Search results for: diazonium salt reduction
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5485

Search results for: diazonium salt reduction

4315 Collaboration of UNFPA and USAID to Mobilize Domestic Government Resources for Contraceptive Procurement in Madagascar

Authors: Josiane Yaguibou, Ngoy Kishimba, Issiaka v. Coulibaly, Sabrina Pestilli, Falinirina Razanalison, Hantanirina Andremanisa

Abstract:

Background: In recent years, Madagascar has faced a significant reduction in donors’ financial resources for the purchase of contraceptive products to meet the family planning needs of the population. In order to ensure the sustainability of the family planning program in the current context, UNFPA Madagascar engaged in a series of initiatives with the ultimate scope of identifying sustainable financing mechanisms for the program. Program intervention: UNFPA Madagascar established a strict collaboration with USAID to engage in a series of joint advocacy and resource mobilization activities with the government. The following initiatives were conducted: (i) Organization of a high-level Round Table to engage the government; (ii) Support to the government in renewing the FP2030 Commitments; (iii) Signature of the Country Compact 2022-2024; (iv) Allocation of government funds in 2022 and 2023 of over 829,222 USD; (v) Obtaining a Matching Fund of 1.5 million USD from UNFPA to encourage the government to allocate resources for the purchase of contraceptive products. Program Implications: The collaboration and the joint advocacy made it possible to (i) have budgetary allocations from the government to purchase products in 2022 and 2023 with a significant reduction in financing gaps; (ii) to convince the government to seek additional financing from partners such as the World Bank which granted more than 8 million USD for the purchase of products; (iii) reduce stock shortages from more than 30% to 15%.

Keywords: UNFPA, USAID, collaboration, contraceptives

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4314 Effect of Jatropha curcas Leaf Extract on Castor Oil Induced Diarrhea in Albino Rats

Authors: Fatima U. Maigari, Musa Halilu, M. Maryam Umar, Rabiu Zainab

Abstract:

Plants as therapeutic agents are used as drug in many parts of the world. Medicinal plants are mostly used in developing countries due to culture acceptability, belief or due to lack of easy access to primary health care services. Jatropha curcas is a plant from the Euphorbiaceae family which is widely used in Northern Nigeria as an anti-diarrheal agent. This study was conducted to determine the anti-diarrheal effect of the leaf extract on castor oil induced diarrhea in albino rats. The leaves of J. curcas were collected from Balanga Local government in Gombe State, north-eastern Nigeria; due to its bioavailability. The leaves were air-dried at room temperature and ground to powder. Phytochemical screening was done and different concentrations of the extract was prepared and administered to the different categories of experimental animals. From the results, aqueous leaf extract of Jatropha curcas at doses of 200mg/Kg and 400mg/Kg was found to reduce the mean stool score as compared to control rats, however, maximum reduction was achieved with the standard drug of Loperamide (5mg/Kg). Treatment of diarrhea with 200mg/Kg of the extract did not produce any significant decrease in stool fluid content but was found to be significant in those rats that were treated with 400mg/Kg of the extract at 2hours (0.05±0.02) and 4hours (0.01±0.01). A significant reduction of diarrhea in the experimental animals signifies it to possess some anti-diarrheal activity.

Keywords: anti-diarrhea, diarrhea, Jatropha curcas, loperamide

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4313 Incentive Policies to Promote Green Infrastructure in Urban Jordan

Authors: Zayed Freah Zeadat

Abstract:

The wellbeing of urban dwellers is strongly associated with the quality and quantity of green infrastructure. Nevertheless, urban green infrastructure is still lagging in many Arab cities, and Jordan is no exception. The capital city of Jordan, Amman, is becoming more urban dense with limited green spaces. The unplanned urban growth in Amman has caused several environmental problems such as urban heat islands, air pollution, and lack of green spaces. This study aims to investigate the most suitable drivers to leverage the implementation of urban green infrastructure in Jordan through qualitative and quantitative analysis. The qualitative research includes an extensive literature review to discuss the most common drivers used internationally to promote urban green infrastructure implementation in the literature. The quantitative study employs a questionnaire survey to rank the suitability of each driver. Consultants, contractors, and policymakers were invited to fill the research questionnaire according to their judgments and opinions. Relative Importance Index has been used to calculate the weighted average of all drivers and the Kruskal-Wallis test to check the degree of agreement among groups. This study finds that research participants agreed that indirect financial incentives (i.e., tax reductions, reduction in stormwater utility fee, reduction of interest rate, density bonus, etc.) are the most effective incentive policy whilst granting sustainability certificate policy is the least effective driver to ensure widespread of UGI is elements in Jordan.

Keywords: urban green infrastructure, relative importance index, sustainable urban development, urban Jordan

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4312 Antihyperglycemic Effect of Aqueous Extract of Foeniculum vulgare Miller in Diabetic Mice

Authors: Singh Baljinder, Sharma Navneet

Abstract:

Foeniculum vulgare Miller is a biennial medicinal and aromatic plant belonging to the family Apiaceae (Umbelliferaceae). It is a hardy, perennial–umbelliferous herb with yellow flowers and feathery leaves. The aim is to study the control of blood glucose in alloxan induced diabetic mice.Method used for extraction was continuous hot percolation method in which Soxhlet apparatus was used.95%ethanol was used as solvent. Male albino mice weighing about 20-25 g obtained from Guru Angad Dev University of Veterinary Science, Ludhiana were used for the study. Diabetes was induced by a single i.p. injection of 125 mg/kg of alloxan monohydrate in sterile saline (11). After 48 h, animals with serum glucose level above 200 mg/dl (diabetic) were selected for the study. Blood samples from mice were collected by retro-orbital puncture (ROP) technique. Serum glucose levels were determined by glucose oxidase and peroxidase method. Single administration (single dose) of aqueous extract of fennel (25, 50, and 100 mg/kg, p.o.) in diabetic Swiss albino mice, showed reduction in serum glucose level after 45 min. Maximum reduction in serum glucose level was seen at doses of 100 mg/kg. Aqueous extract of fennel in all doses except 25 mg/kg did not cause any significant decrease in blood glucose. It may be said that the aqueous extract of fennel decreased the serum glucose level and improved glucose tolerance owing to the presence of aldehyde moiety. The aqueous extract of fennel has antihyperglycemic activity as it lowers serum glucose level in diabetic mice.

