Search results for: chemical strength

Authors: Geun-Yeon Kim, S. P. Praveen Kumar, Kwon-Hee Lee

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A steering knuckle arm is the component that connects the steering system and suspension system. The structural performances such as stiffness, strength, and durability are considered in its design process. The former study suggested the lightweight design of a knuckle arm considering the structural performances and using the metamodel-based optimization. The six shape design variables were defined, and the optimum design was calculated by applying the kriging interpolation method. The finite element method was utilized to predict the structural responses. The suggested knuckle was made of the aluminum Al6082, and its weight was reduced about 60% in comparison with the base steel knuckle, satisfying the design requirements. Then, we investigated its manufacturability by performing foraging analysis. The forging was done as hot process, and the product was made through two-step forging. As a final step of its developing process, the durability is investigated by using the flexible dynamic analysis software, LS-DYNA and the pre and post processor, eta/VPG. Generally, a car make does not provide all the information with the part manufacturer. Thus, the part manufacturer has a limit in predicting the durability performance with the unit of full car. The eta/VPG has the libraries of suspension, tire, and road, which are commonly used parts. That makes a full car modeling. First, the full car is modeled by referencing the following information; Overall Length: 3,595mm, Overall Width: 1,595mm, CVW (Curve Vehicle Weight): 910kg, Front Suspension: MacPherson Strut, Rear Suspension: Torsion Beam Axle, Tire: 235/65R17. Second, the road is selected as the cobblestone. The road condition of the cobblestone is almost 10 times more severe than that of usual paved road. Third, the dynamic finite element analysis using the LS-DYNA is performed to predict the durability performance of the suggested knuckle arm. The life of the suggested knuckle arm is calculated as 350,000km, which satisfies the design requirement set up by the part manufacturer. In this study, the overall design process of a knuckle arm is suggested, and it can be seen that the developed knuckle arm satisfies the design requirement of the durability with the unit of full car. The VPG analysis is successfully performed even though it does not an exact prediction since the full car model is very rough one. Thus, this approach can be used effectively when the detail to full car is not given.

Keywords: knuckle arm, structural optimization, Metamodel, forging, durability, VPG (Virtual Proving Ground)

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Authors: Rajendra Chetty

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Decolonial aesthetics departs and delinks from colonial ideas about ‘the arts’ and the modernist/colonial work of aesthetics. Education is trapped in the western epistemic and hermeneutical vocabulary, hence it is necessary to introduce new concepts and work the entanglement between co-existing concepts. This paper will discuss the contribution of Ronnie Govender, a South African writer, to build decolonial sensibilities and delink from the grand narrative of the colonial and apartheid literary landscape in Govender’s text, At the Edge and other Cato Manor Stories. Govender uses the world of art to make a decolonial statement. Decolonial artists have to work in the entanglement of power and engage with a border epistemology. Govender’s writings depart from an embodied consciousness of the colonial wound and moves toward healing. Border thinking and doing (artistic creativity) is precisely the decolonial methodology posited by Linda T. Smith, where theory comes in the form of storytelling. Govender’s stories engage with the wounds infringed by racism and patriarchy, two pillars of eurocentric knowing, sensing, and believing that sustain a structure of knowledge. This structure is embedded in characters, institutions, languages that regulate and mange the world of the excluded. Healing is the process of delinking, or regaining pride, dignity, and humanity, not through the psychoanalytic cure, but the popular healer. The legacies of the community of Cato Manor that was pushed out of their land are built in his stories. Decoloniality then is a concept that carries the experience of liberation struggles and recognizes the strenuous conditions of marginalized people together with their strength, wisdom, and endurance. Govender’s unique performative prose reconstructs and resurrects the lives of the people of Cato Manor, their vitality and humor, pain and humiliation: a vibrant and racially integrated community destroyed by the regime’s notorious racial laws. The paper notes that Govender’s objective with his plays and stories was to open windows to both the pain and joy of life; a mission that is not didactic but to shine a torch on both mankind’s waywardness as well as its inspiring and often moving achievements against huge odds.

Keywords: Govender, decoloniality, delinking, exclusion, racism, Cato Manor

Procedia PDF Downloads 147

Authors: S. Ziaran, M. Musil, M. Cekan, O. Chlebo

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The paper analyzes the response of buildings and industrially structures on seismic waves (low frequency mechanical vibration) generated by blasting operations. The principles of seismic analysis can be applied for different kinds of excitation such as: earthquakes, wind, explosions, random excitation from local transportation, periodic excitation from large rotating and/or machines with reciprocating motion, metal forming processes such as forging, shearing and stamping, chemical reactions, construction and earth moving work, and other strong deterministic and random energy sources caused by human activities. The article deals with the response of seismic, low frequency, mechanical vibrations generated by nearby blasting operations on a residential home. The goal was to determine the fundamental natural frequencies of the measured structure; therefore it is important to determine the resonant frequencies to design a suitable modal damping. The article also analyzes the package of seismic waves generated by blasting (Primary waves – P-waves and Secondary waves S-waves) and investigated the transfer regions. For the detection of seismic waves resulting from an explosion, the Fast Fourier Transform (FFT) and modal analysis, in the frequency domain, is used and the signal was acquired and analyzed also in the time domain. In the conclusions the measured results of seismic waves caused by blasting in a nearby quarry and its effect on a nearby structure (house) is analyzed. The response on the house, including the fundamental natural frequency and possible fatigue damage is also assessed.

Keywords: building structure, seismic waves, spectral analysis, structural response

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Authors: Kulvinder Bajwa, Narsi R. Bishnoi

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Finding a sustainable alternative for today’s petrochemical industry is a major challenge facing by researchers, scientists, chemical engineers, and society at the global level. Microorganisms are considered to be sustainable feedstock for 3rd generation biofuel production. In this study, we have investigated the potential of a native bacterial strain isolated from a petrol contaminated site for the production of biodiesel. The bacterium was identified to be Rhodococcus opacus by biochemical test and 16S rRNA. Compositional analysis of bacterial biomass has been carried out by Fourier transform infrared spectroscopy (FTIR) in order to confirm lipid profile. Lipid and biomass were optimized by combination with Box Behnken design (BBD) of response surface methodology. The factors selected for the optimization of growth condition were glucose, yeast extract, and ammonium nitrate concentration. The experimental model developed through RSM in terms of effective operational factors (BBD) was found to be suitable to describe the lipid and biomass production, which indicated higher lipid and biomass with a minimum concentration of ammonium nitrate, yeast extract, and quite higher dose of glucose supplementation. Optimum results of the experiments were found to be 2.88 gL⁻¹ biomass and lipid content 38.75% at glucose 20 gL⁻¹, ammonium nitrate 0.5 gL⁻¹ and yeast extract 1.25 gL⁻¹. Furthermore, GCMS study revealed that Rhodococcus opacus has favorable fatty acid profile for biodiesel production.

