compliance. Furthermore, the study reveals low tax literacy among Australian and Pakistani respondents, with many struggling to navigate complex tax processes and comprehend tax laws. Consequently, policy recommendations include simplifying tax return filing and enhancing pre-populated tax returns. In terms of shaming, the research indicates that Australians, being an individualistic society, may not respond well to shaming techniques due to privacy concerns. In contrast, Pakistanis, as a collectivistic society, may be more receptive to naming and shaming approaches. The study employs a mixed-method approach, utilizing interviews and surveys to analyze the issue in both jurisdictions. The use of mixed methods allows for a more comprehensive understanding of tax compliance behavior, combining the depth of qualitative insights with the generalizability of quantitative data, ultimately leading to more robust and well-informed policy recommendations. By examining evidence from opposite jurisdictions, namely a developed country (Australia) and a developing country (Pakistan), the study's applicability is enhanced, providing perspectives from two disparate contexts that offer insights from opposite ends of the economic, cultural, and social spectra. The non-comparative case study methodology offers valuable insights into human behavior, which can be applied to other jurisdictions as well. The application of the MINDSPACE framework in this research is particularly significant, as it introduces a novel approach to tax compliance behavior analysis. By integrating insights from behavioral economics, the framework enables a comprehensive understanding of the psychological and social factors influencing taxpayer decision-making, facilitating the development of targeted and effective policy interventions. This research carries substantial importance as it addresses critical challenges in tax compliance and administration, with far-reaching implications for revenue collection and the provision of public goods and services. By investigating the psychosocial factors that influence taxpayer behavior and utilizing the MINDSPACE framework, the study contributes invaluable insights to the field of tax policy. These insights can inform policymakers and tax administrators in developing more effective tax policies that enhance taxpayer facilitation, address administrative obstacles, promote a more equitable and efficient tax system, and foster voluntary compliance, ultimately strengthening the financial foundation of governments and communities.

Keywords: individual tax compliance behavior, psychosocial factors, tax non-compliance, tax policy

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Authors: Natasa Ilic, Alisa Gruden-Movsesijan, Maja Kosanovic, Sofija Glamoclija, Marina Bekic, Ljiljana Sofronic-Milosavljevic, Sergej Tomic

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As a very promising candidate for modulation of immune response in the sense of biasing the inflammatory towards an anti-inflammatory type of response, Trichinella spiralis infection was shown to successfully alleviate the severity of experimental autoimmune encephalomyelitis, the animal model of human disease multiple sclerosis. This effect is achieved via its excretory-secretory muscle larvae (ES L1) products which affect the maturation status and function of dendritic cells (DCs) by inducing the tolerogenic status of DCs, which leads to the mitigation of the Th1 type of response and the activation of a regulatory type of immune response both in vitro and in vivo. ES L1 alone or via treated DCs successfully mitigated EAE in the same manner as the infection itself. On the other hand, it has been shown that T. spiralis infection slows down the tumour growth and significantly reduces the tumour size in the model of mouse melanoma, while ES L1 possesses a pro-apoptotic and anti-survival effect on melanoma cells in vitro. Hence, although the mechanisms still need to be revealed, T. spiralis infection and its ES L1 products have a bit of controversial potential to modulate both inflammatory diseases and malignancies. The recent discovery of T. spiralis extracellular vesicles (TsEVs) suggested that the induction of complex regulation of the immune response requires simultaneous delivery of different signals in nano-sized packages. This study aimed to explore whether TsEVs bare the similar potential as ES L1 to influence the status of DCs in initiation, progression and regulation of immune response, but also to investigate the effect of both ES L1 and TsEVs on myeloid derived suppressor cells (MDSC) which present the regular tumour tissue environment. TsEVs were enriched from the conditioned medium of T. spiralis muscle larvae by differential centrifugation and used for the treatment of human monocyte-derived DCs and MDSC. On DCs, TsEVs induced low expression of HLA DR and CD40, moderate CD83 and CD86, and increased expression of ILT3 and CCR7 on treated DCs, i.e., they induced tolerogenic DCs. Such DCs possess the capacity to polarize T cell immune response towards regulatory type, with an increased proportion of IL-10 and TGF-β producing cells, similarly to ES L1. These findings indicated that the ability of TsEVs to induce tolerogenic DCs favoring anti-inflammatory responses may be helpful in coping with diseases that involve Th1/Th17-, but also Th2-mediated inflammation. In MDSC in vitro model, although both ES L1 and TsEVs had the same impact on MDSC phenotype i.e., they acted suppressive, ES L1 treated MDSC, unlike TsEVs treated ones, induced T cell response characterized by the increased RoRγT and IFN-γ, while the proportion of regulatory cells was decreased followed by the decrease in IL-10 and TGF-β positive cells proportion within this population. These findings indicate the interesting ability of ES L1 to modulate T cells response via MDSC towards pro-inflamatory type, suggesting that, unlike TsEVs which consistently demonstrate the suppresive effect on inflammatory response, it could be used also for the development of new approaches aimed for the treatment of malignant diseases. Acknowledgment: This work was funded by the Promis project – Nano-MDCS-Thera, Science Fund, Republic of Serbia.

Keywords: dendritic cells, myeloid derived suppressor cells, immunomodulation, Trichinella spiralis

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Authors: Brooklyn Rushton, Michelle Rutty, Natalie Knowles, Daniel Scott