Keywords: Foeniculum vulgare Miller, antihyperglycemic, diabetic mice, Umbelliferaceae

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4311 Hybrid Advanced Oxidative Pretreatment of Complex Industrial Effluent for Biodegradability Enhancement

Authors: K. Paradkar, S. N. Mudliar, A. Sharma, A. B. Pandit, R. A. Pandey

Abstract:

The study explores the hybrid combination of Hydrodynamic Cavitation (HC) and Subcritical Wet Air Oxidation-based pretreatment of complex industrial effluent to enhance the biodegradability selectively (without major COD destruction) to facilitate subsequent enhanced downstream processing via anaerobic or aerobic biological treatment. Advanced oxidation based techniques can be less efficient as standalone options and a hybrid approach by combining Hydrodynamic Cavitation (HC), and Wet Air Oxidation (WAO) can lead to a synergistic effect since both the options are based on common free radical mechanism. The HC can be used for initial turbulence and generation of hotspots which can begin the free radical attack and this agitating mixture then can be subjected to less intense WAO since initial heat (to raise the activation energy) can be taken care by HC alone. Lab-scale venturi-based hydrodynamic cavitation and wet air oxidation reactor with biomethanated distillery wastewater (BMDWW) as a model effluent was examined for establishing the proof-of-concept. The results indicated that for a desirable biodegradability index (BOD: COD - BI) enhancement (up to 0.4), the Cavitation (standalone) pretreatment condition was: 5 bar and 88 min reaction time with a COD reduction of 36 % and BI enhancement of up to 0.27 (initial BI - 0.17). The optimum WAO condition (standalone) was: 150oC, 6 bar and 30 minutes with 31% COD reduction and 0.33 BI. The hybrid pretreatment (combined Cavitation + WAO) worked out to be 23.18 min HC (at 5 bar) followed by 30 min WAO at 150oC, 6 bar, at which around 50% COD was retained yielding a BI of 0.55. FTIR & NMR analysis of pretreated effluent indicated dissociation and/or reorientation of complex organic compounds in untreated effluent to simpler organic compounds post-pretreatment.

Keywords: hybrid, hydrodynamic cavitation, wet air oxidation, biodegradability index

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4310 Structural Performance Evaluation of Concrete Beams Reinforced with Recycled and Virgin Plastic Fibres

Authors: Vighnesh Daas, David B. Tann, Mahmood Datoo

Abstract:

The incorporation of recycled plastic fibres in concrete as reinforcement is a potential sustainable alternative for replacement of ordinary steel bars. It provides a scope for waste reduction and re-use of plastics in the construction industry on a large scale. Structural use of fibre reinforced concrete is limited to short span members and low reliability classes. In this study, recycled carpet fibres made of 95% polypropylene with length of 45mm were used for experimental investigations. The performance of recycled polypropylene fibres under structural loading has been compared with commercially available virgin fibres at low volume fractions of less than 1%. A series of 100 mm cubes and 125x200x2000 mm beams were used to conduct strength tests in bending and compression to measure the influence of type and volume of fibres on the structural behaviour of fibre reinforced concrete beams. The workability of the concrete mix decreased as a function of fibre content and resulted in a modification of the mix design. The beams failed in a pseudo-ductile manner with an enhanced bending capacity. The specimens showed significant improvement in the post-cracking behaviour and load carrying ability as compared to conventional reinforced concrete members. This was associated to the binding properties of the fibres in the concrete matrix. With the inclusion of fibres at low volumes of 0-0.5%, there was reduction in crack sizes and deflection. This study indicates that the inclusion of recycled polypropylene fibres at low volumes augments the structural behaviour of concrete as compared to conventional reinforced concrete as well as virgin fibre reinforced concrete.

Keywords: fibre reinforced concrete, polypropylene, recycled, strength

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4309 Cataract Surgery and Sustainability: Comparative Study of Single-Use Versus Reusable Cassettes in Phacoemulsification

Authors: Oscar Kallay

Abstract:

Objective: This study compares the sustainability, financial implications, and surgical efficiency of two phacoemulsification cassette systems for cataract surgery: a machine with single-use cassettes and another with daily, reusable ones. Methods: The observational study involves retrospective cataract surgery data collection at the Centre Médical de l'Alliance, Braine-L’alleud, Belgium, a tertiary eye care center. Information on cassette weight, quantities, and transport volume was obtained from routine procedures and purchasing records. The costs for each machine were calculated by reviewing the invoices received from the accounting department. Results: We found significant differences across comparisons. The reusable cassette machine, when compared to the single-use machine, used 306.7 kg less plastic (75.3% reduction), required 2,494 cubic meters less storage per 1000 surgeries (67.7% decrease), and cost €54.16 less per 10 procedures (16.9% reduction). The machine with daily reusable cassettes also exhibited a 7-minute priming time advantage for 10 procedures, reducing downtime between cases. Conclusions: Our findings underscore the benefits of adopting reusable cassette systems: reduced plastic consumption, storage volume, and priming time, as well as enhanced efficiency and cost savings. Healthcare professionals and institutions are encouraged to embrace environmentally conscious initiatives. The use of reusable cassette systems for cataract surgeries offers a pathway to sustainable practices.

Keywords: cataract, epidemiolog, surgery treatment, lens and zonules, public health

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4308 Pellegrini-Stieda Syndrome: A Physical Medicine and Rehabilitation Approach

Authors: Pedro Ferraz-Gameiro

Abstract:

Introduction: The Pellegrini-Stieda lesion is the result of post-traumatic calcification and/or ossification on the medial collateral ligament (MCL) of the knee. When this calcification is accompanied by gonalgia and limitation of knee flexion, it is called Pellegrini-Stieda syndrome. The pathogenesis is probably the calcification of a post-traumatic hematoma at least three weeks after the initial trauma or secondary to repetitive microtrauma. On anteroposterior radiographs, a Pellegrini-Stieda lesion is a linear vertical ossification or calcification of the proximal portion of the MCL and usually near the medial femoral condyle. Patients with Pellegrini-Stieda syndrome present knee pain associated with loss of range of motion. The treatment is usually conservative with analgesic and anti-inflammatory drugs, either systemic or intra-articular. Physical medicine and rehabilitation techniques associated with shock wave therapy can be a way of reduction of pain/inflammation. Patients who maintain instability with significant limitation of knee mobility may require surgical excision. Methods: Research was done using PubMed central using the terms Pellegrini-Stieda syndrome. Discussion/conclusion: Medical treatment is the rule, with initial rest, anti-inflammatory, and physiotherapy. If left untreated, this ossification can potentially form a significant bone mass, which can compromise the range of motion of the knee. Physical medicine and rehabilitation techniques associated with shock wave therapy are a way of reduction of pain/inflammation.