Keywords: biofuel, Oleaginious bacteria, Rhodococcus opacus, FTIR, BBD, free fatty acids

Procedia PDF Downloads 130

Authors: Yu-Hong Lin

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Background: An adverse drug reaction (ADR) reported is an injury which caused by taking medicines. Sometimes the severity of ADR reported may be minor, but sometimes it could be a life-threatening situation. In order to provide healthcare professionals as a better reference in clinical practice, we do data collection and analysis from our hospital. Methods: This was a retrospective study of ADRs reported performed from 2014 to 2015 in our hospital in Taiwan. We collected assessment items of ADRs reported, which contain gender and age, occurring sources, Anatomical Therapeutic Chemical (ATC) classification of suspected drugs, types of adverse reactions, Naranjo score calculating by Naranjo Adverse Drug Reaction Probability Scale and so on. Results: The investigation included two hundred and seven ADRs reported. Most of ADRs reported were occurring in outpatient department (92%). The average age of ADRs reported was 65.3 years. Less than 65 years of age were in the majority in this study (54%). Majority of all ADRs reported were males (51%). According to ATC classification system, the major classification of suspected drugs was cardiovascular system (19%) and antiinfectives for systemic use (18%) respectively. Among the adverse reactions, Dermatologic Effects (35%) were the major type of ADRs. Also, the major Naranjo scores of all ADRs reported ranged from 1 to 4 points (91%), which represents a possible correlation between ADRs reported and suspected drugs. Conclusions: Definitely, ADRs reported is still an extremely important information for healthcare professionals. For that reason, we put all information of ADRs reported into our hospital's computer system, and it will improve the safety of medication use. By hospital's computer system, it can remind prescribers to think of information about patient's ADRs reported. No drugs are administered without risk. Therefore, all healthcare professionals should have a responsibility to their patients, who themselves are becoming more aware of problems associated with drug therapy.

Keywords: adverse drug reaction, Taiwan, healthcare professionals, safe use of medicines

Procedia PDF Downloads 225

Authors: Arturo S. Daag, Ira Karrel D. L. San Jose, Mike Gabriel G. Pedrosa, Ken Adrian C. Villarias, Rayfred P. Ingeniero, Cyrah Gale H. Rocamora, Margarita P. Dizon, Roland Joseph B. De Leon, Teresito C. Bacolcol

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The province of Leyte consists of various geomorphological landforms: These are: a) landforms of tectonic origin transect large part of the volcanic centers in upper Ormoc area; b) landforms of volcanic origin, several inactive volcanic centers located in Upper Ormoc are transected by Philippine Fault; c) landforms of volcano-denudational and denudational slopes dominates the area where most of the earthquake-induced landslide occurred; and d) Colluvium and alluvial deposits dominate the foot slope of Ormoc and Jaro-Pastrana plain. Earthquake ground acceleration and geotechnical properties of various landforms are crucial for landslide studies. To generate the landslide critical acceleration model of sliding block, various data were considered, these are: geotechnical data (i.e., soil and rock strength parameters), slope, topographic wetness index (TWI), landslide inventory, soil map, geologic maps for the calculation of the factor of safety. Horizontal-to-vertical spectral ratio (HVSR) surveying methods, refraction microtremor (ReMi), and three-component microtremor (3CMT) were conducted to measure site period and surface wave velocity as well as to create a soil thickness model. Critical acceleration model of various geomorphological unit using Remote Sensing, field geotechnical, geophysical, and geospatial data collected from the areas affected by the 06 July 2017 M6.5 Leyte earthquake. Spatial analysis of earthquake-induced landslide from the 06 July 2017, were then performed to assess the relationship between the calculated critical acceleration and peak ground acceleration. The observed trends proved helpful in establishing the role of critical acceleration as a determining factor in the distribution of co-seismic landslides.

Keywords: earthquake-induced landslide, remote sensing, geomorphology, seismic response

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Authors: K. H. Oyuntungalag, Scott Kenner, O. Erdenetuya

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The life cycle phases of mining projects are described in this guidance document, and includes initial phases (exploration, feasibility and planning), mine development (construction and operations), closure and reclamation. Initial phases relate to field programs and desktop studies intended to build the data and knowledge base, including the design of water management infrastructure and development during these initial phases. Such a model is essential to demonstrate that the water management plan (WMP) will provide adequate water for the mine operations and sufficient capacity for anticipated flows and volumes, and minimize environmental impacts on the receiving environment. The water and mass balance model must cover the whole mine life cycle, from the start of mine development to a date sufficiently far in the future where the reclaimed landscape is considered self- sustaining following complete closure of the mine (i.e., post- closure). The model simulates the movement of water within the components of the water management infrastructure and project operating areas, and calculates chemical loadings to each mine component. At Erdenet Mining company an initial water balance model reflecting the tailings dam, groundwater seepage and mine process water was developed in collaboration with Dr. Scott Kenner (visiting Fulbright scholar). From this preliminary study the following recommendations were made: 1. Develop a detailed groundwater model to simulate seepage from the tailings dam, 2. Establish an evaporation pan for improving evapotranspiration estimates, and 3. Measure changes in storage of water within the tailings dam and other water storage components within the mine processing.

Keywords: evapotranspiration , monitoring program, Erdenet mining, tailings dam

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Authors: Laroussi Chaabane, Emmanuel Beyou, Amel El Ghali, Mohammed Hassen V. Baouab

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The functionalization of graphene oxide sheets by ethylenediamine (EDA) was accomplished followed by the grafting of bis(2-pyridylmethyl)amino group (BPED) onto the activated graphene oxide sheets in the presence of chloroacetylchloride (CAC) produced the martial [(Go-EDA-CAC)-BPED]. The physic-chemical properties of [(Go-EDA-CAC)-BPED] composites were investigated by Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPs), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA). Moreover, [(Go-EDA-CAC)-BPED] was used for removing M(II) (where M=Cu, Ni and Co) ions from aqueous solutions using a batch process. The effect of pH, contact time and temperature were investigated. More importantly, the [(Go-EDA-CAC)-BPED] adsorbent exhibited remarkable performance in capturing heavy metal ions from water. The maximum adsorption capacity values of Cu(II), Ni(II) and Co(II) on the [(GO-EDA-CAC)-BPED] at the pH of 7 is 3.05 mmol.g⁻¹, 3.25 mmol.g⁻¹ and 3.05 mmol.g⁻¹ respectively. To examine the underlying mechanism of the adsorption process, pseudo-first, pseudo-second-order, and intraparticle diffusion models were fitted to experimental kinetic data. Results showed that the pseudo-second-order equation was appropriate to describe the three metal ions adsorption by [(Go-EDA-CAC)-BPED]. Adsorption data were further analyzed by the Langmuir, Freundlich, and Jossensadsorption approaches. Additionally, the adsorption properties of the [(Go-EDA-CAC)-BPED], their reusability (more than 10 cycles) and durability in the aqueous solutions open the path to removal of metal ions (Cu(II), Ni(II) and Co(II) from water solution. Based on the results obtained, we conclude that [(Go-EDA-CAC)-BPED] can be an effective and potential adsorbent for removing metal ions from an aqueous solution.