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As people are increasingly on the search for extraordinary experiences and connections with nature, adventure tourism is experiencing significant growth and providing tourists with life-changing experiences. Unlike built attraction-based tourism, adventure tourism relies entirely on natural heritage, which leaves communities dependent on adventure tourism extremely vulnerable to environmental and climatic changes. A growing body of evidence suggests that global climate change will influence the future of adventure tourism and mountain outdoor recreation opportunities on a global scale. Across Canada, more specifically, climate change is broadly anticipated to present risks for winter-snow sports, while opportunities are anticipated to arise for green season activities. These broad seasonal shifts do not account for the indirect impacts of climate change on adventure tourism, such as the cost of adaptation or the increase of natural hazards and the associated likelihood of accidents. While some research has examined the impact of climate change on natural environments that adventure tourism relies on, a very small body of research has specifically focused on guides’ perspectives or included hard adventure tourism activities. The guiding industry is unique, as guides are trained through an elegant blend of art and science to make decisions based on experience, observation, and intuition. While quantitative research can monitor change in natural environments, guides local knowledge can provide eye-witness accounts and outline what environmental changes mean for the future sustainability of adventure tourism. This research will capture the extensive knowledge of mountain guides to better understand the implications of climate change for mountain adventure and potential adaptive responses for the adventure tourism industry. This study uses a structured online survey with open and close-ended questions that will be administered using Qualtrics (an online survey platform). This survey is disseminated to current members of the Association of Canadian Mountain Guides (ACMG). Participation in this study will be exclusive to members of the ACMG operating in the outdoor guiding streams. The 25 survey questions are organized into four sections: demographic and professional operation (9 questions), physical change (4 questions), climate change perception (6 questions), and climate change adaptation (6 questions). How mountain guides perceive and respond to climate change is important knowledge for the future of the expanding adventure tourism industry. Results from this study are expected to provide important information to mountain destinations on climate change vulnerability and adaptive capacity. Expected results of this study include guides insight into: (1) experience-safety relevant observed physical changes in guided regions (i.e. glacial coverage, permafrost coverage, precipitation, temperature, and slope instability) (2) changes in hazards within the guiding environment (i.e. avalanches, rockfall, icefall, forest fires, flooding, and extreme weather events), (3) existing and potential adaptation strategies, and (4) key information and other barriers for adaptation. By gaining insight from the knowledge of mountain guides, this research can help the tourism industry at large understand climate risk and create adaptation strategies to ensure the resiliency of the adventure tourism industry.

Keywords: adventure tourism, climate change, environmental change, mountain hazards

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Authors: Biswajit Pal, Amit Mallik, Anil K. Barik

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Current years have witnessed a phenomenal growth in the research on the rare earth-doped transparent host materials, the essential components in optoelectronics that meet up the increasing demand for fabrication of high quality optical devices especially in telecommunication system. The combination of low phonon energy (because of fluoride environment) and high chemical durability with superior mechanical stability (due to oxide environment) makes the oxyfluoride glass–ceramics the promising and useful materials in optoelectronics. The present work reports on the undoped and doped (1 mol% Pr2O3) glass ceramics of composition 16.52 Al2O3•1.5AlF3• 12.65LaF3•4.33Na2O•64.85 SiO2 (mol%), prepared by melting technique initially that follows annealation at 450 ºC for 1 h. The glass samples so obtained were heat treated at constant 600 ºC with a variation in heat treatment schedule (10- 80 h). TEM techniques were employed to structurally characterize the glass samples. Pr2O3 affects the phase separation in the glass and delays the onset of crystallization in the glass ceramic. The modified crystallization mechanism is established from the analysis of advanced STEM/EDXS results. The phase separated droplets after annealing turn into 10-20 nm of LaF3 nano crystals those upon scrutiny are found to be dotted with the doped Pr3+ ions within the crystals themselves. The EDXS results also suggest that the inner LaF3 crystal core is swallowed by an Al enriched layer that follows a Si enriched surrounding shell as the outer core. This greatly increases the viscosity in the periphery of the crystals that restricts further crystal growth to account for the formation of nano sized crystals.

Keywords: advanced STEM/EDXS, crystallization mechanism, nano crystals, pr3+ ion doped glass and glass ceramic, structural characterization

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Authors: Souhir Abid

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The growing interest in vegetal biomass as an alternative for fossil resources has stimulated the development of numerous classes of monomers. Polymers from renewable resources have attracted an increasing amount of attention over the last two decades, predominantly due to two major reasons (i) firstly environmental concerns, and (ii) secondly the use of monomers from renewable feedstock is a steadily growing field of interest in order to reduce the amount of petroleum consumed in the chemical industry and to open new high-value-added markets to agriculture. Furanic polymers have been considered as alternative environmentally friendly polymers. In our earlier work, modifying furanic polyesters by incorporation of amide functions along their backbone, lead to a particular class of polymer ‘poly(ester-amide)s’, was investigated to combine the excellent mechanical properties of polyamides and the biodegradability of polyesters. As a continuation of our studies on this family of polymer, a series of furanic poly(ester-amide)s bearing sulfonate groups in the main chain were synthesized from 5,5’-Isopropylidene-bis(ethyl 2-furoate), dimethyl 5-sodiosulfoisophthalate, ethylene glycol and hexamethylene diamine by melt polycondensation using zinc acetate as a catalyst. In view of the complexity of the NMR spectrum analysis of the resulting sulfonated poly(ester-amide)s, we found that it is useful to prepare initially the corresponding homopolymers: sulfonated polyesters and polyamides. Structural data of these polymers will be used as a basic element in 1H NMR characterization. The hydrolytic degradation in acidic aqueous conditions (pH = 4,35 ) at 37 °C over the period of four weeks show that the mechanism of the hydrolysis of poly(ester amide)s was elucidated in relation with the microstructure. The strong intermolecular hydrogen bonding interactions between amide functions and water molecules increases the hydrophilicity of the macromolecular chains and consequently their hydrolytic degradation.

Keywords: furan, hydrolytic degradation, polycondensation, poly(ester amide)

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Authors: Bernice Lottering, Yi-Wen Lin

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Chronic pain and depression have an estimated 80% rate of comorbidity with unsatisfactory treatment interventions signifying the importance of developing effective therapeutic interventions for a serious chronic condition affecting a large majority of the global population. Chronic pain is defined as persistent pain presenting for over 3 months. This disease state increases the risk of developing depression in comparison to healthy individuals. In the current study, complete Freund’s adjuvant (CFA) was used to induce cell-mediated chronic inflammatory pain in a murine model. Significant mechanical and thermal hyperalgesia was induced, alongside observable depression-like behaviors. These conditions were attenuated through the use of electroacupuncture (EA). Similarly, these effects were also investigated with respect to the transient receptor potential vanilloid 1 (TRPV1), by analyzing the effects of TRPV1 gene deletion on the comorbidity of chronic pain and depression. The expression of the TRPV1 inflammatory response, and related downstream molecules, including protein kinases (PKs), mitogen-activated protein kinase (MAPKs), and transcriptional factors, were significantly reduced in the thalamus, prefrontal cortex (PFC), hippocampus, and periaqueductal gray (PAG) of CFA-treated mice. In addition, phosphorylated N-methyl-D-aspartate (NMDA) receptor 1 was also found to be reduced in the aforementioned areas, suggesting potential application and validity in a clinical setting. Our study determined the prospective therapeutic effects of EA in the treatment of chronic inflammatory pain and depression comorbidity and provides a novel and detailed mechanism underlying EA-mediated analgesia. These findings may be relevant in the utilization of clinical intervention approaches related to chronic pain and depression comorbidity.