Keywords: knee, Pellegrini-Stieda syndrome, rehabilitation, shock waves therapy

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4307 Numerical Investigation of Material Behavior During Non-Equal Channel Multi Angular Extrusion

Authors: Mohamed S. El-Asfoury, Ahmed Abdel-Moneim, Mohamed N. A. Nasr

Abstract:

The current study uses finite element modeling to investigate and analyze a modified form of the from the conventional equal channel multi-angular pressing (ECMAP), using non-equal channels, on the workpiece material plastic deformation. The modified process non-equal channel multi-angular extrusion (NECMAE) is modeled using two-dimensional plane strain finite element model built using the commercial software ABAQUS. The workpiece material used is pure aluminum. The model was first validated by comparing its results to analytical solutions for single-pass equal channel angular extrusion (ECAP), as well as previously published data. After that, the model was used to examine the effects of different % of reductions of the area (for the second stage) on material plastic deformation, corner gap, and required the load. Three levels of reduction in the area were modeled; 10%, 30%, and 50%, and compared to single-pass and double-pass ECAP. Cases with a higher reduction in the area were found to have smaller corner gaps, higher and much uniform plastic deformation, as well as higher required loads. The current results are mainly attributed to the back pressure effects exerted by the second stage, as well as strain hardening effects experienced during the first stage.

Keywords: non-equal channel angular extrusion, multi-pass, sever plastic deformation, back pressure, Finite Element Modelling (FEM)

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4306 Utilization Reactive Dilutes to Improve the Properties of Epoxy Resin as Anticorrosion Coating

Authors: El-Sayed Negim, Ainakulova D. T., Puteri S. M., Khaldun M. Azzam, Bekbayeva L. K., Arpit Goyal, Ganjian E.

Abstract:

Anticorrosion coatings protect metal surfaces from environmental factors including moisture, oxygen, and gases that caused corrosion to the metal. Various types of anticorrosion coatings are available, with different properties and application methods. Many researchers have been developing methods to prevent corrosion, and epoxy polymers are one of the wide methods due to their excellent adhesion, chemical resistance, and durability. In this study, synthesis reactive dilute based on glycidyl methacrylate (GMA) with each of 2-ethylhexyl acrylate (2-EHA) and butyl acrylate (BuA) to improve the performance of epoxy resin and anticorrosion coating. The copolymers were synthesized with composition ratio (5/5) by bulk polymerization technique using benzoyl peroxide as a catalyst and temperature at 85 oC for 2 hours and at 90 oC for 30 minutes to complete the polymerization process. The obtained copolymers were characterized by FTIR, viscosity and thixotropic index. The effect of copolymers as reactive dilute on the physical and mechanical properties of epoxy resin was investigated. Metal plates coated by the modified epoxy resins with different contents of copolymers were tested using alkali and salt test methods, and the copolymer based on GMA and BUA showed the best protection efficiency due to the barrier effect of the polymer layer.

Keywords: epoxy, coating, dilute, corrosion, reactive

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4305 Sustainable Pavements with Reflective and Photoluminescent Properties

Authors: A.H. Martínez, T. López-Montero, R. Miró, R. Puig, R. Villar

Abstract:

An alternative to mitigate the heat island effect is to pave streets and sidewalks with pavements that reflect incident solar energy, keeping their surface temperature lower than conventional pavements. The “Heat island mitigation to prevent global warming by designing sustainable pavements with reflective and photoluminescent properties (RELUM) Project” has been carried out with this intention in mind. Its objective has been to develop bituminous mixtures for urban pavements that help in the fight against global warming and climate change, while improving the quality of life of citizens. The technology employed has focused on the use of reflective pavements, using bituminous mixes made with synthetic bitumens and light pigments that provide high solar reflectance. In addition to this advantage, the light surface colour achieved with these mixes can improve visibility, especially at night. In parallel and following the latter approach, an appropriate type of treatment has also been developed on bituminous mixtures to make them capable of illuminating at night, giving rise to photoluminescent applications, which can reduce energy consumption and increase road safety due to improved night-time visibility. The work carried out consisted of designing different bituminous mixtures in which the nature of the aggregate was varied (porphyry, granite and limestone) and also the colour of the mixture, which was lightened by adding pigments (titanium dioxide and iron oxide). The reflectance of each of these mixtures was measured, as well as the temperatures recorded throughout the day, at different times of the year. The results obtained make it possible to propose bituminous mixtures whose characteristics can contribute to the reduction of urban heat islands. Among the most outstanding results is the mixture made with synthetic bitumen, white limestone aggregate and a small percentage of titanium dioxide, which would be the most suitable for urban surfaces without road traffic, given its high reflectance and the greater temperature reduction it offers. With this solution, a surface temperature reduction of 9.7°C is achieved at the beginning of the night in the summer season with the highest radiation. As for luminescent pavements, paints with different contents of strontium aluminate and glass microspheres have been applied to asphalt mixtures, and the luminance of all the applications designed has been measured by exciting them with electric bulbs that simulate the effect of sunlight. The results obtained at this stage confirm the ability of all the designed dosages to emit light for a certain time, varying according to the proportions used. Not only the effect of the strontium aluminate and microsphere content has been observed, but also the influence of the colour of the base on which the paint is applied; the lighter the base, the higher the luminance. Ongoing studies are focusing on the evaluation of the durability of the designed solutions in order to determine their lifetime.

Keywords: heat island, luminescent paints, reflective pavement, temperature reduction

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4304 5-HT2CR Deficiency Causes Affective Disorders by Impairing E/I Balance through Augmenting Hippocampal nNOS-CAPON Coupling

Authors: Hu-Jiang Shi, Li-Juan Zhu

Abstract:

The implication of 5-hydroxytryptamine 2C receptor (5-HT2CR) in affective behaviors is a topic of debate, and the underlying mechanisms remain largely unclear. Here, we elucidate that the interaction between hippocampal neuronal nitric oxide synthase (nNOS) and carboxy-terminal PDZ ligand of nNOS (CAPON) contributes to the disruption of hippocampal excitation-inhibition (E/I) balance, which is responsible for the anxiety- and depressive-like behaviors caused by chronic stress-related 5-HT2CR signaling deficiency. In detail, activation or inhibition of 5-HT2CR by CP809101 or SB242084 modulates nNOS-CAPON interaction by influencing intracellular Ca²⁺ release. Notably, the dissociation of nNOS-CAPON abolishes SB242084-induced anxiety- and depressive-like behaviors, as well as the reduction in extracellular signal-regulated kinase (ERK)/cAMP-response element binding protein (CREB)/synapsin signaling and SNARE complex assembly. Furthermore, nNOS-CAPON blockers restore the impairments caused by SB242084, including the reduction in SNARE assembly-mediated γ-aminobutyric acid (GABA) vesicle release and a consequent shift of the E/I balance toward excitation in CA3 pyramidal neurons. Conclusively, our findings disclose the regulatory role of 5-HT2CR in anxiety- and depressive-like behaviors and highlight the hippocampal nNOS-CAPON coupling-triggered E/I imbalance as a pivotal cellular event underpinning the behavioral consequences of 5-HT2CR inhibition.