Keywords: graphene oxide, bis(2-pyridylmethyl)amino, adsorption kinetics, isotherms

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Authors: P. N. Guru, C. S. Patil

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The experiment was conducted during Kharif 2016 at Hingoni, Ahmednagar (dist.), Maharashtra (India) to evaluate the novel molecules of acaricides against mites in polyhouse capsicum. The study was planned with randomized block design (RBD) and included nine treatments replicated thrice with 30 m² each plot size. The crop (var. Bachata) was raised according to the standard package of practices except plant protection measures. The molecules viz., spiromesifen 22.9SC (95 gm a.i. ha⁻¹), fenpyroximate 5EC (15 gm a.i. ha⁻¹), hexythiazox 5.45EC (15 gm a.i. ha⁻¹), diafenthiuron 50WP (300 gm a.i. ha⁻¹), chlorfenapyr 10SC (75 gm a.i. ha⁻¹) were compared with a standard acaricide, dicofol 18.5EC (500 gm a.i. ha⁻¹) and biopesticides like Verticillium lecanii (2 g/l), Metarhizium anisopliae (2 g/l) and Neem oil 10,000ppm (2ml/l). In total three sprays were given after 30, 50 and 70 days after transplanting (DAT) at an interval of 20 days. The insecticidal solutions were prepared in water by diluting required concentration of chemical and applied using knapsack sprayer with hollow cone nozzle @ 500L of solution per hectare. The mites were counted per 4 cm² in three leaves from randomly selected five plants in each plot at 1 day before treatment (precount) and 1, 3, 5, 7, 10 and 15 days after treatment. The results revealed that fenpyroximate 5EC found best by recording significantly least mite population (2.72/4 cm² leaf area) followed by hexythiazox 5.45EC and spiromesifen 22.9SC (3.78 and 3.82 per 4 cm² leaf area, respectively) and followed by remaining treatments chlorfenapyr 10SC (4.13/4 cm² leaf area), diafenthiuron 50WP (4.32/4 cm² leaf area), and dicofol 18.5EC (4.48/4 cm² leaf area). Among the biopesticides tested Neem oil and Verticillium lecanii were found to be superior to Metarhizium anisopliae. Overall, newer molecules like fenpyroximate, hexythiazox, spiromesifen, diafenthiuron, and Chlorfenapyr can be used for the effective management of mites under polyhouse capsicum.

Keywords: acaricides, capsicum, mites, spiromesifen

Procedia PDF Downloads 157

Authors: Benchouala Amira, Bojic Clement, Poupin Pascal, Cossu Leguille-carole

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The objective of this study is to evaluate in vitro the cytotoxic and androgenic potential of several antifungal molecules (amphotericin B, econazole, ketoconazole and miconazole) on MDA-Kb2 cell lines. This biological model is an effective tool for the detection of endocrine disruptors because it responds well to the main agonist of the androgen receptor (testosterone) and also to an antagonist: flutamide. The cytotoxicity of each chemical compound tested was measured using an MTT assay (tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) which measures the activity of the reductase function of mitochondrial succinate dehydrogenase enzymes of cultured cells. This complementary cytotoxicity test is essential to ensure that the effects of reduction in luminescence intensity observed during androgenic tests are only attributable to the anti-androgenic action of the compounds tested and not to their possible cytotoxic properties. Tests of the androgenic activity of antifungals show that these compounds do not have the capacity to induce transcription of the luciferase gene. These compounds do not exert an androgenic effect on MDA-Kb2 cells in culture for the environmental concentrations tested. The addition of flutamide for the same tested concentrations of antifungal molecules reduces the luminescence induced by amphotericin B, econazole and miconazole, which is explained by a strong interaction of these molecules with flutamide which may have a greater toxic effect than when tested alone. The cytotoxicity test shows that econazole and ketoconazole can cause cell death at certain concentrations tested. This cell mortality is perhaps induced by a direct or indirect action on deoxyribonucleic acid (DNA), ribonucleic acid (RNA) or proteins necessary for cell division.

Keywords: cytotoxicity, androgenic potential, antifungals, MDA-Kb2

Procedia PDF Downloads 38

Authors: Stefanie Ficht, Lukas Schübel, Magdalena Kleybolte, Markus Eblenkamp, Jana Steger, Dirk Wilhelm, Petra Mela

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Although 3D printing as transformative technology has become of increasing interest in the medical field and the demand for biodegradable polymers has developed to a considerable extent, there are only a few additively manufactured, biodegradable implants on the market. Additionally, the sterilization of such implants and its side effects on degradation have still not been sufficiently studied. Within this work, thermosensitive poly p-dioxanone (PPDO) samples were printed with fused filament fabrication (FFF) and investigated. Subsequently, H₂O₂ plasma and gamma radiation were used as low-temperature sterilization techniques and compared among each other and the control group (no sterilization). In order to assess the effect of different sterilization on the degradation behavior of PPDO, the samples were immersed in phosphate-buffered solution (PBS) over 28 days, and surface morphology, thermal properties, molecular weight, inherent viscosity, and mechanical properties were examined at regular time intervals. The study demonstrates that PPDO was printed with great success and that thermal properties, molecular weight (Mw), and inherent viscosity (IV) were not significantly affected by the printing process itself. H₂O₂ plasma sterilization did not significantly harm the thermosensitive polymer, while gamma radiation lowered IV and Mw statistically significantly compared to the control group (p < 0.001). During immersion in PBS, a decrease in Mw and mechanical strength occurred for all samples. However, gamma sterilized samples were affected to a much higher extent compared to the two other sample groups both in final values and timeline. This was confirmed by scanning electron microscopy showing no changes of surface morphology of (non-sterilized) control samples, first microcracks appearing on plasma sterilized samples after two weeks while being present on gamma sterilized samples already immediately after radiation to then further deteriorate over immersion duration. To conclude, we demonstrated that FFF and H₂O₂ plasma sterilization are well suited for processing thermosensitive, biodegradable polymers used for the development of innovative short-term medical applications.