Keywords: chronic pain, depression, NMDA, prefrontal cortex, TRPV1

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Authors: Maria Bercea, Monica Diana Olteanu

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Investigation of polymer systems able to change inside of the body into networks represent an attractive approach, especially when there is a minimally invasive and patient friendly administration. Pharmaceutical formulations based on Pluronic F127 [poly (oxyethylene) (PEO) blocks (70%) and poly(oxypropylene) (PPO) blocks (30%)] present an excellent potential as drug delivery systems. The use of Pluronic F127 alone as gel-forming solution is limited by some characteristics, such as poor mechanical properties, short residence time, high permeability, etc. Investigation of the interactions between the natural and synthetic polymers and surfactants in solution is a subject of great interest from both scientific and practical point of view. As for example, formulations based on Pluronics and chitosan could be used to obtain dual phase transition hydrogels responsive to temperature and pH changes. In this study, different materials were prepared by using poly(vinyl alcohol), chitosan solutions mixed with aqueous solutions of Pluronic F127. The rheological properties of different formulations were investigated in temperature sweep experiments as well as at a constant temperature of 37oC for exploring in-situ gel formation in the human body conditions. In addition, some viscometric investigations were carried out in order to understand the interactions which determine the complex behaviour of these systems. Correlation between the thermodynamic and rheological parameters and phase separation phenomena observed for the investigated systems allowed the dissemination the constitutive response of polymeric materials at different external stimuli, such as temperature and pH. The rheological investigation demonstrated that the viscoelastic moduli of the hydrogels can be tuned depending on concentration of different components as well as pH and temperature conditions and cumulative contributions can be obtained.

Keywords: hydrogel, polymer mixture, stimuli responsive, biomedical applications

Procedia PDF Downloads 350

Authors: Akram Boubakri, Fethi Choubani, Tan Hoa Vuong, Jacques David

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Nowadays, microwave hyperthermia is considered as an effective treatment for the malignant tumors. This microwave treatment which comes to substitute the chemotherapy and the surgical intervention enables an in-depth tumor heating without causing any diseases to the sane tissue. This technique requires a high precision system, in order to effectively concentrate the heating just in the tumor, without heating any surrounding healthy tissue. In the hyperthermia treatment, the temperature in cancerous area is typically raised up to over 42◦C and maintained for one hour in order to destroy the tumor sufficiently, whilst in the surrounding healthy tissues, the temperature is maintained below 42◦C to avoid any damage. Metamaterial lenses are widely used in medical applications like microwave hyperthermia treatment. They enabled a subdiffraction resolution thanks to the amplification of the evanescent waves and they can focus electromagnetic waves from a point source to a point image. Metasurfaces have been used to built metamaterial lenses. The main mechanical advantages of those structures over three dimensional material structures are ease of fabrication and a smaller required volume. Here in this work, we proposed a metasurface based lens operating at the frequency of 6 GHz and designed for microwave hyperthermia. This lens was applied and showed good results in focusing and heating the tumor inside a breast tissue with an increased and maintained temperature above 42°C. The tumor was placed in the focal distance of the lens so that only the tumor tissue will be heated. Finally, in this work, it has been shown that the hyperthermia area within the tissue can be carefully adjusted by moving the antennas or by changing the thickness of the metamaterial lenses based on the tumor position. Even though the simulations performed in this work have taken into account an ideal case, some real characteristics can be considered to improve the obtained results in a realistic model.

Keywords: focusing, hyperthermia, metamaterial lenses, metasurface, microwave treatment

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Authors: Aryati Yashadhana, Ted Fields Jnr., Wendy Fernando, Kelvin Brown, Godfrey Blitner, Francis Hayes, Ruby Stanley, Brian Donnelly, Bridgette Jerrard, Anthea Burnett, Anthony B. Zwi

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Indigenous Australians experience some of the worst health outcomes globally, with life expectancy being significantly poorer than those of non-Indigenous Australians. This is largely attributed to preventable diseases such as diabetes (prevalence 39% in Indigenous Australian adults > 55 years), which is attributed to a raised risk of diabetic visual impairment and cataract among Indigenous adults. Our study aims to explore the interface between structural and sociocultural determinants and human agency, in order to understand how they impact (1) accessibility of eye health and chronic disease services and (2) the potential for Indigenous patients to achieve positive clinical eye health outcomes. We used Participatory Action Research methods, and aimed to privilege the voices of Indigenous people through community collaboration. Semi-structured interviews (n=82) and patient focus groups (n=8) were conducted by Indigenous Community-Based Researchers (CBRs) with diabetic Indigenous adults (> 40 years) in four remote communities in Australia. Interviews (n=25) and focus groups (n=4) with primary health care clinicians in each community were also conducted. Data were audio recorded, transcribed verbatim, and analysed thematically using grounded theory, comparative analysis and Nvivo 10. Preliminary analysis occurred in tandem with data collection to determine theoretical saturation. The principal investigator (AY) led analysis sessions with CBRs, fostering cultural and contextual appropriateness to interpreting responses, knowledge exchange and capacity building. Identified themes were conceptualised into three spheres of influence: structural (health services, government), sociocultural (Indigenous cultural values, distrust of the health system, ongoing effects of colonialism and dispossession) and individual (health beliefs/perceptions, patient phenomenology). Permeating these spheres of influence were three core determinants: economic disadvantage, health literacy/education, and cultural marginalisation. These core determinants affected accessibility of services, and the potential for patients to achieve positive clinical outcomes at every level of care (primary, secondary, tertiary). Our findings highlight the clinical realities of institutionalised and structural inequities, illustrated through the lived experiences of Indigenous patients and primary care clinicians in the four sampled communities. The complex determinants surrounding inequity in health for Indigenous Australians, are entrenched through a longstanding experience of cultural discrimination and ostracism. Secure and long term funding of Aboriginal Community Controlled Health Services will be valuable, but are insufficient to address issues of inequity. Rather, working collaboratively with communities to build trust, and identify needs and solutions at the grassroots level, while leveraging community voices to drive change at the systemic/policy level are recommended.