Keywords: 5-HT2CR, anxiety, depression, nNOS-CAPON coupling, excitation-inhibition balance, neurotransmitter release

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4303 Novel Anticorrosion Epoxy Reinforced Graphitic Nanocomposite as a Durable Surface

Authors: Shimaa A. Higazy, Mohamed S. Selim, Olfat E. El-Azabawy, Abeer A. Hassan

Abstract:

We designed novel epoxy/graphitic carbon nitride (g-C₃N₄) nanocomposite materials as suitable surface coatings. g-C₃N₄ nanosheets were facilely prepared and dispersed in the epoxy resin via solution casting. This research focuses on the mechanical and anticorrosion properties of g-C₃N₄ nanofiller reinforced epoxy nanocomposites. The structures, sizes, and morphologies of designed polymeric nanocomposites and nanofillers were elucidated using various techniques such as FT-IR, NMR, FE-TEM, FE-SEM. The developed nanocomposite was applied as a surface coating by air-assisted spray method. The structure-property relationship was studied for different concentrations of nanofiller in the epoxy matrix. The anticorrosive properties were studied via electrochemical experiments, including potentiodynamic polarization, electrochemical impedance, and open-circuit potential analyses, as well as salt spray test. Mechanical durability was assessed by various methods, such as impact, T-bending, and crosscut tests. Surface heterogeneity, elasticity, and corrosion-resistance features are among the merits of developed composite. The highest improvement was achieved with well dispersion of g-C₃N₄ sheets fillers. This fascinating epoxy nanostructured coating provides a promising anticorrosive coatings for a sustainable future environment.

Keywords: epoxy, nanocomposite, surface coating, anticorrosive properties, mechanical durability

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4302 Numerical Study of Leisure Home Chassis under Various Loads by Using Finite Element Analysis

Authors: Asem Alhnity, Nicholas Pickett

Abstract:

The leisure home industry is experiencing an increase in sales due to the rise in popularity of staycations. However, there is also a demand for improvements in thermal and structural behaviour from customers. Existing standards and codes of practice outline the requirements for leisure home design. However, there is a lack of expertise in applying Finite Element Analysis (FEA) to complex structures in this industry. As a result, manufacturers rely on standardized design approaches, which often lead to excessively engineered or inadequately designed products. This study aims to address this issue by investigating the impact of the habitation structure on chassis performance in leisure homes. The aim of this research is to comprehensively analyse the impact of the habitation structure on chassis performance in leisure homes. By employing FEA on the entire unit, including both the habitation structure and the chassis, this study seeks to develop a novel framework for designing and analysing leisure homes. The objectives include material reduction, enhancing structural stability, resolving existing design issues, and developing innovative modular and wooden chassis designs. The methodology used in this research is quantitative in nature. The study utilizes FEA to analyse the performance of leisure home chassis under various loads. The analysis procedures involve running the FEA simulations on the numerical model of the leisure home chassis. Different load scenarios are applied to assess the stress and deflection performance of the chassis under various conditions. FEA is a numerical method that allows for accurate analysis of complex systems. The research utilizes flexible mesh sizing to calculate small deflections around doors and windows, with large meshes used for macro deflections. This approach aims to minimize run-time while providing meaningful stresses and deflections. Moreover, it aims to investigate the limitations and drawbacks of the popular approach of applying FEA only to the chassis and replacing the habitation structure with a distributed load. The findings of this study indicate that the popular approach of applying FEA only to the chassis and replacing the habitation structure with a distributed load overlooks the strengthening generated from the habitation structure. By employing FEA on the entire unit, it is possible to optimize stress and deflection performance while achieving material reduction and enhanced structural stability. The study also introduces innovative modular and wooden chassis designs, which show promising weight reduction compared to the existing heavily fabricated lattice chassis. In conclusion, this research provides valuable insights into the impact of the habitation structure on chassis performance in leisure homes. By employing FEA on the entire unit, the study demonstrates the importance of considering the strengthening generated from the habitation structure in chassis design. The research findings contribute to advancements in material reduction, structural stability, and overall performance optimization. The novel framework developed in this study promotes sustainability, cost-efficiency, and innovation in leisure home design.

Keywords: static homes, caravans, motor homes, holiday homes, finite element analysis (FEA)

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4301 The Efficacy of Vestibular Rehabilitation Therapy for Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Authors: Ammar Aljabri, Alhussain Halawani, Alaa Ashqar, Omar Alageely

Abstract:

Objective: mild Traumatic Brain Injury (mTBI) or concussion is a common yet undermanaged and underreported condition. This systematic review and meta-analysis aim to determine the efficacy of VRT as a treatment option for mTBI. Method: This review and meta-analysis was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and included RCTs and pre-VRT/post-VRT retrospective chart reviews. Records meeting the inclusion criteria were extracted from the following databases: Medline, Embase, and Cochrane Register of Controlled Trials (CENTRAL). Results: Eight articles met the inclusion criteria, and six RCTs were included in the meta-analysis. VRT demonstrated significant improvement in decreasing perceived dizziness at the end of the intervention program, as shown by DHI scores (SMD= -0.33, 95% CI -0.62 to -0.03, p=0.03, I2= 0%). However, no significant reduction in DHI was evident after two months of follow-up (SMD= 0.15, 95% CI -0.23 to 0.52, p=0.44, I2=0%). Quantitative analysis also depicts significant reduction in both VOMS (SMD=-0.40, 95% CI -0.60 to -0.20, p<0.0001, I2=0%) and PCSS (SMD= -0.39, 95% CI -0.71 to -0.07, p=0.02, I2=0%) following the intervention. Lastly, there was no significant difference between intervention groups on BESS scores (SMD= -31, 95% CI -0.71 to 0.10, p=0.14, I2=0%) and return to sport/function (95% CI 0.32 to 30.80, p=0.32, I2=82%). Conclusions: Current evidence on the efficacy of VRT for mTBI is limited. This review and analysis provide evidence that supports the role of VRT in improving perceived symptoms following concussion. There is still a need for high-quality trials evaluating the benefit of VRT using a standardized approach.