Keywords: additive manufacturing, sterilization, biodegradable, thermosensitive, medical application

Procedia PDF Downloads 117

Authors: Tooba Aslam, Efthalia Chatzisymeon

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Untreated Municipal Wastewater (MWW) is renowned as the utmost harmful pollution caused to environmental water due to the high presence of nutrients and organic contaminants. Removal of Chemical Oxygen Demand (COD) from synthetic as well as municipal wastewater is investigated by using acid mine drainage as a source of iron to initiate the solar photo-Fenton treatment of municipal wastewater. In this study, Acid Mine Drainage (AMD) and different minerals enriched in iron, such as goethite, hematite, magnetite, and magnesite, have been used as the source of iron to initiate the photo-Fenton process. Co-treatment of real municipal wastewater and acid mine drainage /minerals is widely examined. The effects of different parameters such as minerals recovery from AMD, AMD as a source of iron, H₂O₂ concentration, and COD concentrations on the COD percentage removal of the process are studied. The results show that, out of all the four minerals, only hematite (1g/L) could remove 30% of the pollutants at about 100 minutes and 1000 ppm of H₂O₂. The addition of AMD as a source of iron is performed and compared with both synthetic as well as real wastewater from South Africa under the same conditions, i.e., 1000 ppm of H₂O₂, ambient temperature, 2.8 pH, and solar simulator. In the case of synthetic wastewater, the maximum removal (56%) is achieved with 50 ppm of iron (AMD source) at 160 minutes. On the other hand, in real wastewater, the removal efficiency is 99% with 30 ppm of iron at 90 minutes and 96% with 50 ppm of iron at 120 minutes. In conclusion, overall, the co-treatment of AMD and MWW by solar photo-Fenton treatment appears to be an effective and promising method to remove organic materials from Municipal wastewater.

Keywords: municipal wastewater treatment, acid mine drainage, co-treatment, COD removal, solar photo-Fenton, circular economy

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Authors: Guo Lei, Wang Yue, Nakamura Yoshio, Shi Ji

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Recently, perpendicular exchange bias (PEB) is introduced as an active topic attracting continuous efforts. Since its discovery, extrinsic control of PEB has been proposed, due to its scientific significance in spintronic devices and potential application in high density magnetic random access memory with perpendicular magnetic tunneling junction (p-MTJ). To our knowledge, the researches aiming to controlling PEB so far are focused mainly on enhancing the interfacial exchange coupling by adjusting the FM/AFM interface roughness, or optimizing the crystalline structures of FM or AFM layer by employing different seed layers. In present work, the effects of magnetoelastically induced PMA on PEB have been explored in [CoO5nm/CoPt5nm]5 multilayer films. We find the PMA strength of FM layer also plays an important role on PEB at the FM/AFM interface and it is effective to control PEB of [CoO5nm/CoPt5nm]5 multilayer films by changing the magnetoelastically induced PMA of CoPt layer. [CoO5nm/CoPt5nm]5 multilayer films were deposited by magnetron sputtering on fused quartz substrate at room temperature, then annealed at 100°C, 250°C, 300°C and 375°C for 3h, respectively. XRD results reveal that all the samples are well crystallized with preferred fcc CoPt (111) orientation. The continuous multilayer structure with sharp component transition at the CoO5nm/CoPt5nm interface are identified clearly by transmission electron microscopy (TEM), x-ray reflectivity (XRR) and atomic force microscope (AFM). CoPt layer in-plane tensile stress is calculated by sin2φ method, and we find it increases gradually upon annealing from 0.99 GPa (as-deposited) up to 3.02 GPa (300oC-annealed). As to the magnetic property, significant enhancement of PMA is achieved in [CoO5nm/CoPt5nm]5 multilayer films after annealing due to the increase of CoPt layer in-plane tensile stress. With the enhancement of magnetoelastically induced PMA, great improvement of PEB is also achieved in [CoO5nm/CoPt5nm]5 multilayer films, which increases from 130 Oe (as-deposited) up to 1060 Oe (300oC-annealed), showing the same change tendency as PMA and the strong correlation with CoPt layer in-plane tensile stress. We consider it is the increase of CoPt layer in-plane tensile stress that leads to the enhancement of PMA, and thus the enhancement of magnetoelastically induced PMA results in the improvement of PEB in [CoO5nm/CoPt5nm]5 multilayer films.

Keywords: perpendicular exchange bias, magnetoelastically induced perpendicular magnetic anisotropy, CoO5nm/CoPt5nm]5 multilayer film with in-plane stress, perpendicular magnetic tunneling junction

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Authors: Milda A. Cruz-Huaranga, Natalí Carbo-Bustinza, Javier Linkolk López-Gonzales, K. Depaz, Gina M. Tito T., Soledad Torres-Calderón

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The objective of this study was to improve water quality in the “La Mansión” pond in order to irrigate green spaces on the Peruvian Union University campus (Lima, Peru) using the aquatic species Eichhornia Crassipes. Furthermore, tree trimming and cleaning activities were performed that reduced water pollution caused by organic deposits and feathers from wild birds. The impaired waterbody is located on the campus of the Peruvian Union University, 580 meters above sea level, with a volume of 6,405.336 m3, an area of 3,050.16 m2, 256.81 m perimeter, and 0.12 m3/s input flow. Seven 1.8 m2 floating systems were implemented, with 12 common water hyacinth plants in each system. Before implementing this system, a water quality analysis was performed to analyse the physical-chemical, microbiological, and organoleptic parameters. The pre-analysis revealed the pond’s critical condition, with electrical conductivity: 556 mg/l; phosphate: < 0.5; pH: 7.06; total solids: 412 mg/l; arsenic: <0.01; lead: 0.115; BOD5: 14; COD: 16.94; dissolved oxygen: 13; total coliforms: 24000 MCL/100 ml; and thermo-tolerant coliforms: 11000 MCL/100 ml. After implementing the system, the following results were obtained: EC: 495 mg/l; DO:9.2 mg/l; TS: 235 mg/l; BOD5: 7.7; COD: 8.47; Pb: 0.001 mg/l; TC: 460 MCL/100 ml; FC: 240 MCL/100 ml. Thus, we confirmed that the system is 78.79% efficient regarding the Peruvian ECA (Environmental Quality Standards) established for water according to DS #015-2015-MINAM. Therefore, the water is suitable for plant irrigation. Finally, we concluded that treating wastewater with the species Eichhornia Crassipes is efficient since an improvement was achieved in the impaired waterbody.