Keywords: indigenous, Australia, culture, public health, eye health, diabetes, social determinants of health, sociology, anthropology, health equity, aboriginal and Torres strait islander, primary care

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Authors: Liang Wang, Wei Zhang

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Nowadays, sustainable development has increasingly become an important research topic of engineering education. Existing research on Engineering Education for Sustainable Development (EESD) has highlighted the importance of perceptions for ethical responsibility to address sustainable development in practice. However, whether and how the professional engineering experience affects those perceptions has not been proved, especially in a Chinese context. Our study fills this gap by investigating the perceptions bias of EESD between experienced engineers and engineering students. We specifically examined what EESD means for experienced engineers and engineering students using a triple-dimensional model to understand if there are obvious differences between the two groups. Our goal is to make the benefits of these experiences more accessible in school context. The data (n=438) came from a questionnaire created and adapted from previously published studies containing 288 students from mechanical or civil engineering and 150 civil engineers with rich working experience, and the questionnaire was distributed during Fall 2020. T-test was used to find the difference in different dimensions between the two groups. The statistical results show that there is a significant difference in the perceptions of EESD between experienced engineers and inexperienced engineering students in China. Experienced engineers tend to consider sustainable development from ecological, economic, and social perspectives, while engineering students' answers focus more on ecology and ignore economic and social dimensions to some extend. The findings provide empirical evidence that professional experience is helpful to cultivate the cognition and ability of sustainable development in engineering education. The results of this work indicate that more practical content should be added to engineering education to promote sustainable development. In addition, for the design of engineering courses and professional practice systems for sustainable development, we should not only pay attention to the ecological aspects but also emphasize the coordination of ecological, economic, and socially sustainable development (e.g., engineer's ethical responsibility).

Keywords: engineering education, sustainable development, experienced engineers, engineering students

Procedia PDF Downloads 103

Authors: Ikele Chika Bright, Mgbenka Bernard Obialo, Ikele Chioma Faith

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Icthyophthiriasis is a prevalent protozoan (ectoparasite) mostly affecting cultured and aquarium fishes. The majority of the chemotherapeutants lack efficacy for completely eliminating Ich parasite without affecting the environment and they are not safe for human health. The present work is focused on the evaluating different immersion treatments of African catfish (Clarias gariepinus) infected with ichthyophthiriasis and treated with a non-chemical and environmental friendly parasiticides Moringa oleifera. A total number of 800 apparently healthy parasites free (examined) post juvenile catfish were obtained from a reputable farm, disinfected with potassium permanganate in a quarantine tank to remove any possible external parasites. The fish were further challenged with approximately 44,000 infective stages of theronts which were obtained through serial passages by cohabitation. Seven groups (A-G) of post Juvenile were used for the experiment which was carried out into three stages; Dips (60minutes), short term treatment (24-96h) and prolong bath treatment (0-15 days). The concentrations selected were dependent on the outcome of the LC50 of the plant material from which dose-dependent factors were used to select various concentrations of the treatment. In Dips treatment, group D-G were treated with 1,500mg/L, 2500mg/L., 3500mg/L and 4500mg/L, short-term treatment was treated with 150mg/L, 250mg/L, 350mg/L and 450mg/L and prolong bath was treated with 15mg/L, 25mg/L, 35mg/L and 45mg/L of the plant extract whereas group A, B and C were normal control, Ich- infested not treated and Ich- infested treated with standard drug (Acriflavin), respectively. The various types of treatment applied with corresponding concentrations showed almost complete elimination of the adult parasites (trophonts) both in the gills and the body smear, thereby making M. oleifera a potential parasiticides. There were serious pathological alterations in the skin and gills which are usually the main point for Ich parasites invasion but no significant morphological characteristics was noted among the treated groups subjected to different immersion treatment patterns. Epitheliocystis, aneurysm, oedema, hemorrhage, and localization of the adult parasite in the gills were the overall common observations made in the gills whereas degeneration of muscle fibre, dermatitis, hemorrhage, oedema, abscess formation and keratinisation were observed in the skin. However, there are no pathological changes in the control group. Moreover, biochemical parameters such as urea, creatinine, albumin., globulin, total protein, ALT, AST), blood chemistry (sodium, chloride, potassium, bicarbonate), antioxidants (CAT, SOD, GPx, LPO), enzymatic activities (myeloperoxidase, thioreadoxin reductase), Inflammatory response (C-reactive protein), Stress markers (lactate dehydrogenase), heamatological parameters (RBC, PCV, WBC, HB and differential count), lipid profile (total cholesterol, tryglycerides , high density lipoprotein and low density lipoprotein) all showed various significant (P<0.05) and no significant (P>0.05) responses among the Ich-infested fish treated under three immersion treatments. It is suggested that M. oleifera may serve as an alternatives to chemotherapeutants for control of Ichthyophthiriasis in African catfish Clarias gariepinus.

Keywords: Icthyophthirius multifilis, immersion treatment, pathophysiology, African catfish

Procedia PDF Downloads 391

Authors: Mirco Tarozzi, Giacomo Pignagnoli, Andrea Benedetti

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The design of planning maintenance of civil structures often requires the evaluation of their level of safety in order to be able to choose which structure, and in which measure, it needs a structural retrofit. This work deals with the evaluation of the stiffness reduction of a scaled steel deck due to the presence of localized damages. The dynamic tests performed on it have shown the variability of its main frequencies linked to the gradual reduction of its rigidity. This deck consists in a steel grillage of four secondary beams and three main beams linked to a concrete slab. This steel deck is 6 m long and 3 m wide and it rests on two abutments made of concrete. By processing the signals of the accelerations due to a random excitation of the deck, the main natural frequencies of this bridge have been extracted. In order to assign more reliable parameters to the numerical model of the deck, some load tests have been performed and the mechanical property of the materials and the supports have been obtained. The two external beams have been cut at one third of their length and the structural strength has been restored by the design of a bolted plate. The gradual loss of the bolts and the plates removal have made the simulation of localized damage possible. In order to define the relationship between frequency variation and loss in stiffness, the identification of its natural frequencies has been performed, before and after the occurrence of the damage, corresponding to each step. The study of the relationship between stiffness losses and frequency shifts has been reported in this paper: the square of the frequency variation due to the presence of the damage is proportional to the ratio between the rigidities. This relationship can be used to quantify the loss in stiffness of a real scale bridge in an efficient way.