Keywords: concussion, traumatic brain injury, vestibular rehabilitation, neurorehabilitation

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4300 Preparation and Characterization of Bioplastic from Sorghum Husks

Authors: Hannatu Abubakar Sani, Abubakar Umar Birnin Yauri, Aliyu Muhammad, Mujahid Salau, Aminu Musa, Hadiza Adamu Kwazo

Abstract:

The increase in the global population and advances in technology have made plastic materials to have wide applications in every aspect of life. However, the non-biodegradability of these petrochemical-based materials and their increasing accumulation in the environment has been a threat to the planet and has been a source of environmental concerns and hence, the driving force in the search for ‘green’ alternatives for which agricultural waste remains the front liner. Sorghum husk, an agricultural waste with potentials as a raw material in the production of bioplastic, was used in this research to prepare bioplastic using sulphuric acid-catalyzed acetylation process. The prepared bioplastic was characterized by X-ray diffraction and Fourier transform infrared spectroscopy (FTIR), and the structure of the prepared bioplastic was confirmed. The Fourier transform infrared spectroscopy (FTIR) spectra of the product displayed the presence of OH, C-H, C=O, and C-O absorption peaks. The bioplastic obtained is biodegradable and is affected by acid, salt, and alkali to a lesser extent. Other tests like solubility and swelling studies were carried out to ensure the commercial properties of these bioplastic materials. Therefore, this revealed that new bioplastics with better environmental and sustainable properties could be produced from agricultural waste, which may have applications in many industries.

Keywords: agricultural waste, bioplastic, characterization, Sorghum Husk

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4299 Potential of Ozonation and Phytoremediation to Reduce Hydrocarbon Levels Remaining after the Pilot Scale Microbial Based Bioremediation (Land-Farming) of a Heavily Polluted Soil

Authors: Hakima Althalb

Abstract:

Petroleum contamination of sandy soils is a severe environmental problem in Libya, but relatively little work has been carried out to optimize the bioremediation of such heavily contaminated soil, particularly at a pilot scale. The purpose of this research was to determine the potential for the microbial-based bioremediation of hydrocarbon-contaminated soil obtained from an oil refinery in Libya and to assess the potential of both ozonation and phytoremediation (both applied after initial bioremediation) to reduce residual hydrocarbon levels. Plots containing 500 kg soil (triplicates) (contaminated soil diluted with clean soil 50% volume) were set up, (designated as Land Treatment Units; LTUs) containing five different nutrient levels and mixtures (Urea + NPK (nitrogen; phosphor; potassium) mixtures) to obtain C:N:P ratios 100:10:1, and monitored for 90 days. Hydrocarbon levels, microbial numbers, and toxicity (EC50 using luminescent microbial based tests) were assessed. Hydrocarbon levels in non-diluted and diluted soil ranged from 20 733-22 366 mg/kg and from 16 000-17 000 mg/kg respectively. Although all the land treatment units revealed a significant hydrocarbon reduction over time, the highest reduction in hydrocarbon levels obtained was around 60%. For example, 63% hydrocarbon removal was observed using a mixture of urea and NPK with a C:N:P ratio of 100:10:1). Soil toxicity (as assessed using luminescence based toxicity assays) reduced in line with the reduction in total petroleum hydrocarbons observed. However, as relatively high residual TPH (total petroleum hydrocarbon) levels (ranging from 6033-14166mg/kg) were still present after initial bioremediation two ‘post-treatments’ (phytoremediation and ozonation) were attempted to remove residual hydrocarbons remaining. Five locally grown (agriculturally important) plant species were tested. The germination of all plants examined was strongly inhibited (80-100%) and seedlings failed to grow well in the contaminated soil, indicating that the previously bioremediated soils were still toxic to the plants. Subsequent ozonation followed by another bioremediation of soil was more successful than phytoremediation. But even the most promising successful treatment in this study (ozonation for 6 hours at 25ppm followed by bioremediation) still only removed approximately 31% of the residual hydrocarbons. Overall, this work showed that the bioremediation of such highly contaminated soils is difficult and that a combination of treatments would be required to achieve successful remediation. Even after initial dilution and bioremediation the soils remained toxic to plant growth and were therefore not suitable for phytoremediation.

Keywords: bioremediation, petroleum hydrocarbons, ozone, phytoremediation

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4298 Robust Medical Image Watermarking based on Contourlet and Extraction Using ICA

Authors: S. Saju, G. Thirugnanam

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In this paper, a medical image watermarking algorithm based on contourlet is proposed. Medical image watermarking is a special subcategory of image watermarking in the sense that images have special requirements. Watermarked medical images should not differ perceptually from their original counterparts because clinical reading of images must not be affected. Watermarking techniques based on wavelet transform are reported in many literatures but robustness and security using contourlet are better when compared to wavelet transform. The main challenge in exploring geometry in images comes from the discrete nature of the data. In this paper, original image is decomposed to two level using contourlet and the watermark is embedded in the resultant sub-bands. Sub-band selection is based on the value of Peak Signal to Noise Ratio (PSNR) that is calculated between watermarked and original image. To extract the watermark, Kernel ICA is used and it has a novel characteristic is that it does not require the transformation process to extract the watermark. Simulation results show that proposed scheme is robust against attacks such as Salt and Pepper noise, Median filtering and rotation. The performance measures like PSNR and Similarity measure are evaluated and compared with Discrete Wavelet Transform (DWT) to prove the robustness of the scheme. Simulations are carried out using Matlab Software.

Keywords: digital watermarking, independent component analysis, wavelet transform, contourlet

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4297 Investigating Nanocrystalline CaF2:Tm for Carbon Beam and Gamma Radiation Dosimetry

Authors: Kanika Sharma, Shaila Bahl, Birendra Singh, Pratik Kumar, S. P. Lochab, A. Pandey

Abstract:

In the present investigation, initially nano-particles of CaF2 were prepared by the chemical co-precipitation method and later the prepared salt was activated by thulium (0.1 mol%) using the combustion technique. The final product was characterized and confirmed by X-Ray diffraction (XRD) and transmission electron microscopy (TEM). Further, the thermoluminescence (TL) properties of the nanophosphor were studied by irradiating it with 1.25 MeV of gamma radiation and 65 MeV of carbon (C6+) ion beam. For gamma rays, two prominent TL peaks were observed with a low temperature peak at around 1070C and a high temperature peak at around 1570C. Furthermore, the nanophosphor maintained a linear TL response for the entire range of studied doses i.e. 10 Gy to 2000 Gy for both the temperature peaks. Moreover, when the nanophosphor was irradiated with 65 MeV of C6+ ion beam the shape and structure of the glow curves remained spectacularly similar and the nanophosphor displayed a linear TL response for the full range of studied fluences i.e. 5*1010 ions/cm2 to 1 *1012 ions/ cm2. Finally, various tests like reproducibility test and batch homogeneity were also carried out to define the final product. Thus, co-precipitation method followed by combustion technique was successful in effectively producing dosimetric grade CaF2:Tm for dosimetry of gamma as well as carbon (C6+) beam.