Keywords: Eichhornia crassipes, plantlets, cleaning, impaired waterbody, pond

Procedia PDF Downloads 133

Authors: Sushil Kumar Singh, Ashok Kumar, Ankit Ganeshpurkar, Ravi Singh, Devendra Kumar

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In spectrum of neurodegenerative diseases, Alzheimer’s disease (AD) is characterized by the presence of amyloid β plaques and neurofibrillary tangles in the brain. It results in cognitive and memory impairment due to loss of cholinergic neurons, which is considered to be one of the contributing factors. Donepezil, an acetylcholinesterase (AChE) inhibitor which also inhibits butyrylcholinesterase (BuChE) and improves the memory and brain’s cognitive functions, is the most successful and prescribed drug to treat the symptoms of AD. The present work is based on designing of the selective BuChE inhibitors using computational techniques. In this work, machine learning models were trained using classification algorithms followed by screening of diverse chemical library of compounds. The various molecular modelling and simulation techniques were used to obtain the virtual hits. The amide derivatives of 4-(phenylsulfonamido) benzoic acid were synthesized and characterized using 1H & 13C NMR, FTIR and mass spectrometry. The enzyme inhibition assays were performed on equine plasma BuChE and electric eel’s AChE by method developed by Ellman et al. Compounds 31, 34, 37, 42, 49, 52 and 54 were found to be active against equine BuChE. N-(2-chlorophenyl)-4-(phenylsulfonamido)benzamide and N-(2-bromophenyl)-4-(phenylsulfonamido)benzamide (compounds 34 and 37) displayed IC50 of 61.32 ± 7.21 and 42.64 ± 2.17 nM against equine plasma BuChE. Ortho-substituted derivatives were more active against BuChE. Further, the ortho-halogen and ortho-alkyl substituted derivatives were found to be most active among all with minimal AChE inhibition. The compounds were selective toward BuChE.

Keywords: Alzheimer disease, butyrylcholinesterase, machine learning, sulfonamides

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Authors: Diriba Gemechu, Lamessa Abebe

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The aim of this study was to examine the effect of cooperative learning method on student’s academic achievement and on the achievement level over a usual method in teaching different topics of mathematics. The study also examines the perceptions of students towards cooperative learning. Cooperative learning is the instructional strategy in which pairs or small groups of students with different levels of ability work together to accomplish a shared goal. The aim of this cooperation is for students to maximize their own and each other learning, with members striving for joint benefit. The teacher’s role changes from wise on the wise to guide on the side. Cooperative learning due to its influential aspects is the most prevalent teaching-learning technique in the modern world. Therefore the study was conducted in order to examine the effect of cooperative learning on the academic achievement of grade 9 students in Mathematics in case of Mettu secondary school. Two sample sections are randomly selected by which one section served randomly as an experimental and the other as a comparison group. Data gathering instruments are achievement tests and questionnaires. A treatment of STAD method of cooperative learning was provided to the experimental group while the usual method is used in the comparison group. The experiment lasted for one semester. To determine the effect of cooperative learning on the student’s academic achievement, the significance of difference between the scores of groups at 0.05 levels was tested by applying t test. The effect size was calculated to see the strength of the treatment. The student’s perceptions about the method were tested by percentiles of the questionnaires. During data analysis, each group was divided into high and low achievers on basis of their previous Mathematics result. Data analysis revealed that both the experimental and comparison groups were almost equal in Mathematics at the beginning of the experiment. The experimental group out scored significantly than comparison group on posttest. Additionally, the comparison of mean posttest scores of high achievers indicates significant difference between the two groups. The same is true for low achiever students of both groups on posttest. Hence, the result of the study indicates the effectiveness of the method for Mathematics topics as compared to usual method of teaching.

Keywords: academic achievement, comparison group, cooperative learning, experimental group

Procedia PDF Downloads 243

Authors: S. Ghosh, L. Ramos, A. N. Kouamé, A.-L. Teillout, H. Remita

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Catalytic materials have attracted continuous attention due to their promising applications in a variety of energy and environmental applications including clean energy, energy conversion and storage, purification and separation, degradation of pollutants and electrochemical reactions etc. With the advanced synthetic technologies, polymer nanostructures and nanocomposites can be directly synthesized through soft template mediated approach using swollen hexagonal mesophases and modulate the size, morphology, and structure of polymer nanostructures. As an alternative to conventional catalytic materials, one-dimensional PDPB polymer nanostructures shows high photocatalytic activity under visible light for the degradation of pollutants. These photocatalysts are very stable with cycling. Transmission electron microscopy (TEM), and AFM-IR characterizations reveal that the morphology and structure of the polymer nanostructures do not change after photocatalysis. These stable and cheap polymer nanofibers and metal polymer nanocomposites are easy to process and can be reused without appreciable loss of activity. The polymer nanocomposites formed via one pot chemical redox reaction with 3.4 nm Pd nanoparticles on poly(diphenylbutadiyne) (PDPB) nanofibers (30 nm). The reduction of Pd (II) ions is accompanied by oxidative polymerization leading to composites materials. Hybrid Pd/PDPB nanocomposites used as electrode materials for the electrocatalytic oxidation of ethanol without using support of proton exchange Nafion membrane. Hence, these conducting polymer nanofibers and nanocomposites offer the perspective of developing a new generation of efficient photocatalysts for environmental protection and in electrocatalysis for fuel cell applications.

Keywords: conducting polymer, swollen hexagonal mesophases, solar photocatalysis, electrocatalysis, water depollution

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Authors: Babar Ali, Mohammad Rashid, Showkat Rasool Mir, Mohammad Ali, Saiba Shams

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Background: The plant Camellia sinensis (Theaceae) is an evergreen shrub indigenous to Assam (India) and parts of China and Japan. Traditional Chinese medicine has recommended green tea for headaches, body aches and pains, digestion, enhancement of immune defense, detoxification, as an energizer and to prolong life. The leaves have more than 700 chemical constituents, among which flavanoids, amino acids, vitamins (C, E, K), caffeine and polysaccharides. Adulteration and substitution may affect the quality of formulation containing tea leaves. Standardization of medicinal preparation is essential for further therapeutic results and for global acceptance. Hence, chromatographic fingerprint profiles were carried out for establishing the standards. Materials and methods: TLC studies for methanolic extracts of the leaves of Camellia sinensis were carried out in a new developed solvent system, Toluene: Ethyl acetate: Formic acid (7:3:1). TLC plates were dried in air, visualized in UV at wavelengths 254 nm and 366 nm and photographed. Results: Results provide valuable clue regarding their polarity and selection of solvents for separation of phytochemicals. Fingerprinting of methanolic extract of Camellia sinensis leaves revealed the presence of various phytochemicals in UV at 254 nm and 366 nm. Conclusion: Fingerprint profile is quite helpful in setting up of standards and thus to keep a check on intentional/unintentional adulteration. TLC offers major advantages over other conventional chromatographic techniques such as unsurpassed flexibility (esp. stationary and mobile phase), choice of detection wavelength, user friendly, rapid and cost effective.