Keywords: damage detection, dynamic test, frequency shifts, operational modal analysis, steel bridge

Procedia PDF Downloads 160

Authors: Sanaz Alizadeh, Yves Comeau, Arshath Abdul Rahim, Sunhasis Ghoshal

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The application of silver nanoparticles (AgNPs) in personal care products, various household and industrial products has resulted in an inevitable environmental exposure of such engineered nanoparticles (ENPs). Ag ENPs, released via household and industrial wastes, reach water resource recovery facilities (WRRFs), yet the fate and transport of ENPs in WRRFs and their potential risk in the biological wastewater processes are poorly understood. Accordingly, our main objective was to elucidate the impact of long-term continuous exposure to AgNPs on biological activity of aerobic wastewater biofilm. The fate, transport and toxicity of 10 μg.L-1and 100 μg.L-1 PVP-stabilized AgNPs (50 nm) were evaluated in an attached growth biological treatment process, using lab-scale moving bed bioreactors (MBBRs). Two MBBR systems for organic matter removal were fed with a synthetic influent and operated at a hydraulic retention time (HRT) of 180 min and 60% volumetric filling ratio of Anox-K5 carriers with specific surface area of 800 m2/m3. Both reactors were operated for 85 days after reaching steady state conditions to develop a mature biofilm. The impact of AgNPs on the biological performance of the MBBRs was characterized over a period of 64 days in terms of the filtered biodegradable COD (SCOD) removal efficiency, the biofilm viability and key enzymatic activities (α-glucosidase and protease). The AgNPs were quantitatively characterized using single-particle inductively coupled plasma mass spectroscopy (spICP-MS), determining simultaneously the particle size distribution, particle concentration and dissolved silver content in influent, bioreactor and effluent samples. The generation of reactive oxygen species and the oxidative stress were assessed as the proposed toxicity mechanism of AgNPs. Results indicated that a low concentration of AgNPs (10 μg.L-1) did not significantly affect the SCOD removal efficiency whereas a significant reduction in treatment efficiency (37%) was observed at 100 μg.L-1AgNPs. Neither the viability nor the enzymatic activities of biofilm were affected at 10 μg.L-1AgNPs but a higher concentration of AgNPs induced cell membrane integrity damage resulting in 31% loss of viability and reduced α-glucosidase and protease enzymatic activities by 31% and 29%, respectively, over the 64-day exposure period. The elevated intercellular ROS in biofilm at a higher AgNPs concentration over time was consistent with a reduced biological biofilm performance, confirming the occurrence of a nanoparticle-induced oxidative stress in the heterotrophic biofilm. The spICP-MS analysis demonstrated a decrease in the nanoparticles concentration over the first 25 days, indicating a significant partitioning of AgNPs into the biofilm matrix in both reactors. The concentration of nanoparticles increased in effluent of both reactors after 25 days, however, indicating a decreased retention capacity of AgNPs in biofilm. The observed significant detachment of biofilm also contributed to a higher release of nanoparticles due to cell-wall destabilizing properties of AgNPs as an antimicrobial agent. The removal efficiency of PVP-AgNPs and the biofilm biological responses were a function of nanoparticle concentration and exposure time. This study contributes to a better understanding of the fate and behavior of AgNPs in biological wastewater processes, providing key information that can be used to predict the environmental risks of ENPs in aquatic ecosystems.

Keywords: biofilm, silver nanoparticle, single particle ICP-MS, toxicity, wastewater

Procedia PDF Downloads 269

Authors: Chongyang Ye, Rong Liu

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Elastic compression stockings (ECSs) have been widely applied in prophylaxis and treatment of chronic venous insufficiency of lower extremities. The medical function of ECS is to improve venous return and increase muscular pumping action to facilitate blood circulation, which is largely determined by the complex interaction between the ECS and lower limb tissues. Understanding the mechanical transmission of ECS along the skin surface, deeper tissues, and vascular system is essential to assess the effectiveness of the ECSs. In this study, a three-dimensional (3D) finite element (FE) model of the leg-ECS system integrated with a 3D fluid-solid interaction (FSI) model of the leg-vein system was constructed to analyze the biomechanical properties of veins and soft tissues under different ECS compression. The Magnetic Resonance Imaging (MRI) of the human leg was divided into three regions, including soft tissues, bones (tibia and fibula) and veins (peroneal vein, great saphenous vein, and small saphenous vein). The ECSs with pressure ranges from 15 to 26 mmHg (Classes I and II) were adopted in the developed FE-FSI model. The soft tissue was assumed as a Neo-Hookean hyperelastic model with the fixed bones, and the ECSs were regarded as an orthotropic elastic shell. The interfacial pressure and stress transmission were simulated by the FE model, and venous hemodynamics properties were simulated by the FSI model. The experimental validation indicated that the simulated interfacial pressure distributions were in accordance with the pressure measurement results. The developed model can be used to predict interfacial pressure, stress transmission, and venous hemodynamics exerted by ECSs and optimize the structure and materials properties of ECSs design, thus improving the efficiency of compression therapy.

Keywords: elastic compression stockings, fluid-solid interaction, tissue and vein properties, prediction

Procedia PDF Downloads 113

Authors: Mattahias Maj, Fabio Tatzgern, Karl Adam, Damir Kahrimanovic, Markus Varga

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Torpedo ladles are necessary transport carriages in steel production to move the molten crude iron from the blast furnace to the steel refining plant. This requires the ladles to be high temperature resistant and insulate well to preserve the temperature and hold the risk of solidification at bay. Therefore, the involved refractories lining the inside of the torpedo ladles are chosen mostly according to their thermal properties, although wear of the materials by the liquid iron is also of major importance. In this work, we combined investigations of the thermal behaviour with wear studies of the lining over the whole lifetime of a torpedo ladle. Additional numerical simulations enabled a detailed model of the mechanical loads and temperature propagation at the various stations (heating, filling, emptying, cooling). The core of the investigation were detailed 3D measurements of the ladle’s cavity and thereby quantitative information of the wear progress at different time intervals during the lifetime of the ladles. The measurements allowed for a separation of different wear zones according to severity, namely the “splash zone” where the melt directly hits the ladle, the “melt zone” where during transport always liquid melt is present, and the “slag zone”, where the slag floats on the melt causing the most severe wear loss. Numerical simulations of the filling process were taken to calculate stress levels and temperature gradients, which led to the different onset of wear on those zones. Thermal imaging and punctual temperature measurements allowed for a study of the thermal consequences entailed by the wear onset. Additional “classical” damage analysis of the worn refractories complete the investigation. Thereby the wear mechanisms leading to the substantial wear loss were disclosed.