Keywords: gamma radiation, ion beam, nanocrystalline, radiation dosimetry

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4296 Wear Resistance and Mechanical Performance of Ultra-High Molecular Weight Polyethylene Influenced by Temperature Change

Authors: Juan Carlos Baena, Zhongxiao Peng

Abstract:

Ultra-high molecular weight polyethylene (UHMWPE) is extensively used in industrial and biomedical fields. The slippery nature of UHMWPE makes this material suitable for surface bearing applications, however, the operational conditions limit the lubrication efficiency, inducing boundary and mixed lubrication in the tribological system. The lack of lubrication in a tribological system intensifies friction, contact stress and consequently, operating temperature. With temperature increase, the material’s mechanical properties are affected, and the lifespan of the component is reduced. The understanding of how mechanical properties and wear performance of UHMWPE change when the temperature is increased has not been clearly identified. The understanding of the wear and mechanical performance of UHMWPE at different temperature is important to predict and further improve the lifespan of these components. This study evaluates the effects of temperature variation in a range of 20 °C to 60 °C on the hardness and the wear resistance of UHMWPE. A reduction of the hardness and wear resistance was observed with the increase in temperature. The variation of the wear rate increased 94.8% when the temperature changed from 20 °C to 50 °C. Although hardness is regarded to be an indicator of the material wear resistance, this study found that wear resistance decreased more rapidly than hardness with the temperature increase, evidencing a low material stability of this component in a short temperature interval. The reduction of the hardness was reflected by the plastic deformation and abrasion intensity, resulting in a significant wear rate increase.

Keywords: hardness, surface bearing, tribological system, UHMWPE, wear

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4295 Comparison of the Factor of Safety and Strength Reduction Factor Values from Slope Stability Analysis of a Large Open Pit

Authors: James Killian, Sarah Cox

Abstract:

The use of stability criteria within geotechnical engineering is the way the results of analyses are conveyed, and sensitivities and risk assessments are performed. Historically, the primary stability criteria for slope design has been the Factor of Safety (FOS) coming from a limit calculation. Increasingly, the value derived from Strength Reduction Factor (SRF) analysis is being used as the criteria for stability analysis. The purpose of this work was to study in detail the relationship between SRF values produced from a numerical modeling technique and the traditional FOS values produced from Limit Equilibrium (LEM) analyses. This study utilized a model of a 3000-foot-high slope with a 45-degree slope angle, assuming a perfectly plastic mohr-coulomb constitutive model with high cohesion and friction angle values typical of a large hard rock mine slope. A number of variables affecting the values of the SRF in a numerical analysis were tested, including zone size, in-situ stress, tensile strength, and dilation angle. This paper demonstrates that in most cases, SRF values are lower than the corresponding LEM FOS values. Modeled zone size has the greatest effect on the estimated SRF value, which can vary as much as 15% to the downside compared to FOS. For consistency when using SRF as a stability criteria, the authors suggest that numerical model zone sizes should not be constructed to be smaller than about 1% of the overall problem slope height and shouldn’t be greater than 2%. Future work could include investigations of the effect of anisotropic strength assumptions or advanced constitutive models.

Keywords: FOS, SRF, LEM, comparison

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4294 Effect of Natural Molecular Crowding on the Structure and Stability of DNA Duplex

Authors: Chaudhari S. G., Saxena, S.

Abstract:

We systematically and quantitatively investigated the effect of glucose as a model of natural molecular crowding agent on the structure and thermodynamics of Watson-Crick base paired three duplexes (named as D1, D2 and D3) of different base compositions and lengths. Structural analyses demonstrated that duplexes (D1 and D2) folded into B-form with different cations in the absence and presence of glucose while duplex (D3) folded into mixed A and B-form. Moreover, we demonstrated that the duplex was more stable in the absence of glucose, and marginally destabilized in its presence because glucose act as a weak structure breaker on the tetrahedral network of water. In the absence of glucose, the values of ΔG°25 for duplex (D1) were -13.56, -13.76, -12.46, and -12.36 kcal/mol, for duplex (D2) were -13.64, -12.93, -12.86, and -12.30 kcal/mol, for duplex (D3) were -10.05, -11.76, -9.91, -9.70 kcal/mol in the presence of Na+, K+, Na+ + Mg++ and K+ + Mg++ respectively. At high concentration of glucose (1:10000), there was increase in ΔG°25 for duplex (D1) -12.47, -12.37, -11.96, -11.55 kcal/mol, for duplex (D2) -12.37, -11.47, -11.98, -11.01 kcal/mol and for duplex (D3) -8.47, -9.17, -9.16, -8.66 kcal/mol. Our results provide the information that structure and stability of DNA duplex depends on the structure of molecular crowding agent present in its close vicinity. In this study, I have taken the hydration of simple sugar as an essential model for understanding interactions between hydrophilic groups and interfacial water molecules and its effect on hydrogen bonded DNA duplexes. On the basis of these relatively simple building blocks I hope to gain some insights for understanding more generally the properties of sugar–water–salt systems with DNA duplexes.

Keywords: natural molecular crowding, DNA Duplex, structure of DNA, bioengineering and life sciences

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4293 Model Evaluation of Action Potential Block in Whole-Animal Nerves Induced by Ultrashort, High-Intensity Electric Pulses

Authors: Jiahui Song

Abstract:

There have been decades of research into the action potential block in nerves. To our best knowledge electrical voltages can reversibly block the conduction of action potentials across whole animal nerves. Blocking biological electrical signaling pathways can have a variety of applications in muscular and sensory incapacitation and clinical research, including urethral pressure reduction and relieving chronic pain relief from a peripheral nerve injury. The cessation ability has been used in muscle activation and fatigue reduction. Ultrashort, high-intensity electric pulses modulate the membrane conductivity to block nerve conduction through the electroporation process. Nanopore formation on the membrane surface would increase the local membrane conductivity and effectively "short-out" the trans-membrane potential of a nerve that inhibits action potential propagation. This block would be similar in concept to stopping the propagation of an air-pressure wave down a "leaky" pipe. This research focuses on a distributed electrical model with an additional time-dependent membrane conductance to calculate the poration induced by the ultrashort, high-intensity electric pulses. The changes in membrane conductivity are used to predict changes in action potential transmission. A "strength-duration (SD)" curve is generated for action potential blockage and would be used as a design guide for benchmarking safety thresholds or setting the pulse voltage and/or durations necessary for neuro-muscular incapacitation.