Keywords: Cammelia sinensis Linn., standardization, methanolic extract, thin layer chromatography

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Authors: Mustapha Kamel Mihoubi, Essadik Kerkar, Abdelhamid Hebbouche

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According to the randomness of most of the factors affecting the stability of a gravity dam, probability theory is generally used to TESTING the risk of failure and there is a confusing logical transition from the state of stability failed state, so the stability failure process is considered as a probable event. The control of risk of product failures is of capital importance for the control from a cross analysis of the gravity of the consequences and effects of the probability of occurrence of identified major accidents and can incur a significant risk to the concrete dam structures. Probabilistic risk analysis models are used to provide a better understanding the reliability and structural failure of the works, including when calculating stability of large structures to a major risk in the event of an accident or breakdown. This work is interested in the study of the probability of failure of concrete dams through the application of the reliability analysis methods including the methods used in engineering. It is in our case of the use of level II methods via the study limit state. Hence, the probability of product failures is estimated by analytical methods of the type FORM (First Order Reliability Method), SORM (Second Order Reliability Method). By way of comparison, a second level III method was used which generates a full analysis of the problem and involving an integration of the probability density function of, random variables are extended to the field of security by using of the method of Mont-Carlo simulations. Taking into account the change in stress following load combinations: normal, exceptional and extreme the acting on the dam, calculation results obtained have provided acceptable failure probability values which largely corroborate the theory, in fact, the probability of failure tends to increase with increasing load intensities thus causing a significant decrease in strength, especially in the presence of combinations of unique and extreme loads. Shear forces then induce a shift threatens the reliability of the structure by intolerable values of the probability of product failures. Especially, in case THE increase of uplift in a hypothetical default of the drainage system.

Keywords: dam, failure, limit state, monte-carlo, reliability, probability, sliding, Taylor

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Authors: Revoti Prasad Bora, Saurabh Yadav, Nikita Katyal

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In the context of educational data mining, the use case of extracting information from images containing both text and diagrams is of high importance. Hence, document analysis requires the extraction of diagrams from such images and processes the text and diagrams separately. To the author’s best knowledge, none among plenty of approaches for extracting tables, figures, etc., suffice the need for real-time processing with high accuracy as needed in multiple applications. In the education domain, diagrams can be of varied characteristics viz. line-based i.e. geometric diagrams, chemical bonds, mathematical formulas, etc. There are two broad categories of approaches that try to solve similar problems viz. traditional computer vision based approaches and deep learning approaches. The traditional computer vision based approaches mainly leverage connected components and distance transform based processing and hence perform well in very limited scenarios. The existing deep learning approaches either leverage YOLO or faster-RCNN architectures. These approaches suffer from a performance-accuracy tradeoff. This paper proposes a U-Net based architecture that formulates the diagram extraction as a segmentation problem. The proposed method provides similar accuracy with a much faster extraction time as compared to the mentioned state-of-the-art approaches. Further, the segmentation mask in this approach allows the extraction of diagrams of irregular shapes.

Keywords: computer vision, deep-learning, educational data mining, faster-RCNN, figure extraction, image segmentation, real-time document analysis, text extraction, U-Net, YOLO

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Authors: Janeth Chepkemoi, Richard Onwonga, Noel Templer, Elkana Kipkoech, Angela Gitau

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Conventional agriculture is one of the leading causes of land degradation, threatening the sustainability of food production. Organic farming promotes practices that have the potential of feeding the world while also promoting ecological health. A study was therefore carried out with the aim of conceptualizing how such farming systems are contributing to ecological health in Trans Nzoia County. 71 farmers were interviewed and data was collected on parameters such as land preparation, agroforestry, soil fertility management, soil and water conservation, and pests and diseases. A soil sample was also collected from each farm for laboratory analysis. Data collected were analyzed using Microsoft Excel and SPSS version 21. Results showed that 66% of the respondents practiced organic farming whereas 34% practiced conventional farming. Intercropping and crop rotations were the most common cropping systems and the most preferred land preparation tools among both organic and conventional farmers were tractors and hand hoes. Organic farms fared better in agroforestry, organic soil amendments, land and water conservation, and soil chemical properties. Pests and disease, however, affected organic farms more than conventional. The average nitrogen (%), K (Cmol/ kg and P (ppm) of organic soils were 0.26, 0.7 and 26.18 respectively, conventional soils were 0.21, 0.66 and 22.85. Soil organic carbon content of organic farms averaged a higher percentage of 2.07% as compared to 1.91 for the conventional. In conclusion, most farmers in Trans Nzoia County had transitioned into ecologically friendly farming practices that improved the quality and health of the soil and therefore promoted its sustainability.

Keywords: organic farming, conventional farming, ecological health, soil health

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Authors: Parthiban Srinivasan

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With recent advances in computational power and access to enough data in biosciences, artificial intelligence methods are increasingly being used in drug discovery research. These methods are essentially a series of advanced statistics based exercises that review the past to indicate the likely future. Our goal is to develop a model that accurately predicts biological activity and toxicity parameters for novel compounds. We have compiled a robust library of over 150,000 chemical compounds with different pharmacological properties from literature and public domain databases. The compounds are stored in simplified molecular-input line-entry system (SMILES), a commonly used text encoding for organic molecules. We utilize an automated process to generate an array of numerical descriptors (features) for each molecule. Redundant and irrelevant descriptors are eliminated iteratively. Our prediction engine is based on a portfolio of machine learning algorithms. We found Random Forest algorithm to be a better choice for this analysis. We captured non-linear relationship in the data and formed a prediction model with reasonable accuracy by averaging across a large number of randomized decision trees. Our next step is to apply deep neural network (DNN) algorithm to predict the biological activity and toxicity properties. We expect the DNN algorithm to give better results and improve the accuracy of the prediction. This presentation will review all these prominent machine learning and deep learning methods, our implementation protocols and discuss these techniques for their usefulness in biomedical and health informatics.

Keywords: deep learning, drug discovery, health informatics, machine learning, toxicity prediction

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Authors: Niranjan Devkota , Ram Kumar Phuya, Durga Lal Shreshta

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This paper estimates cost and benefit of adoption of climate change adaptation options available to the rural rice farmers of Nepal. Adoption of adaptation strategies, intensity of use of adaptation options, identification of labor and non-labor cost and finally per unit cost and benefit analysis of climate change adaptation were made. Multi-stage sampling technique was used to source respondents for the study and used structured questionnaire techniques to collect data from 773 households from seven districts; 3 from Terai and 4 from Hilly region of Nepal. The result revealed that there are 13 major adaptation options rice farmers practice in order to protect themselves from climatic risk. Among the given adaptation options, the first three popular adaptation options practiced by rice farmers are (i) increasing use of chemical fertilizer (60.93%) (ii) use of climate smart verities (49.29%) and (iii) change in nursery date (32.08%). Adaptation cost is obvious, based on that, the first three costly adaptation options are the alternative irrigation practice which incurred average cost of US $69.95 (US$ 1 = 102.84 Nepalese Rupees) followed by a denser plantation of local seeds ($ 20.69) and using climate smart varieties ($ 18.06). 88% farmers practiced more than one adaptation strategies on the same farm with the aim of reducing the effect of extreme climatic conditions. Total cost and revenue revealed that per unit total cost ranges from $28.34 to $32.79 whereas per unit total revenue ranges $33.4 to $49.02. Surprisingly, it is observed that farmers who do not adopt any adaptation options are able to receive highest income from per unit production. As Net Present Value (NPV) is positive and Benefit Cost Ration (BCR) is greater than one for every adaptation options that indicates the available adaptation options are profitable to the rice farmers.