Keywords: high temperature, tribology, liquid-solid interaction, refractories, thermography

Procedia PDF Downloads 226

Authors: S. Koul, Joshua Adedamola

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Currently, the global concerning fact about electromagnetic pollution (EMP) is that it not only adversely affects human health but rather projects the malfunctioning of sensitive equipment both locally and at a global level. The market offers many incumbent technologies to solve the issues, but still, a processable sustainable material solution with acceptable limits for GHG emission is still at an exploratory stage. The present work offers a sustainable material solution with a wide range of processability in terms of a polymeric resin matrix and shielding operational efficiency across the electromagnetic spectrum, covering both ionizing and non-ionizing electromagnetic radiations. The present work offers an in-situ synthesized conducting polyaniline (PANI) in the presence of the hybrid dual dopant system with tuned conductivity and high shielding efficiency between 89 to 92 decibels, depending upon the EMI frequency range. The conductive polymer synthesized in the presence of a hybrid dual dopant system via the in-situ emulsion polymerization method offers a higher surface resistance of 1.0 ohms/cm with thermal stability up to 2450C in their powder form. This conductive polymer with a hybrid dual dopant system was used as a filler material with different polymeric thermoplastic resin systems for the preparation of conductive composites. Intrinsically Conductive polymeric (ICP) composites based on hybrid dual dopant systems were prepared using melt blending, extrusion, and finally by, compression molding processing techniques. ICP composites with hybrid dual dopant systems offered good mechanical, thermal, structural, weathering, and stable surface resistivity properties over a period of time. The preliminary shielding behavior for ICP composites between frequency levels of 10 GHz to 24GHZ offered a shielding efficiency of more than 90 dB.

Keywords: ICP, dopant, EMI, shielding

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Authors: Deepika Joshi

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Operations in automotive industry rely greatly on information shared between Supply Chain (SC) partners. This leads to efficient and effective management of SC activity. Automotive sector in India is growing at 14.2 percent per annum and has huge economic importance. We find that no study has been carried out on the role of information sharing in SC management of Indian automotive manufacturers. Considering this research gap, the present study is planned to establish the significance of information sharing in Indian auto-component supply chain activity. An empirical research was conducted for large scale auto component manufacturers from India. Twenty four Supply Chain Performance Indicators (SCPIs) were collected from existing literature. These elements belong to eight diverse but internally related areas of SC management viz., demand management, cost, technology, delivery, quality, flexibility, buyer-supplier relationship, and operational factors. A pair-wise comparison and an open ended questionnaire were designed using these twenty four SCPIs. The questionnaire was then administered among managerial level employees of twenty-five auto-component manufacturing firms. Analytic Network Process (ANP) technique was used to analyze the response of pair-wise questionnaire. Finally, twenty-five priority indexes are developed, one for each respondent. These were averaged to generate an industry specific priority index. The open-ended questions depicted strategies related to information sharing between buyers and suppliers and their influence on supply chain performance. Results show that the impact of information sharing on certain performance indicators is relatively greater than their corresponding variables. For example, flexibility, delivery, demand and cost related elements have massive impact on information sharing. Technology is relatively less influenced by information sharing but it immensely influence the quality of information shared. Responses obtained from managers reveal that timely and accurate information sharing lowers the cost, increases flexibility and on-time delivery of auto parts, therefore, enhancing the competitiveness of Indian automotive industry. Any flaw in dissemination of information can disturb the cycle time of both the parties and thus increases the opportunity cost. Due to supplier’s involvement in decisions related to design of auto parts, quality conformance is found to improve, leading to reduction in rejection rate. Similarly, mutual commitment to share right information at right time between all levels of SC enhances trust level. SC partners share information to perform comprehensive quality planning to ingrain total quality management. This study contributes to operations management literature which faces scarcity of empirical examination on this subject. It views information sharing as a building block which firms can promote and evolve to leverage the operational capability of all SC members. It will provide insights for Indian managers and researchers as every market is unique and suppliers and buyers are driven by local laws, industry status and future vision. While major emphasis in this paper is given to SC operations happening between domestic partners, placing more focus on international SC can bring in distinguished results.

Keywords: Indian auto component industry, information sharing, operations management, supply chain performance indicators

Procedia PDF Downloads 550

Authors: A. Aslihan Gokaltun, Martin L. Yarmush, Ayse Asatekin, O. Berk Usta

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In the last decade microfabrication processes including rapid prototyping techniques have advanced rapidly and achieved a fairly matured stage. These advances encouraged and enabled the use of microfluidic devices by a wider range of users with applications in biological separations, and cell and organoid cultures. Accordingly, a significant current challenge in the field is controlling biomolecular interactions at interfaces and the development of novel biomaterials to satisfy the unique needs of the biomedical applications. Poly(dimethylsiloxane) (PDMS) is by far the most preferred material in the fabrication of microfluidic devices. This can be attributed its favorable properties, including: (1) simple fabrication by replica molding, (2) good mechanical properties, (3) excellent optical transparency from 240 to 1100 nm, (4) biocompatibility and non-toxicity, and (5) high gas permeability. However, high hydrophobicity (water contact angle ~108°±7°) of PDMS often limits its applications where solutions containing biological samples are concerned. In our study, we created a simple, easy method for modifying the surface chemistry of PDMS microfluidic devices through the addition of surface-segregating additives during manufacture. In this method, a surface segregating copolymer is added to precursors for silicone and the desired device is manufactured following the usual methods. When the device surface is in contact with an aqueous solution, the copolymer self-organizes to expose its hydrophilic segments to the surface, making the surface of the silicone device more hydrophilic. This can lead to several improved performance criteria including lower fouling, lower non-specific adsorption, and better wettability. Specifically, this approach is expected to be useful for the manufacture of microfluidic devices. It is also likely to be useful for manufacturing silicone tubing and other materials, biomaterial applications, and surface coatings.

Keywords: microfluidics, non-specific protein adsorption, PDMS, PEG, copolymer

Procedia PDF Downloads 267

Authors: Aymen Laadhari

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During the last decade, an increasing number of contributions have been made in the fields of scientific computing and numerical methodologies applied to the study of the hemodynamics in the heart. In contrast, the numerical aspects concerning the interaction of pulsatile blood flow with highly deformable thin leaflets have been much less explored. This coupled problem remains extremely challenging and numerical difficulties include e.g. the resolution of full Fluid-Structure Interaction problem with large deformations of extremely thin leaflets, substantial mesh deformations, high transvalvular pressure discontinuities, contact between leaflets. Although the Lagrangian description of the structural motion and strain measures is naturally used, many numerical complexities can arise when studying large deformations of thin structures. Eulerian approaches represent a promising alternative to readily model large deformations and handle contact issues. We present a fully Eulerian finite element methodology tailored for the simulation of pulsatile blood flow in the aorta and sinus of Valsalva interacting with highly deformable thin leaflets. Our method enables to use a fluid solver on a fixed mesh, whilst being able to easily model the mechanical properties of the valve. We introduce a semi-implicit time integration scheme based on a consistent NewtonRaphson linearization. A variant of the classical Newton method is introduced and guarantees a third-order convergence. High-fidelity computational geometries are built and simulations are performed under physiological conditions. We address in detail the main features of the proposed method, and we report several experiments with the aim of illustrating its accuracy and efficiency.