Keywords: action potential, ultrashort, high-intensity, nerve, strength-duration

Procedia PDF Downloads 18
4292 Cost Valuation Method for Development Concurrent, Phase Appropriate Requirement Valuation Using the Example of Load Carrier Development in the Lithium-Ion-Battery Production

Authors: Achim Kampker, Christoph Deutskens, Heiner Hans Heimes, Mathias Ordung, Felix Optehostert

Abstract:

In the past years electric mobility became part of a public discussion. The trend to fully electrified vehicles instead of vehicles fueled with fossil energy has notably gained momentum. Today nearly every big car manufacturer produces and sells fully electrified vehicles, but electrified vehicles are still not as competitive as conventional powered vehicles. As the traction battery states the largest cost driver, lowering its price is a crucial objective. In addition to improvements in product and production processes a non-negligible, but widely underestimated cost driver of production can be found in logistics, since the production technology is not continuous yet and neither are the logistics systems. This paper presents an approach to evaluate cost factors on different designs of load carrier systems. Due to numerous interdependencies, the combination of costs factors for a particular scenario is not transparent. This is effecting actions for cost reduction negatively, but still cost reduction is one of the major goals for simultaneous engineering processes. Therefore a concurrent and phase appropriate cost valuation method is necessary to serve cost transparency. In this paper the four phases of this cost valuation method are defined and explained, which based upon a new approach integrating the logistics development process in to the integrated product and process development.

Keywords: research and development, technology and innovation, lithium-ion-battery production, load carrier development process, cost valuation method

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4291 Optimal-Based Structural Vibration Attenuation Using Nonlinear Tuned Vibration Absorbers

Authors: Pawel Martynowicz

Abstract:

Vibrations are a crucial problem for slender structures such as towers, masts, chimneys, wind turbines, bridges, high buildings, etc., that is why most of them are equipped with vibration attenuation or fatigue reduction solutions. In this work, a slender structure (i.e., wind turbine tower-nacelle model) equipped with nonlinear, semiactive tuned vibration absorber(s) is analyzed. For this study purposes, magnetorheological (MR) dampers are used as semiactive actuators. Several optimal-based approaches to structural vibration attenuation are investigated against the standard ‘ground-hook’ law and passive tuned vibration absorber(s) implementations. The common approach to optimal control of nonlinear systems is offline computation of the optimal solution, however, so determined open loop control suffers from lack of robustness to uncertainties (e.g., unmodelled dynamics, perturbations of external forces or initial conditions), and thus perturbation control techniques are often used. However, proper linearization may be an issue for highly nonlinear systems with implicit relations between state, co-state, and control. The main contribution of the author is the development as well as numerical and experimental verification of the Pontriagin maximum-principle-based vibration control concepts that produce directly actuator control input (not the demanded force), thus force tracking algorithm that results in control inaccuracy is entirely omitted. These concepts, including one-step optimal control, quasi-optimal control, and optimal-based modified ‘ground-hook’ law, can be directly implemented in online and real-time feedback control for periodic (or semi-periodic) disturbances with invariant or time-varying parameters, as well as for non-periodic, transient or random disturbances, what is a limitation for some other known solutions. No offline calculation, excitations/disturbances assumption or vibration frequency determination is necessary, moreover, all of the nonlinear actuator (MR damper) force constraints, i.e., no active forces, lower and upper saturation limits, hysteresis-type dynamics, etc., are embedded in the control technique, thus the solution is optimal or suboptimal for the assumed actuator, respecting its limitations. Depending on the selected method variant, a moderate or decisive reduction in the computational load is possible compared to other methods of nonlinear optimal control, while assuring the quality and robustness of the vibration reduction system, as well as considering multi-pronged operational aspects, such as possible minimization of the amplitude of the deflection and acceleration of the vibrating structure, its potential and/or kinetic energy, required actuator force, control input (e.g. electric current in the MR damper coil) and/or stroke amplitude. The developed solutions are characterized by high vibration reduction efficiency – the obtained maximum values of the dynamic amplification factor are close to 2.0, while for the best of the passive systems, these values exceed 3.5.

Keywords: magnetorheological damper, nonlinear tuned vibration absorber, optimal control, real-time structural vibration attenuation, wind turbines

Procedia PDF Downloads 124
4290 Comparison the Effectiveness of Pain Cognitive- Behavioral Therapy and Its Computerized Version on Reduction of Pain Intensity, Depression, Anger and Anxiety in Children with Cancer: A Randomized Controlled Trial

Authors: Najmeh Hamid, Vajiheh Hamedy , Zahra Rostamianasl

Abstract:

Background: Cancer is one of the medical problems that have been associated with pain. Moreover, the pain is combined with negative emotions such as anxiety, depression and anger. Poor pain management causes negative effects on the quality of life, which results in negative effects that continue a long time after the painful experiences. Objectives: The aim of this research was to compare the effectiveness of Common Cognitive Behavioral Therapy for Pain and its computerized version on the reduction of pain intensity, depression, anger and anxiety in children with cancer. Methods: The research method of this “Randomized Controlled Clinical Trial” was a pre, post-test and follow-up with a control group. In this research, we have examined the effectiveness of Common Cognitive Behavioral Therapy for Pain and its computerized version on the reduction of pain intensity, anxiety, depression and anger in children with cancer in Ahvaz. Two psychological interventions (cognitive behavioral therapy for pain and the computerized version) were compared with the control group. The sample consisted of 60 children aged 8 to 12 years old with different types of cancer at Shafa hospital in Ahwaz. According to the including and excluding criteria such as age, socioeconomic status, clinical diagnostic interview and other criteria, 60 subjects were selected. Then, randomly, 45 subjects were selected. The subjects were randomly divided into three groups of 15 (two experimental and one control group). The research instruments included Spielberger Anxiety Inventory (STAY-2) and International Pain Measurement Scale. The first experimental group received 6 sessions of cognitive-behavioral therapy for 6 weeks, and the second group was subjected to a computerized version of cognitive-behavioral therapy for 6 weeks, but the control group did not receive any interventions. For ethical considerations, a version of computerized cognitive-behavioral therapy was provided to them. After 6 weeks, all three groups were evaluated as post-test and eventually after a one-month follow-up. Results: The findings of this study indicated that both interventions could reduce the negative emotions (pain, anger, anxiety, depression) associated with cancer in children in comparison with a control group (p<0.0001). In addition, there were no significant differences between the two interventions (p<0.01). It means both interventions are useful for reducing the negative effects of pain and enhancing adjustment. Conclusion: we can use CBT in situations in which there is no access to psychologists and psychological services. In addition, it can be a useful alternative to conventional psychological interventions.

Keywords: pain, children, psychological intervention, cancer, anger, anxiety, depression

Procedia PDF Downloads 80
4289 Three Dimensional Model of Full Scale Plate Load Test on Stone Column in Sabkha Deposit: Case Study from Jubail Industrial City - Saudi Arabia

Authors: Hassan. A. Abas, Saad A. Aiban

Abstract:

Soil improvement by means of stone column method is used to improve sabkha soils in order to limit total and differential settlement and to achieve the required bearing capacity. Full-scale plate test was performed on site to confirm the achievement of required bearing capacity at the specified settlement. Despite the fact that this technique is widely used to improve sabkha soils, there are no studies focusing on the behavior of stone columns in such problematic soils. Sabkha soils are known for its high compressibility, low strength and water sensitivity due to loss of salt cementation upon flooding during installation of stone columns. Numerical modeling of plate load test assist to understand complicated behavior of sabkha – stone column interaction. This paper presents a three-dimensional Finite element model, using PLAXIS 3D software, to simulate vertical plate load tests on a stone column installed in sabkha. The predicted settlement values are in reasonable agreement with the field measure values and the field load - settlement curve can be predicted with good accuracy.