Keywords: climate change, adaptation options, cost benefit analysis, rural rice farmers, Nepal

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Authors: Yuanrui Xu, Zailin Yang, Yunqiu Song, Guanxixi Jiang

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It is an important subject of seismology on the influence of local topography on ground motion during earthquake. In mountainous areas with complex terrain, the construction of the tunnel is often the most effective transportation scheme. In these projects, the local terrain can be simplified into hills with different shapes, and the underground tunnel structure can be regarded as a subsurface cavity. The presence of the subsurface cavity affects the strength of the rock mass and changes the deformation and failure characteristics. Moreover, the scattering of the elastic waves by underground structures usually interacts with local terrains, which leads to a significant influence on the surface displacement of the terrains. Therefore, it is of great practical significance to study the surface displacement of local terrains with underground tunnels in earthquake engineering and seismology. In this work, the region is divided into three regions by the method of region matching. By using the fractional Bessel function and Hankel function, the complex function method, and the wave function expansion method, the wavefield expression of SH waves is introduced. With the help of a constitutive relation between the displacement and the stress components, the hoop stress and radial stress is obtained subsequently. Then, utilizing the continuous condition at different region boundaries, the undetermined coefficients in wave fields are solved by the Fourier series expansion and truncation of the finite term. Finally, the validity of the method is verified, and the surface displacement amplitude is calculated. The surface displacement amplitude curve is discussed in the numerical results. The results show that different parameters, such as radius and buried depth of the tunnel, wave number, and incident angle of the SH wave, have a significant influence on the amplitude of surface displacement. For the underground tunnel, the increase of buried depth will make the response of surface displacement amplitude increases at first and then decreases. However, the increase of radius leads the response of surface displacement amplitude to appear an opposite phenomenon. The increase of SH wave number can enlarge the amplitude of surface displacement, and the change of incident angle can obviously affect the amplitude fluctuation.

Keywords: method of region matching, scattering of SH wave, subsurface cavity, trapezoidal hill

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Authors: Timothy E. Frank, Peter J. Amaddio, Elizabeth D. Decko, Alexis M. Tri, Darcy A. Farrell, Cole M. Landes

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Ultra high performance concrete (UHPC) is a class of cementitious composites with a relatively large percentage of cement generating high compressive strength. Additionally, UHPC contains disbursed fibers, which control crack width, carry the tensile load across narrow cracks, and limit spalling. These characteristics lend themselves to a wide range of structural applications when UHPC members are reinforced with longitudinal steel. Efficient use of fibers and longitudinal steel is required to keep lifecycle cost competitive in reinforced UHPC members; this requires full utilization of both the compressive and tensile qualities of the reinforced cementitious composite. The objective of this study is to investigate the shear response of steel-reinforced UHPC beams to guide design decisions that keep initial costs reasonable, limit serviceability crack widths, and ensure a ductile structural response and failure path. Five small-scale, reinforced UHPC beams were experimentally tested. Longitudinal steel, transverse steel, and casting direction were varied. Results indicate that an increase in transverse steel in short-spanned reinforced UHPC beams provided additional shear capacity and increased the peak load achieved. Beams with very large longitudinal steel reinforcement ratios did not achieve yield and fully utilized the tension properties of the longitudinal steel. Casting the UHPC beams from the end or from the middle affected load-carrying capacity and ductility, but image analysis determined the fiber orientation was not significantly different. It is believed the presence of transverse and longitudinal steel reinforcement minimized the effect of different UHPC casting directions. Results support recent recommendations in the literature suggesting a 1% fiber volume fraction is sufficient within UHPC to prevent spalling and provide compressive fracture toughness under extreme loading conditions.

Keywords: fiber orientation, reinforced ultra high performance concrete beams, shear, transverse steel

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Authors: Oluyemi O. Awolusi, Abimbola M. Enitan, Sheena Kumari, Faizal Bux

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Nitrification is essential to biological processes designed to remove ammonia and/or total nitrogen. It removes the excess nitrogenous compound in wastewater which could be very toxic to the aquatic fauna or cause a serious imbalance of such aquatic ecosystem. Efficient nitrification is linked to an in-depth knowledge of the structure and dynamics of the nitrifying community structure within the wastewater treatment systems. In this study, molecular technique was employed for characterizing the microbial structure of activated sludge [ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB)] in a municipal wastewater treatment with intention of linking it to the plant efficiency. PCR-based phylogenetic analysis was also carried out for. The average operating and environmental parameters, as well as specific nitrification rate of a plant, was investigated during the study. During the investigation, the average temperature was 23±1.5oC. Other operational parameters such as mixed liquor suspended solids and chemical oxygen demand inversely correlated with ammonia removal. The dissolved oxygen level in the plant was constantly lower than the optimum (between 0.24 and 1.267 mg/l) during this study. The plant was treating wastewater with the influent ammonia concentration of 31.69 and 24.47 mg/l. The influent flow rates (ML/day) was 96.81 during the period. The dominant nitrifiers include: Nitrosomonas spp. Nitrobacter spp. and Nitrospira spp. The AOB had a correlation with nitrification efficiency and temperature. This study shows that the specific ammonia oxidizing rate and the specific nitrate formation rates can serve as a good indicator of the plant overall nitrification performance.

Keywords: Ammonia monooxygenase α-subunit gene, amoA, ammonia-oxidizing bacteria, AOB, nitrite-oxidizing bacteria, NOB, specific nitrification rate

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Authors: Intissar Farid

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Groundwater quality assessment is crucial for sustainable water use, especially in semi-arid regions like the Jeloula basin in Tunisia, where groundwater is essential for domestic and agricultural needs. The present research aims to characterize the suitability of groundwater for irrigational purposes by considering various parameters: total salt concentration as measured by Electrical Conductivity EC, relative proportions of Na⁺ as expressed by %Na and SAR, Kelly’s ratio, Permeability Index, Magnesium hazard and Residual Sodium chloride. Chemical data indicate that the percent sodium (%Na) in the study area ranged from 26.3 to 45.3%. According to the Wilcox diagram, the quality classification of irrigation water suggests that analyzed groundwaters are suitable for irrigation purposes. The SAR values vary between 2.1 and 5. Most of the groundwater samples plot in the Richards’C3S1 water class and indicate little danger from sodium content to soil and plant growth. The Kelly’s ratio of the analyzed samples ranged from 0.3 to 0.8. These values indicate that the waters are fit for agricultural purposes. Magnesium hazard (MH) values range from 27.5 to 52.6, with an average of 38.9 in the analyzed waters. Hence, the Mg²⁺ content of the groundwater from the shallow aquifer cannot cause any problem to the soil permeability. Permeability index (PI) values computed for the area ranged from 33.6 to 52.7%. The above result, therefore, suggests that most of the water samples fall within class I of the Doneen chart and can be categorized as good irrigation water. The groundwaters collected from the Jeloula shallow aquifer were found to be within the safe limits and thus suitable for irrigation purposes.