Keywords: eulerian, level set, newton, valve

Procedia PDF Downloads 280

Authors: Dharmendra Pratap

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Large Cardamom (Amomum subulatum), family Zingiberaceae is an aromatic spice crop and has rich medicinal value. Large Cardamom is as synonymous to Sikkim as Tea is to Darjeeling. Since Sikkim alone contributes up to 88% of India's large cardamom production which is the world leader by producing over 50% of the global yield. However, the production of large cardamom has declined almost to half since last two decade. The economic losses have been attributed to two viral diseases namely, chirke and Foorkey. Chirke disease is characterized by light and dark green streaks on leaves. The affected leaves exhibit streak mosaic, which gradually coalesce, turn brown and eventually dry up. Excessive sprouting and formation of bushy dwarf clumps at the base of mother plants that gradually die characterize the foorkey disease. In our surveys in Sikkim–Darjeeling hill area during 2012-14, 40-45% of plants were found to be affected with foorkey disease and 10-15% with chirke. Mechanical and aphid transmission study showed banana as an alternate host for both the disease. For molecular identification, total genomic DNA and RNA was isolated from the infected leaf tissues and subjected to Rolling circle amplification (RCA) and RT-PCR respectively. The DNA concatamers produced in the RCA reaction were monomerized by different restriction enzymes and the bands corresponding to ~1 kb genomes were purified and cloned in the respective sites. The nucleotide sequencing results revealed the association of Nanovirus with the foorkey disease of large cardamom. DNA1 showed 74% identity with Replicase gene of FBNYV, DNA2 showed 77% identity with the NSP gene of BBTV and DNA3 showed 74% identity with CP gene of BBTV. The finding suggests the presence of a new species of nanovirus associated with foorkey disease of large cardamom in Sikkim and Darjeeling hills. The details of their epidemiology and other factors would be discussed.

Keywords: RCA, nanovirus, large cardamom, molecular virology and microbiology

Procedia PDF Downloads 494

Authors: Plinio Martins Dias Da Silva, Bruno Barbosa Castro, Andre Leibsohn Martins, Rosane Alves Fontes, Joao Vicente Martins de Magalhaes, Fernando Salatiel de Oliveira, Helga Elisabeth Pinheiro Schluter, Alexandre Zacharias Ignacio Pereira

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Inorganic scale is a relevant cause for production losses in offshore operations. In the development of pre-salt fields calcium carbonate crystallization, especially when the flow is submitted to abrupt depressurization, often cause problems in reservoir selectivity and production string obstruction. The conventional strategy for this kind of problem is to continuously inject chemicals to prevent precipitation. The low reliability of injection devices, which frequently fail, and the possibility of adopting downhole completion configurations which do not allow injection at the lower zones stimulated the industry to search for alternative mitigation strategies. The use of magnetic fields to help in minimizing the adhesion of calcium carbonate crystals to downhole surfaces. The proposed mechanisms include the effect of the magnetic field in generating fewer adhesive polymorphs (vaterite) in relation to the more stable ones (calcite). A discussion on this topic has been widely addressed in the literature. The goal of the present article is to describe the construction of real scale prototypes of a magnetic sub, a device to be attached to the production string to generate the necessary magnetic field to achieve the scale mitigation requirements. The strategy for magnetic and mechanical design is described. In addition, a protocol to establish the strategy for field installation in a field development project is detailed. The focus is to equip a given well with several subs and compare the production records with a correlation well with no subs installed. Finally, an update of the status of field installations is presented, with the proposed evaluation methodology customized for each field.

Keywords: magnetic subs, downhole, scale, inorganic, mitigation

Procedia PDF Downloads 11

Authors: Ahmed Bolaji Alarape, Oluwatobi Damilola Aba, Usman Shehu

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Wood plastic composite boards were made from sawn dust of Cordia alliodora and recycled polyethylene at a mixing ratio of 1.5ratio1, 2.5ratio1 and 3.5ratio1 and nominal densities of 600 kilograms per meter cube, 700 kilograms per meter cube, and 800 kilograms per meter cube, The material was hot pressed at 150-degree celsius to produce board of 250 millimeter by 250 millimeter by 6 millimeter of which 18 boards were produced. The experiment was subject to 3 by 3 factorial experiments in Completely Randomised Design (CRD). Analysis of variance and Duncan Multiple Range Test (DMRT) was adopted by 3 by 3 at 5 percent probability. The strength properties of the boards such as modulus of rupture (MOR) and modulus of elasticity (MOE) were investigated, while the dimensional properties of the board such as the water absorption (WA) and thickness swelling (TS) were as well determined after 12hrs and 24hrs of water immersion. The result showed that the mean values of MOE ranged from 9100.73 Newtons per square millimeters to 12086.96 Newtons per square millimeters while MOR values ranged from 48.26 Newtons per square millimeters to 103.09 Newtons per square millimeters. The values of WA and TS after 12hrs immersion ranged from 1.21 percent to 1.56 percent and 0.00 percent to 0.13 percent, respectively. The values of WA and TS after 24hrs of water immersion ranged from 1.66 percent to 2.99 percent and 0.02 percent to 0.18 percent, respectively. The higher the value of board density and the high-density polythene /sawdust ratio, the stronger, the stiffer and more dimensionally stable the wood plastic composite boards obtained. In addition, as the density of the board increases, the strength property of the boards increases. Hence the board will be suitable for internal construction materials.