Keywords: soil improvement, stone column, sabkha, PLAXIS 3D

Procedia PDF Downloads 388
4288 The Preparation and Characterization of Conductive Poly(O-Toluidine)/Smectite Clay Nanocomposite

Authors: E. Erdem, M. Şahin, M. Saçak

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Smectite is a layered silicate and modified with alkyl ammonium salts to make both the hydrophilic silicate surfaces organophilic, and to expand the clay layers. Thus, a nanocomposite structure can be formed enabling to enter various types of polymers between the layers. In this study, Na-smectite crystals were prepared by purification of bentonite. Benzyltributylammonium bromide (BTBAB) was used as a swelling agent. The mixing time and additive concentration were changed during the swelling process. It was determined that the 4 h of mixing time and 0.2 g of BTBAB were sufficient and the usage of higher amounts of salt did not increase the interlayer space between the clay layers. Then, the conductive poly(o-toluidine) (POT)/smectite nanocomposite was prepared in the presence of swollen Na-smectite using ammonium persulfate (APS) as oxidant in aqueous acidic medium. The POT content and conductivity of the prepared nanocomposite were systematically investigated as a function of polymerization conditions such as the treatment time of swollen smectite in monomer solution and o-toluidine/APS mol ratio. The POT content and conductivity of nanocomposite increased with increasing monomer/oxidant mol ratio up to 1 and did not change at higher ratios. The maximum polymer yield and the highest conductivity value of the composite were 26.0% and 4.0×10-5 S/cm, respectively. The structural and morphological analyses of the POT/smectite nanocomposite were carried out by XRD, FTIR and SEM techniques, respectively.

Keywords: clay, composite, conducting polymer, poly(o-anisidine)

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4287 Preliminary Study of Fermented Pickle of Tabah Bamboo Shoot: Gigantochloa nigrociliata (Buese) Kurz

Authors: Luh Putu T. Darmayanti, A. A. Duwipayana, I. Nengah K. Putra, Nyoman S. Antara

Abstract:

Tabah Bamboo (Gigantochloa nigrociliata (Buese) Kurz) is the indigenous bamboo species which grows in District of Pupuan, Tabanan at Province of Bali. Compared to the others, this shoot has low concentration of hydrocyanide acid (HCN). However, as found for almost of bamboo shoot, its seasonal availability, perishable in nature, and short-lived. This study aimed to gather information about total of lactic acid bacteria (LAB), pH, total acidity, HCN content, detection of LAB’s type involved during fermentation, and organic acids’ profiles of fermented pickles of Tabah bamboo shoot. The pickle was made by natural fermentation with 6 % salt concentration and fermentation conducted for 13 days. The result showed during the fermentation time, in the fourth day we found LAB’s number was highest as much as 72 x 107 CFU/ml and the lowest pH was 3.09. We also found decreasing in HCN from 37.8 ppm at the beginning to 20.52 ppm at the end of fermentation process. The total number of indigenous LAB isolated from the pickle are 48 strains we found 18 out of these had rod shape. For the preliminary study, all of the LAB with rod shape were detected by PCR as member of Lactobacillus spp., in which 17 strains detected as L. plantarum. The organic acids detected during the fermentation were lactic acid with the highest concentration was 0.0546 g/100 g and small amount of acetic acid.

Keywords: fermentation, LAB, pickle, Tabah Bamboo shoot

Procedia PDF Downloads 344
4286 Evaluation of Nanoparticle Application to Control Formation Damage in Porous Media: Laboratory and Mathematical Modelling

Authors: Gabriel Malgaresi, Sara Borazjani, Hadi Madani, Pavel Bedrikovetsky

Abstract:

Suspension-Colloidal flow in porous media occurs in numerous engineering fields, such as industrial water treatment, the disposal of industrial wastes into aquifers with the propagation of contaminants and low salinity water injection into petroleum reservoirs. The main effects are particle mobilization and captured by the porous rock, which can cause pore plugging and permeability reduction which is known as formation damage. Various factors such as fluid salinity, pH, temperature, and rock properties affect particle detachment. Formation damage is unfavorable specifically near injection and production wells. One way to control formation damage is pre-treatment of the rock with nanoparticles. Adsorption of nanoparticles on fines and rock surfaces alters zeta-potential of the surfaces and enhances the attachment force between the rock and fine particles. The main objective of this study is to develop a two-stage mathematical model for (1) flow and adsorption of nanoparticles on the rock in the pre-treatment stage and (2) fines migration and permeability reduction during the water production after the pre-treatment. The model accounts for adsorption and desorption of nanoparticles, fines migration, and kinetics of particle capture. The system of equations allows for the exact solution. The non-self-similar wave-interaction problem was solved by the Method of Characteristics. The analytical model is new in two ways: First, it accounts for the specific boundary and initial condition describing the injection of nanoparticle and production from the pre-treated porous media; second, it contains the effect of nanoparticle sorption hysteresis. The derived analytical model contains explicit formulae for the concentration fronts along with pressure drop. The solution is used to determine the optimal injection concentration of nanoparticle to avoid formation damage. The mathematical model was validated via an innovative laboratory program. The laboratory study includes two sets of core-flood experiments: (1) production of water without nanoparticle pre-treatment; (2) pre-treatment of a similar core with nanoparticles followed by water production. Positively-charged Alumina nanoparticles with the average particle size of 100 nm were used for the rock pre-treatment. The core was saturated with the nanoparticles and then flushed with low salinity water; pressure drop across the core and the outlet fine concentration was monitored and used for model validation. The results of the analytical modeling showed a significant reduction in the fine outlet concentration and formation damage. This observation was in great agreement with the results of core-flood data. The exact solution accurately describes fines particle breakthroughs and evaluates the positive effect of nanoparticles in formation damage. We show that the adsorbed concentration of nanoparticle highly affects the permeability of the porous media. For the laboratory case presented, the reduction of permeability after 1 PVI production in the pre-treated scenario is 50% lower than the reference case. The main outcome of this study is to provide a validated mathematical model to evaluate the effect of nanoparticles on formation damage.

Keywords: nano-particles, formation damage, permeability, fines migration

Procedia PDF Downloads 621