Keywords: Kelly's ratio, magnesium hazard, permeability index, residual sodium chloride

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Authors: Apichet Boonsoong

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In the Chanthaburi-Trat basalts, xenoliths are composed of essentially ultramafic xenoliths (particularly spinel lherzolite) with a few of an aggregate of feldspar. Some 19 ultramafic xenoliths were collected from 13 different locations. They range in size from 3.5 to 60mm across. Most are weathered and oxidized on the surface but fresh samples are obtained from cut surfaces. Chemical analyses were performed on carbon-coated polished thin sections using a fully automated CAMECA SX-50 electron microprobe (EMPA) in wavelength-dispersive mode. In thin section, they are seen to consist of variable amounts of olivine, clinopyroxene, orthopyroxene with minor spinel and plagioclase, and are classed as lherzolite. Modal compositions of the ultramafic nodules vary with olivine (60-75%), clinopyroxene (20-30%), orthopyroxene (0-15%), minor spinel (1-3%) and plagioclase (<1%). The essential minerals form an equigranular, medium- to coarse-grained, granoblastic texture, and all are in mutual contact indicating attainment of equilibrium. Reaction rims are common along the nodule margins and in some are also present along grain boundaries. Zoning occurs in clinopyroxene, and to a lesser extent in orthopyroxene. The homogeneity of mineral compositions in lherzolite xenoliths suggests the attainment of equilibrium. The equilibration temperatures of these xenoliths are estimated to be in the range of 973 to 1063°C. Pressure estimates are not so easily obtained because no suitable barometer exists for garnet-free lherzolites and so an indirect method was used. The general mineral assemblage of the lherzolite xenoliths and the absence of garnet indicate a pressure range of approximately 12–19kbar, which is equivalent to depths approximately of 38 to 60km.

Keywords: chanthaburi-trat basalts, spinel lherzolite, xenoliths, 973 to 1063°C, 38 to 60km

Procedia PDF Downloads 112

Authors: H. Yanar, G. Purcek, H. H. Ayar

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The ingredients of composite materials used for the production of composite brake pads play an important role in terms of safety braking performance of automobiles and trains. Therefore, the ingredients must be selected carefully and used in appropriate ratios in the matrix structure of the brake pad materials. In the present study, a non-asbestos organic composite brake pad materials containing binder resin, space fillers, solid lubricants, and friction modifier was developed, and its fillers content was optimized by adding natural rubber with different rate into the specified matrix structure in order to achieve the best combination of tribo-performance and mechanical properties. For this purpose, four compositions with different rubber content (2.5wt.%, 5.0wt.%, 7.5wt.% and 10wt.%) were prepared and then test samples with the diameter of 20 mm and length of 15 mm were produced to evaluate the friction and mechanical behaviors of the mixture. The friction and wear tests were performed using a pin-on-disc type test rig which was designed according to NF-F-11-292 French standard. All test samples were subjected to two different types of friction tests defined as periodic braking and continuous braking (also known as fade test). In this way, the coefficient of friction (CoF) of composite sample with different rubber content were determined as a function of number of braking cycle and temperature of the disc surface. The results demonstrated that addition of rubber into the matrix structure of the composite caused a significant change in the CoF. Average CoF of the composite samples increased linearly with increasing rubber content into the matrix. While the average CoF was 0.19 for the rubber-free composite, the composite sample containing 20wt.% rubber had the maximum CoF of about 0.24. Although the CoF of composite sample increased, the amount of specific wear rate decreased with increasing rubber content into the matrix. On the other hand, it was observed that the CoF decreased with increasing temperature generated in-between sample and disk depending on the increasing rubber content. While the CoF decreased to the minimum value of 0.15 at 400 °C for the rubber-free composite sample, the sample having the maximum rubber content of 10wt.% exhibited the lowest one of 0.09 at the same temperature. Addition of rubber into the matrix structure decreased the hardness and strength of the samples. It was concluded from the results that the composite matrix with 5 wt.% rubber had the best composition regarding the performance parameters such as required frictional and mechanical behavior. This composition has the average CoF of 0.21, specific wear rate of 0.024 cm³/MJ and hardness value of 63 HRX.

Keywords: brake pad composite, friction and wear, rubber, friction materials

Procedia PDF Downloads 132

Authors: Mateen A Khan, Taj Mohammad, Md. Imtaiyaz Hassan

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Alzheimer’s disease is characterized by the accumulation of the processing products of the amyloid beta peptide cleaved by amyloid precursor protein (APP). Iron increases the synthesis of amyloid beta peptides, which is why iron is present in Alzheimer's disease patients' amyloid plaques. Iron misregulation in the brain is linked to the overexpression of APP protein, which is directly related to amyloid-β aggregation in Alzheimer’s disease. The APP 5'-UTR region encodes a functional iron-responsive element (IRE) stem-loop that represents a potential target for modulating amyloid production. Targeted regulation of APP gene expression through the modulation of 5’-UTR sequence function represents a novel approach for the potential treatment of AD because altering APP translation can be used to improve both the protective brain iron balance and provide anti-amyloid efficacy. The molecular docking analysis of APP IRE RNA with eukaryotic translation initiation factors yields several models exhibiting substantial binding affinity. The finding revealed that the interaction involved a set of functionally active residues within the binding sites of eIF4F. Notably, APP IRE RNA and eIF4F interaction were stabilized by multiple hydrogen bonds with residues of APP IRE RNA and eIF4F. It was evident that APP IRE RNA exhibited a structural complementarity that tightly fit within binding pockets of eIF4F. The simulation studies further revealed the stability of the complexes formed between RNA and eIF4F, which is crucial for assessing the strength of these interactions and subsequent roles in the pathophysiology of Alzheimer’s disease. In addition, MD simulations would capture conformational changes in the IRE RNA and protein molecules during their interactions, illustrating the mechanism of interaction, conformational change, and unbinding events and how it may affect aggregation propensity and subsequent therapeutic implications. Our binding studies correlated well with the translation efficiency of APP mRNA. Overall, the outcome of this study suggests that the genomic modification and/or inhibiting the expression of amyloid protein by targeting APP IRE RNA can be a viable strategy to identify potential therapeutic targets for AD and subsequently be exploited for developing novel therapeutic approaches.

Keywords: Alzheimer's disease, Protein-RNA interaction analysis, molecular docking simulations, conformational dynamics, binding stability, binding kinetics, protein synthesis.

Procedia PDF Downloads 51