Keywords: wood Plastic composite, modulus of rupture, modulus of elasticity, dimensional stability

Procedia PDF Downloads 180

Authors: Nathalie Bolding, Marta Montero, Joaquim Cevallos, Juan F. Martin-Lazaro

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Background: Inhaled epoprostenol (iEPO) have been shown to improve PaO2:FiO2 (PF) in combination with bronchodilators (BD). However, there is not an available device to deliver these two therapies concomitantly. We describe a new method to provide this therapy successfully. Objective: To evaluate the response to continuous nebulization of iEPO and intermittent nebulization of Salbutamol/Ipratropium bromide in adults with severe respiratory failure through a double mesh nebulisation in tandem. Methods: This observational study included two mechanical ventilated adults under hourly ventilatory, gasometrical and clinical measurements during 48h. Both had severe respiratory failure treated with continuous iEPO (50 – 200 micrograms/h) and BD (Salbutamol 2.5 mg and Ipratropium bromide 500 mcg every 6 hours) through double mesh nebulisation (Aerogen solo®) placed in tandem in the dry side of the humidificator. The primary endpoints were the variables associated with a positive response to this tandem nebulised therapy (PaFiO2 index, ROX index). Secondary endpoints were laboratory (ABG) clinical and ventilatory variables. Statistical analysis (SPSS v29) included linear regression and ANOVA. Results: The patients included (n=2) survived, both extubated, one after ECMO therapy. Severe acute respiratory failure had a positive response rate to continuous iEPO and intermittent BD: PaFiO2 increased (7.40 to 30.91; P75: 27%) as well as ROX index (2.91 to 11.43; P75: 33%). There was a linear correlation of improvement between iEPO with PaFiO2 (ANOVA, r=0.393, p<0.002) and ROX (r=0.419, p<0.001). iEPO+BD therapy did not show any complications. Conclusion: Continuous and intermittent mesh tandem nebulisation can be effectively delivered with this method with a positive effect in ventilatory parameters without observed complications. Randomised studies will be able to provide reassurance in this new therapy.

Keywords: tandem, mesh, nebulisers, pulmonary, vasoldilators, bronchodilators, respiratory, failure

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Authors: Kyong-Ku Yun, Seung-Yeon Han, Kyeo-Re Lee

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Silica fume which is a super-fine byproduct of ferrosilicon or silicon metal has a filling effect on micro-air voids or a transition zone in a hardened cement paste by appropriate mixing, placement, and curing. It, also, has a Pozzolan reaction which enhances the interior density of the hydrated cement paste through a formation of calcium silicate hydroxide. When substituting cement with silica fume, it improves water tightness and durability by filling effect and Pozzolan reaction. However, it needs high range water reducer or super-plasticizer to distribute silica fume into a concrete because of its finesses and high specific surface area. In order to distribute into concrete evenly, cement manufacturers make a pre-blended cement of silica fume and provide to a market. However, a special mixing procedures and another transportation charge another cost and this result in a high price of pre-blended cement of silica fume. The purpose of this dissertation was to investigate the dispersion of silica fume by air slurry and its effect on the mechanical properties of at ready-mixed concrete. The results are as follows: A dispersion effect of silica fume was measured from an analysis of standard deviation for compressive strength test results. It showed that the standard deviation decreased as the air bubble content increased, which means that the dispersion became better as the air bubble content increased. The test result of rapid chloride permeability test showed that permeability resistance increased as the percentages of silica fume increased, but the permeability resistance decreased as the quantity of mixing air bubble increased. The image analysis showed that a spacing factor decreased and a specific surface area increased as the quantity of mixing air bubble increased.

Keywords: cellular sprayed concrete, silica fume, deviation, permeability

Procedia PDF Downloads 132

Authors: Sadman Durlov, Aditya Ganesh-Ram, Hamidreza Hekmatjou, Md Najmus Salehin, Nora Shayesteh Ameri

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In the field of additive manufacturing, tungsten stands out for its exceptional resistance to high temperatures, making it an ideal candidate for use in extreme conditions. However, its inherent brittleness and vulnerability to thermal cracking pose significant challenges to its manufacturability. This study explores the microstructural evolution of tungsten processed through layer-wise rolling in laser powder bed fusion additive manufacturing, utilizing a comprehensive approach that combines advanced simulation techniques with empirical research. We aim to uncover the complex processes of plastic deformation and microstructural transformations, with a particular focus on the dynamics of grain size, boundary evolution, and phase distribution. Our methodology employs a combination of simulation and experimental data, allowing for a detailed comparison that elucidates the key mechanisms influencing microstructural alterations during the rolling process. This approach facilitates a deeper understanding of the material's behavior under additive manufacturing conditions, specifically in terms of deformation and recrystallization. The insights derived from this research not only deepen our theoretical knowledge but also provide actionable strategies for refining manufacturing parameters to improve the tungsten components' mechanical properties and functional performance. By integrating simulation with practical experimentation, this study significantly enhances the field of materials science, offering a robust framework for the development of durable materials suited for challenging operational environments. Our findings pave the way for optimizing additive manufacturing techniques and expanding the use of tungsten across various demanding sectors.

Keywords: additive manufacturing, layer wise rolling, refractory materials, in-situ microstructure modifications

Procedia PDF Downloads 61

Authors: Keerthi Katam, Abhinav B. Tirunaghari, Vinod Vadithya, Toshiyuki Shimizu, Satoshi Soda, Debraj Bhattacharyya

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Researchers worldwide are increasingly focusing on the removal of carbon and nutrient from wastewater using algal-bacterial hybrid systems. Algae produce oxygen during photosynthesis, which is taken up by heterotrophic bacteria for mineralizing organic carbon to carbon dioxide. This phenomenon reduces the net mechanical aeration requirement of aerobic biological wastewater treatment processes. Consequently, the treatment cost is also reduced. Microalgae also participate in the treatment process by taking up nutrient (N, P) from wastewater. Algal biomass, if harvested, can generate value-added by-products. The aim of the present study was to compare the performance of two systems - System A (mixed microalgae and bacteria) and System B (diatoms and bacteria) in treating kitchen wastewater (KWW). The test reactors were operated at five different solid retention times (SRTs) -2, 4, 6, 8, and 10-days in draw-and-fill mode. The KWW was collected daily from the dining hall-kitchen area of the Indian Institute of Technology Hyderabad. The influent and effluent samples were analyzed for total organic carbon (TOC), total nitrogen (TN) using TOC-L analyzer. A colorimetric method was used to analyze anionic surfactant. Phosphorus (P) and chlorophyll were measured by following standard methods. The TOC, TN, and P of KWW were in the range of 113.5 to 740 mg/L, 2 to 22.8 mg/L, and 1 to 4.5 mg/L, respectively. Both the systems gave similar results with 85% of TOC removal and 60% of TN removal at 10-d SRT. However, the anionic surfactant removal in System A was 99% and 60% in System B. The chlorophyll concentration increased with an increase in SRT in both the systems. At 2-d SRT, no chlorophyll was observed in System B, whereas 0.5 mg/L was observed in System A. At 10-d SRT, the chlorophyll concentration in System A was 7.5 mg/L, whereas it was 4.5 mg/L in System B. Although both the systems showed similar performance in treatment, the increase in chlorophyll concentration suggests that System A demonstrated a better algal-bacterial symbiotic relationship in treating KWW than System B.

Keywords: diatoms, microalgae, retention time, wastewater treatment

Procedia PDF Downloads 130